نتایج جستجو برای: طبقهبندی jel c01
تعداد نتایج: 27750 فیلتر نتایج به سال:
Agriculrural ecosystems comprise an estimated 113 of the land surface of the earth (Houghton ec al .. 1983) a.nd include some of the mosc productive and carbon-rich soils. As a result they play a significant role in the storage and release of C within the terresrrial carbon cycle. At the same time these ecosystems are higllly impacted through human activities and thus processes determining net ...
گوشدادن به صداها و ارتعاشات تولیدشده ناشی از فعالیت مکانیکی قلب و تفسیر آنها روش متداولی است که در ارزیابی وضعیت سیستم قلبی-عروقی بهکار می رود. از مزایای این روش می توان به آسانی انجام آن، زمان مورد نیاز کم، هزینه پایین و غیرتهاجمیبودن اشاره کرد. اما بهدلیل محدودیتهای شنوایی انسان، ماهیت گذرا و غیرایستان صداهای قلب، و انرژی پایینتر صداهای پاتولوژیک نسبت به صداهای طبیعی یافتن نشانههای بیماری و ت...
a r t i c l e i n f o JEL classification: C53 G17 Keywords: GARCH Higher conditional moments Approximate predictive distributions Value-at-Risk S&P 500 Treasury bill rate Euro–US dollar exchange rate It is widely accepted that some of the most accurate Value-at-Risk (VaR) estimates are based on an appropriately specified GARCH process. But when the forecast horizon is greater than the frequency...
The O-Ring theory is used to analyze the emergence of ̄rms organized as partnerships. The owner-managers of such entrepreneurial ̄rms bene ̄t from ability matching within their production teams. However, they must bear the project risk. Risk-aversion then induces a second-best solution. Integrated ̄rms managed on behalf of riskneutral residual-claimants face information and/or enforcement problem...
در طول دو دهه اخیر مطالعات کاربردی بسیاری برای ارزیابی دلایل ناکارایی در صنایع مختلف از یک روش شبه پارامتری دو مرحلهای موسوم به مدل توبیت استفاده نمودهاند. کاربرد این روش برای نمونههای کوچک به دلیل امکان وجود تورش در نتایج آن، اخیراً مورد انتقاد بوده است. یک روش دو مرحلهای شبه پارامتریک بوتاسترپ شامل دو الگوریتم منفرد و مضاعف را برای حل این مشکل ارائه نمودهاند. این دو الگوریتم، تخمینهای ا...
The characteristics of crude oil and the factors affecting the price of this energy carrier have caused its price forecast to always be considered by researchers, oil market activists, governments and policy makers. Since the price of crude oil is affected by many factors, therefore, continuous studies should be done in this way so that the estimates made over time, the results are more accurat...
many empirical papers have applied a semi-parametric two-stage procedure named tobit model to investigate the sources of inefficiency in different industries over the last two decades. using this approach in small samples has recently been criticized for a possible bias in its results. in very recent papers simar and wilson (2007) have tackled this problem by suggesting an alternative bootstrap...
Background: Allogenic hematopoietic stem cell transplantation (HSCT) is a strategy used for treatment of different malignant diseases. However, success of allo-HSCT can be hampered by graft-versus-host-disease (GVHD). Natural killer (NK) cells may play an important role in activating antigen presenting cells and subsequent activation of T cells. The main purpose of this study was the evaluation...
Bu çalışmada, sol-jel spin kaplama yöntemi kullanılarak mikroskop cam altlıklar üzerine TiO2, TiO2/CoPc ve CoPc filmleri hazırlanmış katkı konsantrasyonunun filmlerin optik yapısal özellikleri etkisi araştırılmıştır. İnce geçirgenliğini ölçmek için 300-1100 nm dalgaboyu aralığında bir spektrofotometre kullanılmıştır. Uv-Vis çalışmaları, B Q bandı absorpsiyon bölgelerine karşılık gelen aralıklar...
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