三亚草蓬岭森林公园开发条件分析与规划构想

该文在充分调查三亚草蓬岭森林公园森林旅游资源现状基础上,结合三亚市旅游发展特点,对草蓬岭森林公园开发建设进行了SWOT分析。同时根据公园内森林景观资源特点,提出了公园建设的规划构想。     

Study on burden pile profile prediction model for COREX-3000 melter gasifier

The distribution of reducing gas in melter gasifier of COREX-3000 directly influences gas utilization and burden descent.The charging of burden is a main method of regulating gas flow distribution.In order to reveal the burden distribution process,a mathematical model of forecasting the burden pile profile is established based on the impact position,angle of repose and the mass conservation of burden.The impact position of burden is determined by analyzing the material flow trajectory and force during charging process.Based on the mathematical model,an extended burden pile profile prediction software of COREX-3000 melter gasifier is developed by combining mathematic knowledge and computer technology.Using this software,the burden trajectory,the impact position and the burden pile profile under various operations of the coal-gimbal distributor and the DRI-flap distributor can be easily obtained,which can provide reference data for adjusting the charging operation in practice.     

陕西关中地区城市园林植物抗污能力调查分析

在调查陕西关中重工业区现有园林植物的生长、分布情况的基础上,采用Singh的大气污染忍耐指数并结合主要生理指标和叶片硫含量的测定,全面分析研究了其园林植物抗污染能力.结果表明,月季、垂柳、臭椿这3树种对SO2的抗性和吸收量都较强,可以在以SO2为主的污染区作为基调树种种植;采用Singh的大气污染忍耐指数综合评价树种抗性,大部分树种与污染区现场调查的情况基本一致.综合分析表明,臭椿、大叶黄杨、雪松、银杏、大叶女贞和国槐等6种树木的抗性较强.     

Ethanol augments GABAergic transmission in the central amygdala via CRF1 receptors

The central amygdala (CeA) plays a role in the relationship among stress, corticotropin-releasing factor (CRF), and alcohol abuse. In whole-cell recordings, both CRF and ethanol enhanced gamma-aminobutyric acid-mediated (GABAergic) neurotransmission in CeA neurons from wild-type and CRF2 receptor knockout mice, but not CRF1 receptor knockout mice. CRF1 (but not CRF2) receptor antagonists blocked both CRF and ethanol effects in wild-type mice. These data indicate that CRF1 receptors mediate ethanol enhancement of GABAergic synaptic transmission in the CeA, and they suggest a cellular mechanism underlying involvement of CRF in ethanol's behavioral and motivational effects.     

华重楼组培快繁技术研究

【目的】建立华重楼组培快繁技术体系。【方法】以华重楼幼苗为试材,研究外植体预处理方式 和消毒方法,筛选适宜诱导的外植体,筛选不定芽诱导、增殖以及生根和结鳞茎最佳培养基。【结果】华重楼 外植体先经过 0.5% 多菌灵浸泡 2 h,再利用 75% 乙醇浸泡 45 s 和 0.1% HgCl2 消毒 10 min,污染率最低（1.67%）, 诱导的不定芽长势最好。高 5~10 cm、带根系的华重楼幼苗或去掉茎叶的幼苗是最适外植体,不定芽诱导最佳 培养基为 WPM+2.0 mg/L ZT+0.1 mg/L NAA+30 g/L 蔗糖,诱导率达 98.33%,萌发的新芽生长更快;不定芽增殖 最适培养基为 MS+2.0 mg/L 6-BA+1.0 mg/L IAA+30 g/L 蔗糖,培养 90 d 后增殖系数为 3.75;不定芽生根和结鳞茎 最适培养基为 WPM+2.0 mg/L ZT+0.1 mg/L NAA+30 g/L 蔗糖,生根和结鳞茎率达 96.67%,根系数 3.84 条,根长 4.15 cm,鳞茎直径 0.86 cm。生根苗 3—5 月份移栽到基质为泥炭土︰珍珠岩︰河沙 =2 ∶ 1 ∶ 1 的组合物中成活 率最高,为 30%。【结论】建立了适合华重楼幼苗组培快繁的技术体系,为华重楼的资源保护及规模化生产优 质种苗奠定了基础。     

饲料学课程考核方式改革的研究和实践

本文简要分析了饲料学考核方式的现状和存在的问题,并根据饲料学课程性质,从理论课程和实验课程2个方面对考核方式进行了改革和实践。经实践证明,本次对饲料学考核方式的改革,激发了学生的学习热情和积极性,提高了教学质量,为动物科学专业相关课程考核方式的改革提供借鉴。     

