design of passive ring resonators to be used for sensing applications

In this paper we report on the effects of two optical beams counterpropagating in a passive ring resonator that is the building block of a lot of sensing applications. By using the transfer matrix method in combination with the coupled mode theory, the analytical expressions of the power transfer functions for drop and through port configurations are derived in both cases of single beam and double beams inside the ring. The implemented model has shown some improvements in the resonator performance, such as the increase of the transmission power and the reduction of the linewidth, when the interaction between the two beams is considered, with respect to the single beam ring resonator configuration

Rainfall effects on nitrogen availability in soils with contrastingdegradation in north-eastern Chubut

En los ecosistemas áridos, la precipitación anual es considerada un factor determinante de su funcionamiento. Los cambios en su estacionalidad y/o en la frecuencia en que ocurren eventos extremos de lluvia podrían tener un importante impacto ecológico y biogeoquímico, dependiendo del estado de conservación del suelo. El objetivo de este trabajo fue evaluar la influencia de lluvias estacionales de gran magnitud (riegos de 40 mm) sobre la disponibilidad de N (amonio y nitrato) en suelos del NE de Chubut con distintos niveles de erosión. Se eligieron dos comunidades vegetales que representan dos situaciones de erosión de suelos: una estepa herbácea con arbustos con suelos no erosionados (EHA) y una estepa arbustiva erosionada (EA). El experimento de un año de duración tuvo un diseño factorial de tres factores: estación de riego (invernal y primaveral), dos niveles de riego (con y sin riego) y dos comunidades (EHA y EA). Para los tratamientos de riego, el agua se agregó en un único momento durante el invierno y/o la primavera, simulando un evento de precipitación grande (40 mm). Se colectaron muestras de suelo superficial (0-5 cm) y sub-superficial (5-15 cm) de las parcelas en 4 fechas: inmediatamente antes del riego, a los 3, 6 y 14 días luego de su aplicación. No se encontraron diferencias en el N total entre los suelos de las comunidades. El riego invernal no tuvo efecto en los contenidos de amonio y nitrato de los suelos de la EHA ni de la EA. En cambio, en primavera se encontró mayor contenido de nitrato en la capa superficial del suelo de la EHA. Nuestros resultados sugieren que la falta de respuesta en el contenido de nitrato en los suelos erosionados (EA) luego de un evento de lluvia grande sería consecuencia de la menor infiltración y del menor aumento del contenido hídrico en la EA respecto a la EHA.Annual precipitation exerts a key control on the functioning of arid ecosystems. However, changes in seasonality and/or in the frequency of extreme precipitation events could have great ecological and biogeochemical impacts. Moreover, these impacts would be in relation to the degree of soil conservation. Our objective was to examine the effect of seasonal rainfall events on N availability (nitrate and ammonium) in soils with contrasting degradation in northeastern Chubut. Two steppes with contrasting soil erosion levels were chosen: herbaceous steppe with shrubs (EHA) and degraded shrub steppe (EA). We performed a one-year experiment with 3 factors: rainfall seasonality simulation (winter or spring irrigation), irrigation (with and without), and two plant communities (EHA and EA). Plots were watered in a single event during winter and/or spring, simulating a great rainfall event of 40 mm. Soil samples were taken immediately before watering and 3, 6, and 14 days after watering. Soil samples were separated into superficial (0-5 cm) and sub-superficial (5-15 cm) depths. Total N contents were similar between soils of the two communities. In winter, there was no effect of watering on the contents of ammonium and nitrate, neither in EHA nor EA. In spring, there were higher nitrate contents at the superficial layer on the watered soils in EHA. Our results suggest that nitrates in eroded soils of EA did not respond to watering as a consequence of lower infiltration rates and subsequently lower increases in soil water content in that community in comparison with EHA.Fil: Campanella, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Rostagno, Cesar Mario. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina. Universidad Nacional de la Patagonia; ArgentinaFil: Videla, Lina Sonia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; ArgentinaFil: Bisigato, Alejandro Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentina. Universidad Nacional de la Patagonia; Argentin

Phononic and photonic band gap structures: modelling and applications

AbstractPhotonic crystals (PhCs) are artificial materials with a permittivity which is a periodic function of the position, with a period comparable to the wavelength of light. The most interesting characteristic of such materials is the presence of photonic band gaps (PBGs). PhCs have very interesting properties of light confinement and localization together with the strong reduction of the device size, orders of magnitude less than the conventional photonic devices, allowing a potential very high scale of integration. These structures possess unique characteristics enabling to operate as optical waveguides, high Q resonators, selective filters, lens or superprism. The ability to mould and guide light leads naturally to novel applications in several fields.Band gap formation in periodic structures also pertains to elastic wave propagation. Composite materials with elastic coefficients which are periodic functions of the position are named phononic crystals. They have properties similar to those of photonic crystals and corresponding applications too. By properly choosing the parameters one may obtain phononic crystals (PhnCs) with specific frequency gaps. An elastic wave, whose frequency lies within an absolute gap of a phononic crystal, will be completely reflected by it. This property allows realizing non-absorbing mirrors of elastic waves and vibration-free cavities which might be useful in high-precision mechanical systems operating in a given frequency range. Moreover, one can use elastic waves to study phenomena such as those associated with disorder, in more or less the same manner as with electromagnetic waves.The authors present in this paper an introductory survey of the basic concepts of these new technologies with particular emphasis on their main applications, together with a description of some modelling approaches

