238 research outputs found
Overcoming real-world obstacles in 21 cm power spectrum estimation: A method demonstration and results from early Murchison Widefield Array data
We present techniques for bridging the gap between idealized inverse covariance weighted quadratic estimation of 21 cm power spectra and the real-world challenges presented universally by interferometric observation. By carefully evaluating various estimators and adapting our techniques for large but incomplete data sets, we develop a robust power spectrum estimation framework that preserves the so-called "Epoch of Reionization (EoR) window" and keeps track of estimator errors and covariances. We apply our method to observations from the 32-tile prototype of the Murchinson Widefield Array to demonstrate the importance of a judicious analysis technique. Lastly, we apply our method to investigate the dependence of the clean EoR window on frequency—especially the frequency dependence of the so-called “wedge" feature—and establish upper limits on the power spectrum from z ¼ 6.2 to z ¼ 11:7. Our lowest limit is ?ðkÞ < 0.3 Kelvin at 95% confidence at a comoving scale k ¼ 0.046 Mpc-1 and z ¼ 9.5
LSST: from Science Drivers to Reference Design and Anticipated Data Products
(Abridged) We describe here the most ambitious survey currently planned in
the optical, the Large Synoptic Survey Telescope (LSST). A vast array of
science will be enabled by a single wide-deep-fast sky survey, and LSST will
have unique survey capability in the faint time domain. The LSST design is
driven by four main science themes: probing dark energy and dark matter, taking
an inventory of the Solar System, exploring the transient optical sky, and
mapping the Milky Way. LSST will be a wide-field ground-based system sited at
Cerro Pach\'{o}n in northern Chile. The telescope will have an 8.4 m (6.5 m
effective) primary mirror, a 9.6 deg field of view, and a 3.2 Gigapixel
camera. The standard observing sequence will consist of pairs of 15-second
exposures in a given field, with two such visits in each pointing in a given
night. With these repeats, the LSST system is capable of imaging about 10,000
square degrees of sky in a single filter in three nights. The typical 5
point-source depth in a single visit in will be (AB). The
project is in the construction phase and will begin regular survey operations
by 2022. The survey area will be contained within 30,000 deg with
, and will be imaged multiple times in six bands, ,
covering the wavelength range 320--1050 nm. About 90\% of the observing time
will be devoted to a deep-wide-fast survey mode which will uniformly observe a
18,000 deg region about 800 times (summed over all six bands) during the
anticipated 10 years of operations, and yield a coadded map to . The
remaining 10\% of the observing time will be allocated to projects such as a
Very Deep and Fast time domain survey. The goal is to make LSST data products,
including a relational database of about 32 trillion observations of 40 billion
objects, available to the public and scientists around the world.Comment: 57 pages, 32 color figures, version with high-resolution figures
available from https://www.lsst.org/overvie
Jak2V617F Reversible Activation Shows Its Essential Requirement in Myeloproliferative Neoplasms
Gain-of-function mutations activating JAK/STAT signaling are seen in the majority of patients with myeloproliferative neoplasms (MPN), most commonly JAK2V617F. Although clinically approved JAK inhibitors improve symptoms and outcomes in MPNs, remissions are rare, and mutant allele burden does not substantively change with chronic therapy. We hypothesized this is due to limitations of current JAK inhibitors to potently and specifically abrogate mutant JAK2 signaling. We therefore developed a conditionally inducible mouse model allowing for sequential activation, and then inactivation, of Jak2V617F from its endogenous locus using a combined Dre-rox/Cre-lox dual-recombinase system. Jak2V617F deletion abrogates MPN features, induces depletion of mutant-specific hematopoietic stem/progenitor cells, and extends overall survival to an extent not observed with pharmacologic JAK inhibition, including when cooccurring with somatic Tet2 loss. Our data suggest JAK2V617F represents the best therapeutic target in MPNs and demonstrate the therapeutic relevance of a dual-recombinase system to assess mutant-specific oncogenic dependencies in vivo
Recommended from our members
Cancer therapy shapes the fitness landscape of clonal hematopoiesis.
