Can lay-led walking programmes increase physical activity in middle aged adults? : a randomised controlled trial

Study objective: To compare health walks, a community based lay-led walking scheme versus advice only on physical activity and cardiovascular health status in middle aged adults. Design: Randomised controlled trial with one year follow up. Physical activity was measured by questionnaire. Other measures included attitudes to exercise, body mass index, cholesterol, aerobic capacity, and blood pressure. Setting: Primary care and community. Participants: 260 men and women aged 40–70 years, taking less than 120 minutes of moderate intensity activity per week. Main results: Seventy three per cent of people completed the trial. Of these, the proportion increasing their activity above 120 minutes of moderate intensity activity per week was 22.6% in the advice only and 35.7% in the health walks group at 12 months (between group difference =13% (95% CI 0.003% to 25.9%) p=0.05). Intention to treat analysis, using the last known value for missing cases, demonstrated smaller differences between the groups (between group difference =6% (95% CI -5% to 16.4%)) with the trend in favour of health walks. There were improvements in the total time spent and number of occasions of moderate intensity activity, and aerobic capacity, but no statistically significant differences between the groups. Other cardiovascular risk factors remained unchanged. Conclusions: There were no significant between group differences in self reported physical activity at 12 month follow up when the analysis was by intention to treat. In people who completed the trial, health walks was more effective than giving advice only in increasing moderate intensity activity above 120 minutes per week

The quality of butter made from Vacuum-pasteurized and Vat-pasteurized lots of the same creams

During the past few years a large amount of butter manufactured in the Middle West has been criticised for weedy flavors. This increase in weedy flavors unquestionably has resulted from a number of successive dry years. Some of the most common weed defects in this section are wild onion (Allium cernuum) , ragweed (Ambrosia artemisiifolia L.) and dog fennel (Anthemis cotula L.). The defects resulting from skunk cabbage (Symplocarpus foetidus (L.)), french weed (Thalaspi arvense L.) and peppergrass (Lepidium verginicum L.) (2) are apparently less common. Feed flavors are more important than weed flavors in this section. It has been recognized for some time that silage and alfalfa hay, when fed to dairy herds in fairly large quantities, cause definite milk flavors that are apparent in the butter. Changes in feeding procedures designed to lower fat production costs have, in many cases, increased the problems of the buttermaker. Sweet clover, rye pasture, wheat pasture, soybean hay and cane silage, flavor milk to such an extent that they affect the quality of the resulting butter

Iowa Butter- Vitamin Rich

Folks who eat Iowa butter in generous amounts are rather sure to be getting a great deal of that important vitamin— vitamin A

Chemistry of butter and butter making I. A comparison of four methods for the analysis of butter with an explanation of a discrepancy found to exist in the fat determinations

1. A modification of the A. O. A. C. method for complete butter analysis is described. The method is considered applicable for use in control laboratories, in which eight or more samples are analyzed at a time. 2. This method, together with the Kohman and Mojonnier analyses for butter, was compared with the A. O. A. C. method as a standard. The modified official and the Kohman methods check closely with the A. O. A. C. method for all constituents of butter. With the 50 samples analyzed in duplicate the fat content was 0.22 percent lower by the Mojonnier method (abnormal values not included-see table I ) than by the A. O. A. C. method. About 10 percent of the Mojonnier analyses varied widely from the duplicates and from the A. O. A. C. method. 3. The variation between duplicates is attributed (a) to peculiarities in the emulsification of the fat in the extraction flasks, which caused incomplete extraction, and (b) to a blowing out of ether-fat solution around the stoppers when these were removed or to both. 4. Data are presented which show that the value by which normal Mojonnier fat determinations are lower than the A. O. A. C. method is equivalent to the fatty acids, which are not extracted in the Mojonnier procedure but which appear as fat with the A. O. A. C. analysis. It is further shown that this difference was larger, as the rancidity of the butter increased. 5. The modified official method is a rapid method and is considered sufficiently accurate for the analysis of good quality butter in control laboratory work. Likewise the A. O. A. C. method is considered to be accurate as an analytical standard for the analysis of good quality butter. The Kohman method as outlined is a rapid method sufficiently accurate for plant use. All three methods give values for fat which are too high by an appreciable amount for the analysis of rancid butter. 6. The Mojonnier and the la-gram extraction methods give a closer approximation of the true fat value of rancid butter than do the dry extraction methods (A. O. A. C., modified official and Kohman)

