2,071 research outputs found
Intensity measurements in the helium spectrum
The absolute and relative intensities of thirteen lines of the helium spectrum, extending through the visible region, have been measured by a modification of the method developed by Ornstein and Dorgelo. The change of the method has consisted in comparing each line directly with the known emission from a tungsten filament, operated under constant conditions. The results for a discharge in a capillary tube, with pressures from 1.92 to 34.3 mm show that the absolute intensities increase rapidly to a maximum for pressures in the neighborhood of 2 to 4 mm, below which they tend toward zero. The relative intensities of the singlet system are favored by lowered pressures, and the higher members of the triplet system are likewise favored over the lower members, while the relative intensities within the singlet series show little effect of pressure
Fabrication Of Steaks From Spent Hens
Research at SDSU has demonstrated that meat from spent laying hens (spent fowl) can be utilized in the production of fabricated steaks and/or roasts. Previous studies utilized raw meat from carcasses that were manually deboned. Under commercial deboning, meat that has been precooked is more easily separated from the bone. Precooking reduces the ability for meat to hold together or bind in a processed product. Precooked and raw spent fowl muscles were compared as raw material for the production of fabricated steaks. The objective of this research was to produce from precooked spent fowl muscle a palatable restructured product that will withstand handling, cooking and serving
Precision neutron interferometric measurement of the nd coherent neutron scattering length and consequences for models of three-nucleon forces
We have performed the first high precision measurement of the coherent
neutron scattering length of deuterium in a pure sample using neutron
interferometry. We find b_nd = (6.665 +/- 0.004) fm in agreement with the world
average of previous measurements using different techniques, b_nd = (6.6730 +/-
0.0045) fm. We compare the new world average for the nd coherent scattering
length b_nd = (6.669 +/- 0.003) fm to calculations of the doublet and quartet
scattering lengths from several modern nucleon-nucleon potential models with
three-nucleon force (3NF) additions and show that almost all theories are in
serious disagreement with experiment. This comparison is a more stringent test
of the models than past comparisons with the less precisely-determined nuclear
doublet scattering length of a_nd = (0.65 +/- 0.04) fm.Comment: 4 pages, 4 figure
COMPARISONS OF TWO SYMMETRIC DENSITY FUNCTION SOLUTIONS OF APHID POPULATION GROWTH MODELS
Aphids are among the world\u27s most devastating crop pests, and their population trajectories in field crops are characterized by rapid boom and bust, under the influence of bottom up (host plant) and top down (natural enemy) forces. Theoretical development in aphid growth trajectory modeling has recently advanced quite significantly, and the logistic and normal probability density functions have been found to provide analytical solutions to mechanistic models of the aphid population growth dynamics. The logistic or hyperbolic secant squared model captures a growth trajectory shaped by negative feedback of the aphid population on itself, due to the accumulation of adverse effect on its host plant and the coupling with natural enemies (bottom up as well as top down effect), while the normal model can be derived on the basis of a relationship between intrinsic growth rate and the host plant phenology. In this paper, we fit both models to a large number of observed aphid population trajectors and explore model properties. It is shown that, despite the diverging mechanistic underpinnings of the model, the generated growth curves, as fitted to the data, are very similar, as are characteristics, such as the height of the peak, the time of the peak and the accumulated area under the curve. Both models are useful workhorses for capturing aphid growth dynamics, but fitting one or either model cannot be used as evidence for the underpinning mechanisms, as different underpinning mechanisms result in similar population dynamics
Proinsulin-Reactive CD4 T Cells in the Islets of Type 1 Diabetes Organ Donors
Proinsulin is an abundant protein that is selectively expressed by pancreatic beta cells and has been a focus for development of antigen-specific immunotherapies for type 1 diabetes (T1D). In this study, we sought to comprehensively evaluate reactivity to preproinsulin by CD4 T cells originally isolated from pancreatic islets of organ donors having T1D. We analyzed 187 T cell receptor (TCR) clonotypes expressed by CD4 T cells obtained from six T1D donors and determined their response to 99 truncated preproinsulin peptide pools, in the presence of autologous B cells. We identified 14 TCR clonotypes from four out of the six donors that responded to preproinsulin peptides. Epitopes were found across all of proinsulin (insulin B-chain, C-peptide, and A-chain) including four hot spot regions containing peptides commonly targeted by TCR clonotypes derived from multiple T1D donors. Of importance, these hot spots overlap with peptide regions to which CD4 T cell responses have previously been detected in the peripheral blood of T1D patients. The 14 TCR clonotypes recognized proinsulin peptides presented by various HLA class II molecules, but there was a trend for dominant restriction with HLA-DQ, especially T1D risk alleles DQ8, DQ2, and DQ8-trans. The characteristics of the tri-molecular complex including proinsulin peptide, HLA-DQ molecule, and TCR derived from CD4 T cells in islets, provides an essential basis for developing antigen-specific biomarkers as well as immunotherapies
