An assessment of the incidence of punctures in latex and non-latex dental examination gloves in routine clinical practice

OBJECTIVE: To investigate the puncture resistance of a recently introduced non-latex, nitrile dental glove in comparison with a latex glove worn during routine clinical dental procedures. SETTING: Dentists in general dental practice working within the UK during 1999. SUBJECTS AND METHODS: 2,020 gloves worn by five general dental practitioners were examined for punctures following standard clinical use by a water inflation method. Procedures undertaken during glove usage and length of time worn were recorded. RESULTS: Following clinical use, 1.9% of the latex gloves and 5.3% of the nitrile gloves had punctures, a statistically significant difference (P less than 0.0001). The puncture resistance of the nitrile gloves was superior to the puncture resistance of previously tested worn non-latex (vinyl) gloves. There was no evidence of a statistically significant difference between operators for the percentage or incidence of punctured gloves (P = 0.787) after correcting for glove type. No statistically significant difference was noted between incidence of puncture in the control, unused gloves (n = 200 for each type) and the gloves examined following clinical use (P = 0.907 for nitrile, P = 0.613 for latex). CONCLUSION: No increase in the number of punctures was noted following clinical use for either glove type. This could be considered to indicate good puncture resistance of the gloves tested in clinical use

Evaluation of fermented whole crop wheat, urea-treated processed whole crop wheat and maize silage for dairy cows

End of Project ReportThere has been increased interest in and increased usage of forages other than grass silage for feeding dairy cows during the winter period. This has arisen because of the inconsistency in making good quality grass silage and the low intake characteristics of this feed. The main objective of this project was to evaluate the effects on dairy cow intake and performance of offering fermented whole crop wheat (WCW) silage, urea-treated processed WCW and maize silage in mixtures with grass silage compared with grass silage alone. The value of these feeds as supplements to grazed grass in the Autumn for late lactation spring calving cows and their effect on dietary nitrogen (N) utilisation for milk protein production were also investigated. The first two experiments evaluated the effects of including 67% of the forage mixture on a dry matter (DM) basis as fermented WCW, urea-treated processed WCW (also known as “Alkalage”) or maize silage in comparison to grass silage alone in the diet of autumn calving cows. The fermented WCW and urea-treated processed WCW were harvested at a stubble height of approximately 20 cm. Sixty and 95% of the grain was milled/cracked in the urea-treated processed WCW in experiments 1 and 2, respectively. Forages were supplemented with concentrates of varying crude protein (CP) concentrations so as to maintain a similar CP concentration in the total dietary dry matter across treatments. In both experiments all the feeds were well preserved. The DM (g/kg) and starch contents (g/kg DM) in the fermented WCW, urea-treated processed WCW and maize silage in experiments 1 were 406 and 282, 733 and 324, 221 and 140 and in experiment 2 were 370 and 323, 763 and 341 and 302 and 324, respectively. Results from both experiments were similar. The three forage mixtures resulted in greater DM intake and greater fat plus protein production than grass silage. The largest effect on intake was obtained with the urea-treated processed WCW which probably reflected the greater DM content of this forage mixture compared with the others. Milk protein content was generally similar across the three forage mixtures and greater than on grass silage as the sole forage. In the third experiment short-straw urea-treated processed WCW (harvested at a stubble height of 35 cm) was evaluated in comparison to the fermented WCW (harvested at a stubble height of 20 cm), maize silage and grass silage. The DM (g/kg) and starch (g/kg DM) contents in the fermented WCW, urea-treated processed WCW and maize silage were 389 and 316, 795 and 382 and 346 and 301, respectively. Fifty nine percent of the grain was cracked/processed in the urea-treated processed UP-WCW .Level of inclusion of forages in the diets was the same as in the first two experiments and total dietary CP was again maintained at a similar concentration across treatments by offering concentrates of varying CP concentrations. The higher harvesting height of the urea-treated processed WCW resulted in a greater starch concentration in this feed in comparison to the first two experiments. The results however were very similar to those obtained in the first two experiments with the forage mixtures again increasing DM intake and fat plus protein yield. Inclusion of the short-straw urea-treated processed WCW did not result in greater fat plus protein production compared with the inclusion of fermented WCW or maize silage. The greatest efficiency of conversion of dietary nitrogen (N) to milk N was achieved with the maize silage mixture and the least efficiency with the urea-treated process WCW mixture. In experiment 4 the nutritive value of fermented WCW, urea-treated processed WCW and maize silage were evaluated in comparison to a concentrate as supplements to grazed grass for spring calving cows in the autumn. A treatment with a high grass allowance of 24 kgDM (> 4 cm)/cow per day was also included while the grass allowance on the supplemented treatments was restricted to 17 kgDM (> 4 cm)/cow per day. All the supplemented treatments and the high grass allowance treatment gave greater milk yields than the unsupplemented restricted grass treatment. The concentrate supplement resulted in the greatest solids corrected milk yield and this was greater than any of the forage supplemented treatments which were not significantly different from one another. In the final experiment the output of N in milk, urine and faeces was measured when grass silage, fermented WCW, urea-treated processed WCW and maize silage were fed as the sole forages plus 6 kg of a concentrate containing 338 g crude protein/kg DM. The proportion of consumed N excreted in urine and faeces was greatest on grass silage and urea-treated processed WCW with fermented WCW and maize silage resulting in the greatest proportion of consumed N being excreted in milk. Overall, the project demonstrated that including either type of WCW or maize silage with grass silage increased fat plus protein production and protein concentration to a similar extent compared to grass silage as the sole forage. All three forages increased DM intake with the greatest increase observed with urea-treated processed WCW. Because of this greater intake resulting in similar fat plus protein production conversion of dietary DM to milk solids was less efficient on urea-treated processed WCW based diets than on fermented WCW or maize silage based diets. Grass silage and urea-treated processed WCW based diets were least N efficient with less dietary N being incorporated into milk N than on fermented WCW or maize silage based diets. Comparing the responses on the forage mixtures relative to one another and to grass silage across experiments 1 to 3 indicates that neither degree of grain processing or harvesting height (within the ranges studied here) are of substantial importance in determining the nutritive value of urea-treated processed WCW. All of the three alternative forages gave similar solids corrected milk yield responses when used as buffer feeds for spring calved cows at pasture in the autumn but these responses were less than 50% of the response to a concentrate supplement