Acquired mutations are pervasive across normal tissues. However, understanding of the processes that drive transformation of certain clones to cancer is limited. Here we study this phenomenon in the context of clonal hematopoiesis (CH) and the development of therapy-related myeloid neoplasms (tMNs). We find that mutations are selected differentially based on exposures. Mutations in ASXL1 are enriched in current or former smokers, whereas cancer therapy with radiation, platinum and topoisomerase II inhibitors preferentially selects for mutations in DNA damage response genes (TP53, PPM1D, CHEK2). Sequential sampling provides definitive evidence that DNA damage response clones outcompete other clones when exposed to certain therapies. Among cases in which CH was previously detected, the CH mutation was present at tMN diagnosis. We identify the molecular characteristics of CH that increase risk of tMN. The increasing implementation of clinical sequencing at diagnosis provides an opportunity to identify patients at risk of tMN for prevention strategies
Cancer therapy shapes the fitness landscape of clonal hematopoiesis.
Acquired mutations are pervasive across normal tissues. However, understanding of the processes that drive transformation of certain clones to cancer is limited. Here we study this phenomenon in the context of clonal hematopoiesis (CH) and the development of therapy-related myeloid neoplasms (tMNs). We find that mutations are selected differentially based on exposures. Mutations in ASXL1 are enriched in current or former smokers, whereas cancer therapy with radiation, platinum and topoisomerase II inhibitors preferentially selects for mutations in DNA damage response genes (TP53, PPM1D, CHEK2). Sequential sampling provides definitive evidence that DNA damage response clones outcompete other clones when exposed to certain therapies. Among cases in which CH was previously detected, the CH mutation was present at tMN diagnosis. We identify the molecular characteristics of CH that increase risk of tMN. The increasing implementation of clinical sequencing at diagnosis provides an opportunity to identify patients at risk of tMN for prevention strategies
Cost Analysis and Policy Implications of a Pediatric Palliative Care Program
ContextIn 2010, California launched Partners for Children (PFC), a pediatric palliative care pilot program offering hospice-like services for children eligible for full-scope Medicaid delivered concurrently with curative care, regardless of the child's life expectancy.ObjectivesWe assessed the change from before PFC enrollment to the enrolled period in 1) health care costs per enrollee per month (PEPM), 2) costs by service type and diagnosis category, and 3) health care utilization (days of inpatient care and length of hospital stay).MethodsA pre-post analysis compared enrollees' health care costs and utilization up to 24 months before enrollment with their costs during participation in the pilot, from January 2010 through December 2012. Analyses were conducted using paid Medicaid claims and program enrollment data.ResultsThe average PEPM health care costs of program enrollees decreased by 4897 PEPM. PFC enrollees experienced a nearly 50% reduction in the average number of inpatient days per month, from 4.2 to 2.3. Average length of stay per hospitalization dropped from an average of 16.7 days before enrollment to 6.5 days while in the program.ConclusionThrough the provision of home-based therapeutic services, 24/7 access to medical advice, and enhanced, personally tailored care coordination, PFC demonstrated an effective way to reduce costs for children with life-limiting conditions by moving from costly inpatient care to more coordinated and less expensive outpatient care. PFC's home-based care strategy is a cost-effective model for pediatric palliative care elsewhere
Cardiac myosin binding protein C phosphorylation in cardiac disease
Perturbations in sarcomeric function may in part underlie systolic and diastolic dysfunction of the failing heart. Sarcomeric dysfunction has been ascribed to changes in phosphorylation status of sarcomeric proteins caused by an altered balance between intracellular kinases and phosphatases during the development of cardiac disease. In the present review we discuss changes in phosphorylation of the thick filament protein myosin binding protein C (cMyBP-C) reported in failing myocardium, with emphasis on phosphorylation changes observed in familial hypertrophic cardiomyopathy caused by mutations in MYBPC3. Moreover, we will discuss assays which allow to distinguish between functional consequences of mutant sarcomeric proteins and (mal)adaptive changes in sarcomeric protein phosphorylation
