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1.
Kenneth W. Stolte 《人类与生态风险评估》2001,7(5):1297-1316
The Forest Health Monitoring (FHM) and Forest Inventory and Analyses (FIA) programs are integrated biological monitoring systems that use nationally standardized methods to evaluate and report on the health and sustainability of forest ecosystems in the United States. Many of the anticipated changes in forest ecosystems from climate change were also issues addressed in sections of FHM's National Technical Report 1991 to 1998. The integrated FHM and FIA monitoring systems are currently establishing baseline conditions (status and change) in most States for many of the expected effects, and are projected to have full implementation for all States and Territories in 2003. These monitoring systems utilize a broad suite of indicators of key ecosystem components and processes that are responsive to many biotic and abiotic stressors, including those anticipated from climate change. These programs will contribute essential information for many decades for many of the anticipated changes in forest ecosystem from increasing carbon dioxide concentrations, changing climatic scenarios, and extreme weather events that are probable in the next 30 to 100 years. 相似文献
2.
Nikolaos Zias Alexandra Chroneou Maher K Tabba Anne V Gonzalez Anthony W Gray Carla R Lamb David R Riker John F Beamis Jr 《BMC pulmonary medicine》2008,8(1):1-9
Background
There is increasing evidence that patients with low-risk community acquired pneumonia (CAP) can be effectively treated as outpatients. This study aimed to explore patients' experiences of having pneumonia and seeking health care; their perceptions of the information provided by health professionals; how they self managed at home; their information and support needs; and their beliefs and preferences regarding site of care.Methods
We conducted qualitative, semi-structured interviews with 15 patients who had a confirmed diagnosis of low-risk CAP and had received fewer than 3 days hospital care. Interviews were audio recorded and transcribed, and data were analysed thematically.Results
Most patients left hospital with no clear understanding of pneumonia, its treatment or follow-up and most identified additional-other specific information needs when they got home. Some were unable to independently address their activities of daily living in their first days at home. Main concerns after discharge related to the cause and implications of pneumonia, symptom trajectory and prevention of transmission. Most sought advice from their GP in their first days at home, and indicated they would have appreciated a follow-up phone call or visit to discuss their concerns. Patients' preferences for site of care varied and appeared to be influenced by beliefs about safety (fear of rapid deterioration at home or acquiring an infection in hospital), family burden, access to support, or confidence in home-care services. Those who received intravenous (IV) medication were more likely to state a preference for hospital care.Conclusion
Trends to support community-based treatment of CAP should be accompanied by increased attention to the information and support needs of patients who go home to self-manage. Although some information needs can be anticipated and addressed on diagnosis, specific needs often do not become apparent until patients return home, so some access to information and support in the community is likely to be necessary. Our finding that patients who received IV treatment for low-risk CAP were concerned about the relative safety of home-based care highlights the potential importance of the inferences patients make from treatment modalities, and also the need to ensure that patients' expectations and understandings are managed effectively. 相似文献3.
Telecare is often regarded as a win/win solution to the growing problem of meeting the care needs of an ageing population. In this paper we call attention to some of the ways in which telecare is not a win/win solution but rather aggravates many of the long‐standing ethical tensions that surround the care of the elderly. It may reduce the call on carers' time and energy by automating some aspects of care, particularly daily monitoring. This can release carers for other caring activities. On the other hand, remote and impersonal monitoring seems to fall short of providing care. Monitoring may be used to help elderly users retain independence. But it may also increase the amount of information which flows from users to carers, which can result in a form of function‐creep that actually undermines independence. 相似文献
4.
F. A. Majeed N. Chaturvedi R. Reading Y. Ben-Shlomo 《BMJ (Clinical research ed.)》1994,308(6941):1426-1429
Although need is often assumed to be the most important factor in determining the use of health services, there are many inequities in the provision and use of NHS services in both primary and secondary care. For example, existing data from district child health information services have been combined with census data for small areas to show wide variations in immunisation rates between affluent and deprived areas. Purchasers of health care are already responsible for assessing health needs and evaluating services, and the process of monitoring equity is a logical extension of these activities. Routine data sources used to collect activity data in both primary and secondary care can be used to assess needs for care and monitor how well these needs are met. Purchasers and providers should collaborate to improve the usefulness of these routine data and to develop a framework for monitoring and promoting equity more systematically. 相似文献
5.
