Management of investment portfolios employing reinforcement learning.

Investors are presented with a multitude of options and markets for pursuing higher returns, a task that often proves complex and challenging. This study examines the effectiveness of reinforcement learning (RL) algorithms in optimizing investment portfolios, comparing their performance with traditional strategies and benchmarking against American and Brazilian indices. Additionally, it was explore the impact of incorporating commodity derivatives into portfolios and the associated transaction costs. The results indicate that the inclusion of derivatives can significantly enhance portfolio performance while reducing volatility, presenting an attractive opportunity for investors. RL techniques also demonstrate superior effectiveness in portfolio optimization, resulting in an average increase of 12% in returns without a commensurate increase in risk. Consequently, this research makes a substantial contribution to the field of finance. It not only sheds light on the application of RL but also provides valuable insights for academia. Furthermore, it challenges conventional notions of market efficiency and modern portfolio theory, offering practical implications. It suggests that data-driven investment management holds the potential to enhance efficiency, mitigate conflicts of interest, and reduce biased decision-making, thereby transforming the landscape of financial investment.

A computerized method for evaluating scoliotic deformities using elliptical pattern recognition in X-ray spine images.

BACKGROUND AND OBJECTIVE: Several studies have evaluated the reproducibility of the Cobb angle for measuring the degree of scoliotic deformities from X-ray spine images, and proposed different geometric models for describing the spinal curvature. The ellipse was shown to be an adequate geometric form, but was not yet applied for the identification and quantification of scoliotic curvatures. The purpose of this study is therefore to propose and validate a novel computerized methodology for the detection of elliptical patterns from X-ray images to evaluate the extent of the underlying scoliotic deformity. METHODS: For anteroposterior each X-ray spine image, the spine curve is first reconstructed from vertebral centroids. The ellipse that best fits to the obtained spine curve is the found within a least square and genetic algorithm optimization framework. The geometric parameters of the resulting best fit ellipse are finally used to define an index that quantifies the spinal curvature. RESULTS: The proposed methodology was validated on three synthetic images and then successfully applied to 20 clinical anteroposterior X-ray spine images of patients with a different degree of scoliotic deformity, with the resulting maximal relative error of 3% for the synthetic images and an overall error of 0.5 ±â€¯0.4 mm (mean ±â€¯standard deviation) for the clinical cases. CONCLUSIONS: The results indicate that the proposed computerized methodology is able to reliably reproduce scoliotic curvatures using the geometric parameters of the underlying ellipses. In comparison to conventional approaches, the proposed methodology potentially produces less errors, requires a relatively low observer interaction, takes into account all vertebrae within the observed scoliotic deformity, and allows for both qualitative and quantitative evaluations that may complement the diagnosis, study and treatment of scoliosis.

Oral receptivity of Aedes aegypti from Cape Verde for yellow fever, dengue, and chikungunya viruses.

At the end of 2009, 21,313 cases of dengue-3 virus (DENV-3) were reported in the islands of Cape Verde, an archipelago located in the Atlantic Ocean 570 km from the coast of western Africa. It was the first dengue outbreak ever reported in Cape Verde. Mosquitoes collected in July 2010 in the city of Praia, on the island of Santiago, were identified morphologically as Aedes aegypti formosus. Using experimental oral infections, we found that this vector showed a moderate ability to transmit the epidemic dengue-3 virus, but was highly susceptible to chikungunya and yellow fever viruses.

The use of transport and diffusion equations in the three-dimensional reconstruction of computerized tomographic images / O uso de equações de transporte e difusão na reconstrução de imagens de tomografia computadorizada em três dimensões

The visualization of a computerized tomographic (TC) exam in 3D increases the quality of the medical diagnosis and, consequently, the success probability in the treatment. To obtain a high quality image it is necessary to obtain slices which are close to one another. Motivated towards the goal of reaching an improved balance between quantity of slices and visualization quality, this research work presents a digital inpainting technique of 3D interpolation for CT slices used in the visualization of human body structures. The inpainting is carried out via non-linear partial differential equations (PDE). The PDE's have been used, in the image-processing context to fill in the damaged regions in a digital 2D image. Inspired by this idea, this article proposes an interpolation method for the filling in of the empty regions between the CT slices. To do it, considering the high similarity between two consecutive real slice, the first step of the proposed method is to create the virtual slices. The virtual slices contain all similarity between the intercaleted slices and, when there aren't similarities between real slices, the virtual slices will contain indefinite portions. In the second step of the proposed method, the created virtual slices will be used together with the real slices images, in the reconstruction of the structure in three dimensions, mapped onto the exam. The proposed method is capable of reconstructing the curvatures of the patient's internal structures without using slices that are close to one another. The experiments carried out show the proposed method's efficiency.

