188 research outputs found

    The cephalopod prey of the Weddell seal, Leptonychotes weddellii, a biological sampler of the Antarctic marine ecosystem

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    Weddell seals, Leptonychotes weddellii, are important apex predators in the food web of the Antarctic marine ecosystem. However, detailed information on their trophic relationships with cephalopods is scarce. Moreover, cephalopods play a key role in the marine environment, but knowledge of their feeding habits is limited by lack of data. Here, we have combined the use of this seal as a biological sampler together with measurements of the stable isotopic signature of the beaks of their cephalopod prey. Thus, the aims of the present study were: (1) to examine in detail the cephalopod portion of the diet of Weddell seals by means of scat analysis and (2) to assess the habitat use and trophic level of the different cephalopod prey taxa identified. From January to February 2009, a total of 48 faecal droppings were collected at Hope Bay, Antarctic Peninsula. Cephalopods were mainly represented by beaks (n = 83) which were identified to the lowest possible taxonomic level. Furthermore, subsamples of beaks were separated for further isotopic analysis. Relative abundance of stable isotopes of carbon (δ13C) and nitrogen (δ15N) was determined by continuous-flow isotope-ratio mass spectrometry. Cephalopods were represented uniquely by octopods of the subfamily Eledoninae. Pareledone turqueti was the dominant prey species followed by the papillated Pareledone species group and Adelieledone polymorpha. We conclude that Weddell seals preyed primarily on benthic prey resources. Furthermore, the relatively similar δ13C and δ15N values in beaks of the three octopod prey taxa suggest that these share the same type of habitat and occupy similar trophic level positions

    Discovery of new colonies by Sentinel2 reveals good and bad news for emperor

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    The distribution of emperor penguins is circumpolar, with 54 colony locations currently reported of which 50 are currently extant as of 2019. Here we report on eight newly discovered colonies and confirm the rediscovery of three breeding sites, only previously reported in the era before Very High Resolution satellite imagery was available, making a total of 61 breeding locations. This represents an increase of ~20% in the number of breeding sites, but, as most of the colonies appear to be small, they may only increase the total population by around 5–10%. The discoveries have been facilitated by the use of Sentinel2 satellite imagery, which has a higher resolution and more efficient search mechanism than the Landsat data previously used to search for colonies. The small size of these new colonies indicates that considerations of reproductive output in relation to metabolic rate during huddling is likely to be of interest. Some of the colonies exist in offshore habitats, something not previously reported for emperor penguins. Comparison with recent modelling results show that the geographic locations of all the newly found colonies are in areas likely to be highly vulnerable under business‐as‐usual greenhouse gas emissions scenarios, suggesting that population decreases for the species will be greater than previously thought

    Adoption incentives and environmental policy timing under asymmetric information and strategic firm behaviour

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    We consider the incentives of a single firm to invest in a cleaner technology under emission quotas and emission taxation. We assume asymmetric information about the firm's cost of employing the new technology. Policy is set either before the firm invests (commitment) or after (time consistency). Contrary to conventional wisdom, we find that with commitment (time consistency), quotas give higher (lower) investment incentives than taxes. With quotas (taxes), commitment generally leads to higher (lower) welfare than time consistency. Under commitment with quadratic abatement costs and environmental damages, a modified Weitzman rule applies and quotas usually lead to higher welfare than taxes

    Proposing to use artificial neural Networks for NoSQL attack detection

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    [EN] Relationships databases have enjoyed a certain boom in software worlds until now. These days, with the rise of modern applications, unstructured data production, traditional databases do not completely meet the needs of all systems. Regarding these issues, NOSQL databases have been developed and are a good alternative. But security aspects stay behind. Injection attacks are the most serious class of web attacks that are not taken seriously in NoSQL. This paper presents a Neural Network model approach for NoSQL injection. This method attempts to use the best and most effective features to identify an injection. The features used are divided into two categories, the first one based on the content of the request, and the second one independent of the request meta parameters. In order to detect attack payloads features, we work on character level analysis to obtain malicious rate of user inputs. The results demonstrate that our model has detected more attack payloads compare with models that work black list approach in keyword level

    Evidence for Avian Intrathoracic Air Sacs in a New Predatory Dinosaur from Argentina

