3,244 research outputs found
Extended soft wall model with background related to features of QCD thermodynamics
The soft wall model is extended to accommodate at the same time (i)
approximately linear meson Regge trajectories at zero temperature ,
(ii) various options for the thermodynamics with reference to QCD (cross over
or second-order transition or first-order transition at ), and (iii) the
appearance of vector meson states at . While the vector meson
masses display some modest model dependence very near to , they stay below
to good accuracy independent of the temperature, that is nearly as at
, thus being very consistent with the thermo-statistical models widely
employed in analyses of the hadron yields in relativistic heavy-ion collisions
in a region where baryon densitiy effects can be neglected and the vacuum
hadron masses are used
Using GWAS Data to Identify Copy Number Variants Contributing to Common Complex Diseases
Copy number variants (CNVs) account for more polymorphic base pairs in the
human genome than do single nucleotide polymorphisms (SNPs). CNVs encompass
genes as well as noncoding DNA, making these polymorphisms good candidates for
functional variation. Consequently, most modern genome-wide association studies
test CNVs along with SNPs, after inferring copy number status from the data
generated by high-throughput genotyping platforms. Here we give an overview of
CNV genomics in humans, highlighting patterns that inform methods for
identifying CNVs. We describe how genotyping signals are used to identify CNVs
and provide an overview of existing statistical models and methods used to
infer location and carrier status from such data, especially the most commonly
used methods exploring hybridization intensity. We compare the power of such
methods with the alternative method of using tag SNPs to identify CNV carriers.
As such methods are only powerful when applied to common CNVs, we describe two
alternative approaches that can be informative for identifying rare CNVs
contributing to disease risk. We focus particularly on methods identifying de
novo CNVs and show that such methods can be more powerful than case-control
designs. Finally we present some recommendations for identifying CNVs
contributing to common complex disorders.Comment: Published in at http://dx.doi.org/10.1214/09-STS304 the Statistical
Science (http://www.imstat.org/sts/) by the Institute of Mathematical
Statistics (http://www.imstat.org
Mechanics reveals the biological trigger in wrinkly fingers
The final publication is available at Springer via http://dx.doi.org/10.1007/s10439-016-1764-6Fingertips wrinkle due to long exposure to water. The biological reason for this morphological change is unclear and still not fully understood. There are two main hypotheses for the underlying mechanism of fingertip wrinkling: the âshrinkâ model (in which the wrinkling is driven by the contraction of the lower layers of skin, associated with the shrinking of the underlying vasculature), and the âswellâ model (in which the wrinkling is driven by the swelling of the upper layers of the skin, associated with osmosis). In reality, contraction of the lower layers of the skin and swelling of the upper layers will happen simultaneously. However, the relative importance of these two mechanisms to drive fingertip wrinkling also remains unclear. Simulating the swelling in the upper layers of skin alone, which is associated with neurological disorders, we found that wrinkles appeared above an increase of volume of Ë10%.Ë10%. Therefore, the upper layers can not exceed this swelling level in order to not contradict in vivo observations in patients with such neurological disorders. Simulating the contraction of the lower layers of the skin alone, we found that the volume have to decrease a Ë20%Ë20% to observe wrinkles. Furthermore, we found that the combined effect of both mechanisms leads to pronounced wrinkles even at low levels of swelling and contraction when individually they do not. This latter results indicates that the collaborative effect of both hypothesis are needed to induce wrinkles in the fingertips. Our results demonstrate how models from continuum mechanics can be successfully applied to testing hypotheses for the mechanisms that underly fingertip wrinkling, and how these effects can be quantified.Peer ReviewedPostprint (published version
Influence of dietary linoleic acid intake with different fat intakes on arachidonic acid concentrations in plasma and platelet lipids and eicosanoid biosynthesis in female volunteers
