Discovery limits for Techni-Omega production in eγe\gamma Collisions

In a strongly-interacting electroweak sector with an isosinglet vector state, such as the techni-omega, $\omega_T$, the direct $\omega_T Z \gamma$ coupling implies that an $\omega_T$ can be produced by $Z \gamma$ fusion in $e \gamma$ collisions. This is a unique feature for high energy $e^+e^-$ or $e^-e^-$ colliders operating in an $e\gamma$ mode. We consider the processes $e^- \gamma \to e^- Z\gamma$ and $e^- \gamma \to e^- W^+ W^- Z$, both of which proceed via an intermediate $\omega_T$. We find that at a 1.5 TeV $e^+e^-$ linear collider operating in an $e\gamma$ mode with an integrated luminosity of 200 fb$^{-1}$, we can discover an $\omega_T$ for a broad range of masses and widths.Comment: To appear in the Proceedings of the 29th International Conference on High Energy Physics, Vancouver, July 1998, 5 pages, Latex, 7 postscript figure

Discovery Limits for Techni-Omega Production in eγe\gamma Collisions

In a strongly-interacting electroweak sector with an isosinglet vector state, such as the techni-omega, $\omega_T$, the direct $\omega_T Z \gamma$ coupling implies that an $\omega_T$ can be produced by $Z \gamma$ fusion in $e\gamma$ collisions. This is a unique feature for high energy $e^+e^-$ or $e^-e^-$ colliders operating in an $e\gamma$ mode. We consider the processes $e^- \gamma \to e^- Z\gamma$ and $e^- \gamma \to e^- W^+ W^-Z$, both of which proceed via an intermediate $\omega_T$. We find that at a 1.5 TeV $e^+e^-$ linear collider operating in an $e\gamma$ mode with an integrated luminosity of 200 fb$^{-1}$, an $\omega_T$ can be discovered for a broad range of masses and widths.Comment: LaTex file uses revtex, epsfig, 9 pages with 7 postscript figure

Microsatellite diversity and chromosome number in natural populations of Trifolium riograndense Burkart

Twenty eight natural populations of Trifolium riograndense Burkart, an important forage legume from native pastures of the state of Rio Grande do Sul, Brazil, were evaluated for genetic diversity with eight Simple Sequences Repeats (SSR) markers. Chromosome numbers were also determined. The eight markers were polymorphic, with 35 alleles and an average of 4.37 alleles per locus, and Polymorphism Information Content (PIC) between 0.48 and 0.80. Group analysis based on Jaccard´s similarity coefficient separated the 28 accessions in nine groups, with an average genetic similarity of 0.44, indicating a high genetic variability among the populations. No evident relation between genetic distance and geographical origin was detected. The chromosome number of 2n=2x=16 was found in all populations, indicating lack of intraspecific variability for chromosome number in the species. This information on diversity can be used in conservation strategies as well as in genetic breeding programs of this species

Prognosis of patients turned down for conventional abdominal aortic aneurysm repair in the endovascular and sonographic era: Szilagyi revisited?

AbstractPurpose: The United Kingdom Small Aneurysm study has demonstrated the low risk of rupture in aneurysms less than 5.5 cm in diameter. With the advent of endoluminal techniques, patients considered unfit to undergo laparotomy are now considered for endovascular repair. However, the natural history of aneurysms larger than 5.5 cm remains uncertain, especially when severe comorbidity is present. In our center, we prospectively maintain records of all patients for whom elective aneurysm surgery was refused. This study documented the outcome of all patients referred with abdominal aortic aneurysms (AAAs) larger than 5.5 cm in diameter who were turned down for elective open repair and determined the cause of death and risk of rupture in all patients. Methods: Details of all patients with AAAs from January 5, 1989, to January 5, 1999, were recorded, and demographic details on all patients with AAAs larger than 5.5 cm were collected. Copies of death certificates were obtained from the Office of National Statistics, local in-hospital patient records, and general practitioner records. Results of postmortem examinations were also obtained. Aneurysms were stratified according to their size at presentation (5.5-5.9 cm, 6.0-7.0 cm, and > 7.0 cm), and the reasons no intervention was made were documented. Results: A total of 106 patients were turned down for elective aneurysm surgery in the 10-year period (10.6 per year). The mean age of the patients was 78.4 years (SD, 7.4), and 70 were men and 36 were women. At the end of the study, 76 patients (71.7%) had died. Overall, the 3-year survival rate was 17%. Patients with AAAs larger than 7.0 cm lived a median of 9 months. A ruptured aneurysm was certified as a cause of death in 36% of the patients with an AAA of 5.5 to 5.9 cm, in 50% of the patients with an AAA of 6 to 7.0 cm, and 55% of the patients with an AAA larger than 7.0 cm. Reasons given for not intervening were patient refusal (31 cases), the patient being “unfit for surgery” (18 cases), the “advanced age” of the patient (18 cases), cardiac disease (9 cases), cancer (9 cases), respiratory disease (6 cases), and other (15 cases). Conclusion: Although we recognize the problems with death certification, we found that rupture was a significant cause of death in patients with an untreated AAA that was larger than 5.5 cm. Although little difference in outcome was observed in aneurysms in the 5.5 to 7.0 cm size range, patients with an AAA that was larger than 7.0 cm seemed to have a much poorer prognosis. (J Vasc Surg 2001;33:752-7.

Lupus anticoagulant in patients with peripheral vascular disease: A prospective study

Objective:To assess the incidence of lupus anticoagulant (LAC) in patients with peripheral vascular disease.Design:Prospective clinical study.Setting:University Hospital.Materials:20 patients with claudication (group 2), 20 patients with critical ischaemia (group 3) and 20 patients prior to elective abdominal aortic aneurysm surgery (group 4) were compared to 20 general surgical controls (group 1).Chief outcome measures:Venous blood samples for coagulation assay.Main results:Positive results for LAC by the Dilute Russell's viper venom time (DRVVT) with the platelet neutralisation procedure were present in 26 out of 60 vascular patients compared with none of the 20 general surgical controls. The three vascular groups showed a similar prevalence of LAC and this differed significantly from that in the control group (x2 = 10.94, p = 0.0009). Of the 26 positive results only three were associated with an abnormal activated partial thromboplastin time (APTT), which has previously been used as a marker for the presence of LAC activity. Fibrinogen levels were raised in seven of 20 patients in group 2 but were normal in the remaining vascular groups (p = 0.001). The mean factor VII level (124.1 units dl−1) in group 2 was higher than the mean of the remaining vascular patients (109.3 units dl−1, p < 0.05).Conclusions:The high prevalence of LAC in patients with peripheral vascular disease and the associated increased risk of early graft thrombosis may justify routine testing by DRVVT prior to reconstructive vascular surgery. Treatment of these patients with antiplatelet agents or formal anticoagulation perioperatively should be considered

PYTHIA 6.4 physics and manual

The Pythia program can be used to generate high-energy-physics 'events', i.e. sets of outgoing particles produced in the interactions between two incoming particles. The objective is to provide as accurate as possible a representation of event properties in a wide range of reactions, within and beyond the Standard Model, with emphasis on those where strong interactions play a role, directly or indirectly, and therefore multihadronic final states are produced. The physics is then not understood well enough to give an exact description; instead the program has to be based on a combination of analytical results and various QCD-based models. This physics input is summarized here, for areas such as hard subprocesses, initial- and final-state parton showers, underlying events and beam remnants, fragmentation and decays, and much more. Furthermore, extensive information is provided on all program elements: subroutines and functions, switches and parameters, and particle and process data. This should allow the user to tailor the generation task to the topics of interest