Importance of canopy porosity into vineyard and the relationship with the grape maturity. Digital estimation method

In warm and dry climates, the use of porous systems should be required in order to allow a better leaf distribution inside the plant, causing more space in the clusters area and enhancing determined physiological processes so in the leaf (photosynthesis, ventilation, transpiration) as in berry (growth and maturation). Plant geometry indexes, yield and must composition have been studied in three different systems: sprawl with 12 shoots/m (S1); sprawl system with 18 shoots/m (S2) and vertical positioned system or VSP with 12 shoots/m (VSP1). Total leaf area increases as the crop load does, whoever surface area depends on to two factors: crop load and the training system (VSP vs . sprawl), which can provide differences in leaf exposure efficiencies. The main objective of this study was to validate digital photography measurements used to compare porosity differences among treatments and, as they affect plant microclimate and, therefore, yield and berry quality. Also, all previous studied indexes (LAI, SA, SFEr) tended to overestimate the relationship between exposed leaf surface and porosity of each treatment, but the use of digital method proved to be an effective tool in order to assess canopy porosity. Results showed that not positioned and free systems (sprawl) scored between 25 - 50% more porosity in the clusters area than the fixed vertical system (VSP), which resulted in a better plant microclimate for test conditions, mainly by improving the exposure of internal clusters and internal canopy ventilation. On the other hand, higher crop load treatment (S2) showed a real increase in yield (16%) without any relevant change into must composition, even improving total anthocyanin content into berry during ripening

Iron distribution through the developmental stages of Medicago truncatula nodules.

Paramount to symbiotic nitrogen fixation (SNF) is the synthesis of a number of metalloenzymes that use iron as a critical component of their catalytical core. Since this process is carried out by endosymbiotic rhizobia living in legume root nodules, the mechanisms involved in iron delivery to the rhizobia-containing cells are critical for SNF. In order to gain insight into iron transport to the nodule, we have used synchrotron-based X-ray fluorescence to determine the spatio-temporal distribution of this metal in nodules of the legume Medicago truncatula with hitherto unattained sensitivity and resolution. The data support a model in which iron is released from the vasculature into the apoplast of the infection/differentiation zone of the nodule (zone II). The infected cell subsequently takes up this apoplastic iron and delivers it to the symbiosome and the secretory system to synthesize ferroproteins. Upon senescence, iron is relocated to the vasculature to be reused by the shoot. These observations highlight the important role of yet to be discovered metal transporters in iron compartmentalization in the nodule and in the recovery of an essential and scarce nutrient for flowering and seed production.

Effects of irrigation and time of application on the yield and quality of cv. Cabernet sauvignon in a warm climate

Mediterranean climate is characterized by hot summer, high evapotranspiration rates, and scarce precipitations (400 mm per year) during grapevine cycle. These extremely dry conditions affect vineyard productivity and sustainability. Supplementary irrigation is a needed practice in order to maintain yield and quality. Almost all Spanish grape growing regions are characterized by these within this context, especially in the center region, where this study was performed. The main objective of this work was to study the influence of irrigation on yield and quality. For this aim, we applied different levels of irrigation (mm of water applied) during different stages of growth and berry maturity. Four experimental treatments were applied considering the amount of water and the moment of the application: T1: Water irrigation (420 mm) applied from bloom to maturity. T2: Corresponded to the traditional irrigation scheduling, from preveraison to maturity (154 mm). T3: Water irrigation from bloom to preveraison, and water deficit from veraison to maturity (312 mm). T4: Irrigation applied from preveraison to maturity (230 mm) Experimental vineyard, cv. Cabernet Sauvignon, was located in a commercial vineyard (Bodegas Licinia S.L.) in the hot region of Morata de Tajuña (Madrid). The trial was performed during 2010 and 2011 seasons. Our results showed that yield increased from 2010 to 2011 in the treatments with a higher amount of water appli ed, T1 and T3 (24 and 10 % of yield increase respectively). This was mainly due to an increase in bud fertility (nº of bunches per shoot). Furthermore, sugar content was higher in T3 (27.3 ºBrix), followed by T2 (27 ºBrix). By contrast, T4 (irrigation from veraison) presented the lowest solid soluble concentration and the highest acidity. These results suggest that grapevine has an intrinsic capacity to adapt to its environment. However, this adaptation capacity should be evaluated considering the sensibility of quality parameters during the maturity period (acidity, pH, aroma, color...) and its impact on yield. Here, we demonstrated that a higher amount of water irrigation applied was no linked to a negative effect on quality.

