The Mosca (Chibcha)

Author Institution: Sociology and Anthropology, The Ohio State University, Columbus 1

The Human Brain as a Preadaptive Factor in the Development of Culture

Author Institution: Department of Sociology and Anthropology, The Ohio State Universit

Estratègies d'afrontament i símptomes depressius en el postpart

Malgrat que la maternitat s'associa a benestar emocional, el període perinatal és una etapa de gran vulnerabilitat a patir algun problema psíquic. Al voltant d'un 10% de les mares tindran una depressió postpart, que afecta tant la mare com el futur desenvolupament de l'infant. Una recerca en què ha participat una investigadora de la UAB ha estudiat de forma conjunta el paper de les estratègies d'afrontament, algunes característiques de la personalitat, l'estrès i el suport social percebut de les mare en l'aparició de simptomatologia depressiva tant a les 8 com a les 32 setmanes de donar a llum.A pesar de que la maternidad se asocia a bienestar emocional, el período perinatal es una etapa de gran vulnerabilidad a sufrir algún problema psíquico. Alrededor de un 10% de las madres tendrán una depresión postparto, que afecta tanto a la madre como al futuro desarrollo del niño. Una investigación en la que ha participado una investigadora de la UAB ha estudiado de forma conjunta el papel de las estrategias de afrontamiento, algunas características de la personalidad, el estrés y el apoyo social percibido de las madre en la aparición de sintomatología depresiva tanto a las 8 como a las 32 semanas de dar a luz

