365 research outputs found

    Implementation and analysis of location-based routing protocols for manets

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    This thesis concerns routing protocols for MANETs with a particular focus on location-based ones. After a deep overview of the literature, one regular routing protocol, DYMO, and two location-based (LB) ones, DYMOselfwd and AODV-Line, have been selected for further study. To this end, they have been implemented and simulated with the OMNET++ simulator. The scenarios are chosen to evaluate the impact of the node density, the nodes' mobility behaviour and of the ping payload on the performance of the routing protocols, in terms of scalability and ability to recover from route disruptions in a mobile scenario. In addition, the impact of an error in the location information is also analysed in the case of the two LB protocols

    The role of the distribution platform in price formation of paid apps

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    In this paper we study the role of the distribution platform as an important determinant of price of paid apps. We also examine how the distribution platform influences the price implications of important developers' app-level decisions. To these purposes, we construct a hierarchical model of price formation by using an ad-hoc panel dataset consisting of top paid apps from the two major app stores, namely Apple's App Store and Google Play. Our findings show that prices of paid apps strongly depend on the platform where the apps are marketed. Specifically, the App Store is associated with lower prices for paid apps than Google Play. We find evidence that this is because the impact of cross-store differences in developer competition prevails over the impact of cross-store differences in average consumer willingness to pay. We also find that the price premiums as a return to trialability are more likely to emerge in Google Play than in the App Store, and that developers are more likely to adopt a penetration price policy in Google Play, thus implying an influence of the distribution platform on the price implications of these app-level decisions. Finally, our evidence does not confirm the argument that a more marked price reduction for paid apps embedding ads or generating revenues from other interested third parties should be observed in Google Play

    Weakly Markov categories and weakly affine monads

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    Introduced in the 1990s in the context of the algebraic approach to graph rewriting, gs-monoidal categories are symmetric monoidal categories where each object is equipped with the structure of a commutative comonoid. They arise for example as Kleisli categories of commutative monads on cartesian categories, and as such they provide a general framework for effectful computation. Recently proposed in the context of categorical probability, Markov categories are gs-monoidal categories where the monoidal unit is also terminal, and they arise for example as Kleisli categories of commutative affine monads, where affine means that the monad preserves the monoidal unit. The aim of this paper is to study a new condition on the gs-monoidal structure, resulting in the concept of weakly Markov categories, which is intermediate between gs-monoidal categories and Markov ones. In a weakly Markov category, the morphisms to the monoidal unit are not necessarily unique, but form a group. As we show, these categories exhibit a rich theory of conditional independence for morphisms, generalising the known theory for Markov categories. We also introduce the corresponding notion for commutative monads, which we call weakly affine, and for which we give two equivalent characterisations. The paper argues that these monads are relevant to the study of categorical probability. A case at hand is the monad of finite non-zero measures, which is weakly affine but not affine. Such structures allow to investigate probability without normalisation within an elegant categorical framework.Comment: CALCO 202

    Weakly Markov Categories and Weakly Affine Monads

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    Introduced in the 1990s in the context of the algebraic approach to graph rewriting, gs-monoidal categories are symmetric monoidal categories where each object is equipped with the structure of a commutative comonoid. They arise for example as Kleisli categories of commutative monads on cartesian categories, and as such they provide a general framework for effectful computation. Recently proposed in the context of categorical probability, Markov categories are gs-monoidal categories where the monoidal unit is also terminal, and they arise for example as Kleisli categories of commutative affine monads, where affine means that the monad preserves the monoidal unit. The aim of this paper is to study a new condition on the gs-monoidal structure, resulting in the concept of weakly Markov categories, which is intermediate between gs-monoidal categories and Markov ones. In a weakly Markov category, the morphisms to the monoidal unit are not necessarily unique, but form a group. As we show, these categories exhibit a rich theory of conditional independence for morphisms, generalising the known theory for Markov categories. We also introduce the corresponding notion for commutative monads, which we call weakly affine, and for which we give two equivalent characterisations. The paper argues that these monads are relevant to the study of categorical probability. A case at hand is the monad of finite non-zero measures, which is weakly affine but not affine. Such structures allow to investigate probability without normalisation within an elegant categorical framework

