Multiscale time series modelling with an application to the relativistic electron intensity at the geosynchronous orbit

In this paper, a Bayesian system identification approach to multiscale time series modelling is proposed, where multiscale means that the output of the system is observed at one(coarse) resolution while the input of the system is observed at another (One) resolution. The proposed method identifies linear models at different levels of resolution where the link between the two resolutions is realised via non-overlapping averaging process. This averaged time series at the coarse level of resolution is assumed to be a set of observations from an implied process so that the implied process and the output of the system result in an errors-in-variables ARMAX model at the coarse level of resolution. By using a Bayesian inference and Markov Chain Monte Carlo (MCMC) method, such a modelling framework results in different dynamical models at different levels of resolution at the same time. The new method is also shown to have the ability to combine information across different levels of resolution. An application to the analysis of the relativistic electron intensity at the geosynchronous orbit is used to illustrate the new method

Biophysical modelling of a drosophila photoreceptor

It remains unclear how visual information is co-processed by different layers of neurons in the retina. In particular, relatively little is known how retina translates vast environmental light changes into neural responses of limited range. We began examining this question in a bottom-up way in a relatively simple °y eye. To gain understanding of how complex bio-molecular interactions govern the conversion of light input into voltage output (phototransduction), we are building a biophysical model of the Drosophila R1-R6 photoreceptor. Our model, which relates molecular dynamics of the underlying biochemical reactions to external light input, attempts to capture the molecular dynamics of phototransduction gain control in a quantitative way

Kinetic description of avalanching systems

Avalanching systems are treated analytically using the renormalization group (in the self-organized-criticality regime) or mean-field approximation, respectively. The latter describes the state in terms of the mean number of active and passive sites, without addressing the inhomogeneity in their distribution. This paper goes one step further by proposing a kinetic description of avalanching systems making use of the distribution function for clusters of active sites. We illustrate application of the kinetic formalism to a model proposed for the description of the avalanching processes in the reconnecting current sheet of the Earth magnetosphere.Comment: 9 page

El complejo karstico-yesifero subterráneo "Pedro Fernández" (Estremera, provincia de Madrid)

[Resumen] Se han analizado los factores originales de este morfosistema kárstico subterraneo, detallan do los procesos responsables de su génesis, así como la morfolmgía interior. Diferenciando los tipos de galerias y su evolución. Al mismo tiempo, se aportan determinadas consideraciones acerca de la sedimentación interior de la cavidad, su tipología e interpretación de su significado[Resumé] On a analysé les facteurs qui ont originé ce morphosysthéme karstique souterrain, en detallant le procesus responsable de leur genére, ainsi que leur morphilogie intérieure. En distinguant les types de galeries et leur évolution. Eu méme temps, on apporte certaines considerations données á propos de la sédimentation, sa typologie et interprétation de sa signification

Ace inhibition and cardiovascular mortality and morbidity in essential hypertension: The end of the search or a need for further investigations?

Scientific evidence currently available supports the concept that renin-angiotensin blockade with angiotensin converting enzyme inhibitors as a first-line treatment exhibits in arterial hypertension beneficial effects in the prevention of mortality and morbidity comparable to those achieved with diuretics and β-blockers. In addition, the renin-angiotensin blockade has also proved to be beneficial in the secondary prevention of several complications of hypertensive disease such as after myocardial infarction and congestive heart failure, as well as in the prevention of the incidence of type 2 diabetes, and the progression of diabetic and nondiabetic nephropathy. In this later regard, recent evidence with angiotensin II receptor antagonists in reducing the progression of nephropathy in type 2 diabetes strongly confirms that antagonism of the renin-angiotensin system is an effective approach to cardiovascular and renal disease. Finally, the renin-angiotensin blockade in high-risk patients may reduce cardiovascular mortality independently of the effect on blood pressure (BP). The effect of other antihypertensive drugs on cardiovascular risk in patients with high-normal BP should be investigated to establish whether they exhibit a comparable effect or whether there is a class-related benefit of drugs blocking the renin-angiotensin system. Such a strategy could also be encouraged to design future interventional studies with the newer classes of compounds (angiotensin II AT1-receptor antagonists, vasopeptidase inhibitors, endothelin antagonists), which would have the additional potential advantage of providing information more easily transferable to large-scale clinical practice. Am J Hypertens 2002;15:367-371 © 2002 American Journal of Hypertension, Lt