Drawings as a Component of Triangulated Assessment

Action research (AR) in an educational setting as described by Tillotson (2000) is an approach to “classroom-based problems” or “specific school issues” (p. 31). His process involves identification of the issue or problem, development and implementation of an action plan, gathering and interpreting data, sharing the results within the community, and “action planning” as a cyclical endeavor (Tillotson, 2000, p. 32). AR is utilized as a key component of developing pre-service teachers in the University of Michigan-Dearborn certification program. Illustrating the five components of Tillotson’s approach, pre-service elementary teachers develop and analyze pre-assessments of K-8 student knowledge about a specific science topic to identify prior student understanding; they create and teach two lessons to provide applicable scientific content, post-assess to determine the impact of their teaching and write a research journal style report describing their project. The AR assignment is more structured than a typical action research project in order to support the pre-service teachers, many whom have never conducted a literature review, created assessments linked to research, or completed an AR project (Luera & Otto, 2005)

Non-Equilibrium Statistical Physics of Currents in Queuing Networks

We consider a stable open queuing network as a steady non-equilibrium system of interacting particles. The network is completely specified by its underlying graphical structure, type of interaction at each node, and the Markovian transition rates between nodes. For such systems, we ask the question ``What is the most likely way for large currents to accumulate over time in a network ?'', where time is large compared to the system correlation time scale. We identify two interesting regimes. In the first regime, in which the accumulation of currents over time exceeds the expected value by a small to moderate amount (moderate large deviation), we find that the large-deviation distribution of currents is universal (independent of the interaction details), and there is no long-time and averaged over time accumulation of particles (condensation) at any nodes. In the second regime, in which the accumulation of currents over time exceeds the expected value by a large amount (severe large deviation), we find that the large-deviation current distribution is sensitive to interaction details, and there is a long-time accumulation of particles (condensation) at some nodes. The transition between the two regimes can be described as a dynamical second order phase transition. We illustrate these ideas using the simple, yet non-trivial, example of a single node with feedback.Comment: 26 pages, 5 figure

A deficit of high-redshift, high-luminosity X-ray clusters: Evidence for a high value of Ωm?

From the Press-Schechter mass function and the empirical X-ray cluster luminosity-temperature (L-T) relation, we construct an X-ray cluster luminosity function that can be applied to the growing number of high-redshift, X-ray cluster luminosity catalogs to constrain cosmological parameters. In this paper, we apply this luminosity function to the Einstein Medium Sensitivity Survey (EMSS) and the ROSAT Brightest Cluster Sample (BCS) luminosity function to constrain the value of Ωm. In the case of the EMSS, we find a factor of 4-5 fewer X-ray clusters at redshifts above z = 0.4 than below this redshift at luminosities above LX = 7 × 1044 ergs s-1 (0.3-3.5 keV), which suggests that the X-ray cluster luminosity function has evolved above L(Black star). At lower luminosities, this luminosity function evolves only minimally, if at all. Using Bayesian inference, we find that the degree of evolution at high luminosities suggests that Ωm = 0.96+0.36-0.32, given the best-fit L-T relation of Reichart, Castander, & Nichol. When we account for the uncertainty in how the empirical L-T relation evolves with redshift, we find that Ωm ≈ 1.0 ± 0.4. However, it is unclear to what degree systematic effects may affect this and similarly obtained results

Structural equation modeling reveals determinants of fitness in a cooperatively breeding bird

