Path integral Monte Carlo simulations for rigid rotors and their application to water

In this work the path integral formulation for rigid rotors, proposed by M\"user and Berne [Phys. Rev. Lett. {\bf 77}, 2638 (1996)], is described in detail. It is shown how this formulation can be used to perform Monte Carlo simulations of water. Our numerical results show that whereas some properties of water can be accurately reproduced using classical simulations with an empirical potential which, implicitly, includes quantum effects, other properties can only be described quantitatively when quantum effects are explicitly incorporated. In particular, quantum effects are extremely relevant when it comes to describing the equation of state of the ice phases at low temperatures, the structure of the ices at low temperatures, and the heat capacity of both liquid water and the ice phases. They also play a minor role in the relative stability of the ice phases.Comment: to appear in Molecular Physics (2011

Dopamine in nucleus accumbens: salience modulation in latent inhibition and overshadowing

Latent inhibition (LI) is demonstrated when non-reinforced pre-exposure to a to-be-conditioned stimulus retards later learning. Learning is similarly retarded in overshadowing, in this case using the relative intensity of competing cues to manipulate associability. Electrolytic/excitotoxic lesions to shell accumbens (NAc) and systemic amphetamine both reliably abolish LI. Here a conditioned emotional response procedure was used to demonstrate LI and overshadowing and to examine the role of dopamine (DA) within NAc. Experiment 1 showed that LI but not overshadowing was abolished by systemic amphetamine (1.0 mg/kg i.p.). In Experiment 2, 6-hydroxydopamine (6-OHDA) was used to lesion DA terminals within NAc: both shell- and core- (plus shell-)lesioned rats showed normal LI and overshadowing. Experiment 3 compared the effects of amphetamine microinjected at shell and core coordinates prior to conditioning: LI, but not overshadowing, was abolished by 10.0 but not 5.0 µg/side amphetamine injected in core but not shell NAc. These results suggest that the abolition of LI produced by NAc shell lesions is not readily reproduced by regionally restricted DA depletion within NAc; core rather than shell NAc mediates amphetamine-induced abolition of LI; overshadowing is modulated by different neural substrates

The accuracy of the Jamaican national physician register: a study of the status of physicians registered and their countries of training

<p>Abstract</p> <p>Background</p> <p>The number of physicians per 10,000 population is a basic health indicator used to determine access to health care. Studies from the United States of America and Europe indicate that their physician registration databases may be flawed. Clinical research activities have suggested that the current records of physicians registered to practice in Jamaica may not be accurate. Our objective was to determine whether the Medical Council of Jamaica (MCJ) accurately records and reports the identities, number and specialty designation of physicians in Jamaica. An additional aim was to determine the countries in which these physicians were trained.</p> <p>Methods</p> <p>Data regarding physicians practicing in Jamaica in 2005 were obtained from multiple sources including the MCJ and the telephone directory. Intense efforts at tracing were undertaken in a sub-sample of physicians, internists and paediatricians to further improve the accuracy of the data. Data were analysed using SPSS, version 11.5.</p> <p>Results</p> <p>The MCJ listed 2667 registered physicians of which 118 (4.4%) were no longer practicing in Jamaica. Of the subset of 150 physicians who were more actively traced, an additional 11 were found to be no longer in practice. Thus at least 129 (4.8%) of the physicians on the MCJ list were not actively practising in Jamaica. Twenty-nine qualified physicians who were in practice, but not currently on the Jamaican register, were identified from other data sources. This yielded an estimate of 2567 physicians or 9.68 physicians per 10,000 persons. Seven hundred and twenty six specialists were identified, 118 from the MCJ list only, 452 from other sources, in particular medical associations, and 156 from both the MCJ list and other sources. Sixty-six percent of registered doctors completed medical school at the University of the West Indies (UWI).</p> <p>Conclusion</p> <p>These data suggest that the MCJ list includes some physicians no longer practicing in Jamaica while underestimating the number of specialists. Difficulty in accurately estimating the number of practicing physicians has been reported in studies done in other countries but the under-reporting of the number of specialists is uncommon. Additional consideration should be given to strategies to ensure compliance with the annual registration that is mandated by law and to changing the law to include registration of specialist qualifications.</p

A 4.3 GHz BiCMOS VCO with multiple 360° variable phase outputs using the vector sum method

A 4.3 GHz voltage controlled oscillator (VCO) with multiple independently tunable phase outputs is presented. The VCO is realized by coupling two LC oscillators together in order to obtain quadrature signals and is tunable between 4.12 and 4.74 GHz. The variable phase outputs are achieved by varying the amplitudes of the in-phase and quadrature signals independently and then combining these signals together. By using multiple Gilbert cells as variable gain amplifiers (VGAs), multiple tunable phase outputs are achieved with the use of only one quadrature VCO. The VGAs are controlled using a custom non-linear digital-toanalog converter. The entire circuit is designed using a 3.3 V SiGe BiCMOS process. A maximum phase noise of -108.17 dBc/Hz was measured over the entire tuning range at a 1 MHz offset. The outputs of the VCO can be used as local oscillators that achieve phase shifting during radio frequency up or down conversion.Armscor S. A. Ltd and the Business Unit: Defence, Peace, Safety and Security (DPSS), Council for Scientific and Industrial Research (CSIR), South Africa.http://www.springerlink.com/content/0925-1030ai201

Sonosensitive cavitation nuclei-a customisable platform technology for enhanced therapeutic delivery

