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عنوان فارسی مقاله:

یادگیری برنامه درسی

عنوان انگلیسی مقاله:

Curriculum Learning

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ارائه شده از دانشگاه گروه IRO، مونترال
نویسندگان Yoshua Bengio, Jérôme Louradour, Ronan Collobert, Jason Weston
رفرنس دارد 
کد محصول 9218
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وضعیت ترجمه انجام شده و آماده دانلود
کیفیت ترجمه طلایی⭐
تعداد صفحات ترجمه تایپ شده با فرمت ورد با قابلیت ویرایش  16صفحه با فونت 14 B Nazanin
ترجمه عناوین تصاویر ترجمه شده است  
ترجمه متون داخل تصاویر ترجمه نشده است 
درج تصاویر در فایل ترجمه درج شده است  
درج فرمولها و محاسبات در فایل ترجمه به صورت عکس درج شده است  
منابع داخل متن به فارسی درج شده است 

 

فهرست مطالب

چکیده

1- مقدمه

2- نکاتی در خصوص مسئله بهینه سازی سخت یادگیری شبکه های عصبی عمیق

3- برنامه درسی به عنوان روش مستمر

4- آزمایشات اسباب بازی با معیار محدب

4-1 مثال های شفاف تر به تعمیم بهتر و سریع تر کمک می کنند

4-2 معرفی تدریجی مثال های سخت تر موجب تسریع آموزش انلاین می شود

5- آزمایشاتی بر روی تشخیص شکل

6- آزمایشات بر روی مدل سازی زبان

6-1 معماری

6-2 آزمایشات

7- بحث و کار های آینده

 

بخشی از ترجمه

چکیده

انسان ها و حیوانات زمانی بهتر یاد می گیرند که مثال هایی به طور سازمان دهی شده و به شکلی معنی دار( نه به طور تصادفی) به آن ها ارایه شود که به تدریج این مثال ها موجب شفاف تر شدن تدریجی مفاهیم پیچیده شود. در این جا ما با این راهبرد های آموزشی در زمینه یادگیری ماشینی آشنا شده و آن ها را یادگیری برنامه آموزشی می نامیم. در مطالعات تحقیقاتی اخیر، سختی آموزش در حضور معیار های آموزشی غیر محدب ( برای شبکه های عصبی تصادفی و قطعی عمیق)، ما به بررسی آموزش برنامه درسی در شرایط مختلف می پردازیم.آزمایشات نشان می دهند که پیشرفت های قابل توجهی را می توان در زمینه تعمیم و کلیت بخشی حاصل کرد. فرضیه ما این است که آموزش برنامه درسی هم بر روی سرعت همگرایی فرایند آموزشی به میزان حداقل اثر داشته و هم در حضور معیار های غیر محدب، بر روی کیفیت کمینه محلی اثر دارد. آموزش برنامه درسی یک شکل ویژه از روش مستمر است( یک راهبرد عمومی برای بهینه سازی جهانی توابع غیر محدب است).

 

7- بحث و کار های آینده

ما با یک سوالی شروع می کنیم که از مطالعات علوم شناختی قبلی هنوز به صورت بی پاسخ مانده است( المان 1993، راد و پلات 1999):آیا الگوریتم های یادگیری ماشینی می توانند از راهبرد برنامه درسی منتفع شوند؟ نتایج آزمایش ما در شرایط مختلف شواهدی را در خصوص پاسخ مثبت به این سوال نشان می دهد. به این ترتیب برخی از راهبرد های برنامه درسی بهتر از راهبرد های دیگر هستند و برخی نیز برای کار های دیگر بی اهمیت هستند( راد و پلات 1999) و این که نتایج بهتر را می توان با مجموعه داده های مربوط به راهبرد های آموزشی مناسب تر بدست اورد. با این همه، هنر آموزش سخت است و انسان ها در مورد ترتیب معرفی مطالب به دانش اموزان به توافق نرسیده اند. از دیدگاه یادگیری ماشینی، سوالات مهم به صورت چرایی و چگونگی است. این برای کمک به طراحی بهتر راهبرد های برنامه درسی در راستای خودکار سازی فرایند مهم است. در این جا فرضیاتی برای توجیه مزایای بالقوه راهبرد برنامه اموزشی ارایه می شود

 

بخشی از مقاله انگلیسی

Abstract

Humans and animals learn much better when the examples are not randomly presented but organized in a meaningful order which illustrates gradually more concepts, and gradually more complex ones. Here, we formalize such training strategies in the context of machine learning, and call them “curriculum learning”. In the context of recent research studying the difficulty of training in the presence of non-convex training criteria (for deep deterministic and stochastic neural networks), we explore curriculum learning in various set-ups. The experiments show that significant improvements in generalization can be achieved. We hypothesize that curriculum learning has both an effect on the speed of convergence of the training process to a minimum and, in the case of non-convex criteria, on the quality of the local minima obtained: curriculum learning can be seen as a particular form of continuation method (a general strategy for global optimization of nonconvex functions).

 

7 Discussion and Future Work

We started with the following question left from previous cognitive science research (Elman, 1993; Rohde & Plaut, 1999): can machine learning algorithms benefit from a curriculum strategy? Our experimental results in many different settings bring evidence towards a positive answer to that question. It is plausible that some curriculum strategies work better than others, that some are actually useless for some tasks (as in Rohde and Plaut (1999)), and that better results could be obtained on our data sets with more appropriate curriculum strategies. After all, the art of teaching is difficult and humans do not agree among themselves about the order in which concepts should be introduced to pupils. From the machine learning point of view, once the success of some curriculum strategies has been established experimentally, the important questions are: why? and how? This is important to help us devise better curriculum strategies and maybe automate that process to some extent. Here we proposed a number of hypotheses to explain the potential advantages of a curriculum strategy:

 

 

