ABSTRACT
Escherichia coli bacterium is a rod-shaped organism composed of a complex double membrane structure. Knowledge of electric field driven ion transport through both membranes and the evolution of their induced permeabilization has important applications in biomedical engineering, delivery of genes and antibacterial agents. However, few studies have been conducted on Gram-negative bacteria in this regard considering the contribution of all ion types. To address this gap in knowledge, we have developed a deterministic and stochastic Brownian dynamics model to simulate in 3D space the motion of ions through pores formed in the plasma membranes of E. coli cells during electroporation. The diffusion coefficient, mobility, and translation time of Ca2+, Mg2+, Na+, K+, and Cl- ions within the pore region are estimated from the numerical model. Calculations of pore's conductance have been validated with experiments conducted at Gustave Roussy. From the simulations, it was found that the main driving force of ionic uptake during the pulse is the one due to the externally applied electric field. The results from this work provide a better understanding of ion transport during electroporation, aiding in the design of electrical pulses for maximizing ion throughput, primarily for application in cancer treatment.
Subject(s)
Electroporation , Escherichia coli , Ion Transport , Biological Transport , Electroporation/methods , IonsABSTRACT
Plants are the source of our understanding of several fundamental biological principles. It is well known that Gregor Mendel discovered the laws of Genetics in peas and that maize was used for the discovery of transposons by Barbara McClintock. Plant models are still useful for the understanding of general key biological concepts. In this article, we will focus on discussing the recent plant studies that have shed new light on the mysterious mechanisms of meiotic crossover (CO) interference, heterochiasmy, obligatory CO, and CO homeostasis. Obligatory CO is necessary for the equilibrated segregation of homologous chromosomes during meiosis. The tight control of the different male and female CO rates (heterochiasmy) enables both the maximization and minimization of genome shuffling. An integrative model can now predict these observed aspects of CO patterning in plants. The mechanism proposed considers the Synaptonemal Complex as a canalizing structure that allows the diffusion of a class I CO limiting factor linearly on synapsed bivalents. The coarsening of this limiting factor along the SC explains the interfering spacing between COs. The model explains the observed coordinated processes between synapsis, CO interference, CO insurance, and CO homeostasis. It also easily explains heterochiasmy just considering the different male and female SC lengths. This mechanism is expected to be conserved in other species.
ABSTRACT
This work investigated the impacts of COVID-19 on pedestrian behavior, answering two research questions using pedestrian push-button data from Utah traffic signals: How did push-button utilization change during the early pandemic, owing to concerns over disease spread through high-touch surfaces? How did the accuracy of pedestrian volume estimation models (developed pre-COVID based on push-button traffic signal data) change during the early pandemic? To answer these questions, we first recorded videos, counted pedestrians, and collected push-button data from traffic signal controllers at 11 intersections in Utah in 2019 and 2020. We then compared changes in push-button presses per pedestrian (to measure utilization), as well as model prediction errors (to measure accuracy), between the two years. Our first hypothesis of decreased push-button utilization was partially supported. The changes in utilization at most (seven) signals were not statistically significant; yet, the aggregate results (using 10 of 11 signals) saw a decrease from 2.1 to 1.5 presses per person. Our second hypothesis of no degradation of model accuracy was supported. There was no statistically significant change in accuracy when aggregating across nine signals, and the models were actually more accurate in 2020 for the other two signals. Overall, we concluded that COVID-19 did not significantly deter people from using push-buttons at most signals in Utah, and that the pedestrian volume estimation methods developed in 2019 probably do not need to be recalibrated to work for COVID conditions. This information may be useful for public health actions, signal operations, and pedestrian planning.
ABSTRACT
ABSTRACT The present review aims to summarize the research carried out in relation to meiosis in birds, especially by observing the protein axes of the chromosomes in prophase I of meiosis. This line of research, initially developed in Argentina, has provided key data in the study of the evolution of sex chromosomes and the mechanisms involved in the frequency and distribution of crossing over in birds, among other topics. Some of these contributions, in addition to those made by other authors, are described also providing the general theoretical framework or the hypotheses that support them.
