5,391 research outputs found
Development of the vestibular system
This review mainly focuses on the development of the vestibular system in humans and other mammals, but reference is made to anurans and other species where applicable. In the first section, the steps involved in the development of undifferentiated cells into mature vestibular receptors are analysed. Available data indicate that in humans, maturation of the vestibular receptor and its afferent innervations involves a similar sequence of events as in other mammalian species. In the second section, morphological and physiological aspects of the maturation of the central vestibular system are presented. Undifferentiated neuron precursors have been identified in specific segregrated domains of the hindbrain neural tube, and these can develop into secondary vestibular neurons with unique properties. Several neuronal populations in the vestibulospinal and vestibulo-ocular pathways have been found to correlate with rhombomeric domains at early embryonic stages. In rodents, the vestibular system continues to develop postnatally in terms of morphology and function until it achieves its final form. The postnatal changes in the properties of vestibular nuclear neurons are chronologically matched with structural changes and serve to prime the development of vestibular-induced reflexes. Copyright © 2002 S. Karger AG, Basel.published_or_final_versio
An evaluation of logistics policy enablers between Taiwan and the UK
Purpose: This paper aims to empirically identify crucial international logistics policy enablers and to examine their impacts on logistics performance using survey data collected from 169 responding firms in Taiwan and 109 responding firms in the UK including logistics companies, freight forwarders, shipping companies, agencies and airline companies.
Design/methodology/approach: A multiple regression analysis is used as a method to empirically validate the research model.
Findings: Results indicate the five most important logistics policy enablers according to Taiwanese logistics firms are information technology system, inland transport linkage, simplifying the customs clearance procedures, ports and maritime transport and having a policy to ensure efficient service operation and multiplicity of services. In contrast, for the UK logistics firms, the five most important logistics policy enablers are telecommunications, information technology system, avoidance of unnecessary regulation, inland transport linkage and ports and maritime transport. Results also indicate that logistics policy dimensions in terms of regulation, integration, infrastructure and logistics education have a positive influence on firms’ logistics service quality and efficiency.
Originality/value: Theoretical and policy implications from the research findings on logistics policy between these two countries are discussed in this paper
Effects of annealing temperature on sensing properties of Pt/HfO2/SiC Schottky-diode hydrogen sensor
Hafnium oxide (HfO 2) is successfully used as gate insulator for fabricating Metal-Insulator-SiC (MISiC) Schottky-diode hydrogen sensor. Sensors undergone N 2 annealing at different temperatures are fabricated for investigation. The hydrogen-sensing properties of these samples are compared with each other by taking the measurements at high temperature under various hydrogen concentrations using a computer-controlled measurement system. Experimental results show that sensitivity increases with the annealing temperature. Higher annealing temperature can enhance the densification of the HfO 2 film; improve the oxide stoichiometry; and facilitate the growth of a SiO 2 interfacial layer to give better interface quality, thus causing a remarkable reduction of the current of the sensor under air ambient. The effects of hydrogen adsorption on the barrier height and hydrogen-reaction kinetics are also investigated. © 2008 IEEE.published_or_final_versio
Enhanced sensing performance of MISiC schottky-diode hydrogen sensor by using HfON as gate insulator
MISiC Schottky-diode hydrogen sensor with HfON gate insulator fabricated by NO nitridation is investigated. The hydrogen-sensing characteristics of this novel sensor are studied by doing steady-state and transient measurements at different temperatures and hydrogen concentrations using a computer-controlled measurement system. Experimental results show that this novel sensor can rapidly respond to hydrogen variation and can give a significant response even at a low H 2 concentration of 48-ppm, e.g., a sensitivity of 81% is achieved at 450°C and 2.5 V, which is two times higher than its HfO 2 counterpart. The enhanced sensitivity of the device should be attributed to a remarkable reduction of the current of the sensor before hydrogen exposure by the NO nitridation because the NO nitridation can passivate the O vacancies in the insulator and facilitate the formation of a SiO 2 interlayer to suppress the leakage current associated with high-k materials. © 2006 IEEE.published_or_final_versio
Improved Sensing Characteristics of a Novel Pt/HfTiO2/SiC Schottky-Diode Hydrogen Sensor
published_or_final_versio
Atorvastatin correlates with decreased risk of esophageal cancer: A population-based casecontrol study from Taiwan
