Performance Characterization of Random Proximity Sensor Networks

In this paper, we characterize the localization performance and connectivity of sensors networks consisting of binary proximity sensors using a random sensor management strategy. The sensors are deployed uniformly at random over an area, and to limit the energy dissipation, each sensor node switches between an active and idle state according to random mechanisms regulated by a birth-and-death stochastic process. We first develop an upper bound for the minimum transmitting range which guarantees connectivity of the active nodes in the network with a desired probability. Then, we derive an analytical formula for predicting the mean-squared localization error of the active nodes when assuming a centroid localization scheme. Simulations are used to verify the theoretical claims for various localization schemes that operate only over connected active nodes

Challenges of a Statin Trial in Older People

Non peer reviewe

Modeling and Optimization of Single Photon Avalanche Photodiodes for X-Ray Detection

Avalanche Photodiodes (APDs) are electronic devices that transduce a photon flux into an electrical current and provide internal amplification of this current exploiting the impact ionization mechanism. APDs are used as receivers in optical fiber communication links as well as detectors in physics experiments and medical imaging. According to the needs of the target application, they can either be operated below (Linear mode) or above (Geiger mode) their breakdown voltage. For X-ray detection, APDs fabricated in III-V compound semiconductors, such as GaAs, offer an interesting alternative to SiAPDs, thanks to the short attenuation length at high energies offered by these materials. However, to improve the poor noise performance of APDs fabricated in III-V compounds given by similar electron\u2019s and hole\u2019s impact ionization coefficients, structures alternative to p-i-n APDs have to be employed. A possible solution is the use of staircase APDs, where heterojunctions between III-V compound semiconductors and their alloys with metals are exploited to enhance the electron to hole impact ionization probability by creating an artificial superlattice. This thesis aims at proposing models to compute the figures of merit of APDs fabricated in III-V compound semiconductors and operating in Linear mode for the detection of X-rays. Since accurate modeling of impact ionization is key to obtain reliable data from simulations, we present the development of a suite of simulations tools that includes finite difference and a Random Path Length algorithm implementation of a newly derived nonlocal history dependent impact ionization model and a Full Band Monte Carlo transport simulator. All these models have been validated against experimental results and are thus powerful tools in support of the interpretation of single photon APDs electrical measurements and for the optimization of their performance. These simulation tools have been used to compute the gain, the excess noise factor, the response time, the bandwidth and the jitter of different APD structures, including staircase APDs. In addition, the Full Band Monte Carlo transport simulator has been employed to assess the basic assumptions, identify the limitations and improve the calibration of nonlocal history dependent impact ionization models. We have found that, even though nonlocal history dependent models give results that are in a satisfactory agreement with experiments, they neglect that after an impact ionization event secondary carriers are generated with non null kinetic energy and that carrier-phonon scattering may lead to electrons and holes that travel for few free flights with velocities that are opposite to the direction of the electric fields. These aspects may become relevant and yield misleading results, in particular for short devices

