947 research outputs found
Poly(Ethylene Terephthalate), PET. A Review on the Synthesis Processes, Degradation Mechanisms and its Recycling
We present a review on poly(ethylene terephthalate), emphasizing the synthesis processes and the degradation Mechanisms. Brazil is currently among the countries that most recycle PET, with 53% of this polymer being mechanically recycled. The success of this thermoplastic in the recycling industry is due to its large diversity of applications, from the textile industry to food packaging, where the food grade recycled packages will be mixed with the pristine resin for reprocessing and use. We also discuss the present legal aspects concerning PET recycling and its use it) contact with food. In the synthesis of PET, usually done in two or three steps, several co-monomers and additives are used to optimize the final properties and processing conditions. Additionally, during the synthesis, processing and recycling, several degradation (thermomechanical and thermo-oxidation) and secondary reactions occur, producing acetaldehydes, oligomers and diethyleneglicol. The presence of these 'contaminants' accelerates the degradation process of the polymer affecting the final product characteristics.19212113
Behavioural differences between weaner pigs with intact and docked tails
AbstractTail-biting in pigs (Sus scrofa) reduces welfare and production. Tail-docking reduces (but does not eliminate) tail-biting damage. The reason tail-docking reduces tail damage is unknown. It may reduce pigs’ attraction to tails (H1), or increase tails’ sensitivity to investigation (H2). To investigate these hypotheses, behavioural differences between 472 individually marked grower pigs with intact tails (nine groups of 25-34 pigs) or docked tails (nine groups of 22-24 pigs) were observed from 5-8 weeks of age on a commercial farm in Denmark. Pens had part-slatted floors, dry feeding and two handfuls of straw per day, and enrichment objects were provided. Behavioural sampling recorded actor and recipient for tail-directed (tail interest, tail in mouth, tail reaction) and investigatory behaviours (belly-nosing, ear-chewing, interaction with enrichment). Scan sampling recorded pig posture/activity and tail posture. Intact-tail pigs performed more overall investigatory behaviours but tail type did not affect the amount of tail-directed behaviours. Larger pigs performed more investigatory and tail-directed behaviours than smaller pigs and females performed slightly more tail investigation. Tail-directed behaviours were not consistent over time at the individual or group level. However, ear-chewing was consistent at the group level. One group with intact tails was affected by a tail-biting outbreak in the final week of the study (evidenced by tail-damage scores) and showed an increase over time in tail posture (tail down) and tail-directed behaviour but not activity. Overall, there were few behavioural differences between docked and undocked pigs: no evidence of reduced tail investigation (H1) or an increased reaction to tail investigation (H2) in docked pigs, and yet docked pigs had less tail damage. We propose that docking might be effective because longer tails are more easily damaged as pigs are able to bite them with their cheek teeth.</jats:p
Effects of pilates exercise programs in people with chronic low back pain: a systematic review
The Pilates method has recently become a fast-growing popular way of exercise recommended for healthy individuals and those engaged in rehabilitation. Several published studies have examined the effects of Pilates method in people with chronic low back pain (LBP).The objective of this study is to describe and provide an extensive overview of the scientific literature comparing the effectiveness of the Pilates method on pain and disability in patients with chronic nonspecific LBP. The study is based on the data from the following sources: MEDLINE-NLM, MEDLINE-EBSCO, Scopus Elsevier, Cochrane, DOAJ, SciELO, and PLOSONE.Original articles and systematic reviews of adults with chronic nonspecific LBP that evaluated pain and/or disability were included in this study; studies in which the primary treatment was based on Pilates method exercises compared with no treatment, minimal intervention, other types of intervention, or other types of exercises.The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were adopted. The literature search included 7 electronic databases and the reference list of relevant systematic reviews and original articles to July 2014. Two independent investigators conducted the literature search and performed the synthesis as follows: Study Design; Sample (n); Disability measure; Intervention; and Main results.The searches identified a total of 128 articles. From these, 29 were considered eligible and were included in the analysis. The items were stratified as follows: Pilates method versus other kind of exercises (n = 6 trials) and Pilates method versus no treatment group or minimal intervention for short-term pain (n = 9 trials); the therapeutic effect of the Pilates method in randomized cohorts (n = 5); and analysis of reviews (n = 9).We found that there is a dearth of studies that clearly demonstrates the efficacy of a specific Pilates exercise program over another in the treatment of chronic pain. However, the consensus in the field suggests that Pilates method is more effective than minimal physical exercise intervention in reducing pain. These conclusions need to be supported by other proper investigations
