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1.
Roy Fuller 《Biologia》2006,61(6):751-754
The results obtained by probiotic supplementation are a function of the action of live microorganisms on the very complex population of microorganisms in the gut. The outcome of this extremely complicated interaction is bound to be subject to variation and can be influenced by several factors relating to the product, the administrator and the consumer. If we can define the reasons for these inconsistencies we will be better able to develop improved preparations which when given at the right time and in the right way will give the expected response. Presented at the Second Probiotic Conference, Košice, 15–19 September 2004, Slovakia  相似文献   
2.
Most cats surrendered to nonhuman animal shelters are identified as unowned, and the surrender reason for these cats is usually simply recorded as “stray.” A cross-sectional study was conducted with people surrendering cats to 4 Australian animal shelters. Surrenderers of unowned cats commonly gave surrender reasons relating to concern for the cat and his/her welfare. Seventeen percent of noncaregivers had considered adopting the cat. Barriers to assuming ownership most commonly related to responsible ownership concerns. Unwanted kittens commonly contributed to the decision to surrender for both caregivers and noncaregivers. Nonowners gave more surrender reasons than owners, although many owners also gave multiple surrender reasons. These findings highlight the multifactorial nature of the decision-making process leading to surrender and demonstrate that recording only one reason for surrender does not capture the complexity of the surrender decision. Collecting information about multiple reasons for surrender, particularly reasons for surrender of unowned cats and barriers to assuming ownership, could help to develop strategies to reduce the number of cats surrendered.  相似文献   
3.
中国特有植物台湾杉的生物学特性及其保护   总被引:5,自引:0,他引:5  
本文全面地综述了我国一级国家重点保护植物台湾杉的生物学特性,其中有外部形态特征,内部结构包括苗端、叶片、树皮及木材结构,雌雄配子体与胚胎发育,花粉和染色体。此外还有台湾杉的组织培养、地理分布,生态学与群落学特性等。最后,本文作者还初步分析了台湾杉的濒危原因,并提出了具体保护措施。  相似文献   
4.
中国鹅掌揪自然种群动态及其致危生境的研究   总被引:1,自引:1,他引:0       下载免费PDF全文
  相似文献   
5.
安徽短萼黄连种群特性及其濒危机制探讨   总被引:4,自引:1,他引:3  
张莉  张小平 《应用生态学报》2005,16(8):1394-1398
对安徽省境内短萼黄连的地理分布、分布地自然概况及种群大小、分布格局、年龄结构等种群特性进行研究.结果表明,短萼黄连在安徽省主要分布于九华山、黄山、清凉峰和牯牛降等山区.其生境涉及林冠下和水沟边两种类型,均表现为阴湿、土壤疏松、呈酸性而富含有机质,要求光照荫蔽度平均达到70%以上,空气相对湿度70%~90%,土壤含水量在30%以上.现有短萼黄连种群均为高群集分布,年龄结构不合理,且多为小种群,表明种群已处于相对不稳定阶段.自然生境的严重破坏、成年植株的过度采挖对短萼黄连种群的生存构成严重威胁,是造成部分野生种群个体数量急剧减少的主要原因.  相似文献   
6.
Summary From a behavioural perspective on adaptive female choice, I developed a by-product runaway model of adaptive mate choice. The model illustrates the evolution of the tail size of peacocks. I consider the causal mechanisms of adaptive female choice: (1) why (ultimate reasons); (2) how (proximate mechanisms). Assumptions are developed based on these behavioural aspects. For (1) ultimate reasons, I assume that many male losers (low-fitness males) always occur due to genetic and environmental uncertainty (A-1). For (2) proximate mechanisms, I assume that losers tend to differ in the expression of a fitness-sensitive trait (an ultimate target, e.g. body size; A-2), that the fitness-sensitive trait correlates with a secondary sexual trait (a proximate cue, e.g. allometry in body size and tail size; (A-3), and that the cue trait has a genetic basis that is independent of the target trait (e.g. a genetic basis in tail ratio to body size; A-4). The model's results are: persistent female choice by means of a proximate cue (R-1); by-product selection on the independent genetic basis of the cue (R-2); and the non-adaptive or maladaptive runaway evolution of the male proximate cue (R-3). In this model, female mate preferences are non-arbitrary and adaptive, whereas the resulting evolution of male secondary sexual traits is non-adaptive in the sense of survival selection.  相似文献   
7.
神农架国家级自然保护区连香树资源现状及其保护   总被引:11,自引:0,他引:11  
于1986~1989、1992、1997~1998年期间,对神农架自然保护区连香树资源进行了调查,发现连香树主要分布在海拔1400~1600m的山谷,以零星分布为主。在分析连香树分布现状的基础上,探讨连香树濒危的原因,提出了相应的保护措施。  相似文献   
8.
Objectives : This study examined reasons for seeking treatment reported by obese patients diagnosed with binge eating disorder (BED). Research Methods and Procedures : Participants were 248 adults (58 men and 190 women) who met DSM criteria for BED. Participants were recruited through advertisements for treatment studies looking for persons who wanted to “stop binge eating and lose weight.” Patients’ reasons for seeking treatment were examined with respect to demography (gender and age), obesity (BMI and age of onset), features of eating disorders, and associated psychological functioning (depression and self‐esteem). Results : Of the 248 participants, 64% reported health concerns and 36% reported appearance concerns as their primary reason for seeking treatment. Reasons for seeking treatment did not differ significantly by gender. Patients seeking treatment because of appearance‐related reasons had lower BMIs than those reporting health‐related reasons (34.8 vs. 38.5, respectively), but they reported greater body dissatisfaction, more features of eating disorders, and lower self‐esteem. Discussion : Reasons that prompt treatment seeking among obese individuals with BED reflect meaningful patient characteristics and, therefore, warrant assessment and consideration during treatment planning. Further research is needed to determine whether reasons for treatment seeking among different obese patient groups affect treatment outcomes.  相似文献   
9.
鹅掌楸种群间光生态适应性的分化   总被引:12,自引:0,他引:12       下载免费PDF全文
通过对鹅掌楸7个不同种群幼苗的光合生长年进程、光合速率、光饱和点和光补偿点,以及不同光生境条件下的叶绿素含量和叶绿素a/b比值的实验测定和生长量的统计,结果表明,种群间存在明显的光生态适应性分化。该物种地理分布上的西部亚区种群的光合适应能力和生长势总体上强于东部亚区的种群。而在西部亚区中又以金平、盐津种群的适应力和生存力更强。本研究支持该物种种群的生存能力由西向东逐渐下降,居于东部亚区中的种群其濒危程度更为严重的观点。这种濒危过程中的生态适应性的分化,说明该物种的濒危,在很大程度上是“致危生境”造成的。  相似文献   
10.
中国鹅掌楸自然种群动态及其致危生境的研究   总被引:22,自引:0,他引:22       下载免费PDF全文
本文对天然鹅掌楸的地理分布、种群特征及其环境因子影响等方面进行了分析讨论,试图揭示其致危机理。鹅掌楸星散间断分布型式、种群规模较小、种群结构的衰退趋势和对生境的特定要求,反映出该物种正处在濒危状态。并提出自然种群的消亡是由于处于“致危生境”的缘故。应借助于人为帮助,改善生境条件,将不同种群的鹅掌楸引种到合适的生境中,扩大其种群规模,促进不同种群之间的基因交流,以利保护。  相似文献   
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