小肽营养素对奶牛泌乳性能的影响

试验选择泌乳期中国荷斯坦奶牛32头,随机分为4组,A组(对照组)为基础精料日粮组;B、C、D组分别为基础精料日粮 0.1%、0.3%、0.5%小肽营养素。正试期28d。结果表明,添加0.1%、0.3%、0.5%小肽营养素后,奶牛头日平均产奶量分别提高1.67kg(6.38%)(P<0.05)、1.75kg(6.69%)(P<0.05)和1.64kg(6.27%)(P<0.05)。添加小肽营养素后,乳蛋白和乳脂率均有所提高,其趋势随小肽营养素添加量的增加而提高。添加0.1%、0.3%、0.5%小肽营养素后,奶牛头日净增效益3.52元、3.40元、2.86元。综合生产性能和经济效益,以添加0.1%-0.3%小肽营养素为适宜。     

Effects of subsurface aeration and trinexapac-ethyl application on soil microbial communities in a creeping bentgrass putting green

The sensitivity of creeping bentgrass (Agrostis palustris Huds.) to the extreme heat found in the southeastern United States has led to the development of new greens-management methods. The purpose of this study was to examine the effects of subsurface aeration and growth regulator applications on soil microbial communities and mycorrhizal colonization rates in a creeping bentgrass putting green. Two cultivars (Crenshaw and Penncross), a growth regulator (trinexapac-ethyl), and subsurface aeration were evaluated in cool and warm seasons. Total bacterial counts were higher in whole (unsieved) soils than in sieved soils, indicating a richer rhizosphere soil environment. Mycorrhizal infection rates were higher in trinexapac-ethyl (TE) treated plants. High levels of hyphal colonization and relatively low arbuscule and vesicle occurrence were observed. Principal components analysis of whole-soil fatty acid methyl ester (FAME) profiles indicated that warm-season microbial populations in whole and sieved soils had similar constituents, but the populations differed in the cool season. FAME profiles did not indicate that subsurface aeration and TE application affected soil microbial community structure. This is the first reported study investigating the influences of subsurface aeration and TE application on soil microorganisms in a turfgrass putting green soil.     

Investigating translated data of the German soil‐quality assessment using pinpoint field validation

In contrast to modern soil‐profile characterization, alternative soil classifications, such as the German soil‐quality assessment (Bodenschätzung), bear a lower degree of scientific quality. However, despite originally created to determine the tax value of arable land and grassland, its high spatial resolution and complete areal coverage makes soil‐quality assessment a valuable tool. To assess its performance in a mountainous setting soil‐layer data of 60 soil pits, recorded in Bavaria (SE Germany) in the course of the soil‐quality assessment, were translated into German soil‐science terminology using the translation program NIBIS®. With regard to soil type and texture the translation was checked using pinpoint field validation based on soil‐science terminology. 57% of soil types and 61% of texture were correctly translated by NIBIS®. To obtain information about probable parameters that can explain the different results readily available parameters such as elapsed time between soil‐quality assessment and validation, altitude, slope, aspect, horizon thickness, lower edge of horizon, as well as weathering surface and silicate‐weathering rate derived from geological maps were used. Differences in topsoil texture were somewhat related to petrographic parameters, those of the lower subsoil showed a weak dependence to topographic parameters. The NIBIS® translation overrated the silt content to the expense of sand. Clay was the best‐matched texture class. The shift towards silty texture classes was the dominant factor for the differences of texture‐related values of the available water capacity and hydraulic conductivity. Both parameters as derived from the NIBIS® translation on the one and from field validation on the other hand were used to evaluate the water‐retention capacity of individual soil profiles. Despite differing input data the soils' water‐retention capacity was rated identical. Thus, a certain degree of disagreement between the texture data obtained from NIBIS® translation and from field validation is tolerable, if the eventual soil‐function evaluation is based on wide classes of texture or of secondary parameters derived from texture.     

