575 research outputs found
21-Hydroxypregna-1,4-diene-3,20-dione
The title compound, C21H28O3, is a fungal transformed metabolite of decoxycorticosterone acetate, consisting of four fused rings A, B, C and D. Ring A is nearly planar, with a maximum deviation of 0.010 (3) Å from the least-squares plane, while the trans-fused rings B and C adopt chair conformations. The five-membered ring D is in an envelope conformation. The orientation of the side chain is stabilized by an intramolecular O—H⋯O hydrogen bond. In the crystal, adjecent molecules are linked by C—H⋯O hydrogen bonds into extended zigzag chains along the a axis
Local perception of indoor air pollution with use of biofuel in rural communities of Uchalli Wetlands complex, salt range Pakistan
More than 2.4 billion people around the world in the rural community depend on biomass fuel (wood, charcoal animal dung, and crop residue). Incomplete combustion of this fuel has led to increased amounts of indoor pollution and raise in global warming; this has further led to the increase in the incidence of diseases. Therefore, interventions to reduce biomass fuel related emission by alternative fuels and improved combustion efficiency can improve health, add to socioeconomic development. The area selected for sampling was the Uchalli Wetlands Complex which in the Northwest of Khushab district in Pakistan which houses three saline lakes surrounded by forest and villages. A questionnaire was designed with questions regarding the household fuel use and techniques to improve livelihood and to create awareness and locals from the age of 19-95 were interviewed with a majority of males, houses in the area were mainly of stone blocks and majority males in the area worked in the city. Combined family system was prevalent in the area (80%) with about 42% of the population having no formal education. A wide variety of stoves were observed in the area with wives having a major decision (69%) in fuel choice which mainly depended on the cheapness and availability of the fuel. The cooking being mostly done (79.8%) outside in summers and indoors in winters. Majority of the respondents (94.7%) were aware that liquid petroleum gas and natural gas are better ways of reducing pollution and decreasing the incidence of diseases which included using dry wood, proper ventilation and many others
Directionally solidified cobalt-doped MgO-MgAl2O4 eutectic composites for selective emitters
Cobalt-doped MgO-MgAl2O4 eutectic composites were explored for their use as selective emitters for thermophotovoltaic devices. Eutectic ceramic rods with different cobalt content were directionally solidified by using the laser floating zone technique at two processing rates to obtain microstructures with different domain sizes. Thermal emission between 1000 °C and 1500 °C and optical properties (reflectance and transmittance) at room temperature were measured in the Co-doped composites and the effect on microstructure and cobalt content was investigated. Thermal emission consisted of an intense broad band at about 1.67 µm matching with the bandgap of the InGaAs cell. The emission was ascribed to the de-excitation from the 4T1(F) multiplet to the 4A2(F) ground state of the thermally excited Co ions located in the tetrahedral sites of the MgAl2O4 phase. The selectivity of the thermal emission showed a decrease with the cobalt content due to the enhancement of other electronic transitions, which leads to keeping the cobalt content in these composites at low levels (<0.15% at Co) for their use as selective emitters
A Reflexive Autoethnography of Doctoral Supervision: Lone Mother, Lone Researcher
This article traces elements of the learning of a doctoral student. It concerns attempts to bridge a number of gaps between supervisor and student in the process of studying for a Ph.D. In particular, it portrays differences in culture, gender, family, age and experience and how those differences influenced the thinking of the student. A layered discourse of readings, misreadings and re-readings is developed, drawing on the substantive literature on ‘lone motherhood’, on studies of doctoral supervision and on anthropological insights into the nature of cultural differences. It is a case study in finding the ‘missing’ (or not yet known) person who is the lone mother and the lone researcher who ‘reveals’ herself to herself through interaction with her supervisors. The supervisors are also ‘rewritten’ in their situated self-understanding during this process
Resilience of local communities to climate change around a ramsar site in Pakistan