网络涉农舆情收集与预警技术

介绍了互联网涉农舆情收集与预警技术的需求背景和相关技术,对技术之间如何进行联合应用进行了概述,提出了网络涉农舆情收集与预警技术中将来需要不断加强研究的关键技术,并进行了展望。     

广东家庭农场发展现状、问题与对策建议——基于湛江和梅州两地的实地调查

家庭农场是现阶段中国新型农业经营主体,它代表着未来中国农业发展的方向。本文通过对广东湛江和梅州两地的实地调研,发现广东家庭农场的发展普遍呈现出三个特点,即概念界定模糊,名称多样;流转山地多,水田少;单一种植少,种养结合多。家庭农场发展主要面临三个难题,即土地流转难、资金周转难和用工难。针对出现的这些问题,进而提出在全省制定扶持和培育家庭农场的政策文件、建立健全的土地流转机制、制定金融部门支持家庭农场发展的政策和建立完善的农业服务体系等对策建议。     

抗菌肽不同处理方式对虹鳟免疫指标的影响

为明确中国鲎基因工程抗菌肽不同处理方式对虹鳟(Oncorhynchus mykiss)存活率的影响,分别在虹鳟仔鱼和成鱼两个阶段采用浸泡和混合饲料两种方式应用抗菌肽。采集仔鱼全鱼组织,成鱼血清及头肾组织,通过对SOD、ALP、CAT、IL-1β、IFN-γ、TNF-α等免疫相关酶水平及细胞因子表达量变化情况的检测,验证抗菌肽不同处理方式对虹鳟免疫指标的影响。结果发现:应用84 U/mL抗菌肽浸泡虹鳟仔鱼10次,浸泡后第4天,试验组免疫相关酶水平明显高于对照组,其中IL-1β、IFN-γ差异极显著(P<0.01),其他差异显著(P<0.05)。浸泡后第15天,试验组免疫相关酶水平仍高于对照组健康鱼,其中IL-1β、IFN-γ差异极显著(P<0.01),其他差异显著(P<0.05),但对照组发病鱼免疫相关酶水平与试验组相比显著下降,SOD、ALP、IL-1β、IFN-γ均差异极显著(P<0.01),其他差异显著(P<0.05)。试验结束统计仔鱼存活率,试验组存活率高达95.1%,对照组存活率仅为29.9%。成鱼期采用混合饲料和浸泡两种方式应用抗菌肽。结果显示,混合饲料的最适添加量为50 mg/kg饲料,浸泡最佳浓度为84 U/mL,最佳浸泡时间为3 min。研究表明,对不同处理方式进行对比,在仔鱼期进行浸泡对虹鳟免疫指标的影响最为显著。其可能与抗菌肽种类、作用方式及养殖虹鳟疾病暴发特点有关。本研究可以为虹鳟养殖过程中抗菌肽的应用方式提供依据。     

Effect of dietary phosphorus content on milk production and phosphorus excretion in dairy cows

Background

Phosphorus (P) supplementation is costly and can result in excess P excretion. This study investigated the effects of reducing dietary P on milk production and P excretion in dairy cows over a full lactation.

Method

Forty-five multiparous Holstein dairy cows were divided into 15 blocks according to expected calving date and previous milk yield, and assigned randomly to one of the three dietary treatments: 0.37, 0.47, and 0.57% P (DM basis); these P levels represent the NRC recommendations, Chinese recommendations, and the amount of dietary P commonly fed by Chinese dairy farmers, respectively. Average daily feed intake was calculated from monthly data on feed offered and refused. Milk yields of individual cows were recorded weekly, and milk samples were taken for analysis of protein, fat, solids-not-fat, lactose, and somatic cell count. Blood samples were collected on days −6, −3, 0, 3, 6 relative to calving, and then monthly throughout lactation, and analyzed for P and Ca concentrations. Spot samples of feces and urine were collected for 3 consecutive d during weeks 12, 24, and 36, and P concentrations were analyzed. Reproduction and health data were recorded.

Results

Dietary P did not affect dry matter intake or milk yield (P > 0.10). Milk fat content was slightly higher in cows fed 0.37% P than in cows fed 0.47% P (P = 0.05). Serum concentrations of P and Ca did not reflect dietary P content (P > 0.10). Fecal and urinary P both declined linearly (P < 0.05) as dietary P decreased from 0.57 to 0.37%. Fecal P content was 25% less when dietary P was 0.37% compared to 0.57%. Health events and reproductive performance were not associated with dietary P content (P > 0.05).

Conclusions

Lowering dietary P from 0.57 to 0.37% did not negatively affect milk production, but did significantly reduce P excretion into environment.