Texas A&M University

About: Texas A&M University is a education organization based out in College Station, Texas, United States. It is known for research contribution in the topics: Population & Gene. The organization has 72169 authors who have published 164372 publications receiving 5764236 citations.

Arsenite and arsenate adsorption on ferrihydrite : Surface charge reduction and net OH- release stoichiometry

Abstract: Arsenite [As(III)] and arsenate [As(V)] are highly toxic inorganic arsenic species that represent a potential threat to the environment and human health. Iron oxides including poorly crystalline oxides, e.g., ferrihydrite, play a significant role in controlling dissolved As concentration and limit the mobility and bioavailability of As(III) and As(V). Adsorption occurs by ligand exchange of the As species for OH2 and OH- in the coordination spheres of surface structural Fe atoms. The objective of this study was to evaluate H+/OH- release stoichiometry and changes in surface charge properties of the adsorbent during the adsorption of arsenite and arsenate on ferrihydrite in the pH range of 4−10. This information, which is not directly accessible through spectroscopic studies, provides important clues to bonding mechanism. While arsenate adsorption resulted in the net release of OH- at pH 4.6 and 9.2, arsenite adsorption resulted in net OH- release at pH 9.2 and net H+ release at pH 4.6. The amount of H+ or...

An invariant dimensional liability model of gender differences in mental disorder prevalence: evidence from a national sample.

Abstract: Epidemiological studies of categorical mental disorders consistently report that gender differences exist in many disorder prevalence rates and that disorders are often comorbid Can a dimensional multivariate liability model be developed to clarify how gender impacts diverse, comorbid mental disorders? We pursued this possibility in the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC; N 43,093) Gender differences in prevalence were systematic such that women showed higher rates of mood and anxiety disorders, and men showed higher rates of antisocial personality and substance use disorders We next investigated patterns of disorder comorbidity and found that a dimensional internalizing-externalizing liability model fit the data well, where internalizing is characterized by mood and anxiety disorders, and externalizing is characterized by antisocial personality and substance use disorders This model was gender invariant, indicating that observed gender differences in prevalence rates originate from women and men’s different average standings on latent internalizing and externalizing liability dimensions As hypothesized, women showed a higher mean level of internalizing, while men showed a higher mean level of externalizing We discuss implications of these findings for understanding gender differences in psychopathology and for classification and intervention