对北京市公益林市场化经营的思考

北京市的公益林作为传统意义上的公共物品，一直以来由全市各级政府投资建设，成本高，效率低，代价大。因此，提高公益林的经营效率和质量，对于北京市公益林的持续、健康发展至关重要。笔者就如何在北京市公益林的经营中引入市场机制进行思考，并力求构建一个较为合理的公益林市场化经营模式。     

Bright artificial light at night is associated with increased body mass,poor reproductive success and compromised disease tolerance in Australian budgerigars (Melopsittacus undulatus)

Artificial light at night (ALAN) can cause circadian disruption and result in adverse behavioral and ecological effects in free‐living birds, but studies on captive pet birds as companion animals have been infrequent. We studied the effects of exposure to bright ALAN on body mass, melatonin sulfate levels, reproduction and disease severity in Australian budgerigars (Melopsittacus undulatus) kept in captivity. During the experiment, birds were kept under outdoor temperature, humidity and natural photoperiod from September to December. A total of 48 birds were equally split into 4 groups (6 mating pairs each) and concurrently exposed to ALAN of 200 lux with different duration (0, 30, 60 and 90 min). Monthly observations were recorded for all dependent parameters. ALAN exposure increased mass gain and suppressed melatonin levels in a dose‐dependent manner, especially during December. In addition, ALAN exposure in all duration groups decreased egg production and reduced hatchability from 61% ± 14% in the ALAN‐unexposed control group to 0% in the ALAN‐exposed birds. Disease severity was also found to increase in line with the duration of ALAN exposure. In captive M. undulatus, ALAN exposure was demonstrated to affect photoperiodic regulation with subsequent excess mass gain and reproduction impairment, and increased susceptibility to infections plausibly through duration dose‐dependent suppression of melatonin. To the best of our knowledge, this is the first study to demonstrate a possible association between acute bright ALAN of increasing duration and both natural development of infections as well as reproductive cessation in captive birds. Our findings could be used to improve breeding conditions of captive birds.     

西北干旱灌区紫花苜蓿高产田施肥效应及推荐施肥量研究

为揭示紫花苜蓿氮、磷、钾肥效应,采用“3414”不完全正交回归设计,对紫花苜蓿氮、磷、钾肥合理配比施肥效应进行研究,同时对紫花苜蓿产量及蛋白总量进行肥效模型拟合。结果表明,氮、磷、钾对建植2年苜蓿产量的贡献为钾>磷>氮,对建植3年苜蓿产量的贡献为磷>钾>氮,建植2与3年苜蓿交互效应均表现为氮磷>氮钾>磷钾。氮、磷、钾对建植2年苜蓿蛋白总量的贡献为氮>钾>磷,对建植3年苜蓿蛋白总量的贡献为氮>磷>钾。建植2年苜蓿氮磷肥互作效应明显优于氮钾、磷钾互作;建植3年苜蓿氮磷、氮钾交互对苜蓿蛋白总量的增产效果明显大于磷钾交互。采用频度分析法,通过模拟寻优,得出建植2年紫花苜蓿目标产量大于平均产量17522kg·hm^-2时,优化施肥量为氮56.27~67.51kg·hm^-2、磷77.69~90.48kg·hm^-2、钾76.43~87.18kg·hm^-2;建植3年紫花苜蓿目标产量大于平均产量19234.1kg·hm^-2时,优化施肥量为氮46.75~57.66kg·hm^-2、磷80.15~92.28kg·hm^-2、钾57.79~69.74kg·hm^-2;建植2年紫花苜蓿目标蛋白总量大于平均2115kg·hm^-2时,优化施肥量为氮66.35~77.48kg·hm^-2、磷79.34~92.87kg·hm^-2、钾73.68~85.38kg·hm^-2;建植3年紫花苜蓿目标蛋白总量大于平均2656kg·hm^-2时,优化施肥量为氮68.44~79.50kg·hm^-2、磷72.74~85.96kg·hm^-2、钾50.68~61.61kg·hm^-2。     

双内源指示剂法测定兔饲粮消化能值及其预测模型的研究

本试验旨在研究利用双内源指示剂法测定兔饲粮养分消化率及消化能(DE)值,并建立兔饲粮DE值的预测模型。选用体重相近的4月龄獭兔30只,随机分为3组,每组10个重复,每个重复1只兔。每组饲喂1种饲粮,用全收粪法进行消化试验,用聚酯纤维筛网袋法测定了饲粮中的2种内源指示剂,即酸不溶木质素(ADL)和盐酸不溶灰分(AIA)+ADL的回收率。同时选取了山东省不同饲料公司生产的17种兔颗粒配合饲料,在各自兔养殖场进行饲养试验,利用双内源指示剂法测定兔饲粮DE值,建立兔饲粮DE值的预测模型。结果表明:1)全收粪法测得3种饲粮ADL的平均回收率为99.87%,ADL+AIA的平均回收率为96.81%,二者可作为理想的双内源指示剂。2)利用双内源指示剂法可以准确测定兔饲粮的各种养分消化率和DE值。3)兔饲粮DE值可以用饲粮中可消化有机物质(DOM)含量进行准确的预测:DE(M J/kg)=0.0204DOM(g/kg)或DE(M J/kg)=0.939 5+0.018 2DOM(g/kg)。4)利用兔饲粮中养分[粗蛋白质(CP)、粗脂肪(EE)、可溶性碳水化合物(NDSC)、半纤维素(HCEL)和纤维素(CEL)]含量建立兔饲粮DE值的预测模型为DE(MJ/kg)=0.016 6CP(g/kg)+0.0334EE(g/kg)+0.015 3NDSC(g/kg)+0.005 4HCEL(g/kg)+0.003 1CEL(g/kg)。由此可见,利用双内源指示剂法可以较好地预测兔饲粮的DE值。     

