172 research outputs found

    Made in Oman: Promoting Manufacturing and Export in the Sultanate of Oman

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    Oman’s manufacturing sector has shown promising growth during the past decades. This paper analyzes the role of the manufacturing and export sector in economic growth and development. Then, after analyzing government policy toward manufacturing in Oman, this paper uses research gathered from companies in Rusayl to determine the biggest problems currently facing manufacturing in Oman and the effectiveness of government policy toward the sector. Problems found included excessive bureaucracy, Omanization, and transport costs. These findings were then presented to the appropriate public institutions, with their reactions documented. Recommendations for change include streamlining government services, expediting the construction of the Gulf Railway, and implementing an innovative credit-based solution to Omanization

    WO-Type Wolf-Rayet Stars: the Last Hurrah of Massive Star Evolution

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    Are WO-type Wolf Rayet (WR) stars in the final stage of massive star evolution before core-collapse? Although WC- and WO-type WRs have very similar spectra, WOs show a much stronger O VI λλ\lambda \lambda3811,34 emission-line feature. This has usually been interpreted to mean that WOs are more oxygen rich than WCs, and thus further evolved. However, previous studies have failed to model this line, leaving the relative abundances uncertain, and the relationship between the two types unresolved. To answer this fundamental question, we modeled six WCs and two WOs in the LMC using UV, optical, and NIR spectra with the radiative transfer code CMFGEN in order to determine their physical properties. We find that WOs are not richer in oxygen; rather, the O VI feature is insensitive to the abundance. However, the WOs have a significantly higher carbon and lower helium content than the WCs, and hence are further evolved. A comparison of our results with single-star Geneva and binary BPASS evolutionary models show that while many properties match, there is more carbon and less oxygen in the WOs than either set of evolutionary model predicts. This discrepancy may be due to the large uncertainty in the 12^{12}C+4^4He→16\rightarrow^{16}O nuclear reaction rate; we show that if the Kunz et al. rate is decreased by a factor of 25-50%, then there would be a good match with the observations. It would also help explain the LIGO/VIRGO detection of black holes whose masses are in the theoretical upper mass gap.Comment: 55 pages, 22 figures, Accepted into Ap

    Red Supergiants in the Andromeda Galaxy (M31)

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    Red supergiants are a short-lived stage in the evolution of moderately massive stars (10-25Mo), and as such their location in the H-R diagram provides an exacting test of stellar evolutionary models. Since massive star evolution is strongly affected by the amount of mass-loss a star suffers, and since the mass-loss rates depend upon metallicity, it is highly desirable to study the physical properties of these stars in galaxies of various metallicities. Here we identify a sample of red supergiants in M31 (the most metal-rich of the Local Group galaxies) and derive their physical properties by fitting MARCS atmosphere models to moderate resolution optical spectroscopy, and from V-K photometry.Comment: Accepted for publication in the Astrophysical Journa

    Effect of an Education Programme for South Asians with Asthma and Their Clinicians: A Cluster Randomised Controlled Trial (OEDIPUS).

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    BACKGROUND: People with asthma from ethnic minority groups experience significant morbidity. Culturally-specific interventions to reduce asthma morbidity are rare. We tested the hypothesis that a culturally-specific education programme, adapted from promising theory-based interventions developed in the USA, would reduce unscheduled care for South Asians with asthma in the UK. METHODS: A cluster randomised controlled trial, set in two east London boroughs. 105 of 107 eligible general practices were randomised to usual care or the education programme. Participants were south Asians with asthma aged 3 years and older with recent unscheduled care. The programme had two components: the Physician Asthma Care Education (PACE) programme and the Chronic Disease Self Management Programme (CDSMP), targeted at clinicians and patients with asthma respectively. Both were culturally adapted for south Asians with asthma. Specialist nurses, and primary care teams from intervention practices were trained using the PACE programme. South Asian participants attended an outpatient appointment; those registered with intervention practices received self-management training from PACE-trained specialist nurses, a follow-up appointment with PACE-trained primary care practices, and an invitation to attend the CDSMP. Patients from control practices received usual care. Primary outcome was unscheduled care. FINDINGS: 375 south Asians with asthma from 84 general practices took part, 183 registered with intervention practices and 192 with control practices. Primary outcome data were available for 358/375 (95.5%) of participants. The intervention had no effect on time to first unscheduled attendance for asthma (Adjusted Hazard Ratio AHR = 1.19 95% CI 0.92 to 1.53). Time to first review in primary care was reduced (AHR = 2.22, (1.67 to 2.95). Asthma-related quality of life and self-efficacy were improved at 3 months (adjusted mean difference -2.56, (-3.89 to -1.24); 0.44, (0.05 to 0.82) respectively. CONCLUSIONS: A multi-component education programme adapted for south Asians with asthma did not reduce unscheduled care but did improve follow-up in primary care, self-efficacy and quality of life. More effective interventions are needed for south Asians with asthma

    Resting pulmonary haemodynamics and shunting: a comparison of sea-level inhabitants to high altitude Sherpas