Model organisms have proved to be highly informative for many types of genetic studies involving ‘conventional’ genes. The results have often been successfully generalized to other closely related organisms and also, perhaps surprisingly frequently, to more distantly related organisms. Because of the wealth of previous knowledge and their availability and convenience, model organisms were often the species of choice for many of the earlier studies of transposable elements. The question arises whether the results of genetic studies of transposable elements in model organisms can be extrapolated in the same ways as those of conventional genes? A number of observations suggest that special care needs to be taken in generalizing the results from model organisms to other species. A hallmark of many transposable elements is their ability to amplify rapidly in species genomes. Rapid spread of a newly invaded element throughout a species range has also been demonstrated. The types and genomic copy numbers of transposable elements have been shown to differ greatly between some closely related species. Horizontal transfer of transposable elements appears to be more frequent than for nonmobile genes. Furthermore, the population structure of some model organisms has been subject to drastic recent changes that may have some bearing on their transposable element genomic complements. In order to initiate discussion of this question, several case studies of transposable elements in well-studied Drosophila species are presented. 相似文献
6.
M. MacGarvin 《Helgoland Marine Research》1995,49(1-4):647-662
Marine biological monitoring programmes frequently attempt to determine “safe” levels of contamination, based on assumptions
about the assimilative capacity of the environment. This paper argues that such assumptions lack scientific rigour, and do
not form the basis upon which a precautionary policy can be built. It notes the problems associated with assessing toxicological
effects, but centres its attention on the crucial (yet far less discussed) weaknesses in theoretical ecology that make it
extremely unlikely that biological monitoring can determine safe levels of contamination that leave ecosystems unaffected.
It is argued that many marine biologists, if pressed, would concede these shortcomings but believe that, in the face of the
technical difficulties and high costs of pollution prevention, we have no choice but to use such methods. This paper argues,
with examples, that pollution prevention, often with considerable economic savings, is becoming a reality for even the most
problematic substances. The difficulty is that the development of “clean production” methods lie outside the sphere of interest
of those carrying out monitoring, so that measures that attempt to determine safe levels of contamination continue to be advocated.
This gulf needs to be bridged so that the continuation of monitoring programmes that are part of dilute and disperse policies
become regarded as inappropriate, indeed unethical. The paper concludes that this does not mean the end of marine monitoring.
Instead, reliable methods for assessing physical levels of contamination will be required to determine whether the reduction
targets set—as part of the introduction of clean production—are being met. Formidable difficulties will remain, requiring
a precautious approach. Nevertheless, monitoring will no longer carry the burden of attempting to demonstrate that a particular
level of environmental contamination is safe, which is currently destroying its scientific credibility. 相似文献
7.
Sarah F. Brosnan Lucie Salwiczek Redouan Bshary 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2010,365(1553):2699-2710
Cooperation often involves behaviours that reduce immediate payoffs for actors. Delayed benefits have often been argued to pose problems for the evolution of cooperation because learning such contingencies may be difficult as partners may cheat in return. Therefore, the ability to achieve stable cooperation has often been linked to a species'' cognitive abilities, which is in turn linked to the evolution of increasingly complex central nervous systems. However, in their famous 1981 paper, Axelrod and Hamilton stated that in principle even bacteria could play a tit-for-tat strategy in an iterated Prisoner''s Dilemma. While to our knowledge this has not been documented, interspecific mutualisms are present in bacteria, plants and fungi. Moreover, many species which have evolved large brains in complex social environments lack convincing evidence in favour of reciprocity. What conditions must be fulfilled so that organisms with little to no brainpower, including plants and single-celled organisms, can, on average, gain benefits from interactions with partner species? On the other hand, what conditions favour the evolution of large brains and flexible behaviour, which includes the use of misinformation and so on? These questions are critical, as they begin to address why cognitive complexity would emerge when ‘simple’ cooperation is clearly sufficient in some cases. This paper spans the literature from bacteria to humans in our search for the key variables that link cooperation and deception to cognition. 相似文献
8.
《Behavioural processes》1997,39(2):161-176
In isolated pairs of the biparental convict cichlid (Cichlasoma nigrofasciatum) caring for fry, pairbonds can be broken by removal of the fry. Within three hours, the mates of many pairs become so mutually aggressive that the female finally flees from her larger mate, who chases her. The pairbond is mended within seconds upon re-introduction of the fry. Yet removal of young leaves some pairs little or not at all affected. They seem to have more stable pairbonds. Multiple regression of data from 39 pairs on a quantitative measure of pairbond destruction revealed support for the so-called parity-hypothesis, which holds that a cichlid pair is compatible only when the female's aggressiveness compensates for her smaller size. The size of the female relative to the male's, and her aggressiveness relative to his in the undisturbed situation, proved positive predictors of pair stability in the fry stage. Thus the same factors which have earlier been shown to favour pair formation in other biparental cichlids seem also responsible for pair stability in a later stage of the reproductive cycle. 相似文献
9.