RESUMEN La presente revisión tiene por objetivo resumir las investigaciones realizadas en relación a la meiosis de las aves, especialmente mediante la observación de los ejes proteicos de los cromosomas en la profase I de la meiosis. Esta línea de investigación, desarrollada inicialmente en Argentina, ha aportado datos clave dentro del estudio de la evolución de los cromosomas sexuales y los mecanismos involucrados en la frecuencia y distribución del crossing over en las aves, entre otros temas. Algunas de estas contribuciones, además de las realizadas por otros autores, se describen proporcionando también el marco teórico general o las hipótesis que las sustentan.
ABSTRACT
Striking an obstacle while walking can be dangerous, reflecting the higher risks of losing one's balance, tripping and falling. Particular situations during which internal resources are limited, such as in a fatigued state, may impair performance when crossing obstacles, enhancing the risks of falls or accidents. Our goal was thus to review the effects of experimentally-induced fatigue (EIF) on gait parameters during obstacle crossing by healthy individuals. We systematically searched PubMed and Web of Science databases using 'fatigue', 'obstacle crossing' and their equivalent terms to extract data from studies investigating this domain. Nine studies were found. First, EIF-related effects on kinetics, EMG and obstacle contacts have been poorly studied. Second, consistent and inconsistent results were found in the kinematic outcomes after EIF. Consistent results included reductions in stride duration and increased step width. Inconsistent results included gait velocity (no-effect vs increased), leading and trailing-foot vertical clearance (reduced vs increased) and horizontal distance from foot to the obstacle before obstacle avoidance (no-effect vs increased). These findings should be interpreted cautiously, however, due to the heterogeneity of the obstacle crossing and EIF protocols.
Subject(s)
Gait , Walking , Humans , Foot , Biomechanical Phenomena , KineticsABSTRACT
La Leucemia Mieloide Aguda es una enfermedad caracterizada por la alteración en la producción de células madre hematopoyéticas y la proliferación celular. Es más común en adultos; a pesar de ello solo se presenta en el 1 % en los Estados Unidos. Entre los 65-68 años se observa una mayor incidencia existiendo de 2-3 casos por cada año en 100.000 habitantes, siendo aproximadamente el 10 % de los cánceres de este tipo. Los diagnósticos más recomendados para esta enfermedad son los de carácter sanguíneo, la realización de citometrías de flujo en muestra de médula ósea. Según estudios, los análisis citogenéticos en un gran número de pacientes han demostrado translocaciones e inversiones en los cromosomas somáticos, mientras que solo una minoría tiene una organización de cromosomas somáticos balanceada. La terapia de consolidación se acompaña del trasplante de células madre hematopoyéticas, conocido como el trasplante alogénico, que puede ser potencialmente curativo en algunos pacientes.
The acute myeloid leukemia, is a disease which is a characterized by an irregular production of hematopoietic cells and cellular proliferation. It´s most common in adults, however only 1% of American adults will be diagnosed throughout their lives. Between the ages of 65-68 there is a high incidence with only 2-3 cases per 100.000 patients; making up only 10% of this type of cancer. It´s mainly diagnosed by using blood test, flow cytometry (on Bone Marrow samples). Some cytogenetic studies suggest that in a significant number of patients both somatic chromosomal inversion and translocation are present, while only a small percentage show no somatic chromosomal mutations. Consolidation therapy with a hematopoietic Stem Cells transplant, also known as a "allogenic transplant", can be potentially curative in some special cases.
Subject(s)
Leukemia, Myeloid , Transplantation, HomologousABSTRACT
O presente trabalho consistiu num estudo de caso dentro de um confinamento comercial, para avaliar o efeito da condição sexual (CS) sobre o desempenho e rendimento de carcaça (RC) no cruzamento Angus x Nelore. Foram registrados dados de 33 lotes com n° de animais/lote variados, ao todo, foram 3049 bovinos (1674 M e 1402 F). Os animais foram apartados por peso e sexo, buscando a homogeneização dos lotes, sendo as fêmeas com peso médio (PM) de 350 kg e os machos de 400 kg. O PM dos bovinos Angus x Nelore apresentaram diferença significativa entre machos e fêmeas durante todas as pesagens, sendo a média de peso maior para os animais machos. A CS se mostrou influente, também, no consumo de matéria seca e no consumo de nutrientes digestíveis totais, onde as fêmeas Angus x Nelore apresentaram médias maiores para ambos os casos, comparados com os machos igualmente confinados. Machos tiveram maiores médias para ganho de peso diário e ganho de peso total por arroba, já para ganho diário de carcaça, as fêmeas apresentaram média superior por Kg/cabeça comparado aos machos. Ao considerar as eficiências produtivas, o estudo apontou diferença significativa apenas para a média de eficiência biológica, onde as fêmeas foram menos eficientes biologicamente em relação a quantidade de dieta usada para produzir uma @ de carcaça, uma vez que consumiram mais e ganharam menos, embora a eficiência alimentar entre os animais machos e fêmeas tenha se mantido indiferente estatisticamente. O RC total foi superior nos machos Angus x Nelore. Contudo, a CS foi um fator influenciador no desempenho e rendimento de carcaça de bovinos cruzados Angus x Nelore dentro do confinamento comercial estudado.
