The Asymmetric Rotor. IX. The Heavy Water Bands at 2787 cm^–1 and 5373 cm^–1

The combination band (110) of the two stretching fundamentals of D2O is reported and analyzed to yield nu0=5373.2 cm^–1 and the excited state moments of inertia 1.910, 3.931, and 5.929×10^–40 g cm^2. The same method of analysis applied to the unsymmetrical fundamental band (100) envelope gives nu0=2787.5 cm^–1 and the excited state moments 1.881, 3.876, and 5.843×10^–40 g cm^2

Animal Behaviour: Strategic Signalling by Cephalopods

SummaryCuttlefish are masters of disguise, rapidly changing colour to blend with their backgrounds. A new study shows that they break camouflage to direct warning messages at certain predators, but only those likely to be dissuaded by visual signals

The Dynamics of Radiative Shock Waves: Linear and Nonlinear Evolution

The stability properties of one-dimensional radiative shocks with a power-law cooling function of the form $\Lambda \propto \rho^2T^\alpha$ are the main subject of this work. The linear analysis originally presented by Chevalier & Imamura, is thoroughfully reviewed for several values of the cooling index $\alpha$ and higher overtone modes. Consistently with previous results, it is shown that the spectrum of the linear operator consists in a series of modes with increasing oscillation frequency. For each mode a critical value of the cooling index, $\alpha_\textrm{c}$, can be defined so that modes with $\alpha < \alpha_\textrm{c}$ are unstable, while modes with $\alpha > \alpha_\textrm{c}$ are stable. The perturbative analysis is complemented by several numerical simulations to follow the time-dependent evolution of the system for different values of $\alpha$. Particular attention is given to the comparison between numerical and analytical results (during the early phases of the evolution) and to the role played by different boundary conditions. It is shown that an appropriate treatment of the lower boundary yields results that closely follow the predicted linear behavior. During the nonlinear regime, the shock oscillations saturate at a finite amplitude and tend to a quasi-periodic cycle. The modes of oscillations during this phase do not necessarily coincide with those predicted by linear theory, but may be accounted for by mode-mode coupling.Comment: 33 pages, 12 figures, accepted for publication on the Astrophysical Journa

Destabilization of a Solar Prominence/Filament Field System by a Series of Eight Homologous Eruptive Flares

Homologous flares are flares that occur repetitively in the same active region, with similar structure and morphology. A series of at least eight homologous flares occurred in active region NOAA 11237 over 16 - 17 June 2011. A nearby prominence/filament was rooted in the active region, and situated near the bottom of a coronal cavity. The active region was on the southeast solar limb as seen from SDO/AIA, and on the disk as viewed from STEREO/EUVI-B. The dual perspective allows us to study in detail behavior of the prominence/filament material entrained in the magnetic field of the repeatedly-erupting system. Each of the eruptions was mainly confined, but expelled hot material into the prominence/filament cavity system (PFCS). The field carrying and containing the ejected hot material interacted with the PFCS and caused it to inflate, resulting in a step-wise rise of the PFCS approximately in step with the homologous eruptions. The eighth eruption triggered the PFCS to move outward slowly, accompanied by a weak coronal dimming. As this slow PFCS eruption was underway, a final ejective flare occurred in the core of the active region, resulting in strong dimming in the EUVI-B images and expulsion of a coronal mass ejection (CME). A plausible scenario is that the repeated homologous flares could have gradually destabilized the PFCS, and its subsequent eruption removed field above the acitive region and in turn led to the ejective flare, strong dimming, and CME.Comment: 11 pages, 12 figures, Accepted for publication in Ap

Numerical simulation of dark lanes in post-flare supra-arcade

We integrate the MHD ideal equations to simulate dark void sunwardly moving structures in post--flare supra--arcades. We study the onset and evolution of the internal plasma instability to compare with observations and to gain insight into physical processes and characteristic parameters of these phenomena. The numerical approach uses a finite-volume Harten-Yee TVD scheme to integrate the 1D1/2 MHD equations specially designed to capture supersonic flow discontinuities. The integration is performed in both directions, the sunward radial one and the transverse to the magnetic field. For the first time, we numerically reproduce observational dark voids described in Verwichte et al. (2005). We show that the dark tracks are plasma vacuums generated by the bouncing and interfering of shocks and expansion waves, upstream an initial slow magnetoacoustic shock produced by a localized deposition of energy modeled with a pressure perturbation. The same pressure perturbation produces a transverse to the field or perpendicular magnetic shock giving rise to nonlinear waves that compose the kink--like plasma void structures, with the same functional sunward decreasing phase speed and constancy with height of the period, as those determined by the observations.Comment: Accepted MNRAS, 6 pages, 7 figure