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یادگیری برنامه درسی

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Curriculum Learning

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1. Introduction

Land degradation is one of the most serious global environmental issues of our time (Dregne, 1998; Reynolds and Stafford Smith, 2002). Land use activities are among the key drivers of land degradation worldwide. These activities shape the land surface and can induce substantial changes to natural phenomena (Steffen et al., 2007). Human activities are at the heart of several environmental challenges. Actually, Humans dominate, transform and modify ecosystems (Zika and Erb, 2009) to their own benefit, yet often at the expense of the global ecological patterns and processes. Sound soil and water conservation measures (Bou Kheir et al., 2006) are needed to mitigate the pervasive and disruptive impact of land degradation on sustainable natural resource management. Moussa et al. (2002) and Souchère et al. (2005) argue that a spatially distributed assessment of erosion risk is mandatory and must be performed before implementing any effective soil conservation measure. Other authors advocate for the use of geoindicators, which are aggregate and efficient proxies of surface processes in the assessment of land degradation (Berger, 1996; Berger, 1997; Dumanski and Pieri, 2000; Gupta, 2002; Hammond et al., 1995; Morton, 2002; Zaz and Romshoo, 2012; Zuquette et al., 2004). Moreover, recent advances in scientific computing, remote sensing, and GIS technologies enable cheap and fast processing of large and complex datasets. This may help alleviate a major practical challenge inherentin implementing erosionmodels (Merritt et al., 2003), as they are data-intensive and time consuming (Vrieling et al., 2006). However, accessing clean data is a pivotal issue in Sub-Saharan African countries that often lack of wellfunctioning data collection systems. Interestingly, Van Rompaey and Govers (2002) show that when data are scare and/or unreliable, simple erosion models provide a more accurate assessment than complex ones. Complex erosion models are often adequate for small scale applications, but loose tractability for large scale implementations, as pointed out by Kirkby et al. (1996), Schoorl et al. (2000), Yair and Raz-Yassif, (2004), among others. Moreover, less data-consuming methods seem more appealing to decision makers (Renschler and Harbor, 2002). According to Bayramin et al. (2003); ICONA (1991, 1997); Zaz and Romshoo (2012), the ICONA model is one of the easiest and flexible qualitative methods for assessing and mapping soil erosion risk. This model has been used by European Union (EU) countries and Mediterranean states (e.g., Turkey, Tunisia, Syria, and Egypt), as documented by Bayramin et al. (2003). In Benin, Atacora Mountain chain is of high ecological and biological value (Adomou, 2005). It has an exclusive vegetation type (the Synsepalum passargei-Broenadia salicina riparian community) and the two Beninese endemics Thunbergia atacorensis and Ipomoea beninensis (Akoègninou and Lisowski, 2004). Soil fertility loss, physical and chemical soil degradation are a few threats identified by many authors (Adegbidi et al., 1999; Mulder, 2000; Tente and Sinsin, 2005). Their harmful effects are potentially increased by steep slope, shallow soil, strong demographic pressures, and transborder transhumance from Sahelian countries such as Burkina Faso and Niger (Meurer, 1994). There is a narrow body of literature addressing global and detailed estimation of land alteration in Atacora Mountain. Tente and Sinsin (2005) investigate at the scope of some hills of Atacora Mountain and find that erosion reduces, on average, 8.6 cm/ ha/year of the soil thickness. The 2008 “National Self-assessment of Capacities to Enhance for the Management of Global Environment” report reveals that Atacora Mountain and its surrounding areas are characterized by slight, average and extreme degradation status (ANCR-GEM et al., 2008). This report is the most recent large scale assessment of land degradation in the study area. Nonetheless,this assessmentis rough and only relies on expert-folk opinions. This study aims at evaluating and determining the erosion risk status of Atacora Mountain and its surrounding areas using GIS and ICONA model.


بخشی از مقاله انگلیسی:

For a legal historian of twentieth-century feminism, Obergefell’s valence is especially complex. This Essay measures Obergefell against two legacies of second-wave feminist legal advocacy: the largely successful campaign to make civil marriage formally gender-neutral, and the lesserknown, less successful struggle against laws and practices that penalized women who lived their lives outside of marriage. Obergefell indirectly acknowledges marriage equality’s debt to the former legacy, and utterly disregards the latter. But the history of transformational change invoked in Obergefell suggests the potential for marriage equality to become more than an affirmation of marriage’s legal supremacy. *** The feminist legacy most apparent in Obergefell is the transformation of marriage law. Justice Kennedy’s opinion endorses wholeheartedly the historical account articulated by feminist scholars, most prominently Nancy Cott, since the turn of the twenty-first century.3 Marriage, on this view, is a dynamic institution, transformed since the Founding from an inegalitarian, racially exclusive, socially mandatory, and presumptively permanent status by state-level reforms and federal constitutional intervention. Exhibit A in this story of evolutionary change is the abolition of coverture and the replacement of highly differentiated and unequal rights and duties for husbands and wives with gender-neutral partnerships that spouses may enter and exit voluntarily. Historically, as a matter of formal law if not always social reality, marriage prescribed gender-differentiated and unequal roles for husbands and wives and the subordination of wives’ legal identity through coverture.4 The reigning marital bargain required men to provide economic support to their wives and children; in exchange, women owed their husbands personal services such as homemaking, caregiving, and consortium. At common law, married women could not make contracts, hold property in their own names, sue or be sued. A husband’s prerogatives included the right to determine the family’s domicile, to chastise wayward dependents, and to demand sexual access to his wife. Thanks both to feminist struggle and broader economic and social changes, many of married women’s formal legal disabilities receded over the course of the nineteenth and early twentieth centuries. Married Women’s Property Acts, the Nineteenth Amendment, and early antidiscrimination laws blunted the sharpest edges of coverture.5 But as late as 1961 the Supreme Court famously declared that women’s role “as the center of home and family life” justified exempting them from jury service,6 and the sex-differentiated laws of marriage and divorce remained on the books in most jurisdictions.7 Laws and government policies, including the provision of key social insurance benefits, not only assumed but encouraged and rewarded a male breadwinner/female homemaker division of labor.8 The reigning liberal consensus followed the 1965 Moynihan Report in recommending that black families adopt this white middle-class patriarchal ideal or risk a dismal descent into poverty, illegitimacy, and violence.9 By the 1970s, many policy makers worried that the “culture of pathology” that Moynihan saw in the “Negro family” would spread across American society if women achieved the equal employment opportunity feminists sought.10 Feminists such as Pauli Murray and Eleanor Holmes Norton countered with their own vision of family life, anchored by the egalitarian marriages African American middle-class families pioneered.11 They insisted that women’s equal opportunity in the workplace and at home was essential, not antithetical, to racial progress, and that black women’s strength and self-sufficiency could serve as a model for white women constrained by restrictive sex-role expectations. A litigation campaign led by law professor and ACLU attorney Ruth Bader Ginsburg wrote this vision of egalitarian marriage into constitutional law.12 Though feminists did not win ratification of the federal Equal Rights Amendment (ERA), they achieved many of the ERA’s original goals through state-level reforms to marriage and divorce law, and through federal and state constitutional rulings that applied heightened judicial scrutiny to sex-based classifications.13 In cases such as Frontiero v. Richardson, 14 Weinberger v. Wiesenfeld, 15 and Califano v. Goldfarb, 16 Ginsburg and her allies persuaded the Court that the federal government could not constitutionally distinguish between husbands and wives or between widows and widowers in the allocation of military and Social Security benefits. By the 1980s, as a matter of formal law—though not of social reality—feminist advocacy made marriage a gender-neutral institution, a presumptively equal partnership of spouses with identical, reciprocal legal rights and responsibilities.17


 

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مشخصات و وضعیت ترجمه فارسی این مقاله (Word)
تعداد صفحات ترجمه تایپ شده با فرمت ورد با قابلیت ویرایش و فونت 14 B Nazanin 12 صفحه
ترجمه عناوین تصاویر و جداول ترجمه شده است  
ترجمه متون داخل تصاویر ترجمه شده است  
ترجمه متون داخل جداول ترجمه شده است  
درج تصاویر در فایل ترجمه درج شده است  
درج جداول در فایل ترجمه درج شده است  
درج فرمولها و محاسبات در فایل ترجمه به صورت عکس درج شده است  
منابع داخل متن به صورت عدد درج شده است  

 


 

چکیده

1-مقدمه

2- ترکیب داده های چند سنسوره

3- شبکه عصبی مصنوعی

4- نتایج آزمایشگاهی

5- نتایج


  • بخشی از ترجمه:

چکیده

این مقاله یک سیستم مسیریابی را بر اساس شبکه عصبی مصنوعی (ANN) المان ارائه می دهد. عمل ترکیب داده ها حاصل از سنسورهای مختلف بوسیله ANN آموزشی درک شده است. تعیین موقعیت در فضا موضوعی غیر خطی است، از این رو هر نوع ANN را نمی توان برای این عمل بکار برد. ANN المان به علت ساخت و کاربرد موفق آن در مسائل غیر خطی که به پیشبینی نیازمندند، انتخاب شده است. شبکه المان از سه لایه تشکیل شده است. لایه ای از واحدهای لایه ای مخفی که به لایه مخفی متصل شده است. لایه حساس به متن ذخیره مقادیر واحدهای مخفی قبلی را قادر میسازد. با این لایه، پیشبینی در دستورات سلسه مراتبی ممکن می باشد. این امر تاثیر حافظه متنی است که اطلاعات حوادث قبلی در آن ذخیره میگردد. شبکه عصبی تک محوره استاندارد دیگری قادر به فراهم نمودن این نوع عملکرد نیست. سیستم متشکل از سنسورهای MEMS (سیستم های ریز الکترومکانیکی) می باشد که بر پایه IMU (واحد اندازه گیری لختی) استوار است. IMU از ژیروسکوپ ها، شتاب سنج ها و مغناطیس سنج هایی تشکیل شده که شتاب های سه بعدی خطی و نرخهای زاویه ای را ارائه می دهد. این یک مجموعه کلاسیک از سنسورها برای تعیین موقعیت فضایی است. این مطالعه نتایج کاربرد الگوریتم هایی برای تعیین موقعیت فضایی با استفاده از ANN المان را ارائه می دهد. نمونه داده های ANN آزمایشی حین تست پرواز کوادکوپتر جمع آوری گردید. این مقاله عملکرد اشکال مختلف ANN المان را ارائه میدهد. سیستم ارائه شده تجمیع آسان سایر سنسورها مانند دریافت کننده های GPS/GLONASS را ممکن می سازد.

5- نتایج

نتایج بدست آمده نشان میدهد که فرضیات درست بوده اند. با مقایسه نتایج می¬توان نتیجه گرفت که مقادیر بدست آمده با استفاده از ANN چندان با محاسبات حاصل از الگوریتم AHRS تفاوتی ندارند. با این حال، با مقایسه مقادیر خروجی ANN و مقادیر محاسبه شده می¬توان خطای بزرگی را مشاهده نمود. این خطا به وسیله دینامیک بالای داده های ورودی شبکه عصبی حاصل شده است. مطالعات آینده به مجموعه داده های بیشتری برای فراگیری شبکه نیاز دارند. این نتایج نشان می¬دهند که می¬توانیم به طور موفقیت آمیزی ANN را به عنوان جایگزین محاسبات پیچیده استفاده کنیم. با این حال، باید تحقیق جامعی بر انتخاب پارامتری ANN انجام شود. تحقیقات آینده باید با سنسورهای اضافی مانند دریافت کننده های GPS و فشار سنج غنی گردد. این سنسورها دقت موقعیت یابی را بهبود می بخشند ، تحقیق را بسیار متنوع نموده و متغیرهای بیشتری را برای تحلیل ایجاد می¬نماید. همچنین برای مقایسه نتایج با انواع دیگر شبکه های عصبی مصنوعی برنامه ریزی شده است.


  • بخشی از مقاله انگلیسی:

Abstract

The paper presents a navigation system based on Elman Artificial Neural Network (ANN). The task of data fusion from different sensors is realized by trained ANN. Determining position in space is an issue of nonlinear hence. Not every type of ANN is used for such a task. Choice of Elman ANN was dictated by its construction and successfully applications to nonlinear problems requiring prediction. Elman network is composed of three layers. Comprises a layer of hidden layer units context which is connected to the hidden layer. Context-sensitive layer allows for store the values of previous hidden units. With this layer prediction is possible in sequential order. This is the effect of contextual memory where information is stored about what it was before. This kind of functionality is not able to provide any other standard neural network unidirectional. The system consists of MEMS (Micro Electro-Mechanical Systems) sensors, which are based on IMU (Inertial Measurement Unit). IMU is composed from gyroscopes, accelerometers and magnetometers which provide three dimensional linear accelerations and angular rates. This is a classic set of sensors for determining the position in space. The study presents the results of the implementation of algorithms for determining the position in space using trained Elman ANN. The data samples to train ANN were collected during the test flight of Quadrocopter. Paper presents the performance for different configurations of Elman ANN. Presented system provides easy addition of other sensors e.g. GPS/GLONASS receiver.


5. Conclusions

The obtained results allow to conclude that the assumptions were correct. Comparing the results it can be concluded that the values obtained using the ANN do not differ significantly from these calculated using the AHRS algorithm. However, comparing the differences between the values of the ANN output and the calculated values can be seen a large error values. This is caused by the high dynamics of the neural network input data. Future studies need to prepare more data sets to learn the network. This shows that we can successfully use the ANN as an alternative to complicated calculations. However, one should carry out a more thorough investigation of the selection of ANN parameters. Future research should be enriched with additional sensors such as GPS receiver and barometer. These sensors will improve the positioning accuracy. And that will make the research will be more varied with more variables for analysis. It is also planned to compare the results with the use of other types of artificial neural networks.

 

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بخشی از ترجمه فارسی مقاله:

1. مقدمه
یک هیاهویی از محصولات پروبیوتیک سلامت محور در طی یک دهه اخیر به وجود آمده است. فعالیت بیولوژیک باکتری های پروبیوتیک، مدیون توانایی اتصال آن ها به انتروسیت ها می باشد که از این رو، با روش مستثنی کردن رقابتی، مانع از اتصال پاتوژن های روده ای، می شود. باکتری های پروبیوتیک، به دلیل خصوصیات سودمند مختلف خودشان، از جمله کاهش علایم سندرم روده تحریک پذیر، اثرات تنظیم کنندگی ایمنی و کاهش کلسترول، در صنعت غذایی مورد استفاده قرار گرفته اند (FAO/WHO, 2006). شمول باکتری های پروبیوتیک در محصولات تخمیری، ارزش آن ها را به عنوان غذاهای با عملکرد درمانی بهتر افزایش می دهد. برای همه ی محصولاتی که ادعای سلامت پروبیوتیک دارند لازم است که حداقل CFU/ml106 باکتری پروبیوتیک، تا تاریخ انقضا داشته باشند، چون مینیمم سطح درمانی در هر روز، 109-108 سلول در نظر گرفته می شود (Kailasapathy & Chin, 2000). کریمی، مرتضویان و دا کروز (2011) بیان کردند که محصولات پروبیوتیک زمانی که 100 گرم در روز مصرف می شوند حدود 109 سلول زنده را درون روده تحویل می دهند. گزارش ها نشان دهنده ی بقا ضعیف پروبیوتیک ها در محصولات غذایی و همچنین در سیستم معدی روده ای انسان می-باشد. بقا پروبیوتیک ها در یک محصول در طی مصرف، برای اثر بخشی آن ها دارای اهمیت است، چون بقا آن ها در طی فراوری و ذخیره سازی محصولات غذایی ضروری است (Mortazavian, Mohammadi, & Sohrabvandi, 2012). انتخاب سویه های پروبیوتیک بهتر و ارائه ی لایه بندی فیزیکی به آن ها، برای افزایش بقا آن ها، از جمله، استفاده از پروبیوتیک های مناسب و ترکیب نرمالی از پروبیوتیک ها و پری بیوتیک ها (سین بیوتیک ها) می تواند تحویل پروبیوتیک های زنده ی کافی در محصولات غذایی عملکردی به مصرف کنندگان را افزایش دهد. بقا پروبیوتیک-ها در ماتریکس غذایی توسط عواملی مانند PH، اسیدی شدن در طی ذخیره سازی محصولات تخمیری، تولید هیدروژن پروکسید، سمیت اکسیژن، دماهای فراوری و ذخیره سازی، نرخ و نسبت تلقیح، میکروانکپسولاسیون و پایداری در طی ذخیره سازی تحت تاثیر قرار می گیرد (Mortazavian et al., 2012). به منظور فعالیت به عنوان پروبیوتیک در دستگاه گوارش (GIT) و به منظور اعمال اثرات سودمند خودشان روی میزبان، برای باکتری ها ضروری است که مکانیسم های محافظتی برای مقاومت در برابر PH پایین در معده، آنزیم های هاضمه و صفرای موجود در روده کوچک داشته باشند (Argyri et al., 2012). مدل معدی روده ای in vitro (سیستم تک ظرفی) ترجیحا برای تقلید این میکرو محیط GIT مورد استفاده قرار می گیرد.
میکروانکپسولاسیون به عنوان یک فرایندی تعریف می شود که در آن، سلول ها درون یک غشا حفظ می شوند تا آسیب سلولی و مرگ را کاهش دهند که ذراتی در حد نانومتر (نانوانکپسولاسیون)، میکرومتر (میکروانکپسولاسیون) یا مقیاس میلی متری ایجاد می کنند (Burgain, Gaiani, Linder, & Scher, 2011). انکپسولاسیون سلول های پروبیوتیک را پایدار می کند، که به طور معنی داری بقا و پایداری آن ها در تولید و مدیریت غذاهای عملکردی و همچنین در طی هیدراتاسیون مجدد و لیپوفیلیز شدن آن ها را افزایش می دهد. آن همچنین از فعالیت متابولیک پروبیوتیک ها در دستگاه معدی روده ای محافظت می کند (Picot & Lacroix, 2004) و پایداری در طی ذخیره سازی درازمدت را تضمین می کند (Zuidam & Nedovic, 2010). به علاوه، انکپسولاسیون، خصوصیات چشایی غذا را بهبود می دهد و پایدار می کند و همچنین به توزیع همگن پروبیوتیک ها در کل محصول کمک می کند (Krasaekoopt, Bhandari, & Deeth, 2003). به نظر می رسد که قارچ ها یک کاندیدای بالقوه برای پری بیوتیک ها باشند چون آن ها حاوی کربوهیدرات هایی مانند کیتین، همی سلولز، بتا و آلفا گلوکان، مانان، زایلان و گالاکتان-ها هستند. مطالعات پیشین پیشنهاد می کنند که پلی ساکاریدهای گرفته شده از قارچ، خصوصیات تعدیل کننده ی ایمنی مانند افزایش تکثیر لنفوسیت و تولید آنتی بادی (Bao, Liu, Fang, & Li, 2001) و همچنین خصوصیات ضد سرطانی (Wasser, 2002) و کمک به حذف کلسترول و جلوگیری از چاقی دارند. آخرین یافته توسط هرست و همکارانش (2009) و تسایی و همکارانش (2009)، به ترتیب، خصوصیات ضد میکروبی و آنتی اکسیدانی قارچ ها را نشان داد. به جز خصوصیات پزشکی آن ها، قارچ های خوراکی، بهبود سلامتی معنی داری را نشان دادند چون آن ها محتوای پایینی از کالری، سدیم، چربی و کلسترول دارند و در عین حال در پروتئین، کربوهیدرات، فیبر، ویتامین ها و مواد معدنی غنی هستند. این خصوصیات تغذیه ای به قارچ ها، این پتانسیل را اعطا می کند که یک مکمل غذایی و همچنین یک عامل دارویی باشند. آن ها قادر به دستکاری ترکیب میکروبیوتای کولون در روده انسان توسط مهار پاتوژن های اگزوژن هستند (Rycroft, Jones, Gibson, & Rastall, 2001)، بنابراین، سلامت میزبان را بهبود می دهند (Roberfroid, 2002). سینیتسیا و همکارانش (2009) نشان دادند که عصاره های قارچ قادر به تحریک رشد پروبیوتیک ها هستند. نوشیدنی های پروبیوتیک عموما حاوی باکتری-های زنده هستند. آن ها همچنین باید حاوی یک منبعی از مواد مغذی برای باکتری ها برای تغذیه باشند (Savini et al., 2010). در نتیجه، مسایل کوتاه شدن ذخیره سازی و دوام در قفسه برای برخی محصولات زنده وجود دارد. به علاوه، رقابت برای مواد مغذی بین سویه های باکتریایی درون یک نوشیدنی یک عارضه ی مهم دیگر می باشد. به علاوه، پروبیوتیک های مایع نیاز به نگه داری در یخچال دارند. از طرف دیگر، پودرهای پروبیوتیک شامل پروبیوتیک هایی هستند که تحت دما و فشار پایین با سرما خشک شده اند بدون اینکه سلول ها آسیب ببینند. این یک رشد مناسب را در حالت معلق برای ذخیره سازی درازمدت باکتری های پروبیوتیک فراهم می کند. بعداز هضم، به محض اینکه مجددا رطوبت در دسترس قرار می گیرد، آن ها مجددا هیدراته می شوند و سپس مجددا یک نسبتی از سلول ها، همانند چیزی که قبل از خشک شدن با سرما بوده اند، آغاز به تقسیم شدن می-کنند. محققین، فهمیده اند که پروبیوتیک هایی که مجددا هیدراته شده اند، قادر به فراهم کردن موثر مزایای مربوطه ی خودشان هستند (Bohbot & Cardot 2012). اینکه آیا نگه داری در یخچال برای پروبیوتیک ها مورد نیاز هست یا نه بستگی به سویه های معین دارد، برخی از آن ها مقاوم به گرما و قفسه هستند و برخی از آن ها اینطور نیستند. بنابراین، کار اخیر برای مطالعه ی اثربخشی میکروکپسولاسیون در حفاظت از LAB از اسید، صفرا، و آنزیم های گوارشی برنامه ریزی شده است. این کار همچنین به ارزیابی اثربخشی انکپسولاسیون LAB با مولکول های پری بیوتیک به منظور افزایش قابلیت بقا آن ها در طی ذخیره سازی در ماتریکس غذایی خشک کمک کرده است.

بخشی از مقاله انگلیسی:

1. Introduction

There has been an explosion of health-based probiotic products since over a decade. The biological activity of probiotic bacteria owes to their ability of attachment to enterocytes thereby inhibiting the enteric pathogens from binding as a result of competitive exclusion. Probiotic bacteria are used in the food industry due to various beneficial properties including reduction of irritable bowel syndrome symptoms, immunomodulatory effects, and cholesterol reduction (FAO/WHO, 2006). Inclusion of probiotic bacteria in fermented products enhances their value as better therapeutic functional foods. It is necessary for all products having probiotic health claims to have minimum 106 CFU/mL probiotic bacteria till expiry date, since minimum therapeutic level per day is considered to be 108 –109 cells (Kailasapathy and Chin, 2000). Karimi et al. (2011) stated that probiotic products when consumed 100 g per day deliver about 109 viable cells into the intestine. Reports indicate poor survival of probiotics in food products as well as in the human gastro-intestinal system. Viability of probiotics in a product during consumption is important for their efficacy, as their survival is essential during processing and storage of food products (Mortazavian et al., 2012). Selecting better probiotic strains and providing them physical layering to enhance their survival, including the use of appropriate prebiotics and the optimal combination of probiotics and prebiotics (synbiotics), can increase the delivery of sufficient viable probiotics in functional food products to the consumers. Viability of probiotics in food matrix is affected by factors like pH, acidification during storage of fermented products, production of hydrogen peroxide, oxygen toxicity, processing and storage temperatures, rate and proportion of inoculation, micro-encapsulation, and stability during storage (Mortazavian et al., 2012). In order to act as probiotic in the gastrointestinal tract (GIT) and to exert their beneficial effect on the host it is essential for the bacteria to have protective mechanisms to withstand the low pH in the stomach, digestive enzymes, and bile in the small intestine (Argyri et al., 2012). In-vitro gastro intestinal model (one pot system) is preferably used to mimic this GIT micro-environment. Microencapsulation is defined as a process in which the cells are retained within a membrane to reduce cell injury and death, producing particles in the nanometer (nanoencapsulation), micrometer (microencapsulation) or millimeter scale (Burgain et al., 2011). Encapsulation stabilises the probiotic cells, significantly enhancing their viability and stability in the production and handling of functional food as well as during their rehydration and lyophilisation. It also preserves the metabolic activity of probiotics in the gastrointestinal tract (Picot and Lacroix, 2004), and ensures viability during long-term storage (Zuidam and Nedovic, 2010). In addition, encapsulation improves and stabilises the sensory properties of the food as well as aids in the homogeneous distribution of probiotics throughout the product (Krasaekoopt et al., 2003). Mushrooms seem to be a potential candidate for prebiotics as it contains carbohydrates like chitin, hemicellulose, β and α-glucans, mannans, xylans, and galactans. Previous studies suggested that the polysaccharides from mushroom have immunomodulating properties like enhancement of lymphocyte proliferation and antibody production (Bao et al., 2001) as well as antitumor properties (Wasser, 2002) and help in cholesterol removal and prevention of obesity. Latest finding by Hearst et al. (2009) and Tsai et al. (2009) revealed antimicrobial and antioxidant properties of mushrooms, respectively. Other than its medicinal properties, edible mushrooms also show significant health improvement as they have low content of calories, sodium, fat, and cholesterol, while they are rich in protein, carbohydrate, fibre, vitamins, and minerals. These nutritional properties give mushrooms the potential to become a food supplement as well as a pharmaceutical agent. They are able to manipulate the composition of colonic microbiota in human gut by inhibition of exogenous pathogens (Rycroft et al., 2001), thus improving the host health (Roberfroid, 2002). Synytsya et al. (2009) showed that mushroom extracts were able to stimulate the growth of probiotics. The probiotic drinks generally contain live bacteria. They must also contain a source of nutrition for the bacteria to feed upon (Savini et al., 2010). Consequently, there is storage and shelf-life issue shortened for some live products. Furthermore, competition for nutrition between bacterial strains within a drink is another important complication. In addition, liquid probiotics all require refrigeration. On the other hand probiotic powders consist of probiotics that have been freeze-dried under low temperature and pressure without damaging the cells. This provides a suitable growth suspended state for the long-term storage of probiotic bacteria. Once moisture becomes available again after ingestion they rehydrate and subsequently, a proportion of cell start to divide again as before being freeze-dried. Researchers have found that the rehydrated probiotics are capable of effectively providing their respective benefits (Bohbot and Cardot, 2012). Whether or not refrigeration is required for probiotics is dependent upon the actual strains, some of which are heat and shelf stable and some of which are not. Hence, the present work was planned to study the efficiency of microencapsulation in protecting the LAB from acid, bile, and digestive enzymes. This work also aimed to evaluate the efficiency of encapsulation along with prebiotic molecules to increase their survivability during storage in dry food matrix.


بخشی از مقاله انگلیسی:

Introduction

Breast milk is a complex, living nutritional fluid that contains antibodies, enzymes, nutrients and hormones. Breastfeeding has many benefits for babies such as fewer infections, increased intelligence, probable protection against overweight and diabetes and, for mothers, cancer prevention.1 The World Health Organization recommends mothers breastfeed exclusively for six months postpartum. Breastfeeding is influenced by many complex physiological and psychosocial factors. While most women have a desire to breastfeed, some do not. In high-income countries such as Australia the duration of breastfeeding is shorter than in lowand middle-income countries. A 2011 Australian Institute of Health and Welfare survey estimated that only 56% of infants younger than six months were exclusively breastfed, and by 12 months this dropped to 30%. While breastfeeding should be encouraged, a woman’s right to choose not to breastfeed should be respected. By understanding the reasons for their decision, strategies can be offered to support their choice.

Physiology of lactation

Milk production begins between 10 and 22 weeks gestation. Within 48 hours of delivery, the mother produces a small amount of milk, mainly colostrum. However, it is not until serum progesterone decreases sufficiently, up to four days postpartum, that milk supply becomes more plentiful. Lactogenesis may be delayed if the baby is premature. Milk production is controlled by a complex interplay of hormones and neurotransmitters. Prolactin is secreted by the anterior pituitary in response to nipple stimulation. Its release is inhibited by dopamine from the hypothalamus. Within a month of delivery, basal prolactin returns to pre-pregnant levels in nonbreastfeeding mothers. It remains elevated in nursing mothers, with peaks in response to infant suckling. Drugs that act on dopamine can affect lactation. In response to suckling, oxytocin is released from the posterior pituitary to enable the breast to let down milk. Oxytocin release is inhibited by catecholamines produced if the mother is stressed or experiencing pain. The feedback inhibitor of lactation is a peptide found in breast milk. If the milk is not removed, the inhibitor will stop milk production. When the baby cannot suckle, expressing the milk will remove the inhibitor and encourage more production.


بخشی از مقاله انگلیسی:

I. INTRODUCTION

The past three decades have witnessed the rapid development in the research field of autonomous driving, which attracts considerable research interest and efforts from both academia and industry. During the famous AGV competitions, the DARPA Grand Challenges and the DARPA Urban Challenge, autonomous ground vehicles had demonstrated their great potentials to improve driving safety, efficiency and comfort in both off-road and on-road environments [1]-[3]. These competitions showed significant advances over the-state-of-the-art in autonomous driving technology and stimulated extensive interest in the AGV research field as well. Recently, partially automated control functions have already been applied in the driver assistant systems and several automotive companies even make their research and development plans for producing future autonomous cars. Nevertheless, there is still a number of challenges to be faced for developing truly reliable and robust fully-autonomous driving vehicles to handle various realistic situations in the real world. As is well-known that the development and application of AGVs require the integration of the-state-of-the-art technologies, ranging from perception, localization to navigation and control [4]. As the core modules, both local motion planner and path tracking controller play a significant role in guaranteeing safety and improving driving comfort. In order to track the reference path accurately and robustly, many researchers developed Lyapunov-based feedback control laws by considering vehicle kinematics and dynamics, such as sliding model control, backstepping control and so on. To adapt high speed and varying terrain conditions and improve control accuracy and robustness, some researchers explore cascaded or multi-tiered control strategies and focusing on minimizing lateral errors in the outer loop, and stabilizing yaw motions via steering actions in the inner loop [5]. To reject model uncertainties and external disturbances, tire sideslip angles and inertial effects are taken into account. However, most of these controllers formulate the tracking control problem into a regulation problem, which primarily concerns with current cross-track error information (such as lateral and heading deviations from the reference path) to generate the immediate control action instead of a sequence of optimal or sub-optimal control actions within a finite horizon. In addition, state and control constraints are often ignored. Therefore, it may easily result in abrupt steering actions when vehicles deviate far from the reference path or negotiate a tight turn. Some researchers utilizes the gain-scheduling or variable structure control approaches to avoid abrupt control actions to achieve graceful motions at the expense of reducing tracking accuracy or error convergent speed [6]. Based on the comparison of a variety of path tracking controllers, [7] concluded that path tracking control performance is strongly dependent on both vehicle dynamics and smoothness of the reference path. Essentially, most of these kinematics-based and/or dynamics-based controller primarily focused on eliminating the current cross-track errors instead of taking advantage of the predictive information ahead to integrally optimize a sequence of control actions and its corresponding trajectory, which smoothly regulates the vehicle from the current state onto the sampling states aligned with the reference path ahead. There exists a large amount of research on integrated planning and control approaches for AGVs by applying optimization techniques. One of the most attractive methods is the Model Predictive Control (MPC), which is capable of formulating the vehicle navigation problem into a finite-horizon constrained optimization control problem [8]-[10]. MPC approach uses the vehicle kinematic or dynamic model to predict its future state evolution based on the current measured states. In each control cycle it generates a sequence of control actions, which minimizes a specific objective function within a finite horizon and satisfies the control constraints as well. Then, the first control action is issued to be executed by the low-level actuator. The process is repeated at subsequent time steps. The MPC scheme has the capabilities to systematically deal with system state and control constraints. However, it often assumes the reference path is known and the speed is constant over a short-term finite horizon ahead at each time. When vehicles drive either in on-road or off-road dynamic environments, due to the existence of unexpected obstacles and localization errors, the collision-free assumption of the reference path may be impractical. Solving the optimization problem via MPC scheme may involve non-convex constraints when obstacles are considered. In this case, computational burden and limited on-board computational resources may become a barrier preventing MPC approaches from generating a collision-free and feasible trajectory in real time. To deal with obstacle avoidance and achieve safe and graceful motions along the reference route, we introduce a computationally efficient local trajectory planner between the reference path and the path following controller based on a hierarchical framework. To generate a sufficiently long, collision-free and curvature-continuous trajectory in real-time, the planner is required to consider the reference route and surrounding environmental information from on-board perceptual system, as well as system model and constraints. To some extent, the local trajectory planner performs the function of bridging the gap between high-level rough reference path planning and low-level tracking control. In addition, it enables the vehicle to handle dynamic environments deliberatively and reactively. In addition, corresponding control inputs of the planned trajectory could be used as feedforward control commands by the low-level tracking controller and allow the feedback controller to focus on handling model uncertainties and disturbances. To solve the local trajectory generation problem, several well-known sampling-based motion planning approaches have been extensively studied. Most of them follow a discrete optimization scheme. More specifically, a set of trajectory candidates is generated via forward simulation based on the system model. Then a best trajectory is selected according to an objective function. This sampling-based motion planning scheme can be roughly classified into two categories, one is control space sampling-based method and the other is state space sampling-based method [11]. The former scheme discretizes the control input space (such as constant-curvature arcs [12], clothoids [13], or concatenation of these short-term motions [14]) to generate a set of trajectory candidates via numerical forward integration of differential equations which governs vehicle kinematics or dynamics [15]. Therefore, the generated trajectory candidates are inherently drivable. Due to its simplicity and computational efficiency, the scheme has been widely applied for the local navigation purpose, especially suitable for finding a collision-free path in the far less constrained environment. Based on the symmetric nature of mechanical system, some researchers generate a motion primitive library offline in the body-centered coordinate and use them online via ration and translation [16]. Nonetheless, since the motion primitives are generated by discretizing the control input space, the motion primitives are often not well-separated. A large amount of computational resource will be consumed on exhaustive collision-test and evaluation process. By contrast, instead of sampling discrete control inputs, the state space sampling-based motion planning scheme sample a set of terminal states by using the information of guidance path and environments. It not only considers the position constraints, but also accounts for heading and curvature states constraints imposed by the reference path. To be aligned with the reference path and obtain a collision-free and relatively smooth trajectory, a set of terminal states are sampled laterally offset along the reference path. Several approaches have been proposed to generate trajectories, which connect the vehicle current state with the terminal states aligned with the reference path. Based on cubic Bézier curves, [17] developed an efficient and analytical path smoothing algorithm to generate continuous-curvature path, which considers an upper-bound curvature constraint. Regarding the reference path as a baseline, [18] introduced a geometric method to generate multiple path candidates. The baseline is required to be smooth enough to ensure the smoothness of generated candidates. Instead of using geometric methods, [19] and [20] proposed local dynamically-feasible trajectory planners involving both close-loop control laws (kinematic-based nonlinear control law and pure pursuit control law, respectively) and system, state and control constraints, regardless of the smoothness of the baseline. [21] presented a model predictive trajectory generation scheme, which transforms the local trajectory generation problem into a two-point boundary value problem (BVP), subject to high-fidelity vehicle dynamic constraints. Due to use of the numerical solving method, it achieves a high degree of efficiency and generality. The low-level controller applies an open-loop control strategy for tracking control. The remainder of the paper is organized as follows: in Section II we introduce the structure of the proposed framework. Then, Trajectory generation method and low-level path tracking controller are described in detail in Section III and Section IV respectively. Section V presents the simulation results. Followed by concluding remarks and future work in Section VI.


بخشی از مقاله انگلیسی:

1. Introduction 

The accounting is normally defined as a process of identifying, measuring, recording, classifying and summarizing business transactions which make it possible to achieve its major goal of financial reporting to the stakeholders for decision making. In the context of present criticism on accounting the financial reporting on the affairs of an entity have a very special meaning. The accounting testifies the correctness and fairness of business transactions to the parties to whom these are related. The criticism that the accounting is a tool in the hand of management for misreporting has snatched its good name. Especially in view of the belief of critics of companies that the giant companies are striving in a “silent takeover” of the world. (Micklethwait & Wooddridge, 2003) it became more important to see that whether accounting is fulfilling its most important duty i.e. financial reporting. Unfortunately this is not being done. Earning management is a worst example of this undesirable situation. Even with in the framework of GAAP or International Accounting and Reporting Standards the management with the help of Accountants often manipulates accounting information to deceive other stake holders to meet its dishonest objectives. Earning management occurs when managers use judgment in financial reporting and in structural transactions to alter financial reports to either mislead some stakeholders about underlying performance of the company, or to influence contractual outcome that depend on reported accounting numbers.” (Giroux, 2004) Testifying the correctness and fairness of business transactions is the actual and true spirit at the backdrop of financial reporting. If the financial reports are not in the shape to testify the correctness and fairness of business transactions to its stakeholders than it deny the most important role of accounting of financial reporting. So actually it is the “Principle of Testifying” which regulates the most important function of accounting of financial reporting. However, the present accounting discipline is not fulfilling its obligation. In his article “How the U.S. Accounting Profession Got Where It Is Today”, Stephen A. Zeff (2003) has taken a good stock of journey of accounting profession and its present status in the United States of America. He states: “At the same time as audit partners were given these perverse incentives by their firm’s top management, their clients were becoming ever more driven by their own set of perverse incentives; bonuses based on earnings, and stock options with values linked to the price of the company’s stock (and therefore, it was believed, to earnings). To maximize their mounting compensation, CEOs began to take every advantage of the subjective judgments implicit in accounting choices, thus placing immense pressure on audit engagement partners-themselves under pressure to keep clients content- to accede to accounting practices arguably beyond the realm of acceptability.” This situation is both against principles of “Amanah” (Amer, 2007) and Principle of “Shahadat” (Testimony) which we are discussing here. Actually “Evidence is found that the enforcement o f the “true and fair view” principle is intrinsically flawed when the accountability and the overall corporate governance systems do not work properly” (Melis, 2005).In nut shell there is a need to strength the important role of accounting of Amanah and Shahadat (Testimony). The accounting is oftenly called language of business which provides useful information for decision making. However, these information should be correct and reliable. This has special significance for external parties. As such the preparer i.e. the accountant play a key role for ensuring the quality accounting information. The accountant plays the key role in preparation of financial reporting. Laureen A. Maines and James M. Wahlen in their article “The Nature of Accounting Information Reliability: Inferences from Archival and Experimental Research” (2006) rightly states: “Finally, a significant body of research focuses on users’ reactions to accounting information reliability. This literature generally finds that users are sensitive to differences in the reliability of accounting information and factors that impair reliability. Experimental research, however, documents that even expert users can be influenced by preparers’ choices that weaken reliability. The inclusion of ethics in the accounting education curriculum or code of ethics of professional bodies is not the exact answer as its lack a binding force. As the author suggested in his paper “Development of Islamic Accounting Theory— Principle Of Amanah And Accountant As Ameen” (2007) under the circumstances the best solution to the problems inherited in conventional accounting is to lay down a foundation for a new accounting theory, based on Divine Guidance i.e. teachings of Qur’an and Sunnah of Prophet (Salla Allahu’alaihi wa sallam). Marshall A. Geiger and Porcher L. Taylor III in their article “CEO and CFO Certifications of Financial Information” took a good stock of role of CEO and CFO of public companies in the backdrop of Sarbanes-Oxley Act (SOA). While emphasizing the of spirit behind such certifications in their concluding remarks states: “At the heart of this series of certification requirements is CEO/CFO personal oversight and responsibility for the content and quality of financial information, and increased involvement with internal control. Although these new requirements have the ability to significantly improve financial reporting and disclosure, only long-run adherence to the spirit as well as the letter of the requirements will effectively increase the actual level of reporting accuracy and transparency of public companies in the U.S.” Laureen A. Maines and James M. Wahlen recommend that “Finally, we support research that focuses on preparers because of their central role in the financial reporting process.”(2006) The Quran and Sunah is a main source of such type of research. The Principle of Shahadat (Testimony), based on Islamic concept of testifying, can play a key role for ensuring “true and fair view” of business and reliability of accounting information. In the coming discussion we will briefly see that what this principle is and how it can be a vital component of accounting theory.