Multiple removal of spent rocket upper stages with an ion beam shepherd

Among the many advantages of the recently proposed ion beam shepherd (IBS) debris removal technique is the capability to deal with multiple targets in a single mission. A preliminary analysis is here conducted in order to estimate the cost in terms of spacecraft mass and total mission time to remove multiple large-size upper stages of the Zenit family. Zenit-2 upper stages are clustered at 71 degrees inclination around 850 km altitude in low Earth orbit. It is found that a removal of two targets per year is feasible with a modest size spacecraft. The most favorable combinations of targets are outlined.

Estudio de los efectos en el viñedo de la modificación del déficit hídrico continuo en los periodos anterior y posterior al envero (cv. Cabernet Sauvignon; Vitis vinifera L.)

En regiones semiáridas, con veranos cálidos, evapotranspiraciones elevadas, humedades relativas bajas, además de precipitaciones intermitentes y escasas (400 mm al año) que reducen la recarga del perfil en invierno, se puede ver afectada la productividad y sostenibilidad de los viñedos. Por eso en estas zonas puede ser necesario utilizar el riego suplementario para mantener la calidad y aumentar la productividad. En este marco de circunstancias es en el que se desarrolla la mayoría de la viticultura española, y en concreto en la zona centro donde se realizó el estudio. Con este trabajo se pretende estudiar la influencia del agua del riego, con distintas dosis y aplicada en diferentes fases de crecimiento y maduración de la baya, en la producción y calidad de la uva. Se estudió la influencia del déficit moderado continuo aplicado antes y después de envero, en el aprovechamiento de los recursos ambientales y en la respuesta del cv. Cabernet Sauvignon. El ensayo se desarrolló en 2010 y 2011 en la finca “La Alcoholera”, perteneciente a bodegas LICINIA S.L., ubicada en la localidad de Chinchón, Comunidad de Madrid, España. Durante 2010 y 2011 se realizaron estudios en cepas del cv. Cabernet Sauvignon (clon 15), injertadas sobre 41B y plantadas en 2005. Con poda corta en Cordón Royat unilateral de 80 cm de altura, y cuya vegetación alcanzó una altura de 97 cm. Las cepas del ensayo fueron conducidas verticalmente en espaldera (VSP), con 10 yemas por metro lineal. Las plantas dentro de la fila fueron separadas 1 m y la distancia de la calle fue de 3 m. La orientación de las filas norte – sur. Se plantearon cuatro tratamientos experimentales con diferentes dosis y momento de aplicación del riego. - T: Testigo. Déficit ligero, con un aporte continuado de agua desde floración (420 mm). - DMc: Déficit moderado continuo. Manejo del riego convencional, empezando en pre-envero (154 mm) - DM1: Déficit moderado a partir de pre-envero. Aporte de riego continuado desde floración reduciéndose la dosis de riego en pre-envero (312 mm). - DM2: Déficit moderado hasta pre-envero. Se empezó a regar a partir de preenvero (230 mm). Se observó que bajo condiciones de estrés hídrico leve, el crecimiento se reduce disminuyendo la migración de fotoasimilados hacia los órganos vegetativos. Generando menor área foliar en las plantas sometidas a déficit hídrico moderado entre floración y cuajado. Disminuyendo su consumo. En maduración la humedad del suelo dependió principalmente del riego aplicado y del consumo de la planta; dicho consumo dependió a la vez del desarrollo foliar del canopy y de la necesidad hídrica de la vid. El aumento del déficit hídrico disminuyó el contenido de agua en el suelo, lo que provocó diferencias en el estado hídrico y en el intercambio gaseoso de las hojas. En condiciones de déficit moderado, la fotosíntesis se encontró altamente correlacionada con el potencial hídrico foliar medido a mediodía solar. Además en condiciones de déficit moderado continuo la disponibilidad hídrica, la demanda atmosférica y el nivel de hidratación de las hojas, interaccionaron de forma compleja en la regulación estomática de las hojas, condicionando el intercambio gaseoso y la eficiencia en el uso del agua. Al aumentar el volumen de agua aplicado el peso de madera de poda por metro de fila fue superior. Las diferencias encontradas en el rendimiento fueron debidas a las