Skin cancer screening participation and impact on melanoma incidence in Germany – an observational study on incidence trends in regions with and without population-based screening
Background: The SCREEN (Skin Cancer Research to provide Evidence for Effectiveness of Screening in Northern Germany) project involved population-wide skin cancer screening with whole-body examination by general physicians and dermatologists. It was conducted in the German state of Schleswig-Holstein (July 2003–June 2004), but not in the German state of Saarland. Methods: The population-based registries of Schleswig-Holstein and Saarland provided data on melanoma incidence before, during, and after SCREEN to assess the association of skin cancer screening with incidence. Results: Approximately 19% of the Schleswig-Holstein population participated in SCREEN (women: 27%, men: 10%). A total of 52% of all melanomas diagnosed during SCREEN in Schleswig-Holstein were detected as part of the project. Melanoma incidence increased during SCREEN (invasive melanoma in women: +8.9 per 100 000 (95% confidence intervals (CI): 6.1; 11.7); men: +4.0 per 100 000 (95% CI: 1.6; 6.4)) and decreased afterwards (women: −10.6 per 100 000 (95% CI: −13.3; −7.9); men: −4.1 per 100 000 (95% CI: −6.5; −1.7)). Similar changes were not observed in Saarland that had no such project. The differences between the two states were greatest among women, the group with the greater SCREEN participation. Conclusion: The SCREEN project had a substantial impact on melanoma incidence. This is consistent with the impact of effective screening for other cancers
Social Class
Discussion of class structure in fifth-century Athens, historical constitution of theater audiences, and the changes in the comic representation of class antagonism from Aristophanes to Menander
Electrosynthesis and optical characterization of poly(p-phenylene), polypyrrole and poly(p-phenylene)-polypyrrole films
Precision measurement of the top quark mass from dilepton events at CDF II
We report a measurement of the top quark mass, M_t, in the dilepton decay
channel of
using an integrated luminosity of 1.0 fb^{-1} of p\bar{p} collisions collected
with the CDF II detector. We apply a method that convolutes a leading-order
matrix element with detector resolution functions to form event-by-event
likelihoods; we have enhanced the leading-order description to describe the
effects of initial-state radiation. The joint likelihood is the product of the
likelihoods from 78 candidate events in this sample, which yields a measurement
of M_{t} = 164.5 \pm 3.9(\textrm{stat.}) \pm 3.9(\textrm{syst.})
\mathrm{GeV}/c^2, the most precise measurement of M_t in the dilepton channel.Comment: 7 pages, 2 figures, version includes changes made prior to
publication by journa
Measurement of the Ratios of Branching Fractions B(Bs -> Ds pi pi pi) / B(Bd -> Dd pi pi pi) and B(Bs -> Ds pi) / B(Bd -> Dd pi)
Using 355 pb^-1 of data collected by the CDF II detector in \ppbar collisions
at sqrt{s} = 1.96 TeV at the Fermilab Tevatron, we study the fully
reconstructed hadronic decays B -> D pi and B -> D pi pi pi. We present the
first measurement of the ratio of branching fractions B(Bs -> Ds pi pi pi) /
B(Bd -> Dd pi pi pi) = 1.05 pm 0.10 (stat) pm 0.22 (syst). We also update our
measurement of B(Bs -> Ds pi) / B(Bd -> Dd pi) to 1.13 pm 0.08 (stat) pm 0.23
(syst) improving the statistical uncertainty by more than a factor of two. We
find B(Bs -> Ds pi) = [3.8 pm 0.3 (stat) pm 1.3 (syst)] \times 10^{-3} and B(Bs
-> Ds pi pi pi) = [8.4 pm 0.8 (stat) pm 3.2 (syst)] \times 10^{-3}.Comment: 7 pages, 2 figure
Cross Section Measurements of High- Dilepton Final-State Processes Using a Global Fitting Method
We present a new method for studying high- dilepton events
(, , ) and simultaneously
extracting the production cross sections of , , and p\bar{p} \to \ztt at a center-of-mass energy of TeV. We perform a likelihood fit to the dilepton data in a parameter
space defined by the missing transverse energy and the number of jets in the
event. Our results, which use of data recorded with the CDF
II detector at the Fermilab Tevatron Collider, are pb, pb, and
\sigma(\ztt) =291^{+50}_{-46} pb.Comment: 20 pages, 2 figures, to be submitted to PRD-R
Top Quark Mass Measurement from Dilepton Events at CDF II with the Matrix-Element Method
We describe a measurement of the top quark mass using events with two charged
leptons collected by the CDF II detector from collisions with TeV at the Fermilab Tevatron. The likelihood in top mass is
calculated for each event by convoluting the leading order matrix element
describing
with detector resolution functions. The presence of background events in the
data sample is modeled using similar calculations involving the matrix elements
for major background processes. In a data sample with integrated luminosity of
340 pb, we observe 33 candidate events and measure This
measurement represents the first application of this method to events with two
charged leptons and is the most precise single measurement of the top quark
mass in this channel.Comment: 21 pages, 14 figure
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