193 research outputs found
A New Microlensing Event in the Doubly-Imaged Quasar Q0957+561
We present evidence for ultraviolet/optical microlensing in the
gravitationally lensed quasar Q0957+561. We combine new measurements from our
optical monitoring campaign at the United States Naval Observatory, Flagstaff
(USNO) with measurements from the literature and find that the
time-delay-corrected r-band flux ratio m_A - m_B has increased by ~0.1
magnitudes over a period of five years beginning in the fall of 2005. We apply
our Monte Carlo microlensing analysis procedure to the composite light curves,
obtaining a measurement of the optical accretion disk size, log
{(r_s/cm)[cos(i)/0.5]^{1/2}} = 16.2^{+0.5}_{-0.6}, that is consistent with the
quasar accretion disk size - black hole mass relation.Comment: Replaced with accepted version. Minor adjustments to text but
conclusions unchanged. Data in Table 2 have been updated and table now
includes additional observation
The Sun Health Research Institute Brain Donation Program: Description and Eexperience, 1987–2007
The Brain Donation Program at Sun Health Research Institute has been in continual operation since 1987, with over 1000 brains banked. The population studied primarily resides in the retirement communities of northwest metropolitan Phoenix, Arizona. The Institute is affiliated with Sun Health, a nonprofit community-owned and operated health care provider. Subjects are enrolled prospectively to allow standardized clinical assessments during life. Funding comes primarily from competitive grants. The Program has made short postmortem brain retrieval a priority, with a 2.75-h median postmortem interval for the entire collection. This maximizes the utility of the resource for molecular studies; frozen tissue from approximately 82% of all cases is suitable for RNA studies. Studies performed in-house have shown that, even with very short postmortem intervals, increasing delays in brain retrieval adversely affect RNA integrity and that cerebrospinal fluid pH increases with postmortem interval but does not predict tissue viability
Pairing fluctuations and pseudogaps in the attractive Hubbard model
The two-dimensional attractive Hubbard model is studied in the weak to
intermediate coupling regime by employing a non-perturbative approach. It is
first shown that this approach is in quantitative agreement with Monte Carlo
calculations for both single-particle and two-particle quantities. Both the
density of states and the single-particle spectral weight show a pseudogap at
the Fermi energy below some characteristic temperature T*, also in good
agreement with quantum Monte Carlo calculations. The pseudogap is caused by
critical pairing fluctuations in the low-temperature renormalized classical
regime of the two-dimensional system. With increasing temperature
the spectral weight fills in the pseudogap instead of closing it and the
pseudogap appears earlier in the density of states than in the spectral
function. Small temperature changes around T* can modify the spectral weight
over frequency scales much larger than temperature. Several qualitative results
for the s-wave case should remain true for d-wave superconductors.Comment: 20 pages, 12 figure
Protocol of a randomized controlled trial of an erythropoietin stimulating agent decision aid for anemia treatment in kidney disease
Recommended from our members
Women’s experiences of decision-making and informed choice about pregnancy and birth care: a systematic review and meta-synthesis of qualitative research
Background
The purpose of this systematic review (PROSPERO Ref: CRD42017053264) was to describe and interpret the qualitative research on parent’s decision-making and informed choice about their pregnancy and birth care. Given the growing evidence on the benefits of different models of maternity care and the prominence of informed choice in health policy, the review aimed to shed light on the research to date and what the findings indicate.
Methods
a systematic search and screening of qualitative research concerning parents’ decision-making and informed choice experiences about pregnancy and birth care was conducted using PRISMA guidelines. A meta-synthesis approach was taken for the extraction and analysis of data and generation of the findings. Studies from 1990s onwards were included to reflect an era of policies promoting choice in maternity care in high-income countries.
Results
Thirty-seven original studies were included in the review. A multi-dimensional conceptual framework was developed, consisting of three analytical themes (‘Uncertainty’, ‘Bodily autonomy and integrity’ and ‘Performing good motherhood’) and three inter-linking actions (‘Information gathering,’ ‘Aligning with a birth philosophy,’ and ‘Balancing aspects of a choice’).
Conclusions
Despite the increasing research on decision-making, informed choice is not often a primary research aim, and its development in literature published since the 1990s was difficult to ascertain. The meta-synthesis suggests that decision-making is a dynamic and temporal process, in that it is made within a defined period and invokes both the past, whether this is personal, familial, social or historical, and the future. Our findings also highlighted the importance of embodiment in maternal health experiences, particularly when it comes to decision-making about care. Policymakers and practitioners alike should examine critically current choice frameworks to ascertain whether they truly allow for flexibility in decision-making. Health systems should embrace more fluid, personalised models of care to augment service users’ decision-making agency
Speech Communication
Contains table of contents for Part IV, table of contents for Section 1, an introduction, reports on seven research projects and a list of publications.C.J. Lebel FellowshipDennis Klatt Memorial FundNational Institutes of Health Grant T32-DC00005National Institutes of Health Grant R01-DC00075National Institutes of Health Grant F32-DC00015National Institutes of Health Grant R01-DC00266National Institutes of Health Grant P01-DC00361National Institutes of Health Grant R01-DC00776National Science Foundation Grant IRI 89-10561National Science Foundation Grant IRI 88-05680National Science Foundation Grant INT 90-2471
The immune system and the impact of zinc during aging
The trace element zinc is essential for the immune system, and zinc deficiency affects multiple aspects of innate and adaptive immunity. There are remarkable parallels in the immunological changes during aging and zinc deficiency, including a reduction in the activity of the thymus and thymic hormones, a shift of the T helper cell balance toward T helper type 2 cells, decreased response to vaccination, and impaired functions of innate immune cells. Many studies confirm a decline of zinc levels with age. Most of these studies do not classify the majority of elderly as zinc deficient, but even marginal zinc deprivation can affect immune function. Consequently, oral zinc supplementation demonstrates the potential to improve immunity and efficiently downregulates chronic inflammatory responses in the elderly. These data indicate that a wide prevalence of marginal zinc deficiency in elderly people may contribute to immunosenescence
Recommended from our members
Common genetic variants in the CLDN2 and PRSS1-PRSS2 loci alter risk for alcohol-related and sporadic pancreatitis
Pancreatitis is a complex, progressively destructive inflammatory disorder. Alcohol was long thought to be the primary causative agent, but genetic contributions have been of interest since the discovery that rare PRSS1, CFTR, and SPINK1 variants were associated with pancreatitis risk. We now report two significant genome-wide associations identified and replicated at PRSS1-PRSS2 (1×10-12) and x-linked CLDN2 (p < 1×10-21) through a two-stage genome-wide study (Stage 1, 676 cases and 4507 controls; Stage 2, 910 cases and 4170 controls). The PRSS1 variant affects susceptibility by altering expression of the primary trypsinogen gene. The CLDN2 risk allele is associated with atypical localization of claudin-2 in pancreatic acinar cells. The homozygous (or hemizygous male) CLDN2 genotype confers the greatest risk, and its alleles interact with alcohol consumption to amplify risk. These results could partially explain the high frequency of alcohol-related pancreatitis in men – male hemizygous frequency is 0.26, female homozygote is 0.07
- …