Issues in Exploring Variation in Childhood Socioeconomic Gradients By Age: A Response to Case, Paxson, and Vogl.

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/116220/1/ssm07.pd

Structure, function, and cortical representation of the rat submandibular whisker trident

© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Journal of Neuroscience 33 (2013): 4815-4824, doi:10.1523/JNEUROSCI.4770-12.2013.Although the neurobiology of rodent facial whiskers has been studied intensively, little is known about sensing in other vibrissae. Here we describe the under-investigated submandibular “whisker trident” on the rat's chin. In this three-whisker array, a unique unpaired midline whisker is laterally flanked by two slightly shorter whiskers. All three whiskers point to the ground and are curved backwards. Unlike other whiskers, the trident is not located on an exposed body part. Trident vibrissae are not whisked and do not touch anything over long stretches of time. However, trident whiskers engage in sustained ground contact during head-down running while the animal is exploring or foraging. In biomechanical experiments, trident whiskers follow caudal ground movement more smoothly than facial whiskers. Remarkably, deflection angles decrease with increasing ground velocity. We identified one putative trident barrel in the left somatosensory cortex and two barrels in the right somatosensory cortex. The elongated putative trident-midline barrel is the longest and largest whisker barrel, suggesting that the midline trident whisker is of great functional significance. Cortical postsynaptic air-puff responses in the trident representation show much less temporal precision than facial whisker responses. Trident whiskers do not provide as much high-resolution information about object contacts as facial whiskers. Instead, our observations suggest an idiothetic function: their biomechanics allow trident whiskers to derive continuous measurements about ego motion from ground contacts. The midline position offers unique advantages in sensing heading direction in a laterally symmetric manner. The changes in trident deflection angle with velocity suggest that trident whiskers might function as a tactile speedometer.This work was supported by the Marine Biological Laboratory, the National Institute of Mental Health (Training Grant 5R25MH059472), Humboldt Universita¨t zu Berlin, the Bernstein Center for Computational Neuroscience Berlin, the German Federal Ministry of Education and Research (Fo¨rderkennzeichen 01GQ1001A), the Deutsche Forschungsgemeinschaft (EXC 257, Neurocure), and the European Research Council (grant to M.B.). M.L.W. was supported by a National Research Service Award from National Institute of Neurological Disorders and Stroke (1F31NS077847).2013-09-1

College completion predicts lower depression but higher metabolic syndrome among disadvantaged minorities in young adulthood

College graduates enjoy healthier, longer lives compared with individuals who do not graduate from college. However, the health benefit of educational attainment is not as great for blacks as it is for whites. Moreover, college completion may not erase the detrimental effects of early-life disadvantage for blacks and Hispanics. We use nationally representative data on young adults to test whether American minorities experience differential returns to educational attainment. We find that college completion predicts lower rates of depression for all racial groups. It also predicts lower metabolic syndrome among whites. However, college completion predicts higher metabolic syndrome among black and Hispanic adults from disadvantaged backgrounds, suggesting upward mobility may come at a health cost to young minorities in America

Natural models for evolution on networks

Evolutionary dynamics has been traditionally studied in the context of homogeneous populations, mainly described by the Moran process [P. Moran, Random processes in genetics, Proceedings of the Cambridge Philosophical Society 54 (1) (1958) 60–71]. Recently, this approach has been generalized in [E. Lieberman, C. Hauert, M.A. Nowak, Evolutionary dynamics on graphs, Nature 433 (2005) 312–316] by arranging individuals on the nodes of a network (in general, directed). In this setting, the existence of directed arcs enables the simulation of extreme phenomena, where the fixation probability of a randomly placed mutant (i.e., the probability that the offspring of the mutant eventually spread over the whole population) is arbitrarily small or large. On the other hand, undirected networks (i.e., undirected graphs) seem to have a smoother behavior, and thus it is more challenging to find suppressors/amplifiers of selection, that is, graphs with smaller/greater fixation probability than the complete graph (i.e., the homogeneous population). In this paper we focus on undirected graphs. We present the first class of undirected graphs which act as suppressors of selection, by achieving a fixation probability that is at most one half of that of the complete graph, as the number of vertices increases. Moreover, we provide some generic upper and lower bounds for the fixation probability of general undirected graphs. As our main contribution, we introduce the natural alternative of the model proposed in [E. Lieberman, C. Hauert, M.A. Nowak, Evolutionary dynamics on graphs, Nature 433 (2005) 312–316]. In our new evolutionary model, all individuals interact simultaneously and the result is a compromise between aggressive and non-aggressive individuals. We prove that our new model of mutual influences admits a potential function, which guarantees the convergence of the system for any graph topology and any initial fitness vector of the individuals. Furthermore, we prove fast convergence to the stable state for the case of the complete graph, as well as we provide almost tight bounds on the limit fitness of the individuals. Apart from being important on its own, this new evolutionary model appears to be useful also in the abstract modeling of control mechanisms over invading populations in networks. We demonstrate this by introducing and analyzing two alternative control approaches, for which we bound the time needed to stabilize to the “healthy” state of the system

