Anatomy of Malicious Singularities

As well known, the b-boundaries of the closed Friedman world model and of Schwarzschild solution consist of a single point. We study this phenomenon in a broader context of differential and structured spaces. We show that it is an equivalence relation $\rho$, defined on the Cauchy completed total space $\bar{E}$ of the frame bundle over a given space-time, that is responsible for this pathology. A singularity is called malicious if the equivalence class $[p_0]$ related to the singularity remains in close contact with all other equivalence classes, i.e., if $p_0 \in \mathrm{cl}[p]$ for every $p \in E$. We formulate conditions for which such a situation occurs. The differential structure of any space-time with malicious singularities consists only of constant functions which means that, from the topological point of view, everything collapses to a single point. It was noncommutative geometry that was especially devised to deal with such situations. A noncommutative algebra on $\bar{E}$, which turns out to be a von Neumann algebra of random operators, allows us to study probabilistic properties (in a generalized sense) of malicious singularities. Our main result is that, in the noncommutative regime, even the strongest singularities are probabilistically irrelevant.Comment: 16 pages in LaTe

Towards understanding the impacts of congestion pricing on urban trucking

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2005.Includes bibliographical references (p. 107-111).Understanding policy impacts on freight is essential for planners who have overlooked this transport group in the past and must evaluate new congestion alleviation policies with respect to regional economic and social goals. Since urban areas are limited in infrastructure expansion and travel demand continues to rise, congestion pricing is a potentially compelling policy alternative. This thesis focuses on measuring the impacts of congestion pricing policies on urban freight. We differentiate from prior studies which measure the impacts of urban freight and present tools to measure the impacts on urban freight according to three stakeholder groups: shippers, carriers, and the public sector. We recognize that the impacts of urban freight may be the motivators for policy change or project implementation and the continued study of these impacts is critical to the public sector who aims to minimize externalities of increasing truck traffic (and is also an urban freight stakeholder); however, we suggest that the impacts that these projects or polices have on freight is particularly important given the economic value associated with goods movement. For each of these stakeholder groups, we evaluate their goals, enumerate the possible responses to the scheme, and provide tools to quantify the impacts. First, we summarize the experiences of urban freight in other congestion pricing schemes and review several implementation decisions from the perspective of freight stakeholders. Second, we characterize possible freight responses to transportation improvement policies. Third, we expand previous freight impact analyses by quantifying the first-order impacts of the scheme for each stakeholder group.(cont.) Finally, we propose additional research extensions related to analyzing the higher-order impacts of freight and using the methods here as a means to introduce public- and private-sector collaboration.by Janine M. Waliszewski.S.M

DIFERENCIAS EN CONCENTRACIÓN DE PLAGUICIDAS ORGANOCLORADOS PERSISTENTES EN SUELO, PAJA Y GRANOS DE TRIGO

Crops incorporate pesticide residues through the roots and adsorb particles and vapors on their surface. The concentrations of organochlorine pesticides were determined in soil and wheat plants in order to observe their distribution from soil through growing plants. The determinations were done by gas chromatography. The minor concentrations corresponded to HCB (hexachlorobenzene), they were 0.7 μg/kg in soil, 0.9 μg/kg in grains, and 1.3 μg/kg in straw. The isomer á-HCH (hexachlorcyclohexane) presented 0.7 μg/kg in soil, 4.6 μg/kg in grains and 5.8μg/kg in straw. The Lindane concentrations were 3.9 μg/kg in soil, 5.8 μg/kg in grains, and 30.9μg/kg in straw. For the DDT’s, the minor concentrations corresponded to pp’DDE, and they were 1.0 μg/kg in soil, 7.4 μg/kg in grains, and 10.8 μg/kg in straw. The op’DDT presented levels of 30.0 μg/kg in soil, 21.5 μg/kg in grains, and 25.6 μg/kg in straw. The insecticide pp’DDT concentrations were 65.6 μg/kg in soil, 63.6 μg/kg in grains, and 46.9 μg/kg in straw. In conclusion, the accumulated pesticides in agricultural soils were mobilized permitting their penetration and adsorption through the growing plants, producing an unexpected source of contamination for consumers.Los cultivos agrícolas incorporan residuos de plaguicidas del suelo por las raíces y adsorben vapores y partículas en su superficie. Para este trabajo se analizaron los niveles de plaguicidas organoclorados en suelo y plantas de trigo para observar su distribución desde el suelo hacia las plantas, utilizándose la técnica de cromatografía de gases. La menor concentración correspondió al HCB (hexaclorobenceno) y fue de 0.7 μg/kg en suelo, 0.9 μg/kg en granos y 1.3 μg/kg en paja. El isómero á-HCH (hexaclorociclohexano) presentó 0.7 μg/kg en suelo, 4.6 μg/kg en granos y 5.8 μg/kg en paja. El Lindano mostró 3.9 μg/kg en suelo, 5.8 μg/kg en granos y 30.9 μg/kg en paja. De los DDT, el nivel más bajo correspondió al pp’DDE con 1.0 μg/kg en suelo, 7.4 μg/kg en granos y 10.8 μg/kg en paja. El op’DDT mostró el nivel de 30.0 μg/kg en suelo, 21.5 μg/kg en granos y 25.6 μg/kg en paja. El insecticida pp’DDT reveló 65.6 μg/kg en suelo, 63.6 μg/kg en granos y 46.9 μg/kg en paja. En conclusión, al movilizarse los plaguicidas acumulados en los suelos agrícolas penetran a las plantas de trigo y son una fuente de contaminación adicional para los consumidores

