The Creation of a low-cost, reliable platform for mobile robotics research

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, June 2011."June 2011." Cataloged from PDF version of thesis.Includes bibliographical references (p. 29).This work documents the planning process, design, fabrication, and integration of a low-cost robot designed for research on the problem of life-long robot mapping. The robotics platform used is the iRobot Create. This robot also employs the PrimeSensor, a sensor with the ability to provide a pixel-matched, colored depth field in real time. This sensor was later purchased by Microsoft and leveraged in their popular gaming device, the Microsoft Kinect. The robot has a powerful Acer Aspire 1830T-6651 laptop with an Intel Core i5 to perform processor-intensive, real-time image processing. The actual construction of the robot consisted of two phases: the physical integration of the components on a chassis and the software integration through the computer. The physical integration is mainly a central chassis made from laser-cut acrylic. This chassis is capable of securely holding the laptop computer in place and provides an elevated mount for the PrimeSensor. This mount has the ability to change the viewing angle of the sensor and lock that angle at 5' increments using a pin. The software integration was completed using open-source packages for the Robot Operating System (ROS) developed by Brown University and a not-for-profit company called OpenNI. These packages were installed on the onboard laptop and the ROS core functions running on the laptop provide the foundation to run new code on this testing platform. This robot is low in cost and provides a reliable, robust, and versatile platform for visionbased artificial intelligence research. The mapping software and vision algorithms developed on this platform will contribute to the development of more intelligent and meaningful vision capabilities for tomorrow's robots.by Taylor Harrison Gilbert.S.B

Evidence for infection and inflammation in infant deaths in a country with historically low incidences of sudden infant death syndrome

Total infant mortality in Hungary has been higher than other European countries; however, the reported incidence of Sudden Infant Death Syndrome (SIDS) has been lower than those of Western Europe and the United States. The low incidence of SIDS in Hungary has been supported by evidence obtained from the high rate of scene of death investigation and medico-legal autopsy mandatory since the 1950s. In this study, we compared the incidence of explained and unexplained infant deaths in Hungary for three periods: 1979-1989 when the incidence of SIDS was high in western Europe; 1990-1999 when the incidence of infant deaths was falling following introduction of the public health campaigns to reduce the risk factors associated with SIDS; 2000-2012 to determine if introduction of Hib or pneumococcal vaccines or introduction of an earlier immunization schedule during this period had an effect on SIDS or SUDI. Explained infant deaths fell consistently during this period; however, unexplained deaths (SIDS) rose during the second period when the incidence of SIDS was falling in other European countries. Evidence for infection and/or inflammation was observed for the majority of SIDS during each period. The results are discussed in relation to campaigns to reduce infant mortality in Hungary and the introduction of new vaccines and an earlier immunization schedule in 2006

An optimized TOPS+ comparison method for enhanced TOPS models

This article has been made available through the Brunel Open Access Publishing Fund.Background Although methods based on highly abstract descriptions of protein structures, such as VAST and TOPS, can perform very fast protein structure comparison, the results can lack a high degree of biological significance. Previously we have discussed the basic mechanisms of our novel method for structure comparison based on our TOPS+ model (Topological descriptions of Protein Structures Enhanced with Ligand Information). In this paper we show how these results can be significantly improved using parameter optimization, and we call the resulting optimised TOPS+ method as advanced TOPS+ comparison method i.e. advTOPS+. Results We have developed a TOPS+ string model as an improvement to the TOPS [1-3] graph model by considering loops as secondary structure elements (SSEs) in addition to helices and strands, representing ligands as first class objects, and describing interactions between SSEs, and SSEs and ligands, by incoming and outgoing arcs, annotating SSEs with the interaction direction and type. Benchmarking results of an all-against-all pairwise comparison using a large dataset of 2,620 non-redundant structures from the PDB40 dataset [4] demonstrate the biological significance, in terms of SCOP classification at the superfamily level, of our TOPS+ comparison method. Conclusions Our advanced TOPS+ comparison shows better performance on the PDB40 dataset [4] compared to our basic TOPS+ method, giving 90 percent accuracy for SCOP alpha+beta; a 6 percent increase in accuracy compared to the TOPS and basic TOPS+ methods. It also outperforms the TOPS, basic TOPS+ and SSAP comparison methods on the Chew-Kedem dataset [5], achieving 98 percent accuracy. Software Availability: The TOPS+ comparison server is available at http://balabio.dcs.gla.ac.uk/mallika/WebTOPS/.This article is available through the Brunel Open Access Publishing Fun

