首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 0 毫秒
1.
2.
Evidence for long-term cooperative relationships comes from several social birds and mammals. Vampire bats demonstrate cooperative social bonds, and like primates, they maintain these bonds through social grooming. It is unclear, however, to what extent vampires are special among bats in this regard. We compared social grooming rates of common vampire bats Desmodus rotundus and four other group-living bats, Artibeus jamaicensis, Carollia perspicillata, Eidolon helvum and Rousettus aegyptiacus, under the same captive conditions of fixed association and no ectoparasites. We conducted 13 focal sampling sessions for each combination of sex and species, for a total of 1560 presence/absence observations per species. We observed evidence for social grooming in all species, but social grooming rates were on average 14 times higher in vampire bats than in other species. Self-grooming rates did not differ. Vampire bats spent 3.7% of their awake time social grooming (95% CI = 1.5–6.3%), whereas bats of the other species spent 0.1–0.5% of their awake time social grooming. Together with past data, this result supports the hypothesis that the elevated social grooming rate in the vampire bat is an adaptive trait, linked to their social bonding and unique regurgitated food sharing behavior.  相似文献   

3.
In order to promote better practices and communication around end-of-life decision-making, several Canadian hospitals in the province of Quebec have developed a tool called “Levels of Intervention” (LOI). No work to date has been published demonstrating improvement since these forms were implemented. The purpose of the present study was to obtain information about the use of LOI forms across Quebec hospitals and to identify gaps in practice as well as areas for improvement. A retrospective study was undertaken of 299 charts of patients who had died in three Quebec hospitals with a LOI ordered. Results were analysed through a principlism ethical framework. High compliance with the level of intervention ordered at the time of death was recorded, as well as high involvement of patient and/or family, demonstrating the efficiency of LOI in promoting respect for autonomy. Other results show delays in end-of-life care discussions in the course of the hospitalization. Only a small proportion of patients who died had a palliative care consultation, which may reflect equity issues in access to care. This study highlights the importance of the LOI in Quebec and the role it is playing in respect for end-of-life preferences as well as in the involvement of patients and families in the decision-making process. Training specific to end-of-life decision-making conversations would help support the LOI form’s use, as would developing provincial or national guidelines on the use of LOI to standardize organizational policies and practice around end-of-life care.  相似文献   

4.
5.
The increasing interest in the human microbiota raises some interesting questions about the terminology we use to describe some of the structures and strategies employed by commensal and pathogenic microbes to compete in these complex biological ecosystems. For example, all microbes arriving in the alimentary tract face the task of surviving passage through the stomach, coping with bile, interacting with the immune system, competing with the established microbiota, and obtaining sufficient nutrients to gain a foothold in this hostile environment. It is not surprising then that many gastrointestinal microbes (both pathogens and commensals) use similar strategies to overcome the challenges associated with this particular biological niche. Given that many of these structures and strategies were discovered and characterized in pathogens and because they often play important roles in establishing and maintaining an infection, they have often been characterized as virulence factors. It would be misleading to describe the same strategies and structures found in harmless commensals as “virulence factors,” since they represent a sine qua non for life in the gastrointestinal tract. It may be time to reconsider and refer to them as “niche factors,” both in terms of providing scientific accuracy but also in light of the growing interest in using gut microbes as probiotics, where the distinction between virulence factors and niche factors is likely to be very important from a regulatory perspective.  相似文献   

6.
The diversity of the arthropod fauna in apple orchards in Central Otago was recorded from 1994 to 1999 using beating trays, pitfall traps, and sticky traps and the data analysed by the Shannon–Wiener Index. Three different fruit production systems were compared, conventional (CFP), integrated (IFP), and biological (BFP), to determine whether total arthropod diversity and/or the diversity of natural enemies (predators and parasitoids) could be used to measure the sustainability of their pest management practices. The contribution of natural enemies to the diversity indices was also examined to determine if they reflected the key species essential for sustainable pest management. The diversity of natural enemies in beating trays was found to be the measure most sensitive to changes in pest management. The diversity of both the total arthropod fauna and natural enemies was much lower under CFP than under either IFP or BFP, due to the use of broad-spectrum pesticides. This practice made the CFP programme unsustainable and it is no longer used. During the transition from CFP to IFP, the diversity indices rose to become similar to that in the BFP programme by the third season. The introduction of frequent applications of fungicides in BFP, including lime sulphur, appeared to reduce total arthropod and natural enemy diversity. Falls in the diversity indices for natural enemies were shown to reflect reduced numbers, range, and evenness of natural enemies but not necessarily the key species known to be critical for sustainable pest management. It is proposed that a Shannon–Wiener Index for natural enemies in beating trays of 0.2 or less in summer is strongly indicative of unsustainable pest management in Otago apple orchards. On the other hand, indices of 0.3–0.8, as found under IFP and BFP, do not give unequivocal or quantitative indications of the sustainability of pest management. A suite of other measures of sustainability are more useful, notably combining lower pesticide use, reduced pest damage and presence at harvest, the greater roles of key natural enemies, more effective plant resistance to pests and diseases, and higher profitability.  相似文献   