Background/Aim: N-6 fatty acids are considered to promote diseases prevalent in industrialized countries and characterized by an increased eicosanoid biosynthesis from arachidonic acid (AA). We investigated the impact of the linoleic acid (LA) intake on AA levels in humans. Methods: Six healthy female volunteers (age range 2334 years) were given liquid formula diets (LFD) devoid of AA for 6 weeks, providing a constant intake of zero energy% (LFD 0: protein 15%, carbohydrates 85%) or 20 energy% (LFD 20: protein 15%, carbohydrates 55%, fat 30%) LA, for 3 weeks each. Fatty acids of plasma cholesteryl esters and platelet lipids were determined each week, and the prostaglandin biosynthesis was measured in 24-hour urine samples. Results: LFD 0 increased (+31% of initial value) and LFD 20 lowered (-30% of initial value) the percentage of AA in plasma cholesteryl esters and platelet lipids. Moreover, absence of dietary AA lowered the percentages of AA in plasma (-31% week 0 vs. week 6) and platelet (-11%) lipids, indicating a low transformation of LA. LFD 0 reduced urinary metabolite levels of prostaglandins D, E, and F in 24-hour urine samples (-48%, p < 0.001) within 24 h, but did not significantly affect platelet aggregation (-10%) and thromboxane formation (-25%). LFD 20 significantly lowered platelet aggregation (-25%) and thromboxane formation (-43%). The prostaglandin metabolite levels increased during the first 10 days, declined thereafter, and were lower than the preexperimental values at the end of the 3-week period. Conclusions: The results show that dietary LA does not increase the AA levels in plasma or platelet lipids and does not persistently contribute to prostaglandin biosynthesis which is increased by AA intake with Western diets
Inter-species Tunneling in One-dimensional Bose Mixtures
We study the ground-state properties and quantum dynamics of few-boson
mixtures with strong inter-species repulsion in one-dimensional traps. If one
species localizes at the center, e.g., due to a very large mass compared to the
other component, it represents an effective barrier for the latter and the
system can be mapped onto identical bosons in a double well. For weaker
localization, the barrier atoms begin to respond to the light component,
leading to an induced attraction between the mobile atoms that may even
outweigh their bare intra-species repulsion. To explain the resulting effects,
we derive an effective Hubbard model for the lighter species accounting for the
backaction of the barrier in correction terms to the lattice parameters. Also
the tunneling is drastically affected: Varying the degree of localization of
the "barrier" atoms, the dynamics of intrinsically noninteracting bosons can
change from Rabi oscillations to effective pair tunneling. For identical
fermions (or fermionized bosons) this leads to the tunneling of attractively
bound pairs.Comment: 13 pages, 11 figures; v2 reflects major revisio
Decentralized Cooperative Planning for Automated Vehicles with Continuous Monte Carlo Tree Search
Urban traffic scenarios often require a high degree of cooperation between
traffic participants to ensure safety and efficiency. Observing the behavior of
others, humans infer whether or not others are cooperating. This work aims to
extend the capabilities of automated vehicles, enabling them to cooperate
implicitly in heterogeneous environments. Continuous actions allow for
arbitrary trajectories and hence are applicable to a much wider class of
problems than existing cooperative approaches with discrete action spaces.
Based on cooperative modeling of other agents, Monte Carlo Tree Search (MCTS)
in conjunction with Decoupled-UCT evaluates the action-values of each agent in
a cooperative and decentralized way, respecting the interdependence of actions
among traffic participants. The extension to continuous action spaces is
addressed by incorporating novel MCTS-specific enhancements for efficient
search space exploration. The proposed algorithm is evaluated under different
scenarios, showing that the algorithm is able to achieve effective cooperative
planning and generate solutions egocentric planning fails to identify
Decentralized Cooperative Planning for Automated Vehicles with Hierarchical Monte Carlo Tree Search
Today's automated vehicles lack the ability to cooperate implicitly with
others. This work presents a Monte Carlo Tree Search (MCTS) based approach for
decentralized cooperative planning using macro-actions for automated vehicles
in heterogeneous environments. Based on cooperative modeling of other agents
and Decoupled-UCT (a variant of MCTS), the algorithm evaluates the
state-action-values of each agent in a cooperative and decentralized manner,
explicitly modeling the interdependence of actions between traffic
participants. Macro-actions allow for temporal extension over multiple time
steps and increase the effective search depth requiring fewer iterations to
plan over longer horizons. Without predefined policies for macro-actions, the
algorithm simultaneously learns policies over and within macro-actions. The
proposed method is evaluated under several conflict scenarios, showing that the
algorithm can achieve effective cooperative planning with learned macro-actions
in heterogeneous environments
- âŠ