Safety of overlapping inpatient orthopaedic surgery: A multicenter study

BackgroundAlthough overlapping surgery is used to maximize efficiency, more empirical data are needed to guide patient safety. We conducted a retrospective cohort study to evaluate the safety of overlapping inpatient orthopaedic surgery, as judged by the occurrence of perioperative complications.MethodsAll inpatient orthopaedic surgical procedures performed at 5 academic institutions from January 1, 2015, to December 31, 2015, were included. Overlapping surgery was defined as 2 skin incisions open simultaneously for 1 surgeon. In comparing patients who underwent overlapping surgery with those who underwent non-overlapping surgery, the primary outcome was the occurrence of a perioperative complication within 30 days of the surgical procedure, and secondary outcomes included all-cause 30-day readmission, length of stay, and mortality. To determine if there was an association between overlapping surgery and a perioperative complication, we tested for non-inferiority of overlapping surgery, assuming a null hypothesis of an increased risk of 50%. We used an inverse probability of treatment weighted regression model adjusted for institution, procedure type, demographic characteristics (age, sex, race, comorbidities), admission type, admission severity of illness, and clustering by surgeon.ResultsAmong 14,135 cases, the frequency of overlapping surgery was 40%. The frequencies of perioperative complications were 1% in the overlapping surgery group and 2% in the non-overlapping surgery group. The overlapping surgery group was non-inferior to the non-overlapping surgery group (odds ratio [OR], 0.61 [90% confidence interval (CI), 0.45 to 0.83]; p < 0.001), with reduced odds of perioperative complications (OR, 0.61 [95% CI, 0.43 to 0.88]; p = 0.009). For secondary outcomes, there was a significantly lower chance of all-cause 30-day readmission in the overlapping surgery group (OR, 0.67 [95% CI, 0.52 to 0.87]; p = 0.003) and shorter length of stay (e, 0.94 [95% CI, 0.89 to 0.99]; p = 0.012). There was no difference in mortality.ConclusionsOur results suggest that overlapping inpatient orthopaedic surgery does not introduce additional perioperative risk for the complications that we evaluated. The suitability of this practice should be determined by individual surgeons on a case-by-case basis with appropriate informed consent.Level of evidenceTherapeutic Level III. See Instructions for Authors for a complete description of levels of evidence

Renaissance of the ~1 TeV Fixed-Target Program

This document describes the physics potential of a new fixed-target program based on a ~1 TeV proton source. Two proton sources are potentially available in the future: the existing Tevatron at Fermilab, which can provide 800 GeV protons for fixed-target physics, and a possible upgrade to the SPS at CERN, called SPS+, which would produce 1 TeV protons on target. In this paper we use an example Tevatron fixed-target program to illustrate the high discovery potential possible in the charm and neutrino sectors. We highlight examples which are either unique to the program or difficult to accomplish at other venues.Comment: 31 pages, 11 figure

Agrobacterium tumefaciens-mediated transformation of Trichoderma harzianum CFAM-422 using an herbicide resistance gene as selection marker.

The use of lignocellulosic materials that are the constituents of the plant cell wall have shown to be a great opportunity for sustainable industrial development. The polysaccharide part of these materials, the cellulose and the hemicellulose, can be degraded into their monomeric sugars by microorganisms, such as Trichoderma harzianum, that secrete extracellular enzymes. However, the industrial production of hydrolytic enzymes rely on the development of molecular biology tools to achieve the economical production of enzyme pools with greater hydrolytic potential. In this work the fungus T. harzianum (CFAM-422) was transformed by Agrobacterium tumefaciens and a herbicide was used as a selective agent, making it an efficient strategy to obtain strains with higher potential for the hydrolysis of lignocellulosic materials.SINAFERM; SHEB. 3 a 6 de setembro. Seção Trabalhos. Ref. 59006

Leptoproduction of Heavy Quarks II -- A Unified QCD Formulation of Charged and Neutral Current Processes from Fixed-target to Collider Energies

