Exposure to odors from stressed conspecifics increases preference for higher ambient temperatures in C57BL/6J mice

Exposure to odors from stressed conspecifics increases preference for higher ambient temperatures in C57BL/6J mice. C57BL/6J male mice were individually allowed preferences on a thermal gradient ranging in temperature from 22°C to 42°C. Group 1 (N=10) was exposed to odors from triads of foot-shocked conspecifics during the first 2-hr temperature preference trial. Group 2 (N=10) was exposed to odors from triads of nonstressed conspecifics during similar testing. Body temperature (T_B) variations were measured in three animals of each group. Thermal preference was significantly higher for animals exposed to odors from stressed conspecifics than for animals exposed to odors from nonstressed animals (32.0°C vs. 29.0°C).T _B changes on the heated gradient were significantly higher for animals exposed to odors from stressed animals (+1.5°C) than for animals exposed to odors from nonstressed animals (–0.33°C). Additional animals on a non-heated thermogradient were tested for T_B when exposed to odors from stressed or from nonstressed animals (N=3 per condition). There was no difference inT _B between these two groups. Increases in T_B on the heated gradient are apparently due to the higher ambient temperature choices and not due to the odor per se.     

Comparative study of hermit crab responses to shell-related chemical cues

The responses of Australian hermit crabs to two types of shell-related odor cues were compared. Introduction of gastropod snail odor elicited an increase in grasping of shells in all four species tested (Clibanarius infraspinatus, C. taeniatus, C. virescens, andDiogenes avarus). However, the magnitude of response in the case ofC. virescens was significantly lower than the responses of individuals of the other species. Individuals ofC. infraspinatus responded to introduction of conspecific hemolymph with an increase in both locomotion and the frequency of grasping of shells.C. infraspinatus also responded to the hemolymph of the other three species, and there were no differences in the magnitude of the responses depending upon the source of the hemolymph. When individuals ofC. infraspinatus were exposed to snail odor and conspecific hemolymph at the same time, the responses were indistinguishable from those shown to hemolymph alone.     

Conditioned behavioral responses to a context paired with the predator odor trimethylthiazoline.

Contextual fear conditioning is the learning of a fear response in a specific context in response to repeated application of aversive stimuli (e.g., foot shocks) or danger-related stimuli (predator odors) within that context. Cat odor, a danger-related stimulus common in laboratory studies of fear in the past, has often been replaced recently with trimethylthiazoline (TMT), a component of fox feces. No contextual fear conditioning in response to TMT has been reported so far, whereas cat odor has often been shown to induce such fear conditioning in rats. Using TMT in both a 1-compartment and a 2-compartment setup, the authors found conditioned fear behavior (expressed as avoidance behavior) in the 2-compartment setup but not--as reported by others--in the 1-compartment setup. Detailed analysis revealed 2 different coping strategies in the 2-compartment setup: Half of the rats showed pronounced avoidance behavior, whereas the other half showed intense risk assessment behavior. These results indicate that expression of conditioned fear behavior in response to a TMT-paired context is dependent on the experimental setup used, as well as the strategy of the individual rat. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Identification of Volatile Potato Sesquiterpenoids and Their Olfactory Detection by the Two-spotted Stinkbug Perillus bioculatus

The predaceous stinkbug Perillus bioculatus is attracted towards volatiles emitted by damaged potato plants. Whereas mechanically damaged plants lost attractiveness 1 h after damage was inflicted, attraction was long-lasting when the plants were damaged by Colorado potato beetles Leptinotarsa decemlineata, a prey of P. bioculatus. A range of sesquiterpenoids was previously shown to be induced upon beetle damage. In order to evaluate the potential role of sesquiterpenoids in the attraction response, volatiles from damaged potato plants were collected and analyzed with GC-MS and GC-EAG. The antennae of P. bioculatus responded to -caryophyllene, -humulene, (E)--farnesene, (–)-germacrene D, and germacrene D-4-ol. Two sesquiterpenes that coeluted, -zingiberene and bicyclogermacrene, together also elicited olfactory responses of P. bioculatus, whereas the individual compounds did not. The response of P. bioculatus to a variety of sesquiterpenes at low dosages suggests a role for these compounds in prey detection of this stinkbug.     

