Tensor models and embedded Riemann surfaces

Tensor models and, more generally, group field theories are candidates for higher-dimensional quantum gravity, just as matrix models are in the 2d setting. With the recent advent of a 1/N-expansion for coloured tensor models, more focus has been given to the study of the topological aspects of their Feynman graphs. Crucial to the aforementioned analysis were certain subgraphs known as bubbles and jackets. We demonstrate in the 3d case that these graphs are generated by matrix models embedded inside the tensor theory. Moreover, we show that the jacket graphs represent (Heegaard) splitting surfaces for the triangulation dual to the Feynman graph. With this in hand, we are able to re-express the Boulatov model as a quantum field theory on these Riemann surfaces.Comment: 9 pages, 7 fi

Integrating Spatial Working Memory and Remote Memory: Interactions between the Medial Prefrontal Cortex and Hippocampus

In recent years, two separate research streams have focused on information sharing between the medial prefrontal cortex (mPFC) and hippocampus (HC). Research into spatial working memory has shown that successful execution of many types of behaviors requires synchronous activity in the theta range between the mPFC and HC, whereas studies of memory consolidation have shown that shifts in area dependency may be temporally modulated. While the nature of information that is being communicated is still unclear, spatial working memory and remote memory recall is reliant on interactions between these two areas. This review will present recent evidence that shows that these two processes are not as separate as they first appeared. We will also present a novel conceptualization of the nature of the medial prefrontal representation and how this might help explain this area’s role in spatial working memory and remote memory recall

Positive Polynomials on Riesz Spaces

We prove some properties of positive polynomial mappings between Riesz spaces, using finite difference calculus. We establish the polynomial analogue of the classical result that positive, additive mappings are linear. And we prove a polynomial version of the Kantorovich extension theorem.Comment: 12 page

The solar gamma ray and neutron capabilities of COMPTEL on the Gamma Ray Observatory

The imaging Compton telescope COMPTEL on the Gamma Ray Observatory (GRO) has unusual spectroscopic capabilities for measuring solar gamma-ray and neutron emission. The launch of the GRO is scheduled for June 1990 near the peak of the sunspot cycle. With a 30 to 40 percent probability for the Sun being in the COMPTEL field-of-view during the sunlit part of an orbit, a large number of flares will be observed above the 800 keV gamma-ray threshold of the telescope. The telescope energy range extends to 30 MeV with high time resolution burst spectra available from 0.1 to 10 MeV. Strong Compton tail suppression of instrumental gamma-ray interactions will facilitate improved spectral analysis of solar flare emissions. In addition, the high signal to noise ratio for neutron detection and measurement will provide new neutron spectroscopic capabilities. Specifically, a flare similar to that of 3 June 1982 will provide spectroscopic data on greater than 1500 individual neutrons, enough to construct an unambiguous spectrum in the energy range of 20 to 200 MeV. Details of the instrument and its response to solar gamma-rays and neutrons will be presented

Continuous Theta Rhythm During Spatial Working Memory Task in Rodent Models of Streptozotocin-induced Type 2 Diabetes

Alzheimer’s disease is a neurodegenerative disorder altering memory loss thought to be due to neuropathological symptoms such as the buildup of beta amyloid plaques (Ab) and neurofibrillary tangles (NFT). The etiology of Alzheimer’s is still unknown; however, potential risk factors such as diabetes may lead to its development. The most common form of diabetes is type 2 diabetes known for persistent insulin resistance leading to a state of hyperglycemia. Insulin resistance has been shown to affect cognitive abilities such as learning, memory and also alters synaptic plasticity. Neural connections between the hippocampus (HC) and anterior cingulate cortex (ACC) are known to be very important for learning and memory and are highly plastic, making them an intriguing target that could be altered by hyperglycemia. We hypothesize that hyperglycemic rodents will exhibit spatial memory deficits that may be associated with cognitively linked interactions between the HC and ACC. Minimal doses of streptozotocin (STZ), which is toxic to insulin producing beta cells, were given for 9-10 weeks. Using a spatial working memory task known as delayed alternation we found significant differences between control and experimental rats in working memory accuracy. This task places strong working memory demands on subjects which may be compromised by a hyperglycemic state. We measured EEG recordings from the HC and ACC during task performance and found that hyperglycemic rats had nearly continuous theta rhythm during the 30-minute session. Control rats however, displayed normal transitions between theta and lower frequency delta. Neural connectivity may be altered due to a change in frequency activity between the HC and ACC due to diabetes which is a risk factor in the development of AD impairments. These results show that hyperglycemia leads to changes along the circuit critical for learning and memory

A FOLLOW-UP STUDY OF FIFTY-TWO RICHMOND PUBLIC SCHOOL PUPILS GIVEN PSYCHIATRIC STAFFING DURING THE 1966-1967 SCHOOL YEAR

This research study is a descriptive study of the effectiveness of the psychiatric staffing as determined by a follow-up study of fifty-two Richmond Public School Pupils given such staffing during the l966-67 school year. The review of pertinent literature reveals what others have contributed to the knowledge of the nature and function of the school helping team. The teamwork approach, which involves the efforts of several professions and disciplines working closely together, is seen as the best present method to meet the complex, overlapping needs which have been found to affect students\u27 learning. As a means of establishing guidelines and limits for this study, five areas of concern were defined. The questions to be answered by this study were: 1. What are the socio-economic backgrounds represented by the sample? 2. Were the recommendations made by the school psychiatrist implemented? 3. Is the overall psychiatric staffing effective according to the improvement in pupils presenting problems and the extent to which the recommendations were carried out? 4. To what extent do the available records contain sufficient information for a follow-up study? 5. What are the attitudes of the key persons responsible for the psychiatric staffing toward the effective operation of these staffings? The Pupil Personnel Services gave its approval to conduct this study. The sample numbered fifty-two. The agency requested and it was agreed that no pupil, school, or agency be contacted and that information be obtained only from the files and employees of Pupil Personnel Services. An interview schedule was constructed to elicit information to determine the extent to which the recommendations made during the psychiatric staffing were initiated and carried out. This schedule was applied to the pupil records. Open ended questions were used in interview schedules to gather pertinent information from three key persons responsible for the effective operation of the psychiatric staffing. The fifty-two pupil cases revealed the pupils to be largely from low income families, mostly males with acting-out behavior problems, and with no significant concentration from any one school. A larger percentage of the recommendations that were initiated involved the use of school resources rather than community resources. In nearly half of the pupil cases the recommendations were completely carried out, with a remaining few being carried out to a lesser extent. The findings suggested that, if the recommendations were carried out, the pupil would show behavior improvement. To a large extent the statements made by the key persons generally reflected that methods of record keeping be improved within the Department of Visiting Teachers; that there be an increase in the number and quality of the visiting teachers, especially for elementary and Junior high school placements; that parents of the pupils given psychiatric staffings become involved in the staffings and be included in the treatment process themselves; and that the visiting teacher exercise more responsibility for follow-up on the pupils given psychiatric staffing

Partial breakdown of quantum thermalization in a Hubbard-like model

We study the possible breakdown of quantum thermalization in a model of itinerant electrons on a one-dimensional chain without disorder, with both spin and charge degrees of freedom. The eigenstates of this model exhibit peculiar properties in the entanglement entropy, the apparent scaling of which is modified from a "volume law" to an "area law" after performing a partial, site-wise measurement on the system. These properties and others suggest that this model realizes a new, non-thermal phase of matter, known as a quantum disentangled liquid (QDL). The putative existence of this phase has striking implications for the foundations of quantum statistical mechanics.Comment: As accepted to PR