Toward Robust Interpretation of Low‐Temperature Thermochronometers in Magmatic Terranes

Many regions central to our understanding of tectonics and landscape evolution are active or ancient magmatic terranes, and robust interpretation of low‐temperature thermochronologic ages in these settings requires careful attention to the drivers of rock heating and cooling, including magmatism. However, we currently lack a quantitative framework for evaluating the potential role of magmatic cooling—that is, post‐magmatic thermal relaxation—in shaping cooling age patterns in regions with a history of intrusive magmatism. Here we use analytical approximations and numerical models to characterize how low‐temperature thermochronometers document cooling inside and around plutons in steadily exhuming environments. Our models predict that the thermal field a pluton intrudes into, specifically the ambient temperatures relative to the closure temperature of a given thermochronometer, is as important as the pluton size and temperature in controlling the pattern and extent of thermochronometer resetting in the country rocks around a pluton. We identify one advective and several conductive timescales that govern the relationship between the crystallization and cooling ages inside a pluton. In synthetic vertical age‐elevation relationships (AERs), resetting next to plutons results in changes in AER slope that could be misinterpreted as past changes in exhumation rate if the history of magmatism is not accounted for. Finally, we find that large midcrustal plutons, such as those emplaced at ~10–15‐km depth, can reset the low‐temperature thermochronometers far above them in the upper crust—a result with considerable consequences for thermochronology in arcs and regions with a history of magmatic activity that may not have a surface expression.Key PointsIntrusive magmatism may produce important first‐order effects on patterns of low‐temperature thermochronometer coolingAnalytical approximations and numerical models predict cooling ages in and around crustal plutons in steadily exhuming environmentsLarge plutons emplaced in the middle crust at 10–15‐km depth can reset low‐temperature thermochronometers in the upper crustPeer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146628/1/ggge21696.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146628/2/ggge21696_am.pd

Unconventional quantum vortex matter state hosts quantum oscillations in the underdoped high-temperature cuprate superconductors.

A central question in the underdoped cuprates pertains to the nature of the pseudogap ground state. A conventional metallic ground state of the pseudogap region has been argued to host quantum oscillations upon destruction of the superconducting order parameter by modest magnetic fields. Here, we use low applied measurement currents and millikelvin temperatures on ultrapure single crystals of underdoped [Formula: see text] to unearth an unconventional quantum vortex matter ground state characterized by vanishing electrical resistivity, magnetic hysteresis, and nonohmic electrical transport characteristics beyond the highest laboratory-accessible static fields. A model of the pseudogap ground state is now required to explain quantum oscillations that are hosted by the bulk quantum vortex matter state without experiencing sizable additional damping in the presence of a large maximum superconducting gap; possibilities include a pair density wave.Royal Society Winton Programme for the Physics of Sustainability Engineering and Physical Sciences Research Council (EPSRC; studentship and grant numbers EP/R513180/1, EP/M506485/1 and EP/P024947/1) European Research Council under the European Unions Seventh Framework Programme (Grant Agreement numbers 337425 and 772891). EPSRC Strategic Equipment Grant EP/M000524/1 Leverhulme Trust by way of the award of a Philip Leverhulme Prize. National Key Research and Development Program of China (grant no. 2016YFA0401704). Work performed at the National High Magnetic Field Laboratory (NHMFL) supported by NSF Cooperative Agreement DMR-1157490, the State of Florida, and the Department of Energy (DOE) DOE Basic Energy Sciences project: ‘Science of 100 tesla’

