2,018 research outputs found
Daily Sleep Quality is Associated with Daily Cognition in Late-Life
Background: Older adults often face sleep disturbance or cognitive decline that goes beyond the scope of normal aging. The present study examined the relationship between self-reported sleep quality and self-reported daytime attention in a community-dwelling sample of older men at the between-persons and within-persons levels of association.
Methods: Thirty-eight participants (M age =75.36 years, SD age =7.51 years, range=66-90 years) completed a twice-daily sleep diary for one week. Sleep quality and attention were assessed using a single-item 0-10 rating scales from the morning diary (“How was the quality of your sleep last night?”) and from the evening diary (“How was your attention today?”). A two-level multilevel model was parameterized with days nested within individuals to examine whether nightly sleep quality predicts an individual’s daily attention rating.
Results: A multilevel model predicting self-reported attention revealed (1) older individuals who reported better sleep quality reported having better daily attention [Beta=0.64, t(248.15)=10.12, p\u3c0.001] and (2) following a day of above-average sleep quality, older individuals experienced above-average attention [Beta=0.16, t(259.79)=2.75, p=.006].
Conclusion: Not only was overall sleep quality associated with self-reported attention, but a good night\u27s sleep was associated with better self-reported next-day attention. Results point to the potential importance of fluctuations in sleep quality for daytime functioning. Interventions aimed at improving nightly sleep consistency may be worth exploring as methods to improve daytime cognitive functioning in older adults.
Support: This work was supported by the Sleep Research Society Foundation/Jazz Pharmaceuticals (001JP13, PI: Dzierzewski) and by the National Institute on Aging of the National Institutes of Health under Award Number K23AG049955 (PI: Dzierzewski), and National Heart Lung and Blood Institute at the National Institutes of Health under award number K24HL143055 (PI: Martin). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or the Department of Veterans Affairs.https://scholarscompass.vcu.edu/gradposters/1089/thumbnail.jp
Contributions of VLDLR and LRP8 in the establishment of retinogeniculate projections
Background
Retinal ganglion cells (RGCs), the output neurons of the retina, project to over 20 distinct brain nuclei, including the lateral geniculate nucleus (LGN), a thalamic region comprised of three functionally distinct subnuclei: the ventral LGN (vLGN), the dorsal LGN (dLGN) and the intergeniculate leaflet (IGL). We previously identified reelin, an extracellular glycoprotein, as a critical factor that directs class-specific targeting of these subnuclei. Reelin is known to bind to two receptors: very-low-density lipoprotein receptor (VLDLR) and low-density lipoprotein receptor-related protein 8 (LRP8), also known as apolipoprotein E receptor 2 (ApoER2). Here we examined the roles of these canonical reelin receptors in retinogeniculate targeting. Results
To assess the roles of VLDLR and LRP8 in retinogeniculate targeting, we used intraocular injections of fluorescently conjugated cholera toxin B subunit (CTB) to label all RGC axons in vivo. Retinogeniculate projections in mutant mice lacking either VLDLR or LRP8 appeared similar to controls; however, deletion of both receptors resulted in dramatic defects in the pattern of retinal innervation in LGN. Surprisingly, defects in vldlr−/−;lrp8−/− double mutant mice were remarkably different than those observed in mice lacking reelin. First, we failed to observe retinal axons exiting the medial border of the vLGN and IGL to invade distant regions of non-retino-recipient thalamus. Second, an ectopic region of binocular innervation emerged in the dorsomedial pole of vldlr−/−;lrp8−/− mutant dLGN. Analysis of retinal projection development, retinal terminal sizes and LGN cytoarchitecture in vldlr−/−;lrp8−/− mutants, all suggest that a subset of retinal axons destined for the IGL are misrouted to the dorsomedial pole of dLGN in the absence of VLDLR and LRP8. Such mistargeting is likely the result of abnormal migration of IGL neurons into the dorsomedial pole of dLGN in vldlr−/−;lrp8−/− mutants. Conclusions
In contrast to our expectations, the development of both the LGN and retinogeniculate projections appeared dramatically different in mutants lacking either reelin or both canonical reelin receptors. These results suggest that there are reelin-independent functions of VLDLR and LRP8 in LGN development, and VLDLR- and LRP8-independent functions of reelin in class-specific axonal targeting
Pastoralist Use of Reseeded Fields for Additional Resilience to Climate Variability through Alternate Livelihood Activities