Associations between depressive symptoms and disease progression in older patients with chronic kidney disease:Results of the EQUAL study
Background: Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods: CKD patients (≥65 years; estimated glomerular filtration rate ≤20 mL/min/1.73 m2) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off ≤70; 0-100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results: Overall kidney function decline in 1326 patients was -0.12 mL/min/1.73 m2/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03-1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions: There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men.</p
Associations between depressive symptoms and disease progression in older patients with chronic kidney disease:Results of the EQUAL study
Background: Depressive symptoms are associated with adverse clinical outcomes in patients with end-stage kidney disease; however, few small studies have examined this association in patients with earlier phases of chronic kidney disease (CKD). We studied associations between baseline depressive symptoms and clinical outcomes in older patients with advanced CKD and examined whether these associations differed depending on sex. Methods: CKD patients (≥65 years; estimated glomerular filtration rate ≤20 mL/min/1.73 m2) were included from a European multicentre prospective cohort between 2012 and 2019. Depressive symptoms were measured by the five-item Mental Health Inventory (cut-off ≤70; 0-100 scale). Cox proportional hazard analysis was used to study associations between depressive symptoms and time to dialysis initiation, all-cause mortality and these outcomes combined. A joint model was used to study the association between depressive symptoms and kidney function over time. Analyses were adjusted for potential baseline confounders. Results: Overall kidney function decline in 1326 patients was -0.12 mL/min/1.73 m2/month. A total of 515 patients showed depressive symptoms. No significant association was found between depressive symptoms and kidney function over time (P = 0.08). Unlike women, men with depressive symptoms had an increased mortality rate compared with those without symptoms [adjusted hazard ratio 1.41 (95% confidence interval 1.03-1.93)]. Depressive symptoms were not significantly associated with a higher hazard of dialysis initiation, or with the combined outcome (i.e. dialysis initiation and all-cause mortality). Conclusions: There was no significant association between depressive symptoms at baseline and decline in kidney function over time in older patients with advanced CKD. Depressive symptoms at baseline were associated with a higher mortality rate in men.</p
Ising Universality in Three Dimensions: A Monte Carlo Study
We investigate three Ising models on the simple cubic lattice by means of
Monte Carlo methods and finite-size scaling. These models are the spin-1/2
Ising model with nearest-neighbor interactions, a spin-1/2 model with
nearest-neighbor and third-neighbor interactions, and a spin-1 model with
nearest-neighbor interactions. The results are in accurate agreement with the
hypothesis of universality. Analysis of the finite-size scaling behavior
reveals corrections beyond those caused by the leading irrelevant scaling
field. We find that the correction-to-scaling amplitudes are strongly dependent
on the introduction of further-neighbor interactions or a third spin state. In
a spin-1 Ising model, these corrections appear to be very small. This is very
helpful for the determination of the universal constants of the Ising model.
The renormalization exponents of the Ising model are determined as y_t = 1.587
(2), y_h = 2.4815 (15) and y_i = -0.82 (6). The universal ratio Q =
^2/ is equal to 0.6233 (4) for periodic systems with cubic symmetry.
The critical point of the nearest-neighbor spin-1/2 model is K_c=0.2216546
(10).Comment: 25 pages, uuencoded compressed PostScript file (to appear in Journal
of Physics A
Dielectric quantification of conductivity limitations due to nanofiller size in conductive powders and nanocomposites
Conducting submicron particles are well-suited as filler particles in
non-conducting polymer matrices to obtain a conducting composite with a low
percolation threshold. Going to nanometer-sized filler particles imposes a
restriction to the conductivity of the composite, due to the reduction of the
density of states involved in the hopping process between the particles,
compared to its value within the crystallites. We show how those microscopic
parameters that govern the charge-transport processes across many decades of
length scales, can accurately and consistently be determined by a range of
dielectric-spectroscopy techniques from a few Hz to infrared frequencies. The
method, which is suited for a variety of systems with restricted geometries, is
applied to densely packed 7-nm-sized tin-oxide crystalline particles with
various degree of antimony doping and the quantitative results unambiguously
show the role of the nanocrystal charging energy in limiting the hopping
process.Comment: 6 pages, 4 figure
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