Minimización global de un polinomio en la recta real

En este art´ıculo presentamos y probamos num´ericamente un nuevo algoritmo para la minimizaci´on global de un polinomio de grado par. El algoritmo est´a basado en la simple idea de trasladar verticalmente el grafo del polinomio hasta que el eje OX sea tangente al grafo del polinomio trasladado. En esta privilegiada posici´on, cualquier ra´ız real del polinomio trasladado es un m´ınimo global del polinomio original

Response of potential cucurbit rootstocks against Meloidogyne spp

the Cucurbita hybrids, usually used as cucurbit rootstocks, are susceptible to Meloidogyne. Its cultivation increases the nematode population densities at similar levels than ungrafted cucumber or melon crops, and higher 'Ievels than watermelon.Postprint (published version

Grafting melons onto potential cucumis spp. rootstocks

Cucumís melo is an economically importar]t crop. Its culture is hampered by differen t types of soil stresses. Grafting melons onto different resistant cucurbits belonging to the genera, Cucurbíta, Lagenaría, Luffa, etc. have been successfully used to avoid these problems. However, me Ion quality has been nega.tively modified as a consequence of grafting. In general, variation in fruit shape, seed cavity and sugar content have been observed. The use of rootstocks more genetically c\oser to the melon scions could be useful to obtain fru i ts with better quality from melon grafted plantsPostprint (published version

Authoritarianism versus participation in innovation decisions

Why do innovation projects fail? The most common answers are (A) the implementation differs from what was planned; (B) despite positive expected payoffs, there is an ex-ante positive probability that payoff can be negative (risk). As a third option, we consider the fallibility of individuals who evaluate innovation projects using their limited information-processing capabilities (bounded rationality). Furthermore, we compare the overall organizational performance of two decision mechanisms. First, an informal Collective Decision as an unanimity participative mechanism to decide on technological innovation adoption and, second, a centralized Authority decision. Authority-based decision-making results in higher commission errors (acceptance of projects that an unbounded rational decision-maker would reject) and lower omission errors (rejection of projects that an unbounded rational decision-maker would accept) than Collective Decision. In a dynamic technological adoption process where a sequence of randomly generated innovation projects is evaluated using the two mechanisms, the simulations show that, in the short-term, omission errors dominate and Authority is preferred to Collective Decision; however, in the mid and long terms, commission errors dominate and Collective Decision is preferred to Authority, especially if Collective Decision does not incorporate social influence. With Collective Decision, the ratio of projects that fail is lower, more innovation projects are rejected, and fewer innovation projects are accepted, which can be interpreted as resistance to innovation

The role of the organization structure in the diffusion of innovations

Diffusion and adoption of innovations is a topic of increasing interest in economics, market research, and sociology. In this paper we investigate, through an agent based model, the dynamics of adoption of innovative proposals in different kinds of structures. We show that community structure plays an important role on the innovation diffusion, so that proposals are more likely to be accepted in homogeneous organizations. In addition, we show that the learning process of innovative technologies enhances their diffusion, thus resulting in an important ingredient when heterogeneous networks are considered. We also show that social pressure blocks the adoption process whatever the structure of the organization. These results may help to understand how different factors influence the diffusion and acceptance of innovative proposals in different communities and organizations

An assessment for UAS depart and approach operations

Unmanned Aerial Systems (UAS) have great potential to be used in a wide variety of civil applications such as environmental applications, emergency situations, surveillance tasks and more. The development of Flight Control Systems (FCS) coupled with the availability of other Commercial Off-The Shelf (COTS) components is enabling the introduction of UAS into the civil market. The sophistication of existing FCS is also making these systems accessible to end users with little aeronautics expertise. However, much work remains to be done to deliver systems that can be properly integrated in standard aeronautical procedures used by manned aviation. In previous research advances have been proposed in the flight plan capabilities by offering semantically much richer constructs than those present in most current UAS autopilots. The introduced flight plan is organized as a set of stages, each one corresponding to a different flight phase. Each stage contains a structured collection of legs inspired by current practices in Area Navigation (RNAV). However, the most critical parts of any flight, the depart and approach operations in an integrated airspace remain mostly unexplored. This paper introduces an assessment of both operations for UAS operating in VFR and IFR modes. Problems and potential solutions are proposed, as well as an automating strategy that should greatly reduce pilot workload. Although th

High-sensitivity large-area photodiode read-out using a divide-and-conquer technique

In this letter, we present a novel technique to increase the sensitivity of optical read-out with large integrated photodiodes (PD). It consists of manufacturing the PD in several pieces, instead of a single device, and connecting a dedicated transimpedance amplifier (TIA) to each of these pieces. The output signals of the TIAs are combined, achieving a higher signal-to-noise ratio than with the traditional approach. This work shows a remarkable improvement in the sensitivity and transimpedance without the need for additional modifications or compensation techniques. As a result, an increase in sensitivity of 7.9 dBm and transimpedance of 8.7 dBO for the same bandwidth is achieved when dividing the photodiode read-out into 16 parallel paths. The proposed divide-and-conquer technique can be applied to any TIA design, and it is also independent of the core amplifier structure and fabrication process, which means it is compatible with every technology allowing the integration of PDs

Programmable low-power low-noise capacitance to voltage converter for MEMS accelerometers

In this work, we present a capacitance-to-voltage converter (CVC) for capacitive accelerometers based on microelectromechanical systems (MEMS). Based on a fully-differential transimpedance amplifier (TIA), it features a 34-dB transimpedance gain control and over one decade programmable bandwidth, from 75 kHz to 1.2 MHz. The TIA is aimed for low-cost low-power capacitive sensor applications. It has been designed in a standard 0.18-µm CMOS technology and its power consumption is only 54 µW. At the maximum transimpedance configuration, the TIA shows an equivalent input noise of 42 fA/vHz at 50 kHz, which corresponds to 100 µg/vHz

Actitudes de los consumidores y productores hacia la carne de cordero de raza Ojinegra de Teruel

raza Ojinegra de TeruelPublishe