The ATPase cycle of PcrA helicase and its coupling to translocation on DNA.

The superfamily 1 bacterial helicase PcrA has a role in the replication of certain plasmids, acting with the initiator protein (RepD) that binds to and nicks the double-stranded origin of replication. PcrA also translocates single-stranded DNA with discrete steps of one base per ATP hydrolyzed. Individual rate constants have been determined for the DNA helicase PcrA ATPase cycle when bound to either single-stranded DNA or a double-stranded DNA junction that also has RepD bound. The fluorescent ATP analogue 2'(3')-O-(N-methylanthraniloyl)ATP was used throughout all experiments to provide a complete ATPase cycle for a single nucleotide species. Fluorescence intensity and anisotropy stopped-flow measurements were used to determine rate constants for binding and release. Quenched-flow measurements provided the kinetics of the hydrolytic cleavage step. The fluorescent phosphate sensor MDCC-PBP was used to measure phosphate release kinetics. The chemical cleavage step is the rate-limiting step in the cycle and is essentially irreversible and would result in the bound ATP complex being a major component at steady state. This cleavage step is greatly accelerated by bound DNA, producing the high activation of this protein compared to the protein alone. The data suggest the possibility that ADP is released in two steps, which would result in bound ADP also being a major intermediate, with bound ADP.P(i) being a very small component. It therefore seems likely that the major transition in structure occurs during the cleavage step, rather than P(i) release. ATP rebinding could then cause reversal of this structural transition. The kinetic mechanism of the PcrA ATPase cycle is very little changed by potential binding to RepD, supporting the idea that RepD increases the processivity of PcrA by increasing affinity to DNA rather than affecting the enzymatic properties per se

Robot Vision for Manipulation: A Trip to Real-World Applications

Along the last decades, Robotics research has taken a major turn from laboratories to factories and ordinary real-world environments. Consequently, new issues to be overcome have arisen, specially when autonomous, dexterous robots are in place. In this paper, we present this evolution in the case of robot vision for manipulation through several robot developments, by analysing their challenges and proposed solutions. This overview highlights the need of using different techniques depending on the task at hand and the scenario to work in.This work was supported in part by the Ministerio de Economía y Competitividad under Grant DPI2015-69041-R, in part by Universitat Jaume I under Grant UJI-B2018-74, and in part by Generalitat Valenciana under Grant PROMETEO/2020/034 and GV/2020/051

A proposal for a comprehensive grading of Parkinson's disease severity combining motor and non-motor assessments: meeting an unmet need.

Non-motor symptoms are present in Parkinson's disease (PD) and a key determinant of quality of life. The Non-motor Symptoms Scale (NMSS) is a validated scale that allows quantifying frequency and severity (burden) of NMS. We report a proposal for using NMSS scores to determine levels of NMS burden (NMSB) and to complete PD patient classification

Atmospheric image blur with finite outer scale or partial adaptive correction

Seeing-limited resolution in large telescopes working over wide wavelength range depends substantially on the turbulence outer scale and cannot be adequately described by one "seeing" value. We attempt to clarify frequent confusions on this matter. We study the effects of finite turbulence outer scale and partial adaptive corrections by means of analytical calculations and numerical simulations. If a von Karman turbulence model is adopted, a simple approximate formula captures the dependence of atmospheric long-exposure resolution on the outer scale over the entire practically interesting range of telescope diameters and wavelengths. In the infrared (IR), the difference with the standard Kolmogorov seeing formula can exceed a factor of two. We find that low-order adaptive turbulence correction produces residual wave-fronts with effectively small outer scale, so even very low compensation order leads to a substantial improvement in resolution over seeing, compared to the standard theory. Seeing-limited resolution of large telescopes, especially in the IR, is currently under-estimated by not accounting for the outer scale. On the other hand, adaptive-optics systems designed for diffraction-limited imaging in the IR can improve the resolution in the visible by as much as two times.Comment: A&A accepte

Effects Of Human Cadaveric Dissections In High School Biology

This study was conducted in a suburban public high school, which had a connection to the local university, to measure the achievement of dual enrollment senior students using traditional hands-on (THO) cadaveric dissections compared to non-traditional (NT) virtual dissections of the human body. The outcomes of this study may assist multicultural science educators and administrators, students and parents, to understand the importance of THO cadaveric dissections compared to NT virtual dissections tools in learning gross anatomy. Also, noted is the importance of public and higher education collaboration to help bridge the science resource gaps between educational settings

