11,196 research outputs found
Ensuring successful introduction of Wolbachia in natural populations of Aedes aegypti by means of feedback control
The control of the spread of dengue fever by introduction of the
intracellular parasitic bacterium Wolbachia in populations of the vector Aedes
aegypti, is presently one of the most promising tools for eliminating dengue,
in the absence of an efficient vaccine. The success of this operation requires
locally careful planning to determine the adequate number of individuals
carrying the Wolbachia parasite that need to be introduced into the natural
population. The introduced mosquitoes are expected to eventually replace the
Wolbachia-free population and guarantee permanent protection against the
transmission of dengue to human.
In this study, we propose and analyze a model describing the fundamental
aspects of the competition between mosquitoes carrying Wolbachia and mosquitoes
free of the parasite. We then use feedback control techniques to devise an
introduction protocol which is proved to guarantee that the population
converges to a stable equilibrium where the totality of mosquitoes carry
Wolbachia.Comment: 24 pages, 5 figure
Photometry of VS0329+1250: A New, Short-Period SU Ursae Majoris Star
Time-resolved CCD photometry is presented of the recently-discovered (V~15 at
maximum light) eruptive variable star in Taurus, which we dub VS0329+1250. A
total of ~20 hr of data obtained over six nights reveals superhumps in the
light curves, confirming the star as a member of the SU UMa class of dwarf
novae. The superhumps recur with a mean period of 0.053394(7) days (76.89 min),
which represents the shortest superhump period known in a classical SU UMa
star. A quadratic fit to the timings of superhump maxima reveals that the
superhump period was increasing at a rate given by dP/dt ~ (2.1 +/- 0.8) x
10^{-5} over the course of our observations. An empirical relation between
orbital period and the absolute visual magnitude of dwarf novae at maximum
light, suggests that VS0329+1250 lies at a distance of ~1.2 +/- 0.2 kpc.Comment: V2 - The paper has been modified to incorporate the referee's
comments, and has now been accepted for publication in the PASP. The most
significant change is that we are now able to confirm that the superhump
period was increasing during the course of our observation
Estimativa da umidade de um latossolo vermelho-amarelo distrófico com uso da técnica da TDR.
O acompanhamento da umidade do solo com o uso da reflectomentria do domÃnio do tempo (TDR) vem sendo cada vez mais utilizada para o monitoramento da umidade do solo, devido à facilidade de operação e determinação de umidade do solo em tempo real. O presente trabalho teve como objetivo avaliar a estimativa da umidade de um Latossolo Vermelho-Amarelo Distrófico com uso da técnica da reflectomentria do domÃnio do tempo (TDR). Foram Utilizadas amostras de solo indeformadas, retiradas nas camadas de 0,5-0,20; 0,25 - 0,40; 0,45 - 0,60 e 0,65 - 0,80 m, sendo três repetições para cada camada do solo, totalizando 12 amostras. As sondas de TDR foram confeccionadas artesanalmente, com três hastes de 0,003 m de diâmetro e 0,10 m de comprimento efetivo, fora da resina, espaçadas de 0,017 m com cabos coaxiais de 50 ohms e isoladas com resina epóxi no inicio das hastes. As amostras foram retiradas com tubo de PVC de 0,15 m de comprimento por 0,110 m de diâmetro nominal. As leituras do peso do conjunto tubo - sonda - solo - tela - papel foi feita com balança analÃtica e a umidade do solo estimada pela TDR. As estimativas para as diferentes camadas do solo não apresentaram diferenças entre si. O ajuste do modelo avaliza a calibração para as camadas do solo em estudo, indicando a viabilidade do emprego das sondas manufaturadas
Influência de época de plantio no rendimento de quatro cultivares de milho irrigado, na região norte do Estado de Minas Gerais.
Ages, metallicities and -element enhancement for galaxies in Hickson compact groups
Central velocity dispersions and eight line-strength Lick indices have been
determined from 1.3 resolution long-slit spectra of 16 elliptical
galaxies in Hickson compact groups. These data were used to determine galaxy
properties (ages, metallicities and -element enhancements) and allowed
a comparison with the parameters determined for a sample of galaxies in lower
density environments, studied by Gonz\'alez (1993). The stellar population
parameters were derived by comparison to single stellar population models of
Thomas et al. (2003) and to a new set of SSP models for the indices Mg,
Fe5270 and Fe5335 based on synthetic spetra. These models, based on an update
version of the fitting functions presented in Barbuy et al. (2003), are fully
described here. Our main results are: (1) the two samples have similar mean
values for the metallicities and [/Fe] ratios, (2) the majority of the
galaxies in compact groups seem to be old (median age of 14 Gyr for eight
galaxies for which ages could be derived), in agreement with recent work by
Proctor et al. (2004). These findings support two possible scenarios: compact
groups are either young systems whose members have recently assembled and had
not enough time to experience any merging yet or, instead, they are old systems
that have avoided merging since their time of formation.Comment: Accepted for publication in A
Efeito de antÃdotos na atividade das cloroacetanilidas sobre as plantas de sorgo (Sorghum bicolor (L.) Moench.
