Relative Production Rates Research Articles

Estimates of relative yields of strange baryons and antibaryons from pp and pA interactions

Relative production rates of hyperons and antihyperons from heavy ion collisions are expected to be sensitive signals of quark-gluon plasma formation. They have to be confronted to corresponding quantities from pp and pA collisions which are evaluated here.

Grain processing: effects on mixing, prehension, and other characteristics of feeds.

The primary objective of most grain processing of cattle diets is to increase starch availability. Evaluation of processing methods is usually based on ruminal or total tract starch disappearance and relative production rates (ADG, DMI, and gain: feed) demonstrated by cattle. Grain processing alters the mixing characteristics of grains and also influences steer preference for a grain and the manner in which grain is consumed. It is possible that mixing characteristics and selective eating influence production rates independent of starch availability when processed grains are fed. The magnitude of influence may depend upon the physical characteristics of other diet ingredients and feed intake. These relationships may work to improve or worsen production efficiencies. There is sufficient evidence to justify a closer evaluation of the influence of grain processing and feed ingredient combinations on mix quality, eating behavior, and true nutrient intakes of group-fed cattle.

Nitrogen fertility and leaf age effect on ethylene production of cotton in a controlled environment

The effect of nitrogen (N) fertility and its subsequent impact on ethylene production varies with plant species. Additionally, ethylene production reportedly increases or decreases with leaf age for several species. We examined leaf age and N fertility effects on ethylene production of cotton (Gossypium hirsutum L.) during the early vegetative stages of development (14 to 42 days after emergence) in a controlled environment. Ethylene production was determined by sampling leaf discs from the topmost fully expanded, middle, and bottom leaves of the canopy at 14, 21, 28, 35, and 42 days after emergence. Ethylene was collected from leaf discs in sealed test tubes and quantified by gas chromatography. Early in development, a N deficiency was associated with elevated levels of ethylene, suggesting stress ethylene production was occurring in response to a N-deficiency stress. As plant development progressed, however, increased ethylene production was associated with higher levels of applied N. Additionally, higher ethylene production was linearly associated with higher chlorophyll levels in all three leaves sampled. Ethylene production within plants receiving any given rate of N initially increased and then decreased with leaf age. The dynamics of this relationship suggest that as the N status of the plant changes during plant development, the relative rate of ethylene production, with regard to leaf age, is significantly influenced.

Quarkonia production at CDF

In the 1992–1995 runs CDF has collected large samples of J ψ , ψ(2 S) and ϒ identified through their muonic decay. In the charmonium system all production sources have been separately measured and compared with the theoretical predictions. A large excess of direct production has been observed for both ψ(2 S) and J ψ . The relative production rate for the χ c 1 and χ c 2 has also been measured. The unexpected results have lead to a profound revisitation of the theory of the production of Q Q bound states in high energy hadronic collisions.

Fatty acid specificity of immobilized kid goat pre-gastric esterase: Effects of pH

Kid goat pre-gastric esterase immobilized in a hollow fiber reactor was used to hydrolyse butteroil at buffer pH values of 5.0, 6.0 and 7.0. Overall hydrolysis proceeded fastest at pH 6.0, but changes in volatile fatty acid ratios with pH suggest that the same enzyme:substrate system can produce different flavor profiles, e. g., at pH 6.0 the relative rate of production of undesirable soaplike flavors is minimized.

A mass balance of 13C and 12C in an organic-rich methane-producing marine sediment

The sedimentary budgets of 12C and 13C were determined for the well-characterized coastal site of Cape Lookout Bight, North Carolina, USA. Degradation of organic carbon with a δ 13C value of −19.2 ± 0.2‰ proceeds via sulfate reduction and methanogenesis. Neither process detectably alters the 13C/ 12C composition of the solid phase organic fraction that is ultimately buried. The remineralized carbon (ΣCO 2 plus CH 4) has an annual mean δ 13C of −18.7 ± 2.2‰, indicating that the breakdown of solid phase organic material to dissolved intermediates does not discriminate between 13C and 12C. The dominant carbon isotope effect expressed during the diagenesis of the organic matter is associated with methanogenesis. Methane produced at this site has a measured annual mean δ 13C value of −58.9 ± 1.4‰. The ΣCO 2 is enriched in 13C (−11.0 ± 1.2‰) because of the preferential synthesis of 12CH 4. The relative rate of production of the ΣCO 2 and CH 4, which is controlled by the depositional flux of metabolizable organic carbon, along with the fractionation factor associated with methanogenesis and the isotopic composition of the source carbon, determine the 13C/ 12C content of the two diagenetic endproducts.