    Implementation of guidelines about women with previous cesarean section through educational/motivational interventions in providers

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    Objective: The study reports the effect of a quality improvement project with an educational/motivational intervention, in northern Italy on the implementation of the trial of labor after Caesarean Section (CS). Method: A pre-post study design was used. Every birth center (23) of the Emilia-Romagna region was included. Gynecologists' opinion leaders were first trained about CS Italian recommendations. Barriers to implementation were discussed and shared. Educational/motivational interventions were implemented. Data of multipara with previous CS, with a single, cephalic pregnancy at term, were collected in 2 periods, before (2012-2014) and after (2017-2019) the intervention (2015-2016). The primary outcome was the rate of vaginal birth after CS (VBAC) and perinatal outcomes. Results: A total of 20,496 women were included. The VBAC rate increased from 18.1% to 23.1% after intervention (p<0.001). The likelihood of VBAC, adjusted for age ≥40, Caucasian, BMI ≥30, previous vaginal delivery, and labor induction, was increased by the intervention of 42% (OR=1.42, 95% CI 1.31-1.54). Neonatal well-being was improved by intervention, indeed neonates requiring resuscitation decreased from 2.1% to 1.6% (p=0.001). Conclusion: Educating and motivating gynecologists toward the trial of labor after CS is worth pursuing. Health quality improvement is demonstrated by increased VBAC even improving neonatal well-being

    Protective effects of melatonin in inflamed intestinal epithelium are associated with reduced NF-κB activation and changes in DNA methylation status

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    Melatonin is the main product of the pineal gland but is also released in the gastrointestinal tract (GIT). Production of melatonin at GIT is independent of the photoperiod and contributes almost completely to plasma melatonin concentration during daylight hours. The physiological role of melatonin at GIT is poorly characterized but recently anti-inflammatory effects have been reported. In this study, we evaluated the effect of Melatonin in intestinal epithelial cells (IEC) stimulated by Interleukin-1β. Our results clearly show that melatonin at micromolar concentrations inhibits the inflammatory response in IEC. The protective effect is expressed through a marked decrease in release and expression of inflammatory mediators, inhibition of DNA damage, and reduced activation of the NF-κB. Moreover, our results provide evidence that local inhibitor effect of Melatonin can involve an epigenetic mechanism also. In conclusion, our findings suggest that the intake of small amounts of melatonin, comparable with those found in pharmaceutical preparations used for sleep disorders, can also exert beneficial effects to the gastrointestinal physiology

    Healthcare Resources Use in Patients with Human Immunodeficiency Virus (HIV). Real-World Evidence From Six Italian Local Health Units

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    AIM: The aim of the study was to evaluate healthcare resource use and related costs for the management of people living with Human Immunodeficiency Virus (PLWHIV) with and without comorbidities, and to compare the burden of comorbidities in PLWHIV to the general population.METHODS: An observational retrospective analysis, based on administrative and laboratory databases from 6 Italian Local Health Units (LHUs) was performed. Individuals receiving either an HIV treatment [Antiretroviral therapy (ART) – ATC code: J05A)], or with an HIV positive laboratory test result between January 1st, 2014 and December 31st, 2014 were included. The date of first ART prescription or positive test of HIV was used as the Index Date (ID). Patients enrolled were followed-up for all time available from the ID (follow-up period) and their clinical characteristics were investigated from one year prior to the ID (characterization period). Comorbidities were measured by using the Charlson Comorbidity Index; findings were compared with those of a sample of the general population with the same age and sex distribution (OsMed 2015). Healthcare resource use and related cost was evaluated during the follow-up period.RESULTS: 1,214 patients were included, 837 were PLWHIV without any comorbidities and 377 were PLWHIV with at least one comorbidity. Mean prevalence of prescriptions for treatment of comorbidities was higher in the HIV-infected population than in the Italian general population. The annual healthcare cost of managing HIV patients with comorbidities, was significantly higher than that for patients without comorbidities (€ 10,615 vs. € 8,665, p < 0.001).CONCLUSIONS: Study results showed that 30% of PLWHIV had at least one comorbidity. The cost of managing PLWHIV who have comorbidities was significantly higher than that of managing PLWHIV without comorbidities. Our data confirm that care and treatment services should be adapted to address the specific needs of people living with both HIV and comorbidities

    Left Ventricular Function, Epicardial Adipose Tissue, and Carotid Intima-Media Thickness in Children and Adolescents With Vertical HIV Infection.

