Inference on the Parameters of the Weibull Distribution Using Records

The Weibull distribution is a very applicable model for the lifetime data. In this paper, we have investigated inference on the parameters of Weibull distribution based on record values. We first propose a simple and exact test and a confidence interval for the shape parameter. Then, in addition to a generalized confidence interval, a generalized test variable is derived for the scale parameter when the shape parameter is unknown. The paper presents a simple and exact joint confidence region as well. %for the scale and shape parameters. In all cases, simulation studies show that the proposed approaches are more satisfactory and reliable than previous methods. All proposed approaches are illustrated using a real example.Comment: Accepted for publication in SOR

Magnetosome vesicles are present before magnetite formation, and MamA is required for their activation

Bacterial magnetosomes are intracellular compartments that house highly ordered magnetite crystals. By using Magnetospirillum sp. AMB-1 as a model system, we show that magnetosome vesicles exist in the absence of magnetite, biomineralization of magnetite proceeds simultaneously in multiple vesicles, and biomineralization proceeds from the same location in each vesicle. The magnetosome-associated protein, MamA, is required for the formation of functional magnetosome vesicles and displays a dynamic subcellular localization throughout the growth cycle of magnetotactic bacteria. Together, these results suggest that the magnetosome precisely coordinates magnetite biomineralization and can serve as a model system for the study of organelle biogenesis in noneukaryotic cells

The review on impact of intellectual capital on financial performance of investment companies accepted in Tehran Stock Exchange Organization (TSEO)

The present period is age of knowledge based economy. By virtue of the existing limitations in tangible sources, today role and importance of intangible sources has been highly improved. According to the attitude based on corporative sources, one of the important sources for enterprises is intellectual capitals, particularly in investment companies that are usually benefitted from less tangible sources. Thus, the present study is intended to examine the impact of intellectual capital on financial performance of investment companies which have been accepted in Tehran Stock Exchange Organization (TSEO) within the studied time period (2006-2010) and the selected sample comprises of 28 investment enterprises. In order to measure intellectual capital, Value- Added Intellectual Capital (VAIC) factor, which had been codified by Palick (2000), was used that is one of the paramount and most valuable evaluation techniques for intellectual capital. The results obtained from testing hypotheses in this study that derived by means of Ordinary Least Squares (OLS) regression suggest that intellectual capital has direct and significant effect on financial performance of investment companies and at the same time there is a direct and significant correlation among intellectual capital and future performance

Solution of the two-dimensional telegraph equation via the local radial basis functions method

In the present study, we utilize the local meshless method for solving second order hyperbolic partial differential equation in two dimensions. First we apply the Crank-Nicolson difference scheme for the time derivative and the local radial basis functions (LRBFs) collocation method for the spatial derivative. The local approach breaks down the problem domain into subdomains and results small matrix system for each data. Some numerical examples are included to verify the computational efficiency of the proposed method.Publisher's Versio

The review on impact of intellectual capital on financial performance of investment companies accepted in Tehran Stock Exchange Organization (TSEO)

The present period is age of knowledge based economy. By virtue of the existing limitations in tangible sources, today role and importance of intangible sources has been highly improved. According to the attitude based on corporative sources, one of the important sources for enterprises is intellectual capitals, particularly in investment companies that are usually benefitted from less tangible sources. Thus, the present study is intended to examine the impact of intellectual capital on financial performance of investment companies which have been accepted in Tehran Stock Exchange Organization (TSEO) within the studied time period (2006-2010) and the selected sample comprises of 28 investment enterprises. In order to measure intellectual capital, Value- Added Intellectual Capital (VAIC) factor, which had been codified by Palick (2000), was used that is one of the paramount and most valuable evaluation techniques for intellectual capital. The results obtained from testing hypotheses in this study that derived by means of Ordinary Least Squares (OLS) regression suggest that intellectual capital has direct and significant effect on financial performance of investment companies and at the same time there is a direct and significant correlation among intellectual capital and future performance

The review on impact of intellectual capital on financial performance of investment companies accepted in Tehran Stock Exchange Organization (TSEO)

