Optimal reinsurance of dependent risks

We analyse the problem of nding the optimal combination of quota-share and stop loss treaties, maximizing the expected utility or the adjustment coecient of the ce- dent, for each of two risks dependent through a copula structure. By risk we mean a line of business or a portfolio of policies. Results are obtained numerically, using the software Mathematica. Sensitivity of the optimal reinsurance strategy to several factors are investigated, including: i) the dependence level, by means of the Kendall's tau and the dependence parameter; ii) the type of dependence, using dierent copulas describing dierent tail behaviour; iii) the reinsurance calculation principles, where expected value, variance and standard deviation principles are considered. Results show that dierent dependence structures, yield signicantly dierent optimal solu- tions. The optimal treaty is also very sensible to the reinsurance premium calculation principle. Namely, for variance related premiums the optimal solution is not the pure stop loss. In general, the maximum adjustment coecient decreases when dependence increases..info:eu-repo/semantics/publishedVersio

Too Many Is Too Bad: Long-Term Net Negative Effects of High Density Ungulate Populations on a Dominant Mediterranean Shrub

Plant–animal interactions imply costs and benefits with net balance depending on interacting species and ecological context. Ungulates, in particular, confer costs (e.g., plant leaf consumption, flower bud predation) and benefits (e.g., plant overcompensation, seed dispersal) to plants. Magnitude of costs and benefits may be altered by habitat management or ecological conditions favoring high density ungulate populations. Little is known however on whether plant costs or benefits predominate over the years, or the long-term outcomes of plant-animal interactions in habitat types sustaining high density ungulate populations. We investigated how high density ungulate populations alter plant costs and benefits by quantifying ungulate long-term effects on the shrub Cistus ladanifer (Cistaceae) individual size, seed weight and number, seed bank, and population density, through a 12-year ungulate exclusion experiment in a Mediterranean scrubland. We monitored plant size and flower buds in plants exposed or protected from ungulates and number of developed capsules and seeds consumed (potential seed dispersal) by ungulates during three reproductive seasons. We found that ungulates negatively affected shrub size and led to a dramatically decline of shrub reproductive structures and seed production, affecting the plant reproductive cycle. Number of buds was 27 times higher and number of developed seed 5 times higher in ungulate-excluded as compared to ungulate-exposed plots. After 9 years of ungulate exclusion, the C. ladanifer seed bank was 2.6 times higher in ungulate-excluded plots. The population density of C. ladanifer was 4 times higher in ungulate-excluded plots. Our long-term experiment showed that high density ungulate populations can alter plant-animal interactions by reducing plant benefits and increasing plant costs.Peer reviewe

COPD control: Can a consensus be found?

AbstractThere are currently no reliable instruments for assessing the onset and progression of chronic obstructive pulmonary disease (COPD) or predicting its prognosis. Currently, a comprehensive assessment of COPD including several objective and subjective parameters is recommended. However, the lack of biomarkers precludes a correct assessment of COPD severity, which consequently hampers adequate therapeutic approaches and COPD control. In the absence of a definition of “well-controlled disease”, a consensus regarding COPD control will be difficult to reach. However, COPD patient assessment should be multidimensional, and anchored in five points: control of symptoms, decline of pulmonary function, levels of physical activity, exacerbations, and Quality of Life.Several non-pharmacological and pharmacological measures are currently available to achieve disease control. Smoking cessation, vaccination, exercise training programs and pulmonary rehabilitation are recognized as important non-pharmacological measures but bronchodilators are the pivotal therapy in the control of COPD. This paper discusses several objective and subjective parameters that may bridge the gap between disease assessment and disease control. The authors conclude that, at present, it is not possible to reach a consensus regarding COPD control, essentially due to the lack of objective instruments to measure it. Some recommendations are set forth, but true COPD control awaits further objective assessments

Sleep apnea and atrial fibrillation - A different kind of rhythm

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Pneumonia organizativa – Experiência da consulta de um hospital central