The Origins of AGN Obscuration: The 'Torus' as a Dynamical, Unstable Driver of Accretion
Multi-scale simulations have made it possible to follow gas inflows onto
massive black holes (BHs) from galactic scales to the accretion disk. When
sufficient gas is driven towards the BH, gravitational instabilities
generically form lopsided, eccentric disks that propagate inwards. The lopsided
stellar disk exerts a strong torque on the gas disk, driving inflows that fuel
rapid BH growth. Here, we investigate whether the same gas disk is the 'torus'
invoked to explain obscured AGN. The disk is generically thick and has
characteristic ~1-10 pc sizes and masses resembling those required of the
torus. The scale heights and obscured fractions of the predicted torii are
substantial even in the absence of strong stellar feedback providing the
vertical support. Rather, they can be maintained by strong bending modes and
warps excited by the inflow-generating instabilities. Other properties commonly
attributed to feedback processes may be explained by dynamical effects:
misalignment between torus and host galaxy, correlations between local SFR and
turbulent gas velocities, and dependence of obscured fractions on AGN
luminosity or SFR. We compare the predicted torus properties with observations
of gas surface density profiles, kinematics, scale heights, and SFR densities
in AGN nuclei, and find that they are consistent. We argue that it is not
possible to reproduce these observations and the observed column density (N_H)
distribution without a clumpy gas distribution, but allowing for clumping on
small scales the predicted N_H distribution is in good agreement with
observations from 10^20-27 cm^-2. We examine how N_H scales with galaxy and AGN
properties, and find that AGN feedback may be necessary to explain some trends
with luminosity and/or redshift. The torus is not merely a bystander or passive
fuel source for accretion, but is itself the mechanism driving accretion.Comment: 20 pages, 10 figures, accepted to MNRAS (matches accepted version
The Netherlands study of depression in older persons (NESDO); a prospective cohort study
<p>Abstract</p> <p>Background</p> <p>To study late-life depression and its unfavourable course and co morbidities in The Netherlands.</p> <p>Methods</p> <p>We designed the Netherlands Study of Depression in Older Persons (NESDO), a multi-site naturalistic prospective cohort study which makes it possible to examine the determinants, the course and the consequences of depressive disorders in older persons over a period of six years, and to compare these with those of depression earlier in adulthood.</p> <p>Results</p> <p>From 2007 until 2010, the NESDO consortium has recruited 510 depressed and non depressed older persons (≥ 60 years) at 5 locations throughout the Netherlands. Depressed persons were recruited from both mental health care institutes and general practices in order to include persons with late-life depression in various developmental and severity stages. Non-depressed persons were recruited from general practices. The baseline assessment included written questionnaires, interviews, a medical examination, cognitive tests and collection of blood and saliva samples. Information was gathered about mental health outcomes and demographic, psychosocial, biological, cognitive and genetic determinants. The baseline NESDO sample consists of 378 depressed (according to DSM-IV criteria) and 132 non-depressed persons aged 60 through 93 years. 95% had a major depression and 26.5% had dysthymia. Mean age of onset of the depressive disorder was around 49 year. For 33.1% of the depressed persons it was their first episode. 41.0% of the depressed persons had a co morbid anxiety disorder. Follow up assessments are currently going on with 6 monthly written questionnaires and face-to-face interviews after 2 and 6 years.</p> <p>Conclusions</p> <p>The NESDO sample offers the opportunity to study the neurobiological, psychosocial and physical determinants of depression and its long-term course in older persons. Since largely similar measures were used as in the Netherlands Study of Depression and Anxiety (NESDA; age range 18-65 years), data can be pooled thus creating a large longitudinal database of clinically depressed persons with adequate power and a large set of neurobiological, psychosocial and physical variables from both younger and older depressed persons.</p
Populist Mobilization: A New Theoretical Approach to Populism*
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112280/1/j.1467-9558.2011.01388.x.pd
- …