Estudo da adsorção/dessorção do ácido 2,4 diclorofenoxiacético (2,4d) em solo na ausência e presença de matéria orgânica

The herbicides are being used in huge quantities for various porpouses. Once the herbicide finds its way into the environment, a major part of it comes in contact with soil. Humic substances are major organic constituents of soil. These substances may interact with herbicides in different modes and adsorption is probably the most important one. Adsorption will control the quantity of herbicide in the soil solution, and determines its persistence, leaching, mobility and bioavailability. In this work we studied the interaction between the herbicide 2,4D and soil in the presence and absence of organic matter. The methodology utilized for the determination of 2,4D was gas chromatography with eletron capture detector. The behavior of 2,4D was evaluated through Freundlich isotherms. It was verified that the herbicide 2,4D has a large adsorption in the humic acid .

4D-aikataulutuksen mahdollisuudet voimalaitosprojekteissa

4D-aikataulutus yhdistää aikataulun ja 3D-mallin animaatioelokuvaksi, jossa projektin rakentuminen esitetään ajan funktiona. Tässä työssä on perehdytty 4D-aikataulutukseen voimalaitosprojektien kannalta. Lisäksi työssä on perehdytty projektijohtamiseen, ja sitä kautta aikataulun merkitykseen projekteille. Työn lopuksi on esitetty 4D-aikataulutuksen käyttöönottoa ja siinä huomioon otettavia seikkoja. 4D-aikataulutuksen avulla projektin asennussuunnittelua voidaan toteutusvaiheessa tehostaa, sillä 4D-aikataulutuksen avulla asennusten törmäysten tarkastelua voidaan tehdä hyvissä ajoin suunnitteluvaiheessa. Lisäksi vaihtoehtoisten asennusmallien tekeminen on mahdollista, ja niitä voidaan keskenäään vertailla. Projektit voivat 4D-aikataulutuksen avulla analysoida myös aikatauluviiveitä, sekä esittää vaihtoehtoisia toteutustapoja projektille. 4D-aikataulutus mahdollistaa myös projektivaiheiden jälkeisen käytön. Projektin jälkeen projektin suunnitteltua ja toteutunutta aikataulua voidaan analysoida keskenään ja siten saada toisiin projekteihin vertailukelpoista tietoa. Lisäksi seisokkitöiden suunnittelussa on 4D-aikataulun avulla mahdollista suunnitella töiden järjestäminen tehokkaasti sekä ottaa myös turvallisuusnäkökohdat huomioon.

Les polymorphismes des gènes encodant les protéines apoptotiques Bim et Bax : leur rôle dans la réponse thérapeutique chez les enfants ayant la leucémie lymphoblastique aiguë

INTRODUCTION Des réponses thérapeutiques variables aux glucocorticoïdes (GCs) sont observées parmi les patients atteints de la leucémie lymphoblastique aiguë (LLA). Les protéines Bax et Bim ont déjà montré un rôle important dans l’apoptose des cellules leucémiques. L’expression de Bax était plus basse chez les patients leucémiques résistants au médicament, de même une sensibilité diminuée aux GCs a été associée avec une expression réduite de Bim. La différence dans l’expression pourrait être due à des polymorphismes présents dans ces gènes et donc être associés avec la résistance aux GCs. MÉTHODE Dix-huit polymorphismes en régions régulatrices, 2 polymorphismes exoniques et 7 polymorphismes en région 3’UTR de ces gènes ont été analysés chez les témoins (n=50) et ont permis de déterminer un nombre minimal de polymorphismes suffisants pour définir les haplotypes (tagSNPs). Ces 8 polymorphismes ont ensuite été génotypés chez 286 enfants atteints de la LLA et ont été testés pour l’issue de la maladie par l’analyse de survie. RÉSULTATS Une survie sans évènement et une survie sans rechute diminuées ont été observées pour l’haplotype 3 (p=0,03 et p=0,02). Une survie globale diminuée a été associée avec l’homozygotie pour l’allèle exonique T298C>T (p=0,03), de même que pour les haplotypes 1 et 4 (p=0,04 et p=0,02) du gène Bim. CONCLUSION Les polymorphismes ont été associés avec une survie diminuée chez des enfants atteints de LLA. Il reste à tester d’autres polymorphismes présents dans ces deux gènes ainsi qu’à définir leurs fonctions afin de comprendre leurs rôles dans la réponse aux GCs.

Modélisation MHD tridimensionnelle de tubes de flux coronaux utilisant l'assimilation des donnés 4D-VAR

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

2D, 3D and 4D active compound delivery in tissue engineering and regenerative medicine

Recent advances in tissue engineering and regenerative medicine have shown that controlling cells microenvironment during growth is a key element to the development of successful therapeutic system. To achieve such control, researchers have first proposed the use of polymeric scaffolds that were able to support cellular growth and, to a certain extent, favor cell organization and tissue structure. With nowadays availability of a large pool of stem cell lines, such approach has appeared to be rather limited since it does not offer the fine control of the cell micro-environment in space and time (4D). Therefore, researchers are currently focusing their efforts on developing strategies that include active compound delivery systems in order to add a fourth dimension to the design of 3D scaffolds. This review will focus on recent concepts and applications of 2D and 3D techniques that have been used to control the load and release of active compounds used to promote cell differentiation and proliferation in or out of a scaffold. We will first present recent advances in the design of 2D polymeric scaffolds and the different techniques that have been used to deposit molecular cues and cells in a controlled fashion. We will continue presenting the recent advances made in the design of 3D scaffolds based on hydrogels as well as polymeric fibers and we will finish by presenting some of the research avenues that are still to be explored.