Meisel RP 《Evolution》2010,3(4):621-628
Evolution is the unifying principle of all biology, and understanding how evolutionary relationships are represented is critical
for a complete understanding of evolution. Phylogenetic trees are the most conventional tool for displaying evolutionary relationships,
and “tree-thinking” has been coined as a term to describe the ability to conceptualize evolutionary relationships. Students
often lack tree-thinking skills, and developing those skills should be a priority of biology curricula. Many common student
misconceptions have been described, and a successful instructor needs a suite of tools for correcting those misconceptions.
I review the literature on teaching tree-thinking to undergraduate students and suggest how this material can be presented
within an inquiry-based framework. 相似文献
10.
H. B. Wilson M. P. Hassell 《Proceedings. Biological sciences / The Royal Society》1997,264(1385):1189-1195
Host–parasitoid metapopulation models have typically been deterministic models formulated with population numbers as a continuous variable. Spatial heterogeneity in local population abundance is a typical (and often essential) feature of these models and means that, even when average population density is high, some patches have small population sizes. In addition, large temporal population fluctuations are characteristic of many of these models, and this also results in periodically small local population sizes. Whenever population abundances are small, demographic stochasticity can become important in several ways. To investigate this problem, we have reformulated a deterministic, host–parasitoid metapopulation as an integer-based model in which encounters between hosts and parasitoids, and the fecundity of individuals are modelled as stochastic processes. This has a number of important consequences: (1) stochastic fluctuations at small population sizes tend to be amplified by the dynamics to cause massive population variability, i.e. the demographic stochasticity has a destabilizing effect; (2) the spatial patterns of local abundance observed in the deterministic counterpart are largely maintained (although the area of ''spatial chaos'' is extended); (3) at small population sizes, dispersal by discrete individuals leads to a smaller fraction of new patches being colonized, so that parasitoids with small dispersal rates have a greater tendency for extinction and higher dispersal rates have a larger competitive advantage; and (4) competing parasitoids that could coexist in the deterministic model due to spatial segregation cannot now coexist for any combination of parameters. 相似文献
11.
In the present study the quality management system of 39 milling companies was investigated regarding the analysis and the prevention of mycotoxin contamination. 21 companies- mainly companies with a high processing volume - established a quality management system according to DIN EN ISO 9000ff. In view of previous studies the data indicated an improvement of quality management systems in the milling industry during the last years. Nevertheless some powerful instruments of preventive quality management like a supplier assessment have still not been efficiently used in many companies. The monitoring of mycotoxins or the participation in existing monitoring programmes is mainly limited to companies with a high production volume. It is recommended that monitoring programmes should become more attractive for small- and medium-sized companies. Further the development of quality management systems for small and medium-sized companies is required. 相似文献
12.
Jeffrey K. Conner Russell Lande 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2014,369(1649)
Raissa L. Berg had a remarkable career in many respects and an impact on the study of phenotypic integration that continues to increase over 50 years after the publication of her seminal paper in that area. She was born and lived most of her life in Russia, with most of her research focused on measuring spontaneous mutation rates in Drosophila. She was forced to abandon this work during the height of Lysenko''s power in Russia, so she turned temporarily to the study of correlation patterns in plants; ironically, this work has had a more enduring impact than her main body of research. She showed that floral and vegetative traits become decoupled into separate correlation ‘pleiades’ in plants with specialized pollinators, but floral and vegetative traits remain correlated in plants that have less specialized pollination. Unfortunately, her plant work is often mis-cited as providing evidence for increased correlations among floral traits due to selection by pollinators for functional integration, a point she never made and one that is not supported by her data. Still, many studies of correlation pleiades have been conducted in plants, with the results mostly supporting Berg''s hypothesis, although more studies on species with generalized pollination are needed. 相似文献
13.
Today it is generally accepted that there are several endocytic mechanisms, both the clathrin-dependent one and mechanisms which operate without clathrin and with different requirements when it comes to dynamin, small GTP-binding proteins of the Rho family and specific lipids. It should be noted that clathrin-independent endocytosis can occur even when the cholesterol level in the membrane has been reduced to so low levels that caveolae are gone and clathrin-coated membrane areas are flat. Although new investigators in the field take it for granted that there is a multitude of entry mechanisms, it has taken a long time for this to become accepted. However, more work needs to be done, because one can still ask the question: How many endocytic mechanisms does a cell have, what are their function, and how are they regulated? This article describes some of the history of endocytosis research and attempts to give an overview of the complexity of the mechanisms and their regulation. 相似文献
14.
