Morphogenesis of the Arabidopsis Shoot Apical Meristem

Phyllotaxis patterns in plants, or the arrangement of leaves and flowers radially around the shoot, have fascinated both biologists and mathematicians for centuries. The current model of this process involves the lateral transport of the hormone auxin through the first layer of cells in the shoot apical meristem via the auxin efflux carrier protein PIN1. Locations around the meristem with high auxin concentration are sites of organ formation and differentiation. Many of the molecular players in this process are well known and characterized. Computer models composed of all these components are able to produce many of the observed phyllotaxis patterns. To understand which parts of this model have a large effect on the phenotype I automated parameter testing and tried many different parameter combinations. Results of this showed that cell size and meristem size should have the largest effect on phyllotaxis. This lead to three questions: (1) How is cell geometry regulated? (2) Does cell size affect auxin distribution? (3) Does meristem size affect phyllotaxis? To answer the first question I tracked cell divisions in live meristems and quantified the geometry of the cells and the division planes using advanced image processing techniques. The results show that cell shape is maintained by minimizing the length of the new wall and by minimizing the difference in area of the daughter cells. To answer the second question I observed auxin patterning in the meristem, shoot, leaves, and roots of Arabidopsis mutants with larger and smaller cell sizes. In the meristem and shoot, cell size plays an important role in determining the distribution of auxin. Observations of auxin in the root and leaves are less definitive. To answer the third question I measured meristem sizes and phyllotaxis patterns in mutants with altered meristem sizes. These results show that there is no correlation between meristem size and average divergence angle. But in an extreme case, making the meristem very small does lead to a switch on observed phyllotaxis in accordance with the model.

South Road

SOUTH ROAD, a novel told in third-person limited, follows Adrienne Harris as she navigates the trials of her coming-of-age summer and then must deal with the aftermath. 1997: seventeen-year-old Adrienne Harris wants nothing more than to flee her eccentric grandmother’s rule and leave Harbor Point and never look back. When she meets her new neighbors, Adrienne knows her life will never be the same. Adrienne quickly falls in love with the charismatic Quinn Merritt. They decide to keep their relationship a secret since both families disapprove. This secret starts a chain reaction that seemingly leads to the suicide of the troubled and poetic Lucas Merritt. The summer culminates with Adrienne running away, pregnant and heartbroken. 2011: thirty-one-year-old Adrienne is an out of work line cook and single mother. The story opens as Adrienne reluctantly returns home to Harbor Point to care for her ailing grandmother. Once home, Adrienne has to confront the things that haunt her—the summer she met and lost both Merritt brothers, and also her dysfunctional relationship with her grandmother—in order to heal and repair her own life and her relationship with her daughter. In the end, Adrienne discovers many truths that alter her perception of her past in Harbor Point. Adrienne is finally able to move forward and start to build a life for her and her daughter. Harbor Point, the last place in the world Adrienne Harris wanted to be, turns out to be the only place she wants to call home.

Prenatal Diagnosis of Infantile Neuroaxonal Dystrophy

Infantile Neuroaxonal Dystrophy (INAD1, MIM # 256600), is a rare autossomal recessive neurodegenerative disorder. The clinical picture is characterized by psychomotor regression and hypotonia, which progresses to spastic tetraplegia, visual impairment and dementia. Onset is within the first 2 years of life and death usually happens before the age of 10. In 2006, Morgan et al described that mutations in PLA2G6 gene localized in chromosome 22 (22q13), caused INAD1. Evidence showed that a large proportion of patients with infantile neuroaxonal dystrophy have a mutation in the PLA2G6 gene. A 36-years-old pregnant woman presented for obstetric follow up. It was the second pregnancy of this healthy, nonconsanguineous couple. Their 7 year-old daughter was affected with Infantile Neuroaxonal Dystrophy. Molecular testing was done in the child and, as a causal mutation was detected, it was possible to offer a specific prenatal diagnosis. The molecular study of PLA2G6 gene by amniocentesis showed the presence of a mutation in heterozygoty and the karyotype was normal for a female foetus. To our knowledge, this is the first molecular prenatal diagnosis of INAD1 in Portugal.

