Sensitivity to Hand Path Curvature during Reaching

People optimize reaching to make straight and smooth movements. We performed experiments characterizing human sensitivity to hand path deviations from a straight reach. Vision of the arm was blocked. Subjects either moved the hand along paths of constrained curvature, or a robot moved the relaxed limb along similar trajectories (active and passive conditions, respectively). Subjects responded after each trial whether or not they thought the movement curved convex right. In a series of three experiments, we tested the effects of modifying visual feedback of hand position to suppress curvature, isotonic muscle activation, and a distracter task on subjects ability to detect curvature during reaching. We found that both active reaching and artificial minimization of visual hand path deviations significantly decreased proprioceptive curvature sensitivity. Specifically, isotonic contraction of muscles antagonistic to the movement decreased sensitivity to curvature while agonistic contraction had no effect. The distracter task did not significantly affect proprioceptive sensitivity, though it did interfere with the detrimental effect of minimizing visual error feedback. These findings demonstrate that: 1) antagonist muscle activation decreases efficacy of proprioceptive feedback during hand path curvature estimation, and 2) vision\u27s dominance over proprioception can be manipulated by altering the attentional demands of the task

Visual, Motor and Attentional Influences on Proprioceptive Contributions to Perception of Hand Path Rectilinearity during Reaching

We examined how proprioceptive contributions to perception of hand path straightness are influenced by visual, motor and attentional sources of performance variability during horizontal planar reaching. Subjects held the handle of a robot that constrained goal-directed movements of the hand to the paths of controlled curvature. Subjects attempted to detect the presence of hand path curvature during both active (subject driven) and passive (robot driven) movements that either required active muscle force production or not. Subjects were less able to discriminate curved from straight paths when actively reaching for a target versus when the robot moved their hand through the same curved paths. This effect was especially evident during robot-driven movements requiring concurrent activation of lengthening but not shortening muscles. Subjects were less likely to report curvature and were more variable in reporting when movements appeared straight in a novel “visual channel” condition previously shown to block adaptive updating of motor commands in response to deviations from a straight-line hand path. Similarly, compromised performance was obtained when subjects simultaneously performed a distracting secondary task (key pressing with the contralateral hand). The effects compounded when these last two treatments were combined. It is concluded that environmental, intrinsic and attentional factors all impact the ability to detect deviations from a rectilinear hand path during goal-directed movement by decreasing proprioceptive contributions to limb state estimation. In contrast, response variability increased only in experimental conditions thought to impose additional attentional demands on the observer. Implications of these results for perception and other sensorimotor behaviors are discussed

Characterization of the Ren4 resistance locus through the integration of de novo assembly, expression analysis, and Genotyping-by-Sequencing data

Internationally, grape breeders have been using traditional breeding approaches to introgress Ren4 resistance against powdery mildew (Erysiphe necator) from a wild Asian grapevine (Vitis romanetii) into cultivated grapevines (V. vinifera). The goal of this work was to use genomic tools to identify candidate genes underlying the Ren4 resistance phenotype. Full- and half-sib families segregating for Ren4 resistance were analyzed using Genotyping-by-Sequencing (GBS), and 70 GBS tags were identified as specifically tagging the Ren4 locus. These tags were used to identify BAC clones at the locus, and a scaffolded BAC assembly was generated using Velvet and SSPACE. This assembly spanned 13.7Mb, and predominately aligned with the correct chromosomal region of the PN40024 reference genome. Two de novo transcriptomes were generated using Trinity for the wild source of Ren4 and a Ren4 introgression line. RNA-seq expression analysis of F1 full-sibling progeny identify candidate genes, 29 of which aligned to the BAC assembly. The integration of these diverse genomic technologies resulted in the identification of 7 Ren4 candidate genes, and the correctness of analyses was independently confirmed by cloning and Sanger sequencing of candidate genes. The integration of these novel approaches accelerated the characterization of the Ren4 locus, and will enhance the genetic improvement of grapevine via marker-assisted breeding or biotechnology

Project MSSE: Maternal Sleep and Social Environment in the Short-Term Postpartum

The postpartum period is a time of considerable excitement and joy for new mothers as well as stress and change. While the majority of postpartum research has been conducted during the first three postpartum months, less is known about how to promote health and minimize maternal risk during the Short-Term Postpartum (3-6 months postpartum). This is an important time-frame of investigation as many U.S. women return to an employment setting during this time while integrating the existing demands of infant care. Accordingly, the current study sought to identify modifiable factors in the Short-Term Postpartum social environment that could enhance maternal well-being and sleep. Seven days of daily social interaction diaries, sleep diaries and actigraphy were collected from 54 healthy, non-depressed, first-time mothers in in the Short-Term Postpartum. Multilevel modeling analyses revealed that daily fluctuation in frequency and valence of social interactions were related to nighttime sleep indices. In addition, improvements in nightly Sleep Quality, specifically, appeared to promote improvements in next-day maternal well-being and protect mothers from the negative effects of social discord. Group differences by employment status were examined; however, the majority of significant relationships were driven by within-person differences thereby supporting the need for examining within-person differences when making recommendations for enhancing maternal sleep and well-being in the postpartum

