2,167 research outputs found

    Quantum Tunneling of the Magnetic Moment in a Free Particle

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    We study tunneling of the magnetic moment in a particle that has full rotational freedom. Exact energy levels are obtained and the ground-state magnetic moment is computed for a symmetric rotor. The effect of the mechanical freedom on spin tunneling manifests itself in a strong dependence of the magnetic moment on the moments of inertia of the rotor. Energy of the particle exhibits quantum phase transitions between states with different values of the magnetic moment. Particles of various shapes are investigated and quantum phase diagram is obtained.Comment: 7 Figures, 5 Figure Captions, submitted to PR

    Conservation of Angular Momentum in a Flux Qubit

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    Oscillations of superconducting current between clockwise and counterclockwise directions in a flux qubit do not conserve the angular momentum of the qubit. To compensate for this effect the solid containing the qubit must oscillate in unison with the current. This requires entanglement of quantum states of the qubit with quantum states of a macroscopic body. The question then arises whether slow decoherence of quantum oscillations of the current is consistent with fast decoherence of quantum states of a macroscopic solid. This problem is analyzed within an exactly solvable quantum model of a qubit embedded in an absolutely rigid solid and for the elastic model that conserves the total angular momentum. We show that while the quantum state of a flux qubit is, in general, a mixture of a large number of rotational states, slow decoherence is permitted if the system is macroscopically large. Practical implications of entanglement of qubit states with mechanical rotations are discussed.Comment: 10 page

    Investigating the removal of some pharmaceutical compounds in hospital wastewater treatment plants operating in Saudi Arabia

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    The concentrations of 12 pharmaceutical compounds (atenolol, erythromycin, cyclophosphamide, paracetamol, bezafibrate, carbamazepine, ciprofloxacin, caffeine, clarithromycin, lidocaine, sulfamethoxazole and Nacetylsulfamethoxazol (NACS)) were investigated in the influents and effluents of two hospital wastewater treatment plants (HWWTPs) in Saudi Arabia. The majority of the target analytes were detected in the influent samples apart from bezafibrate, cyclophosphamide, and erythromycin. Caffeine and paracetamol were detected in the influent at particularly high concentrations up to 75 and 12 ug/L, respectively. High removal efficiencies of the pharmaceutical compounds were observed in both HWWTPs, with greater than 90 % removal on average. Paracetamol, sulfamethoxazole, NACS, ciprofloxacin, and caffeine were eliminated by between >95 and >99 % on average. Atenolol, carbamazepine, and clarithromycin were eliminated by >86 % on average. Of particular interest were the high removal efficiencies of carbamazepine and antibiotics that were achieved by the HWWTPs; these compounds have been reported to be relatively recalcitrant to biological treatment and are generally only partially removed. Elevated temperatures and high levels of sunlight were considered to be the main factors that enhanced the removal of these compounds

    Network topology approach to new allotropes of the group 14 elements

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    The network topology approach has been a major driving force in the search for new metal-organic frameworks and coordination networks. In this work we demonstrate how this method not only generated the recently described "T12" allotrope of the group 14 elements, identical to the cdp topology found in the structure of CdP2, but also a number of other candidate structures for polymorphs of these network-forming elements. Data on such network structures have been compiled since the 1950's and is readily accessible through several internet based systems. The usefulness of topology for the classification of these allotropes is emphasised