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    Background: Living birds possess a unique heterogeneous pulmonary system composed of a rigid, dorsally-anchored lung and several compliant air sacs that operate as bellows, driving inspired air through the lung. Evidence from the fossil record for the origin and evolution of this system is extremely limited, because lungs do not fossilize and because the bellow-like air sacs in living birds only rarely penetrate (pneumatize) skeletal bone and thus leave a record of their presence. Methodology/Principal Findings: We describe a new predatory dinosaur from Upper Cretaceous rocks in Argentina, Aerosteon riocoloradensis gen. et sp. nov., that exhibits extreme pneumatization of skeletal bone, including pneumatic hollowing of the furcula and ilium. In living birds, these two bones are pneumatized by diverticulae of air sacs (clavicular, abdominal) that are involved in pulmonary ventilation. We also describe several pneumatized gastralia (‘‘stomach ribs’’), which suggest that diverticulae of the air sac system were present in surface tissues of the thorax. Conclusions/Significance: We present a four-phase model for the evolution of avian air sacs and costosternal-driven lung ventilation based on the known fossil record of theropod dinosaurs and osteological correlates in extant birds: (1) Phase I—Elaboration of paraxial cervical air sacs in basal theropods no later than the earliest Late Triassic. (2) Phase II—Differentiation of avian ventilatory air sacs, including both cranial (clavicular air sac) and caudal (abdominal air sac) divisions, in basal tetanurans during the Jurassic. A heterogeneous respiratory tract wit

    BVDV and BHV-1 Infections in Dairy Herds in Northern and Northeastern Thailand

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    Bulk milk samples from 220 dairy herds were collected at 9 public milk collection centres in the northeastern and northern Thailand, and a subset of 11 herds was selected for individual testing. The samples were tested for presence of antibodies to BVDV and BHV-1 using an indirect ELISA. The results from the bulk milk testing demonstrated a moderate level of exposure to BVDV and BHV-1 (73% and 67%, respectively). However, the low proportion of herds with high BVDV antibody-levels (13%) and the low within-herd seroprevalence of BVDV and BHV-1 in the 11 herds (24% and 5%, respectively), particularly among the young stock (15% and 0%, respectively), demonstrated a low prevalence of active BVDV infection and a low rate of reactivation of latent BHV-1. The presence of a self-clearance process was also indicated by the results from the individual testing. Moreover, a surprisingly low prevalence of BVDV and BHV-1 antibody-positive herds at one of the milk centres was found. This centre was established 5–10 years before the others. Our impression is that this reflects the self-clearance process, where consecutive replacement of imported infected animals without further spread has resulted in a nearly total elimination of the infections. Based on our experiences and on these results we are convinced that this process can continue if there is awareness of herd biosecurity. This is especially important in the context of a future intensification of the dairy production

    Drivers and Socioeconomic Impacts of Tourism Participation in Protected Areas

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    Nature-based tourism has the potential to enhance global biodiversity conservation by providing alternative livelihood strategies for local people, which may alleviate poverty in and around protected areas. Despite the popularity of the concept of nature-based tourism as an integrated conservation and development tool, empirical research on its actual socioeconomic benefits, on the distributional pattern of these benefits, and on its direct driving factors is lacking, because relevant long-term data are rarely available. In a multi-year study in Wolong Nature Reserve, China, we followed a representative sample of 220 local households from 1999 to 2007 to investigate the diverse benefits that these households received from recent development of nature-based tourism in the area. Within eight years, the number of households directly participating in tourism activities increased from nine to sixty. In addition, about two-thirds of the other households received indirect financial benefits from tourism. We constructed an empirical household economic model to identify the factors that led to household-level participation in tourism. The results reveal the effects of local households' livelihood assets (i.e., financial, human, natural, physical, and social capitals) on the likelihood to participate directly in tourism. In general, households with greater financial (e.g., income), physical (e.g., access to key tourism sites), human (e.g., education), and social (e.g., kinship with local government officials) capitals and less natural capital (e.g., cropland) were more likely to participate in tourism activities. We found that residents in households participating in tourism tended to perceive more non-financial benefits in addition to more negative environmental impacts of tourism compared with households not participating in tourism. These findings suggest that socioeconomic impact analysis and change monitoring should be included in nature-based tourism management systems for long-term sustainability of protected areas

    Anion-Sensitive Regions of L-Type CaV1.2 Calcium Channels Expressed in HEK293 Cells

