A role for the developing lexicon in phonetic category acquisition

Infants segment words from fluent speech during the same period when they are learning phonetic categories, yet accounts of phonetic category acquisition typically ignore information about the words in which sounds appear. We use a Bayesian model to illustrate how feedback from segmented words might constrain phonetic category learning by providing information about which sounds occur together in words. Simulations demonstrate that word-level information can successfully disambiguate overlapping English vowel categories. Learning patterns in the model are shown to parallel human behavior from artificial language learning tasks. These findings point to a central role for the developing lexicon in phonetic category acquisition and provide a framework for incorporating top-down constraints into models of category learning

Time, action and psychosis: using subjective time to investigate the effects of ketamine on sense of agency

Sense of agency refers to the experience of initiating and controlling actions in order to influence events in the outside world. A disturbed sense of agency is found in certain psychiatric and neurological disorders, most notably schizophrenia. Sense of agency is associated with a subjective compression of time: actions and their outcomes are perceived as bound together in time. This is known as ‘intentional binding’ and, in healthy adults, depends partly on advance prediction of action outcomes. Notably, this predictive contribution is disrupted in patients with schizophrenia. In the present study we aimed to characterise the psychotomimetic effect of ketamine, a drug model for psychosis, on the predictive contribution to intentional binding. It was shown that ketamine produced a disruption that closely resembled previous data from patients in the early, prodromal, stage of schizophrenic illness. These results are discussed in terms of established models of delusion formation in schizophrenia. The link between time and agency, more generally, is also considered

Assessment of alternative strategies for sludge disposal into deep ocean basins off Southern California

The general framework of engineering alternatives for regional ocean sludge disposal is well described in a report by Raksit, and will not be repeated here. The various ocean disposal alternatives are less costly than all land-disposal and incineration/pyrolysis systems studied. Even though ocean sludge disposal is currently contrary to both state and federal regulations, it is hoped that this study will advance our scientific and engineering knowledge of the behavior and effects of sludge discharge in deep water, in case the regulatory policy is reexamined in the future. With this report we hope we have demonstrated the potential and difficulties of some new modeling techniques for predicting the effects of sludge discharge in the ocean. In the future. we believe it will be possible to formulate policy of ocean sludge discharges with much better case-by-case predictions of impacts for comparison with other alternatives (such as land disposal). not only for the Los Angeles/Orange County areas, but for all coastal urban areas

Research report: 1983-1985

The Environmental Quality Laboratory at Caltech is a center for research on large scale systems problems of natural resources and environmental quality. The principal areas of investigation at EQL are: 1. Air quality management. 2. Water resources and water quality management. 3. Control of hazardous substances in the environment. 4. Energy policy, including regulation, conservation and energy-environment trade-offs. 5. Resources policy (other than energy); residuals management. EQL research includes technical assessments, computer modeling, studies of environmental control options, policy analyses, and research on important components of the large scale systems. Field work is also undertaken at EQL, some in collaboration with other organizations, to provide critical data needed for evaluation of systems concepts and models. EQL's objectives are as follows: 1. To do systematic studies of environmental and resources problems. The results of these studies, including the clarification of policy alternatives. are communicated to decision-makers in government and industry, to the research community, and to the public. As an organization. EQL refrains from advocating particular policies, but seeks to point out the implications of the various policy alternatives. 2. To contribute to the education and training of people in these areas through involvement of pre-doctoral students, post-doctoral fellows, and visiting faculty members in EQL activities. This educational effort is just as important as the results of the studies themselves, and should make lasting contributions to the nation's ability to solve its environmental and resources problems. The work at EQL goes beyond the usual academic research in that it tries to organize and develop the knowledge necessary to clarify society's alternatives by integrating relevant disciplines. EQL works on solving problems of specific localities when there is a strong element of public interest or educational value, or the concepts and results are applicable to other places. The research of EQL is done under the supervision of faculty members in Environmental Engineering Science, Chemical Engineering, and Social Science. This research report covers the period from October 1983 through September 1985

The Social Psychology Of Perception Experiments: Hills, Backpacks, Glucose, And The Problem Of Generalizability

