223 research outputs found
Low zinc status and absorption exist in infants with jejunostomies or ileostomies which persists after intestinal repair.
There is very little data regarding trace mineral nutrition in infants with small intestinal ostomies. Here we evaluated 14 infants with jejunal or ileal ostomies to measure their zinc absorption and retention and biochemical zinc and copper status. Zinc absorption was measured using a dual-tracer stable isotope technique at two different time points when possible. The first study was conducted when the subject was receiving maximal tolerated feeds enterally while the ostomy remained in place. A second study was performed as soon as feasible after full feeds were achieved after intestinal repair. We found biochemical evidence of deficiencies of both zinc and copper in infants with small intestinal ostomies at both time points. Fractional zinc absorption with an ostomy in place was 10.9% ± 5.3%. After reanastamosis, fractional zinc absorption was 9.4% ± 5.7%. Net zinc balance was negative prior to reanastamosis. In conclusion, our data demonstrate that infants with a jejunostomy or ileostomy are at high risk for zinc and copper deficiency before and after intestinal reanastamosis. Additional supplementation, especially of zinc, should be considered during this time period
Kernel Learning in Ridge Regression "Automatically" Yields Exact Low Rank Solution
We consider kernels of the form
parametrized by . For such kernels, we study a variant of the kernel
ridge regression problem which simultaneously optimizes the prediction function
and the parameter of the reproducing kernel Hilbert space. The
eigenspace of the learned from this kernel ridge regression problem
can inform us which directions in covariate space are important for prediction.
Assuming that the covariates have nonzero explanatory power for the response
only through a low dimensional subspace (central mean subspace), we find that
the global minimizer of the finite sample kernel learning objective is also low
rank with high probability. More precisely, the rank of the minimizing
is with high probability bounded by the dimension of the central mean subspace.
This phenomenon is interesting because the low rankness property is achieved
without using any explicit regularization of , e.g., nuclear norm
penalization.
Our theory makes correspondence between the observed phenomenon and the
notion of low rank set identifiability from the optimization literature. The
low rankness property of the finite sample solutions exists because the
population kernel learning objective grows "sharply" when moving away from its
minimizers in any direction perpendicular to the central mean subspace.Comment: Add code links and correct a figur
Hierarchical accompanying and inhibiting patterns on the spatial arrangement of taxis' local hotspots
Due to the large volume of recording, the complete spontaneity, and the
flexible pick-up and drop-off locations, taxi data portrays a realistic and
detailed picture of urban space use to a certain extent. The spatial
arrangement of pick-up and drop-off hotspots reflects the organizational space,
which has received attention in urban structure studies. Previous studies
mainly explore the hotspots at a large scale by visual analysis or some simple
indexes, where the hotspots usually cover the entire central business district,
train stations, or dense residential areas, reaching a radius of hundreds or
even thousands of meters. However, the spatial arrangement patterns of
small-scale hotspots, reflecting the specific popular pick-up and drop-off
locations, have not received much attention. Using two taxi trajectory datasets
in Wuhan and Beijing, China, this study quantitatively explores the spatial
arrangement of fine-grained pick-up and drop-off local hotspots with different
levels of popularity, where the sizes are adaptively set as 90m*90m in Wuhan
and 105m*105m in Beijing according to the local hotspot identification method.
Results show that popular hotspots tend to be surrounded by less popular
hotspots, but the existence of less popular hotspots is inhibited in regions
with a large number of popular hotspots. We use the terms hierarchical
accompany and inhibiting patterns for these two spatial configurations.