diferencias en el peso de baya. El cual estuvo condicionado por la estrategia de riego, ya que, el déficit hídrico moderado antes de envero fue más crítico para el rendimiento que el déficit impuesto durante la madurez. Por otro lado, la biomasa dependió de la actividad fisiológica de la planta, la cual fue altamente dependiente de la disponibilidad hídrica. Déficit hídrico moderado aplicado de cuajado a envero, generó bayas más pequeñas y aumentó la relación hollejo:pulpa. El déficit moderado aplicado después de envero favoreció la acumulación de IPT y antocianos extraíbles, mejorando la calidad de la uva, pero disminuyó la acidez de la baya. El riego aplicado de envero a vendimia desaceleró la concentración de azúcares en bayas que fueron sometidas a déficit antes de pre-envero. ABSTRACT Mediterranean climate is characterized by hot summers, high evapotranspiration rates, and scarce precipitations (400 mm per year) during grapevine cycle. These extremely dry conditions affect vineyard productivity and sustainability. Supplementary irrigation is needed practice in order to maintain yield and quality. Almost all Spanish grape growing regions are characterized by these conditions, especially in the center region, where this trial was performed. The main objective of this work is to study the influence of water irrigation on yield and quality. For this aim, different levels of irrigation (mm of water applied) were applied during different stages of growth and berry maturity of Caberent Sauvignon grapevines. The work was conducted from 2010 to 2011 and located in Licinia (40º 12´ N, 3º 28´ W), Madrid, Spain. The cultivar utilized was Cabernet Sauvignon, clone 15 grafted onto rootstock 41B, planted in 2005. The vineyard was oriented north-south, with spacing on 3 meters between rows and 1 meter between plants. Vines were spurpruned to 10 buds per meter and trained in unilateral cordon with a height of 80 cm. Shoots were positioned vertically (VSP). Considering the amount of water and the moment of the application, four experimental treatments were applied: - T: Control sample. Slight deficit (420 mm) applied from bloom to maturity. - DMc: Continuous moderate deficit. Traditional irrigation: application of 154 mm of water from pre-veraison to maturity. - DM1: Deficit moderate from pre-veraison. Irrigation of 312 mm of water from bloom to pre-veraison. - DM2: Deficit moderate to pre-veraison. Irrigation of 230 mm of water from preveraison to maturity Under moderated water stress conditions it was seen than leaf growth decreases due to the reduction of migration of photo-assimilates to vegetative organs. Vines with moderate water deficit between flowering and ripening develop less leaf area and decrease its water consumption. During maturation of berries, soil moisture depends on irrigation and plant consumption. This consumption further depends on vegetation development and on the vine needs for water. By increasing water deficit, the water content in the soil decreases. This causes differences in leaf water status and in the gases exchange. Under moderate deficit conditions, photosynthesis was found highly correlated with midday leaf water potential. Further, atmospheric demand and the level of leaves hydration interact in complex ways in the stomatal regulation, which affects leaf gas exchange and the efficiency of water use. The amount of water applied is directly proportional to pruning weight. Changes in berry weight cause differences in yield ratios. The differences in berry weights are conditioned by the irrigation strategy, the moderate water deficit before veraison influences more than the deficit applied from veraison. Biomass generated for the plant depends on its physiological activity, which is highly related to the water availability. Moderate water deficit applied from fruit set to ripening generates smaller berries, increasing the pulp/skin ratio. Moderate deficit applied after veraison promotes the accumulation of extractables anthocyans and TPI. Despite this treatment improves color parameters of the grapes, it decreases its total acidity. Irrigation applied from veraison to harvest slows down sugar accumulation in berries compared to those under deficit before veraison conditions.

