Incremental Amounts Research Articles

Monads for incremental computing

This paper presents a monadic approach to incremental computation, suitable for purely functional languages such as Haskell. A program that uses incremental computation is able to perform an incremental amount of computation to accommodate for changes in input data. Recently, Acar, Blelloch and Harper presented a small Standard ML library that supports efficient, high-level incremental computations [1]. Here, we present a monadic variant of that library, written in Haskell extended with first-class references. By using monads, not only are we able to provide a purely functional interface to the library, the types also enforce "correct usage" without having to resort to any type-system extension. We also find optimization opportunities based on standard monadic combinators.This is an exercise in putting to work monad transformers with environments, references, and continuations.

Inhibitory Cross-talk between Estrogen Receptor (ER) and Constitutively Activated Androstane Receptor (CAR): CAR INHIBITS ER-MEDIATED SIGNALING PATHWAY BY SQUELCHING p160 COACTIVATORS

Estrogen receptor (ER) activity can be modulated by the action of other nuclear receptors. To study whether ER activity is altered by orphan nuclear receptors that mediate the cellular response to xenobiotics, cross-talk between ER and constitutive androstane receptor (CAR), steroid and xenobiotic receptor, or peroxisome proliferator-activated receptor gamma was examined in HepG2 cells. Of these receptors, CAR substantially inhibited ER-mediated transcriptional activity of the vitellogenin B1 promoter as well as a synthetic estrogen responsive element (ERE)-containing promoter. Treatment with an agonist of CAR, 1,4-bis-(2-(3,5-dichloropyridoxyl))benzene, potentiated CAR-mediated transcriptional repression. In contrast, an antagonist of CAR, androstenol, alleviated the repression effect. Although CAR interacted with the ER in solution, CAR did not interact with the ER bound to the ERE. CAR/retinoid X receptor bound to the ERE but with much lower affinity than ER. Incremental amounts of CAR elicited a progressive reduction of the ER activity induced by the p160 coactivator glucocorticoid receptor interacting protein 1 (GRIP-1). In turn, increasing amounts of GRIP-1 progressively reversed the depression of ER activity by CAR. An agonist or antagonist of CAR potentiated or alleviated, respectively, the CAR-mediated repression of the GRIP-1-enhanced ER activity, which is consistent with the ability of theses ligands to increase or decrease, respectively, the interaction of CAR with GRIP-1. A CAR mutant that did not interact with GRIP-1 did not inhibit ER-mediated transactivation. Our data demonstrate that xenobiotic nuclear receptor CAR antagonizes ER-mediated transcriptional activity by squelching limiting amounts of p160 coactivator and imply that xenobiotics may influence ER function of female reproductive physiology, cell differentiation, tumorigenesis, and lipid metabolism.

Urinary excretion of duodenal purine derivatives in Kedah-Kelantan cattle

Three male Kedah-Kelantan (KK) cattle each fitted with a ruminal and a T-shaped duodenal cannulae, with an initial body weight of 178.3±5.78 kg were used to study the recovery rate of urinary purine derivatives (PD) after duodenal infusion of incremental amounts of purine bases (PB). During the experiment, the cattle were fed at a maintenance energy level with a diet containing 40% oil palm frond and 60% concentrates. Basal purine flows into the duodenum from the maintenance diet were estimated. Purine bases in the form of adenosine (46%) and guanosine (54%) were infused into the duodenum in four incremental rates equivalent to 10, 15, 30 and 45 mmol purine per day. Urinary allantoin, the principal PD was linearly correlated with PB input, while the contributions of other PD were not affected by treatments. The relationship between daily urinary PD (allantoin, uric acid, hypoxanthine and xanthine) excretion (mmol per day) and duodenal PB flow (mmol per day) was Y=0.847 X+7.146 ( r 2=0.50, P<0.001), suggesting that 0.85 of the supplied exogenous PB were excreted in urine, with an endogenous excretion of 7.15 mmol per day. Urinary PD excretion rates of zebu cattle are similar to those of European cattle.

Optimizing the essential fatty acids, eicosapentaenoic and docosahexaenoic acid, in the diet of the prawn,Penaeus monodon

The dietary requirements of Penaeus monodon for eicosapentaenoic (20:5n-3; EPA) and docosahexaenoic (22:6n-3; DHA) acids were examined. These requirements were examined when dietary levels of linoleic (18:2n-6; LOA) and linolenic acids (18:3n-3; LNA) were also provided at previously established optimal levels of 14 and 21% respectively of the total lipid fatty acids. A 5 × 5 factorial design was used with incremental amounts (0, 4, 8, 12 and 16% of total fatty acids) of EPA and/or DHA. An additional diet containing cod-liver oil was provided as a reference diet. The total lipid content of all of the 25 treatments and reference diets was maintained at the same level of 75 g kg. Growth of prawns fed with the reference diet after 50 days was 244 ± 21%. The greatest response to singular additions of EPA or DHA was with a 12% inclusion of either fatty acid, resulting in 287 ± 21 and 293 ± 18% weight gain, respectively. Growth was generally better when combinations of EPA and DHA were used, the optimal combination being EPA 4% and DHA 4%, resulting in 335 ± 25% weight gain. Addition of high levels of either of the highly unsaturated fatty acids (HUFA) in the diet had a negative effect on growth. Digestibilities of the total neutral lipid and specific fatty acids were examined during the growth trials. The digestibility of total neutral lipid was usually higher when either or both HUFA were present, however there were few significant differences between treatments that contained either or both HUFA. Following the growth trials, digestive glands (DG) of prawns fed with the various diets were analysed to determine the total lipid content and fatty acid composition. Total lipid in the digestive gland increased with the inclusion of DHA, but was not significantly affected by the addition of EPA. The fatty acid composition of the digestive gland lipid generally reflected that of the diet. However, the maximum retention of EPA (11.1% of total DG fatty acids) and DHA (10.7% of total DG fatty acids), was not directly proportional to the amount of either fatty acid present in the diet. These results demonstrate that both EPA and DHA have considerable growth promoting capacity. This growth promoting capacity is enhanced when an optimal balance of both fatty acids are incorporated into the diet.

The Impact of Parks on Property Values: A Review of the Empirical Evidence

The real estate market consistently demonstrates that many people are willing to pay a larger amount for a property located close to a park than for a house that does not offer this amenity. The higher value of these residences means that their owners pay higher property taxes. In many instances, if the incremental amount of taxes paid by each property which is attributable to the presence of a nearby park is aggregated, it is sufficient to pay the annual debt charges required to retire the bonds used to acquire and develop the park. This process of capitalization of park land into the value of nearby properties is termed the “proximate principle.”Results of approximately 30 studies which have empirically investigated the extent and legitimacy of the proximate principle are reported, starting with Frederick Law Olmsted's study of the impact of New York's Central Park. Only five studies were not supportive of the proximate principle and analysis of them suggested these atypical results may be attributable to methodological deficiencies.As a point of departure, the studies' results suggest that a positive impact of 20% on property values abutting or fronting a passive park area is a reasonable starting point. If it is a heavily used park catering to large numbers of active recreation users, then the proximate value increment may be minimal on abutting properties, but may reach 10% on properties two or three blocks away.

