5,086 research outputs found

    A high-resolution infrared spectroscopic investigation of the halogen atom-HCN entrance channel complexes solvated in superfluid helium droplets

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    Rotationally resolved infrared spectra are reported for the X-HCN (X = Cl, Br, I) binary complexes solvated in helium nanodroplets. These results are directly compared with that obtained previously for the corresponding X-HF complexes [J. M. Merritt, J. K\"upper, and R. E. Miller, PCCP, 7, 67 (2005)]. For bromine and iodine atoms complexed with HCN, two linear structures are observed and assigned to the 2Σ1/2^{2}\Sigma_{1/2} and 2Π3/2^{2}\Pi_{3/2} ground electronic states of the nitrogen and hydrogen bound geometries, respectively. Experiments for HCN + chlorine atoms give rise to only a single band which is attributed to the nitrogen bound isomer. That the hydrogen bound isomer is not stabilized is rationalized in terms of a lowering of the isomerization barrier by spin-orbit coupling. Theoretical calculations with and without spin-orbit coupling have also been performed and are compared with our experimental results. The possibility of stabilizing high-energy structures containing multiple radicals is discussed, motivated by preliminary spectroscopic evidence for the di-radical Br-HCCCN-Br complex. Spectra for the corresponding molecular halogen HCN-X2_{2} complexes are also presented.Comment: 20 pages, 15 figures, 6 tables, RevTe

    Pancreatic cysts suspected to be branch duct intraductal papillary mucinous neoplasm without concerning features have low risk for development of pancreatic cancer.

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    BackgroundThe risk of developing pancreatic cancer is uncertain in patients with clinically suspected branch duct intraductal papillary mucinous neoplasm (BD-IPMN) based on the "high-risk stigmata" or "worrisome features" criteria proposed in the 2012 international consensus guidelines ("Fukuoka criteria").MethodsRetrospective case series involving patients referred for endoscopic ultrasound (EUS) of indeterminate pancreatic cysts with clinical and EUS features consistent with BD-IPMN. Rates of pancreatic cancer occurring at any location in the pancreas were compared between groups of patients with one or more Fukuoka criteria ("Highest-Risk Group", HRG) and those without these criteria ("Lowest-Risk Group", LRG).ResultsAfter exclusions, 661 patients comprised the final cohort (250 HRG and 411 LRG patients), 62% female with an average age of 67 years and 4 years of follow up. Pancreatic cancer, primarily adenocarcinoma, occurred in 60 patients (59 HRG, 1 LRG). Prevalent cancers diagnosed during EUS, immediate surgery, or first year of follow up were found in 48/661 (7.3%) of cohort and exclusively in HRG (33/77, 42.3%). Using Kaplan-Meier method, the cumulative incidence of cancer at 7 years was 28% in HRG and 1.2% in LRG patients (P<0.001).ConclusionsThis study supports using Fukuoka criteria to stratify the immediate and long-term risks of pancreatic cancer in presumptive BD-IPMN. The risk of pancreatic cancer was highest during the first year and occurred exclusively in those with "high-risk stigmata" or "worrisome features" criteria. After the first year all BD-IPMN continued to have a low but persistent cancer risk

    Distinctiveness and encoding effects in online sentence comprehension

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    In explicit memory recall and recognition tasks, elaboration and contextual isolation both facilitate memory performance. Here, we investigate these effects in the context of sentence processing: targets for retrieval during online sentence processing of English object relative clause constructions differ in the amount of elaboration associated with the target noun phrase, or the homogeneity of superficial features (text color). Experiment 1 shows that greater elaboration for targets during the encoding phase reduces reading times at retrieval sites, but elaboration of non-targets has considerably weaker effects. Experiment 2 illustrates that processing isolated superficial features of target noun phrases --- here, a green word in a sentence with words colored white --- does not lead to enhanced memory performance, despite triggering longer encoding times. These results are interpreted in the light of the memory models of Nairne 1990, 2001, 2006, which state that encoding remnants contribute to the set of retrieval cues that provide the basis for similarity-based interference effects

    Being the ‘med reg’: an exploration of junior doctors’ perceptions of the medical registrar role

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    The role of the medical registrar is a challenging one and is acknowledged as being a disincentive to a career in medicine for some junior doctors. We set out to build a broader understanding of the role through exploration of Foundation Doctors’ and Core Medical Trainees’ perceptions of the role. Data, gathered from focus groups, were analysed using a framework approach. Six key themes were identified, which were grouped under the headings ‘perceptions of the medical registrar role’ and ‘transition into the role’. Our work builds on existing literature to inform a deeper understanding of how junior doctors perceive the medical registrar role. In light of our findings we offer suggestions on possible training initiatives to tackle the issues identified. We also highlight positive perceptions of the role and emphasise the key ambassadorial role that current medical registrars have in relation to attracting tomorrows’ medical registrars to the specialty

