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An observational account of research carried out in July-August 1999 shows that grounded iceberg and related fast-ice distributions, and periodic "break-outs" of fast ice (in winter as well as at other times), have an important impact on the size and behaviour of the Mertz Glacier polynya, East Antarctica, and a smaller polynya to the east. Analysis of satellite and in situ data shows that a semi-constant "stream" of thick broken-out fast ice and other large floes from the east extends westwards from north of the glacier terminus to form a compact barrier to the net west-northwesterly export of ice formed in the polynya. An annual fast-ice promontory to the west further narrows the outlet path. As a result of this and high ice-production rates, the polynya periodically "back-fills", significantly reducing the open-water area present. Intervening "flush-outs" by synoptic storm events clear the polynya region to some extent before it back-fills again. This cycle continued from mid-March until early October in 1999, when a significant change in the regional ice drift occurred. A preliminary comparison with data from 1998 indicates that the timing and magnitude of the processes may vary interannually. Similar morphological features were also observed in 1963 (on a declassified photoreconnaissance satellite image).
We report progress on a spectroscopic and photometric programme devoted to the study of the dynamics of O-F5 stars within 15° of the North and South Galactic Poles. The aims of the programme are to test dynamical and chemical evolution models of the Galaxy by establishing velocity dispersions as a function of z-distance for stars of different population groups. We are also able to investigate the interstellar reddening at the poles and the kinematic properties of apparently normal early-type stars found more than 1 kpc from the galactic plane.
To determine if total lifetime physical activity (PA) is associated with better cognitive functioning with aging and if cerebrovascular function mediates this association. A sample of 226 (52.2% female) community dwelling middle-aged and older adults (66.5±6.4 years) in the Brain in Motion Study, completed the Lifetime Total Physical Activity Questionnaire and underwent neuropsychological and cerebrovascular blood flow testing. Multiple robust linear regressions were used to model the associations between lifetime PA and global cognition after adjusting for age, sex, North American Adult Reading Test results (i.e., an estimate of premorbid intellectual ability), maximal aerobic capacity, body mass index and interactions between age, sex, and lifetime PA. Mediation analysis assessed the effect of cerebrovascular measures on the association between lifetime PA and global cognition. Post hoc analyses assessed past year PA and current fitness levels relation to global cognition and cerebrovascular measures. Better global cognitive performance was associated with higher lifetime PA (p=.045), recreational PA (p=.021), and vigorous intensity PA (p=.004), PA between the ages of 0 and 20 years (p=.036), and between the ages of 21 and 35 years (p<.0001). Cerebrovascular measures did not mediate the association between PA and global cognition scores (p>.5), but partially mediated the relation between current fitness and global cognition. This study revealed significant associations between higher levels of PA (i.e., total lifetime, recreational, vigorous PA, and past year) and better cognitive function in later life. Current fitness levels relation to cognitive function may be partially mediated through current cerebrovascular function. (JINS, 2015, 21, 816–830)
Considerable research has documented that exposure to traumatic events has negative effects on physical and mental health. Much less research has examined the predictors of traumatic event exposure. Increased understanding of risk factors for exposure to traumatic events could be of considerable value in targeting preventive interventions and anticipating service needs.
General population surveys in 24 countries with a combined sample of 68 894 adult respondents across six continents assessed exposure to 29 traumatic event types. Differences in prevalence were examined with cross-tabulations. Exploratory factor analysis was conducted to determine whether traumatic event types clustered into interpretable factors. Survival analysis was carried out to examine associations of sociodemographic characteristics and prior traumatic events with subsequent exposure.
Over 70% of respondents reported a traumatic event; 30.5% were exposed to four or more. Five types – witnessing death or serious injury, the unexpected death of a loved one, being mugged, being in a life-threatening automobile accident, and experiencing a life-threatening illness or injury – accounted for over half of all exposures. Exposure varied by country, sociodemographics and history of prior traumatic events. Being married was the most consistent protective factor. Exposure to interpersonal violence had the strongest associations with subsequent traumatic events.
Given the near ubiquity of exposure, limited resources may best be dedicated to those that are more likely to be further exposed such as victims of interpersonal violence. Identifying mechanisms that account for the associations of prior interpersonal violence with subsequent trauma is critical to develop interventions to prevent revictimization.
