1,016,140 research outputs found
Social, environmental and psychological factors associated with objective physical activity levels in the over 65s
Objective: To assess physical activity levels objectively using accelerometers in community dwelling over 65 s and to examine associations with health, social, environmental and psychological factors. Design: Cross sectional survey. Setting: 17 general practices in Scotland, United Kingdom. Participants: Random sampling of over 65 s registered with the practices in four strata young-old (65–80 years), old-old (over 80 years), more affluent and less affluent groups. Main Outcome Measures: Accelerometry counts of activity per day. Associations between activity and Theory of Planned Behaviour variables, the physical environment, health, wellbeing and demographic variables were examined with multiple regression analysis and multilevel modelling. Results: 547 older people (mean (SD) age 79(8) years, 54% female) were analysed representing 94% of those surveyed. Accelerometry counts were highest in the affluent younger group, followed by the deprived younger group, with lowest levels in the deprived over 80 s group. Multiple regression analysis showed that lower age, higher perceived behavioural control, the physical function subscale of SF-36, and having someone nearby to turn to were all independently associated with higher physical activity levels (R2 = 0.32). In addition, hours of sunshine were independently significantly associated with greater physical activity in a multilevel model. Conclusions: Other than age and hours of sunlight, the variables identified are modifiable, and provide a strong basis for the future development of novel multidimensional interventions aimed at increasing activity participation in later life.Peer reviewe
Indices of adrenal cortical activity in men exposed to cold
Thesis (M.A.)--Boston UniversityEvidence of physiological acclimatization of man to cold is scanty and not clear-cut. Certainly no adaptations have been described comparable to the dramatic changes which occur when men are acclimatized to heat. This study is an attempt to demonstrate acclimatization to cold in man, not in terms of indices specific for cold stress, but rather by measurement of the systemic strain placed on the body. Experiments were designed to answer two questions: (a) Does cold exposure result in a systemic strain on the body? and (b) Does continued cold exposure give rise to (unknown) specific physiologic a aptations with a consequent reduced strain? Since stimulation of tne pituitary-adrenal cortical axis seems to be a common denominator in all known stress situations, adrenal cortical activity was used as a measure of the degree of distortion to the homeostasis.
The following experimental design was used: Twelve young soldiers previously brought into good physical condition by mild exercise were exposed to the following successive sets of conditions: four weeks of no cold exposure (baseline period) during which control measurements were made; twelve consecutive days of continuous cold exposure at 60°F.; nine days of no cold exposure; five days of re-exposure to cold (60°F.); five days of no cold exposure. Adrenal cortical activity was assessed by means of circulating eosinophil counts and urinary uric acid: creatinine ratios. During cold exposure periods the men remained continuously in the cold room, leaving it only for meals, bathing and control procedures (a total of 4 1/4 hours daily). They reclined nude except for cotton shorts on army beds from 8:00 A.M. till noon and from 1:15 P.M. till 4:30 P.M. In order to obtain comparable conditions throughout all experimental periods for the assessment of basal levels of adrenal cortical activity, the men lay quietly from 7:00- 8:00A.M. in a constant temperature room maintained at 85°F.
+/- 1°F.; at the end of this hour, urine was collected and blood drawn. These samples also served as controls for the measurement of acute responses after four hours in the cold.
Sixty degrees Fahrenheit was selected as the cold temperature because it eliminated the danger of cold injury, making it unnecessary to rewarm the men periodically or to clothe them. It was deemed an adequate stimulus because men exhibit the usual cold responses at this temperature - shivering, diuresis, hemoconcentration and peripheral vasoconstriction - within 45 minutes to two hours after the start of exposure. Furthermore preliminary experiments showed this temperature to produce marked discomfort which, however, was tolerable for prolonged periods.
The following results were obtained:
1. There was a significant depression of basal eosinophil counts on the fourth and eighth days of the first cold period, with a return to approximately control levels on the eleventh day.
2. A "rebound" of basal eosinophil counts to levels significantly above controls was observed in the nine-day period between cold exposures.
3. Eosinophil counts taken on the fourth day of re-exposure were not significantly different from controls, but were significantly below "rebound" values.
