544 research outputs found

    Parallel, linear-scaling building-block and embedding method based on localized orbitals and orbital-specific basis sets

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    We present a new linear scaling method for the energy minimization step of semiempirical and first-principles Hartree-Fock and Kohn-Sham calculations. It is based on the self-consistent calculation of the optimum localized orbitals of any localization method of choice and on the use of orbital-specific basis sets. The full set of localized orbitals of a large molecule is seen as an orbital mosaic where each tessera is made of only a few of them. The orbital tesserae are computed out of a set of embedded cluster pseudoeigenvalue coupled equations which are solved in a building-block self-consistent fashion. In each iteration, the embedded cluster equations are solved independently of each other and, as a result, the method is parallel at a high level of the calculation. In addition to full system calculations, the method enables to perform simpler, much less demanding embedded cluster calculations, where only a fraction of the localized molecular orbitals are variational while the rest are frozen, taking advantage of the transferability of the localized orbitals of a given localization method between similar molecules. Monitoring single point energy calculations of large poly(ethylene oxide) molecules and three dimensional carbon monoxide clusters using an extended Huckel Hamiltonian are presented.Comment: latex, 15 pages, 10 figures, accepted for publication in J.Chem.Phy

    Prehabilitation for Shoulder Dysfunction in Breast Cancer

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    Objective: To evaluate prehabilitation exercises to improve shoulder pain and abduction range of motion (ROM) after breast cancer surgery; to evaluate methods of exercise teaching; to assess postsurgical seroma formation. Design: Pilot study Setting: Academic medical center Participants: 60 breast cancer patients were randomly assigned to either personal exercise instruction, group 1, n=36, or video only instruction, group 2, n=24. Interventions: Shoulder exercises were assigned to both groups 1 month prior to surgery at an outpatient visit. Group 1 received personal instruction on exercises, plus written exercise instruction, and a link to access an online video. Group 2 received only written exercise instruction and a link to access the online video. Main Outcome Measures: Exercise compliance, pain (via visual analog scale), shoulder abduction ROM (via goniometer), and presence or absence of seroma. Results or Clinical Course: 76% of study patients chose to exercise. There was no difference in exercise compliance between personal instruction versus video teaching. (75%, 24/32 in-person vs. 77%, 10/13 video only, OR=1.03). 66% of patients (20/30) lost greater than 10 degrees shoulder abduction ROM at 1 month post surgery. 29% of patients (9/31) had worse shoulder pain at one month post surgery than at baseline (24%, 6/25 exercisers, and 50%, 3/6 non-exercisers). 15% of patients (4/27) had worse shoulder pain at 3 months post surgery than at baseline (8%, 2/25 exercisers, and 100%, 2/2 non-exercisers). Prehabilitation exercise program inferred no additional risk of seroma formation (21%, 7/33 exercisers vs. 22%, 2/9 non-exercisers OR=.94). Conclusion: In-person teaching does not appear superior to video teaching for prehabilitation exercises in breast cancer. A high quality randomized controlled trial is necessary to assess efficacy of prehabilitation for improving post surgical outcomes. Prehabilitation exercises do not appear to increase risk of seroma formation in breast cancer surgery

    Non-take-up of benefits at the start of the COVID-19 pandemic

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    In this report, we look at the number of people eligible for UC but who didn't claim it, why they didn't claim, and their situation (funded by the Health Foundation)

    Reading with drama: relations between texts, readers and experiences

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    This article explores the intersections of drama and reading, specifically focusing on approaches that are situated within “drama in education.” Supported with a retrospective analysis, this article portrays the research, related practice and possible futures in drama education in relation to literacy and in particular to reading fiction as meaning making practice. This study is situated in a reassertion of the value of relational literacies through imaginative practices that dramatic modes generate and support. The article disrupts common misconceptions about the purposes and effects of drama in reading and establishes prominent research discourses and definitions across the history of drama and reading practices. By locating paradigmatic and practical opportunities in our analysis of contemporary research, we bring visibility to the intricacies of drama in education as a generative pedagogy in reading as relational meaning making work

    Maximally-localized generalized Wannier functions for composite energy bands

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    We discuss a method for determining the optimally-localized set of generalized Wannier functions associated with a set of Bloch bands in a crystalline solid. By ``generalized Wannier functions'' we mean a set of localized orthonormal orbitals spanning the same space as the specified set of Bloch bands. Although we minimize a functional that represents the total spread sum_n [ _n - _n^2 ] of the Wannier functions in real space, our method proceeds directly from the Bloch functions as represented on a mesh of k-points, and carries out the minimization in a space of unitary matrices U_mn^k describing the rotation among the Bloch bands at each k-point. The method is thus suitable for use in connection with conventional electronic-structure codes. The procedure also returns the total electric polarization as well as the location of each Wannier center. Sample results for Si, GaAs, molecular C2H4, and LiCl will be presented.Comment: 22 pages, two-column style with 4 postscript figures embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#nm_wan

    The Effective Fragment Molecular Orbital Method for Fragments Connected by Covalent Bonds

