Regularity bounds by minimal generators and Hilbert function

Let $\rho_C$ be the regularity of the Hilbert function of a projective curve $C$ in \mbox {P}^n_K over an algebraically closed field $K$ and $\beta_1, \ldots, \beta_{n-1}$ be degrees for which there exists a complete intersection of type ($\beta_1, \ldots, \beta_{n-1}$) containing properly $C$. Then the Castelnuovo-Mumford regularity of $C$ is bounded above by max $\{\rho_C +1, \beta 1 + \ldots + \beta_n-1 -(n-1)\}$ .We investigate the sharpness of the above bound, which is achieved by curves algebraically linked to ones having degenerate general hyperplane section

Projecting Changes in Tanzania Rainfall for the 21st century: Scenarios, Downscaling & Analysis

A Non-Homogeneous hidden Markov Model (NHMM) is developed using a 40-years record (1950-1990) of daily rainfall at eleven stations in Tanzania and re-analysis atmospheric fields of Temperature (T) at 1000 hPa, Geo Potential Height (GPH) at 1000 hPa, Meridional Winds (MW) and Zonal Winds (ZW) at 850 hPa, and Zonal Winds at the Equator(ZWE) from 10 to 1000 hPa. The NHMM is then used to predict future rainfall patterns under a global warming scenario (RCP8.5), using predictors from the CMCC-CMS simulations from 1950-2100. The model directly considers seasonality through changes in the driving variables thus addressing the question of how future changes in seasonality of precipitation can be modeled. The future downscaled simulations from NHMM, with predictors derived from the simulations of the CMCC-CMS CGM, in the worst conditions of global warming as simulated by RCP8.5 scenario, indicate that, Tanzania may be subjected to to a reduction of total annual rainfall; this reduction is concentrated in the wet seasons, OND, mainly as a consequence of decreasing of seasonal number of wet days. . Frequency and Intensity of extreme events don’t show any evident trend during the 21 century

RISCHIO, CRISI E INTERVENTO PUBBLICO NELL'AGRICOLTURA EUROPEA

Esiste un’ampia discussione tra le Istituzioni Europee (Commissione, Parlamento e Governi degli Stati Membri) sull’opportunità di istituire un quadro istituzionale di riferimento a livello europeo per la gestione del rischio e delle crisi in agricoltura. Allo scopo di analizzare la posizione assunta dalla Commissione Europea nel Marzo del 2004, l’articolo discute della possibilità di istituire un tale quadro comune di riferimento date le prospettive cui si trova di fronte la Politica Agricola Comune recentemente riformata. Nel far ciò, vengono passate in rassegna le misure esistenti nei vari Stati Membri e vengono valutati i punti di forza e di debolezza delle opzioni avanzate dalla Commissione. La conclusione è che, dati i vincoli esistenti sulla possibile espansione della spesa in agricoltura, l’istituzione di un programma comune basato sul pagamento di integrazioni di reddito o di sussidi a premi assicurativi è molto poco verosimile. Prospettive migliori sono quelle per un intervento basato sul sostegno di fondi mutualistici tra gli agricoltorie, più in generale, su sostegni indiretti al credito, alle assicurazioni e ai mercati finanziari, orientati al rendere tali strumenti più facilmente accessibili per gli agricoltor

Non-continuous Froude number scaling for the closure depth of a cylindrical cavity

A long, smooth cylinder is dragged through a water surface to create a cavity with an initially cylindrical shape. This surface void then collapses due to the hydrostatic pressure, leading to a rapid and axisymmetric pinch-off in a single point. Surprisingly, the depth at which this pinch-off takes place does not follow the expected Froude$^{1/3}$ power-law. Instead, it displays two distinct scaling regimes separated by discrete jumps, both in experiment and in numerical simulations (employing a boundary integral code). We quantitatively explain the above behavior as a capillary waves effect. These waves are created when the top of the cylinder passes the water surface. Our work thus gives further evidence for the non-universality of the void collapse

Computational and experimental investigation of mixing in microchannels

This paper was presented at the 2nd Micro and Nano Flows Conference (MNF2009), which was held at Brunel University, West London, UK. The conference was organised by Brunel University and supported by the Institution of Mechanical Engineers, IPEM, the Italian Union of Thermofluid dynamics, the Process Intensification Network, HEXAG - the Heat Exchange Action Group and the Institute of Mathematics and its Applications.Mixing is a key process for the successful of all chemical or biochemical reactions, so effective micromixers represent essential components for micro total analysis systems (μTAS) or lab-on-a-chip. In the present study a combined computational and experimental approach was adopted to evaluate how the efficiency of a Y-mixer can be enhanced by modifying its downstream geometry. Three different geometries were studied and compared: Y-straight channel, Y-sine channel and Y-wrinkled wall channel. For each of them the influence of perfusing flow rates and channel cross section aspect ratio was investigated. Physical prototypes were built using a simple technique based on a xerographic process, and their mixing performance was experimentally evaluated. Computational models of the designed micromixers were generated: the Navier-Stokes equations for an incompressible Newtonian fluid and the advection-diffusion equation were solved with an uncoupled approach by means of the finite volume method. The computational and experimental results were critically compared, revealing Y-wrinkled wall mixer as the best performer among those considered and suggesting criteria of possible improvements and optimization