NIVELES DE DDT EN TEJ IDO ADIPOSO MATERNO, SUERO SANGUÍNEO Y LECHE DE MADRES RESIDENTES EN VERACRUZ, MÉXICO. ESTUDIO 1997-1999

The levels of DDT and metabolites were determined in maternal adipose tissue, maternal blood serum and mature milk of 112 volunteers in order to observe the gradient of concentrations. The results obtained indicated the highest concentration of metabolite pp’DDE in adipose tissue at 3.76 mg/kg, followed by 3.49 mg/kg in blood serum and 3.23 mg/kg in mature milk. The same tendency was revealed for the insecticide pp’DDT with 0.97 mg/kg in adipose tissue, 0.82 mg/kg in blood serum and 0.51 mg/kg in mature milk. The higher concentrations of total DDT in mature milk correspond to the suburban population at 4.84 mg/kg compared to 2.49 mg/kg for the Veracruz population. Moreover, the elevation of their levels according to age was observed ranging from 2.97 mg/kg in mothers under 20 years of age, up to 4.60 mg/kg in mothers over 40. There was also a decreased tendency with parity from 4.10 mg/kg in primiparous to 3.41 mg/kg in triparous. The DDT accumulated in maternal adipose tissue forms an equilibrium with blood serum and then is excreted with the endogenous fat of maternal milk.Se determinaron los niveles del DDT y sus metabolitos en tejido adiposo materno, suero materno y leche materna madura de 112 voluntarias para observar el posible gradiente de concentración. Los resultados indicaron mayor concentración del metabolito pp’DDE en tejido adiposo con 3.76 mg/kg, seguido por 3.49 mg/kg en suero sanguíneo y 3.23 mg/kg en leche materna madura. La misma tendencia reveló el insecticida pp’DDT con 0.97 mg/kg en tejido adiposo, 0.82 mg/kg en suero sanguíneo y 0.51 mg/kg en leche madura. La mayor concentración del DDT total en leche madura se determinó en la población suburbana de 4.84 mg/kg en comparación con 2.49 mg/kg en la de Veracruz, así como un ascenso con la edad de 2.97 mg/kg en madres menores de 20 años a 4.60 mg/kg en madres mayores de 40 años y un descenso con la paridad con 4.10 mg/kg en primíparas y 3.41 mg/kg en tríparas. El DDT acumulado en el tejido adiposo materno forma un equilibrio con el suero sanguíneo y se excreta con las grasas endógenas que participan en la formación de la leche.

NIVELES DE PLAGUICIDAS ORGANOCLORADOS EN CARNE Y GRASA DE BOVINO PROCEDENTES DE VERACRUZ, MÉXICO

The levels of organochlorine pesticides in 218 samples of fat and 165 samples of organs and meat Collected from bovines slaughtered in the municipal slaughterhouse of Veracruz were determined during 1994. Analysis were carried out by gas chromatography with electron capture detector. From the analyzedresidues, pp'DDT presented the highest mean levels in organs and meat, reaching the maximum meanlevel of 2.713 mg/kg in lung samples, that was statistically difierent (p<0.05) composed with mean levels of other organs. The mean levels of HCB in fat samples from abdominal cavities and the mean levels oftotal DDT in fat samples from abdominal cavities were statistically different (p<<O.O5). Apparently, the overall coiitamination with organochlorine pesticides was found to be higher than in other countries. Nevertheless, these concentrations were bellow the United States tolerarice limits, except for the β-HCH.Durante 1994 se colectaron un total de 218 muestras de tejido adiposo de diversas regiones anatómicas y 165 muestras de distintas vísceras y músculos de bovinos sacrificados en el rastro municipal de la ciudad de Veracruz que se analizaron por cromatografía de gases con detector de captura de electrones para determinar la presencia y distribución de la contaminación por plaguicidas organoclorados. El pp'DDT presentó los niveles promedio más altos encontrados en vísceras y músculos, como es el caso en vísceras de pulmón de 2.713 mg/kg, estadísticamente diferente (p<0.05) a los valores medios detectados en otras vísceras. Se hallaron diferencias estadísticamente significativas (p<0.05) en los niveles medios del HCB de las grasas de la cavidad abdominal, así como entre los niveles del DDT total de la grasa abdominal. Los niveles de los plaguicidas organoclorados manifestados en las muestras revelaron la existencia de una contaminación mayor a la reportada en otros países. Sin embargo, estos valores se encontraron por debajo de las tolerancias establecidas en los Estados Unidos de América con excepción del β-HCH

