154 research outputs found

    Diversity of the Ant Genus Neoponera Emery, 1901 (Formicidae: Ponerinae) in the north of the Brazilian Atlantic Forest, with new Records of Occurrence

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    Composed of two main forest formations, Ombrophilous Forest and Seasonal Forest, the Brazilian Atlantic Forest biome is constituted currently by a mosaic of forest remnants and secondary vegetation. Representatives of the Ponerinae ant genus Neoponera are observed mainly in both wet and seasonally dry forests. The aim of this study was to approach the diversity of the genus Neoponera in the north of the Atlantic Forest of Brazil (from the extreme north of its distribution to the Doce River hydrographic basin in the south), associating the occurrence of ant species with the types of vegetation. We have compiled occurrence data from the collection of the Myrmecology Laboratory of the Cocoa Research Center, on internet, or available in literature. We found information on 23 species of Neoponera, including a new record for the Atlantic Forest, Neoponera globularia (Mackay & Mackay, 2010), and a new record for Brazil, Neoponera fiebrigi Forel, 1912. The relative composition of the Neoponera assemblages was evaluated according to the types of vegetation. We found that the occurrence of the genus Neoponera is mainly related to the types of vegetation of the focus region, principally dense forests where a higher diversity was observed

    Hybrid silicon evanescent approach to optical interconnects

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    We discuss the recently developed hybrid silicon evanescent platform (HSEP), and its application as a promising candidate for optical interconnects in silicon. A number of key discrete components and a wafer-scale integration process are reviewed. The motivation behind this work is to realize silicon-based photonic integrated circuits possessing unique advantages of III–V materials and silicon-on-insulator waveguides simultaneously through a complementary metal-oxide semiconductor fabrication process. Electrically pumped hybrid silicon distributed feedback and distributed Bragg reflector lasers with integrated hybrid silicon photodetectors are demonstrated coupled to SOI waveguides, serving as the reliable on-chip single-frequency light sources. For the external signal processing, Mach–Zehnder interferometer modulators are demonstrated, showing a resistance-capacitance-limited, 3 dB electrical bandwidth up to 8 GHz and a modulation efficiency of 1.5 V mm. The successful implementation of quantum well intermixing technique opens up the possibility to realize multiple III–V bandgaps in this platform. Sampled grating DBR devices integrated with electroabsorption modulators (EAM) are fabricated, where the bandgaps in gain, mirror, and EAM regions are 1520, 1440 and 1480 nm, respectively. The high-temperature operation characteristics of the HSEP are studied experimentally and theoretically. An overall characteristic temperature (T 0) of 51°C, an above threshold characteristic temperature (T 1) of 100°C, and a thermal impedance (Z T ) of 41.8°C/W, which agrees with the theoretical prediction of 43.5°C/W, are extracted from the Fabry–Perot devices. Scaling this platform to larger dimensions is demonstrated up to 150 mm wafer diameter. A vertical outgassing channel design is developed to accomplish high-quality III–V epitaxial transfer to silicon in a timely and dimension-independent fashion

    A Long-Term Vision for an Ecologically Sound Platte River

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    The Platte River extends about 310 mi (499 km) from North Platte, Nebraska, to its terminus at the Missouri River confluence near Plattsmouth, Nebraska. The Platte River Valley is a continentally significant ecosystem that serves as a major stopover for migratory waterbirds in the Central Flyway including the endangered Whooping Crane (Grus americana) and \u3e1 million Sandhill Cranes (Antigone canadensis) at the peak of spring migration. However, the Platte River Valley also supports a great diversity of avifauna including grassland breeding birds, native stream fish, vascular plants, herpetofauna, mammals, pollinators, and aquatic macroinvertebrates. Despite ongoing conservation efforts since the mid-1970s the ecosystem remains largely conservation dependent and an increasing number of species across taxa are being considered at risk of regional extirpation or outright extinction. However, given the attention provided to conservation in the Platte River Valley and the need to maintain ecologically functional stopover sites in the Central Flyway, there is a great opportunity to create a resilient refugium for biodiversity conservation in the central Great Plains. To that end we convened a working group of \u3e18 individuals representing \u3e9 organizations including representatives from non-profit conservation organizations, universities, and state and federal natural resource agencies to develop a long-term vision for an ecologically sound Platte River Valley (PRV). We met in groups of varying size for \u3e170 hours throughout a more than 3-year period and developed conservation priorities and objectives using a landscape design process. Landscape design is an interdisciplinary conservation planning process that incorporates components of landscape ecology and social dimensions of natural resources with the explicit intention of improving conservation implementation.https://digitalcommons.unl.edu/zeabook/1128/thumbnail.jp

    IFN-γ– and IL-10–expressing virus epitope-specific Foxp3+ T reg cells in the central nervous system during encephalomyelitis

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    Pathogen-specific Foxp3+ T reg cells can be identified on the basis of cytokine production, are detected in naive T cell populations, and exhibit suppressive ability toward effector T cells with the same antigen specificity

    Symbiotic organs shaped by distinct modes of genome evolution in cephalopods.