FogROS2-SGC: A ROS2 Cloud Robotics Platform for Secure Global Connectivity

The Robot Operating System (ROS2) is the most widely used software platform for building robotics applications. FogROS2 extends ROS2 to allow robots to access cloud computing on demand. However, ROS2 and FogROS2 assume that all robots are locally connected and that each robot has full access and control of the other robots. With applications like distributed multi-robot systems, remote robot control, and mobile robots, robotics increasingly involves the global Internet and complex trust management. Existing approaches for connecting disjoint ROS2 networks lack key features such as security, compatibility, efficiency, and ease of use. We introduce FogROS2-SGC, an extension of FogROS2 that can effectively connect robot systems across different physical locations, networks, and Data Distribution Services (DDS). With globally unique and location-independent identifiers, FogROS2-SGC securely and efficiently routes data between robotics components around the globe. FogROS2-SGC is agnostic to the ROS2 distribution and configuration, is compatible with non-ROS2 software, and seamlessly extends existing ROS2 applications without any code modification. Experiments suggest FogROS2-SGC is 19x faster than rosbridge (a ROS2 package with comparable features, but lacking security). We also apply FogROS2-SGC to 4 robots and compute nodes that are 3600km apart. Videos and code are available on the project website https://sites.google.com/view/fogros2-sgc.Comment: 9 pages, 8 figure

ICT Competencies in Eight Mayan-speaking Communities of Mexico: Preliminary Findings

The skills related to the use of information and communication technologies (ICT) were examined in this study within the context of eight communities with a high degree of vulnerability and diversity. The objectives of the study were: a) to conduct a diagnosis of thirteen competencies related to the use of ICT in eight Mayan-speaking communities in the state of Yucatan, Mexico, and b) to examine such variables as gender, marital status, and the education level of their parents. in relation to the degree of ICT among these youth. The findings indicate that there are differences in the use of technology among the eight communities that participated in the study. Specifically, it was found that the greatest social inequality associates to the lowest performance in the thirteen skills related to ICT. Research also discovered that gender and the marital status of the subjects, as well as the schooling of their parents, related to the ICT competencies. The findings of the study will add more values to ICT related research, especially in the socioeconomic status of the indigenous community and/or some of their personal backgrounds. It could also be used to design training strategies to overcome the most pressing needs of the subjects in the area of ICT

Gender Differences Relative to Smoking Behavior and Emissions of Toxins from Mainstream Cigarette Smoke

This study examined whether gender differences exist in the exposure to select mainstream cigarette smoke toxins as a result of differences in smoking behavior or type of cigarettes smoked among 129 female and 128 male smokers. Smoking topography data indicated that, compared with men, women took smaller puffs (37.6 ml/puff vs. 45.8 ml/puff; p = .0001) of shorter duration (1.33 s/puff vs. 1.48 s/puff; p = .002) but drew more puffs per cigarette (13.5 vs. 12.0; p = .001) and left longer butts (36.3 mm or 40.2% of cigarette length vs. 34.3 mm or 39.2% of cigarette length; p = .01). These trends were similar in both African Americans and European Americans. The emissions of select toxins per cigarette, as determined by mimicking human smoking behaviors were greater among the male smokers than the female smokers and correlated significantly with delivered smoke volume per cigarette. The geometric means of emissions of nicotine from cigarettes were 1.92 mg/cigarette (95% CI = 1.80-2.05) for women versus 2.20 (95% CI = 2.04-2.37) for men (p = .005). Cigarettes smoked by women yielded 139.5 ng/cigarette of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK; 95% CI = 128.8-151.0), compared with 170.3 ng/cigarette (95% CI = 156.3-185.6) for men (p = .0007); benzo(a)pyrene (BaP) emissions were 18.0 ng/cigarette (95% CI = 17.0-19.0) for women and 20.5 ng/cigarette (95% CI = 18.8-22.3) for men (p = .01). The gender differences with regard to cigarette smoke yields of toxins were more profound in European Americans than in African Americans. On average, African American men's smoking habits produced the highest emissions of select toxins from cigarettes, and European American female smokers had the lowest exposure to carcinogens and toxins. Several studies have suggested that women may be more susceptible than men to the ill effects of carcinogens in tobacco and tobacco smoke, whereas other studies have not found differences in lung cancer risk between men and women. The present study suggests that gender differences in exposure to tobacco smoke cannot account for a higher rate of lung cancer in female smokers compared with male smokers