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  • Springer  (131,752)
  • Cell Press  (21,516)
  • Copernicus  (16,224)
  • MDPI Publishing  (15,862)
  • 2015-2019  (127,392)
  • 2000-2004  (57,962)
  • 2017  (127,392)
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  • 2001  (27,039)
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  • 2015-2019  (127,392)
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  • 1
    Publication Date: 2020-11-18
    Description: Volcanic crises are complex and especially challenging to manage. Volcanic unrest is characterised by uncertainty about whether an eruption will or will not take place, as well as its possible location, size and evolution. Planning is further complicated by the range of potential hazards and the variety of disciplines involved in forecasting and responding to volcanic emergencies. Effective management is favoured at frequently active volcanoes, owing to the experience gained through the repeated ‘testing’ of systems of communication. Even when plans have not been officially put in place, the groups involved tend to have an understanding of their roles and responsibilities and those of others. Such experience is rarely available at volcanoes that have been quiescent for several generations. Emergency responses are less effective, not only because of uncertainties about the volcanic system itself, but also because scientists, crisis directors, managers and the public are inexperienced in volcanic unrest. In such situations, tensions and misunderstandings result in poor communication and have the potential to affect decision making and delay vital operations. Here we compare experiences on communi- cating information during crises on volcanoes reawakening after long repose (El Hierro in the Canary Islands) and in frequent eruption (Etna and Stromboli in Sicily). The results provide a basis for enhancing commu- nication protocols during volcanic emergencies.
    Description: Published
    Description: 1-17
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: N/A or not JCR
    Keywords: Etna volcano ; Stromboli volcano ; Canary Islands ; volcanic emergencies ; communication ; volcanic crisis ; Procedures for Communications During Volcanic Emergencies ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 2
    Publication Date: 2017-08-30
    Description: Predicting future thaw slump activity requires a sound understanding of the atmospheric drivers and geomorphic controls on mass wasting across a range of time scales. On sub-seasonal time scales, sparse measurements indicate that mass wasting at active slumps is often limited by the energy available for melting ground ice, but other factors such as rainfall or the formation of an insulating veneer may also be relevant. To study the sub-seasonal drivers, we derive topographic changes from single-pass radar interferometric data acquired by the TanDEM-X satellite (12 m resolution). The high vertical precision (around 30 cm), frequent observations (11 days) and large coverage (5000 km2) allow us to track volume losses as drivers such as the available energy change during summer in two study regions. We find that thaw slumps in the Tuktoyaktuk coastlands, Canada, are not energy limited in June, as they undergo limited mass wasting (height loss of around 0 cm/day) despite the ample available energy, indicating the widespread presence of an insulating snow or debris veneer. Later in summer, height losses generally increase (around 3 cm/day), but they do so in distinct ways. For many slumps, mass wasting tracks the available energy, a temporal pattern that is also observed at coastal yedoma cliffs on the Bykovsky Peninsula, Russia. However, the other two common temporal trajectories are asynchronous with the available energy, as they track strong precipitation events or show a sudden speed-up in late August, respectively. The observed temporal patterns are poorly related to slump characteristics like the slump area. The contrasting temporal behaviour of nearby thaw slumps highlights the importance of complex local and temporally varying controls on mass wasting.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , notRev , info:eu-repo/semantics/article
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  • 3
    Publication Date: 2017-09-10
    Description: Sediment delivery to the abyssal regions of the oceans is an integral process in the source to sink cycle of material derived from adjacent continents and islands. The Zambezi River, the largest in southern Africa, delivers vast amounts of material to the inner continental shelf of central Mozambique. The aim of this contribution is to better constrain sediment transport pathways to the abyssal plains using the latest, regional, high-resolution multibeam bathymetry data available, taking into account the effects of bottom water circulation, antecedent basin morphology and sea-level change. Results show that sediment transport and delivery to the abyssal plains is partitioned into three distinct domains; southern, central and northern. Sediment partitioning is primarily controlled by changes in continental shelf and shelf-break morphology under the influence of a clockwise rotating shelf circulation system. However, changes in sealevel have an overarching control on sediment delivery to particular domains. During highstand conditions, such as today, limited sediment delivery to the submarine Zambezi Valley and Channel is proposed, with increased sediment delivery to the deepwater basin being envisaged during regression and lowstand conditions. However, there is a pronounced along-strike variation in sediment transport during the sea-level cycle due to changes in the width, depth and orientation of the shelf. This combination of features outlines a sequence stratigraphic concept not generally considered in the strike-aligned shelf-slope-abyssal continuum.
    Repository Name: EPIC Alfred Wegener Institut
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  • 4
    Publication Date: 2017-11-06
    Description: A suite of oxygenated volatile organic compounds (OVOCs – acetaldehyde, acetone, propanal, butanal and butanone) were measured concurrently in the surface water and atmosphere of the South China Sea and Sulu Sea in November 2011. A strong correlation was observed between all OVOC concentrations in the surface seawater along the entire cruise track, except for acetaldehyde, suggesting similar sources and sinks in the surface ocean. Additionally, several phytoplankton groups, such as haptophytes or pelagophytes, were also correlated to all OVOCs indicating that phytoplankton may be an important source for marine OVOCs in the South China and Sulu Seas. Humic and protein like fluorescent dissolved organic matter (FDOM) components seemed to be additional precursors for butanone and acetaldehyde. The atmospheric OVOC mixing ratios were relative high compared with literature values, suggesting the coastal region of North Borneo as a local hot spot for atmospheric OVOCs. The flux of atmospheric OVOCs was largely into the ocean for all 5 gases, with a few important exceptions near the coast of Borneo. The calculated amount of OVOCs entrained into the ocean seemed to be an important source of OVOCs to the surface ocean. When the fluxes were out of the ocean, marine OVOCs were found to be enough to control the local measured OVOC distribution in the atmosphere. Based on our model calculations, at least 0.4 ppb of marine derived acetone and butanone can reach the upper troposphere, where they may have an important influence on hydrogen oxide radical formation over the western Pacific Ocean.
    Repository Name: EPIC Alfred Wegener Institut
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  • 5
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    Copernicus
    In:  EPIC3Geoscientific Model Development, Copernicus, 11, pp. 753-769
    Publication Date: 2018-03-28
    Description: The Extrapolar SWIFT model is a fast ozone chemistry scheme for interactive calculation of the extrapolar stratospheric ozone layer in coupled general circulation models (GCMs). In contrast to the widely used prescribed ozone, the SWIFT ozone layer interacts with the model dynamics and can respond to atmospheric variability or climatological trends. The Extrapolar SWIFT model employs a repro-modelling approach, where algebraic functions are used to approximate the numerical output of a full stratospheric chemistry and transport model (ATLAS). The full model solves a coupled chemical differential equations system with 55 initial and boundary conditions (mixing ratio of various chemical species and atmospheric parameters). Hence the rate of change of ozone over 24  h is a function of 55 variables. Using covariances between these variables, we can find linear combinations in order to reduce the parameter space to the following nine basic variables: latitude, pressure altitude, temperature, local ozone column, mixing ratio of ozone and of the ozone depleting families (Cly, Bry, NOy and HOy). We will show that these 9 variables are sufficient to characterize the rate of change of ozone. An automated procedure fits a polynomial function of fourth degree to the rate of change of ozone obtained from several simulations with the ATLAS model. One polynomial function is determined per month which yields the rate of change of ozone over 24 h. A key aspect for the robustness of the Extrapolar SWIFT model is to include a wide range of stratospheric variability in the numerical output of the ATLAS model, also covering atmospheric states that will occur in a future climate (e.g. temperature and meridional circulation changes or reduction of stratospheric chlorine loading). For validation purposes, the Extrapolar SWIFT model has been integrated into the ATLAS model replacing the full stratospheric chemistry scheme. Simulations with SWIFT in ATLAS have proven that the systematic error is small and does not accumulate during the course of a simulation. In the context of a 10 year simulation, the ozone layer, simulated by SWIFT, shows a stable annual cycle, with inter-annual variations comparable to the ATLAS model. The application of Extrapolar SWIFT requires the evaluation of polynomial functions with 30–100 terms. Nowadays, computers can calculate such polynomial functions at thousands of model grid points in seconds. SWIFT provides the desired numerical efficiency and computes the ozone layer 104 times faster than the chemistry scheme in the ATLAS CTM.