Mucopolysaccharidosis IIIA (Sanfilippo syndrome) in a New Zealand Huntaway dog with ataxia

Aim: To investigate the nature of a progressive ataxia in a New Zealand Huntaway dog.

Methods: The affected dog was examined clinically before being humanely killed and necropsied. Selected tissues were submitted to light and electron microscopy and to biochemical analyses.

Results: The histological lesions were interpreted as indicative of one of the forms of mucopolysaccharidosis type-III (dMPS-III), a lysosomal storage disease. Biochemically there was a deficiency of heparan sulphamidase. All the heparan sulphate chains had non-reducing-end glucosamine-N-sulphate residues.

Conclusion: The disease is dMPS-IIIA (Sanfilippo syndrome). An autosomal recessive mode of inheritance can be provisionally assumed from the nature of this disease in other species.     

生长猪大米蛋白消化能、代谢能的评定及预测模型研究

本试验通过采集我国多个地区大米蛋白样品,分析大米蛋白常规成分,测定生长猪消化能(DE)、代谢能(ME),建立大米蛋白常规成分与生长猪DE、ME之间的关系。试验选用体重(33.0±1.3)kg的"杜×长×大"三元杂交健康去势公猪12头,采用2个6×6拉丁方试验设计,包括1种基础饲粮和11种大米蛋白替代15%基础饲粮的试验饲粮。采用全收粪法和套算法结合测定大米蛋白猪DE、ME,并将大米蛋白的常规成分与猪DE、ME进行相关和回归分析,建立大米蛋白猪DE、ME预测模型。结果表明,11种大米蛋白风干基础下猪DE为(18.13±1.12)M J/kg,M E为(16.44±1.59)M J/kg。由此得出,大米蛋白猪DE最佳预测模型(绝干基础)为DE=22.17-0.51NDF(R2=0.50,RSD=0.93),DE=18.58-0.49 CF+0.31 EE(R2=0.70,RSD=0.77);M E最佳预测模型(绝干基础)为ME=21.42-0.74 NDF(R2=0.52,RSD=1.30)。NDF为大米蛋白猪DE、M E最佳预测因子。     

Usefulness of the murine model to study the immune response against Histoplasma capsulatum infection

The present paper is an overview of the primary events that are associated with the histoplasmosis immune response in the murine model. Valuable data that have been recorded in the scientific literature have contributed to an improved understanding of the clinical course of this systemic mycosis, which is caused by the dimorphic fungus Histoplasma capsulatum. Data must be analyzed carefully, given that misinterpretation could be generated because most of the available information is based on experimental host–parasite interactions that used inappropriate proceedings, i.e., the non-natural route of infection with the parasitic and virulent fungal yeast-phase, which is not the usual infective phase of the etiological agent of this mycosis.     

生物地球化学模型DNDC的研究进展与碳动态模拟应用

脱氮脱碳模型(denitrification-decomposition,DNDC)是通过计算反硝化和有机质分解来模拟氮和碳从土壤丢失而转移入大气时的主要生物地球化学过程模型。作为目前国际上最成功的模拟陆地生物地球化学循环的模型之一,本文主要阐述了DNDC模型的发展过程及其结构,整理了DNDC模型在碳动态模拟过程中的主要研究进展,总结了当前DNDC模型在碳动态模拟领域的应用热点和优势。     

Pigs as an experimental model for systemic Mycobacterium avium infectious disease

Mycobacterium avium complex (MAC) is an opportunistic pathogen in AIDS patients and pigs, and causes dissemination through primary intestinal lesions. However, its pathogenesis is not well understood. In this article, we hypothesize that pigs can provide a suitable experimental model of disseminated MAC disease. We compared the initial route of infection, the characteristics of the pathogenic strains, the immunological status of the hosts, and the histological characteristics. The route of infection and infective strains are similar in AIDS patients and pigs. Pigs can respond to infection by the formation of systemic epithelioid granuloma with sufficient cell-mediated immunity. However, there are differences in immunological status and histological features between AIDS patients and pigs. Therefore, pigs might be used as an appropriate animal model because of their good cell mediated immunity triggered by systemic mycobacterial infection. In conclusion, MAC infections in AIDS patients and pigs show similarities in terms of the initial route of infection and the genetic characteristics of the pathogenic strains.