    Evaluation of the orthodontic component of the hypodontia care pathway

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    INTRODUCTION: This study evaluated patients’ experiences of the Hypodontia Care Pathway at a large teaching hospital at key stages: specifically patient expectations/experience following the diagnosis of hypodontia and then patient satisfaction with the orthodontic care received and the outcome at the end of active orthodontic treatment. METHODOLOGY: In-depth, semi-structured interviews were conducted with twenty hypodontia patients following completion of orthodontic treatment but prior to any planned prosthodontic treatment commencing. Interviews were analysed qualitatively, using a framework approach. RESULTS: The framework analysis identified four main themes: perceptions of treatment, impact of the original malocclusion and the treatment process, the care team and communication. The themes were then further divided into subthemes. DISCUSSION: There was a large amount of positive feedback and the importance of the patient-clinician relationship was evident throughout. Where negative feedback was provided it mainly related to communication and areas were identified where change could take place in the future. CONCLUSIONS: Positive feedback was received and the importance of patient-clinician rapport was highlighted in all interviews. The main areas for improvement related to the importance of ensuring optimum communication, particularly with a cohort of patients who are often undergoing complex multidisciplinary treatment. Recommendations for the service have been made

    Penning ionization of doped helium nanodroplets following EUV excitation

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    Helium nanodroplets are widely used as a cold, weakly interacting matrix for spectroscopy of embedded species. In this work we excite or ionize doped He droplets using synchrotron radiation and study the effect onto the dopant atoms depending on their location inside the droplets (rare gases) or outside at the droplet surface (alkali metals). Using photoelectron-photoion coincidence imaging spectroscopy at variable photon energies (20-25 eV), we compare the rates of charge-transfer to Penning ionization of the dopants in the two cases. The surprising finding is that alkali metals, in contrast to the rare gases, are efficiently Penning ionized upon excitation of the (n=2)-bands of the host droplets. This indicates rapid migration of the excitation to the droplet surface, followed by relaxation, and eventually energy transfer to the alkali dopants

    A preliminary investigation into the endoparasite load of the European hedgehog (Erinaceus europaeus) in Ireland

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    The European hedgehog is strictly protected in the Republic of Ireland but has been little studied. Carcasses, such as road kill casualties, can provide valuable information on population demographics, parasite load and general body condition. This study aimed to examine the species of endoparasites present in hedgehogs, their prevalence and intensities and whether differences occurred depending on the age and sex of the hedgehog. Carcasses were collected and examined from around Ireland, over a 3-year period. In 21 of the 23 hedgehogs examined, endoparasites were identified. The nematode species, Crenosoma triatum and Capillaria erinacei were both positively identified. C. striatium was confined to the lungs, whereas C. erinacei was the most prevalent (87%) endoparasite and occurred in the stomach and intestines. There was a significantly higher load of Crenosoma striatum observed in male hedgehogs compared to females, but no significant difference was observed in the intensity of C. erinacei between the sexes. In all tissues, a greater mean endoparasite load was observed in male hedgehogs. Sex differences in exposure or immunity to parasitism could be related to the males’ larger home range and the effects of oestrogen levels on immunity

    Inhibition of miR-181a promotes midbrain neuronal growth through a Smad1/5-dependent mechanism: implications for Parkinson’s disease

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    Parkinson’s disease (PD) is the second most common neurodegenerative disease, and is characterized by the progressive degeneration of nigrostriatal dopaminergic (DA) neurons. Current PD treatments are symptomatic, wear off over time and do not protect against DA neuronal loss. Finding a way to re-grow midbrain DA (mDA) neurons is a promising disease-modifying therapeutic strategy for PD. However, reliable biomarkers are required to allow such growth-promoting approaches to be applied early in the disease progression. miR-181a has been shown to be dysregulated in PD patients, and has been identified as a potential biomarker for PD. Despite studies demonstrating the enrichment of miR-181a in the brain, specifically in neurites of postmitotic neurons, the role of miR-181a in mDA neurons remains unknown. Herein, we used cell culture models of human mDA neurons to investigate a potential role for miR-181a in mDA neurons. We used a bioninformatics analysis to identify that miR-181a targets components of the bone morphogenetic protein (BMP) signalling pathway, including the transcription factors Smad1 and Smad5, which we find are expressed by rat mDA neurons and are required for BMP-induced neurite growth. We also found that inhibition of neuronal miR-181a, resulted in increased Smad signalling, and induced neurite growth in SH-SY5Y cells. Finally, using embryonic rat cultures, we demonstrated that miR-181a inhibition induces ventral midbrain (VM) and cortical neuronal growth. These data describe a new role for miR-181a in mDA neurons, and provide proof of principle that miR-181a dysresgulation in PD may alter the activation state of signalling pathways important for neuronal growth in neurons affected in PD

    The clinical and cost-effectiveness of a Victim Improvement Package (VIP) for the reduction of chronic symptoms of depression or anxiety in older victims of common crime (the VIP trial): study protocol for a randomised controlled trial.

