MARKETS FOR NORTHERN PLAINS AQUACULTURE--CASE STUDY OF TILAPIA

The purpose of this study is to identify and investigate alternative fresh and frozen fillet markets for tilapia within the region. The competition for this market is primarily an imported product from Asia and Central America. Total imports plus domestic production has increased from 16.95 million pounds in 1992 to 70.74 million pounds in 1997. Thirty-seven of the 79 respondents handled tilapia in their business. Thirty of these businesses handled and preferred fresh fillets while ten handled frozen tilapia. The tilapia businesses were clear in their preferences: 5 to 7 ounce fillets, quick delivery response time, constant supply, taste and size, and suppliers oriented toward customer service. Twenty-six of the 37 respondents were open to new suppliers. The responding businesses which did not handle tilapia gave their reasons: lack of demand due to customer unfamiliarity, name recognition and taste of tilapia. The need for an established market, i.e., consumer demand, was the major factor. The domestically produced tilapia did not test well in any of the three sensory perception taste tests. The results of these tests indicate both a quality issue and a variation in quality from test to test. These issues need to be solved prior to initiating a marketing effort for fresh and frozen fillets.tilapia, North American Fish Farmers Cooperative, North Central Region, sensory evaluation, production, prices, size, imports, Marketing, Production Economics,

Does inhibitory repetitive transcranial magnetic stimulation augment functional task practice to improve arm recovery in chronic stroke?

Introduction. Restoration of upper extremity (UE) functional use remains a challenge for individuals following stroke. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive modality that modulates cortical excitability and is being explored as a means to potentially ameliorate these deficits. The purpose of this study was to evaluate, in the presence of chronic stroke, the effects of low-frequency rTMS to the contralesional hemisphere as an adjuvant to functional task practice (FTP), to improve UE functional ability. Methods. Twenty-two individuals with chronic stroke and subsequent moderate UE deficits were randomized to receive 16 sessions (4 times/week for 4 weeks) of either real-rTMS or sham-rTMS followed by 1-hour of paretic UE FTP. Results. No differences in UE outcomes were revealed between the real-rTMS and sham-rTMS intervention groups. After adjusting for baseline differences, no differences were revealed in contralesional cortical excitability postintervention. In a secondary analysis, data pooled across both groups revealed small, but statistically significant, improvements in UE behavioral measures. Conclusions. rTMS did not augment changes in UE motor ability in this population of individuals with chronic stroke. The chronicity of our participant cohort and their degree of UE motor impairment may have contributed to inability to produce marked effects using rTMS

Dietary combination of soy with a probiotic or prebiotic food significantly reduces total and LDL cholesterol in mildly hypercholesterolaemic subjects

Objective: We hypothesized that a dietary combination of soy with either a probiotic (yoghurt) or a prebiotic (resistant starch) would result in enhanced lipid-lowering effects compared with a control soy diet, possibly via improvements in isoflavone bioavailability. Subjects: Mildly hypercholesterolaemic subjects (men and post-menopausal women) older than 45 years were recruited via the local media. Thirty-six subjects commenced the study; five withdrew. Results: Soy+probiotic significantly decreased total cholesterol (4.72.0%; P=0.038) and soy+prebiotic significantly decreased total and low-density lipoprotein cholesterol (5.51.6%; P=0.003 and 7.32.2%; P=0.005, respectively). The bioavailabilities of daidzein, genistein or equol were not affected by probiotic or prebiotic consumption or associated with lipid changes. Conclusion: Dietary combination of soy with either a probiotic or a prebiotic resulted in significant lipid lowering, not related to isoflavone bioavailability

NASA Headquarters Space Operations Center: Providing Situational Awareness for Spaceflight Contingency Response

This paper discusses the NASA Headquarters mishap response process for the Space Shuttle and International Space Station programs, and how the process has evolved based on lessons learned from the Space Shuttle Challenger and Columbia accidents. It also describes the NASA Headquarters Space Operations Center (SOC) and its special role in facilitating senior management's overall situational awareness of critical spaceflight operations, before, during, and after a mishap, to ensure a timely and effective contingency response

Aerobrake assembly with minimum Space Station accommodation

The minimum Space Station Freedom accommodations required for initial assembly, repair, and refurbishment of the Lunar aerobrake were investigated. Baseline Space Station Freedom support services were assumed, as well as reasonable earth-to-orbit possibilities. A set of three aerobrake configurations representative of the major themes in aerobraking were developed. Structural assembly concepts, along with on-orbit assembly and refurbishment scenarios were created. The scenarios were exercised to identify required Space Station Freedom accommodations. Finally, important areas for follow-on study were also identified

Direct Dynamics Simulation of Dioxetane Formation and Decomposition Via the Singlet ·O–O–CH2–CH2· Biradical: Non-RRKM Dynamics

Electronic structure calculations and direct chemical dynamics simulations are used to study the formation and decomposition of dioxetane on its ground state singlet potential energy surface. The stationary points for 1O2 + C2H4, the singlet ·O–O–CH2–CH2· biradical, the transition state (TS) connecting this biradical with dioxetane, and the two transition states and gauche ·O–CH2–CH2–O· biradical connecting dioxetane with the formaldehyde product molecules are investigated at different levels of electronic structuretheory including UB3LYP, UMP2, MRMP2, and CASSCF and a range of basis sets. The UB3LYP/6-31G* method was found to give representative energies for the reactive system and was used as a model for the simulations. UB3LYP/6-31G* direct dynamics trajectories were initiated at the TS connecting the ·O–O–CH2–CH2· biradical and dioxetane by sampling the TS\u27s vibrational energy levels, and rotational and reaction coordinate energies, with Boltzmann distributions at 300, 1000, and 1500 K. This corresponds to the transition state theorymodel for trajectories that pass the TS. The trajectories were directed randomly towards both the biradical and dioxetane. A small fraction of the trajectories directed towards the biradical recrossed the TS and formed dioxetane. The remainder formed 1O2 + C2H4 and of these ∼ 40% went directly from the TS to 1O2 + C2H4without getting trapped and forming an intermediate in the ·O–O–CH2–CH2· biradical potential energy minimum, a non-statistical result. The dioxetane molecules which are formed dissociate to two formaldehyde molecules with a rate constant two orders of magnitude smaller than that predicted by Rice–Ramsperger–Kassel–Marcus theory. The reaction dynamics from dioxetane to the formaldehyde molecules do not follow the intrinsic reaction coordinate or involve trapping in the gauche ·O–CH2–CH2–O· biradical potential energy minimum. Important non-statistical dynamics are exhibited for this reactive system