A study of charm hadron production in ${\rm Z} \rightarrow c\bar{c}$ and ${\rm Z} \rightarrow b\bar{b}$ decays at LEP

Measurements of the production of the weakly decaying charmed hadrons: D0, D+, D + andΛ + in both $$Z^0 \to c\bar c$$ and $$Z^0 \to b\bar b$$ events are reported. By summing the partial contributions from each of these states we measure the partial width for Z0 decays into a $$c\bar c$$ pair as: $$\frac{{\Gamma _{c\bar c} }}{{\Gamma _{had} }} = 0.167 \pm 0.011(stat) \pm 0.011(sys) \pm 0.005(br)$$ where the errors are statistical, systematic and due to the uncertainties in the charmed hadron branching ratios, respectively. The relative production rates for the formation of the charmed hadrons from primaryc quarks is found to be in good agreement with continuum e + e − data at √s≈10 GeV. The measured rates of these four charmed hadrons inb hadron decays is found to account for $$1.061 \pm 0.045(stat) \pm 0.060(sys) \pm 0.037(br)$$ c or $$\bar c$$ quarks perb hadron decay. Comparison of the relative rates of the different charmed hadron species withϒ(4S) data indicates higher rates for D Emphasis>+ andΛ + hadrons and lower rates of D0 and D+ mesons as expected due to the different mixture ofb hadrons.

Approximate scaling in particle production rates in e+e− annihilations and predictions for LEP 2

It is shown that relative production rates, 〈n (part)〉 〈n ch 〉 , of the pseudoscalar and vector mesons, and octet and decuplet baryons in e + e − annihilations are determined only by particleisospins, spins and their masses and approximately energy independent in the PETRA/PEP-LEP 1 energy range. From this and extrapolating the energy dependence of the average charged particle multiplicity, 〈 n ch〉, the empirical estimates for the meson and baryon production rates in e + e − annihilations at LEP 2 energies are obtained.

Radio line observations of comet 109P/Swift-Tuttle at IRAM

Observations are presented of comet 109P/Swift-Tuttle (1992t and 1992 XXVIII in the old style designations) obtained at the IRAM 30 m millimetre radio telescope both before (Nov. 1992) and after perihelion (Jan. 1993), when r h was ∼ 1 AU and Δ between 1 and 2 AU. The molecules HCN, H 2S, H 2CO and CH 2OH were detected, with good signal-to-noise ratios (up to 30). The line profiles are strongly asymmetric with a cusp at negative velocities; this leads to an important shift (−0.45 km s −1) of the mean gas velocity with respect to the nucleus. This profile is most probably linked to the jets seen at visual wavelengths. From methanol rotation diagrams, average rotational temperatures of 70 K for November 21 and 45 K for January are estimated. An isotropic distribution of the molecules is assumed, and Q(H 2O) ∼ 4.0 and 3.5 × 10 29 molec. s −1 for November 21 and January, respectively. Relative production rates Q Q (H 2O) of 0.1, 0.4, 0.5 and 4–7% on November 21, 1992 for HCN, H 2S, H 2CO and CH 3OH, respectively, and 0.05, 0.2 and 2% on January 6–7, 1993, for HCN, H 2CO and CH 3OH, respectively, are derived. The effect of coma anisotropy on the derivation of these rates is briefly discussed. The decrease of non-water parent molecules from November to January, to be confirmed, raises questions about the nucleus homogeneity or sublimation process.

