2,019 research outputs found
Fully Dynamic Matching in Bipartite Graphs
Maximum cardinality matching in bipartite graphs is an important and
well-studied problem. The fully dynamic version, in which edges are inserted
and deleted over time has also been the subject of much attention. Existing
algorithms for dynamic matching (in general graphs) seem to fall into two
groups: there are fast (mostly randomized) algorithms that do not achieve a
better than 2-approximation, and there slow algorithms with \O(\sqrt{m})
update time that achieve a better-than-2 approximation. Thus the obvious
question is whether we can design an algorithm -- deterministic or randomized
-- that achieves a tradeoff between these two: a approximation
and a better-than-2 approximation simultaneously. We answer this question in
the affirmative for bipartite graphs.
Our main result is a fully dynamic algorithm that maintains a 3/2 + \eps
approximation in worst-case update time O(m^{1/4}\eps^{/2.5}). We also give
stronger results for graphs whose arboricity is at most \al, achieving a (1+
\eps) approximation in worst-case time O(\al (\al + \log n)) for constant
\eps. When the arboricity is constant, this bound is and when the
arboricity is polylogarithmic the update time is also polylogarithmic.
The most important technical developement is the use of an intermediate graph
we call an edge degree constrained subgraph (EDCS). This graph places
constraints on the sum of the degrees of the endpoints of each edge: upper
bounds for matched edges and lower bounds for unmatched edges. The main
technical content of our paper involves showing both how to maintain an EDCS
dynamically and that and EDCS always contains a sufficiently large matching. We
also make use of graph orientations to help bound the amount of work done
during each update.Comment: Longer version of paper that appears in ICALP 201
Phase II, Multicenter, Randomized Trial of CPX-351 (cytarabine: daunorubicin) Liposome Injection Versus Intensive Salvage Therapy in Adults With First Relapse AML
BACKGROUNDCPX-351 is a liposome-encapsulated fixed-molar-ratio formulation of cytarabine and daunorubicin that exploits molar ratio-dependent drug-drug synergy to enhance antileukemic efficacy. METHODSThis phase II study randomized 125 patients 2:1 to CPX-351 or investigators\u27 choice of first salvage chemotherapy. Patients with acute myeloid leukemia (AML) in first relapse after initial Complete Remission (CR) lasting 1 month were stratified per the European Prognostic Index (EPI) into favorable, intermediate, and poor-risk groups based on duration of first CR, cytogenetics, age, and transplant history. Control salvage treatment was usually based on cytarabine and anthracycline, often with 1 or more additional agents. Survival at 1 year was the primary efficacy end point. RESULTSPatient characteristics were well balanced between the 2 study arms. Improvements in efficacy outcomes were observed following CPX-351, but did not meet prospectively defined statistical criteria for 1-year survival improvement in the overall population. Subset analyses of the EPI-defined poor-risk strata demonstrated higher response rates (39.3% vs 27.6%) and improvements in event-free survival (HR, 0.63; P=.08) and overall survival (HR, 0.55; P=.02). Also, 60-day mortality was lower in the CPX-351 study arm for poor-risk patients (16.1% vs 24.1%). CONCLUSIONSTaken together, the data suggest possible improved outcomes in CPX-351-treated first relapse AML patients with EPI-defined poor-risk disease. Cancer 2015;121:234-42. (c) 2014 American Cancer Society. CPX-351, a liposome-encapsulated fixed-molar-ratio formulation of cytarabine and daunorubicin, exploits molar ratio-dependent drug-drug synergy to enhance antileukemic efficacy. A randomized phase II study comparing CPX-351 with investigators\u27 choice of first salvage therapy in first-relapse patients demonstrated improved response, event-free survival, and overall survival (HR, 0.55; P=.02) in the poor-risk strata
Early postpartum restingâstate functional connectivity for mothers receiving buprenorphine treatment for opioid use disorder: A pilot study