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1. Introduction

Chronic low back pain (LBP) is a common cause of work disability and as such is associated with elevated health care costs [1]. More than 80% of people experience an acute episode of LBP sometime during their lives [2], of which 5% develop chronicity [3]. Core stability training is by far one of the most commonly used rehabilitation strategies for improving lumbopelvic-hip control and the dynamic stability of the lumbar spine in people with chronic LBP [4]. Traditional core stability exercises on a stable surface were found to be less effective in inducing high core muscle activity when compared with core stability exercises performed with an instability device such as the TRX suspension straps [5]. Although the core muscle activity was higher when exercising with the labile suspension straps, the spine compressive load was not high [6, 7]. Therefore, TRX suspension training might be particularly suitable for rehabilitating patients with chronic LBP. However, among the large variety of TRX suspension workouts [8], which postures are most suitable for individuals with chronic LBP has yet to be determined. There is only one study that has compared the core muscle activity during four different TRX workouts (hamstring curl, hip abduction in plank, chest press, and 45-degree row) in a group of young, healthy individuals (without LBP). The research team found that hip abduction in plank induced the greatest abdominal muscle activity, whereas the hamstring curl induced the greatest paraspinal muscle activity as measured by the surface electromyography (EMG) [9]. In this study, we examined the core muscle activity during the four aforementioned TRX workouts exclusively in individuals with chronic LBP using surface EMG as it can assess muscle activity directly [9]. We hypothesized that different TRX suspension workouts activate the core muscles differentially in people with chronic LBP. Kinesiology taping (KT) is a relatively new method that has been used in the clinical management of LBP. The tape, which is elastic, porous, and adhesive, can be applied easily to the low back region and does not restrict joint mobility during exercises [10]. Although the effects of KT in clinical studies are controversial [11–14], some beneficial effects of KT have been reported, such as the normalization of muscular function, the correction of possible joint misalignment [11, 12], and enhanced neuromuscular performance [13]. Hence, we postulated that KT might be an ideal adjunct to TRX training to activate the core muscles in people with chronic LBP. To date, no study has examined the acute effects of KT on core muscle activity during the performance of various TRX suspension workouts in individuals with long-term LBP. The aim of this study was to determine the influence of KT and different TRX suspension workouts, and their interactions, on the amplitude of EMG activity in the core muscles among people with chronic LBP.

