Magnetic dipole transition rates from measured lifetimes of levels of Be-like and B-like argon ions

Journals published by the American Physical Society can be found at http://publish.aps.org/The lifetimes of the 1s(2)2s2p P-3(2) level of Ar XV and 1s(2)2s(2)2p P-2(3/2) of Ar XIV have been measured using metastable Ar14+ and Ar13+ ions produced by an electron cyclotron resonance ion source, which were subsequently separately captured into a Kingdon ion trap. The lifetime results are tau(Ar XV, 2s2p P-3(2)) = 13.4(7) ms and tau(Ar XIV,2p P-2(3/2)) = 9.12(18) ms. Transition rates derived from the measured lifetimes differ significantly from both relativistic and nonrelativistic calculations of the 2s2p P-3(1)-P-3(2) M1 transition rate of Ar XV, but are in reasonable agreement with calculations for the 2p P-2(1/2)-P-2(3/2) M1 rate of Ar XIV. [S1050-2947(98)07108-X

Measured lifetimes of metastable levels of Mn X, Mn XI, Mn XII, and Mn XIII ions

Journals published by the American Physical Society can be found at http://publish.aps.org/An ion storage technique, based on the capture of metastable multiply charged ions from an external ion source into a Kingdon ion trap, has been used to measure the lifetimes of eight metastable levels of Mn ions with 3s(2)3p(k) configurations, k = 1 - 4. Although several lifetime calculations exist, some of the transition wavelengths have not been previously observed in any source. The lifetimes range from 1.5-35 ms. A measurement precision as good as 0.9% was obtained in favorable cases. The measured lifetimes are tau(Mn X, 3s(2)3p(4) S-1(0)) = 2.1 +/- 0.3, tau(Mn X, 3s(2)3p(4) D-1(2)) = 18.02 +/- 0.16, tau(Mn XI, 3s(2)3p(3) P-2(3/2)) = 3.0 +/- 0.2, tau(Mn XI, 3s(2)3p(3) P-2(1/2)) = 6.17 +/- 0.29, tau(Mn XI, 3s(2)3p(3) D-2(3/2)) = 35.1 +/- 1.43, tau(Mn XII. 3S(2)3p(2) S-1(0)) = 1.5 +/- 0.2, tau(Mn XII, 3s(2)3p(2) D-1(2)) = 11.16 +/- 0.10, and tau(Mn XII, 3s(2)3p P-2(3/2)) = 31.32 +/- 1.82 ms. These results are compared with the existing theoretical calculations, which have estimated uncertainties no better than 25%. [S1050-2947(99)102903-0]

TRIDENT: an Infrared Differential Imaging Camera Optimized for the Detection of Methanated Substellar Companions

A near-infrared camera in use at the Canada-France-Hawaii Telescope (CFHT) and at the 1.6-m telescope of the Observatoire du Mont-Megantic is described. The camera is based on a Hawaii-1 1024x1024 HgCdTe array detector. Its main feature is to acquire three simultaneous images at three wavelengths across the methane absorption bandhead at 1.6 microns, enabling, in theory, an accurate subtraction of the stellar point spread function (PSF) and the detection of faint close methanated companions. The instrument has no coronagraph and features fast data acquisition, yielding high observing efficiency on bright stars. The performance of the instrument is described, and it is illustrated by laboratory tests and CFHT observations of the nearby stars GL526, Ups And and Chi And. TRIDENT can detect (6 sigma) a methanated companion with delta H = 9.5 at 0.5" separation from the star in one hour of observing time. Non-common path aberrations and amplitude modulation differences between the three optical paths are likely to be the limiting factors preventing further PSF attenuation. Instrument rotation and reference star subtraction improve the detection limit by a factor of 2 and 4 respectively. A PSF noise attenuation model is presented to estimate the non-common path wavefront difference effect on PSF subtraction performance.Comment: 41 pages, 16 figures, accepted for publication in PAS

