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1.
Autopsy investigations provide valuable information regarding fetal death that can assist in the parental bereavement process, and influence future pregnancies, but conventional autopsy is often declined by parents because of its invasive approach. This has led to the development of less-invasive autopsy investigations based on imaging technology to provide a more accessible and acceptable choice for parents when investigating their loss. Whilst the development and use of more conventional clinical imaging techniques (radiographs, CT, MRI, US) are well described in the literature for fetuses over 20 weeks of gestational age, these investigations have limited diagnostic accuracy in imaging smaller fetuses. Techniques such as ultra-high-field MRI (>3T) and micro-focus computed tomography have been shown to have higher diagnostic accuracy whilst still being acceptable to parents. By further developing and increasing the availability of these more innovative imaging techniques, parents will be provided with a greater choice of acceptable options to investigate their loss, which may in turn increase their uptake. We provide a narrative review focussing on the development of high-resolution, non-invasive imaging techniques to evaluate early gestational pregnancy loss.  相似文献   

2.
The reactions of women who had had a termination of pregnancy for fetal abnormality in the second trimester have been studied retrospectively using a semi-structured questionnaire. The severity of the grief reaction was measured and the outcome at 6months was compared with the findings from a previous study in South Wales which had led to the introduction of skilled support from genetic fieldworkers and formal genetic counselling after the termination. Of the 69 women interviewed, 55 (80 per cent) experienced an acute grief reaction and 17 (25 per cent) had not resolved their grief 6 months after the termination, compared with 37 (77 per cent) and 22 (46 per cent) out of 48 respectively in the previous study. Fifty-seven (83 percent) women had found the fieldworker's intervention useful or very useful, some describing her support as essential. An association between poor resolution of the grief reaction with increasing maternal age and with poor perceived support from partners was noted. Improved follow-up support and counselling have lessened the adverse emotional consequences and support should therefore be offered to all women undergoing termination for fetal malformation.  相似文献   

3.
We studied the emotional reactions of 41 women in late pregnancy shortly after they had been informed of the diagnosis of ‘severe or lethal fetal malformations’ and 3 months after delivery. In addition, situational variables were explored as determinants of grieving. While grief did not diminish during the study period, psychological instability was less pronounced at 3 months after delivery. More grief reactions were evoked by self-reported easily versus self-reported not easily initiated pregnancy, gestational age between 24 and 34 weeks versus beyond 34 weeks, multiparity versus primiparity, and viewing versus not viewing the baby.  相似文献   

4.
In animals, mate-choice is often based on sexual signals that carry information and help the receiver make the best choice to improve the receiver’s fitness. Orange visual sexual signals have been hypothesised to carry immune information because they are often due to carotenoid pigments which are also involved in immunity response. Although many studies have focused on the direct relationships between coloration and immunocompetence, few studies have simultaneously studied immunocompetent response and coloration variation after an immune challenge. We tested this hypothesis on starved and ad libitum-fed males of the European tree frog Hyla arborea. Our results show that male coloration is not a reliable indicator of its immune response capacity in this species. However, after an immune challenge induced by a PHA (Phaseolus vulgaris phytohaemagglutinin) injection, starved males presented a significant coloration loss and this alteration was related to the immune response intensity. Taken together, these results suggest that the brighter (lighter) coloration may be used as a cue by female to exclude males with a recent immune challenge, due to diseases or parasites for example.  相似文献   

5.
Couples expecting twins are often unrealistically optimistic and are therefore unprepared for the complications as well as the practical and emotional impact the birth of twins can have on the family. All such couples will need information and support throughout the pregnancy and beyond. In this review, the various aspects that should be addressed are discussed, in particular, health care workers and counsellors need to be aware of the stress experienced by parents who have been through prolonged treatment for infertility or who face the special problems associated with the loss of one twin (implies the loss could be other than death). Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

6.
This paper reports results of an exploratory study of prenatal diagnosis patients who experienced voluntary terminations of pregnancy following the detection of an abnormality or spontaneous miscarriages. The 121 participants were part of the national collaborative Chorionic Villus Sampling and Amniocentesis Study. They completed semi-structured telephone interviews and mailed questionnaires at 1 month and 6 months after the pregnancy losses. Scores on the Profile of Mood States showed that mood levels improved significantly over time. However, there were some declines in loss-related support from partners and others. The persisting distress and difficulties of a minority highlight the variability in women's responses to pregnancy losses. Women who lost pregnancies later in gestation, showed the greatest mood disturbances at initial assessments, used professional mental health assistance after the loss, or reported less satisfactory loss-related support from significant others showed the greatest levels of mood disturbance at the six-month assessment. Follow-up contacts with patients who lose pregnancies should be used to inform women about the variation in possible grief reactions, to assess the extent of support the women are receiving from their partners and significant others, and to provide additional follow-up or referral of those experiencing the greatest distress.  相似文献   

