404 research outputs found

    Environmental Predictors of Seasonal Influenza Epidemics across Temperate and Tropical Climates

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    Human influenza infections exhibit a strong seasonal cycle in temperate regions. Recent laboratory and epidemiological evidence suggests that low specific humidity conditions facilitate the airborne survival and transmission of the influenza virus in temperate regions, resulting in annual winter epidemics. However, this relationship is unlikely to account for the epidemiology of influenza in tropical and subtropical regions where epidemics often occur during the rainy season or transmit year-round without a well-defined season. We assessed the role of specific humidity and other local climatic variables on influenza virus seasonality by modeling epidemiological and climatic information from 78 study sites sampled globally. We substantiated that there are two types of environmental conditions associated with seasonal influenza epidemics: “cold-dry” and “humid-rainy”. For sites where monthly average specific humidity or temperature decreases below thresholds of approximately 11–12 g/kg and 18–21°C during the year, influenza activity peaks during the cold-dry season (i.e., winter) when specific humidity and temperature are at minimal levels. For sites where specific humidity and temperature do not decrease below these thresholds, seasonal influenza activity is more likely to peak in months when average precipitation totals are maximal and greater than 150 mm per month. These findings provide a simple climate-based model rooted in empirical data that accounts for the diversity of seasonal influenza patterns observed across temperate, subtropical and tropical climates

    The geoaccumulation index and enrichment factor of mercury in mangrove sediment of Port Klang, Selangor, Malaysia.

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    Mangrove areas are important to the ecosystem. One of its crucial functions is as a sink of pollutants, especially metal ions. However, the accumulation of metals in mangrove sediment can generate negative impacts on plant growth, microbial activity, and soil fertility. Apart from that, the severity of the impact is highly influenced by the type of metal found in the sediment and the quality of sediment itself. One of the metals that have adverse effects on the environment is mercury. The objectives of this study are to determine the concentration and distribution of mercury and to assess the enrichment of mercury in Port Klang mangrove sediment by using geoaccumulation index and enrichment factor. Sediment samples were collected from 30 sampling points that cover Langat River and Klang River estuaries, Lumut Straits, Pulau Klang, and Pulau Indah. During sampling, water parameters such as pH, salinity, electrical conductivity, and total dissolved solids were measured in situ, whereas the total mercury in sediment samples was determined at the laboratory using inductively coupled plasma mass spectrometry. In this study, mercury was found to be concentrated along Lumut Strait especially in the mixing zone near the confluence of Langat River and at the jetty to Pulau Ketam. The geoaccumulation index and enrichment factor (calculated using logarithmized data of the reference element) found that three stations were enriched with mercury. In addition, geoaccumulation index was also observed to be more objective compared to enrichment factor whose results were influenced by the concentration of reference element used

    Evidence for the h_b(1P) meson in the decay Upsilon(3S) --> pi0 h_b(1P)

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    Using a sample of 122 million Upsilon(3S) events recorded with the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we search for the hb(1P)h_b(1P) spin-singlet partner of the P-wave chi_{bJ}(1P) states in the sequential decay Upsilon(3S) --> pi0 h_b(1P), h_b(1P) --> gamma eta_b(1S). We observe an excess of events above background in the distribution of the recoil mass against the pi0 at mass 9902 +/- 4(stat.) +/- 2(syst.) MeV/c^2. The width of the observed signal is consistent with experimental resolution, and its significance is 3.1sigma, including systematic uncertainties. We obtain the value (4.3 +/- 1.1(stat.) +/- 0.9(syst.)) x 10^{-4} for the product branching fraction BF(Upsilon(3S)-->pi0 h_b) x BF(h_b-->gamma eta_b).Comment: 8 pages, 4 postscript figures, submitted to Phys. Rev. D (Rapid Communications

    Independent prognostic value of angiogenesis and the level of plasminogen activator inhibitor type 1 in breast cancer patients

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    Tumour angiogenesis and the levels of plasminogen activator inhibitor type I (PAI-I) are both informative prognostic markers in breast cancer. In cell cultures and in animal model systems, PAI-I has a proangiogenic effect. To evaluate the interrelationship of angiogenesis and the PAI-I level in breast cancer, we have evaluated the prognostic value of those factors in a total of 228 patients with primary, unilateral, invasive breast cancer, evaluated at a median follow-up time of 12 years. Microvessels were immunohistochemically stained by antibodies against CD34 and quantitated by the Chalkley counting technique. The levels of PAI-I and its target proteinase uPA in tumour extracts were analysed by ELISA. The Chalkley count was not correlated with the levels of uPA or PAI-I. High values of uPA, PAI-I, and Chalkley count were all significantly correlated with a shorter recurrence-free survival and overall survival. In the multivariate analysis, the uPA level did not show independent prognostic impact for any of the analysed end points. In contrast, the risk of recurrence was independently and significantly predicted by both the PAI-I level and the Chalkley count, with a hazard ratio (95% CI) of 1.6 (1.01-2.69) and 1.4 (1.02-1.81), respectively. For overall survival, the Chalkley count, but not PAI-I, was of significant independent prognostic value. The risk of death was 1.7 (1,30-2.15) for Chalkley counts in the upper tertile compared to the lower one. We conclude that the PAI-I level and the Chalkley count are independent prognostic markers for recurrence-free survival in patients with primary breast cancer, suggesting that the prognostic impact of PAI-I is not only based on its involvement in angiogenesis. (C) 2003 Cancer Research UK

    Automated Three-Dimensional Detection and Shape Classification of Dendritic Spines from Fluorescence Microscopy Images

