Context-Aware Handover Policies in HetNets

Next generation cellular systems are expected to entail a wide variety of wireless coverage zones, with cells of different sizes and capacities that can overlap in space and share the transmission resources. In this scenario, which is referred to as Heterogeneous Networks (HetNets), a fundamental challenge is the management of the handover process between macro, femto and pico cells. To limit the number of handovers and the signaling between the cells, it will hence be crucial to manage the user's mobility considering the context parameters, such as cells size, traffic loads, and user velocity. In this paper, we propose a theoretical model to characterize the performance of a mobile user in a HetNet scenario as a function of the user's mobility, the power profile of the neighboring cells, the handover parameters, and the traffic load of the different cells. We propose a Markov-based framework to model the handover process for the mobile user, and derive an optimal context-dependent handover criterion. The mathematical model is validated by means of simulations, comparing the performance of our strategy with conventional handover optimization techniques in different scenarios. Finally, we show the impact of the handover regulation on the users performance and how it is possible to improve the users capacity exploiting context information

A Bayesian multi-factor model of instability in prices and quantities of risk in U.S. financial markets

This paper analyzes the empirical performance of two alternative ways in which multi-factor models with time-varying risk exposures and premia may be estimated. The first method echoes the seminal two-pass approach advocated by Fama and MacBeth (1973). The second approach extends previous work by Ouysse and Kohn (2010) and is based on a Bayesian approach to modelling the latent process followed by risk exposures and idiosynchratic volatility. Our application to monthly, 1979-2008 U.S. data for stock, bond, and publicly traded real estate returns shows that the classical, two-stage approach that relies on a nonparametric, rolling window modelling of time-varying betas yields results that are unreasonable. There is evidence that all the portfolios of stocks, bonds, and REITs have been grossly over-priced. On the contrary, the Bayesian approach yields sensible results as most portfolios do not appear to have been misspriced and a few risk premia are precisely estimated with a plausibile sign. Real consumption growth risk turns out to be the only factor that is persistently priced throughout the sample.Econometric models ; Stochastic analysis ; Financial markets

Morse inequalities for the Koszul complex of multi-persistence

In this paper, we define the homological Morse numbers of a filtered cell complex in terms of the relative homology of nested filtration pieces and derive inequalities relating these numbers to the Betti tables of the multi-parameter persistence modules of the considered filtration. Using the Mayer-Vietoris spectral sequence we first obtain strong and weak Morse inequalities involving the above quantities, and then we improve the weak inequalities achieving a sharp lower bound for phonological Morse numbers. Furthermore, we prove a sharp upper bound for homological Morse numbers, expressed again in terms of the Betti tables

Anatomical study of the pre-segmental and segmental arteries of the kidney and their impact in the nephronsparing surgery

Clamping of the main renal artery (RA) is still regarded as a commonly used technique to decrease haemorrhage in partial nephrectomy, but it causes warm ischaemic injury. The aim of this study was to describe the pattern of pre-segmental and segmental branches of the RA. To obtain vascular corrosions casts, twenty kidneys were injected with acrylic resins and underwent to computed tomography examination. Analysis of images and of casts showed that the pattern of vascularisation of posterior renal segment was constant (except that in one case), presenting one segmental artery. The vascularisation of the anterior parenchyma (apical, superior, middle and inferior segments) originated directly from an anterior branch of the RA (70%) or thorough pre-segmental arteries (PSA) (30%). In 20% two middle segmental artery originated from two different PSAs. A series of vascular renal patterns have been identified, that the surgeon must know before to conduct the selective clamping, i.e. the selective clamping of segmental artery originating from a PSA could more difficult, because the surgeon can wrongly close the PSA with subsequent ischemia of the more parenchymal segments. Moreover, in case of multiple segmental arteries, originating from two PSA, the surgeon can wrongly clamp only one of them with subsequent intraoperative hemorrhage

SHBG(141-161) Domain-Peptide Stimulates GPRC6A-Mediated Response in Leydig and \u3b2-Langerhans cell lines

