692 research outputs found

    GaInNAs-based Hellish-vertical cavity semiconductor optical amplifier for 1.3 μm operation

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    Hot electron light emission and lasing in semiconductor heterostructure (Hellish) devices are surface emitters the operation of which is based on the longitudinal injection of electrons and holes in the active region. These devices can be designed to be used as vertical cavity surface emitting laser or, as in this study, as a vertical cavity semiconductor optical amplifier (VCSOA). This study investigates the prospects for a Hellish VCSOA based on GaInNAs/GaAs material for operation in the 1.3-μm wavelength range. Hellish VCSOAs have increased functionality, and use undoped distributed Bragg reflectors; and this coupled with direct injection into the active region is expected to yield improvements in the gain and bandwidth. The design of the Hellish VCSOA is based on the transfer matrix method and the optical field distribution within the structure, where the determination of the position of quantum wells is crucial. A full assessment of Hellish VCSOAs has been performed in a device with eleven layers of Ga0.35In0.65N0.02As0.08/GaAs quantum wells (QWs) in the active region. It was characterised through I-V, L-V and by spectral photoluminescence, electroluminescence and electro-photoluminescence as a function of temperature and applied bias. Cavity resonance and gain peak curves have been calculated at different temperatures. Good agreement between experimental and theoretical results has been obtained

    Abspaltung ortho-ständiger Substituenten aus ionisierten Phenyl-2-propanonen nach Elektronenstoßaktivierung

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    Die Molekülionen der Phenyl-2-propanone 2a-4a verlieren positionsspezifisch o-ständige Cl -, Br - bzw. I -Atome unter Bildung von (M-Hal')+- Ionen (m/z 133) hoher Intensität (70/12 eV; 1. und 2. FFR) und identischer Struktur (MIKE-CAD-Spektren). Die Fragmentionen bei m/z 133 aus o- Chlorphenyl-2-propanon (2a) und 2,2-Dimethyl-2,3-dihydro[fc]furan (11) sind von ähnlicher, aber nicht identischer Struktur. Die stoßaktivierten (2. FFR) (M-Br*)+-Ionen aus o-Bromphenyl-2-propanon (3a) und 1-Brom-lphenyl- 2-propanon (12) liefern praktisch deckungsgleiche Spektren. Die Hauptreaktion der (M-Hal')+-Ionen aus 2a-4a ist die Abspaltung von CO, das ausschließlich das C-Atom der Carbonylgruppe enthält (13C-Markierung). Der mechanistische Verlauf der Reaktionsfolge wird diskutiert (Abb. 5 und 8). In the gas phase, the phenyl-2-propanone molecules 2a-4a lose upon electron impact chloro-, bromo-, and iodo-radicals specifically at the orthoposition of the phenyl group giving rise to strong (M-Hal')+-ions (70/12 eV; 1st and 2nd FFR) of identical structure as confirmed by their MIKECAD- spectra. The daughter ions at m/z 133 from o-chlorophenyl-2-propanone (2a) and 2,2-dimethyl-2,3-dihydro[b]furane (11) are structurally similar but not identical (similarity index 99.8). The collisionally activated (2nd FFR) (M-Br')+-ions from o-bromophenyl-2-propanone (3a) and 1- bromo-1-phenyl-2-propanone (12) produce virtually congruent spectra. The most important subsequent fragmentation of the (M-Hal')+-ions from 2a-4a is the loss of CO which incorporates the C-atom of the carbonyl group exclusively (13C labelling). Mechanistic aspects of the fragmentation sequences are discussed (Figs. 5 and 8)

    Enhancement of Androgenesis and Plant Regeneration From Wheat Anther Culture by Seed Pre-Sowing Gamma Irradiation

