344 research outputs found
A guided tour of asynchronous cellular automata
Research on asynchronous cellular automata has received a great amount of
attention these last years and has turned to a thriving field. We survey the
recent research that has been carried out on this topic and present a wide
state of the art where computing and modelling issues are both represented.Comment: To appear in the Journal of Cellular Automat
Secondary left ventricular injury with haemopericardium caused by a rib fracture after blunt chest trauma
Trauma is the third most common cause of death in the West. In the US, approximately 90,000 deaths annually are traumatic in nature and over 75% of casualties from blunt trauma are due to chest injuries. Cardiac injuries from rib fractures following blunt trauma are extremely rare. We report the unusual case of a patient who fell from a height and presented with haemopericardium and haemothorax as a result of left ventricular and lingular lacerations and was sucessfully operated upon
Overview
The part of Africa designated as West Africa is made up of 16 countries—
Benin, Burkina Faso, Cape Verde, Côte d’Ivoire, Gambia, Ghana,
Guinea, Guinea-Bissau, Liberia, Mali, Mauritania, Niger, Nigeria,
Senegal, Sierra Leone, and Togo. Its land area is about 5 million square kilometers,
and its population in 2010 was about 290 million. With the exception
of Mauritania, these countries are members of the Economic Community of
West African States (ECOWAS). The subregion comprises a diversified agricultural
base spread over a wide range of agroecological zones with significant
potential for improved agricultural productivity.
Agriculture is the major source of livelihood for the majority of West
Africans. The agricultural sector employs 60 percent of the active labor force
but contributes only 35 percent of gross domestic product (GDP). The disparity
between contribution to GDP and share of population means that
many West African farmers are very poor, producing close to subsistence levels
and facing numerous constraints such as droughts, soil acidity, and nutrientdepleted
and degraded soils that impinge on agricultural development. The
most important foodcrops grown and consumed in West Africa are cereals—
sorghum, millet, maize, and rice; roots and tubers—cassava, sweet potatoes,
and yams; and legumes—cowpeas and groundnuts. Major cash crops are
cocoa, coffee, and cotton..
Summary and conclusions
Climate variability is a reality that is affecting rural livelihoods in West
Africa today and presenting a growing challenge in the region, as in many
other parts of the African continent and elsewhere. Climate change will
have far-reaching consequences for the poor and marginalized groups among
which the majority depend on agriculture for their livelihoods and have a
lower capacity to adapt. Weather-related crop failures, fishery collapses, and
livestock deaths in addition to losses of property are already causing economic
losses and undermining food security in West Africa. This situation is likely
to become more desperate and to threaten the survival of the majority of poor
farmers as global warming continues. Feeding the increasing populations in
a subregion with one of the highest rates of population growth in the world
requires radical transformation of a largely underdeveloped agriculture over
the next four decades. A major challenge is increasing agricultural production
among resource-poor farmers without exacerbating environmental problems
and simultaneously coping with climate change..
Internal states as a source of subject-dependent movement variability and their representation by large-scale networks
AbstractA human’s ability to adapt and learn relies on reflecting on past performance. Such reflections form latent factors called internal states that induce variability of movement and behavior to improve performance. Internal states are critical for survival, yet their temporal dynamics and neural substrates are less understood. Here, we link internal states with motor performance and neural activity using state-space models and local field potentials captured from depth electrodes in over 100 brain regions. Ten human subjects performed a goal-directed center-out reaching task with perturbations applied to random trials, causing subjects to fail goals and reflect on their performance. Using computational methods, we identified two internal states, indicating that subjects kept track of past errors and perturbations, that predicted variability in reaction times and speed errors. These states granted access to latent information indicative of how subjects strategize learning from trial history, impacting their overall performance. We further found that large-scale brain networks differentially encoded these internal states. The dorsal attention network encoded past errors in frequencies above 100 Hz, suggesting a role in modulating attention based on tracking recent performance in working memory. The default network encoded past perturbations in frequencies below 15 Hz, suggesting a role in achieving robust performance in an uncertain environment. Moreover, these networks more strongly encoded internal states and were more functionally connected in higher performing subjects, whose learning strategy was to respond by countering with behavior that opposed accumulating error. Taken together, our findings suggest large-scale brain networks as a neural basis of strategy. These networks regulate movement variability, through internal states, to improve motor performance.Key pointsMovement variability is a purposeful process conjured up by the brain to enable adaptation and learning, both of which are necessary for survival.The culmination of recent experiences—collectively referred to as internal states—have been implicated in variability during motor and behavioral tasks.To investigate the utility and neural basis of internal states during motor control, we estimated two latent internal states using state-space representation that modeled motor behavior during a goal-directed center-out reaching task in humans with simultaneous whole-brain recordings from intracranial depth electrodes.We show that including these states—based on error and environment uncertainty—improves the predictability of subject-specific variable motor behavior and reveals latent information related to task performance and learning strategies where top performers counter error scaled by trial history while bottom performers maintain error tendencies.We further show that these states are encoded by the large-scale brain networks known as the dorsal attention network and default network in frequencies above 100 Hz and below 15 Hz but found neural differences between subjects where network activity closely modulates with states and exhibits stronger functional connectivity for top performers.Our findings suggest the involvement in large-scale brain networks as a neural basis of motor strategy that orchestrates movement variability to improve motor performance.</jats:list-item
