PREMIUM CALCULATIONS FOR COMPARTMENTAL MODEL USING DISCRETE ANALOGUES OF CONTINUOUS LOSS DISTRIBUTIONS

In the present paper we consider some discrete analogues of continuous loss distributions to illustrate their actuarial applications using a simple deterministic epidemiological model. We give numerical illustrations using different parameter values of discrete analogues of continuous loss distributions. We also give level premiums for annuity assuming future premium to be paid by the susceptible individual or future claim to be made by the infected individual follow some discrete analogues of continuous loss distributions.

A STUDY ON ENDOTHELIAL CELL LOSS AFTER OPTICAL KERATOPLASTY- A RETROSPECTIVE STUDY IN A TERTIARY EYE CARE CENTRE IN CHENNA

Aim: a study of endothelial cell loss after optical keratoplasty in 50 patients in a tertiary care centre in Chennai. Materials and Methods: A retrospective study was carried out on 50 patients who underwent optical keratoplasty in a tertiary care centre in Chennai. 50 patients in the age group 11-80 were included in this study. Postoperatively they were periodically followed up regarding graft clarity, presence of vascularisation, vision and endothelial cell count. During follow up presence of any complications were assessed and recorded. At the end of 6 months, there was an average of 37.5% loss of endothelial ce Observation And Results: lls in PKP and 44.5% in LKPs and 38.6% in Triple procedure. At the end of one month, patients who had repeat Keratoplasty for failed graft had more loss (20.1%) whereas at the end of 6 months, Pseudophakic Bullous Keratopathy patients showed more loss (49.4%). These indicate migration of endothelial cells along a density gradient after keratoplasty. Overall there is continuous loss of endothel Conclusion: ial cells in all cases of Keratoplasty regardless of the indication for keratoplasty and the type of keratoplasty. Even in cases of clear grafts, there is a continuous loss of endothelial cells. It has been reported that chronic subclinical rejection, chronic low-level inammation or continued interaction between the donor endothelium and a healthy recipient endothelium could explain the greater cell loss

Five endemic Peperomia (Piperaceae) novelties from Veracruz, Mexico

Five new species of Peperomia (Piperaceae), endemic to the state of Veracruz, Mexico, are described, illustrated, compared with morphologically close taxa and assigned to their respective subgenus. Peperomia castilloi Vergara-Rodríguez & Jimeno-Sevilla, P. nopalana G.Mathieu, P. trichobracteata G.Mathieu & T.Krömer and P. xalana G.Mathieu are four somewhat similar species that occur at lower elevations in tropical humid forests. Peperomia zongolicana Jimeno-Sevilla & Vergara-Rodríguez occurs in tropical humid forests at mid-range elevations and is very distinct by the shape of its inflorescences. An assessment of their conservation status, considering IUCN Red List categories and criteria, revealed that they all belong to a threatened category, mainly due to the continuous loss and fragmentation of their natural habitats.

A parameterization of respiration in frozen soils based on substrate availability

Respiration in frozen soils is limited to thawed substrate within the thin water films surrounding soil particles. As temperatures decrease and the films become thinner, the available substrate also decreases, with respiration effectively ceasing at −8 °C. Traditional exponential scaling factors to model this effect do not account for substrate availability and do not work at the century to millennial timescales required to model the fate of the nearly 1100 Gt of carbon in permafrost regions. The exponential scaling factor produces a false, continuous loss of simulated permafrost carbon in the 20th century and biases in estimates of potential emissions as permafrost thaws in the future. Here we describe a new frozen biogeochemistry parameterization that separates the simulated carbon into frozen and thawed pools to represent the effects of substrate availability. We parameterized the liquid water fraction as a function of temperature based on observations and use this to transfer carbon between frozen pools and thawed carbon in the thin water films. The simulated volumetric water content (VWC) as a function of temperature is consistent with observed values and the simulated respiration fluxes as a function of temperature are consistent with results from incubation experiments. The amount of organic matter was the single largest influence on simulated VWC and respiration fluxes. Future versions of the parameterization should account for additional, non-linear effects of substrate diffusion in thin water films on simulated respiration. Controlling respiration in frozen soils based on substrate availability allows us to maintain a realistic permafrost carbon pool by eliminating the continuous loss caused by the original exponential scaling factors. The frozen biogeochemistry parameterization is a useful way to represent the effects of substrate availability on soil respiration in model applications that focus on century to millennial timescales in permafrost regions.