Differential scanning calorimetric studies on structured lipids from coconut oil triglycerides containing stearic acid

Triglycerides from coconut oil contain high levels of lauric acid. They were replaced by incremental amounts of stearic acid by interesterification reactions catalyzed by immobilized lipase (IM 60 from Rhizomucor miehei). The reactions were carried out in organic solvents such as hexane. Maximum incorporation of stearic acid was observed by 4 h at 37 °C or by 2 h at 60 °C when triglycerides to fatty acid (stearic acid) ratio was maintained at 1 : 6. The stearic acid level in coconut oil triglycerides was increased from an initial value of 2% to 60% under these conditions. The stearic acid replaced lauric, myristic, and palmitic acids in unmodified triglycerides. A major portion of stearic acid incorporated was found in positions 1 and 3 of triglycerides. Differential scanning calorimetry indicated that stearic acid enrichment increased the solid fat content and also the higher melting polymorphs in modified lipids. The studies also indicated that low melting polymorphic forms of coconut oil triglycerides are converted to higher melting forms by stearic acid enrichment. The modified lipids thus obtained can find use in various food applications.

Vav-2 controls NFAT-dependent transcription inB- but not T-lymphocytes

We show here that Vav-2 is tyrosine phosphorylated following antigen receptor engagement in both B- and T-cells, but potentiates nuclear factor of activated T cells (NFAT)-dependent transcription only in B cells. Vav-2 function requires the N-terminus, as well as functional Dbl homology and SH2 domains. More over, the enhancement of NFAT-dependent transcription by Vav-2 can be inhibited by a number of dominant-negative GTPases. The ability of Vav-2 to potentiate NFAT-dependent transcription correlates with its ability to promote a sustained calcium flux. Thus, Vav-2 augments the calcium signal in B cells but not T cells, and a truncated form of Vav-2 can neither activate NFAT nor augment calcium signaling. The CD19 co-receptor physically interacts with Vav-2 and synergistically enhances Vav-2 phosphorylation induced by the B-cell receptor (BCR). In addition, we found that Vav-2 augments CD19-stimulated NFAT- dependent transcription, as well as transcription from the CD5 enhancer. These data suggest a role for Vav-2 in transducing BCR signals to the transcription factor NFAT and implicate Vav-2 in the integration of BCR and CD19 signaling.

STRAIN ENERGY ASSOCIATED WITH STRUCTURAL MODIFICATIONS

Modifications to linear elastic structures are considered for which the amount of additional stiffening material is increased proportionally. It is proved that, for fixed loading, the strain energy will not be increased and, for fixed displacements, the strain energy will not be decreased by the addition. Furthermore the graphs of strain energy versus the amount of additional material will be monotonic. Also the strain energy absorbed by an incremental amount of additional material must equal the change in the total strain energy for both the cases of fixed loading and fixed displacements. These behavioural properties have been formulated as three theorems. The paper justifies and discusses these and presents some simple illustrations.

The effect of wavelength on the polymerization of multi(meth)acrylates with disulfide/benzilketal combinations

As an alternative to asymmetric iniferters like XDT (p-xylylene bis(N,N-diethyldithiocarbamate), the use of DMPA (2,2-dimethoxy-2-phenylacetophenone) in combination with TED (tetraethylthiuram disulfide) has been proposed as a means of studying living radical polymerizations and creating crosslinked polymers without trapped radicals. This dual initiator system ideally could imitate XDT. The DMPA would photocleave and initiate the reaction via carbon radicals while the TED would photocleave and terminate via dithiocarbamyl (DTC) radicals. In this contribution, we report that for the case of TED and DMPA photoinitiated systems, the nature of the living polymerization and the polymerization kinetics are dependent on the wavelength of light used. Kinetic studies of TEGDMA (triethylene glycol dimethacrylate) photocured with monochromatic light at wavelengths 290, 310, 324, and 365nm were performed using differential scanning calorimetry. TED was added in incremental amounts to determine its effect on the polymerization as a function of wavelength and concentration. The results suggest that termination via DTC radicals becomes more prominent as the irradiating wavelength is increased. A model was developed that incorporates three modes of chain breaking, where carbon–carbon termination, carbon-DTC termination, and chain transfer to TED are all referred to as chain breaking reactions. The model fit the data well after the maximum rate of polymerization. Furthermore, the model predicts that termination involving TED and its derivatives dominates over carbon radical–carbon radical termination when the ratio of TED:DMPA is 1:2 or higher in TED. Therefore, TED:DMPA combinations can be used as an alternative to conventional iniferters as long as a sufficient amount of TED has been added so that carbon–sulfur chain breaking reactions dominate over traditional termination. Infrared analysis of several samples proved that TED:DMPA combinations greater than 1:2 can prevent trapped carbon radicals from persisting in polymer networks after cure.