Replicated nil associations of digit ratio (2D:4D) and absolute finger lengths with implicit and explicit measures of aggression. 'Replicaci??n de asociaciones nulas del ratio del segundo y cuarto dedo (2D:4D) y la longitud absoluta de los dedos con medidas de agresi??n impl??citas y expl??citas'

Resumen tomado de la publicaci??n

Análisis de la evolución en las prácticas de Mejoramiento Integral de Barrios (BIM) en la Gestión Urbana de Bogotá entre 1995-2011

La ciudad informal en las periferias urbanas ha sido una de las mayores preocupaciones de las grandes ciudades latinoamericanas. Distintos enfoques a este problema han derivado en distintas formas de abordarlo a partir de la política pública. En el caso de Bogotá, los Programas de Mejoramiento Integral han permitido visibilizar, intervenir e integrar grandes porciones de suelo objeto de procesos de urbanizaciones incompletas, dando solución a miles de familias que han tenido que asentarse de forma emergente y bajo condiciones urbanas muy precarias. De hecho, Bogotá se ha convertido en una referencia nacional e internacional sobre la forma en que se ha implementado este tipo de programa. Sin embargo, al hacer un repaso sobre las enseñanzas que ha dejado esta experiencia, se encuentra información pública limitada y se evidencia una pérdida de la memoria institucional sobre su operación y resultados.

Thermal expansion of deuterated hopeite, Zn-3(PO4)(2)center dot 4D(2)O

The lattice parameters extracted from Lebail analysis of neutron powder diffraction data collected between 2 and 300 K have been used to calculate the temperature evolution of the thermal expansion tensor for hopeite, Zn-3(PO4)(2)center dot 2H(2)O, Pnma,Z=4with a= 10.6065(4) angstrom, b = 18.2977(4) angstrom, c= 5.0257(2) A at 275 K. The a lattice parameter shows a negative thermal expansion, the b lattice parameter appears to saturate at 275 K while the c lattice parameter has a more typical positive thermal expansion. At 275 K, the magnitudes of the thermal expansion coefficients are alpha(a) = -1. 1(4) x 10(-5) K-1, alpha(b) = 2.4(9) x 10(-6) K-1 and alpha(c) = 3.6(2) x 10(-1) K-1. Under the conditions of these experiments, hopeite begins to dehydrate to the dihydrate between 300 and 325 K, and between 480 and 500 K the monohydrate is formed. The thermal expansion of the dihydrate has been calculated between 335 and 480 and at 480 K the magnitudes of the thermal expansion coefficients are alpha(a) = 1(2) x 10(-5) K-1, alpha(b) = 4(l) x 10(-6) K-1, alpha(c) = 4(2) x 10(-5) K-1, alpha(beta) = 1 (1) x 10(-1) K-1, and alpha(v) = 2(2) x 10(-1) K-1. The thermal expansion of hopeite is described in terms of its crystal structure and possible dehydration mechanisms for the alpha and beta modifications of hopeite are discussed.

A singular vector perspective of 4D-Var: Filtering and interpolation

Four-dimensional variational data assimilation (4D-Var) combines the information from a time sequence of observations with the model dynamics and a background state to produce an analysis. In this paper, a new mathematical insight into the behaviour of 4D-Var is gained from an extension of concepts that are used to assess the qualitative information content of observations in satellite retrievals. It is shown that the 4D-Var analysis increments can be written as a linear combination of the singular vectors of a matrix which is a function of both the observational and the forecast model systems. This formulation is used to consider the filtering and interpolating aspects of 4D-Var using idealized case-studies based on a simple model of baroclinic instability. The results of the 4D-Var case-studies exhibit the reconstruction of the state in unobserved regions as a consequence of the interpolation of observations through time. The results also exhibit the filtering of components with small spatial scales that correspond to noise, and the filtering of structures in unobserved regions. The singular vector perspective gives a very clear view of this filtering and interpolating by the 4D-Var algorithm and shows that the appropriate specification of the a priori statistics is vital to extract the largest possible amount of useful information from the observations. Copyright © 2005 Royal Meteorological Society

Can 4D-Var use dynamical information from targeted observations of a baroclinic structure?

Targeted observations are generally taken in regions of high baroclinicity, but often show little impact. One plausible explanation is that important dynamical information, such as upshear tilt, is not extracted from the targeted observations by the data assimilation scheme and used to correct initial condition error. This is investigated by generating pseudo targeted observations which contain a singular vector (SV) structure that is not present in the background field or routine observations, i.e. assuming that the background has an initial condition error with tilted growing structure. Experiments were performed for a single case-study with varying numbers of pseudo targeted observations. These were assimilated by the Met Office four-dimensional variational (4D-Var) data assimilation scheme, which uses a 6 h window for observations and background-error covariances calculated using the National Meteorological Centre (NMC) method. The forecasts were run using the operational Met Office Unified Model on a 24 km grid. The results presented clearly demonstrate that a 6 h window 4D-Var system is capable of extracting baroclinic information from a limited set of observations and using it to correct initial condition error. To capture the SV structure well (projection of 0.72 in total energy), 50 sondes over an area of 1×106 km2 were required. When the SV was represented by only eight sondes along an example targeting flight track covering a smaller area, the projection onto the SV structure was lower; the resulting forecast perturbations showed an SV structure with increased tilt and reduced initial energy. The total energy contained in the perturbations decreased as the SV structure was less well described by the set of observations (i.e. as fewer pseudo observations were assimilated). The assimilated perturbation had lower energy than the SV unless the pseudo observations were assimilated with the dropsonde observation errors halved from operational values. Copyright © 2010 Royal Meteorological Society