Between 1999 and 2014, the prevalence of opioid use disorder (OUD) among pregnant women quadrupled in the USA. The standard treatment for peripartum women with OUD is buprenorphine. However, the maternal behavior neurocircuit that regulates maternal behavior and motherâinfant bonding has not been previously studied for human mothers receiving buprenorphine treatment for OUD (BT). Rodent research shows opioid effects on reciprocal inhibition between maternal care and defence maternal brain subsystems: the hypothalamus and periaqueductal gray, respectively. We conducted a longitudinal functional magnetic resonance imaging (fMRI) pilot study in humans to specifically examine restingâstate functional connectivity (rsâFC) between the periaqueductal gray and hypothalamus, as well as to explore associations with maternal bonding for BT. We studied 32 mothers who completed fMRI scans at 1Â month (T1) and 4Â months postpartum (T2), including seven mothers receiving buprenorphine for OUD and 25 nonâOUD mothers as a comparison group (CG). The participants underwent a 6âminute restingâstate fMRI scan at each time point. We measured potential bonding impairments using the Postpartum Bonding Questionnaire to explore how rsâFC with periaqueductal gray is associated with bonding impairments. Compared to CG, BT mothers differed in periaqueductal grayâdependent rsâFC with the hypothalamus, amygdala, insular cortex and other brain regions at T1, with many of these differences disappearing at T2, suggesting potential therapeutic effects of continuing buprenorphine treatment. In contrast, the ârejection and pathological angerâ subscale of the Postpartum Bonding Questionnaire at T1 and T2 was associated with the T1âtoâT2 increases in periaqueductal grayâdependent rsâFC with the hypothalamus and amygdala. Preliminary evidence links maternal bonding problems for mothers with OUD early in the postpartum to connectivity between specific care and defence maternal brain circuits, which may be mitigated by buprenorphine treatment. This exploratory study supports a potential mechanism for investigating both the therapeutic benefits and risks of opioids for maternal care and bonding with infants.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151866/1/jne12770.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151866/2/jne12770_am.pd
Evidence-based decision support for pediatric rheumatology reduces diagnostic errors.
BACKGROUND: The number of trained specialists world-wide is insufficient to serve all children with pediatric rheumatologic disorders, even in the countries with robust medical resources. We evaluated the potential of diagnostic decision support software (DDSS) to alleviate this shortage by assessing the ability of such software to improve the diagnostic accuracy of non-specialists.
METHODS: Using vignettes of actual clinical cases, clinician testers generated a differential diagnosis before and after using diagnostic decision support software. The evaluation used the SimulConsultÂź DDSS tool, based on Bayesian pattern matching with temporal onset of each finding in each disease. The tool covered 5405 diseases (averaging 22 findings per disease). Rheumatology content in the database was developed using both primary references and textbooks. The frequency, timing, age of onset and age of disappearance of findings, as well as their incidence, treatability, and heritability were taken into account in order to guide diagnostic decision making. These capabilities allowed key information such as pertinent negatives and evolution over time to be used in the computations. Efficacy was measured by comparing whether the correct condition was included in the differential diagnosis generated by clinicians before using the software ( unaided ), versus after use of the DDSS ( aided ).
RESULTS: The 26 clinicians demonstrated a significant reduction in diagnostic errors following introduction of the software, from 28% errors while unaided to 15% using decision support (pâ\u3câ0.0001). Improvement was greatest for emergency medicine physicians (pâ=â0.013) and clinicians in practice for less than 10 years (pâ=â0.012). This error reduction occurred despite the fact that testers employed an open book approach to generate their initial lists of potential diagnoses, spending an average of 8.6 min using printed and electronic sources of medical information before using the diagnostic software.
CONCLUSIONS: These findings suggest that decision support can reduce diagnostic errors and improve use of relevant information by generalists. Such assistance could potentially help relieve the shortage of experts in pediatric rheumatology and similarly underserved specialties by improving generalists\u27 ability to evaluate and diagnose patients presenting with musculoskeletal complaints.
