Data::Downloader

Downloading and organizing large amounts of files is challenging, and often done using ad hoc methods. This software is capable of downloading and organizing files as an OpenSearch client. It can subscribe to RSS (Really Simple Syndication) feeds and Atom feeds containing arbitrary metadata, and maintains a local content addressable data store. It uses existing standards for obtaining the files, and uses efficient techniques for storing the files. Novel features include symbolic links to maintain a sane directory structure, checksums for validating file integrity during transfer and storage, and flexible use of server-provided metadata

Can I teach that? Negotiating Taboo Language and Controversial Topics in the Language Arts Classroom

Book Revie

Sources and Cycling of Neodymium and Rare Earth Elements in the Arctic Amerasian Basin and Bering Sea

The isotopic composition of dissolved neodymium (143Nd/144Nd, expressed as εNd) behaves quasi-conservatively in the ocean and has been used as a palaeoceanographic tracer of ocean circulation. The εNd value of water masses is acquired—and often altered—during interaction with sediments along the margins; however, the processes involved in seawater εNd acquisition remains poorly characterized and quantified. Here we report the results of 349 Nd isotope and 354 rare earth element (REE) concentration measurements from 27 water column profiles across the Bering shelf and through the Arctic Amerasian Basin collected during U.S. Arctic GEOTRACES cruise HLY1502 (GEOTRACES section GN01). At the edge of the shelf (4 – 733 m), Bering Sea εNd is not appreciably altered from North Pacific endmember values despite transiting the Aleutian volcanic arc. The εNd values observed are then modified during transit across the eastern shelf; less radiogenic compositions accompany increases in the Nd concentration ([Nd]), particularly in samples below the pycnocline. The spatial pattern of [Nd] and less radiogenic εNd values point to benthic Nd additions to the water column, which is supported by a strong correlation between εNd values and 228Ra activities in sub-pycnocline samples and an enrichment of middle rare earth elements (MREE) The flux and the Nd isotope composition required to produce the observed changes was calculated by mass balance using a box model of the Bering Sea shelf. The results are consistent with Nd derived from the sedimentary authigenic ferromanganese component Near the Bering Strait, the εNd value is closer to the unaltered values at the southern Bering Shelf edge, reflecting the contribution of waters transiting the western shelf in a current system that moves faster and in deeper water compared to the eastern shelf, providing less opportunity for benthic driven alterations to the εNd value. Stations north of Bering Strait (on the Chukchi shelf) indicate the presence of Atlantic Arctic Water (AAW). The surface layer of the Arctic Amerasian Basin is a dynamic region effect by seasonal sea-ice formation and melt and the largest percentage of river flux relative to the basin size of any ocean basin. Moreover, a relatively fresh North Pacific flux from the Bering Sea combines with the other freshwater source to form a strong halocline, isolating the deep basin. The investigation demonstrates that sea-ice melt did not contribute to the Nd isotope and concentration budget. Arctic rivers, on the other hand, had a proportionate effect on the Nd isotopic composition and concentrations relative to their input, where Mackenzie River water shows a 15% contribution to the surface layer of the Canada Basin and a 20% Lena River contribution to the Makarov basin. Interestingly, the relationship between REE concentrations and the rivers deviates from the expected 71% loss due to estuarine scavenging, as seen in other non-Arctic River systems. This deviation may relate to the ratio of organic to inorganic nanoparticles and colloids in the rivers. The deep waters in the arctic ocean are largely derived from North Atlantic inflow through the Fram Strait and the Barents Sea. These waters overflow the Lomonosov Ridge at a depth of ~1700 m, filling the deep Amerasian basin at a rate of ~0.25 Sv. The slow transfer of water and the isolation of the deep Amerasian basin by the Lomonosov ridge and strong surface halocline contribute to the old ventilation age of ~450 yr for deep waters. Given the ‘quasi-conservative’ nature of Nd isotopes, the deep basin should reflect the less radiogenic εNd range of North Atlantic Water masses (εNd = -10.8 - -11.7). Moreover, samples collected from the Amerasian Basin in 2000 reflect these values with an εNd range of -10.7 to -11. However, this investigation found an εNd range of -8.8 to - 10.36. The increase εNd observed here can be attributed to dense brines forming on the East Siberian Shelf and Chukchi Shelf and some contributions from benthic sources. However, the exact cause for the isotopic shift is not clear

