Length-weight relationship and relative condition factor of the Stone Scorpionfish Scorpaena mystes in the central area of the Gulf of California, Mexico

Background. In recent years (since 2012) there has been an increase in the commercial exploitation of Scorpaena mystes Jordan & Starks, 1985 in the central area of the Gulf of California and there is no information on the basic biology of this species that serve as a basis to determine the current population status and, in the future, assess any changes associated with exploitation and environmental factors. Goals. Determine the length-weight (LWR) and length-length (LLR) relationships, and the relative condition factor of S. mystes. Methods. Fish specimens (n = 258) were collected monthly from May 2015 through April 2016 in waters off Santa Rosalía, Baja California Sur. Each fish was measured for standard length (SL) and total length (TL), and weighed (W). Results. LWR and LLR were highly significant (p <0.05) with a determination coefficient higher than 0.9. The b-value (b = 3.06) of LWR was not significantly-different from 3. Monthly variation in the relative condition factor was also significant (p <0.05) with the highest value in August (1.34). Conclusions. The growth of S. mystes is isometric. The monthly variation in the condition factor may be associated with maturation of the gonads of the species.Background. In recent years (since 2012) there has been an increase in the commercial exploitation of Scorpaena mystes Jordan & Starks, 1985 in the central area of the Gulf of California and there is no information on the basic biology of this species that serve as a basis to determine the current population status and, in the future, assess any changes associated with exploitation and environmental factors. Goals. Determine the length-weight (LWR) and length-length (LLR) relationships, and the relative condition factor of S. mystes. Methods. Fish specimens (n = 258) were collected monthly from May 2015 through April 2016 in waters off Santa Rosalía, Baja California Sur. Each fish was measured for standard length (SL) and total length (TL), and weighed (W). Results. LWR and LLR were highly significant (p <0.05) with a determination coefficient higher than 0.9. The b-value (b = 3.06) of LWR was not significantly-different from 3. Monthly variation in the relative condition factor was also significant (p <0.05) with the highest value in August (1.34). Conclusions. The growth of S. mystes is isometric. The monthly variation in the condition factor may be associated with maturation of the gonads of the species

Novos algoritmos para o problema de sequenciamento em M?quinas Paralelas n?o relacionadas com tempos de prepara??o dependentes da sequ?ncia.

