Characteristics and organization of precipitating features during NAME 2004 and their relationship to environmental conditions

2008 Fall.The focus of this study is to examine the characteristics of convective precipitating features (PFs) during the 2004 North American Monsoon Experiment (NAME) and their precursor environmental conditions. The goal is to gain a better insight into the predictability and variability of warm season convective processes in the southern portion of the North American Monsoon core region. The organization and characteristics of PFs are evaluated using composite radar reflectivity images over the southern portion of the Gulf of California. The environmental conditions are assessed using satellite images and a plethora of atmospheric observational analysis maps, such as winds at multiple levels, upper-level divergence, vorticity, vertical air motion, moisture and vertical cross-sections. Our study reveals that most PFs occurred during the afternoon and evening over land, especially near the foothills of the Sierra Madre Occidental. The vast majority of the precipitating features (~95%) were small, isolated, unorganized, short-lived convective cells. Mesoscale convective systems (MCSs) made up only 5% of the PF population. Nonetheless, these large, long-lived, precipitating features were responsible for 72% of the total precipitation within the radar composite region. An analysis of the number and rainfall produced by these MCSs revealed that they were not constant from day to day, but rather, varied significantly throughout NAME. We found that MCSs were more frequent when the atmosphere is thermodynamically unstable and the wind shear or large-scale dynamics favors the development of organized convection. Lastly, we examined the synoptic conditions associated with episodes of above average MCS rainfall in the southern portion of the NAME core region. Tropical waves were found to be an essential source of moisture and instability in the region. We also found that transient upper-level inverted troughs interact with the upper-level anticyclone to produce a "North American Monsoon Jet Streak" that created favorable dynamical uplift and wind shear conditions for MCS development

Optimization of a p-persistent Network Diversity Multiple Access Protocol for a SC-FDE System

This paper presents a Medium Access Control (MAC) protocol solution designed to properly handle collisions when in the presence of a multi-packet detection receiver for Single-Carrier (SC) modulations with Frequency-Domain Equalization (FDE). It is considered an iterative frequency-domain receiver that jointly performs equalization, multi-packet separation and channel decoding operations, for up to Qmax mobile terminals transmitting in one slot. In this work, it is proposed and evaluated a p-persistent Network Diversity Multiple Access (NDMA) random MAC protocol designed to cope with a total number of mobile terminals J, for a maximum decoding capability of Qmax simultaneous packets. An accurate analytical model is presented to optimize two different scenarios: in the first one, a saturated network is considered and it is determined the packet transmission probability that maximizes the uplink throughput; the second represents a non-saturated network and the goal is to compute the optimal transmission probability associated to each mobile terminal that minimizes the packet transmission delay. In the end, analytical results obtained through physical and MAC layer simulations are discussed

How to break access control in a controlled manner

The Electronic Medical Record (EMR) integrates heterogeneous information within a Healthcare Institution stressing the need for security and access control. The Biostatistics and Medical Informatics Department from Porto Faculty of Medicine has recently implemented a Virtual EMR (VEMR) in order to integrate patient information and clinical reports within a university hospital. With more than 500 medical doctors using the system on a daily basis, an access control policy and model were implemented. However, the healthcare environment has unanticipated situations (i.e. emergency situations) where access to information is essential. Most traditional policies do not allow for overriding. A policy that allows for Break-The-Glass (BTG) was implemented in order to override access control whilst providing for non-repudiation mechanisms for its usage. The policy was easily integrated within the model confirming its modularity and the fact that user intervention in defining security procedures is crucial to its successful implementation and use

Photon-number-resolving segmented avalanche-photodiode detectors

We investigate the feasibility and performance of photon-number-resolved photodetection employing avalanche photodiodes (APDs) with low dark counts. The main idea is to split n photons over m modes such that every mode has no more than one photon, which is detected alongside propagation by an APD. We characterize performance by evaluating the purities of positive-operator-valued measurements (POVMs), in terms of APD number and photon loss.Comment: 5 pages, 7 figures, submitted for publicatio

On stochastic aspects of impact modeling of the innovation incentive system and business internationalization: evidence from Portuguese SMEs

Multivariate normal distribution is base for many statistical techniques, including ordinary least square inference. Here we show that in order to make research on Internationalization of Companies, more flexible approach is needed, namely partial least squares (PLS). It is a nonparametric technique, used in Structural Equation Modeling (SEM), which makes no distributional assumptions and also may be applied with small sample sizes. In this study we discuss on regularity conditions for PLS from the perspective of semi-continuous covariance which fills the gap in the current studies. The stochastic aspects, especially those related to usage of PLS-SEM, can be well integrated to the topologically grounded regression, where jumps in the covariances can occur. The purpose of the research is to analyze and understand the impact of the Incentive System (IS) for Innovation, within the scope of the National Strategic Reference Framework (QREN) 2014-2020, on the Internationalization of Portuguese Small and Medium Enterprises (SMEs). We study stochastic aspects of theoretical model which aggregates the variables Product Innovation, Marketing Innovation, Organizational Innovation and Working Conditions as determinants of Internationalization of Companies. Data were collected based on a quantitative methodology, through a self-completion questionnaire using the Likert psychometric scale, which registered 120 participants. Organizational Innovation (exogenous latent construct) and Product Innovation have shown a statistically significant indirect effect on the Internationalization of Companies (endogenous latent construct) through Marketing Innovation. The latter has a direct effect on the Internationalization (target construct). However, Working Conditions has the greatest impact on Internationalization, meaning that measures such as increasing wages, decreasing the use of temporary work and precarious work conversion into labor effective relations have a very relevant direct effect on the Internationalization of Portuguese SMEs.FCT - Fundação para a Ciência e a Tecnologia, I.P., under the scope of the projects UIDB/00297/2020 and UIDP/00297/2020 (Center for Mathematics and Applications)

