Mother–child emotion dialogues: the disrupting effect of maternal history of communal sleeping

The study examined associations between mothers’ upbringing background (kibbutz vs. home) and maternal-sensitive guidance of emotional conversations with their preschool children; children’s cooperation and exploration; and the coherence of their conversations. Using a quasi-experimental design, 112 children and their mothers (72 kibbutz raised, 40 home) completed the Autobiographical Emotional Event Dialogue. We hypothesized that maternal kibbutz upbringing would be associated to lower levels of mothers’ sensitive guidance of the conversations, children’s lower cooperation and exploration, and lower overall coherence. Results showed no upbringing-related differences for the mothers, but significant differences were found for the children, with children of kibbutz-raised mothers showing less cooperation and exploration, and lower levels of coherence for these dyads. The role of maternal background in shaping the interaction with their child is discussed.     

The Momentary Relationship Between Stress and Headaches in Adolescent Girls

Objective.— The objective of this study was to compare the relationship between repeated momentary reports of stress and headaches in female adolescents with varying degrees of headache frequency. Background.— Headaches are the most common form of pain reported by adolescents affecting more than a third of all adolescents. High levels of stress during adolescence may predispose an adolescent to experience headaches in adulthood. Randomized, momentary data collection of stress and headaches provides the most accurate data regarding the adolescent experience of these variables. Methods.— The research methodology, ecological momentary assessment, is a valid approach to better understand the relationship between stress and headaches in adolescence. Data were obtained by each participant's use of an electronic diary (ED), which captured repeated momentary reports of perceived stress, head pain, and stress‐related symptoms in female adolescents with varying degrees of recurrent headache. Seven times per day for the 21‐day study period, teen girls responded to ED questions about their current stress levels, head pain, and stress‐related symptoms. Based on participants' momentary reports of headaches, Low Headache, Moderate Headache, and Chronic Headache groups were created. General estimating equation models were used to analyze the relationship between momentary variables as well as the lag effect between stress and head pain. Results.— Thirty‐one participants, aged 14‐18 years, completed 2841 randomized ED reports and reported 674 occurrences of headache. The Chronic Headache and Moderate Headache groups reported significantly increased levels of stress, head pain, and headaches. The relationship between momentary stress and head pain was significantly strong both within and across participants. The strength of this relationship increased with increased headache activity. A significant lag effect was found between stress and headaches; however, the effect of depression as a moderator of the stress and headache relationship remains unclear. Conclusion.— Perceived stress and head pain was highly correlated in these female adolescents. Given the large population of teens affected by headaches, a plausible next step would be to validate these results in other samples and to determine methods with which to identify teens who may be at risk for a pattern of increasing stress and headaches.     

Long prereproductive selection and divergence by depth in a Caribbean candelabrum coral

Long-lived corals, the foundation of modern reefs, often follow ecological gradients, so that populations or sister species segregate by habitat. Adaptive divergence maintains sympatric congeners after secondary contact or may even generate species by natural selection in the face of gene flow. Such ecological divergence, initially between alternative phenotypes within populations, may be aided by immigrant inviability, especially when a long period separates larval dispersal and the onset of reproduction, during which selection can sort lineages to match different habitats. Here, we evaluate the strength of one ecological factor (depth) to isolate populations by comparing the genes and morphologies of pairs of depth-segregated populations of the candelabrum coral Eunicea flexuosa across the Caribbean. Eunicea is endemic to the Caribbean and all sister species co-occur. Eunicea flexuosa is widespread both geographically and across reef habitats. Our genetic analysis revealed two depth-segregated lineages. Field survivorship data, combined with estimates of selection coefficients based on transplant experiments, suggest that selection is strong enough to segregate these two lineages. Genetic exchange between the Shallow and Deep lineages occurred either immediately after divergence or the two have diverged with gene flow. Migration occurs asymmetrically from the Shallow to Deep lineage. Limited recruitment to reproductive age, even under weak annual selection advantage, is sufficient to generate habitat segregation because of the cumulative prolonged prereproductive selection. Ecological factors associated with depth can act as filters generating strong barriers to gene flow, altering morphologies, and contributing to the potential for speciation in the sea.     

Turning back from the brink: Detecting an impending regime shift in time to avert it

Ecological regime shifts are large, abrupt, long-lasting changes in ecosystems that often have considerable impacts on human economies and societies. Avoiding unintentional regime shifts is widely regarded as desirable, but prediction of ecological regime shifts is notoriously difficult. Recent research indicates that changes in ecological time series (e.g., increased variability and autocorrelation) could potentially serve as early warning indicators of impending shifts. A critical question, however, is whether such indicators provide sufficient warning to adapt management to avert regime shifts. We examine this question using a fisheries model, with regime shifts driven by angling (amenable to rapid reduction) or shoreline development (only gradual restoration is possible). The model represents key features of a broad class of ecological regime shifts. We find that if drivers can only be manipulated gradually management action is needed substantially before a regime shift to avert it; if drivers can be rapidly altered aversive action may be delayed until a shift is underway. Large increases in the indicators only occur once a regime shift is initiated, often too late for management to avert a shift. To improve usefulness in averting regime shifts, we suggest that research focus on defining critical indicator levels rather than detecting change in the indicators. Ideally, critical indicator levels should be related to switches in ecosystem attractors; we present a new spectral density ratio indicator to this end. Averting ecological regime shifts is also dependent on developing policy processes that enable society to respond more rapidly to information about impending regime shifts.     