    Repository Name: EPIC Alfred Wegener Institut
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  • 6
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    Copernicus
    In:  EPIC3The Cryosphere, Copernicus, 11(5), pp. 2383-2391
    Publication Date: 2017-10-24
    Description: Ice retreat in the eastern Eurasian Arctic is a consequence of atmospheric and oceanic processes and regional feedback mechanisms acting on the ice cover, both in winter and summer. A correct representation of these processes in numerical models is important, since it will improve predictions of sea ice anomalies along the Northeast Passage and beyond. In this study, we highlight the importance of winter ice dynamics for local summer sea ice anomalies in thickness, volume and extent. By means of airborne sea ice thickness surveys made over pack ice areas in the south-eastern Laptev Sea, we show that years of offshore-directed sea ice transport have a thinning effect on the late-winter sea ice cover. To confirm the preconditioning effect of enhanced offshore advection in late winter on the summer sea ice cover, we perform a sensitivity study using a numerical model. Results verify that the preconditioning effect plays a bigger role for the regional ice extent. Furthermore, they indicate an increase in volume export from the Laptev Sea as a consequence of enhanced offshore advection, which has far-reaching consequences for the entire Arctic sea ice mass balance. Moreover we show that ice dynamics in winter not only preconditions local summer ice extent, but also accelerate fast-ice decay.
    Repository Name: EPIC Alfred Wegener Institut
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  • 7
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    Springer
    In:  EPIC3Hamburger Klimabericht – Wissen über Klima, Klimawandel und Auswirkungen in Hamburg und Norddeutschland, Springer, 311 p., pp. 90-107, ISBN: 978-3-662-55378-7
    Publication Date: 2017-11-09
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 8
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    Springer
    In:  EPIC3Faszination Meeresforschung, Book, Berlin, Springer, 573 p., pp. 455-460, ISBN: 978-3-662-49713-5
    Publication Date: 2017-01-20
    Description: Fast die Hälfte der gesamten weltweit durch Marikultur erzeugten Biomasse sind Makroalgen. Die unterschiedlich gelierenden Bestandteile ihrer Zellwände (Hydrokolloide) werden industriell genutzt. Offensichtlicher für den Verbraucher ist die Verwendung als Lebensmittel, z.B., die Rotalge Pyropia als Nori für Sushi. Es wird erklärt, warum diese Produkte teuer sind.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 9
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    Springer
    In:  EPIC3Faszination Meeresforschung-Ein ökologisches Lesebuch, Faszination Meeresforschung-Ein ökologisches Lesebuch, Berlin, Springer, 573 p., pp. 385-397, ISBN: 978-3-662-49713-5
    Publication Date: 2018-02-16
    Repository Name: EPIC Alfred Wegener Institut
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  • 10
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    Springer
    In:  EPIC3Faszination Meeresforschung, ein ökologisches Lesebuch, Faszination Meeresforschung, Springer, pp. 261-272, ISBN: 978-3-662-49713-5
    Publication Date: 2018-02-15
    Repository Name: EPIC Alfred Wegener Institut
    Type: Inbook , peerRev
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  • 11
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    Springer
    In:  EPIC3Faszination Meeresforschung - Ein ökologisches Lesebuch, 2. Auflage, Berlin, Springer, 573 p., pp. 103-112, ISBN: 978-3-662-49713-5
    Publication Date: 2017-01-26
    Repository Name: EPIC Alfred Wegener Institut
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  • 12
    Publication Date: 2017-12-19
    Description: Climate trends in the Antarctic region remain poorly characterized, owing to the brevity and scarcity of direct climate observations and the large magnitude of interannual to decadal-scale climate variability. Here, within the framework of the PAGES Antarctica2k working group, we build an enlarged database of ice core water stable isotope records from Antarctica, consisting of 112 records. We produce both unweighted and weighted isotopic (δ18O) composites and temperature reconstructions since 0 CE, binned at 5- and 10-year resolution, for seven climatically distinct regions covering the Antarctic continent. Following earlier work of the Antarctica2k working group, we also produce composites and reconstructions for the broader regions of East Antarctica, West Antarctica and the whole continent. We use three methods for our temperature reconstructions: (i) a temperature scaling based on the δ18O–temperature relationship output from an ECHAM5-wiso model simulation nudged to ERA-Interim atmospheric reanalyses from 1979 to 2013, and adjusted for the West Antarctic Ice Sheet region to borehole temperature data, (ii) a temperature scaling of the isotopic normalized anomalies to the variance of the regional reanalysis temperature and (iii) a composite-plus-scaling approach used in a previous continent-scale reconstruction of Antarctic temperature since 1 CE but applied to the new Antarctic ice core database. Our new reconstructions confirm a significant cooling trend from 0 to 1900 CE across all Antarctic regions where records extend back into the 1st millennium, with the exception of the Wilkes Land coast and Weddell Sea coast regions. Within this long-term cooling trend from 0 to 1900 CE, we find that the warmest period occurs between 300 and 1000 CE, and the coldest interval occurs from 1200 to 1900 CE. Since 1900 CE, significant warming trends are identified for the West Antarctic Ice Sheet, the Dronning Maud Land coast and the Antarctic Peninsula regions, and these trends are robust across the distribution of records that contribute to the unweighted isotopic composites and also significant in the weighted temperature reconstructions. Only for the Antarctic Peninsula is this most recent century-scale trend unusual in the context of natural variability over the last 2000 years. However, projected warming of the Antarctic continent during the 21st century may soon see significant and unusual warming develop across other parts of the Antarctic continent. The extended Antarctica2k ice core isotope database developed by this working group opens up many avenues for developing a deeper understanding of the response of Antarctic climate to natural and anthropogenic climate forcings. The first long-term quantification of regional climate in Antarctica presented herein is a basis for data–model comparison and assessments of past, present and future driving factors of Antarctic climate.
    Repository Name: EPIC Alfred Wegener Institut
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  • 13
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    Springer
    In:  EPIC3Klimawandel in Deutschland: Entwicklung, Folgen, Risiken und Perspektiven, Klimawandel in Deutschland: Entwicklung, Folgen, Risiken und Perspektiven, Berlin, Springer, 7 p., pp. 103-109, ISBN: 978-3-662-50396-6
    Publication Date: 2018-01-29
    Description: Extremereignisse zeigen am augenfälligsten, wie verletzlich Deutschland gegenüber dem Klima und seinen Veränderungen ist. Betrachtet man Extremereignisse genauer, verursachten in den vergangenen 20 Jahren Hochwasser die größten Schäden (Ernst Rauch, Münchener Rückversicherungs-Gesellschaft, persönliche Mitteilung). In der Wissenschaft herrscht Einigkeit darüber, dass sich der zukünftige globale Wasserkreislauf durch steigende atmosphärische Treibhausgaskonzentrationen verändern wird (Kirtman et al. 2013). Doch selbst bei der vergleichsweise guten Datenlage für Deutschland ist es unsicher, ob sich die Auftrittsrate – die Anzahl an Ereignissen pro Jahr – von Hochwasser verändert (Trend), wie stark eventuell vorliegende Trends sind und wie stark der Klimawandel ursächlich einwirkt. Diese Zuschreibung der Ursachen wird als Attribution bezeichnet. Gleichzeitig bilden diese Informationen eine wichtige Grundlage für Entscheidungsträger, die über Mitigations- und Anpassungsstrategien befinden. Die damit verbundenen Unsicherheiten müssen daher möglichst transparent kommuniziert werden, um einen Umgang damit zu ermöglichen. Ihre Quellen und Ausmaße werden im Folgenden am Beispiel der Elbehochwasser ausführlich illustriert. Für die Elbe ist der Wissensstand aufgrund der guten Datenqualität und umfangreicher wissenschaftlicher Untersuchungen relativ hoch. Für andere Flüsse (▶ Kap. 10) und andere Ereignistypen sind die Unsicherheiten zum Teil wesentlich größer.