Rapid acid tests for cream

The Farrington rapid acid test has been employed for many years by the fluid milk industry for grading samples on the borderline of acidity set for their purchase. In performing the test, neutralizing solutions (containing phenolphthalein) used are of such strength that 1 dipper of solution added to 1 dipper (of the same size) of milk gives a pink mixture if the milk is 0.1 percent acid or less; 2 dippers of neutralizing solution grade at the 0.2 percent point and so on. By adjusting the neutralizing strength the grades corresponding to 1 and 2 dippers of neutralizing solution to 1 of milk can be made 0.2 and 0.4 percent, respectively, instead of 0.1 and 0.2 percent. This is the strength of the solution used for cream grading

The effect of processing, handling and of testing procedures on the fat content of ice cream

A number of inquiries received from Iowa ice cream manufacturers shows that they believe that some steps in the processing or handling of ice cream cause a lower fat percentage in the frozen product than in the mix. From a theoretical viewpoint, no such fat lowering should occur in the product. A sufficient number of inquiries has been received, however, to warrant studying the causes of any irregularities which might result from the processing and the handling of the mix and of the frozen ice cream, and likewise, any winch might be introduced by the methods of obtaining and mixing the samples, by the methods of analysis employed or by the analytical apparatus used. For the sake of convenience the problem was divided into eight sections: 1. The effect of the temperature at which the samples were weighed, 2. a comparison of some Babcock modifications for ice cream testing, 3. the effect of the type of test bottle used, 4. the effect of aging and freezing, 5. the effect of hardening and retail handling, 6. variations that may occur in a single mix, 7. a comparison of tests made with samples taken in the frozen and in the melted state, and 8. a comparison of the test of the mix with those of the frozen ice cream, the scrapings from the dasher and the scrapings from the freezer sides

The preparation of a Non-Desiccated Sodium Caseinate Sol and its use in ice cream

1. The body and texture of ice cream are improved by the replacement of dry skimmilk by sodium caseinate sols. This improvement was shown up to 2.5 to 5.0 percent replacement, depending on the composition of the mix. 2. The flavor of ice cream was progressively improved by the replacement of dry skimmilk by sodium caseinate sols up to 3 to 4 percent replacement, depending on the composition of the mix. 3. This flavor improvement was due to the careful pH control used in the preparation of the sodium caseinate sols. 4. The type of melting of the ice cream was altered by the replacement of dry skimmilk by sodium caseinate sols. 5. The use of sodium caseinate sols increased the initial and maximum overrun and decreased the whipping time of the ice creams produced. 6. The curves for whipping time show that from 1.5 to 3.0 percent replacement of dry skimmilk by the sodium caseinate sols is necessary to effect sufficient improvement in whip to warrant their use. A 3 percent replacement would be necessary with a mix containing 14 percent fat and 10 percent serum solids. 7. The use of sodium caseinate preparations as additional solids, i.e., in addition to the amounts of serum solids (8 to 10 percent) commonly used by the trade, has been suggested. The amounts of milk protein that would be required to yield sufficient improvement in whip and in body and texture score would, in the light of the figures presented, be large enough to make their use questionable

Chemistry of butter and butter making IV. The relationships among the cream acidity, the churning loss and the churning time