The Taunsa Barrage controls water flow in the River Indus for irrigation and flood control purposes. The river ecology is sensitive to climate change due to the high portion of its flow derived glacial melt. To assess the socio-economic status of the rural communities living within the Taunsa Barrage Wildlife sanctuary, a questionnaire was developed based on the perception of local communities about their resilience capacity and climate change. Temperature and rainfall data over the period 1951 – 2010 were analysed and used as an indicator of climate change. 85 of the respondents (n =100) reported that there had been an increase extreme climatic events over the past 60 years. These communities have proved to be resilient (94% n = 100) to it by changing occupations and lifestyles. However at the same time they have increased the pressure on natural resource use and this is causing a serious problem in the management of the protected area
Modeling Enhancements in DSR, FSR, OLSR under Mobility and Scalability Constraints in VANETs
Frequent topological changes due to high mobility is one of the main issues
in Vehicular Ad-hoc NETworks (VANETs). In this paper, we model transmission
probabilities of 802.11p for VANETs and effect of these probabilities on
average transmission time. To evaluate the effect of these probabilities of
VANETs in routing protocols, we select Dynamic Source Routing (DSR), Fish-eye
State Routing (FSR) and Optimized Link State Routing (OLSR). Framework of these
protocols with respect to their packet cost is also presented in this work. A
novel contribution of this work is enhancement of chosen protocols to obtain
efficient behavior. Extensive simulation work is done to prove and compare the
efficiency in terms of high throughput of enhanced versions with default
versions of protocols in NS-2. For this comparison, we choose three performance
metrics; throughput, End-to-End Delay (E2ED) and Normalized Routing Load (NRL)
in different mobilities and scalabilities. Finally, we deduce that enhanced DSR
(DSR-mod) outperforms other protocols by achieving 16% more packet delivery for
all scalabilities and 28% more throughput in selected mobilities than original
version of DSR (DSR-orig)
Prospects for alleviating poverty and protecting the Taunsa barrage wildlife sanctuary, Indus river, Pakistan, through cultural and eco-tourism
The common assumption about protected areas is that they aggravate poverty amongst local residents by excluding them from livelihood activities such as fishing, agriculture, tourism and logging. It has been increasingly recognized that protected areas should instead contribute to sustaining the resident communities of surrounding areas. Eco-tourism could be an alternative form of income generation and has a substantial potential to boost and develop a relationship between people and nature. At the Taunsa Barrage Wildlife Sanctuary (TBWS), on the Indus River, Pakistan, local communities rely on local ecosystem services for up to 90% of their daily needs. To determine the potential for eco-tourism growth a SWOT analysis (Strengths, weaknesses, opportunities and threats) was designed based on discussion with stake holders (including community representative, non-governmental and governmental agencies)and personal observation during 2010. It is proposed as an approach for communities to utilize otherwise marginal cultural or ecological assets.Sustainability and involvement are both fundamental for the enduring future of this form of tourism. This study indicates that the prospects of eco-tourism as an instrument for empowerment and poverty alleviation at the TBWS are good.Eco-cultural tourism can offers ways to achieve sustainable resource and to engage with wider society. It could also act as a model for how cultural- and eco-tourism could empower local people in comparable settings in Pakistan
Elusive super-hard B6C accessible through the laser-floating zone method
Boron carbide is among the most promising ceramic materials nowadays: their mechanical properties are outstanding, and they open potential critical applications in near future. Since sinterability is the most critical drawback to this goal, innovative and competitive sintering procedures are attractive research topics in the science and technology of this carbide. This work reports the pioneer use of the laser-floating zone technique with this carbide. Crystallographic, microstructural and mechanical characterization of the so-prepared samples is carefully analysed. One unexpected output is the fabrication of a B6C composite when critical conditions of growth rate are adopted. Since this is one of the hardest materials in Nature and it is achievable only under extremely high pressures and temperatures in hot-pressing, the use of this technique offers a promising alternative for the fabrication. Hardness and elastic modulus of this material reached to 52¿GPa and 600¿GPa respectively, which is close to theoretical predictions reported in literature
