Problems Affecting Labor

Much experimental work has been devoted in comparing the folding behavior of proteins sharing the same fold but different sequence. The recent design of proteins displaying very high sequence identities but different 3D structure allows the unique opportunity to address the protein-folding problem from a complementary perspective. Here we explored by ℙ-value analysis the pathways of folding of three different heteromorphic pairs, displaying increasingly high-sequence identity (namely, 30%, 77%, and 88%), but different structures called G A (a 3-α helix fold) and G B (an α/β fold). The analysis, based on 132 site-directed mutants, is fully consistent with the idea that protein topology is committed very early along the pathway of folding. Furthermore, data reveals that when folding approaches a perfect two-state scenario, as in the case of the G A domains, the structural features of the transition state appear very robust to changes in sequence composition. On the other hand, when folding is more complex and multistate, as for the G Bs, there are alternative nuclei or accessible pathways that can be alternatively stabilized by altering the primary structure. The implications of our results in the light of previous work on the folding of different members belonging to the same protein family are discussed

Tunneling and delocalization in hydrogen bonded systems: a study in position and momentum space

Novel experimental and computational studies have uncovered the proton momentum distribution in hydrogen bonded systems. In this work, we utilize recently developed open path integral Car-Parrinello molecular dynamics methodology in order to study the momentum distribution in phases of high pressure ice. Some of these phases exhibit symmetric hydrogen bonds and quantum tunneling. We find that the symmetric hydrogen bonded phase possesses a narrowed momentum distribution as compared with a covalently bonded phase, in agreement with recent experimental findings. The signatures of tunneling that we observe are a narrowed distribution in the low-to-intermediate momentum region, with a tail that extends to match the result of the covalently bonded state. The transition to tunneling behavior shows similarity to features observed in recent experiments performed on confined water. We corroborate our ice simulations with a study of a particle in a model one-dimensional double well potential that mimics some of the effects observed in bulk simulations. The temperature dependence of the momentum distribution in the one-dimensional model allows for the differentiation between ground state and mixed state tunneling effects.Comment: 14 pages, 13 figure

a feature tracking model simulates the motion direction bias induced by phase congruency

Here we report a new motion illusion where the prevailing motion direction is strongly influenced by the relative phase of the harmonic components of the stimulus. The basic stimulus is the sum of three sinusoidal contrast-reversing gratings: the first, the third, and the fifth harmonic of two square wave gratings that drift in opposite direction. The phase of one of the fifth components was kept constant at 180 deg, whereas the phase of the other fifth harmonic was varied over the range 0Y150 deg. For each phase value of the fifth harmonic, the motion was strongly biased toward its direction, corresponding to the direction with stronger phase congruency between the three harmonics. The strength of the prevailing motion was assessed by measuring motion direction discrimination thresholds, by varying the contrast of the third and the fifth harmonics plaid pattern. Results show that the contrast of high harmonics had to be increased by more than a factor of 10, to achieve a balance of motion for phase differences greater than 60 deg between the 2 fifth harmonics. We also measured the dependence on the absolute phase of harmonic components and found that it is not an important parameter, excluding the possibility that local luminance cues could be mediating the effect. A feature-tracking model based on previous work is proposed to simulate the data. The model computes local energy function from a pair of space-time separable front stage filters and applies a battery of directional second stage mechanisms. It is able to simulate quantitatively the phase congruency dependence illusion and the insensitivity to overall phase. Other energy models based on directional filters fail to simulate the phase congruency dependency effect

Environmental Literacy of Ohio Adults

Author Institution: Food, Agricultural and Biological Engineering, The Ohio State University ; Strategic Research Group ; School of Health Sciences, Ohio UniversityEnvironmental literacy is defined as an understanding of natural systems combined with how they interact with human social systems. Past surveys have measured the pollution knowledge of adults. This study instead examined Ohio adult's knowledge of ecological principles as the basis of understanding. A telephone survey of 504 Ohio adults measured their knowledge of ecological principles. As a group, Ohio adults appear to understand four principles of ecology: biogeography, the earth as a biosphere, ecological energetics, and carrying capacity. Some additional attention should be paid to teaching Ohio adults about three principles of ecology: ecosystem succession, biotic interactions, and the importance of diversity. Most importantly, Ohio adults must learn more about the principle of materials cycling. Ohio adults showed poor understanding of the nitrogen, phosphorus, and hydrologic cycle and bioaccumulation