TOWARDS THE USE OF NEW TECHNOLOGIES FOR NUTRITIONAL SAFETY

In this thesis five experimental studies were reported with the objective to improve the knowledge and provide new solutions for different and important aspects of dairy cow nutrition. The first trial was performed to examine the relationships between blood concentrations of fatty acids (NEFA), \u3b2-hydroxybutyrate (BHB) and \u3b1-tocopherol during the periparturient period in dairy cows. For the study 131 cows from 4 different farms, 2 in Italy and 2 in Greece were used. We determined blood concentrations of NEFA, BHB, and \u3b1- tocopherol at dry-off, at calving, and 30d postpartum. We found a weak correlation between NEFA and BHB throughout the periparturient period. Negative correlations between NEFA and \u3b1-tocopherol were highly significant at 30d postpartum and approached the level of significance at dry-off. However, both correlations became nonsignificant following the adjustment of \u3b1-tocopherol with cholesterol, indicating that the correlations were a reflection of changes in lipid transport. We found significant negative correlations between BHB and \u3b1- tocopherol after adjustment with cholesterol. The aims of the second research presented was to understand the effects of lactic acid bacteria (LAB) inoculation on fermentation products and quality of alfalfa and ryegrass silage and the use of thermal camera and electronic nose to evaluate the silage quality. Wilted ryegrass and alfalfa silage were inoculated with a commercial product containing Lactobacillus Rhamnosus and Lactobacillus Farciminis and stored in triplicate micro fermenters for each treatment. The silos were opened after 2, 5, 30, 60, 90 and 120 days and silages were collected and analyzed. The results obtained showed better acidification of treated silages with pH value lower in both alfalfa and ryegrass silages (P 640.01). Alfalfa silage has had higher content of lactic acid (P 640.01) with unexpected higher values of NH4 (P 640.01). In ryegrass silage the LAB concentration was lower in treated compared to control silage (P 640.01). Instead no significant difference of LAB concentration was observed between control and treated alfalfa silages. Strong negative correlation between pH and lactic acid 97% (P 640.01) and positive correlation between pH and LAB concentration 93% (P 640.01) were observed in alfalfa silage. The LAB concentration was positive correlated with pH value 94% (P 640.01). Significant but not strong negative correlation was observed between pH and NH4 33% (P 640.05). Probably due to the good quality of both treated and control silages no differences of temperature were observed. Although, different results were obtained between ryegrass and silage analysis the electronic nose showed promising ability to evaluate the silage quality but further studies will be needed to understand his ability to evaluate the silage quality. In the third experimental trial the combined use of thermal camera and electronic nose was evaluated for rapid assessment of unfavorable fermentations that can occur in a corn silage mass. From April to September, five sampling times were performed to collect silage samples. The thermal camera was used to detect the temperature. For all samples chemical analysis were performed to evaluate the silage quality and was used electronic nose to perform the off-flavors analysis. The silage quality remained constant and no differences were observed throughout the trial. Significant statistical differences were observed between samples with normal temperature and that with higher temperature for pH value (P<0.01), lactic acid (P<0.05). The off-flavors analysis showed the ability of electronic nose to distinguish the strong wrong fermentation. The results obtained showed that the use thermal camera and electronic nose can provide an indication of silage quality in short time and with low cost. Further studies aimed to study the accuracy of both instruments are necessary. The aim of the fourth experimental study was to investigate the physical quality of a selected lot of twenty animal feed samples collected in Italy and Serbia. The samples belonged to different categories and analyzed to assess the flowability, particle size distribution, hardness and durability. Granulation of cattle and pig feed was finer in Italian than in Serbian samples. Flowability of samples from both countries in mash form were rated from fair to good (angle of repose >30\ub0) while granulated samples (pellets and extrudates) had improved flowability (angle of repose 10 kg) than pelleted products (<8 kg). Durability of most of the extruded and pelleted products was higher tha 95%. Most of the physical characteristics of the samples responded to recommendations, which showed that the similar practices are in use in both countries. The last research reported in this thesis had the aim to determine the influence of filling level, cutting and mixing time on homogeneity and particle size distribution of a dairy cow total mixed ration (TMR). The mixing wagon was loaded to 40%, 70% and 100% of maximum nominal load (21m3). The cutting time and mixing time were 4, 5 and 6 minutes. Samples of TMR were collected at the beginning, in the middle and at the end of the feeding alley and analysed to evaluate the dry matter (DM), ether extract (EE), crude protein (CP), neutral detergent fibre (NDF), and ash content. At the same time TMR particle size distribution was determined in triplicate for each sampling point by Penn State Particle Separator. The coefficient of variation (CV %) of DM, CP, NDF and EE was used to evaluate the multiple effect of filling level, cutting and mixing time on ration uniformity and differences between the theoretical ration formulated and that provided to dairy cattle. The filling level was the main factor affecting uniformity and differences from theoretical ration, the best results were obtained to 70%. The mixing time had less and different effects uniformity and ration composition. The cutting time showed no effects

Quale normatività? Vita e malattia fra naturalismo e antiriduzionismo

Questo articolo si propone di illustrare i limiti e le implicazioni pratiche della teoria biostatistica formulata dal filosofo della scienza Christopher Boorse. La biostatistica infatti vuole fornire in ambito biomedico uno strumento concettuale che si presti alle esigenze operative della medicina; ricorrendo alla nozione di progetto di specie tale teoria pretende di oggettivare i concetti di normalità e di salute e di offrire una comprensione altrettanto oggettiva dei fenomeni patologici. Seguendo però le coordinate fornite dal neurofisiologo tedesco Kurt Goldstein (1878-1965) e i fondamentali contributi del filosofo francese Georges Canguilhem, si metterà in luce come i due concetti di normalità e patologia, centrali tanto per la teoria che per la pratica medica, non possano essere ricondotti esclusivamente al piano della spiegazione meccanicista delle dinamiche del vivente, poiché, esprimendo la plasticità della vita, tali concetti possono essere compresi meglio a partire dalla rete di rapporti che coinvolge gli individui e l’ambiente.This paper aims to illustrate not only practical, but even theoretical boundaries and implications in the biostatistic theory by the science philosopher Christopher Boorse. The biostatistic theory indeed conveys a conceptual instrument, which fits with operational needs of medicine; resorting to the notion of species design, this theory pretends to objectify the concepts of normality and health, so to provide an even more actual comprehension of disease phenomena. Following the guidelines given by the German neurophysiologist Kurt Goldstein (1878-1965), and the French philosopher Georges Canguilhem’s capital contribution, it will be highlighted how normality and pathology, key concepts as well in theoretical as in practical medicine, in the explanation field of the living being’s dynamics, cannot exclusively be reduced to a mechanistic level, because expressing the plasticity of life themselves, such concepts can be better understood by analyzing the relationship’s net which involves entities and environment