    Repository Name: EPIC Alfred Wegener Institut
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  • 14
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    Springer
    In:  EPIC3Boundary-Layer Meteorology, Springer, 162:91, pp. 1-26
    Publication Date: 2017-10-20
    Description: A new quasi-analytical mixed-layer model is formulated describing the evolution of the convective atmospheric boundary layer (ABL) during cold-air outbreaks (CAO) over polar oceans downstream of the marginal sea-ice zones. The new model is superior to previous ones since it predicts not only temperature and mixed-layer height but also the height-averaged horizontal wind components. Results of the mixed-layer model are compared with dropsonde and aircraft observations carried out during several CAOs over the Fram Strait and also with results of a 3D non-hydrostatic (NH3D) model. It is shown that the mixed-layer model reproduces well the observed ABL height, temperature, low-level baroclinicity and its influence on the ABL wind speed. The mixed-layer model underestimates the observed ABL temperature only by about 10 %, most likely due to the neglect of condensation and subsidence. The comparison of the mixed-layer and NH3D model results shows good agreement with respect to wind speed including the formation of wind-speed maxima close to the ice edge. It is concluded that baroclinicity within the ABL governs the structure of the wind field while the baroclinicity above the ABL is important in reproducing the wind speed. It is shown that the baroclinicity in the ABL is strongest close to the ice edge and slowly decays further downwind. Analytical solutions demonstrate that the e-folding distance of this decay is the same as for the decay of the difference between the surface temperature of open water and of the mixed-layer temperature. This distance characterizing cold-air mass transformation ranges from 450 to 850 km for high-latitude CAOs.
    Repository Name: EPIC Alfred Wegener Institut
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  • 15
    Publication Date: 2017-06-23
    Description: Amphipoda from the superfamily Lysianassoidea Dana, 1849 play an important role in Southern Ocean benthic food webs due to their high biomass, abundance and predominantly scavenging mode of feeding. Our knowledge on the lysianassoid fauna, even in well-studied areas of the Western Antarctic Peninsula, is incomplete. Here we report the findings of an integrated study of lysianassoid amphipods of Potter Cove, King George Island/Isla 25 de Mayo (KGI), combining morphological and molecular species identification (COI barcoding) methods, investigating more than 41,000 specimens from baited traps. For comparison, 2,039 specimens from the adjacent Marian Cove were analysed. Ten lysianassoid species were recorded in the deeper outer Potter Cove, whereas the inner cove (〈50 m) was dominated by a single species, Cheirimedon femoratus Pfeffer, 1888 (99.44% relative abundance). It is hypothesised that the impoverished lysianassoid fauna inside the meltwater-influenced inner cove represents a model for future conditions along the Western Antarctic Peninsula under conditions of increased glacial melting. Abyssorchomene charcoti (Chevreux, 1912) and Orchomenella pinguides Walker, 1903 were recorded in KGI waters for the first time. Furthermore, one new lysianassoid amphipod species of the genus Orchomenella Sars, 1890 is described: Orchomenella infinita sp. n. Seefeldt, 2017. First-time DNA barcode data was established for Cheirimedon femoratus, Hippomedon kergueleni Miers, 1875, Orchomenella rotundifrons K.H. Barnard, 1932 and Orchomenella infinita sp. n.
    Repository Name: EPIC Alfred Wegener Institut
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  • 16
    Publication Date: 2017-08-10
    Description: The Arctic represents an extreme habitat for phototrophic algae due to long periods of darkness caused by the polar night (~4 months darkness). Benthic diatoms, which dominate microphytobenthic communities in shallow water regions, can survive this dark period, but the underlying physiological and biochemical mechanisms are not well understood. One of the potential mechanisms for long-term dark survival is the utilisation of stored energy products in combination with a reduced basic metabolism. In recent years, water temperatures in the Arctic increased due to an ongoing global warming. Higher temperatures could enhance the cellular energy requirements for the maintenance metabolism during darkness and, therefore, accelerate the consumption of lipid reserves. In this study, we investigated the macromolecular ratios and the lipid content and composition of Navicula cf. perminuta Grunow, an Arctic benthic diatom isolated from the microphytobenthos of Adventfjorden (Svalbard, Norway), over a dark period of 8 weeks at two different temperatures (0 and 7 °C). The results demonstrate that N. perminuta uses the stored lipid compound triacylglycerol (TAG) during prolonged dark periods, but also the pool of free fatty acids (FFA). Under the enhanced temperature of 7 °C, the lipid resources were used significantly faster than at 0 °C, which could consequently lead to a depletion of this energy reserves before the end of the polar night. On the other hand, the membrane building phospho- and glycolipids remained unchanged during the 8 weeks darkness, indicating still intact thylakoid membranes. These results explain the shorter survival times of polar diatoms with increasing water temperatures during prolonged dark periods.
    Repository Name: EPIC Alfred Wegener Institut
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  • 17
    Publication Date: 2019-08-15
    Description: Chronic, low intensity herbivory by invertebrates, termed background herbivory, has been understudied in tundra, yet its impacts are likely to increase in a warmer Arctic. The magnitude of these changes is however hard to predict as we know little about the drivers of current levels of invertebrate herbivory in tundra. We assessed the intensity of invertebrate herbivory on a common tundra plant, the dwarf birch (Betula glandulosa-nana complex), and investigated its relationship to latitude and climate across the tundra biome. Leaf damage by defoliating, mining and gall-forming invertebrates was measured in samples collected from 192 sites at 56 locations. Our results indicate that invertebrate herbivory is nearly ubiquitous across the tundra biome but occurs at low intensity. On average, invertebrates damaged 11.2% of the leaves and removed 1.4% of total leaf area. The damage was mainly caused by external leaf feeders, and most damaged leaves were only slightly affected (12% leaf area lost). Foliar damage was consistently positively correlated with mid-summer (July) temperature and, to a lesser extent, precipitation in the year of data collection, irrespective of latitude. Our models predict that, on average, foliar losses to invertebrates on dwarf birch are likely to increase by 6–7% over the current levels with a 1 °C increase in summer temperatures. Our results show that invertebrate herbivory on dwarf birch is small in magnitude but given its prevalence and dependence on climatic variables, background invertebrate herbivory should be included in predictions of climate change impacts on tundra ecosystems.
    Repository Name: EPIC Alfred Wegener Institut
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  • 18
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    Springer
    In:  EPIC3Faszination Meeresforschung, Ein ökologisches Lesebuch, Faszination Meeresforschung, Ein ökologisches Lesebuch, Germany, Springer, 8 p., pp. 365-372, ISBN: 978-3-662-49713-5
    Publication Date: 2017-06-06
    Description: Der menschengemachte CO 2-Anstieg und die dadurch verursachte Ozeanversauerung wirken auf alle Meeresorganismen. Bei Tieren kann die Sensitivität gegenüber erhöhten CO 2-Werten sehr unterschiedlich ausfallen und begründet sich vermutlich in der Fähigkeit zur extrazellulären pH-Regulation. Die beobachteten Reaktionen gegenüber Ozeanversauerung reichen von Verhaltensänderungen bei Fischen und verlängerter Entwicklungsdauer bei Krebsen bis hin zur Wachstumsabnahme bei Muscheln und reduzierter Kalkbildung bei Korallen.
    Repository Name: EPIC Alfred Wegener Institut
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  • 19
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Nutrient Cycling in Agroecosystems 108 (2017): 195–209, doi:10.1007/s10705-017-9852-z.
    Description: Meeting food security requirements in sub-Saharan Africa (SSA) will require increasing fertilizer use to improve crop yields, however excess fertilization can cause environmental and public health problems in surface and groundwater. Determining the threshold of reasonable fertilizer application in SSA requires an understanding of flow dynamics and nutrient transport in under-studied, tropical soils experiencing seasonal rainfall. We estimated leaching flux in Yala, Kenya on a maize field that received from 0 to 200 kg ha−1 of nitrogen (N) fertilizer. Soil pore water concentration measurements during two growing seasons were coupled with results from a numerical fluid flow model to calculate the daily flux of nitrate-nitrogen (NO3−-N). Modeled NO3−-N losses to below 200 cm for 1 year ranged from 40 kg N ha−1 year−1 in the 75 kg N ha−1 year−1 treatment to 81 kg N ha−1 year−1 in the 200 kg N ha−1 treatment. The highest soil pore water NO3−-N concentrations and NO3−-N leaching fluxes occurred on the highest N application plots, however there was a poor correlation between N application rate and NO3−-N leaching for the remaining N application rates. The drought in the second study year resulted in higher pore water NO3−-N concentrations, while NO3−-N leaching was disproportionately smaller than the decrease in precipitation. The lack of a strong correlation between NO3−-N leaching and N application rate, and a large decrease in flux between 120 and 200 cm suggest processes that influence NO3−-N retention in soils below 200 cm will ultimately control NO3−-N leaching at the watershed scale.
    Description: Earth Institute, Columbia University; National Science Foundation IIA-0968211; Bill and Melinda Gates Foundation
    Keywords: Leaching ; Nitrogen fertilizer ; Nitrate ; Numerical modeling ; Sub-Saharan Africa
    Repository Name: Woods Hole Open Access Server
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  • 20
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecosystems 20 (2017): 316–330, doi:10.1007/s10021-016-0026-7.
    Description: Sub-arctic birch forests (Betula pubescens Ehrh. ssp. czerepanovii) periodically suffer large-scale defoliation events caused by the caterpillars of the geometrid moths Epirrita autumnata and Operophtera brumata. Despite their obvious influence on ecosystem primary productivity, little is known about how the associated reduction in belowground C allocation affects soil processes. We quantified the soil response following a natural defoliation event in sub-arctic Sweden by measuring soil respiration, nitrogen availability and ectomycorrhizal fungi (EMF) hyphal production and root tip community composition. There was a reduction in soil respiration and an accumulation of soil inorganic N in defoliated plots, symptomatic of a slowdown of soil processes. This coincided with a reduction of EMF hyphal production and a shift in the EMF community to lower autotrophic C-demanding lineages (for example, /russula-lactarius). We show that microbial and nutrient cycling processes shift to a slower, less C-demanding state in response to canopy defoliation. We speculate that, amongst other factors, a reduction in the potential of EMF biomass to immobilise excess mineral nitrogen resulted in its build-up in the soil. These defoliation events are becoming more geographically widespread with climate warming, and could result in a fundamental shift in sub-arctic ecosystem processes and properties. EMF fungi may be important in mediating the response of soil cycles to defoliation and their role merits further investigation.
    Description: This work was supported by NERC (UK Natural Environment Research Council) research Studentship training grant NE/J500434/1.
    Keywords: Defoliation ; Nitrogen ; Carbon ; Birch forest ; Sub-arctic ; Ectomycorrhizal fungi ; Community change
    Repository Name: Woods Hole Open Access Server
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  • 21
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Plant and Soil 414 (2017): 33-51, doi:10.1007/s11104-016-3089-5.
    Description: Hydro-biogeochemical processes in the rhizosphere regulate nutrient and water availability, and thus ecosystem productivity. We hypothesized that two such processes often neglected in rhizosphere models — diel plant water use and competitive cation exchange — could interact to enhance availability of K+ and NH4+, both high-demand nutrients. A rhizosphere model with competitive cation exchange was used to investigate how diel plant water use (i.e., daytime transpiration coupled with no nighttime water use, with nighttime root water release, and with nighttime transpiration) affects competitive ion interactions and availability of K+ and NH4+. Competitive cation exchange enabled low-demand cations that accumulate against roots (Ca2+, Mg2+, Na+) to desorb NH4+ and K+ from soil, generating non-monotonic dissolved concentration profiles (i.e. ‘hotspots’ 0.1–1 cm from the root). Cation accumulation and competitive desorption increased with net root water uptake. Daytime transpiration rate controlled diel variation in NH4+ and K+ aqueous mass, nighttime water use controlled spatial locations of ‘hotspots’, and day-to-night differences in water use controlled diel differences in ‘hotspot’ concentrations. Diel plant water use and competitive cation exchange enhanced NH4+ and K+ availability and influenced rhizosphere concentration dynamics. Demonstrated responses have implications for understanding rhizosphere nutrient cycling and plant nutrient uptake.
    Description: This material is based upon work supported by the U.S. Department of Energy, Office of Science, Office of Biological & Environmental Research Terrestrial Ecosystem Science program under Award Number DE-SC0008182 to Z.G.C. and R.B.N.
    Keywords: Hydraulic redistribution ; Nighttime transpiration ; Plant nutrient uptake ; Reactive-transport ; Rhizosphere ; Root water uptake
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  • 22
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Animal Cognition 20 (2017): 1067–1079, doi:10.1007/s10071-017-1123-5.
    Description: Most mammals can accomplish acoustic recognition of other individuals by means of “voice cues,” whereby characteristics of the vocal tract render vocalizations of an individual uniquely identifiable. However, sound production in dolphins takes place in gas-filled nasal sacs that are affected by pressure changes, potentially resulting in a lack of reliable voice cues. It is well known that bottlenose dolphins learn to produce individually distinctive signature whistles for individual recognition, but it is not known whether they may also use voice cues. To investigate this question, we played back non-signature whistles to wild dolphins during brief capture-release events in Sarasota Bay, Florida. We hypothesized that non-signature whistles, which have varied contours that can be shared among individuals, would be recognizable to dolphins only if they contained voice cues. Following established methodology used in two previous sets of playback experiments, we found that dolphins did not respond differentially to non-signature whistles of close relatives versus known unrelated individuals. In contrast, our previous studies showed that in an identical context, dolphins reacted strongly to hearing the signature whistle or even a synthetic version of the signature whistle of a close relative. Thus, we conclude that dolphins likely do not use voice cues to identify individuals. The low reliability of voice cues and the need for individual recognition were likely strong selective forces in the evolution of vocal learning in dolphins.
    Description: Fieldwork for this study was funded by Harbor Branch Oceanographic Institution, Grossman Family Foundation, Dolphin Quest, Inc., NOAA Fisheries, Disney, the Office of Naval Research, Morris Animal Foundations Betty White Wildlife Rapid Response Fund, the Batchelor Foundation, and the Joint Industry Program.
