210 research outputs found

    Digital frequency domain multiplexing readout electronics for the next generation of millimeter telescopes

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    Frequency domain multiplexing (fMux) is an established technique for the readout of transition-edge sensor (TES) bolometers in millimeter-wavelength astrophysical instrumentation. In fMux, the signals from multiple detectors are read out on a single pair of wires reducing the total cryogenic thermal loading as well as the cold component complexity and cost of a system. The current digital fMux system, in use by POLARBEAR, EBEX, and the South Pole Telescope, is limited to a multiplexing factor of 16 by the dynamic range of the Superconducting Quantum Interference Device pre-amplifier and the total system bandwidth. Increased multiplexing is key for the next generation of large format TES cameras, such as SPT-3G and POLARBEAR2, which plan to have on the of order 15,000 detectors. Here, we present the next generation fMux readout, focusing on the warm electronics. In this system, the multiplexing factor increases to 64 channels per module (2 wires) while maintaining low noise levels and detector stability. This is achieved by increasing the system bandwidth, reducing the dynamic range requirements though active feedback, and digital synthesis of voltage biases with a novel polyphase filter algorithm. In addition, a version of the new fMux readout includes features such as low power consumption and radiation-hard components making it viable for future space-based millimeter telescopes such as the LiteBIRD satellite.Comment: 15 pages, 10 figures. To be published in Proceedings of SPIE Volume 9153. Presented at SPIE Astronomical Telescopes + Instrumentation 2014, conference 915

    Evaluation of knowledge and practice behaviors of a group of Iranian obstetricians, general practitioners, and midwives, regarding periodontal disease and its effect on the pregnancy outcome

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    Background. Periodontal disease is considered as a risk factor for poor pregnancy outcomes, including preterm birth and low birth weight. Only few studies have assessed the knowledge and practice behaviours of healthcare providers, concerning oral health during pregnancy, periodontal diseases and their role in adverse pregnancy outcomes. The present study aimed to compare the knowledge and practice behaviours of a group of Iranian obstetricians, general practitioners, and midwives about periodontal disease.Design and methods. A cross-sectional study was conducted using a self-administered, structured questionnaire that was previously used in North Carolina. The questionnaire was translated into Persian language and was randomly distributed among 200 obstetricians, general practitioners, and midwives participating in an international congress. Data were analysed by Chi-square and spearman correlation tests using SPSS statistical software (version PASW 18).Results. A total of 150 completed the questionnaires, achieving a response rate of 75%. Totally, the knowledge of the obstetricians was more accurate compared to the two other groups and the midwives were the worst. More experienced general practitioners (P=0.002) and obstetricians (P=0.049) did less dental examinations for their patients during their first visit or periodically. More experienced obstetricians also referred their patients for dental examinations during pregnancy less than their less experienced colleagues (P<0.001).Conclusions. Although the participants had some knowledge about periodontal disease and its association with adverse pregnancy outcomes, there is much space for improvements. The participants’ attitude and knowledge were consistent

    Hypoglycemic Activity of Fumaria parviflora in Streptozotocin-Induced Diabetic Rats

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    Purpose: Fumaria parviflora Lam (Fumariaceae) has been used in traditional medicine in the treatment of several diseases such as diabetes. The present work was designed to evaluate the hypoglycaemic effects of methanolic extract (ME) of F. parviflora in normal and streptozotocin-induced diabetic rats. Methods: The rats used were allocated in six (I, II, III, IV, V and VI) experimental groups (n=5). Group I rats served as ‘normal control’ animals received distilled water and group II rats served as ‘diabetic control’ animals. Diabetes mellitus was induced in groups II, V and VI rats by intraperitoneal single injection of streptozotocin (STZ, 55 mg kg-1). Group V and VI rats were addi-tionally treated with ME (150 mg kg-1 day-1 and 250 mg kg-1 day-1, i.p. respectively) 24 hour post STZ injection, for seven consecutive days. Groups III and IV rats received only ME 150 mg kg-1 day-1 and 250 mg kg-1 day-1, i.p. respectively for seven days. The levels of blood glucose were determined using a Glucometer. Results: Administra-tion of F. parviflora extract showed a potent glucose lowering effect only on streptozo-tocin (STZ) induced diabetic rats below 100 mg/dl (P<0.001). However, no significant differences in the blood glucose levels were recorded between diabetic rats received 125 or 250 mg/kg of plant extracts. Conclusion: The findings of the study indicated that F. parviflora has significant hypoglycemic effect on STZ-induced diabetic rats with no effects on blood glucose levels of normal rats