Effect of cage type on the behaviour pattern of rabbit does at different physiological stages

Interest in commercially farmed rabbit welfare has increased in recent years. As a result, new alternative housing systems have been developed, although they require evaluation in order to demonstrate their potential for improving welfare. The aim of this trial was to study the behavioural traits of rabbit does housed in 2 different types of cage (TC): conventional vs. alternative with an elevated platform, at different physiological stages (PS); lactation and gestation. Behavioural observations were carried out on 12 rabbit commercial does using continuous 24 h video recording. Independently of PS and TC, rabbit does spent most of their time on foot mats (on av. 57.7%). However, due to the use of platforms (on av. 23.0% of time), lactating does spent 36.6% less time on foot mats (P<0.001) and gestating does spent 27.0% less time on wire mesh (P<0.001) in alternative cages than in conventional cages. Alternative cages allowed for standing posture, but this behaviour was only observed in gestating does (on av. 4.6 times a day). Frequency of drinking was higher in conventional than in alternative cages (24.6 vs. 19.1 times a day; P<0.05). Gestating does housed in conventional cages reached the highest duration and frequency of interacting with neighbours (276 s/d and 4.6 times/d; P<0.05). The frequency of interacting with kits was lower in alternative than in conventional cages (2.4 vs. 8.6 times a day; P<0.01). Doe behaviour was influenced by the time of day, with less activity during the midday hours. During dark hours, rabbit does more frequently performed restless behaviour such as hyperactivity or nursing, matching the time at which rabbit does spent more time on the platform. The platform was frequently used by rabbit does, regardless of their physiological stage, and during late lactation phase, when mothers were not receptive to nursing, does housed in alternative cages used the platform as a mean to flee from kits trying to suckle. Use of the platform might lead to hygienic problems due to retained faeces on the platform and faeces and urine falling onto animals located in the lower part of the cage. The absence of stereotypies in rabbit does of this trial, suggested that animal welfare was not compromised by the type of housing (conventional or alternative cages).

Extralimital Senegalese species during Marine Isotope Stages 5.5 and 11 in the Canary Islands (29° N): Sea surface temperature estimates

The presence of Harpa doris Röding, 1798 in marine deposits of the last interglacial period, ~130-120 ka (marine isotope stage or MIS 5.5) in the Canary Islands (Gran Canaria, Lanzarote and Fuerteventura) enabled us to compare this occurrence with its present habitat in the Gulf of Guinea and the Cape Verde Islands, well to the south. This comparison leads to the conclusion that sea surface temperatures (SSTs) in the waters around the Canary Islands during the last interglacial period were at least 3.3 °C higher than today. H. doris is found in association with the large gastropod Persististrombus latus (Gmelin, 1791) as well as the coral Siderastrea radians (Pallas, 1766). The presence of these extralimital southern,warm-water species in the Canary Islands during the last interglacial period also implies a northward expansion of plankton-feeding larvae in seawater with a high chlorophyll-a content. Such conditionswould require a shortening of the southern arm of the cool Canary Current that dominates the waters around the Canary Islands at present. Marine deposits dating to ~400 ka (MIS 11) are also found on the Canary Islands. In these deposits, the presence of Saccostrea cucullata (Born, 1778) allows a comparison with its present habitat in the Gulf of Guinea. In this analysis, we conclude that SSTs in waters around the Canary Islands during this major interglacial period were at least 4.2 °C higher than today. Middle Pleistocene fossils of S. cucullata have also been found in the western Mediterranean Sea and Morocco, as well as the Cape Verde Islands. If these deposits also date to MIS 11, SST warming could have been a regional phenomenon, including much of the eastern Atlantic Ocean and Mediterranean Sea.

Pedro Muguruza Otaño (1893-1952): Aproximación histórica a su obra arquitectónica