Fire effects on biochemical properties of a semiarid pine forest topsoil at cm-scale

Forest fires can greatly affect soil properties and processes. In the study of the fire effects on soil, the soil thickness affected by heat depends on the characteristics of the fire and soil itself, but also on the attribute to be measured. The objective of this work is to know to what thickness (up to 1, 2 or 3 cm) various sensitive soil properties are immediately affected by a controlled burning. To achieve this aim, unaltered fresh topsoil (mollic horizon) of a fire-prone Aleppo pine forest in the semiarid Ebro Valley (NE-Spain) were sampled and, without destroying their original structure, burned from the surface in an outdoor combustion tunnel in triplicate. Biological properties are measured, including basal and normalized soil respiration (bSR and nSR), β-D-glucosidase (GLUase) and phosphomonoestarase (PHOase) activities, and related parameters, such as total organic matter (TOM), oxidizable organic C (OxC), nonhydrolyzable carbon (NHC), P-Olsen, pH, soil moisture and soil water repellency (WR). In the unburned soil, most of these properties showed a decreasing gradient with depth which is modified after burning, in some cases inverted (as enzymatic activities and WR), in others intensified (P-Olsen) and in most, truncated, with a maximum value in the second cm. The depth of the soil in which changes were recorded varied according to the attibute considered; thus, burning significantly decreased only up to the first cm: bSR (73 %) and TOM (81 %), up to 2 cm: PHOase (89 %), OxC (17 %) and WR (96 %) and up to 3 cm depth GLUase (58 %), NHC (24 %) and moisture (73 %). However, P-Olsen and pH both increased after burning up to 1 and 3 cm soil depths, with increases of up to 240 % and 11 %, respectively. In conclusion, fire effects on soil are depth dependent, and this dependency is not uniform across soil properties

Hip Strength Disparities in College Soccer Players: Implications for Injury Risk and Conditioning Practices

The Y-balance Test (YBT) has been used to identify potential risk factors associated with lower extremity injuries (LEI), while mobility and strength assessments are often used to monitor progress following an injury. PURPOSE: This study aimed to explore differences in YBT scores along with lower body mobility and strength in Division I male soccer players who have reported a LEI in the last 12 months (LEI-Y) compared those without reported injuries (LEI-N). METHODS: Twenty-eight male soccer players (age: 20.7 ± 1.8 y; height: 183.8 ± 7.1 cm; mass: 78.5 ± 6.7 kg) completed pre-season evaluations which included YBT, hip strength, hamstring flexibility, and hip and ankle range of motion (ROM). All players were cleared for testing by the head athletic trainer and team physician and had no current LEI precluding them from participating. However, players self-reported if they had experienced a lower extremity injury or surgery in the prior twelve months. Hip adduction and abduction strength was evaluated using a dynamometer and calculated relative to body weight. Hip and ankle ROM were measured using a goniometer, and hamstring flexibility was measured using the sit-and-reach test. The YBT scores and leg length were used to determine a composite score for each leg. Data was presented as means ± standard deviations. RESULTS: For LEI-N, there were no notable imbalances in right to left side comparisons for hip adduction strength (44.8 ± 6.8 vs 43.5 ± 7.5 %) or hip abduction strength (49.2 ± 5.3 vs 49.0 ± 9.1 %). In the LEI-Y group, there was a discernible difference between the right and left side for hip adduction strength (43.7 ± 7.8 vs 41.4 ± 6.1 %) and hip abduction strength (48.4 ± 8.3 vs 45.1 ± 6.3 %). Relative hip strength and ankle ROM scores were also lower overall in the LEI-Y group compared to the LEI-N group, but no such trends were observed for YBT composite scores, hip ROM, or hamstring flexibility. CONCLUSION: The findings of this study indicate that the LEI-Y group had greater bilateral imbalance in lower limb strength, lower hip strength, and lower ankle ROM scores compared with those without injury history. Future research is recommended to evaluate the impact of injury on these markers and examine their associations with future injury risk

The effect of superplasticizers on the workability and compressive strength of concrete made with fine recycled concrete aggregates

The reuse of structural concrete elements to produce new concrete aggregates is accepted as an alternative to dumping them and is favourable to the sustainability of natural reserves. Even though the construction sector is familiar with the use of coarse recycled concrete aggregates, the recycled concrete fines are classified as less noble resources. This research sets out to limit the disadvantages associated with the performance of concrete containing fine recycled concrete aggregates through the use of superplasticisers. Two types of latest generation superplasticisers were used that differ in terms of water reduction capacity and robustness, and the workability, density and compressive strength of each of the compositions analysed were then compared: a reference concrete, with no plasticisers, and concrete mixes with the superplasticisers. For each concrete family mixes with 0%, 10%, 30%, 50% and 100% replacement ratios of fine natural aggregates (FNA) by fine recycled concrete aggregates (FRA) were analysed. Concrete with incorporation of recycled aggregates was found to have poorer relative performance. The mechanical performance of concrete with recycled aggregates and superplasticisers was generally superior to that of the reference concrete with no admixtures and of conventional concrete with lower performance superplasticisers