Study of Kin s0, Λ and [formula omitted] production in S-W collisions at 200 GeV/ c per nucleon

Results on K s 0 production at central rapidity in sulphur-tungsten interactions are presented. The selection procedure used to identify K s 0 particles through their decay to two charged pions is described. The m T spectra for K s 0, Λ and Λ and the relative production rates K s 0 Λ and K s 0 Λ , calculated in the kinematic region p T > 1 GeV/ c and 2.5 ≤ y LAB ≤ 3.0, are discussed.

A study of charm hadron production in $$Z^0 \to c\bar c$$ and $$Z^0 \to b\bar b$$ decays at LEPdecays at LEP

Measurements of the production of the weakly decaying charmed hadrons: D0, D+, Ds+ andΛc+ in both\(Z^0 \to c\bar c\) and\(Z^0 \to b\bar b\) events are reported. By summing the partial contributions from each of these states we measure the partial width for Z0 decays into a\(c\bar c\) pair as: $$\frac{{\Gamma _{c\bar c} }}{{\Gamma _{had} }} = 0.167 \pm 0.011(stat) \pm 0.011(sys) \pm 0.005(br)$$ where the errors are statistical, systematic and due to the uncertainties in the charmed hadron branching ratios, respectively. The relative production rates for the formation of the charmed hadrons from primaryc quarks is found to be in good agreement with continuum e+e− data at √s≈10 GeV.

Nitric oxide regulation of tissue free radical injury.

We have presented evidence from a broad range of chemical, cell biological, and in vivo studies showing that .NO can mediate tissue-protective reactions during oxidant stress, as well as toxic and tissue prooxidant effects. One predominant factor that has been identified which influences .NO being protective versus toxic is the relative rates of production and concentrations of .NO and the more "traditional" family of reactive oxygen species, including O2.-, H2O2, .OH, LO., LOO., and high valency complexes of iron. Also, since so many anti-neutrophil actions of .NO have been described, it is likely that .NO will serve a protective role in acute inflammatory reactions. One issue is certain--many new truths remain to be revealed, as we continue to develop our understanding of the toxicology of reactive oxygen- and nitrogen-containing species.

N2+ (X), N2+ (A), and N2+ (B) Production in e− + N2 collisions

A variety of cross‐section data for electron‐impact ionization of N2 have been analyzed, including those for total N2+ production and for the Meinel and first‐negative emissions from excited N2+ ions. These results are used to infer the relative production rates of the N2+ (X), N2+ (A), and N2+ (B) product ions during the reactions, yielding branching‐ratio fractions of 0.320±0.147, 0.535±0.112, and 0.145±0.019, respectively, for 100‐eV electrons. The data are compared with the relative formation rates of these ions recently obtained using electron‐energy spectroscopy coincidence measurements. The significant discrepancy between these two procedures is discussed, and the results obtained from our data analysis are recommended for auroral modeling at the present time.

Inclusive production of neutral vector mesons in hadronic Z decays

Data on the inclusive production of the neutral vector mesonsρ 0(770),ω(782), K*0(892), andφ(1020) in hadronic Z decays recorded with the ALEPH detector at LEP are presented and compared to Monte Carlo model predictions. Bose-Einstein effects are found to be important in extracting a reliable value for theρ 0 production rate. An averageρ 0 multiplicity of 1.45±0.21 per event is obtained. Theω is detected via its three pion decay modeω→π + π − π 0 and has a total rate of 1.07±0.14 per event. The multiplicity of the K*0 is 0.83±0.09, whilst that of theφ is 0.122±0.009, both measured using their charged decay modes. The measurements provide information on the relative production rates of vector and pseudoscalar mesons, as well as on the relative probabilities for the production of hadrons containing u, d, and s quarks.