Understanding problems of lithiated anodes in lithium oxygen full-cells

Ambiguously unsolved problems in lithium oxygen full-cells were intensively investigated. The formation of LiOH at the anode side causes continuous loss of the Li+ ions, and thus results in decreased potential and poor cycling of the Li–O2 full-cell.

A parameterization of respiration in frozen soils based on substrate availability

Respiration in frozen soils is limited to thawed substrate within the thin water films surrounding soil particles. As temperatures decrease and the films become thinner, the available substrate also decreases, with respiration effectively ceasing at −8 °C. Traditional exponential scaling factors to model this effect do not account for substrate availability and do not work at the century to millennial time scales required to model the fate of the nearly 1700 Gt of carbon in permafrost regions. The exponential scaling factor produces a false, continuous loss of simulated permafrost carbon in the 20th century and biases in estimates of potential emissions as permafrost thaws in the future. Here we describe a new frozen biogeochemistry parameterization that separates the simulated carbon into frozen and thawed pools to represent the effects of substrate availability. We parameterized the liquid water fraction as a function of temperature based on observations and use this to transfer carbon between frozen pools and thawed carbon in the thin water films. The simulated volumetric water content (VWC) as a function of temperature is consistent with observed values and the simulated respiration fluxes as a function of temperature are consistent with results from incubation experiments. The amount of organic matter was the single largest influence on simulated VWC and respiration fluxes. Future versions of the parameterization should account for additional, non-linear effects of substrate diffusion in thin water films on simulated respiration. Controlling respiration in frozen soils based on substrate availability allows us to maintain a realistic permafrost carbon pool by eliminating the continuous loss caused by the original exponential scaling factors. The frozen biogeochemistry parameterization is a useful way to represent the effects of substrate availability on soil respiration in model applications that focus on century to millennial time scales in permafrost regions.

ON THE RECOVERABILITY OF FORECASTERS’ PREFERENCES

We study the problem of identifying a forecaster’s loss function from observations on forecasts, realizations, and the forecaster’s information set. Essentially different loss functions can lead to the same forecasts in all situations, though within the class of all continuous loss functions, this is strongly nongeneric. With the small set of exceptional cases ruled out, generic nonparametric preference recovery is theoretically possible, but identification depends critically on the amount of variation in the conditional distributions of the process being forecast. There exist processes with sufficient variability to guarantee identification, and much of this variation is also necessary for a process to have universal identifying power. We also briefly address the case in which the econometrician does not fully observe the conditional distributions used by the forecaster, and in this context we provide a practically useful set identification result for loss functions used in forecasting binary variables.

Research on the Microbiological Diversity of the Chernozem Soil of Dobroudja, in the VALU TRAIAN Region

The most poignant global crisis is the one triggered by the conflict between the environment, the agriculture and the society. The continuous loss of humus and of the biodiversity combined with the decrease of the soil’s fertility, with losing its capacity to produce nourishment, energy and raw stocks lead to the impoverishment of the population. Dobroudja is the most barren region, the draught being an endemic phenomenon, desertification also being present, currently in the soil there is a maximum 2,65 t/ha of active biological substance and 109 t/ha of humus, which represents a 56% decrease compared to 80 years ago. We have set off to create an adequate plan to ecologically and biologically reconstruct the soil based on the research done in the Valu Traian area of Dobroudja. Firstly, we have stock-listed the current biological state of the soil in the Dobroudja ecosystem and then, by using laystall and Biovin bioactivators, we will try to feed into the soil as much micro-organisms and specific organisms as possible that are necessary to restore and biocatalytically reconstruct the organic substance into heteropolycondensated humus.