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    BACKGROUND: Older people are vulnerable to sustained high levels of psychosocial distress following a crime. A cognitive behavioural therapy (CBT)-informed psychological therapy, the Victim Improvement Package (VIP) may aid recovery. The VIP trial aims to test the clinical and cost-effectiveness of the VIP for alleviating depressive and anxiety symptoms in older victims of crime. METHODS/DESIGN: People aged 65 years or more who report being a victim of crime will be screened by Metropolitan Police Service Safer Neighbourhood Teams within a month of the crime for distress using the Patient Health Questionnaire-2 and the Generalised Anxiety Disorder-2. Those who screen positive will be signposted to their GP for assistance, and re-screened at 3 months. Participants who screen positive for depression and/or anxiety at re-screening are randomised to a CBT informed VIP added to treatment as usual (TAU) compared to TAU alone. The intervention consists of 10 individual 1-h sessions, delivered weekly by therapists from the mental health charity Mind. The primary outcome measure is the Beck Depression Inventory-II (BDI-II) and the Beck Anxiety Inventory (BAI), used as a composite measure, assessed at 6 months after the crime (post therapy) with a 9-month post-crime follow-up. Secondary outcome measures include the EQ-5D, and a modified Client Service Receipt Inventory. A total of 226 participants will be randomised VIP:TAU with a ratio 1:1, in order to detect a standardised difference of at least 0.5 between groups, using a mixed-effects linear-regression model with 90% power and a 5% significance level (adjusting for therapist clustering and potential drop-out). A cost-effectiveness analysis will incorporate intervention costs to compare overall health care costs and quality of life years between treatment arms. An embedded study will examine the impact of past trauma and engagement in safety behaviours and distress on the main outcomes. DISCUSSION: This trial should provide data on the clinical and cost-effectiveness of a CBT-informed psychological therapy for older victims of crime with anxiety and/or depressive symptoms and should demonstrate a model of integrated cross-agency working. Our findings should provide evidence for policy-makers, commissioners and clinicians responding to the needs of older victims of crime. TRIAL REGISTRATION: International Standard Randomised Controlled Trials Number, ID: ISRCTN16929670. Registered on 3 August 2016

    Evaluation of a New Recombinant K39 Rapid Diagnostic Test for Sudanese Visceral Leishmaniasis.

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    A new rK39 rapid diagnostic dipstick test (DiaMed-IT-Leish) was compared with aspiration and a direct agglutination test (DAT) for diagnosis of visceral leishmaniasis (VL) in 201 parasitologically confirmed cases, 133 endemic controls, and in 356 clinical suspects in disease-endemic and -epidemic areas in Sudan. The sensitivity of the rK39 test in parasitologically confirmed VL cases was 90%, whereas the specificity in disease-endemic controls was 99%. The sensitivity of the DAT was 98%. In clinically suspected cases, the sensitivity of the rK39 test was 81% and the specificity was 97%. When compared with the diagnostic protocol based on the DAT and aspiration used by Médecins sans Frontières in epidemic situations, the positive predictive value was 98%, and the negative predictive value was 71%. This rK39 rapid diagnostic test is suitable for screening as well as diagnosis of VL. Further diagnostic work-up of dipstick-negative patients with clinically suspected VL is important. The ease and convenience of the dipstick test will allow decentralization and improved access to care in disease-endemic areas in Sudan
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