Transitional periods of the atmospheric boundary layer

The atmospheric boundary layer is the part of the troposphere influenced by the presence of the surface, and where most weather phenomena occur. During the day, with fair weather conditions, a convective boundary layer exists. In contrast, during the night, a stable boundary layer appears. It is important to note that the evolution from a convective boundary layer to a stable boundary layer and vice versa happens through two transitional processes. Due to its complexity and the rapid variability, there is a lack of studies about the morning or afternoon/evening transitions. This thesis wants to solve some of the uncertainties related with the morning and afternoon/evening transition of the atmospheric boundary layer. It is based on observations from the project Boundary-Layer Late Afternoon and Sunset Turbulence (BLLAST) and numerical simulation experiments developed with mixed-layer and large-eddy simulation models. In this thesis, we develop an analysis focused on the role played by the residual layer during the morning transition and by the large-scale subsidence on the evolution of the boundary layer. DALES numerical experiments that include the residual layer are capable of modeling the observed sudden increase of the boundary-layer depth during the morning transition and the subsequent evolution of the boundary layer. These simulations show a large increase in the entrainment buoyancy flux when the residual layer is incorporated into the mixed layer. We also examine how the inclusion of the residual layer above a shallow convective boundary layer modifies the turbulent kinetic energy budget. Large-scale subsidence mainly acts when the boundary layer is fully developed and, for the studied day, it is necessary to consider this in order to reproduce the afternoon observations. Finally, we also investigate how CO2 stored the previous night in the residual layer plays a fundamental role in the evolution of the CO2 mixing ratio during the following day. Moreover, we hypothesize that during the evening transition a delay exists between the instant when the buoyancy flux goes to zero and the time when the local gradient of the virtual potential temperature changes sign contradict the assumption in which are base the gradient-based turbulence models. The results from this work confirm and quantify a flux-gradient delay. Specifically, the observed values of the delay are between approximately 30 and 80 min. The existence of the delay and its duration can be explained by considering the convective time and the competition of forces associated with the classical Rayleigh-Bénard problem. This combined theory predicts that the last eddy formed should produce a delay when the sensible heat flux changes sign during the evening transition. It appears that this last eddy is decelerated through the action of turbulent momentum and thermal diffusivity, and that the delay is related to the convective turnover time. Observations indicate that, as horizontal shear becomes more important, the delay time apparently increases to values greater than the convective turnover time. Finally, we study the existence and characteristics of Lifted Temperature Minimum (LTM) during the evening transition. The study shows that LTM can be detected in calm conditions already during day¿night transition, several hours earlier than the usual time of occurrence reported by previous works. These conditions are fulfilled when weak synoptic forcing exists and the local flow shifts from valley to mountain breeze in a relatively complex orography. Under these special conditions, turbulence becomes a crucial parameter to determine the ideal conditions for observing LTM. Additionally, the correlation of longwave radiation measured at 0.8 m and estimated at the ground varies when the LTM is observed. Therefore, LTM is also related to a change in the atmospheric radiative characteristics under calm conditions.La capa límit atmosfèrica és la part de la troposfera influenciada per la presència de la superfície terrestre, i on es produeixen la majoria dels fenòmens meteorològics. Durant el dia, en condicions de bon temps, es forma una capa límit convectiva. En canvi, durant la nit, apareix una capa límit estable. L'evolució d'una capa límit convectiva a una capa límit estable i viceversa passa a través de dos processos de transició. A causa de la seva complexitat i la ràpida variació, hi ha una manca d'estudis sobre les transicions del dia a la nit o viceversa. Aquesta tesi vol resoldre algunes de les incerteses relacionades amb les transicions de la capa límit atmosfèrica. La tesi es basa en les observacions obtingudes durant la campanya Boundary-Layer Late Afternoon and Sunset Turbulence i simulacions numèriques desenvolupades amb dos models: un model de capa de mescla i un model de tipus large-eddy simulation. Primerament, es desenvolupa una anàlisi centrada en el paper de la capa residual durant la transició entre la nit i el dia i en el paper de la subsidència en l'evolució de la capa límit. Les simulacions que inclouen la capa residual són capaces de modelar l’augment sobtat de l’alçada de la capa límit durant aquesta transició i també la posterior evolució de la capa límit. Aquestes simulacions mostren un gran augment del flux que entra des de la atmosfera lliure quan la capa residual s'incorpora a la capa convectiva. També s’analitza els efectes de considerar la capa residual en el balanç d'energia cinètica turbulenta. La subsidència actua principalment quan la capa límit està totalment desenvolupada i , pel dia seleccionat, cal tenir-la en compte per tal de reproduir les observacions durant la tarda. Finalment, també investiguem com el diòxid de carboni (CO2) emmagatzemat a la capa residual juga un paper fonamental en l'evolució del CO2 durant el dia. En segon lloc, s'analitza el fet de que durant la transició del dia a la nit hi ha una demora entre el moment en què el flux de flotació esdevé zero i el moment en què el gradient de la temperatura potencial virtual canvia de signa. Aquest fet contradiu el supòsit en què estan basats els models de simulació. Els resultats d'aquest treball confirmen i quantifiquen aquest demora. Específicament, els valors observats de la demora són aproximadament d'entre 30 i 80 min. L'existència de la demora i la seva durada es pot explicar a través del temps convectiu i de les forces associades amb el problema de Rayleigh-Bénard. La teoria proposada considera que l'últim remolí format abans de cessament del flux de superfície produeix el retard en el canvi de signe del gradient del flux de calor. Alhora aquest últim remoli es pot frenar a través de l'acció de la viscositat i la difusivitat tèrmica, i el retard està relacionat amb el temps que dura el recorregut del remolí. Les observacions indiquen que, com més important és el cisallament de vent horitzontal, el temps de retard aparentment augmenta a valors més grans que el temps convectiu. Finalment , s'estudia l'existència i característiques d'un Mínim Elevat de Temperatura (LTM) durant la transició entre el dia i la nit. L'estudi mostra que el LTM es pot detectar en condicions de calma durant aquesta transició hores abans de l'hora d’observació descrita en els treballs anteriors. Aquestes condicions de calma es compleixen quan les forces sinòptiques són febles i el vent local canvia de direcció en una orografia relativament complexa (durant el dia prové de la vall i durant la nit de la muntanya). En aquestes condicions especials, la turbulència es converteix en un paràmetre fonamental per determinar les condicions ideals per a l'observació de LTM. A més, la correlació de la radiació d'ona llarga mesurada a 0,8 m i estimada a terra varia quan s'observa el LTM. Per tant, el LTM també està relacionada amb un canvi de les característiques radiatives de l’atmosfera en condicions de calma.Postprint (published version

