Children's Librarians' Perceptions of Computers in the Children's Section of the Public Library

This research study examines children's librarians' perceptions of computers in the children's section of the public library. Combining a case study approach with personal interviews, it considers four North Carolina public children's librarians' impressions of the following: quality of computers and computer software; staff knowledge of and involvement with computers; procedures for computer use; patron use of computers; and children's librarians' attitudes and responses toward computers in the children's section of the public library. Based on their answers to interview questions, this study attempts to capture children's librarians' unique insights into the way computer services are implemented, utilized, and promoted. Finally, it offers a glimpse into current practices surrounding computers in the children's section of the public library, revealing both strengths and weaknesses, as well as illuminating tensions within the field of children's librarianship

Observation of vortex-nucleated magnetization reversal in individual ferromagnetic nanotubes

The reversal of a uniform axial magnetization in a ferromagnetic nanotube (FNT) has been predicted to nucleate and propagate through vortex domains forming at the ends. In dynamic cantilever magnetometry measurements of individual FNTs, we identify the entry of these vortices as a function of applied magnetic field and show that they mark the nucleation of magnetization reversal. We find that the entry field depends sensitively on the angle between the end surface of the FNT and the applied field. Micromagnetic simulations substantiate the experimental results and highlight the importance of the ends in determining the reversal process. The control over end vortex formation enabled by our findings is promising for the production of FNTs with tailored reversal properties.Comment: 20 pages, 13 figure

Dust in the Wind – Abdrift insektizidhaltiger Stäube – ein Risiko für Honigbienen (Apis mellifera L.)?

Dust in the wind - drift of dust containing insecticides - a risk for honey bees (Apis mellifera L.)?ZusammenfassungIm Zuge des Forschungsprogramms des Bundes und der Länder Bayern und Baden-Württemberg zur Bekämpfung des Westlichen Maiswurzelbohrers (Diabrotica virgifera virgifera LeConte) fanden 2009 und 2010 großangelegte Versuche zur Staubabdrift während der Aussaat von Clothianidin-haltigem Winterraps- und Maissaatgut statt. Dabei wurden die Kontamination von benachbarten blühenden Bienenweidepflanzen und die Auswirkungen der Drift auf Einzelbienen und Bienenvölker untersucht. Die Ergebnisse zeigen, dass vor allem die Feldrandstrukturen bei Staubabdrift mit für Bienen hochtoxischen Wirkstoffen ein hohes Gefährdungspotential bieten. Weitere Erkenntnisse über die Wirkung der Staubexposition auf Bienenvölker in Abhängigkeit der Applikationsmenge an Staub (0,5 g a.i./ha und 2,0 g a.i./ha Clothianidin; a.i.= active ingredient) konnten aus zwei Halbfreilandversuchen mit gezielter manueller Applikation von praxisorientierten Mengen an Maisbeizstaub-Erd-Gemisch in Phacelia gewonnen werden. Trotz relativ geringem Totenfall konnte nach Applikation von 2 g a.i./ha ein sichtbarer Effekt auf die Mortalität und Populationsentwicklung der Bienenvölker festgestellt werden, während die niedrige Konzentration gegenüber der Kontrollvariante keine Abweichungen aufwies. Stichwörter: Honigbiene (Apis mellifera L.), Bienenvergiftung, Clothianidin, Beizstaub, Abdrift AbstractIn the course of the German Diabrotica research program funded by the Federal Ministry of Food, Agriculture and Consumer protection and the states of Bavaria and Baden-Wuerttemberg large-scale drift trials were conducted during the sowing of winter oilseed rape and maize seeds treated with Clothianidin in 2009 and 2010. In the process the contamination of adjacent flowering bee forage plants and the impact of dust drift on individual bees and colonies were examined. The results show that primarily field edge structures are high risk areas for dust drift with highly toxic ingredients to bees. More data on the impact of exposure of dust on colonies depending on the application amount of dust (0.5 g a.i. / ha and 2.0 g a.i./ ha Clothianidin) were obtained from experimental approaches in tents with manual application of insecticide-loaded dust in Phacelia. Despite an overall low mortality, a visible effect on mortality of the colonies was detected for the higher concentration, whereas the low concentration compared with the untreated control showed no differences.Keywords: honeybee (Apis mellifera L.), bee poisoning, Clothianidin, abrasion dust, drif

Magnetization reversal of an individual exchange biased permalloy nanotube

We investigate the magnetization reversal mechanism in an individual permalloy (Py) nanotube (NT) using a hybrid magnetometer consisting of a nanometer-scale SQUID (nanoSQUID) and a cantilever torque sensor. The Py NT is affixed to the tip of a Si cantilever and positioned in order to optimally couple its stray flux into a Nb nanoSQUID. We are thus able to measure both the NT's volume magnetization by dynamic cantilever magnetometry and its stray flux using the nanoSQUID. We observe a training effect and temperature dependence in the magnetic hysteresis, suggesting an exchange bias. We find a low blocking temperature $T_B = 18 \pm 2$ K, indicating the presence of a thin antiferromagnetic native oxide, as confirmed by X-ray absorption spectroscopy on similar samples. Furthermore, we measure changes in the shape of the magnetic hysteresis as a function of temperature and increased training. These observations show that the presence of a thin exchange-coupled native oxide modifies the magnetization reversal process at low temperatures. Complementary information obtained via cantilever and nanoSQUID magnetometry allows us to conclude that, in the absence of exchange coupling, this reversal process is nucleated at the NT's ends and propagates along its length as predicted by theory.Comment: 8 pages, 4 figure

On the benefit of current and future ALPS data for improving Arctic coupled ocean-sea ice state estimation

Author Posting. © The Oceanography Society, 2017. This article is posted here by permission of The Oceanography Society for personal use, not for redistribution. The definitive version was published in Oceanography 30, no. 2 (2017): 69–73, doi:10.5670/oceanog.2017.223.Autonomous and Lagrangian platforms and sensors (ALPS) have revolutionized the way the subsurface ocean is observed. The synergy between ALPS-based observations and coupled ocean-sea ice state and parameter estimation as practiced in the Arctic Subpolar gyre sTate Estimate (ASTE) project is illustrated through several examples. In the western Arctic, Ice-Tethered Profilers have been providing important hydrographic constraints of the water column down to 800 m depth since 2004. ASTE takes advantage of these detailed constraints to infer vertical profiles of diapycnal mixing rates in the central Canada Basin. The state estimation framework is also used to explore the potential utility of Argo-type floats in regions with sparse data coverage, such as the eastern Arctic and the seasonal ice zones. Finally, the framework is applied to identify potential deployment sites that optimize the impact of float measurements on bulk oceanographic quantities of interest.This research was supported by NSF Grants PLR-1643339, PLR-1603903, and PLR- 1603660