135 research outputs found

    Astrapotheres from Cañadón Vaca, middle Eocene of central Patagonia: New insights on diversity, anatomy, and early evolution of Astrapotheria

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    Astrapotheria is one of the most emblematic groups of endemic South American ungulate-like extinct mammals, traditionally compared with modern tapirs and rhinos. Oldest astrapotheres are known from the early Eocene Itaboraian fauna (Brazil), but the earliest diverse astrapothere assemblage is known from the middle Eocene Cañadón Vaca Member of the Sarmiento Formation exposed at Cañadón Vaca (Vacan subage of the Casamayoran Land Mammal Age), in central Patagonia, Argentina. Previous reports of astrapotheres from Cañadón Vaca included Trigonostylops, Tetragonostylops, Albertogaudrya, and Scaglia, but only the record of the latter was unequivocal. New materials from Cañadón Vaca described herein confirms the occurrence of Trigonostylops (T. wortmani) and of Tetragonostylops (likely represented by a species different from the nominal species from Itaboraí). Additionally, two other taxa are identified: The former, described as cf. Scaglia cf. kraglievichorum, is represented by a partial skull with an unusual combination of cranial characters, and could correspond to an adult of Scaglia kraglievichorum (known by a juvenile skull); the other taxon is represented by a partial mandible with distinctive osteological and dental features, but the possibility of its belonging to Scaglia cannot be discarded. The occurrence of Albertogaudrya in Cañadón Vaca could not be confirmed by the examination of the new and previous collections. Astrapotheres from Cañadón Vaca show a wide morphological disparity of cranial designs, but all consistently share long, unreduced nasals, thus the presumed possession of a short tapir-like proboscis only typifies the post-Casamayoran astrapotheres.Fil: Kramarz, Alejandro Gustavo. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico de Paleontología de Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Bond, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Carlini, Alfredo Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentin

    Predation on cephalopods by Pygoscelis papua and Arctocephalus gazelle at south Orkney Islands

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    The cephalopod diet of the gentoo penguin, Pygoscelis papua and the Ant− arctic fur seal, Arctocephalus gazella was comparatively analyzed at Laurie Island, South Orkney Islands. A total of 125 stomach samples were collected by the water off−loading method from gentoo penguins during the autumns of 1993, 1995 and 1996, and 39 fur seal scats were collected from mid March to April 1988. Cephalopods preyed upon by gentoo penguins were represented by 1974 beaks (1628 lower, 346 upper) which occurred in 50.4% of the samples. Lower beaks identified belonged exclusively to the squid Psychroteuthis glacialis. The mean lower rostral length (LRL) of these beaks was 1.1 mm (range 0.4– 1.8 mm). From the Antarctic fur seal scats 103 beaks (41 lower, 62 upper) were removed from 60.6% of scats which contained prey remains. The cephalopod species identified were Slosarczykovia circumantarctica and P. glacialis which constituted 78.8% and 21.1% in terms of numbers, respectively. The mean lower rostral length for S. circumantarctica was 2.7 mm (range 2.0–3.5 mm), while that of P. glacialis was 1.6 mm (range 1.0–2.5 mm). The foraging behaviour of the two top predators was analyzed and discussed according to the composition and size of their cephalopod prey

    Hemorragias cerebro-meníngeas del recién nacido

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    Geographical variation in the diet of the Antarctic fur seal <i>Arctocephalus gazella</i>

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    The diet of non-breeding male Antarctic fur seals Arctocephalus gazella was investigated at different localities of the Antarctic Peninsula (Cierva Point and Hope Bay), South Shetland Islands (Deception Island and Potter Peninsula) and the South Orkney Islands (Laurie Island), by the analysis of 438 scats collected from January to March 2000. The composition of the diet was diverse, with both pelagic and benthic-demersal prey represented in the samples. Antarctic krill Euphausia superba was the most frequent and numerous prey at all the study sites except at Cierva Point, followed by fish, penguins and cephalopods. Antarctic krill also predominated by mass, followed by either fish or penguins. Fish were the second most important prey by mass at the Antarctic Peninsula whereas penguins were the second most important prey by mass at the South Shetland and South Orkney Islands. Among fish, Pleuragramma antarcticum was the most important species in the diet of the Antarctic fur seals at the Antarctic Peninsula whereas Gymnoscopelus nicholsi predominated at the South Shetland and South Orkney Islands. The results are compared with previous studies, and the possibility of implementing monitoring studies on the distribution/abundance of myctophids and P. antarcticum based on the analysis of the diet of the Antarctic fur seal is considered.Facultad de Ciencias Naturales y MuseoFacultad de Ciencias Médica

    Better late than never? Interannual and seasonal variability in breeding chronology of gentoo penguins at stranger point, Antarctica

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    Rapid climate change recorded in the western Antarctic Peninsula confronts species with less predictable conditions in the marine and terrestrial environments. We analysed the breeding chronology and nesting site selection of gentoo penguins (Pygoscelis papua) at King George Island (Isla 25 de Mayo), Antarctica, during four seasons in which differences in snow presence and persistence on the ground were observed. We recorded an overall delay as well as seasonal asynchrony at the beginning of reproduction for those years with higher snow deposition. A redistribution of breeding groups was also observed. Nevertheless, the population breeding success and chicks' weight at fledging remained relatively constant, despite the delay in breeding chronology, the increased duration of foraging trips during the guard stage and the decreased weight of stomach contents during the cre'che stage. We suggest that the plasticity of their trophic biology, along with the flexibility of their breeding phenology and relocation of breeding groups, may be complementary reasons why gentoo penguin populations in the region have remained stable in spite of the changing conditions currently registered.Facultad de Ciencias Naturales y MuseoInstituto Multidisciplinario de Biología Celula

