26,514 research outputs found

    Thermal conductivity and resonant multipole interactions

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    The influence of multipole interactions on exchanges of rotational energy in molecular collisions was investigated by means of a simple two-state impact parameter approximation. The calculations are restricted to linear molecules and to dipole and quadrupole fields. The effects of such exchanges on the thermal conductivity of gases and of gaseous mixtures was investigated, after correcting the kinetic theory of mixtures to include exchanges between unlike molecules. It was found that dipole-quadrupole and quadrupole-quadrupole interactions may have a significant effect for molecules with low moments of inertia. In particular, quadrupole interactions are important in the hydrogen isotopes, and the calculated corrections for H2 are consistent with recent experimental work by Harris. The theory seems capable of accounting for the anomalies observed in HF + DF and HCl + DCl mixtures in terms of multipolar accidental resonances

    Predictive validity of the HCR-20 for inpatient aggression:the effect of intellectual disability on accuracy

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    BackgroundPeople with intellectual disability (ID) account for a large proportion of aggressive incidents in secure and forensic psychiatric services. Although the Historical, Clinical, Risk Management 20 (HCR-20) has good predictive validity in inpatient settings, it does not perform equally in all groups and there is little evidence for its efficacy in those with ID.MethodA pseudo-prospective cohort study of the predictive efficacy of the HCR-20 for those with ID (n = 109) was conducted in a UK secure mental health setting using routinely collected risk data. Performance of the HCR-20 in the ID group was compared with a comparison group of adult inpatients without an ID (n = 504). Analysis controlled for potential covariates including security level, length of stay, gender and diagnosis.ResultsThe HCR-20 total score was a significant predictor of any aggression and of physical aggression for both groups, although the area under the curve values did not reach the threshold for a large effect size. The clinical subscale performed significantly better in those without an ID compared with those with. The ID group had a greater number of relevant historical and risk management items. The clinicians' summary judgment significantly predicted both types of aggressive outcomes in the ID group, but did not predict either in those without an ID.ConclusionsThis study demonstrates that, after controlling for a range of potential covariates, the HCR-20 is a significant predictor of inpatient aggression in people with an ID and performs as well as for a comparison group of mentally disordered individuals without ID. The potency of HCR-20 subscales and items varied between the ID and comparison groups suggesting important target areas for improved prediction and risk management interventions in those with ID

    Heat Conductivity of Polyatomic and Polar Gases and Gas Mixtures

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    Theory for calculating heat conductivity of polyatomic and polar gases and gas mixture

    Maternal caregivers have confluence of altered cortisol, high reward-driven eating, and worse metabolic health.

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    Animal models have shown that chronic stress increases cortisol, which contributes to overeating of highly palatable food, increased abdominal fat and lower cortisol reactivity. Few studies in humans have simultaneously examined these trajectories. We examined premenopausal women, either mothers of children with a diagnosis of an autism spectrum disorder (n = 92) or mothers of neurotypical children (n = 91). At baseline and 2-years, we assessed hair cortisol, metabolic health, and reward-based eating. We compared groups cross-sectionally and prospectively, accounting for BMI change. Caregivers, relative to controls, had lower cumulative hair cortisol at each time point, with no decreases over time. Caregivers also had stable levels of poor metabolic functioning and greater reward-based eating across both time points, and evidenced increased abdominal fat prospectively (all ps ≤.05), independent of change in BMI. This pattern of findings suggest that individuals under chronic stress, such as caregivers, would benefit from tailored interventions focusing on better regulation of stress and eating in tandem to prevent early onset of metabolic disease, regardless of weight status

    Measurement of Newtonian fluid slip using a torsional ultrasonic oscillator

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    The composite torsional ultrasonic oscillator, a versatile experimental system, can be used to investigate slip of Newtonian fluid at a smooth surface. A rigorous analysis of slip-dependent damping for the oscillator is presented. Initially, the phenomenon of finite surface slip and the slip length are considered for a half-space of Newtonian fluid in contact with a smooth, oscillating solid surface. Definitions are revisited and clarified in light of inconsistencies in the literature. We point out that, in general oscillating flows, Navier's slip length b is a complex number. An intuitive velocity discontinuity parameter of unrestricted phase is used to describe the effect of slip on measurement of viscous shear damping. The analysis is applied to the composite oscillator and preliminary experimental work for a 40 kHz oscillator is presented. The Non-Slip Boundary Condition (NSBC) has been verified for a hydrophobic surface in water to within ~60 nm of |b|=0 nm. Experiments were carried out at shear rate amplitudes between 230 and 6800 /s, corresponding to linear displacement amplitudes between 3.2 and 96 nm.Comment: Revised with minor edits for revie

