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We consider de Finetti’s problem for spectrally one-sided Lévy risk models with control strategies that are absolutely continuous with respect to the Lebesgue measure. Furthermore, we consider the version with a constraint on the time of ruin. To characterize the solution to the aforementioned models, we first solve the optimal dividend problem with a terminal value at ruin and show the optimality of threshold strategies. Next, we introduce the dual Lagrangian problem and show that the complementary slackness conditions are satisfied, characterizing the optimal Lagrange multiplier. Finally, we illustrate our findings with a series of numerical examples.
Hypertension (HTN) remains a common complication after kidney transplantation among paediatric patients. Although low birth weight (LBW) has been implicated as an important risk factor for cardiovascular diseases, its effect on transplantation patients has not yet been addressed. It is essential to determine whether children with LBW who undergo transplantation are more likely to develop post-transplantation HTN. For this study, the medical records of 96 kidney recipients were retrospectively examined. A total of 83 patients fulfilled the inclusion criteria. Overall, post-transplantation HTN was observed in 54% of the recipients. Multivariate logistic regression revealed that time from transplantation >14 months (odds ratio (OR) 3.6; 95% confidence interval (CI) 1.31–10.06; P = 0.013), current CKD (OR 2.6; 95% CI 1.01–7.20; P = 0.045), presence of LBW (OR 3.6; 95% CI 1.04–12.32; P = 0.044) and current overweight/obesity (OR 3.7; 95% CI 1.02–13.91; P = 0.047) were associated with post-transplantation HTN. In conclusion, our data provide evidence for the first time that LBW is a significant predictive factor in the development of post-transplantation HTN. This finding has important clinical implications as it serves to alert clinicians about this additional risk factor in paediatric patients undergoing kidney transplant.
Background: The importance of economic evaluation in decision making is growing with increasing budgetary pressures on health systems. Diverse economic evidence is available for a range of interventions across national contexts within Europe, but little attention has been given to identifying evidence gaps that, if filled, could contribute to more efficient allocation of resources. One objective of the Research Agenda for Health Economic Evaluation project is to determine the most important methodological evidence gaps for the ten highest burden conditions in the European Union (EU), and to suggest ways of filling these gaps.
Methods: The highest burden conditions in the EU by Disability Adjusted Life Years were determined using the Global Burden of Disease study. Clinical interventions were identified for each condition based on published guidelines, and economic evaluations indexed in MEDLINE were mapped to each intervention. A panel of public health and health economics experts discussed the evidence during a workshop and identified evidence gaps.
Results: The literature analysis contributed to identifying cross-cutting methodological and technical issues, which were considered by the expert panel to derive methodological research priorities.
Conclusions: The panel suggests a research agenda for health economics which incorporates the use of real-world evidence in the assessment of new and existing interventions; increased understanding of cost-effectiveness according to patient characteristics beyond the “-omics” approach to inform both investment and disinvestment decisions; methods for assessment of complex interventions; improved cross-talk between economic evaluations from health and other sectors; early health technology assessment; and standardized, transferable approaches to economic modeling.
A series of simple analytical models for the evolution a galactic disk have been constructed. General solutions can be obtained under the assumption of pure radial gas flows, a star formation rate proportional to the nth power of the surface gas density, a constant IMF, and the instantaneous recycling approximation. Models with small radial flow velocities in the range 0.05 to 0.1 km s–1 and an initial exponential surface mass density can reproduce, for galactocentric radii larger than about 5 kpc, the Galactic 16O abundance gradient and the present surface gas distribution.
The aim of this study was to evaluate the performance of cavy (Galea spixii) epididymal sperm following addition to TES or TRIS extenders and using a thermal resistance test (TRT), as well as fluorescence analysis as a complementary method to predict the viability of these gametes. Nine testicle–epididymis complexes were used for sperm collection using a flotation method. Epididymis tails were sliced and one was immersed in 3 ml of TRIS buffer, and the other in 3 ml of TES, for 5 min. After sperm recovery, the samples were subjected to a TRT which involved incubation in a water bath at 37°C for 3 h. During incubation, sample parameters were assessed at 0, 15, 30, 60, 90, 120, 150 or 180 min intervals. Results indicated that the TRIS diluent was more efficient than TES (P < 0.05) for the maintenance of sperm parameters in Spix's yellow-toothed cavies over the whole TRT, maintaining sperm longevity for an extended time. In conclusion, we indicate the use of TRIS diluent for recovery and maintenance of longevity of epididymal sperm from cavies (G. spixii).
Microtremor measurements and the horizontal-to-vertical spectral ratio (HVSR)
technique, generally used for site effect studies as well as to determine the
thickness of soft sedimentary layers, can effectively be applied to map the
thickness of glaciers. In this work the radio-echo sounding, geoelectric and
active seismic methods, widely employed to image the earth interior, are applied
to verify the reliability of the HVSR technique in Alpine and Antarctic glacial
environments. The technique has been used to analyze passive seismic data from
glaciers of the Adamello and Ortles-Cevedale massifs (Italy), the Bernese
Oberland Alps (Switzerland) and from the Whillans Ice Stream (West Antarctica).
Comparing with the results obtained from the different geophysical imaging
methods, we show that the resonance frequency in the HVSR spectra correlates
well with the ice thickness at the site, in a wide range from a few tens of
meters to more than 800 m. The reliability of the method mainly depends
on the coupling of sensors at the glacier surface and on the basal impedance
contrast. This passive seismic technique offers a logistically efficient and
cost effective method to map glacier and ice-sheet thicknesses. Moreover, under
certain conditions, it allows reliable estimations of the basal seismic
Pervasive systems are intended to make use of services and components that they encounter in their environment. Such systems are naturally spatial in that they can only be understood in terms of the ways in which components meet and interact in space. Rather than treating spatiality separately from system components, researchers are starting to develop computational models in which the entire structure of a pervasive system is modelled and constructed using an explicit spatial model, supporting multi-level spatial reasoning, and adapting autonomously to spatial interactions. In this paper, we review current and emerging models of spatial computing for pervasive ecosystems, and highlight some of the trends that will guide future research.
The formation of ring nebulae and their shapes is studied by numerical simulations. The old problem of the origin of the nebular shape is addressed. Two proposed mechanisms are discussed: stellar rotation and stellar magnetic fields, or a combination of both. Two and three-dimensional hydrodynamical and magneto-hydrodynamical simulations indicate that these processes are equally efficient in driving elliptical nebulae such as those surrounding Wolf-Rayet stars, like NGC 6888 around WR136. However, bipolar nebulae are better reproduced by rotation.
We present hydrodynamical and magnetohydronynamical simulations for the formation and evolution of bipolar and elliptical planetary nebulae with two interacting winds. The models are performed under the hypothesis of a single central source, i.e. binary systems are not considered and a single initial wind function is used in our calculations. We explore various relevant parameters, including the effects of stellar rotation, ionizing radiation field and stellar magnetic field, and a catalogue of resulting shapes is generated.
The main features of HII regions expanding in spherical and disk-like clouds with density gradients are reviewed. The spherical cases assume power-law density stratifications, r~w, and the disk-like cases include exponential, gaussian, and sech2 distributions. For power-law profiles, there is a critical exponent, wcrit = 3/2, above which the ionization front cannot be “trapped” and the cloud becomes fully ionized. For clouds with w < 3/2, the radius of the ionized region grows as t4/(7-2w) and drives a shock front into the ambient neutral medium. For w = wcrit = 3/2 the shock wave cannot detach from the ionization front and the two move together with a constant speed equal to about 2ci, where ci is the sound speed in the ionized gas. For w > 3/2 the expansion corresponds to the “champagne phase”, and two regimes, fast and slow, are apparent: between 3/2 < w ≤ 3, the slow regime, the inner region drives a weak shock moving with almost constant velocity through the cloud, and for w > 3, the fast regime, the shock becomes strong and accelerates with time.
For the case of disk-like clouds, which are assumed cylindrically symmetric, the dimensions of the initial HII regions along each azimuthal angle, θ, are described in terms of the Strömgren radius for the midplane density, Ro, and the disk scale height, H. For yo = Rosin(θ)/H ≤ α (where α is a constant dependent on the assumed density distribution) the whole HII region is contained within the disk, and for yo > α a conical section of the disk becomes totally ionized. The critical azimuthal angle above which the HII region becomes unbounded is defined by θcrit =sin-1(αH/Ro). The expansion of initially unbounded HII regions (i.e. with yo > α) proceeds along the z-axis and, if the disk column density remains constant during the evolution, the ionization front eventually recedes from infinity to become trapped within the expanding disk. For clouds threaded by a B-field oriented parallel to the symmetry axis, as expected in magnetically dominated clouds, this effect can be very prominent. The expanding gas overtaken by the receding ionization front maintains its linear momentum after recombination and is transformed into a high-velocity neutral outflow. In the absence of magnetic fields, the trapping has only a short duration.
The preparation for The International Year of Astronomy 2009 stirred our interest in preparing star parties in Mexico. The lunar eclipse of February 20th 2008 was the perfect event for the first massive observation in Mexico City that attracted over 25,000 people. To accompany this event there were additional attractions: a massive astronomical lecture, more than 100 telescopes were set up for people to watch the sky, exhibits of astronomical images, children hands-on projects, rock concert, dance performance, and chats with astronomers. Already in 2009 a collective program was organized to involve more than 30 sites in Mexico to hold star parties at the same time once a year. These star parties were more in the spirit of science fairs, that include lectures, astronomy exhibits, children projects, as well as concerts and other cultural displays. The scope of each one of them depended on the local support from volunteers and from the local authorities. After the International Year of Astronomy the group that organized these star parties decided to continue its activities. The main attraction in these fairs has been the opportunity to see the Moon, Jupiter and Saturn (if observable) through a telescope. For this program the presence of the amateur astronomers has been crucial. They have brought their instruments to the sites and have generously taught the public how to look through the telescopes and pointed out to the interesting features on the sky.
The degree of development and operability of the indicators for the Marine Strategy Framework Directive (MSFD) using Descriptor 1 (D1) Biological Diversity was assessed. To this end, an overview of the relevance and degree of operability of the underlying parameters across 20 European countries was compiled by analysing national directives, legislation, regulations, and publicly available reports. Marked differences were found between countries in the degree of ecological relevance as well as in the degree of implementation and operability of the parameters chosen to indicate biological diversity. The best scoring EU countries were France, Germany, Greece and Spain, while the worst scoring countries were Italy and Slovenia. No country achieved maximum scores for the implementation of MSFD D1. The non-EU countries Norway and Turkey score as highly as the top-scoring EU countries. On the positive side, the chosen parameters for D1 indicators were generally identified as being an ecologically relevant reflection of Biological Diversity. On the negative side however, less than half of the chosen parameters are currently operational. It appears that at a pan-European level, no consistent and harmonized approach currently exists for the description and assessment of marine biological diversity. The implementation of the MSFD Descriptor 1 for Europe as a whole can therefore at best be marked as moderately successful.
To design and develop a questionnaire that can account for an individual’s adherence to a Mediterranean lifestyle including the assessment of diet and physical activity patterns, as well as social interaction.
The Mediterranean Lifestyle (MEDLIFE) index was created based on the current Spanish Mediterranean food guide pyramid. MEDLIFE is a twenty-eight-item derived index consisting of questions about food consumption (fifteen items), traditional Mediterranean dietary habits (seven items) and physical activity, rest and social interaction habits (six items). Linear regression models and Spearman rank correlation were fitted to assess content validity and internal consistency.
A subset of participants in the Aragon Workers’ Health Study cohort (Zaragoza, Spain) provided the data for development of MEDLIFE.
Participants (n 988) of the Aragon Workers’ Health Study cohort in Spain.
Mean MEDLIFE score was 11·3 (sd 2·6; range: 0–28), and the quintile distribution of MEDLIFE score showed a significant association with each of the individual items as well as with specific nutrients and lifestyle indicators (intra-validity). We also quantified MEDLIFE correspondence with previously reported diet quality indices and found significant correlations (ρ range: 0·44–0·53; P<0·001) for the Alternate Healthy Eating Index, the Alternate Mediterranean Diet Index and Mediterranean Diet Adherence Screener.
MEDLIFE is the first index to include an overall assessment of lifestyle habits. It is expected to be a more holistic tool to measure adherence to the Mediterranean lifestyle in epidemiological studies.
Intestinal mucositis is an important toxic side effect of 5-fluorouracil (5-FU) treatment. Saccharomyces boulardii is known to protect from intestinal injury via an effect on the gastrointestinal microbiota. The objective of the present study was to evaluate the effect of S. boulardii on intestinal mucositis induced by 5-FU in a murine model. Mice were divided into saline, saline (control)+5-FU or 5-FU+S. boulardii (16 × 109 colony-forming units/kg) treatment groups, and the jejunum and ileum were removed after killing of mice for the evaluation of histopathology, myeloperoxidase (MPO) activity, and non-protein sulfhydryl group (mainly reduced glutathione; GSH), nitrite and cytokine concentrations. To determine gastric emptying, phenol red was administered orally, mice were killed 20 min after administration, and the absorbance of samples collected from the mice was measured by spectrophotometry. Intestinal permeability was measured by the urinary excretion rate of lactulose and mannitol following oral administration. S. boulardii significantly reversed the histopathological changes in intestinal mucositis induced by 5-FU and reduced the inflammatory parameters: neutrophil infiltration (control 1·73 (sem 0·37) ultrastructural MPO (UMPO)/mg, 5-FU 7·37 (sem 1·77) UMPO/mg and 5-FU+S. boulardii 4·15 (sem 0·73) UMPO/mg); nitrite concentration (control 37·00 (sem 2·39) μm, 5-FU 59·04 (sem 11·41) μm and 5-FU+S. boulardii 37·90 (sem 5·78) μm); GSH concentration (control 477·60 (sem 25·25) μg/mg, 5-FU 270·90 (sem 38·50) μg/mg and 5-FU+S. boulardii 514·00 (sem 38·64) μg/mg). Treatment with S. Boulardii significantly reduced the concentrations of TNF-α and IL-1β by 48·92 and 32·21 % in the jejunum and 38·92 and 61·79 % in the ileum. In addition, S. boulardii decreased the concentrations of chemokine (C–X–C motif) ligand 1 by 5-fold in the jejunum and 3-fold in the ileum. Interestingly, S. boulardii reduced the delay in gastric emptying (control 25·21 (sem 2·55) %, 5-FU 54·91 (sem 3·43) % and 5-FU+S. boulardii 31·38 (sem 2·80) %) and induced the recovery of intestinal permeability (lactulose:mannitol ratio: control 0·52 (sem 0·03), 5-FU 1·38 (sem 0·24) and 5-FU+S. boulardii 0·62 (sem 0·03)). In conclusion, S. boulardii reduces the inflammation and dysfunction of the gastrointestinal tract in intestinal mucositis induced by 5-FU.
Seven out of ten Black Stork chicks fitted with satellite tags successfully made the journey from Iberia to the Sahel. Four died there during their first winter and one additional bird in the second winter. Our results show that 30% of the tagged fledglings died in Iberia and 50% (5/10) in the Sahel. In the Sahel, Black Storks occupy areas of seasonal rivers and small bodies of water in these sub-Saharan savannas, where they track suitable sites according to the progressive drying of the Sahel after the summer monsoon. This behaviour may make them more susceptible to coming into contact with humans and, consequently, current and future action plans for conserving the Iberian Black Stork population should link efforts with AEWA's Strategic Plan and other international initiatives to promote the global use of water resources for humans and wildlife in the Sahel.
This work shows current research on lithic raw material used by the ancient Maya of Toniná. The core of the city of Toniná lies on a steep-sided hill of calcareous sandstones from the shallow marine deposits dated as Oligocene, in the Chiapas Highlands of Southern Mexico. Results of paleontological fieldwork in Toniná show several biostrome sediments mound-like with tabular bafflestones and large coquina flagstones, which are sheet-like rocks enriched with fossil mollusk shells, corals, encrusted organisms, and calcareous debris. The people of Toniná intentionally selected and carved these rocks for use as building blocks and bricks on floors, walls, and stairways. At least two coquina flagstones measuring about 1.90 m long were identified in an archeological context most likely associated with carved stelae. Also non-marine carbonate rocks such as a crudely banded travertine and spongy calcareous tufa from recent sediments of freshwater environments surrounding Toniná were used by the Maya as a raw material on walls, columns, reliefs and murals base.