Even in well-studied organisms, it is often challenging to uncover the social and environmental determinants of fitness. Typically, fitness is determined by a variety of factors that act in concert, thus forming complex networks of causal relationships. Moreover, even strong correlations between social and environmental conditions and fitness components may not be indicative of direct causal links, as the measured variables may be driven by unmeasured (or unmeasurable) causal factors. Standard statistical approaches, like multiple regression analyses, are not suited for disentangling such complex causal relationships. Here, we apply structural equation modeling (SEM), a technique that is specifically designed to reveal causal relationships between variables, and which also allows to include hypothetical causal factors. Therefore, SEM seems ideally suited for comparing alternative hypotheses on how fitness differences arise from differences in social and environmental factors. We apply SEM to a rich data set collected in a long-term study on the Seychelles warbler (Acrocephalus sechellensis), a bird species with facultatively cooperative breeding and a high rate of extra-group paternity. Our analysis reveals that the presence of helpers has a positive effect on the reproductive output of both female and male breeders. In contrast, per capita food availability does not affect reproductive output. Our analysis does not confirm earlier suggestions on other species that the presence of helpers has a negative effect on the reproductive output of male breeders. As such, both female and male breeders should tolerate helpers in their territories, irrespective of food availability

Structural equation modeling reveals determinants of fitness in a cooperatively breeding bird

Even in well-studied organisms, it is often challenging to uncover the social and environmental determinants of fitness. Typically, fitness is determined by a variety of factors that act in concert, thus forming complex networks of causal relationships. Moreover, even strong correlations between social and environmental conditions and fitness components may not be indicative of direct causal links, as the measured variables may be driven by unmeasured (or unmeasurable) causal factors. Standard statistical approaches, like multiple regression analyses, are not suited for disentangling such complex causal relationships. Here, we apply structural equation modeling (SEM), a technique that is specifically designed to reveal causal relationships between variables, and which also allows to include hypothetical causal factors. Therefore, SEM seems ideally suited for comparing alternative hypotheses on how fitness differences arise from differences in social and environmental factors. We apply SEM to a rich data set collected in a long-term study on the Seychelles warbler (Acrocephalus sechellensis), a bird species with facultatively cooperative breeding and a high rate of extra-group paternity. Our analysis reveals that the presence of helpers has a positive effect on the reproductive output of both female and male breeders. In contrast, per capita food availability does not affect reproductive output. Our analysis does not confirm earlier suggestions on other species that the presence of helpers has a negative effect on the reproductive output of male breeders. As such, both female and male breeders should tolerate helpers in their territories, irrespective of food availability

HI in the Outskirts of Nearby Galaxies

The HI in disk galaxies frequently extends beyond the optical image, and can trace the dark matter there. I briefly highlight the history of high spatial resolution HI imaging, the contribution it made to the dark matter problem, and the current tension between several dynamical methods to break the disk-halo degeneracy. I then turn to the flaring problem, which could in principle probe the shape of the dark halo. Instead, however, a lot of attention is now devoted to understanding the role of gas accretion via galactic fountains. The current $\rm \Lambda$ cold dark matter theory has problems on galactic scales, such as the core-cusp problem, which can be addressed with HI observations of dwarf galaxies. For a similar range in rotation velocities, galaxies of type Sd have thin disks, while those of type Im are much thicker. After a few comments on modified Newtonian dynamics and on irregular galaxies, I close with statistics on the HI extent of galaxies.Comment: 38 pages, 17 figures, invited review, book chapter in "Outskirts of Galaxies", Eds. J. H. Knapen, J. C. Lee and A. Gil de Paz, Astrophysics and Space Science Library, Springer, in pres

Measurement of the Charged Multiplicities in b, c and Light Quark Events from Z0 Decays

Average charged multiplicities have been measured separately in $b$, $c$ and light quark ($u,d,s$) events from $Z^0$ decays measured in the SLD experiment. Impact parameters of charged tracks were used to select enriched samples of $b$ and light quark events, and reconstructed charmed mesons were used to select $c$ quark events. We measured the charged multiplicities: $\bar{n}_{uds} = 20.21 \pm 0.10 (\rm{stat.})\pm 0.22(\rm{syst.})$, $\bar{n}_{c} = 21.28 \pm 0.46(\rm{stat.}) ^{+0.41}_{-0.36}(\rm{syst.})$ $\bar{n}_{b} = 23.14 \pm 0.10(\rm{stat.}) ^{+0.38}_{-0.37}(\rm{syst.})$, from which we derived the differences between the total average charged multiplicities of $c$ or $b$ quark events and light quark events: $\Delta \bar{n}_c = 1.07 \pm 0.47(\rm{stat.})^{+0.36}_{-0.30}(\rm{syst.})$ and $\Delta \bar{n}_b = 2.93 \pm 0.14(\rm{stat.})^{+0.30}_{-0.29}(\rm{syst.})$. We compared these measurements with those at lower center-of-mass energies and with perturbative QCD predictions. These combined results are in agreement with the QCD expectations and disfavor the hypothesis of flavor-independent fragmentation.Comment: 19 pages LaTex, 4 EPS figures, to appear in Physics Letters