AbstractAim: to characterise outpatients of a Portuguese central hospital diagnosed with organising pneumonia (OP) and compare results with current literature. Methods: medical processes with diagnosis of OP were retrospectively studied as to demographics, aetiology, clinical and radiological features, average time until and date of diagnosis, laboratory and histological changes, treatment and relapse. Results – thirteen patients with a mean follow-up of 171.6weeks (max 334 and min 28 weeks) were evaluated. Nine of these patients (70%) had cryptogenic OP (COP) while 30% had secondary OP (SOP), two with rheumatoid arthritis, one with dermatomyositis and another undergoing radiotherapy for breast cancer. Mean age was 55.6 (+-15.3years), 92% female, 77% were non-smokers. Average time until diagnosis was 77.2weeks (min 3 and max 432 weeks). Symptoms at presentation were tiredness (92%), cough (85%), fever (65%), shortness of breath (54%), thoracic pain (23%) and weight loss (23%). At the time of diagnosis, the mean erythrocyte sedimentation rate was 70mm (max 170mm and min 16mm). C-reactive protein level was increased in eight patients. Significant leucocytosis was absent. Chest X-ray and chest CT scan showed bilateral distribution in 12 patients (92%). Consolidation with an air bronchogram was present in 12 patients and in four (31%), consolidation was migratory. Four patients (30%) underwent transbronchial pulmonary biopsy, all uncharacteristic and eight patients surgical pulmonary biopsy, four showed histological confirmation of SOP. Corticosteroids were started in 11 patients and average treatment was 61.6weeks (16-288 weeks). 15% (2/13) had spontaneous resolution. Four patients (31%) relapsed, one of them five times. Two patients are dependent on a low dose of corticosteroids, one due to underlying disease and another due to multiple relapses. Therapy of relapse was corticosteroids alone in minimum effective dosage or associated to azathioprine or ciclosporin. Discussion and conclusion: such a high incidence in females (92%) may be explained by the limited sample of patients. In 70% of the patients diagnosis were established by clinical and radiology criteria. Mean time to diagnosis was very variable which suggests that in some cases the disease was not diagnosed and treated as another interstitial lung disease or as recurrent pneumonia. Most patients (53.8%) had a favourable clinical course after treatment with corticosteroids with a very low number of relapses (30.8%), much lower than described by other authors (60%). Only in experienced centres should the diagnosis of OP established by clinical and radiological criteria.Rev Port Pneumol 2010; XVI (3): 369-38

Psychosis Assessment in Early-Stage Parkinson's Disease: Comparing Parkinson's Psychosis Questionnaire with the Brief Psychiatric Rating Scale in a Portuguese Sample

Psychotic symptoms in Parkinson's disease (PD) are frequent, disabling, and an important prognostic factor. Thus, screening instruments for detecting psychosis in PD are needed. For this purpose, we applied the Parkinson's Psychosis Questionnaire (PPQ), a short structured questionnaire, which requires no specific training, along with the Brief Psychiatric Rating Scale, expanded version (BPRS-E), for rating general psychopathology, including psychotic symptoms. We evaluated, in a cross-sectional study, a Portuguese sample of 36 early-stage PD patients (mean age of 73 years; mean duration of illness of 3.2 years). The PPQ total score correlated with the BPRS-E total score (0.359; P = 0.032) and with the BPRS-E-positive symptoms score (0.469; P = 0.004). The prevalence of psychosis (41.7%) was higher than expected. Sampling bias and detection of minor psychotic phenomena may have contributed to this result. These findings suggest that the PPQ should be further evaluated as a feasible assessment for psychotic symptoms in PD

Lung and Intercostal Upper Abdomen Ultrasonography for Staging Patients with Ovarian Cancer: A Method Description and Feasibility Study