MODULADORES HORMONALES AMBIENTALES Y SALUD HUMANA

Los contaminantes ambientas presentes en el entorno humano debido a su resistencia a la degradación, bioacumulación y ubicuidad pueden producir efectos tóxicos inesperados afectando a la salud humana. A este grupo de compuestos, pertenecen los organoclorados que incluyen los insecticidas organoclorados. Ellos pueden interferir en el balance hormonal, actuando como disruptores o moduladores que cambian la homeostasis hormonal. Su actividad considera una posible interacción con el receptor estrogénico, acción antiandrogénica o  el cambio en el metabolismo del estradiol que aumenta la producción de metabolitos con mayor fuerza al receptor estrogénico. Esto produce una acelerada proliferación celular y la probabilidad de desarrollar neoplasias.  Abstract The environmental pollutants presented in the human environment, due to the persistence, bioaccumulation and ubiquity can cause toxic effects affecting human health. To the group of compounds belong organochlorine that include the organochlorine pesticides. These compounds can interfere with hormone balance, acting as disrupter’s o modulators that changed hormonal homeostasis. Their activity considers the possible interaction with estrogen receptor, action as antiandrogenic or by change in estradiol metabolism that increase metabolite production with higher reactivity to estrogen receptor. The effect results in accelerated cell proliferation and probability to neoplasm development. Palabras clave: compuestos organoclorados, moduladores hormonales

TENDENCIA DE 1988 A 1998 DE LOS NIVELES DE PLAGUICIDAS ORGANOCLORADOS PERSISTENTES EN TEJIDO ADIPOSO HUMANO EN VERACRUZ, MÉXICO

In México more than 270 active ingredients of pesticides used in agriculture, sanitation and industry are permitted. Among the organochlorine pesticides the most important, due to their properties of biomagnification in the food chain, are DDT and Lindane. From 1988 to 1998 a total of 326 samples of human adipose tissue were analysed. A significant contamination with DDT and its metabolite (DDE) was observed during the study period, reaching the maximum mean values of 6.67 mg/kg and 18.91 mg/kg on fat basis, respectively. This contamination may be caused by the aspiration of DDT vapors used in sanitary actions against malary and by the consumption of contaminated food of animal origin.En la República Mexicana están permitidos más de 270 ingredientes activos de plaguicidas para usos agrícola, sanitario e industrial. Entre los insecticidas organoclorados, los de mayor importancia por sus propiedades de biomagnifícación en la cadena trófica, son el DDT y el Lindano. En el período de 1988 a 1998 se analizaron 326 muestras de tejido adiposo humano. Se observó durante el transcurso del estudio contaminación elevada por DDT y su metabolito DDE, que alcanzó valores máximos de 6.67 mg/kg y 18.91 mg/kg en base lipídica, respectivamente. Esta contaminación puede deberse a la aspiración de los vapores del DDT rociado en el entorno durante el combate sanitario del paludismo y al consumo de alimentos contaminados de origen animal

Self-Aligned Bilayers for Flexible Free-Standing Organic Field-Effect Transistors

[Image: see text] Free-standing and flexible field-effect transistors based on 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-pentacene)/polystyrene bilayers are obtained by well-controlled phase separation of both components. The phase separation is induced by solvent vapor annealing of initially amorphous blend films, leading to crystallization of TIPS-pentacene as the top layer. The crystallinity and blend morphology strongly depend on the molecular weight of polystyrene, and under optimized conditions, distinct phase separation with a well-defined and trap-free interface between both fractions is achieved. Due to the distinct bilayer morphology, the resulting flexible field-effect transistors reveal similar charge carrier mobilities as rigid devices and additionally pronounced environmental and bias stress stabilities. The performance of the flexible transistors remains stable up to a strain of 1.8%, while above this deformation, a close relation between current and strain is observed that is required for applications in strain sensors