Etat et évolution de la ressource forestière feuillue en Suisse. Résultats du deuxième inventaire forestier national (IFN 2) | State and Development of Hardwood Resources in Swiss Forests – Results of the Second National Forest Inventory (NFI 2)

The results of the second national forest inventory (NFI 2) allow a reliable and comprehensive assessment of the Swiss forests'development for the first time. One of the most obvious changes is the important increase in hardwoos. The most significant facts of NFI for hardwood-resources are presented as the basis for discussions and measures for an increased hardwood utilisation. The whole stock in Swiss forests amounts to 418 Mio m3. About 60% of the hardwood stock of 118 Mio m3 is beech. The share of hardwood has increased by 2% both in surface and growing stock. These developments will remain constant in the future. The increase in stock amounts to 5% in softwood,whereas the one of hardwood amounts to 12%, maple and ash are dominating. The most important increase in standing volume is evident in trees of 36 to 52 cm DBH. With an unchanged utilisation, the share in large timber will further increase. The increase was harvested to 80% in softwood, to 59% in hardwood, less so, however, in the French part than in the rest of Switzerland. But in the distinct cantons, not more than 40 to 80% of the increment of hardwood has been harvested. In hardwood, the non-exploited increment amounts to 1.4 Mio m3per year, of which 58% is beech, almost as the growing stock. For silvicultural reasons, it would be possible to double the volume of exploited hardwood – which would make sense, too,for ecological and socio-economic reasons. However, the calculated harvest expenditure for such an increased utilisation is in most of the cases high above the present average proceeds for hardwood.

Effect of dietary concentration of metabolizable lysine on finishing cattle performance.

A finishing trial and a metabolism trial were conducted to determine the effect of supplemental metabolizable Lys level on finishing calf performance and to estimate the metabolizable Lys requirement of finishing calves. The finishing trial included 60 individually fed crossbred beef steer calves (237 kg; SD = 20 kg) supplemented with either incremental amounts of rumen-protected Lys and Met, or Met alone. Addition of Lys and Met improved gains and efficiencies (quadratic; P < .02) during the first 56 d. There was no response to supplemental Met alone, suggesting that supplemental Lys rather than Met was responsible for the improvement in performance. Using nonlinear analyses to compare gain relative to supplemental Lys intake, maximum gain was determined to be 2.10 kg/d, or .27 kg/d above the zero Lys control, at a supplemental Lys intake of 2.56 g/d. Steers supplemented with 3 and 4 g of Lys had a weight advantage over the control steers of 16 kg at 56 d and 32 kg at the end of the 161-d trial. However, there were no statistical responses to Lys or Met during any periods after 56 d. During a separate metabolism trial, four steers fed the control finishing diet were slaughtered, and abomasal contents were collected for amino acid analyses. The predicted (Level 1 NRC, 1996) metabolizable protein flow to the abomasum for the control diet was 715 g/d, and the predicted Lys flow was 37.9 g/d. A supplemental Lys intake of 2.56 g/d would increase the Lys flow to 40.5 g/d. Feedlot diets low in ruminal escape protein may be deficient in metabolizable Lys, especially early in the feeding period. The metabolizable Lys requirement of steer calves gaining 2.10 kg/d is estimated to be 40.5 g/d.

Evaluation of feather meal as a source of sulfur amino acids for growing steers.

