2,030 research outputs found
Quantile regression with varying coefficients
Quantile regression provides a framework for modeling statistical quantities
of interest other than the conditional mean. The regression methodology is well
developed for linear models, but less so for nonparametric models. We consider
conditional quantiles with varying coefficients and propose a methodology for
their estimation and assessment using polynomial splines. The proposed
estimators are easy to compute via standard quantile regression algorithms and
a stepwise knot selection algorithm. The proposed Rao-score-type test that
assesses the model against a linear model is also easy to implement. We provide
asymptotic results on the convergence of the estimators and the null
distribution of the test statistic. Empirical results are also provided,
including an application of the methodology to forced expiratory volume (FEV)
data.Comment: Published at http://dx.doi.org/10.1214/009053606000000966 in the
Annals of Statistics (http://www.imstat.org/aos/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Quality characteristics of rice inoculated with Inonotus obliquus mycelia and incubated under different cultivating conditions
This study was performed to investigate the quality characteristics of Inonotus obliquus mycelia rice incubated with I. obliquus (KCTC 256152). Different volumes of mycelial culture of I. obliquus were used for production of I. obliquus mycelia rice. Twenty percent of the mycelial culture was added to rice and designated as IOR-20, 30% as IOR-30 and 40% as IOR-40. Using the I. obliquus mycelia rice, the contents of β-1,3-glucan, betulin, total polyphenol and 1,1-diphenyl-2-picrylhydrazol (DPPH) radical scavenging activity, Hunter`s color values, free amino acid content, and mineral content were investigated. The β-1,3-glucan content in I. obliquus mycelia rice were in the order of IOR-30(729.7 μg/g) > IOR-20(716.0 μg/g) > IOR-40(690.5 μg/g) and those of betulin content were OR-30(1273.7 μg/g) > IOR-40 (1247.81 μg/g) > IOR-20 (1209.82 μg/g). The highest content of total polyphenols (353.6 μg/g) and activity of DPPH radical scavenging were observed in the IOR-30. The higher contents for β-1,3-glucan, betulin, polyphenol, and DPPH radical scavenging were found in 30% mycelial culture treatment, showing the best condition for the production of I. obliquus mycelia. Aspartic acid (10.28 to 29.44 μg/100 g), threonine (5.43 to 11.00 μg/100 g), serine (8.84 to 14.53 μg/100 g), glutamic acid (31.01 to 53.61 μg/100 g), glycine (4.77 to 10.26 μg/100 g), valine (2.93 to 6.57 μg/100 g), and lysine (5.20 to 14.41 μg/100 g) contents were determined in the I. obliquus mycelia rice and the order was as follows; IOR-20>IOR-30>IOR-40. The IOR-30 sample exhibited the highest levels of K(899.1±8.1 mg/kg), Mg(427.3±9.3 mg/kg), Ca(480.2±6.9 mg/kg), Na(296.1±9.2 mg/kg).Keywords: Rice, Inonotus obliquus (KCTC 256152), β-1,3-glucan, betulin, quality characteristicsAfrican Journal of Biotechnology Vol. 12(33), pp. 5131-513
A Brief Tutorial on Sample Size Calculations for Fairness Audits
In fairness audits, a standard objective is to detect whether a given
algorithm performs substantially differently between subgroups. Properly
powering the statistical analysis of such audits is crucial for obtaining
informative fairness assessments, as it ensures a high probability of detecting
unfairness when it exists. However, limited guidance is available on the amount
of data necessary for a fairness audit, lacking directly applicable results
concerning commonly used fairness metrics. Additionally, the consideration of
unequal subgroup sample sizes is also missing. In this tutorial, we address
these issues by providing guidance on how to determine the required subgroup
sample sizes to maximize the statistical power of hypothesis tests for
detecting unfairness. Our findings are applicable to audits of binary
classification models and multiple fairness metrics derived as summaries of the
confusion matrix. Furthermore, we discuss other aspects of audit study designs
that can increase the reliability of audit results.Comment: 4 pages, 1 figure, 1 table, Workshop on Regulatable Machine Learning
at the 37th Conference on Neural Information Processing System
Cognitive and behavioral effects of lamotrigine and carbamazepine monotherapy in patients with newly diagnosed or untreated partial epilepsy
