INTRUDER: a device to improve hull performances

The intruder is a device that has been used for a long time now on big fast monohulls like "Acquastrada". It consists of a small vertical thin plate positioned under the transom of a planing or semi-planing hull, jutting out just a few millimetres. It is able to improve hull performances assuring a smaller drag thus a higher speed for the same installed power. For this reason, for its working and installation simplicity, as well as for its low cost, the intruder is becoming increasing popular even with small working and sports crafts. In order to improve the knowledge about the hydrodynamic effects caused by this device, some tests have been performed at INSEAN using three planing and semi-planing models. As the results of tests show, the intruder changes significantly the dynamic trim of the hull and it raises the stern. These effects can reduce the wave pattern and thus the drag. The improvements are larger in the pre-planing phase (1<Fn&#61649;<2.5) where drag reductions - of more than 20% - have been measured.L\u27intruder ? un dispositivo da tempo utilizzato in campo navale sui grandi monoscafi veloci tipo Acquastrada: non ha una definizione univoca e pu? essere chiamato anche interceptor, tegolo poppiero, o altro. ? costituito da una piccola lamina verticale posta in corrispondenza dello specchio di poppa sporgente alcuni millimetri dal fondo di una carena planante o semiplanante. Esso pu? essere utilizzato in alternativa ai flap come stabilizzatore e/o correttore d\u27assetto, ma ? anche in grado di migliorare le prestazioni della carena, garantendo una minor resistenza all\u27avanzamento e, di conseguenza, una maggior velocit? a parit? di potenza installata. Per questo motivo, per la sua estrema semplicit? di funzionamento e di installazione anche su scafi esistenti, nonch? per la sua economicit?, l\u27intruder, sia di tipo commerciale a sporgenza variabile comandata a distanza, sia di tipo fisso, si va diffondendo anche su imbarcazioni veloci di piccole dimensioni sia da lavoro che da diporto. Sul funzionamento dell\u27intruder, o meglio su una valutazione quantitativa degli effetti che esso produce, si hanno ancora poche informazioni, per cui non ? possibile formulare delle regole precise di utilizzo. Proprio al fine di fornire una pi? efficace valutazione degli effetti idrodinamici generati da questo dispositivo, sono state eseguite presso la Vasca Navale di Roma (INSEAN), alcuni test sperimentali comparativi con e senza intruder su tre modelli di imbarcazioni plananti e semiplananti. Su uno dei tre modelli sono stati eseguiti ulteriori test per comparare l\u27efficacia dell\u27intruder a quella di flap di tipo e dimensioni commerciali. Alla luce dei test eseguiti l\u27installazione di questo dispositivo modifica significativamente l\u27assetto dinamico assunto dall\u27imbarcazione e genera una sopraelevazione della poppa. Tali modifiche possono produrre una sensibile riduzione della formazione ondosa e quindi della resistenza della carena. Gli effetti positivi sono pi? consistenti in fase di preplanata (1<Fn&#61649;<2.5), dove sperimentalmente sono state riscontrate riduzioni di resistenza che hanno superato anche il 20%

Dipendenza della ripetibilit? dei risulati dei test di elica isolata dal numero di Reynolds

According to current European regulations for calculating measurement uncertainty, besides computation of sensibility coefficients by, for example, OFAT tests, we have to evaluate the own repeatability of measurement device and technique, in order to estimate the influence of not controlled parameters. The aim of the present work is to show that repeatability of open water test results depends on the performed Reynolds number. A large set of tests performed on four screws models, with different shapes, diameters and blades numbers, has shown that, the coefficients of variation of torque and trust measurements, as well as standard deviation of hydrodynamic coefficients KQ and KT, decrease if Reynolds number increases, with a trend well fitted by a rational function like kx-?. The obtained results show that, if Reynolds number is about 750.000, standard deviations of torque and trust are about 0.5% of carried out measures, as well those of KQ and KT that are about 0.001, that is, in the worst case, the 0.5% of the mean value. In addition to what already shown by ITTC (International Towing Tank Conference) procedures, this conclusion provides useful information about the minimum Reynolds number to perform open water tests limiting the uncertainty intervals.Secondo quanto previsto dall\u27attuale normativa europea per la determinazione dell\u27incertezza di misura [1], oltre ad individuare i coefficienti di sensibilit? mediante ad esempio prove OFAT (one factor a time), ? necessario stimare la ripetitivit? intrinseca del sistema di misura cos? da valutare l\u27influenza dei parametri non sotto controllo. Obiettivo del presente Rapporto Tecnico ? mostrare come la ripetitivit? dei risultati ottenuti in una prova di elica isolata dipenda dal numero di Reynolds a cui ? stata eseguita. In particolare l\u27esecuzione di un cospicuo numero di misure (627 punti sperimentali) su 4 eliche con caratteristiche geometriche diverse, ha mostrato che, al crescere del numero di Reynolds, il coefficiente di variazione relativo alle misure di coppia e di spinta, nonch? la deviazione standard dei coefficienti idrodinamici KQ e KT, diminuiscono con andamenti generalmente ben approssimabili con funzioni razionali del tipo kx-?. I risultati ottenuti mostrano che, quando il numero di Reynolds raggiunge i 750.000, le deviazioni standard delle misure di coppia e di spinta scendono intorno allo 0,5% delle misure effettuate, e quelle di KT e KQ scendono intorno a 0.001, che, nel peggiore dei casi analizzato, ? anch\u27esso circa lo 0,5% del valore medio. Tale risultato fornisce utili indicazioni per l\u27individuazione del numero minimo di Reynolds a cui ? opportuno effettuare prove di elica isolata all\u27Insean

