1,857 research outputs found
Late Transition to Technical College: Perspectives from Males Approaching Adulthood
This study was about the transition experiences of a sample of nine young adult males who enrolled in technical college several years after leaving high school
1991 Needs Assessment of the Arab and Chaldean 60 and Over Population in the State of Michigan
This study is the result of a recognition of the sizeable representation of persons from Arabic-speaking nations who reside in the State of Michigan, most of them in the Detroit Metropolitan Area. The study replicates the Needs Assessment Survey of the Over 60 population which was conducted in 1985, and represents the third in a series of studies, each designed to focus on a specific ethnic subgroup of the Michigan population. Hispanic elders were studied in 1987, followed by Native American elders in 1989, and the present study of Arab and Chaldean elders in 1991
Spawning Aggregation Sites of Snapper and Grouper Species (Lutjanidae and Serranidae) on the Insular Shelf of Cuba
Twenty-one spawning aggregation sites on the Cuban shelf were identified for eight species of snappers (Lutjanus) and groupers (Epinephelus and Mycteroperca) using information from experienced fishers and field studies. Three sites are on the southeastern shelf, eight on the southwest shelf bordering the Golfo de Batabanó, two in the northwest, and eight in the north-central region along the margins of the Archipiélago de Sabana-Camagüey. These numbers may reflect sampling effort as much as absolute aggregation numbers, with most effort concentrated in the southwest and north-central regions. Additional studies, particularly field assessments, are needed to determine the current status and consistency of occurrence of many of these aggregations. Most sites occur near the shelf drop-off at depths of 20–50 m, over reef substrates. Some sites involve sequential use by multiple species over several seasons of the year. Fishing activities have impacted many of these aggregations, both during spawning events and during pre-spawning migrations. This information is being applied in the design of marine reserve networks for several Cuban archipelagos. Intraspecific variations in aggregation formation occur temporally among differing regions of Cuba. Such variations reinforce the need for expanded research efforts on spawning aggregations
Synthesis, X-ray Structures, Electronic Properties, and O\u3csub\u3e2\u3c/sub\u3e/NO Reactivities of Thiol Dioxygenase Active-Site Models
Mononuclear non-heme iron complexes that serve as structural and functional mimics of the thiol dioxygenases (TDOs), cysteine dioxygenase (CDO) and cysteamine dioxygenase (ADO), have been prepared and characterized with crystallographic, spectroscopic, kinetic, and computational methods. The high-spin Fe(II) complexes feature the facially coordinating tris(4,5-diphenyl-1-methylimidazol-2-yl)phosphine (Ph2TIP) ligand that replicates the three histidine (3His) triad of the TDO active sites. Further coordination with bidentate l-cysteine ethyl ester (CysOEt) or cysteamine (CysAm) anions yielded five-coordinate (5C) complexes that resemble the substrate-bound forms of CDO and ADO, respectively. Detailed electronic-structure descriptions of the [Fe(Ph2TIP)(LS,N)]BPh4 complexes, where LS,N = CysOEt (1) or CysAm (2), were generated through a combination of spectroscopic techniques [electronic absorption, magnetic circular dichroism (MCD)] and density functional theory (DFT). Complexes 1 and 2 decompose in the presence of O2 to yield the corresponding sulfinic acid (RSO2H) products, thereby emulating the reactivity of the TDO enzymes and related complexes. Rate constants and activation parameters for the dioxygenation reactions were measured and interpreted with the aid of DFT calculations for O2-bound intermediates. Treatment of the TDO models with nitric oxide (NO)—a well-established surrogate of O2—led to a mixture of high-spin and low-spin {FeNO}7 species at low temperature (−70 °C), as indicated by electron paramagnetic resonance (EPR) spectroscopy. At room temperature, these Fe/NO adducts convert to a common species with EPR and infrared (IR) features typical of cationic dinitrosyl iron complexes (DNICs). To complement these results, parallel spectroscopic, computational, and O2/NO reactivity studies were carried out using previously reported TDO models that feature an anionic hydrotris(3-phenyl-5-methyl-pyrazolyl)borate (Ph,MeTp–) ligand. Though the O2 reactivities of the Ph2TIP- and Ph,MeTp-based complexes are quite similar, the supporting ligand perturbs the energies of Fe 3d-based molecular orbitals and modulates Fe–S bond covalency, suggesting possible rationales for the presence of neutral 3His coordination in CDO and ADO
Steric Hindrance as a Mechanistic Probe for Olefin Reactivity: Variability of the Hydrogenic Canopy over the Isomeric Adamantylideneadamantane/Sesquihomoadamantene Pair (A Combined Experimental and Theoretical Study)
