孟加拉国库克斯巴扎(Cox's Bazar)和兰加马蒂(Rangamati)地区森林区和采伐区土壤属性比较

比较了天然林和森林采伐区土壤理化性质,评价了森林采伐对土壤的影响。采集了自然林和邻近的采伐林地三个土层（表层、中层和底层）土壤,对其属性进行了调查。森林土壤颗粒大小分布无显著变化。森林表层土和中层土体积密度存在显著差异。林地内表层土和中层土壤pH、表层土有机质和中层土有效磷均显著高于采伐林地的值。两块林地内可交换Na＋和阳离子交换能力没有变化。这些结果表明,两块林地内表层和亚表层土壤变化较明显。森林采伐降低土壤理化性质。     

Using 137Cs and 210Pbex measurements to explore the effectiveness of soil conservation measures in semi-arid lands: a case study in the Kouhin region of Iran

Journal of Soils and Sediments - One of the most fragile agro-ecosystems in Iran is represented by dry farming lands on steep hillslopes that occupy ca. 54% of the national agricultural lands....     

First report on molecular surveillance based on duplex detection of Anaplasma marginale and Theileria annulata in dairy cattle from Punjab,Pakistan

The study aimed to investigate if vegetable-based high-energy mash diets supplemented with NaHCO₃, l-arginine?+?vitamin C, and vegetable oils were effective against tachycardia and polycythemia in the broiler chicken. A total of 256 Ross-308 day-old male broiler chicks were randomly distributed into eight dietary treatment groups in a three-way ANOVA with 2?×?2?×?2 factorial arrangement (three factors, i.e., NaHCO₃, l-arginine?+?vitamin C, and vegetable oil each with two levels, e.g., 0 and 0.1% of NaHCO₃ and l-arginine?+?vitamin C; 3 and 4% of vegetable oil supplemented with basal diet) for a period of 35 days. Iso-caloric and iso-nitrogenous diets were formulated and supplied ad libitum. The final live weight (FLW), average daily feed intake (ADFI), average daily gain (ADG), feed efficiency (FE), carcass traits, cardio-pulmonary morphometry, total protein (TP), hemoglobin (Hb), triiodothyronine (T₃), incidence of tachycardia, and polycythemia were examined. Supplementation of NaHCO₃ increased 2.2% ADFI, 5.5% FE, and 23.2% TP. The l-arginine?+?vitamin C increased 2.4% FLW and decreased 1.9% heart rate. Vegetable oil increased 1.3% ADFI, 4.2% ADG, 8.6% FE, 23.1% Hb, and 15.5% PCV. The NaHCO₃, l-arginine?+?vitamin C, and vegetable oil additively interacted to increase 31.5% T₃ at the expense of 21.1% of the weight of the right ventricle (RV). The RV:TV, carcass traits, and hemato-biochemical indices remained within normal range irrespective of the levels of the supplementations of the test ingredients. It was concluded that vegetable-based high-energy mash diets were not susceptible to tachycardia and polycythemia. The addition of NaHCO₃ and l-arginine?+?vitamin C ameliorated the propensity of tachycardia and polycythemia without deteriorating performance, carcass traits, and hemato-biochemical indices of the broiler chicken in a dose-dependent manner.

     

炎热季节不同代谢能和粗蛋白水平对肉鸡生产性能的影响

试验旨在研究炎热夏季不同代谢能（ME）和粗蛋白（CP）水平对肉鸡生产性能的影响。选择1日龄宝星肉仔鸡600只（公母比例为1：1）,并平均分配到30个试验组（公母比例为1：1）。试验采用2x3因素设计,代谢能水平分别为12．13和12．55MJ·k^-1,粗蛋白水平分别为190、210和230g·kg^-1共6个处理。低蛋白饲粮补充晶体氨基酸以满足其必需氨基酸的需求。每个处理设5个重复,试验期为1～28日龄。试验结束时,从每个重复中随机选择两只鸡测定屠体重、胸肌重、腹脂、肝和胃的重量。随着饲粮ME水平的升高,体重、腹脂和肝脏重量、屠体蛋白质和脂肪含量均显著升高：然而屠体干物质含量降低。饲粮CP对体重、饲料增重比、屠体重、肉中干物质和蛋白含量有二次效应。随着饲粮CP水平的升高,胸肌重和肉中脂肪含量线性升高。低CP（190g·kg^-1）高ME（12．55MJ·kg^-1）饲粮提高体重、采食量、屠体重,并改善饲料增重比;中CP（210g·kg^-1）、低ME（12．13MJ·kg^-1）组饲料增重比最低。高CP、高ME组屠体蛋白质和脂肪含量升高,然而高CP、低ME组肉中干物质含量高。结果表明了饲粮蛋白质和能量之间的相互联系,在不考虑其他因素的情况下不能预测其最适宜水平。总之,在32～39℃环境条件下低CP高ME饲粮能提高肉仔鸡的总体生产性能。     

Effect of coir fiber content and compatibilizer on the properties of unidirectional coir fiber/polypropylene composites