4. No marked differences from normal diurnal variation were observed in the eosinophil counts after four hours of cold exposure at 60°F.
5. No trends were observed in basal uric acid: creatinine ratios.
6. During acute four-hour exposure, uric acid: creatinine ratios were significantly higher than controls. Although no correlation existed between eosinophil and (U-A)/C changes, there was a significant correlation between rate of urine flow and (U-A)/C.
Although both eosinophil counts and uric acid: creatinine ratios are preserved to measure activity related to 11-oxygenated corticosteroids, the results show a qualitative difference between the two indices. The eosinophil data indicate changes in basal activity but no marked response to acute exposure, whereas the (U-A)/C data suggest acute responses but no change in basal levels. This confirms the findings of previous workers of a lack of parallelism between these indices in conditions of mild stress.
The changes in basal eosinophil counts suggest positive findings of acclimatization to cold. The significant decreases on the fourth and eighth days of exposure indicate increased adrenal cortical activity; the return toward pre-exposure levels on the eleventh day suggest a return of activity toward normal. These results are consistent with, but do not prove, the thesis that cold exposure under the conditions described results in a systemic strain on the body, and that the strain is lessened on extended exposure. This suggests that physiological acclimatization to cold occurs. These conclusions are based on assumptions that (a) changes in circulating eosinophil counts reflect changes in adrenal cortical activity and (b) changes in such activity are a measure of the severity of strain placed on the body
Physicochemical and microbiological characteristics of kitoza, a traditional salted/dried/smoked meat product of Madagascar
Kitoza samples collected from producers in Madagascar were analyzed for their physicochemical and microbial properties. Lactic acid bacteria and coagulase‐negative staphylococci were the two codominant populations with average counts of 6–7 log cfu/g. Good hygienic practices were sometimes lacking but samples were not contaminated with Salmonella, Clostridium perfringens, and Bacillus cereus and only once with Listeria monocytogenes. Staphylococcus aureus was found occasionally with higher counts in salted/dried products than in salted/smoked products. Moisture, protein, fat, and salt contents varied considerably and were on average 41.5, 43.5, 14.3, and 3.3 g/100 g, respectively, and water activity was 0.893 on average. Smoked kitoza showed higher moisture content compared to dried kitoza. Most of the smoked kitoza had a water activity higher than 0.9 which is not in accordance with their storage at ambient temperatures. Benzo(a)pyrene content was above 2 µg/kg in 11 out of 30 smoked samples (17 ± 16.5 µg/kg on average)
Genetic variation among lambs in peripheral IgE activity against the larval stages of <i>Teladorsagia circumcincta</i>
IgA and IgE activity against Teladorsagia circumcincta was investigated in a flock of Texel lambs following natural, mixed nematode infection among lambs. The distribution of IgA activity was similar to a gamma distribution whereas IgE activity was different. Box-Cox analysis demonstrated that X0.25 was a suitable transformation to normalise IgE responses. The transformed IgE activity was under moderate to strong genetic control. Nine different allergens were identified by proteomic analysis. Tropomyosin was selected for further analysis. IgE activity against tropomyosin was moderately heritable and associated with decreased egg counts and with reduced body weight at the time of sampling
Effect of a pre-milking teat foam and a liner disinfectant on the presence of mesophilic and (proteolytic) psychrotrophic bacteria prior to milking
Contamination of raw milk by psychrotrophs can lead to the production of heat-resistant proteases and subsequent spoilage of UHT milk. Therefore, this research communication evaluated the effect of a pre-milking teat disinfectant (active components: L-(+)-lactic acid and salicylic acid) and a liner disinfectant (active components: peracetic acid and hydrogen peroxide) on the number of mesophilic and (proteolytic) psychrotrophic bacteria prior to milking. The teat orifices of 10 cows were sampled using a swabbing procedure before and after treatment with a pre-milking teat disinfectant on six subsequent days. On the teat orifices, there was a small but statistically significant decrease in the psychrotrophic bacterial counts between pre and post dipping. No differences were observed for the mesophilic bacterial counts and proteolytic active counts. Liners were also sampled using swabs pre and post disinfection. No statistically significant decrease in the bacterial counts was observed post liner disinfection, although there was a numerical decrease. Sixty-two percent of the proteolytic psychrotrophs were pseudomonads: 16.5% of which were P. fragi, 14.3% P. lundensis, 10.0% P. fluorescens and 2.9% P. putida. Trinitrobenzenesulfonic acid (TNBS) analysis revealed a wide variety in proteolytic activity (from 0 to 55 mu mol glycine/ml milk) and the presence of high producers. It can be concluded that there was only a minor effect of teat and liner disinfection on the psychrotrophic bacterial counts indicating that the measures presented did not result in a reduction of the targeted bacteria on teat orifices and liners