PHYLLOIDES TUMOUR: REVIEW OF AN UNCOMMON BREAST PATHOLOGY AT A SPECIALIZED CANCER CENTRE
Purpose: Phyllodes tumours are rare breast tumours that comprise almost 1% of breast tumours. The outcome for these tumours is generally considered better than breast cancers. We review the cases of phyllodes tumour presenting to a specialised cancer centre over a 14 year period. Materials and Methods: All case records with the diagnosis of phyllodes tumour between 1999 and 2012 were retrieved from the cancer registry. Patient demographics, tumour site, size, axillary lymph node status, whether primary or recurrent, metastatic status, histological type, type of surgery, any complication, margin positivity, post-operative radiation therapy, local or distant recurrence, morality and follow-up duration were recorded. Data were analysed using SPSS. Results: A total of 77 cases of phyllodes tumour were seen between 1999 and 2012. All patients were female with a mean age of 39.9 years. All patients presented with a breast lump with median duration of 8 months. Almost two-thirds (65%) of the patients presented with primary tumour compared to 10% recurrent tumours and the rest were referred after surgery outside. Median size on histopathology was 5 cm (IQR 3.5–8.5 cm). Over a median follow-up duration of 31 months (IQR 9–48 months), 69 patients (89.6%) were alive, while 3 patients (3.9%) did not survive and 5 patients (6.4%) were lost to follow-up. Recurrence was seen in 10 (13%) patients with median time to recurrence of 12 months (IQR 7–24). Involved axillary lymph nodes and borderline or malignant histopathology were found to be signi cantly associated with recurrence (P = 0.04), while margin positivity, post operative radiation therapy and histopathology were not signi cantly associated with recurrence. Conclusion: Phyllodes tumour is an uncommon breast tumour that is predominantly treated with surgical excision. Although survival with these tumours is better compared to breast cancers, involvement of axillary nodes and borderline or malignant histopathology confer an increased risk of recurrence in these patients. Key words: Breast cancer, phyllodes tumours, survival
Studies on Staphylococcus aureus Isolated from Pimples
Background and Objective: Pimples (acne) are small skin lesions or inflammations of the skin. The most common factor causing acne is the hormonal changes that occur during adolescent and teenage years. Antibiotics are becoming less effective in the treatment of pimples due to increasing concerns of antibiotic resistance. This study was therefore carried out to characterize the isolates from the pimples of Covenant University Students and to determine their antibiotics sensitivity pattern. Materials and Methods: A total of 20 swab samples were obtained from male and female students with obvious signs of pimples in Covenant University, Ota, Ogun State, Nigeria. The samples obtained were cultured on Mannitol Salt Agar and incubated at 37EC. Pure isolates obtained were subjected to Gram staining and other biochemical tests for identification. The isolates were further subjected to antibiotics sensitivity tests using antibiotic dics. Results: Macroscopic examination indicated that the organisms were convex, smooth and shiny. Microscopic examination revealed that the isolates were positive after employing the Gram Staining technique and they appeared as grape-like clusters. Biochemical tests revealed that the isolates were Coagulase positive, Catalase positive, Urease positive, Citrate positive, Methyl-Red positive, Voges-Proskauer negative and negative upon starch hydrolysis. The sugar fermentation tests revealed that the isolates fermented Glucose, Maltose, Galactose, Sucrose and Lactose, respectively. The antibiotic susceptibility test showed that isolates were resistant to Cotrimazole, Cloxacillin, Erythromycin, Gentamycin, Augmentin, Streptomycin, Tetracycline and Chloramphenicol. Conclusion: The results therefore indicated that the isolates were Staphylococcus aureus and other staphylococci species. Indiscriminate use of antibiotics should be avoided to prevent the development of resistant strains of the Staphylococci genera and other pathogenic organisms
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