In Vitro Mutagenesis for Structure/Function Studies of the Bacteriophage T4 Rega Protein and the Murine AHR Protein

The bacteriophage T4 regA protein translationally represses over 30 T4 early genes, including the regA gene, by binding to the translation initiation region of the T4 mRNAs (Karam et al., 1981). Although the recognition sequence has been at least partially characterized in a number regA sensitive mRNAs, there is no consensus sequence or structural feature that is recognized by regA in all transcripts (Winter et al., 1987; Webster et al., 1989; Unnithan et al., 1990). Recent studies have identified an RNA binding site on regA protein, but there remains a large gap in our understanding of how regA protein functions to temporally repress multiple mRNAs (Gordon et aI., 1999). A genetic screen was developed to further identify regA protein:RNA interaction sites. This approach uses a two-plasmid system in which lacZ expression is placed under the translational control of T4 regA via the gene 44 recognition element (gene 44 RE) (AAUGAGGAAAUU) on plasmid pLacZ-44RE. For regA expression the regA gene was cloned into a pACYC derivative thereby placing expression of regA under the control of a strong IPTG inducible promoter. The two plasmids were then transformed into the E. coli strain WM1/F\u27. This approach allowed the rapid selection of regA mutants with altered RNA binding affinity using a blue/white selection process. After selection, the regA mutants were further characterized by sequencing of the mutant genes, as well as by gel mobility shift assays with the mutant proteins and an RNA oligo of the gene 44 RE. Beta-galactosidase assays were also performed to quantify repression levels obtained by IPTO induction of regA in cells transformed with the mutant regAs. In subsequent experiments, the gene 44 RE was mutated at two of the twelve bases in order to vary regA affinity for the binding site and thereby vary regA repression of the lacZ mRNA translation. In another experiment the Shine-Dalgamo sequence upstream of the lacZ gene was weakened to reduce b-galactosidase expression. Blue/white assays were performed to determine if these base mutations produced variations in color due to variable expression of beta-galactosidase. After comparing lacZ expression from plasmids with the various gene 44 RE mutants, the regA gene was randomly mutagenized and the blue/white screen was used to look for gain of function mutants. Potential mutants were expected to be altered in their RNA binding specificity. The mutant colonies were sequenced to identify specific mutations, in an effort to identify residues that are important in the recognition and binding of RNA targets. The effects of individual mutations were further assayed by the use of gel mobility shift and β-galactosidase assays. In other experiments color screening assays were performed to compare cells expressing T4 regA with cells expressing the regA homologue found in bacteriophage RB69. Previous studies had indicated that RB69 regA had a greater affinity for RNA than did T4 regA, in vitro. The in vivo color assays were performed to determine if the higher affinity in vitro translated into greater repression of lacZ in vivo. Results from these screens indicate that the hierarchy of repression of lacZ expression is from plasmids with different gene 44 REs is different for T4 regA and RB69 regA proteins. The work described in Chapter II of this thesis is concerned with the aryl hydrocarbon receptor protein (AHR). Recent studies have shown that the AHR protein is rapidly degraded both in vivo and in vitro after exposure to agonist (Pollenz, R.S., 1996; Giannone et al., 1998; Giannone et al., 1995; Pollenz et al., 1998; Roman et al., 1998; Sommer et al., 1998). Additionally, it has been shown that the AHR contains putative Nuclear Export Signal (NES) and Nuclear Localization Signal (NLS) sequences (Davarinos and Pollenz, 1999; Ikuta et al., 1999; Pollenz and Barbour, 2000). The purpose of the studies detailed in this thesis was to generate plasmids which express AHR mutant proteins that contain mutant NES or NLS sequences but are unimpaired in all other aspects of AHR functionality. These studies have shown that it is possible to generate AHR proteins with mutations in the NES that dimerizes with ARNT, binds DNA and supports ligand-mediated gene induction. These studies have also shown that AHR proteins with mutant NLS sequences are also capable of dimerizing with ARNT and binding to DNA. Additionally, these studies have indicated that the NLS mutants were degraded more slowly after agonist exposure than wild type AHR suggesting another level of regulation of the AHR pathway