    The use of paraphrasing in investigative interviews

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    Objective Young children’s descriptions of maltreatment are often sparse thus creating the need for techniques that elicit lengthier accounts. One technique that can be used by interviewers in an attempt to increase children’s reports is ‘paraphrasing’, or repeating information children have disclosed. Although we currently have a general understanding of how paraphrasing may influence children’s reports, we do not have a clear description of how paraphrasing is actually used in the field. Method The present study assessed the use of paraphrasing in 125 interviews of children aged 4 to 16 years conducted by police officers and social workers. All interviewer prompts were coded into four different categories of paraphrasing. All children’s reports were coded for the number of details in response to each paraphrasing statement. Results ‘Expansion paraphrasing’ (e.g., “you said he hit you. Tell me more about when he hit you”) was used significantly more often and elicited significantly more details, while ‘yes/no paraphrasing’ (e.g., “he hit you?”) resulted in shorter descriptions from children, compared to other paraphrasing styles. Further, interviewers more often distorted children’s words when using yes/no paraphrasing, and children rarely corrected interviewers when they paraphrased inaccurately. Conclusions and Practical Implications Investigative interviewers in this sample frequently used paraphrasing with children of all ages and, though children’s responses differed following the various styles of paraphrasing, the effects did not differ by the age of the child witness. The results suggest that paraphrasing affects the quality of statements by child witnesses. Implications for investigative interviewers will be discussed and recommendations offered for easy ways to use paraphrasing to increase the descriptiveness of children’s reports of their experiences

    Polycyclic Aromatic Hydrocarbon and Emission Line Ratios in Active Galactic Nuclei and Starburst Galaxies

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    We study the Polycyclic Aromatic Hydrocarbons (PAH) bands, ionic emission lines, and Mid-infrared continuum properties, in a sample of 171 emission line galaxies taken from literature plus 15 new active galactic nuclei (AGN) Spitzer spectra. The continuum shape steeply rises for longer wavelengths and can be fitted with a warm blackbody distribution of T=150-300K. The brightest PAH spectral bands (6.2, 7.7, 8.6, 11.3, and 12.7μ\mum) and the forbidden emission lines of [Si II] 34.8μ\mum, [Ar II] 6.9, [S III] 18.7 and 33.4 were detected in all the Starbursts and in ~80% of the Seyfert~2. Taking under consideration only the PAH bands at 7.7μ\mum, 11.3μ\mum, and 12.7μ\mum we find they are present in ~80% of the Seyfert 1, while only half of this type of activity show the 6.2μ\mum and 8.6 PAH bands. The observed intensities ratios for neutral and ionized PAHs (6.2/7.7 x 11.3/7.7) were compared to theoretical intensity ratios, showing that AGNs have higher ionization fraction and larger PAH (> 180 carbon atoms) than SB galaxies. The ratio between the ionized (7.7) and the neutral PAH bands (8.6 and 11.3) are distributed over different ranges for AGNs and SB galaxies, suggesting that these ratios could depend on the ionization fraction, as well as on the hardness of the radiation field. The ratio between the 7.7 and 11.3 bands is nearly constant with the increase of [Ne III]15.5/[Ne II], indicating that the fraction of ionized to neutral PAH bands does not depend on the hardness of the radiation field. The equivalent width of both PAH features show the same dependence with [Ne III]/[Ne II], suggesting that the PAH, emitting either ionized (7.7) or neutral (11.3) bands, may be destroyed with the increase of the hardness of the radiation field.Comment: Accepted by Ap

    Why geriatric medicine? A survey of UK specialist trainees in geriatric medicine

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    Background: There is global concern that there are insufficient numbers of geriatricians to meet the needs of the ageing population. A 2005 survey described factors that influenced why UK geriatricians had chosen to specialise in the field - in the decade since, UK postgraduate training has undergone a fundamental restructure. Objective: To explore whether the reasons for choosing a career in geriatric medicine in the UK had changed over time, with the goal of using this knowledge to inform recruitment and training initiatives. Design: An online survey was sent to all UK higher medical trainees in geriatric medicine. Methods: Survey questions that produced categorical data were analysed with simple descriptive statistics. For the survey questions that produced free-text responses, an inductive, iterative approach to analysis, in keeping with the principles of framework analysis, was employed. Results: 269 responses were received out of 641 eligible respondents. Compared with the previous survey, a substantially larger number of respondents regarded geriatric medicine to be their first-choice specialty and a smaller number regretted their career decision. A greater number chose geriatric medicine early in their medical careers. Commitments to the general medical rota and the burden of service provision were considered important downsides to the specialty. Conclusions: There are reasons to be optimistic about recruitment to geriatric medicine. Future attempts to drive up recruitment might legitimately focus on the role of the medical registrar and perceptions that geriatricians shoulder a disproportionate burden of service commitments and obligations to the acute medical take
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