Miguel Sawa y la Revista "Don Quijote" (1892-1903)

In late 19th century and early 20th coexisted in time in Spain a lot of writers, many of them well known today, but many others who haven’t been rescued yet. This stage has been called the Silver Age of Spanish literature. Among the best known and most representative of Madrid’s bohemian characters were the Sawa brothers: Manuel, Alejandro, Miguel and Enrique. All of them had related to the literature or journalism, in greater or lesser extent, and were very significant figures in their time. Alejandro, who reached a high literary level, has recently been subject of various studies and biographies which have located him in his place as a outstanding writer, rescuing him from forgetting where he remained sunk until a few decades ago. But it has not happened the same with the rest of the brothers, especially with Miguel, who was also a writer. The object of the first part of this thesis is to recover the figure of the Miguel Sawa, rebuilding his biography and both journalistic and literary career. Miguel Sawa, belonging to the so-called generation of literarian bohemia, born in Seville in 1866. After moving with his family to Málaga, where he spent his childhood, settled definitively in Madrid in 1880. In Madrid lived the atmosphere of the newspapers offices and the literarian gatherings of the “cafes”. He was a friend of Valle Inclán, the Machado brothers, the Baroja brothers, and belonged to the “Gente Nueva” and to the Germinal generation. In 1901 he married María Palacio, with whom he had a son, Emilio, who died before completing one year of life, and a daughter, Carmen, who had five years when Sawa died. After spending a season in La Coruña, as director of the newspaper La Voz de Galicia, returned to Madrid at the beginning of 1910, ready to continue his literary career, but died suddenly on 1 October of that same year because of a fulminant pneumonia...

Violência conjugal percebida por um menor em contexto familiar e suas consequências psicossociais

A violência como fenómeno social e familiar, não é um problema atual, desde sempre esteve presente, sendo que a sua exposição apresenta diferentes intensidades em diferentes momentos da sua evolução. Como fenómeno mundial, percorreu todas as culturas, etnias, tipos de economia e regimes políticos (Sagim, 2003). O objectivo da presente investigação é a violência conjugal percebida por um menor em contexto familiar e suas consequências psicossociais: estudo de caso. Método: A metodologia escolhida é qualitativa e é designada por naturalista. O método utilizado foi o estudo de caso e a recolha de dados foi a entrevista (semi-estruturada) e fez-se a descodificação desta através da análise de conteúdo, que foi organizada em várias categorias . Instrumentos: Questionário sócio demográficos (filha); Guião de Entrevista para adultos(mãe), semi-estruturada; Entrevista Clínica Semi–Estruturada (SCICA);A Escala de Sinalização do Ambiente Natural Infantil (S.A.N.I.); O teste projectivo Pata Negra de Corman (filha). Participantes: R de 12 anos de idade, sexo feminino, caucasiana, possui o 9º ano de escolaridade Resultados: Verificou-se que R tem uma boa capacidade de coping e resolução de problemas, indo do encontro referido por alguns autores nos meus estudos, sendo que noutros não se enquadra no perfil defendido pela literatura. Referindo segundo o DSM-5, R apresenta alguma sintomatologia clínica como a ansiedade de separação, revelando insegurança e medo da perda dos afetos por parte dos progenitores. Conclusão: : Concluiu-se ainda que alguns estudos referem que nem todas as crianças expostas à violência intrafamiliar responderão negativamente, uma vez que a presença de fatores de proteção tèm um papel fundamental. Entre estes, o ambiente escolar, o relacionamento com a vizinhança e o suporte advindo de demais membros familiares, entre outros (Sani, 2008).

Scaling laws and thermodynamic analysis for vascular branching of microvessels

When blood flows through small vessels, the two-phase nature of blood as a suspension of red cells (erythrocytes) in plasma cannot be neglected, and with decreasing vessel size, a homogeneous continuum model become less adequate in describing blood flow. Following the Haynes’ marginal zone theory, and viewing the flow as the result of concentric laminae of fluid moving axially, the present work provides models for fluid flow in dichotomous branching composed by larger and smaller vessels, respectively. Expressions for the branching sizes of parent and daughter vessels, that provides easier flow access, are obtained by means of a constrained optimization approach using the Lagrange multipliers. This study shows that when blood behaves as a Newtonian fluid, Hess – Murray law that states that the daughters-to-parent diameter ratio must equal to 2^(-1/3) is valid. However, when the nature of blood as a suspension becomes important, the expression for optimum branching diameters of vessels is dependent on the separation phase lengths. It is also shown that the same effect occurs for the relative lengths of daughters and parent vessels. For smaller vessels (e. g., arterioles and capillaries), it is found that the daughters-to-parent diameter ratio may varies from 0,741 to 0,849, and the daughters-to-parent length ratio varies from 0,260 to 2,42. For larger vessels (e. g., arteries), the daughters-to-parent diameter ratio and the daughters-to-parent length ratio range from 0,458 to 0,819, and from 0,100 to 6,27, respectively. In this paper, it is also demonstrated that the entropy generated when blood behaves as a single phase fluid (i. e., continuum viscous fluid) is greater than the entropy generated when the nature of blood as a suspension becomes important. Another important finding is that the manifestation of the particulate nature of blood in small vessels reduces entropy generation due to fluid friction, thereby maintaining the flow through dichotomous branching vessels at a relatively lower cost.