Phase only transmit beamforming for spectrum sharing microwave systems

This paper deals with the problem of phase-only transmit beamforming in spectrum sharing microwave systems. In contrast to sub-6 GHz schemes, general microwave systems require a large number of antennas due to its huge path loss. As a consequence, digital beamforming needs a large number of computational resources compared to analog beamforming, which only needs a single radio-frequency chain, results the less computational demanding solution. Analog schemes are usually composed by a phase shifter network whose elements transmit at a certain fixed power so that the system designer shall compute the phase values for each element given a set of directions. This approach leads to non-convex quadratic problems where the traditional semidefinite relaxation fails to deliver satisfactory outcomes. In order to solve this, we propose a nonsmooth method that behaves well in several scenarios. Numerical evaluations in different spectrum sharing scenarios, which show the performance of our method, are provided.Peer ReviewedPostprint (author's final draft

Observational data analysis using generalizability theory and general and mixed linear models: An empirical study of infant learning and development

Accurate evaluation of early childhood competencies is essential for favoring optimal development, as the first years of life form the foundations for later learning and development. Nonetheless, there are still certain limitations and deficiencies related to how infant learning and development are measured. With the aim of helping to overcome some of the difficulties, in this article we describe the potential and advantages of new data analysis techniques for checking the quality of data collected by the systematic observation of infants and assessing variability. Logical and executive activity of 48 children was observed in three ages (18, 21 and 24 months) using a nomothetic, follow-up and multidimensional observational design. Given the nature of the data analyzed, we provide a detailed methodological and analytical overview of generalizability theory from three perspectives linked to observational methodology: intra- and inter-observer reliability, instrument validity, and sample size estimation, with a particular focus on the participant facet. The aim was to identify the optimal number of facets and levels needed to perform a systematic observational study of very young children. We also discuss the use of other techniques such as general and mixed linear models to analyze variability of learning and development. Results show how the use of Generalizability Theory allows controlling the quality of observational data in a global structure integrating reliability, validity and generalizability. Una adecuada evaluación de las competencias infantiles tem-pranas es esencial para potenciar un desarrollo óptimo, pues los primeros años de vida son la base de todo el desarrollo y aprendizaje posterior. Sin embargo, todavía existen ciertas limitaciones y deficiencias en el ámbito de la medición del desarrollo y aprendizaje infantil. Con el objetivo último de contribuir a la mejora de esta situación, este trabajo presenta las posibilida-des y ventajas que ofrecen nuevas técnicas de análisis de datos, tanto para controlar la calidad de los datos infantiles registrados a través de observa-ción sistemática como para analizar su variabilidad. Se ha observado en tres edades diferentes (18, 21 y 24 meses) la actividad lógica y ejecutiva de 48 niños usando un diseño observacional nomotético, de seguimiento y mul-tidimensional. Dadas las particularidades de los datos del estudio que presentamos, desde el punto de vista metodológico y su análisis, realizamos análisis pormenori-zados a través de la Teoría de la Generalizabilidad en tres vertientes posi-bles en un estudio observacional: Análisis de la fiabilidad intra e inter-observadores, Análisis de la validez del instrumento de observación y Es-timación muestral de las facetas estudiadas (en concreto, la de participan-tes). De esta forma, se pretende optimizar el número de facetas y niveles necesarios para llevar a cabo un estudio de tales características. Además, se utilizan otras técnicas analíticas para conocer la variabilidad del desarrollo y aprendizaje infantil, como son el Modelo Lineal General y el Modelo MIXED. Los resultados indican cómo el uso de la Teoría de la Generalizabilidad permite controlar la calidad de los datos observacionales en una estructura única que integra la fiabilidad, validad y generalizabilidad

Rationalizing Systems Analysis for the Evaluation of Adaptation Strategies in Complex Human-Water Systems

