2,775 research outputs found

    Bottom-up Photonic Crystal Lasers

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    The directed growth of III–V nanopillars is used to demonstrate bottom-up photonic crystal lasers. Simultaneous formation of both the photonic band gap and active gain region is achieved via catalyst-free selective-area metal–organic chemical vapor deposition on masked GaAs substrates. The nanopillars implement a GaAs/InGaAs/GaAs axial double heterostructure for accurate, arbitrary placement of gain within the cavity and lateral InGaP shells to reduce surface recombination. The lasers operate single-mode at room temperature with low threshold peak power density of ~625 W/cm^2. Cavity resonance and lasing wavelength is lithographically defined by controlling pillar pitch and diameter to vary from 960 to 989 nm. We envision this bottom-up approach to pillar-based devices as a new platform for photonic systems integration

    The Gas Phase in a Low Metallicity ISM

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    Original article can be found at: http://journals.cambridge.org/ Copyright International Astronomical Union. DOI: 10.1017/S1743921308024927We present several results from our analysis of dwarf irregular galaxies culled from The HI Nearby Galaxy Survey (THINGS). We analyse the rotation curves of two galaxies based on “bulk” velocity fields, i.e. velocity maps from which random non–circular motions are removed. We confirm that their dark matter distribution is best fit by an isothermal halo model. We show that the star formation properties of dIrr galaxies resemble those of the outer parts of larger, spiral systems. Lastly, we study the large scale (3–D) distribution of the gas, and argue that the gas disk in dIrrs is thick, both in a relative, as well as in an absolute sense as compared to spirals. Massive star formation through subsequent supernova explosions is able to redistribute the bulk of the ISM, creating large cavities. These cavities are often larger, and longer–lived than in spiral galaxies.Peer reviewe

    Functional replacement of myostatin with GDF-11 in the germline of mice.

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    BACKGROUND: Myostatin (MSTN) is a transforming growth factor-ß superfamily member that acts as a major regulator of skeletal muscle mass. GDF-11, which is highly related to MSTN, plays multiple roles during embryonic development, including regulating development of the axial skeleton, kidneys, nervous system, and pancreas. As MSTN and GDF-11 share a high degree of amino acid sequence identity, behave virtually identically in cell culture assays, and utilize similar regulatory and signaling components, a critical question is whether their distinct biological functions result from inherent differences in their abilities to interact with specific regulatory and signaling components or whether their distinct biological functions mainly reflect their differing temporal and spatial patterns of expression. METHODS: We generated and characterized mice in which we precisely replaced in the germline the portion of the Mstn gene encoding the mature C-terminal peptide with the corresponding region of Gdf11. RESULTS: In mice homozygous for the knock-in allele, all of the circulating MSTN protein was replaced with GDF-11, resulting in ~ 30-40-fold increased levels of circulating GDF-11. Male mice homozygous for the knock-in allele had slightly decreased muscle weights, slightly increased weight gain in response to a high-fat diet, slightly increased plasma cholesterol and HDL levels, and significantly decreased bone density and bone mass, whereas female mice were mostly unaffected. CONCLUSIONS: GDF-11 appears to be capable of nearly completely functionally replacing MSTN in the control of muscle mass. The developmental and physiological consequences of replacing MSTN with GDF-11 are strikingly limited

    Analisis Pengaruh Promosi Terhadap Keputusan Pembelian pada Baby Shop di Surakarta

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    The purpose of this study was to examine the effect of Sales Promotion, Personal selling and advertising on purchasing decisions on ESBE Baby Shop consumers. This research method uses a quantitative approach that uses numerical data. The population of this study was 110 consumers. The sample used in this study were 100 consumers with a purposive sampling method. Data analysis techniques using are (1) instrument test (validity and reliability test), (2) Classical Assumption Test (normality, multicollinearity, heteroscedasticity) and (3) Hypothesis Test (multiple linear regression analysis, t test, F test and R2) . The results showed that the t test showed that (1) Sales Promotion had a significant effect on consumer purchasing decisions of Baby Shop ESBE. (2) Personal selling has a significant effect on purchasing decisions on ESBE Baby Shop consumers. (3) Advertising has a significant effect on purchasing decisions on ESBE Baby Shop consumers

