613 research outputs found

    Assessment of Environmental Impacts of Limestone Exploitation in Igarra, Nigeria

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    The exploration of limestone is the nerve of socio-economic integration of the Igarra community. However, the exploration activities have been linked with several adverse effects on human health and the deterioration of the surrounding environment. This research work investigates the quality of air in the study area. Dust emission was measured using a digital air quality monitor of model HP 5800D PM2.5-10 with an accuracy of ±5% or ±4ug/m3 and measuring and detection ranges of 0.3 ug/m3 and 0-999.9 ug/m3. The dust level readings using PM2.5 and PM10 at 1 km apart from the three selected exploration sites in Igarra at a 60-minute interval was taken. Quarry one (Q1) recorded the lowest dust level of 20.6 μg//m3 for PM2.5 and 72.5 μg//m3 for PM10 in the early hours before exploration. The general outputs show that exploration sites (Q2) and (Q3) produced a high degree of polluted air than site Q1. A higher dust level of 966.0μg/m3 was recorded for PM10. The overall dust level measurements for PM2.5 and PM10 are higher than the recommended 70.0-80.0 μg/m3 by the World Health Organization (WHO) and the Environmental Protection Agency (EPA). It is projected that continuous emission of dust at Igarra could lead to an increasing number of diseases such as asthma, catarrh, and breathing problems. In conclusion, an integrated exploration mechanism is essential to improve air quality and substantially reduce air related pollution

    Histone deacetylase 11 inhibition promotes breast cancer metastasis from lymph nodes

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    Lymph node (LN) metastases correspond with a worse prognosis in nearly all cancers, yet the occurrence of cancer spreading from LNs remains controversial. Additionally, the mechanisms explaining how cancers survive and exit LNs are largely unknown. Here, we show that breast cancer patients frequently have LN metastases that closely resemble distant metastases. In addition, using a microsurgical model, we show how LN metastasis development and dissemination is regulated by the expression of a chromatin modifier, histone deacetylase 11 (HDAC11). Genetic and pharmacologic blockade of HDAC11 decreases LN tumor growth, yet substantially increases migration and distant metastasis formation. Collectively, we reveal a mechanism explaining how HDAC11 plasticity promotes breast cancer growth as well as dissemination from LNs and suggest caution with the use of HDAC inhibitors

    Surveillance for Zoonotic Pathogens and Inuit Qaujimajatuqangit of Ringed Seals (nattiit) (Pusa hispida) in Frobisher Bay and Eclipse Sound, Nunavut, Canada

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    Ringed seals (Pusa hispida) (nattiq (s.), nattiit (pl.) [Inuktut]) provide an important food staple for Nunavummiut (Indigenous residents of Nunavut). We studied the health of nattiit harvested by hunters from Baffin Island, Nunavut, via Inuit Qaujimajatuqangit and veterinary science. We conducted serological surveys and polymerase chain reaction (PCR) for select zoonotic pathogens, including Brucella spp., Erysipelothrix rhusiopathiae, Leptospira interrogans and Toxoplasma gondii, in 55 nattiit from Frobisher Bay (FB) and 58 nattiit from Eclipse Sound (ES). We used a digestion assay to determine the presence of Trichinella spp. larvae in muscle samples from these seals. We conducted interviews with nine Local Knowledge Holders (LKHs) from Iqaluit (FB) and nine from Pond Inlet (ES) to gather their observations about nattiq health. The hunters evaluate nattiq health through a combination of behavior, nutritional condition, and appearance of skin and organs. They rarely observed severely ill nattiit. Hunters from ES but not from FB observed declining nattiit population numbers. In both regions, they observed increased numbers of harp seals (Phoca groenlandica). Frequencies of natural exposure among nattiit from FB and ES, based on seroprevalence, were 20.5% and 37% for Brucella spp., 25% and 11% for E. rhusiopathiae, 93% and 100% for L. interrogans, and 10% and 27% for T. gondii, respectively; PCR was negative for these pathogens in organs and tissues of seropositive animals. We did not detect larvae of Trichinella spp. Knowledge and experience from the LKHs in assessing nattiq health, complemented by negative findings from direct detection methods, provide reassurance about the safety of nattiit as country food, despite their exposure to some zoonotic pathogens in their natural environment.Les phoques annelés (Pusa hispida) (nattiq (s.), nattiit (pl.) [en inuktut]) constituent une source de nourriture importante pour les Nunavummiut (habitants autochtones du Nunavut). Nous avons étudié l’état de santé des nattiit collectés par les chasseurs de l’île de Baffin, au Nunavut à l’aide de l’Inuit Qaujimajatuqangit et de la science vétérinaire. La sérologie et l’amplification en chaîne par polymérase (PCR) ont été employées pour étudier certains pathogènes susceptibles de causer une zoonose, dont Brucella spp., Erysipelothrix rhusiopathiae, Leptospira interrogans et Toxoplasma gondii, chez 55 nattiit de la baie Frobisher (BF) et 58 nattiit du détroit d’Éclipse (ES). Un test de digestion a été utilisé pour déterminer la présence de larves de Trichinella spp. dans des échantillons de muscle de ces phoques. Nous avons interviewé neuf détenteurs de savoirs locaux (DSL) d’Iqaluit (BF) et neuf DSL de Pond Inlet (ES) afin de recueillir leurs observations sur l’état de santé des nattiit. Les chasseurs évaluent l’état de santé des nattiit à partir de leur comportement, de leur état nutritionnel ainsi que de l’apparence de leur peau et de leurs organes. Ils ont rarement vu des nattiit sévèrement malades. Les chasseurs d’ES ont observé un déclin de la population de nattiit, ce qui n’a pas été le cas des chasseurs de la BF. Dans les deux régions, ils ont observé une augmentation du nombre de phoques du Groenland (Phoca groenlandica). Les fréquences d’exposition naturelle parmi les nattiit de la BF et d’ES, basées sur la séroprévalence, étaient de 20,5 % et de 37 % pour Brucella spp., de 25 % et de 11 % pour E. rhusiopathiae, de 93 % et de 100 % pour L. interrogans et de 10 % et de 27 % pour T. gondii, respectivement. La présence de ces pathogènes dans les tissus et organes d’animaux séropositifs n’a pas été détectée par PCR. Des larves de Trichinella spp. n’ont pas été détectées. Le savoir et l’expérience des DSL pour déterminer l’état de santé des nattiit ainsi que les résultats négatifs obtenus des méthodes de détection directes fournissent une preuve de la salubrité des nattiit comme source de nourriture traditionnelle, malgré le fait qu’ils soient exposés à certains agents pathogènes zoonotiques dans leur milieu naturel