    Extended Molecular Gas in the Nearby Starburst Galaxy Maffei 2

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    We present a 9'x9' fully-sampled map of the CO J=1-0 emission in the nearby starburst galaxy Maffei 2 obtained at the Five College Radio Astronomy Observatory. The map reveals previously known strong CO emission in the central starburst region as well as an extended asymmetric distribution with bright CO lines at the ends of the bar and in a feature at the north-east edge of the molecular disk. This northern feature, proposed previously to be an interacting companion galaxy, could be a dwarf irregular galaxy, although the CO data are also consistent with the feature being simply an extension of one of the spiral arms. We estimate the total molecular gas mass of Maffei 2 to be (1.4-1.7)x10^9 Mo or ~3-4% of its dynamical mass. Adopting the recently determined lower value for the CO-to-H2 conversion factor in the central region, our data lead to the surprising result that the largest concentrations of molecular gas in Maffei 2 lie at the bar ends and in the putative dwarf companion rather than in the central starburst. A gravitational stability analysis reveals that the extended disk of Maffei 2 lies above the critical density for star formation; however, whether the central region is also gravitationally unstable depends both on the details of the rotation curve and the precise value of the CO-to-H2 conversion factor in this region.Comment: accepted to ApJ (Sept 10 2004 issue

    Predictive validity of the HCR-20 for violent and non-violent sexual behaviour in a secure mental health service

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    BackgroundViolent and non-violent sexual behaviour is a fairly common problem among secure mental health service patients, but specialist sexual violence risk assessment is time-consuming and so performed infrequently.AimsWe aimed to establish whether a commonly used violence risk assessment tool, the Health Clinical Risk management 20(HCR-20), has predictive validity specifically for inappropriate sexual behaviour.MethodsA pseudo-prospective cohort design was used for a study in the adult wards of a large provider of specialist secure mental health services. Routine clinical team HCR-20 assessments were extracted from records, and incidents involving inappropriate sexual behaviour were recorded for the 3 months following assessment.ResultsOf 613 patients, 104 (17%) had engaged in at least one inappropriate sexual behaviour; in 65 (10.6%), the sexual act was violent. HCR-20 total score, clinical and risk management subscales, predicted violent and non-violent sexual behaviour. The negative predictive value of the HCR-20 for inappropriate sexual behaviour was over 90%.ConclusionsPrediction of violent sexual behaviour may be regarded as well within the scope of the HCR-20 as a structured professional judgement tool to aid violence risk prediction, but we found that it also predicts behaviours that may be of concern but fall below the violence threshold. High negative predictive values suggest that HCR-20 scores may have some utility for screening out patients who do not require more specialist assessment for inappropriate sexual behaviour

    Signatures of the non-Maxwellian κ\kappa-distributions in optically thin line spectra. II. Synthetic Fe XVII--XVIII X-ray coronal spectra and predictions for the Marshall Grazing-Incidence X-ray Spectrometer (MaGIXS)

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    We investigated the possibility of diagnosing the degree of departure from the Maxwellian distribution using the Fe XVII - Fe XVIII spectra originating in plasmas in collisional ionization equilibrium, such as in the cores of solar active regions or microflares. The original collision strengths for excitation are integrated over the non-Maxwellian electron κ\kappa-distributions characterized by a high-energy tail. Synthetic X-ray emission line spectra were calculated for a range of temperatures and κ\kappa. We focus on the 6-24 A spectral range to be observed by the upcoming Marshall Grazing-Incidence X-ray Spectrometer MaGIXS. We find that many line intensity ratios are sensitive to both TT and κ\kappa. Best diagnostic options are provided if a ratio involving both Fe XVII and Fe XVIII is combined with another ratio involving lines formed within a single ion. The sensitivity of such diagnostics to κ\kappa is typically a few tens of per cent. Much larger sensitivity, of about a factor of two to three, can be obtained if the Fe XVIII 93.93 A line observed by SDO/AIA is used in conjuction with the X-ray lines. We conclude that the MaGIXS instrument is well-suited for detection of departures from the Maxwellian distribution, especially in active region cores.Comment: Astronomy & Astrophysics, accepte
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