    Aves, Charadriiformes, Scolopacidae, Limosa haemastica (Linnaeus, 1758): first record from South Shetland Islands and Antarctic Peninsula, Antarctica

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    We report herein the southernmost record of the Hudsonian Godwit (Limosa haemastica), at two localities in the Antarctic: Esperanza/Hope Bay (January 2005) and 25 de Mayo/King George Island (October 2008). On both occasions a pair of specimens with winter plumage was observed

    Antarctic radiocarbon reservoir: the case of the mummified crabeater seals (<i>Lobodon Carcinophaga</i>) in Bodman Cape, Seymour Island, Antarctica

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    At least 50% of the world's seal population is distributed in the pack-ice region surrounding Antarctica. Among the Antarctic seals, Lobodon carcinophaga (commonly known as "crabeater seals") are the most abundant. This is a krill-feeding species, subsisting primarily on Euphausia superba. The occurrence of mummified seals has been documented since 1900 in several Antarctic regions, and different hypotheses about age and what happened to them have been proposed. Taking into account the depletion of 14C concentration in marine waters, we dated a recently deceased and a mummified L. carcinophaga along with a mollusk (Nacella concinna) collected alive from different locations around Antarctica. We discuss their relationship in light of the 14C reservoir. The age obtained for the recently deceased crabeater seals suggests a reservoir age of around 1300 yr for these waters, which is in agreement with the correction value for reservoir age obtained for the same species in the area. We applied this reservoir correction value to the conventional age of 1180 14C yr BP obtained for the mummified seal. The results indicate that the death event probably occurred within the last 100 yr. The age obtained for the mollusk specimen confirms that the correction values of the reservoir effect for the Antarctic continent vary according to geographical location and to the type of sample dated.Museo de La Plat

    Better late than never? Interannual and seasonal variability in breeding chronology of gentoo penguins at Stranger Point, Antarctica

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    Rapid climate change recorded in the western Antarctic Peninsula confronts species with less predictable conditions in the marine and terrestrial environments. We analysed the breeding chronology and nesting site selection of gentoo penguins (Pygoscelis papua) at King George Island (Isla 25 de Mayo), Antarctica, during four seasons in which differences in snow presence and persistence on the ground were observed. We recorded an overall delay as well as seasonal asynchrony at the beginning of reproduction for those years with higher snow deposition. A redistribution of breeding groups was also observed. Nevertheless, the population breeding success and chicks' weight at fledging remained relatively constant, despite the delay in breeding chronology, the increased duration of foraging trips during the guard stage and the decreased weight of stomach contents during the cre'che stage. We suggest that the plasticity of their trophic biology, along with the flexibility of their breeding phenology and relocation of breeding groups, may be complementary reasons why gentoo penguin populations in the region have remained stable in spite of the changing conditions currently registered.Facultad de Ciencias Naturales y MuseoInstituto Multidisciplinario de Biología Celula

    Several Polymorphisms of KCNQ1 Gene Are Associated with Plasma Lipid Levels in General Chinese Populations

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    BACKGROUND: Potassium voltage-gated channel, KQT-like subfamily, member 1 (KCNQ1) is thought to be an important candidate gene of diabetes. Several single nucleotide polymorphisms (SNPs) in a 40-kb linkage disequilibrium (LD) block in its intron 15 have been identified to be associated with diabetes in East Asian populations in recent genome-wide association studies. The aim of this study was to investigate whether KCNQ1 polymorphisms influence the levels of the metabolic phenotypes in general Chinese populations. METHODOLOGY/PRINCIPAL FINDINGS: We investigated the associations of two SNPs (rs2237892 and rs2237895) in the aforementioned 40-kb LD block, a missense variant rs12720449 (P448R) in exon 10, and a synonymous variant rs1057128 (S546S) in exon 13 with metabolic phenotypes in a Uyghur population (n = 478) and replicated these associations in a Han population (n = 2,485). We found that rs2237892-T allele was significantly associated with decreased triglyceride levels (p(combined) = 0.001). The minor G allele of the rs12720449, with sharp difference of the allelic frequency between European and East Asian populations (0.2% versus 14%, respectively), was associated with a lower triglyceride levels than G allele in Uyghur subjects (p = 0.004), in Han subjects (p = 0.052), and in subjects of meta-analysis (p(combined) = 0.001). Moreover, the minor A allele of the rs1057128 was also associated with decreased triglyceride levels in meta-analysis (p(combined) = 0.010). CONCLUSIONS: To the best of our knowledge, this is the first report associating a missense mutation of KCNQ1, rs12720449, with triglyceride levels. Rs2237892, representing the 40-kb LD block, is also associated with triglyceride levels in Han population. Further studies are required to replicate these findings in other East Asian populations

    Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

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    Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research
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