Measurements of alkyl and multifunctional organic nitrates at a rural site in Ontario

Measurements of alkyl and multifunctional organic nitrates were conducted at a rural site in Ontario during periods with varying levels of photochemical activity. On August 6 and August 21–23, 1992, a total of 17 organic nitrates (12 C3‐C6 alkyl nitrates, 4 C2‐C4 hydroxynitrates and 1,2‐dinitrooxybutane) were quantitatively determined in atmospheric samples. The sum of the organic nitrate concentrations was found to be correlated with ozone and ranged from 12 to 140 parts per trillion (volume). The total concentration of organic nitrates measured contributed from 0.5 to 3.0% to the total odd nitrogen species. On average, the alkyl nitrates represented 82%, the hydroxynitrates 16%, and the dinitrate 2% of the total measured organic nitrates. Unidentified organic nitrate peaks determined from an organic nitrate selective detector were found to contribute an additional 0.25% to the total odd nitrogen budget. The distribution of alkyl and hydroxy nitrates measured was found to be reasonably consistent with computed relative production rates, for photochemically active air masses. Although the inclusion of the multifunctional organic nitrates does not significantly change the measured contribution of these species to NOy, it is shown that the isoprene nitrates may contribute as much as the combined contribution of all the measured organic nitrates.

Mathematical analysis of the relationship between blood flow and uptake of nutrients in the mammary glands of a lactating cow

A dynamic mathematical model of blood flow regulation in the mammary glands of a lactating cow was constructed from a principle of local vasodilator release in response to changes in intracellular adenylate charge. An equation was derived to predict uptake of the milk precursors acetate, glucose, amino acids and fatty acids, as affected by mammary blood flow rate. Metabolism of the precursors to milk components and CO2 was simulated with a set of empirically derived equations. Relative rates of ATP production and utilization regulated both the number of perfused capillaries and the conductance of arteriolar segments in the mammary glands. The model simulated local control phenomena of functional and reactive hyperaemia, and simulation of autoregulation under changing arterial pressure suggested a predominance of precapillary sphincter regulation. It was predicted that an increase in blood flow without the mammary capacity to utilize blood metabolites efficiently would be detrimental to milk synthesis. Conversely, increased blood flow through changes in mammary activity resulted in predictions of higher milk production. It was proposed that the equation for uptake, [equation: see text] be used in analysis of mammary arteriovenous differences.

Hadroproduction and polarization of charmonium.

In the limit of heavy-quark mass, the production cross section and polarization of quarkonia can be calculated in perturbative QCD. We study the ${\mathit{p}}_{\mathrm{\ensuremath{\perp}}}$-averaged production of charmonium states in \ensuremath{\pi}N collisions at fixed target energies. The data on the relative production rates of J/\ensuremath{\psi} and ${\mathrm{\ensuremath{\chi}}}_{\mathit{J}}$ are found to disagree with leading twist QCD. The polarization of the J/\ensuremath{\psi} indicates that the discrepancy is not due to poorly known parton distributions nor to the size of higher order effects (K factors). Rather, the disagreement suggests important higher twist corrections, as has been surmised earlier from the nuclear target A dependence of the production cross section.

Evidence for Enhanced Mineral Dissolution in Organic Acid‐Rich Shallow Ground Water

AbstractTotal concentrations of formate, acetate, and isobutyrate varied from less than 5 to greater than 9,000 μmol/l over distances of < 3 m in ground water from a shallow hydrocarbon contaminated aquifer. Laboratory incubations of aquifer material indicate that organic acid concentrations were dependent on the amount of hydrocarbon loading in the sediment and the relative rates of microbial organic acid production and consumption. In heavily contaminated sediments, production greatly exceeded consumption and organic acid concentrations increased. In lightly contaminated sediments rates were essentially equal and organic acid concentrations remained low. Concentrations of dissolved calcium, magnesium, and iron generally were one to two orders of magnitude higher in organic acid‐rich ground water than in ground water having low organic acid concentrations. Carbonate and Fe(III)‐oxyhydroxide minerals were the likely sources of these elements. Similarly, concentrations of dissolved silica, derived from quartz and k‐feldspar, were higher in organic acid‐rich ground water than in other waters. The positive relation (r = 0.60, p < .05, n = 16) between concentrations of silica and organic acids suggests that the microbially mediated buildup of organic acids in ground water enhanced quartz/k‐feldspar dissolution in the aquifer, although it was not the only factor influencing their dissolution. A model that included organic acid microequivalents normalized by cation microequivalents significantly strengthened the correlation (r = 0.79, p < .001, n = 16) between dissolved silica and organic acid concentrations, indicating that competition between silica and cations for complexation sites on organic acids also influenced quartz/k‐feldspar dissolution. Physical evidence for enhanced mineral dissolution in organic acid‐rich waters included scanning electron microscopy images of highly corroded quartz and k‐feldspar grains from portions of the aquifer containing organic acid‐rich ground water. Microporosity generated in hydrocarbon contaminated sediments may adversely affect remediation efforts that depend on the efficient injection of electron acceptors into an aquifer or on the recovery of solutes from an aquifer.

