612 research outputs found
Progress on the salmon investigation
An article detailing some of the conclusions of the salmon investigation undertaken by the author, on the River Eden and its tributaries, for the previous few years. It is proposed that seasonal changes in young salmon growth are related to water temperature variation. A figure is included showing length of fish compared to the average temperature of water in the River Eden over a two year duration. The article describes comparative work undertaken to date between three streams within the Thurso watershed and the River Eden. A table is included showing the average size of fish in each of the watercourses compared. Laboratory experiments on the effects of temperature on young salmon are outlined, as well as investigative work undertaken into the realtionship between fish scales and fish length
Structure, Transport and Magnetic properties in LaSrCoRuO
The perovskite solid solutions of the type
LaSrCoRuO with 0.25 x
0.75 have been investigated for their structural, magnetic and transport
properties. All the compounds crystallize in double perovskite structure. The
magnetization measurements indicate a complex magnetic ground state with strong
competition between ferromagnetic and antiferromagnetic interactions.
Resistivity of the compounds is in confirmation with hopping conduction
behaviour though differences are noted especially for = 0.4 and 0.6. Most
importantly, low field (50Oe) magnetization measurements display negative
magnetization during the zero field cooled cycle. X-ray photoelectron
spectroscopy measurements indicate presence of Co/Co and
Ru/Ru redox couples in all compositions except = 0.5.
Presence of magnetic ions like Ru and Co gives rise to additional
ferromagnetic (Ru-rich) and antiferromagnetic sublattices and also explains the
observed negative magnetization.Comment: Accepted for publication in J. Magn. Magn. Mate
X-ray photoelectron spectroscopic investigation of conducting polymer blends
Electrochemically prepared films of conducting polymers of polypyrrole and polythiophene and their blends with polyamide have been investigated by X-ray photoelectron spectroscopy. In the N1s region of the spectra of films containing polypyrrole the peak corresponding to N+ at 402.0 eV is separated from that of neutral N. The intensity of the N+ peak can be correlated with the electrical conductivity of the films and the spectroscopically derived ratio of F/N+ is close to 4 indicating that one BF4 - dopant ion is incorporated for every oxidized nitrogen center. In the spectra of films of polythiophene and its blends peaks corresponding to S and S+ can not be resolved but again the F/C ratio correlates with the electrical conductivity. © Springer-Verlag 1996
Electron spectroscopic investigation of Sn coatings on glasses
Float glasses of different thicknesses and a conducting tin oxide glass have been investigated using Photo and Auger Electron Spectroscopy induced by AlKα X-rays. On the basis of measured chemical XPS shifts in the binding energies the chemical state of Sn (+2 or +4) incorporated on the float glasses could not be assigned. The use of the Auger parameter allows to separate relaxation and chemical contributions. The derived true chemical shifts of Sn on float-glasses are larger than those of SnO and/or SnO2 due to the larger ionic environment of the glass matrix. Ar+ or HF etching reveals that the concentration of Sn decreases exponentially as a function of depth from the surface. © Springer-Verlag 1996
Low Temperature Neutron Diffraction Study of MnTe
Investigation of transport and magnetic properties of MnTe at low
temperatures sInvestigation of transport and magnetic properties of MnTe at low
temperatures showed anomalies like negative coefficient of resistance below
100K and a sharp rise in susceptibility at around 83K similar to a
ferromagnetic transition. Low temperature powder neutron diffraction
experiments were therefore carried out to understand the underlying phenomena
responsible for such anomalous behavior. Our study indicates that the rise in
susceptibility at low temperatures is due to strengthening of ferromagnetic
interaction within the plane over the inter plane antiferromagnetic
interactions.Comment: Appearing in J. Magn. Magn. Mate
Physical Activity as a Vital Sign: A Systematic Review
INTRODUCTION: Physical activity (PA) is strongly endorsed for managing chronic conditions, and a vital sign tool (indicator of general physical condition) could alert providers of inadequate PA to prompt counseling or referral. This systematic review examined the use, definitions, psychometric properties, and outcomes of brief PA instruments as vital sign measures, with attention primarily to studies focused on arthritis.METHODS: Electronic databases were searched for English-language literature from 1985 through 2016 using the terms PA, exercise, vital sign, exercise referral scheme, and exercise counseling. Of the 838 articles identified for title and abstract review, 9 articles qualified for full text review and data extraction.RESULTS: Five brief PA measures were identified: Exercise Vital Sign (EVS), Physical Activity Vital Sign (PAVS), Speedy Nutrition and Physical Activity Assessment (SNAP), General Practice Physical Activity Questionnaire (GPPAQ), and Stanford Brief Activity Survey (SBAS). Studies focusing on arthritis were not found. Over 1.5 years of using EVS in a large hospital system, improvements occurred in relative weight loss among overweight patients and reduction in glycosylated hemoglobin among diabetic patients. On PAVS, moderate physical activity of 5 or more days per week versus fewer than 5 days per week was associated with a lower body mass index (-2.90 kg/m2). Compared with accelerometer-defined physical activity, EVS was weakly correlated (r = 0.27), had low sensitivity (27%-59%), and high specificity (74%-89%); SNAP showed weak agreement (κ = 0.12); GPPAQ had moderate sensitivity (46%) and specificity (50%), and SBAS was weakly correlated (r = 0.10-0.28), had poor to moderate sensitivity (18%-67%), and had moderate specificity (58%-79%).CONCLUSION: Few studies have examined a brief physical activity tool as a vital sign measure. Initial investigations suggest the promise of these simple and quick assessment tools, and research is needed to test the effects of their use on chronic disease outcomes