Programa de P?s-Gradua??o em Ci?ncia da Computa??o. Departamento de Ci?ncia da Computa??o, Instituto de Ci?ncias Exatas e Biol?gicas, Universidade Federal de Ouro Preto.Este trabalho trata o Problema de Sequenciamento em M?quinas Paralelas N?o- Relacionadas com Tempos de Prepara??o Dependentes da Sequ?ncia (UPMSPST, do ingl?s Unrelated Parallel Machine Scheduling Problem with Setup Times), objetivando minimizar o makespan. Para resolv?-lo foram desenvolvidos tr?s algoritmos heur?sticos e um algoritmo h?brido. O primeiro algoritmo heur?stico, denominado HIVP, tem uma solu??o inicial gerada por um procedimento construtivo parcialmente guloso baseado no m?todo Heuristic-Biased Stochastic Sampling e na regra Adaptive Shortest Processing Time { ASPT. Essa solu??o e, posteriormente, refinada pelo procedimento Iterated Local Search { ILS, tendo o Random Variable Neighborhood Descent como m?todo de busca local. Al?m disso, periodicamente a busca ? intensificada e diversificada por meio de um procedimento Path Relinking { PR. No segundo algoritmo heur?stico, denominado GIAP, a solu??o inicial ? criada por um procedimento inspirado no Greedy Randomized Adaptive Search Procedures. Nesse segundo algoritmo, a solu??o ? refinada por um procedimento ILS que utiliza como m?todo de busca local o procedimento Adaptive Local Search { ALS. A busca _e tamb?m intensificada e diversificada por meio de um procedimento PR. O terceiro e ?ltimo algoritmo heur?stico, denominado AIRP, tem sua solu??o inicial gerada por um procedimento construtivo guloso baseado na regra ASPT. Essa solu??o ? refinada por um procedimento ILS que tem como busca local um procedimento chamado RIV. De forma an?loga aos algoritmos anteriores, a busca tamb?m passa por uma intensifica??o ao e diversifica??o periodicamente por meio de um procedimento PR. O algoritmo h?brido, denominado AIRMP, tem o funcionamento similar ao do algoritmo heur?stico AIRP, diferindo deste por acrescentar um m?dulo de programa??o linear inteira mista. Para a aplica??o desse m?dulo s?o selecionados um par de m?quinas e subconjuntos de tarefas nessas m?quinas. Esses subconjuntos s?o combinados e passam por uma busca local que consiste em acionar um resolvedor de programa??o matem?tica aplicado a melhor das formula??es de programa??o matem?tica dentre aquelas estudadas e desenvolvidas. Pelos experimentos computacionais foi poss?vel concluir que o AIRP obteve os melhores resultados dentre os algoritmos heur?sticos propostos, conseguindo superar v?rios outros algoritmos da literatura. Tamb?m foram realizados experimentos para comparar os algoritmos AIRMP e AIRP. Como o AIRMP necessita de um tempo maior para acionar o m?dulo de programa??o matem?tica, esses experimentos utilizaram um tempo maior de execu??o. Observou-se, no entanto, que a adi??o do m?dulo de programa??o matem?tica n?o melhorou o desempenho do AIRMP no tempo testado e na estrutura utilizada de subconjuntos de tarefas. Esses testes tamb?m mostraram que aumentando-se o tempo de processamento do AIRP, o algoritmo e capaz de encontrar melhores solu??es.This paper deals with the Unrelated Parallel Machine Scheduling Problem with Setup Times { UPMSPST, having as goal to minimize the makespan. In order to solve it, three heuristic algorithms and a hybrid algorithm were developed. The first heuristic algorithm, called HIVP, has an initial solution generated by a greedy constructive procedure based on the Heuristic-Biased Stochastic Sampling and on the Adaptive Shortest Processing Time { ASPT rule. This solution is then refined by the Iterated Local Search { ILS procedure, having the Random Variable Neighborhood Descent as local search method. Moreover, the search is periodically intensified and diversified by a Path Relinking { PR procedure. In the second algorithm, called GIAP, the initial solution is created by a procedure inspired on the Greedy Randomized Adaptive Search Procedures. This solution is then refined by an ILS procedure that uses the procedure Adaptive Local Search { ALS as local search method. The search is also intensified and diversified by a PR procedure. The third and final heuristic algorithm, called AIRP, has its initial solution generated by a greedy constructive procedure based on ASPT rule. This solution is then refined by the ILS, having as local search a procedure called RVI. Analogously to the previous algorithms, the search also applies periodically an intensification and diversification strategy based on the PR procedure. The hybrid algorithm, named AIRMP, is similar to the AIRP heuristic algorithm, differing from it by adding a module of mixed integer linear programming. To apply this module one pair of machines are selected and subsets of jobs of these machines. These subsets are combined and they pass through a local search that consists in running a mathematical programming solver applied to the best formulation among the studied and developed ones. By computational experiments it was concluded that the AIRP algorithm obtained the best results among the proposed heuristic algorithms, outperforming several other algorithms from the literature. Experiments were also conducted to compare the AIRMP and AIRP algorithms. As the AIRMP needs more time to execute the mathematical programming module, these experiments utilized a higher runtime. It was observed, however, that the addition of the mathematical programming module does not improved the performance of the AIRMP algorithm in the tested time and in the used structure of subsets of jobs. These tests also showed that increasing the processing time of the AIRP, the algorithm is able to find better solutions

Quantum dynamics, dissipation, and asymmetry effects in quantum dot arrays

We study the role of dissipation and structural defects on the time evolution of quantum dot arrays with mobile charges under external driving fields. These structures, proposed as quantum dot cellular automata, exhibit interesting quantum dynamics which we describe in terms of equations of motion for the density matrix. Using an open system approach, we study the role of asymmetries and the microscopic electron-phonon interaction on the general dynamical behavior of the charge distribution (polarization) of such systems. We find that the system response to the driving field is improved at low temperatures (and/or weak phonon coupling), before deteriorating as temperature and asymmetry increase. In addition to the study of the time evolution of polarization, we explore the linear entropy of the system in order to gain further insights into the competition between coherent evolution and dissipative processes.Comment: 11pages,9 figures(eps), submitted to PR

Quasienergy spectrum and tunneling current in ac-driven triple quantum dot shuttles