Ultrasound-mediated cavitation shows great promise for improving targeted drug delivery across a range of clinical applications. Cavitation nuclei-sound-sensitive constructs that enhance cavitation activity at lower pressures-have become a powerful adjuvant to ultrasound-based treatments, and more recently emerged as a drug delivery vehicle in their own right. The unique combination of physical, biological, and chemical effects that occur around these structures, as well as their varied compositions and morphologies, make cavitation nuclei an attractive platform for creating delivery systems tuned to particular therapeutics. In this review, we describe the structure and function of cavitation nuclei, approaches to their functionalization and customization, various clinical applications, progress toward real-world translation, and future directions for the field

Effects of acute fatigue on the volitional and magnetically-evoked electromechanical delay of the knee flexors in males and females

Neuromuscular performance capabilities, including those measured by evoked responses, may be adversely affected by fatigue; however, the capability of the neuromuscular system to initiate muscle force rapidly under these circumstances is yet to be established. Sex-differences in the acute responses of neuromuscular performance to exercise stress may be linked to evidence that females are much more vulnerable to ACL injury than males. Optimal functioning of the knee flexors is paramount to the dynamic stabilisation of the knee joint, therefore the aim of this investigation was to examine the effects of acute maximal intensity fatiguing exercise on the voluntary and magnetically-evoked electromechanical delay in the knee flexors of males and females. Knee flexor volitional and magnetically-evoked neuromuscular performance was assessed in seven male and nine females prior to and immediately after: (i) an intervention condition comprising a fatigue trial of 30-seconds maximal static exercise of the knee flexors, (ii) a control condition consisting of no exercise. The results showed that the fatigue intervention was associated with a substantive reduction in volitional peak force (PFV) that was greater in males compared to females (15.0%, 10.2%, respectively, p < 0.01) and impairment to volitional electromechanical delay (EMDV) in females exclusively (19.3%, p < 0.05). Similar improvements in magnetically-evoked electromechanical delay in males and females following fatigue (21%, p < 0.001), however, may suggest a vital facilitatory mechanism to overcome the effects of impaired voluntary capabilities, and a faster neuromuscular response that can be deployed during critical times to protect the joint system

Cochlear implantation in patients with chronic otitis media: 7 years’ experience in Maastricht

The purpose of this paper is to propose management options for cochlear implantation in chronic otitis media (COM) based on our 7-year experience. Thirteen patients with COM who were candidates for cochlear implantation were identified. COM was divided in an inactive and an active form based on clinical and radiological findings. One major complications and one minor complication were identified in the study group. In case of an active infection or in case of a unstable cavity we advise cochlear implantation as a staged procedure. A single stage procedure is recommended in case of patients with COM presenting with a dry perforation or a stable cavity

Complete chloroplast genome sequence of Holoparasite Cistanche Deserticola (Orobanchaceae) reveals gene loss and horizontal gene transfer from Its host Haloxylon Ammodendron (Chenopodiaceae)

The central function of chloroplasts is to carry out photosynthesis, and its gene content and structure are highly conserved across land plants. Parasitic plants, which have reduced photosynthetic ability, suffer gene losses from the chloroplast (cp) genome accompanied by the relaxation of selective constraints. Compared with the rapid rise in the number of cp genome sequences of photosynthetic organisms, there are limited data sets from parasitic plants. The authors report the complete sequence of the cp genome of Cistanche deserticola, a holoparasitic desert species belonging to the family Orobanchaceae

從中文作文看學生的情意表達能力: 個案研究

本文是一個追蹤研究，首先收集研究對象中一至中三的作文103篇，並採用現象學研究法（Phenomenological Research ）的意念進行研究。現象學研究法的重點在於深入了解人類自然的生活，把沒有虛飾的生活體驗和意義呈現出來。本文主要運用兩種分析工具：威堅遜模式（Wilkinson， 1980）及內容分析（text analysis）。論文研究的目的：分析受試者初中情意表達能力的層次。 This article is a longitudinal research which monitors 103 essays of a student from F.1 to F.3 by adopting 'phenomenological research'. Phenomenological research is based on the deep understanding of human life, presenting us with the truest life experiences without disguise. The ability to express emotion of a student as reflected from his Chinese composition. Two models are employed in this research: Wilkinson’s (1980) and text analysis. The objectives of this research is to analyse the abilities of junior secondary school students to express emotions.link_to_OA_fulltex

Smc5/6 coordinates formation and resolution of joint molecules with chromosome morphology to ensure meiotic divisions

During meiosis, Structural Maintenance of Chromosome (SMC) complexes underpin two fundamental features of meiosis: homologous recombination and chromosome segregation. While meiotic functions of the cohesin and condensin complexes have been delineated, the role of the third SMC complex, Smc5/6, remains enigmatic. Here we identify specific, essential meiotic functions for the Smc5/6 complex in homologous recombination and the regulation of cohesin. We show that Smc5/6 is enriched at centromeres and cohesin-association sites where it regulates sister-chromatid cohesion and the timely removal of cohesin from chromosomal arms, respectively. Smc5/6 also localizes to recombination hotspots, where it promotes normal formation and resolution of a subset of joint-molecule intermediates. In this regard, Smc5/6 functions independently of the major crossover pathway defined by the MutLγ complex. Furthermore, we show that Smc5/6 is required for stable chromosomal localization of the XPF-family endonuclease, Mus81-Mms4Eme1. Our data suggest that the Smc5/6 complex is required for specific recombination and chromosomal processes throughout meiosis and that in its absence, attempts at cell division with unresolved joint molecules and residual cohesin lead to severe recombination-induced meiotic catastroph