632 research outputs found

    Possible evolution of dim radio quiet neutron star 1E 1207.4-5209 based on a B-decay model

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    Dim radio-quiet neutron star (DRQNS) 1E 1207.4-5209 is one of the most heavily examined isolated neutron stars. Wide absorption lines were observed in its spectrum obtained by both XMM-Newton and Chandra X-ray satellites. These absorption lines can be interpreted as a principal frequency centered at 0.7 keV and its harmonics at 1.4, 2.1 and possibly 2.8 keV. The principal line can be formed by resonant proton cyclotron scattering leading to a magnetic field which is two orders of magnitude larger than the perpendicular component of the surface dipole magnetic field (B) found from the rotation period (P) and the time rate of change in the rotation period (\.{P}) of 1E 1207.4-5209. Besides, age of the supernova remnant (SNR) G296.5+10.0 which is physically connected to 1E 1207.4-5209 is two orders of magnitude smaller than the characteristic age (τ\tau=P/2\.{P}) of the neutron star. These huge differences between the magnetic field values and the ages can be explained based on a B-decay model. If the decay is assumed to be exponential, the characteristic decay time turns out to be several thousand years which is three orders of magnitude smaller than the characteristic decay time of radio pulsars represented in an earlier work. The lack of detection of radio emission from DRQNSs and the lack of point sources and pulsar wind nebulae in most of the observed SNRs can also be partly explained by such a very rapid exponential decay. The large difference between the characteristic decay times of DRQNSs and radio pulsars must be related to the differences in the magnetic fields, equation of states and masses of these isolated neutron stars.Comment: 13 pages, 1 figur

    Sulfur-tolerant BaO/ZrO2/TiO2/Al2O3 quaternary mixed oxides for deNOX catalysis

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    Advanced quaternary mixed oxide materials in the form of BaO/Al2O3/ZrO2/TiO2 functionalized with Pt active sites (i.e. Pt/BaO/AZT) were synthesized and structurally characterized via XRD and BET in comparison to a conventional Pt/20BaO/Al benchmark NSR/LNT catalyst. The interactions of these catalysts' surfaces with SOx and NOx gases were monitored via in situ FTIR and TPD. There exists a delicate trade-off between NOx storage capacity (NSC) and sulfur uptake/poisoning which is strongly governed by the BaO loading/dispersion as well as the surface structure and acidity of the support material. Flow reactor measurements performed under realistic catalytic conditions show the high NOx activity for the Pt/20BaO/AZT catalyst at 573 K. After sulfur poisoning and subsequent regeneration at 773 and 973 K, Pt/20BaO/AZT surpassed the NOx catalytic performance at 573 K of all other investigated materials including the conventional Pt/20BaO/Al benchmark catalyst. � The Royal Society of Chemistry 2017

    ASSESSING THE IMPACT OF BEET WEBWORM MOTHS ON SUNFLOWER FIELDS USING MULTITEMPORAL SENTINEL-2 SATELLITE IMAGERY AND VEGETATION INDICES

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    Remote sensing technology plays a crucial role in detecting and monitoring environmental issues, offering the ability to monitor large areas, diagnose problems early, and facilitate accurate interventions. By integrating in-situ data with qualitative measurements obtained from satellite images, comprehensive insights can be obtained, and statistical inferences can be established. This study focuses on analyzing the damages caused by beet webworm moths (Loxostege sticticalis) in sunflower fields located in the Ortaca neighborhood of Tekirdağ province in Thrace region, utilizing Sentinel-2 satellite images and in-situ data collected from the sunflower fields in Ortaca. The relationship between different spectral indices, such as the Enhanced Vegetation Index, Chlorophyll Index Green, and spectral transformation techniques like Tasseled Cap Greenness, derived from Sentinel-2 satellite images, and the observed damage rates in various sunflower fields' in-situ data was investigated. The results revealed a negative correlation between the variables, highlighting EVI as the most effective indicator of damage among the plant indices. Leveraging these findings, a damage map was generated using EVI, enabling visual interpretation of the damage status in other sunflower fields within the study area. These findings offer valuable insights into the impact of pests on sunflower crops, despite the accuracy evaluation results falling below the desired level, with an overall accuracy of 75% and a Kappa accuracy of 65%, attributed to the limited availability of in-situ data

