共查询到20条相似文献,搜索用时 31 毫秒
1.
Nest predation is a widespread demographic and evolutionary force in avian reproduction, but few studies have considered the circumstances under which birds might invest in the construction of safe nests. We examined this question using a stochastic simulation model based on a basic passerine breeding season. Nest safety functions were used to translate time invested in nest building into an increase in daily nest survival; that increase could be rapid, requiring only a few days to achieve a safe nest, or slow, taking many days to do so. The maximum achievable safety differed across nest safety functions. Given a limited length to the breeding season, a greater time investment in nest safety detracts from the time available for re‐nesting following successful or unsuccessful nesting attempts. In many circumstances, the best option is a quick‐build ‘minimal’ nest that provides adequate support for young, but little additional safety from attacks. This is especially true for scenarios that allow for multiple nesting attempts across a season. However, relatively safe nests that can be built fairly quickly are uniformly favored options. Safe, long‐build nests are favored only when they provide a great deal of safety over other nest‐building options, but greater safety alone is not sufficient for such investment. Simulations allowing only a single nesting attempt generally favor a greater investment in nest safety. Parental survival is another important factor in nest investment. Increased danger to the parent during nest building strongly favors a low investment in nests. However, substantial investment in a safe nest is favored when that safety extends to the incubating parent. Our results provide some insight into the prevalence of seemingly unsafe, open‐cup nests across the bird world, but the range of nest types that could potentially be built by a given species is an open question. 相似文献
2.
The statistical test of the conventional hypothesis of "no treatment effect" is commonly used in the evaluation of mutagenicity experiments. Failing to reject the hypothesis often leads to the conclusion in favour of safety. The major drawback of this indirect approach is that what is controlled by a prespecified level alpha is the probability of erroneously concluding hazard (producer risk). However, the primary concern of safety assessment is the control of the consumer risk, i.e. limiting the probability of erroneously concluding that a product is safe. In order to restrict this risk, safety has to be formulated as the alternative, and hazard, i.e. the opposite, has to be formulated as the hypothesis. The direct safety approach is examined for the case when the corresponding threshold value is expressed either as a fraction of the population mean for the negative control, or as a fraction of the difference between the positive and negative controls. 相似文献
3.
Jukka Rautonen 《Biologicals》2010,38(1):97-99
The relationship between free trade, self-sufficiency and safety of blood and blood components has been a perennial discussion topic in the blood service community. Traditionally, national self-sufficiency has been perceived as the ultimate goal that would also maximize safety. However, very few countries are, or can be, truly self-sufficient when self-sufficiency is understood correctly to encompass the whole value chain from the blood donor to the finished product. This is most striking when plasma derived medicines are considered. Free trade of blood products, or competition, as such can have a negative or positive effect on blood safety. Further, free trade of equipment and reagents and several plasma medicines is actually necessary to meet the domestic demand for blood and blood derivatives in most countries. Opposing free trade due to dogmatic reasons is not in the best interest of any country and will be especially harmful for the developing world. Competition between blood services in the USA has been present for decades. The more than threefold differences in blood product prices between European blood services indicate that competition is long overdue in Europe, too. This competition should be welcomed but carefully and proactively regulated to avoid putting safe and secure blood supply at risk. 相似文献
4.
The traditional “safety factor”; method has been used for years to establish occupational exposure limits (OELs) for active ingredients used in drugs. In the past, a single safety factor was used to address all sources of uncertainty in the limit setting process. The traditional 100‐fold safety factor commonly used to derive an acceptable daily intake value incorporates a default factor of 10 each to account for interindividual variability and interspecies extrapolation. Use of these defaults can lead to overly conservative health‐based limits, especially when they are combined with other (up to 10‐fold) factors to adjust for inadequacies in the available database. In recent years, attempts have been made to quantitate individual sources of uncertainty and variability to improve the scientific basis for OELs. In this paper we discuss the science supporting reductions in the traditional default uncertainty factors. A number of workplace‐specific factors also support reductions in these factors. Recently proposed alternative methodologies provide a framework to make maximum use of preclinical and clinical information, e.g., toxicokinetic and toxicodynamic data, to reduce uncertainties when establishing OELs for pharmaceutical active ingredients. 相似文献
5.