1. The influence of acidity, developed in cream that had been pasteurized while sweet and subsequently ripened, was studied over a pH range (in the buttermilk) from 4.5 to 7.0. 2. Three series of creams, viz., 20, 30 and 37.5 percent fat, were investigated. 3. The losses (calculated as percentage of the total fat) for all three series varied little in the pH range 7.0 to 5.5. In this region the least variation was encountered with 30 percent cream; such tendency in loss changes as was exhibited by 30 percent cream was toward a decreasing loss with decreasing pH, while the 37.5 percent cream losses tended to pass through a. minimum at pH 6.3 to 6.4. From pH 5.5 to pH 4.8 or 4.9 the losses rose to maxima (at 4.8 to 4.9) with 20 and 37.5 percent cream; a slight rise with no definite maximum at pH 4.8 to 4.9 occurred with 30 percent cream. With all three creams a marked change of function in the curves (loss vs. pH of buttermilk) occurred at pH 4.8 to 4.9; the loss dropped sharply and in practically linear fashion from that point to pH 4.5. 4. The above facts (especially the maximum at pH 4.8 to 4.9) were interpreted as indicating that casein plays an important role in the protection of the fat globules in cream, if the churning loss is taken as a measure of protective action. 5. The churning loss data correlated very well with electro-kinetic potentials of the fat globules, determined by Sommer and North and re-presented here. 6. Churning times show closer correlation with pH of buttermilk the lower the fat test of the cream. Other factors such as change in protein to fat ratio, increased viscosity, greater ease of whipping, lower specific gravity, etc., may be involved in affecting the churning times of the richer creams. 7. Churning time data in this and the third bulletin of this series indicate that, if the fat and serum in cream are in proper physical state and chemical equilibrium, no hard and fast rule can be drawn that long or short churning times must be associated with high losses. 8. Data show that the fat test of the buttermilk in low fat (18 to 20 percent), highly ripened creams (pH 4.5 to 4.6) is considerably lower than those for high fat (30 to 37.5 percent), sweet cream (pH 6.5). Calculated as the percentage of the total fat churned, however, the low fat, highly ripened cream losses are approximately equivalent to those for 30 percent sweet cream and are slightly higher than those for 37.5 percent sweet cream. This shows that the American, Australian and New Zealand churning losses compare very favorably with those obtained in Denmark, Germany and Holland. 9. Based on the data presented and others from the literature it was hypothecated that the protective action at the fat globule interface was caused by two types of protective materials- one labile and one non-labile. The latter is closely associated with the fat, presumably on the fat side of the interface, and consists of a protein-phospholipin complex. The former is oriented from the water side of the interface and is composed of all the surface tension lowering constituents of the serum. Of the serum constituents casein probably plays the most important protective role as indicated by certain dairy phenomena. 10. If the validity of the hypothesis presented is assumed, the following explanation of the churning process seems logical: Utilization of the labile protective materials, to stabilize foam interfaces, decreases their concentration at the fat-serum interface. When the labile to non-labile protective material ratio is sufficiently small that the fat globules are in an unstable state, they merge and lose their identity. This merger weakens the forces at the force centers of the fat globules to such an extent that the non-labile materials are released from the fat globule surfaces and are incorporated in the buttermilk, while the fat unites to form butter

Application of the Gillespie algorithm to a granular intruder particle

We show how the Gillespie algorithm, originally developed to describe coupled chemical reactions, can be used to perform numerical simulations of a granular intruder particle colliding with thermalized bath particles. The algorithm generates a sequence of collision ``events'' separated by variable time intervals. As input, it requires the position-dependent flux of bath particles at each point on the surface of the intruder particle. We validate the method by applying it to a one-dimensional system for which the exact solution of the homogeneous Boltzmann equation is known and investigate the case where the bath particle velocity distribution has algebraic tails. We also present an application to a granular needle in bath of point particles where we demonstrate the presence of correlations between the translational and rotational degrees of freedom of the intruder particle. The relationship between the Gillespie algorithm and the commonly used Direct Simulation Monte Carlo (DSMC) method is also discussed.Comment: 13 pages, 8 figures, to be published in J. Phys. A Math. Ge

Multiscale modeling and simulation for polymer melt flows between parallel plates

The flow behaviors of polymer melt composed of short chains with ten beads between parallel plates are simulated by using a hybrid method of molecular dynamics and computational fluid dynamics. Three problems are solved: creep motion under a constant shear stress and its recovery motion after removing the stress, pressure-driven flows, and the flows in rapidly oscillating plates. In the creep/recovery problem, the delayed elastic deformation in the creep motion and evident elastic behavior in the recovery motion are demonstrated. The velocity profiles of the melt in pressure-driven flows are quite different from those of Newtonian fluid due to shear thinning. Velocity gradients of the melt become steeper near the plates and flatter at the middle between the plates as the pressure gradient increases and the temperature decreases. In the rapidly oscillating plates, the viscous boundary layer of the melt is much thinner than that of Newtonian fluid due to the shear thinning of the melt. Three different rheological regimes, i.e., the viscous fluid, visco-elastic liquid, and visco-elastic solid regimes, form over the oscillating plate according to the local Deborah numbers. The melt behaves as a viscous fluid in a region for $\omega\tau^R\lesssim 1$, and the crossover between the liquid-like and solid-like regime takes place around $\omega\tau^\alpha\simeq 1$ (where $\omega$ is the angular frequency of the plate and $\tau^R$ and $\tau^\alpha$ are Rouse and $\alpha$ relaxation time, respectively).Comment: 13pages, 12figure