Non-linear biases, stochastically-sampled effective Hamiltonians and spectral functions in quantum Monte Carlo methods

In this article we study examples of systematic biases that can occur in quantum Monte Carlo methods due to the accumulation of non-linear expectation values, and approaches by which these errors can be corrected. We begin with a study of the Krylov-projected FCIQMC (KP-FCIQMC) approach, which was recently introduced to allow efficient, stochastic calculation of dynamical properties. This requires the solution of a sampled effective Hamiltonian, resulting in a non-linear operation on these stochastic variables. We investigate the probability distribution of this eigenvalue problem to study both stochastic errors and systematic biases in the approach, and demonstrate that such errors can be significantly corrected by moving to a more appropriate basis. This is lastly expanded to include consideration of the correlation function QMC approach of Ceperley and Bernu, showing how such an approach can be taken in the FCIQMC framework.Comment: 12 pages, 7 figure

Improved sensitivity RF photonics doppler frequency measurement system

An improved sensitivity Doppler frequency measurement system based on microwave photonics technology was demonstrated practically. The system employs a four-wave mixing effect to achieve broad radio-frequency (RF) frequency measurement. In addition, a lock-in amplification technique was utilized to achieve high-measurement sensitivity. The system is, thus, capable of Doppler frequency estimation of radar echoes with a carrier frequency up to 40 GHz and a power level as low as $-$35 dBm. © 2009-2012 IEEE

Indoor Air Quality Forecast in Shared Spaces– Predictive Models and Adaptive Design Proposals

The high concentration of air pollutants in indoor environments can have a remarkable adverse impact on health and well-being, cognitive performance and productivity. Indoor air pollutants are especially problematic in naturally ventilated shared spaces such as classrooms and meeting rooms, where human-generated pollutants can rise rapidly. When the inhabitants are exposed to indoor air pollution, recovering from its ramifications takes time and harms their well-being in the long run. In our approach, we seek to predict and prevent such hazardous situations instead of rectifying them after they happen. The prediction and prevention are accomplished through algorithms that can learn from the evolution of air pollutants and other variables to indicate whether or not a high level of pollution is forecast. We present two AI-enabled methods, one providing the forecast for the concentration level of carbon dioxide in the next 5 and 20 minutes with 86% and 92% accuracy. The second algorithm provides predictive indicators about how the CO2 level will evolve during the upcoming session (meeting or a course) before the session starts. We will discuss design implications and present design proposals on how these methods can inform interactive solutions for preventing high concentrations of indoor air pollutants

Reasons for irregular use of ferrous sulfate tablet in women referred to health centers in Bourojen city, 2005-2006

چکیده: زمینه و هدف: خانم های باردار و شیرده از جمله گروههای در معرض خطر ‌کم خونی فقر آهن می باشند. با وجود برنامه مدون در ارتباط با مصرف قرص آهن توسط مادران، آمار به دست آمده نشان میدهد حدود 67 درصد زنان باردار و شیرده قرص آهن را صحیح و منظم مصرف نمی کنند. لذا این مطالعه با هدف بررسی علل مصرف نامنظم قرص آهن در خانم های باردار و شیرده مراجعه کننده به مراکز بهداشتی درمانی شهر بروجن انجام شد. روش بررسی:در این مطالعه توصیفی – تحلیلی که در مراکز بهداشتی درمانی شهر بروجن در سال 85-1384 انجام گرفت، 270 نفر خانم که در دوره 16 هفتگی حاملگی الی 2 ماهگی پس از زایمان قرار داشتند به روش دردسترس انتخاب و طی مصاحبه حضوری به سؤالات پرسشنامه حاوی اطلاعات دموگرافیک، چگونگی مصرف قرص آهن، نگرش و عملکرد مادران در این خصوص پاسخ دادند. از آزمونهای کای دو، من ویتنی و ویلکاکسون و کروسکال والیس جهت تجزیه و تحلیل آْماری اطلاعات استفاده شد. یافته ها: نتایج نشان داد که 1/33 مادران قرص آهن را مرتب و منظم مصرف می کردند، 8/56 نامنظم و 2/10 اصلا مصرف نمی‌کردند. بین مصرف نامنظم قرص آهن و سطح اقتصادی - اجتماعی خانواده و تعداد زایمان ارتبــاط معنی داری وجود نداشت. از علل مصرف نامنظم قرص آهن 4/48 مادران فراموش کردن وعده های مصرف دارو، 4/12 تهوع و استفراغ حاملگی و 4/16 عدم آگاهی نسبت به لزوم مصرف آهن را ذکر کردند. بین تعداد زایمان و یا حاملگی، سن فرد و شاغل بودن با آگاهی، نگرش و عملکرد آنان ارتباط معنی دار وجود نداشت (05/0

