1,600 research outputs found
A liquid metal-based process for tuning the thermoelectric properties of bismuth indium systems
To obtain the optimum performance of thermoelectric materials, engineering their characteristics, such as crystal structures and phases, is critical. Liquid metal-based processes are great methods for controlling and tuning such properties. In this study, indium (In), of different concentrations, is introduced into bismuth (Bi) via a liquid metal-based process to tailor the crystallization arrangements and investigate the thermoelectric properties of the Bi-In systems. These systems were prepared by a liquid metal-based melting and solidification process. Thermoelectric properties, including the Seebeck coefficient, thermal conductivity, and resistivity, were analyzed using in-house built apparatus units. The sample with 2% indium concentration showed the highest Seebeck coefficient and electrical resistivity. Thermal conductivity was observed to decrease with increasing indium concentration up to 5%, followed by a reverse trend above this concentration. Dominated by the thermal conductivity effect, the sample with 5% indium concentration showed the highest average value for the figure of merit (zT) for the Bi-In systems. The zT value of this sample was nearly twice than that of the pristine bismuth. According to our analyses, this increase could be attributed to the crystal modalities of the formed BiIn crystals with optimum crystallite dimensions and distributions, along with the emergence of specific diffraction peaks, in the pool of bismuth. This study provides a facile and low-cost liquid metal-based pathway for designing thermoelectric materials by tuning their crystal structures and orientations using liquid metal-enabled processes
Preterm birth a long distance from home and its significant social and financial stress
The present paper reports a retrospective cohort of preterm infants admitted to our hospital who delivered outside the normal geographical catchment area of the mother's local level three neonatal nursery. Nineteen mothers had 21 preterm infants (23.1-34.9 weeks, 500-2330 g born) where 14 infants required ventilation (median 57 h, range 3-428). Eighteen survivors had a median length of stay of 41 days (range 3-91). Twelve of 19 mothers were interviewed: all described isolation, loneliness, poor social support and significant financial hardship related to getting their infants back to a local hospital or home. To avoid these problems, we recommend confining travel to within a short distance from home or local maternity unit after 22 weeks
A Regularized Graph Layout Framework for Dynamic Network Visualization
Many real-world networks, including social and information networks, are
dynamic structures that evolve over time. Such dynamic networks are typically
visualized using a sequence of static graph layouts. In addition to providing a
visual representation of the network structure at each time step, the sequence
should preserve the mental map between layouts of consecutive time steps to
allow a human to interpret the temporal evolution of the network. In this
paper, we propose a framework for dynamic network visualization in the on-line
setting where only present and past graph snapshots are available to create the
present layout. The proposed framework creates regularized graph layouts by
augmenting the cost function of a static graph layout algorithm with a grouping
penalty, which discourages nodes from deviating too far from other nodes
belonging to the same group, and a temporal penalty, which discourages large
node movements between consecutive time steps. The penalties increase the
stability of the layout sequence, thus preserving the mental map. We introduce
two dynamic layout algorithms within the proposed framework, namely dynamic
multidimensional scaling (DMDS) and dynamic graph Laplacian layout (DGLL). We
apply these algorithms on several data sets to illustrate the importance of
both grouping and temporal regularization for producing interpretable
visualizations of dynamic networks.Comment: To appear in Data Mining and Knowledge Discovery, supporting material
(animations and MATLAB toolbox) available at
http://tbayes.eecs.umich.edu/xukevin/visualization_dmkd_201
A compact statistical model of the song syntax in Bengalese finch
Songs of many songbird species consist of variable sequences of a finite
number of syllables. A common approach for characterizing the syntax of these
complex syllable sequences is to use transition probabilities between the
syllables. This is equivalent to the Markov model, in which each syllable is
associated with one state, and the transition probabilities between the states
do not depend on the state transition history. Here we analyze the song syntax
in a Bengalese finch. We show that the Markov model fails to capture the
statistical properties of the syllable sequences. Instead, a state transition
model that accurately describes the statistics of the syllable sequences
includes adaptation of the self-transition probabilities when states are
repeatedly revisited, and allows associations of more than one state to the
same syllable. Such a model does not increase the model complexity
significantly. Mathematically, the model is a partially observable Markov model
with adaptation (POMMA). The success of the POMMA supports the branching chain
network hypothesis of how syntax is controlled within the premotor song nucleus
HVC, and suggests that adaptation and many-to-one mapping from neural
substrates to syllables are important features of the neural control of complex
song syntax
First isolation of two colistin-resistant emerging pathogens, Brevundimonas diminuta and Ochrobactrum anthropi, in a woman with cystic fibrosis: a case report
<p>Abstract</p> <p>Introduction</p> <p>Cystic fibrosis afflicted lungs support the growth of many bacteria rarely implicated in other cases of human infections.</p> <p>Case presentation</p> <p>We report the isolation and identification, by 16S rRNA amplification and sequencing, of two emerging pathogens resistant to colistin, <it>Brevundimonas diminuta </it>and <it>Ochrobactrum anthropi</it>, in a 17-year-old woman with cystic fibrosis and pneumonia. The patient eventually responded well to a 2-week regime of imipenem and tobramycin.</p> <p>Conclusion</p> <p>Our results clearly re-emphasize the emergence of new colistin-resistant pathogens in patients with cystic fibrosis.</p
Disruption of Murine mp29/Syf2/Ntc31 Gene Results in Embryonic Lethality with Aberrant Checkpoint Response
Human p29 is a putative component of spliceosomes, but its role in pre-mRNA is elusive. By siRNA knockdown and stable overexpression, we demonstrated that human p29 is involved in DNA damage response and Fanconi anemia pathway in cultured cells. In this study, we generated p29 knockout mice (mp29GT/GT) using the mp29 gene trap embryonic stem cells to study the role of mp29 in DNA damage response in vivo. Interruption of mp29 at both alleles resulted in embryonic lethality. Embryonic abnormality occurred as early as E6.5 in mp29GT/GT mice accompanied with decreased mRNA levels of α-tubulin and Chk1. The reduction of α-tubulin and Chk1 mRNAs is likely due to an impaired post-transcriptional event. An aberrant G2/M checkpoint was found in mp29 gene trap embryos when exposed to aphidicolin and UV light. This embryonic lethality was rescued by crossing with mp29 transgenic mice. Additionally, the knockdown of zfp29 in zebrafish resulted in embryonic death at 72 hours of development postfertilization (hpf). A lower level of acetylated α-tubulin was also observed in zfp29 morphants. Together, these results illustrate an indispensable role of mp29 in DNA checkpoint response during embryonic development
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Multiparticle azimuthal correlations for extracting event-by-event elliptic and triangular flow in Au + Au collisions at sNN =200 GeV
We present measurements of elliptic and triangular azimuthal anisotropy of charged particles detected at forward rapidity 1<|η|<3 in Au + Au collisions at sNN=200 GeV, as a function of centrality. The multiparticle cumulant technique is used to obtain the elliptic flow coefficients v2{2},v2{4},v2{6}, and v2{8}, and triangular flow coefficients v3{2} and v3{4}. Using the small-variance limit, we estimate the mean and variance of the event-by-event v2 distribution from v2{2} and v2{4}. In a complementary analysis, we also use a folding procedure to study the distributions of v2 and v3 directly, extracting both the mean and variance. Implications for initial geometrical fluctuations and their translation into the final-state momentum distributions are discussed
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