Temperature,density and ammonia effects on growth and fecundity of the ramshorn snail (Helisoma anceps)

Ramshorn snail (Helisoma anceps) is a freshwater gastropod found all over North America and is also an essential component to the larval and juvenile culture of endangered Delta Smelt (Hypomesus transpacificus) at the UC Davis Fish Conservation and Culture Lab (FCCL). H. anceps has been proven effective in cleaning the excess algae while not harming the larvae. A challenge at the FCCL has been having a reliable source of these snails, since previously it has been dependent upon nature and never guaranteed there would be enough to meet the needs of the FCCL. Experiments were conducted to assess the effects of temperature, food types, rearing density and total ammonia nitrogen (TAN) concentrations. Procedures recommended to increase snail fecundity for the FCCL are to rear spawning parent snails and the resultant eggs at a high temperature (16–20°C) and with a low TAN concentration (0–5 mg/L). Newly hatched snails need to be cultured at a low density (about one snail/20 cm²). After the snails grow to an acceptable size (1.3 cm diameter), they could be set aside and cultured in an environment with less optimal water quality parameters such as a high TAN level (as high as 20 mg/L) and low temperature (12°C) for quantity control prior to use.     

Chainlike formation of particle deposits in fluid-particle separation

A theory is proposed for the formation and growth of particle dendrites on a collector placed in an aerosol or hydrosol stream. It is based on the interplay of two intrinsic properties of suspended particles: (i) their finite size and (ii) the randomness of the location of individual particles in the fluid stream. The results of simulations based on this theory resemble those obtained from experiments.     

浸根法对番茄接种弱毒株(N14)获得的效果

 应用弱毒株保护,对烟草花叶病毒强毒株(TMV-L)侵染番茄形成花叶病,而获得免疫性的研究。国内外试验都取得一定效果。     

Conserving Southeast Asian forest biodiversity in human-modified landscapes

Southeast Asia experiences one of the highest rates of deforestation in the tropics due to agricultural expansion, logging, habitat fragmentation and urbanization, which are expected to result in species declines and extinctions. In particular, growing global demands for food, biofuel and other commodities are driving the rapid expansion of oil palm and paper-and-pulp industries at the expense of lowland dipterocarp forests, further jeopardizing Southeast Asian forest biotas. We synthesize recent findings on the effects of land-use changes on plants, invertebrates, vertebrates and ecosystem functioning/services in Southeast Asia. We find that species richness and abundance/density of forest-dependent taxa generally declined in disturbed compared to mature forests. Species with restricted ranges and those with habitat and foraging specialization were particularly vulnerable. Forest loss also disrupted vital ecosystem services (e.g. crop pollination). Long-term studies are needed to understand biotic sustainability in regenerating and degraded forests, particularly in the context of the synergistic or additive effects of multiple agents of biodiversity loss (e.g. invasive species and climate change). The preservation of large tracts of mature forests should remain the principal conservation strategy in the tropics. In addition, reforestation and reintroductions of native species, as well as improved connectivity among forest patches could enhance the conservation value of forest remnants in human-dominated landscapes.     

六六六土壤施药防治三化螟的试验

牛头天社蛾(Phalera bucephala L.)为新疆維吾尔自治区林业和行道树中最普遍的一种食叶害虫,已見为害的树种有榆、楊、柳,据文献記載尚有樺、櫟、榛、榿、槭、花楸及苹果、梨等树。国外分布于欧洲及西伯利亚;我国仅知于新疆,分布于烏魯木齐、瑪納斯、沙湾等县。成虫体长22—24毫米,翅展50—60毫米。触角双櫛齿状,复眼灰色。顱頂毛棕褐色,頸板毛及前胸背桔黄色,其两側和后緣有由棕褐色鳞毛所組成的带二条。从头部正視之,甚为雄壮,有如牛头,故学名原意称为“牛头”,今以牛头天社蛾名之,有利于記忆学名。前翅銀灰色,在苏联称之为銀色天社蛾。頂角处有一金黄色大圓斑,斑紋内有两条桔黄色較寬的横断綫,与嵌在两边的棕褐色端綫、亚端綫及外綫,形成和头胸部相似的花紋。前翅中央处有一淡黄色小斑。基綫及亚基綫(內綫)亦为棕褐色。后翅黄白色,有一微弱的中     

