A multi-stage recurrent neural network better describes decision-related activity in dorsal premotor cortex

We studied how a network of recurrently connected artificial units solve a visual perceptual decision-making task. The goal of this task is to discriminate the dominant color of a central static checkerboard and report the decision with an arm movement. This task has been used to study neural activity in the dorsal premotor (PMd) cortex. When a single recurrent neural network (RNN) was trained to perform the task, the activity of artificial units in the RNN differed from neural recordings in PMd, suggesting that inputs to PMd differed from inputs to the RNN. We expanded our architecture and examined how a multi-stage RNN performed the task. In the multi-stage RNN, the last stage exhibited similarities with PMd by representing direction information but not color information. We then investigated how the representation of color and direction information evolve across RNN stages. Together, our results are a demonstration of the importance of incorporating architectural constraints into RNN models. These constraints can improve the ability of RNNs to model neural activity in association areas.https://doi.org/10.32470/CCN.2019.1123-0Accepted manuscrip

Development's 'downside': social and psychological pathology in countries undergoing social change

Emphasis on the decline in mortality related to infectious disease, the improvement in child survival and the extension in longevity creates an optimistic view of the effects on health of social change. In contrast, attention to behavioural and social problems apparently stemming from current global social transformations leads to a more negative assessment. Specific historical processes shape local worlds of experience so as to yield complex patterns of social change with multiple outcomes. Study should be directed at the specific mediating social and moral processes that yield negative mental-health outcomes in order to develop international mental-health policy to guide prevention, and to control the dangerously destructive effects of specific social transformations, planned as well as unplanned

AIAA Design, Build, Fly: Structures and Controls

For their Santa Clara University Senior Design Project, this team chose to create an unmanned aerial vehicle (UAV) with the intent of participating in the AIAA Design, Build, Fly competition. Divided into two subteams, Aerodynamics and Structures & Controls, the teams worked together to model and construct a working prototype aircraft. The Aerodynamics team focused on selecting adequate airfoil and wing dimensions for the main wing and tail through the use of aircraft design software and CFD simulations. Aiming at a cruise speed of approximately 25 m/s, the team decided that the NACA 4416 airfoil would be the most suitable, with a chord length of 0.3 m and a wingspan of 1.5 m. The Structures & Controls team focused on the integration of the chosen airfoil into a full aircraft assembly, in addition to selection of sub-components for control and propulsion. After considering a balsa wood, carbon sheet, or foam construction, a balsa wood buildup was selected as the ideal manufacturing method to meet the system requirements. Finite element models (FEM) and simulations were preformed to design and analyze the integrity and strength of such a structure under various load cases. For sub-systems a fixed tricycle landing gear set-up was selected to minimize system weight and complexity. For an expected 3.175 kg gross weight with payload, propulsion components were selected based on power requirements established by the Aerodynamics team, consisting of a 2000W 520 Kv brushless DC motor, 22.2 Volt 4,500 mAh LiPo battery, and 15x6E propeller. The control surface actuators chosen were servo motors sized by aerodynamic analysis of the control surfaces. Finally control and transmission components were taken from current inventory including: 2.4 GHz Spektrum DX8 controller and 2.4 GHz X8R receiver. The culmination of this design project resulted in a successful test flight containing a 1 kg payload

Thinking globally, acting locally : investigating local-level capacity in the United States to pursue sustainability

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 1996.Includes bibliographical references (p. [168]-175).by Jonathn I. Kleinman.M.S

Correlates of Parental Antibiotic Knowledge, Demand, and Reported Use

Clinicians cite parental misconceptions and requests for antibiotics as reasons for inappropriate prescribing. To identify misconceptions regarding antibiotics and predictors of parental demand for antibiotics and to determine if parental knowledge and attitudes are associated with use. Survey of parents in 16 Massachusetts communities. Domains included antibiotic-related knowledge, attitudes about antibiotics, antibiotic use during a 12-month period, demographics, and access to health information. Bivariate and multivariate analyses evaluated predictors of knowledge and proclivity to demand antibiotics. A multivariate model evaluated the associations of knowledge, demand, and demographic factors with parent-reported antibiotic use. A total of 1106 surveys were returned (response rates: 54% and 32% for commercially-insured and Medicaid-insured families). Misconceptions were common regarding bronchitis (92%) and green nasal discharge (78%). Two hundred sixty-five (24%) gave responses suggesting a proclivity to demand antibiotics. Antibiotic knowledge was associated with increased parental age and education, having more than 1 child, white race, and receipt of media information on resistance. Factors associated with a proclivity to demand antibiotics included decreased knowledge, pressure from day-care settings, lack of alternatives offered by clinicians, and lack of access to media information. Among all respondents, reported antibiotic use was associated with younger child age and day-care attendance. Among Medicaid-insured children only, less antibiotic knowledge and tendency to demand antibiotics were associated with higher rates of antibiotic use. Misconceptions regarding antibiotic use are widespread and potentially modifiable by clinicians and media sources. Particular attention should be paid to Medicaid-insured patients in whom such misconceptions may contribute to inappropriate prescribing