Results of the chemical, mineralogical and micromorphological analysis on plaster and bedding mortars from the walls of Toniná display a slightly interbedded lime of sparry calcite cemented in a highly porous groundmass with silt-to pebble-size of calcareous and siliciclastic rock-crushed aggregates, sand, and soil remains. Lime fabric reveals enclosing quartz grains, granular calcite crystals, and carbonaceous inclusions which may suggest that the lime has been made from a burnt grain-rich limestone with fibrous cement and porous microfabric. WDX analysis in lime lumps of plaster reveal an average amount of 1.37 wt% MgO associated with a limestone source ranging from regular to a magnesium-enriched limestone (1 to 2 wt %). XRF detect a strontium-rich level in the calcite matrix of plaster which is as high as that of fossil shells, tufa, and coquina. Finally, XRD shows that the mean amount of calcite in plaster is 95 wt% and lower amount (2-2.5w%) of siliciclastic minerals: quartz and albite. In contrast, calcite in mortar ranges less than 90.1 wt%. The concentrations of non-carbonate minerals, such as quartz and albite, are higher than those in plaster because mortar incorporates more siliciclastic rock remains, sand and clay.
Low germination and seedling survival probabilities are reported in various species of epiphytic bromeliad (Benzing 1978, Hietz et al. 2011, Toledo-Aceves & Wolf 2008, Winkler et al. 2005; but see Cascante-Marín et al. 2008). If germination and seedling survival are limiting factors in the life cycle, differential germination and seedling survival between species should be reflected in the relative abundance of established plants (Cascante-Marín et al. 2006, 2008) and in their presence or absence in secondary vegetation (Hietz et al. 2011), while differential germination within the tree would be expected to contribute to a heterogeneous distribution of established plants within the canopy (Hietz et al. 2011, Zotz & Vollrath 2002). Many factors influence the performance and distribution of epiphytes, including forest condition, disturbance type, distance from seed source, tree size and species, microclimate, epiphyte population dynamics and physiology (Cascante-Marín et al. 2009, Hietz et al. 2011, Valencia-Diaz et al. 2010, Zotz & Hietz 2001). In this study, we tested whether germination and seedling survival rates differ between the epiphytic bromeliads Tillandsia multicaulis Steud., T. punctulata Schldl. & Cham. and T. butzii Mez, and whether species abundance reflects the ability to germinate and survive as seedlings within the cloud-forest canopy. We also explore how morphological and physiological traits of the studied species can influence their early establishment.
Renewed in-depth multi-disciplinary investigation of a large coastal mound settlement in Peru has extended the occupation back more than 7000 years to a first human exploitation ~13720 BP. Research by the authors has chronicled the prehistoric sequence from the activities of the first maritime foragers to the construction of the black mound and the introduction of horticulture and monumentality. The community of Huaca Prieta emerges as innovative, complex and ritualised, as yet with no antecedents.
In this work the change in the structural properties of cassava (manihot sculenta Crantz) thermoplastic starch (TPS) under controlled environment (humidity and temperature) was studied. Fourier Transform Infrared spectroscopy (FTIR) and X-ray diffraction (XRD) results showed an evident increasing in the amorphous phase of the TPS regarding the native starch. There was a relative decrease of the band at 1047 cm-1 associated to crystalline structure of starch compared to the amorphous peak at 1022 cm-1. The X-ray diffraction patterns confirmed the increment of the amorphous phase in the TPS samples. Likewise the X-ray diffraction patterns shows evidence of residual type C crystallinity and the formation of a new crystalline phase type VH due to the orientation induced in plasticization process. In first stage of conditioning the tensile yield stress drops from 7.5 drops to 0.5 MPa and the break strain increases 1000%. At the same time it seems that the crystallinity of the samples increases as was evidenced by the gradually increasing of the FTIR band at 1047 cm-1. In a second stage, the yield stress increases, the break strain drops and the crystallinity continue growing steadily. These findings suggest that coexist two phenomena simultaneously in the samples. A phenomenon of re-crystallization (retrogradation) that tends to make the material more stiff and a process of plasticization that tends to softening it. It seems that the latter mechanism predominates in the first stage, at short times, and the former in the second stage, at older times.