Prevalence of disorders recorded in Cavalier King Charles Spaniels attending primary-care veterinary practices in England

Background: Concerns have been raised over breed-related health issues in purebred dogs, but reliable prevalence estimates for disorders within specific breeds are sparse. Electronically stored patient health records from primary-care practice are emerging as a useful source of epidemiological data in companion animals. This study used large volumes of health data from UK primary-care practices participating in the VetCompass animal health surveillance project to evaluate in detail the disorders diagnosed in a random selection of over 50% of dogs recorded as Cavalier King Charles Spaniels (CKCSs). Confirmation of breed using available microchip and Kennel Club (KC) registration data was attempted. Results: In total, 3624 dogs were recorded as CKCSs within the VetCompass database of which 143 (3.9%) were confirmed as KC-registered via microchip identification linkage of VetCompass to the KC database. 1875 dogs (75 KC registered and 1800 of unknown KC status, 52% of both groups) were randomly sampled for detailed clinical review. Clinical data associated with veterinary care were recorded in 1749 (93.3%) of these dogs. The most common specific disorders recorded during the study period were heart murmur (541 dogs, representing 30.9% of study group), diarrhoea of unspecified cause (193 dogs, 11.0%), dental disease (166 dogs, 9.5%), otitis externa (161, 9.2%), conjunctivitis (131, 7.4%) and anal sac infection (129, 7.4%). The five most common disorder categories were cardiac (affecting 31.7% of dogs), dermatological (22.2%), ocular (20.6%), gastrointestinal (19.3%) and dental/periodontal disorders (15.2%). Discussion and conclusions: Study findings suggest that many of the disorders commonly affecting CKCSs are largely similar to those affecting the general dog population presented for primary veterinary care in the UK. However, cardiac disease (and MVD in particular) continues to be of particular concern in this breed

Comparison of High-Intensity vs. High-Volume Resistance Training on the BDNF Response to Exercise

This study compared the acute and chronic response of circulating plasma brain-derived neurotrophic factor (BDNF) to high-intensity low-volume (HI) and low-intensity high volume (HV) resistance training. Twenty experienced resistance-trained men (23.5 ± 2.6 y, 1.79 ± 0.05 m, 75.7 ± 13.8 kg) volunteered for this study. Before the resistance training program (PRE), participants performed an acute bout of exercise using either the HI [3-5 reps; 90% of one repetition maximum (1RM)] or HV (10–12 reps; 70% 1RM) training paradigm. The acute exercise protocol was repeated after 7 wk of training (POST). Blood samples were obtained at rest (BL), immediately (IP), 30 min (30P), and 60 min (60P) post exercise at PRE and POST. A three-way repeated measure ANOVA was used to analyze acute changes in BDNF concentrations during HI and HV resistance exercise and the effect of 7 wk of training. No training × time × group interaction in BDNF was noted (P = 0.994). Significant main effects for training (P = 0.050) and time (P \u3c 0.001) in BDNF were observed. Significant elevations in BDNF concentrations were seen from BL at IP (P = 0.001), 30P (P \u3c 0.001), and 60P (P \u3c 0.001) in both HI and HV combined during PRE and POST. BDNF concentrations were also observed to increase from PRE to POST when collapsed across groups and time. No significant group × training interaction (P = 0.342), training (P = 0.105), or group (P = 0.238) effect were noted in the BDNF area under the curve response. Results indicate that BDNF concentrations are increased after an acute bout of resistance exercise, regardless of training paradigm, and are further increased during a 7-wk training program in experienced lifters

A mapping approach to synchronization in the "Zajfman trap": stability conditions and the synchronization mechanism

We present a two particle model to explain the mechanism that stabilizes a bunch of positively charged ions in an "ion trap resonator" [Pedersen etal, Phys. Rev. Lett. 87 (2001) 055001]. The model decomposes the motion of the two ions into two mappings for the free motion in different parts of the trap and one for a compressing momentum kick. The ions' interaction is modelled by a time delay, which then changes the balance between adjacent momentum kicks. Through these mappings we identify the microscopic process that is responsible for synchronization and give the conditions for that regime.Comment: 12 pages, 9 figures; submitted to Phys Rev