Four New Delta Scuti Pulsators from a Variability Survey of 131 Stars

In a photometric variability survey of 131 stars with B < 14 mag, we have found four new Delta Scuti stars. We were sensitive to oscillation amplitudes as low as a few mmag. The detection rate of short-period (P < 0.1 d) pulsating variable stars, which may be relevant for planned large variability surveys such as GAIA, POI, and even the LSST, was therefore 3%. All four new variable stars have low pulsation amplitude (tens of mmag), and one has a very short period (0.0198 d). This star is one of the fastest known Delta Scuti pulsators. The short period of this variable star makes it observationally tractable, and it may therefore be a particularly good candidate for asteroseismological studies. All four new variable stars will add to the cadre of low-amplitude and relatively short-period Delta Scuti stars that are potentially useful for learning about the structure of stars on or near the main sequence, slightly more massive than the Sun.Comment: To appear in the June 2002 issue of PASP, 9 pages, 6 figure

Inhibition of hyaluronidase activity by high-pressure treated onion

Onions exert their effects on human health via multiple different functions, including antioxidant, antiinflammatory, and antibacterial properties. Upregulation of hyaluronidase activity occurs in chronic inflammatory conditions. High hydrostatic pressure food processing offers the chance of producing functional foods, in the sense that not only preserve the nutritional, microbiological and sensorial quality of foods, but also can improve the extraction of potentially health-related compounds due to the effects of this technology on plant food structure. Onions are a good source of bioactive compounds, such as phenolic compounds and organosulfur compounds, which have been related to beneficial health effects mainly due to their antioxidant and antiinflammatory properties. In this study we evaluated the ability of onion treated by highpressure to inhibit in vitro hyaluronidase activity, as an in vitro measurement of its antiinflammatory activity.Peer Reviewe

Trends in Mortality and Medical Spending in Patients Hospitalized for Community-Acquired Pneumonia: 1993–2005

Background: Community-acquired pneumonia (CAP) is the most common infectious cause of death in the United States. To understand the impact of efforts to improve quality and efficiency of care in CAP, we examined trends in mortality and costs among hospitalized CAP patients. Methods: Using the National Inpatient Sample from 1993–2005, we studied 569,524 CAP admissions. The primary outcome was mortality at discharge. We used logistic regression to evaluate the mortality trend, adjusting for age, gender, and comorbidities. To account for the impact of early discharge practices, we also compared daily mortality rates and performed a Cox proportional-hazards model. We used a generalized linear model to analyze trends in hospitalization costs, which were derived using cost-to-charge ratios. Results: Over time, length of stay (LOS) declined, while more patients were discharged to other facilities. The frequency of many comorbidities increased. Age/gender-adjusted mortality decreased from 8.9% to 4.1% (P < 0.001). In multivariable analysis, the mortality risk declined through 2005 (odds ratio, 0.50; 95% confidence interval [CI], 0.48–0.53), compared to reference year 1993. The daily mortality rates demonstrated that most of the mortality reduction occurred early during hospitalization. After adjusting for early discharge practices, the risk of mortality still declined through 2005 (hazard ratio, 0.74, 95% CI 0.70–0.78). Median hospitalization costs exhibited a modest reduction over time, mostly due to reduced LOS. Conclusions: Mortality among patients hospitalized for CAP has declined. Lower in-hospital mortality at a reduced cost suggests that pneumonia is a case of improved productivity in health care.Economic

Data production models for the CDF experiment

The data production for the CDF experiment is conducted on a large Linux PC farm designed to meet the needs of data collection at a maximum rate of 40 MByte/sec. We present two data production models that exploits advances in computing and communication technology. The first production farm is a centralized system that has achieved a stable data processing rate of approximately 2 TByte per day. The recently upgraded farm is migrated to the SAM (Sequential Access to data via Metadata) data handling system. The software and hardware of the CDF production farms has been successful in providing large computing and data throughput capacity to the experiment.Comment: 8 pages, 9 figures; presented at HPC Asia2005, Beijing, China, Nov 30 - Dec 3, 200