AbstractPurposeIn this prospective study, we compared the long-term cognitive and behavioral effects of lamotrigine (LTG) and carbamazepine (CBZ) in patients with newly diagnosed or untreated partial epilepsy.MethodsThis was a multicenter, open-label, randomized study that compared monotherapy with LTG and CBZ in newly diagnosed or untreated patients with partial epilepsy. We employed an 8-week titration period and a 40-week maintenance period. Neuropsychological tests, Symptom Check List-90, and QOLIE-31 were assessed at baseline, 16 weeks, and 48 weeks after drug treatment. A group-by-time interaction was the primary outcome measure and was analyzed by use of the linear mixed model.ResultsA total of 110 patients were eligible and 73 completed the 48-week study (LTG, n=39; CBZ, n=34). Among the cognitive tests, significant group-by-time interaction was identified only in phonemic fluency of Controlled Oral Word Association Task (p=0.0032) and Stroop Color–Word Interference (p=0.0283), with a significant better performance for LTG group. All other neuropsychological tests included did not show significant group-by-time interactions. Among the subscales of Symptom Check List-90, significant group-by-time interactions were identified in Obsessive-Compulsive (p=0.0005), Paranoid Ideation (p=0.0454), Global Severity Index (p=0.0194), and Positive Symptom Total (p=0.0197), with a significant improvement for CBZ group. QOLIE-31 did not show significant group-by-time interactions.ConclusionOur data suggest that epilepsy patients on LTG have better performance on phonemic fluency and the task of Stroop Color–Word Interference than do patients on CBZ, whereas patients on CBZ had more favorable behavioral effects on two subscales and two global scores of Symptom Check List-90 than did patients on LTG
Dual quadratic differentials and entire minimal graphs in Heisenberg space
We define holomorphic quadratic differentials for spacelike surfaces with
constant mean curvature in the Lorentzian homogeneous spaces
with isometry group of dimension 4, which are dual to
the Abresch-Rosenberg differentials in the Riemannian counterparts
, and obtain some consequences. On the one hand, we
give a very short proof of the Bernstein problem in Heisenberg space, and
provide a geometric description of the family of entire graphs sharing the same
differential in terms of a 2-parameter conformal deformation. On the other
hand, we prove that entire minimal graphs in Heisenberg space have negative
Gauss curvature.Comment: 19 page
Autonomous control of terminal erythropoiesis via physical interactions among erythroid cells
AbstractIn vitro erythropoiesis has been studied extensively for its application in the manufacture of transfusable erythrocytes. Unfortunately, culture conditions have not been as effective as in vivo growth conditions, where bone marrow macrophages are known to be a key regulator of erythropoiesis. This study focused on the fact that some erythroblasts are detached from macrophages and only contact other erythroblasts. We hypothesized that additional factors regulate erythroblasts, likely through either physical contact or secreted factors. To further elucidate these critical factors, human erythroblasts derived from cord blood were cultured at high density to mimic marrow conditions. This growth condition resulted in a significantly increased erythroid enucleation rate and viability. We found several novel contact-related signals in erythroblasts: intercellular adhesion molecule-4 (ICAM-4) and deleted in liver cancer-1 (DLC-1). DLC-1, a Rho-GTPase-activating protein, has not previously been reported in erythroid cells, but its interaction with ICAM-4 was demonstrated here. We further confirmed the presence of a secreted form of human ICAM-4 for the first time. When soluble ICAM-4 was added to media, cell viability and enucleation increased with decreased nuclear dysplasia, suggesting that ICAM-4 is a key factor in contact between cells. These results highlight potential new mechanisms for autonomous control of erythropoiesis. The application of these procedures to erythrocyte manufacturing could enhance in vitro erythrocyte production for clinical use
Principles of cerebral hemodynamics when intracranial pressure is raised: lessons from the peripheral circulation.