Automated Quality Assessment of Space-Continuous Models for Pedestrian Dynamics

In this work we propose a methodology for assessment of pedestrian models continuous in space. With respect to the Kolmogorov-Smirnov distance between two data clouds, representing for instance simulated and the corresponding empirical data, we calculate an evaluation factor between zero and one. Based on the value of the herein developed factor, we make a statement about the goodness of the model under evaluation. Moreover this process can be repeated in an automatic way in order to maximize the above mentioned factor and hence determine the optimal set of model parameters.Comment: 8 pages, 3 figures, accepted at the Proceedings of Traffic and Granular Flow '1

Infected pancreatic necrosis: outcomes and clinical predictors of mortality. A post hoc analysis of the MANCTRA-1 international study

: The identification of high-risk patients in the early stages of infected pancreatic necrosis (IPN) is critical, because it could help the clinicians to adopt more effective management strategies. We conducted a post hoc analysis of the MANCTRA-1 international study to assess the association between clinical risk factors and mortality among adult patients with IPN. Univariable and multivariable logistic regression models were used to identify prognostic factors of mortality. We identified 247 consecutive patients with IPN hospitalised between January 2019 and December 2020. History of uncontrolled arterial hypertension (p = 0.032; 95% CI 1.135-15.882; aOR 4.245), qSOFA (p = 0.005; 95% CI 1.359-5.879; aOR 2.828), renal failure (p = 0.022; 95% CI 1.138-5.442; aOR 2.489), and haemodynamic failure (p = 0.018; 95% CI 1.184-5.978; aOR 2.661), were identified as independent predictors of mortality in IPN patients. Cholangitis (p = 0.003; 95% CI 1.598-9.930; aOR 3.983), abdominal compartment syndrome (p = 0.032; 95% CI 1.090-6.967; aOR 2.735), and gastrointestinal/intra-abdominal bleeding (p = 0.009; 95% CI 1.286-5.712; aOR 2.710) were independently associated with the risk of mortality. Upfront open surgical necrosectomy was strongly associated with the risk of mortality (p < 0.001; 95% CI 1.912-7.442; aOR 3.772), whereas endoscopic drainage of pancreatic necrosis (p = 0.018; 95% CI 0.138-0.834; aOR 0.339) and enteral nutrition (p = 0.003; 95% CI 0.143-0.716; aOR 0.320) were found as protective factors. Organ failure, acute cholangitis, and upfront open surgical necrosectomy were the most significant predictors of mortality. Our study confirmed that, even in a subgroup of particularly ill patients such as those with IPN, upfront open surgery should be avoided as much as possible. Study protocol registered in ClinicalTrials.Gov (I.D. Number NCT04747990)

Home-based palliative approach for people with severe multiple sclerosis and their carers: Study protocol for a randomized controlled trial

Background: Preliminary evidence suggests that palliative care may be useful for people with severe multiple sclerosis (MS). The aim of this study is to determine the effectiveness of a home-based palliative approach (HPA) for people with severe MS and their carers. Methods/design: This is a single-blind randomized controlled trial with a nested qualitative study. Seventy-five severe MS-carer dyads are being randomized (at three centers, one in each area of Italy) to HPA or usual care (UC) in a 2:1 ratio. Each center has a specially trained team consisting of four professionals (physician, nurse, psychologist, social worker). The team makes a comprehensive assessment of the needs of the dyads. HPA content is then agreed on, discussed with the patient's caring physician, and delivered over six months. The intervention is not intended to replace existing services. At later visits, the team checks the HPA delivery and reviews/modifies it as necessary. Discussion: The results of our study will show whether the HPA is feasible and beneficial to people with severe MS and their carers living in the three Italian geographic areas. The nested qualitative study will add to the understanding of the strengths and limitations of the intervention

Economia antropocentrica. La necessaria centralità dell'uomo per lo sviluppo economico

La crisi che ha investito i mercati finanziari, propagandosi anche all’economia reale, evidenzia la necessità di rivedere alcuni concetti alla base della relazione tra economia, finanza e sviluppo. L’auspicato cambiamento non può essere perseguito solo con l’introduzione di nuove norme, ma deve essere raggiunto agendo sulla formazione dell’uomo e instillando nella società un nuovo concetto di benessere più coincidente con la felicità. Se si parte da questa prospettiva, l’attenzione dell’economia si sposta dal capitale all’uomo, ai valori che egli incarna e alle conseguenti azioni che compie per la realizzazione di sé. In tal senso si intende l’espressione “economia antropocentrica” che costituisce il titolo di questo libro. Lo spostamento della funzione di utilità dall’accrescimento del capitale all’incremento del benessere dell’uomo (antropocentrismo), implica un recupero delle passate radici delle scienze economiche che ponevano al centro degli interessi il soddisfacimento dei bisogni umani attraverso un utilizzo efficiente delle limitate risorse