Holes in the Glycan Shield of the Native HIV Envelope Are a Target of Trimer-Elicited Neutralizing Antibodies
A major advance in the search for an HIV vaccine has been the development of a near-native Envelope trimer (BG505 SOSIP.664) that can induce robust autologous Tier 2 neutralization. Here, potently neutralizing monoclonal antibodies (nAbs) from rabbits immunized with BG505 SOSIP.664 are shown to recognize an immunodominant region of gp120 centered on residue 241. Residue 241 occupies a hole in the glycan defenses of the BG505 isolate, with fewer than 3% of global isolates lacking a glycan site at this position. However, at least one conserved glycan site is missing in 89% of viruses, suggesting the presence of glycan holes in most HIV isolates. Serum evidence is consistent with targeting of holes in natural infection. The immunogenic nature of breaches in the glycan shield has been under-appreciated in previous attempts to understand autologous neutralizing antibody responses and has important potential consequences for HIV vaccine design
Reconfiguring ruins: Beyond Ruinenlust
What explains the global proliferation of interest in ruins? Can ruins be understood beyond their common framing as products of European Romanticism? Might a transdisciplinary approach allow us to see ruins differently? These questions underpinned the Arts and Humanities Research Council–funded project Reconfiguring Ruins, which deployed approaches from history, literature, East Asian studies, and geography to reflect on how ruins from different historical contexts are understood by reference to different theoretical frameworks. In recognition of the value of learning from other models of knowledge production, the project also involved a successful collaboration with the Museum of London Archaeology and the artist-led community The NewBridge Project in Newcastle. By bringing these varied sets of knowledges to bear on the project’s excavations of specific sites in the United Kingdom, the United States, and Japan, the article argues for an understanding of ruins as thresholds, with ruin sites providing unique insights into the relationship between lived pasts, presents, and futures. It does so by developing three key themes that reflect on the process of working collaboratively across the arts, humanities, and social sciences, including professional archaeology: inter- and transdisciplinarity, the limits of cocreation, and traveling meanings and praxis. Meanings of specific ruins are constructed out of specific languages and cultural resonances and read though different disciplines, but can also be reconfigured through concepts and practices that travel beyond disciplinary, cultural, and linguistic borders. As we show here, the ruin is, and should be, a relational concept that moves beyond the romantic notion of Ruinenlust
Sanitation of blackwater via sequential wetland and electrochemical treatment
The discharge of untreated septage is a major health hazard in countries that lack sewer systems and centralized sewage treatment. Small-scale, point-source treatment units are needed for water treatment and disinfection due to the distributed nature of this discharge, i.e., from single households or community toilets. In this study, a high-rate-wetland coupled with an electrochemical system was developed and demonstrated to treat septage at full scale. The full-scale wetland on average removed 79 +/- 2% chemical oxygen demand (COD), 30 +/- 5% total Kjeldahl nitrogen (TKN), 58 +/- 4% total ammoniacal nitrogen (TAN), and 78 +/- 4% orthophosphate. Pathogens such as coliforms were not fully removed after passage through the wetland. Therefore, the wetland effluent was subsequently treated with an electrochemical cell with a cation exchange membrane where the effluent first passed through the anodic chamber. This lead to in situ chlorine or other oxidant production under acidifying conditions. Upon a residence time of at least 6 h of this anodic effluent in a buffer tank, the fluid was sent through the cathodic chamber where pH neutralization occurred. Overall, the combined system removed 89 +/- 1% COD, 36 +/- 5% TKN, 70 +/- 2% TAN, and 87 +/- 2% ortho-phosphate. An average 5-log unit reduction in coliform was observed. The energy input for the integrated system was on average 16 +/- 3 kWh/m(3), and 11 kWh/m(3) under optimal conditions. Further research is required to optimize the system in terms of stability and energy consumption
Comparative proteomic profiling reveals mechanisms for early spinal cord vulnerability in CLN1 disease
CLN1 disease is a fatal inherited neurodegenerative lysosomal storage disease of early childhood, caused by mutations in the CLN1 gene, which encodes the enzyme Palmitoyl protein thioesterase-1 (PPT-1). We recently found significant spinal pathology in Ppt1-deficient (Ppt1−/−) mice and human CLN1 disease that contributes to clinical outcome and precedes the onset of brain pathology. Here, we quantified this spinal pathology at 3 and 7 months of age revealing significant and progressive glial activation and vulnerability of spinal interneurons. Tandem mass tagged proteomic analysis of the spinal cord of Ppt1−/−and control mice at these timepoints revealed a significant neuroimmune response and changes in mitochondrial function, cell-signalling pathways and developmental processes. Comparing proteomic changes in the spinal cord and cortex at 3 months revealed many similarly affected processes, except the inflammatory response. These proteomic and pathological data from this largely unexplored region of the CNS may help explain the limited success of previous brain-directed therapies. These data also fundamentally change our understanding of the progressive, site-specific nature of CLN1 disease pathogenesis, and highlight the importance of the neuroimmune response. This should greatly impact our approach to the timing and targeting of future therapeutic trials for this and similar disorders
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