Nodes Placement for reducing Energy Consumption in Multimedia Transmissions

International audiencePower consumption is an essential issue in wireless multimedia sensor networks (WMSNs) due to the elevated processing capabilities requested by the video acquisition hardware installed on the generic sensor node. Hence, node placement scheme in WMSNs greatly impacts the overall network lifetime. In this context, the paper first proposes a suitable hardware architecture to implement a feasible WMS node based on off-the-shelf technology, then it evaluates the energy consumption obtained throughout a wise "energy-spaced" placement of the wireless nodes without affecting the video quality of multimedia traffic

Agnosic vision is like peripheral vision, which is limited by crowding

Abstract Visual agnosia is a neuropsychological impairment of visual object recognition despite near-normal acuity and visual fields. A century of research has provided only a rudimentary account of the functional damage underlying this deficit. We find that the object-recognition ability of agnosic patients viewing an object directly is like that of normally-sighted observers viewing it indirectly, with peripheral vision. Thus, agnosic vision is like peripheral vision. We obtained 14 visual-object-recognition tests that are commonly used for diagnosis of visual agnosia. Our "standard" normal observer took these tests at various eccentricities in his periphery. Analyzing the published data of 32 apperceptive agnosia patients and a group of 14 posterior cortical atrophy (PCA) patients on these tests, we find that each patient's pattern of object recognition deficits is well characterized by one number, the equivalent eccentricity at which our standard observer's peripheral vision is like the central vision of the agnosic patient. In other words, each agnosic patient's equivalent eccentricity is conserved across tests. Across patients, equivalent eccentricity ranges from 4 to 40 deg, which rates severity of the visual deficit. In normal peripheral vision, the required size to perceive a simple image (e.g., an isolated letter) is limited by acuity, and that for a complex image (e.g., a face or a word) is limited by crowding. In crowding, adjacent simple objects appear unrecognizably jumbled unless their spacing exceeds the crowding distance, which grows linearly with eccentricity. Besides conservation of equivalent eccentricity across object-recognition tests, we also find conservation, from eccentricity to agnosia, of the relative susceptibility of recognition of ten visual tests. These findings show that agnosic vision is like eccentric vision. Whence crowding? Peripheral vision, strabismic amblyopia, and possibly apperceptive agnosia are all limited by crowding, making it urgent to know what drives crowding. Acuity does not (Song et al., 2014), but neural density might: neurons per deg2 in the crowding-relevant cortical area

The influence of platform switching on the biomechanical aspects of the implant-abutment system. A three dimensional finite element study

Objective: To evaluate the biomechanical scenario of platform switching geometric implant-abutment configuration relative to standard configurations by means of finite element analysis.Study Design: A 3D Finite Element Analysis (FEA) was performed on 3 different implant-abutment configurations: a 3.8 mm implant with a matching diameter abutment (Standard Control Design, SCD), a 5.5 mm implant with matching diameter abutment (Wider Control Design, WCD), and a 5.5mm implant with a 3.8 mm abutment (Experimental Design, ED). All the different experimental groups were discretized to over 60000 elements and 100000 nodes, and 130N vertical (axial) and 90N horizontal loads were applied on the coronal portion of the abutment. Von Mises stresses were evaluated and maximum and minimum values were acquired for each implantabutment configuration. Results: The load-induced Von Mises stress (maximum to minumum ranges) on the implant ranged from 150 MPa to 58 Pa (SCD); 45 MPa to 55 Pa (WCD); 190 MPa to 64 Pa (ED). The Von Mises stress on the abutment ranged from 150 MPa to 52 MPa (SCD); 70 MPa to 55 MPa (WCD), and 85 MPa to 42 MPa respectively (ED). The maximum stresses transmitted from the implant-abutment system to the cortical and trabecular bone were 67 Pa and 52 MPa (SCD); 54 Pa and 27 MPa (WCD); 64 Pa and 42 MPa (ED), respectively. When the implant body was evaluated for stresses, a substantial decrease in their levels were observed at the threaded implant region due to the diametral mismatch between implant and abutment for the ED configuration. Conclusion: The platform switching configuration led to not only to a relative decrease in stress levels compared to narrow and wide standard configurations, but also to a notable stress field shift from bone towards the implant system, potentially resulting in lower crestal bone overloading. © Medicina Oral S. L

The influence of platform switching on the biomechanical aspects of the implant-abutment system. A three dimensional finite element study

Objective: To evaluate the biomechanical scenario of platform switching geometric implant-abutment configuration relative to standard configurations by means of finite element analysis.Study Design: A 3D Finite Element Analysis (FEA) was performed on 3 different implant-abutment configurations: a 3.8 mm implant with a matching diameter abutment (Standard Control Design, SCD), a 5.5 mm implant with matching diameter abutment (Wider Control Design, WCD), and a 5.5mm implant with a 3.8 mm abutment (Experimental Design, ED). All the different experimental groups were discretized to over 60000 elements and 100000 nodes, and 130N vertical (axial) and 90N horizontal loads were applied on the coronal portion of the abutment. Von Mises stresses were evaluated and maximum and minimum values were acquired for each implantabutment configuration. Results: The load-induced Von Mises stress (maximum to minumum ranges) on the implant ranged from 150 MPa to 58 Pa (SCD); 45 MPa to 55 Pa (WCD); 190 MPa to 64 Pa (ED). The Von Mises stress on the abutment ranged from 150 MPa to 52 MPa (SCD); 70 MPa to 55 MPa (WCD), and 85 MPa to 42 MPa respectively (ED). The maximum stresses transmitted from the implant-abutment system to the cortical and trabecular bone were 67 Pa and 52 MPa (SCD); 54 Pa and 27 MPa (WCD); 64 Pa and 42 MPa (ED), respectively. When the implant body was evaluated for stresses, a substantial decrease in their levels were observed at the threaded implant region due to the diametral mismatch between implant and abutment for the ED configuration. Conclusion: The platform switching configuration led to not only to a relative decrease in stress levels compared to narrow and wide standard configurations, but also to a notable stress field shift from bone towards the implant system, potentially resulting in lower crestal bone overloading. © Medicina Oral S. L