Finally, to uncover the underlying mechanism, a KNN-based model is proposed to
reproduce the spatial distribution of other less popular hotspots according to
the most popular ones. These findings help decision-makers construct reasonable
urban minimum units for precise traffic and disease control, as well as plan a
more humane spatial arrangement of points of interest
Comprehensive Network Analysis Reveals Alternative Splicing-Related lncRNAs in Hepatocellular Carcinoma
© Copyright © 2020 Wang, Wang, Bhat, Chen, Xu, Mo, Yi and Zhou. It is increasingly appreciated that long non-coding RNAs (lncRNAs) associated with alternative splicing (AS) could be involved in aggressive hepatocellular carcinoma. Although many recent studies show the alteration of RNA alternative splicing by deregulated lncRNAs in cancer, the extent to which and how lncRNAs impact alternative splicing at the genome scale remains largely elusive. We analyzed RNA-seq data obtained from 369 hepatocellular carcinomas (HCCs) and 160 normal liver tissues, quantified 198,619 isoform transcripts, and identified a total of 1,375 significant AS events in liver cancer. In order to predict novel AS-associated lncRNAs, we performed an integration of co-expression, protein-protein interaction (PPI) and epigenetic interaction networks that links lncRNA modulators (such as splicing factors, transcript factors, and miRNAs) along with their targeted AS genes in HCC. We developed a random walk-based multi-graphic (RWMG) model algorithm that prioritizes functional lncRNAs with their associated AS targets to computationally model the heterogeneous networks in HCC. RWMG shows a good performance evaluated by the ROC curve based on cross-validation and bootstrapping strategies. As a conclusion, our robust network-based framework has derived 31 AS-related lncRNAs that not only validates known cancer-associated cases MALAT1 and HOXA11-AS, but also reveals new players such as DNM1P35 and DLX6-AS1with potential functional implications. Survival analysis further provides insights into the clinical significance of identified lncRNAs
Learning by Doing: An Online Causal Reinforcement Learning Framework with Causal-Aware Policy
As a key component to intuitive cognition and reasoning solutions in human
intelligence, causal knowledge provides great potential for reinforcement
learning (RL) agents' interpretability towards decision-making by helping
reduce the searching space. However, there is still a considerable gap in
discovering and incorporating causality into RL, which hinders the rapid
development of causal RL. In this paper, we consider explicitly modeling the
generation process of states with the causal graphical model, based on which we
augment the policy. We formulate the causal structure updating into the RL
interaction process with active intervention learning of the environment. To
optimize the derived objective, we propose a framework with theoretical
performance guarantees that alternates between two steps: using interventions
for causal structure learning during exploration and using the learned causal
structure for policy guidance during exploitation. Due to the lack of public
benchmarks that allow direct intervention in the state space, we design the
root cause localization task in our simulated fault alarm environment and then
empirically show the effectiveness and robustness of the proposed method
against state-of-the-art baselines. Theoretical analysis shows that our
performance improvement attributes to the virtuous cycle of causal-guided
policy learning and causal structure learning, which aligns with our
experimental results
Exploratory spatial data analysis for the identification of risk factors to birth defects
BACKGROUND: Birth defects, which are the major cause of infant mortality and a leading cause of disability, refer to "Any anomaly, functional or structural, that presents in infancy or later in life and is caused by events preceding birth, whether inherited, or acquired (ICBDMS)". However, the risk factors associated with heredity and/or environment are very difficult to filter out accurately. This study selected an area with the highest ratio of neural-tube birth defect (NTBD) occurrences worldwide to identify the scale of environmental risk factors for birth defects using exploratory spatial data analysis methods. METHODS: By birth defect registers based on hospital records and investigation in villages, the number of birth defects cases within a four-year period was acquired and classified by organ system. The neural-tube birth defect ratio was calculated according to the number of births planned for each village in the study area, as the family planning policy is strictly adhered to in China. The Bayesian modeling method was used to estimate the ratio in order to remove the dependence of variance caused by different populations in each village. A recently developed statistical spatial method for detecting hotspots, Getis's [Image: see text] [7], was used to detect the high-risk regions for neural-tube birth defects in the study area. RESULTS: After the Bayesian modeling method was used to calculate the ratio of neural-tube birth defects occurrences, Getis's [Image: see text] statistics method was used in different distance scales. Two typical clustering phenomena were present in the study area. One was related to socioeconomic activities, and the other was related to soil type distributions. CONCLUSION: The fact that there were two typical hotspot clustering phenomena provides evidence that the risk for neural-tube birth defect exists on two different scales (a socioeconomic scale at 6.84 km and a soil type scale at 22.8 km) for the area studied. Although our study has limited spatial exploratory data for the analysis of the neural-tube birth defect occurrence ratio and for finding clues to risk factors, this result provides effective clues for further physical, chemical and even more molecular laboratory testing according to these two spatial scales
Precise Measurements of Branching Fractions for Meson Decays to Two Pseudoscalar Mesons
We measure the branching fractions for seven two-body decays to
pseudo-scalar mesons, by analyzing data collected at
GeV with the BESIII detector at the BEPCII collider. The branching fractions
are determined to be ,
,
,
,
,
,
,
where the first uncertainties are statistical, the second are systematic, and
the third are from external input branching fraction of the normalization mode
. Precision of our measurements is significantly improved
compared with that of the current world average values
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