El arquitecto Pedro Muguruza (1893-1952) fue protagonista de la cultura arquitectónica española de la primera mitad del siglo XX. El estudio de su obra ha sido una carencia dentro de la historiografía de la materia, por lo que la tesis constituye una primera investigación en conjunto de su trayectoria profesional. Muguruza realizó una obra abundante y diversa, pero además fue catedrático de la Escuela de Arquitectura de Madrid, académico de San Fernando y primer director general de arquitectura; datos que corroboran la necesidad de haber desarrollado una monografía con un enfoque global. La tesis ha ordenado, clasificado y analizado sus trabajos, tanto desde un punto de vista histórico como desde el punto de vista arquitectónico. En la investigación se ha recurrido a fuentes primarias y secundarias; y una de las aportaciones de la tesis es el riguroso soporte documental sobre el que se asienta. El trabajo tiene un desarrollo cronológico, dividido en tres capítulos identificados como las etapas generales de su carrera: 1. Años de formación y trayectorias iniciales (1909- 1923), 2. Desarrollo profesional (1923-1938), 3. Las tareas en la administración estatal y último periodo (1938-1952). Asimismo, se ha llevado a cabo el catálogo de su obra —también ordenado cronológicamente—, herramienta que posibilita recorrer de principio a fin el listado y las referencias de su arquitectura. En este apartado se han reproducido más de 1.200 imágenes de 294 proyectos. La tesis ha revisado y descubierto la obra de un arquitecto de mayor recorrido y versatilidad del conocido hasta ahora; personaje complejo de abordar, asociado al franquismo, —cuando en realidad desarrolló una gran parte de sus proyectos en la década de los años veinte y treinta—, difícil de abarcar en todas sus dimensiones, arquitectónica, artística e institucional. La investigación ha permitido indagar y exponer sus proyectos iniciales hasta los de la etapa de madurez, gracias a lo que se han determinado los géneros y los procesos de su trabajo, las constantes de su trayectoria y las referencias e influencias que recibió, tanto de corrientes nacionales como de extranjeras. También se ha revisado su pensamiento arquitectónico a través de sus escritos. El trabajo ofrece un panorama más completo del que entonces se tenía del polifacético Muguruza; arquitecto que se puede presentar como un prototipo reflejo de nuestro pasado reciente, y que al conocer su obra se conoce una parte significativa y destacada de la historia de la arquitectura española contemporánea. ABSTRACT Architect Pedro Muguruza (1893-1952) was a pivotal figure in the Spanish architectural culture of the first half of the 20th century. However, his work as a whole has been insufficiently approached by architectural historiography. This thesis is indeed the first comprehensive research of his professional career. Muguruza’s work is abundant and diverse. He was also a professor at the School of Architecture in Madrid, a luminary scholar at the Royal Academy of Fine Arts of San Fernando and the first General Director of Architecture in Spain. All these facts compel a profound monographic exploration of his far-reaching working path. Muguruza’s projects have been organized, classified and analyzed in this thesis both from historical and architectural points of view. Primary and secondary sources have been scrutinized throughout this research and one of the assets of this project is the rigorous documentation on which it is firmly grounded. The results of this research have been chronologically organized and structured into three chapters identified with the general stages of his prolific career: 1. Training years and his initial paths (1909-1923). 2. Professional development (1923-1938). 3. His role in the state administration and his last period (1938-1952). A chronological catalogue of all his architectural work has also been carried out as part of this project. This catalogue offers the possibility to track his works and all references to them under a historical perspective. More than 1,200 images of his projects have been included in this catalogue. The thesis has gone through and shown up the work of an architect whose magnitude and versatility is much more than what previously known. Muguruza represents a complicated figure to approach ideologically speaking because of his later relationship to Franco’s regime – when in fact Muguruza developed a big part of his projects in the 20’s and 30’s before the dictatorship –. He is also a difficult figure to research on because of his exhaustive working activity in different dimensions: architectural, artistic and institutional. This research allows any incoming scholars to approach Muguruza’s projects under an accurate perspective. From his initial works to his maturity period, his projects have been analyzed and classified by establishing different stages. Additionally, some constant guidelines within his long career and the influences he received both in Spain and abroad have also been identified and properly considered. His architectural line of thought has been explored through his writings too. This thesis provides a complete overview of a multifaceted Muguruza, an architect who can be introduced as an archetype of our recent cultural heritage. By exploring his work a quintessential part of the Spanish contemporary architecture is definitively revealed and acknowledged.

Cluster microclimate (light and thermal) is a key point of grape maturity in mediterranean semiarid conditions

Se estudian la influencia en el microclima de racimos (temperatura e iluminación) de tres sistemas de conducción en la variedad Syrah en una zona calida.