Land degradation, climate variability, socio-economic changes and population increase are some of the factors that shrink grazing lands making forage availability less predictable and affecting the resilience of pastoralists communities. Reseeding as an intervention can rehabilitate degraded lands for profitable use through offering pastoralists alternative sources of livelihood and encourage livelihood diversification. This study evaluated two pastoral communities, the Tugen and the Njemps from Baringo County, Kenya, who have owned, managed and used reseeded fields to study the dynamics of reseeding land. A total of 193 pastoralist households were interviewed. These two pastoral communities used their fields for: dry season grazing, grass seed harvesting, cutting thatching grass, milking of mostly cattle, engaging in fattening programs, bailing of hay, and leasing of land. On average, each household engaged in two to three activities with a maximum of five activities combined. The most common activity was dry season grazing which is practiced by 82% of the respondents followed by grass seed harvesting. These activities can be performed in sequence but proper planning is required to ensure that the field remains sustainably productive and successful. Reseeding appears to have high potential for implementation in other dry land counties of Kenya and Sub-Saharan Africa as an intervention that can improve resilience to climate variability as it provides additional grazing ground for the livestock
Effect of psychosocial factors on low back pain in industrial workers
Aim: To test the hypothesis that workplace psychosocial factors such as demand, control, support, job satisfaction and job appreciation can predict the future onset of disabling low back pain (LBP). Methods: The present study involved a prospective cohort of 4500 Iranian industrial workers. Data were gathered by means of a self-reported questionnaire about LBP, as well as working life exposure, lifestyle factors, social exposures, co-morbidity, life events and psychosomatic complaints in 2004. All new episodes of disabling LBP resulting in medically certified sick leave during the 1-year follow-up registered by occupational health clinic inside the factory. Results: The participation rate was good (85). A total of 744 subjects reported current LBP (point prevalence cases). A total of 52 (<2) new episodes of disabling LBP were observed during the 1-year follow-up (incident cases). Male employees reported higher demands, lower control and lower support than female employees. Employees with high demands, low control, job strain, low job satisfaction and low job appreciation showed increased odds ratios, and these results were statistically significant. Conclusions: Few prospective studies in this field have been published, but all of them are related to industrialized countries. This prospective study suggests the aetiological role of job strain for LBP. The findings of this study indicate a substantial potential for disease prevention and health promotion at the workplace. © The Author 2008. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved
Universal point contact resistance between thin-film superconductors
A system comprising two superconducting thin films connected by a point
contact is considered. The contact resistance is calculated as a function of
temperature and film geometry, and is found to vanish rapidly with temperature,
according to a universal, nearly activated form, becoming strictly zero only at
zero temperature. At the lowest temperatures, the activation barrier is set
primarily by the superfluid stiffness in the films, and displays only a weak
(i.e., logarithmic) temperature dependence. The Josephson effect is thus
destroyed, albeit only weakly, as a consequence of the power-law-correlated
superconducting fluctuations present in the films below the
Berezinskii-Kosterlitz-Thouless transition temperature. The behavior of the
resistance is discussed, both in various limiting regimes and as it crosses
over between these regimes. Details are presented of a minimal model of the
films and the contact, and of the calculation of the resistance. A formulation
in terms of quantum phase-slip events is employed, which is natural and
effective in the limit of a good contact. However, it is also shown to be
effective even when the contact is poor and is, indeed, indispensable, as the
system always behaves as if it were in the good-contact limit at low enough
temperature. A simple mechanical analogy is introduced to provide some
heuristic understanding of the nearly-activated temperature dependence of the
resistance. Prospects for experimental tests of the predicted behavior are
discussed, and numerical estimates relevant to anticipated experimental
settings are provided.Comment: 29 pages (single column format), 7 figure
Collective Excitations of Bose-Einstein Condensates in a Double-Well Potential
We investigate collective excitations of Bose-Einstein condensates at
absolute zero in a double-well trap. We solve the Bogoliubov equations with a
double-well trap, and show that the crossover from the dipole mode to the
Josephson plasma mode occurs in the lowest energy excitation. It is found that
the anomalous tunneling property of low energy excitations is crucial to the
crossover.Comment: 14 pages, 6 figure
Macroscopic Symmetry Group Describes Josephson Tunneling in Twinned Crystals
A macroscopic symmetry group describing the superconducting state of an
orthorhombically twinned crystal of YBCO is introduced. This macroscopic
symmetry group is different for different symmetries of twin boundaries.