Neutrino spin oscillations in gravitational fields

We study neutrino spin oscillations in black hole backgrounds. In the case of a charged black hole, the maximum frequency of oscillations is a monotonically increasing function of the charge. For a rotating black hole, the maximum frequency decreases with increasing the angular momentum. In both cases, the frequency of spin oscillations decreases as the distance from the black hole grows. As a phenomenological application of our results, we study simple bipolar neutrino system which is an interesting example of collective neutrino oscillations. We show that the precession frequency of the flavor pendulum as a function of the neutrino number density will be higher for a charged/non-rotating black hole compared with a neutral/rotating black hole respectively.Comment: Replaced with the version accepted for publication in Gravitation and Cosmology, Springer. 10 pages. 4 figure

Semileptonic decays of baryons in a relativistic quark model

We calculate semileptonic decays of light and heavy baryons in a relativistically covariant constituent quark model. The model is based on the Bethe-Salpeter-equation in instantaneous approximation. It generates satisfactory mass spectra for mesons and baryons up to the highest observable energies. Without introducing additional free parameters we compute on this basis helicity amplitudes of electronic and muonic semileptonic decays of baryons. We thus obtain form factor ratios and decay rates in good agreement with experiment.Comment: 8 pages, 10 figures, 2 tables, typos remove

Nursing Students' Competencies in Evidence-Based Practice and Its Related Factors

Background: Evidence-Based Practice (EBP) is one of the nursing professional roles that can lead them to provide the best and more effective care. However, no studies are available on nursing students’ competencies in EBP. Objectives: This study aimed to investigate the nursing students’ knowledge, attitude and intention to implement EBP and its related factors in two nursing and midwifery faculties in Tehran, Iran. Materials and Methods: In this cross-sectional study, 170 undergraduate nursing students were selected from two faculties of nursing and midwifery in Tehran, Iran. A census sampling method was applied and they were all before graduation in 2013. The Rubin and Parrish questionnaire was used to assess the students’ knowledge, attitude and intention to implement EBP as well as factors affecting the implementation of EBP. Students completed the instrument through self-report. Descriptive statistics, Independent sample t-test and Pearson correlation coefficient were used to analyze the data. Results: The students mean scores of knowledge, attitude and intention to implement EBP was 31.08 ± 5.77, 50.40 ± 9.58, 36.01 ± 4.64, respectively. The students’ age was inversely correlated with their scores of knowledge, attitude and intention to use EBP (P < 0.05). However, the students’ GPA was in direct association with their knowledge, attitude and intention to implement EBP (P < 0.05). No significant differences were observed between the males and females mean scores in the three subscales. However, significant differences were found between the students mean scores in the two subscales of knowledge and attitudes toward EBP in terms of familiarity with statistics and research methods (P < 0.05). Neither familiarity with research methods nor familiarity with EBP could significantly affect the students’ intention to implement EBP. Conclusions: The present study showed that nursing students have not a high mean score in the three subscales of knowledge, attitude and intention to implement EBP. It is essential for faculties and nurse managers not only to focus on education of EBP, but also to support nurses and nursing students to implement it in the process patient care

Audit of Intrapartum Care Based on the National Guideline for Midwifery and Birth Services

© The Author(s) 2018. Providing high-quality maternity care is a worldwide health concern that necessitates regular assessment of intrapartum practice. In an observational study, we aimed to audit intrapartum care based on the National Guideline for Midwifery and Birth Services. Using quota sampling, a total of 200 pregnant women, admitted for normal vaginal delivery, were recruited from four educational hospitals in Tehran, Iran. An observational checklist was developed based on the national guideline to assess the quality of provided care. Content and face validity of the tool were checked and confirmed. Reliability of the observational checklist and questionnaire was confirmed using concurrent observation (intrarater reliability; r =.93) and test–retest (r =.9) methods, respectively. We found that the compatibility of intrapartum care and the national guideline in different domains were as follows: history taking 88.3%, vital sign measurement 64.6%, performing Leopold’s maneuver 38.5%, initial assessment 83.4%, labor care 22.5%, using pain relief methods 63.5%, labor progress assessment 71.5%, process of delivery 89.5%, and postpartum management 89.5%. The findings indicate that additional attention and monitoring are required to align current intrapartum care practices with the national guidelines