1,997 research outputs found
Revisiting Consistent Hashing with Bounded Loads
Dynamic load balancing lies at the heart of distributed caching. Here, the
goal is to assign objects (load) to servers (computing nodes) in a way that
provides load balancing while at the same time dynamically adjusts to the
addition or removal of servers. One essential requirement is that the addition
or removal of small servers should not require us to recompute the complete
assignment. A popular and widely adopted solution is the two-decade-old
Consistent Hashing (CH). Recently, an elegant extension was provided to account
for server bounds. In this paper, we identify that existing methodologies for
CH and its variants suffer from cascaded overflow, leading to poor load
balancing. This cascading effect leads to decreasing performance of the hashing
procedure with increasing load. To overcome the cascading effect, we propose a
simple solution to CH based on recent advances in fast minwise hashing. We
show, both theoretically and empirically, that our proposed solution is
significantly superior for load balancing and is optimal in many senses. On the
AOL search dataset and Indiana University Clicks dataset with real user
activity, our proposed solution reduces cache misses by several magnitudes
Transcriptome Analysis of CD4+ T Cells in Coeliac Disease Reveals Imprint of BACH2 and IFNγ Regulation
peer-reviewedData Availability: The raw sequencing reads (FASTQ files) and sequence read counts mapped to UCSC hg19 for each of the 74 transcriptomes sequenced in this study have been deposited at Gene Expression Omnibus (GEO) accession GSE69549.This project was funded by Science Foundation Ireland Grant number 09/IN.1/B2640 to RM.Genetic studies have to date identified 43 genome wide significant coeliac disease susceptibility (CD) loci comprising over 70 candidate genes. However, how altered regulation of such disease associated genes contributes to CD pathogenesis remains to be elucidated. Recently there has been considerable emphasis on characterising cell type specific and stimulus dependent genetic variants. Therefore in this study we used RNA sequencing to profile over 70 transcriptomes of CD4+ T cells, a cell type crucial for CD pathogenesis, in both stimulated and resting samples from individuals with CD and unaffected controls. We identified extensive transcriptional changes across all conditions, with the previously established CD gene IFNy the most strongly up-regulated gene (log2 fold change 4.6; Padjusted = 2.40x10-11) in CD4+ T cells from CD patients compared to controls. We show a significant correlation of differentially expressed genes with genetic studies of the disease to date (Padjusted = 0.002), and 21 CD candidate susceptibility genes are differentially expressed under one or more of the conditions used in this study. Pathway analysis revealed significant enrichment of immune related processes. Co-expression network analysis identified several modules of coordinately expressed CD genes. Two modules were particularly highly enriched for differentially expressed genes (P</iframe
Building dashboard : using real-time web-based utility usage feedback to promote energy conservation and education in residential halls
Project Leaders: Ben Datema, Paul Coleman, Frankie Minor, Jan Weaver, Pat MargherioMU Interdisciplinary Innovations Fun
Distinguishing Spin-Aligned and Isotropic Black Hole Populations With Gravitational Waves
The first direct detections of gravitational waves from merging binary black
holes open a unique window into the binary black hole formation environment.
One promising environmental signature is the angular distribution of the black
hole spins; systems formed through dynamical interactions among already-compact
objects are expected to have isotropic spin orientations whereas binaries
formed from pairs of stars born together are more likely to have spins
preferentially aligned with the binary orbital angular momentum. We consider
existing gravitational wave measurements of the binary effective spin, the
best-measured combination of spin parameters, in the four likely binary black
hole detections GW150914, LVT151012, GW151226, and GW170104. If binary black
hole spin magnitudes extend to high values we show that the data exhibit a
( odds ratio) preference for an isotropic angular
distribution over an aligned one. By considering the effect of 10 additional
detections, we show that such an augmented data set would enable in most cases
a preference stronger than ( odds ratio). The
existing preference for either an isotropic spin distribution or low spin
magnitudes for the observed systems will be confirmed (or overturned)
confidently in the near future.Comment: 32 pages, 9 figures, code and document at
https://github.com/farr/AlignedVersusIsoSpin/ ; updated to use custom LaTeX
class to include figures in PD
The Effective Kahler Potential, Metastable Vacua and R-Symmetry Breaking in O'Raifeartaigh Models
Much has been learned about metastable vacua and R-symmetry breaking in
O'Raifeartaigh models. Such work has largely been done from the perspective of
the superpotential and by including Coleman-Weinberg corrections to the scalar
potential. Instead, we consider these ideas from the perspective of the one
loop effective Kahler potential. We translate known ideas to this framework and
construct convenient formulas for computing individual terms in the expanded
effective Kahler potential. We do so for arbitrary R-charge assignments and
allow for small R-symmetry violating terms so that both spontaneous and
explicit R-symmetry breaking is allowed in our analysis.Comment: 15 pages; minor correction
Geometric Metastability, Quivers and Holography
We use large N duality to study brane/anti-brane configurations on a class of
Calabi-Yau manifolds. With only branes present, the Calabi-Yau manifolds in
question give rise to N=2 ADE quiver theories deformed by superpotential terms.