Refrigerated processed foods of extended durability rely on a mild heat treatment combined with refrigerated storage to ensure microbiological safety and quality. The principal microbiological safety risk in foods of this type is non-proteolytic Clostridium botulinum. In this article the combined effect of mild heat treatment and refrigerated storage on the time to growth and probability of growth from spores of non-proteolytic Cl. botulinum is described. Spores of non-proteolytic Cl. botulinum (two strains each of type B, E and F) were heated at 90°C for between 0 and 60 min and subsequently incubated at 5°, 10° or 30°C in PYGS broth in the presence or absence of lysozyme. The number of spores that resulted in turbidity depended on the combination of heat treatment, incubation time and incubation temperature they received. Heating at 90°C for 1 or more min ensured a 106 reduction when spores were subsequently incubated at 5°C for up to 23 weeks. Heating at 90°C for 60 min ensured a 106 reduction over 23 weeks when subsequent incubation was at 10°C in the presence of added lysozyme. The same treatment did not reduce the spore population by 106 when subsequent incubation was at 30°C. 相似文献
6.
7.
Gavin Daker-White Rebecca Hays Jennifer McSharry Sally Giles Sudeh Cheraghi-Sohi Penny Rhodes Caroline Sanders 《PloS one》2015,10(8)
Objective
Studies of patient safety in health care have traditionally focused on hospital medicine. However, recent years have seen more research located in primary care settings which have different features compared to secondary care. This study set out to synthesize published qualitative research concerning patient safety in primary care in order to build a conceptual model.Method
Meta-ethnography, an interpretive synthesis method whereby third order interpretations are produced that best describe the groups of findings contained in the reports of primary studies.Results
Forty-eight studies were included as 5 discrete subsets where the findings were translated into one another: patients’ perspectives of safety, staff perspectives of safety, medication safety, systems or organisational issues and the primary/secondary care interface. The studies were focused predominantly on issues seen to either improve or compromise patient safety. These issues related to the characteristics or behaviour of patients, staff or clinical systems and interactions between staff, patients and staff, or people and systems. Electronic health records, protocols and guidelines could be seen to both degrade and improve patient safety in different circumstances. A conceptual reading of the studies pointed to patient safety as a subjective feeling or judgement grounded in moral views and with potentially hidden psychological consequences affecting care processes and relationships. The main threats to safety appeared to derive from ‘grand’ systems issues, for example involving service accessibility, resources or working hours which may not be amenable to effective intervention by individual practices or health workers, especially in the context of a public health system.Conclusion
Overall, the findings underline the human elements in patient safety primary health care. The key to patient safety lies in effective face-to-face communication between patients and health care staff or between the different staff involved in the care of an individual patient. Electronic systems can compromise safety when they override the opportunities for face-to-face communication. The circumstances under which guidelines or protocols are seen to either compromise or improve patient safety needs further investigation. 相似文献8.
Daisuke Ikeno Kazuhiko Kimachi Yoichiro Kino Seiichi Harada Kayo Yoshida Shinji Tochihara Shigeyuki Itamura Takato Odagiri Masato Tashiro Kenji Okada Chiaki Miyazaki Kohji Ueda 《Microbiology and immunology》2010,54(2):81-88
The immunogenicity and safety profile of an inactivated whole‐virion influenza A (H5N1, NIBRG‐14) vaccine with alum adjuvant that was administered by IM or SC injection in a phase I clinical study involving 120 healthy Japanese men aged 20–40 years is described. The serological response of the IM group was stronger than that of the SC group. Local adverse events were less severe with IM injection than with SC injection, while similar systemic adverse events were seen in both groups. These results indicate that, when administering an inactivated whole virion vaccine with alum adjuvant for pandemic influenza, IM injection may achieve better immunogenicity and safety than SC injection. 相似文献
9.
The ability to identify, develop, and exploit conditions of safety and security is central to survival and mental health, but little is known of the neurobiology of these processes or associated positive modulations of affective state. We studied electrophysiological and affective correlates of learned safety by negatively correlating an auditory conditioned stimulus (CS) with aversive events (US). This CS came to signify a period of protection, reducing fear responses to predictors of the US and increasing adventurous exploration of a novel environment. In nonaversive conditions, mice turn on the CS when given the opportunity. Thus, conditioned safety involves a reduction of learned and instinctive fear, as well as positive affective responses. Concurrent electrophysiological measurements identified a safety learning-induced long-lasting depression of CS-evoked activity in the lateral nucleus of the amygdala, consistent with fear reduction, and an increase of CS-evoked activity in a region of the striatum involved in positive affect, euphoric responses, and reward. 相似文献
10.
