Distribution, morphology, and genetic affinities of dwarf embedded Fucus populations from the Northwest Atlantic Ocean

Dwarf embedded Fucus populations in the Northwest Atlantic Ocean are restricted to the upper intertidal zone in sandy salt marsh environments; they lack holdfasts and are from attached parental populations of F. spiralis or F. spiralis x F. vesiculosus hybrids after breakage and entanglement with halophytic marsh grasses. Dwarf forms are dichotomously branched, flat, and have a mean overall length and width of 20.3 and 1.3 mm, respectively. Thus, they are longer than Irish (mean 9.3 mm) and Alaskan (mean 15.0 mm) populations identified as F cottonii. Reciprocal transplants of different Fucus taxa in a Maine salt marsh confirm that F spiralis can become transformed into dwarf embedded thalli within the high intertidal zone, while the latter can grow into F. s. ecad lutarius within the mid intertidal zone. Thus, vertical transplantation can modify fucoid morphology and result in varying ecads. Microsatellite markers indicate that attached F spiralis and F vesiculosus are genetically distinct, while dwarf forms may arise via hybridization between the two taxa. The ratio of intermediate to species-specific-genotypes decreased with larger thalli. Also, F s. ecad lutarius consists of a mixture of intermediate and pure genotypes, while dwarf thalli show a greater frequency of hybrids

Education

Commencement address given by Dean Arthur Jay Klein, College of Education, to the Summer 1937 graduating class of The Ohio State University, Men's Gymnasium (Larkins Hall), Columbus, Ohio, September 3, 1937

A dial-reading translator for digital machine inputs

At the Southern California Co-operative Wind Tunnel, part of the need for rapid and accurate recording of instrument readings on tabular data sheets has been met by the development of a new automatic-translating device. This device has unusually low torque and is especially suitable for use with self-balancing potentiometers. The device picks up the reading as a whole number and electrically transfers it to standard printing and punched-card machines, without lag and without restricting the normal operation of the potentiometer

Interview with Arthur L. Klein

Interview in four sessions, February 1979 and April 1982, with Arthur L. ("Maj") Klein, who entered Throop College, the predecessor of the California Institute of Technology, in 1916. When R. A. Millikan arrived as the institute's head, Klein decided to change his major from mechanical engineering to physics in order to work with him, earning his bachelor's degree in 1921 and a PhD in 1925. He stayed on as a research fellow in physics and soon become involved in the activities of the new Guggenheim Aeronautical Laboratory at Caltech (GALCIT), along with Clark B. Millikan and the aircraft designer Arthur E. Raymond. He became an assistant professor of aeronautics in 1929. Klein designed much of GALCIT's 10-foot-diameter wind tunnel, which went into operation in 1929, and he later helped design the Southern California Cooperative Wind Tunnel (1945), which was financed by five Southern California aircraft companies and operated by Caltech. Klein was also responsible for many aspects of the design and testing of important aircraft, including Douglas Aircraft's DC series. He had begun consulting for Douglas Aircraft in 1932; by 1937, he was spending half his time there and half at Caltech, and this arrangement continued until his 1968 retirement from Caltech as a full professor in the Division of Engineering and Applied Science

S-STEM Becoming Engaged Engineering Scholars (BEES): Insights From Year 1

The Becoming Engaged Engineering Scholars (BEES) is an NSF S-STEM project that responds to the challenges in recruiting and retaining academically talented, low-income students from diverse backgrounds into undergraduate engineering programs. The new, ABET-accredited engineering programs at Western Washington University (WWU) have faced unique challenges in recruitment and retention, particularly in the first two years for pre-engineering students. Building on the success of prior S-STEM awards in other disciplines at WWU, the proposed program provides a systematic sequence of academic, social, and career support services specifically designed to enhance the success of engineering students during these first two years of undergraduate study. The primary program goal is to ensure the engineering programs offer an equitable pathway into engineering careers, particularly for low-income, academically talented students. In addition to providing financial support for participants, the BEES program adapts existing institutional support structures to offer a one-week bridge program prior to the start of their first year, implements a multi-level mentoring system that includes internal and external mentors, engages students in multiple curricular and co-curricular activities including an engaged engineering project experience, and offers a first-year seminar focused on engineering and society. The project devotes significant resources to studying the impact of the proposed activities. Specifically, the research seeks to answer how and to what extent the program activities support retention through the end of the 2nd year of engineering study, as well as how and to what extent the program activities impact students\u27 self-efficacy, identity, and sense of belonging. In this paper, the proposed program and its various support structures are described in detail, and some insights and results from the first year of the project are reviewed and discussed