Objectives: The aim of this study was to explore the association between the use of statins and esophageal cancer in Taiwan.Methods: We designed a casecontrol study using database from the Taiwan National Health Insurance program. In all, 549 patients (cases) aged 20 years or older diagnosed recently with esophageal cancer, from 2000 to 2009, and 2,196 subjects (controls) without esophageal cancer participated in this study. The association between esophageal cancer and the use of statins and other co-morbidities was measured.Results: After adjustment for covariates, multivariate logistic regression showed that patients with a cumulative duration of ]12 months of using atorvastatin might have a reduced risk of esophageal cancer, compared with those who did not use statins (odds ratio [OR] 0.14, 95% confidence interval [CI] 0.040.56). The other statins could not show a significant association with esophageal cancer. Age (OR 1.01, 95% CI 1.001.01), alcoholism (OR 3.83, 95% CI 3.014.89), and esophageal diseases (OR 4.60, 95% CI 3.466.12) were independent factors significantly associated with esophageal cancer.Conclusions: Use of atorvastatin ]12 months may correlate with an 86% reduction of esophageal cancer risk.Keywords: atorvastatin; esophageal cancer; stati
Atorvastatin correlates with decreased risk of esophageal cancer: A population-based casecontrol study from Taiwan
Objectives: The aim of this study was to explore the association between the use of statins and esophageal cancer in Taiwan.Methods: We designed a casecontrol study using database from the Taiwan National Health Insurance program. In all, 549 patients (cases) aged 20 years or older diagnosed recently with esophageal cancer, from 2000 to 2009, and 2,196 subjects (controls) without esophageal cancer participated in this study. The association between esophageal cancer and the use of statins and other co-morbidities was measured.Results: After adjustment for covariates, multivariate logistic regression showed that patients with a cumulative duration of ]12 months of using atorvastatin might have a reduced risk of esophageal cancer, compared with those who did not use statins (odds ratio [OR] 0.14, 95% confidence interval [CI] 0.040.56). The other statins could not show a significant association with esophageal cancer. Age (OR 1.01, 95% CI 1.001.01), alcoholism (OR 3.83, 95% CI 3.014.89), and esophageal diseases (OR 4.60, 95% CI 3.466.12) were independent factors significantly associated with esophageal cancer.Conclusions: Use of atorvastatin ]12 months may correlate with an 86% reduction of esophageal cancer risk.Keywords: atorvastatin; esophageal cancer; stati
Combinatorics of linear iterated function systems with overlaps
Let be points in , and let
be a one-parameter family of similitudes of : where
is our parameter. Then, as is well known, there exists a
unique self-similar attractor satisfying
. Each has
at least one address , i.e.,
.
We show that for sufficiently close to 1, each has different
addresses. If is not too close to 1, then we can still have an
overlap, but there exist 's which have a unique address. However, we
prove that almost every has addresses,
provided contains no holes and at least one proper overlap. We
apply these results to the case of expansions with deleted digits.
Furthermore, we give sharp sufficient conditions for the Open Set Condition
to fail and for the attractor to have no holes.
These results are generalisations of the corresponding one-dimensional
results, however most proofs are different.Comment: Accepted for publication in Nonlinearit
Prospects for Detection of Exoplanet Magnetic Fields Through Bow-Shock Observations During Transits
An asymmetry between the ingress and egress times was observed in the near-UV
light curve of the transit planet WASP-12b. Such asymmetry led us to suggest
that the early ingress in the UV light curve of WASP-12b, compared to the
optical observations, is caused by a shock around the planet, and that shocks
should be a common feature in transiting systems. Here, we classify all the
transiting systems known to date according to their potential for producing
shocks that could cause observable light curve asymmetries. We found that 36/92
of known transiting systems would lie above a reasonable detection threshold
and that the most promising candidates to present shocks are: WASP-19b,
WASP-4b, WASP-18b, CoRoT-7b, HAT-P-7b, CoRoT-1b, TrES-3, and WASP-5b. For
prograde planets orbiting outside the co-rotation radius of fast rotating
stars, the shock position, instead of being ahead of the planetary motion as in
WASP-12b, trails the planet. In this case, we predict that the light curve of
the planet should present a late-egress asymmetry. We show that CoRoT-11b is a
potential candidate to host such a behind shock and show a late egress. If
observed, these asymmetries can provide constraints on planetary magnetic
fields. For instance, for a planet that has a magnetic field intensity similar
to Jupiter's field (~ 14 G) orbiting a star whose magnetic field is between 1
and 100G, the stand-off distance between the shock and the planet, which we
take to be the size of the planet's magnetosphere, ranges from 1 to 40
planetary radii.Comment: 7 pages (including the complete version of Table 1), 2 Tables, 3
Figures. Accepted by MNRAS Letter
Effects of sputtering and annealing temperatures on MOS capacitor with HfTiON gate dielectric
In this work, Al/HfTiON/n-Si capacitors with different sputtering and annealing temperatures are studied. Larger accumulation capacitance and flat-band voltage are observed for samples with higher sputtering or post-deposition annealing temperature. Gate conduction mechanisms are only affected by sputtering temperature slightly. The flat-band voltage shift and interface-state density at midgap under high-field gate injection and substrate injection are investigated, and the results imply electron detrapping in the gate dielectric. ©2009 IEEE.published_or_final_versionThe IEEE International Conference of Electron Devices and Solid-State Circuits (EDSSC 2009), Xi'an, China, 25-27 December 2009. In Proceedings of EDSSC, 2009, p. 209-21
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