Bianchi I model as a prototype for a cyclical Universe

We analyze the dynamics of the Bianchi I model in the presence of stiff matter, an ultrarelativistic component and a small negative cosmological constant. We quantize this model in the framework of the polymer quantum mechanics, in order to introduce cut-off features in the minisuperspace dynamics. We then apply to the polymer Wheeler-DeWitt equation, emerging from the Dirac constraint, an adiabatic approximation a la Vilenkin, which treats the Universe volume as a quasi-classical variable, becoming de facto the dynamical clock for the pure quantum degrees of freedom, here identified in the Universe anisotropies. The main issue of the present analysis consists of determining a cyclical evolution for the Bianchi I model, oscillating between the Big-Bounce induced by the cut-off physics and the turning point due to the small cosmological constant. Furthermore, the mean value of the Universe anisotropy variables remains finite during the whole evolution, including the phase across the Big-Bounce. Such a feature, according to a suitable choice of the initial conditions makes the present cosmological paradigm, a viable scenario for the description of a possible primordial and late phases of the actual Universe.Comment: 12 pages, 6 figure

Reply to Berk et al. Comment on "Moriconi et al. Very-low-calorie ketogenic diet as a safe and valuable tool for long-term glycemic management in patients with obesity and type 2 diabetes. Nutrients 2021, 13, 758"

We thank the authors of the comment [...]

Very-low-calorie ketogenic diet as a safe and valuable tool for long-term glycemic management in patients with obesity and type 2 diabetes

Obesity-related type 2 diabetes represents one of the most difficult challenges for the healthcare system. This retrospective study aims to determine the efficacy, safety and durability of a very-low-calorie ketogenic diet (VLCKD), compared to a standard low-calorie diet (LCD) on weight-loss, glycemic management, eating behavior and quality of life in patients with type 2 diabetes (T2DM) and obesity. Thirty patients with obesity and T2DM, aged between 35 and 75 years, who met the inclusion criteria and accepted to adhere to a VLCKD or a LCD nutritional program, were consecutively selected from our electronic database. Fifteen patients followed a structured VLCKD protocol, fifteen followed a classical LCD. At the beginning of the nutritional protocol, all patients were asked to stop any antidiabetic medications, with the exception of metformin. Data were collected at baseline and after 3 (T1) and 12 (T2) months. At T1 and T2, BMI was significantly reduced in the VLCKD group (p &lt; 0.001), whereas it remained substantially unchanged in the LCD group. HbA1c was significantly reduced in the VLCKD group (p = 0.002), whereas a slight, although not significant, decrease was observed in the LCD group. Quality of life and eating behavior scores were improved in the VLCKD group, whereas no significant changes were reported in the LCD group, both at T1 and T2. At the end of the study, in the VLCKD group 26.6% of patients had stopped all antidiabetic medications, and 73.3% were taking only metformin, whereas 46.6% of LCD patients had to increase antidiabetic medications. The study confirms a valuable therapeutic effect of VLCKD in the long-term management of obesity and T2DM and its potential contribution to remission of the disease

Repeatability estimation of torque and thrust results in open water tests as a function of the Reynolds number

According to current European regulations for calculating measurement uncertainty, besides the computation of sensibility coefficients by, for example, OFAT tests, it\u27s useful to evaluate the own repeatability of measurement device and technique, in order to estimate the influence of the not controlled parameters. The aim of the present work is to show that repeatability of open water test results depends strongly on the performed Reynolds number. A large set of tests carried out on four screws models, with different shapes, diameters and blades numbers (for a total of 627 experimental data), has shown that the coefficients of variation of torque and thrust measurements, as well as standard deviation of hydrodynamic coefficients KQ and KT, decrease if Reynolds number increases, with a trend well fitted by a rational function like kx-a. Results show also that, if Reynolds number is about 750.000, standard deviations of torque and thrust are about 0.5% of the obtained measures, as well as those of KQ and KT. In addition to what already shown by ITTC (International Towing Tank Conference) Procedures, this conclusion provides useful information about the minimum Reynolds number at which to perform open water tests in order to limit the uncertainty intervals