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    We extend the effective fragment molecular orbital method (EFMO) into treating fragments connected by covalent bonds. The accuracy of EFMO is compared to FMO and conventional ab initio electronic structure methods for polypeptides including proteins. Errors in energy for RHF and MP2 are within 2 kcal/mol for neutral polypeptides and 6 kcal/mol for charged polypeptides similar to FMO but obtained two to five times faster. For proteins, the errors are also within a few kcal/mol of the FMO results. We developed both the RHF and MP2 gradient for EFMO. Compared to ab initio, the EFMO optimized structures had an RMSD of 0.40 and 0.44 {\AA} for RHF and MP2, respectively.Comment: Revised manuscrip

    Risk factors for breast cancer characterized by the estrogen receptor alpha A908G (K303R) mutation

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    Abstract Introduction Estrogen is important in the development of breast cancer, and its biological effects are mediated primarily through the two estrogen receptors alpha and beta. A point mutation in the estrogen receptor alpha gene, ESR1, referred to as A908G or K303R, was originally identified in breast hyperplasias and was reported to be hypersensitive to estrogen. We recently detected this mutation at a low frequency of 6% in invasive breast tumors of the Carolina Breast Cancer Study (CBCS). Methods In this report, we evaluated risk factors for invasive breast cancer classified according to the presence or absence of the ESR1 A908G mutation in the CBCS, a population-based case-control study of breast cancer among younger and older white and African-American women in North Carolina. Of the 653 breast tumors evaluated, 37 were ESR1 A908G mutation-positive and 616 were mutation-negative. Results ESR1 A908G mutation-positive breast cancer was significantly associated with a first-degree family history of breast cancer (odds ratio [OR] = 2.69, 95% confidence interval [CI] = 1.15 to 6.28), whereas mutation-negative breast cancer was not. Comparison of the two case subgroups supported this finding (OR = 2.65, 95% CI = 1.15 to 6.09). There was also the suggestion that longer duration of oral contraceptive (OC) use (OR = 3.73, 95% CI = 1.16 to 12.03; P trend = 0.02 for use of more than 10 years) and recent use of OCs (OR = 3.63, 95% CI = 0.80 to 16.45; P trend = 0.10 for use within 10 years) were associated with ESR1 A908G mutation-positive breast cancer; however, ORs for comparison of the two case subgroups were not statistically significant. Hormone replacement therapy use was inversely correlated with mutation-negative breast cancer, but the effect on mutation-positive cancer was unclear due to the small number of postmenopausal cases whose tumors carried the mutation. Mutation-negative breast cancer was associated with several reproductive factors, including younger age at menarche (OR = 1.46, 95% CI = 1.09 to 1.94) and greater total estimated years of ovarian function (OR = 1.82, 95% CI = 1.21 to 2.74). Conclusion These preliminary results suggest that OCs may interact with the ESR1 A908G mutant receptor to drive the development of some breast tumors

    Mobile laminar air flow screen for additional operating room ventilation: reduction of intraoperative bacterial contamination during total knee arthroplasty

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    Background Surgical site infections are important complications in orthopedic surgery. A mobile laminar air flow (LAF) screen could represent a useful addition to an operating room (OR) with conventional turbulent air ventilation (12.5 air changes/h), as it could decrease the bacterial count near the operating field. The purpose of this study was to evaluate LAF efficacy at reducing bacterial contamination in the surgical area during 34 total knee arthroplasties (TKAs). Materials and methods The additional unit was used in 17 operations; the LAF was positioned beside the operating table between two of the surgeons, with the air flow directed towards the surgical area (wound). The whole team wore conventional OR clothing and the correct hygiene procedures and rituals were used. Bacterial air contamination (CFU/m3) was evaluated in the wound area in 17 operations with the LAF unit and 17 without the LAF unit. Results The LAF unit reduced the mean bacterial count in the wound area from 23.5 CFU/m3 without the LAF to 3.5 CFU/m3 with the LAF (P<0.0001), which is below the suggested limit for anORwith ultraclean laminar ventilation. There were no significant differences in the mean bacterial count in the instrument table area: 28.6 CFU/m3 were recorded with the LAF (N = 6) unit and 30.8 CFU/m3 (N = 6) without the LAF unit (P = 0.631). During six operations with LAF and six without LAF, particle counts were performed and the number of 0.5 lm particles was analyzed. The particle counts decreased significantly when the LAF unit was used (P = 0.003). Conclusion When a mobile LAF unit was added to the standard OR ventilation, bacterial contamination of the wound area significantly decreased to below the accepted level for an ultraclean OR, preventing SSI infections

    At the edge of the safety net : unsuccessful benefits claims at the start of the COVID-19 pandemic - Welfare at a (Social) Distance Rapid Report #3

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    There has been much scrutiny of the British benefits system during COVID-19, and most experts agree that the benefits system has performed well, even if historic weaknesses remain. Yet little attention has been paid to those who start a claim that is ultimately not successful. This report focuses on these ‘unsuccessful claimants’, using new YouGov survey data and interviews funded by the Health Foundation. Unsuccessful claimants raise two policy issues. Firstly, some claims are unsuccessful because of problems with the process of claiming benefits. Did the changes made by the Department for Work and Pensions (DWP) in response to COVID-19 ensure that everyone could navigate the system? Secondly, some claims are unsuccessful because of the design of the benefits system: these people are not eligible for benefits. This reflects decisions by policymakers about the purpose of a policy and how this can best be achieved, balanced against wider impacts including poverty, health and wellbeing; the public finances; and the wider economy
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