A visualização do resultado de uma tomografia computadorizada (CT) em 3D aumenta a qualidade do diagnóstico médico e, consequentemente, a probabilidade de sucesso no tratamento. Para obter uma maior qualidade na imagem 3D, é necessário obter fatias próximas umas das outras. Motivados pela meta de obter um apropriado balanceamento entre a quantidade de fatias e a qualidade da visualização, este trabalho apresenta uma técnica de retoque digital por interpolação 3D para fatias de CT usadas na visualização de estruturas do corpo humano. O retoque digital é feito através de equações diferenciais parciais não lineares (EDP). As EDPs têm sido utilizadas no contexto de processamento de imagens para preencher regiões defeituosas de imagens em 2D. Inspirado por esta ideia, este artigo propõe um método de interpolação para preencher as regiões vazias entre as fatias de TC. Para isto, considera-se a grande semelhança entre duas fatias reais consecutivas, onde o primeiro passo do método proposto é a criação de fatias virtuais. As fatias virtuais contêm todas as regiões similares entre as duas fatias intercaladas, sendo que onde não há semelhança entre as fatias reais, as fatias virtuais conterão regiões indefinidas. No segundo passo do método proposto, as fatias virtuais criadas serão utilizadas junto com as fatias reais para a reconstrução da estrutura em três dimensões, mapeadas no exame. O método é capaz de reconstruir as curvaturas das estruturas internas do paciente sem a necessidade de utilizar fatias muito próximas uma das outras. Os experimentos realizados mostram a eficiência do método proposto.

Preferência alimentar e desempenho de Brontocoris tabidus Signoret (Hemiptera, Pentatomidae) em plantas hospedeiras / Feeding preference and performance of Brontocoris tabidus (Signoret) (Hemiptera, Pentatomidae) among host plants

O comportamento de escolha entre plantas pelo percevejo predador Brontocoris tabidus (Signoret) (Hemiptera, Pentatomidae) e a relação com o ganho de peso e seu desempenho foram investigados com plantas de algodoeiro, Gossypium hirsutum L. (Malvaceae), caruru, Amaranthus lividus L. (Amaranthaceae) e feijão, Phaseolus vulgaris L. (Fabaceae). Adultos do predador foram permitidos livre escolha entre plantas e, posteriormente, mantidos sobre as mesmas plantas escolhidas inicialmente para a alimentação. Também, o desenvolvimento e a reprodução foram obtidos confinando os predadores com e sem presa mais plantas. Os resultados mostraram que B. tabidus não demonstrou preferência para alimentação entre as plantas estudadas. O tempo de alimentação (106 a 115 minutos) e ganho de peso (28 a 30 por cento do peso vivo) foram similares em relação à alimentação em plantas. Entretanto, a longevidade das fêmeas foi menor quando mantidas em feijão, comparadas com algodoeiro e caruru. A duração da fase ninfal do predador variou entre as plantas, bem como a produção de descendentes demonstrando menor desempenho sobre plantas de feijão. As ninfas alimentadas, apenas, de plantas não atingiram a fase adulta e viveram até 6,5 dias, sendo maior a sobrevivência em algodoeiro e caruru. Os resultados mostram que apesar de B. tabidus não apresentar seleção da planta hospedeira para alimentação, estas podem contribuir diferentemente na sua história de vida com destaque para o algodão e o caruru entre as plantas estudadas.