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    Combination breeding and mutation breeding are widely used methods in plant breeding. Intensive studies are carried out on biotechnological methods that will allow obtaining homozygous lines in a short time in populations obtained with these two techniques. Numerous studies have been carried out by different researchers on mutation breeding in wheat. There are few studies on anther culture response in mutagen-treated genotypes. Two different bread wheat promising advanced lines were used as the material in the study, in which the possibilities of combining mutation breeding with anther culture through ionizing radiation in high quality wheat breeding were investigated. In the study, the responses of advanced bread wheat mutant lines to anther culture, to which eight different doses of gamma rays (0, 100, 150, 200, 250, 300, 350, 400 Gy) were applied, including the control, were investigated. There are significant differences between genotypes and irradiation doses for all traits studied. It has been shown that it is possible to decrease albinism and increase the response of anther culture with dose-dependent gamma irradiation depending on bread wheat varieties. In the multiple comparison test to classify the difference between doses; statistically, 150 gray dose 5.60 is in the first statistical class and in the first place with the number of transferred green plants. After that, it ranks second in the same class with the number of green plants transferred with a 300 gray dose of 5.21. In the total number of regenerated green plants excluding controls (888), 635 unit (71.5%) and 205 unit (23.1%) haploids and spontaneous double haploid plants were obtained, respectively. In the study integrated into the bread wheat breeding program, a total of 205 spontaneous double haploid mutant lines were produced. According to the data obtained, it was shown that the gamma ray doses of 150 and 200 Gy had a significant stimulation effect on all parameters studied and ultimately the success index of anther culture in bread wheat compared to control. © 2022 Namik Kemal University - Agricultural Faculty. All rights reserved

    Low efficacy of the combination artesunate plus amodiaquine for uncomplicated falciparum malaria among children under 5 years in Kailahun, Sierra Leone.

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    OBJECTIVE: In 2004, Sierra Leone adopted artesunate plus amodiaquine as first-line antimalarial treatment. We evaluated the efficacy of this combination in Kailahun, where a previous study had shown 70.2% efficacy of amodiaquine in monotherapy. METHODS: Method and outcome classification of the study complied with WHO guidelines. Children 6-59 months with uncomplicated malaria were followed-up for 28 days. PCR genotyping was used to distinguish recrudescence from reinfection. Reinfections were reclassified as cured. RESULTS: Of 172 children who were referred to the study clinic, 126 satisfied inclusion criteria and were enrolled. No early treatment failures were reported. The day 14, efficacy was 98.2% (95% CI: 93.8-99.8). Of 65 recurrent parasitaemias analysed by PCR, 17 were recrudescences. The PCR-adjusted day 28 efficacy was 84.5% (95% CI: 76.4-90.7). All true failures occurred in the last 8 days of follow-up. Of 110 children who completed the 28-day follow-up, 54 (49.1%) experienced a novel infection. CONCLUSION: The efficacy of this combination was disappointing. The high reinfection rate suggested little prophylactic effect. In Kailahun a more efficacious combination might be necessary in the future. The efficacy of AS + AQ needs to be monitored in Kailahun and in the other regions of Sierra Leone

    THE RELATIONSHIP BETWEEN TRUST, TURNOVER INTENTIONS AND EMOTIONS: AN APPLICATION

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    Managerial leaders and directors are required to succeed the method of “sense” and “emotion” very well, to achieve organizational aims (Lee, 2002). Organizations need to manage all the emotions and feelings and concepts that affect persons health and performance (Gross, 1999). Business life dealing with this issue has increased in seriousness because, the effect of emotions in decision making cleared with academic studies. There is a need to find the path to the correct leadership of emotions. Emotions in the organization help to identify thoughts about the presence and desire to work (Jackson, 2006). The main purpose of this study, which should be considered a descriptive survey in the general sense, is to investigate the relationship between emotional expressions, trust and turnover intentions. Two different surveys were used in order to measure and assess the emotions expressions, trust and turnover intentions. The survey conducted on 200 employees of the public sector institution. Data, obtained from questionnaires analyzed through the SPSS statistical packaged software. We found that especially trust factors (Trust in management, co-worker trust and trust to manager) had a significant effect on “satisfaction” factor of turnover intentions. In addition, we found that “Co-worker trust” had a negative and significant effect on “Seek for job” factor of turnover intentions

    Grain yield and some physiological traits associated with heat tolerance in bread wheat (Triticum aestivum L.) genotypes