GPRC6A is acknowledged as a major regulator of energy metabolism and male fertility through the action of undercarboxylated osteocalcin (ucOCN), representing a possible therapeutic target. We recently showed that the sex hormone-binding globulin (SHBG) binds to GPRC6A through the likely involvement of the 141-161 domain. To confirm this model, here we investigated the possible binding and agonist activity of SHBG(141-161) domain-peptide (SHBG141-161) on GPRC6A. The binding of SHBG141-161 to GPRC6A and downstream dissociation from G\u3b1i(GDP) protein was computationally modelled. SHBG141-161 was obtained by solid-phase synthesis, characterized by circular dichroism (CD) and the receptor binding was assessed by displacement of ucOCN on HEK-293 cells transfected with GPRC6A gene. Agonist activity of SHBG141-161 was assessed on Leydig MA-10 and Langerhans \uf062-TC6 cell lines through the GPRC6A-mediated release of testosterone (T) and insulin. SHBG141-161 was predicted to bind to GPRC6A and to reduce the affinity for G\u3b1i(GDP) at computational level. Conformational properties and binding to GPRC6A of the synthetic SHBG141-161 were confirmed by CD and displacement experiments. SHBG141-161 stimulated cell secretion of T and insulin, with dose dependency from 10-13 to 10-11M for T release (respectively P=0,041 10-13M; P = 0,032 10-12M; P = 0,008 10-11M vs basal) and for 10-12 to 10-10M for insulin (respectively P=0,041 10-12M; P=0,007 10-11M; P=0,047 10-10M; P=0,045 vs basal). Blockade with anti GPRC6A IgG abolished the response to SHBG141-161, suggesting agonist specificity. SHBG141-161 showed stimulating activity on GPRC6A, representing a template peptide with possible therapeutic use for metabolic and endocrine disorder

Vessels of the umbilical cord: an anatomo-microscopic study in normal and pathological newborns

Intrauterine growth restriction (IUGR) due to placental insufficiency is associated with blood-flow redistribution. Placental insufficiency in late-onset IUGR often goes undetected by umbilical artery Doppler scan. Despite a broad general body of literature referencing placentas of IUGR pregnancies, there are no report on the structural characteristics of the vessels of the umbilical cord in IUGR. Thus, the aim of the present study was to compare the microscopic anatomy of the umbilical arteries and veins in normal, IUGR and small for gestational age (SGA) newborns. Twenty six umbilical cords were taken from 10 IUGR, 5 SGA, and 11 controls newborns. The histological and morphological examination was performed with EE, Azan–Mallory, Sirius Red stains and morphometric evaluation was performed through a computer image analysis approach. In the controls, the umbilical artery shows a muscular tunica, organized by two layers, an outer one with circularly arranged cells, and an inner one, with irregularly arranged cells. In the IUGR longitudinal muscular fibers are observable. In IUGR the percentage of the muscular fibers of the umbilical artery was greater with respect of SGA and controls. In IUGR and SGA the percentage of the muscular fibers was minor with respect to controls. In the umbilical artery in IUGR and SGA the elastic fibers and collagen I was major and collagen III was minor with respect to SGA. In the umbilical vein the collagen III was major in IUGR and SGA with respect to controls. These data agree with those of intrauterine life, in which a major thickness of the abdominal aortic wall was observed in fetuses with abnormalities of Doppler flussimetry. The rearrangement of umbilical artery may affect the mechanical properties of these vessels and disturb fetal blood circulation

Dermal papillae flattening of thigh skin in Conus Cauda Syndrome

Our previous studies have shown that severely atrophic Quadriceps muscles of spinal cord injury (SCI) persons suffering with complete conus and cauda equina syndrome, and thus with permanent denervation-induced atrophy and degeneration of muscle, were almost completely rescued to normal size after two years of home based Functional Electrical Stimulation (hbFES). Since large surface electrodes were used to stimulate the denervated thigh muscles, we wanted to know if the skin was affected by this peculiar long-term treatment. Indeed, we demonstrated by two approaches that the epidermis decreases in thickness in the long term denervated persons, while it increased to almost pre-SCI values in hbFES compliant SCI persons. Here we report data of morphometry of skin biopsies from both legs of 18 SCI persons, harvested at enrolment in the Project RISE, to test if the Interdigitation Index, a simple measurement of the epidermal‐dermal junction, may provide a further precise quantitative evidence of the flattening of the skin in those SCI persons. The Interdigitation Index of the 36 skin biopsies shows a higly significant linear correlation with the years of SCI (p < 0.001). Furthermore, when the 18 SCI persons are divided in two groups (1 to 3.9 versus 4.1 to 8.0 years from SCI, respectively) and the data are compared, the later Group presents a statistically significant -22% decrease (p, 0.029) of the Interdigitation Index. On the other hand counting the papille do not provide the same strong evidence. In conclusion, the Interdigitation Index is an additional sound quantitative structural biomarker of skin atrophy and flattening occurring in SCI. The result correlates with the much severe extent of atrophy of the permanently denervated thigh muscles, as determined at both macro and microscopic levels.We are confident that the Interdigitation Index will provide sound evidence that the effects of hbFES, we previously reported on skeletal muscle and epidermis thickness, will be extended to the dermal layer of the skin, suggesting a coordinated negative effects of SCI on skeletal muscle and skin, and an improvement of both tissues after hbFES. Incoming analyses will be extended to basal lamina, collagene types, elastic fibers and skin annexes in the subcutaneous layer