Airborne Particles in Museums

Presents one in a series of research activities aimed at a better understanding of the origin and fate of air pollution within the built environment

Singlet and Triplet Potential Surfaces for the O 2 + C 2 H 4 Reaction

Electronic structure calculations at the CASSCF and UB3LYP levels of theory with the aug-cc-pVDZ basis set were used to characterize structures, vibrational frequencies, and energies for stationary points on the ground state triplet and singlet O2+C2H4potential energy surfaces (PESs). Spin-orbit couplings between the PESs were calculated using state averaged CASSCF wave functions. More accurate energies were obtained for the CASSCF structures with the MRMP2/aug-cc-pVDZ method. An important and necessary aspect of the calculations was the need to use different CASSCF active spaces for the different reaction paths on the investigated PESs. The CASSCF calculations focused on O2+C2H4 addition to form the C2H4O2biradical on the triplet and singlet surfaces, and isomerization reaction paths ensuing from this biradical. The triplet and singlet C2H4O2 biradicals are very similar in structure, primarily differing in their C−C−O−O dihedral angles. The MRMP2 values for the O2+C2H4→C2H4O2 barrier to form the biradical are 33.8 and 6.1 kcal/mol, respectively, for the triplet and singlet surfaces. On the singlet surface,C2H4O2 isomerizes to dioxetane and ethane-peroxide with MRMP2 barriers of 7.8 and 21.3 kcal/mol. A more exhaustive search of reaction paths was made for the singlet surface using the UB3LYP/aug-cc-pVDZ theory. The triplet and singlet surfaces cross between the structures for the O2+C2H4 addition transition states and the biradical intermediates. Trapping in the triplet biradical intermediate, following O32+C2H4 addition, is expected to enhance triplet→singlet intersystem crossing

Highly Enantioselective Zirconium-Catalyzed Cyclization of Aminoalkenes

Aminoalkenes are catalytically cyclized in the presence of cyclopentadienylbis(oxazolinyl)borato group 4 complexes {PhB(C5H4)(OxR)2}M(NMe2)2 (M = Ti, Zr, Hf; OxR = 4,4-dimethyl-2-oxazoline, 4S-isopropyl-5,5-dimethyl-2-oxazoline, 4S-tert-butyl-2-oxazoline) at room temperature and below, affording five-, six-, and seven-membered N-heterocyclic amines with enantiomeric excesses of \u3e90% in many cases and up to 99%. Mechanistic investigations of this highly selective system employed synthetic tests, kinetics, and stereochemistry. Secondary aminopentene cyclizations require a primary amine (1–2 equiv vs catalyst). Aminoalkenes are unchanged in the presence of a zirconium monoamido complex {PhB(C5H4)(Ox4S-iPr,Me2)2}Zr(NMe2)Cl or a cyclopentadienylmono(oxazolinyl)borato zirconium diamide {Ph2B(C5H4)(Ox4S-iPr,Me2)}Zr(NMe2)2. Plots of initial rate versus [substrate] show a rate dependence that evolves from first-order at low concentration to zero-order at high concentration, and this is consistent with a reversible substrate–catalyst interaction preceding an irreversible step. Primary kinetic isotope effects from substrate conversion measurements (k′obs(H)/k′obs(D) = 3.3 ± 0.3) and from initial rate analysis (k2(H)/k2(D) = 2.3 ± 0.4) indicate that a N–H bond is broken in the turnover-limiting and irreversible step of the catalytic cycle. Asymmetric hydroamination/cyclization of N-deutero-aminoalkenes provides products with higher optical purities than obtained with N-proteo-aminoalkenes. Transition state theory, applied to the rate constant k2 that characterizes the irreversible step, provides activation parameters consistent with a highly organized transition state (ΔS⧧ = −43(7) cal·mol–1 K–1) and a remarkably low enthalpic barrier (ΔH⧧ = 6.7(2) kcal·mol–1). A six-centered, concerted transition state for C–N and C–H bond formation and N–H bond cleavage involving two amidoalkene ligands is proposed as most consistent with the current data

Hydrographic data from Endeavor 214 : a study of the Gulf Stream - Deep Western Boundary Current crossover

In late June, 1990, a 17-day cruise aboard R/V ENDEAVOR was undertaken to investigate the manner in which the Deep Western Boundary Current (DWBC) crosses under the Gulf Stream. Forty-four CTD casts, comprising five sections, were made along with bottle measurements of Dissolved Oxygen, Nitrate, Nitrite, Phosphate, Silica, F-1l, and F-12. An acoustic transport float (POGO) was deployed at each station to obtain a measurement of the upper layer transport. The shipboard Acoustic Doppler Current Profiler (ADCP) measured currents thoughout the cruise. This report presents vertical profiles and sections of the bottle and CTD data a vector map of the average POGO currents, and listings of the bottle data.Funding was provided by the National Science Foundation and the Office of Naval Research under grant Number OCE90-09464