    Keywords: Dolphin ; Playback experiment ; Non-signature whistle ; Voice cues ; Individual recognition
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  • 23
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ecotoxicology 26 (2017): 820-830, doi:10.1007/s10646-017-1813-4.
    Description: Mathematical models are essential for combining data from multiple sources to quantify population endpoints. This is especially true for species, such as marine mammals, for which data on vital rates are difficult to obtain. Since the effects of an environmental disaster are not fixed, we develop time-varying (nonautonomous) matrix population models that account for the eventual recovery of the environment to the pre-disaster state. We use these models to investigate how lethal and sublethal impacts (in the form of reductions in the survival and fecundity, respectively) affect the population’s recovery process. We explore two scenarios of the environmental recovery process and include the effect of demographic stochasticity. Our results provide insights into the relationship between the magnitude of the disaster, the duration of the disaster, and the probability that the population recovers to pre-disaster levels or a biologically relevant threshold level. To illustrate this modeling methodology, we provide an application to a sperm whale population. This application was motivated by the 2010 Deepwater Horizon oil rig explosion in the Gulf of Mexico that has impacted a wide variety of species populations including oysters, fish, corals, and whales.
    Description: This research is part of the Littoral Acoustic Demonstration Center-Gulf Ecological Monitoring and Modeling (LADC-GEMM) consortium project supported by Gulf of Mexico Research Initiative Year 5–7 Consortia Grants (RFP-IV). Hal Caswell also acknowledges support from ERC Advanced Grant 322989.
    Keywords: Population recovery ; Environmental disasters ; Stochastic modeling ; Lethal impact ; Sublethal impact ; Sperm whales
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  • 24
    Publication Date: 2022-05-25
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Estuaries and Coasts 40 (2017): 22-36, doi:10.1007/s12237-016-0138-5.
    Description: Geomorphology is a fundamental control on ecological and economic function of estuaries. However, relative to open coasts, there has been little quantification of storm-induced bathymetric change in back-barrier estuaries. Vessel-based and airborne bathymetric mapping can cover large areas quickly, but change detection is difficult because measurement errors can be larger than the actual changes over the storm timescale. We quantified storm-induced bathymetric changes at several locations in Chincoteague Bay, Maryland/Virginia, over the August 2014 to July 2015 period using fixed, downward-looking altimeters and numerical modeling. At sand-dominated shoal sites, measurements showed storm-induced changes on the order of 5 cm, with variability related to stress magnitude and wind direction. Numerical modeling indicates that the predominantly northeasterly wind direction in the fall and winter promotes southwest-directed sediment transport, causing erosion of the northern face of sandy shoals; southwesterly winds in the spring and summer lead to the opposite trend. Our results suggest that storm-induced estuarine bathymetric change magnitudes are often smaller than those detectable with methods such as LiDAR. More precise fixed-sensor methods have the ability to elucidate the geomorphic processes responsible for modulating estuarine bathymetry on the event and seasonal timescale, but are limited spatially. Numerical modeling enables interpretation of broad-scale geomorphic processes and can be used to infer the long-term trajectory of estuarine bathymetric change due to episodic events, when informed by fixed-sensor methods.
    Keywords: Bathymetric change ; Sediment transport ; Numerical modeling ; Back-barrier estuary
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  • 25
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Carbon Balance and Management 12 (2017): 10, doi:10.1186/s13021-017-0077-x.
    Description: Determining national carbon stocks is essential in the framework of ongoing climate change mitigation actions. Presently, assessment of carbon stocks in the context of greenhouse gas (GHG)-reporting on a nation-by-nation basis focuses on the terrestrial realm, i.e., carbon held in living plant biomass and soils, and on potential changes in these stocks in response to anthropogenic activities. However, while the ocean and underlying sediments store substantial quantities of carbon, this pool is presently not considered in the context of national inventories. The ongoing disturbances to both terrestrial and marine ecosystems as a consequence of food production, pollution, climate change and other factors, as well as alteration of linkages and C-exchange between continental and oceanic realms, highlight the need for a better understanding of the quantity and vulnerability of carbon stocks in both systems. We present a preliminary comparison of the stocks of organic carbon held in continental margin sediments within the Exclusive Economic Zone of maritime nations with those in their soils. Our study focuses on Namibia, where there is a wealth of marine sediment data, and draws comparisons with sediment data from two other countries with different characteristics, which are Pakistan and the United Kingdom. Results indicate that marine sediment carbon stocks in maritime nations can be similar in magnitude to those of soils. Therefore, if human activities in these areas are managed, carbon stocks in the oceanic realm—particularly over continental margins—could be considered as part of national GHG inventories. This study shows that marine sediment organic carbon stocks can be equal in size or exceed terrestrial carbon stocks of maritime nations. This provides motivation both for improved assessment of sedimentary carbon inventories and for reevaluation of the way that carbon stocks are assessed and valued. The latter carries potential implications for the management of human activities on coastal environments and for their GHG inventories.
    Description: We acknowledge research support from ETH Zurich and the Swiss National Science Foundation.
    Keywords: Carbon stocks ; Sediments ; Oceans ; Climate change ; Exclusive Economic Zone ; Carbon inventory
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  • 26
    Publication Date: 2022-05-25
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Earth, Planets and Space 69 (2017): 138, doi:10.1186/s40623-017-0724-1.
    Description: Despite strong anisotropy seen in analysis of seismic data from the NoMelt experiment in 70 Ma Pacific seafloor, a previous analysis of coincident magnetotelluric (MT) data showed no evidence for anisotropy in the electrical conductivity structure of either lithosphere or asthenosphere. We revisit the MT data and use 1D anisotropic models of the lithosphere to demonstrate the limits of acceptable anisotropy within the data. We construct 1D models by varying the thickness and the degree of anisotropy within the lithosphere and conduct a series of tests to investigate what types of electrical anisotropy are compatible with the data. We find that electrical anisotropy is possible in a sheared and/or hydrous mantle within the lower lithosphere (60–90 km depth). The data are not compatible with pervasive electrical anisotropy in the crust. Causes of anisotropy within the highly resistive upper and mid-lithosphere, as seen seismically, are not expected to cause measurable impacts on MT response.
    Description: RLE was supported by NSF Grant OCE-0928663.
    Keywords: Electrical anisotropy ; Oceanic lithosphere ; Shearing ; Water ; Central Pacific
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  • 27
    Publication Date: 2022-05-24
    Description: In this study, we attempt to improve the standards in Probabilistic Seismic Hazard Assessment (PSHA) towards a time-dependent hazard assessment by using the most advanced methods and new databases for the Calabria region, Italy. In this perspective we improve the knowledge of the seismotectonic framework of the Calabrian region using geologic, tectonic, paleoseismological, and macroseismic information available in the literature. We built up a PSHA model based on the long-term recurrence behavior of seismogenic faults, together with the spatial distribution of historical earthquakes. We derive the characteristic earthquake model for those sources capable of rupturing the entire fault segment (full-rupture) independently with a single event of maximum magnitude. We apply the floating rupture model to those earthquakes whose location is not known sufficiently constrained. We thus associate these events with longer fault systems, assuming that any such earthquake can rupture anywhere within the particular fault system (floating partial-rupture) with uniform probability. We use a Brownian Passage Time (BPT) model characterized by mean recurrence, aperiodicity, or uncertainty in the recurrence distribution and elapsed time since the last characteristic earthquake. The purpose of this BPT model is to express the time-dependence of the seismic processes to predict the future ground motions in the region. Besides, we consider the influence on the probability of earthquake occurrence controlled by the change in static Coulomb stress (ΔCFF) due to fault interaction; to pursue this, we adopt a model built on the fusion of BPT model (BPT + ΔCFF). We present our results for both time-dependent (renewal) and time-independent (Poisson) models in terms of Peak Ground Acceleration (PGA) maps for 10% probability of exceedance in 50 years. The hazard may increase by more than 20% or decrease by as much as 50% depending on the different occurrence model. Seismic hazard in terms of PGA decreases about 20% in the Messina Strait, where a recent major earthquake took place, with respect to traditional time-independent estimates. PGA near the city of Cosenza reaches ~ 0.36 g for the time-independent model and 0.40 g for the case of the time-dependent one (i.e. a 15% increase). Both the time-dependent and time-independent models for the period of 2015–2065 demonstrate that the city of Cosenza and surrounding areas bear the highest seismic hazard in Calabria.
    Description: Published
    Description: 2497–2524
    Description: 5T. Modelli di pericolosità sismica e da maremoto
    Description: JCR Journal
    Keywords: Probabilistic seismic hazard maps ; Time-dependent hazard ; Fault-based model ; Fault interaction ; Seismogenic sources ; Calabria-Italy ; 04.07. Tectonophysics ; 04.06. Seismology ; 05.08. Risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 28
    Publication Date: 2022-05-26
    Description: This paper is not subject to U.S. copyright. The definitive version was published in Marine Biology 164 (2017): 181, doi:10.1007/s00227-017-3211-0.
    Description: Understanding population dynamics in broadly distributed marine species with cryptic life history stages is challenging. Information on the population dynamics of sea turtles tends to be biased toward females, due to their accessibility for study on nesting beaches. Males are encountered only at sea; there is little information about their migratory routes, residence areas, foraging zones, and population boundaries. In particular, male leatherbacks (Dermochelys coriacea) are quite elusive; little is known about adult and juvenile male distribution or behavior. The at-sea distribution of male turtles from different breeding populations is not known. Here, 122 captured or stranded male leatherback turtles from the USA, Turkey, France, and Canada (collected 1997–2012) were assigned to one of nine Atlantic basin populations using genetic analysis with microsatellite DNA markers. We found that all turtles originated from western Atlantic nesting beaches (Trinidad 55%, French Guiana 31%, and Costa Rica 14%). Although genetic data for other Atlantic nesting populations were represented in the assignment analysis (St. Croix, Brazil, Florida, and Africa (west and south), none of the male leatherbacks included in this study were shown to originate from these populations. This was an unexpected result based on estimated source population sizes. One stranded turtle from Turkey was assigned to French Guiana, while others that were stranded in France were from Trinidad or French Guiana breeding populations. For 12 male leatherbacks in our dataset, natal origins determined from the genetic assignment tests were compared to published satellite and flipper tag information to provide evidence of natal homing for male leatherbacks, which corroborated our genetic findings. Our focused study on male leatherback natal origins provides information not previously known for this cryptic, but essential component of the breeding population. This method should provide a guideline for future studies, with the ultimate goal of improving management and conservation strategies for threatened and endangered species by taking the male component of the breeding population into account.
    Description: Sample collection in Nova Scotia, Canada, was supported by funding from Canadian Wildlife Federation, Environment Canada, Fisheries and Oceans Canada, George Cedric Metcalf Foundation, Habitat Stewardship Program for Species at Risk, National Fish and Wildlife Foundation (USA), National Marine Fisheries Service (USA), Natural Sciences and Engineering Research Council of Canada, and World Wildlife Fund Canada. Funding for US samples was provided by National Oceanic and Atmospheric Administration, Massachusetts Division of Marine Fisheries, National Fish and Wildlife Foundation, and Cape Cod Commercial Fisherman’s Alliance. Funding support for this analysis and for Kelly R. Stewart was provided by a Lenfest Ocean Program Grant.
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  • 29
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Surveys in Geophysics 38 (2017): 1529–1568, doi:10.1007/s10712-017-9428-0.
    Description: Trade-wind cumuli constitute the cloud type with the highest frequency of occurrence on Earth, and it has been shown that their sensitivity to changing environmental conditions will critically influence the magnitude and pace of future global warming. Research over the last decade has pointed out the importance of the interplay between clouds, convection and circulation in controling this sensitivity. Numerical models represent this interplay in diverse ways, which translates into different responses of trade-cumuli to climate perturbations. Climate models predict that the area covered by shallow cumuli at cloud base is very sensitive to changes in environmental conditions, while process models suggest the opposite. To understand and resolve this contradiction, we propose to organize a field campaign aimed at quantifying the physical properties of trade-cumuli (e.g., cloud fraction and water content) as a function of the large-scale environment. Beyond a better understanding of clouds-circulation coupling processes, the campaign will provide a reference data set that may be used as a benchmark for advancing the modelling and the satellite remote sensing of clouds and circulation. It will also be an opportunity for complementary investigations such as evaluating model convective parameterizations or studying the role of ocean mesoscale eddies in air–sea interactions and convective organization.
    Description: The EUREC4A project is supported by the European Research Council (ERC), under the European Union’s Horizon 2020 research and innovation programme (Grant Agreement No. 694768), by the Max Planck Society and by DFG (Deutsche Forschungsgemeinschaft, German Research Foundation) Priority Program SPP 1294.
    Keywords: Trade-wind cumulus ; Shallow convection ; Cloud feedback ; Atmospheric circulation ; Field campaign
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  • 30
    Publication Date: 2022-05-26
    Description: © The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Evolutionary Biology 44 (2017): 5-10, doi:10.1007/s11692-016-9385-4.
    Description: The evolution of senescence is often explained by arguing that, in nature, few individuals survive to be old and hence it is evolutionarily unimportant what happens to organisms when they are old. A corollary to this idea is that extrinsically imposed mortality, because it reduces the chance of surviving to be old, favors the evolution of senescence. We show that these ideas, although widespread, are incorrect. Selection leading to senescence does not depend directly on survival to old age, but on the shape of the stable age distribution, and we discuss the implications of this important distinction. We show that the selection gradient on mortality declines with age even in the hypothetical case of zero mortality, when survivorship does not decline. Changing the survivorship function by imposing age independent mortality has no affect on the selection gradients. A similar result exists for optimization models: age independent mortality does not change the optimal result. We propose an alternative, brief explanation for the decline of selection gradients, and hence the evolution of senescence.
    Description: HC acknowledges financial support from ERC Advanced Grant 322989, NSF Grants DEB-1145017 and DEB-1257545, and the Alexander von Humboldt Foundation.
    Keywords: Extrinsic mortality ; Survivorship ; Age distribution ; Selection gradient ; Senescence
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  • 31
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Current Biology 27 (2017): 854–859, doi:10.1016/j.cub.2017.01.050.
    Description: Our visual system allows us to rapidly identify and intercept a moving object. When this object is far away, we base the trajectory on the target’s location relative to an external frame of reference [1]. This process forms the basis for the constant bearing angle (CBA) model, a reactive strategy that ensures interception since the bearing angle, formed between the line joining pursuer and target (called the range vector) and an external reference line, is held constant [2; 3 ; 4]. The CBA model may be a fundamental and widespread strategy, as it is also known to explain the interception trajectories of bats and fish [5 ; 6]. Here, we show that the aerial attack of the tiny robber fly Holcocephala fusca is consistent with the CBA model. In addition, Holcocephala fusca displays a novel proactive strategy, termed “lock-on” phase, embedded with the later part of the flight. We found the object detection threshold for this species to be 0.13°, enabled by an extremely specialized, forward pointing fovea (∼5 ommatidia wide, interommatidial angle Δφ = 0.28°, photoreceptor acceptance angle Δρ = 0.27°). This study furthers our understanding of the accurate performance that a miniature brain can achieve in highly demanding sensorimotor tasks and suggests the presence of equivalent mechanisms for target interception across a wide range of taxa.
    Description: This work was funded by the Air Force Office of Scientific Research (FA9550-15-1-0188 to P.T.G.-B. and K.N. and FA9550-15-1-0068 to D.G.S.), an Isaac Newton Trust/Wellcome Trust ISSF/University of Cambridge Joint Research Grant (097814/Z/11/Z) to P.T.G.-B., a Biotechnology and Biological Sciences Research Council David Phillips Fellowship (BBSRC, BB/L024667/1) to T.J.W., a Royal Society International Exchange Scheme grant to P.T.G.-B. (75166), a Swedish Research Council grant (2012-4740) to K.N., and a Shared Equipment Grant from the School of Biological Sciences (University of Cambridge, RG70368).
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  • 32
    Publication Date: 2022-05-26
    Description: © The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Ambio 46, Supple. 1 (2017): 160-173, doi:10.1007/s13280-016-0870-x.
    Description: Long-term measurements of ecological effects of warming are often not statistically significant because of annual variability or signal noise. These are reduced in indicators that filter or reduce the noise around the signal and allow effects of climate warming to emerge. In this way, certain indicators act as medium pass filters integrating the signal over years-to-decades. In the Alaskan Arctic, the 25-year record of warming of air temperature revealed no significant trend, yet environmental and ecological changes prove that warming is affecting the ecosystem. The useful indicators are deep permafrost temperatures, vegetation and shrub biomass, satellite measures of canopy reflectance (NDVI), and chemical measures of soil weathering. In contrast, the 18-year record in the Greenland Arctic revealed an extremely high summer air-warming of 1.3°C/decade; the cover of some plant species increased while the cover of others decreased. Useful indicators of change are NDVI and the active layer thickness.
    Description: The Toolik research was supported in part by NSF Grants DEB 0207150, DEB 1026843, ARC 1107701, and ARC 1504006.
    Keywords: Alaska Toolik ; Climate change ; Ecological effects ; Greenland Zackenberg ; Medium pass filter ; Vegetation
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  • 33
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    In:  EPIC3Springer, 339 p., ISBN: 0044-7447
    Publication Date: 2023-06-21
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    In:  EPIC3Faszination Meeresforschung: Ein ökologisches Lesebuch, Faszination Meeresforschung: Ein ökologisches Lesebuch, Springer, pp. 211-222
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    In:  EPIC3Faszination Meeresforschung, Springer, pp. 135-141, ISBN: 978-3-662-49714-2
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    In:  EPIC3Building Bridges at the Science-Stakeholder Interface: Towards Knowledge Exchange in Earth System Science, SpringerBriefs in Earth System Sciences, Cham, Springer, 7 p., pp. 85-91, ISBN: 978-3-319-75919-7
    Publication Date: 2023-06-21
    Description: Anthropogenic litter contamination of the oceans is a global problem of growing concern and currently receives strongly increasing attention by policy makers, public authorities, media and the general public. Unlike many other pollutants, marine litter on beaches and its deleterious effects on marine mammals, birds and turtles have attracted much attention as they can be directly observed by stakeholders.
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    In:  EPIC3Faszination Meeresforschung – ein ökologisches Lesebuch, Faszination Meeresforschung – ein ökologisches Lesebuch, Springer, 4 p., pp. 380-384, ISBN: 978-3-662-49713-5
    Publication Date: 2023-06-21
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  • 38
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    Publication Date: 2020-02-12
    Keywords: 550 - Earth sciences
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    Publication Date: 2020-02-12
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  • 40
    ISSN: 1434-6052
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. A system of linear homogeneous algebraic equations for the coupling constant ratios of vector mesons to hadrons is derived by imposing the assumed asymptotic behavior upon the VMD pole parameterization of an hadron electromagnetic form factor. A similar system of equations with a simpler structure of the coefficients, taken as even powers of the vector-meson masses, is derived by means of integral superconvergent sum rules for the imaginary part of the considered form factor using its appropriate $\delta$ -function approximation. Although both systems have been derived starting from different properties of the electromagnetic form factor and they each have their own appearances, it is shown explicitly that they are fully equivalent.
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  • 41
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    The European physical journal 28 (2003), S. 55-61 
    ISSN: 1434-6052
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    Topics: Physics
    Notes: Abstract. We investigate a flexible method by which we can test the unitarity of the quark flavor-mixing matrix step by step. Singular-value-decomposition (SVD) techniques are used in analyzing the mixing matrix over a broader parameter region than the unitarity region. Unitary constraints let us extract CP-violating properties without any specific parameterization when the magnitudes of at least three mixing-matrix elements in three-generation quark mixing are given. This method can al so be applied to the analysis of lepton flavor mixing, in which only a few moduli are presently measured.
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  • 42
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    The European physical journal 28 (2003), S. 133-143 
    ISSN: 1434-6052
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    Topics: Physics
    Notes: Abstract. The status of the evaluation of the MSSM Higgs sector is reviewed. The phenomenological impact of recently obtained corrections is discussed. In particular it is shown that the upper bound on mh within the MSSM is shifted upwards. Consequently, lower limits on $\tan\beta$ obtained by confronting the upper bound as function of $\tan\beta$ with the lower bound on mh from Higgs searches are significantly weakened. Furthermore, th e region in the MA- $\tan\beta$ -plane where the coupling of the lightest Higgs boson to down-type fermions is suppressed is modified. The presently not calculated higher-order corrections to the Higgs-boson mass matrix are estimated to shift the mass of the lightest Higgs boson by up to 3 GeV.
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  • 43
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    The European physical journal 28 (2003), S. 71-77 
    ISSN: 1434-6052
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    Topics: Physics
    Notes: Abstract. The contribution of the QCD pomeron to the process $AA \rightarrow AA J/\Psi J/\Psi $ is discussed. We focus on the photon-photon collision, with the quasi-real photon coming from the Weizsäcker-Williams spectrum of the nuclei. We calculate the cross section for this process considering the solution of the LLA BFKL equation at zero momentum transfer using a small t approximation for the differential cross section of the subprocess. Furthermore, the impa ct of non-leading corrections to the BFKL equation is also analyzed. In both cases the cross section is found to increase with the energy, predicting considerable values for the LHC energies. Moreover, we compare our results with the Born two-gluon approximation, which is energy independent at the photon level. Our results indicate that the experimental analyses of this process can be useful to discriminate the QCD dynamics at high energies.
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  • 44
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    The European physical journal 28 (2003), S. 147-150 
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    Topics: Physics
    Notes: Abstract. The method of Abelian decomposition proposed by Faddeev and Niemi is used to derive the low-energy effective lagrangian of G2 gauge theory. The G2 algebra is studied. The commutation relations among the generators of the G2 algebra are established, based on the framework of its regular maximal subalgebra, an SU(3) algebra.
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  • 45
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    The European physical journal 28 (2003), S. 15-26 
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    Notes: Abstract. Searches for resonant $\tilde\nu$ production in e + e - collisions under the assumption that R-parity is not conserved and that the dominant R-parity violating coupling is $\lambda_{121}$ or $\lambda_{131}$ used data recorded by DELPHI in 1997 to 2000 at centre-of-mass energies of 183 to 208 GeV. No deviation from the Standard Model was observed. Upper limits are given for the $\lambda_{121}$ and $\lambda_{131}$ couplings as a function of the sneutrino mass and total width. The limits are especially stringent for sneutrino masses equal to the centre-of-mass energies with the highest integrated luminosities recorded.