Sensible consumerism for environmental sustainability

Navjot Sodhi and we often discussed how growing global demands for food are placing increasing pressures on tropical forests. Although more consumers are demanding for ‘greener’ products associated with sustainable production, green consumerism and improved production practices per se might not adequately curtail destruction of forests and biodiversity. Instead, we argue that consumers in emerging and developed countries need to avoid wasteful and excessive consumption. We demonstrate how reasonable recalibration of consumer aspirations and changes in consumption levels in China, India, the European Union and United States might substantially alleviate environmental impacts associated with oilseed production in Indonesia, Malaysia, Brazil and Argentina. We do so through a scenario analysis that projects oilseed demands and expansion from current levels to 2100 under three alternative consumption trends. We show that pursuing a business-as-usual course of consumption would impose severe pressures in producer countries to clear land for oil-palm and soybean agriculture (up to an additional ～12 million hectares by 2040), which could exacerbate rates of deforestation and biodiversity loss in these tropical regions. On the other hand, if each person in the EU and US reduces his/her daily vegetable oil consumption by an average of 25 g – roughly equivalent to forgoing one large serving of French Fries – the pressure to convert tropical forests for oilseed expansion could be reduced by up to ～70%. Our analysis demonstrates how changes in consumer behavior in industrialized nations could substantially alleviate environmental impacts associated with agricultural production in the developing tropics.     

Effects of replacing fish meal with soya protein concentrate on growth,feed efficiency and digestibility in diets for snakehead,Channa striata

Soya bean meal‐based formulated feeds have recently become available for snakehead culture in Vietnam. This study was conducted to determine the appropriate replacement of fish meal (FM) protein by another soya product, soya protein concentrate (SPC), in snakehead (Channa striata) diets. Five iso‐nitrogenous (45% crude protein) and iso‐caloric (19 KJ g^?1) practical diets were formulated to replace 0% (control), 40%, 60%, 80% and 100% of protein FM by protein SPC (100% FM, 40% SPC, 60% SPC, 80% SPC and 100% SPC respectively). A digestibility experiment was also conducted with the same formulated diets with addition of 1% chromic oxide. Fish fed 100% FM and 40% SPC diets had significantly better growth and survival compared with other treatments. Feed intake, feed conversion ratio, protein efficiency ratio and net protein utilization, trypsin and chymotrypsin activities of experimental fish fed 100% FM and 40% SPC diets were significantly higher than those fed other diets. The apparent digestibility coefficient (ADC) of the diet and diet components, ADC_diet, ADC_protein and ADC_lipid, of fish fed diet 40% SPC and 100% FM treatment were significantly higher than those of other treatments. The cost/kg fish produced in diets 100% FM and 40% SPC was much lower compared with other treatments. Dietary inclusion levels of SPC in diet above 40% significantly affected fish survival, growth, digestibility and trypsin and chymotrypsin activities, although fish chemical composition was not greatly affected.     

Comparison of the hypothalamic–pituitary–adrenal axis in MDR1-1Δ and MDR1 wildtype dogs

Objective: To evaluate the hypothalamic–pituitary–adrenal (HPA) axis in MDR1‐1Δ (dogs with the MDR1 mutation associated with ivermectin sensitivity) and MDR1 wildtype dogs. Design: Prospective study. Setting: Institutional vivarium. Animals: Seven healthy Collie dogs. Measurements: MDR1 genotyping was used for allocation of dogs to 1 of 2 groups: dogs homozygous for the wildtype MDR1 allele (MDR1 wildtype) and those homozygous for the MDR1‐1Δ mutation (MDR1 mutant). Blood samples were obtained for determination of cortisol and adrenocorticotropin hormone (ACTH) concentrations under basal conditions, before and after ACTH administration, and before and after dexamethasone administration. Main results: Significant differences were identified between the MDR1 mutant and MDR1 wildtype groups. Basal plasma cortisol concentrations and cortisol concentrations after ACTH administration were significantly lower in MDR1 mutant dogs as compared with MDR1 wildtype dogs. Plasma ACTH concentrations after dexamethasone administration were significantly lower in MDR1 mutant dogs as compared with MDR1 wildtype dogs. Conclusions: Results suggest that P‐glycoprotein (P‐gp) plays a role in regulation of the HPA axis. Furthermore, it appears that the HPA axis in MDR1 mutant dogs that lack P‐gp is suppressed compared with MDR1 wildtype dogs. This finding may explain some clinical observations in breeds known to harbor the MDR1 mutation including Collies, Shelties, Australian Shepherds, and others. There is a clinical impression that many of these dogs have worse outcomes in response to stress and, at times, respond poorly to appropriate therapy. HPA axis suppression, secondary to the MDR1 mutation, could result in a relative adrenal insufficiency (RAI) state during times of stress or illness. Further studies are required to determine the relationship between the MDR1 genotype and RAI.