Challenges of Addressing Environmental Problems due to Quarrying Operation in Uwandani Ward, Pemba

This paper examines the challenges of addressing environmental challenges arising from aggregates quarrying at Uwandani Ward in Pemba, Zanzibar. Specifically, the study examines i) the socio-economic importance of quarrying, ii) the environmental impacts, iii) the interventions done to address environmental problems, and iv) the constraints over interventions. Data collection methods included household questionnaire survey, key informants interviews and participant observations. Statistical Package for Social Sciences (SPSS) and content analysis techniques were used in the analysis and processing of quantitative and qualitative data. The findings showed that although the revenue generated from quarrying operation is crucial for the livelihood of the local people, persistent environmental problems have been difficult to address due to lack of education, poverty, rapid increase of quarrying operations, drought and climate change variability, apathy in the community and inferior technology used in the quarrying operations. Furthermore, the challenges of tackling environmental problems are contributed by unsuccessful piecemeal interventions of the government because of the lack of clear recognition and appreciation of the artisanal quarrying operation contribution in the livelihood of local people. This paper recommends that the government recognizes and appreciates informal quarrying operations in order to put effective policies to develop the sector and address its environmental problems. This should be accompanied by the participation of all stakeholders in planning and implementation to address environmental problems through bottom-up approaches

Development and validation of a mathematical model for ventilation rate in crop protection structures

Natural ventilation is defined as the number of air exchanges per hour per unit floor area necessary to reduce high indoor air temperature and humidity. In addition, it maintains the concentration of carbon dioxide. Natural ventilation is preferred in mechanical system as the ventilation opening is built into the greenhouse, with lower construction cost and no energy and maintenance inputs are required. A mathematical model to quantify natural ventilation rates was developed and verified in large-scale greenhouse structures. For this purpose, four Naturally Ventilated Tropical Greenhouse Structures were designed and constructed at the Malaysian Agricultural Research and Development Institute (MARDI). These were single, double, triple, and quadruple span structures with floor areas of 500 m2, 1000 m2, 1500 m2 and 2000 m2, respectively. This paper presents the validation of a mathematical model which was developed to quantify natural ventilation rates which are very crucial to reduce high in-house temperature built up in the tropics. Regression equations of natural ventilation against wind speed were found to be Φw = 0.0632V, Φw= 0.0395V, Φw= 0.0316V and Φw= 0.0276V for the single, double, triple and quadruple spans, respectively. Meanwhile, coefficients of determination showed strong relationships between ventilation rate and wind speed, with R2 = 0.9999 for all structures. Larger floor area was found to have higher in-house temperature than smaller ones. Ventilation rate inside the single-span structure was found to be higher compared to the multi-span structures, which increased linearly with the increasing wind speed at the eaves of structure

The effect of ethical leadership on management accountants’ performance: the mediating role of psychological well-being

This paper examined the impacts imparted by ethical leadership on both the performance and well-being of management accountants employed in public shareholding companies operating in Jordan. The mediating effect of psychological well-being was also examined. In testing the study hypotheses, analysis was performed on 93 obtained responses. The structural equation modeling (SEM) approach was used. From the outcomes, the ethical leadership level has significant impact on the psychological well-being of management accountants, while ethical leadership indirectly and significantly affects job performance, but only by way of psychological well-being. All these lend support to the mediating role of the psychological well-being of employees in the delineation of the link existing between ethical leadership and employee performance. Limitations and implications of the study are discussed. The directions of forthcoming studies are proposed as well

Causal Model of the Association between Academic Burnout and Achievement Goals: The Intermediating Role of Self-Efficacy and Procrastination