The incidence of recreational water-associated outbreaks in the United States has significantly increased, driven, at least in part, by outbreaks both caused by Cryptosporidium and associated with treated recreational water venues. Because of the parasite's extreme chlorine tolerance, transmission can occur even in well-maintained treated recreational water venues (e.g. pools) and a focal cryptosporidiosis outbreak can evolve into a community-wide outbreak associated with multiple recreational water venues and settings (e.g. childcare facilities). In August 2004 in Auglaize County, Ohio, multiple cryptosporidiosis cases were identified and anecdotally linked to pool A. Within 5 days of the first case being reported, pool A was hyperchlorinated to achieve 99·9% Cryptosporidium inactivition. A case-control study was launched to epidemiologically ascertain the outbreak source 11 days later. A total of 150 confirmed and probable cases were identified; the temporal distribution of illness onset was peaked, indicating a point-source exposure. Cryptosporidiosis was significantly associated with swimming in pool A (matched odds ratio 121·7, 95% confidence interval 27·4–∞) but not with another venue or setting. The findings of this investigation suggest that proactive implementation of control measures, when increased Cryptosporidium transmission is detected but before an outbreak source is epidemiologically ascertained, might prevent a focal cryptosporidiosis outbreak from evolving into a community-wide outbreak.
Incidental findings arising from imaging research have important implications for patient safety. Magnetic resonance imaging is widespread in multiple sclerosis (MS) studies and care, yet the prevalence rate of incidental findings in MS is poorly defined. The absence of such reports in the MS literature suggests that such findings may be deemed inappropriate for documentation in research publications, or possibly, not fully reported at all.
We sought to document incidental findings from a study designed to detect features of chronic cerebrospinal venous insufficiency (CCSVI) in MS patients and control subjects.
Magnetic resonance images were obtained as part of a prospective study conducted between October 2010 and September 2012. Patients with MS (relapsing-remitting, primary progressive, secondary progressive), clinically isolated syndromes, and neuromyelitis optica and age/sex-matched healthy controls were included. All images were reviewed by neuro-radiologists for quality-control purposes.
Magnetic resonance imaging was successfully obtained in 166 participants (110 patients, 56 controls). Incidental abnormalities (n = 33) were detected in 15% of patients (n = 17) and 27% of controls (n = 15), comprising 19% overall (n = 32).
The prevalence of incidental findings from the MS population was not significantly different from the control population. However, the overall prevalence was high and warrants a careful management strategy for future imaging studies.
The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope1, MALT90 has obtained 3′ × 3′ maps towards ~2 000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to
regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38 arcsec) and spectral (0.11 km s−1) resolution, the data reveal a wealth of information about the clumps’ morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high-resolution studies with ALMA.
In June 2011, a cluster of suspected cases of Guillain–Barré syndrome (GBS), which can follow Campylobacter jejuni infection, was identified in San Luis Río Colorado (SLRC), Sonora, Mexico and Yuma County, Arizona, USA. An outbreak investigation identified 26 patients (18 from Sonora, eight from Arizona) with onset of GBS 4 May–21 July 2011, exceeding the expected number of cases (n = 1–2). Twenty-one (81%) patients reported antecedent diarrhoea, and 61% of 18 patients tested were seropositive for C. jejuni IgM antibodies. In a case-control study matched on age group, sex, ethnicity, and neighbourhood of residence, all Arizona GBS patients travelled to SLRC during the exposure period vs. 45% of matched controls (matched odds ratio 8·1, 95% confidence interval 1·5–∞). Exposure information and an environmental assessment suggested that GBS cases resulted from a large outbreak of C. jejuni infection from inadequately disinfected tap water in SLRC. Binational collaboration was essential in investigating this cross-border GBS outbreak, the first in mainland North America since 1976.
Medium to high-resolution stellar spectroscopic surveys can potentially be used to build DIB databases by means of automated methods of analysis. Multiplex spectrographs increase strongly those potentialities and allow small-scale variability studies. Because measurements of the stellar parameters are generally the primary goal of the surveys, synthetic spectra can be computed and used to extract DIBs from late-type star data. Large datasets should allow deeper investigations on the DIB variability in response to stellar radiation fields, DIB reddening relationships, and help localizing interstellar clouds. Here we describe our attempts to build and test automated methods adapted to both early and late type stars.
