Numerical study of radiative corrections in the low Q2Q^2 region at HERA

A detailed numerical study of radiative corrections in the low $Q^2$ region at the HERA $ep$ collider was performed. The specific case of the total photoproduction cross section measurement was taken as an example. Two different programs, TERAD91 and HERACLES4.2, were used to get an estimation of the size of radiative effects. It was found that radiative corrections can be quite large in some points of the space of leptonic $(x,y)$ variables. However, after imposing experimentally feasible cuts on the radiated photon and the hadronic final state one gets corrections at the level of a few per cent.Comment: 12 pages, 6 figures (not included), Deutsches Electronen Synchrotron preprint DESY 92-173, LaTex, hardcopy of the figures available upon request to [email protected]

Late Quaternary Vegetation History of Sulphur Lake, Southwest Yukon Territory, Canada

Paleoecological studies based on the analysis of pollen in lake sediments offer the potential for high resolution and well-dated independent records of past vegetation and climate. A 5 m sediment core was raised from the deepest section of Sulphur Lake, located in the southwest Yukon (60.95°N, 137.95°W; 847 m a.s.l.). The pollen spectra indicate that before 11250 yr BP, the vegetation was a herbaceous tundra marked by the presence of Artemisia. However, the date of the establishment of this initial vegetation cannot be secured because of problems with the basal radiocarbon date and the lack of a reliable chronology of regional deglaciation. A birch shrub tundra prevailed between 11250 and 10250 yr BP and was then replaced by a discontinuous poplar woodland. Juniperus populations expanded at 9500 yr BP, and by 8400 yr BP, Picea invaded the region. The white spruce forest that occupies the region today was established by approximately 8000 yr BP. Alnus crispa increased at 6000 yr BP, but the simultaneous increase in Picea mariana found at most sites in the Yukon was not present at Sulphur Lake. Black spruce was never a dominant component of the vegetation in the southwest Yukon, as it was in the south-central Yukon between 6100 and 4100 yr BP.Les études paléoécologiques fondées sur l'analyse de pollens de sédiments lacustres offrent la possibilité d'obtenir une chronologie de la paléovégétation et du paléoclimat à haute résolution et avec une datation précise. Une carotte de sédiment de 5 m a été prélevée dans la section la plus profonde de Sulphur Lake, situé au sud-ouest du Yukon (60,95° N., 137,95° O.; 847 m alt.). D'après les spectres polliniques, la végétation a été une toundra herbacée marquée par la présence d'Artemisia avant 11 250 ans B.P. Cependant, la date de colonisation de cette végétation ne peut être déterminée de façon définitive à cause des problèmes de datation du début de la séquence sédimentologique et l'absence d'une chronologie fiable de la déglaciation régionale. Une toundra arbustive à bouleau a prédominé entre 11250 B.P. et 10250 ans B.P., et a ensuite été remplacée par une région boisée de peuplier discontinu. Les populations de Juniperus ont augmenté vers 9500 ans B.P. et, vers 8400 ans B.P., Picea a colonisé la région. La forêt relativement fermée d'épinettes blanches qui occupe la région aujourd'hui s'est établie vers 8000 ans B.P. Alnus crispa s'est répandu il y a environ 6000 ans B.P. Alors qu'on retrouve une augmentation de Picea mariana à cette époque dans la plupart des sites dans le Territoire du Yukon, celle-ci n'a pas eu lieu à Sulphur Lake. L'épinette noire n'a jamais été une composante dominante de la végétation au sud-ouest du Yukon comme elle l'a été entre 6100 et 4100 ans B.P. au centre-sud du Yukon

APPLICATION OF ALLOMETRY FOR DETERMINATION OF STRENGTH PROFILE IN YOUNG FEMALE ATHLETES FROM DIFFERENT SPORTS

The goal of the study was to determine a strength profile in young female athletes practising different sports and to use allometry to evaluate muscular strength with respect to body mass. The study included 42 women who practised taekwondo (n = 10), weightlifting (n = 10), canoeing (n = 14) and speed skating (n = 8). Measurements of maximal muscle torques under static conditions in 10 groups of flexors and extensors of the elbow, shoulder, hip, knee and trunk were carried out. The MANCOVA procedure was employed to compare means between the groups. A logarithm of body mass was adopted as a covariate. Relationships between body mass and muscle torques in each muscle group were determined using a procedure of linear regression. The analysis of residuals was employed for the evaluation of maximal muscle torques. Mean values of logarithms of maximal muscle torques were significantly different for the representatives of individual sports and they depended on the logarithm of body mass. It was proposed to use a mean of residuals normalized for individual muscle groups as a synthetic strength index (mean of the strength profile). The women practising canoeing were characterized by the highest strength index. Its lowest values were obtained by weightlifting and taekwondo athletes. Differences in strength profiles in the tested athletes were attributed to the specific nature of their sports. It is suggested to use an allometric relationship scaled by body mass for strength assessment

Application of Leg, Vertical, and Joint Stiffness in Running Performance: A Literature Overview