Concentración Gravitacional de una Muestra de Baritina

Fil: Sánchez, Laura Miriam. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales. Instituto de Tecnología Minera; Argentina.Fil: Iñiguez, Verónica Andrea. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales. Instituto de Tecnología minera; Argentina.Fil: Moriconi, Micaela. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales. Instituto de Tecnología Minera; Argentina.En la Dirección de Ensayos y Procesos se realizó el estudio de concentración de una muestra de baritina del yacimiento Achalay ubicado en el Cordón del Cuchillo Curá, en el Departamento Picunches de la Provincia del Neuquén. La muestra fue suministrada por la Lic. Belén Bollini de la Universidad de Comahue quién utilizó nuestro estudio de concentración en mesa wilfley como patrón comparativo con su proceso realizado en paralelo en la Universidad mencionada. El trabajo final concluyó en la Tesina de Grado de la actual Licenciada en Tecnología Minera Belén Bollini

Percepciones de los docentes con respecto al rendimiento académico durante la pandemia de COVID-19

El presente trabajo se realizó en el marco de la cátedra de Bioquímica y Biología Molecular de la Facultad de Ciencias Médicas de la Universidad Nacional de La Plata (UNLP) y tuvo como objetivo analizar, desde el punto de vista docente, los motivos subyacentes a la disminución progresiva en el rendimiento académico de los alumnos en los años de pandemia. Bioquímica y Biología Molecular es parte del ciclo básico de la carrera de Medicina y la comprensión e integración de sus contenidos contribuye a su formación profesional y es clave para interpretar los saberes de materias posteriores. Para realizar el trabajo se analizaron los datos de rendimiento académico durante la cursada de las cohortes de alumnos 2019, 2020 y 2021, así como también algunos puntos de entrevistas semiestructuradas realizadas a estudiantes y docentes de la cátedra, que están relacionadas con la temática a desarrollar. El análisis de los resultados nos permitió encontrar puntos de coincidencia entre la mirada de los docentes y los estudiantes acerca de la problemática en cuestión, así como también temas de reflexión que aportarán a mejorar la tríada enseñanza-aprendizaje-evaluación entre todos los participantes involucrados.Especialización en Docencia UniversitariaFacultad de Ciencias Médica

Puesta en valor de la extensión universitaria: curricularización para una integración real con investigación y docencia

This work is presented as the result of a complex, continuum and long reflexive process about our teaching practices along different workshops, meetings and collaborative exchanges in our teaching formation journey. The text includes our revisions about educational fragmentation and the importance of an integral, social and collectively constructed professional formation. We consider the importance of the articulation between teaching, research and extension practices for the social, political and historically situated teaching and learning processes, which promote a professional profile more committed to political-social problems, and we place the University as a fundamental institutional actor in the permanent exchange with the community. We also include concrete proposals for curricularisation of extension as an innovative pedagogical strategy to implement in university teaching practices in response to the problems addressed.Este trabajo se origina en respuesta a un proceso reflexivo complejo y continuo de nuestras prácticas docentes a lo largo de distintos encuentros, talleres e intercambios de la especialización en docencia universitaria de la Universidad Nacional de La Plata. A lo largo del texto plasmamos nuestras revisiones sobre la fragmentación en la educación y la necesidad de una formación integral, social y colectivamente construida. Consideramos la importancia de la articulación entre docencia, investigación y extensión para los procesos de enseñanza y aprendizaje social, política e históricamente situados, que promuevan un perfil profesional y ciudadano más comprometido con las problemáticas político-sociales, y situamos a la Universidad como actor institucional fundamental en el intercambio permanente con la comunidad. Incluimos también propuestas concretas de curricularización de la extensión como estrategia pedagógica innovadora para implementar en las prácticas docentes universitarias en respuesta a las problematizaciones abordadas

Laser Excisional Treatment for Vaginal Intraepithelial Neoplasia to Exclude Invasion

Objective: We undertook a retrospective analysis of the incidence of complications of carbon dioxide (CO2) laser excision for high-grade vaginal intraepithelial neoplasia (HG-VaIN).Materials and Methods: Retrospective large case series on 128 CO2 laser excisions for HG-VaIN in 106 women treated at the Department of Gynecologic Oncology, Oncologic Referral Center, Aviano, Italy. These procedures were performed under local anesthesiawith a 20-Wcontinuous laser beam focused to a 0.2-mm spot size. Complications were defined as "minor" when limited to vagina, and "major" when surrounding organs were injured or the vaginal vault was opened. To identify possible factors associated with surgical complications, we performed a univariate analysis with the t test for continuous variables and x(2) or Fisher exact test for qualitative variables as appropriate.Results: The overall rate of complication was 7.8% (10/128); nine of themwere vaginal bleeding, and only one (0.8%) was amajor complication with vaginal vault perforation. A greater number of previous destructive treatments and of two or more previous laser vaginal excisional treatments was present in patients with complications compared with ones without complications (10% vs 3.9 %, p = .92, and 30% vs 15.2%, p = .44, respectively), although these differences were not statistically significant. A total of 10.5% (6/57) of occult vaginal cancer was detected in women with initial diagnosis of VaIN3 (HG-VaIN) on biopsy.Conclusions: Carbon dioxide laser excision for HG-VaIN seems to be a safe approach with low rate of complications, probably because of the better accuracy achieved by CO2 laser resections, and permits diagnosis of occult invasive disease