Experiments take place in a physical environment but also a social environment. Generalizability from experimental manipulations to more typical contexts may be limited by violations of ecological validity with respect to either the physical or the social environment. A replication and extension of a recent study (a blood glucose manipulation) was conducted to investigate the effects of experimental demand (a social artifact) on participant behaviors judging the geographical slant of a large-scale outdoor hill. Three different assessments of experimental demand indicate that even when the physical environment is naturalistic, and the goal of the main experimental manipulation was primarily concealed, artificial aspects of the social environment (such as an explicit requirement to wear a heavy backpack while estimating the slant of a hill) may still be primarily responsible for altered judgments of hill orientation. (PsycINFO Database Record (c) 2013 APA, all rights reserved)(journal abstract

Effects of maternal separation on brain stress systems: Modulation by voluntary exercise in male rats

Early life stress (ELS) has been shown to predispose animals to anxiety- and depression-like behaviour in adulthood. Recent evidence suggests that repeated stress in adulthood dysregulates the hypothalamic orexin/hypocretin system. The current study examined the effects of maternal separation (MS), a well validated rodent model of ELS, on the expression of anxiety-like behaviour following the re-exposure to stress in adulthood. The pattern of Fos-expression in hypothalamic orexin neurons and stress sensitive brain regions was also characterised. Finally, this study examined whether the effects of this double-hit of stress could be reversed using a voluntary exercise intervention during early adulthood. Male rat pups (n=25) were removed from dams for 3hrs on postnatal days (PND) 2-14 (MS). Controls (C; n=25) remained undisturbed during this period except for weekly weighing. On PND 75, animals were randomly allocated to either a ‘stress’ (30min restraint stress) or ‘no stress’ condition (S or NS). A subset of MS animals (n=6) was allowed access to exercise wheels for 1hr/day from PND 40-70. Following this, all animals were behaviourally tested in the open field apparatus for 10mins. Two hours after initiation of restraint, animals were perfused and brains were processed for Fos-protein immunohistochemistry and co-labelled for orexin or tyrosine-hydroxylase (TH). Counts of Fos-positive neurons were made in the hypothalamus, paraventricular nucleus (PVN), paraventricular thalamus (PVT) and ventral tegmental area (VTA). MS-NS rats exhibited behaviour that was indistinguishable from C-NS rats. However, male MS-S rats exhibited decreased exploratory behaviour in the open field task compared to C-S rats. This was associated with a decrease in the percentage of Fos-positive orexin cells in the hypothalamus and reduced Fos-protein in the PVN, PVT and TH-positive VTA cells compared to C-S rats. Interestingly, the exercise intervention reversed the behavioural effects of MS following stress and normalized orexin cell and VTA-TH cell Fos-expression. In conclusion, MS resulted in altered open field behaviour and hypoactivation of the orexin system in response to adult stress. The current study indicates that changes in orexin system function may involve altered activity in stress-sensitive brain regions such as the VTA, PVN and PVT. Importantly, the behavioural and neural changes observed were reversed by voluntary exercise in early adulthood. These findings highlight the importance of non-pharmacological interventions in the treatment of stress-related disorders

Insulinlike Growth Factor 1- and 2-Augmented Collagen Gel Repair of Facial Osseous Defects

BACKGROUND: Defects of the facial bone structure are common problems for the facial plastic surgeon. Native type 1 collagen gels (T1CGs) have been shown to mediate repair of facial critical-size defects in rat models. OBJECTIVE: To evaluate the efficacy of T1CG augmented with insulinlike growth factor (IGF) 1, IGF-2, and a combination of IGF-1 and IGF-2 on the repair of facial critical-size defects in a rodent model. METHODS: Twenty-four retired male breeder Sprague-Dawley rats were divided into 4 groups of 6 animals. Facial critical-size defects were created by removing the nasalis bones with a bone-cutting drill. Defects were treated with 300 pg of type 1 collagen gel (T1CG), T1CG augmented with 3 microg of IGF-1, T1CG augmented with 3 microg of IGF-2, or T1CG augmented with a combination of 3 microg of IGF-1 and 3 microg of IGF-2. After 30 days the animals were examined at necropsy with precise planimetry, histological analysis of new bone growth, and radiodensitometric analysis of bone thickness. RESULTS: Radiodensitometric measurements showed that IGF-2 augmentation resulted in greatest osseous healing, with measurements being statistically significant over those of all other groups (P\u3c or = .03). Combination IGF-1 and IGF-2 had osseous healing that was intermediate between IGF-1 augmentation and IGF-2 augmentation alone, with measurements being statistically significant over those of unaugmented gels (P CONCLUSION: Collagen gels augmented with IGF significantly enhance the osteoconductive repair of nasal critical-size defects in a rodent model, with IGF-2 showing highest efficacy