TRIAL REGISTRATION: ClinicalTrials.gov ID: NCT02205086
Toward High-Precision Measures of Large-Scale Structure
I review some results of estimation of the power spectrum of density
fluctuations from galaxy redshift surveys and discuss advances that may be
possible with the Sloan Digital Sky Survey. I then examine the realities of
power spectrum estimation in the presence of Galactic extinction, photometric
errors, galaxy evolution, clustering evolution, and uncertainty about the
background cosmology.Comment: 24 pages, including 11 postscript figures. Uses crckapb.sty (included
in submission). To appear in ``Ringberg Workshop on Large-Scale Structure,''
ed D. Hamilton (Kluwer, Amsterdam), p. 39
After the sunset: the residual effect of temporary legislation
The difference between permanent legislation and temporary legislation is the default rule of termination: permanent legislation governs perpetually, while temporary legislation governs for a limited time. Recent literature on legislative timing rules considers the effect of temporary legislation to stop at the moment of expiration. When the law expires, so does its regulatory effect. This article extends that literature by examining the effect of temporary legislation beyond its expiration. We show that in addition to affecting compliance behavior which depends on statutory enforcement, temporary legislation also affects compliance behavior which does not depend on statutory enforcement, and more generally, organizational behavior after a sunset. When temporary legislation expires therefore, it can continue to administer regulatory and other effects. We specify the conditions for this process and give the optimal legislative response
Evolution in the Cluster Early-type Galaxy Size-Surface Brightness Relation at z =~ 1
We investigate the evolution in the distribution of surface brightness, as a
function of size, for elliptical and S0 galaxies in the two clusters RDCS
J1252.9-2927, z=1.237 and RX J0152.7-1357, z=0.837. We use multi-color imaging
with the Advanced Camera for Surveys on the Hubble Space Telescope to determine
these sizes and surface brightnesses. Using three different estimates of the
surface brightnesses, we find that we reliably estimate the surface brightness
for the galaxies in our sample with a scatter of < 0.2 mag and with systematic
shifts of \lesssim 0.05 mag. We construct samples of galaxies with early-type
morphologies in both clusters. For each cluster, we use a magnitude limit in a
band which closely corresponds to the rest-frame B, to magnitude limit of M_B =
-18.8 at z=0, and select only those galaxies within the color-magnitude
sequence of the cluster or by using our spectroscopic redshifts. We measure
evolution in the rest-frame B surface brightness, and find -1.41 \+/- 0.14 mag
from the Coma cluster of galaxies for RDCS J1252.9-2927 and -0.90 \+/- 0.12 mag
of evolution for RX J0152.7-1357, or an average evolution of (-1.13 \+/- 0.15)
z mag. Our statistical errors are dominated by the observed scatter in the
size-surface brightness relation, sigma = 0.42 \+/- 0.05 mag for RX
J0152.7-1357 and sigma = 0.76 \+/- 0.10 mag for RDCS J1252.9-2927. We find no
statistically significant evolution in this scatter, though an increase in the
scatter could be expected. Overall, the pace of luminosity evolution we measure
agrees with that of the Fundamental Plane of early-type galaxies, implying that
the majority of massive early-type galaxies observed at z =~ 1 formed at high
redshifts.Comment: Accepted in ApJ, 16 pages in emulateapj format with 15 eps figures, 6
in colo
Type F congenital quadricuspid aortic valve: A very rare case diagnosed by 3-dimenional transoesophageal echocardiography
Congenital quadricuspid aortic valve (QAV) is a rare cardiac anomaly. Several different anatomical variations of a quadricuspid aortic valve have been described. Aortic regurgitation is the predominant valvular dysfunction associated with QAV and patients tend to present in their 5(th) or 6(th) decade of life. This anomaly is rarely picked up by transthoracic echocardiogram (TTE). A comprehensive transoesophageal echocardiography (TOE) study is more likely to diagnose it. We describe a very rare type of QAV - Type F in a 52-year-old lady who presented with symptoms of shortness of breath and pre-syncope. We include TOE images and intra-operative valve images
Clinicians' caseload management behaviours as explanatory factors in patients' length of time on caseloads : a predictive multilevel study in paediatric community occupational therapy
Peer reviewedPublisher PD
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