Background & Objective: There has been growing recognition that medical students, interns, residents, and practicing physicians across many specialties are prone to burnout, with recent studies linking high rates of burnout to adverse mental health issues. The aim of this study was to examine factors affecting academic burnout among medical students and investigate the association between achievement goals and its dimensions, academic self-efficacy, and academic procrastination in the form of a causal model. Methods: For this purpose, 174 students (98 in the clinical stage and 76 in the preclinical stage) of Shiraz University of Medical Sciences (Iran) were selected based on Cochran’s Formula and through simple random sampling. The data collection tools consisted of the Maslach Burnout Inventory-Student Survey (MBI-SS), Achievement Goal Questionnaire (Elliot and McGregor), Academic Self-Efficacy Scale (Midgley et al.), and Academic Procrastination Scale (Savari). To analyze the data, path analysis and the Pearson correlation coefficient were used. Results: The resulting path models indicated that academic burnout had significant negative relationships with mastery achievement goal, performance-approach, and academic self-efficacy, but it had significantly positive relationships with academic procrastination and performanceavoidance. It was also found that achievement goals had impact on academic burnout through academic procrastination and self-efficacy. The explained variance of academic burnout was 0.61. Conclusion: It was found that achievement goals and academic self-efficacy had significant effects on academic procrastination and burnout. Thus, it is suggested that those involved in education provide the students with situations in which they can achieve a higher sense of empowerment in learning, so that they become more engaged in their academic work and be less likely to experience burnout. Key Words: Academic burnout, Achievement goals, Academic self-efficacy, Academic procrastinatio

Umbelliferone inhibits spermatogenic defects and testicular injury in lead-intoxicated rats by suppressing oxidative stress and inflammation, and improving Nrf2/HO-1 signaling

© 2020 Alotaibi et al. Introduction: Lead (Pb) is an environmental toxic metal that threatens human health. Umbelliferone (UMB) is a coumarin with known medicinal and protective properties against cytotoxicity. This study explored the ameliorative effect of UMB against Pb-induced testicular toxicity in rats, focusing on steroidogenesis, oxidative stress and inflammation. Materials and Methods: Rats received lead acetate (50 mg/kg) and UMB (25, 50 or 100 mg/kg) via oral gavage for 4 weeks. Results: Pb-intoxicated rats exhibited testicular tissue injury and decreased serum levels of LH, FSH and testosterone. The count, viability, motility and normal morphology of the sperms were decreased accompanied with downregulated steroidogenesis markers in Pbinduced group. UMB prevented testicular injury, increased serum levels of LH, FSH and testosterone, upregulated steroidogenesis markers and improved the semen quality. In addition, UMB attenuated oxidative stress and oxidative DNA damage, downregulated the expression of pro-inflammatory mediators and Bax, boosted antioxidant defenses and Bcl2, and upregulated Nrf2/HO-1 signaling in Pb-intoxicated rats. Conclusion: UMB prevents Pb-induced testicular injury by suppressing oxidative damage, inflammation and cell death, and boosting antioxidant defenses, Nrf2/HO-1 signaling and pituitary-gonadal axis. Thus, UMB may represent a protective and cost-effective agent against Pb testicular toxicity, pending further investigations to elucidate other underlying mechanisms.Open Access funding provided by the Qatar National Library

Polymorphisms in the bovine HSP90AB1 gene are associated with heat tolerance in Thai indigenous cattle

Heat shock proteins act as molecular chaperones that have preferentially been transcribed in response to severe perturbations of the cellular homeostasis such as heat stress. Here the traits respiration rate (RR), rectal temperature (RT), pack cell volume (PCV) and the individual heat tolerance coefficient (HTC) were recorded as physiological responses on heat stress (environmental temperatures) in Bos taurus (crossbred Holstein Friesian; HF) and B. indicus (Thai native cattle: White Lamphun; WL and Mountain cattle; MT) animals (n = 47) in Thailand. Polymorphisms of the heat shock protein 90-kDa beta gene (HSP90AB1) were evaluated by comparative sequencing. Nine single nucleotide polymorphisms (SNP) were identified, i.e. three in exons 10 and 11, five in introns 8, 9, 10 and 11, and one in the 3′UTR. The exon 11 SNP g.5082C>T led to a missense mutation (alanine to valine). During the period of extreme heat (in the afternoon) RR and RT were elevated in each of the three breeds, whereas the PCV decreased. Mountain cattle and White Lamphun heifers recorded significantly better physiologic parameters (p < 0.05) in all traits considered, including or particularly HTC than Holstein Friesian heifers. The association analysis revealed that the T allele at SNP g.4338T>C within intron 3 improved the heat tolerance (p < 0.05). Allele T was exclusively found in White Lamphun animals and to 84% in Mountain cattle. Holstein Friesian heifers revealed an allele frequency of only 18%. Polymorphisms within HSP90AB1 were not causative for the physiological responses; however, we propose that they should at least be used as genetic markers to select appropriate breeds for hot climates

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum