5,753 research outputs found
Invasion and establishment of White Pine (Pinus strobus L.) in the Saxon Switzerland National Park
Die naturnahen WaldĂśkosysteme mit Pinus sylvestris auf Sandsteinfelsen im Nationalpark Sächsische Schweiz sind durch die Ausbreitung der Weymouth-Kiefer potenziell gefährdet. Wachstum und Etablierung der VerjĂźngung sind besonders in lichten Beständen vorzugsweise auf oligotrophen Standorten erfolgreich. Die biologischen und Ăśkologischen Eigenschaften der nichteinheimischen Baumart begĂźnstigen ihre Ausbreitung: häufige Fruktifikation, hohes Regenerationspotenzial, weiter Samenflug und rasches Wachstum. Die Weymouth-Kiefer findet im Nationalpark klimatisch und standortĂśkologisch beste Wuchsbedingungen vor. Erste Anzeichen einer erfolgreichen Ausbreitung sind erkennbar. Aufgrund ihres Konkurrenzpotenzials wird die Baumart sich auch in den naturnahen Beständen des Nationalparkes etablieren kĂśnnen. Die Streuakkumulation ist Ursache eines RĂźckganges der Kraut- und Moosschicht in den Fels-Kiefernwäldern. Effekte der Ausbreitung, die irreversible Folgen fĂźr das Ăkosystem hervorrufen kĂśnnen, werden unter Bedingungen eines differenzierten Managements im Nationalpark diskutiert (Entwicklungsszenarien).The ecosystem of the natural Scots Pine forests on sandstone outcrops in the National Park Saxon Switzerland is potentially endangered by the spreading of White Pine. The establishment and growth of regeneration are especially successful in open stands, preferably on oligotrophic soils. Biological and ecological qualities of White Pine facilitate its establishment: frequent fructification, high regeneration potential, wide dispersal of seeds and rapid growth. White Pine finds optimal growth conditions with respect to climate and site ecology in the National Park. First indications of local extensions in range are noticeable. With its competition potential, the tree species may also become established in near-natural and semi-natural stands of the National Park. Competition by White Pine and accumulation of its needles on the soil result in a decline in understorey and ground vegetation (herb and moss layers) in the pine forests on rocky ground. The effects of spreading would have irreversible consequences for the ecosystem. Methods of preventing this using different management strategies for a variety of developmental scenarios are discussed
Improving the Quality of EEG Data in Patients With Alzheimers Disease Using ICA
Does Independent Component Analysis (ICA) denature EEG
signals? We applied ICA to two groups of subjects (mild Alzheimer
patients and control subjects). The aim of this study was to examine
whether or not the ICA method can reduce both group diÂŽerences and
within-subject variability. We found that ICA diminished Leave-One-
Out root mean square error (RMSE) of validation (from 0.32 to 0.28),
indicative of the reduction of group diÂŽerence. More interestingly, ICA
reduced the inter-subject variability within each group (ž = 2:54 in the
¹ range before ICA, ž = 1:56 after, Bartlett p = 0.046 after Bonfer-
roni correction). Additionally, we present a method to limit the impact
of human error (' 13:8%, with 75.6% inter-cleaner agreement) during
ICA cleaning, and reduce human bias. These ÂŻndings suggests the novel
usefulness of ICA in clinical EEG in Alzheimer's disease for reduction of
subject variability
The Minimal Supersymmetric Standard Model: Group Summary Report
CONTENTS: 1. Synopsis, 2. The MSSM Spectrum, 3. The Physical Parameters, 4.
Higgs Boson Production and Decays, 5. SUSY Particle Production and Decays, 6.
Experimental Bounds on SUSY Particle Masses, 7. References.Comment: 121 pages, latex + epsfig, graphicx, axodraw, Report of the MSSM
working group for the Workshop "GDR-Supersym\'etrie",France. Rep. PM/98-4
Effect of housing system on reproductive behaviour and on some endocrinological and seminal parameters of donkey stallions
Reproductive management of male donkeys employed for artificial breeding has been poorly studied. The aim of this study was to evaluate the effect of housing system, with the animals grouped together in a paddock or kept in individual boxes, on sexual behaviour, cortisol and testosterone concentration and seminal characteristics of adult male donkeys. The study included four Amiata donkey jacks (stallions) from which ejaculates, saliva and blood were collected during two distinct 3 weeks periods, one in the group and one in the box housing system. Time needed for semen collection was shorter when donkeys were kept in paddocks compared to when they were kept in single boxes (14:57 Âą 07:27 and 20:52 Âą 09:31 min, p < .05). Native semen characteristics were not influenced by housing system, while cooled preservation in an Equitainer(ÂŽ) showed that sperm motility parameters were significantly higher during the paddock period compared to the box period. Salivary cortisol was influenced by housing system, both before and 60 min after ejaculation, being statistically higher when donkeys were housed in paddocks. On the contrary, overall and basal testosterone concentrations were significantly higher when animals were kept in boxes. In conclusion, in the present study, good quality semen could be successfully collected from donkeys irrespective of the housing system despite some differences in hormone concentrations
Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter
This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered
Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV
A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay
channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7
TeV is presented. The data were collected at the LHC, with the CMS detector,
and correspond to an integrated luminosity of 4.6 inverse femtobarns. No
significant excess is observed above the background expectation, and upper
limits are set on the Higgs boson production cross section. The presence of the
standard model Higgs boson with a mass in the 270-440 GeV range is excluded at
95% confidence level.Comment: Submitted to JHE
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