We have developed a method allowing to extract DIBs from cool star spectra, based on combinations of stellar synthetic, telluric transmission (when necessary), and DIB profile models. It is applicable when the star temperature, surface gravity and metallicity have been previously estimated. Such a method aims at extracting extensive data from stellar spectroscopic surveys such as the Gaia-ESO Survey in progress at the VLT. The method has been applied to several strong DIBs detected towards stars from various programs and located at various distances from the solar neighborhood to the Galactic Bulge. Here we illustrate the extraction of the 8620 Å DIB, and compare its strength to the one of the 6284 Å band, both for nearby and bulge stars.
A survey of the Milky Way disk and the Magellanic System at the wavelengths of the 21-cm atomic hydrogen (H i) line and three 18-cm lines of the OH molecule will be carried out with the Australian Square Kilometre Array Pathfinder telescope. The survey will study the distribution of H i emission and absorption with unprecedented angular and velocity resolution, as well as molecular line thermal emission, absorption, and maser lines. The area to be covered includes the Galactic plane (|b| < 10°) at all declinations south of δ = +40°, spanning longitudes 167° through 360°to 79° at b = 0°, plus the entire area of the Magellanic Stream and Clouds, a total of 13 020 deg2. The brightness temperature sensitivity will be very good, typically σT≃ 1 K at resolution 30 arcsec and 1 km s−1. The survey has a wide spectrum of scientific goals, from studies of galaxy evolution to star formation, with particular contributions to understanding stellar wind kinematics, the thermal phases of the interstellar medium, the interaction between gas in the disk and halo, and the dynamical and thermal states of gas at various positions along the Magellanic Stream.
This investigation reports the synthesis of Ni-ferrite and ZrO2 added Ni-ferrite powdered materials for H2 generation from thermochemical water-splitting reaction. NiFe2O4 was synthesized using sol-gel technique in which salts of Ni and Fe were sonicated in ethanol until a visually clear solution was obtained. To this solution, propylene oxide was added to achieve the gel formation. As-prepared gel was dried at 100oC for 1 h and calcined upto 600oC at a ramp rate of 40oC/min. The calcined sample from the furnace was removed at 600oC and cooled down at room temperature in air. To synthesize NiFe2O4/ZrO2 powdered mixture, ZrO2 nanoparticles were mixed with the calcined ferrite powder using vortex mixer. These powdered materials were analyzed using powder x-ray diffractometer (XRD), BET surface area analyzer and scanning (SEM) and transmission electron microscopy (TEM). As-prepared NiFe2O4 and ZrO2 added NiFe2O4 powdered materials were loaded in an Inconel tubular reactor to investigate H2 generation from four consecutive thermochemical cycles where water-splitting and regeneration was performed at 900o and 1100oC, respectively.
There is evidence of a reduction in children's physical activity in India in the last decade. Our objective was to assess whether size and body composition at birth are associated with physical activity in school-aged children. Children from a prospective observational cohort study born in Mysore, South India between 1997 and 1998 (n = 663) had neonatal anthropometric measurements made within 72 h of delivery [weight, mid-upper arm circumference (MUAC), chest, abdomen and head circumference, crown–heel, crown–buttock and leg length, triceps and subscapular skinfolds]. At 6–10 years, children (n = 449) were asked to wear AM7164 or GT1M Actigraph accelerometers for 7 days. Body composition was measured within 6 months of activity monitoring. Arm muscle area at birth and time of activity monitoring was calculated from MUAC and skinfold measurements.
Activity outcome measures were: mean accelerometer counts per minute (cpm); counts per day and proportion of time spent in moderate and vigorous activity. The mean (s.d.) number of days with ⩾500 min of recorded accelerometer data was 7.0 (1.1). Linear regression models showed no significant associations between any of the neonatal anthropometric measures and the activity variables. Body fat percentage at 7.5 years was negatively associated with all activity variables (B = −4.69, CI: −7.31, −2.07 for mean cpm).
In conclusion, this study showed no associations between body size and skinfold thickness at birth and objectively measured physical activity in childhood.