Valutazione delle prestazioni di sistemi WiFi per reti veicolari

Le prestazioni di sistemi WiFi usati in reti veicolari per trasferire dati tra veicoli in movimento ed Internet dipendono sia dalla topologia dei punti di accesso a bordo strada che dalla mobilità dei veicoli. L'obiettivo di questa tesi è di valutare tramite un simulatore di rete, ed usando tracce realistiche di mobilità veicolare, le prestazioni di tali sistemi WiFi considerando diverse politiche di posizionamento di un limitato numero di punti di accesso in un'area urbana

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

Efficacy of periportal infiltration and intraperitoneal instillation of ropivacaine after laparoscopic surgery in children

Postoperative pain is less intense after laparoscopic than after open surgery. However, minimally invasive surgery is not a a pain-free procedure. Many trials have been done in adults using intraperitoneal and/or incisional local anesthetic, but similar studies have not yet been reported in the literature in children. Aim: The aim of this study was to evaluate the analgesic effect of periportal infiltration and intraperitoneal instillation of ropivacaine in children undergoing laparoscopic surgery. Materials and Methods: Thirty patients who underwent laparoscopic surgery were randomly allocated to one of three groups. Group A (n 10) received local infiltration of port sites with 10 mL of ropivacaine. Group B (n 10) received both an infiltration of port sites with 10 mL of ropivacaine and an intraperitoneal instillation of 10 mL of ropivacaine. Group C did not receive any analgesic treatment. The local anesthetic was always administered at the end of surgery. The degree of postoperative abdominal parietal pain, abdominal visceral pain, and shoulder pain was assessed by using a Wong-Baker pain scale and a Visual Analog Scale (VAS) at 3, 6 12, and 24 hours postoperatively. The following parameters were also evaluated: rescue analgesic treatment, length of hospital stay, and time of return to normal activities. Results: Three hours after operation, patients had low pain scores. Six and 12 hours postoperatively, the abdominal parietal pain was significantly higher (P 0.0005) in group C than in the other two groups, both treated with an infiltration at the trocar sites; mean intensity of abdominal visceral pain was significantly lower (P 0.0005) in group B than in groups A and C; the overall incidence of shoulder pain was significantly lower (P 0.0005) in group B patients than in patients of groups A and C. At 20 hours postoperatively, pain scores were significantly reduced of intensity in all groups. Rescue analgesic treatment was significantly higher in group C, if compared to groups A and B 12 hours after the operation. No statistically significant difference was found in length of hospital stay, but children who received analgesic treatment had a more rapid return to normal activities than untreated patients (P 0.0005). Conclusions: Our study demonstrates that the combination of local infiltration and intraperitoneal instillation of ropivacaine is more effective for pain relief in children after laparoscopic surgery than the administration of ropivacaine only at the trocar sites

CALCAREOUS PLANKTON HIGH RESOLUTION BIOSTRATIGRAPHY (FORAMINIFERA AND NANNOFOSSILS) OF THE UPPERMOST LANGHIAN – LOWER SERRAVALLIANRAS IL-PELLEGRIN SECTION (MALTA)

Results of an integrated biostratigraphic (calcareous nannofossils and planktonic foraminifers) study of the uppermost Langhian/lower Serravallian Ras il-Pellegrin section (Fomm ir-Rih Bay – Malta) are presented. This high resolution study allowed us to recognise several useful lower Serravallian bio-events in the Mediterranean and to provide a detailed distribution pattern of the recognised taxa. The astrochronological calibration, reported in a different paper of this volume, provided absolute ages of the bio-events of the studied section. The LO (Last Occurrence) of Globorotalia peripheroronda at 13.39 Ma, the Paragloborotalia partimlabiata FO (First Occurrence) at 12.62 Ma and the Paragloborotalia mayeri FCO (First Common Occurrence) at 12.34 Ma among the planktonic foraminifera, and the Sphenolithus heteromorphus LO at 13.59 Ma, the Cyclicargolithus floridanus LCO (Last Common Occurrence) at 13.39 Ma, the Reticulofenestra pseudoumbilicus FCO at 13.32 Ma, the Calcidiscus macintyrei FO at 12.57 Ma and the Calcidiscus premacintyrei LCO at 12.51 Ma among the calcareous nannofossils, were recorded. Moreover, our results confirm the LO of S. heteromorphus as a fairly synchronous event in the Mediterranean and in the Atlantic and Pacific Oceans. Therefore, we suggest a lithological level near or coincident with this event for the definition of the GSSP of the Serravallian. The Ras il-Pellegrin section may be considered a good candidate for this definition.&nbsp

