Isolated tau leptons in events with large missing transverse momentum at HERA

A search for events containing isolated tau leptons and large missing transverse momentum, not originating from the tau decay, has been performed with the ZEUS detector at the electron-proton collider HERA, using 130 pb^-1 of integrated luminosity. A search was made for isolated tracks coming from hadronic tau decays. Observables based on the internal jet structure were exploited to discriminate between tau decays and quark- or gluon-induced jets. Three tau candidates were found, while 0.40 +0.12 -0.13 were expected from Standard Model processes, such as charged current deep inelastic scattering and single W-boson production. To search for heavy-particle decays, a more restrictive selection was applied to isolate tau leptons produced together with a hadronic final state with high transverse momentum. Two candidate events survive, while 0.20 +-0.05 events are expected from Standard Model processes.Comment: 28 pages, 4 figures, 3 tables, accepted by Phys. Lett. B. Updated with minor changes to the text requested by the journal refere

Observation of Scaling Violations in Scaled Momentum Distributions at HERA

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.Comment: 21 pages including 4 figures, to be published in Physics Letters B. Two references adde

On the Job: Dr. Karen Chojnacki, Residency Program Director

Karen Chojnacki, MD, FACS, who has directed the General Surgery Residency Program for the past three years, was a resident at Jefferson from 1995 to 2000 – and loved it. Following a fellowship in minimally invasive surgery at the University of Southern California and a brief stint in private practice, she returned to Jefferson in early 2002, jumping at the chance to capture her “dream job” and buoyed by memories of the institution’s camaraderie and professionalism. “Whoever said ‘You can’t go home again’ didn’t have a home like Jefferson,” she says. “I lead the program that helped make me the physician I am today, and now it’s my turn to give back and help residents develop the careers they want.” During Dr. Chojnacki’s tenure the program has undergone several changes. Prior to the start of the program, incoming interns must complete the web-based American College of Surgeons (ACS) Fundamentals of Surgery Curriculum™ which guides them through common surgical problems. A formal program in bedside procedure training was initiated to train all PGY-1 (first post-graduate year) residents in procedures including central line placement, bronchoscopy, suturing, and foley catheter placement, through lectures and virtual practice in the Laparoscopic and Simulation Training Laboratory. Upon completion of this course, they must be supervised through and attain passing evaluations for a number of these procedures before performing them independently. The overall curriculum has changed to follow the SCORE (Surgical Council on Resident Education) curriculum, a competency based standard national curriculum created by a task force of the ACS and the American Board of Surgery (ABS). These changes are paying off. “We have one of the best residency programs in the region,” said Dr. Chojnacki, “and since we emphasize research, over 90 percent of our residents secure the fellowships of their choice.

Human haematopoietic stem cells express Oct4 pseudogenes and lack the ability to initiate Oct4 promoter-driven gene expression

The transcription factor Oct4 is well defined as a key regulator of embryonic stem (ES) cell pluripotency. In recent years, the role of Oct4 has purportedly extended to the self renewal and maintenance of multipotency in adult stem cell (ASC) populations. This profile has arisen mainly from reports utilising reverse transcription-polymerase chain reaction (RT-PCR) based methodologies and has since come under scrutiny following the discovery that many developmental genes have multiple pseudogenes associated with them. Six known pseudogenes exist for Oct4, all of which exhibit very high sequence homology (three >97%), and for this reason the generation of artefacts may have contributed to false identification of Oct4 in somatic cell populations. While ASC lack a molecular blueprint of transcription factors proposed to be involved with 'stemness' as described for ES cells, it is not unreasonable to assume that similar gene patterns may exist. The focus of this work was to corroborate reports that Oct4 is involved in the regulation of ASC self-renewal and differentiation, using a combination of methodologies to rule out pseudogene interference. Haematopoietic stem cells (HSC) derived from human umbilical cord blood (UCB) and various differentiated cell lines underwent RT-PCR, product sequencing and transfection studies using an Oct4 promoter-driven reporter. In summary, only the positive control expressed Oct4, with all other cell types expressing a variety of Oct4 pseudogenes. Somatic cells were incapable of utilising an exogenous Oct4 promoter construct, leading to the conclusion that Oct4 does not appear involved in the multipotency of human HSC from UCB

Characteristics of Stem Cells Derived from the Degenerated Human Intervertebral Disc Cartilage Endplate

Mesenchymal stem cells (MSCs) derived from adult tissues are an important candidate for cell-based therapies and regenerative medicine due to their multipotential differentiation capability. MSCs have been identified in many adult tissues but have not reported in the human intervertebral disc cartilage endplate (CEP). The initial purpose of this study was to determine whether MSCs exist in the degenerated human CEP. Next, the morphology, proliferation capacity, cell cycle, cell surface epitope profile and differentiation capacity of these CEP-derived stem cells (CESCs) were compared with bone-marrow MSCs (BM-MSCs). Lastly, whether CESCs are a suitable candidate for BM-MSCs was evaluated. Isolated cells from degenerated human CEP were seeded in an agarose suspension culture system to screen the proliferative cell clusters. Cell clusters were chosen and expanded in vitro and were compared with BM-MSCs derived from the same patient. The morphology, proliferation rate, cell cycle, immunophenotype and stem cell gene expression of the CESCs were similar to BM-MSCs. In addition, the CESCs could be induced into osteoblasts, adipocytes, chondrocytes, and are superior to BM-MSCs in terms of osteogenesis and chondrogenesis. This study is first to demonstrate the presence of stem cells in the human degenerated CEP. These results may improve our understanding of intervertebral disc (IVD) pathophysiology and the degeneration process, and could provide cell candidates for cell-based regenerative medicine and tissue engineering

How do adolescents talk about self-harm: a qualitative study of disclosure in an ethnically diverse urban population in England

The electronic version of this article is the complete one and can be found online at: http://www.biomedcentral.com/1471-2458/13/572. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited

The ZEUS Micro Vertex Detector

During the HERA luminosity shutdown period 2000/01 the tracking system of the ZEUS experiment has been upgraded with a silicon Micro Vertex Detector (MVD). The barrel part of the detector consists of three layers of single sided silicon strip detectors, while the forward section is composed of four wheels. In this report we shortly present the assembly procedure and in more details the test beam results on the spatial resolution of half modules. The first results of a cosmic ray test are presented and the radiation monitor system is described.Comment: 8 pages, 5 figures, Talk presented at the VERTEX 2001 Workshop, 23-28 Sept. 2001, Brunnen, Switzerland. Submitted to Nucl. Instr. and Meth.

Reporting and dealing with missing quality of life data in RCTs : has the picture changed in the last decade?

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