The role of elasticity in simulating long-term tectonic extension

Author Posting. © Oxford University Press, 2016. This article is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 205 (2016): 728-743, doi:10.1093/gji/ggw044.While elasticity is a defining characteristic of the Earth's lithosphere, it is often ignored in numerical models of long-term tectonic processes in favour of a simpler viscoplastic description. Here we assess the consequences of this assumption on a well-studied geodynamic problem: the growth of normal faults at an extensional plate boundary. We conduct 2-D numerical simulations of extension in elastoplastic and viscoplastic layers using a finite difference, particle-in-cell numerical approach. Our models simulate a range of faulted layer thicknesses and extension rates, allowing us to quantify the role of elasticity on three key observables: fault-induced topography, fault rotation, and fault life span. In agreement with earlier studies, simulations carried out in elastoplastic layers produce rate-independent lithospheric flexure accompanied by rapid fault rotation and an inverse relationship between fault life span and faulted layer thickness. By contrast, models carried out with a viscoplastic lithosphere produce results that may qualitatively resemble the elastoplastic case, but depend strongly on the product of extension rate and layer viscosity U × ηL. When this product is high, fault growth initially generates little deformation of the footwall and hanging wall blocks, resulting in unrealistic, rigid block-offset in topography across the fault. This configuration progressively transitions into a regime where topographic decay associated with flexure is fully accommodated within the numerical domain. In addition, high U × ηL favours the sequential growth of multiple short-offset faults as opposed to a large-offset detachment. We interpret these results by comparing them to an analytical model for the fault-induced flexure of a thin viscous plate. The key to understanding the viscoplastic model results lies in the rate-dependence of the flexural wavelength of a viscous plate, and the strain rate dependence of the force increase associated with footwall and hanging wall bending. This behaviour produces unrealistic deformation patterns that can hinder the geological relevance of long-term rifting models that assume a viscoplastic rheology.This work was supported by NSF grants OCE-11-54238 (JAO, MDB), EAR-10-10432 (MDB) and OCE-11-55098 (GI), as well as a WHOI Deep Exploration Institute grant and start-up support from the University of Idaho (EM)

High growth rate 4H-SiC epitaxial growth using dichlorosilane in a hot-wall CVD reactor

Thick, high quality 4H-SiC epilayers have been grown in a vertical hot-wall chemical vapor deposition system at a high growth rate on (0001) 80 off-axis substrates. We discuss the use of dichlorosilane as the Si-precursor for 4H-SiC epitaxial growth as it provides the most direct decomposition route into SiCl2, which is the predominant growth species in chlorinated chemistries. A specular surface morphology was attained by limiting the hydrogen etch rate until the system was equilibrated at the desired growth temperature. The RMS roughness of the grown films ranged from 0.5-2.0 nm with very few morphological defects (carrots, triangular defects, etc.) being introduced, while enabling growth rates of 30-100 \mum/hr, 5-15 times higher than most conventional growths. Site-competition epitaxy was observed over a wide range of C/Si ratios, with doping concentrations < 1x1014 cm-3 being recorded. X-ray rocking curves indicated that the epilayers were of high crystallinity, with linewidths as narrow as 7.8 arcsec being observed, while microwave photoconductive decay (\muPCD) measurements indicated that these films had high injection (ambipolar) carrier lifetimes in the range of 2 \mus

Editorial: improving the nutritional content and quality of crops: promises, achievements, and future challenges

info:eu-repo/semantics/publishedVersio

Editorial: improving the nutritional content and quality of plants: promises, achievements, and future challenges, volume II

info:eu-repo/semantics/publishedVersio