P. J. Heidt 《Antonie van Leeuwenhoek》1982,48(4):373-381
A modified microbiological safety cabinet which can be used as a class II and a class III safety cabinet has been bacteriologically tested. This cabinet makes use of a high-speed down-flow air curtain in the front opening to minimize the amount of air escaping over the arms of the operator. By using artificial aerosols and a dummy or a test person placing his arms into the working opening of the cabinet, a transfer from the inside to the environment was detected only when the highest concentration of the test aerosol was used. Since the number of bacteria detected was very low, this is considered to be acceptable. when the cabinet was used as a class III type, with a glove panel mounted in the front opening, leakage from the environment occurred. This could be completely prevented by fixing tape over the hinge of the front panel.The conclusion is drawn that this type of biohazard hood can be safely used as a class II and a class III microbiological safety cabinet, provided the construction of the hinge of the front panel will be adapted to prevent transfer from the environment to the working area. 相似文献
11.
During storage of moist animal feed, growth of detrimental fungi causing spoilage, or being mycotoxigenic or pathogenic, is
a severe problem. Addition of biopreservative yeasts or lactic acid bacteria can significantly reduce this problem. However,
their use requires several careful considerations. One is the safety to the animal, humans and the environment, tightly connected
to legal aspects and the need for pre-market authorisation when supplementing feed with microorganisms. Although both yeasts
and lactic acid bacteria are considered comparatively safe organisms due to low production of toxic metabolites, it is of
great importance to understand the mechanisms behind the biopreservative abilities. Another important issue concerns practical
aspects, such as the economic production of large amounts of the organisms and the development of a suitable formulation giving
the organisms a long shelf life. These aspects are discussed and a recommendation of this review is that both safety and formulation
aspects of a specific microbe should be considered at an early stage in the selection of new organisms with biopreservation
potential. 相似文献
12.
This article considers global tests of differences between paired vectors of binomial probabilities, based on data from two dependent multivariate binary samples. Difference is defined as either an inhomogeneity in the marginal distributions or asymmetry in the joint distribution. For detecting the first type of difference, we propose a multivariate extension of McNemar's test and show that it is a generalized score test under a generalized estimating equations (GEE) approach. Univariate features such as the relationship between the Wald and score tests and the dropout of pairs with the same response carry over to the multivariate case and the test does not depend on the working correlation assumption among the components of the multivariate response. For sparse or imbalanced data, such as occurs when the number of variables is large or the proportions are close to zero, the test is best implemented using a bootstrap, and if this is computationally too complex, a permutation distribution. We apply the test to safety data for a drug, in which two doses are evaluated by comparing multiple responses by the same subjects to each one of them. 相似文献
13.
区域粮食安全的动态研究--以延安市宝塔区为例 总被引:8,自引:1,他引:8
粮食安全的研究对地区的发展是极为重要的因素,20世纪70年代以后,国内外对粮食安全的研究相继展开,不同领域的专家从不同角度对粮食安全问题进行研究,同时还有一些地区的实例研究。本文从粮食的数量、质量和持续发展三个方面分别对粮食安全进行分析,并以位于黄土高原丘陵沟壑区的延安市宝塔区为例进行实例研究,结果表明,延安市宝塔区的粮食并不能完全满足小康水平的400kg.人-1,尤其是随着耕地面积的流失和饲粮性动物的饲养的增加,粮食数量安全显得更为重要;在粮食质量方面,相对于延安地区和陕西省而言,该地区的粮食质量在有害物质方面还比较安全;由于处于城郊区,宝塔区的耕地处于较大的压力下,需要改善土地利用结构、提高科技生产水平或者从外地调入粮食以满足其发展的需要。 相似文献
14.
15.