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    Microbes have been critical drivers of evolutionary innovation in animals. To understand the processes that influence the origin of specialized symbiotic organs, we report the sequencing and analysis of the genome of Euprymna scolopes, a model cephalopod with richly characterized host-microbe interactions. We identified large-scale genomic reorganization shared between E. scolopes and Octopus bimaculoides and posit that this reorganization has contributed to the evolution of cephalopod complexity. To reveal genomic signatures of host-symbiont interactions, we focused on two specialized organs of E. scolopes: the light organ, which harbors a monoculture of Vibrio fischeri, and the accessory nidamental gland (ANG), a reproductive organ containing a bacterial consortium. Our findings suggest that the two symbiotic organs within E. scolopes originated by different evolutionary mechanisms. Transcripts expressed in these microbe-associated tissues displayed their own unique signatures in both coding sequences and the surrounding regulatory regions. Compared with other tissues, the light organ showed an abundance of genes associated with immunity and mediating light, whereas the ANG was enriched in orphan genes known only from E. scolopes Together, these analyses provide evidence for different patterns of genomic evolution of symbiotic organs within a single host

    Cross-National Differences in Victimization : Disentangling the Impact of Composition and Context

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    Varying rates of criminal victimization across countries are assumed to be the outcome of countrylevel structural constraints that determine the supply ofmotivated o¡enders, as well as the differential composition within countries of suitable targets and capable guardianship. However, previous empirical tests of these ‘compositional’ and ‘contextual’ explanations of cross-national di¡erences have been performed upon macro-level crime data due to the unavailability of comparable individual-level data across countries. This limitation has had two important consequences for cross-national crime research. First, micro-/meso-level mechanisms underlying cross-national differences cannot be truly inferred from macro-level data. Secondly, the e¡ects of contextual measures (e.g. income inequality) on crime are uncontrolled for compositional heterogeneity. In this paper, these limitations are overcome by analysing individual-level victimization data across 18 countries from the International CrimeVictims Survey. Results from multi-level analyses on theft and violent victimization indicate that the national level of income inequality is positively related to risk, independent of compositional (i.e. micro- and meso-level) di¡erences. Furthermore, crossnational variation in victimization rates is not only shaped by di¡erences in national context, but also by varying composition. More speci¢cally, countries had higher crime rates the more they consisted of urban residents and regions with lowaverage social cohesion.

    Role of TGF-β1 haplotypes in the occurrence of myocardial infarction in young Italian patients

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    <p>Abstract</p> <p>Background</p> <p>Transforming growth factor beta 1 (TGF-β1) gene play an important role in the acute myocardial infarction (AMI), however no investigation has been conducted so far in young AMI patients.</p> <p>In this study, we evaluated the influence of TGF-β1 polymorphisms/haplotypes on the onset and progression of AMI in young Italian population.</p> <p>Methods</p> <p>201 cases and 201 controls were genotyped for three TGF-β1 polymorphisms (G-800A, C-509T and Leu10Pro). The main follow-up end-points (mean follow-up, 107 ± 49 months) were death, myocardial infarction or revascularization procedures.</p> <p>Results</p> <p>Significant risk factors were smoking (p < 10<sup>-4</sup>), family history for coronary artery disease (p < 10<sup>-4</sup>), hypercholesterolemia (p = 0.001) and hypertension (p = 0.002). The C-509T and Leu10Pro polymorphisms showed significant differences (p = 0.026 and p = 0.004) between cases and controls.</p> <p>The most common haplotypes revealed a possible protective effect (GCT, OR 0.75, 95% CI 0.57–0.99, p = 0.042) and an increased risk of AMI (GTC, OR 1.51, 95% CI 1.13–2.02, p = 0.005), respectively.</p> <p>No statistical differences were observed in genotype distribution in the follow-up study between the two groups: 61 patients with subsequent events (13 deaths) and 108 without events.</p> <p>Conclusion</p> <p>Even though our results need to be further confirmed in larger studies, this is the first study reporting on a possible role of TGFβ1 common haplotypes in the onset of AMI in young patients.</p

    Left and right ventricle assessment with Cardiac CT: validation study vs. Cardiac MR

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    Objectives To compare Magnetic Resonance (MR) and Computed Tomography (CT) for the assessment of left (LV) and right (RV) ventricular functional parameters. Methods Seventy nine patients underwent both Cardiac CT and Cardiac MR. Images were acquired using short axis (SAX) reconstructions for CT and 2D cine b-SSFP (balanced- steady state free precession) SAX sequence for MR, and evaluated using dedicated software. Results CT and MR images showed good agreement: LV EF (Ejection Fraction) (52±14% for CT vs. 52±14% for MR; r0 0.73; p>0.05); RV EF (47±12% for CT vs. 47±12% for MR; r00.74; p>0.05); LV EDV (End Diastolic Volume) (74± 21 ml/m 2 for CT vs. 76±25 ml/m 2 for MR; r00.59; p>0.05); RV EDV (84±25 ml/m 2 for CT vs. 80±23 ml/m 2 for MR; r0 0.58; p>0.05); LV ESV (End Systolic Volume)(37±19 ml/m 2 for CT vs. 38±23 ml/m 2 for MR; r00.76; p>0.05); RV ESV (46±21 ml/m 2 for CT vs. 43±18 ml/m 2 for MR; r00.70; p>0.05). Intra- and inter-observer variability were good, and the performance of CT was maintained for different EF subgroups. Conclusions Cardiac CT provides accurate and reproducible LVand RV volume parameters compared with MR, and can be considered as a reliable alternative for patients who are not suitable to undergo MR. Key Points • Cardiac-CT is able to provide Left and Right Ventricular function. • Cardiac-CT is accurate as MR for LV and RV volume assessment. • Cardiac-CT can provide accurate evaluation of coronary arteries and LV and RV function
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