807 research outputs found

    Classical kinetic energy, quantum fluctuation terms and kinetic-energy functionals

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    We employ a recently formulated dequantization procedure to obtain an exact expression for the kinetic energy which is applicable to all kinetic-energy functionals. We express the kinetic energy of an N-electron system as the sum of an N-electron classical kinetic energy and an N-electron purely quantum kinetic energy arising from the quantum fluctuations that turn the classical momentum into the quantum momentum. This leads to an interesting analogy with Nelson's stochastic approach to quantum mechanics, which we use to conceptually clarify the physical nature of part of the kinetic-energy functional in terms of statistical fluctuations and in direct correspondence with Fisher Information Theory. We show that the N-electron purely quantum kinetic energy can be written as the sum of the (one-electron) Weizsacker term and an (N-1)-electron kinetic correlation term. We further show that the Weizsacker term results from local fluctuations while the kinetic correlation term results from the nonlocal fluctuations. For one-electron orbitals (where kinetic correlation is neglected) we obtain an exact (albeit impractical) expression for the noninteracting kinetic energy as the sum of the classical kinetic energy and the Weizsacker term. The classical kinetic energy is seen to be explicitly dependent on the electron phase and this has implications for the development of accurate orbital-free kinetic-energy functionals. Also, there is a direct connection between the classical kinetic energy and the angular momentum and, across a row of the periodic table, the classical kinetic energy component of the noninteracting kinetic energy generally increases as Z increases.Comment: 10 pages, 1 figure. To appear in Theor Chem Ac

    Patient-reported outcome after rheumatoid arthritis-related surgery in the lower extremities: A report from the Swedish National Register of Rheuma Surgery (RAKIR)

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    Background and purpose Although decreasing with the development of effective pharmacological regimes, joint surgery has improved the function and quality of life of patients with rheumatoid arthritis (RA). Few studies have assessed patient-reported outcomes after RA surgery to the lower extremities. Here we report patient-relevant outcome after RA-related surgery based on the first data from the Swedish National Register of Rheuma Surgery (RAKIR). Patients and methods 258 RA patients (212 women) who had joint surgery performed at the Department of Orthopaedics, Spenshult Hospital between September 2007 and June 2009 were included. Mean age at surgery was 64 (20-86) years. The patients completed the SF-36 and HAQ questionnaires preoperatively and 6 months postoperatively, and 165 patients completed them after 12 months. Results Improvement was seen as early as at 6 months. At 12 months, 165 patients (141 women)-including hip (n = 15), knee (n = 27), foot (n = 102), and ankle (n = 21) patients-reported statistically significant improvements from preoperatively to 12 months postoperatively in HAQ (mean change: -0.11) and SF-36 subscales physical function (11), role physical (12), bodily pain (13), social functioning (6.4), and role emotional (9.4). Hip and knee patients reported the greatest improvements. Interpretation Orthopedic RA-related surgery of the lower extremities has a strong effect on pain and physical function. Improvement is evident as early as 6 months postoperatively and remains after 12 months

    No evidence for selective follicle abortion underlying primary sex ratio adjustment in pigeons

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    Primary sex ratio adjustment in birds has been extensively studied, yet the underlying physiological mechanisms are far from understood. Avian females are the heterogametic sex (ZW), and the future sex of the offspring is determined at chromosome segregation during meiosis I, shortly before the oocyte is ovulated. Assuming that the mother can detect the sex of the developing oocyte before ovulation, it has been suggested that a follicle of the un-preferred sex could selectively be induced to become atretic and regress instead of being ovulated (selective follicle abortion). This potential mechanism has been proposed to underlie biased primary sex ratios in birds, including the homing pigeon (Columba livia domestica), which produces a modal clutch size of two eggs. However, without replacement by an additional, already mature follicle, abortion of a preovulatory follicle would most likely result in either reduced clutch sizes or laying gaps, since a not-yet-recruited follicle still needed to undergo the whole maturation phase. In the current study we killed female pigeons, which were adjusting embryo sex of first eggs according to change in body mass. We examined ovaries for signs of follicle abortion but did not find any supporting evidence. All females produced one or two mature follicles but only two out of the 56 experimental birds produced an additional third mature follicle. Therefore, our results do not corroborate the hypothesis that pigeon mothers manipulate primary offspring sex by selectively aborting follicles of the un-preferred sex

    Search for CP violation in D+→ϕπ+ and D+s→K0Sπ+ decays

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    A search for CP violation in D + → ϕπ + decays is performed using data collected in 2011 by the LHCb experiment corresponding to an integrated luminosity of 1.0 fb−1 at a centre of mass energy of 7 TeV. The CP -violating asymmetry is measured to be (−0.04 ± 0.14 ± 0.14)% for candidates with K − K + mass within 20 MeV/c 2 of the ϕ meson mass. A search for a CP -violating asymmetry that varies across the ϕ mass region of the D + → K − K + π + Dalitz plot is also performed, and no evidence for CP violation is found. In addition, the CP asymmetry in the D+s→K0Sπ+ decay is measured to be (0.61 ± 0.83 ± 0.14)%