Child care center policies and practices for management of ill children

OBJECTIVES: The objectives of this study were to 1) describe child care staff knowledge and beliefs regarding upper respiratory tract infections and antibiotic indications and 2) evaluate child care staff reported reasons for a) exclusion from child care, b) referral to a health care provider, and c) recommending antibiotics for an ill child. METHODS: A longitudinal study based in randomly selected child care centers in Massachusetts. Staff completed a survey to assess knowledge regarding common infections. For six weeks, staff completed a record of absences each day, describing the reason for an absence, and advice given to the parents regarding exclusion, referral to a health care provider, and obtaining antibiotics. Exclusions for the specific illness/symptom were defined as appropriate or inappropriate based on national guidelines. RESULTS: A large proportion of child care staff incorrectly believed that antibiotics are indicated for bronchitis (80.5%) and green rhinorrhea (80.5%) in children. For 82.2% of absences, the circumstances or reasons for the absence were discussed with a child care staff member. Of 538 absences due to illness that child care staff discussed with parents, there were 45 inappropriate exclusions (8.4% of illnesses discussed), 91 appropriate exclusions (16.9% of illnesses discussed), and 402 cases (74.7%) in which no recommendation for exclusion was made. CONCLUSIONS: Misconceptions regarding the need for antibiotics for URIs are common among child care staff. However, day care staff do not pressure parents to seek medical attention or antibiotics

A mechanistic multi-area recurrent network model of decision-making

Recurrent neural networks (RNNs) trained on neuroscience-based tasks have been widely used as models for cortical areas performing analogous tasks. However, very few tasks involve a single cortical area, and instead require the coordination of multiple brain areas. Despite the importance of multi-area computation, there is a limited understanding of the principles underlying such computation. We propose to use multi-area RNNs with neuroscience-inspired architecture constraints to derive key features of multi-area computation. In particular, we show that incorpo- rating multiple areas and Dale’s Law is critical for biasing the networks to learn biologically plausible solutions. Additionally, we leverage the full observability of the RNNs to show that output-relevant information is preferentially propagated between areas. These results suggest that cortex uses modular computation to generate minimal sufficient representations of task information. More broadly, our results suggest that constrained multi-area RNNs can produce experimentally testable hypotheses for computations that occur within and across multiple brain areas, enabling new insights into distributed computation in neural systems.https://proceedings.neurips.cc/paper/2021/file/c2f599841f21aaefeeabd2a60ef7bfe8-Paper.pdfPublished versio

Evidence that pneumococcal serotype replacement in Massachusetts following conjugate vaccination is now complete

Invasive pneumococcal disease (IPD) has been reduced in the US following conjugate vaccination (PCV7) targeting seven pneumococcal serotypes in 2000. However, increases in IPD due to other serotypes have been observed, in particular 19A. How much this serotype replacement will erode the benefits of vaccination and over what timescale is unknown. We used a population genetic approach to test first whether the selective impact of vaccination could be detected in a longitudinal carriage sample, and secondly how long it persisted for following introduction of vaccine in 2000. To detect the selective impact of the vaccine we compared the serotype diversity of samples from pneumococcal carriage in Massachusetts children collected in 2001, 2004 and 2007 with others collected in the pre-vaccine era in Massachusetts, the UK and Finland. The 2004 sample was significantly (p \u3e0.0001) more diverse than pre-vaccine samples, indicating the selective pressure of vaccination. The 2007 sample showed no significant difference in diversity from the pre-vaccine period, and exhibited similar population structure, but with different serotypes. In 2007 the carriage frequency of 19A was similar to that of the most common serotype in pre-vaccine samples. We suggest that serotype replacement involving 19A may be complete in Massachusetts due to similarities in population structure to pre-vaccine samples. These results suggest that the replacement phenomenon occurs rapidly with high vaccine coverage, and may allay concerns about future increases in disease due to 19A. For other serotypes, the future course of replacement disease remains to be determined