Product identification techniques used as training aids for analytical chemists

Laboratory staff assistants are trained to use data and observations of routine product analyses performed by experienced analytical chemists when analyzing compounds for potential toxic hazards. Commercial products are used as examples in teaching the analytical approach to unknowns

First gravitational lensing mass estimate of a damped Lyman-alpha galaxy at z=2.2

We present the first lensing total mass estimate of a galaxy, at redshift 2.207, that acts as a gravitational deflector and damped Lyman-alpha absorber on the background QSO SDSS J1135-0010, at redshift 2.888. The remarkably small projected distance, or impact parameter, between the lens and the source has been estimated to be 0.8 +/- 0.1 kpc in a recent work. By exploiting the Sloan Digital Sky Survey database, we establish a likely lensing magnification signal in the photometry of the QSO. This is determined to be 2.2 mag brighter (or 8 times more luminous) than the median QSO at comparable redshifts. We describe the total mass distribution of the lens galaxy with a one-component singular isothermal sphere model and contrast the values of the observed and model-predicted magnification factors. For the former, we use conservatively the photometric data of the 95% of the available distant QSO population. We estimate that the values of the lens effective velocity dispersion and two-dimensional total mass, projected within a cylinder with radius equal to the impact parameter, are included between 60 and 170 km/s and 2.1 x 10^9 and 1.8 x 10^10 M_Sun, respectively. We conclude by remarking that analyses of this kind are crucial to exploring the relation between the luminous and dark matter components of galaxies in the high-redshift Universe.Comment: 5 pages, 3 figures, accepted by MNRA

De-Trending Techniques: Methods for Cleaning Questionable Shock Data

Not all zero shifted acceleration data can De-trended using this technique. DC shifts, improper AC coupling, Circuit noise/EMI/EMR, Equivalent RC circuit gain response/Circuit saturation(Slew Rate Limited), fixture grounding and wiring losses can all contribute to bad shock data being recorded. Some data that is zero-shifted or exhibit large instantaneous velocity shifts is inherently bad and a retest is warranted. Clean Acceleration-Time history data can be bad upon examining the Velocity & Displacement profiles. Laser Vibrometers provide a high level of accuracy for pyrotechnic shock testing. Engineering judgment and experience will determine the validity of Shock data

An Investigation Of The Effects Of Using Digital Flash Cards To Increase Biology Vocabulary Knowledge In High School Students With Learning Disabilities

The field of science education, specifically biology, is becoming more challenging due to richer and more rigorous content demands. Along with new demands is the emergence of National Common Core Standards and End of Course Exams. Despite these changes, one factor remains consistent: As content knowledge increases, language demands also increase. For students with learning disabilities (LD), specifically those with language-based disabilities, the increasing vocabulary demand can lead to failure due not to a lack of understanding biology but the vocabulary associated with the content. In an attempt to impact high school students with learning disabilities‘ success in biology, a vocabulary intervention was investigated. Research suggests as more and more content is compressed into science courses, teachers are looking toward technology to assist with vocabulary mastery. The current research study examined the effects of a digital flash card intervention, Study Stack, versus a paper flash card intervention in biology for students with LD by measuring students‘ word knowledge and overall biology course achievement. Findings from repeated measures ANOVA showed a statistically significant increase on both the vocabulary assessment as well as the course grades in biology over time. However, the test of between effects considering card type yielded no differential change on vocabulary assessment and course grades in biology. Based on qualitative data, students interviewed liked the tool and found it to be helpful in learning biology terminology

Time delay of light signals in an energy-dependent spacetime metric

In this note we review the problem of time delay of photons propagating in a spacetime with a metric that explicitly depends on the energy of the particles (Gravity-Rainbow approach). We show that corrections due to this approach -- which is closely related to DSR proposal -- produce for small redshifts ($z<<1$) smaller time delays than in the generic Lorentz Invariance Violating case.Comment: 5 pages. This version contains two new references with respect to the published versio

Spin-to-Orbital Angular Momentum Conversion and Spin-Polarization Filtering in Electron Beams