    A hybrid unsupervised approach toward EEG epileptic spikes detection

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    Epileptic spikes are complementary sources of information in EEG to diagnose and localize the origin of epilepsy. However, not only is visual inspection of EEG labor intensive, time consuming, and prone to human error, but it also needs long-term training to acquire the level of skill required for identifying epileptic discharges. Therefore, computer-aided approaches were employed for the purpose of saving time and increasing the detection and source localization accuracy. One of the most important artifacts that may be confused as an epileptic spike, due to morphological resemblance, is eye blink. Only a few studies consider removal of this artifact prior to detection, and most of them used either visual inspection or computer-aided approaches, which need expert supervision. Consequently, in this paper, an unsupervised and EEG-based system with embedded eye blink artifact remover is developed to detect epileptic spikes. The proposed system includes three stages: eye blink artifact removal, feature extraction, and classification. Wavelet transform was employed for both artifact removal and feature extraction steps, and adaptive neuro-fuzzy inference system for classification purpose. The proposed method is verified using a publicly available EEG dataset. The results show the efficiency of this algorithm in detecting epileptic spikes using low-resolution EEG with least computational complexity, highest sensitivity, and lesser human interaction compared to similar studies. Moreover, since epileptic spike detection is a vital component of epilepsy source localization, therefore this algorithm can be utilized for EEG-based pre-surgical evaluation of epilepsy

    Proximity effect model for x-ray transition edge sensors

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    Transition Edge Sensors are ultra-sensitive superconducting detectors with applications in many areas of research, including astrophysics. The device consists of a superconducting thin film, often with additional normal metal features, held close to its transition temperature and connected to two superconducting leads of a higher transition temperature. There is currently no way to reliably assess the performance of a particular device geometry or material composition without making and testing the device. We have developed a proximity effect model based on the Usadel equations to predict the effects of device geometry and material composition on sensor performance. The model is successful in reproducing I-V curves for two devices currently under study. We use the model to suggest the optimal size and geometry for TESs, considering how small the devices can be made before their performance is compromised. In the future, device modelling prior to manufacture will reduce the need for time-consuming and expensive testing.This work was partly supported by ESA CTP contract with No. 4000114932/15/NL/BW and EU H2020 AHEAD program

    Comparative Study of the Hermeneutics of Mulla Sadra and Gadamer

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    Philosophical hermeneutics which means ontology of understanding delves into the ontological foundations of understanding and its existential conditions from philosophical perspective. Gadamer as a representative of this school of thought developed hermeneutics from the realm of methodology into ontology. The present study entitled “A Comparative Study of the Hermeneutics of Mulla Sadra and Gadamer” revealed that many hermeneutic features of Gadamer such as essence of understanding, ontology of text and interpreter, multiplicity of understandings, and the commentator’s presumptions are evident in the perception of Mulla Sadra from the Holy Quran. However, their hermeneutics are basically different in each of the above points. More importantly, Mulla Sadra believes that the Quran is determined by God so he does not believe in relativism which is the outcome of Gadamer’s hermeneutics. In fact, Mulla Sadra believes in the cautious integration of meaning horizon between the commentator and the text in accordance with the author’s will, so he regards accurate understanding of the texts achievable relying on the key role of the commentator on the one hand, and the author’s knowledge on the other hand

    Zimmermann-Laband syndrome : clinical and cytogenetic study in two related patients

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    Zimmermann?Laband Syndrome (ZLS) is an extremely rare autosomal dominant congenital disorder. It is a craniofacial malformation syndrome with predominant intraoral involvement consisting of gingival fibromatosis diffusion in early development. The molecular basis of ZLS is still unknown. Although familial aggregation with different inheritance patterns is detected in ZLS patients, most of the cases are sporadic. We report on two sibling patients with clinical manifestations of ZLS. Blood samples of both patients were obtained in EDTA-tubes followed by performing cytogenetic study using Cyto2.7M array. Analysis of the copy number was performed using the Chromosome Analysis Suite Software (version 1.0.1, annotation file na 30, Affymetrix) and interpreted with recourse to the UCSC genome browser (http://genome.ucsc.edu/; Human Mar. 2006NCBI Build 36.1/hg18 assembly). The array analysis revealed overlapping regions of chromosomal aberrations in both patients. We detected a 258-kb deletion at 3q13.13, a 89-kb duplication at 1q25.2 as well as two 67-kb duplications at 1p12 and 19q12. These altered regions do not contain any known genes and protein-coding sequences. In conclusion, the findings of this report revealed new chromosomal aberrations, including a deletion at 3q13.13 and duplications at 1q25.2, 1p12 and 19q12, in the two patients with ZLS. Such findings indicate that whole genome screening for genomic rearrangements is fruitful in typical and atypical patients with ZLS
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