7.
Artificial manipulations of habitat, such as those that incorporate adding nesting boxes or platforms for birds, often enhance the breeding success of threatened animals. However, such alterations are likely to have unintended behavioral and ecological effects that might negatively impact the target species or others in its community. We conducted a controlled study to investigate the effect of artificial nesting platforms on aggressive behavior and reproductive success of male common loons (Gavia immer). Males residing on territories to which platforms were added produced longer territorial "yodels" (reflecting willingness to escalate a contest), experienced increased levels of confrontation and aggression with territorial intruders, and experienced increased rates of territorial displacement by intruders. Surprisingly, males of treatment territories also experienced lower productivity. Therefore, in addition to providing novel empirical support of sequential assessment models of animal contests that predict contest escalation with increasing resource quality, this study is one of a few to show that tools used to mitigate habitat loss can negatively impact reproductive fitness in a threatened species.  相似文献   

8.
孙昭安  朱彪 《环境科学》2023,44(12):6857-6868
已有研究表明除了作物碳(根际沉积碳和秸秆碳)对农田土壤有机碳(SOC)的输入外,土壤碳还来源于土壤自养微生物固定SOC的贡献以及土壤无机碳(SIC)的固定(无机化学途径和微生物的生物矿化途径).农田SOC的高低主要受到外源作物碳输入和原有SOC分解的平衡作用.作物碳输入在短期内通常促进SOC的分解,呈现正(根际)激发效应.通过整合分析主要作物的根际激发效应和秸秆还田的激发效应的研究,发现作物根系生长和秸秆还田引起的(根际)激发效应大小平均值分别为75%和67%.尽管秸秆还田通过激发效应引起SOC分解的额外释放,但是土壤残留秸秆碳通常大于激发效应导致SOC的额外损失,因此秸秆还田可能增加SOC的储量.在农田系统中,秸秆碳和根际沉积碳往往共存,这导致土壤碳输入和输出至少有3个碳源(根际沉积碳、秸秆碳和土壤碳),由于多碳源体系的区分方法存在挑战,目前这两种作物碳(根际沉积碳和秸秆碳)对SOC分解的激发效应影响是不清晰的.最后,提出了新量化方法,可以多源区分根际CO2排放以及SOC中作物碳输入的碳源,以及区分碱性土壤中无机化学和微生物途径对SIC的贡献.研究有助于提高对农田土壤SOC和SIC输入和输出途径的理解,以及农田土壤碳平衡评估的精确度.  相似文献   

9.
Numerous studies have focussed on the relationship between female choice and the multiple exaggerated sexual traits of males. However, little is known about the ability of males to actively enhance specific components of their display in response to the loss of one component. We investigated the capacity of male satin bowerbirds (Ptilonorhynchus violaceus) to respond to the loss of one of their sexual signals by performing an experiment in which we removed decorations at their bowers. We found that males compensated for decoration loss by increasing bower construction behaviour and decreasing their latency to bower painting. These results are novel because they suggest that males can assess the quality of their own display and make decisions about how to augment their displays. We discuss these results in the context of previous studies of mate choice in satin bowerbirds, as both of the supplementary behaviours we observed are known correlates of male mating success.  相似文献   

10.
受资源禀赋的约束,减少粮食产后损失日益成为增加粮食供给、保障粮食安全的重要措施之一。论文采取实地测量的方法,在全国5省6地开展田间实验和调查访谈,考察了水稻收获环节的损失情况。结果显示:各实验地块水稻收获环节的损失率为1.18%~6.55%。其中,水稻联合收获的损失率显著高于分段收获,先进机型收获的损失率低于普通机型,田地湿度、倒伏程度与水稻收获环节的损失率正相关。结合水稻优势区域的分布推算,全国水稻收获环节的损失率为3.02%。减损的情景模拟表明,当全国水稻收获环节的损失率下降到2.76%(根据农业部《水稻机械化生产技术指导意见》测算),可节约稻谷54万t,可供439万人消费1 a,相当于节约耕地7.84万hm2,化肥2.61万t(折纯)。  相似文献   