In situ and digestion studies were conducted to evaluate feather meal (FTH), blood meal (BM), and meat and bone meal (MBM) for escape protein content, amino acid composition of the escape protein, true protein digestibility, and digestibility of the individual amino acids. Following 12 h of ruminal incubation, escape protein values were 73.5, 92.4, and 60.8% of CP for FTH, BM, and MBM, respectively. Blood meal and MBM were poor sources of sulfur amino acids (SAA), whereas FTH was a good source. Most of the SAA of FTH, however, was Cys, with very little Met. True protein digestibilities were not different for the protein sources (P > .15), ranging from 86.7 to 94.0% of the CP. However, digestibilities of the individual amino acids were quite different. Two growth studies were conducted to evaluate FTH as a source of SAA for growing cattle. The first study used 120 steers (228 +/- 15 kg) supplemented with urea, MBM, MBM plus 1% FTH, or MBM plus 2% FTH. Additionally, incremental amounts of rumen-protected Met were added to treatments containing MBM. Supplementation of MBM increased (P < .05) ADG compared with the urea control. Addition of FTH to MBM resulted in a linear (P < .01) increase in ADG. However, addition of rumen-protected Met to MBM plus FTH treatments further improved gains. Although FTH is an effective source of SAA, Met probably was first-limiting. The second study used 90 steers (243 +/- 18 kg) supplemented with BM plus incremental amounts of SAA from either FTH or rumen-protected Met. Addition of SAA improved ADG compared with BM alone (P < .05). Rumen-protected Met as a source of SAA improved ADG compared with FTH (P < .05). The SAA from FTH promoted a gain response equal to 50% of the response obtained with rumen-protected Met. Formulation of ruminant diets for metabolizable amino acids must account for escape value and digestibility of each individual amino acid. Feather meal is an effective source of SAA; however, Cys supplies over five times the amount supplied by Met.

Metabolize methionine and lysine requirements of growing cattle.

Two growth studies were conducted to determine the Met and Lys requirements of growing cattle. In each 84-d trial, steer calves were fed individually diets containing 44% sorghum silage, 44% corn cobs, and 12% supplement (DM basis) at an equal percentage of BW. In Trial 1, 95 crossbred steers (251 kg) were supplemented with urea or meat and bone meal (MBM). Incremental amounts of rumen-protected Met were added to MBM to provide 0, .45, .9, 1.35, 3, and 6 g/d metabolizable Met. In Trial 2, 60 steers (210 kg) were supplemented with urea or corn gluten meal (CGM). Incremental amounts of rumen-protected Lys were added to CGM to provide 0, 1, 2, 3, 4, 5, 6, 8, and 10 g/d metabolizable Lys. Supplementation with MBM and CGM increased the supply of metabolizable protein to the animal. Steers fed MBM plus 0 Met gained 49 g/d more than steers fed urea, whereas steers fed CGM plus 0 Lys gained 150 g/d more than steers fed urea. Supplementation of rumen-protected Met and Lys improved ADG in steers fed MBM and CGM, respectively (P < .10). Nonlinear analysis, comparing gain vs supplemental Met and Lys intake, predicted supplemental Met and Lys requirements of 2.9 and .9 g/d, respectively. This amount of additional Met promoted .13 kg/ d gain greater than MBM alone, and this amount of additional Lys promoted .10 kg/d gain greater than the CGM alone. Metabolizable Met and Lys requirements were predicted from Level 1 of NRC (1996) calculated metabolizable protein supply, amino acid analysis of abomasal contents, and the maximum response to supplemental AA. Steers gaining .39 kg/d required 11.6 g/ d Met or 3. 1% of the metabolizable protein requirement, whereas steers gaining .56 kg/d required 22.5 g/d Lys or 5.7% of the metabolizable protein requirement.