The dynamics of electrons in ac driven double quantum dots have been extensively analyzed by means of Floquet theory. In these systems, coherent destruction of tunneling has been shown to occur for certain ac field parameters. In the present work we analyze, by means of Floquet theory, the electron dynamics of a triple quantum dot in series attached to electric contacts, where the central dot position oscillates. In particular, we analyze the quasienergy spectrum of this ac driven nanoelectromechanical system, as a function of the intensity and frequency of the ac field and of external dc voltages. For strong driving fields, we derive, by means of perturbation theory, analytical expressions for the quasienergies of the driven oscillator system. From this analysis we discuss the conditions for coherent destruction of tunneling (CDT) to occur as a function of detuning and field parameters. For zero detuning, and from the invariance of the Floquet Hamiltonian under a generalized parity transformation, we find analytical expressions describing the symmetry properties of the Fourier components of the Floquet states under such transformation. By using these expressions, we show that in the vicinity of the CDT condition, the quasienergy spectrum exhibits exact crossings which can be characterized by the parity properties of the corresponding eigenvectors

Histórico e perspectivas das doenças na cultura do milho.

bitstream/item/95066/1/circ-193.pd

Microstructural characterization of bainitic steel submitted to torsion testing and interrupted accelerated cooling.

HSLA low-carbon bainitic steel containing B was submitted to torsion tests to simulate controlled rolling, followed by interrupted accelerated cooling. Microstructural characteristics and the mechanisms for the refinement of structure were evaluated using light microscopy, scanning electron microscopy, transmission electron microscopy, and Vickers hardness testing. The final microstructure was found to contain complex mixture of granular bainite, small islands of MA constituent, bainitic ferrite, and polygonal ferrite. Increasing the cooling rate or decreasing the finish cooling temperature resulted in a decrease in the volume fraction and average size of the MA islands and the polygonal ferrite. A finish cooling temperature of 400 8 C produced a microstructure consisting of fine laths of bainitic ferrite with an interlath MA constituent. A quantitative relationship between the accelerated cooling variables and the ferrite grain size was developed

Nutrient and biogenic particulate distributions, primary productivity and nitrogen uptake in the Weddell-Scotia Sea marginal ice zone during winter

During austral winter of 1988, we determined the distributions of inorganic nutrients (nitrate, silicic acid, phosphate, nitrite and ammonium) and particulate materials (chlorophyll, biogenic silica, particulate organic carbon and particulate organic nitrogen), as well as primary productivity and rates of nutrient (NO3− and NH4+) uptake in the upper 150 m of the marginal ice zone of the Weddell-Scotia Sea. Nutrient concentrations were high and particulate matter levels were low throughout the study area, but occasionally nutrient minima and particulate maxima occurred near the ice edge associated with warm-core eddies. Chlorophyll concentrations and primary productivity averaged 0.12 μg l−1 and 32 mg C m−2 d−1, respectively. Surface growth rates calculated from carbon uptake and total particulate organic carbon were very low (ca. 0.03 doublings d−1), but living phytoplankton only comprised about 10% of the POC in the surface layer. Thus, mean phytoplankton growth rates appear to have been between 0.1 and 0.2 doublings d−1. Although nitrate was about 40 times as abundant as ammonium, ammonium was consistently the preferred substrate of the plankton assemblages, accounting for over half of the nitrogen taken up. Paired samples from the same depth and vertically integrated f-ratios averaged 0.43. Both ammonium and nitrate were removed at rates that individually exceeded the apparent nitrogen demand of the phytoplankton, implying significant heterotrophic uptake of inorganic nitrogen

Scalar-field Pressure in Induced Gravity with Higgs Potential and Dark Matter

A model of induced gravity with a Higgs potential is investigated in detail in view of the pressure components related to the scalar-field excitations. The physical consequences emerging as an artifact due to the presence of these pressure terms are analysed in terms of the constraints parting from energy density, solar-relativistic effects and galactic dynamics along with the dark matter halos.Comment: 26 pages, 3 figures, Minor revision, Published in JHE

Transmission Properties of the oscillating delta-function potential

We derive an exact expression for the transmission amplitude of a particle moving through a harmonically driven delta-function potential by using the method of continued-fractions within the framework of Floquet theory. We prove that the transmission through this potential as a function of the incident energy presents at most two real zeros, that its poles occur at energies $n\hbar\omega+\varepsilon^*$ ($0<Re(\varepsilon^*)<\hbar\omega$), and that the poles and zeros in the transmission amplitude come in pairs with the distance between the zeros and the poles (and their residue) decreasing with increasing energy of the incident particle. We also show the existence of non-resonant "bands" in the transmission amplitude as a function of the strength of the potential and the driving frequency.Comment: 21 pages, 12 figures, 1 tabl