    PENGARUH MOTIVASI DAN DISIPLIN KERJA TERHADAP KINERJA KARYAWAN PADA PT PLN (PERSERO) (Unit Induk Transmisi Jawa Bagian Tengah Unit Pelaksana Transmisi Cirebon)

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    ABSTRAK Penelitian ini berawal dari ditemukannya ada permasalahan pada kinerja karyawan. Masalah yang terlihat pada penelitian ini adalah kinerja karyawan yang rendah yang diakibatkan oleh motivasi dan disiplin kerja yang kurang optimal. Penelitian ini bertujuan untuk mengetahui seberapa besar pengaruh motivasi dan disiplin kerja terhadap kinerja karyawan di PT PLN (Persero) Unit Induk Trasmisi Jawa Bagian Tengah Unit Pelaksana Trasmisi Cirebon. Penelitian ini dilakukan dengan metode survei, data diperoleh dengan penyebaran kuesioner kepada 83 responden, yang menjadi populasi dalam penelitian ini adalah sebagian karyawan pada PT PLN (Persero) Unit Induk Trasmisi Jawa Bagian Tengah Unit Pelaksana Trasmisi Cirebon, sehingga dalam penelitian ini adalah metode sensus. Data dianalisis dengan menggunakan Analisis Regresi Linier berganda, analisis korelasi berganda dan analisis koefisien determinasi. Hasil penelitian secara deskriptif membuktikan bahwa, motivasi dan disiplin kerja berada pada kategori ‘cukup baik’, namun pencapaiannya belum optimal. Hasil penelitian secara verifikatif membuktikan bahwa terdapat pengaruh yang positif dan signifikan secara parsial maupun simultan baik secara langsung maupun tidak langsung dari motivasi dan disiplin kerja terhadap kinerja pegawai dimana yang paling dominan pengaruhnya adalah motivasi Kata kunci: Motivasi, Displin Kerja dan Kinerja Pegawa

    Development and initial validation of the bronchiectasis exacerbation and symptom tool (BEST)

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    BACKGROUND: Recurrent bronchiectasis exacerbations are related to deterioration of lung function, progression of the disease, impairment of quality of life, and to an increased mortality. Improved detection of exacerbations has been accomplished in chronic obstructive pulmonary disease through the use of patient completed diaries. These tools may enhance exacerbation reporting and identification. The aim of this study was to develop a novel symptom diary for bronchiectasis symptom burden and detection of exacerbations, named the BEST diary. METHODS: Prospective observational study of patients with bronchiectasis conducted at Ninewells Hospital, Dundee. We included patients with confirmed bronchiectasis by computed tomography, who were symptomatic and had at least 1 documented exacerbation of bronchiectasis in the previous 12\u2009months to participate. Symptoms were recorded daily in a diary incorporating cough, sputum volume, sputum colour, dyspnoea, fatigue and systemic disturbance scored from 0 to 26. RESULTS: Twenty-one patients were included in the study. We identified 29 reported (treated exacerbations) and 23 unreported (untreated) exacerbations over 6-month follow-up. The BEST diary score showed a good correlation with the established and validated questionnaires and measures of health status (COPD Assessment Test, r =\u20090.61, p =\u20090.0037, Leicester Cough Questionnaire, r =\u2009-\u20090.52,p =\u20090.0015, St Georges Respiratory Questionnaire, r =\u20090.61,p <\u20090.0001 and 6\u2009min walk test, r =\u2009-\u20090.46,p =\u20090.037). The mean BEST score at baseline was 7.1 points (SD 2.2). The peak symptom score during exacerbation was a mean of 16.4 (3.1), and the change from baseline to exacerbation was a mean of 9.1 points (SD 2.5). Mean duration of exacerbations based on time for a return to baseline symptoms was 15.3\u2009days (SD 5.7). A minimum clinically important difference of 4 points is proposed. CONCLUSIONS: The BEST symptom diary has shown concurrent validity with current health questionnaires and is responsive at onset and recovery from exacerbation. The BEST diary may be useful to detect and characterise exacerbations in bronchiectasis clinical trials