2. Materials and Methods

This was an experimental study during which each participant underwent four TRX suspension workouts/positions (hamstring curl in supine lying with hips lifted, hip abduction in prone plank, chest press, and 45-degree row in standing inclined) and two taping conditions (with and without KT applied to the low back). In each TRX position and taping condition combination, the core muscles’ activity was measured using surface EMG.The sequence of TRX workouts was randomized to avoid order effect. The participants were recruited from the university via convenience sampling. The inclusion criteria were to have chronic LBP, defined as a persisting or periodic pain in the low back region with a duration of six months or longer [15], be between 18 and 30 years old, and have no previous experience in TRX suspension training. The exclusion criteria were to have neurological deficits, spinal structural deformities, genetic spinal disorders, previous spinal surgery, recent spinal or peripheral injuries (e.g., ligament sprains), allergy to KT, or regular consumption of analgesics, or receive active physiotherapy treatments. The study was approved by the Human Research Ethics Committee of the administering university. All of the participants who volunteered to participate in the study were first screened by a physiotherapist and a trained assistant to ensure that the above criteria were met. In addition, all of the experimental procedures and assessment methods were fully explained to each participant before written informed consent was obtained. All of the procedures were performed in accordance with the Declaration of Helsinki. Demographic information was obtained by interviewing the participants. Body height and weight were measured. Moreover, the participants were asked to quantify their LBP intensity (no pain = 0; worst pain = 10) by using the visual analog scale (VAS) [16]. The self-administered 24- item Roland-Morris Disability Questionnaire (RDQ) was also used to assess physical disability due to LBP (0 = no disability; 24 = maximum disability) [17]. The suspension device, TRX Home Suspension Training Kit (Fitness Anywhere LLC, San Francisco, USA), comprised an adjustable nylon cable with handle straps and foot cradles at both ends that was anchored to the door via a door anchor. The standardized procedures for using the TRX suspension device to perform the four TRX suspension workouts are well described in the TRX user’s guide [8]. These four positions were selected for the high activation of core muscles reported in the literature [5, 9]. Body positioning and any adverse effects (e.g., increased in LBP) during the suspension workouts were closely monitored by the research personnel. Bipolar surface EMG electrodes (EMG sensor SX230- 1000, Biometrics, Newport, UK) were used to detect muscle activity among the four major core muscles—transversus abdominis/internal oblique (TrAIO), rectus abdominis (RA), external oblique (EO), and superficial lumbar multifidus (LMF)—on the right side of the body during the TRX suspension exercises. Active electrode placements on the skin were identified following the recommendations of Marshall and Murphy [18] and Barbero et al. [19] and prepared by shaving and cleansing using alcohol swabs to reduce skin impedance. In brief, the positions of the active electrodes were summarized as follows: TrAIO—2 cm inferior and medial to the anterior superior iliac spine; RA—3 cm superior to the umbilicus and 2 cm lateral to the midline; EO— just above the TrAIO electrode site, in direct line with the umbilicus [18]; and LMF—lateral to the midline at the levels of L2 to L4 [19]. The orientation of the active electrodes was parallel to the muscle fibers for optimal signal recording [9]. The reference electrode (R506, Biometrics, Newport, UK) was placed on the ipsilateral tibial tuberosity. Adhesive tapes were applied to ensure all the EMG electrodes were in firm contact with the skin. The interelectrode distance of the EMG active electrodes was fixed at 1 cm.The EMG signal was sampled at 1000 Hz and amplified by a gain factor of 1000. Other parameters included an input impedance of >1015 Ω, common mode rejection ratio of >96 dB, noise of <5 𝜇V, and bandwidth of 20–460 Hz [20]. All of the EMG electrodes and cables were connected to the DataLOG (Biometrics, Newport, UK), which was securely attached to the participant’s waist during the TRX workouts to minimize artifacts. The DataLOG used both a highpass filter (20 Hz) to remove DC offsets due to membrane potential and a low-pass filter for frequencies above 450 Hz. It also stored EMG data for offline analysis [20]. The EMG signals of each core muscle were postprocessed using the Biometrics EMG analysis software for DataLOG version 8.51 (Newport, UK). The root-mean-square value of the EMG signals (EMGrms) obtained from each core muscle was calculated. Before the TRX suspension workouts, EMG data were collected using two five-second maximal voluntary isometric contraction (MVIC) trials against manual resistance for each of the four core muscles with a one-minute, between-trial rest period. Details for applying the manual resistance have been described in Mok et al. [9] and Escamilla et al. [21]. The average EMGrms value during the middle three-second window of each trial was chosen as the representative MVIC value. The MVIC value of each core muscle was recorded for later data normalization [9]. During the TRX-EMG measurement, the participants were required to maintain each of the four TRX positions for five seconds while the EMG activity of the core muscles was being recorded. The RMS of the EMG activity of each core muscle was computed during a middle three-second period during which the participant held his or her position. Two trials were performed for each of the four testing conditions with a one-minute break between trials. The average EMGrms value of two repetitions of each TRX suspension position was normalized against the RMS value of the MVIC of each core muscle, and thus the outcome was expressed as a percentage of MVIC (%MVIC). %MVIC was selected as the major outcome measure because the test-retest reliability was good (ICC = 0.64) [9]. Upon completion of the four TRX suspension workouts and simultaneous EMG recordings, elastic kinesiology taping (k tape, biviax GmbH & Co. KG, Dortmund, Germany) was applied to the low back region. The EMG electrodes were in firm contact with the skin all the time as the KT tapes were applied on top of the adhesive tapes. Each participant received a standardized kinesiology taping application with four I-strips being placed at about 25% tension overlapping in a star shape over the point of maximum pain in the lumbar region [10]. After fixing the tape, all of the above TRX-EMG measurement procedures were repeated. The %MVIC values of the four core muscles (with taping applied) were calculated and used for analysis. Our statistical analysis was performed using IBM SPSS 20.0 software (IBM, Armonk, NY). The significance level was set at 0.05. A two-way repeated-measures ANOVA (withinsubject factors: TRX position and taping condition) was used to compare the normalized EMGrms data (%MVIC) across the different conditions. The Greenhouse-Geisser epsilon adjustment was used if the sphericity assumption was violated. A post hoc paired 𝑡-test with Bonferroni adjustment was performed if any overall significant results were obtained for the normalized EMGrms data. The effect size (partial etasquared, denoted as partial 𝜂2 ) was also reported—values of 0.14, 0.06, and 0.01 represented large, medium, and small effect sizes, respectively [22].


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ABSTRACT

International Journal of Exercise Science 8(3): 224-233, 2015. Because of its proximity to daily activities functional training becomes more important for older adults. Sling training, a form of functional training, was primarily developed for therapy and rehabilitation. Due to its effects (core muscle activation, strength and balance improvements), sling training may be relevant for older adults. However, to our knowledge no recent sling training program for healthy older adults included a detailed training control which is indeed an essential component in designing and implementing this type of training to reach positive effects. The purpose of this study was to develop a TRX Suspension Training for healthy older adults (TRX-OldAge) and to evaluate its feasibility. Eleven participants finished the 12 week intervention study. All participants trained in the TRX-OldAge whole-body workout which consists of seven exercises including 3-4 progressively advancing stages of difficulty for every exercise. At each stage, intensity could be increased through changes in position. Feasibility data was evaluated in terms of training compliance and a self-developed questionnaire for rating TRX-OldAge. The training compliance was 85 %. After study period, 91 % of the participants were motivated to continue with the program. The training intensity, duration and frequency were rated as optimal. All participants noted positive effects whereas strength gains were the most. On the basis of the detailed information about training control, TRX-OldAge can be individually adapted for each older adult appropriate to its precondition, demands and preference.

INTRODUCTION

The aging process of skeletal muscles is characterized by a reduced number of motor units, muscle fibers and size of type 2 fibers that lead to a loss of muscular strength and power (32). Furthermore, deteriorated proprioception (14, 1) and reaction time (6) were observed with increasing age. These age-related changes result in strength, balance, and mobility declines (13, 7, 8, 3, 2), which could induce falls or a loss of independence (28, 18). It is recommended for older adults to perform regular physical activity to avoid functional limitations (22). Beyond that, exercise intervention studies have demonstrated positive effects on strength, balance, and functional performance for older adults (10, 17, 29). Traditional strength training with weight machines for older adults has been shown to increase muscular strength (29), balance performance if lower limb muscles were trained (17), and functional tasks (10). In past years, sport science has tended to focus on functional strength training for older adults, because it is geared to daily life movements (performing complex movements with own body weight). Compared to traditional resistance training, previous studies showed a similar one repetition maximum (1RM) increase (29, 19) and a significant improvement in the sit-tostand test (19) through functional resistance training, whereas the weight machine group did not change significantly. For maximal walking speed, a significant enhancement was observed within the functional strength training but not within the traditional resistance training group (29). During a reaction task, older adults participating in functional resistance training significantly enhanced their movement time whereas training with weight machines could not achieve this result (33). Strength improvements from traditional resistance training alone and with additional functional (strengthening) exercises are similar (11). However, compared to traditional strength training alone, timed performance of functional abilities like chair rising or stair climbing (20) and balance (5) only changed with additional functional exercises during strength training. Core stability training is a sort of training that combines both functional and strength components. By strengthening core muscles an optimal load transmission from upper to lower body can be realized (34). This can result in better core stability and balance. Because of these effects, functional core stability training programs were conducted in previous intervention studies for older adults (12, 9). One possible core stability program is called sling training. Previous studies focusing on patients with low back pain indicated an increased trunk muscle activation of transversus abdominis, internal oblique, rectus abdominis, multifidi and erector spinae during exercises with a sling trainer (15, 25). In studies with younger adults, both improvements in muscular strength (4, 24) and balance (16, 23) were observed. In regard to older adults, however, there is less evidence from intervention studies implementing sling training. The existent studies with older participants examined osteoporosis and knee osteoarthritis patients (26, 27, 31). Based on the positive effects of sling training on balance and strength parameters in younger adults and patients, this kind of training may be suitable for healthy older adults. However, to our knowledge no sling training program for this target group exists. Therefore the purpose of this study was to develop a detailed exercise prescription for a wholebody sling training program for healthy older adults and to analyze its feasibility. This pilot study provides information about feasibility and practicability of the TRX Suspension Training program developed for older adults (TRX-OldAge).

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