Evapotranspiration is an important component in many hydrological, ecological and agricultural studies. There are many available direct and indirect methods to determine the evapotranspiration rate. In this study, alternative model based on multilayer Artificial Neural Network (ANN) using the backpropagation algorithm was proposed to estimate evapotranspiration as referred to pan evaporation. The meteorological data used in this study were obtained from Al-Zahra and Al-Zawia stations which located on the coastal area of western Libya lie. The input data were consisted of mean temperature, mean relative humidity and mean of actual sunshine hours of consecutive years (1995, 1996, 1997 and 1999). The performance of the ANN model was evaluated against a set of data that never seen by the model during the training phase. The evaluation of ANN model was also performed against Blaney and Criddle, Radiation and modified Penman methods. The results showed that ANN forecasts were superior to the ones obtained by Blaney and Criddle and Radiation methods. Due to its little input data, ANN is considered to be more efficient as compared with the modified Penman method. However, this application of ANN as a fitting tool should be useful in evapotranspiration modeling. Keywords: Evapotranspiration Pan evaporation, Artificial neural networks, Backpropagation algorithm.
Ahmed Ibrahim Ekhmaj(1-2012)

مجلة العلوم الأساسية والتطبيقية 2007 وزن الميلاد والوزن عند عمر 70 يوم ووزن الفطام وما بعد الفطام في الضأن البربري الليبي عبدالكريم أحتاش و عياد مجيد و محمد صنام و نورالدين الجعودي الملخص: تضمنت الدراسة سجلات لمعدلات النمو لعدد 514 رأساً من حملان الضأن البربري الليبي التابعة لمحطة بئر الغنم البحثية (مركز بحوث الثروة الحيوانية). تهدف هذه الدراسة إلى تقييم معدلات النمو في حملان البربري الليبي من خلال الوزن عند الميلاد والوزن عند عمر 70 يوماً والوزن عند الفطام والوزن الشهري ما بعد الفطام لمدة ثلاثة شهور، بالاضافة إلى دراسة تأثير جنس الحيوان في هذه الصفات. بينت نتائج الدراسة أن متوسط الوزن عند الميلاد والوزن عند عمر 70 يوم والوزن عند الفطام والأوزان الشهرية ما بعد الفطام لحملان البربري الليبي كان 3.17 كجم و 15.99 كجم و 23.48 كجم و 25.71 كجم و 28.86 كجم و 34.28 كجم على التوالي. وكان معدل الزيادة اليومية قبل الفطام لحملان البربري الليبي 169 جم/ اليوم. وكان تأثير جنس الحيوان معنويا على جميع الصفات المدروسة، حيث تفوقت الحملان الذكور على الإناث في وزن الميلاد بـ 0.120 كجم والوزن عند عمر 70 يوم بـ 1.40 كجم والوزن عند الفطام بـ 2.700 كجم. arabic 153 English 2
عبدالكريم امحمد احمد احتاش, عياد مجيد, محمد صنام, نورالدين الجعودي(10-2007)

Soil databases are very important for assessing ecosystem services at different administrative levels (e.g., state, region etc.). Soil databases provide information about numerous soil properties, including soil inorganic carbon (SIC), which is a naturally occurring liming material that regulates soil pH and performs other key functions related to all four recognized ecosystem services (e.g., provisioning, regulating, cultural and supporting services). However, the ecosystem services value, or “true value,” of SIC is not recognized in the current land market. In this case, a negative externality arises because SIC with a positive value has zero market price, resulting in the market failure and the inefficient use of land. One potential method to assess the value of SIC is by determining its replacement cost based on the price of commercial limestone that would be required to amend soil. The objective of this study is to assess SIC replacement cost value in the contiguous United States (U.S.) by depth (0–20, 20–100, 100–200 cm) and considering different spatial aggregation levels (i.e., state, region, land resource region (LRR) using the State Soil Geographic (STATSGO) soil database. A replacement cost value of SIC was determined based on an average price of limestone in 2014 ($10.42 per U.S. ton). Within the contiguous U.S., the total replacement cost value of SIC in the upper two meters of soil is between $2.16T (i.e., 2.16 trillion U.S. dollars, where T = trillion = 1012) and $8.97T. States with the highest midpoint total value of SIC were: (1) Texas ($1.84T), (2) New Mexico ($355B, that is, 355 billion U.S. dollars, where B = billion = 109) and (3) Montana ($325B). When normalized by area, the states with the highest midpoint SIC values were: (1) Texas ($2.78 m−2), (2) Utah ($1.72 m−2) and (3) Minnesota ($1.35 m−2). The highest ranked regions for total SIC value were: (1) South Central ($1.95T), (2) West ($1.23T) and (3) Northern Plains ($1.01T), while the highest ranked regions based on area-normalized SIC value were: (1) South Central ($1.80 m−2), (2) Midwest ($0.82 m−2) and (3) West ($0.63 m−2). For land resource regions (LRR), the rankings were: (1) Western Range and Irrigated Region ($1.10T), (2) Central Great Plains Winter Wheat and Range Region ($926B) and (3) Central Feed Grains and Livestock Region ($635B) based on total SIC value, while the LRR rankings based on area-normalized SIC value were: (1) Southwest Plateaus and Plains Range and Cotton Region ($3.33 m−2), (2) Southwestern Prairies Cotton and Forage Region ($2.83 m−2) and (3) Central Great Plains Winter Wheat and Range Region ($1.59 m−2). Most of the SIC is located within the 100–200 cm depth interval with a midpoint replacement cost value of $2.49T and an area-normalized value of $0.34 m−2. Results from this study provide a link between science-based estimates (e.g., soil order) of SIC replacement costs within the administrative boundaries (e.g., state, region etc.). arabic 19 English 114
Garth Groshans, Elena Mikhailova, Christopher Post, Mark Schlautman, Hamdi Zurqani, Lisha Zhang(12-2018)