Neodymium Isotopic Signature of the Deep Western Boundary Current and the Distribution of Neodymium Isotopes and Concentrations Across Line W

The capacity of the neodymium (Nd) 143Nd/144Nd ratio to trace modern ocean circulation accurately allows for the assumption that the ratio can also accurately trace paleo ocean circulation. Therefore, a complete understanding of Nd cycling and its effect on the isotopic composition in the oceans is vital. Traditionally, Nd isotopic composition (Nd IC) is considered a conservative property in the open ocean, while coastal and margin environments tend to be dictated by nonconservative exchange processes. However, Nd concentrations ([Nd]) in the open ocean typically display a nutrient like profile, increasing with depth. Such a discrepancy between Nd IC and [Nd] has been referred to as the ‘Nd-Paradox’. In this study, Nd IC and [Nd] profiles are presented along the oceanographic section known as Line W, observing the interaction between the poleward flowing Gulf Stream (GS) and the equatorward Deep Western Boundary Current (DWBC) in accordance with the international GEOTRACES program. Surface Nd IC along the transect suggest mixing between three end members passing through the study area; fluvial (Nd IC ~ -11.03) from the margin, GS (Nd IC ~ 9.1) from the Gulf of Mexico and Caribbean, and subtropical mode water (STMW) (Nd IC ~ -9.5) in the open ocean. Just below the Surface mixed layer a prominent STMW signature, flows from the east through to the subsurface GS. Deeper along the margin, the extremely nonradiogenic Upper Labrador Seawater component to the DWBC remains relatively unchanged as it flows equatorward with a predominant -14.87 Nd IC. Classic Labrador Seawater also suggests a relatively unaltered Nd IC, reporting -13.5. However, two over flow water masses, Denmark Strait overflow water and Iceland Scotland overflow water do not conform to conservative mixing. Throughout the study area, [Nd] shows a surface maximum, consistent with lithogenic deposition. Between ~1000 and 2000 m, concentrations remain relatively consistent, coinciding with Nd IC, as a result of increased horizontal advection. Below 2000 m, [Nd] increase while Nd IC remains relatively consistent, indicative of reversible scavenging onto and off of sinking particles. Resuspended sediment in a benthic nepheloid layer produces an inverse relationship between Nd IC and [Nd], likely resulting from lithogenic material with a nonradiogenic Nd IC deposited to the seafloor

Evaluation of a tiller inhibition (tin) gene in wheat

Reduced tillering cereals have been proposed as being advantageous under terminal drought conditions through their presumed reduction in leaf area and increased partitioning of assimilate towards fertile stems. The reduced leaf area should reduce preanthesis transpiration and conserve soil water for grain filling while the partitioning of a greater proportion of biomass into fertile stems should subsequently result in more efficient partitioning of assimilate towards grain. The tiller inhibition (tin) gene reduces the number of tillers produced by spring wheat plants and this study was undertaken to assess the agronomic potential of this gene in addition to investigating the physiological changes associated with it on a plant and crop basis. The inhibition of tiller bud growth by the tin gene and the phenomenon known as "stunting" are linked and the latter appears to be an extreme manifestation of the former whereby the development of the mainstem apex is retarded. High light intensity, long photoperiod and low minimum temperatures are required to induce stunting, while high C02 induces associated traits such as reduced leaf length. The accumulation of biomass did not appear to be significantly affected by the presence of the tin gene. The reduction in tiller number was compensated for by more assimilate being partitioned into those tillers that were produced. The presence of the tin gene resulted in higher harvest index values, indicating more efficient partitioning of biomass into grain, as well as larger spikes with more kernels spike-1 at low densities. However, as spike densities of the tin lines approached 450 spike m-2, the differences in the characteristics associated with the tin gene disappeared. Leaf area index was not reduced by the presence of the tin gene as plants were able to produce longer and wider leaves. Using epidermal cells as an example, the increase in leaf length was due primarily to an increase in the number, rather than the length, of the leaf cells. The maximum rate of cellular division was also increased by the presence of the tin gene. Yield was not significantly altered by the presence of the tin gene under most conditions where it was tested. There were however significant changes in the composition of yield with kernel weight increased by 5 to 6% for the spring lines containing the tin gene relative to the near-isogenic pairs, and although the number of kernels spike-1 was often greater for the tin lines, kernels m-2 was reduced due to lower spike densities. The application of nitrogen increased spike densities in the tin lines, but not to similar densities as those produced by the freely tillering near-isogenic pairs. Water extraction was the same for the lines with and without the tin gene under field conditions, except at one site at maturity where the tin lines extracted more than their near-isogenic pairs. Root length density appeared to be unaffected by the tin gene. The intrinsic benefits of the tin gene appeared to be higher harvest index values, shorter stems and higher kernel weights as these traits were exhibited in the tin lines when plants were grown to achieve the same spike densities as their near-isogenic pairs. Most other traits such as increased number of spikelets spike-1, increased number of kernels spike-1 and increased stem length density appear to be contingent on spike densities being lower for the tin lines. Stem water soluble carbohydrates were also as high or higher for the tin lines under field conditions when spike densities were low, although when grown to achieve the same spike density the levels were the same or lower in the tin lines than their near-isogenic pairs