The present work consisted of a case study within a commercial confinement, to evaluate the effect of sexual condition (SC) on carcass performance and yield (CR) in the Angus x Nellore crossing. Data from 33 lots with varied number of animals/lots were recorded, in all, were 3049 cattle. The animals were apart by weight and sex, seeking the homogenization of the lots, being the females with average weight (PM) of 350 kg and males of 400 kg. The PM of Angus x Nellore cattle showed a significant difference between males and females during all weighing´s, with the mean weight higher for male animals. SC was also influential in dry matter intake and total digestible nutrient intake, where Angus x Nellore females presented higher means for both cases, compared with equally confined males. Males had higher averages for daily medium gain (GMD) and total weight gain per art (GPT@) already for daily carcass gain (GDC), females presented higher average per Kg/head compared to males. When considering the productive efficiencies, the study showed a significant difference only for the average biological efficiency, where females were less biologically efficient in relation to the amount of diet used to produce carcass @ since they consumed more and gained less, although feed efficiency between male and female animals remained statistically indifferent. Total CR was higher in Angus x Nelores males. However, SC was an influencing factor in the performance and carcass yield of Angus x Nellore crossed cattle within the commercial feedlot studied.
El presente trabajo consistió en un estudio de caso dentro de un confinamiento comercial, para evaluar el efecto de la condición sexual (CS) sobre el rendimiento y el rendimiento en canal (RC) en el cruce Angus x Nellore. Se registraron datos de 33 lotes con diferente número de animales/lote, en total hubo 3049 bovinos (1674 M y 1402 F). Los animales se separaron por peso y sexo, buscando homogeneizar los lotes, con hembras de 350 kg y machos de 400 kg. El PM del ganado Angus x Nellore mostró una diferencia significativa entre machos y hembras durante todos los pesajes, siendo el peso medio mayor para los machos. CS también influyó en el consumo de materia seca y en el consumo de nutrientes digestibles totales, donde las hembras Angus x Nellore mostraron promedios más altos para ambos casos, en comparación con los machos igualmente confinados. Los machos tuvieron promedios más altos de ganancia promedio diaria y ganancia de peso total por arroba, mientras que para la ganancia diaria de canal, las hembras tuvieron un promedio más alto por kg/cabeza en comparación con los machos. Al considerar las eficiencias productivas, el estudio mostró una diferencia significativa solo para la eficiencia biológica media, donde las hembras fueron menos eficientes biológicamente en relación a la cantidad de dieta utilizada para producir una @ canal, ya que consumieron más y ganaron menos, aunque la eficiencia alimenticia entre animales machos y hembras permaneció estadísticamente indiferente. La RC total fue mayor en los machos Angus x Nellore. Sin embargo, la CS fue un factor que influyó en el rendimiento y rendimiento en canal de los bovinos mestizos Angus x Nellore dentro del confinamiento comercial estudiado.