Andrew Clarke 《Invertebrate reproduction & development.》2013,57(2):71-82
The life-history tactics of many Antarctic marine invertebrates suggest that the commonly observed slow rates of growth are adaptations to the pattern of food availability, and not due to low temperature per se. This implies that marine invertebrates have been able, over the course of evolutionary time, to compensate their rates of embryonic development for the effect of temperature. Data from north Atlantic copepods indicate that this is so. It is therefore suggested that the slow rates of embryonic development in many Antarctic marine invertebrates are the result of large egg size, and not the low temperature. Large, slowly developing eggs are part of a suite of tactics, often called K-strategies, which characterise many marine invertebrates in Antarctica. 相似文献
15.
16.
D. Machin 《BMJ (Clinical research ed.)》1997,314(7075):216-219
The media have been full of reports of crisis in the NHS. Although national analyses suggest that the NHS should be able to cope within the increases in spending it has been given, local pressures can leave parts of the service struggling. Firstly, the change to allocation of funds on the basis of population needs has meant that some authorities and trusts have had effective cuts in their budgets, requiring them to trim services. Secondly, the government''s insistence on an annual 3% increase in efficiency may have resulted in authorities taking short term measures that actually decrease efficiency in the long term. Thirdly, health authorities have had to bear the costs of national targets such as reducing waiting lists and junior doctors'' hours as well as local problems such as higher numbers of mentally disordered offenders. However, all these factors can be controlled by national or local management and so their impact is not inevitable. 相似文献
17.
R. J. BERRY 《Biological journal of the Linnean Society. Linnean Society of London》1985,26(4):301-305
The suggestion that speciation involves non-adaptive processes needs further research, not more argument.
Mr Darwin's position might, we think, have been stronger than it is if he had not embarrassed himself with the aphorism, "Natura non facit salturn", which turns up so often in his pages. We believe…that Nature does make jumps now and then and a recognition of the fact is of no small importance in disposing of many minor objections to the doctrine of transmutation (i.e. speciation). 相似文献
Mr Darwin's position might, we think, have been stronger than it is if he had not embarrassed himself with the aphorism, "Natura non facit salturn", which turns up so often in his pages. We believe…that Nature does make jumps now and then and a recognition of the fact is of no small importance in disposing of many minor objections to the doctrine of transmutation (i.e. speciation). 相似文献
18.
Males of many species help in the care and provisioning of offspring, and these investments often correlate with genetic relatedness. For example, many human males invest in the children of sisters, and this is especially so where men are less likely to share genes with children of wives. Although this makes qualitative sense, it has been difficult to support quantitatively. The prevailing model predicts investment in children of sisters only when paternity confidence falls below 0.268. This value is often seen as too low to be credible; so investment in sisters'' children represents an unsolved problem. I show here that the prevailing model rests on a series of restrictive assumptions that underestimate relatedness to sisters'' children. For this reason, it understates the fitness payoff to men who invest in these children. This effect can be substantial, especially in societies with low confidence in paternity. But this effect cannot be estimated solely from confidence in paternity. One must also estimate the probability that two siblings share the same father. 相似文献
19.
In practice the problem of comparing several treatments can often be formulated as which treatment can be considered best. Selection procedures have been designed specifically to answer questions like this one. In many situations selection procedures are more realistic than the usual testing procedures. In this paper an introduction and an overview of selection of populations will be given with special reference to Normal, Binomial, Poisson and Multinomial populations. In the field of agricultural applications these distributions play an important role. Bechhofer's and Gupta's approach are presented side by side for a number of problems. After that the relatively new procedures of Somerville are discussed. Finally, some recent results are presented. 相似文献
20.
Paul D. Meek Guy-Anthony Ballard Peter J. S. Fleming Michael Schaefer Warwick Williams Greg Falzon 《PloS one》2014,9(10)
Camera traps are electrical instruments that emit sounds and light. In recent decades they have become a tool of choice in wildlife research and monitoring. The variability between camera trap models and the methods used are considerable, and little is known about how animals respond to camera trap emissions. It has been reported that some animals show a response to camera traps, and in research this is often undesirable so it is important to understand why the animals are disturbed. We conducted laboratory based investigations to test the audio and infrared optical outputs of 12 camera trap models. Camera traps were measured for audio outputs in an anechoic chamber; we also measured ultrasonic (n = 5) and infrared illumination outputs (n = 7) of a subset of the camera trap models. We then compared the perceptive hearing range (n = 21) and assessed the vision ranges (n = 3) of mammals species (where data existed) to determine if animals can see and hear camera traps. We report that camera traps produce sounds that are well within the perceptive range of most mammals’ hearing and produce illumination that can be seen by many species. 相似文献