The choice between cotton, Gossypium hirsutum L. (Malvaceae), green bean, Phaseolus vulgaris L. (Fabaceae) and pigweed, Amaranthus lividus L. (Amaranthaceae) and its relationship as first feeding, weight gain and biological performance of the predator Brontocoris tabidus (Signoret) (Hemiptera, Pentatomidae) adults were studied. Adults of the predator were allowed to choose between plants and, immediately paired and reared on the same selected plants plus prey. Furthermore, nymphal development and adult stage were obtained on the same plants plus prey. The results show that B. tabidus do not exhibit host plant preference among tested plants. Likewise, feeding period (106 to 115 minutes) and weight gain (28 to 30 percent of body weight) were statistically equal among plants. However, predators at adult stage only or nymphal and adult stages maintained on young green bean plants plus prey exhibited lower performance compared to the other plants. Nymphs feeding exclusively on plants lived, on average, up to 6.5 days but did not reach adult stage and lived longer on cotton plants and pig weed. The results indicated that adults of the predator B. tabidus do not exhibit selection on host plant to feed although different results in its life history was attained among the studied plants with better results for cotton and pigweed.

[Ultrastructure of the ovarioles of Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) submitted to three photoperiods]. / Ultra-estrutura dos ovaríolos de Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) submetido a três fotoperíodos.

The research evaluated the ultrastructure of the ovarioles of Tropidacris collaris (Stoll), submitted to photoperiods 10L:14D, 12L:12D and 14L:10D. Sixty nymphs (30 males and 30 females) in the last stage of development were paired in ten couples in each treatment. Thirty days after adult emergence, the females were immobilized with ethylic ether and dissected under stereomicroscope. The ovarioles were transferred to Karnovsky fixative (2.5% glutaraldehyde, 4% paraformaldehyde and 0.1 M sodium cacodylate buffer) and analyzed in transmission and scanning electron microscopes. The different photoperiods had no effect on the ovarioles' ultrastructure. Each ovariole is covered by a thick sheath constituted by a homogeneous and filamentous material. In the terminal filament, there are cells with large nuclei, some with scarce cytoplasm and projections cytoplasmatic, besides filamentous structures assuming characteristic of conjunctive tissue. In the germarium, the germ cells are big with large nuclei, scarce cytoplasm and plasma membrane containing interdigitations. The follicular cells are small with a small nucleus, yet presenting cytoplasmatic projections. In the vitellarium the follicular cells suffer modifications in their morphology varying from cubic to flat.

Ultra-estrutura dos ovaríolos de Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) submetido a três fotoperíodos / Ultrastructure of the ovarioles of Tropidacris collaris (Stoll) (Orthoptera: Romaleidae) submitted to three photoperiods

A pesquisa teve o objetivo de avaliar a ultra-estrutura dos ovaríolos de Tropidacris collaris (Stoll), submetido aos fotoperíodos de 10L:14E, 12L:12E e 14L:10E. Foram utilizadas 60 ninfas (30 machos e 30 fêmeas) no último estágio de desenvolvimento, sendo colocados 10 casais em cada tratamento. Trinta dias após atingirem o estágio adulto, as fêmeas foram sedadas com éter etílico e dissecadas sob estereomicroscópio. Os ovaríolos foram fixados em Karnovsky (glutaraldeido 2,5 por cento, paraformaldeído 4 por cento e tampão cacodilato de sódio 0,1 M) e analisados em microscopia eletrônica de transmissão e varredura. Os resultados mostraram não haver influência dos fotoperíodos sobre a ultra-estrutura dos ovaríolos, onde estes apresentaram-se revestidos por uma bainha espessa constituída por um material homogêneo e filamentoso. Na região do filamento terminal observaram-se células com núcleos volumosos, algumas com citoplasma escasso, além de estruturas filamentosas assumindo característica de tecido conjuntivo. No germário, as células germinativas são maiores, com núcleos volumosos, escassos citoplasma e membrana celular com interdigitações. As células foliculares são menores com núcleo pequeno, apresentando ainda projeções citoplasmáticas. No vitelário as células foliculares sofrem modificações na sua morfologia, variando de cúbica a achatada.

