The design, construction, operation, and maintenance of the Replicated Modular Estuarine Mesocosm

Perhaps the most difficult job of the ecotoxicologist is extrapolating data calculated from laboratory experiments with high precision and accuracy into the real world of highly-dynamics aquatic environments. The establishment of baseline laboratory toxicity testing data for individual compounds and ecologically important and field studies serve as a precursor to ecosystem level studies needed for ecological risk assessment. The first stage in the field portion of risk assessment is the determination of actual environmental concentrations of the contaminant being studied and matching those concentrations with laboratory toxicity tests. Risk estimates can be produced via risk quotients that would determine the probability that adverse effects may occur. In this first stage of risk assessment, environmental realism is often not achieved. This is due, in part, to the fact that single-species laboratory toxicity tests, while highly controlled, do not account for the complex interactions (Chemical, physical, and biological) that take place in the natural environment. By controlling as many variables in the laboratory as possible, an experiment can be produced in such a fashion that real effects from a compound can be determined for a particular test organism. This type of approach obviously makes comparison with real world data most difficult. Conversely, field oriented studies fall short in the interpretation of ecological risk assessment because of low statistical power, lack of adequate replicaiton, and the enormous amount of time and money needed to perform such studies. Unlike a controlled laboratory bioassay, many other stressors other than the chemical compound in question affect organisms in the environment. These stressors range from natural occurrences (such as changes in temperature, salinity, and community interactions) to other confounding anthropogenic inputs. Therefore, an improved aquatic toxicity test that will enhance environmental realism and increase the accuracy of future ecotoxicological risk assessments is needed.

Estudio morfológico y taxonómico de los ampulláridos de la República Argentina: Maria Isabel Hylton Scott. [tomado de la Revista del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”, Ciencias Zoologicas, Tomo III, nº 5, 1957.]

Corría 1968. Yo era un estudiante enamorado de las ampularias, y alguien me regaló una separata del trabajo de María Isabel Hylton Scott titulado “Estudio morfológico y taxonómico de los ampulláridos de la República Argentina”. Hoy soy un profesor e investigador jubilado, … enamorado de las ampularias ¿Qué pasó en el medio? Por diversas circunstancias de mi vida comencé mi carrera estudiando roedores. Pero como canta un tango, “siempre se vuelve al primer amor” y dos décadas después (hacia 1990) conseguí algo de financiación para estudiar uno de estos extraordinarios animales: Pomacea canaliculata. Esto fue para mí un nuevo comienzo: poco a poco fui dejando mis estudios en ratones silvestres, y formando un grupo dedicado a esta ampularia ¡Fue un cambio de phylum! Pecado difícilmente perdonable en un ambiente científico cada vez más competitivo, pero que me llenó de satisfacción, por lo que me felicito de haberlo cometido. Desde entonces he dirigido a siete doctorandos en distintos aspectos de la morfología y la ecofisiología de este animal (Albrecht, 1998; Vega, 2005; Gamarra-Luques, 2007; Koch, 2008; Giraud-Billoud, 2009; Cueto, 2011; Giraud-Billoud, 2011), y sus tesis tienen al menos dos cosas en común: P. canaliculata casi siempre en el título, y el trabajo de Hylton Scott (1957) siempre citado en la bibliografía. Ella, “la doctora”, la “decana de los zoólogos argentinos” (como escribió Cazzaniga, 1991) fue para nosotros, atrevidos que no la conocimos personalmente, a quien llamábamos por sobrenombre “Doña Marisa”, y lo seguimos haciendo. Lo sigo haciendo yo, porque aunque jubilado “en los papeles”, sigo trabajando detrás de sus pasos. Hoy tengo un doctorando (C. Rodríguez) trabajando en P. canaliculata , el octavo de mis tesistas en esta especie, y deseo que no sea el último. Una revisión de la biología de ampuláridos actualmente en prensa en Malacologia (Hayes et al., 2015) cita repetidas veces el trabajo que hoy reedita ProBiota. Los autores provienen de un amplio “mundo”, porque “el mundo” de los ampuláridos se ha extendido antropocóricamente a lo que hoy es Estados Unidos, Europa, China y Japón. Esto no lo podría haber soñado Doña Marisa cuando comenzó sus pacientes estudios de la embriología de P. canaliculata hace ochenta años (Hylton Scott, 1934). Y si algún cientómetra quisiera calcular la vida media de sus citas, se encontraría con algo sorprendente: que la curva temporal de éstas no va decayendo ¡sino creciendo! Hoy no puedo imaginarme a mí mismo, como investigador, si no me hubiera topado con esa separata de cien páginas, escritas en un castellano elegante y hoy amarillentas, a las que guardo como un tesoro (porque las que usamos son sus fotocopias). Por eso, al acercarse los 25 años de la muerte de esta gran cordobesa (y platense por adopción) le propuse a mi amigo Hugo L. López esta reedición, que el aceptó con entusiasmo. Y también le propuse a mi alumno G. I. Prieto, excelente dibujante, que le diera nueva vida a una vieja foto de Doña Marisa que fue publicada por Cazzaniga (1992). Los que conocieron a “la doctora” personalmente, podrán decir si Prieto logró revivir su penetrante mirada. Creo que sí. Alfredo Castro-Vazquez