Approaches to canine health surveillance

Effective canine health surveillance systems can be used to monitor disease in the general population, prioritise disorders for strategic control and focus clinical research, and to evaluate the success of these measures. The key attributes for optimal data collection systems that support canine disease surveillance are representativeness of the general population, validity of disorder data and sustainability. Limitations in these areas present as selection bias, misclassification bias and discontinuation of the system respectively. Canine health data sources are reviewed to identify their strengths and weaknesses for supporting effective canine health surveillance. Insurance data benefit from large and well-defined denominator populations but are limited by selection bias relating to the clinical events claimed and animals covered. Veterinary referral clinical data offer good reliability for diagnoses but are limited by referral bias for the disorders and animals included. Primary-care practice data have the advantage of excellent representation of the general dog population and recording at the point of care by veterinary professionals but may encounter misclassification problems and technical difficulties related to management and analysis of large datasets. Questionnaire surveys offer speed and low cost but may suffer from low response rates, poor data validation, recall bias and ill-defined denominator population information. Canine health scheme data benefit from well-characterised disorder and animal data but reflect selection bias during the voluntary submissions process. Formal UK passive surveillance systems are limited by chronic under-reporting and selection bias. It is concluded that active collection systems using secondary health data provide the optimal resource for canine health surveillance

Silk from Crickets: A New Twist on Spinning

Raspy crickets (Orthoptera: Gryllacrididae) are unique among the orthopterans in producing silk, which is used to build shelters. This work studied the material composition and the fabrication of cricket silk for the first time. We examined silk-webs produced in captivity, which comprised cylindrical fibers and flat films. Spectra obtained from micro-Raman experiments indicated that the silk is composed of protein, primarily in a beta-sheet conformation, and that fibers and films are almost identical in terms of amino acid composition and secondary structure. The primary sequences of four silk proteins were identified through a mass spectrometry/cDNA library approach. The most abundant silk protein was large in size (300 and 220 kDa variants), rich in alanine, glycine and serine, and contained repetitive sequence motifs; these are features which are shared with several known beta-sheet forming silk proteins. Convergent evolution at the molecular level contrasts with development by crickets of a novel mechanism for silk fabrication. After secretion of cricket silk proteins by the labial glands they are fabricated into mature silk by the labium-hypopharynx, which is modified to allow the controlled formation of either fibers or films. Protein folding into beta-sheet structure during silk fabrication is not driven by shear forces, as is reported for other silks

An epidemiological study of diabetes mellitus in dogs attending first opinion practice in the UK

Objectives: To estimate the prevalence of canine diabetes mellitus (DM) in primarycare clinics in England, to identify risk factors associated with DM and to describe the survival of affected dogs. Methods: Cases of DM were identified within the electronic patient records of 89 small-animal practices. A nested case-control study identified risk factors for the diagnosis of DM using logistic regression models. Cox proportional hazards models were used to analyse variables associated with survival. Results: Four-hundred and thirty-nine canine DM cases were identified, giving an apparent prevalence of 0.34% (95% confidence interval 0.31 - 0.37%). Neutered males were at an increased risk of diabetes compared to entire males, whereas neutering was not associated with DM in females. Compared with crossbred dogs, Yorkshire terriers had increased odds, whereas German shepherd dogs and golden retrievers had lower odds of DM. Being classified as overweight and having a diagnosis of pancreatitis, hyperadrenocorticism or a urinary tract infection were positively associated with DM. Older dogs and those diagnosed with pancreatitis had a higher hazard of death, whereas insured and neutered dogs had a lower hazard. Clinical significance: This study provides an objective assessment of canine DM using primary-care veterinary practice data and is a valuable benchmark against which future epidemiological trends in DM can be assessed and improvements in the management of DM in primary-care practice can be judged