    Regular black holes in quadratic gravity

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    The first-order correction of the perturbative solution of the coupled equations of the quadratic gravity and nonlinear electrodynamics is constructed, with the zeroth-order solution coinciding with the ones given by Ay\'on-Beato and Garc{\'\i}a and by Bronnikov. It is shown that a simple generalization of the Bronnikov's electromagnetic Lagrangian leads to the solution expressible in terms of the polylogarithm functions. The solution is parametrized by two integration constants and depends on two free parameters. By the boundary conditions the integration constants are related to the charge and total mass of the system as seen by a distant observer, whereas the free parameters are adjusted to make the resultant line element regular at the center. It is argued that various curvature invariants are also regular there that strongly suggests the regularity of the spacetime. Despite the complexity of the problem the obtained solution can be studied analytically. The location of the event horizon of the black hole, its asymptotics and temperature are calculated. Special emphasis is put on the extremal configuration

    Ripples in a pond: Do social work students need to learn about terrorism?

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    In the face of heightened awareness of terrorism, however it is defined, the challenges for social work are legion. Social work roles may include working with the military to ensure the well-being of service-men and women and their families when bereaved or injured, as well as being prepared to support the public within the emergency context of an overt act of terrorism. This paper reviews some of the literature concerning how social work responds to confl ict and terrorism before reporting a smallscale qualitative study examining the views of social work students, on a qualifying programme in the UK, of terrorism and the need for knowledge and understanding as part of their education

    Current status of turbulent dynamo theory: From large-scale to small-scale dynamos

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    Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers. It is argued that all the different cases show similarities at intermediate length scales. On the other hand, in the presence of helicity of the turbulence, power develops on large scales, which is not present in non-helical small-scale turbulent dynamos. At small length scales, differences occur in connection with the dissipation cutoff scales associated with the respective value of the magnetic Prandtl number. These differences are found to be independent of whether or not there is large-scale dynamo action. However, large-scale dynamos in homogeneous systems are shown to suffer from resistive slow-down even at intermediate length scales. The results from simulations are connected to mean field theory and its applications. Recent work on helicity fluxes to alleviate large-scale dynamo quenching, shear dynamos, nonlocal effects and magnetic structures from strong density stratification are highlighted. Several insights which arise from analytic considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue "Magnetism in the Universe" (ed. A. Balogh

    Multiwavelength studies of MHD waves in the solar chromosphere: An overview of recent results

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    The chromosphere is a thin layer of the solar atmosphere that bridges the relatively cool photosphere and the intensely heated transition region and corona. Compressible and incompressible waves propagating through the chromosphere can supply significant amounts of energy to the interface region and corona. In recent years an abundance of high-resolution observations from state-of-the-art facilities have provided new and exciting ways of disentangling the characteristics of oscillatory phenomena propagating through the dynamic chromosphere. Coupled with rapid advancements in magnetohydrodynamic wave theory, we are now in an ideal position to thoroughly investigate the role waves play in supplying energy to sustain chromospheric and coronal heating. Here, we review the recent progress made in characterising, categorising and interpreting oscillations manifesting in the solar chromosphere, with an impetus placed on their intrinsic energetics.Comment: 48 pages, 25 figures, accepted into Space Science Review
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