Heuristics for Job-Shop Scheduling

Two methods of obtaining approximate solutions to the classic General Job-shop Scheduling Program are investigated. The first method is iterative. A sampling of the solution space is used to decide which of a collection of space pruning constraints are consistent with "good" schedules. The selected space pruning constraints are then used to reduce the search space and the sampling is repeated. This approach can be used either to verify whether some set of space pruning constraints can prune with discrimination or to generate solutions directly. Schedules can be represented as trajectories through a Cartesian space. Under the objective criteria of Minimum maximum Lateness family of "good" schedules (trajectories) are geometric neighbors (reside with some "tube") in this space. This second method of generating solutions takes advantage of this adjacency by pruning the space from the outside in thus converging gradually upon this "tube." One the average this methods significantly outperforms an array of the Priority Dispatch rules when the object criteria is that of Minimum Maximum Lateness. It also compares favorably with a recent relaxation procedure.

Produção de uvas para processamento no sistema de condução Scott Henry, em região tropical do Brasil.

2007

Job change and workplace learning in the public sector: the significance of new technology for unskilled work.

Focussing here on local authorities and health services, this paper examines the significance of new technology to unskilled work in the public sector as it is developing and the implications for workplace learning. An argument is developed that new technology is central to a minority of examples of job change, although, significantly, it is more important to staff–initiated change and to workers’ ability to fully participate in life beyond the workplace.

Roll Project Job Shop scheduling benchmark problems.

This document describes two sets of benchmark problem instances for the job shop scheduling problem. Each set of instances is supplied as a compressed (zipped) archive containing a single CSV file for each problem instance using the format described in http://rollproject.org/jssp/jsspGen.pdf

A hyper-heuristic ensemble method for static job-shop scheduling.

We describe a new hyper-heuristic method NELLI-GP for solving job-shop scheduling problems (JSSP) that evolves an ensemble of heuristics. The ensemble adopts a divide-and-conquer approach in which each heuristic solves a unique subset of the instance set considered. NELLI-GP extends an existing ensemble method called NELLI by introducing a novel heuristic generator that evolves heuristics composed of linear sequences of dispatching rules: each rule is represented using a tree structure and is itself evolved. Following a training period, the ensemble is shown to outperform both existing dispatching rules and a standard genetic programming algorithm on a large set of new test instances. In addition, it obtains superior results on a set of 210 benchmark problems from the literature when compared to two state-of-the-art hyperheuristic approaches. Further analysis of the relationship between heuristics in the evolved ensemble and the instances each solves provides new insights into features that might describe similar instances.

Letter: To Ebenezer Blackwell from John Wesley, July 3, 1751

Digitized from a letter in the Drew University Methodist Collection. 1 item (4 p.); 19.5 x 32 cm.

Letter: To Molly Wesley from John Wesley, March 30, 1751

Digitized from a letter in the Drew University Methodist Collection. 1 Item (4 p.); 20.5 x 33 cm.