Calibrating the Galaxy Halo - Black Hole Relation Based on the Clustering of Quasars
The observed number counts of quasars may be explained either by long-lived
activity within rare massive hosts, or by short-lived activity within smaller,
more common hosts. It has been argued that quasar lifetimes may therefore be
inferred from their clustering length, which determines the typical mass of the
quasar host. Here we point out that the relationship between the mass of the
black-hole and the circular velocity of its host dark-matter halo is more
fundamental to the determination of the clustering length. In particular, the
clustering length observed in the 2dF quasar redshift survey is consistent with
the galactic halo - black-hole relation observed in local galaxies, provided
that quasars shine at ~10-100% of their Eddington luminosity. The slow
evolution of the clustering length with redshift inferred in the 2dF quasar
survey favors a black-hole mass whose redshift-independent scaling is with halo
circular velocity, rather than halo mass. These results are independent from
observations of the number counts of bright quasars which may be used to
determine the quasar lifetime and its dependence on redshift. We show that if
quasar activity results from galaxy mergers, then the number counts of quasars
imply an episodic quasar lifetime that is set by the dynamical time of the host
galaxy rather than by the Salpeter time. Our results imply that as the redshift
increases, the central black-holes comprise a larger fraction of their host
galaxy mass and the quasar lifetime gets shorter.Comment: 10 pages, 5 figures. Submitted to Ap
Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.
BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities ≥500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity ≥500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500
Assessment of detectability of neutral interstellar deuterium by IBEX observations
The abundance of deuterium in the interstellar gas in front of the Sun gives
insight into the processes of filtration of neutral interstellar species
through the heliospheric interface and potentially into the chemical evolution
of the Galactic gas. We investigate the possibility of detection of neutral
interstellar deuterium at 1 AU from the Sun by direct sampling by the
Interstellar Boundary Explorer (IBEX). We simulate the flux of neutral
interstellar D at IBEX for the actual measurement conditions. We assess the
number of interstellar D atom counts expected during the first three years of
IBEX operation. We also simulate observations expected during an epoch of high
solar activity. In addition, we calculate the expected counts of D atoms from
the thin terrestrial water layer, sputtered from the IBEX-Lo conversion surface
by neutral interstellar He atoms. Most D counts registered by IBEX-Lo are
expected to originate from the water layer, exceeding the interstellar signal
by 2 orders of magnitude. However, the sputtering should stop once the Earth
leaves the portion of orbit traversed by interstellar He atoms. We identify
seasons during the year when mostly the genuine interstellar D atoms are
expected in the signal. During the first 3 years of IBEX operations about 2
detectable interstellar D atoms are expected. This number is comparable with
the expected number of sputtered D atoms registered during the same time
intervals. The most favorable conditions for the detection occur during low
solar activity, in an interval including March and April each year. The
detection chances could be improved by extending the instrument duty cycle,
e.g., by making observations in the special deuterium mode of IBEX-Lo.Comment: Accepted for Astronomy & Astrophysic
DAS28: a useful instrument to monitor infliximab treatment in patients with rheumatoid arthritis
The Disease Activity Score using 28 joint counts (DAS28) has been developed in a cohort of patients with rheumatoid arthritis in which only conventional anti-rheumatic treatments were used. It has extensively been validated to monitor disease activity in daily clinical practice as well as in clinical trials. The study of Vander Cruyssen and colleagues showed that the DAS28 correlated best with the decisions of rheumatologists to increase the infliximab dose because of insufficient response. This result once more confirms the validity of the DAS28 to monitor disease activity in patients with rheumatoid arthritis and to titrate treatment with biologicals
- …