Quantized spin waves in the metallic state of magnetoresistive manganites
High resolution spin waves measurements have been carried out in
ferromagnetic (F) La(1-x)(Sr,Ca)xMnO3 with x(Sr)=0.15, 0.175, 0.2, 0.3 and
x(Ca)=0.3. In all q-directions, close to the zone boundary, the spin wave
spectra consist of several energy levels, with the same values in the metallic
and the x\approx 1/8 ranges. Mainly the intensity varies, jumping from the
lower energy levels determined in the x\approx 1/8 range to the higher energy
ones observed in the metallic state. On the basis of a quantitative agreement
found for x(Sr)=0.15 in a model of ordered 2D clusters, the spin wave anomalies
of the metallic state can be interpreted in terms of quantized spin waves
within the same 2D clusters, embedded in a 3D matrix.Comment: 4 pages, 5 figure
Surface spectroscopic studies of Cs+, and Ba2+ sorption on chlorite-illite mixed clay
The sorption behavior of Cs+, and Ba2+ on natural clay was investigated using ToF-SIMS, XPS, and XRD. The natural clay was composed mainly of chlorite and illite in addition to quartz and calcite. Depth profiling up to 70 Å was performed at 10 Å steps utilizing ToF-SIMS to study the amount of sorbed Cs+ and Ba2+ as a function of depth in the clay matrix. The results suggest that Cs+ and Ba2+ ions were sorbed primarily by ion exchange coupled with hydrolytic sorption. According to ToF-SIMS and XPS results, the total sorbed amount of Ba2+ was larger than that of Cs+. Quantitative determination of the primary cations within the analyzed clay before and after sorption indicated that for Ba2+ sorption, Ca2+, Mg2+ and for Cs+ sorption Ca2+, K+ were the major exchanging ions. The XRD spectra of Ba-sorbed clay contained new peaks that were identified as BaCO3
Associations of Neighborhood Crime and Safety and with Changes in Body Mass Index and Waist Circumference
Using data from the Multi-Ethnic Study of Atherosclerosis (MESA), we evaluated associations of neighborhood crime and safety with changes in adiposity (body mass index (BMI) and waist circumference). MESA is a longitudinal study of cardiovascular disease among adults aged 45-84 years at baseline in 2000-2002, from 6 US sites, with follow-up for MESA participants until 2012. Data for this study were limited to Chicago, Illinois, participants in the MESA Neighborhood Ancillary Study, for whom police-recorded crime data were available, and who had complete baseline data (n = 673). We estimated associations of individual-level safety, aggregated neighborhood-level safety, and police-recorded crime with baseline levels and trajectories of BMI and waist circumference over time using linear mixed modeling with random effects. We also estimated how changes in these factors related to changes in BMI and waist circumference using econometric fixed-effects models. At baseline, greater individual-level safety was associated with more adiposity. Increasing individual- and neighborhood-level safety over time were associated with decreasing BMI over the 10-year period, with a more pronounced effect observed in women for individual-level safety and men for neighborhood-level safety. Police-recorded crime was not associated with adiposity. Neighborhood-level safety likely influences adiposity change and subsequent cardiovascular risk in multiethnic populations
Raman phonons as a probe of disorder, fluctuations and local structure in doped and undoped orthorhombic and rhombohedral manganites
We present a rationalization of the Raman spectra of orthorhombic and
rhombohedral, stoichiometric and doped, manganese perovskites. In particular we
study RMnO3 (R= La, Pr, Nd, Tb, Ho, Er, Y and Ca) and the different phases of
Ca or Sr doped RMnO3 compounds as well as cation deficient RMnO3. The spectra
of manganites can be understood as combinations of two kinds of spectra
corresponding to two structural configurations of MnO6 octahedra and
independently of the average structure obtained by diffraction techniques. The
main peaks of compounds with regular MnO6 octahedra, as CaMnO3, highly Ca doped
LaMnO3 or the metallic phases of Ca or Sr doped LaMnO3, are bending and tilt
MnO6 octahedra modes which correlate to R-O(1) bonds and Mn-O-Mn angles
respectively. In low and optimally doped manganites, the intensity and width of
the broad bands are related to the amplitude of the dynamic fluctuations
produced by polaron hopping in the paramagnetic insulating regime. The
activation energy, which is proportional to the polaron binding energy, is the
measure of this amplitude. This study permits to detect and confirm the
coexistence, in several compounds, of a paramagnetic matrix with lattice
polaron together with regions without dynamic or static octahedron distortions,
identical to the ferromagnetic metallic phase. We show that Raman spectroscopy
is an excellent tool to obtain information on the local structure of the
different micro or macro-phases present simultaneously in many manganites.Comment: Submitted to PR
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