A screening level probabilistic risk assessment of mercury in Florida Everglades food webs

A screening level probabilistic assessment of risks was performed on three species of piscivorous wildlife at the top of Everglades aquatic food webs: the American alligator (Alligator mississippiensis), the great egret (Egretta alba), and the raccoon (Procyon lotor varius). Ranges of dietary exposure concentrations (and probability distribution functions) were derived for two general areas of the Everglades: Shark Slough and the southcentral Everglades (highly contaminated with Hg), and the northern Everglades (a lower Hg contaminated area in and near Water Conservation Area 1). Ranges of toxicity reference values and probability distribution functions were derived from literature on the toxicity of dietary methyl Hg to birds and mammals. Probability distributions of risk estimates for each receptor were generated using Monte Carlo simulations and indicated that piscivorous wildlife feeding in the south-central region of the Everglades are at high risk from consumption of Hg-contaminated prey. Alligators had 100% exceedences of chronic risk thresholds, and great egrets had 99% exceedences. In the northern Everglades, exceedences of chronic risk thresholds were substantially lower but were still present (6-34% exceedences). Results support previous studies suggesting that top predators of the Everglades may be at risk from Hg contamination and indicate that Hg risks are location-dependent.     

Methadone maintenance treatment,criminality and overdose-related deaths. An ecological study, 1983-1999

BACKGROUND: Methadone maintenance treatments (MMTs) are the commonest substitution treatments offered to opiate addiction in Switzerland, in order to reduce criminal behaviour, infectious disease transmission and overdose death. METHOD: To investigate the relationship between the increase in the number of methadone maintenance treatments, criminal activity of addicts and overdose-related deaths, an ecological study was undertaken in the Canton of Geneva, from 1983 to 1999. RESULTS: The regular and extensive increase in the number of MMTs is not significantly associated, during the 1983-1999 period, with a fall either in drug addict incarcerations or in overdose-related deaths. However, a slight decrease is observed in the number of imprisoned opiate addicts since 1994, and a marked decrease is seen in overdose deaths from 1997 on. An important and stable number of these deaths is due to methadone itself. CONCLUSION: Public health objectives to diminish delinquency and overdose deaths cannot solely be fulfilled by extensive use of MMTs. A positive result could appear when access to MMT is highly favoured. This hypothesis must be proved correct by observational studies conducted on a general population.     

Effects of a mixture of two insecticides in freshwater microcosms: I. Fate of chlorpyrifos and lindane and responses of macroinvertebrates

Effects of chronic application of a mixture of the insecticides chlorpyrifos and lindane were studied in indoor freshwater microcosms. The exposure concentrations (based on 0, 0.005, 0.01, 0.05, 0.1 and 0.5 times the LC50 of the most sensitive standard test organism for each compound) were kept at a constant level for four weeks. The calculated mean concentrations for chlorpyrifos were found to be almost at their corresponding nominal level during the treatment period. The mean calculated lindane concentrations, however, were found to be 15–40% higher than intended. In the post treatment period both insecticides dissipated fast (t _1/2: chlorpyrifos 9 days, lindane 22 days) from the water phase. The concentrations of the mixture at the highest treatment level corresponded to 0.53 toxic units (TU) for Daphnia magna and 0.61 TU for the most sensitive fish. The decomposition of Populus leaves in litter bags was significantly lower at the three highest insecticide concentrations. The macroinvertebrate community was seriously affected at the three highest treatment levels, with Crustacea and the Chironomidae Corynoneura proving to be the most sensitive groups. Gastropoda and Oligochaeta were relatively insensitive and some taxa (e.g. Valvata piscinalis, juvenile Physa fontinalis, Nemertea and Stylaria lacustris) increased in numbers. The observed effects could be explained from the individual toxicity of the insecticides to the invertebrates, and did not indicate synergistic effects. A second paper (Van den Brink et al., 2002) addresses the effects on other endpoints, as well as the overall risk assessment of the insecticide mixture.     

Effects of a mixture of two insecticides in freshwater microcosms: II. Responses of plankton and ecological risk assessment

This paper reports on the chronic effects of a mixture of the insecticides chlorpyrifos and lindane in freshwater microcosms. Chronic treatment levels corresponding to concentrations of 0, 0.005, 0.01, 0.05, 0.1 and 0.5 times the LC50 of the most sensitive standard test organism were evaluated. The zooplankton community structure was altered from the 0.05*LC50 treatment level upwards. Cladocerans were the most susceptible group, followed by Copepoda and Ostracoda. Rotifera increased in abundance at the higher treatment levels. Increased abundance of some phytoplankton taxa and increased chlorophyll-a levels were found at the two highest treatment levels, most probably a consequence of decreased grazing pressure. Threshold levels for the mixture, both at population and community/ecosystem level, corresponded well with those reported in the literature for the individual compounds. The overall risk assessment indicates no antagonistic or synergistic effects of the mixture at ecosystem level. It was found that the safety factors set by the Uniform Principles for individual compounds also ensure protection against chronic exposure to a mixture of insecticides at community level, though not always at species level.     

制药用水中总有机碳测定仪的系统适用性试验研究

目的:测试TOC-VCSH型总有机碳分析仪是否符合系统适用性试验要求。方法:采用高温氧化法,分别测定易氧化物与难氧化物的仪器响应值,计算响应效率,以考察仪器的氧化能力和系统的适用性。结论:经测定,TOC -VCSH型总有机碳分析仪符合系统适用性试验要求,可以用于制药用水中总有机碳含量的测定。     

应用模糊数学方法进行黄连引种适栽区划的研究

本文应用模糊数学方法,选择与黄连生物学特性有较大关系的气候生态因子,对我国黄连引种栽培提出适栽区划,以减少黄连等药用植物的盲目引种。