The present period is age of knowledge based economy. By virtue of the existing limitations in tangible sources, today role and importance of intangible sources has been highly improved. According to the attitude based on corporative sources, one of the important sources for enterprises is intellectual capitals, particularly in investment companies that are usually benefitted from less tangible sources. Thus, the present study is intended to examine the impact of intellectual capital on financial performance of investment companies which have been accepted in Tehran Stock Exchange Organization (TSEO) within the studied time period (2006-2010) and the selected sample comprises of 28 investment enterprises. In order to measure intellectual capital, Value- Added Intellectual Capital (VAIC) factor, which had been codified by Palick (2000), was used that is one of the paramount and most valuable evaluation techniques for intellectual capital. The results obtained from testing hypotheses in this study that derived by means of Ordinary Least Squares (OLS) regression suggest that intellectual capital has direct and significant effect on financial performance of investment companies and at the same time there is a direct and significant correlation among intellectual capital and future performance

Effects of electrical stimulation of ventral tegmental area on morphine addiction in rat

زمینه و هدف: ناحیه تگمنتوم شکمی VTA= Ventral Tegmental Area در مزنسفال در دو طرف خط وسط و در عمق 9 میلی متری از سطح استخوان پس سری قرار داشته و در مراحل شکل گیری اعتیاد دخالت دارد. در این مطالعه تحریک الکتریکی این ناحیه و تاثیرش بر روند اعتیاد به مورفین مورد بررسی قرار گرفته است. روش مطالعه: در یک مطالعه مداخله ای، خود تزریقی داخل وریدی برای یافتن میزان اعتیاد بکار گرفته شد. 24 رت ویستار به سه گروه sham یا سالین (بدون تحریک و دریافت نرمال سالین)، گروه کنترل یا مورفین (بدون تحریک و دریافت مورفین) و گروهcase یا مورفین + تحریک (تحریک الکتریکی به میزان μA 25=جریان Hz 100=فرکانس و پریود=14/0 میلی ثانیه، پانزده دقیقه قبل از خود تزریقی مورفین و به مدت ده دقیقه) تقسیم شدند. نتایج: فقط در گروه مورفین اعتیاد حاصل شد ولی میزان خود تزریقی مورفین در گروه مورفین + تحریک نسبت به گروه مورفین بسیار کمتر بود که نشان دهنده عدم اعتیاد گروه مورفین + تحریک می باشد. نتیجه گیری: تحریک الکتریکی VTA از افزایش میزان پدال های زده شده جهت دریافت مورفین جلوگیری کرده و بنابراین اثرات پاداشی داشته و موجب آزاد شدن دوپامین در هسته اکومبنس شده است و می توان گفت که اثر تحریکی نرون های دوپامینی بعد از تحریک این ناحیه بیشتر بوده و غلبه بر تحریک نرون های گاباارژیک مهار کننده نرون های دوپامینی و همچنین تحریک ترمینال نرون های اوران تحریکی و یا مهاری به VTA دارد

Exploring appropriate livelihood alternatives for sustainable rangeland management

Rangeland degradation and vulnerability of livelihoods are two major challenges facing pastoralists, rangeland managers and policy-makers in arid and semi-arid areas. There is a need to make holistic informed decisions in order to protect rangelands and sustain livelihoods. Through a comprehensive literature review on rangeland management policies and livelihood strategies of 'rangeland users', it is shown how such policies have affected sustainable rangeland management, how strategies to sustain livelihoods have been incomplete and how there has been a lack of a multi-disciplinary approach in acknowledging them. Accordingly, a set of appropriate livelihood alternatives is introduced and, thenceforth, a framework for their evaluation is developed. Supportive strategies for enhancing resilience are discussed as a research and policy-making gap. In this study, the keys to achieve sustainable livelihoods are acknowledged as 'livelihoods' resilience', where livelihoods need to be supported by access to capital, means of coping with the contexts of vulnerability as well as by enhancing policies, institutions and processes. The paper proposes a set of 'livestock-based livelihoods' regarding 'traditional pastoralism' as well as 'their mitigation and adaptation'. Moreover, their transformation to 'commercial pastoralism', 'resource-based livelihoods', 'alternative livelihoods' and 'migration' strategies is recognised to be employed by rangeland users as useful alternatives in different regions and under future changing conditions including climate change. These strategies embrace thinking on resilience and are supported by strategies that address social and ecological consequences of climate change consisting of mitigation, adaptation and transformation. It is argued that sustainable livelihoods and sustainable rangeland management will be achieved if they are supported by policies that build and facilitate a set of appropriate livelihood alternatives and keep them in a sustainable state rather than being limited to supporting 'vulnerable livelihoods'. Finally, future directions for analysing and policy-making in selecting the best alternative to achieve sustainable livelihoods are indicated