Sensitivity Analysis for a PEM Fuel Cell Model aimed to Optimization

The amount of current density produced by the stack is the key performance parameter for a fuel cell, given a well-defined quantity of reactants flowing through it. A Proton Exchange Membrane fuel cell (PEMFC) distributed parameters model is considered with all the aspects influencing the cell behavior. A sensitivity analysis is performed through a Monte Carlo Simulation to assess the impact on performances of key parameters. The Pareto plot obtained from such analysis allow to operate design variables reduction, aimed to those parameters that show small impact, so to decrease the problem complexity through an increased orthogonality of the input design matrix. The target of the activity is to obtain and validate a method able to reduce the time needed for a complete simulation, so to be able to realize an effective multi-disciplinary design optimization

Evolving management of adolescent varicocele

OBJECTIVE: To review the evolution in indications for treatment and treatment modalities for adolescent varicocele at our centre, and evaluate the impact of varicocelectomy on final outcome. PATIENTS AND METHODS: Between 1995 and 2006, we treated 242 left varicoceles. Preoperative assessment included clinical evaluation, measurement of testicular volumes, and colour-Doppler ultrasound (CDUS). A subinguinal varicocelectomy was performed in 124 patients (group A), and a laparoscopic non-artery-sparing Palomo procedure in the remaining 118 (group B). In group B patients, CDUS was also used to investigate the functional anatomy of varicocele, and all the veins found to be refluxing were divided during surgery. The two groups were compared with regard to indications for surgery and outcome. RESULTS: Over time the proportion of patients operated on because of testicular growth retardation increased. Persistence/recurrence rate was comparable between the two groups. In 13% of group B patients, the deferential vein was found to be refluxing on preoperative CDUS and was divided at surgery. Hydrocele rate was higher in group A, unless the vaginalis was excised and everted during varicocelectomy. About 75% of patients with preoperative left testicular growth failure experienced postoperative catch-up growth, irrespective of treatment. CONCLUSION: Indications for treatment are still evolving. Varicocele can successfully be treated in the majority of cases by either a laparoscopic or subinguinal approach. Both techniques require care, and CDUS can aid in the decision making. Most patients with preoperative testicular growth failure experience postoperative catch-up growth

Evaluation of esophageal motility using multichannel intraluminal impedance in healthy children and children with gastroesophageal reflux: comments

Abstract OBJECTIVE: : Multichannel intraluminal impedance (MII) directly evaluates esophageal bolus transport. There is a good correlation between MII and manometry in healthy adults, but there are no reports concerning children.The aim of the present study was to determine normal values of esophageal motility using only impedance measurements in healthy children and in a pediatric population with gastroesophageal reflux (GER). PATIENTS AND METHODS: : We described in the present study 60 children submitted to pH-MII for 24 hours for suspected GER. Patients were divided into 2 different groups on the basis of their pH-MII report. Group 1 patients showed acid GER, whereas group 2 patients had negative pH-MII analysis for GER despite symptoms. We described impedance reflux and motility parameters on 10 standardized swallows: number of reflux, mean acid clearing time, median bolus clearing time, bolus presence time, total bolus transit time, segmental transit time, and total propagation velocity. RESULTS: : In group 1, the median mean acid clearing time was 151 seconds, whereas the median mean bolus clearing time was 25 seconds. In group 2 patients, all of the reflux parameters were normal. In group 1 the median bolus presence time at each measuring site, the median total bolus transit time, and the median segmental transit time were significantly greater and total propagation velocity lower than values reported in group 2 (P < 0.001), if compared with those described for adult patients. CONCLUSIONS: : The pH-MII is an ideal test in children because it studies GER with its characteristics and motility pattern. Our report summarizes for the first time impedance motility parameters in healthy children

Effects of parietal lesions in humans on color and location priming

To determine whether the parietal lobes contribute to the selection of nonspatial features known to be processed in the ventral stream, the current study examined the effect of chronic unilateral parietal lobe lesions in humans on color and location priming. Patients and normal controls performed a go/no-go color discrimination task in which either the same color and different color pairs of stimuli (prime and probe) were projected sequentially either in the same hemifield or in opposite hemifields. Control subjects and patients both showed independent effects of color and location priming. In the patients, primes in either field produced color priming for target probes in the ipsilesional field but not for probes in the contralesional field. This observation implicates the parietal cortex in processing activated codes of stimulus attributes not only for spatial information but also for visual features processed in the ventral visual pathways

A simple technique of oblique anastomosis can prevent stricture formation in primary repair of esophageal atresia

Background: Anastomotic stricture is an important problem after esophageal atresia (EA) repair. This study evaluates a technique of oblique esophageal anastomosis without use of a flap in order to prevent stricture formation. Methods: Medical records of 16 patients (14 with EA type III and 2 with EA type IV Ladd-Gross classification) who underwent primary repair of EA at birth without anastomotic tension were reviewed, evaluating long-term follow-up results. All patients were studied with esophageal contrast study, pH-multichannel intraluminal impedance, and endoscopy. The incidence of complications and their management were analysed. Results: Contrast esophagogram and esophagoscopy always showed regular patency of the suture line. Conclusions: Our technique of oblique anastomosis is simple, safe, and effective in preventing stricture formation even in the long-term follow-up