26 research outputs found
Rapid motion adaptation reveals the temporal dynamics of spatiotemporal correlation between ON and OFF pathways
At the early stages of visual processing, information is processed by two major thalamic pathways encoding brightness increments (ON) and decrements (OFF). Accumulating evidence suggests that these pathways interact and merge as early as in primary visual cortex. Using regular and reverse-phi motion in a rapid adaptation paradigm, we investigated the temporal dynamics of within and across pathway mechanisms for motion processing. When the adaptation duration was short (188 ms), reverse-phi and regular motion led to similar adaptation effects, suggesting that the information from the two pathways are combined efficiently at early-stages of motion processing. However, as the adaption duration was increased to 752 ms, reverse-phi and regular motion showed distinct adaptation effects depending on the test pattern used, either engaging spatiotemporal correlation between the same or opposite contrast polarities. Overall, these findings indicate that spatiotemporal correlation within and across ON-OFF pathways for motion processing can be selectively adapted, and support those models that integrate within and across pathway mechanisms for motion processing
Micronutrient fortification of food and its impact on woman and child health: A systematic review
Background: Vitamins and minerals are essential for growth and metabolism. The World Health Organization estimates that more than 2 billion people are deficient in key vitamins and minerals. Groups most vulnerable to these micronutrient deficiencies are pregnant and lactating women and young children, given their increased demands. Food fortification is one of the strategies that has been used safely and effectively to prevent vitamin and mineral deficiencies.Methods: A comprehensive search was done to identify all available evidence for the impact of fortification interventions. Studies were included if food was fortified with a single, dual or multiple micronutrients and impact of fortification was analyzed on the health outcomes and relevant biochemical indicators of women and children. We performed a meta-analysis of outcomes using Review Manager Software version 5.1.Results: Our systematic review identified 201 studies that we reviewed for outcomes of relevance. Fortification for children showed significant impacts on increasing serum micronutrient concentrations. Hematologic markers also improved, including hemoglobin concentrations, which showed a significant rise when food was fortified with vitamin A, iron and multiple micronutrients. Fortification with zinc had no significant adverse impact on hemoglobin levels. Multiple micronutrient fortification showed non-significant impacts on height for age, weight for age and weight for height Z-scores, although they showed positive trends. The results for fortification in women showed that calcium and vitamin D fortification had significant impacts in the post-menopausal age group. Iron fortification led to a significant increase in serum ferritin and hemoglobin levels in women of reproductive age and pregnant women. Folate fortification significantly reduced the incidence of congenital abnormalities like neural tube defects without increasing the incidence of twinning. The number of studies pooled for zinc and multiple micronutrients for women were few, though the evidence suggested benefit. There was a dearth of evidence for the impact of fortification strategies on morbidity and mortality outcomes in women and children.Conclusion: Fortification is potentially an effective strategy but evidence from the developing world is scarce. Programs need to assess the direct impact of fortification on morbidity and mortality
A many-analysts approach to the relation between religiosity and well-being
The relation between religiosity and well-being is one of the most researched topics in the psychology of religion, yet the directionality and robustness of the effect remains debated. Here, we adopted a many-analysts approach to assess the robustness of this relation based on a new cross-cultural dataset (N=10,535 participants from 24 countries). We recruited 120 analysis teams to investigate (1) whether religious people self-report higher well-being, and (2) whether the relation between religiosity and self-reported well-being depends on perceived cultural norms of religion (i.e., whether it is considered normal and desirable to be religious in a given country). In a two-stage procedure, the teams first created an analysis plan and then executed their planned analysis on the data. For the first research question, all but 3 teams reported positive effect sizes with credible/confidence intervals excluding zero (median reported β=0.120). For the second research question, this was the case for 65% of the teams (median reported β=0.039). While most teams applied (multilevel) linear regression models, there was considerable variability in the choice of items used to construct the independent variables, the dependent variable, and the included covariates
Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades
The most powerful tests of stellar models come from the brightest stars in the sky, for which complementary techniques, such as astrometry, asteroseismology, spectroscopy, and interferometry can be combined. The K2 Mission is providing a unique opportunity to obtain high-precision photometric time series for bright stars along the ecliptic. However, bright targets require a large number of pixels to capture the entirety of the stellar flux, and bandwidth restrictions limit the number and brightness of stars that can be observed. To overcome this, we have developed a new photometric technique, that we call halo photometry, to observe very bright stars using a limited number of pixels. Halo photometry is simple, fast and does not require extensive pixel allocation, and will allow us to use K2 and other photometric missions, such as TESS, to observe very bright stars for asteroseismology and to search for transiting exoplanets. We apply this method to the seven brightest stars in the Pleiades open cluster. Each star exhibits variability; six of the stars show what are most-likely slowly pulsating B-star (SPB) pulsations, with amplitudes ranging from 20 to 2000 ppm. For the star Maia, we demonstrate the utility of combining K2 photometry with spectroscopy and interferometry to show that it is not a 'Maia variable', and to establish that its variability is caused by rotational modulation of a large chemical spot on a 10 d time scale
Beyond the Kepler/K2 bright limit: variability in the seven brightest members of the Pleiades
The most powerful tests of stellar models come from the brightest stars in
the sky, for which complementary techniques, such as astrometry,
asteroseismology, spectroscopy, and interferometry can be combined. The K2
Mission is providing a unique opportunity to obtain high-precision photometric
time series for bright stars along the ecliptic. However, bright targets
require a large number of pixels to capture the entirety of the stellar flux,
and bandwidth restrictions limit the number and brightness of stars that can be
observed. To overcome this, we have developed a new photometric technique, that
we call halo photometry, to observe very bright stars using a limited number of
pixels. Halo photometry is simple, fast and does not require extensive pixel
allocation, and will allow us to use K2 and other photometric missions, such as
TESS, to observe very bright stars for asteroseismology and to search for
transiting exoplanets. We apply this method to the seven brightest stars in the
Pleiades open cluster. Each star exhibits variability; six of the stars show
what are most-likely slowly pulsating B-star (SPB) pulsations, with amplitudes
ranging from 20 to 2000 ppm. For the star Maia, we demonstrate the utility of
combining K2 photometry with spectroscopy and interferometry to show that it is
not a 'Maia variable', and to establish that its variability is caused by
rotational modulation of a large chemical spot on a 10 d time scale
Anatomical variation in the ankle and foot: from incidental finding to inductor of pathology. Part II: midfooot and forefoot
Infant and Young Child Feeding Counseling, Decision-Making, and Practices Among HIV-Infected Women in Malawi’s Option B+ Prevention of Mother-to-Child Transmission Program: A Mixed Methods Study
This study examined infant and young child feeding (IYCF) counseling, decision-making, and practices among HIV-infected women with children 0–23 months participating in Malawi’s Option B+ prevention of mother-to-child transmission (PMTCT) program. We conducted 160 survey interviews, 32 in-depth interviews, and 32 observations of PMTCT visits. Surveys indicated that exclusive breastfeeding was common (75%) among children < 6 months, while minimum dietary diversity (41%) and minimum acceptable diet (40%) for children 6–23 months occurred less often. In-depth interviews supported these findings. Most women felt comfortable with current breastfeeding recommendations, but chronic food insecurity made it difficult for them to follow complementary feeding guidelines. Women trusted IYCF advice from health workers, but mainly received it during pregnancy. During observations of postnatal PMTCT visits, health workers infrequently advised on breastfeeding (41% of visits) or complementary feeding (29% of visits). This represents a missed opportunity for health workers to support optimal IYCF practices within Option B+
Neural mechanisms underlying sensitivity to reverse-phi motion in the fly
Optical illusions provide powerful tools for mapping the algorithms and circuits that underlie visual processing, revealing structure through atypical function. Of particular note in the study of motion detection has been the reverse-phi illusion. When contrast reversals accompany discrete movement, detected direction tends to invert. This occurs across a wide range of organisms, spanning humans and invertebrates. Here, we map an algorithmic account of the phenomenon onto neural circuitry in the fruit fly Drosophila melanogaster. Through targeted silencing experiments in tethered walking flies as well as electrophysiology and calcium imaging, we demonstrate that ON-or OFF-selective local motion detector cells T4 and T5 are sensitive to certain interactions between ON and OFF. A biologically plausible detector model accounts for subtle features of this particular form of illusory motion reversal, like the re-inversion of turning responses occurring at extreme stimulus velocities. In light of comparable circuit architecture in the mammalian retina, we suggest that similar mechanisms may apply even to human psychophysics