7.
8.
Tropical reefs shelter one quarter to one third of all marine species but one third of the coral species that construct reefs are now at risk of extinction. Because traditional methods for assessing reef diversity are extremely time consuming, taxonomic expertise for many groups is lacking, and marine organisms are thought to be less vulnerable to extinction, most discussions of reef conservation focus on maintenance of ecosystem services rather than biodiversity loss. In this study involving the three major oceans with reef growth, we provide new biodiversity estimates based on quantitative sampling and DNA barcoding. We focus on crustaceans, which are the second most diverse group of marine metazoans. We show exceptionally high numbers of crustacean species associated with coral reefs relative to sampling effort (525 species from a combined, globally distributed sample area of 6.3 m(2)). The high prevalence of rare species (38% encountered only once), the low level of spatial overlap (81% found in only one locality) and the biogeographic patterns of diversity detected (Indo-West Pacific>Central Pacific>Caribbean) are consistent with results from traditional survey methods, making this approach a reliable and efficient method for assessing and monitoring biodiversity. The finding of such large numbers of species in a small total area suggests that coral reef diversity is seriously under-detected using traditional survey methods, and by implication, underestimated.  相似文献   

9.
10.
The presence of foreign organisms in the colonies of social insects could affect energy allocation to growth and reproduction of these hosts. Highly specialized invaders of such long-lived hosts, however, can be selected to be less harmful. After all, it pays for these symbionts to keep their host’s good health thereby prolonging cohabitation in the homeostatic environment of the termite colony. Here, we investigated such a hypothesis, focusing on populational parameters of a termite host sharing its nest with an obligatory termite inquiline. To this end, 19 natural colonies of Constrictotermes cyphergaster (Silvestri, 1901) (Termitidae: Nasutitermitinae) were sampled and the (i) number of individuals, (ii) proportion of soldier/workers in the colonies, and (iii) presence/absence of obligatory inquiline Inquilinitermes microcerus (Silvestri, 1901) (Termitidae: Termitinae) were measured. Results revealed a negative correlation between the number of individuals and the proportion of soldier/workers in the host colonies with the presence of I. microcerus colonies. In search of causal mechanisms for such a correlation, we inspected life history traits of both, inquilines and hosts, hypothesizing that such a result could indicate either (i) a dampening effect of the inquiline upon its host population or (ii) the coincidence of the moment of inquiline infiltration with the natural reduction of C. cyphergaster populational growth at the onset of its reproductive phase.  相似文献   

11.
Epifluorescence microscopy, flow cytometry, and transmission electron microscopy were used to characterize the community of red fluorescing (emission >665 nm when excited with blue light) phototrophic picoplankton (RFPP) in lakes Huron and Michigan. A population of coccoid to ovate eukaryotic cells with a mean size of 1.2 μm dominated the RFPP community in both surface and deep water samples. Abundant prochlorophyte populations were not found in any samples. Comparisons of counts with epifluorescence microscopy and flow cytometry, revealed that RFPP were adequately enumerated with standard epifluorescence microscopy. These RFPP were significant contributors to total phototrophic picoplankton abundance in both lakes Michigan (24%) and Huron (18%), with maximum seasonal abundance during the May-June period (surface mixing layer temperatures, 3-9 °C). During thermal stratification, maximum vertical abundance was found in the metalimnion/hypolimnion at the 1-5% isolumes. RFPP were only minor contributors (1-7%) to total primary production. Growth rates of RFPP measured with dilution and small inocula growth experiments ranged from 0.05-1.0 d−1. Microzooplankton grazing rates on RFPP measured with dilution experiments were similar to estimated growth rates, accounting for 52-280% of growth on any given date.  相似文献   

12.
13.
Organism body size has been demonstrated to be a discriminating element in shaping the response of living beings to environmental factors, thus playing a fundamental role in community structuring. Despite the importance of studies elucidating relations among communities of different size levels in ecosystems, the attempts that have been made in this sense are still very scarce and a reliable approach for these research still has to be defined. We characterized the benthic communities of bacteria, microbial eukaryotes, meiofauna and macrofauna in a coastal environment, encompassing a 10000-fold gradient in body size, testing and discussing a mixed approach of molecular fingerprinting for microbes and morphological observations for meio- and macrofauna. We found no correlation among structures of the different size-level communities: this suggests that community composition at one size-level could have no (or very low) influence on the community composition at other size-levels. Moreover, each community responds in a different way to the environmental parameters and with a degree of sensitivity which seems to increase with organism size. Therefore, our data indicate that the characterization of all the different size levels is clearly a necessity in order to study the dynamics really acting in a system.  相似文献   

14.
Serum albumin is a major plasma protein in mammalian blood. The importance of this protein lies in its roles in both bioregulation and transport phenomena. Serum albumin binds various metal ions and participates in the transport and storage of fatty acids, bilirubin, steroids amino acids, and many other ligands, usually with regions of hydrophobic surface. Although the primary role of serum albumin is to transport various ligand, its versatile binding capacities and high concentration mean that it can assume a number of additional functions. The major goal of this article is to show how intrinsic disorder is encoded in the amino acid sequence of serum albumin, and how intrinsic disorder is related to functions of this important serum protein.  相似文献   

