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Persistent Effects (persistent + effects)
Selected AbstractsPersistent effects of a discrete warming event on a polar desert ecosystemGLOBAL CHANGE BIOLOGY, Issue 10 2008J. E. BARRETT Abstract A discrete warming event (December 21, 2001,January 12, 2002) in the McMurdo Dry Valleys, Antarctica, enhanced glacier melt, stream flow, and melting of permafrost. Effects of this warming included a rapid rise in lake levels and widespread increases in soil water availability resulting from melting of subsurface ice. These increases in liquid water offset hydrologic responses to a cooling trend experienced over the previous decade and altered ecosystem properties in both aquatic and terrestrial ecosystems. Here, we present hydrological and meteorological data from the McMurdo Dry Valleys Long Term Ecological Research project to examine the influence of a discrete climate event (warming of >2 °C) on terrestrial environments and soil biotic communities. Increases in soil moisture following this event stimulated populations of a subordinate soil invertebrate species (Eudorylaimus antarcticus, Nematoda). The pulse of melt-water had significant influences on Taylor Valley ecosystems that persisted for several years, and illustrates that the importance of discrete climate events, long recognized in hot deserts, are also significant drivers of soil and aquatic ecosystems in polar deserts. Thus, predictions of Antarctic ecosystem responses to climate change which focus on linear temperature trends may miss the potentially significant influence of infrequent climate events on hydrology and linked ecological processes. [source] Persistent effects of a pedagogical device targeted at prevention of severe hypoglycaemia: A randomized, controlled studyACTA PAEDIATRICA, Issue 10 2005Sam Nordfeldt Abstract Aim: To study the long-term use of self-study material in type 1 diabetes patient education targeted at the prevention of severe hypoglycaemia. Methods: Randomized 1,1,1 control study in three local hospitals. We studied 332 type 1 diabetes patients from the geographic population, aged 2.6,18.9 y at entry. The intervention group received a videotape and brochure in which interviewed patients, parents and medical experts reviewed in detail practical skills for self-control and treatment, with the aim of preventing severe hypoglycaemia. There were two control groups: one received a videotape and brochure with general diabetes information and the other only traditional treatment. Primary endpoints were severe hypoglycaemia needing assistance by another person and HbA1c. Dissemination, reading/viewing level, patients' attitudes and extra contact with caregivers were also investigated. At 24 mo, 249 subjects provided data. Results: The yearly incidence of severe hypoglycaemia decreased at 24 mo from 42% to 25% (difference 17%, 95% CI 3,31, p=0.0241) in the intervention group, but not in controls. HbA1c remained unchanged. Video use during months 13,24 was higher in the intervention group than in controls (p=0.0477), ranging from 1,15 (median 2) times, among 37% of patients (months 1,12, 100%). Higher future use was anticipated for intervention material (p=0.0003). Extra caregiver contact was related to severe hypoglycaemia (p=0.0009). The cost of the material was Comparison of the effects of early handling and early deprivation on maternal care in the ratDEVELOPMENTAL PSYCHOBIOLOGY, Issue 4 2001Christopher R. Pryce Abstract It has been reported in the rat that postnatal manipulations can induce robust and persistent effects on offspring neurobiology and behavior, mediated in part via effects on maternal care. There have, however, been few studies of the effects of postnatal manipulations on maternal care. Here, we describe and compare the effects on maternal behavior on postnatal days 1,12 of two manipulations, early handling (EH, 15-min isolation per day) and early deprivation (ED, 4-hr isolation per day), relative to our normal postnatal husbandry procedure. Maternal behavior was measured at five time points across the dark phase of the reversed L:D cycle. EH yielded an increase in arched-back nursing across several time points but did not affect any other behavior. ED stimulated a bout of maternal behavior such that licking and arched-back nursing were increased at the time of dam,litter reunion, although not at any other time point. Neither EH nor ED affected weaning weight significantly. Importantly, within-treatment variation was high relative to these between-treatment effects. © 2001 John Wiley & Sons, Inc. Dev Psychobiol 38: 239,251, 2001 [source] Comparing strategies for controlling an African pest rodent: an empirically based theoretical studyJOURNAL OF APPLIED ECOLOGY, Issue 5 2001Nils Chr. Summary 1Small rodents in general and the multimammate rat Mastomys natalensis in particular cause major economic losses in Africa through damage to crops. Attempts to develop dynamic population models for this and other pest rodents are ongoing. 2Demographic estimates from a capture,mark,recapture (CMR) study in Tanzania were used to parameterize a population model for this species. This model incorporated three functional age categories (juveniles, subadults and adults) of both sexes and used density-dependent and density-independent factors, the latter represented by rainfall. 3The model was used to analyse the effect of rodent control on the population dynamics and resulting number of rats. Control measures affecting survival as well as reproduction were considered. 4The model showed that control measures reducing survival will only have long-term effects on population size if they are also applied when rodent densities are low. Control measures applied only when rodent densities are high will not have persistent effects, even at high mortality rates. 5The model demonstrated that control measures reducing reproduction are likely to prevent Mastomys outbreaks, but will keep densities low over a long period only when the contraceptive effect is strong (> 75% reduction). 