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    BACKGROUND: Life expectancy of HIV patients has increased considerably as a result of antiretroviral therapy (ART), and cardiovascular (CV) disease has emerged as an important late concern. People with HIV infection could have an impaired systolic function; however data on diastolic function and markers of CV risk, such as epicardial adipose tissue (EAT) and intima-media thickness (IMT), are lacking. Aim of this study is to evaluate left ventricular function, EAT, and IMT in children and adolescents with vertically acquired HIV infection. METHODS: We enrolled 29 subjects on ART (13, 45% men; median age of 13.0, and interquartile range 9-18), and 29 age-matched controls. All patients and controls underwent echocardiographic evaluation, with study of the systolic and diastolic function and measurement of the EAT, and a carotid ultrasound study for IMT measurement. RESULTS: Comparing HIV-infected patients to healthy controls, we found a statistically significant increase of EAT and IMT (mean ± SD) (EAT: 3.16 ± 1.05 vs 1.24 ± 0.61 mm; P < 0.0001. IMT: 0.77 ± 0.15 vs 0.51 ± 0.11 mm; P < 0.0001), and a significant reduction of ejection fraction, evaluated with the biplane Simpson method (mean ± SD) (58.5% ± 6.66% vs 66% ± 4.24%; P = 0.029). These results are not related with age, gender, degree of lipodystrophy, dyslipidemia, hyperinsulinism, and ART duration or the use of single antiretroviral classes. CONCLUSIONS: Vertically infected HIV children and adolescents show an increased thickness of EAT and IMT, expression of potentially increased CV risk. They also show an impaired systolic function

    The Role of Pathological Method and Clearance Definition for the Evaluation of Margin Status after Pancreatoduodenectomy for Periampullary Cancer. Results of a Multicenter Prospective Randomized Trial

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    Simple SummaryThere is no clear evidence on the most effective method of pathological analysis and clearance definition (0 vs. 1 mm) to define R1 resection after pancreatoduodenectomy (PD). However, several studies showed that the R1 resection is a poor prognostic factor in patients that have undergone PDs for periampullary cancers. In this randomized clinical trial, specimens were randomized with two pathological methods, the Leeds Pathology Protocol (LEEPP) or the conventional method adopted before the study. The 1 mm clearance is the most effective factor in determining R1 rate after PD but only when adopting the LEEP, the R1 resection represents a significant prognostic factor.Background: There is extreme heterogeneity in the available literature on the determination of R1 resection rate after pancreatoduodenectomy (PD); consequently, its prognostic role is still debated. The aims of this multicenter randomized study were to evaluate the effect of sampling and clearance definition in determining R1 rate after PD for periampullary cancer and to assess the prognostic role of R1 resection. Methods: PD specimens were randomized to Leeds Pathology Protocol (LEEPP) (group A) or the conventional method adopted before the study (group B). R1 rate was determined by adopting 0- and 1-mm clearance; the association between R1, local recurrence (LR) and overall survival (OS) was also evaluated. Results. One-hundred-sixty-eight PD specimens were included. With 0 mm clearance, R1 rate was 26.2% and 20.2% for groups A and B, respectively; with 1 mm, R1 rate was 60.7% and 57.1%, respectively (p &gt; 0.05). Only in group A was R1 found to be a significant prognostic factor: at 0 mm, median OS was 36 and 20 months for R0 and R1, respectively, while at 1 mm, median OS was not reached and 30 months. At multivariate analysis, R1 resection was found to be a significant prognostic factor independent of clearance definition only in the case of the adoption of LEEPP. Conclusions. The 1 mm clearance is the most effective factor in determining the R1 rate after PD. However, the pathological method is crucial to accurately evaluate its prognostic role: only R1 resections obtained with the adoption of LEEPP seem to significantly affect prognosis
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