Linux操作系统实验教学研究

Linux操作系统具有很强的理论性和实践性,针对Linux操作系统实验教学,提出了利用VMware虚拟机搭建Linux平台的过程,并按照操作系统的功能模块循序渐进地设计了七个实验项目,通过实验使学生深入理解Linux操作系统,提高学生的学习兴趣、自主性及操作能力、编程能力。     

Perfluorooctanoate (PFO) in Forest Soils near a Fluoropolymer Manufacturing Facility

After elevated concentrations of perfluorooctanoate (PFO) were found in river and groundwater in the vicinity of a fluoropolymer manufacturing facility, numerous soils at adjacent sites were sampled in 2007. Within a 5-km northeast-oriented sector around a probable point source, 20 forest sites were investigated and compared to deposition and groundwater data. PFO concentrations up to 600 µg/kg were detected in the soils, and PFO concentrations typically decreased toward deeper soil depths. In mixed or deciduous forests, maximum concentrations of PFO occurred in the topsoil, pointing to the favorable decomposition and incorporation of deciduous litter. PFO concentrations of the organic layer over the 20 sampling sites were interpolated using ordinary kriging. Highest PFO content in the organic layer was located about 500 m away from the point source in the regional wind direction, decreasing asymptotically outwards. Long-term monitoring data pointed to an accumulation of PFO over time in the organic layer. The data suggest that PFO might be released in the course of litter decomposition and transported toward deeper soil regions only gradually. The soils’ PFO concentrations reflect the deposition data. The transport link toward groundwater is currently established in lysimeter studies.     

Chlorophyll meter predicts nitrogen status of tall fescue

The nitrogen (N) status of a crop can be used to predict yield and supplemental N fertilizer requirements, and rapid techniques for evaluating the N status of crops are needed. A study was conducted to determine the feasibility of using a hand held chlorophyll meter (SPAD 502, Minolta Co. Ltd., Japan) to monitor N status of tall fescue (Festuca arundinacea Schreb.). Four diverse tall fescue genotypes were grown at three locations in Alabama and fertilized at four N‐rates from 0 to 336 kg ha^‐1. A similar experiment was conducted in the greenhouse using soil from the same field sites. Chlorophyll meter readings (SPAD) were taken, and extractable chlorophyll content, tissue N concentration and dry matter yield were determined at harvest. SPAD, extractable chlorophyll content, tissue N concentration, and dry matter yield increased quadratically (0.67 < R² < 0.99) with increasing N fertilization in both experiments. All genotypes responded similarly to applied N, with some differences in magnitude. Relationships between SPAD meter readings and extractable chlorophyll and tissue N concentrations were linear with r² > 0.95. An additional independent variable, the square root of the inverse of SPAD, lowered the residual mean square by 11 and 16%, respectively, for tissue‐N and chlorophyll concentrations, but did not increase the R². This would be preferred for predictive purposes. Tissue N concentrations at higher N‐rates were sufficient for maximum yield which occurred at 290 and 248 kg N ha^‐1 for greenhouse and field, respectively, but were lower than previously reported sufficiency values. The chlorophyll meter is an easy and efficient method of detecting tall fescue N status.     

基于JPEG2000的Kakadu结构分析与应用

Kakadu2.2是目前JPEG 2000算法实现效率较高的开源系统。Kakadu采用三层体系结构很大程度上简化了系统复杂性,并以数据处理子系统为引擎高效实现JPEG2000编解码器,采用面向接口方式使其成为一个具有良好的可复用性系统。对系统体系结构、核心系统库及应用程序使用方法进行深入地分析和研究,为以Kakadu为基础的图像/视频处理软件开发者提供有益的帮助。     

Effectiveness of acupuncture in veterinary medicine: systematic review

Acupuncture is a popular complementary treatment option in human medicine. Increasingly, owners also seek acupuncture for their animals. The aim of the systematic review reported here was to summarize and assess the clinical evidence for or against the effectiveness of acupuncture in veterinary medicine. Systematic searches were conducted on Medline, Embase, Amed, Cinahl, Japana Centra Revuo Medicina and Chikusan Bunken Kensaku. Hand-searches included conference proceedings, bibliographies, and contact with experts and veterinary acupuncture associations. There were no restrictions regarding the language of publication. All controlled clinical trials testing acupuncture in any condition of domestic animals were included. Studies using laboratory animals were excluded. Titles and abstracts of identified articles were read, and hard copies were obtained. Inclusion and exclusion of studies, data extraction, and validation were performed independently by two reviewers. Methodologic quality was evaluated by means of the Jadad score. Fourteen randomized controlled trials and 17 nonrandomized controlled trials met our criteria and were, therefore, included. The methodologic quality of these trials was variable but, on average, was low. For cutaneous pain and diarrhea, encouraging evidence exists that warrants further investigation in rigorous trials. Single studies reported some positive intergroup differences for spinal cord injury, Cushing's syndrome, lung function, hepatitis, and rumen acidosis. These trials require independent replication. On the basis of the findings of this systematic review, there is no compelling evidence to recommend or reject acupuncture for any condition in domestic animals. Some encouraging data do exist that warrant further investigation in independent rigorous trials.     