The Effect of Gun Shows on Gun-Related Deaths: Evidence from California and Texas

Thousands of gun shows take place in the U.S. each year. Gun control advocates argue that because sales at gun shows are much less regulated than other sales, such shows make it easier for potential criminals to obtain a gun. Similarly, one might be concerned that gun shows would exacerbate suicide rates by providing individuals considering suicide with a more lethal means of ending their lives. On the other hand, proponents argue that gun shows are innocuous since potential criminals can acquire guns quite easily through other black market sales or theft. In this paper, we use data from Gun and Knife Show Calendar combined with vital statistics data to examine the effect of gun shows. We find no evidence that gun shows lead to substantial increases in either gun homicides or suicides. In addition, tighter regulation of gun shows does not appear to reduce the number of firearms-related deaths.

A Model for Transforming Engineering Education Through Group Learning

Electrical engineering educators at Technological University Dublin (DIT) have successfully implemented pedagogical change. They now use group-based, student-centered and inquiry-driven approaches to teach emerging engineers. The objective of this was to foster students’ personal as well as professional skills (i.e., teamwork, communication, self-directed learning, etc.). This paper explores how such change was achieved and provides graphic models that draw from prior phenomenological studies and incorporates aspects of Rogers’ (1962) product adoption curve and Lowe’s (2012) interpretations of it

What Can Parents Do? A Review of State Laws Regarding Decision Making for Adolescent Drug Abuse and Mental Health Treatment

This study examined US state laws regarding parental and adolescent decision-making for substance use and mental health inpatient and outpatient treatment. State statues for requiring parental consent favored mental health over drug abuse treatment and inpatient over outpatient modalities. Parental consent was sufficient in 53%–61% of the states for inpatient treatment, but only for 39% – 46% of the states for outpatient treatment. State laws favored the rights of minors to access drug treatment without parental consent, and to do so at a younger age than for mental health treatment. Implications for how these laws may impact parents seeking help for their children are discussed

Normalizing Resource Identifiers using Lexicons in the Global Change Information System: Linking Earth Science Identifiers, Concepts, and Communities

Earth Science informatics involves collaboration between multiple groups of people with diverse specializations and goals,often using variations in terminology to refer to common resources. The uniformity of the resource identifiers often does not cross organizational boundaries. Because of this, permanent, widely used, unambiguous identifiers for resources are elusive. We examine real world cases of changing and inconsistent identifiers which inherently work against persistence and uniformity. We also present a solution which mediates factors in these situations; namely the creation of lexicons:mappings of sets of terms to URIs which are curated within the Global Change Information System (GCIS). We discuss aspects of the GCIS which facilitate the use of lexicons: an information model which disambiguates resources, a RESTful API which provides metadata through content-negotiation, and a strategy for long term curation of URIs, including mechanisms for handling changes to URIs and variations in terms used by different communities while providing persistent URIs and preserving relationships between resources We provide working definitions of terms,contexts, and lexicons, and relate them to the practical challenges of disambiguation and curation. We also discuss the mechanisms employed and architecture of the GCIS, and how these choices facilitate representation of persistent identifiers and mappings of them to identifiers used colloquially within various earth science communities of practice