11.
空气污染严重危害公众健康及社会可持续发展,空气污染的健康经济损失评价是环境相关部门开展成本-效益分析的基础.为理清研究现状,为后续研究提供参考,从空气污染健康经济损失的评价对象、评价方法以及空气污染因子的选择对文献进行了分析.结果表明:健康经济损失评价的热点对象主要集中在我国等空气污染较严重的新兴经济体国家,得益于我国监测数据的日趋完善,运用连续多年数据评价区域健康经济损失动态变化的研究开始增多.评价中经常采用的方法有人力资本法、修正人力资本法、患病失能法、支付意愿法、疾病成本法、统计寿命价值法、情景分析法等,每种方法有各自的适用范围与优缺点,评价中常综合使用多种方法以提高结果的可靠性.评价使用的空气污染因子已由SO2、CO为主,逐渐转向以PM10与PM2.5为主、O3为辅,加强PM2.5、O3、CO2的协同治理已经成为共识,并在部分区域付诸实施.研究显示,空气污染的健康经济损失评价领域涉及内容较广,需要多学科研究人员的参与以提高研究质量及促进学科交叉融合.   相似文献   

12.
云南玉龙山东南坡降雨因子与土壤流失关系的研究   总被引:13,自引:0,他引:13  
水土流失做为破坏生态环境、阻碍工农业生产、限制自然资源优势发挥的重要因素之一,是我国大部分地区生态环境系统中所面临的突出问题。本文以1985年云南玉龙雪山东南坡水土流失定点观测的实测数据为依据,着重定量分析了水土流失与其主要影响因子一降雨之间的关系。通过对比研究,阐述了不同降雨特征值对流失土量的影响,提出了雨强递减系数这一新的降雨影响因子。  相似文献   

13.
粮食损失研究进展和展望   总被引:1,自引:0,他引:1  
我国人多地少,粮食安全事关国家安全。因此,在重视增产的同时,需要不断关注粮食损失问题。通过回顾现有粮食损失的研究,总结文献中提出的重要问题,展望未来可能的研究方向。分析表明,现有研究主要集中在:(1)减少粮食损失的目的和效果的研究。包括增加粮食供给、保障国家安全,减少不必要的资源浪费、减轻环境压力,保障粮食质量、保证食品安全,以及增加粮食价值链参与者的利润等。(2)粮食产后各环节损失水平估计及其影响因素研究。 (3)减少粮食损失的方法研究,包括品种改良、教育培训、改进储存设施等。在对现有研究综述的基础上,提出了几点展望:未来的研究应向粮食价值链下游环节拓展,对粮食质量损失程度进行定量分析,并关注粮食的最优损失水平。  相似文献   

14.
农地的生态系统服务对人类的可持续发展有着重要的意义,而该系统的部分生态价值因未在市场上反映出来而往往被人类所忽略,本文在农地非农化过程中关于损失的生态价值方面进行总结,从研究方法、内容等方面总结了现有研究的特点,从生态服务价值的揭示程度、研究视角的广泛程度、研究方法的完善程度等方面分析了国内研究中存在的基本问题,为今后的研究提供理论依据。  相似文献   

15.
Running is essential in all terrestrial animals mainly for finding food and mates and escaping from predators. Lizards employ running in all their everyday functions, among which defense stands out. Besides flight, tail autotomy is another very common antipredatory strategy within most lizard families. The impact of tail loss to sprint performance seems to be species dependent. In some lizard species, tail shedding reduces sprint speed, in other species, increases it, and, in a few species, speed is not affected at all. Here, we aimed to clarify the effect of tail autotomy on the sprint performance of a cursorial lizard with particular adaptations for running, such as bipedalism and spike-like protruding scales (fringes) on the toepads that allow high speed on sandy substrates. We hypothesized that individuals that performed bipedalism, and have more and larger fringes, would achieve higher sprint performance. We also anticipated that tail shedding would affect sprint speed (though we were not able to define in what way because of the unpredictable effects that tail loss has on different species). According to our results, individuals that ran bipedally were faster; limb length and fringe size had limited effects on sprint performance whereas tail autotomy affected quadrupedal running only in females. Nonetheless, tail loss significantly affected bipedalism: the ability for running on hindlimbs was completely lost in all adult individuals and in 72.3% of juveniles.  相似文献   

