180 research outputs found
On Stein's Identity and Near-Optimal Estimation in High-dimensional Index Models
We consider estimating the parametric components of semi-parametric multiple
index models in a high-dimensional and non-Gaussian setting. Such models form a
rich class of non-linear models with applications to signal processing, machine
learning and statistics. Our estimators leverage the score function based first
and second-order Stein's identities and do not require the covariates to
satisfy Gaussian or elliptical symmetry assumptions common in the literature.
Moreover, to handle score functions and responses that are heavy-tailed, our
estimators are constructed via carefully thresholding their empirical
counterparts. We show that our estimator achieves near-optimal statistical rate
of convergence in several settings. We supplement our theoretical results via
simulation experiments that confirm the theory
Reduction of urate crystal-induced inflammation by root extracts from traditional oriental medicinal plants: elevation of prostaglandin D2 levels
Dried roots of the plants Acanthopanax senticosus, Angelica sinensis and Scutellaria baicalensis are used in traditional oriental medicine and reportedly possess anti-inflammatory properties. Using the murine air pouch model of inflammation, we investigated the efficacy and mode of action of an extract from these three plants in crystal-induced inflammation. Air pouches were raised on the backs of 8-week-old BALB/c mice. Mice were fed 100 mg/kg body weight of root extracts (A. senticosus:A. sinensis:S. baicalensis mixed in a ratio of 5:4:1 by weight) or vehicle only on days 3–6. Inflammation was elicited on day 6 by injecting 2 mg of monosodium urate (MSU) crystals into the pouch. Neutrophil density and IL-6 and TNF-α mRNA levels were determined in the pouch membrane, and the leukocyte count and IL-6, prostaglandin E2 (PGE2) and prostaglandin D2 (PGD2) levels were determined in the pouch exudate. Treatment with the root extracts led to a reduction in all inflammatory parameters: the leukocyte count in the pouch exudate decreased by 82%; the neutrophil density in the pouch membrane decreased by 68%; IL-6 and TNF-α mRNA levels in the pouch membrane decreased by 100%; the IL-6 concentration in the pouch fluid decreased by 50%; and the PGE2 concentration in the pouch fluid decreased by 69%. Remarkably, the concentration of the potentially anti-inflammatory PGD2 rose 5.2-fold in the pouch exudate (p < 0.005), which led to a normalization of the PGD2:PGE2 ratio. A 3.7-fold rise in hematopoietic PGD synthase (h-PGDS) mRNA paralleled this rise in PGD2 (p = 0.01)
The System That Cried Wolf: Sensor Security Analysis of Wide-area Smoke Detectors for Critical Infrastructure
Fire alarm and signaling systems are a networked system of fire detectors, fire control units, automated fire extinguishers, and fire notification appliances. Malfunction of these safety-critical cyber-physical systems may lead to chaotic evacuations, property damages, and even loss of human life. Therefore, reliability is one of the most crucial factors for fire detectors. Indeed, even a single report of a fire cannot be ignored considering the importance of early fire detection and suppression. In this paper, we show that wide-area smoke detectors, which are globally installed in critical infrastructures such as airports, sports facilities, and auditoriums, have significant vulnerabilities in terms of reliability; one can remotely and stealthily induce false fire alarms and suppress real fire alarms with a minimal attacker capability using simple equipment. The practicality and generalizability of these vulnerabilities has been assessed based on the demonstration of two types of sensor attacks on two commercial-off-the-shelf optical beam smoke detectors from different manufacturers. Further, the practical considerations of building stealthy attack equipment has been analyzed, and an extensive survey of almost all optical beam smoke detectors on the market has been conducted.
In addition, we show that the current standards of the fire alarm network connecting the detector and a control unit exacerbate the problem, making it impossible or very difficult to mitigate the threats we found. Finally, we discuss hardware and software-based possible countermeasures for both wide-area smoke detectors and the fire alarm network; the effectiveness of one of the countermeasures is experimentally evaluated
COVID-19 Perception, Knowledge, and Preventive Practice: Comparison between South Korea, Ethiopia, and Democratic Republic of Congo
In Africa, the first confirmed case of COVID-19 was reported in Egypt on February 14, 2020. Since then, the number of cases has continued to increase with Ethiopia, the Democratic Republic of Congo (DRC), Nigeria, Sudan, Angola, Tanzania, Ghana, and Kenya identified as vulnerable countries. The present study aimed to: 1) identify differences in trust level of COVID-19 diagnosis, recent healthcare utilization experiences, and COVID-19-related knowledge, information, and prevention practices in South Korea, Ethiopia, and DRC; and 2) identify factors influencing trust level in healthcare facilities regarding COVID-19 diagnosis. The present study was cross-sectional. The questionnaire survey was conducted between May 1–14, 2020 using Google forms, and 748 respondents were included in the final analysis. The data collected were analyzed using ANOVA, post - hoc test, and binary logistic regression analysis. South Korea showed higher rate of practice for COVID-19 prevention such as hand washing, mask wearing, and etc. than Ethiopia and DRC. The results showed significant differences with the trust level being 3.129 times higher in respondents from DRC than those from Ethiopia (aOR=3.129, 95% CI: [1.884-5.196], p<.000) and 29.137 times higher in respondents from South Korean than those from Ethiopia (aOR=29.137, 95% CI: [13.869-61.210], p<.000). Gender, age, number of family members, healthcare utilization experience, information, and practice were significant variables. Health education expansion for information and practice about COVID-19 in Ethiopia and DRC is necessary.
