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961.
962.
Norovirus (NoV) is recognized as the most common cause of foodborne outbreaks. In 2014, an outbreak of acute gastroenteritis occurred on a cruise ship in Brazil, and NoV became the suspected etiology. Here we present the molecular identification of the NoV strains and the use of sequence analysis to determine modes of virus transmission. Food (cream cheese, tuna salad, grilled fish, orange mousse, and vegetables soup) and clinical samples were analyzed by ELISA, conventional RT-PCR, qRT-PCR, and sequencing. Genogroup GII NoV was identified by ELISA and conventional RT-PCR in fecal samples from 5 of 12 patients tested (41.7%), and in the orange mousse food sample by conventional RT-PCR and qRT-PCR. Two fecal GII NoV samples and the orange mousse GII NoV sample were successfully genotyped as GII.Pe (ORF 1), revealed 98.0–98.8% identities among them, and shared phylogenetically distinct cluster. Establishing the source of a NoV outbreak can be a challenging task. In this report, the molecular analysis of the partial RdRp NoV gene provided a powerful tool for genotyping (GII.Pe) and tracking of outbreak-related samples. In addition, the same fast and simple extraction methods applied to clinical samples could be successfully used for complex food matrices, and have the potential to be introduced in routine laboratories for screening foods for presence of NoV.  相似文献   
963.
964.
Fever can reduce mortality in infected animals. Yet, despite its fitness-enhancing qualities, fever often varies among animals. We used several approaches to examine this variation in insects. Texas field crickets (Gryllus texensis) exhibited a modest fever (1 °C increase in preferred body temperature, T pref) after injection of prostaglandin, which putatively mediates fever in both vertebrates and invertebrates, but they did not exhibit fever during chronic exposure to heat-killed bacteria. Further, chronic food limitation and mating status did not affect T pref or the expression of behavioural fever, suggesting limited context dependency of fever in G. texensis. Our meta-analysis of behavioural fever studies indicated that behavioural fever occurs in many insects, but it is not ubiquitous. Thus, both empirical and meta-analytical results suggest that the fever response in insects ‘is widespread, although certainly not inevitable’ (Moore 2002). We highlight the need for future work focusing on standardizing an experimental protocol to measure behavioural fever, understanding the specific mechanism(s) underlying fever in insects, and examining whether ecological or physiological costs often outweigh the benefits of fever and can explain the sporadic nature of fever in insects.  相似文献   
965.
Salmon farming is a widespread activity around the world, also known to promote diverse environmental effects on aquatic ecosystems. However, information regarding the impact of salmon farming on bird assemblages is notably scarce. We hypothesize that salmon farming, by providing food subsidies and physical structures to birds, will change their local community structure. To test this hypothesis, we conducted a seasonal monitoring of bird richness, abundance, and composition at paired salmon pen and control plots in two marine and two lake sites in southern Chile, from fall 2002 to summer 2004. Overall, salmon farming had no significant effects on species richness, but bird abundance was significantly and noticeably higher in salmon pens than in controls. Such aggregation was mainly accounted for by the trophic guilds of omnivores, diving piscivores, carrion eaters, and perching piscivores, but not by invertebrate feeders, herbivores, and surface feeders. Species composition was also significantly and persistently different between salmon pens and controls within each lake or marine locality. The patterns described above remained consistent across environment types and seasons indicating that salmon farming is changing the community structure of birds in both lake and marine habitats by promoting functional and aggregation responses, particularly by favoring species with broader niches. Such local patterns may thus anticipate potential threats from the ongoing expansion of the salmon industry to neighboring areas in Chile, resulting in regional changes of bird communities, toward a less diverse one and dominated by opportunistic, common, and generalist species such as gulls, vultures, and cormorants.  相似文献   
966.
Baigger  A.  Perony  N.  Reuter  M.  Leinert  V.  Melber  M.  Grünberger  S.  Fleischmann  D.  Kerth  G. 《Die Naturwissenschaften》2013,100(9):895-898

Several social mammals, including elephants and some primates, whales and bats, live in multilevel societies that form temporary subgroups. Despite these fission–fusion dynamics, group members often maintain long-term bonds. However, it is unclear whether such individual links and the resulting stable social subunits continue to exist after a complete reorganisation of a society, e.g. following a population crash. Here, we employed a weighted network analysis on 7,109 individual roosting records collected over 4 years in a wild Bechstein’s bat colony. We show that, in response to a strong population decline, the colony’s two stable social subunits fused into a non-modular social network. Nevertheless, in the first year after the crash, long-term bonds were still detectable, suggesting that the bats remembered previous individual relationships. Our findings are important for understanding the flexibility of animal societies in the face of dramatic changes and for the conservation of social mammals with declining populations.

  相似文献   
967.