We show that the large N duality conjecture of hep-th/0610249 reproduces
correctly the known qualitative features of the brane/anti-brane physics. In
the supersymmetric case, the gauge theories have Seiberg dualities which are
represented as flops in the geometry. Moreover, the holographic dual geometry
encodes the whole RG flow of the gauge theory. In the non-supersymmetric case,
the large N duality predicts that the brane/anti-brane theories also enjoy such
dualities, and allows one to pick out the good description at a given energy
scale.Comment: v2: 56 pages, 4 figures, harvmac, abstract correcte
To Sleep, Perchance to Dream: Acute and Chronic Sleep Deprivation in Acute Care Surgeons
Background
Acute and chronic sleep deprivation are significantly associated with depressive symptoms and felt to be contributors to the development of burnout. In-house call (IHC) inherently includes frequent periods of disrupted sleep and is common amongst acute care surgeons (ACS). The relationship between IHC and sleep deprivation (SD) amongst ACS has not been previously studied. The goal of this study was to determine prevalence and patterns of SD in ACS.
Study
Design: A prospective study of ACS with IHC responsibilities from two Level I trauma centers was performed. Participants wore a sleep tracking device continuously over a 3-month period. Data collected included age, gender, schedule of IHC, hours and pattern of each sleep stage (light, slow wave (SWS), and REM), and total hours of sleep. Sleep patterns were analyzed for each night excluding IHC and categorized as normal (N), acute sleep deprivation (ASD), or chronic sleep deprivation (CSD).
Results
1421 nights were recorded amongst 17 ACS. (35.3% female; ages 37-65, mean 45.5 years). Excluding IHC, average amount of sleep was 6.54 hours with 64.8% of sleep patterns categorized as ASD or CSD. Average amount of sleep was significantly higher on post-call day 1 (6.96 hours, p=0.0016), but decreased significantly on post-call day 2 (6.33 hours, p=0.0006). Sleep patterns with ASD and CSD peaked on post-call day 2, and returned to baseline on post-call day 3 (p=0.046).
Conclusion
Sleep patterns consistent with ASD and CSD are common amongst ACS and worsen on post-call day 2. Baseline sleep patterns were not recovered until post-call day 3. Future study is needed to identify factors which impact physiologic recovery after IHC and further elucidate the relationship between SD and burnout
Quantum and Thermal Fluctuations in Field Theory
Blocking transformation is performed in quantum field theory at finite
temperature. It is found that the manner temperature deforms the renormalized
trajectories can be used to understand better the role played by the quantum
fluctuations. In particular, it is conjectured that domain formation and mass
parameter generation can be observed in theories without spontaneous symmetry
breaking.Comment: 27pp+7 figures, MIT-CTP-214
A Quantum Mechanical Model of Spherical Supermembranes
We present a quantum mechanical model of spherical supermembranes. Using
superfields to represent the cartesian coordinates of the membrane, we are able
to exactly determine its supersymmetric vacua. We find there are two classical
vacua, one corresponding to an extended membrane and one corresponding to a
point-like membrane. For the case, instanton effects then
lift these vacua to massive states. For the case, there is
no instanton tunneling, and the vacua remain massless. Similarities to
spherical supermembranes as giant gravitons and in Matrix theory on pp-waves is
discussed.Comment: 9 page
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