Foram conduzidos dois experimentos, no ano agricola 1983/84, objetivando estudar a eficiencia dos antidotos CGA 92194 CGA 43089 sobre a tolerancia dos cultivares de sorgo BR 300 (granifero) e BR 501 (sacarino) as cloroacetanilidas e ao atrazine, bem como os respectivos efeitos desses herbicidas sobre a s plantas daninhas. O solo do local escolhido para a instalacao dos ensaios, em 1983/84, foi um Latossolo Vermelho-Escuro, fase cerrado, com textura argilosa e materia organica entre 2,57 e 2,90%. O delineamento experimental foi em blocos ao acaso, em esquema fatorial completo, com quatro repeticoes. Os tratamentos foram: atrazine a 1,5 kg/ha, aplicado isoladamente e em mistura com metolachlor, alachlor, acetochlor e propachlor, com e sem antidoto, mais uma testemunha, sem herbicida, capinada e sem capina. Os antidotos foram aplicados na forma de tratamento de sementes. As caracteristicas avaliadas foram: stand, inicial e final, altura de plantas, numero de paniculas, peso de paniculas, producao de graos, densidade de plantas daninhas e peso da materia seca da parte aerea aos 34 e 64 dias apos a aplicacao dos produtos. Para o sorgo sacarino, alem dessas caracteristicas, avaliaram-se ainda o peso da massa verde total da parte aerea, o peso total dos colmos despalhados, o diametro do colmo despalhado, a percentagem de caldo extraido, acucares redutores, acucares redutores totais, sacarose total sacarose e brix, determinados segundo metodo proprio do CNPMS, Sete Lagoas, MG
Coulomb and quantum oscillator problems in conical spaces with arbitrary dimensions
The Schr\"odinger equations for the Coulomb and the Harmonic oscillator
potentials are solved in the cosmic-string conical space-time. The spherical
harmonics with angular deficit are introduced.
The algebraic construction of the harmonic oscillator eigenfunctions is
performed through the introduction of non-local ladder operators. By exploiting
the hidden symmetry of the two-dimensional harmonic oscillator the eigenvalues
for the angular momentum operators in three dimensions are reproduced.
A generalization for N-dimensions is performed for both Coulomb and harmonic
oscillator problems in angular deficit space-times.
It is thus established the connection among the states and energies of both
problems in these topologically non-trivial space-times.Comment: 15 page
Using a Cournot-Nash model to study the contributions of cooperation for fishing stocks recover and for fishers' rents
In our study we implement a model to explain the recover of stocks of a common resource pool in the fisheries area. Our aim is to model the behavior of two Fishing Companies through a model supported in Cournot model and in Nash principles of equilibrium. Our Cournot-Nash model is supported in the competing behavior of agents. Afterwards, we present an adjusted model to study the results of cooperation between agents. We can see that cooperation brings up procedures that allow conservation of species and stocks recover. We conclude that agents' cooperation brings the possibility to get good results for species preservation and good rents for fishers.info:eu-repo/semantics/publishedVersio
Crescimento da bananeira prata anã sob diferentes sistemas de irrigação em condições de agricultura familiar no Semiárido.
Os assentamentos ribeirinhos localizados no semi-árido não possuem infra-estrutura para irrigação, o que impede o desenvolvimento dessas comunidades essencialmente agrÃcolas. É necessário nessas condições uso de sistemas de irrigação de baixo custo acessÃveis a esses agricultores. O trabalho objetivou avaliar três sistemas de irrigação em área plantada com bananeira cultivar Prata Anã no espaçamento de 3,0 x 2,5m, em um assentamento no semi-árido da Bahia. Adotou-se o delineamento experimental em blocos ao acaso, com quatro repetições, em esquema em parcelas subdivididas, sendo dois perÃodos de crescimento (crescimento vegetativo e emissão floral) e três sistemas de irrigação (S1-bacia alimentada por canal revestido, S2- microaspersão adaptada e S3-gotejamento adaptado). Foram avaliadas as variáveis, altura de planta, diâmetro do caule e área foliar. Os sistemas propostos para agricultura familiar tiveram efeito sobre todas as variáveis, entretanto não houve diferença entre as médias para altura e área foliar no perÃodo de crescimento vegetativo e após a emissão floral. O sistema S1 foi o que apresentou maiores médias absolutas das variáveis de crescimento analisadas durante as duas avaliações realizadas
Arabic version of the Personality Inventory for the DSM-5 (PID-5) in a community sample of United Arab Emirates nationals
Background: Section III of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) proposes a model for conceptualizing personality disorders in which they are characterized by impairments in personality functioning and maladaptive personality traits. The Personality Inventory for DSM-5 (PID-5) is a self-report measure that assesses the presence and severity of these maladaptive personality traits. Objective: The current study examined the reliability and validity of the Arabic version of the Personality Inventory for DSM-5 (PID-5) to measure maladaptive personality traits in the Emirati population of the United Arab Emirates. Methods: The Arabic version of the PID-5 was administered to a community sample of 1,090 United Arab Emirates nationals (89.5% female and 10.5% male, mean age = 22.44 years old). The descriptive measures, internal consistency, test-retest reliability, convergent validity with NEO – Five Factor Inventory, as well as PID-5’s factor structure, were all addressed. Results: The PID-5facets and domains mean scores were higher in the Emirati sample compared to the original US sample. Internal consistency of the PID-5 scales was acceptable to high and test-retest coefficients ranged from 0.84 (facets) to 0.87 (domains). As expected, the five domains of the Arabic version of the PID-5 correlated significantly with all Five-Factor Model domains of personality. Additionally, the Arabic version of the PID-5 confirmed a five-factor structure that resembles the PID-5 domains. Conclusion: The findings of this study provided initial support for the use of the Arabic version of the PID-5 to assess maladaptive personality traits in the Emirati population of the United Arab Emirates.info:eu-repo/semantics/publishedVersio
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