Subject(s)
Animals , Male , Female , Cattle , Gonadal Steroid Hormones/genetics , Weight Gain/genetics , Sex Factors , Selective Breeding/genetics , Animal Husbandry/methodsABSTRACT
RESUMEN En la producción de carne ovina en Argentina existe escasa tradición para la comercialización de reses de corderos pesados con bajo tenor de grasa. Un nuevo genotipo cuya marca registrada es Magrario (M) fue obtenido en el Campo Villarino de la Facultad de Ciencias Agrarias de la Universidad Nacional de Rosario (33º S, 61º O) por cruzas absorbentes de una raza tradicional en la zona, Ideal (I) (Polwarth), hacia la raza Texel (raza reconocida por producir reses magras). A partir de la población base de la tercera retrocruza se seleccionó a los machos por el Aumento Medio Diario relativo hasta los tres meses de edad y a las hembras por la fertilidad de sus madres. Se verificaron diferencias significativas en la composición de la res en lo referente a depósitos grasos de este nuevo genotipo respecto a la población fundadora I tanto en confinamiento posdestete durante dos meses como en condiciones de cría a campo. También se compararon en confinamiento corderos M con los de la raza Hampshire Down (HD) siendo los depósitos grasos significativamente superiores en esta última raza. También se analizaron cruzamientos de M con HD e I verificando un efecto semi-dominante del nuevo genotipo para reducir tenor de grasa en las cruzas. La reducción de grasa subcutánea en el Longissimus Dorsi de (MxHD) se redujo un 20%. Esta experiencia demostró que Magrario puede ser utilizado como progenitor en cruzamientos si se desea producir corderos con menores depósitos grasos en condiciones de suplementación posdestete.
ABSTRACT Generally there is poor tradition to produce and to commercialize heavy lean lamb carcasses. To achieve a better product for the ovine meat market Ideal (Polwarth) breed ewes were backcrossed to Texel breed rams (breed recognized to reduce carcass fat). Ideal breed (I) is one of the most ordinary breeds in Argentina. However, when their lambs are reared in feedlot conditions, a high fat content is found in their lamb carcasses. After three generations of backcrosses followed by a breeding program for increase male lamb weaning weight and female fertility a new genotype was obtained for the local ovine meat production systems. This new genotype registered as Magrario (M) was obtained at Villarino Field Station of UNR (Zavalla, Santa Fe, 33º S, 61º W). It was verify that M produced more lean meat than I breed under feet lot conditions. M rams were introduced in flocks of Hampshire Down (HD) breed to evaluate lamb crosses with lean meat. Genotype M was compared under feed lot conditions with HD lambs during two months in the post weaning. Also crosses (MxHD), (MxI) and (IxHD) were evaluated in the same conditions. At the end of the experiment ultrasonic methods were used to evaluate fat depot on Longissimus dorsi. The (MxHD) showed a reduction of 20% respecting to HD. These results suggested that M genotype could be a useful paternal genotype to reduce fat depots when the aim is to produce lamb crosses under feed lot conditions in a short period of time.
ABSTRACT
During the first meiotic division, the segregation of homologous chromosomes depends on the physical association of the recombined homologous DNA molecules. The physical tension due to the sites of crossing-overs (COs) is essential for the meiotic spindle to segregate the connected homologous chromosomes to the opposite poles of the cell. This equilibrated partition of homologous chromosomes allows the first meiotic reductional division. Thus, the segregation of homologous chromosomes is dependent on their recombination. In this review, we will detail the recent advances in the knowledge of the mechanisms of recombination and bivalent formation in plants. In plants, the absence of meiotic checkpoints allows observation of subsequent meiotic events in absence of meiotic recombination or defective meiotic chromosomal axis formation such as univalent formation instead of bivalents. Recent discoveries, mainly made in Arabidopsis, rice, and maize, have highlighted the link between the machinery of double-strand break (DSB) formation and elements of the chromosomal axis. We will also discuss the implications of what we know about the mechanisms regulating the number and spacing of COs (obligate CO, CO homeostasis, and interference) in model and crop plants.
ABSTRACT
Absorption and relaxation dynamics of electronic states of free-base, Co(II), Cu(II) and Zn(II) porphyrins bearing a ß-(2,2-difluoro-1,3,2-dioxaborinin-5-yl) group were investigated in dimethyl sulfoxide by using distinct time-resolved spectroscopic techniques. Furthermore, excited state absorption cross-section spectra were determined by combining white light continuum Z-Scan and transient absorption techniques. In the case of the free-base (2H) and Zn(II) porphyrins, we were able to quantify singlet-triplet conversion by analyzing the evolution of time-resolved fluorescence. Relaxation lifetimes from the excited to the ground state were observed in both porphyrins at nanosecond time scale. However, for Co(II) and Cu(II) metalloporphyrins it was observed in the picosecond time scale through femtosecond transient absorption, indicating that both compounds relax back to the ground state only by internal conversion processes. Co(II) and Cu(II) heavy atoms seem to prohibit the radiative and intersystem crossing processes.
