Systematic Study of High p_T Hadron Spectra in pp, pA and AA Collisions from SPS to RHIC Energies

High-$p_T$ particle spectra in $p+p$ ($\bar p + p$), $p+A$ and $A+B$ collisions are calculated within a QCD parton model in which intrinsic transverse momentum, its broadening due to initial multiple parton scattering, and jet quenching due to parton energy loss inside a dense medium are included phenomenologically. The intrinsic $k_T$ and its broadening in $p+A$ and $A+B$ collisions due to initial multiple parton scattering are found to be very important at low energies ($\sqrt{s}<50$ GeV). Comparisons with $S+S$, $S+Au$ and $Pb+Pb$ data with different centrality cuts show that the differential cross sections of large transverse momentum pion production ($p_T>1$ GeV/$c$) in $A+B$ collisions scale very well with the number of binary nucleon-nucleon collisions (modulo effects of multiple initial scattering). This indicates that semi-hard parton scattering is the dominant particle production mechanism underlying the hadron spectra at moderate $p_T \stackrel{>}{\sim} 1$ GeV/$c$. However, there is no evidence of jet quenching or parton energy loss. Within the parton model, one can exclude an effective parton energy loss $dE_q/dx>0.01$ GeV/fm and a mean free path $\lambda_q< 7$ fm from the experimental data of $A+B$ collisions at the SPS energies. Predictions for high $p_T$ particle spectra in $p+A$ and $A+A$ collisions with and without jet quenching at the RHIC energy are also given. Uncertainties due to initial multiple scattering and nuclear shadowing of parton distributions are also discussed.Comment: 13 pages in RevTex with 14 figures, the final published version (with some typos corrected

The quality of research synthesis in surgery: the case of laparoscopic surgery for colorectal cancer

Peer reviewedPublisher PD

Assessment of microbial DNA extraction methods of cadaver soil samples for criminal investigations

<p>Gravesoil beneath decomposing cadavers undergoes substantial biochemical changes that have the potential to aid in PMI estimation and identification of clandestine gravesites. The use of DNA extraction methods is necessary for culture-independent downstream molecular applications such as PCR and next-generation sequencing. In this study, a comparison of four methods was performed for cadaver-soil collected beneath the heads and feet of 11 cadavers decaying in a natural setting. The four methods isolated 3.6–263 ng/μl of genomic DNA as determined by optical density analysis. The purity of the extracted DNA according to A_260/280 and A_260/230 ratios was determined. The A_260/280 and A_260/230 ratios were 1.24–1.97 and 0.27–2.12, respectively. The optical density at 320 nm was measured for humic acid quantification of the lysates from the method that provided the most efficient removal of humic acid. The results demonstrated that this method provided a 98% reduction of humic acid. PCR of 16S rRNA genes followed by gel electrophoresis was performed. The statistical analysis revealed a significant correlation between the yields and days on/in the soil using a phenol-chloroform method for soil collected at the head and feet. No earlier published work has extensively elucidated the efficacy of DNA extraction methods for DNA obtained from cadaver-soil.</p