Assessing the Influencing Factors on the Accuracy of Underage Facial Age Estimation

Swift response to the detection of endangered minors is an ongoing concern for law enforcement. Many child-focused investigations hinge on digital evidence discovery and analysis. Automated age estimation techniques are needed to aid in these investigations to expedite this evidence discovery process, and decrease investigator exposure to traumatic material. Automated techniques also show promise in decreasing the overflowing backlog of evidence obtained from increasing numbers of devices and online services. A lack of sufficient training data combined with natural human variance has been long hindering accurate automated age estimation -- especially for underage subjects. This paper presented a comprehensive evaluation of the performance of two cloud age estimation services (Amazon Web Service's Rekognition service and Microsoft Azure's Face API) against a dataset of over 21,800 underage subjects. The objective of this work is to evaluate the influence that certain human biometric factors, facial expressions, and image quality (i.e. blur, noise, exposure and resolution) have on the outcome of automated age estimation services. A thorough evaluation allows us to identify the most influential factors to be overcome in future age estimation systems

Probing upper thermospheric neutral densities at Mars using electron reflectometry

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95666/1/grl20594.pd

Enhanced ionization of the Martian nightside ionosphere during solar energetic particle events

Electron densities in the Martian nightside ionosphere are more than 90% of time too low to be detected by the Mars Advanced Radar for Subsurface and Ionosphere Sounding radar sounder on board the Mars Express spacecraft. However, the relative number of ionograms with peak electron density high enough to be detected represents a good statistical proxy of the ionospheric density. We focus on solar energetic particle (SEP) events, and we analyze their effects on ionospheric formation. SEP time intervals were identified in situ using the background counts recorded by the ion sensor of the ASPERA-3 instrument on board Mars Express. We show that peak electron densities during the SEP events are large enough to be detected in more than 30% of measurements, and, moreover, the reflections of the sounding signal from the ground almost entirely disappear. Nightside electron densities during SEP events are thus substantially increased as compared to normal nightside conditions

Making judgements about students making work : lecturers’ assessment practices in art and design.

This research study explores the assessment practices in two higher education art and design departments. The key aim of this research was to explore art and design studio assessment practices as lived by and experienced by art and design lecturers. This work draws on two bodies of pre existing research. Firstly this study adopted innovative methodological approaches that have been employed to good effect to explore assessment in text based subjects (think aloud) and moderation mark agreement (observation). Secondly the study builds on existing research into the assessment of creative practice. By applying thinking aloud methodologies into a creative practice assessment context the authors seek to illuminate the ‘in practice’ rather than espoused assessment approaches adopted. The analysis suggests that lecturers in the study employed three macro conceptions of quality to support the judgement process. These were; the demonstration of significant learning over time, the demonstration of effective studentship and the presentation of meaningful art/design work

Comparative study of the Martian suprathermal electron depletions based on Mars Global Surveyor, Mars Express and Mars Atmosphere and Volatile EvolutioN missions observations

Nightside suprathermal electron depletions have been observed at Mars by three spacecraft to date: Mars Global Surveyor, Mars Express, and the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. This spatial and temporal diversity of measurements allows us to propose here a comprehensive view of the Martian electron depletions through the first multispacecraft study of the phenomenon. We have analyzed data recorded by the three spacecraft from 1999 to 2015 in order to better understand the distribution of the electron depletions and their creation mechanisms. Three simple criteria adapted to each mission have been implemented to identify more than 134,500 electron depletions observed between 125 and 900 km altitude. The geographical distribution maps of the electron depletions detected by the three spacecraft confirm the strong link existing between electron depletions and crustal magnetic field at altitudes greater than ~170 km. At these altitudes, the distribution of electron depletions is strongly different in the two hemispheres, with a far greater chance to observe an electron depletion in the Southern Hemisphere, where the strongest crustal magnetic sources are located. However, the unique MAVEN observations reveal that below a transition region near 160–170 km altitude the distribution of electron depletions is the same in both hemispheres, with no particular dependence on crustal magnetic fields. This result supports the suggestion made by previous studies that these low-altitudes events are produced through electron absorption by atmospheric CO2

Evaluating Evidence for the Role of Sleep in Fibromyalgia: A Test of the Sleep and Pain Diathesis Model

The Sleep and Pain Diathesis (SAPD) Model predicts that sleep quality is related to Fibromylagia (FM) outcomes such as disability and depression and that these relationships are mediated by both pain and impaired emotional dysregulation. The purpose of this paper is to provide a preliminary test of this model using cross-sectional data. 35 adult women, who had been living with FM for an average of 13 years, completed a battery of questionnaires that included reports of pain, sleep, affect, and disability. Consistent with this model, FM patients who reported more disrupted sleep also reported higher levels of psychological disability (i.e., BDI depression symptoms) and physical disability. Moreover, the trajectory of the relationship between sleep and pain appears to be mediated by cognitive processes such as increased pain helplessness and, thus, the relationship between sleep and disability appears to be mediated via pain. These data are consistent with the SAPD model, and lend support for the need to include sleep related factors as a critical contributor to our understanding of FM