Measuring Motivation Orientation and School Readiness in Children Served by Head Start

Currently, the most widely used direct assessment of motivation orientation for preschoolers has little to no research on its reliability and validity. This study examined the test–retest reliability and concurrent and predictive validity of this direct assessment. Results highlight potential limitations of this measure in capturing motivation orientation in preschoolers from low-income families

Optimal finite-time processes in stochastic thermodynamics

For a small system like a colloidal particle or a single biomolecule embedded in a heat bath, the optimal protocol of an external control parameter minimizes the mean work required to drive the system from one given equilibrium state to another in a finite time. In general, this optimal protocol obeys an integro-differential equation. Explicite solutions both for a moving laser trap and a time-dependent strength of such a trap show finite jumps of the optimal protocol to be typical both at the beginning and the end of the process.Comment: 4 pages, 1 figure, accepted for publication in Phys. Rev. Let

A one-dimensional model for theoretical analysis of single molecule experiments

In this paper we compare two polymer stretching experiments. The outcome of both experiments is a force-extension relation. We use a one-dimensional model to show that in general the two quantities are not equal. In certain limits, however, both force-extension relations coincide.Comment: 11 pages, 5 figure

Insights into the reproductive biology and fisheries of two commercially exploited species, shortfin mako (Isurus oxyrinchus) and blue shark (Prionace glauca), in the south-east Pacific Ocean

In 2005 and 2010,1241 Isurus oxyrinchus and 1153 Prionace glauca were collected from 178 longline sets in a ship-board observer programme in coastal waters off Caldera, Chile (27 degrees S). Catch composition was significantly biased towards I. oxyrinchus in 2005, but both species were caught in the same proportion in 2010. The sex ratio for L oxyrinchus and for P. glauca did not differ significantly from unity within or between years. Sharks matured (L-50) at a total length of 190.3 cm for male and 199.2 cm for female for P. glauca, and 180.2 cm for male I. oxyrinchus. Size-at-maturity for female I. oxyrinchus was not determined due to the near absence of mature specimens examined. Generalised additive models (GAMs) were used to examine catch per unit effort (CPUE) in relation to sea surface temperature, wind speed, time of day, hook depth and soak time. The GAMs revealed a significant effect of depth on P. glauca CPUE, and depth and wind speed for I. oxyrinchus CPUE. The predominance of small, immature sharks caught in the coastal, artisanal fishery indicates that both species may use the area as a pupping, and possibly a nursery zone during spring and summer. National data on catch composition and annual landings provide evidence of an increasing trend to land P. eauca, possibly to satisfy the international shark fin trade. Conservation measures, such as the introduction of a minimum capture size for sharks to protect the recruitment into the population, conservative fishing quotas and delimitation of fishing areas are necessary to ensure the sustainability of both species in the region. (C) 2013 Elsevier B.V. All rights reserved

Identification of new transitional disk candidates in Lupus with Herschel

New data from the Herschel Space Observatory are broadening our understanding of the physics and evolution of the outer regions of protoplanetary disks in star forming regions. In particular they prove to be useful to identify transitional disk candidates. The goals of this work are to complement the detections of disks and the identification of transitional disk candidates in the Lupus clouds with data from the Herschel Gould Belt Survey. We extracted photometry at 70, 100, 160, 250, 350 and 500 $\mu$m of all spectroscopically confirmed Class II members previously identified in the Lupus regions and analyzed their updated spectral energy distributions. We have detected 34 young disks in Lupus in at least one Herschel band, from an initial sample of 123 known members in the observed fields. Using the criteria defined in Ribas et al. (2013) we have identified five transitional disk candidates in the region. Three of them are new to the literature. Their PACS-70 $\mu$m fluxes are systematically higher than those of normal T Tauri stars in the same associations, as already found in T Cha and in the transitional disks in the Chamaeleon molecular cloud. Herschel efficiently complements mid-infrared surveys for identifying transitional disk candidates and confirms that these objects seem to have substantially different outer disks than the T Tauri stars in the same molecular clouds.Comment: Accepted for publication in A&A. 16 pages, 9 figures, 7 table

