University of Memphis

About: University of Memphis is a education organization based out in Memphis, Tennessee, United States. It is known for research contribution in the topics: Population & Poison control. The organization has 7710 authors who have published 20082 publications receiving 611618 citations. The organization is also known as: U of M.

The lida architecture: adding new modes of learning to an intelligent, autonomous, software agent

Abstract: This is a report on the LIDA architecture, a work in progress that is based on IDA, an intelligent, autonomous, "conscious" software agent that does personnel work for the US Navy. IDA uses locally developed cutting edge artificial intelligence technology designed to model human cognition. IDA's task is to find jobs for sailors whose current assignments are about to end. She selects jobs to offer a sailor, taking into account the Navy's policies, the job’s needs, the sailor's preferences, and her own deliberation about feasible dates. Then she negotiates with the sailor, in English via iterative emails, about job selection. We use the word "conscious" in the sense of Baars' Global Workspace Theory (Baars, 1988, 1997), upon which our architecture is based.

The sharp threshold for bootstrap percolation in all dimensions

Abstract: In r-neighbour bootstrap percolation on a graph G, a (typically random) set A of initially 'infected' vertices spreads by infecting (at each time step) vertices with at least r already-infected neighbours. This process may be viewed as a monotone version of the Glauber dynamics of the Ising model, and has been extensively studied on the d-dimensional grid $[n]^d$. The elements of the set A are usually chosen independently, with some density p, and the main question is to determine $p_c([n]^d,r)$, the density at which percolation (infection of the entire vertex set) becomes likely. In this paper we prove, for every pair $d ge r ge 2$, that there is a constant L(d,r) such that $p_c([n]^d,r) = [(L(d,r) + o(1)) / log_(r-1) (n)]^{d-r+1}$ as $n o infty$, where $log_r$ denotes an r-times iterated logarithm. We thus prove the existence of a sharp threshold for percolation in any (fixed) number of dimensions. Moreover, we determine L(d,r) for every pair (d,r).

Insomnia and complicated grief symptoms in bereaved college students.

Abstract: In this study, we extended previous research by concentrating on sleep- and grief-related symptoms in a cohort of bereaved college students, in view of the potential for each of these problems to exacerbate the other. A sample of 815 college students completed the Inventory of Complicated Grief (H. G. Prigerson & S. C. Jacobs, 2001), along with an assessment of diagnostic criteria for insomnia and associated sleep behaviors. As predicted, the rate of insomnia was significantly higher (22%) in the bereaved sample than in a nonbereaved comparison group (17%), a difference that was particularly pronounced in terms of middle insomnia. Also as hypothesized, bereaved insomniacs reported higher complicated grief scores than bereaved noninsomniacs, and several specific sleep variables (including sleep-onset insomnia related to nighttime rumination about the loss and sleep-maintenance insomnia associated with dreaming of the deceased) were significantly related to complicated grief symptomatology.

Maternal BMI at the start of pregnancy and offspring epigenome-wide DNA methylation: findings from the pregnancy and childhood epigenetics (PACE) consortium

Abstract: Pre-pregnancy maternal obesity is associated with adverse offspring outcomes at birth and later in life. Individual studies have shown that epigenetic modifications such as DNA methylation could contribute. Within the Pregnancy and Childhood Epigenetics (PACE) Consortium, we meta-analysed the association between pre-pregnancy maternal BMI and methylation at over 450,000 sites in newborn blood DNA, across 19 cohorts (9,340 mother-newborn pairs). We attempted to infer causality by comparing the effects of maternal versus paternal BMI and incorporating genetic variation. In four additional cohorts (1,817 mother-child pairs), we meta-analysed the association between maternal BMI at the start of pregnancy and blood methylation in adolescents. In newborns, maternal BMI was associated with small (<0.2% per BMI unit (1 kg/m2), P < 1.06 × 10-7) methylation variation at 9,044 sites throughout the genome. Adjustment for estimated cell proportions greatly attenuated the number of significant CpGs to 104, including 86 sites common to the unadjusted model. At 72/86 sites, the direction of the association was the same in newborns and adolescents, suggesting persistence of signals. However, we found evidence for acausal intrauterine effect of maternal BMI on newborn methylation at just 8/86 sites. In conclusion, this well-powered analysis identified robust associations between maternal adiposity and variations in newborn blood DNA methylation, but these small effects may be better explained by genetic or lifestyle factors than a causal intrauterine mechanism. This highlights the need for large-scale collaborative approaches and the application of causal inference techniques in epigenetic epidemiology.

Patterns of waterpipe use and dependence: implications for intervention development.

Abstract: Despite the dramatic increase of tobacco smoking via waterpipe in Arab societies, and the apparent potential of waterpipe use to produce tobacco-related disease, little is known about the pharmacological effects of this method of tobacco smoking, particularly its ability to support dependence. This review focuses on recent waterpipe research and current theories of dependence in an attempt to identify patterns of waterpipe use and features likely to reveal dependence. Recent work indicates that, relative to cigarette smoking, this form of tobacco use is characterized by more intermittent use, later age of onset, greater spread among women and lower interest in quitting or appreciation of addictive properties. Waterpipe use is associated with classic features of tobacco/nicotine dependence, as well as features unique to this tobacco use method. However, even shared features of dependence, such as craving and addiction-induced socio-cognitive behavioral changes, can be displayed differently in waterpipe users, indicating the need for waterpipe-specific research approaches. Preliminary evidence suggests that an important step toward dependence involves a transition from social to individual patterns of waterpipe use. Surveillance and research into factors affecting use and cessation of this tobacco use method should pave the way for the development of effective prevention and intervention strategies to curb the burgeoning waterpipe use epidemic.