ABSTRACT
During meiosis, the number of crossovers vary in correlation to the length of prophase chromosome axes at the synaptonemal complex stage. It has been proposed that the regular spacing of the DNA loops, along with the close relationship of the recombination complexes and the meiotic axes are at the basis of this covariation. Here, we use a cytogenomic approach to investigate the relationship between the synaptonemal complex length and the DNA content in chicken oocytes during the pachytene stage of the first meiotic prophase. The synaptonemal complex to DNA ratios of specific chromosomes and chromosome segments were compared against the recombination rates obtained by MLH1 focus mapping. The present results show variations in the DNA packing ratios of macro- and microbivalents and also between regions within the same bivalent. Chromosome or chromosome regions with higher crossover rates form comparatively longer synaptonemal complexes than expected based on their DNA content. These observations are compatible with the formation of higher number of shorter DNA loops along meiotic axes in regions with higher recombination levels.
Subject(s)
Chromosomes, Mammalian/genetics , Crossing Over, Genetic , DNA/genetics , Meiosis , Oocytes/metabolism , Recombination, Genetic , Synaptonemal Complex , Animals , Chickens , DNA/chemistry , Female , MutL Protein Homolog 1/metabolism , Oocytes/cytologyABSTRACT
Inbreeding, the mating between genetically related individuals, often results in reduced survival and fecundity of offspring, relative to outcrossing. Yet, high inbreeding rates are commonly observed in seaweeds, suggesting compensatory reproductive traits may affect the costs and benefits of the mating system. We experimentally manipulated inbreeding levels in controlled crossing experiments, using gametophytes from 19 populations of Macrocystis pyrifera along its Eastern Pacific coastal distribution (EPC). The objective was to investigate the effects of male-female kinship on female fecundity and fertility, to estimate inbreeding depression in the F1 progeny, and to assess the variability of these effects among different regions and habitats of the EPC. Results revealed that the presence and kinship of males had a significant effect on fecundity and fertility of female gametophytes. Females left alone or in the presence of sibling males express the highest gametophyte size, number, and size of oogonia, suggesting they were able to sense the presence and the identity of their mates before gamete contact. The opposite trend was observed for the production of embryos per female gametes, indicating higher costs of selfing and parthenogenesis than outcrossing on fertility. However, the increased fecundity compensated for the reduced fertility, leading to a stable overall reproductive output. Inbreeding also affected morphological traits of juvenile sporophytes, but not their heatwave tolerance. The male-female kinship effect was stronger in high-latitude populations, suggesting that females from low-latitude marginal populations might have evolved to mate with any male gamete to guarantee reproductive success.
Subject(s)
Macrocystis , Germ Cells, Plant , Inbreeding , ReproductionABSTRACT
The use of supplements eliminates deficiencies imposed by pasture, increases weight gain in animals and maximizes profits from the activity. The objective of this study was to evaluate the performance, carcass traits and meat quality of steers in grazing systems that received or did not receive a protein energy supplement at the level of 0.6 % body weight. The experiment lasted 160 days and included 36 Brangus × Zebu animals. Eighteen animals received supplementation and another eighteen did not receive supplementation. Carcasses were evaluated for yield, loin eye area, fat thickness and length. The assessment of meat quality evaluated the shear force, myofibril fragmentation index, color, exudative losses and collagen. The carcass traits of the supplemented animals showed higher values (p < 0.0001). Supplementation improved the color of the meat (p = 0.0434) and increased the amount of soluble collagen (p = 0.0456). The use of a protein energy supplement for steers in a pasture system increased the efficiency of muscle deposition of these animals and improved meat quality when compared to animals that were not supplemented.