The research evaluated the ultrastructure of the ovarioles of Tropidacris collaris (Stoll), submitted to photoperiods 10L:14D, 12L:12D and 14L:10D. Sixty nymphs (30 males and 30 females) in the last stage of development were paired in ten couples in each treatment. Thirty days after adult emergence, the females were immobilized with ethylic ether and dissected under stereomicroscope. The ovarioles were transferred to Karnovsky fixative (2.5 percent glutaraldehyde, 4 percent paraformaldehyde and 0.1 M sodium cacodylate buffer) and analyzed in transmission and scanning electron microscopes. The different photoperiods had no effect on the ovarioles' ultrastructure. Each ovariole is covered by a thick sheath constituted by a homogeneous and filamentous material. In the terminal filament, there are cells with large nuclei, some with scarce cytoplasm and projections cytoplasmatic, besides filamentous structures assuming characteristic of conjunctive tissue. In the germarium, the germ cells are big with large nuclei, scarce cytoplasm and plasma membrane containing interdigitations. The follicular cells are small with a small nucleus, yet presenting cytoplasmatic projections. In the vitellarium the follicular cells suffer modifications in their morphology varying from cubic to flat.

Patogenicidade de Metarhizium anisopliae var. anisopliae e Metarhizium anisopliae var. acridum sobre Nasutitermes coxipoensis (Holmgren) (Isoptera: Termitidae) / Pathogenicity of Metarhizium anisopliae var. anisopliae and Metarhizium anisopliae var. acridum on Nasustitermes coxipoensis (Holmgren) (Isoptera: Termitidae)

A ação de Metarhizium anisopliae var. anisopliae e Metarhizium anisopliae var. acridum sobre o cupim de montículo Nasutitermes coxipoensis (Holmgren) e a produção de conídios sobre os insetos mortos foram estudadas em laboratório. Doses infectivas foram determinadas através do contato direto dos insetos com a cultura fúngica após 12 dias de crescimento e quantificação dos conídios em câmara de Neübauer. Foram utilizadas as doses 0,5 x 10(6) e 1,6 x 10(7) conídos/ml, para M. anisopliae var. anisopliae, e 1,4 x 10(5) e 1,8 x 10(6) conídios/ml para M. anisopliae var. acridum, nominadas dose A e dose B, respectivamente. As doses corresponderam a 3 min. e 15 min. de contato direto de 20 cupins com a cultura fúngica. A produção de conídios foi avaliada utilizando-se insetos inoculados com o fungo, 10 dias após a morte. Os bioensaios foram realizados em triplicata. Os percentuais de mortalidade acumulada de N. coxipoensis tratados com M. anisopliae, no terceiro dia após a inoculação, foram: controle, 15,7 por cento; dose A 95,7 por cento e dose B 100 por cento; para M. anisopliae var. acridum foram: controle, 13,3 por cento; dose A 66,4 e dose B 88,8 por cento. A média da produção de conídios foi mais elevada para M. anisopliae var. anisopliae do que para M. anisopliae var. acridum. Os resultados mostraram que M. anisopliae var. anisopliae apresentou maior potencial para o controle biológico de N. coxipoensis.

The action of Metarhizium anisopliae var. anisopliae and Metarhizium anisopliae var. acridum on the mound termite Nasutitermes coxipoensis (Holmgren) and the conidia production on dead insects were studied in laboratory. Infective doses were determined through direct contact of the insects with the fungi cultures with 12 days of growth followed by conidia quantification in Neübauer camera. The doses of 0.5 x 10(6) and 1.6 x 10(7) conidia/ml of M. anisopliae var. anisopliae, and 1.4 x 10(5) e 1.8 x 10(6) conidia/ml of M. anisopliae var. acridum were named dose A and dose B, for each fungus, respectively. These doses corresponded to 3-min and 15-min direct contact of 20 insects with the fungi cultures. Conidia production was evaluated using the insects inoculated with fungi. The bioassays were carried out in triplicate. The percentage of accumulated mortality of N. coxipoensis treated with M. anisopliae var. anisopliae on the third day after inoculation were: control, 15.7 percent; dose A 95.7 percent and dose B 100 percent; for M. anisopliae var. acridum: control, 13.3 percent; dose A 66.4 percent and dose B 88,8 percent. The average of conidia production was higher for M. anisopliae var. anisopliae than M.anisopliae var. acridum. The results showed that M. anisopliae var. anisopliae presented better potential for the biological control of N. coxipoensis.