Serum concentrations of adiponectin and characterization of adiponectin protein complexes in dogs

OBJECTIVE: To assess serum concentrations of adiponectin and characterize adiponectin protein complexes in healthy dogs. ANIMALS: 11 healthy dogs. PROCEDURES: Sera collected from 10 dogs were evaluated via velocity sedimentation and ultracentrifugation, SDS-PAGE, western immunoblotting, and radioimmunoassay. Visceral adipose tissue (approx 90 g) was collected from the falciform ligament of a healthy dog undergoing elective ovariohysterectomy, and adiponectin gene expression was assessed via a real-time PCR procedure. RESULTS: Adiponectin gene expression was detected in visceral adipose tissue. Serum adiponectin concentrations ranged from 0.85 to 1.5 microg/mL (mean concentration, 1.22 microg/mL). In canine serum, adiponectin was present as a multimer, consisting of a low-molecular-weight complex (180 kd); as 3 (180-, 90-, and 60-kd) complexes under denaturing conditions; as 2 (90- and 60-kd) complexes under reducing conditions; and as a dimer, a monomer, and globular head region (60, 30, and 28 kd, respectively) under reducing-denaturing conditions. It is likely that adiponectin also circulates as a high-molecular-weight (360- to 540-kd) complex in canine serum, but resolution of this complex was not possible via SDS-PAGE. CONCLUSIONS AND CLINICAL RELEVANCE: After exposure to identical experimental conditions, adiponectin protein complexes in canine serum were similar to those detected in human and rodent sera. Circulating adiponectin concentrations in canine serum were slightly lower than concentrations in human serum. Adiponectin gene expression was identified in canine visceral adipose tissue. Results suggest that adiponectin could be used as an early clinical marker for metabolic derangements, including obesity, insulin resistance, and diabetes mellitus in dogs.     

Avian influenza in ovo vaccination with replication defective recombinant adenovirus in chickens: vaccine potency, antibody persistence, and maternal antibody transfer

Protective immunity against avian influenza (AI) can be elicited in chickens in a single-dose regimen by in ovo vaccination with a replication-competent adenovirus (RCA)-free human adenovirus serotype 5 (Ad)-vector encoding the AI virus (AIV) hemagglutinin (HA). We evaluated vaccine potency, antibody persistence, transfer of maternal antibodies (MtAb), and interference between MtAb and active in ovo or mucosal immunization with RCA-free recombinant Ad expressing a codon-optimized AIV H5 HA gene from A/turkey/WI/68 (AdTW68.H5(ck)). Vaccine coverage and intrapotency test repeatability were based on anti-H5 hemagglutination inhibition (HI) antibody levels detected in in ovo vaccinated chickens. Even though egg inoculation of each replicate was performed by individuals with varying expertise and with different vaccine batches, the average vaccine coverage of three replicates was 85%. The intrapotency test repeatability, which considers both positive as well as negative values, varied between 0.69 and 0.71, indicating effective vaccination. Highly pathogenic (HP) AIV challenge of chicken groups vaccinated with increasing vaccine doses showed 90% protection in chickens receiving > or = 10(8) ifu (infectious units)/bird. The protective dose 50% (PD50) was determined to be 10(6.5) ifu. Even vaccinated chickens that did not develop detectable antibody levels were effectively protected against HP AIV challenge. This result is consistent with previous findings ofAd-vector eliciting T lymphocyte responses. Higher vaccine doses significantly reduced viral shedding as determined by AIV RNA concentration in oropharyngeal swabs. Assessment of antibody persistence showed that antibody levels of in ovo immunized chickens continued to increase until 12 wk and started to decline after 18 wk of age. Intramuscular (IM) booster vaccination with the same vaccine at 16 wk of age significantly increased the antibody responses in breeder hens, and these responses were maintained at high levels throughout the experimental period (34 wk of age). AdTW68.H5(ch)-immunized breeder hens effectively transferred MtAb to progeny chickens. The level of MtAb in the progenies was consistent with the levels detected in the breeders, i.e., intramuscularly boosted breeders transferred higher concentrations of antibodies to the offspring. Maternal antibodies declined with time in the progenies and achieved marginal levels by 34 days of age. Chickens with high maternal antibody levels that were vaccinated either in ovo or via mucosal routes (ocular or spray) did not seroconvert. In contrast, chickens without MtAb successfully developed specific antibody levels after either in ovo or mucosal vaccination. These results indicate that high levels of MtAb interfered with active Ad-vectored vaccination.