Subject(s)
Animals , Cattle , Red Meat/analysis , Body Composition , Breeding , Food Quality , Dietary SupplementsABSTRACT
Abstract: Roads, despite playing a key role in economy, begin or aggravate processes of forest fragmentation and lead to several species losing their natural habitats, acting as filters and barriers that impose challenges to animal locomotion. Wildlife crossings seek to reestablish the connectivity of the landscape. In general, after being installed, these passages need to be evaluated regarding their functioning. In this study, we present the results of monitoring the underpasses on Serra da Macaca Park Road (SP-139), which crosses Carlos Botelho State Park. The underpasses, constituted by bridges and culverts, were constructed after a license obtained to restore this section of the road. Camera traps were installed inside all crossing structures, and systematic samples were obtained through four field expeditions, with sampling efforts of 10 days each, between March 2018 and February 2019. The footprints found around the intersection structures were also considered. A two-sided Student's t-test was applied to verify differences in richness between the underpasses that have distinct types of margins. Differences in abundance were analyzed through the non-parametric Mann-Whitney test. A Whittaker diagram was generated according to the order of the species, from the most common to the rarest, while their diversity was estimated through Simpson's Diversity Index (1 - D). The Pearson correlation coefficient was used to study the interaction between diversity and altitude variation. We observed a richness of 16 species of terrestrial tetrapods, without any statistically significant differences between underpasses with dry or flooded margins. Cuniculus paca was the most abundant species, and higher altitudes presented the most diversity. We concluded that the underpasses located inside Permanent Preservation Areas (PPAs) of watercourses are essential to maintain the flow of animals beneath the road.
Resumo: As rodovias, apesar de exercerem um papel fundamental na economia, instauram ou agravam processos de fragmentação florestal e levam à perda de habitat. Atuam como filtros e barreiras, dificultando a movimentação animal. As passagens de fauna buscam restabelecer a conectividade na paisagem. Geralmente, após serem implantadas procede-se à avaliação do seu funcionamento. Nesse artigo nós apresentamos os resultados de um monitoramento do uso das passagens inferiores de fauna da Estrada Parque Serra da Macaca (SP-139), que atravessa o Parque Estadual Carlos Botelho. As passagens inferiores, representadas por pontes e galerias hidráulicas, foram concebidas através do licenciamento das obras de revitalização do trecho rodoviário. Armadilhas fotográficas foram instaladas no interior de todas as estruturas, e as amostragens sistemáticas ocorreram por meio de quatro expedições a campo, com um esforço amostral de 10 dias cada, entre março de 2018 e fevereiro de 2019. Os rastros encontrados no perímetro das estruturas de transposição também foram considerados. Os dados foram submetidos ao teste T de Student bicaudal, para verificar a diferença de riqueza entre as passagens inferiores com tipos distintos de margens. As diferenças de abundância foram analisadas pelo teste não paramétrico de Mann-Whitney. O diagrama de Whittaker foi gerado pela ordenação das espécies, a partir das mais comuns para as mais raras, enquanto a diversidade de espécies foi estimada pelo índice de Simpson (1 - D). O coeficiente de correlação de Pearson foi empregado para estudar a interação entre a diversidadade e a variação de altitude. Detectamos uma riqueza de 16 espécies de tetrápodes terrestres e não houve diferença significativa entre as passagens com margens secas e alagadas. Cuniculus paca foi a espécie mais abundante. Altitudes mais elevadas concentraram as maiores diversidades. Concluímos que as passagens inferiores alocadas em APPs de curso d'água são essenciais para manter o fluxo da fauna sob a rodovia.
