382 research outputs found
Energy-momentum Density of Gravitational Waves
In this paper, we elaborate the problem of energy-momentum in general
relativity by energy-momentum prescriptions theory. Our aim is to calculate
energy and momentum densities for the general form of gravitational waves. In
this connection, we have extended the previous works by using the prescriptions
of Bergmann and Tolman. It is shown that they are finite and reasonable. In
addition, using Tolman prescription, exactly, leads to same results that have
been obtained by Einstein and Papapetrou prescriptions.Comment: LaTeX, 9 pages, 1 table: added reference
Can an odd number of fermions be created due to chiral anomaly?
We describe a possibility of creation of an odd number of fractionally
charged fermions in 1+1 dimensional Abelian Higgs model. We point out that for
1+1 dimensions this process does not violate any symmetries of the theory, nor
makes it mathematically inconsistent. We construct the proper definition of the
fermionic determinant in this model and underline its non-trivial features that
are of importance for realistic 3+1 dimensional models with fermion number
violation.Comment: 12 pages revtex, 2 figure
Une tumeur maligne des gaines des nerfs périphériques compliquant la maladie de Von Recklinghausen
Les tumeurs malignes des gaines des nerfs périphériques ou MPNST (Malign Peripheral Nerve Sheath Tumors selon les anglo-saxons) sont des tumeurs rares qui constituent la principale complication des neurofibromatoses de type 1 (NF1) à l'ùge adulte. Du fait de leur rareté ces tumeurs posent à la fois des problÚmes diagnostiques et thérapeutiques. Nous rapportons une nouvelle observation de MPNST survenue chez une patiente suivie pour une NF1 et dont le traitement a consisté en une exérÚse large suivi d'une radiothérapie. Le but de ce travail est d'étudier les critÚres diagnostiques ainsi que la prise en charge thérapeutique de ce type de tumeurs
Mapping Local Cytosolic Enzymatic Activity in Human Esophageal Mucosa with Porous Silicon Nanoneedles
Porous silicon nanoneedles can map Cathepsin B activity across normal and tumor human esophageal mucosa. Assembling a peptideâbased Cathepsin B cleavable sensor over a large array of nanoÂneedles allows the discrimination of cancer cells from healthy ones in mixed culture. The same sensor applied to tissue can map Cathepsin B activity with high resolution across the tumor margin area of esophageal adenocarcinoma. [Image: see text
5-Cyano-1,3-phenylene diacetate
In the title molecule, C11H9NO4, the two acetoxy groups are twisted from the plane of the benzene ring by 67.89â
(4) and 53.30â
(5)°. Both carbonyl groups are on the same side of the aromatic ring. In the crystal, weak CâH...O hydrogen bonds link molecules into layers parallel to the ac plane. The crystal packing exhibits ÏâÏ interactions between the aromatic rings, indicated by a short intercentroid distance of 3.767â
(3)â
Ă
Surdité professionnelle dans une industrie automobile de la région du centre Tunisien reconnaissance et indemnisation
Objectif : La surditĂ© professionnelle pose encore des problĂšmes de reconnaissance et dâindemnisation en Tunisie. Lâobjectif de notre Ă©tude est dâanalyser les conditions de reconnaissance et dâindemnisation de la surditĂ© professionnelle auprĂšs des travailleurs dâune industrie automobile.MatĂ©riel et mĂ©thodes : Nous avons menĂ© une Ă©tude descriptive rĂ©trospective qui a portĂ© sur les salariĂ©s de la SociĂ©tĂ© Tunisienne dâIndustrie Automobile (STIA) victimes de surditĂ© professionnelle reconnue par la Commission MĂ©dicale du centre sur une pĂ©riode de cinq ans (2003 Ă 2007).RĂ©sultats : Un total de 81 dossiers de surditĂ© professionnelle reconnue a Ă©tĂ© colligĂ© durant la pĂ©riode dâĂ©tude. Notre population Ă©tait constituĂ©e par une main dâoeuvre masculine qualifiĂ©e (50,6%) et non qualifiĂ©e (38,3%) ayant une anciennetĂ© moyenne dans le poste bruyant de 28,7 ± 6,8 ans. Le niveau moyen dâexposition professionnelle au bruit Ă©tait de 90,7 ± 3,9dB(A). Il Ă©tait plus Ă©levĂ© dans les ateliers de presse [92,4dB(A)], de tĂŽlerie [91,6 dB(A)] et de peinture [90 dB(A)]. La perte auditive moyenne (PAM) sur la meilleure oreille Ă©tait de 65,7 ± 17,4dB. Les potentiels Ă©voquĂ©s auditifs ont Ă©tĂ© pratiquĂ©s chez 66 patients (81,5%) et ont confirmĂ© le diagnostic de surditĂ© de perception dans 64 cas et dâune surditĂ© mixte dans les 2 autres cas. LâaudiomĂ©trie tonale avec prothĂšse auditive a Ă©tĂ© pratiquĂ©e dans 71,6% des cas et a relevĂ© une amĂ©lioration estimĂ©e nette chez 81% des patients. Le taux moyen de lâincapacitĂ©permanente partielle Ă©tait de 21,5 ± 6,8% avec des extrĂȘmes allant de 8 et 51%. La majoritĂ© des salariĂ©s (92,6%) avaient un taux dâIPP entre 15 et 35%. La PAM > 60 dB a Ă©tĂ© statistiquement corrĂ©lĂ©e avec la catĂ©gorie professionnelle (p=0,017) et lâanciennetĂ© au travail (p=0,039).Conclusion : La rĂ©paration de la surditĂ© professionnelle prĂ©sente encore des limites et des imperfections liĂ©es aux critĂšres de reconnaissances qui doivent ĂȘtre rĂ©visĂ©es.Mots-clĂ©s : SurditĂ© professionnelle, Bruit, Industrie automobile, RĂ©paration
Fundoplication to preserve allograft function after lung transplant: Systematic review and meta-analysis
Background:
ARS has been adopted in select patients with lung transplant for the past 2 decades inmany centers. Outcomes have been reported sporadically. No pooled analysis of retrospective series has been performed.
Objective:
This review and pooled analysis sought to demonstrate objective evidence of improved graft function in lung transplant patients undergoing antireflux surgery (ARS).
Methods:
In accordance with Meta-analyses of Observational Studies in Epidemiology guidelines, a search of PubMed Central, Medline, Google Scholar, and Cochrane Library databases was performed. Articles documenting spirometry data pre- and post-ARS were reviewed and a random-effects model meta-analysis was performed on forced expiratory volume in 1 second (FEV1) values and the rate of change of FEV1.
Results:
Six articles were included in the meta-analysis. Regarding FEV1 before and after ARS, we observed a small increase in FEV1 values in studies reporting raw values (2.02 ± 0.89 L/1 sec vs 2.14 ± 0.77 L/1 sec; n = 154) and % of predicted (77.1% ± 22.1% vs 81.2% ± 26.95%; n = 45), with a small pooled Cohen d effect size of 0.159 (P = .114). When considering the rate of change of FEV1 we observed a significant difference in pre-ARS compared with post-ARS (â2.12 ± 2.76 mL/day vs +0.05 ± 1.19 mL/day; n = 103). There was a pooled effect size of 1.702 (P = .013), a large effect of ARS on the rate of change of FEV1 values.
Conclusions:
This meta-analysis of retrospective observational studies demonstrates that ARS might benefit patients with declining FEV1, by examining the rate of change of FEV1 during the pre- and postoperative periods
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