The anhydrous milk fat, ghee, lowers serum prostaglandins and secretion of leukotrienes by rat peritoneal macrophages

Ghee, the anhydrous milk fat, is one of the most important sources of dietary fat in India. Male Wistar rats were fed diets containing 2.5, 5.0 and 10 wt% ghee for a period of 8 weeks. The diets were made isocaloric with groundnut oil. The results showed that serum thromboxane levels decreased by 27–35%, and 6-keto- prostaglandin F1αby 23–37% when ghee was incorporated at level of 10% in the diet. Prostaglandin E2levels in serum and secretion of leukotrienes B4C4and D4by peritoneal macrophages activated with calcium ionophore decreased when increased amounts of ghee from 2.5 to 10% were included in the diet. Arachidonic acid levels in macrophage phospholipids decreased when incremental amounts of ghee were fed to rats. These studies indicate that ghee in the diet not only lowers the prostaglandin levels in serum but also decreases the secretion of leukotrienes by macrophages.

Topical Psoralen-Ultraviolet A Therapy for Palmoplantar Dermatoses: Experience With 35 Consecutive Patients

To report the effectiveness of topical psoralen-ultraviolet A (PUVA) therapy for palmoplantar dermatoses and to describe our method of administration of this treatment modality. We conducted a retrospective study of 35 patients, 27 to 66 years of age, who received topical hand and foot PUVA therapy. Ten patients had psoriasis vulgaris, 8 had pustular psoriasis, 5 had dyshidrotic eczema, and 12 had other types of dermatitis. The affected area was soaked in a psoralen solution, 0.0005% methoxsalen (10 mg of methoxsalen in 2 L of warm water), for 30 minutes and then exposed to incremental amounts of ultraviolet A light three times weekly until the dermatosis subsided or cleared. Treatment frequency was then reduced and ultimately discontinued. Time to maximal improvement of the hands and feet was defined as the period from the beginning of PUVA treatment to the point at which the frequency of treatment was reduced from three times weekly to twice weekly. Fourteen patients (40%) had clearing of their disease, and 14 others (40%) had improvement of their conditions. The mean time to clearing was 2.8 months (range, 2 weeks to 7 months), and the mean number of treatments was 27.3 (range, 10 to 55). The mean total dose of ultraviolet A received was 140 J/cm2 (range, 9 to 530). Two patients (6%) had no response to treatment. Mild localized ultraviolet-related erythema developed in 16 patients (46%). Five patients "dropped out" of treatment, and nine other patients discontinued treatment during maintenance therapy. The principal reason cited was inconvenience. Topical PUVA therapy is an effective and safe treatment option for recalcitrant dermatoses affecting the palms and soles.

Asymptotic MAP criteria for model selection

The two most popular model selection rules in signal processing literature have been Akaike's (1974) criterion (AIC) and Rissanen's (1978) principle of minimum description length (MDL). These rules are similar in form in that they both consist of data and penalty terms. Their data terms are identical, but the penalties are different, MDL being more stringent toward overparameterization. AIC penalizes for each additional model parameter with an equal incremental amount of penalty, regardless of the parameter's role in the model, In most of the literature on model selection, MDL appears in a form that also suggests equal penalty for every unknown parameter. This MDL criterion, we refer to as naive MDL. In this paper, we show that identical penalization for every parameter is not appropriate and that the penalty has to depend on the model structure and type of model parameters. The approach to showing this is Bayesian, and it relies on large sample theory. We derive maximum a posteriori (MAP) rules for several different families of competing models and obtain forms that are similar to AIC and naive MDL. For some families, however, we find that the derived penalties are different. In those cases, our extensive simulations show that the MAP rule outperforms AIC and naive MDL.

The effect of incorporation of rye flour on the quality of oriental noodles

Salted noodles were prepared using Canadian Western Red Winter (CWRW) or Canadian Western Red Spring (CWRS) patent flours augmented with 15, 30 and 50% rye flour. Addition of incremental amounts of rye flour resulted in significant decreases in both raw and dried noodle brightness, L *, and yellowness, b *. In addition, dry noodle breaking strength, cooked noodle firmness, (MCS), and chewiness (REC) also decreased with increasing rye content. However, an acceptable wheat:rye noodle was still possible with a rye incorporation of 30%. Proportional substitution of high gluten strength flour from the Canadian Western Extra Stron (CWES) class of wheat in exchange for CWRW flour had no significant impact on noodle color but did significantly ( p⩽0.05) improve the textural attributes, especially firmness, of the 70:30 wheat:rye blended noodles. The addition of peroxide at a 0.5% concentration was found to significantly improve wheat:rye blended noodle brightness and firmness. The use of peroxidase in the presence or absence of peroxide had no impact on the wheat:rye noodle quality characteristics.