ABSTRACT
The use of supplements eliminates deficiencies imposed by pasture, increases weight gain in animals and maximizes profits from the activity. The objective of this study was to evaluate the performance, carcass traits and meat quality of steers in grazing systems that received or did not receive a protein energy supplement at the level of 0.6 % body weight. The experiment lasted 160 days and included 36 Brangus × Zebu animals. Eighteen animals received supplementation and another eighteen did not receive supplementation. Carcasses were evaluated for yield, loin eye area, fat thickness and length. The assessment of meat quality evaluated the shear force, myofibril fragmentation index, color, exudative losses and collagen. The carcass traits of the supplemented animals showed higher values (p < 0.0001). Supplementation improved the color of the meat (p = 0.0434) and increased the amount of soluble collagen (p = 0.0456). The use of a protein energy supplement for steers in a pasture system increased the efficiency of muscle deposition of these animals and improved meat quality when compared to animals that were not supplemented.(AU)
Subject(s)
Animals , Cattle , Red Meat/analysis , Food Quality , Dietary Supplements , Breeding , Body CompositionABSTRACT
Resumen Con el fin de obtener información teórica de los efectos genéticos que gobiernan los componentes del rendimiento y poder tener mayor información que permitiera elegir los mejores progenitores para la formación de híbridos con interés comercial, se estimaron los efectos y la capacidad combinatoria general (H.C.G) y específica (H.C.E) en cinco líneas endocríadas de maíz tropical de endospermo amarillo pertenecientes al programa de mejoramiento genético de maíz tropical de la empresa Sem Latam S.A. Se encontró que los efectos de habilidad combinatoria específica para los caracteres relacionados con el componente rendimiento presentaron valores positivos, no obstante, estos no fueron significativamente distintos de cero, lo que se traduce en la no existencia de un patrón heterótico en las líneas evaluadas. De igual modo, las líneas evaluadas presentaron una escasa capitalización de los efectos genéticos no aditivos o dominantes en el proceso de selección genealógica, permitiendo interpretar la baja manifestación de la heterosis como expresión del vigor hibrido de los cruzamientos F1 comparados con los genotipos parentales.
Abstract The general (GCA) and specific (SCA) combining ability and effects of five inbred lines of tropical endosperm maize from Sem Latam SA's tropical maize breeding programme were estimated for obtaining theoretical information concerning the genetic effects governing yield components and to have more information available for selecting the best progenitors for developing and producing commercially interesting hybrids. Positive SCA effect values were found regarding specific combinatorial ability for yield-related characters; however, they were not significantly different from zero, resulting in the lack of a heterotic pattern concerning the lines evaluated here. Little capitalisation regarding such lines' non-additive or dominant genetic effects concerning genealogical selection was seen here, thereby leading to interpreting the low manifestation of heterosis as an expression of the F1 crosses' hybrid vigour compared to that of the parental genotypes.
Resumo Com o objetivo de obter informações teóricas sobre os efeitos genéticos que regem os componentes de desempenho para escolher os melhores genitores de híbridos com interesse comercial, foram estimados os efeitos e a capacidade combinatória geral (HCG) e específica (HCE) em cinco linhagens de endosperma amarelo tropical pertencentes ao programa de melhoramento genético de milho tropical da empresa Sem Latam S.A. Encontrou-se que os efeitos da habilidade combinatória específica para os caracteres relacionados ao componente desempenho apresentaram valores positivos, porém, estes não foram significativamente diferentes de zero, o que se traduz na ausência de um padrão heterótico nas linhas avaliadas. Da mesma forma, as linhagens avaliadas apresentaram pouca capitalização dos efeitos genéticos não aditivos ou dominantes no processo de seleção genealógica, permitindo interpretar a baixa manifestação de heterose como expressão do vigor híbrido dos cruzamentos F1 em comparação com os genótipos parentais.
ABSTRACT
En "El atolondradicho" Lacan insiste en su propósito de desbrozar el estatuto del discurso del psicoanalista. En ese desbroce debería fundarse el lazo social de trabajo que dará cuerpo a la nueva institución analítica por él propuesta, la Escuela. Destaca además que es lazo social sería "limpio de toda necesidad de grupo". Hay implícita en estas afirmaciones lacanianas toda una concepción del agrupamiento y formación de los psicoanalistas. Estas páginas quieren aportar a la elucidación de dicha concepción haciendo foco en el lugar central que en ésta tienen las matemáticas. Se propone que allí se da un atravesamiento de inscripciones políticas, institucionales, epistémicas y clínicas
In "L' Étourdit" Lacan insists on his intention of clearing up the status of the psychoanalyst´s discourse. In this clearing, the social bond that will give shape to the new analytical institution proposed by him, the School, should be founded. He also emphasizes that this social bond would be "clean of all group needness". Implicit in these Lacanian statements is a whole conception of the grouping and formation of psychoanalysts. These pages want to contribute to the elucidation of this conception by focusing on the central place that mathematics has in it. The aim is to give an account of how the mathematical formalization crosses, at the same time, the School´s political-institutional proposal and the conceptualization of the clinical experience. It is proposed that there is a crossing of political, institutional, epistemic and clinical inscriptions