Josephson tunneling experiments performed on twinned crystals of YBCO determine
this macroscopic symmetry group and hence determine the twin boundary symmetry
(but do not experimentally determine whether the microscopic order parameter is
primarily d- or s-wave). A consequence of the odd-symmetry twin boundaries in
YBCO is the stability of vortices containing one half an elementary flux
quantum at the intersection of a twin boundary and certain grain boundaries.Comment: 6 pages, to be published in the Proceedings of the MOS96 Conference
in the Journal of Low Temperature Physic
Universal amplitude ratios from numerical studies of the three-dimensional O(2) model
We investigate the three-dimensional O(2) model near the critical point by
Monte Carlo simulations and calculate the major universal amplitude ratios of
the model. The ratio U_0=A+/A- is determined directly from the specific heat
data at zero magnetic field. The data do not, however, allow to extract an
accurate estimate for alpha. Instead, we establish a strong correlation of U_0
with the value of alpha used in the fit. This numerical alpha-dependence is
given by A+/A- = 1 -4.20(5) alpha + O(alpha^2). For the special alpha-values
used in other calculations we find full agreement with the corresponding ratio
values, e. g. that of the shuttle experiment with liquid helium. On the
critical isochore we obtain the ratio xi+/xi-_T=0.293(9), and on the critical
line the ratio xi_T^c/xi_L^c=1.957(10) for the amplitudes of the transverse and
longitudinal correlation lengths. These two ratios are independent of the used
alpha or nu-values.Comment: 34 pages, 19 Ps-figures, Latex2e, revised version, to be published in
J. Phys.
Administration of a Glycoprotein IIb/IIIa Receptor Blocker with a Thienopyridine Derivative Does Not Increase the Risk of Thrombocytopenia
Author Institution: Akron Cardiology Consulltants, OHAuthor Institution: Dept. of Educational Foundations & Leadership, University of Akron, OHAuthor Institution: Summa Health System, University of Akron, OHAuthor Institution: Dept. of Medicine, Northeast Ohio Universities College of Medicine, Rootstown, OHAuthor Institution: Cardiac Rehabilitation Institute, Summa Health Syste, University of Akron, OHThe combination of aspirin, a thienopyridine derivative, and a glycoprotein IIb/IIIa receptor inhibitor has become standard therapy for patients undergoing percutaneous coronary intervention (PCI). Recent studies have shown an increased incidence of thrombocytopenia in those patients receiving a high loading dose of clopidogrel (thienopyridine) with abciximab (IIb/IIIa receptor inhibitor) prior to coronary intervention. We reviewed the records of 504 patients who underwent PCI at a large tertiary care hospital and noted an incidence of thrombocytopenia of 4.8%, comparable to published historical controls who received abciximab without clopidogrel. In patients undergoing PCI, there was no difference in thrombocytopenia or bleeding complications between patients receiving a high or a low dose of a thienopyridine. We conclude that a high loading dose of a thienopyridine derivative prior to PCI may
be administered safely and efficaciously in the setting of concomitant administration of abciximab without an undue risk of thrombocytopenia
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