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    The incidence of blood flow through intracardiac shunt and intrapulmonary arteriovenous anastomoses (IPAVA) may differ between Sherpas permanently residing at high altitude (HA) and sea-level (SL) inhabitants as a result of evolutionary pressure to improve gas exchange and/or resting pulmonary haemodynamics. To test this hypothesis we compared sea-level inhabitants at SL (SL-SL; n = 17), during acute isocapnic hypoxia (SL-HX; n = 7) and following 3 weeks at 5050 m (SL-HA; n = 8 non-PFO subjects) to Sherpas at 5050 m (n = 14). inline image, heart rate, pulmonary artery systolic pressure (PASP) and cardiac index (Qi) were measured during 5 min of room air breathing at SL and HA, during 20 min of isocapnic hypoxia (SL-HX; inline image = 47 mmHg) and during 5 min of hyperoxia (inline image = 1.0; Sherpas only). Intracardiac shunt and IPAVA blood flow was evaluated by agitated saline contrast echocardiography. Although PASP was similar between groups at HA (Sherpas: 30.0 ± 6.0 mmHg; SL-HA: 32.7 ± 4.2 mmHg; P = 0.27), it was greater than SL-SL (19.4 ± 2.1 mmHg; P < 0.001). The proportion of subjects with intracardiac shunt was similar between groups (SL-SL: 41%; Sherpas: 50%). In the remaining subjects, IPAVA blood flow was found in 100% of subjects during acute isocapnic hypoxia at SL, but in only 4 of 7 Sherpas and 1 of 8 SL-HA subjects at rest. In conclusion, differences in resting pulmonary vascular regulation, intracardiac shunt and IPAVA blood flow do not appear to account for any adaptation to HA in Sherpas. Despite elevated pulmonary pressures and profound hypoxaemia, IPAVA blood flow in all subjects at HA was lower than expected compared to acute normobaric hypoxia

    Reduced blood flow through intrapulmonary arteriovenous anastomoses at rest and during exercise in lowlanders during acclimatization to high altitude

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    Blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA ) is elevated during exercise at sea level (SL) and at rest in acute normobaric hypoxia. Following high altitude (HA) acclimatization, resting QIPAVA is similar to SL, but it is unknown if this is true during exercise at HA. We reasoned that exercise at HA (5,050 m) would exacerbate QIPAVA due to heightened pulmonary arterial pressure. Using a supine cycle ergometer, seven healthy adults free from intracardiac shunts underwent an incremental exercise test at SL (25, 50, 75% of SL VO2peak ) and at HA (25, 50% of SL VO2peak ). Echocardiography was used to determine cardiac output (Q) and pulmonary artery systolic pressure (PASP) and agitated saline contrast was used to determine QIPAVA (bubble score; 0-5). The principal findings were: (1) Q was similar at SL-rest (3.9 +/- 0.47 l min-1 ) compared with HA-rest (4.5 +/- 0.49 l min-1 ; P = 0.382), but increased from rest during both SL and HA exercise (P < 0.001); (2) PASP increased from SL-rest (19.2 +/- 0.7 mmHg) to HA-rest (33.7 +/- 2.8 mmHg; P = 0.001) and, compared with SL, PASP was further elevated during HA exercise (P = 0.003); (3) QIPAVA was increased from SL-rest (0) to HA-rest (median = 1; P = 0.04) and increased from resting values during SL exercise (P < 0.05), but were unchanged during HA exercise (P = 0.91), despite significant increases in Q and PASP. Theoretical modeling of microbubble dissolution suggests that the lack of QIPAVA in response to exercise at HA is unlikely caused by saline contrast instability

    Tracking Changes in Bioavailable Fe Within High-Nitrate Low-Chlorophyll Oceanic Waters: A First Estimate Using a Heterotrophic Bacterial Bioreporter

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    It is conventional knowledge that heterotrophic bacteria play a key role in the biogeochemical cycling of oceanic carbon. However, only recently has their role in marine iron ( Fe) biogeochemical cycles been examined. Research during this past decade has demonstrated an inextricable link between Fe chemistry and the biota, as \u3e99% of Fe in marine systems is complexed to organic chelates of unknown but obviously biotic origin. Here we present a novel approach to assess and compare Fe bioavailability in low Fe HNLC waters using a bioluminescent bacterial reporter that quantitatively responds to the concentration of bioavailable Fe by producing light. Originally tested in freshwater environments, this study presents the first characterization of this halotolerant reporter organism in a defined seawater medium and then subsequently in marine surface waters. Laboratory characterizations demonstrate that this reporter displays a dose-dependent response to Fe availability in our defined marine medium. Field tests were performed during the 10-day mesoscale FeCycle experiment ( February 2003) in the Pacific sub-Antarctic high-nitrate low-chlorophyll region. Data from both biogeochemical measures and bioreporter assays are provided which describe how the bioreporter detected changes in Fe bioavailability that occurred during a natural shift in ambient dissolved Fe concentrations (similar to 40 pM). Our data explore the use of heterotrophic bioluminescent reporters as a comparable tool for marine ecosystems and demonstrate the potential utility of this tool in elucidating the relationship between Fe bioavailability and Fe chemistry in complex marine systems

