Tides in colliding galaxies

Long tails and streams of stars are the most noticeable upshots of galaxy collisions. Their origin as gravitational, tidal, disturbances has however been recognized only less than fifty years ago and more than ten years after their first observations. This Review describes how the idea of galactic tides emerged, in particular thanks to the advances in numerical simulations, from the first ones that included tens of particles to the most sophisticated ones with tens of millions of them and state-of-the-art hydrodynamical prescriptions. Theoretical aspects pertaining to the formation of tidal tails are then presented. The third part of the review turns to observations and underlines the need for collecting deep multi-wavelength data to tackle the variety of physical processes exhibited by collisional debris. Tidal tails are not just stellar structures, but turn out to contain all the components usually found in galactic disks, in particular atomic / molecular gas and dust. They host star-forming complexes and are able to form star-clusters or even second-generation dwarf galaxies. The final part of the review discusses what tidal tails can tell us (or not) about the structure and content of present-day galaxies, including their dark components, and explains how tidal tails may be used to probe the past evolution of galaxies and their mass assembly history. On-going deep wide-field surveys disclose many new low-surface brightness structures in the nearby Universe, offering great opportunities for attempting galactic archeology with tidal tails.Comment: 46 pages, 13 figures, Review to be published in "Tidal effects in Astronomy and Astrophysics", Lecture Notes in Physics. Comments are most welcom

The Cholecystectomy As A Day Case (CAAD) Score: A Validated Score of Preoperative Predictors of Successful Day-Case Cholecystectomy Using the CholeS Data Set

Background Day-case surgery is associated with significant patient and cost benefits. However, only 43% of cholecystectomy patients are discharged home the same day. One hypothesis is day-case cholecystectomy rates, defined as patients discharged the same day as their operation, may be improved by better assessment of patients using standard preoperative variables. Methods Data were extracted from a prospectively collected data set of cholecystectomy patients from 166 UK and Irish hospitals (CholeS). Cholecystectomies performed as elective procedures were divided into main (75%) and validation (25%) data sets. Preoperative predictors were identified, and a risk score of failed day case was devised using multivariate logistic regression. Receiver operating curve analysis was used to validate the score in the validation data set. Results Of the 7426 elective cholecystectomies performed, 49% of these were discharged home the same day. Same-day discharge following cholecystectomy was less likely with older patients (OR 0.18, 95% CI 0.15–0.23), higher ASA scores (OR 0.19, 95% CI 0.15–0.23), complicated cholelithiasis (OR 0.38, 95% CI 0.31 to 0.48), male gender (OR 0.66, 95% CI 0.58–0.74), previous acute gallstone-related admissions (OR 0.54, 95% CI 0.48–0.60) and preoperative endoscopic intervention (OR 0.40, 95% CI 0.34–0.47). The CAAD score was developed using these variables. When applied to the validation subgroup, a CAAD score of ≤5 was associated with 80.8% successful day-case cholecystectomy compared with 19.2% associated with a CAAD score >5 (p < 0.001). Conclusions The CAAD score which utilises data readily available from clinic letters and electronic sources can predict same-day discharges following cholecystectomy

Reactions of the cis-diamminediaquaplatinum(II) cation with 2-aminomalonic acid and its homologues, aspartic and glutamic acids. Rearrangements of metastable complexes with carboxylate-bound ligands to N,O-chelates and formation of di- and trinuclear comp

Reactions of cis-Pt(NH 3) 2(H 2O) 2 2+ (1) with 2-aminomalonic acid (amalH 2), aspartic acid (aspH 2), and glutamic acid (gluH 2) have been studied by multinuclear ( 1H, 13C, 195Pt, 15N) NMR spectroscopy. With aspH 2 or gluH 2, 1 gives initially a complex in which the ligand is bound through only one carboxylate group, cis-Pt(NH 3) 2(LH 2-O)(H 2O) 2+. At p

Displacement of norbornadiene (NBD) from PtR2(NBD) (R = Me, CF3) by weak ligands

Norbornadiene (NBD) is more easily displaced from PtMe2 (NBD) by other ligands than is cyclooctadiene (COD) from PtMe2 (COD). cis-PtMe2L2 (L = py, 1 2tmen, 1 2en, NH3, DMSO) have been prepared in this way. cis-PtMe2py2 is very reactive toward oxidative addition. Pyridine can usually be removed from the platinum(IV) products using acid. NBD is even more readily displaced from Pt(CF3)2 (NBD), giving cis-Pt(CF3)2L2 (L = py, 1 2tmen, 1 2en, NH3, DMSO, NCR, DMF, CN-, I-, acac-). cis-Pt(CF3)2py2 with CF2I gives fac-Pt(CF3)3py2I

Determinations of the QCD strong coupling alphas and the scale lambdaQCD)

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Pretransplant helper T-lymphocyte determination in bone marrow donors: acute graft-versus-host disease prediction and relation with long-term survival

Helper T-lymphocyte precursor (HTLp) frequency from 19 allogeneic bone marrow donors was tested to detect weak antigenic differences with the recipient, and then compared to the outcome. HTLp frequency was estimated in limiting dilution cultures, and HLA-DR and CD 80 expression by stimulating cells was measured by flow cytometry. 12/19 patients experienced acute graft-versus-host disease (aGVHD) grade II–IV. A good correlation was found between high pretransplant HTLp frequency and grade II–IV aGVHD (median: 1/55848 PBMNC for II–IV GVHD versus 1/ 184346 for 0–I GVHD; P¼0·008). Sensitivity was 82%, specificity 63%, negative predictive value 71% and positive predictive value 75%. Long-term survivors also had a lower HTLp median frequency (1/143354) when compared with patients who died as a result of the transplant procedure (1/22100, P < 0·001). No correlation was found between HTLp frequency and HLA-DR or CD80 expression by patient’s cells. We conclude that HTLp frequency estimation can predict, although poorly, acute GVHD risk and long-term survival

Low mass photinos and supernova 1987a

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