O DIRETOR ESCOLAR E A IDÉIA DE DEMOCRACIA: UM OLHAR A PARTIR DA FORMAÇÃO

O presente trabalho apresenta uma reflexão e uma discussão em torno dos modelos de democracia, presentes nos gestores e em suas práticas pedagógicas. Essa leitura é feita a partir de processos de formação que incluem toda a trajetória das pessoas envolvidas na busca das formas de apropriação dos ideais de democracia presentes em cada um e em suas etapas de formação para a vida e para a profissão. O suporte teórico pauta-se no ouvir contar , ou seja, nos relatos orais das histórias de vida de cada um dos envolvidos. Infância, dolescência, juventude e maturidade permeiam-se na busca de respostas para os referenciais que cada um dos agentes possui. Dialoguei com as memórias dos entrevistados na busca da descoberta da idéia que cada um dos entrevistados carrega a respeito da gestão democrática. Olhei para as subjetividades e descobri um universo muito mais complexo do que aquele abordado pelas bibliografias a respeito do assunto. Descobri que as pessoas constroem suas concepções ao longo da vida e se relacionam com estas através das situações mais formais, tais como a profissão. O trabalho está estruturado em três capítulos, seguidos de anexos.

O DIRETOR ESCOLAR E A IDÉIA DE DEMOCRACIA: UM OLHAR A PARTIR DA FORMAÇÃO

O presente trabalho apresenta uma reflexão e uma discussão em torno dos modelos de democracia, presentes nos gestores e em suas práticas pedagógicas. Essa leitura é feita a partir de processos de formação que incluem toda a trajetória das pessoas envolvidas na busca das formas de apropriação dos ideais de democracia presentes em cada um e em suas etapas de formação para a vida e para a profissão. O suporte teórico pauta-se no ouvir contar , ou seja, nos relatos orais das histórias de vida de cada um dos envolvidos. Infância, dolescência, juventude e maturidade permeiam-se na busca de respostas para os referenciais que cada um dos agentes possui. Dialoguei com as memórias dos entrevistados na busca da descoberta da idéia que cada um dos entrevistados carrega a respeito da gestão democrática. Olhei para as subjetividades e descobri um universo muito mais complexo do que aquele abordado pelas bibliografias a respeito do assunto. Descobri que as pessoas constroem suas concepções ao longo da vida e se relacionam com estas através das situações mais formais, tais como a profissão. O trabalho está estruturado em três capítulos, seguidos de anexos.

ANÁLISE DAS MUDANÇAS DOS FATORES DETERMINANTES DA ESTRUTURA DE CAPITAL EM FUNÇÃO DO CICLO DE VIDA DAS EMPRESAS BRASILEIRAS

As várias teorias acerca da estrutura de capital despertam interesse motivando diversos estudos sobre o assunto sem, no entanto, ter um consenso. Outro tema aparentemente pouco explorado refere-se ao ciclo de vida das empresas e como ele pode influenciar a estrutura de capital. Este estudo teve como objetivo verificar quais determinantes possuem maior relevância no endividamento das empresas e se estes determinantes alteram-se dependendo do ciclo de vida da empresa apoiada pelas teorias Trade Off, Pecking Order e Teoria da Agência. Para alcançar o objetivo deste trabalho foi utilizado análise em painel de efeito fixo sendo a amostra composta por empresas brasileiras de capital aberto, com dados secundários disponíveis na Economática® no período de 2005 a 2013, utilizando-se os setores da BM&FBOVESPA. Como resultado principal destaca-se o mesmo comportamento entre a amostra geral, alto e baixo crescimento pelo endividamento contábil para o determinante Lucratividade apresentando uma relação negativa, e para os determinantes Oportunidade de Crescimento e Tamanho, estes com uma relação positiva. Para os grupos de alto e baixo crescimento alguns determinantes apresentaram resultados diferentes, como a singularidade que resultou significância nestes dois grupos, sendo positiva no baixo crescimento e negativa no alto crescimento, para o valor colateral dos ativos e benefício fiscal não dívida apresentaram significância apenas no grupo de baixo crescimento. Para o endividamento a valor de mercado foi observado significância para o Benefício fiscal não dívida e Singularidade. Este resultado reforça o argumento de que o ciclo de vida influência a estrutura de capital.