Assembling evidence for identifying reservoirs of infection

Many pathogens persist in multihost systems, making the identification of infection reservoirs crucial for devising effective interventions. Here, we present a conceptual framework for classifying patterns of incidence and prevalence, and review recent scientific advances that allow us to study and manage reservoirs simultaneously. We argue that interventions can have a crucial role in enriching our mechanistic understanding of how reservoirs function and should be embedded as quasi-experimental studies in adaptive management frameworks. Single approaches to the study of reservoirs are unlikely to generate conclusive insights whereas the formal integration of data and methodologies, involving interventions, pathogen genetics, and contemporary surveillance techniques, promises to open up new opportunities to advance understanding of complex multihost systems

Violations of fundamental symmetries in atoms and tests of unification theories of elementary particles

High-precision measurements of violations of fundamental symmetries in atoms are a very effective means of testing the standard model of elementary particles and searching for new physics beyond it. Such studies complement measurements at high energies. We review the recent progress in atomic parity nonconservation and atomic electric dipole moments (time reversal symmetry violation), with a particular focus on the atomic theory required to interpret the measurements.Comment: 103 pages, 23 figures; submitted to Physics Reports; comments welcom

Biogeography of mammals in SE Asia: estimates of rates of colonization, extinction and speciation

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75423/1/j.1095-8312.1986.tb01752.x.pd

Sex Differences in Characteristics of Adolescents Presenting to the Emergency Department with Acute Assault‐related Injury

Objectives:  Adolescents with a history of peer assault are known to report high rates of other risky behaviors. The characteristics of adolescents seeking care in the ED for acute assault‐related injury are less well established. This knowledge deficit is particularly noticeable for adolescent female victims of peer assault. This study’s objectives were: 1) to characterize the demographics and risk behaviors of youths presenting to the emergency department (ED) with acute assault‐related injury and 2) to compare assaulted youths’ demographic characteristics, past experiences with violence, and other risk behaviors by sex. Methods:  A systematic sample of adolescents (ages 14 to 18 years) presenting to an urban ED with acute assault‐related injury (excluding dating violence, sexual assault, and child abuse) was recruited. Consenting participants self‐administered a computerized survey about demographics, history of peer and dating aggression, and theoretical correlates of violence (e.g., alcohol and other drug use, depressive symptoms, weapon carriage). Multivariate logistic regression was performed to identify factors that were differentially associated with presentation to the ED for acute assault‐related injury for females versus males. Results:  Of 3,338 adolescents completing a screening survey during the 36‐month study period, 197 had presented to the ED with acute assault‐related injuries; seven of these were excluded from this study due to being victims of dating violence. Most ( n =  179, 94.2%) of these 190 acutely assaulted participants were discharged home. The majority reported a history of past‐year peer aggression ( n =  160, 84.2%) and past‐year violent injury ( n =  106, 55.8%). Similar rates of past‐year peer aggression, past‐year violent injury, alcohol use, and weapon carriage were observed for adolescent males and females presenting with acute assault‐related injury. Males and females also reported similar age, race, socioeconomic status, and education levels. Compared to males, females were less likely to report living with a parent (odds ratio [OR] = 0.25, 95% confidence interval [CI] = 0.08 to 0.84) and were more likely to report depressive symptoms (OR = 2.59, 95% CI = 1.23 to 5.48) and past‐year dating aggression (OR = 2.23, 95% CI = 1.04 to 4.82). Conclusions:  Male and female adolescents with acute assault‐related injuries were very similar. Both reported extremely high rates of past year peer violence, assault‐related injury, and substance use. The greater prevalence of some risk factors among adolescent females, such as depressive symptoms, dating aggression, and independent living status, should be further investigated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/86795/1/j.1553-2712.2011.01165.x.pd