一类与贝努利双纽线和共轭点有关的广义解析函数的三阶Hankel行列式

设A表示在单位圆盘D={z:|z|1}内解析且满足f(0)=f′(0)-1=0的函数类.首先,引入了与贝努利双纽线有关且具有共轭点的广义解析函数类SL~*_c(α,μ):■然后,讨论了此类函数的三阶Hankel行列式H_3(1),得到其上界估计.     

水生态区划理论方法及全国水生态区划方案

针对我国复杂的水生态状况,建立了一套水生态区划理论方法,并提出全国水生态区划方案。遵照区域相关性原则、协调原则、主导功能原则和分级区划原则,采用三级分区的思路,综合气候、地理、水资源条件、人类活动影响及生态功能类型等诸多因素,详细阐述各级分区的划分依据、命名与编码原则。基于对全国范围内主要水生态系统特征、人类活动影响及水生态类型的认识,将全国划分为6个一级区、34个二级区和130个三级区。     

Computed tomography as a method of estimating bone mineral content in horses

With the advancement of technology, more tools and methods are being made available for the assessment of bone density in the live animal. Computed tomography (CT) is one such tool. In a CT scan, x-rays are passed through a subject and detectors record transmitted energy. The CT computer then constructs cross-sectional images from this data to represent the internal anatomy.The first objective of this study was to investigate CT as a means of estimating bone mineral content of the equine third metacarpal bone. Our hypothesis was that the cross-sectional area of the third metacarpal bone, as measured on CT images, would correlate significantly with ash weight of that section. Our second objective was to use CT to measure and compare bone density in the dorsal, palmar, lateral and medial cortices of the equine third metacarpus. We hypothesized that CT would detect differences in density by cortex.Twelve cadaver thoracic limb specimens, from horses of varying age, breed and prior use, were scanned on a CT 9800 (GE Medical Systems). Scanned sections of the limb were then skinned, dried, ether-extracted and ashed in a muffle furnace. Bone mineral content was expressed as grams of ash/cm section of bone. The image recorded by the CT was developed and assessed using an imaging photodensitometer and a corresponding software package to estimate the area of each bone section. Correlation was determined using SAS (6.12). Differences in bone density by cortex were calculated using a simple t-test. The maximum, minimum and mean estimates of third metacarpal bone cross-sectional area as determined by CT were 519, 351 and 423 mm², respectively, while the maximum, minimum and mean ash weights were 8.9, 4.8 and 6.4 g/cm, respectively. Estimates of bone mineral content by ash and cross-sectional area as determined by CT were significantly correlated (r=.91, P=.0001). There was no difference in CT density numbers between lateral and medial cortices, however the dorsal cortex was lower in density than the lateral (P<.05) and the palmar cortex was lower in density than all other cortices (P<.05). This data suggests that in a research setting, CT is an effective method by which to calculate cross-sectional area and, hence, estimate bone mineral content. Computed tomography was also able to detect differences in bone density by cortex.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 6. Bone parameters in the third metacarpal and third metatarsal bones

AIM: To determine the effect of a known training regimen on the size and mineral content of the third metacarpal (Mc3) and third metatarsal (Mt3) bones of 2-year-old Thoroughbred horses trained on racetracks.

METHODS: Mc3 and Mt3 of seven horses trained on grass and sand tracks were scanned at several sites using conventional quantitative and peripheral computed tomography (CT). Bone dimensions and density in the diaphysis and epiphysis were compared with those from seven untrained horses. Calcein label was injected in two clusters, during Weeks 9 and 12. The extent and rate of diaphyseal modelling was determined by confocal fl uorescent microscopic examination of thin plane parallel sections of the mid-metacarpal region.

RESULTS: Volumetric bone mineral density (BMDv) of the epiphysis was markedly higher and of the diaphysis was slightly higher in trained compared with untrained horses, but greater bone size in the trained horses had the greatest effect on an index of bone strength. Active osteons, defined as Haversian systems containing calcein label, were fewer, of smaller diameter at the time of calcein injection, and had a greater bone apposition rate in trained than in untrained horses.

CONCLUSIONS: Conventional training of 2-year-old Thoroughbred racehorses over a 13-week period had a significant effect on bone size, density and strength index when compared to untrained horses.

CLINICAL RELEVANCE: Bone responded rapidly to early training. The data provide reference values and sites for use in longitudinal studies of commercial training regimens.     

Combined excision and intralesional bevacizumab for sebaceous carcinoma of the eyelid in an Amur tiger (Panthera tigris altaica)

An 18‐year‐old zoo‐kept female Amur tiger presented with an approximately 5 mm diameter lateral canthal eyelid mass in the left eye which grossly appeared red and irregular. The mass was completely excised via lateral canthoplasty. Histopathologic evaluation was consistent with a diagnosis of sebaceous cell carcinoma, which is a potentially aggressive cutaneous neoplasm. The sebaceous carcinoma recurred within 3 months and slowly increased in size until a second surgical excision was performed 9 months following the first surgery. The second surgical excision was combined with intralesional injection of 10 mg of the antiangiogenic drug bevacizumab. Histology confirmed the diagnosis. The tiger was euthanized 16 months postoperatively for reasons unrelated to, and without recurrence of, the eyelid neoplasm. At postmortem, no gross periocular or metastatic lesions were noted, and histopathology of the lateral canthus provided no evidence of recurrence. Surgical excision combined with intralesional bevacizumab treatment induced life‐long resolution of the sebaceous carcinoma. Bevacizumab treatment may be associated with the regression of periocular angiogenic proliferative conditions, including neoplasia, by inhibiting angiogenesis.     

《水土保持学》(第3版)修编思路及内容变化分析

《水土保持学》与《水土保持学》(第2版)分别于1995年和2005年出版,累计印数超过2万册,得到了广大使用单位及读者的大力支持与肯定,已成为全国高等院校水土保持及相关课程的教科书、重要参考书,水土保持与荒漠化防治专业的工具书及考研必备教材。《水土保持学》(第3版)是根据"十二五"全国重点教材编写计划以及水土保持工作范畴的不断扩大和新需求的不断出现,在第2版的基础上修编的新教材。以第2版为基础,通过分析第3版的编写思路、内容变化及其特点,使读者能够快速了解第3版的新内容和编排思路。     

我国生物技术育种现状与发展趋势

生物育种是现代农业史上应用推广最迅速的技术,并已在全球范围内产生了巨大的社会、经济和生态效益。然而目前我国主要农作物的品种选育仍停留在以表型选择为主的传统育种模式。这种经验育种不仅周期长而且品种改良进度缓慢,难以满足我国强劲的经济发展需求。而生物育种技术突破了传统育种技术的种种局限,使农作物育种变得更精确、更高效、更可控且可预见,可促进实现中国主要作物由“经验育种”向“精确育种”的战略性转变,有利于加速培育高产、优质、抗逆、广适的作物新品种。着重介绍了转基因、分子标记辅助选择、分子设计和智能不育这四种生物技术在水稻和玉米两大作物育种中的应用现状与发展趋势,可为我国农业和科技管理部门、生物技术工作者、育种家和种业企业提供参考。     

The switching median filter denoising algorithm for encrypted images

Sometimes it is necessary to send the image data to the third party device to process. To ensure the image safety, it is necessary to encrypt the image before processing. A new algorithm for encrypted image processing is proposed. The image owner encrypts