Nanoscale battery cathode materials induce DNA damage in bacteria

The increasing use of nanoscale lithium nickel manganese cobalt oxide (LixNiyMnzCo1−y−zO2, NMC) as a cathode material in lithium-ion batteries poses risk to the environment. Learning toxicity mechanisms on molecular levels is critical to promote proactive risk assessment of these complex nanomaterials and inform their sustainable development. We focused on DNA damage as a toxicity mechanism and profiled in depth chemical and biological changes linked to DNA damage in two environmentally relevant bacteria upon nano-NMC exposure. DNA damage occurred in both bacteria, characterized by double-strand breakage and increased levels of many putative chemical modifications on bacterial DNA bases related to direct oxidative stress and lipid peroxidation, measured by cutting-edge DNA adductomic techniques. Chemical probes indicated elevated intracellular reactive oxygen species and transition metal ions, in agreement with DNA adductomics and gene expression analysis. By integrating multi-dimensional datasets from chemical and biological measurements, we present rich mechanistic insights on nano-NMC-induced DNA damage in bacteria, providing targets for biomarkers in the risk assessment of reactive materials that may be extrapolated to other nano–bio interactions

High-quality digital 3D reconstruction of the terminal pathway of a heart stab wound

High-quality digital 3D reconstructions of microscopic findings have been involved in anatomical and histopathological research, but their potentialities in forensic pathology may also be of particular interest. We here present the use of such methods to furtherly analyse a heart stab wound in a suicidal case. External examination revealed multiple incised wounds on the wrists, three stab wounds at the neck and a single stab wound on the chest. At autopsy, injuries to the neck and wrists were superficial whereas the thoracic stab wound penetrated the chest wall and pericardium. Heart examination showed an 8-mm-long stab wound on the anterior surface of the left ventricle. Heart sectioning and inspection of the correspondent internal aspect of the left ventricle did not show a macroscopic injury, but the irregularity of the trabeculae carneae did not permit to exclude a microscopic pathway. Thus, the heart wall including the stab wound was paraffin-embedded and subjected to complete sectioning for microscopic analysis along all the wound extension. Every 10th section was stained with haematoxylin-eosin and was acquired by using a Leica DMR microscope and a high resolution digital camera. The three-dimensional aspect of the lesion was reconstructed with a software system for 3D computer graphics. Microscopic examination and 3D reconstruction demonstrated that the lesion extended to the internal surface of the ventricle wall, although for a very limited extension. 3D reconstruction also showed a certain curvilinear pattern of the lesion in the myocardium, consistent with myocardial contraction at the moment of injury and consequent vitality of the lesion. Moreover, 3D reconstruction permitted to obtain the dimensions of the intra-myocardial injury (corrected for shrinkage and evaluated in the context of muscle contraction), also permitting to furtherly confirm the identification of the knife involved. In conclusion, the present case is indicative of how complete microscopic sectioning and 3D reconstruction may add further information about characteristics of injuries of forensic interest

Early Embryonic Vascular Patterning by Matrix-Mediated Paracrine Signalling: A Mathematical Model Study

During embryonic vasculogenesis, endothelial precursor cells of mesodermal origin known as angioblasts assemble into a characteristic network pattern. Although a considerable amount of markers and signals involved in this process have been identified, the mechanisms underlying the coalescence of angioblasts into this reticular pattern remain unclear. Various recent studies hypothesize that autocrine regulation of the chemoattractant vascular endothelial growth factor (VEGF) is responsible for the formation of vascular networks in vitro. However, the autocrine regulation hypothesis does not fit well with reported data on in vivo early vascular development. In this study, we propose a mathematical model based on the alternative assumption that endodermal VEGF signalling activity, having a paracrine effect on adjacent angioblasts, is mediated by its binding to the extracellular matrix (ECM). Detailed morphometric analysis of simulated networks and images obtained from in vivo quail embryos reveals the model mimics the vascular patterns with high accuracy. These results show that paracrine signalling can result in the formation of fine-grained cellular networks when mediated by angioblast-produced ECM. This lends additional support to the theory that patterning during early vascular development in the vertebrate embryo is regulated by paracrine signalling