524 research outputs found
Grothendieck ring of pretriangulated categories
We consider the abelian group generated by quasi-equivalence classes of
pretriangulated DG categories with relations coming from semi-orthogonal
decompositions of corresponding triangulated categories. We introduce an
operation of "multiplication" on the collection of DG categories
which makes this abelian group into a commutative ring. A few applications are
considered: representability of "standard" functors between derived categories
of coherent sheaves on smooth projective varieties and a construction of an
interesting motivic measure.Comment: 33 page
Do school crossing guards make crossing roads safer? A quasi-experimental study of pedestrian-motor vehicle collisions in Toronto, Canada
Dietary intake and risk of asthma in children and adults : protocol for a systematic review and meta-analysis
Background: Diet has been proposed to modulate the risk of asthma in children and adults. An increasing body of epidemiological studies have been published in the last year investigating the association between dietary intake and asthma. As part of the Evidence-Based Clinical Practice Guideline Task Force on 'Lifestyle Interventions in Allergy and Asthma' funded by the European Academy of Allergy and Clinical Immunology, we will use a systematic approach to review the evidence from published scientific literature on dietary intake and asthma in children and adults. Methods: This systematic review will be carried out following the PRISMA guidelines. The protocol has been published in PROSPERO (CRD42016036078). We will review the evidence from epidemiological studies in children (from the age of 2 years) and adults and dietary intake of foods and nutrients. Discussion: The findings from this review will be used as a reference to inform guideline recommendations.Peer reviewe
A systematic review of randomised controlled trials on the effectiveness of exercise programs on lumbo pelvic pain among postnatal women
Background: A substantial number of women tend to be affected by Lumbo Pelvic Pain (LPP) following child birth.
Physical exercise is indicated as a beneficial method to relieve LPP, but individual studies appear to suggest mixed
findings about its effectiveness. This systematic review aimed to synthesise evidence from randomised controlled trials on the effectiveness of exercise on LPP among postnatal women to inform policy, practice and future research.
Methods: A systematic review was conducted of all randomised controlled trials published between January 1990 and July 2014, identified through a comprehensive search of following databases: PubMed, PEDro, Embase, Cinahl, Medline, SPORTDiscus, Cochrane Pregnancy and Childbirth Groupâs Trials Register, and electronic libraries of authorsâinstitutions.
Randomised controlled trials were eligible for inclusion if the intervention comprised of postnatal exercise for women
with LPP onset during pregnancy or within 3 months after delivery and the outcome measures included changes in
LPP. Selected articles were assessed using the PEDro Scale for methodological quality and findings were synthesised narratively as meta-analysis was found to be inappropriate due to heterogeneity among included studies.
Results: Four randomised controlled trials were included, involving 251 postnatal women. Three trials were rated as
of âgoodâ methodological quality. All trials, except one, were at low risk of bias. The trials included physical exercise
programs with varying components, differing modes of delivery, follow up times and outcome measures. Intervention
in one trial, involving physical therapy with specific stabilising exercises, proved to be effective in reducing LPP
intensity. An improvement in gluteal pain on the right side was reported in another trial and a significant difference in
pain frequency in another.
Conclusion: Our review indicates that only few randomised controlled trials have evaluated the effectiveness of
exercise on LPP among postnatal women. There is also a great amount of variability across existing trials in the
components of exercise programs, modes of delivery, follow up times and outcome measures. While there is some
evidence to indicate the effectiveness of exercise for relieving LPP, further good quality trials are needed to ascertain
the most effective elements of postnatal exercise programs suited for LPP treatment
OGLE-2013-BLG-0102LA,B: Microlensing binary with components at star/brown-dwarf and brown-dwarf/planet boundaries
We present the analysis of the gravitational microlensing event
OGLE-2013-BLG-0102. The light curve of the event is characterized by a strong
short-term anomaly superposed on a smoothly varying lensing curve with a
moderate magnification . It is found that the event was
produced by a binary lens with a mass ratio between the components of and the anomaly was caused by the passage of the source trajectory over a
caustic located away from the barycenter of the binary. From the analysis of
the effects on the light curve due to the finite size of the source and the
parallactic motion of the Earth, the physical parameters of the lens system are
determined. The measured masses of the lens components are and , which correspond to
near the hydrogen-burning and deuterium-burning mass limits, respectively. The
distance to the lens is and the projected separation
between the lens components is .Comment: 6 figures, 2 tables, ApJ submitte
Antifungal activity of a novel chromene dimer
The activity on Aspergillus spp. growth and on ochratoxin A production of two novel chromene dimers (3) was evaluated. The results of the bioassays indicate that the chromene dimer 3a inhibited mycelia growth by approximately 50% (EC50) at 140.1 ÎŒmol Lâ1 for A. niger, 384.2 ÎŒmol Lâ1 for A. carbonarius, 69.1 ÎŒmol Lâ1 for A. alliaceus and 559.1 ÎŒmol Lâ1 for A. ochraceus. When applied at concentrations of 2 mmol Lâ1, 3a totally inhibited the growth of all Aspergillus spp. tested. Furthermore, ochratoxin A production by A. alliaceus was reduced by about 94% with a 200 ÎŒmol Lâ1 solution of this compound. A moderate inhibitory effect was observed for the analogous structure 3b on ochratoxin A production but not in mycelia growth. No inhibition was registered for compounds 2a and 2b, used as synthetic precursors of the dimeric species 3.Fundação para a CiĂȘncia e a Tecnologia (FCT) - SFRH/BD/
11228/2002
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