CARACTERÍSTICAS PSICOSSOCIAIS E DE PERSONALIDADE DE ADOLESCENTES INFRATORES EM CUMPRIMENTO DE MEDIDA SOCIOEDUCATIVA

Para atingir os objetivos propostos, ou seja, levantar e descrever indicadores socioculturais de uma amostra de adolescentes em cumprimento de medida socioeducativa, e descrever características psicológicas e de personalidade dos adolescentes infratores, num estudo que pesquisou adolescentes em cumprimento de medida socioeducativa. O trabalho foi realizado em duas as etapas: na primeira, os 47 adolescentes participaram de uma entrevista semidirigida; na segunda, dez desses adolescentes foram selecionados e submetidos a um instrumento projetivo para investigação de aspectos da personalidade: o “desenho da Figura Humana” de Machower, adaptado por Van Kolck (1956; 1984). A discussão teórica dos resultados baseou-se numa abordagem psicanalítica pós-freudiana para a compreensão da adolescência tanto como fase do desenvolvimento humano como dos comportamentos antissociais. Os resultados do estudo corroboraram a teoria advinda da literatura psicológica que aborda padrões comuns no período da adolescência, fase em que ocorre um complexo de fatores individuais da maturidade biológica associados ao meio social/cultural e que, por sua vez, estabelecem relações com as instâncias psicológicas ou psíquicas do sujeito junto com as características específicas de cada indivíduo. Na busca da compreensão desses padrões comuns da amostra dos adolescentes infratores utilizados no presente estudo, foram levantados dados do perfil psicossocial, cultural e demográfico; dos aspectos psicossociais e aspectos psicodinâmicos e de características de personalidade. A título de conclusão, o estudo destacou a problemática do adolescente em conflito com a lei, associada às questões sociais, de saúde mental, além do desenvolvimento psíquico, sinalizando a necessidade de ações psicoprofiláticas voltadas para população infantil, jovem, agrupamentos familiares e para a comunidade que representa seu entorno.

Major histocompatibility complex class I-restricted T cells are required for all but the end stages of diabetes development in nonobese diabetic mice and use a prevalent T cell receptor α chain gene rearrangement

Nonobese diabetic (NOD) mice develop insulin-dependent diabetes mellitus due to autoimmune T lymphocyte-mediated destruction of pancreatic β cells. Although both major histocompatibility complex class I-restricted CD8+ and class II-restricted CD4+ T cell subsets are required, the specific role each subset plays in the pathogenic process is still unclear. Here we show that class I-dependent T cells are required for all but the terminal stages of autoimmune diabetes development. To characterize the diabetogenic CD8+ T cells responsible, we isolated and propagated in vitro CD8+ T cells from the earliest insulitic lesions of NOD mice. They were cytotoxic to NOD islet cells, restricted to H-2Kd, and showed a diverse T cell receptor β chain repertoire. In contrast, their α chain repertoire was more restricted, with a recurrent amino acid sequence motif in the complementarity-determining region 3 loop and a prevalence of Vα17 family members frequently joined to the Jα42 gene segment. These results suggest that a number of the CD8+ T cells participating in the initial phase of autoimmune β cell destruction recognize a common structural component of Kd/peptide complexes on pancreatic β cells, possibly a single peptide.

Posttranscriptional modification of retroviral primers is required for late stages of DNA replication

During reverse transcription of retroviral RNA, synthesis of (−) strand DNA is primed by a cellular tRNA that anneals to an 18-nt primer binding site within the 5′ long terminal repeat. For (+) strand synthesis using a (−) strand DNA template linked to the tRNA primer, only the first 18 nt of tRNA are replicated to regenerate the primer binding site, creating the (+) strand strong stop DNA intermediate and providing a 3′ terminus capable of strand transfer and further elongation. On model HIV templates that approximate the (−) strand linked to natural modified or synthetic unmodified tRNA3Lys, we find that a (+) strand strong stop intermediate of the proper length is generated only on templates containing the natural, modified tRNA3Lys, suggesting that a posttranscriptional modification provides the termination signal. In the presence of a recipient template, synthesis after strand transfer occurs only from intermediates generated from templates containing modified tRNA3Lys. Reverse transcriptase from Moloney murine leukemia virus and avian myoblastosis virus shows the same requirement for a modified tRNA3Lys template. Because all retroviral tRNA primers contain the same 1-methyl-A58 modification, our results suggest that 1-methyl-A58 is generally required for termination of replication 18 nt into the tRNA sequence, generating the (+) strand intermediate, strand transfer, and subsequent synthesis of the entire (+) strand. The possibility that the host methyl transferase responsible for methylating A58 may provide a target for HIV chemotherapy is discussed.