BACKGROUND: The brain is highly vascular and richly perfused, and dependent on continuous flow for normal function. Although confined within the skull, pressure within the brain is usually less than 15 mmHg, and shows small pulsations related to arterial pulse under normal circumstances. Pulsatile arterial hemodynamics in the brain have been studied before, but are still inadequately understood, especially during changes of intracranial pressure (ICP) after head injury. METHOD: In seeking cohesive explanations, we measured ICP and radial artery pressure (RAP) invasively with high-fidelity manometer systems, together with middle cerebral artery flow velocity (MCAFV) (transcranial Doppler) and central aortic pressure (CAP) generated from RAP, using a generalized transfer function technique, in eight young unconscious, ventilated adults following closed head trauma. We focused on vascular effects of spontaneous rises of ICP ('plateau waves'). RESULTS: A rise in mean ICP from 29 to 53 mmHg caused no consistent change in pressure outside the cranium, or in heart rate, but ICP pulsations increased in amplitude from 8 to 20 mmHg, and ICP waveform came to resemble that in the aorta. Cerebral perfusion pressure (=central aortic pressure - ICP), which equates with transmural pressure, fell from 61 to 36 mmHg. Mean MCAFV fell from 53 to 40 cm/s, whereas pulsatile MCAFV increased from 77 to 98 cm/s. These significant changes (all P < 0.01) may be explained using the Monro-Kellie doctrine, because of compression of the brain, as occurs in a limb when external pressure is applied. CONCLUSION: The findings emphasize importance of reducing ICP, when raised, and on the additional benefits of reducing wave reflection from the lower body.This study was supported by the National Institute of Health
Research, the Biomedical Research Centre (Neuroscience
Theme), and the Medical Research Council (Grants
G0600986 and G9439390). J.D.P. has received the NIHR
Investigator Awards. M.O.K. is sponsored by an Australian
Postgraduate Awards Industrial Linkage Grant from the
Australian Research Council (LP0884094), with AtCor
Medical Australia as the collaborating organization.This is the final version of the article. It first appeared from Wolters Kluwer via http://dx.doi.org/10.1097/HJH.000000000000053
3,3\u27-Diindolylmethane Augments 5-Fluorouracil-InducedGrowth Suppression in Gastric Cancer Cells through Suppression of the Akt/GSK-3β and WNT/Beta-Catenin
Gastric cancer (GC) is one of the most lethal cancers in South Korea, and it is a cancer of concern worldwide. 5-fluorouracil (5-Fu) is commonly used as the first-line therapy for advanced GC; however, its side effects often limit the dosage range and impair patients\u27 quality of life. Due to the limitations of current chemotherapy, new anticancer therapies are urgently needed. 3,3\u27-diindolylmethane (DIM) has been reported to have the ability to protect against various types of cancer. Our study aimed to elucidate the anticancer effect of DIM in GC when treated with the chemotherapeutic agent 5-Fu. In our results, combined treatment with DIM and 5-Fu resulted in higher apoptosis and lower cell proliferation than treatment with 5-Fu in SNU484 and SNU638 cell lines. Furthermore, when DIM and 5-Fu were administered together, cell invasion was diminished by mediated E-cadherin, MMP-9, and uPA; p-Akt and p-GSK-
Carcinoma Mixed within Milk of Calcium in a Breast: a Case Report
Milk of calcium located in the breast is typically a benign entity. However, carcinoma may incidentally arise adjacent to or even within milk of calcium. Consequently, the characteristics of all observed calcific particles should be carefully analyzed. In this study, we report a case of carcinoma presented as malignant microcalcifications mixed within milk of calcium in a breast
Comparative Genomics Reveals Adaptation by Alteromonas sp. SN2 to Marine Tidal-Flat Conditions: Cold Tolerance and Aromatic Hydrocarbon Metabolism
Alteromonas species are globally distributed copiotrophic bacteria in marine habitats. Among these, sea-tidal flats are distinctive: undergoing seasonal temperature and oxygen-tension changes, plus periodic exposure to petroleum hydrocarbons. Strain SN2 of the genus Alteromonas was isolated from hydrocarbon-contaminated sea-tidal flat sediment and has been shown to metabolize aromatic hydrocarbons there. Strain SN2's genomic features were analyzed bioinformatically and compared to those of Alteromonas macleodii ecotypes: AltDE and ATCC 27126. Strain SN2's genome differs from that of the other two strains in: size, average nucleotide identity value, tRNA genes, noncoding RNAs, dioxygenase gene content, signal transduction genes, and the degree to which genes collected during the Global Ocean Sampling project are represented. Patterns in genetic characteristics (e.g., GC content, GC skew, Karlin signature, CRISPR gene homology) indicate that strain SN2's genome architecture has been altered via horizontal gene transfer (HGT). Experiments proved that strain SN2 was far more cold tolerant, especially at 5°C, than the other two strains. Consistent with the HGT hypothesis, a total of 15 genomic islands in strain SN2 likely confer ecological fitness traits (especially membrane transport, aromatic hydrocarbon metabolism, and fatty acid biosynthesis) specific to the adaptation of strain SN2 to its seasonally cold sea-tidal flat habitat
- …