Contribution of changes in opal productivity and nutrient distribution in the coastal upwelling systems to Late Pliocene/Early Pleistocene climate cooling

The global Late Pliocene/Early Pleistocene cooling (~3.0–2.0 million years ago – Ma) concurred with extremely high diatom and biogenic opal production in most of the major coastal upwelling regions. This phenomenon was particularly pronounced in the Benguela upwelling system (BUS), off Namibia, where it is known as the Matuyama Diatom Maximum (MDM). Our study focuses on a new diatom silicon isotope (δ30Si) record covering the MDM in the BUS. Unexpectedly, the variations in δ30Si signal follow biogenic opal content, whereby the highest δ30Si values correspond to the highest biogenic opal content. We interpret the higher δ30Si values during the MDM as a result of a stronger degree of silicate utilisation in the surface waters caused by high productivity of mat-forming diatom species. This was most likely promoted by weak upwelling intensity dominating the BUS during the Late Pliocene/Early Pleistocene cooling combined with a large silicate supply derived from a strong Southern Ocean nutrient leakage responding to the expansion of Antarctic ice cover and the resulting stratification of the polar ocean 3.0–2.7 Ma ago. A similar scenario is hypothesized for other major coastal upwelling systems (e.g. off California) during this time interval, suggesting that the efficiency of the biological carbon pump was probably sufficiently enhanced in these regions during the MDM to have significantly increased the transport of atmospheric CO2 to the deep ocean. In addition, the coeval extension of the area of surface water stratification in both the Southern Ocean and the North Pacific, which decreased CO2 release to the atmosphere, led to further enhanced atmospheric CO2 drawn-down and thus contributed significantly to Late Pliocene/Early Pleistocene cooling

Summarizing Instruction in 11th-Grade U.S. History Course

The purpose of this study was to determine the effect of summarizing strategies on students’ academic achievement, attitude, and engagement toward learning. The study involved 59 high school 11th-Grade U.S. History students. One class received direct instruction, while the other received summarizing instruction. Achievement was measured using pre- and posttest scores. Achievement scores for summarizing instruction students were slightly higher than direct instruction students. Students’ attitudes toward U.S. History were measured using a nine-item survey, and results indicated that both groups believed summarizing strategies were sound strategies for learning and remembering new content knowledge. The student engagement results showed higher levels of engagement from the summarizing instruction group. Based on the findings, the implications of this study are important in supporting the use of summarizing instruction strategies to promote the improved attitudes and active engagement of students toward learning U.S. History

The UJI Aerial Librarian Robot: A Quadcopter for Visual Library Inventory and Book Localisation

Over time, the field of robotics has provided solutions to automate routine tasks in different scenarios. In particular, libraries are awakening great interest in automated tasks since they are semi-structured environments where machines coexist with humans and several repetitive operations could be automatically performed. In addition, multirotor aerial vehicles have become very popular in many applications over the past decade, however autonomous flight in confined spaces still presents a number of challenges and the use of small drones has not been reported as an automated inventory device within libraries. This paper presents the UJI aerial librarian robot that leverages computer vision techniques to autonomously self-localize and navigate in a library for automated inventory and book localization. A control strategy to navigate along the library bookcases is presented by using visual markers for self-localization during a visual inspection of bookshelves. An image-based book recognition technique is described that combines computer vision techniques to detect the tags on the book spines, followed by an optical character recognizer (OCR) to convert the book code on the tags into text. These data can be used for library inventory. Misplaced books can be automatically detected, and a particular book can be located within the library. Our quadrotor robot was tested in a real library with promising results. The problems encountered and limitation of the system are discussed, along with its relation to similar applications, such as automated inventory in warehouses.Support for the research conducted at UJI Robotic Intelligence Laboratory is provided in part by the Ministerio de Economía y Competitividad (DPI2015-69041-R), by Universitat Jaume I (UJI-B2018-74), and by Generalitat Valenciana (PROMETEO/2020/034, GV/2020/051)