University of California, Irvine

About: University of California, Irvine is a education organization based out in Irvine, California, United States. It is known for research contribution in the topics: Population & Galaxy. The organization has 47031 authors who have published 113602 publications receiving 5521832 citations. The organization is also known as: UC Irvine & UCI.

Enhanced Human Memory Consolidation With Post-Learning Stress: Interaction With the Degree of Arousal at Encoding

Abstract: Abundant evidence indicates that endogenous stress hormones such as epinephrine and corticosterone modulate memory consolidation in animals. We recently provided the first demonstration that an endogenous stress hormone (epinephrine) can enhance human memory consolidation. However, these findings also suggested that post-learning stress hormone activation does not uniformly enhance memory for all recently acquired information; rather, that it interacts with the degree of arousal at initial encoding of material in modulating memory for the material. Here we tested this hypothesis by administering cold pressor stress (CPS) or a control procedure to subjects after they viewed slides of varying emotional content, and assessing memory for the slides 1 wk later. CPS, which significantly elevated salivary cortisol levels, enhanced memory for emotionally arousing slides compared with the controls, but did not affect memory for relatively neutral slides. These findings further support the view that post-learning stress hormone-related activity interacts with arousal at initial encoding to modulate memory consolidation.

Ages, Life Stages, and Generational Cohorts: Decomposing the Immigrant First and Second Generations in the United States

Abstract: This article focuses on problems with the definition and empirical identification of immigrant “first” and “second” generations in the United States. These loosely conceived aggregates are decomposed into a typology of distinct generational cohorts defined by age and life stage at migration for the foreign born and by parental nativity for the U.S. born. Differences in educational and occupational attainment and in language and other aspects of acculturation are then examined to consider whether the practice of “lumping” these generational cohorts together, or “splitting” them into distinctive units of analysis, is empirically supported by available evidence. The paper concludes with some thoughts on data needs and methodological considerations in the study of immigrant generations. “All the world's a stage, and all the men and women merely players: They have their exits and their entrances; and one man in his time plays many parts, his acts being seven ages …” — William Shakespeare, “As You Like It,”Act II, Scene 7.

Out of Sight, Out of Mind: The Effects of Expenses on Mutual Fund Flows

Abstract: We argue that the purchase decisions of mutual fund investors are influenced by salient, attention-grabbing information. Investors are more sensitive to salient in-your-face fees, like front-end loads and commissions, than operating expenses; they are likely to buy funds that attract their attention through exceptional performance, marketing, or advertising. Our empirical analysis of mutual fund flows over the last 30 years yields strong support for our contention. We find consistently negative relations between fund flows and front-end load fees. We also document a negative relation between fund flows and commissions charged by brokerage firms. In contrast, we find no relation (or a perverse positive relation) between operating expenses and fund flows. Additional analyses indicate that mutual fund marketing and advertising, the costs of which are often embedded in a fund's operating expenses, account for this surprising result.

Altered Distribution of Nicotinamide-Adenine Dinucleotide Phosphate—Diaphorase Cells in Frontal Lobe of Schizophrenics Implies Disturbances of Cortical Development

Abstract: Epidemiological and anatomical studies support the theory that disturbances of brain development may play a contributory role in the etiology of schizophrenia. Anatomical findings suggest that the normal pattern of neuronal migration during development of the cerebral cortex may be affected in the brains of schizophrenics, with the implication that cortical connectivity and associative function will be disrupted. In the present investigation in matched schizophrenic and control brains, we examined a particular population of neurons found in the prefrontal cortex and underlying white matter and characterized by histochemical staining for the enzyme nicotinamide-adenine dinucleotide phosphate-diaphorase. In normal brains, these neurons are found in highest numbers in the white matter immediately deep to layer VI of the cortex where they remain from the subplate, an early formed, but transitory structure that plays a key role in cortical development and connection formation. The dorsolateral prefrontal area of schizophrenics showed a significant decline in nicotinamide-adenine dinucleotide phosphate-diaphorase neurons in the superficial white matter and in the overlying cortex but a significant increase in these neurons in white matter deeper than 3 mm from the cortex. These findings are consistent with a disturbance of the subplate during development in which the normal pattern of programmed cell death is compromised and accompanied by a defect in the normal orderly migration of neurons toward the cortical plate. These are likely to have serious consequences for the establishment of a normal pattern of cortical connections leading to a potential breakdown of frontal lobe function in schizophrenics.

Sarcopenia: etiology, clinical consequences, intervention, and assessment

Abstract: The aging process is associated with loss of muscle mass and strength and decline in physical functioning. The term sarcopenia is primarily defined as low level of muscle mass resulting from age-related muscle loss, but its definition is often broadened to include the underlying cellular processes involved in skeletal muscle loss as well as their clinical manifestations. The underlying cellular changes involve weakening of factors promoting muscle anabolism and increased expression of inflammatory factors and other agents which contribute to skeletal muscle catabolism. At the cellular level, these molecular processes are manifested in a loss of muscle fiber cross-sectional area, loss of innervation, and adaptive changes in the proportions of slow and fast motor units in muscle tissue. Ultimately, these alterations translate to bulk changes in muscle mass, strength, and function which lead to reduced physical performance, disability, increased risk of fall-related injury, and, often, frailty. In this review, we summarize current understanding of the mechanisms underlying sarcopenia and age-related changes in muscle tissue morphology and function. We also discuss the resulting long-term outcomes in terms of loss of function, which causes increased risk of musculoskeletal injuries and other morbidities, leading to frailty and loss of independence.