Mecanismos de ação de himenópteros parasitóides sobre Megastes spp. (Lepidoptera: Pyralidae) em agroecossistema de batata-doce (Ipomoea batatas L.) / Attack of parasitoids himenoptera on Megastes spp. (Lepidoptera: Pyralidae) in sweet potato agroecossystem

Estudaram-se a presença e a ação de himenópteros parasitóides em agroecossistema de batata-doce (Ipomoea batatas L.) no município de Pedra de Fogo - PB, sobre o complexo Megastes spp, com o objetivo de identificar as espécies de parasitóides existentes, bem como descrever os principais eventos na ação de parasitismo sobre Megastes grandalis Guenee e Megastes pusialis Snellen. No levantamento direto, em 14 por cento das plantas, existiam fêmeas de microhimenópteros ectoparasitóides da família braconidae atacando lagartas de Megastes spp. No levantamento indireto, constatou-se um ataque de parasitóide em 22 por cento das lagartas, emergindo adultos de sete espécies das famílias braconidae, Chalcididae e Ichneumonidae, com predominância de braconídeos ectoparasitóides. Concluiu-se que a presença de parasitóides no agroecossistema da batata-doce é bastante diversificada e proporcionam uma boa contribuição na mortalidade natural da praga.

[Population growth rate of the depredating Podisus nigrispinus (Heteroptera: Pentatomidae) and of the Tuta absoluta (Leptoptera: gelechiidae) in wintering place]. / Tasa de crecimiento poblacional del chinche depredador Podisus nigrispinus (Heteroptera: Pentatomidae) y de la presa Tuta absoluta (Lepidoptera: Gelechiidae) en invernadero.

The fertility life table of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) preying either on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) caterpillars or on alternative prey Tenebrio molitor L. (Coleoptera: Tenebrionidae) under greenhouse conditions (30 +/- 5 degrees C, 61 +/- 23% RH) were studied. The life table was also determined for the pest T. absoluta under the same conditions. The net reproductive rate (Ro) and the intrinsic rate of natural increase (rm) were higher 14.13 and 46.32 times for predators fed on T. molitor prey, however, the generation time (T) was similar between prey. The pest T. absoluta showed Ro and rm higher 2.15 and 32.10 times than those achieved for predators fed on this pest. However, females fed on a suitable prey T. molitor showed higher Ro and rm than those yielded for the pest. The survival curves were similar for P. nigrispinus females fed on both prey and classified as being type II by Weibull analysis. The results suggest that P. nigrispinus is able to maintain its population preying only on T. absoluta caterpillars; however, the life table parameters determined individually for both showed that the pest produces more generations per year and faster population natural growth than the predator.

Tasa de crecimiento poblacional del chinche depredador Podisus nigrispinus (Heteroptera: Pentatomidae) y de la presa Tuta absoluta (Lepidoptera: Gelechiidae) en invernadero / Population growth rate of the depredating Podisus nigrispinus (Heteroptera: Pentatomidae) and of the Tuta absoluta (Leptoptera: gelechiidae) in wintering place

The fertility life table of Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) preying either on Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) caterpillars or on alternative prey Tenebrio molitor L. (Coleoptera: Tenebrionidae) under greenhouse conditions (30 +/- 5 degrees C, 61 +/- 23 RH) were studied. The life table was also determined for the pest T. absoluta under the same conditions. The net reproductive rate (Ro) and the intrinsic rate of natural increase (rm) were higher 14.13 and 46.32 times for predators fed on T. molitor prey, however, the generation time (T) was similar between prey. The pest T. absoluta showed Ro and rm higher 2.15 and 32.10 times than those achieved for predators fed on this pest. However, females fed on a suitable prey T. molitor showed higher Ro and rm than those yielded for the pest. The survival curves were similar for P. nigrispinus females fed on both prey and classified as being type II by Weibull analysis. The results suggest that P. nigrispinus is able to maintain its population preying only on T. absoluta caterpillars; however, the life table parameters determined individually for both showed that the pest produces more generations per year and faster population natural growth than the predator.