Profile of Ohio Adults with Low Environmental Literacy

Author Institution: Food, Agricultural and Biological Engineering, The Ohio State University ; Strategic Research Group ; School of Health Sciences, Ohio UniversityEnvironmental literacy is defined as an understanding of natural systems combined with how they interact with human social systems. An Ohio study measured adults' knowledge of ecological principles as the basis of understanding. A telephone survey of 504 Ohio adults measured their knowledge of ecological principles along with their demographics. Low literacy adults are significantly different from those who exhibit high literacy. The lowest literacy group was characterized as less educated, below the median household income, older, female, and minority. Low literacy adults are less likely to engage in outdoor activities, gain information from environmental groups, but are more likely to gain information from television. Low literacy adults are more likely than high literacy adults to use alternative transportation. In targeting environmental education programs to heads of households and Ohio voters, adults with low environmental literacy need to be approached differently than those with high literacy

Visual motion distorts visual and motor space

Much evidence suggests that visual motion can cause severe distortions in the perception of spatial position. In this study, we show that visual motion also distorts saccadic eye movements. Landing positions of saccades performed to objects presented in the vicinity of visual motion were biased in the direction of motion. The targeting errors for both saccades and perceptual reports were maximum during motion onset and were of very similar magnitude under the two conditions. These results suggest that visual motion affects a representation of spatial position, or spatial map, in a similar fashion for visuomotor action as for perception

Perception during double-step saccades

How the visual system achieves perceptual stability across saccadic eye movements is a long-standing question in neuroscience. It has been proposed that an efference copy informs vision about upcoming saccades, and this might lead to shifting spatial coordinates and suppressing image motion. Here we ask whether these two aspects of visual stability are interdependent or may be dissociated under special conditions. We study a memory-guided double-step saccade task, where two saccades are executed in quick succession. Previous studies have led to the hypothesis that in this paradigm the two saccades are planned in parallel, with a single efference copy signal generated at the start of the double-step sequence, i.e. before the first saccade. In line with this hypothesis, we find that visual stability is impaired during the second saccade, which is consistent with (accurate) efference copy information being unavailable during the second saccade. However, we find that saccadic suppression is normal during the second saccade. Thus, the second saccade of a double-step sequence instantiates a dissociation between visual stability and saccadic suppression: stability is impaired even though suppression is strong

Asymptomatic patients as a source of transmission of COVID-19 in homeless shelters

Objectives: Asymptomatic carriers account for over a third of all Coronavirus Disease 19 (COVID-19) cases and are characterized by the absence of symptoms but the same infectivity as symptomatic infections. The high percentage of asymptomatic COVID-19 patients is significant in settings with specific vulnerabilities, such as homeless shelters, where the consequences of an outbreak may be dramatic. In this work, we briefly report our experience on residents and staff of homeless shelters in the City of Rome, Italy, with a particular focus on asymptomatic transmission, and compare it with the available evidence. Methods: We performed routine Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) nasopharyngeal swab tests in all residents and staff of homeless shelters managed by the Eleemosynaria Apostolica of the Vatican City State in the city of Rome, Italy, in addition to daily symptom screening, body temperature monitoring, and application of other prevention measures. Results: We evaluated 298 persons and identified twelve positive cases (4%). Most of the positive cases (75%) were asymptomatic, while only three patients reported symptoms that included fever, diarrhea, and cough. Conclusions: Our data confirm the importance of early identification of asymptomatic carriers that could, in vulnerable conditions such as homeless shelters, spread the infection and cause outbreaks with severe consequences on individual and public health

Long-term effects of monocular deprivation revealed with binocular rivalry gratings modulated in luminance and in color

During development, within a specific temporal window called the critical period, the mammalian visual cortex is highly plastic and literally shaped by visual experience; to what extent this extraordinary plasticity is retained in the adult brain is still a debated issue. We tested the residual plastic potential of the adult visual cortex for both achromatic and chromatic vision by measuring binocular rivalry in adult humans following 150 minutes of monocular patching. Paradoxically, monocular deprivation resulted in lengthening of the mean phase duration of both luminance-modulated and equiluminant stimuli for the deprived eye and complementary shortening of nondeprived phase durations, suggesting an initial homeostatic compensation for the lack of information following monocular deprivation. When equiluminant gratings were tested, the effect was measurable for at least 180 minutes after reexposure to binocular vision, compared with 90 minutes for achromatic gratings. Our results suggest that chromatic vision shows a high degree of plasticity, retaining the effect for a duration (180 minutes) longer than that of the deprivation period (150 minutes) and twice as long as that found with achromatic gratings. The results are in line with evidence showing a higher vulnerability of the P pathway to the effects of visual deprivation during development and a slower development of chromatic vision in humans. Introductio