Mechanisms of LDL-cholesterol lowering action of psyllium hydrophillic mucilloid in the hamster.

Psyllium hydrophillic mucilloid (psyllium) is a soluble fiber that significantly lowers plasma low-density lipoprotein (LDL)-cholesterol levels in humans and experimental animals. These studies were designed to determine whether this action is the result of a reduction in LDL-cholesterol production, an increase in receptor-mediated LDL clearance by the tissues, or a combination of these mechanisms. Adult male Golden Syrian hamsters were fed ad libitum for 30 days a cereal-based diet containing added cholesterol (0.1%) and hydrogenated coconut oil (10%), as well as either microcrystalline cellulose (Avicel) (7.5%) or psyllium (7.5%). In contrast to their Avicel-fed controls, the hamsters given psyllium had markedly lower plasma total (122.1 +/- 4.1 vs. 399.4 +/- 39.4 mg/dl) and LDL-cholesterol (46.0 +/- 2.2 vs. 143.5 +/- 12.0 mg/dl) levels. Psyllium feeding also prevented both the dramatic increase in hepatic total cholesterol levels (2.6 +/- 0.1 vs. 16.6 +/- 1.1 mg/g), and the suppression of hepatic cholesterol synthesis (165.1 +/- 27.1 vs. 26.1 +/- 1.2 nmol/h per g) that occurred in the animals given Avicel. Compared to their controls, the psyllium-fed animals also manifested a 44% lower rate of LDL-cholesterol production (167.6 +/- 8.1 vs. 300.2 +/- 16.0 micrograms/h per 100 g bw), and a 2.2-fold higher rate of hepatic LDL clearance (50.1 +/- 2.3 vs. 22.6 +/- 2.1 microliters/h per g). When expressed as a percentage of corresponding values obtained for hamsters fed the basal diet without any additions, the relative rate of LDL-cholesterol production was 175 +/- 10% and 99 +/- 4% for the Avicel- and psyllium-fed groups, respectively. It was similarly determined that the level of whole animal relative LDL receptor activity was marginally higher in the hamsters given psyllium (55.9 +/- 1.4%) than in those fed Avicel (47.5 +/- 3.3%). Thus, it was concluded that while the LDL-cholesterol lowering action of psyllium in the hamster is mediated through two mechanisms, the major effect is exerted at the level of LDL-cholesterol production.

Inhibition of Collagen Synthesis in Human Episcleral Fibroblasts by Calcium Ionophore A23187

To test the ability of calcium ionophore A23187 to specifically inhibit collagen biosynthesis in primary cultures of human episcleral fibroblasts obtained at the time of trabeculectomy. Calcium ionophore A23187-treated and untreated (control) cultures were incubated with radiolabeled proline. Radioactivity of collagenasesensitive and -resistant proteins was assayed to determine the rate of collagen production. The relative rate of collagen production as compared to the percent of total protein production decreased by 65% in the cultures treated with 2.0 muM ionophore. Additionally, there was a 78% decrease in absolute collagen production in the treated group. Calcium ionophore A23187 inhibits collagen biosynthesis in cultured human episcleral fibroblasts. It is possible that inhibition of collagen biosynthesis could enhance treatment of ocular fibroproliferative disorders, including episcleral fibroproliferation, a leading cause of glaucoma filtering surgery failure.