We propose the design of a space-variant Wien filter for electron beams that induces a spin half-turn and converts the corresponding spin angular momentum variation into orbital angular momentum of the beam itself by exploiting a geometrical phase arising in the spin manipulation. When applied to a spatially coherent input spin-polarized electron beam, such a device can generate an electron vortex beam, carrying orbital angular momentum. When applied to an unpolarized input beam, the proposed device, in combination with a suitable diffraction element, can act as a very effective spin-polarization filter. The same approach can also be applied to neutron or atom beams.Comment: 9 pages, 5 figure

Approaching Space Time Through Velocity in Doubly Special Relativity

We discuss the definition of velocity as dE/dp, where E,p are the energy and momentum of a particle, in Doubly Special Relativity (DSR). If this definition matches dx/dt appropriate for the space-time sector, then space-time can in principle be built consistently with the existence of an invariant length scale. We show that, within different possible velocity definitions, a space-time compatible with momentum-space DSR principles can not be derived.Comment: 11 pages, no figures, minor changes, references added, final version to appear in PR

Highs and Lows in English Attachment

Grillo and Costa (2014) claim that Relative-Clause attachment ambiguity resolution is largely dependent on whether or not a Pseudo-Relative interpretation is available. Data from Italian, and other languages allowing Pseudo-Relatives, support this hypothesis. Pseudo-Relative availability, however, covaries with the semantics of the main predicate (e.g., perceptual vs. stative). Experiment 1 assesses whether this predicate distinction alone can account for prior attachment results by testing it with a language that disallows Pseudo-Relatives (i.e. English). Low Attachment was found independent of Predicate-Type. Predicate-Type did however have a minor modulatory role. Experiment 2 shows that English, traditionally classified as a Low Attachment language, can demonstrate High Attachment with sentences globally ambiguous between a Small-Clause and a reduced Relative-Clause interpretation. These results support a grammatical account of previous effects and provide novel evidence for the parser’s preference of a Small-Clause over a Restrictive interpretation, crosslinguistically

Nondestructive Measurement of Orbital Angular Momentum for an Electron Beam

Free electrons with a helical phase front, referred to as "twisted" electrons, possess an orbital angular momentum (OAM) and, hence, a quantized magnetic dipole moment along their propagation direction. This intrinsic magnetic moment can be used to probe material properties. Twisted electrons thus have numerous potential applications in materials science. Measuring this quantity often relies on a series of projective measurements that subsequently change the OAM carried by the electrons. In this Letter, we propose a nondestructive way of measuring an electron beam's OAM through the interaction of this associated magnetic dipole with a conductive loop. Such an interaction results in the generation of induced currents within the loop, which are found to be directly proportional to the electron's OAM value. Moreover, the electron experiences no OAM variations and only minimal energy losses upon the measurement, and, hence, the nondestructive nature of the proposed technique.Comment: 5 pages, 3 figures, and supplemental material that is comprised of text and 4 figure

Impacts of COVID-19 on the value chain of the hake small scale fishery in northern Peru

The supply chain mapping and analysis of secondary sources was supported by The Walton Family Foundation (Grant 2019-319) and the estimation of COVID-19 impacts by a 2019–20 SFC-ODA GCRF (University of St Andrews) Grant.All aspects of fish supply chains have been severely affected by the COVID-19 pandemic, with jobs, income and food security at risk. In Peru, small scale fisheries are fundamental for food security, contributing to about 2/3 of all fish consumed nationally. One of the most important resources which is more affordable for local and regional consumption is hake (Merluccius gayi peruanus). This study is a first attempt to describe the small-scale hake fishery value chain and to quantify the impact of COVID-19 from March to August 2020 in two fishing communities in northern Peru. The levels of fishing and primary buying were the most affected, and we estimate that ~ 23,000 fishing trips were not conducted, ~ 1680 t of hake was not landed (83% decrease), and 620 jobs were negatively impacted during this period. The gross income of vessel owners and primary buyers decreased by ~ $US 913,000. Marked differences were observed in the way each community responded to the pandemic and in their resilience to cope with COVID-19, despite being located less than 10 km away. In El Ñuro, which relied more heavily on the international market for hake trade, the value chain was affected for longer, while in Los Órganos which supplied national markets, the chain was restored after an initial period of adjustment. Our study suggests that government efforts should focus on facilitating a formalisation process in all levels of the chain, develop indicators to monitor the resumption of activities and the inclusion of a value chain approach to small-scale fisheries management.Publisher PDFPeer reviewe