    ABO blood group system and placental malaria in an area of unstable malaria transmission in eastern Sudan

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    <p>Abstract</p> <p>Background</p> <p>Understanding the pathogenesis of malaria in pregnancy and its consequences for both the mother and the baby is fundamental for improving malaria control in pregnant women.</p> <p>Aim</p> <p>The study aimed to investigate the role of ABO blood groups on pregnancy outcomes in an area of unstable malaria transmission in eastern Sudan.</p> <p>Methods</p> <p>A total of 293 women delivering in New Half teaching hospital, eastern Sudan during the period October 2006–March 2007 have been analyzed. ABO blood groups were determined and placental histopathology examinations for malaria were performed. Birth and placental weight were recorded and maternal haemoglobin was measured.</p> <p>Results</p> <p>114 (39.7%), 61 (22.1%) and 118 (38.2%) women were primiparae, secundiparae and multiparae, respectively. The ABO blood group distribution was 82(A), 59 (B), 24 (AB) and 128 (O). Placental histopathology showed acute placental malaria infections in 6 (2%), chronic infections in 6 (2%), 82 (28.0%) of the placentae showed past infection and 199 (68.0%) showed no infection. There was no association between the age (OR = 1.02, 95% CI = 0.45–2.2; <it>P </it>= 0.9), parity (OR = 0.6, 95% CI = 0.3–1.2; <it>P </it>= 0.1) and placental malaria infections. In all parity blood group O was associated with a higher risk of past (OR = 1.9, 95% CI = 1.1–3.2; <it>P </it>= 0.01) placental malaria infection. This was also true when primiparae were considered separately (OR = 2.6, 95% CI = 1.05–6.5, <it>P </it>= 0.03).</p> <p>Among women with all placental infections/past placental infection, the mean haemoglobin was higher in women with the blood group O, but the mean birth weight, foeto-placental weight ratio was not different between these groups and the non-O group.</p> <p>Conclusion</p> <p>These results indicate that women of eastern Sudan are at risk for placental malaria infection irrespective to their age or parity. Those women with blood group O were at higher risk of past placental malaria infection.</p

    Local versus systemic control of bone and skeletal muscle mass by components of the transforming growth factor-β signaling pathway.

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    Skeletal muscle and bone homeostasis are regulated by members of the myostatin/GDF-11/activin branch of the transforming growth factor-β superfamily, which share many regulatory components, including inhibitory extracellular binding proteins and receptors that mediate signaling. Here, we present the results of genetic studies demonstrating a critical role for the binding protein follistatin (FST) in regulating both skeletal muscle and bone. Using an allelic series corresponding to varying expression levels of endogenous Fst, we show that FST acts in an exquisitely dose-dependent manner to regulate both muscle mass and bone density. Moreover, by employing a genetic strategy to target Fst expression only in the posterior (caudal) region of the animal, we show that the effects of Fst loss are mostly restricted to the posterior region, implying that locally produced FST plays a much more important role than circulating FST with respect to regulation of muscle and bone. Finally, we show that targeting receptors for these ligands specifically in osteoblasts leads to dramatic increases in bone mass, with trabecular bone volume fraction being increased by 12- to 13-fold and bone mineral density being increased by 8- to 9-fold in humeri, femurs, and lumbar vertebrae. These findings demonstrate that bone, like muscle, has an enormous inherent capacity for growth that is normally kept in check by this signaling system and suggest that the extent to which this regulatory mechanism may be used throughout the body to regulate tissue mass may be more significant than previously appreciated
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