Mechanical Performances of Weathered Coal Fly Ash Based Geopolymer Bricks

In this paper weathered coal fly ash has been used in polycondensation processes aimed at the production of geopolymer-based low temperature ceramic bricks. The ash has been employed both "as received" and after drying, showing favorable reactivity in any case. Different curing conditions with a variable period at 60 °C have been tested. Samples obtained have been characterized by measuring Unconfined Compressive Strength (UCS) and by SEM observations. Good strength values have been obtained with the systems tested. Furthermore, it has been found that mechanical performance increases as the time during which samples are kept at 60 °C increases

A stacked ensemble learning and non-homogeneous hidden Markov model for daily precipitation downscaling and projection

Global circulation models (GCMs) are routinely used to project future climate conditions worldwide, such as temperature and precipitation. However, inputs with a finer resolution are required to drive impact-related models at local scales. The nonhomogeneous hidden Markov model (NHMM) is a widely used algorithm for the precipitation statistical downscaling for GCMs. To improve the accuracy of the traditional NHMM in reproducing spatiotemporal precipitation features of specific geographic sites, especially extreme precipitation, we developed a new precipitation downscaling framework. This hierarchical model includes two levels: (1) establishing an ensemble learning model to predict the occurrence probabilities for different levels of daily precipitation aggregated at multiple sites and (2) constructing a NHMM downscaling scheme of daily amount at the scale of a single rain gauge using the outputs of ensemble learning model as predictors. As the results obtained for the case study in the central-eastern China (CEC), show that our downscaling model is highly efficient and performs better than the NHMM in simulating precipitation variability and extreme precipitation. Finally, our projections indicate that CEC may experience increased precipitation in the future. Compared with around 26 years (1990–2015), the extreme precipitation frequency and amount would significantly increase by 21.9%– 48.1% and 12.3%–38.3%, respectively, by the late century (2075–2100) under the Shared Socioeconomic Pathway 585 climate scenario

Hazard Assessment from Storm Tides and Rainfall on a Tidal River Estuary

Here, we report on methods and results for a model-based flood hazard assessment we have conducted for the Hudson River from New York City to Troy/Albany at the head of tide. Our recent work showed that neglecting freshwater flows leads to underestimation of peak water levels at up-river sites and neglecting stratification (typical with two-dimensional modeling) leads to underestimation all along the Hudson. As a result, we use a three-dimensional hydrodynamic model and merge streamflows and storm tides from tropical and extratropical cyclones (TCs, ETCs), as well as wet extratropical cyclone (WETC) floods (e.g. freshets, rain-on-snow events). We validate the modeled flood levels and quantify error with comparisons to 76 historical events. A Bayesian statistical method is developed for tropical cyclone streamflows using historical data and consisting in the evaluation of (1) the peak discharge and its pdf as a function of TC characteristics, and (2) the temporal trend of the hydrograph as a function of temporal evolution of the cyclone track, its intensity and the response characteristics of the specific basin. A k-nearest-neighbors method is employed to determine the hydrograph shape. Out of sample validation tests demonstrate the effectiveness of the method. Thus, the combined effects of storm surge and runoff produced by tropical cyclones hitting the New York area can be included in flood hazard assessment. Results for the upper Hudson (Albany) suggest a dominance of WETCs, for the lower Hudson (at New York Harbor) a case where ETCs are dominant for shorter return periods and TCs are more important for longer return periods (over 150 years), and for the middle-Hudson (Poughkeepsie) a mix of all three flood events types is important. However, a possible low-bias for TC flood levels is inferred from a lower importance in the assessment results, versus historical event top-20 lists, and this will be further evaluated as these preliminary methods and results are finalized. Future funded work will quantify the influences of sea level rise and flood adaptation plans (e.g. surge barriers). It would also be valuable to examine how streamflows from tropical cyclones and wet cool-season storms will change, as this factor will dominate at upriver locations

Metastatic lung cancer presenting as thoracic empyema: A Case report

Increased cancer risk in patients with inflammatory and infectious diseases has been reported in many studies and lung cancer\u2010associated empyema in <0.3% patients. We present a patient with empyema in whom the final diagnosis was metastatic lung adenocarcinoma. Purulent pleural fluid obtained by drainage or thoracentesis must always been examined because the association of malignant tumors and empyema should be taken into consideration