Keywords: COVID-19, Pandemic, Ethiopia, DRC, South Korea, Online Survey
En Afrique, le premier cas confirmé de COVID-19 a été signalé en Égypte le 14 février 2020. Depuis, le nombre de cas n'a cessé d'augmenter avec l'Éthiopie, la République démocratique du Congo (RDC), le Nigéria, le Soudan, l'Angola, La Tanzanie, le Ghana et le Kenya ont été identifiés comme pays vulnérables. La présente étude visait à : 1) identifier les différences de niveau de confiance dans le diagnostic du COVID-19, les expériences récentes d'utilisation des soins de santé et les connaissances, informations et pratiques de prévention liées au COVID-19 en Corée du Sud, en Éthiopie et en RDC; et 2) identifier les facteurs influençant le niveau de confiance dans les établissements de santé concernant le diagnostic du COVID-19. La présente étude était transversale. L'enquête par questionnaire a été menée du 1er au 14 mai 2020 à l'aide de formulaires Google, et 748 répondants ont été inclus dans l'analyse finale. Les données collectées ont été analysées en utilisant une analyse ANOVA, un test post-hoc et une analyse de régression logistique binaire. La Corée du Sud a montré un taux de pratique plus élevé pour la prévention du COVID-19, comme le lavage des mains, le port d'un masque, etc. que l'Éthiopie et la RDC. Les résultats ont montré des différences significatives, le niveau de confiance étant 3,129 fois plus élevé chez les répondants de RDC que chez ceux d'Éthiopie (aOR = 3,129, IC à 95%: [1,884-5,196], p <.000) et 29,137 fois plus élevé chez les répondants sud-coréens que ceux d'Éthiopie (aOR = 29,137, IC à 95%: [13,869-61,210], p <.000). Le sexe, l'âge, le nombre de membres de la famille, l'expérience d'utilisation des soins de santé, l'information et la pratique étaient des variables importantes. L'élargissement de l'éducation sanitaire pour l'information et la pratique du COVID-19 en Éthiopie et en RDC est nécessaire.
Mots-clés: COVID-19, Pandémie, Éthiopie, RDC, Corée du Sud, Enquête en lign
Mode Suppressed TEM Cell Design for High Frequency IC Measurements
TEM cells or GTEM cells can be used to evaluate the radiated emissions of integrated circuits (ICs). The applicable frequency bandwidth of a TEM cell is limited due to the resonances of higher order modes. This paper describes how a TEM cell can be modified to extend the frequency range without changing the test topology. Several methods are proposed and implemented to suppress the higher order modes. The magnetic field coupling and electric field coupling are evaluated for the new design. The frequency bandwidth of the modified TEM cell is extended from original 1 GHz to 2.5 GHz
Mori Folium and Mori Fructus Mixture Attenuates High-Fat Diet-Induced Cognitive Deficits in Mice
Obesity has become a global health problem, contributing to various diseases including diabetes, hypertension, cancer, and dementia. Increasing evidence suggests that obesity can also cause neuronal damage, long-term memory loss, and cognitive impairment. The leaves and the fruits of Morus alba L., containing active phytochemicals, have been shown to possess antiobesity and hypolipidemic properties. Thus, in the present study, we assessed their effects on cognitive functioning in mice fed a high-fat diet by performing immunohistochemistry, using antibodies against c-Fos, synaptophysin, and postsynaptic density protein 95 and a behavioral test. C57BL/6 mice fed a high-fat diet for 21 weeks exhibited increased body weight, but mice coadministered an optimized Mori Folium and Mori Fructus extract mixture (2 : 1; MFE) for the final 12 weeks exhibited significant body weight loss. Additionally, obese mice exhibited not only reduced neural activity, but also decreased presynaptic and postsynaptic activities, while MFE-treated mice exhibited recovery of these activities. Finally, cognitive deficits induced by the high-fat diet were recovered by cotreatment with MFE in the novel object recognition test. Our findings suggest that the antiobesity effects of MFE resulted in recovery of the cognitive deficits induced by the high-fat diet by regulation of neural and synaptic activities
Skeletal muscle mass to visceral fat area ratio as a predictor of nonalcoholic fatty liver disease in lean and overweight men and women with effect modification by sex
Long or irregular menstrual cycles and risk of prevalent and incident non-alcoholic fatty liver disease
Fasting ketonuria is inversely associated with coronary artery calcification in non-diabetic individuals
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