MITOCHONDRIAL MEMORY AT SKELETAL MUSCLE LEVEL

Mitochondria are key components of skeletal muscles as they provide the energy required for almost all cellular activities. Different forms of exercise training have been associated with mitochondrial adaptations, such as increased mitochondrial content and function, and enhanced mitochondrial biogenesis, as well as improved endurance performance. High-intensity interval training and sprint interval training have been demonstrated to be the most effective training modalities to induce mitochondrial adaptations. However, surprisingly, greater changes in mitochondrial content and biogenesis were also observed after repeated resistance training interventions separated by prolonged detraining. This mechanism, defined muscle memory, has been well established for hypertrophy and skeletal muscle growth in response to resistance training and it has been related to the retention of acquired myonuclei or epigenetic modifications. Thereby, even mitochondrial adaptations might be influenced by muscle memory, but it remains to be explored whether repeated endurance training interventions can rely on the same mechanism. Therefore, the overarching aim of the present thesis was to investigate the potential presence of mitochondrial memory in response to repeated high- intensity endurance training interventions. An experimental design composed of two periods of 8 weeks of interval training interspersed by 3 months of detraining was conducted on murine model and humans. In mice, maximal running velocity (Vmax) by graded exercise test (GXT) on a rodent treadmill. In addition, biomarkers of mitochondrial biogenesis and content, and fusion-fission mitochondrial key factors were analyzed on gastrocnemius muscle by western Blot. Results revealed that endurance performance improved to a greater extent after retraining than training. This functional adaptation was supported by a larger mitochondrial content resulting from a more pronounced mitochondrial biogenesis response after retraining. Mitochondrial dynamics were shifted mainly towards fusion, suggesting larger and more elongated mitochondria and finally, the retraining period elicited increased mitophagic flux, which, associated with a smaller increment in the amount of respiratory chain complexes, suggests an improvement in clearance of damaged mitochondria in order to ensure healthier mitochondria and more efficient respiratory function. In humans, maximal aerobic capacity and peak power output were measured and muscle sample from vastus lateralis was used for mitochondrial respiration and epigenetic analysis. Mitochondrial function resulted in a greater improvement after high intensity aerobic stimulus when previous exposure to an identical stimulus has been occurred separated by long-term period of stimulus cessation. The underlying mechanism could reside in epigenetic modifications induced by interval training which led to DNA hypomethylation. Two memory profiles were highlighted at epigenetic level characterized by retention of hypomethylation even during the prolonged detraining period and involving differentially methylated regions related with genes implicated in skeletal muscle metabolic pathways. Overall, these studies provided evidence for a skeletal muscle memory mechanism, specifically at mitochondrial level, elicited by high-intensity aerobic training that affects muscle aerobic phenotype initiating at the epigenetic level and extends upstream to affect mitochondrial function and endurance performance

The fuzzy bag and baryonic properties with center of mass and recoil corrections

The fuzzy bag is a hadronic model which has features both of the bag model (energy-momentum conservation, QCD vacuum energy) and of relativistic potential models (confinement achieved through a potential). It is also a chiral model, with the unique property that the pion field is suppressed in the interior of the bag by means of a scalar potential, and yet chiral symmetry is preserved. This scalar potential allows one to control how far the pion field can penetrate in the interior of the bag. We calculate the masses of the fundamental baryon octet taking into account the center of mass, one-gluon exchange and one-pion exchange corrections. We also calculate the nucleon axial charge, charge radii and magnetic moments including center of mass and recoil corrections. The agreement with experiment is excellent, and the results indicate that the pion field is suppressed only very close to the center of the bag

Stochastic filtering in jump systems with state dependent mode transitions

We introduce a new methodology to construct a Gaussian mixture approximation to the true filter density in hybrid Markovian switching systems. We relax the assumption that the mode transition process is a Markov chain and allow it to depend on the actual and unobservable state of the system. The main feature of the method is that the Gaussian densities used in the approximation are selected as the solution of a convex programming problem which trades off sparsity of the solution with goodness of fit. A meaningful example shows that the proposed method can outperform the widely used interacting multiple model (IMM) filter in terms of accuracy at the expenses of an increase in computational time

Augustana Seniors Fall 1884: August William Kjellstrand

August William Kjellstrand was a senior at Augustana College, Rock Island, Illinois, in the fall of 1884. His name appears in the college catalog of 1884 – 1885, along with his birthplace, the year of his birth, and a few other facts. From this start, we researched the genealogy and family history of A. W. Kjellstrand. This paper contains a short biography of A. W. Kjellstrand, a report on his ancestors, a report on his descendants, and some open questions for further research