Water resources management is a nontrivial process requiring a holistic understanding of the factors driving the dynamics of human-water systems. Policy-induced or autonomous behavioral changes in human systems may affect water and land management, which may affect water systems and feedback to human systems, further impacting water and land management. Currently, hydro-economic models lack the ability to describe such dynamics either because they do not account for the multifactor/multioutput nature of these systems and/or are not designed to operate at a river basin scale. This paper presents a flexible and replicable methodological framework for integrating a microeconomic multifactor/multioutput Positive Multi-Attribute Utility Programming (PMAUP) model with an eco-hydrologic model, the Soil and Water Assessment Tool (SWAT). The connection between the models occurs in a sequential modular approach through a common spatial unit, the “hydrologic-economic representative units” (HERUs), derived from the boundaries of decision-making entities and hydrologic responsive units. The resulting SWAT-PMAUP model aims to provide the means for exploring the dynamics between the behavior of socio-economic agents and their connection with the water system through water and land management. The integrated model is illustrated by simulating the impacts of irrigation restriction policies on the Río Mundo subbasin in south-eastern Spain. The results suggest that agents' adaptation strategies in response to the irrigation restrictions have broad economic impacts and subsequent consequences on surface and groundwater hydrology. We suggest that the integrated modeling framework can be a valuable tool to support decision-making in water resources management across a wide range of scales

Determinants and Tools to Evaluate the Ecological Sustainability of Using Forest Biomass as an Alternative Energy Source

Forest biomass, the most ancient of fuels, is again in the center of renewable energy production. This chapter provides an introductory view of the main factors that condition the ecological sustainability of this energy source. The basic concepts of ecological sustainability, ecological rotation, and ecological thresholds (among others) are presented. The state of the art on approaches to assess the sustainability of forest biomass production for heat and electricity is discussed, and tools available for decision-makers to evaluate the sustainability of forest biomass production and management are described. This chapter then describes the main advantages and drawbacks of forest certification, growth and yield tables, and ecological models in relationship to their use in sustainable forest management for biomass and energy production

Irrigation technology and water conservation: A review of the theory and evidence

Climate change, population growth, and economic development increase competition for water and exacerbate water scarcity- and drought-related losses (IPCC 2014), resulting in the identification of water crises as the greatest global societal threat (WEF 2019). Farming currently accounts for roughly 70 percent of freshwater withdrawals worldwide (FAO 2019) and often constitutes the least productive (i.e., lowest value) use of freshwater resources (Damania et al. 2017). In this context, providing safe, stable, and profitable food production while making incremental water available to alternative uses, including the environment, requires efficiency improvements in agricultural water management (UN 2015)

Some applications of the bootstrap in Spanish Discards Sampling Scheme

Herein we propose a nested boostrap scheme to explore di erent sources of variability in discard data. The proposed tool resamples on trips, hauls within trips and lengthclasess within hauls to include all sources of variability identified in the Spanish DCR sampling program scheme. Megrim (Lepidorhombus wiffiagonis) and Hake (Merluccius merluccius) discard data collected in 2008 from OTB-51 metier operating in ICES Division VI - VII, and Mediterranea DEF-Southern metier operating in the GSA 6S area were considered as case studies. Bootstrap Error and Coeficients of Variation associated to mean discards per trip were obtained and compared with asymptotic estimates. Furthermore, we use the bootstrap to quantify the contribution of the given sources of variability to global variability, and to assess simulated sampling scenarios differing each others in sampling effort. The last application of this method is for detecting outliers in 2008 sampled units (Trips). The good performance of the bootstrap method validates its use to obtain reliable error estimates in further regression and/or classiffication studies on discard data

Underlying molecular mechanism in the modulation of the ram sperm acrosome reaction by progesterone and 17ß-estradiol

Steroid hormones progesterone (P4) and 17ß-estradiol (E2) not only have important functions in regulation of reproductive processes in mammals but also have direct effects on spermatozoa. There can be induction of the acrosome reaction in ram spermatozoa by P4 and E2 and, in the present study, there was further investigation of mechanisms underlying this effect. In a medium containing agents that increase cAMP, the presence of both P4 and E2 led to changes in the localization of proteins phosphorylated in tyrosine residues evaluated by indirect immunofluorescence. The inclusion of P4 at 1 µM in the media induced an increase in Ca2+i and mobilization in the area of the acrosome (Fluo-4 and Rhod-5 staining, respectively), an increase in ROS (H2DCFDA staining) and a substantial disruption of the acrosome (evaluated using RCA), while E2 did not have these effects. There were no effects on cAMP concentrations or PKA activity with inclusion of these hormones in the media. The inclusion of P4 at 100 pM in the media led to changes in values for sperm kinematic variables which could indicate there was an inhibition of the hyperactivation caused by agents that induce an increase in cAMP concentrations. In conclusion, results from the present study indicate that P4 and E2 promote mechanisms regulating the acrosome reaction in ram spermatozoa, however, these effects on mechanisms are different for the two hormones, and for E2, require further clarification