To find if ornamental plants are applicable to the remediation of metal-polluted areas, the tolerance of chrysanthemum plants (Chysanthemum maximum) var. Shasta to different metals under hydroponic conditions was studied. Their responses as influenced by the mycorrhizal fungus Glomus mosseae (Nicol. & Gerd.) Gerdemann & Trappe BEG25 on substrates containing mine residues were also investigated. Our results showed that chrysanthemum is a metal-tolerant plant under hydroponic conditions, plants behaving as Pb-excluders, whereas Cd, Cu and Ni were accumulated in roots. Low accumulation in flowers was observed for Cd and Cu but it was concentration-dependent. Ni and Pb were not translocated to flowers. Shoot biomass was not significantly affected by the different rates of mine residue addition for both mycorrhizal and non-mycorrhizal plants. Mycorrhizal plants accumulated less Pb and Cu in both shoots and roots than non-mycorrhizal plants. Chysanthemum could be a prospective plant for revegetation of tailings and the use of inoculation may decrease plant metal accumulation in polluted soils.  相似文献   
968.
Ligands present in dissolved organic matter (DOM) form complexes with inorganic divalent mercury (Hg^2+) affecting its bioavailability in pelagic food webs. This investigation addresses the influence of a natural gradient of DOM present in Patagonian lakes on the bioaccumulation of Hg^2+ (the prevailing mercury species in the water column of these lakes) by the algae Cryptomonas erosa and the zooplankters Brachionus calyciflorus and Boeckella antiqua. Hg^2+ accumulation was studied through laboratory experiments using natural water of four oligotrophic Patagonian lakes amended with^197Hg^2+. The bioavailability of Hg^2+ was affected by the concentration and character of DOM. The entrance of Hg^2+ into pelagic food webs occurs mostly through passive and active accumulation. The incorporation of Hg^2+ by Cryptomonas, up to 27% of the Hg^2+ amended, was found to be rapid and dominated by passive adsorption, and was greatest when low molecular weight compounds with protein-like or small phenolic signatures prevailed in the DOM. Conversely, high molecular weight compounds with a humic or fulvic signature kept Hg^2+ in the dissolved phase, resulting in the lowest Hg^2+ accumulation in this algae. In Brachionus and Boeckella the direct incorporation of Hg from the aqueous phase was up to 3% of the Hg^2+ amended. The dietary incorporation of Hg^2+ by Boeckella exceeded the direct absorption of this metal in natural water, and was remarkably similar to the Hg^2+ adsorbed in their prey. Overall, DOM concentration and character affected the adsorption of Hg^2+ by algae through competitive binding, while the incorporation of Hg^2+ into the zooplankton was dominated by trophic or dietary transfer.  相似文献   
969.
We reviewed existing and planned adaptation activities of federal, tribal, state, and local governments and the private sector in the United States (U.S.) to understand what types of adaptation activities are underway across different sectors and scales throughout the country. Primary sources of review included material officially submitted for consideration in the upcoming 2013 U.S. National Climate Assessment and supplemental peer-reviewed and grey literature. Although substantial adaptation planning is occurring in various sectors, levels of government, and the private sector, few measures have been implemented and even fewer have been evaluated. Most adaptation actions to date appear to be incremental changes, not the transformational changes that may be needed in certain cases to adapt to significant changes in climate. While there appear to be no one-size-fits-all adaptations, there are similarities in approaches across scales and sectors, including mainstreaming climate considerations into existing policies and plans, and pursuing no- and low-regrets strategies. Despite the positive momentum in recent years, barriers to implementation still impede action in all sectors and across scales. The most significant barriers include lack of funding, policy and institutional constraints, and difficulty in anticipating climate change given the current state of information on change. However, the practice of adaptation can advance through learning by doing, stakeholder engagements (including “listening sessions”), and sharing of best practices. Efforts to advance adaptation across the U.S. and globally will necessitate the reduction or elimination of barriers, the enhancement of information and best practice sharing mechanisms, and the creation of comprehensive adaptation evaluation metrics.  相似文献   
970.
This work demonstrates the feasibility of meso-scale (100 μm to mm) punching of multiple holes of intricate shapes in metals. Analytical modeling, finite element (FE) simulation, and experimentation are used in this work. Two-dimensional FE simulations in ABAQUS were done with an assumed material modeling and plane-strain condition. A known analytical model was used and compared with the ABAQUS simulation results to understand the effects of clearance between the punch and the die. FE simulation in ABAQUS was done for different clearances and corner radii of the punch, die, and holder. To complement modeling with real experiments and for the purpose of comparison, a set of punches and dies were made to punch out a miniature spring-steel gripper. Comparison of compliant grippers made by wire-cut electro discharge machining (EDM) and punching shows that realizing sharp interior and re-entrant corners by punching is not easy to achieve. However, the promise of realizing meso-scale parts with complicated shapes through punching is demonstrated in this work; and further work is identified and some strategies are suggested for improvement. The main contribution of this paper is in adapting the well-established punching and blanking operations to the meso-scale as a viable alternative to making miniature devices currently dominated by lithography-based techniques.  相似文献   
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