2,067 research outputs found
WZW-like Action for Heterotic String Field Theory
We complete the construction of the Neveu-Schwarz sector of heterotic string
field theory begun in hep-th/0406212 by giving a closed-form expression for the
action and gauge transformations. Just as the Wess-Zumino-Witten (WZW) action
for open superstring field theory can be constructed from pure-gauge fields in
bosonic open string field theory, our heterotic string field theory action is
constructed from pure-gauge fields in bosonic closed string field theory. The
construction involves a simple alternative form of the WZW action which is
consistent with the algebraic structures of closed string field theory.Comment: 22 pages, no figures, LaTeX2
Nematoda - free living
The list was compiled by Guy De Smet, a non-specialist, who was assisted by nematologists Magda Vincx, Ann Vanreusel, Sandra Vanhove, Jan Vanaverbeke and Maaike Steyaert. Dr. F. Riemann gave useful advice for the genus Daptonema. The classification in the list is based upon Lorenzen (1979, 1994). Information on the geographic distribution in the list is based upon Gerlach and Riemann (1973, 1974), Platt and Warwick (1983, 1988) and Warwick et al. (1998).ReferencesLorenzen, S. Entwürf eines Phylogenetischen Systems der Freilebenden Nematoden, Kiel, 1979.Lorenzen, S. The Phylogenetic Systematics of Freeliving Nematodes, The Ray Society, 1994.Gerlach, S. A. and Riemann, F. The Bremerhaven Checklist of Aquatic Nematodes. Veröffentlichungen des Instituts für Meeresforschung in Bremerhaven, Supplement 4, (Heft 1 1973, Heft 2 1974).Platt, H. M. and Warwick, R. M. Free-living Marine Nematodes (Part I British Enoplids) Synopses of the British Fauna (New series) No. 28, 1983.Platt, H. M. and Warwick, R. M. Free-living Marine Nematodes (Part II British Chromadorids) Synopses of the British Fauna (New series) No. 38, 1988.Warwick, R. M., Platt, H. M. and Somerfield, P. J. Free-living Marine Nematodes (Part III Monhysterids) Synopses of the British Fauna (New series) No. 53, 1998.</ul
Spinor classification of the Weyl tensor in five dimensions
We investigate the spinor classification of the Weyl tensor in five
dimensions due to De Smet. We show that a previously overlooked reality
condition reduces the number of possible types in the classification. We
classify all vacuum solutions belonging to the most special algebraic type. The
connection between this spinor and the tensor classification due to Coley,
Milson, Pravda and Pravdov\'a is investigated and the relation between most of
the types in each of the classifications is given. We show that the black ring
is algebraically general in the spinor classification.Comment: 40 page
Rolling Closed String Tachyons and the Big Crunch
We study the low-energy effective field equations that couple gravity, the
dilaton, and the bulk closed string tachyon of bosonic closed string theory. We
establish that whenever the tachyon induces the rolling process, the string
metric remains fixed while the dilaton rolls to strong coupling. For negative
definite potentials we show that this results in an Einstein metric that
crunches the universe in finite time. This behavior is shown to be rather
generic even if the potentials are not negative definite. The solutions are
reminiscent of those in the collapse stage of a cyclic universe cosmology where
scalar field potentials with negative energies play a central role.Comment: 13 pages, 2 figures, LaTeX. Replaced version: one reference adde
The Kerr-Newman-Godel Black Hole
By applying a set of Hassan-Sen transformations and string dualities to the
Kerr-Godel solution of minimal D=5 supergravity we derive a four parameter
family of five dimensional solutions in type II string theory. They describe
rotating, charged black holes in a rotating background. For zero background
rotation, the solution is D=5 Kerr-Newman; for zero charge it is Kerr-Godel. In
a particular extremal limit the solution describes an asymptotically Godel BMPV
black hole.Comment: 12 pages, LaTeX, no figures; v2: one reference added, very minor
changes; to appear in CQ
Selective digestive and oropharyngeal decontamination in medical and surgical ICU patients:individual patient data meta-analysis