Electrical resistivity behavior of high salinity brine suspensions

Resistivities of various suspensions, prepared by adding incremental amounts of rock powder materials (< 62 μm) in NaCl brines of different salinities ranging from 10 to 200 kppm, were measured and compared. Results indicated a linearly increasing suspension resistivity with increasing volume of solid particles, on a semilogarithmic scale. Except for Wyoming bentonite, the relationships between the resistivity and volume of particles were similar for all materials measured at different brine salinities. An Archie-type linear relationship was observed between the suspension resistivity factor, which is the ratio of the suspension resistivity to the brine resistivity, and the fractional brine volume of the suspension. The slopes m of the linear relationships on log-log plots were comparable for all samples. The average slope was 1.708. The Wyoming bentonite exhibited different characteristics. Elimination of surface conductivity by using high salinity brines and increase of tortuosity due to the association of clay particles probably account for the higher slope (m = 2.852) for Wyoming bentonite.

Excretion of Purine Derivatives by Holstein Cows Abomasally Infused with Incremental Amounts of Purines

Five multiparous, ruminally cannulated Holstein cows (two lactating and three dry) weighing (X¯±SD) 667±35kg were used to study the effect of abomasal purine infusion on the excretion of purine derivatives. Cows were fed corn silage four times daily at 90% of ad libitum intake (X¯ = 9.16kg of dry matter/d). Purines were infused into the abomasum as brewer's yeast suspensions in five incremental amounts (0 to 380 mmol/d) during five experimental periods according to a 5 × 5 Latin square design. Periods were 7 d; purine infusions were conducted during the last 4 d, and urine was collected during the last 3 d of each period. Ruminal purine outflow in all cows was measured during an experimental period immediately preceding and immediately following the five infusion periods and in each cow during the 0-mmol/d infusion period of the experiment. The relationship between total (milk plus urine) daily excretion of purine derivatives (allantoin plus uric acid) and total (abomasal infusion plus ruminal outflow) daily purine flow was quantified by linear regression analysis and was described by the relationship: Y = 0.856X + 103 (r2 = 0.93). The slope (0.856) indicated that 86% of purines that reached the omasum were excreted as purine derivatives. In the two lactating cows, urinary purine derivatives accounted for 98.4% of the total purine derivatives that were excreted. Ruminal flow of microbial CP can be estimated from the CP:purine ratio of ruminal microorganisms and the excretion of purine derivatives.

Cotton Cleanability: Part I: Modeling Fiber Breakage

Cotton's ability to open and release its foreign matter in response to mechanical cleaning treatments is a crucial concern for the textile processing industries. This work is part of a series in which a comprehensive approach to cotton quality in textile processing is developed. The theme is that processing quality is expressed in terms of a trade-off between reduction in foreign matter on the one hand and accumulation of fiber damage on the other. This trade-off between cleaning and damage governs the efficiency of manufacture as well as the quality of the textile product. In order to optimize the processing, it is necessary to be able to measure and interpret this tradeoff; this requires practical methods for quantifying both cleaning and damage. Since the principal overt manifestation of processing damage to cotton is fiber breakage, it is essential to have a methodology for measuring and interpreting incremental amounts of fiber breakage. This study presents a model of fiber breakage that relates the fundamental nature of breakage processes to the observable differences between the length distribution of fibers going into and coming out of a specific processing stage, such as a single machine. This technique is demonstrated with length data derived from the Peyer TexLab instrument system.