15.
We find no genetic variation at 550bp ofmtDNA control region among 55 Hainan Eld's deerin an island population that has sufferedrecent population contractions. Congenericspecies show high levels of variation at thislocus. We use a simulation approach to test thelikelihood of various bottleneck scenarios, andshow, in the context of what is known about therecent demographic history of this population,that there are credible scenarios for abottleneck driven by hunting pressure in the1960s that could account for the lack ofvariation at this locus.  相似文献   

16.
Patients who have survived malignant melanoma for more than five years may lack the opportunity to talk about their burden. As a consequence their psychosocial care needs remain undetected and available supportive interventions may not be utilised. Therefore, the psychosocial burden of this patient group needs to be assessed using specific screening instruments. The aim of this study was to investigate the psychosocial burden of long-term melanoma survivors, their psychosocial care needs and the determinants of these needs. We wanted to find out if the use of professional support corresponds to the care needs defined by experts. Using the cancer registry of Rhineland-Palatinate, melanoma patients diagnosed at least 5 years before the survey were contacted by physicians. N = 689 former patients completed the Hornheide Questionnaire (short form HQ-S) to identify psychosocial support need (scale cut off ≥ 16 or item-based cut-off score) and the potential psychosocial determinants of these needs. Additionally, they were asked about their utilisation of the professional support system. More than one third (36%) of them was in need for professional psychosocial support. The highest burden scores concerned worry about tumour progression. Younger age (< 50), higher general fatigue, higher symptom burden, lower general health, negative social interactions and unfulfilled information needs were significant predictors of the need for psychosocial intervention. Related to the percentage of survivors identified as ‘in need’, the professional support system was underused. Further studies should investigate whether using the HQ-S to routinely identify burdened melanoma patients could lead to better fulfilment of their intervention needs, ultimately enhancing health-related quality of life.  相似文献   

17.
We tested for the existence of latitudinal gradients in the body sizes of butterflies in North America, Europe, Australia and the Afrotropics. We initially compared body sizes (measured as male forewing length) of all butterflies found in 5° latitudinal bands in each region, and then evaluated the relationship between body size and latitude statistically using the latitudinal midpoint of each species' distribution. Trends were examined for species in all butterfly families together and for each family separately. We found that gradients in body sizes were inconsistent in different geographical regions and butterfly families; in some cases species were larger towards the tropics, in some they were smaller, and in other cases there were no relationships. Most of the gradients, when they existed, reflected between-family effects arising from changes in the relative numbers of species in each family across regions. We conclude that general ecological explanations for geographical trends in butterfly body sizes are inappropriate, and gradients largely reflect historical patterns of speciation within and between taxa in each biogeographical realm. Thus, the robustness of body size gradients found in other insect groups should be confirmed in future studies by including more than one geographical region whenever possible.  相似文献   

18.
Objective: To evaluate the accuracy of mothers’ perceptions of adolescents’ weight status. Research Methods and Procedures: Parent interviews and adolescent surveys (755) were conducted in an ethnically diverse sample from Project EAT (Eating among Teens). Results: Adolescent weight status was accurately assessed by 60% of mothers, underestimated by 35% of mothers, and overestimated by 5% of mothers. In multivariate analyses, mothers of female adolescents were about half as likely to underestimate their adolescent's weight status as mothers of male adolescents. Nonoverweight mothers were about half as likely as overweight mothers to underestimate their adolescent's weight status. Discussion: Most mothers are able to accurately assess their adolescent's weight status; however, adolescent gender and mothers’ weight status are related to accuracy. Mothers were more likely to underestimate their sons’ weights than their daughters’ weights, and overweight mothers were more likely to be inaccurate in their assessments than nonoverweight mothers. Findings suggest that the majority of parents do not need to be told that their children are overweight; instead, messages to parents of overweight teens should focus on how to provide support for healthy weight management.  相似文献   

19.
Adoption is rare in animals and is usually attributed to kin selection. In a 6-year study of eastern grey kangaroos (Macropus giganteus), 11 of 326 juveniles were adopted. We detected eight adoptions by observing behavioural associations and nursing between marked mothers and young and three more by analysing the relatedness of mothers and young using microsatellite DNA. Four adoptions involved reciprocal switches and three were by mothers whose own pouch young were known to subsequently disappear. Adoptive mothers were not closely related to each other or to adoptees but adoptive mothers and young associated as closely as did biological pairs, as measured by half-weight indices. Switch mothers did not associate closely. Maternal age and body condition did not influence the likelihood of adoption but females were more likely to adopt in years with high densities of females with large pouch young. Adoption did not improve juvenile survival. We conclude that adoptions in this wild population were potentially costly and likely caused by misdirected care, suggesting that eastern grey kangaroos may have poorly developed mother-offspring recognition mechanisms.  相似文献   

20.
Probiotics and Antimicrobial Proteins - The outbreak of diseases leading to substantial loss is a major bottleneck in aquaculture. Over the last decades, the concept of using feed probiotics was...  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号