Numerical Studies on the Magnetism of Fe-Ni-Mn Alloys in the Invar Region

By means of self-consistent semi-empirical LCAO calculations we study the itinerant magnetism of (Fe_{0.65}Ni_{0.35})_{1-y} Mn_y alloys for y between 0 and 0.22 at T=0 K, neglecting only the transverse spin components. We find that the magnetic behaviour is quite complicated on a local scale. In addition to ferromagnetic behaviour, also metastable spin-glass-like configurations are found. In the same approach, using a direct numerical calculation by the Kubo-Formalism without any fit parameters, we also calculate the electrical conductance in the magnetic state and find that the $y$-dependence observed in the experiments is well reproduced by our calculations, except of an overall factor of rougly 5, by which our resistivities are too large.Comment: 12 pages (Latex, to be applied 2 times) + 13 figures (eps-files

Ab-initio-calculations of the GMR-effect in Fe/V multilayers

In a self-consistent semi-empirical numerical approach based on ab-initio-calculations for small samples, we evaluate the GMR effect for disordered (001)-(3--Fe/3--V)$_\infty$ multilayers by means of a Kubo formalism. We consider four different types of disorder arrangements: In case (i) and (ii), the disorder consists in the random interchange of some Fe and V atoms, respectively, at interface layers; in case (iii) in the formation of small groups of three substitutional Fe atoms in a V interface layer and a similar V group in a Fe layer at a different interface; and for case (iv) in the substitution of some V atoms in the innermost V layers by Fe. For cases (i) and (ii), depending on the distribution of the impurities, the GMR effect is enhanced or reduced by increasing disorder, in case (iii) the GMR effect is highest, whereas finally, in case (iv), a negative GMR is obtained (''inverse GMR'').Comment: LaTex, 30 pages, including 16 drawings; to appear in JMM

Device-Compatible Chiroptical Surfaces through Self-Assembly of Enantiopure Allenes

Chiroptical methods have been proven to be superior compared to their achiral counterparts for the structural elucidation of many compounds. To expand the use of chiroptical systems to everyday applications, the development of functional materials exhibiting intense chiroptical responses is essential. Particularly, tailored and robust interfaces compatible with standard device operation conditions are required. Herein, we present the design and synthesis of chiral allenes and their use for the functionalization of gold surfaces. The self-assembly results in a monolayer-thin room-temperature-stable upstanding chiral architecture as ascertained by ellipsometry, X-ray photoelectron spectroscopy, and near-edge X-ray absorption fine structure. Moreover, these nanostructures anchored to device-compatible substrates feature intense chiroptical second harmonic generation. Both straightforward preparation of the device-compatible interfaces along with their chiroptical nature provide major prospects for everyday applications

Sustained Action of Developmental Ethanol Exposure on the Cortisol Response to Stress in Zebrafish Larvae and Adults

This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedThis study was supported by the National Centre for the replacement, refinement and reduction of animals in research

Water Quality Monitoring Protocol for Wadeable Streams and Rivers in the Northern Great Plains Network, Narrative Version 1.0

Executive Summary Preserving the national parks unimpaired for the enjoyment of future generations is a fundamental purpose of the National Park Service (NPS). To address growing concerns regarding the overall physical, chemical, and biological elements and processes of park ecosystems, the NPS implemented science-based management through “Vital Signs” monitoring in 270 national parks (NPS 2007). The Northern Great Plains Network (NGPN) is among the 32 National Park Service Networks participating in this monitoring effort. The NGPN will develop protocols over the next several years to determine the overall health or condition of resources within 13 parks located in Nebraska, North Dakota, South Dakota, and Wyoming. The NGPN identified water resources as a Vital Sign to monitor because water quality and quantity are important aspects of ecological processes that operate across multiple temporal and spatial scales. In the semi-arid region of the Northern Great Plains, surface-water resources within the NGPN are ecologically important. The 13 parks within the NGPN are diverse and vary greatly in size, visitation, and water resources. For example, the measured surface area of the Badlands National Park is about 243,000 acres, which represents nearly one-half of the combined acreage of all 13 NGPN park units; however, water resources within the park are scarce and the majority of streams are intermittent. The Badlands National Park annually hosts nearly 860,000 visitors. Mount Rushmore National Memorial also has limited water resources but hosts nearly 3 million visitors per year within its 1,278 acres. The Missouri National Recreational River contains the greatest portion of waterbodies within the NGPN, consisting of 139 rivers and streams within an areal extent of about 69,000 acres. Although water resources and acreage of the NGPN parks are varied, unifying factors among the parks include the relatively low population density within the Great Plains area and the strong emphasis on agrarian land use throughout the region. To address the diverse water quality concerns, NGPN received input from park staff and conducted pilot studies in 2009 and 2010. These factors, in combination with the NGPN budget allocations, resulted in development of the NGPN’s water quality monitoring protocol. This protocol will provide a context to aid park resource managers in their day-to-day decisions and allow the assessment of the status (current conditions) and trends (directional changes across time) of streams/rivers within selected NGPN parks. Data collected from integrating water resource monitoring, in combination with the inventory of additional Vital Signs, can be used to assess resources and to aid in sound managerial decisions by the NGPN parks. As recommended by Oakley et al. (2003), this protocol provides a narrative and the rationale for selection of streams and rivers within the NGPN that will be measured for water quality, including dissolved oxygen, pH, specific conductivity, and temperature. Standard operating procedures (SOPs) that detail the steps to collect, manage, and disseminate the NGPN water quality data are in an accompanying document. The sampling design documented in this protocol may be updated as monitoring information is collected and interpreted, and as refinement of methodologies develop through time. In addition, evaluation of data and refinement of the program may necessitate potential changes of program objectives. Changes to the NGPN water quality protocols and SOPs will be carefully documented in a revision history log