    Hypoxia, not pulmonary vascular pressure induces blood flow through intrapulmonary arteriovenous anastomoses

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    Blood flow through intrapulmonary arteriovenous anastomoses (IPAVA) is increased with exposure to acute hypoxia and has been associated with pulmonary artery systolic pressure (PASP). We aimed to determine the direct relationship between blood flow through IPAVA and PASP in 10 participants with no detectable intracardiac shunt by comparing: (1) isocapnic hypoxia (control); (2) isocapnic hypoxia with oral administration of acetazolamide (AZ; 250 mg, three times-a-day for 48 h) to prevent increases in PASP, and (3) isocapnic hypoxia with AZ and 8.4% NaHCO3 infusion (AZ+HCO3-) to control for AZ-induced acidosis. Isocapnic hypoxia (20 min) was maintained by end-tidal forcing, blood flow through IPAVA was determined by agitated saline contrast echocardiography and PASP was estimated by Doppler ultrasound. Arterial blood samples were collected at rest before each isocapnic-hypoxia condition to determine pH, [HCO3-], and PaCO2. AZ decreased pH (-0.08 ± 0.01), [HCO3-] (-7.1 ± 0.7 mmol/l), and PaCO2 (-4.5 ± 1.4 mmHg; p<0.01), while intravenous NaHCO3 restored arterial blood gas parameters to control levels. Although PASP increased from baseline in all three hypoxic conditions (p<0.05), a main effect of condition expressed an 11 ± 2% reduction in PASP from control (p<0.001) following AZ administration while intravenous NaHCO3 partially restored the PASP response to isocapnic hypoxia. Blood flow through IPAVA increased during exposure to isocapnic hypoxia (p<0.01) and was unrelated to PASP, cardiac output and pulmonary vascular resistance for all conditions. In conclusion, isocapnic hypoxia induces blood flow through IPAVA independent of changes in PASP and the influence of AZ on the PASP response to isocapnic hypoxia is dependent upon the H+ concentration or PaCO2. Abbreviations list: AZ, acetazolamide; FEV1, forced expiratory volume in 1 second; FIO2, fraction of inspired oxygen; FVC, forced vital capacity; Hb, total haemoglobin; HPV, hypoxic pulmonary vasoconstriction; HR, heart rate; IPAVA, intrapulmonary arteriovenous anastomoses; MAP, mean arterial pressure; PASP, pulmonary artery systolic pressure; PETCO2, end-tidal partial pressure of carbon dioxide; PETO2, end-tidal partial pressure of oxygen; PFO, patent foramen ovale; PVR, pulmonary vascular resistance; Q̇c, cardiac output; RVOT, right ventricular outflow tract; SpO2, oxyhaemoglobin saturation; SV, stroke volume; TRV, tricuspid regurgitant velocity; V̇E, minute ventilation; VTI, velocity-time integra

    Anti-Bacterial Effects of Poly-N-Acetyl-Glucosamine Nanofibers in Cutaneous Wound Healing: Requirement for Akt1

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    Treatment of cutaneous wounds with poly-N-acetyl-glucosamine nanofibers (sNAG) results in increased kinetics of wound closure in diabetic animal models, which is due in part to increased expression of several cytokines, growth factors, and innate immune activation. Defensins are also important for wound healing and anti-microbial activities. Therefore, we tested whether sNAG nanofibers induce defensin expression resulting in bacterial clearance.The role of sNAG in defensin expression was examined using immunofluoresence microscopy, pharmacological inhibition, and shRNA knockdown in vitro. The ability of sNAG treatment to induce defensin expression and bacterial clearance in WT and AKT1-/- mice was carried out using immunofluoresent microscopy and tissue gram staining. Neutralization, using an antibody directed against β-defensin 3, was utilized to determine if the antimicrobial properties of sNAG are dependent on the induction of defensin expression.sNAG treatment causes increased expression of both α- and β-type defensins in endothelial cells and β-type defensins in keratinocytes. Pharmacological inhibition and shRNA knockdown implicates Akt1 in sNAG-dependent defensin expression in vitro, an activity also shown in an in vivo wound healing model. Importantly, sNAG treatment results in increased kinetics of wound closure in wild type animals. sNAG treatment decreases bacterial infection of cutaneous wounds infected with Staphylococcus aureus in wild type control animals but not in similarly treated Akt1 null animals. Furthermore, sNAG treatment of S. aureus infected wounds show an increased expression of β-defensin 3 which is required for sNAG-dependent bacterial clearance. Our findings suggest that Akt1 is involved in the regulation of defensin expression and the innate immune response important for bacterial clearance. Moreover, these findings support the use of sNAG nanofibers as a novel method for enhancing wound closure while simultaneously decreasing wound infection
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