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    A fundamental challenge in understanding how dendritic spine morphology controls learning and memory has been quantifying three-dimensional (3D) spine shapes with sufficient precision to distinguish morphologic types, and sufficient throughput for robust statistical analysis. The necessity to analyze large volumetric data sets accurately, efficiently, and in true 3D has been a major bottleneck in deriving reliable relationships between altered neuronal function and changes in spine morphology. We introduce a novel system for automated detection, shape analysis and classification of dendritic spines from laser scanning microscopy (LSM) images that directly addresses these limitations. The system is more accurate, and at least an order of magnitude faster, than existing technologies. By operating fully in 3D the algorithm resolves spines that are undetectable with standard two-dimensional (2D) tools. Adaptive local thresholding, voxel clustering and Rayburst Sampling generate a profile of diameter estimates used to classify spines into morphologic types, while minimizing optical smear and quantization artifacts. The technique opens new horizons on the objective evaluation of spine changes with synaptic plasticity, normal development and aging, and with neurodegenerative disorders that impair cognitive function

    No association between polymorphisms of WNT2 and schizophrenia in a Korean population

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    <p>Abstract</p> <p>Background</p> <p>Wingless-type MMTV integration site family member 2 (WNT2) has a potentially important role in neuronal development; however, there has yet to be an investigation into the association between single nucleotide polymorphisms (SNPs) of <it>WNT2 </it>and schizophrenia. This study aimed to determine whether certain SNPs of <it>WNT2 </it>were associated with schizophrenia in a Korean population.</p> <p>Methods</p> <p>e genotyped 7 selected SNPs in the <it>WNT2 </it>gene region (approximately 46 Kb) using direct sequencing in 288 patients with schizophrenia and 305 healthy controls.</p> <p>Results</p> <p>Of the SNPs examined, one SNP showed a weak association with schizophrenia (p = 0.017 in the recessive model). However, this association did not remain statistically significant after Bonferroni correction.</p> <p>Conclusion</p> <p>The present study does not support a major role for <it>WNT2 </it>in schizophrenia. This could be due to the size of the population. Therefore, additional studies would be needed to definitively rule out the gene's minor effects.</p

    Synaptic Reorganization in the Adult Rat's Ventral Cochlear Nucleus following Its Total Sensory Deafferentation

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    Ablation of a cochlea causes total sensory deafferentation of the cochlear nucleus in the brainstem, providing a model to investigate nervous degeneration and formation of new synaptic contacts in the adult brain. In a quantitative electron microscopical study on the plasticity of the central auditory system of the Wistar rat, we first determined what fraction of the total number of synaptic contact zones (SCZs) in the anteroventral cochlear nucleus (AVCN) is attributable to primary sensory innervation and how many synapses remain after total unilateral cochlear ablation. Second, we attempted to identify the potential for a deafferentation-dependent synaptogenesis. SCZs were ultrastructurally identified before and after deafferentation in tissue treated for ethanolic phosphotungstic acid (EPTA) staining. This was combined with pre-embedding immunocytochemistry for gephyrin identifying inhibitory SCZs, the growth-associated protein GAP-43, glutamate, and choline acetyltransferase. A stereological analysis of EPTA stained sections revealed 1.11±0.09 (S.E.M.)×109 SCZs per mm3 of AVCN tissue. Within 7 days of deafferentation, this number was down by 46%. Excitatory and inhibitory synapses were differentially affected on the side of deafferentation. Excitatory synapses were quickly reduced and then began to increase in number again, necessarily being complemented from sources other than cochlear neurons, while inhibitory synapses were reduced more slowly and continuously. The result was a transient rise of the relative fraction of inhibitory synapses with a decline below original levels thereafter. Synaptogenesis was inferred by the emergence of morphologically immature SCZs that were consistently associated with GAP-43 immunoreactivity. SCZs of this type were estimated to make up a fraction of close to 30% of the total synaptic population present by ten weeks after sensory deafferentation. In conclusion, there appears to be a substantial potential for network reorganization and synaptogenesis in the auditory brainstem after loss of hearing, even in the adult brain

    Embedding cultural competence in faculty : a mixed-methods evaluation of an applied Indigenous proficiency workshop

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    One of the most pressing issues in Australian society is the gap between Indigenous and non-Indigenous health and life expectancies (Marmot, 2017). Australia agreed with the World Health Organisation’s 2008 Closing the Gap in a Generation report (WHO, 2008), spending approximately 5.6% of government expenditure towards ameliorating this gap (Gardiner-Garden & Simon-Davies, 2012), yet there have been only minimal positive outcomes (Alford, 2015; Gannon, 2018). In applied terms, this means Indigenous people are still dying younger (Anderson et al., 2016), scoring higher on psychological distress (Markwick, Ansari, Sullivan, & McNeil, 2015) and suffering poorer indices on all chronic diseases (e.g. Walsh & Kangaharan, 2016; Thompson, Talley, & Kong, 2017). The level of complexity involved in addressing these “wicked” or seemingly “impossible to solve” health problems is made worse by the lack of any pan-national strategic planning and/or intervention evaluation (Lokuge et al., 2017), even though there has been a plethora of programs and projects designed to improve Indigenous health (see for example, AGPC, 2016). Leaders in health and educational institutions must consider why there is a lack of progress in closing the gap in Indigenous health and life expectancies. Addressing the inequities in Indigenous health requires a determinant of health approach (Mitrou et al., 2014), as 39% of the gap in health outcomes can be explained by social determinates (AIHW, 2017; Markwick, Ansari, Sullivan, Parsons, & McNeil, 2014). The social determinant considered to most reliably predict Indigenous poor health is racism (Kelaher, Ferdinand, & Paradies, 2014; Paradies, 2006; Paradies & Cunningham, 2009; Paradies et al., 2015; Paradies, Truong, & Priest, 2014)
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