16.
The display of female traits by males is widespread in the animal kingdom. In several species, this phenomenon has been shown to function adaptively as a male mating strategy to deceive sexual rivals (female mimicry). Freshly emerged males of the parasitic wasp Lariophagus distinguendus (Hymenoptera: Pteromalidae) are perceived by other males as if they were females because of a very similar composition of cuticular hydrocarbons which function as a sex pheromone in this species inducing courtship behaviour in males. Within 32 h, however, males deactivate the pheromone and are no longer courted by other males. In this paper, behavioural experiments were performed to test hypotheses on potential costs and benefits associated with the female odour in young males. We did not find any benefits, but demonstrated that young males were significantly more often outrivaled in male-male contests when competing with two older males for a female. Also, young males were significantly more often mounted in homosexual courtship events during these contests. Thus, display of female traits by males is not necessarily beneficial, and in fact, can be disadvantageous. We suggest that these costs have favoured the evolution of the pheromone deactivation mechanism in L. distinguendus males. The function of cuticular hydrocarbons as a female courtship pheromone in L. distinguendus might have evolved secondarily from a primary function relevant for both genders, and the deactivation of the signal in males might have caused a shift of specificity of the chemical signal from the species level to the sex level.  相似文献   

17.
Here we use sexual selection theory to develop a logistically simple, yet effective, method for the manipulation of female reproductive behavior for conservation goals. Mate choice leading to nonrandom mating patterns can exacerbate the loss of genetic diversity in small populations. On theoretical grounds, females should choose high-quality mates. A prediction stemming from chemical communication theory is that competitive males will be better able to saturate an area with scent marks. If this is true, females should mate preferentially with males whose odors they encounter most frequently. We tested this hypothesis with the pygmy loris, Nycticebus pygmaeus, a threatened and poorly studied nocturnal prosimian. For several weeks females were exposed repeatedly to the urine from a particular male, and were then allowed to choose between a male whose odors were familiar and one whose odors were novel. Females showed an unusually strong preference for the familiar-odor male, as indicated by several behavioral measures of mate preference. Conservation managers can use this method as a tool to obtain reproductive pairings that will maximize genetic compatibility and diversity. For example, unsuccessful males may be given the opportunity to reproduce. In captive populations, studbook managers often select pairs in order to optimize outbreeding, but these selected pairings may not coincide with the preferences of the individual animals involved. Although several authors have made theoretical arguments for manipulating mate choice for conservation, this is a novel test of a proximate mechanism that can be manipulated, cultivating applications rather than mere implications.  相似文献   

18.
矿山开采生产主要的环境影响是生态影响,以抚顺新宾榆树铁矿为例,利用影子工程法对矿山开采进行环境经济损失分析,包括生态资源的经济损失和生态系统功能受到影响的经济损失,可用于矿区环境经济损益分析并作为相关建设项目的借鉴。  相似文献   

19.
In many countries, a large proportion of forest biodiversity exists on private land. Legal restrictions are often inadequate to prevent loss of habitat and encourage forest owners to manage areas for biodiversity, especially when these management actions require time, money, and other resources. Environmental programs encouraging these actions through economic incentives can be used instead of additional legal restrictions, although to be efficient and successful, an incentive program must be thoughtfully developed and its conservation goals must be clear. In addition to being economically efficient, programs must be acceptable to landowners and ecologically appropriate, especially with respect to the case-specific objectives and the ecosystems in question. We introduce a sample of voluntary incentive programs for private forests in Europe and North America. We briefly describe the economic, social, and ecological characteristics of the programs and the forests they aim to conserve, and evaluate the success of these programs with respect to their explicitly stated goals and the ecological status of the forests in that country or state. Important factors contributing to program success include an allowance for some economic productivity in enrolled forests, a long period since time of program inception, and little interference from other incentive programs.  相似文献   

20.
To support decision making on complex environmental issues, models are often used to explore the potential impacts of different management alternatives on the environmental system. We explored how different model outcomes affect decision making. Two topics have our particular interest, namely (1) the influence of quantification of qualitative information on decision making, and (2) the influence of reflecting uncertainty in the model outcomes on decision making. We set up a survey, in which we use a case study describing a decision making situation in strategic river management. The survey was disseminated through the Internet. From the results we conclude that the quantification of information in itself does not necessarily change preferences, although the outcomes suggest that preferences converge when based on quantified information. When confronted with uncertainty information, respondents show a preference for the alternative with the smallest chance of negative impacts. The study shows that, whereas the modelling community often strives to provide the policy process with as good, and as detailed information as is possible, their assumption that this will automatically lead to ‘better’ decision making is not self-evident.  相似文献   

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