Objectives: Selective digestive decontamination (SDD) and selective oropharyngeal decontamination (SOD) improved intensive care unit (ICU), hospital and 28-day survival in ICUs with low levels of antibiotic resistance. Yet it is unclear whether the effect differs between medical and surgical ICU patients.& para;& para;Methods: In an individual patient data meta-analysis, we systematically searched PubMed and included all randomized controlled studies published since 2000. We performed a two-stage meta-analysis with separate logistic regression models per study and per outcome (hospital survival and ICU survival) and subsequent pooling of main and interaction effects.& para;& para;Results: Six studies, all performed in countries with low levels of antibiotic resistance, yielded 16 528 hospital admissions and 17 884 ICU admissions for complete case analysis. Compared to standard care or placebo, the pooled adjusted odds ratios for hospital mortality was 0.82 (95% confidence interval (CI) 0.72-0.93) for SDD and 0.84 (95% CI 0.73-0.97) for SOD. Compared to SOD, the adjusted odds ratio for hospital mortality was 0.90 (95% CI 0.82-0.97) for SDD. The effects on hospital mortality were not modified by type of ICU admission (p values for interaction terms were 0.66 for SDD and control, 0.87 for SOD and control and 0.47 for SDD and SOD). Similar results were found for ICU mortality.& para;& para;Conclusions: In ICUs with low levels of antibiotic resistance, the effectiveness of SDD and SOD was not modified by type of ICU admission. SDD and SOD improved hospital and ICU survival compared to standard care in both patient populations, with SDD being more effective than SOD. (C) 2017 The Author(s). Published by Elsevier Ltd on behalf of European Society of Clinical Microbiology and Infectious Diseases
Answer to the comment of Dr. Petros et al. on our manuscript about accumulation of oral antibiotics as an adverse effect of selective decontamination of the digestive tract
Становлення та функціонування сучасних наукових шкіл
Background. Several studies have shown that the use of selective digestive tract decontamination (SDD) reduces mortality. However, fear for increasing multidrug resistance might prevent wide acceptance. A survey was performed among the units registered in the European Registry for Intensive Care (ERIC), in order to investigate the number of ICUs using SDD and the factors that prevented the use of SDD. Methods. One invitation to the electronic survey was sent to each ERIC unit. The survey focused on department characteristics (intensive care type, local resistance levels), local treatment modalities (antibiotic stewardship) and doctors' opinions (collaborative issues concerning SDD). All ICU's in countries participating in the European Centre for Disease Prevention and Control resistance surveillance program were analysed. Results. Seventeen percent of the ICUs registered in the ERIC database used SDD prophylaxis. Most of these ICUs were located in the Netherlands or Germany. ICUs using SDD were four times more likely to use antibiotic stewardship. Also larger ICUs were more likely to use SDD. On the contrary, resistance to antibiotics was not related to the use of SDD. Also the doctor's opinion that SDD is proven in duster-randomized trials was not a determinant for not using SDD. Conclusion. SDD is used in a minority of the European ICUs registered in the ERIC database. Larger ICUs and ICUs with a prudent antibiotic policy were more likely to use SDD. Neither antibiotic resistance nor the duster randomized study design were determinants of the non-use of SDD
Cosmological tachyon from cubic string field theory
The classical dynamics of the tachyon scalar field of cubic string field
theory is considered on a cosmological background. Starting from a nonlocal
action with arbitrary tachyon potential, which encodes the bosonic and several
supersymmetric cases, we study the equations of motion in the Hamilton-Jacobi
formalism and with a generalized Friedmann equation, appliable in braneworld or
modified gravity models. The cases of cubic (bosonic) and quartic
(supersymmetric) tachyon potential in general relativity are automatically
included. We comment the validity of the slow-roll approximation, the stability
of the cosmological perturbations, and the relation between this tachyon and
the Dirac-Born-Infeld one.Comment: 20 pages JHEP style, 1 figure; v4: misprints corrected, matches the
published versio
Tachyon Couplings to Fermion
By fixing the internal CP factor of tachyon and massless Ramond vertex
operators in different pictures, we have shown that the internal CP factor of
the disk level S-matrix elements of two fermions and odd number of tachyon
vertex operators in the world volume of non-BPS D-branes/D-brane-anti-D-brane
is zero. We have calculated the S-matrix element of two fermions and two
tachyons which has non vanishing internal CP factor, and found the momentum
expansion of this amplitude. In the abelian case, we have compared the
two-fermion-two-tachyon coupling at low energy with the corresponding coupling
in the gauge-fixed supersymmetric tachyon DBI action. The couplings in the two
cases are exactly the same.Comment: 16 pages, latex file; V2:a missing term in the modified tachyon DBI
action adde
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