    Turner syndrome and associated problems in turkish children: A multicenter study

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    Objective: Turner syndrome (TS) is a chromosomal disorder caused by complete or partial X chromosome monosomy that manifests various clinical features depending on the karyotype and on the genetic background of affected girls. This study aimed to systematically investigate the key clinical features of TS in relationship to karyotype in a large pediatric Turkish patient population. Methods: Our retrospective study included 842 karyotype-proven TS patients aged 0-18 years who were evaluated in 35 different centers in Turkey in the years 2013-2014. Results: The most common karyotype was 45,X (50.7%), followed by 45,X/46,XX (10.8%), 46,X,i(Xq) (10.1%) and 45,X/46,X,i(Xq) (9.5%). Mean age at diagnosis was 10.2±4.4 years. The most common presenting complaints were short stature and delayed puberty. Among patients diagnosed before age one year, the ratio of karyotype 45,X was significantly higher than that of other karyotype groups. Cardiac defects (bicuspid aortic valve, coarctation of the aorta and aortic stenosi) were the most common congenital anomalies, occurring in 25% of the TS cases. This was followed by urinary system anomalies (horseshoe kidney, double collector duct system and renal rotation) detected in 16.3%. Hashimoto’s thyroiditis was found in 11.1% of patients, gastrointestinal abnormalities in 8.9%, ear nose and throat problems in 22.6%, dermatologic problems in 21.8% and osteoporosis in 15.3%. Learning difficulties and/or psychosocial problems were encountered in 39.1%. Insulin resistance and impaired fasting glucose were detected in 3.4% and 2.2%, respectively. Dyslipidemia prevalence was 11.4%. Conclusion: This comprehensive study systematically evaluated the largest group of karyotype-proven TS girls to date. The karyotype distribution, congenital anomaly and comorbidity profile closely parallel that from other countries and support the need for close medical surveillance of these complex patients throughout their lifespan. © Journal of Clinical Research in Pediatric Endocrinology

    Percutaneous septal ablation for left mid-ventricular obstructive hypertrophic cardiomyopathy: a case report

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    BACKGROUND: Mid-ventricular obstructive hypertrophic cardiomyopathy (MVOHC) is a rare type of cardiomyopathy. The diagnosis is based on the hourglass appearance on the left ventriculogram and the presence of pressure gradient between apical and basal chamber of the ventriculum on the hemodynamic assessment. CASE PRESENTATION: The present case represents successful percutaneous treatment with septal ablation to patient with MVOHC associated with systolic anterior motion of the mitral valve and obstruction at both the mid-ventricular and outflow levels. CONCLUSION: Alcohol septal ablation has been proposed as less invasive alternatives to surgery in patients with MVOHC

    Prevalence of Helicobacter pylori in Children and Their Family Members in a District in Turkey

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    The aim of this study was to determine the prevalence of Helicobacter pylori among children and their family members and to evaluate some epidemiologic characteristics. The study included 275 children, aged 1-15 year(s), suffering from different gastrointestinal complaints. Blood serology and stool antigen testing were used for the diagnosis of infection due to H. pylori. Sixty-five (23.6%) of the 275 children were positive for H. pylori, and thispositivity had a significantly increasing correlation with age (p<0.001). H. pylori-associated infection was observed among 45 (69.2%) and 17 (8%) mothers in the H. pylori-infected and non-infected groups respectively (p<0.0001). Most children and their families infected with H. pylori were living in an urban area. The findings suggest that infectiondue to H. pylori is a problem for this district area, and all children having any gastrointestinal complaints should be examined whether H. pylori was prevalent among their family members
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