843 research outputs found
Estimates of patient costs related with population morbidity: Can indirect costs affect the results?
A number of health economics works require patient cost estimates as a basic information input. However the accuracy of cost estimates remains in general unspecified. We propose to investigate how the allocation of indirect costs or overheads can affect the estimation of patient costs in order to allow for improvements in the analysis of patient costs estimates. Instead of focusing on the costing method, this paper proposes to highlight changes in variance explained observed when a methodology is chosen. We compare three overhead allocation methods for a specific Spanish population adjusted using the Clinical Risk Groups (CRG), and we obtain different series of full-cost group estimates. As a result, there are significant gains in the proportion of the variance explained, depending upon the methodology used. Furthermore, we find that the global amount of variation explained by risk adjustment models depends mainly on direct costs and is independent of the level of aggregation used in the classification system.Patient costs, Clinical Risk Groups, Variation explained, Overhead allocation
Monitoring the upper southeastern Atlantic transports using altimeter data
A large in-situ data set, collected in the southeastern Atlantic Ocean, is merged with the TOPEX/POSEIDON altimeter observations in order to verify the use of altimeter data in monitoring the transports of the Agulhas/Benguela system. Comparisons between altimeter observations and either moored current meters or inverted echo sounder measurements shows that the sea-surface elevation anomaly is significantly correlated with the thermocline depth and the surface dynamic height, respectively. Knowing the least-squares regression parameters, it is possible to calculate the transports by using geostrophy and either a two-layer or a continuously-stratified model. The transports obtained from fits of dynamic height to altimeter sea-surface height are similar to the ones calculated with the moored instruments. In the southern part of the area under analysis, around 35S, close to the Agulhas retroflection, the transports obtained from the two-layer model are overestimated. Across the Benguela Current, at 30S, transports are still overestimated but of the same order as the measured ones. In this part of the region, the two-layer model can be successfully used to calculate the total and barotropic transports of the Benguela Current. Analysis of the three years of geostrophic transport obtained from the altimeter data indicate that the mean Benguela Current transport does not change interannually more than 20%. However, the primary interannual variability derives from the source water that forms the Benguela Current
MOLEC: Anywhere and at Any Time Arrhythmia Classification
The new advances in sensor technology, PDAs and wireless communications favor the development of a new type of monitoring systems that can provide patients with assistance anywhere and at any time. Of particular interest are the monitoring systems designed for people that suffer from heart arrhythmias, due to the increasing number of people with cardiovascular diseases. In this paper, we present MOLEC: a PDA-based system that performs local real-time classification and detects the ECG anomalies in situ. In the actual implementation of MOLEC, the signal is acquired by some ECG sensors (ActiveECG sensors) with a 360Hz frequency. For the preprocessing of the signal the ECGPUWAVE tool and an automata developed by us that identifies the beats are used. We have also developed a beat and rhythm classifiers that determine if there has been an anomalous rhythm, and in that case, an alarm is sent to a hospital via wireless communications. The rhythm detection delay of the MOLEC system is of 6.66 seconds. classifier that can run in real-time into a PDA. In this paper we show first the framework of the system, then in section 3 the process that we followed in order to select a beat and rhythm classifier that provides an accuracy result and in section 4 we show some performance aspects considering PDAs resources. 2. Framework of the MOLEC system In this section we explain the four components that form the global architecture of MOLEC (see figure 1): the ECG sensor, the Monitor Molec, Molec Center and the users of the system (hospital and relative computers). 1
The Structural and Functional Connectome and Prediction of Risk for Cognitive Impairment in Older Adults
The human connectome refers to a comprehensive description of the brain's structural and functional connections in terms of brain networks. As the field of brain connectomics has developed, data acquisition, subsequent processing and modeling, and ultimately the representation of the connectome have become better defined and integrated with network science approaches. In this way, the human connectome has provided a way to elucidate key features of not only the healthy brain but also diseased brains. The field has quickly evolved, offering insights into network disruptions that are characteristic for specific neurodegenerative disorders. In this paper, we provide a brief review of the field of brain connectomics, as well as a more in-depth survey of recent studies that have provided new insights into brain network pathologies, including those found in Alzheimer's disease (AD), patients with mild cognitive impairment (MCI), and finally in people classified as being "at risk". Until the emergence of brain connectomics, most previous studies had assessed neurodegenerative diseases mainly by focusing on specific and dispersed locales in the brain. Connectomics-based approaches allow us to model the brain as a network, which allows for inferences about how dynamic changes in brain function would be affected in relation to structural changes. In fact, looking at diseases using network theory gives rise to new hypotheses on mechanisms of pathophysiology and clinical symptoms. Finally, we discuss the future of this field and how understanding both the functional and structural connectome can aid in gaining sharper insight into changes in biological brain networks associated with cognitive impairment and dementia
Far-infrared absorption in parallel quantum wires with weak tunneling
We study collective and single-particle intersubband excitations in a system
of quantum wires coupled via weak tunneling. For an isolated wire with
parabolic confinement, the Kohn's theorem guarantees that the absorption
spectrum represents a single sharp peak centered at the frequency given by the
bare confining potential. We show that the effect of weak tunneling between two
parabolic quantum wires is twofold: (i) additional peaks corresponding to
single-particle excitations appear in the absorption spectrum, and (ii) the
main absorption peak acquires a depolarization shift. We also show that the
interplay between tunneling and weak perpendicular magnetic field drastically
enhances the dispersion of single-particle excitations. The latter leads to a
strong damping of the intersubband plasmon for magnetic fields exceeding a
critical value.Comment: 18 pages + 6 postcript figure
Lifetime suicidal-related behaviour among patients in treatment forsubstance use disorder: a cross-sectional study
Suicidal-related behaviours are an important concern in individuals who present with substance use disorders
(SUDs). The distinction among the specific characteristics of the different patients might help to improve prevention strategies. We describe and compare the sociodemographic characteristics, severity of addiction, and
psychopathology of the participants depending on the severity of their lifetime suicidal behaviour. In addition,
we examine whether the number of suicide attempts can be estimated based on the variables that differentiate
the groups. A sample of 318 men and 86 women who sought treatment for addiction were assessed. The sample
was divided into: no ideation or attempts, suicidal ideation, one suicide attempt, and two or more suicide attempts. The group with two or more suicide attempts exhibited a greater severity in the addiction profile. The
group with one suicide attempt presented a higher psychopathological symptomatology at the time of the
assessment. The severity of the Psychiatric area was related to the group with two or more attempts and to the
number of suicide attempts. The presence of any number of attempts is associated with greater severity of
addiction. Providing specific intervention strategies for SUD patients depending on their suicidal behaviours is
promising for clinical application.The first author was supported by a grant from the European UnionNext Generation EU by Ministerio de Universidades (Gobierno de
España) and Universidad del PaÃs Vasco (UPV/EHU).
The second author was supported by a grant (589/2021) from Universidad Pública de Navarra and Fundación Bancaria Caja Navarra.
Open access funding provided by Universidad Pública de Navarr
Reactividad del cemento aluminóso en agua: Caracterización de la fase acuosa de los poros y de la fase sólida
The hydration reaction of high alumina cement at a temperature of 20 ºC and water/cement ratio of 0.5 has been studied over a period of one month. The changes of the solid phase were followed by X-ray diffraction and thermal analysis. Besides, pore-solution was expressed by application of high mechanical pressure (500 MPa) during different periods of the reaction in order to study its Chemical composition evolution as a result of the hydration process.La reacción de hidratación del cemento aluminoso (CA), a la temperatura de 20 ºC y relación agua/cemento de 0,5, ha sido estudiada durante un mes. Los cambios de la fase sólida se siguieron por difracción de rayos X y análisis térmico. Además, la fase acuosa de los poros (FAP) fue extraÃda mediante aplicación de altas presiones mecánicas (500 MPa) en diferentes etapas de la reacción, con el fin de estudiar la evolución de su composición quÃmica durante el proceso de hidratación
Enhanced suppresion of localization in a continuous Random-Dimer Model
We consider a one-dimensional continuous (Kronig-Penney) extension of the
(tight-binding) Random Dimer model of Dunlap et al. [Phys. Rev. Lett. 65, 88
(1990)]. We predict that the continuous model has infinitely many resonances
(zeroes of the reflection coefficient) giving rise to extended states instead
of the one resonance arising in the discrete version. We present exact,
transfer-matrix numerical calculations supporting, both realizationwise and on
the average, the conclusion that the model has a very large number of extended
states.Comment: 10 pages, 3 Figures available on request, REVTeX 3.0, MA/UC3M/1/9
Practical recommendations for measuring rates of visual field change in glaucoma
To date, there has been a lack of evidence-based guidance on the frequency of visual field examinations required to identify clinically meaningful rates of change in glaucoma. The objective of this perspective is to provide practical recommendations for this purpose. The primary emphasis is on the period of time and number of examinations required to measure various rates of change in mean deviation (MD) with adequate statistical power. Empirical data were used to obtain variability estimates of MD while statistical modelling techniques derived the required time periods to detect change with various degrees of visual field variability. We provide the frequency of examinations per year required to detect different amounts of change in 2, 3 and 5 years. For instance, three examinations per year are required to identify an overall change in MD of 4 dB over 2 years in a patient with average visual field variability. Recommendations on other issues such as examination type, strategy and quality are also made
Quantitative study of hydration of C3S and C2S by thermal analysis. Evolution and composition of C-S-H gels formed
This research is part of a European project (namely, CODICE project), main objective of which is modelling, at a multi-scale, the evolution of the mechanical performance of non-degraded and degraded cementitious matrices. For that, a series of experiments were planned with pure synthetic tri-calcium silicate (C3S) and bi-calcium silicate (C2S) (main components of the Portland cement clinker) to obtain different calcium–silicate–hydrate (C–S–H) gel structures during their hydration. The characterization of those C–S–H gels and matrices will provide experimental parameters for the validation of the multi-scale modelling scheme proposed. In this article, a quantitative method, based on thermal analyses, has been used for the determination of the chemical composition of the C–S–H gel together with the degree of hydration and quantitative evolution of all the components of the pastes. Besides, the microstructure and type of silicate tetrahedron and mean chain length (MCL) were studied by scanning electron microscopy (SEM) and 29Si magic-angle-spinning (MAS) NMR, respectively. The main results showed that the chemical compositions for the C–S–H gels have a CaO/SiO2 M ratio almost constant of 1.7 for both C3S and C2S compounds. Small differences were found in the gel water content: the H2O/SiO2 M ratio ranged from 2.9 ± 0.2 to 2.6 ± 0.2 for the C3S (decrease) and from 2.4 ± 0.2 to 3.2 ± 0.2 for the C2S (increase). The MCL values of the C–S–H gels, determined from 29Si MAS NMR, were 3.5 and 4 silicate tetrahedron, for the hydrated C3S and C2S, respectively, remaining almost constant at all hydration periods
- …