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

CALCAREOUS PLANKTON BIO-EVENTS IN THE MIOCENECASE PELACANI SECTION (SOUTH-EASTERN SICILY, ITALY)

The upper Serravallian-Lower Tortonian Case Pelacani section in Sicily is represented by the epipelagic sediments of the Tellaro Formation. Along the section, which was sampled in four easily correlatable segments, a more or less continuous sequence of lithologic couplets, with whitish marls and blackish levels in the lower part and whitish marls and whitish more indurated levels in the upper part are present. The distribution of the most common taxa of planktonic foraminifera and calcareous nannofossils was quantitatively estimated in 316 samples, collected every 20 cm along the section which is 66.35 m thick. This allowed to identify eleven planktonic foraminifera (but only the eight marker events were quantitatively estimated) and five calcareous nannofossil bio-events.&nbsp; Their astrochronology is reported by correlation with the cyclostratigraphic results obtained for this section in a different paper. The ages are well comparable with the ages published for the same events in other Mediterranean sections. Paleomagnetic analysis along 30 meters in the central part of the section gave puzzling results and therefore no reliable magnetostratigraphy could be obtained. The Case Pelacani section, straddling the stratigraphic interval between slightly below the first occurrence and slightly above the first regular occurrence of Neogloboquadrina acostaensis , is a good candidate for the definition of the GSSP (Global Stratigraphic Section and Point) of the Tortonian. Independently from the selected section, we suggest to define the Serravallian/Tortonian boundary in a level coincident or near the last occurrence of Paragloborotalia siakensis, as already proposed, or coincident with or near the last common occurrence of Globigerinoides subquadratus. This latter level virtually coincides with the first common occurrence of Globigerinoides obliquus obliquus and is slightly above the last common occurrence of Discoaster kugleri, which occurs only 2.25 meters (and 3 precessional cycles) below in the studied section.&nbsp

ASTROCHRONOLOGICAL CALIBRATION OF THE UPPER SERRAVALLIAN/LOWER TORTONIAN SEDIMENTARY SEQUENCE AT TREMITI ISLANDS(ADRIATIC SEA, SOUTHERN ITALY)

A high resolution cyclostratigraphic study was carried out on a cyclicaly bedded succession of late Middle Miocene deep marine deposits from the Tremiti Islands, Adriatic sea (Italy). Astronomical calibration of the sedimentary cycles provides absolute ages for different calcareous plankton bioevents, widely used for intra Mediterranean correlation, in the interval between 11.12 and 12.60 Ma. The sedimentary record of the S. nicola composite section consists of an alternation of indurated, withish coloured, CaCo3 rich and grey less indurated, CaCo3 poor marly beds, at times replaced by red coloured CaCo3 poor marls. Results of direct correlation between the La 90 (1,1) solution of the insolation curve and the cyclic lithologic patterns occurring in the studied sections, combined with results of spectral methodologies applied on the climate sensitive data (CaCo3 and Globigerinoides) showed that the classic Milankovitch periodicity can be represented through the modulation forcing of the studied sedimentary records.&nbsp

AN INTEGRATED CALCAREOUS PLANKTON BIOSTRATIGRAPHIC SCHEME AND BIOCHRONOLOGY FOR THE MEDITERRANEAN MIDDLE MIOCENE

The relative position of 30 main bioevents&nbsp; pertaining to calcareous nannofossils and planktonic foraminifera was identified in the time interval between 13.75 Ma and 10.50 Ma, based on the quantitative study of the those microfossils in three Mediterranean sections spanning the late Langhian – lower Tortonian stratigraphic interval. The events were correlated&nbsp; to the astronomic target curve using a cyclostratigraphic approach, resulting in a very detailed biostratigraphic and biochronologic subdivision of the interval. The zonal scheme proposed by Fornaciari et al. (1996) was adopted for the calcareous nannofossils, but three subzones were identified in the MMN7 Zone. For the planktonic foraminifera reference is made to the zonal scheme recently proposed by Foresi et al. (1998), slightly modified in order to increase its biostratigraphic resolution. The age of all the zonal boundaries is reported.&nbsp