Injection statistics simulator for dynamic analysis of noise in mesoscopic devices

We present a model for electron injection from thermal reservoirs which is applied to particle simulations of one-dimensional mesoscopic conductors. The statistics of injected carriers is correctly described from nondegenerate to completely degenerate conditions. The model is validated by comparing Monte Carlo simulations with existing analytical results for the case of ballistic conductors. An excellent agreement is found for average and noise characteristics, in particular, the fundamental unities of electrical and thermal conductances are exactly reproduced.Comment: 4 pages, revtex, 4 PS figures, accepted Semicond. Sci. Techno

Teleological structure of scientific and mathematical education

One of the main educational objectives in the current Spanish curricula is to develop mathematical and scientific competences, understood as the set of skills and abilities needed to apply Mathematics and Science in situations where are required. This is therefore closely related, on one hand, to the functionality of the knowledge, in the sense of its usefulness in problem solving and in mathematical and science modeling problems. And, on the other hand, is related to the understanding of disciplinary knowledge, a cognitive phenomenon that enables and gives competence to the individual to elaborate contextualized and accurate answers. These answers involve the use of mathematical and scientific knowledge in some of the categories of their phenomenological and epistemological dimensions. For this reason, in this work we carry out a theoretical and reflexive analysis that tries to determine which aspects of the Mathematics and Science Education should be promoted in order to optimize the formative dimension of an individual in these disciplines. This dimension, frequently forgotten in learning and teaching processes, turns out to be, in conjunction with the functional and instrumental dimensions, necessary to acquire the appropriate knowledge in Mathematics and Science that will enable future citizens to permanently adapt to the environment and eventually transform it positively. The results of the analysis show the components of this dimension that should be prioritized in the Science and Mathematics Education: the intellectual autonomy, understood as the ability to think for ourselves and to put in use our abilities and skills to generate information to solve real life problems and to make the right decisions; the moral autonomy, defined as the capacity to face with real life problems with ethical implications; and the social autonomy, understood as the aptitude to make decisions using social abilities and skills.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.“Criterios e instrumentos de evaluación de unidades de enseñanza y aprendizaje” (PPIT.UMA.B1.2017/16) financiado por la Universidad de Málaga en la convocatoria de 2017-2018

High-J v=0 SiS Maser Emission in IRC+10216: A New Case of Infrared Overlaps

We report on the first detection of maser emission in the J=11-10, J=14-13 and J=15-14 transitions of the v=0 vibrational state of SiS toward the C-rich star IRC+10216. These masers seem to be produced in the very inhomogeneous region between the star and the inner dust formation zone, placed at 5-7 R*, with expansion velocities below 10 km/s. We interpret the pumping mechanism as due to overlaps between v=1-0 ro-vibrational lines of SiS and mid-IR lines of C2H2, HCN and their 13C isotopologues. The large number of overlaps found suggests the existence of strong masers for high-J v=0 and v=1 SiS transitions, located in the submillimeter range. In addition, it could be possible to find several rotational lines of the SiS isotopologues displaying maser emission.Comment: 4 pages, 1 figure, published in the ApJ Letter

An Empirical Study on Collective Intelligence Algorithms for Video Games Problem-Solving

Computational intelligence (CI), such as evolutionary computation or swarm intelligence methods, is a set of bio-inspired algorithms that have been widely used to solve problems in areas like planning, scheduling or constraint satisfaction problems. Constrained satisfaction problems (CSP) have taken an important attention from the research community due to their applicability to real problems. Any CSP problem is usually modelled as a constrained graph where the edges represent a set of restrictions that must be verified by the variables (represented as nodes in the graph) which will define the solution of the problem. This paper studies the performance of two particular CI algorithms, ant colony optimization (ACO) and genetic algorithms (GA), when dealing with graph-constrained models in video games problems. As an application domain, the "Lemmings" video game has been selected, where a set of lemmings must reach the exit point of each level. In order to do that, each level is represented as a graph where the edges store the allowed movements inside the world. The goal of the algorithms is to assign the best skills in each position on a particular level, to guide the lemmings to reach the exit. The paper describes how the ACO and GA algorithms have been modelled and applied to the selected video game. Finally, a complete experimental comparison between both algorithms, based on the number of solutions found and the levels solved, is analysed to study the behaviour of those algorithms in the proposed domain

06/07/1995 - Nolan Recipient Of Chemistry Awards.pdf

International audienc

Is Inappropriate Documentation of Penicillin Allergy Related to Overuse of Aztreonam?