Plastic torsion on frictional joints and three-dimensional limit analysis of masonry structures

The plastic torsion of arbitrarily shaped, frictional joints is established together with its interactions with bending moments and shear forces. In order to solve limit analysis problems, a piecewise linear approximation of the yield function for rectangular joints is proposed. The proposal is incorporated into a model for limit analysis of masonry structures regarded as rigid block assemblages interacting through no tension, frictional joints. An example validates the proposal.Consejo Nacional de Ciencia y Tecnología of Mexico. Fundação para a Ciência e e Tecnologia (FCT) - Project SAPIENS 33935-99

Three-dimensional limit analysis of rigid blocks assemblages. Part II : load-path following solution procedure and validation

A novel solution procedure for the non-associated limit analysis of rigid blocks assemblages is proposed. This proposal produces better solutions than previously proposed procedures and it is also able to provide an insight into the structural behaviour prior to failure. The limit analysis model proposed in Part I of this paper and the solution procedure are validated through illustrative examples in three-dimensional masonry piers and walls. The use of limit analysis for three-dimensional problems incorporating non-associated flow rules and a coupled yield surface is novel in the literature

In-sewer field-evaluation of an optical fibre-based condition monitoring system

A Fiber Bragg Grating (FBG) based monitoring system for continuous humidity and temperature measurement has been designed and evaluated experimentally in a sewer environment with high corrosion rates, humidity and the presence of gaseous hydrogen sulfide. The monitoring system has been designed specifically for field use, including packaging prepared for the harsh environment and the challenges of the operation. The system is battery powered and has hardware for controlling the interrogation equipment, power management, data logging and 4G connectivity. Results obtained show the long-term performance, over a 6-month period of non-stop monitoring of real-time data using the same probe. The data acquired was compared to the environmental data of temperature and precipitation for this period from the same location, which showed a good correlation between the expected and the measured data values. The data obtained point to the success of the optical fibre-based sensor system for monitoring in these harsh environments over long periods

Condensation transition in DNA-polyaminoamide dendrimer fibers studied using optical tweezers

When mixed together, DNA and polyaminoamide (PAMAM) dendrimers form fibers that condense into a compact structure. We use optical tweezers to pull condensed fibers and investigate the decondensation transition by measuring force-extension curves (FECs). A characteristic plateau force (around 10 pN) and hysteresis between the pulling and relaxation cycles are observed for different dendrimer sizes, indicating the existence of a first-order transition between two phases (condensed and extended) of the fiber. The fact that we can reproduce the same FECs in the absence of additional dendrimers in the buffer medium indicates that dendrimers remain irreversibly bound to the DNA backbone. Upon salt variation FECs change noticeably confirming that electrostatic forces drive the condensation transition. Finally, we propose a simple model for the decondensing transition that qualitatively reproduces the FECs and which is confirmed by AFM images.Comment: Latex version, 4 pages+3 color figure

Searching for cavities of various densities in the Earth's crust with a low-energy electron-antineutrino beta-beam

We propose searching for deep underground cavities of different densities in the Earth's crust using a long-baseline electron-antineutrino disappearance experiment, realized through a low-energy beta-beam with highly-enhanced luminosity. We focus on four cases: cavities with densities close to that of water, iron-banded formations, heavier mineral deposits, and regions of abnormal charge accumulation that have been posited to appear prior to the occurrence of an intense earthquake. The sensitivity to identify cavities attains confidence levels higher than $3\sigma$ and $5\sigma$ for exposures times of 3 months and 1.5 years, respectively, and cavity densities below 1 g cm$^{-3}$ or above 5 g cm$^{-3}$, with widths greater than 200 km. We reconstruct the cavity density, width, and position, assuming one of them known while keeping the other two free. We obtain large allowed regions that improve as the cavity density differs more from the Earth's mean density. Furthermore, we demonstrate that knowledge of the cavity density is important to obtain O(10%) error on the width. Finally, we introduce an observable to quantify the presence of a cavity by changing the orientation of the electron-antineutrino beam, with which we are able to identify the presence of a cavity at the $2\sigma$ to $5\sigma$ C.L.Comment: 7 pages, 5 figures; matches published versio