A unified QCD formulation of leptoproduction of massive quarks in charged current and neutral current processes is described. This involves adopting consistent factorization and renormalization schemes which encompass both vector-boson-gluon-fusion (flavor creation) and vector-boson-massive-quark-scattering (flavor excitation) production mechanisms. It provides a framework which is valid from the threshold for producing the massive quark (where gluon-fusion is dominant) to the very high energy regime when the typical energy scale \mu is much larger than the quark mass m_Q (where the quark-scattering should be prevalent). This approach effectively resums all large logarithms of the type (alpha_s(mu) log(mu^2/m_Q^2)^n which limit the validity of existing fixed-order calculations to the region mu ~ O(m_Q). We show that the (massive) quark-scattering contribution (after subtraction of overlaps) is important in most parts of the (x, Q) plane except near the threshold region. We demonstrate that the factorization scale dependence of the structure functions calculated in this approach is substantially less than those obtained in the fixed-order calculations, as one would expect from a more consistent formulation.Comment: LaTeX format, 29 pages, 11 figures. Revised to make auto-TeX-abl

Virtual Photon Strucutre Functions and the Parton Content of the Electron

We point out that in processes involving the parton content of the photon the usual effective photon approximation should be modified. The reason is that the parton content of virtual photons is logarithmically suppressed compared to real photons. We describe this suppression using several simple, physically motivated ans\"atze. Although the parton content of the electron in general no longer factorizes into an electron flux function and a photon structure function, it can still be expressed as a single integral. Numerical examples are given for the \eplem\ collider TRISTAN as well as the $ep$ collider HERA.Comment: 16 pages and 3 figures (available from DREES@WSICPHEN as topdraw or PS files); LaTeX with equation.sty; MAD/PH/819, BU 94-0

Single-Top-Quark Production via W-Gluon Fusion at Next-to-Leading Order

Single-top-quark production via W-gluon fusion at hadron colliders provides an opportunity to directly probe the charged-current interaction of the top quark. We calculate the next-to-leading-order corrections to this process at the Fermilab Tevatron, the CERN Large Hadron Collider, and DESY HERA. Using a b-quark distribution function to sum collinear logarithms, we show that there are two independent corrections, of order 1/[ln(m_t^2/m_b^2)] and alpha_s. This observation is generic to processes involving a perturbatively derived heavy-quark distribution function at an energy scale large compared with the heavy-quark mass.Comment: 19 pages, 9 figures, small update to Phys. Rev. D versio

The Analysis of Multijet Events Produced at High Energy Hadron Colliders

We define and discuss a set of (4N - 4) parameters that can be used to analyse events in which N jets have been produced in high energy hadron-hadron collisions. These multijet variables are the multijet mass and (4N - 5) independent dimensionless parameters. To illustrate the use of the variables QCD predictions are presented for events with up to five jets produced at the Fermilab Tevatron Proton-Antiproton Collider. These QCD predictions are compared with the predictions of a model in which multijet events uniformly populate the N-body phase-space

Atomic structure of dislocation kinks in silicon

We investigate the physics of the core reconstruction and associated structural excitations (reconstruction defects and kinks) of dislocations in silicon, using a linear-scaling density-matrix technique. The two predominant dislocations (the 90-degree and 30-degree partials) are examined, focusing for the 90-degree case on the single-period core reconstruction. In both cases, we observe strongly reconstructed bonds at the dislocation cores, as suggested in previous studies. As a consequence, relatively low formation energies and high migration barriers are generally associated with reconstructed (dangling-bond-free) kinks. Complexes formed of a kink plus a reconstruction defect are found to be strongly bound in the 30-degree partial, while the opposite is true in the case of 90-degree partial, where such complexes are found to be only marginally stable at zero temperature with very low dissociation barriers. For the 30-degree partial, our calculated formation energies and migration barriers of kinks are seen to compare favorably with experiment. Our results for the kink energies on the 90-degree partial are consistent with a recently proposed alternative double-period structure for the core of this dislocation.Comment: 12 pages, two-column style with 8 postscript figures embedded. Uses REVTEX and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/index.html#rn_di