Background: Penicillin allergy is one of the most common drug allergies, with a 10% prevalence in the United States. Only 10% of patients who self-report a penicillin allergy will react if given penicillin, and only 1% will experience an Immunoglobulin E (IgE) mediated reaction if exposed to a cephalosporin or carbapenem. These patients who self-report a penicillin allergy are commonly treated with second line antibiotics such as aztreonam, leading to unnecessary adverse events, the development of resistant organisms such as vancomycin-resistant enterococci (VRE), and an increased prevalence of Clostridioi-des difficile infections (CDI). A “Beta lactam allergy assessment and alternatives to aztreonam” protocol was implemented at Homestead Hospital (HH), in order to minimize aztreonam usage while optimizing antimicrobial therapy. Despite improvements in the susceptibility rates of Pseudomonas aeruginos a to aztreonam from 59% in 2016 to 64% in 2017, HH continues to have the lowest susceptibility rate within the Baptist Health South Florida (BHSF) system, which might be attributed to the over-use of this antibiotic. Purpose: This study is to determine whether aztreonam overuse is directly associated with inappropriate allergy assessment and documentation. In addition to evaluate the existing penicillin allergy documentation at HH in order to improve the current “Beta lactam allergy assessment and alternatives to aztreonam” protocol. Methods: A retrospective chart review of 154 patients who received aztreonam from June 1 2017 to July 31 2018 was done. Patients 18 years and older who received aztreonam within the aforementioned time frame were included in the study. Each chart was reviewed to determine appropriateness of allergy documentation, previous beta lactam administration and tolerance, concomitant antibiotic use, and appropriateness of aztreonam indication. The use of aztreonam was considered inappropriate in the absence of a documented severe penicillin allergy or in patients for whom beta lactam antibiotics were administered without an allergic reaction according to current guidelines and HH protocols. The criteria used to assess allergy documentation were severity and description of event in accordance to the HH protocol. Results: At HH, 149 (96.75%) patients receiving aztreonam self-reported a penicillin allergy, and 65 (44%) patients received a beta lactam despite self-reporting a penicillin allergy, from which 63 (97%) of them tolerated the antibiotic uneventfully. 84 (56%) patients reporting a penicillin allergy did not receive a beta lactam antibiotic. Of these, only 19 (23%) reported a severe penicillin allergic reaction. Beta lactams administered to patients who self-reported a penicillin allergy included 3 rd generation cephalosporins (37%), carbapenems (34%), and 4 generation cephalosporin (31%). Allergies were inappropriately documented in 77 (50%) patients, with description of allergy being the most common missing parameter. 127 (85%) patients received multiple antibiotics. 32 (21%) patients received one additional antibiotic; 50 (32.5%) received two antibiotics; 39 (25%) received a combination of three antibiotics, and 6 (4%) received 4 antibiotics. The most common antimicrobial agents were vancomycin, levofloxacin and clindamycin. 73 (53%) patients receiving aztreonam were prescribed a second line agent due to the monobactam’s narrow spectrum of coverage. Aztreonam was inappropriately used in 133 (87%) patients. The indication assessment for this antibiotic was not feasible in 8 (5%) patients due to inappropriate allergy documentation. Conclusions: In this retrospective chart review it was found that inappropriate penicillin allergy documentation leads to aztreonam overuse. Due to the narrow spectrum of coverage of aztreonam, patients required multiple antibiotics, including vancomycin, levofloxacin, and clindamycin. Although the impact of this on drug resistance such as VRE, CDI prevalence, and antibiotic-associated adverse events was not an endpoint in our study, we acknowledge these are potential consequences of inappropriately labeling patients with penicillin allergy. Further studies addressing the implications of multiple antibiotic use in patients self-reporting a penicillin allergy is recommended

Quantitative Analysis and Performance Study of Ant Colony Optimization Models Applied to Multi-Mode Resource Constraint Project Scheduling Problem

Constraint Satisfaction Problems (CSP) belongs to this kind of traditional NP-hard problems with a high impact in both, research and industrial domains. However, due to the complexity that CSP problems exhibit, researchers are forced to use heuristic algorithms for solving the problems in a reasonable time. One of the most famous heuristic al- gorithms is Ant Colony Optimization (ACO) algorithm. The possible utilization of ACO algorithms to solve CSP problems requires the de- sign of a decision graph where the ACO is executed. Nevertheless, the classical approaches build a graph where the nodes represent the vari- able/value pairs and the edges connect those nodes whose variables are different. In order to solve this problem, a novel ACO model have been recently designed. The goal of this paper is to analyze the performance of this novelty algorithm when solving Multi-Mode Resource-Constraint Satisfaction Problems. Experimental results reveals that the new ACO model provides competitive results whereas the number of pheromones created in the system is drastically reduced

Comparative study of pheromone control heuristics in ACO algorithms for solving RCPSP problems

Constraint Satisfaction Problems (CSP) belong to a kind of traditional NP-hard problems with a high impact on both research and industrial domains. The goal of these problems is to find a feasible assignment for a group of variables where a set of imposed restrictions is satisfied. This family of NP-hard problems demands a huge amount of computational resources even for their simplest cases. For this reason, different heuristic methods have been studied so far in order to discover feasible solutions at an affordable complexity level. This paper elaborates on the application of Ant Colony Optimization (ACO) algorithms with a novel CSP-graph based model to solve Resource-Constrained Project Scheduling Problems (RCPSP). The main drawback of this ACO-based model is related to the high number of pheromones created in the system. To overcome this issue we propose two adaptive Oblivion Rate heuristics to control the number of pheromones: the first one, called Dynamic Oblivion Rate, takes into account the overall number of pheromones produced in the system, whereas the second one inspires from the recently contributed Coral Reef Optimization (CRO) solver. A thorough experimental analysis has been carried out using the public PSPLIB library, and the obtained results have been compared to those of the most relevant contributions from the related literature. The performed experiments reveal that the Oblivion Rate heuristic removes at least 79% of the pheromones in the system, whereas the ACO algorithm renders statistically better results than other algorithmic counterparts from the literature