6Provided that CMR data are available, we recommend developing Leslie-type population models for rodent pests on the basis of CMR-estimated demographic schedules. Such models have great potential in rodent management and allow the evaluation of different strategies. 7Besides improving the ecological basis of the population modelling, economic considerations need to be incorporated into decisions about rodent control. We suggest that appropriate population models will provide important input into such decision making. [source] Effects of the past and the present on species distribution: land-use history and demography of wintergreenJOURNAL OF ECOLOGY, Issue 2 2000Kathleen Donohue Summary 1,Past land use can have long-term effects on plant species' distributional patterns if alterations in resources and environmental conditions have persistent effects on population demography (environmental change) and/or if plants are intrinsically limited in their colonization ability (historical factors). 2,We evaluated the role of environmental alteration vs. historical factors in controlling distributional patterns of Gaultheria procumbens, a woody, clonal understorey species with a pronounced restriction to areas that have never been ploughed, and near absence from adjoining areas that were ploughed in the 19th century. The demographic study was conducted in scrub oak and hardwood plant communities on an extensive sand plain, where it was possible to control for the effect of variation in environment prior to land use. 3,The observed demographic effects were contrary to the hypothesis that persistent environmental alteration depressed demographic performance and limited the distribution of G. procumbens. We observed no overall effect of land-use history on stem density, stem recruitment or flower production. In fact, some aspects of performance were enhanced in previously ploughed areas. Populations in previously ploughed areas exhibited less stem mortality in scrub oak transitions, an increase in germination, seedling longevity and proportion of potentially reproductive stems in both plant communities, a trend for slower observed rates of population decline in both plant communities, and a higher projected rate of population growth in the scrub oak transitions. Thus, particularly in scrub oak communities, the lower abundance of G. procumbens in formerly ploughed than in unploughed areas contrasted with its performance. 4,The limited occurrence of G. procumbens in formerly farmed areas was explained instead by its slow intrinsic growth rate, coupled with limited seedling establishment. Lateral population extension occurred exclusively through vegetative growth, allowing a maximum expansion of 43 cm year,1. 5,We conclude that inherent limitations in the colonizing ability of some plant species may present a major obstacle in the restoration or recovery of plant communities on intensively disturbed sites, even in the absence of persistent environmental effects that depress population growth. [source] Psychoeducation for Survivors of TraumaPERSPECTIVES IN PSYCHIATRIC CARE, Issue 3 2007Bethany J. Phoenix RN PURPOSE.,Education about the persistent effects of trauma helps survivors better understand their own stress responses, and knowledge of coping strategies provides a sense of control over these responses. Trauma education for providers can minimize negative countertransference and prevent vicarious traumatization. CONCLUSIONS.,This article discusses content areas to be covered in psychoeducation with survivors of acute traumatic events and prolonged trauma and abuse, and reviews resources for trauma psychoeducation with clients and healthcare providers. PRACTICE IMPLICATIONS.,Advanced practice psychiatric nurses may provide psychoeducation to people who suffer from complex psychological and behavioral disturbances related to severe and persistent abuse or trauma, especially early in life. [source] Labour characteristics and uterine activity: misoprostol compared with oxytocin in women at term with prelabour rupture of the membranesBJOG : AN INTERNATIONAL JOURNAL OF OBSTETRICS & GYNAECOLOGY, Issue 2 2000Suk Wai Ngai Assistant Professor Objective To compare the labour pattern and uterine activity of oral misoprostol with oxytocin for labour induction in women presenting with prelabour rupture of membranes at term. Design Prospective randomised study. Setting Department of Obstetrics and Gynaecology, Queen Mary Hospital, Hong Kong. Participants Eighty women presenting with prelabour rupture of membranes at term. Methods The women were randomised to receive either 100 ,g misoprostol orally every 4 hours to a maximum of three doses, or intravenous oxytocin infusion according to the hospital protocol. Intrauterine pressure transducers were inserted one hour before induction of labour in both groups of women. We compared the pattern of uterine activity, the induction-to-delivery interval, duration of labour, mode of delivery and neonatal outcome between the two groups. Results Both oxytocin and oral misoprostol caused an increase in uterine activity within one hour of labour induction. Peak uterine activity was reached 6,8 h after oral misoprostol, with persistent effects, and 8,10 h after oxytocin, requiring continuous titration of medication. The duration of labour was significantly reduced in nulliparous women, but not in those who were multiparous in the misoprostol group. The induction-to-delivery interval, the mode of delivery and the perinatal outcome were similar for the two groups. Conclusion Oral misoprostol caused earlier peak uterine activity, compared with oxytocin (6,8 h vs 8,10 h). Oral misoprostol was not only as effective as oxytocin in inducing labour in women at term with prelabour rupture of the membranes, but it reduced significantly the duration of labour in nulliparous women. [source]
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