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    L-type calcium currents (ICa) are influenced by changes in extracellular chloride, but sites of anion effects have not been identified. Our experiments showed that CaV1.2 currents expressed in HEK293 cells are strongly inhibited by replacing extracellular chloride with gluconate or perchlorate. Variance-mean analysis of ICa and cell-attached patch single channel recordings indicate that gluconate-induced inhibition is due to intracellular anion effects on Ca2+ channel open probability, not conductance. Inhibition of CaV1.2 currents produced by replacing chloride with gluconate was reduced from ∼75%–80% to ∼50% by omitting β subunits but unaffected by omitting α2δ subunits. Similarly, gluconate inhibition was reduced to ∼50% by deleting an α1 subunit N-terminal region of 15 residues critical for β subunit interactions regulating open probability. Omitting β subunits with this mutant α1 subunit did not further diminish inhibition. Gluconate inhibition was unchanged with expression of different β subunits. Truncating the C terminus at AA1665 reduced gluconate inhibition from ∼75%–80% to ∼50% whereas truncating it at AA1700 had no effect. Neutralizing arginines at AA1696 and 1697 by replacement with glutamines reduced gluconate inhibition to ∼60% indicating these residues are particularly important for anion effects. Expressing CaV1.2 channels that lacked both N and C termini reduced gluconate inhibition to ∼25% consistent with additive interactions between the two tail regions. Our results suggest that modest changes in intracellular anion concentration can produce significant effects on CaV1.2 currents mediated by changes in channel open probability involving β subunit interactions with the N terminus and a short C terminal region

    The Siblings With Ischemic Stroke Study (SWISS) Protocol

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    BACKGROUND: Family history and twins studies suggest an inherited component to ischemic stroke risk. Candidate gene association studies have been performed but have limited capacity to identify novel risk factor genes. The Siblings With Ischemic Stroke Study (SWISS) aims to conduct a genome-wide scan in sibling pairs concordant or discordant for ischemic stroke to identify novel genetic risk factors through linkage analysis. METHODS: Screening at multiple clinical centers identifies patients (probands) with radiographically confirmed ischemic stroke and a family history of at least 1 living full sibling with stroke. After giving informed consent, without violating privacy among other family members, the proband invites siblings concordant and discordant for stroke to participate. Siblings then contact the study coordinating center. The diagnosis of ischemic stroke in potentially concordant siblings is confirmed by systematic centralized review of medical records. The stroke-free status of potentially discordant siblings is confirmed by validated structured telephone interview. Blood samples for DNA analysis are taken from concordant sibling pairs and, if applicable, from 1 discordant sibling. Epstein-Barr virus-transformed lymphoblastoid cell lines are created, and a scan of the human genome is planned. DISCUSSION: Conducting adequately powered genomics studies of stroke in humans is challenging because of the heterogeneity of the stroke phenotype and the difficulty of obtaining DNA samples from clinically well-characterized members of a cohort of stroke pedigrees. The multicentered design of this study is intended to efficiently assemble a cohort of ischemic stroke pedigrees without invoking community consent or using cold-calling of pedigree members

    The use of antenatal and postnatal care: perspectives and experiences of women and health care providers in rural southern Tanzania

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    BACKGROUND\ud \ud Although antenatal care coverage in Tanzania is high, worrying gaps exist in terms of its quality and ability to prevent, diagnose or treat complications. Moreover, much less is known about the utilisation of postnatal care, by which we mean the care of mother and baby that begins one hour after the delivery until six weeks after childbirth. We describe the perspectives and experiences of women and health care providers on the use of antenatal and postnatal services.\ud \ud METHODS\ud \ud From March 2007 to January 2008, we conducted in-depth interviews with health care providers and village based informants in 8 villages of Lindi Rural and Tandahimba districts in southern Tanzania. Eight focus group discussions were also conducted with women who had babies younger than one year and pregnant women. The discussion guide included information about timing of antenatal and postnatal services, perceptions of the rationale and importance of antenatal and postnatal care, barriers to utilisation and suggestions for improvement.\ud \ud RESULTS\ud \ud Women were generally positive about both antenatal and postnatal care. Among common reasons mentioned for late initiation of antenatal care was to avoid having to make several visits to the clinic. Other concerns included fear of encountering wild animals on the way to the clinic as well as lack of money. Fear of caesarean section was reported as a factor hindering intrapartum care-seeking from hospitals. Despite the perceived benefits of postnatal care for children, there was a total lack of postnatal care for the mothers. Shortages of staff, equipment and supplies were common complaints in the community.\ud \ud CONCLUSION\ud \ud Efforts to improve antenatal and postnatal care should focus on addressing geographical and economic access while striving to make services more culturally sensitive. Antenatal and postnatal care can offer important opportunities for linking the health system and the community by encouraging women to deliver with a skilled attendant. Addressing staff shortages through expanding training opportunities and incentives to health care providers and developing postnatal care guidelines are key steps to improve maternal and newborn health
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