Understanding the role of the primary somatosensory cortex: Opportunities for rehabilitation.

Emerging evidence indicates impairments in somatosensory function may be a major contributor to motor dysfunction associated with neurologic injury or disorders. However, the neuroanatomical substrates underlying the connection between aberrant sensory input and ineffective motor output are still under investigation. The primary somatosensory cortex (S1) plays a critical role in processing afferent somatosensory input and contributes to the integration of sensory and motor signals necessary for skilled movement. Neuroimaging and neurostimulation approaches provide unique opportunities to non-invasively study S1 structure and function including connectivity with other cortical regions. These research techniques have begun to illuminate casual contributions of abnormal S1 activity and connectivity to motor dysfunction and poorer recovery of motor function in neurologic patient populations. This review synthesizes recent evidence illustrating the role of S1 in motor control, motor learning and functional recovery with an emphasis on how information from these investigations may be exploited to inform stroke rehabilitation to reduce motor dysfunction and improve therapeutic outcomes

Atom probe microscopy of zinc isotopic enrichment in ZnO nanorods

We report on atomic probe microscopy (APM) of isotopically enriched ZnO nanorods that measures the spatial distribution of zinc isotopes in sections of ZnO nanorods for natural abundance natZnO and 64Zn and 66Zn enriched ZnO nanorods. The results demonstrate that APM can accurately quantify isotopic abundances within these nanoscale structures. Therefore the atom probe microscope is a useful tool for characterizing Zn isotopic heterostructures in ZnO. Isotopic heterostructures have been proposed for controlling thermal conductivity and also, combined with neutron transmutation doping, they could be key to a novel technology for producing p-n junctions in ZnO thin films and nanorods

Minimizing high spatial frequency residual in active space telescope mirrors

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2008.Includes bibliographical references (p. 141-143).The trend in future space telescopes is towards large apertures and lightweight, rib-stiffened, and actively controlled deformable mirrors. These mirror architectures permit the development of segmented and deployed primary mirrors that lead to tremendous advancement in space telescope performance. Rib-stiffened and discretely actuated deformable mirrors have been shown to effectively mitigate common low order disturbances, but they are inevitably plagued by the "correction limit," or the extent to which the actuators can correct for a given shape disturbance. Improving the correctability of deformable mirrors requires understanding the origins of the correction limit, and optimizing the mirror design accordingly. This thesis details efforts to evaluate the mirror correction limit and the three predominant high spatial frequency mirror surface residual components: actuation-induced dimpling, manufacturing-induced print-through, and disturbance-induced uncorrectable error. The methods for simulating each effect are discussed, and an objective function is developed to quantify the effects of these residual components to gage the performance of each mirror design. A gradient descent algorithm is combined with the parametric capability of the Modular Optical Space Telescope (MOST) modeling tool to allow rapid trade space navigation and optimization of the mirror design across variations in mirror areal density, f-number, structural mass fractions, and rib aspect ratio. These optimization routines yield more advanced design heuristics that improve upon the simplified design techniques that are typical in industry. By forming the heuristics in terms of minimum machinable rib thickness, these new design relationships produce mirrors that satisfy manufacturing constraints and minimize uncorrectable high spatial frequency error.by Thomas Gray.S.M

Scale-free memory model for multiagent reinforcement learning. Mean field approximation and rock-paper-scissors dynamics

A continuous time model for multiagent systems governed by reinforcement learning with scale-free memory is developed. The agents are assumed to act independently of one another in optimizing their choice of possible actions via trial-and-error search. To gain awareness about the action value the agents accumulate in their memory the rewards obtained from taking a specific action at each moment of time. The contribution of the rewards in the past to the agent current perception of action value is described by an integral operator with a power-law kernel. Finally a fractional differential equation governing the system dynamics is obtained. The agents are considered to interact with one another implicitly via the reward of one agent depending on the choice of the other agents. The pairwise interaction model is adopted to describe this effect. As a specific example of systems with non-transitive interactions, a two agent and three agent systems of the rock-paper-scissors type are analyzed in detail, including the stability analysis and numerical simulation. Scale-free memory is demonstrated to cause complex dynamics of the systems at hand. In particular, it is shown that there can be simultaneously two modes of the system instability undergoing subcritical and supercritical bifurcation, with the latter one exhibiting anomalous oscillations with the amplitude and period growing with time. Besides, the instability onset via this supercritical mode may be regarded as "altruism self-organization". For the three agent system the instability dynamics is found to be rather irregular and can be composed of alternate fragments of oscillations different in their properties.Comment: 17 pages, 7 figur

The prevalence of novel psychoactive substances (NPS) use in non-clinical populations: A systematic review protocol

BackgroundNovel psychoactive substances (NPS) are new narcotic or psychotropic drugs that are not controlled by the United Nations drug convention that may pose a serious public health threat due to their wide availability for purchase on the internet and in so called “head shops.” Yet, the extent of their global use remains largely unknown. The aim of this study is to conduct a systematic review of the prevalence of NPS use in non-clinical populations.MethodsThis is a systematic review of observational studies. Embase, MEDLINE, PubMed, Cumulative Index to Nursing and Allied Health (CINAHL), Cochrane Library, Lilacs, Scopus, Global Health, PsychINFO, Web of Science, and the World Health Organization (WHO) regional databases will be searched for eligible prevalence studies published between 2010 and 2016. Data from cross-sectional studies that report the prevalence of NPS use (one or more types) in participants (of any age) from censuses or probabilistic or convenience samples will be included. Data will be extracted from eligible publications, using a data extraction tool developed for this study. Visual and statistical approaches will be adopted instead of traditional meta-analytic approaches.DiscussionThis review will describe the distributions of various types of prevalence estimates of NPS use and explore the impact of different population groups and study-related and tempo-geographical variables on characteristics of these distributions over the period of 2010 to 2016.Systematic review registrationPROSPERO CRD4201603702