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    This research was carried out in the experimental fields of Department of Field Crops, Faculty of Agriculture, the University of Namık Kemal in 2014-2015. In the study, totally 30 bread wheat (Triticum aestivum L.) genotypes (15 cultivars; early, medium-early and late-maturing 10 lines are tolerant to the heat-temperature stress which were provided by CIMMYT-International Maize and Wheat Improvement Center), 5 lines (were taken from the same university’s wheat breeding program which was collaborated by the CIMMYT) were used as an experimental material. The experiment was adjusted in a split-plot design with 3 replicates. Sowing dates (Normal (NS ? November 09, 2014) and Late sowing (LS ? January 09, 2015)) were constituted the main plots, and the genotypes constituted the sub-plots. These physiological traits ((membrane thermostability (MT), canopy temperature (CT), leaf chlorophyll content (LCC) and stomatal conductance (SC)) were measured at the LS stage due to giving much more correct, logical and meaningful results, but grain yield (GY) was fixed for all the sowing dates. Obtained findings are: The GY was varied between (4.35- 6.34 t ha-1) for genotypes; the MT was changed between (10.58-66.25%); the CT was realized between (17.67-22.00 oC); the LCC was varied between (38.30-53.30 SPAD) and the SC was changed between (25.20-166.80 mmol m-2 s-1). It was observed that most of the CIMMYT originated genotypes are tolerant to high-temperature stress and most of the wheats that are grown in Thrace Region are negatively affected by the high-temperature stress. © Ankara Üniversitesi Ziraat Fakültesi.AR.14.15This work was supported by the Office of Scientific Research Projects of Tekirda? Nam?k Kemal University (Project No. NKUBAP.00.24.AR.14.15).This work was supported by the Office of Scientific Research Projects of Tekirdağ Namık Kemal University (Project No. NKUBAP.00.24.AR.14.15)

    High carrier concentration induced effects on the bowing parameter and the temperature dependence of the band gap of Ga<sub>x</sub>In<sub>1−x</sub>N

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    The influence of intrinsic carrier concentration on the compositional and temperature dependence of the bandgap of GaxIn1-xN is investigated in nominally undoped samples with Ga fractions of x = 0.019, 0.062, 0.324, 0.52, and 0.56. Hall Effect results show that the free carrier density has a very weak temperature dependence and increases about a factor of 4, when the Ga composition increases from x = 0.019 to 0.56. The photoluminescence (PL) peak energy has also weak temperature dependence shifting to higher energies and the PL line shape becomes increasingly asymmetrical and broadens with increasing Ga composition. The observed characteristics of the PL spectra are explained in terms of the transitions from free electron to localized tail states and the high electron density induced many-body effects. The bowing parameter of GaxIn1-xN is obtained from the raw PL data as 2.5 eV. However, when the high carrier density induced effects are taken into account, it increases by about 14% to 2.9 eV. Furthermore, the temperature dependence of the PL peak becomes more pronounced and follows the expected temperature dependence of the bandgap variation

    Death rates from malaria epidemics, Burundi and Ethiopia.

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    Death rates exceeded emergency thresholds at 4 sites during epidemics of Plasmodium falciparum malaria in Burundi (2000-2001) and in Ethiopia (2003-2004). Deaths likely from malaria ranged from 1,000 to 8,900, depending on site, and accounted for 52% to 78% of total deaths. Earlier detection of malaria and better case management are needed

    Ascites as an initial presentation of spontaneously ruptured hydatid cyst

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    We describe the diagnosis of a 77-year-old woman admitted toour outpatient department with a 3-month history of abdominalbloating and distension. Abdominal computed tomographyrevealed a large cystic lesion in the posterior segment of the righthepatic lobe, with a separated germinal layer and widespreadascites with dense internal echoes and septal appearance. Theresult of a serum Echinococcus indirect haemagglutination testwas positive and findings were indicative of the spontaneousrupture of a hydatid cyst into the peritoneal cavity withouttrauma. Ascites is rarely seen in the course of hydatid disease,but can result from cyst rupture into the peritoneal cavity. Thisshould be considered in the differential diagnosis of ascites,especially in areas such as Turkey, where hydatid disease inendemic
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