Evaluation of infertility in the bitch

The majority of bitches that are brought to a veterinarian for reproductive evaluation are actually healthy. Infertility in the bitch is most commonly due to inappropriate breeding management rather than an inability to conceive. Before embarking on an exhaustive medical evaluation, it is important to obtain a thorough history and physical examination to identify any problems. Completion of a routine database assists in detecting significant systemic illness that may impact infertility. After consideration of history, physical examination, and minimum database, fertility problems are most commonly considered in one of four categories: abnormal estrous cycles, normal estrous cycles, failure to breed, or failure to carry a litter to term. This classification system aids in construction of a differential list and systematic evaluation of all differentials. The majority of diagnostic tests required are available to the general practitioner. Before any treatment for infertility, adequate health management must be ensured. Specific treatment for the most common causes of infertility is centered on appropriate breeding management.     

干旱胁迫对苗木蒸腾耗水日变化的影响

采用BP340 0精密电子天平 ,于 2 0 0 2年夏季研究了在不同水分胁迫条件下 ,4种北方主要造林树种苗木的日蒸腾耗水速率及实际耗水量变化规律 .结果表明 ,在正常水分条件下 ,各苗木的日最大耗水速率出现在 10 :0 0— 14 :0 0之间 ,阔叶树种的蒸腾耗水速率远远大于针叶树种 ,是针叶树种的 5～ 7倍 ,苗木的耗水速率排序为 :黄栌 >火炬树 >侧柏 >油松 ;1年生的黄栌和火炬树与 5年生侧柏的日耗水量相差不大 ,是油松的 1倍 .当苗木受到干旱胁迫后 ,苗木的日最大耗水速率会提前 ,蒸腾速率迅速下降 ,但下降幅度不同 ,耗水速率排序为 :火炬树 >黄栌 >油松 >侧柏 .在中等干旱胁迫下 ,油松、火炬树、侧柏、黄栌的日平均耗水速率分别下降了 5 4 0 %、6 8 6 %、87 2 %和 90 2 % ;侧柏和黄栌之间 ,油松和火炬树之间的日耗水量基本相同 ,但侧柏和黄栌只有油松和火炬树的一半 ;干旱胁迫继续加重后 ,油松、火炬树、侧柏、黄栌的日平均耗水速率只有水分正常条件下的 15 7%、12 1%、4 3%和 9 2 % ,日耗水总量下降到 5 %～10 % ,4个树种间相差不大 .     

Ecoviability for ecosystem‐based fisheries management

Reconciling food security, economic development and biodiversity conservation is a key challenge, especially in the face of the demographic transition characterizing many countries in the world. Fisheries and marine ecosystems constitute a difficult application of this bio‐economic challenge. Many experts and scientists advocate an ecosystem approach to manage marine socio‐ecosystems for their sustainability and resilience. However, the ways by which to operationalize ecosystem‐based fisheries management (EBFM) remain poorly specified. We propose a specific methodological framework—viability modelling—to do so. We show how viability modelling can be applied using four contrasted case‐studies: two small‐scale fisheries in South America and Pacific and two larger‐scale fisheries in Europe and Australia. The four fisheries are analysed using the same modelling framework, structured around a set of common methods, indicators and scenarios. The calibrated models are dynamic, multispecies and multifleet and account for various sources of uncertainty. A multicriteria evaluation is used to assess the scenarios’ outcomes over a long time horizon with different constraints based on ecological, social and economic reference points. Results show to what extent the bio‐economic and ecosystem risks associated with the adoption of status quo strategies are relatively high and challenge the implementation of EBFM. In contrast, strategies called ecoviability or co‐viability strategies, that aim at satisfying the viability constraints, reduce significantly these ecological and economic risks and promote EBFM. The gains associated with those ecoviability strategies, however, decrease with the intensity of regulations imposed on these fisheries.     

Active habitat selection by pre-settlement reef fishes

Our understanding of habitat selection by reef fish larvae has changed dramatically in the last 10 years. Fish larvae have long been considered passive particles at the mercy of ocean currents, tides and weather events. For reef fishes, ecological evidence has shown that passive dispersal alone often cannot explain larval distributions, suggesting active behaviour by reef fish larvae. While behaviourally modified passive transport may be important, recent work demonstrates that some reef fish larvae have the capability to actively swim to settlement habitat. They can orientate to reefs from distances of at least 1 km and can swim at speeds of 13.5 cm s^?1 for several days. The question then becomes, what are the cues that fish larvae use to orientate to reefs? Ambient reef sound has been shown to be attractive to reef fish larvae, and current research aims to understand better the nature and use of these acoustic cues. Other potential cues include chemoreception/olfaction, wave cues and visual location of reefs. A better understanding of active habitat selection and the underlying sensory and behavioural mechanisms will improve our knowledge of recruitment processes in reef fish ecology, and may have implications for active management of reef fish populations.     

Evaluating the use of garlic (Allium sativum) for the remedy of Cryptocaryon irritans in guppies (Poecilia reticulata)

Garlic (Allium sativum) has been shown to possess antimicrobial properties against a range of disease‐causing agents, including fish parasites. Our study aimed to investigate the potential use of garlic as a treatment against Cryptocaryon irritans infection, using guppies (Poecilia reticulata) as the fish model. Garlic was freeze‐dried, powdered, and used as it is or as an aqueous extract. The content of allicin, its main active ingredient, was 1.25 mg/g in garlic powder and 0.82 mg/ml in the aqueous extract, as determined by HPLC analysis. Aqueous garlic extract fully immobilized C. irritans theronts and protomonts within 20 and 40 min, respectively, following exposure to 5 µl/ml. Treatment trials were performed, in which infected fish were fed with garlic powder‐supplemented feeds (5%, 10%, or 20% supplementation), bathed in garlic aqueous extract (250 or 500 µl/L) and subjected to a combined treatment which included both feeding and bathing. Results revealed that the tested treatments failed to cure the infection, though reduction in infection intensity on the caudal fin, but not on the gills, was evident following dietary supplementation with 20% of powdered garlic in one of the trials.     

Use of state‐space modelling to identify ecological covariates associated with trends in pinniped demography

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