The main objective of this research was to study the effect of fiber content variation and stearic acid (SA) treatment on the fundamental properties of unidirectional coir fiber (CF) reinforced polypropylene (PP) composites. Several percentages of filler contents were used (10–40 wt %) in order to gain insights into the effect of filler content on the properties of the composites. Coir/PP composites were fabricated by compression molding, and the properties of composites were studied by physico-mechanical and thermal properties. The results from mechanical properties such as tensile strength (TS), tensile modulus (TM) and impact strength (IS) of the CF/PP composites were found to be increased with increasing fiber content, reached an optimum and thereafter decreased with further increase in fiber content. Treatment of the coir with SA as the coupling agent enhanced the mechanical properties, crystallization temperature and crystallinity of virgin PP and water desorption of the resulting composites, resulting from the improved adhesion between the CF and PP matrix. Scanning electron micrographs (SEM) of the tensile fractured samples showed improved adhesion between fiber and matrix upon treatment with SA. Interfacial shear strength (IFSS) of the composites was measured by single fiber fragmentation test (SFFT).     

Genetic diversity and yield performance among T. Aman rice (Oryza sativa L.) landraces in Barishal region of Bangladesh

Journal of Crop Science and Biotechnology - Understanding genetic diversity of rice helps to improve its yield. Although many landraces of rice are grown in the coastal area of Bangladesh, their...     

Effects of urease and nitrification inhibitors on the efficient use of urea for pastoral systems

Abstract

The humic substances contained in an animal organic waste were extracted and the total extract separated into three humic fractions with different molecular weights (low, F₁ <10³; medium, F₂, with molecular weights ranging from 10³ to 10⁴; and high, F₃ >10⁴). The C content was highest in F₂, the same fraction also showing the lowest N content. The molecular weight of the humic fractions influenced the electrical conductivity, the highest molecular weight resulting in the lowest degree of electrical conductivity. Membrane-controlled ultrafiltra-tion (the method used to separate the various fractions from the whole extract) was also suitable for purifying such enzymes as phosphatase and β-glucosidase: the total activity obtained from the three fractions was considerably greater than that determined in the whole extract, Pyrolysis-gas chromatography (Py-GC) applied to the whole extract and humic fractions showed that in the F₃ fraction (highest molecular weight) benzene was the major fragment while furfural was the major fragment of F₁ (lowest molecular weight). For this reason, the humification index benzene/toluene indicates that the fraction with the highest molecular weight was the most humified while the furfural/pyrrole ratio indicates that the fraction with the lowest molecular weight was the most degradable. The whole extract and the fraction F₁ had a negative effect on seed germination when the concentration was equivalent to 100 mg kg^?1 of C, while the germination index was higher than that of the control when only 10 mg kg^?1 were used. The F₂ fraction had a positive effect on germination regardless of the concentration used. When 10 mg kg^?1 of C of the humic substances studied were added to the nutrient solution for growth experiments with maize plants, F₃ led to increases in root weight and F₂ led to increases in shoot weight. An inhibitor effect was observed for fraction F₁.     

Cell type-specific loss of BDNF signaling mimics optogenetic control of cocaine reward

The nucleus accumbens is a key mediator of cocaine reward, but the distinct roles of the two subpopulations of nucleus accumbens projection neurons, those expressing dopamine D1 versus D2 receptors, are poorly understood. We show that deletion of TrkB, the brain-derived neurotrophic factor (BDNF) receptor, selectively from D1+ or D2+ neurons oppositely affects cocaine reward. Because loss of TrkB in D2+ neurons increases their neuronal excitability, we next used optogenetic tools to control selectively the firing rate of D1+ and D2+ nucleus accumbens neurons and studied consequent effects on cocaine reward. Activation of D2+ neurons, mimicking the loss of TrkB, suppresses cocaine reward, with opposite effects induced by activation of D1+ neurons. These results provide insight into the molecular control of D1+ and D2+ neuronal activity as well as the circuit-level contribution of these cell types to cocaine reward.     

Factors affecting shoot and root apical meristem tissue culture of Thai supersweet corn (Zea mays var. rugosa)

During last recent years, in vitro propagation technic is widely used to produce plants with desirable traits. This experiment was conducted to produce an ideal protocol for in vitro propagation of Thai supersweet corn by using shoot apical meristem (SAM) and root apical meristem (RAM) as explants. Four-day-old germinating seedlings were used as the experimental materials on culture media supplemented with a range of auxin, kinetin, and carbohydrates. The primary establishment for SAM showed the highest percentage of survival (80%) while RAM showed the highest survival (67%) and in Murashige and Skoog (MS) media supplemented. Upon acclimatization, regenerated plantlets from shoot showed the highest survival rate (12%) with the production of 21 plantlets; however, the survival rate of plantlets from root was only 20% with the production of 9 plantlets. The efficient and economic protocol that is produced in this study can be applied as an alternative to conventional propagation method for the large-scale production of Thai supersweet corn throughout the year.