一类捕食-食饵模型正解的存在性和稳定性

研究了一类受顶级掠食者出现影响的捕食-食饵模型正平衡态解的存在性.利用分歧理论及度理论等方法,给出了局部分歧解存在的充分条件,将局部分歧解延拓为全局分歧解,给出分歧曲线随参数的整体走向,同时判定了局部分歧解的稳定性.     

Do some evaluators report consistently higher or lower PCL-R scores than others? Findings from a statewide sample of sexually violent predator evaluations.

This study examined whether some evaluators tend to report consistently higher or lower scores than other evaluators for offenders on the Psychopathy Checklist-Revised (PCL-R; R. D. Hare, 1991, 2003). Data for the study were PCL-R total scores for 321 sex offenders, evaluated by 1 or more of 20 different state-contracted evaluators, during a process of screening for civil commitment as sexually violent predators. More than 30% of the variability in PCL-R scores was attributable to differences among evaluators, with mean PCL-R scores given by 2 of the most prolific evaluators differing by almost 10 points. In a subsample of 22 offenders evaluated with the PCL-R on 2 or more occasions, evaluator agreement (intraclass correlation A,1 = .47) was low. Together, these findings raise concerns about the field reliability of the PCL-R and suggest the need for research examining field reliability of other measures used in forensic assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hard Clams (Mercenaria mercenaria) Evaluate Predation Risk Using Chemical Signals from Predators and Injured Conspecifics

Hard clams, Mercenaria mercenaria, are sessile, filter-feeding organisms that are heavily preyed upon by blue crabs, which find their clam prey using chemical cues. Clams may evade blue crabs by reducing their pumping (feeding) behavior when a threat is perceived. The purpose of this study was to determine the type of signals that clams use to detect consumers. Clams decreased their pumping time in response to blue crabs and blue crab effluent, but not to crab shells, indicating that chemical signals and not mechanical cues mediated the response of clams to distant predators. Because predator diet can influence prey evaluation of predatory threats, we compared clam responses to blue crabs fed a steady diet of fish, clams, or that were starved prior to the experiment. In addition, we used injured clams as a stimulus because many organisms detect predators by sensing the odor of injured con- or heterospecifics. Clams reduced feeding in response to injured conspecifics and to blue crabs that had recently fed. Clams reacted similarly to fed crabs, regardless of their diet, but did not respond to starved blue crabs. Because blue crabs are generalist predators and the threat posed by these consumers is unrelated to the crab's diet, we should expect clam reactions to blue crabs to be independent of the crab's diet. The failure of clams to react to starved blue crabs likely increases their vulnerability to these consumers, but clam responses to injured conspecifics may constitute a strategy that allows animals to detect an imminent threat when signals emanating from blue crabs are not detectable.     

污水处理厂生物过滤除臭技术研究

随着污水厂周边环境要求的提高,对污水厂进行除臭处理成为业界关注的焦点。介绍了污水处理厂恶臭物质的成分、来源和危害。分析了各种除臭方法的工艺特点,主要论述了生物过滤除臭技术的原理及其设计运行参数。     

Crayfish assemblages correlate with dam-induced effects on abiotic factors and predatory fish assemblages in Alabama streams

Stream faunal assemblage structure is tied closely to hydrology and associated physiochemical properties. By altering natural flows, dams and their impoundments impact faunal assemblages over long distances. Although numerous studies have assessed the effect of dams on stream fauna, information is lacking for crayfishes. In this study, we characterized the effects of relatively large storage dams on crayfish assemblage structures. Over 2 years, we sampled three impounded and two unimpounded streams across two drainages in Alabama, United States, to identify biotic and abiotic factors correlated with crayfish assemblage metrics. Compared to impounded streams, unimpounded streams had greater habitat complexity (e.g., aquatic vegetation and woody debris), fewer predator fishes, lower minimum temperatures, and more variable discharges. These characteristics correlated with a higher density and diversity of crayfishes and smaller adults in impounded compared to unimpounded streams. Crayfish species assemblages differed between drainages, as did the biotic and abiotic factors affecting crayfish assemblages in each drainage, suggesting that these factors were species-specific in their effects. Additionally, analysis of land uses suggested that factors other than dams may have also contributed to the observed differences in assemblage structures between impounded and unimpounded streams. For instance, in the more urbanized drainage, crayfish assemblages were more similar between up and downstream sections in all streams, regardless of impoundment. Our results indicate that large dams alter stream crayfish assemblage structure, with potentially cascading effects in trophic and organic matter dynamics both up and downstream.