Orientation to the sun by animals and its interaction with crypsis

1. Orientation with respect to the sun has been observed in a wide range of species and hasgenerally been interpreted in terms of thermoregulation and/or ultraviolet (UV) protection. For countershaded animals, orientation with respect to the sun may also result from the pres-sure to exploit the gradient of coloration optimally to enhance crypsis.2. Here, we use computational modelling to predict the optimal countershading pattern for anoriented body. We assess how camouflage performance declines as orientation varies using acomputational model that incorporates realistic lighting environments.3. Once an optimal countershading pattern for crypsis has been chosen, we determineseparately how UV protection/irradiation and solar thermal inflow fluctuate with orientation.4. We show that body orientations that could optimally use countershading to enhance crypsisare very similar to those that allow optimal solar heat inflow and UV protection.5. Our findings suggest that crypsis has been overlooked as a selective pressure on orientationand that new experiments should be designed to tease apart the respective roles of these different selective pressures. We propose potential experiments that could achieve this

The unsuitability of html-based colour charts for estimating animal colours - a comment on Berggren and Merilä (2004)

BACKGROUND: A variety of techniques are used to study the colours of animal signals, including the use of visual matching to colour charts. This paper aims to highlight why they are generally an unsatisfactory tool for the measurement and classification of animal colours and why colour codes based on HTML (really RGB) standards, as advocated in a recent paper, are particularly inappropriate. There are many theoretical arguments against the use of colour charts, not least that human colour vision differs markedly from that of most other animals. However, the focus of this paper is the concern that, even when applied to humans, there is no simple 1:1 mapping from an RGB colour space to the perceived colours in a chart (the results are both printer- and illumination-dependent). We support our criticisms with data from colour matching experiments with humans, involving self-made, printed colour charts. RESULTS: Colour matching experiments with printed charts involving 11 subjects showed that the choices made by individuals were significantly different between charts that had exactly the same RGB values, but were produced from different printers. Furthermore, individual matches tended to vary under different lighting conditions. Spectrophotometry of the colour charts showed that the reflectance spectra of the charts varied greatly between printers and that equal steps in RGB space were often far from equal in terms of reflectance on the printed charts. CONCLUSION: In addition to outlining theoretical criticisms of the use of colour charts, our empirical results show that: individuals vary in their perception of colours, that different printers produce strikingly different results when reproducing what should be the same chart, and that the characteristics of the light irradiating the surface do affect colour perception. Therefore, we urge great caution in the use of colour charts to study animal colour signals. They should be used only as a last resort and in full knowledge of their limitations, with specially produced charts made to high industry standards

Dementia training programmes for staff working in general hospital settings – a systematic review of the literature

Objectives: There has been an increased interest in dementia training programmes directed to general hospitals, partly due to the reported lack of staff training that may be contributing to poor quality of care. Although literature describing and evaluating training programmes in hospital settings increased in recent years, there are no reviews that summarise these programmes. This review sought to address this, by collecting the current evidence on dementia training programmes directed to staff working in general hospitals. Method: Literature from five databases (PubMed, Academic Search Complete, PsychInfo, CINAHL and AgeLine) were searched, based on a number of inclusion criteria. The selected studies were summarised and data was extracted and compared using narrative synthesis based on a set of pre-defined categories. Methodological quality was assessed using Kmet, Lee &amp; Cook (2004) criteria. Results: Fourteen peer-reviewed studies were identified with the majority being pre-test post-test investigations. No randomised controlled trials were found. Methodological quality was variable with selection bias being the major limitation. There was a great variability in the development and mode of delivery although, interdisciplinary ward based, tailor-made, short sessions using experiential and active learning, were the most utilized approaches. The majority of the studies mainly evaluated learning, with few studies evaluating changes in staff behaviour/practices and patients’ outcomes. Conclusion: This review indicates that high quality studies are needed that especially evaluate staff behaviours and patient outcomes and their sustainability over time. This review also highlights measures that could be used to develop and deliver training programmes in hospital settings

The perceived and observed needs of patients with dementia admitted to acute medical wards

It is acknowledged that the needs of persons living with dementia admitted in acute hospitals are not always met. Previous studies have focused on the perceived needs of professional caregivers or family members whilst the voices of patients with dementia in acute hospitals has not been extensively reported. This may have contributed to the under-recognition of the needs of persons living with dementia. The aim of this study was to categorize the perceived and observed needs of persons with dementia admitted in acute medical wards and to explore whether these needs are being or have been met. Thirteen people with dementia in three medical wards who could verbally communicate with the researcher, were purposively selected as research participants. Semi-structured interviews were conducted to elicit each participant’s experiences of their hospital stay and whether their needs were perceived to have been/are being met. Moreover, routine care with the same participants was observed using Dementia Care Mapping. Maslow’s Hierarchy of Needs, was used as a framework to categorize care needs. Our findings demonstrate that basic needs such as toileting, feeding, drinking, continence and comfort were not always met. Moreover, the largest gap between met and unmet needs was found in patients who were either under constant observation or unable to communicate. Too much emphasis was perceived and observed to be given on what staff considered as safety needs at the expense of other needs. The patients’ need for social contact and self-esteem such as dignity and respect were often ignored and this led to patients feeling devalued. Hospital staff have to be more aware of the holistic needs of patients with dementia in acute settings and the way care is delivered in order to make up for these unmet needs thus facilitating person-centred care