University of Alabama

About: University of Alabama is a education organization based out in Tuscaloosa, Alabama, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 27323 authors who have published 48609 publications receiving 1565337 citations. The organization is also known as: Alabama & Bama.

Evidence for two active branches for electron transfer in photosystem I

Abstract: All photosynthetic reaction centers share a common structural theme. Two related, integral membrane polypeptides sequester electron transfer cofactors into two quasi-symmetrical branches, each of which incorporates a quinone. In type II reaction centers [photosystem (PS) II and proteobacterial reaction centers], electron transfer proceeds down only one of the branches, and the mobile quinone on the other branch is used as a terminal acceptor. PS I uses iron-sulfur clusters as terminal acceptors, and the quinone serves only as an intermediary in electron transfer. Much effort has been devoted to understanding the unidirectionality of electron transport in type II reaction centers, and it was widely thought that PS I would share this feature. We have tested this idea by examining in vivo kinetics of electron transfer from the quinone in mutant PS I reaction centers. This transfer is associated with two kinetic components, and we show that mutation of a residue near the quinone in one branch specifically affects the faster component, while the corresponding mutation in the other branch specifically affects the slower component. We conclude that both electron transfer branches in PS I are active.

Four-year longitudinal study of conduct disorder in boys: patterns and predictors of persistence.

Abstract: A prospective study of conduct disorder (CD) was conducted using 4 annual structured diagnostic interviews of 171 clinic-referred boys, their parents, and their teachers. Only about half of the 65 boys who met criteria for CD in Year 1 met criteria again during the next year, but 88% met criteria for CD again at least once during the next 3 years. For most boys with CD, the number of symptoms fluctuated above and below the diagnostic threshold from year to year but remained relatively high. Lower socioeconomic status, parental antisocial personality disorder (APD), and attention-deficit hyperactivity disorder were significant correlates of CD in Year 1, but the interaction of parental APD and the boy's verbal intelligence predicted the persistence of CD symptoms over time (i.e., only boys without a parent with APD and with above-average verbal intelligence clearly improved). Conduct disorder (CD) is a pattern of maladaptive behavior of children that is characterized by a variety of antisocial behaviors, including physical aggression, deception, and violation of the property rights of others (Lahey, Loeber, Frick, Quay, & Grimm, 1992). It is generally considered to be a serious childhood disorder that is the primary precursor to chronic antisocial behavior during adulthood (Kazdin, 1987a; Robins, Tipp, & Pryzbeck, 1991). Because it is difficult to reduce the frequency of antisocial behavior in children with CD through psychosocial treatment (Kazdin, 1987b), CD is conceptualized as a disorder that is usually chronic (Kazdin, 1987a). Evidence from longitudinal studies is consistent with the view that antisocial behavior in childhood is persistent over time; however, these same data raise a question about the degree of persistence of the disorder. For example, studies of official court records have shown that 50%-70% of youths who are arrested for delinquent acts during childhood or adolescence are arrested in adulthood (Loeber, 1982, 1990, 1991;McCord, 1979;

Multiple Roles of Carbonic Anhydrase in Cellular Transport and Metabolism

Abstract: Carbonic anhydrase (CA) is a central enzyme to both transport and metabolic processes at the cellular level. In metabolically active tissue such as muscle, CA in the cytoplasm and on the sarcolemma appears to be important in facilitating CO2 transport out of the cell. Membrane-associated CA, with an extracellular orientation, also appears to be important in acidifying the outer boundary layer through the catalyzed hydration of excreted CO2. This facilitates cellular ammonia transport by providing H+ ions for the protonation of NH3, thus maintaining the trans-membrane NH3 gradient. Mitochondrial CA is known to supply HCO3- for the initial reactions of gluconeogenesis and ureagenesis in mammalian tissues, but systematic comparative studies of CA as a metabolic enzyme are lacking. CA probably evolved as an enzyme of trans-membrane facilitated CO2 transport and took on a secondary metabolic role later in metazoan evolution.

Causes of Peace: Democracy, Interdependence, and International Organizations, 1885–1992

Abstract: Previous studies provide strong evidence for the Kantian theory of peace, but a satisfactory evaluation requires establishing the causal influence of the variables. Here we focus on the reciprocal relations between economic interdependence and interstate conflict, 1885–1992. Using distributed-lags analyses, we find that economically important trade does have a substantively important effect in reducing dyadic militarized disputes, even with extensive controls for the influence of past conflict. The benefit of interdependence is particularly great in the case of conflict involving military fatalities. Militarized disputes also cause a reduction in trade, as liberal theory predicts. Democracy and joint membership in intergovernmental organizations, too, have important pacific benefits; but we find only limited support for the role of costly signals in establishing the liberal peace. We find no evidence that democratization increases the incidence of interstate disputes; and contrary to realists' expectations, allies are not less conflict prone than states that are not allied. Democracies and states that share membership in many international organizations have higher levels of trade, but allies do not when these influences are held constant.