A detailed transabdominal and transvaginal ultrasound examination, performed by an expert examiner, could render a similar diagnostic performance to computed tomography for assessing pelvic/abdominal tumor spread disease in women with epithelial ovarian cancer (EOC). This study aimed to describe and assess the feasibility of lung and intercostal upper abdomen ultrasonography as pretreatment imaging of EOC metastases of supradiaphragmatic and subdiaphragmatic areas. A preoperative ultrasound examination of consecutive patients suspected of having EOC was prospectively performed using transvaginal, transabdominal, and intercostal lung and upper abdomen ultrasonography. A surgical-pathological examination was the reference standard to ultrasonography. Among 77 patients with histologically proven EOC, supradiaphragmatic disease was detected in 13 cases: pleural effusions on the right (n = 12) and left (n = 8) sides, nodular lesions on diaphragmatic pleura (n = 9), focal lesion in lung parenchyma (n = 1), and enlarged cardiophrenic lymph nodes (n = 1). Performance (described with area under the curve) of combined transabdominal and intercostal upper abdomen ultrasonography for subdiaphragmatic areas (n = 77) included the right and left diaphragm peritoneum (0.754 and 0.575 respectively), spleen hilum (0.924), hepatic hilum (0.701), and liver and spleen parenchyma (0.993 and 1.0 respectively). It was not possible to evaluate the performance of lung ultrasonography for supradiaphragmatic disease because only some patients had this region surgically explored. Preoperative lung and intercostal upper abdomen ultrasonography performed in patients with EOC can add valuable information for supradiaphragmatic and subdiaphragmatic regions. A reliable reference standard to test method performance is an area of future research. A multidisciplinary approach to ovarian cancer utilizing lung ultrasonography may assist in clinical decision-making.info:eu-repo/semantics/publishedVersio

Low temperature matrix-isolation and solid state vibrational spectra of tetrazole

Infrared spectra of tetrazole (CN isolated in an argon matrix (T \10 K) and in the solid state (at room 4H2) temperature) were investigated. In the crystalline phase, tetrazole exists in its 1H-tautomeric form and new assignments of the vibrational spectra (both infrared and Raman) of this phase are presented. The infrared spectrum of the matrix-isolated monomeric form of tetrazole is now reported and assigned for the Ðrst time, showing essentially the expected signature of the 2H-tetrazole tautomer. From relative intensities of the infrared bands ascribable to the two tautomers, the amount of the 1H-tautomer in the argon matrix was estimated to be ca. 10% of the most stable tautomer. Assuming that gas-phase relative populations of the two tautomers could be efficiently trapped in the argon matrix during deposition, the energy di erence between 1H- and 2H-tetrazole (*E was then obtained. The experimental value, kJ mol~1, 1Hh2H) *E1Hh2H\6.95^1.50 now determined for the Ðrst time, compares fairly well with the theoretical predictions for the molecule in vacuum (e.g., the zero point vibrational energy corrected energy di erence obtained at the B3LYP/6È31G* level of theory is 9.96 kJ mol~1)

Human use of natural capital generates cultural and other ecosystem services in montado and dehesa oak woodlands.

Miguel Bugalho, University of Lisbon, with Teresa Pinto Correia, Centre for Mediterranean Studies, University of Évora, Portugal, and Fernando Pulido, University of Extremadura, Plasencia, Spain, describe the exemple of human use of natural capital generating cultural ecosystem services in the montado and dehesa oak woodlands of the south-western Iberian Peninsula. These two locally adapted management systems have long histories and require advanced practical skills balancing trees, bushes, grass and grazing over space and time. They are outstanding cases of natural and cultural capital in their dynamic, positive and productive interactions with threatened and endemic species that are high conservation value. Several products, derived from livestock management, are key components of local gastronomy and traditional festivities

Agriculture pest and disease risk maps considering MSG satellite data and Land Surface Temperature.

Pest risk maps for agricultural use are usually constructed from data obtained from in-situ meteorological weather stations, which are relatively sparsely distributed and are often quite expensive to install and difficult to maintain. This leads to the creation of maps with relatively low spatial resolution, which are very much dependent on interpolation methodologies. Considering that agricultural applications typically require a more detailed scale analysis than has traditionally been available, remote sensing technology can offer better monitoring at increasing spatial and temporal resolutions, thereby improving pest management results and reducing costs. This article uses ground temperature, or land surface temperature (LST), data distributed by EUMETSAT/LSASAF (with a spatial resolution of 3 x 3 km (nadir resolution) and a revisiting time of 15 min) to generate one of the most commonly used parameters in pest modelling and monitoring: “thermal integral over air temperature (accumulated degree-days)”. The results show a clear association between the accumulated LST values over a threshold and the accumulated values computed from meteorological stations over the same threshold (specific to a particular tomato pest). The results are very promising and enable the production of risk maps for agricultural pests with a degree of spatial and temporal detail that is difficult to achieve using in-situ meteorological stations