Matthew J. McNulty Yuri Gleba Daniel Tusé Simone Hahn-Löbmann Anatoli Giritch Somen Nandi Karen A. McDonald 《Biotechnology progress》2020,36(1):e2896
Continuous reports of foodborne illnesses worldwide and the prevalence of antibiotic-resistant bacteria mandate novel interventions to assure the safety of our food. Treatment of a variety of foods with bacteriophage-derived lysins and bacteriocin-class antimicrobial proteins has been shown to protect against high-risk pathogens at multiple intervention points along the food supply chain. The most significant barrier to the adoption of antimicrobial proteins as a food safety intervention by the food industry is the high production cost using current fermentation-based approaches. Recently, plants have been shown to produce antimicrobial proteins with accumulation as high as 3 g/kg fresh weight and with demonstrated activity against major foodborne pathogens. To investigate potential economic advantages and scalability of this novel platform, we evaluated a highly efficient transgenic plant-based production process. A detailed process simulation model was developed to help identify economic “hot spots” for research and development focus including process operating parameters, unit operations, consumables, and/or raw materials that have the most significant impact on production costs. Our analyses indicate that the unit production cost of antimicrobial proteins in plants at commercial scale for three scenarios is $3.00–6.88/g, which can support a competitive selling price to traditional food safety treatments. 相似文献
16.
17.
Thomann WR 《ILAR journal / National Research Council, Institute of Laboratory Animal Resources》2003,44(1):13-19
Chemical safety is an essential element of an effective occupational health and safety program. Controlling exposures to chemical agents requires a careful process of hazard recognition, risk assessment, development of control measures, communication of the risks and control measures, and training to ensure that the indicated controls will be utilized. Managing chemical safety in animal care and use presents a unique challenge, in part because research is frequently conducted in two very different environments--the research laboratory and the animal care facility. The chemical agents specific to each of these environments are typically well understood by the employees working there; however, the extent of understanding may not be adequate when these individuals, or chemicals, cross over into the other environment. In addition, many chemicals utilized in animal research are not typically used in the research laboratory, and therefore the level of employee knowledge and proficiency may be less compared with more routinely used materials. Finally, the research protocol may involve the exposure of laboratory animals to either toxic chemicals or chemicals with unknown hazards. Such animal protocols require careful review to minimize the potential for unanticipated exposures of the research staff or animal care personnel. Numerous guidelines and regulations are cited, which define the standard of practice for the safe use of chemicals. Key chemical safety issues relevant to personnel involved in the care and use of research animals are discussed. 相似文献
18.
H2-receptor antagonists have been widely prescribed in the last 20 years and are considered to rank among the safest drugs known. In several countries they have been switched to over-the-counter (OTC) status, and a similar move is under consideration in Canada. Some concerns have been raised as to the effectiveness of these drugs in the treatment of dyspepsia and heartburn, their safety when taken for self-diagnosed symptoms, and the potential for their use to delay diagnosis or mask serious disease. The author presents evidence to support the use of OTC H2-receptor antagonists in the treatment of dyspepsia. He argues that the safety record of these drugs is reassuring and that they are unlikely to mask gastric cancer. Finally, he describes the appropriate place of OTC H2-receptor antagonists in the overall management of acid-related disorders. 相似文献
19.
Image-guided percutaneous treatments for echinococcal cysts were introduced in the mid-eighties. Today they represent a third therapeutic option, after surgery and benzimidazole derivatives. Two types of percutaneous treatments are available, based on the destruction of the germinal layer or the evacuation of the endocyst. To assess the extent of their use and their safety, a Medline search of the literature on this subject was performed. The number of cysts treated, their anatomical sites, the complications and, length of follow-up (when available), were all examined. The results show that percutaneous treatments for cystic echinococcosis are safe and efficacious in selected anatomical sites, provided basic safety issues are correctly addressed. However, before drawing final conclusions, a more detailed analysis of the literature is needed. Percutaneous treatments could be simplified and made more effective if a scolecidal agent could be found that melts the entire endocyst without causing harm to the biliary epithelium. 相似文献
20.
A technical safety analysis has been performed on a containment-level-2 pilot plant in order to assess an upgrading of the
existing facility, which should comply with good manufacturing practices. The results were obtained by employing the hazard
and operability (HAZOP) assessment method and are discussed in the light of the appropriateness of this procedural tool for
low-hazard biotechnology applications. The potential release of micro-organisms accounts only for a minor part of the hazardous
consequences. However, in certain cases the release of a large or moderate amount of micro-organisms would not be immediately
identified. Most of the actions required to avoid these consequences fall into the realm of operational procedures. As a major
part of potential failures result from human errors, standard operating procedures play a prominent role when establishing
the concept of safety management. The HAZOP assessment method was found to be adequate for the type of process under investigation.
The results also may be used for the generation of checklists which, in most cases, are sufficient for routine safety assurance.
Received: 2 September 1997 / Received revision: 12 February 1998 / Accepted: 6 March 1998 相似文献