    Are Child and Adolescent Responses to Placebo Higher in Major Depression than in Anxiety Disorders? A Systematic Review of Placebo-Controlled Trials

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    BACKGROUND: In a previous report, we hypothesized that responses to placebo were high in child and adolescent depression because of specific psychopathological factors associated with youth major depression. The purpose of this study was to compare the placebo response rates in pharmacological trials for major depressive disorder (MDD), obsessive compulsive disorder (OCD) and other anxiety disorders (AD-non-OCD). METHODOLOGY AND PRINCIPAL FINDINGS: We reviewed the literature relevant to the use of psychotropic medication in children and adolescents with internalized disorders, restricting our review to double-blind studies including a placebo arm. Placebo response rates were pooled and compared according to diagnosis (MDD vs. OCD vs. AD-non-OCD), age (adolescent vs. child), and date of publication. From 1972 to 2007, we found 23 trials that evaluated the efficacy of psychotropic medication (mainly non-tricyclic antidepressants) involving youth with MDD, 7 pertaining to youth with OCD, and 10 pertaining to youth with other anxiety disorders (N = 2533 patients in placebo arms). As hypothesized, the placebo response rate was significantly higher in studies on MDD, than in those examining OCD and AD-non-OCD (49.6% [range: 17-90%] vs. 31% [range: 4-41%] vs. 39.6% [range: 9-53], respectively, ANOVA F = 7.1, p = 0.002). Children showed a higher stable placebo response within all three diagnoses than adolescents, though this difference was not significant. Finally, no significant effects were found with respect to the year of publication. CONCLUSION: MDD in children and adolescents appears to be more responsive to placebo than other internalized conditions, which highlights differential psychopathology

    Clinical predictors of elective total joint replacement in persons with end-stage knee osteoarthritis

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    Abstract Background Arthritis is a leading cause of disability in the United States. Total knee arthroplasty (TKA) has become the gold standard to manage the pain and disability associated with knee osteoarthritis (OA). Although more than 400 000 primary TKA surgeries are performed each year in the United States, not all individuals with knee OA elect to undergo the procedure. No clear consensus exists on criteria to determine who should undergo TKA. The purpose of this study was to determine which clinical factors will predict the decision to undergo TKA in individuals with end-stage knee OA. Knowledge of these factors will aid in clinical decision making for the timing of TKA. Methods Functional data from one hundred twenty persons with end-stage knee OA were obtained through a database. All of the individuals complained of knee pain during daily activities and had radiographic evidence of OA. Functional and clinical tests, collectively referred to as the Delaware Osteoarthritis Profile, were completed by a physical therapist. This profile consisted of measuring height, weight, quadriceps strength and active knee range of motion, while functional mobility was assessed using the Timed Up and Go (TUG) test and the Stair Climbing Task (SCT). Self-perceived functional ability was measured using the activities of daily living subscale of the Knee Outcome Survey (KOS-ADLS). A logistic regression model was used to identify variables predictive of TKA use. Results Forty subjects (33%) underwent TKA within two years of evaluation. These subjects were significantly older and had significantly slower TUG and SCT times (p 2 = 0.403). Conclusions Younger patients with full knee ROM who have a higher self-perception of function are less likely to undergo TKA. Physicians and clinicians should be aware that potentially modifiable factors, such as knee ROM can be addressed to potentially postpone the need for TKA.</p

    Autism and ADHD Symptoms in Patients with OCD: Are They Associated with Specific OC Symptom Dimensions or OC Symptom Severity?

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    In obsessive-compulsive disorder (OCD), the relationship between autism spectrum disorders (ASD), attention-deficit/hyperactivity disorder (ADHD) symptom, and obsessive-compulsive (OC) symptom dimensions and severity has scarcely been studied. Therefore, 109 adult outpatients with primary OCD were compared to 87 healthy controls on OC, ADHD and ASD symptoms. OCD patients showed increased ADHD and autism symptom frequencies, OCD + ADHD patients reporting more autism symptoms (particularly attention switching and social skills problems) than OCD − ADHD patients. Attention switching problems were most significant predictors of OC symptom dimensions (except hoarding) and of symptom severity. Hoarding was not associated with elevated autism scale scores, but with inattention. In conclusion, attention switching problems may reflect both symptom overlap and a common etiological factor underlying ASD, ADHD and OCD

    The power of civilizational nationalism in Russian foreign policy making

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    The article draws upon theories of identity to understand Russian foreign policy towards Ukraine since 2000. The article argues that contemporary Russian foreign policy can be best understood as an articulation of ‘civilizational nationalism’ which relies on the myth of cultural superiority. The focus is on not only treating Russia as an imperial power, but on the cultural claims that this relies upon and its configuration within changing historical ideas of ‘Russianness’. Since the Orange Revolution, Russian presidents have accused Ukraine of following anti-Russian policies. This has been aided by a discourse of ‘civilizational nationalism’ where Ukraine is described as being part of a ‘Greater Russia’, rather than as a sovereign territory. This article analyses how imagined civilization and greatness of Russian culture is driving foreign policy making towards the Ukraine. Rather than an external territory, Ukraine is constructed as a ‘little brother’ which renders interventions legitimate
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