Access to each CC face of adamantylideneadamantane (AA) and sesquihomoadamantene (SA) is hindered by the hydrogenic canopy consisting of four β-hydrogens; otherwise, these olefins have quite normal environments. X-ray crystallography and density functional (DFT) calculations show a 0.5 Å larger annular opening in the protective cover of AA than that in SA. This contributes to the remarkable differences in reactivity toward various reagents, not only by limiting access to the olefin site in SA but also by inhibiting reactions which force these hydrogens closer together. Thus, AA is subject to typical olefin-addition reactions with bromine, sulfuryl chloride, m-chloroperbenzoic acid, dioxygen, and so forth, albeit sometimes at attenuated rates. On the other hand, SA is singularly unreactive under identical reaction conditions, except for the notable exceptions that include Brønsted (protonic) acids, a nitrosonium cation, and dichlorine. The exceptions are characterized as three sterically limited (electrophilic) reagents whose unique reactivity patterns are shown to be strongly influenced by steric access to the CC center. As such, the different degrees of steric encumbrance in the isomeric donors AA and SA shed considerable light on the diverse nature of olefinic reactions. In particular, they evoke mechanistic features in electrophilic addition versus electron transfer, which are otherwise not readily discernible with other less hindered olefinic donors. Transient structures of the olefinic-reaction intermediates such as the protonated carbocations AA−H+ and SA−H+ as well as the cation radicals AA•+ and SA•+ are probed by the combination of X-ray crystallographic analyses and density functional theoretical computations
Designing Sustainable Urban Futures : Concepts and Practices from Different Countries
Many 21st century cities have the potential to be sustainable and resource-saving living spaces when multifunctional structures, well-integrated transportation infrastructure, and democratic governance processes are present. Sustainable urban futures require a focus on the needs of humans and environmental best practices, as well as on the creative scope for community-driven sustainability innovations. This book is based on contributions from science and practice to the international symposium on “Sustainable Urban Development at Different Scales” organized by the Institute for Technology Assessment and Systems Analysis at the Karlsruhe Institute of Technology, Karlsruhe, Germany, in May 2014. The symposium used the global urbanization and reurbanization trend as an opportunity to examine cities as sustainable living spaces. This book identifi es concepts, analytic approaches, and practical applications for the design of sustainable urban futures among multiple disciplines and cultural backgrounds
Isolating the enhanced memory of a glassy system
Studies of glassy systems have shown how cyclic driving forms memories of
amplitude. We explore how choice of driving protocol reveals dramatically
different features of this memory. We model rearranging soft spots in sheared
amorphous solids as hysterons. Cyclic shear with positive and negative shear
strain reveals a return-point memory of multiple strains known from experiments
and molecular dynamics simulations, while asymmetric driving (e.g. only
positive shear strains) suppresses multiple memories. However, when we
introduce frustrated interactions between hysterons, we identify a different
mechanism that restores multiple memories for asymmetric driving and can be
used for design. Our work suggests that this enhanced memory is a signature of
frustration.Comment: 5 pages, 5 figure
Designing Sustainable Urban Futures : Concepts and Practices from Different Countries
This book is based on contributions from science and practice to the international symposium on “Sustainable Urban Development at Different Scales”. The symposium used the global urbanization and reurbanization trend as an opportunity to examine cities as sustainable living spaces. This book identifies concepts, analytic approaches, and practical applications for the design of sustainable urban futures among multiple disciplines and cultural backgrounds
Effect of Exercise on Reported Physical Sexual Satisfaction of University Students
The purpose of this study was to examine sexually active university students’ reported level of physical sexual satisfaction and perceived impact of exercise on physical satisfaction. In addition, this study investigated whether reported physical sexual satisfaction and perceived impact of exercise on physical sexual satisfaction differed based on current exercise status, body mass index, and gender. A sample of 678 college students completed a two page, 35-item survey instrument. Results indicated that students who were regular exercisers (engaged in vigorous physical activity for 20 minutes ? 3 days per week) were significantly more likely than students who were not regular exercisers to report higher levels of physical sexual satisfaction. Body mass index was also significantly correlated to physical sexual satisfaction. A series of multivariate analyses of variance revealed that physical sexual satisfaction and perceived impact of exercise on physical sexual satisfaction differed significantly based on gender. Overall, students perceived body image, sexual desirability perception, and physical strength as the three leading components of physical sexual satisfaction impacted by exercise. Since regular exercise may increase physical sexual satisfaction levels, health professionals could use the results of this study to help motivate individuals to enhance their physical sexual satisfaction by becoming more physically active
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