Parameter estimation in spatially extended systems: The Karhunen-Loeve and Galerkin multiple shooting approach

Parameter estimation for spatiotemporal dynamics for coupled map lattices and continuous time domain systems is shown using a combination of multiple shooting, Karhunen-Loeve decomposition and Galerkin's projection methodologies. The resulting advantages in estimating parameters have been studied and discussed for chaotic and turbulent dynamics using small amounts of data from subsystems, availability of only scalar and noisy time series data, effects of space-time parameter variations, and in the presence of multiple time-scales.Comment: 11 pages, 5 figures, 4 Tables Corresponding Author - V. Ravi Kumar, e-mail address: [email protected]

Climate-smart fisheries: CO2 emissions reduction and food security are complementary

In the global north, climate-smart fisheries (CSF) policies prioritise steps to combat CO2 emissions from SSF, in a response to the fact that globally, CO2 emissions from small-scale fisheries (SSFs) increased by over 5.8 times between 1950 and 2016. However, in the global south, CSF policies on SSF prioritise food and income security over CO2 emission reduction. In this paper, we examine this apparently contrasting interpretation of CSF as a conceptual framework to interpret the case study of Sierra Leone, one of Africa's poorest countries where we found that small-scale coastal fishers are preoccupied with mitigating the impact of climate change on their food and income security rather than with lowering their CO2 emissions. The self-image of SSF in Sierra Leone is that of being victims of climate change rather than perpetrators of it, and they justify this stance by claiming their livelihoods are being threatened by climate change. However, it could be argued that the best way to keep Sierra Leonean SSF CO2 emissions low is to prioritise their food and income security: in other words, that food security and CO2 reductions are complementary not contradictory. This, at any rate, is the argument of the current paper. The fieldwork for this study entailed co-created research in Sierra Leone and it involved 103 stakeholders who met face-to-face and online between January and March 2022 and through village meetings. The results of this fieldwork showed that food and income security and not CO2 emissions are the priorities in the stakeholders’ interpretation of CSF. However, if food and income security are not prioritised, communities are likely to adopt maladaptive strategies which undermine marine protected areas (MPAs) and exacerbate overfishing, thereby increasing CO2 emissions. Moreover, investment in aquaculture as a supplementary or alternative livelihood can directly increase food security and incomes and at the same time indirectly serve as a CO2 mitigation measure. In addition, weather information communication is an important CSF measure which both protects fishers from the impact of climate change and reduces their CO2 emissions. Accordingly, we argue that the contrast between reducing CO2 emissions and protecting food security from climate change may be more apparent than real in Sierra Leone coastal fisheries, since both policies may work in tandem together. This study therefore contributes a new interpretation of CSF in the global south: instead of seeing it as posing a conflict between CO2 emissions reductions and food security, we have shown the two objectives can be complementary. The wider implication of this paper is that CSF strategies for SSFs do not have to be polarised between the global north's focus on the reduction of CO2 emissions from fishing vessels and the global south's focus on the mitigation of the impact of global warming on SSFs. There are circumstances when the two objectives may be in harmony

Starting the Conversation: Are Campus Sexual Assault Policies Related to the Prevalence of Campus Sexual Assault?

One goal of university campus sexual assault (CSA) policies is to help prevent CSA. Federal guidance in the 2014 White House Task Force to Protect Students From Sexual Assault Checklist for Campus Sexual Misconduct Policies suggests 10 elements for inclusion in CSA policies (e.g., Policy Introduction, Grievance/Adjudication), and outlines policy topics to be included within each element (Policy Introduction includes two topics: statement of prohibition against sex discrimination including sexual misconduct and statement of commitment to address sexual misconduct). However, no research has examined whether CSA policies impact CSA prevalence. To begin addressing this gap, we studied 24 universities participating in the 2015 Association of American Universities Campus Climate Survey on Sexual Assault and Sexual Misconduct. We linked 2014-2015 data from these universities’ CSA policies and their CSA prevalence findings from the 2015 Association of American Universities (AAU) survey. To test whether the comprehensiveness of schools’ CSA policies was related to schools’ CSA prevalence, we examined the degree to which the CSA policies included recommended policy content from the aforementioned Checklist. Policies were characterized as more comprehensive if they included greater numbers of Checklist topics. We then correlated the number of topics within the policies with school-level CSA prevalence. We also explored whether there was lower CSA prevalence among schools with policies containing particular topics. Results suggested that greater comprehensiveness of schools’ entire CSA policies was negatively correlated with CSA prevalence; however, these findings did not approach statistical significance. The number of negative correlations observed between schools’ CSA policy elements and CSA prevalence among undergraduate women was greater than expected by chance alone, suggesting a possible connection between comprehensive CSA policies and CSA prevalence. Schools with policies that included a topic on their sexual assault response team had the lowest CSA prevalence for both women and men, and schools that included topics describing grievance/adjudication procedures had lower CSA prevalence. This study provides a novel examination of CSA and could inform needed research related to the impact of CSA policies on CSA