Stiffness, the resistance to deformation due to force, has been used to model the way in which the lower body responds to landing during cyclic motions such as running and jumping. Vertical, leg, and joint stiffness provide a useful model for investigating the store and release of potential elastic energy via the musculotendinous unit in the stretch-shortening cycle and may provide insight into sport performance. This review is aimed at assessing the effect of vertical, leg, and joint stiffness on running performance as such an investigation may provide greater insight into performance during this common form of locomotion. PubMed and SPORTDiscus databases were searched resulting in 92 publications on vertical, leg, and joint stiffness and running performance. Vertical stiffness increases with running velocity and stride frequency. Higher vertical stiffness differentiated elite runners from lower-performing athletes and was also associated with a lower oxygen cost. In contrast, leg stiffness remains relatively constant with increasing velocity and is not strongly related to the aerobic demand and fatigue. Hip and knee joint stiffness are reported to increase with velocity, and a lower ankle and higher knee joint stiffness are linked to a lower oxygen cost of running; however, no relationship with performance has yet been investigated. Theoretically, there is a desired “leg-spring” stiffness value at which potential elastic energy return is maximised and this is specific to the individual. It appears that higher “leg-spring” stiffness is desirable for running performance; however, more research is needed to investigate the relationship of all three lower limb joint springs as the hip joint is often neglected. There is still no clear answer how training could affect mechanical stiffness during running. Studies including muscle activation and separate analyses of local tissues (tendons) are needed to investigate mechanical stiffness as a global variable associated with sports performance

Late Holocene Pollen Stratigraphy in Four Northeastern United States Lakes

Four pollen diagrams from Maine, New York, and Pennsylvania provide fine resolution (40 or 80 years) records of vegetation change in northeastern United States during the past 2000 years. A long term increase in pollen accumulation rates (PAR) of Picea occurred at the three sites in Maine and New York. Around 1100 years ago, Tsuga and Fagus decreased and Quercus and Castanea increased at Ely Lake in northeastern Pennsylvania. Around 500 years ago, Tsuga and Fagus greatly decreased in Maine and northern New York, while in northeastern Pennsylvania there was an increase in Tsuga and Fagus and a decrease in Quercus and Castanea pollen. Non-arboreal PAR were negligible prior to the European settlement of the area, after which there was an abrupt increase in non-arboreal pollen types.Quatre diagrammes polliniques des états du Maine, de New York et de Pennsylvanie illustrent de manière détaillée (40 ou 80 ans) les changements survenus dans la végétation du nord-est des États-Unis sur une période de 2000 ans. Les trois diagrammes des états du Maine et de New York enregistrent un accroissement continu de l'influx pollinique (PAR) de Picea. Il y a environ 1100 ans, Tsuga et Fagus ont subi une diminution, tandis que Quercus et Castanea ont augmenté à Ely Lake, dans le nord-est de la Pennsylvanie. Il y a 500 ans, Tsuga et Fagus ont considérablement diminué dans les états du Maine et de New York, alors que leur représentation pollinique augmentait dans le nord-est de la Pennsylvanie et que Quercus et Castanea diminuaient. Les influx polliniques des herbacés étaient minimes avant l'arrivée des Européens dans la région, après quoi ces taxons ont connu une augmentation subite.Vier Pollen-Diagramme von Maine, New York und Pennsylvania geben detaillierte Auflôsungs-Nachweise der Vegetationswechsel im Nordosten der Vereinigten Staaten wàhrend der letzten 2000 Jahre. Ein langfristiges Anwachsen der Pollen-Akkumulationsraten (PAR) von Picea trat an den drei Fundstellen in Maine und im Staat New York auf. Vor ungefàhr 11000 Jahren, nahmen am Ely-See in Nordost-Pennsylvania Tsuga and Fagus ab und Quercus und Castanea zu. Vor ungefàhr 500 Jahren nahmen in Maine und im Norden des staats New York Tsuga und Fagus stark ab, wàhrend in Nordost-Pennsylvania Tsuga und Fagus zunahmen und Quercus und Casfanea-Pollen abnahmen. Die nicht von Bàumen stammenden PAR waren gering, bevor das Gebiet von Europàern besiedelt wurde, wàhrend danach die nicht von Bàumen stammenden Pollenarten plôtzlich anwuchsen

Antibiotic susceptibility and ability to form biofilm of Listeria monocytogenes strains isolated from frozen vegetables

L. monocytogenes poses a serious threat to public health, since most cases of listeriosis are connected with eating contaminated food. L. monocytogenes is often detected both in fresh and frozen vegetables. The aim of this study was to evaluate the antibiotic susceptibility and ability to form biofilm of L. monocytogenes strains isolated from frozen vegetable mixtures in Poland. Ninetynine genetically different strains were found among 100 isolates of L. monocytogenes. Among the 99 strains, 80 (80.8%) were susceptible to all tested antibiotics. Nineteen (19.2%) strains were resistant to one or more antibiotics. From this group of L. monocytogenes strains, most strains were resistant to erythromycin (16; 16,1%), penicillin (15; 15.1%), meropenem (12; 12.1%), cotrimoxazole (12; 12.1%), and ampicillin (3; 3.1%). According to the obtained results, differences in intensity of biofilm, both between those isolated in successive years and in the particular year, were observed. Performed analysis showed statistically insignificant faint negative correlation (r=–0.088) between the number of antibiotics to which strains were resistant and the intensity of biofilm formation by them. Food contamination with L. monocytogenes poses a threat to consumers, therefore it is necessary to monitor their antibiotic susceptibility, ability to form biofilm, and genetic similarity, in order to evaluate the strains persistence time in plant