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    The European physical journal 28 (2003), S. 97-105 
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    Notes: Abstract. We present an extension to $\pi^{\pm} p$ and $K^{\pm} p$ elastic scattering at high energies of the impact-picture phenomenology we first proposed more than twenty years ago, for p p and $\bar p p$ elastic scattering. We show, in particular, that the analytic form of the opacity function for the proton obtained previously is compatible with the experimental results on $\pi p$ and K p elastic s cattering at high energies. It is proposed that $\pi^{\pm}$ and $K^{\pm}$ external beams be provided from CERN-LHC, so that their elastic scattering from protons can be studied at higher energies. Our phenomenology for p p and $\bar p p$ elastic scattering is updated by including new data and we give predictions for future experiments at BNL-RHIC and CERN-LHC.
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    The European physical journal 28 (2003), S. 151-154 
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    Notes: Abstract. The generalization of QCD motivated classical SU(2) Yang-Mills theory coupled to a scalar field is discussed. The massive scalar field, corresponding to the scalar glueball, provides a confining potential for static, point-like, external sources. In the case of a massless scalar field screening solutions are found. However, there is a confining sector as well. Both, massive and massless confining solutions, are compared with phenomenological potentials. The case of a non-dynam ical permittivity is also discussed.
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    The European physical journal 28 (2003), S. 119-122 
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    Notes: Abstract. We propose a simple Glauber-type mechanism for the suppression of jet production up to transverse momenta of about 10 $\mathrm {GeV}/c$ at RHIC. For processes in this kinematic region, the formation time is smaller than the interval between two successive hard partonic collisions and the subsequent collision influences the jet production. The number of jets then roughly scales with the number of participants. Proportionality to the number of binary collisions is reco vered for very high transverse momenta. The model predicts suppression of jet production in $d + {\mathrm {Au}}$ collisions at RHIC.
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    The European physical journal 28 (2003), S. 63-69 
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    Notes: Abstract. The first observation of the $\bar{B}^0_d\rightarrow D^0\bar{K}^0$ and $\bar{B}^0_d\rightarrow D^0\bar{K}^{*0}$ transitions by the Belle Collaboration allows us to do a complete isospin analysis of the $B\rightarrow DK^{(*)}$ decay modes. We find that their respective isospin phase shifts are very likely to lie in the ranges $37^\circ \leq (\phi_1 -\phi_0)_{DK} \leq 63^\circ$ (or around $50^\circ$ ) and $25^\circ \leq (\phi_1 -\phi_0)_{DK^*} \leq 50^\circ$ (or around $35^\circ$ ), although the possibility $(\phi_1 -\phi_0)_{DK} = (\phi_1 -\phi_0)_{DK^*} = 0^\circ$ cannot be ruled out at present. Thus significant final-state rescattering effects possibly exist in such exclusive $\vert\Delta B\vert = \vert\Delta C\vert = \vert\Delta S\vert =1$ processes. We determine the spectator and color-suppressed spectator quark-diagram amplitudes of the $B\rightarrow DK$ and $B\rightarrow DK^*$ decays, and compare them with the corresponding quark-diagram amplitudes of the $B\rightarrow D\pi$ and $B\rightarrow D\rho$ decays. The effects of SU(3) flavor symmetry breaking are in most cases understandable in the factorization approximation, which works for the individual isospin amplitudes. Very instructive predictions are also obtained for the branching fractions of rare $\bar{B}^0_d \rightarrow \bar{D}^0 \bar{K}^{(*)0}$ , $B^-_u \rightarrow \bar{D}^0 K^{(*)-}$ and $B^-_u \rightarrow D^- \bar{K}^{(*)0}$ transitions.
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    The European physical journal 28 (2003), S. 145-146 
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    Notes: Abstract. The possibility that higher dimensional field theories are broken spontaneously, through the usual Nambu-Goldstone mechanism, to 4-dimension is explored. As a consequence, vector Goldstone bosons can arise in this breaking of Lorentzian symmetry from higher dimension to 4-dimension. This can provide a simple mechanism for reduction to 4-dimension in theories with extra dimensions.
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    The European physical journal 28 (2003), S. 45-54 
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    Notes: Abstract. The exclusive production of proton-antiproton pairs in the collisions of two quasi-real photons has been studied using data taken at $\sqrt{s_{ee}} = 183 $ GeV and 189 GeV with the OPAL detector at LEP. Results are presented for $p\bar{p}$ invariant masses, W, in the range 2.15〈W〈3.95 GeV. The cross-section measurements are compared with previous data and with recent analytic calculations based on t he quark-diquark model.
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    The European physical journal 28 (2003), S. 1-13 
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    Notes: Abstract. Events containing only energetic photons are analysed in a sample of $628 \mathrm{pb}^{-1}$ of data recorded from $\rm e^+e^-$ collisions at centre-of-mass energies between 189 and 209 GeV by the ALEPH detector at LEP. The $e^+ e^-\to \nu\bar{\nu}\gamma(\gamma)$ and $e^+ e^-\to \gamma\gamma(\gamma)$ cross sections are measured and found to be in agreement with the standard model predictions. The number of light neutrino generations is determined to be $N_\nu = 2.86 \pm 0.09$ . Upper limits are derived on the cross sections for photon production in the context of several supersymmetric models. Limits are also set on the parameters of models with extra spatial dimensions, with contact interactions and with excited electrons.
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  • 53
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    Notes: Abstract. We present the machine parameters and physics capabilities of the CLIC Higgs Experiment (CLICHE), a low-energy $\gamma \gamma$ collider based on CLIC 1, the demonstration project for the higher-energy two-beam accelerator CLIC. CLICHE is conceived as a factory capable of producing around 20,000 light Higgs bosons per year. We discuss the requirements for the CLIC 1 beams and a laser backscattering system capable of producing a $\gamma \gamma$ total (peak) luminosity of $2.0 (0.36) \times 10^{34}$ cm-2s-1 with $E_{CM}(\gamma \gamma) \sim 115$ GeV. We show how CLICHE could be used to measure accurately the mass, $\bar b b$ , WW and $\gamma \gamma$ decays of a light Higgs boson. We illustrate how these measurements may distinguish between the Standard Model Higgs boson and those in supersymmetric and more general two-Higgs-doublet models, complement ing the measurements to be made with other accelerators. We also comment on other prospects in $\gamma \gamma$ and $e^- \gamma$ physics with CLICHE.
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    The European physical journal 28 (2003), S. 79-95 
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    Notes: Abstract. A knowledge of the radial distributions of quarks inside hadrons could lead to a better understanding of the QCD description of these hadrons and possibly suggest forms for phenomenological models. As a step in this direction, in an earlier work, the charge (vector) and matter (scalar) radial distributions of heavy-light mesons were measured in the quenched approximation on a $16^3\times 24$ lattice with a lattice spacing of $a\approx 0.17$ fm, and a hopping parameter corresponding to a light quark mass about that of the strange quark. Here several improvements are now made: 1) The configurations are generated using dynamical fermions with $a\approx 0.14$ fm; 2) Many more gauge configurations are included; 3) The distributions at many off-axis, in addition to on-axis, points are measured; 4) The data analysis is much more complete. In particular, distributions involving excited states are extracted. The exponential decay of the cha rge and matter distributions can be described by mesons of mass 0.9 $\pm 0.1$ and 1.5 $\pm 0.1$ GeV respectively - values that are consistent with those of vector and scalar $q\bar{q}$ -states calculated directly with the same lattice parameters.
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    The European physical journal 28 (2003), S. 123-131 
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    Notes: Abstract. We show that maximal atmospheric and large solar neutrino mixing can be implemented in SU(5) gauge theories, by making use of the U(1) F symmetry associated with a suitably defined family number F, together with a Z2 symmetry which does not commute with F. U(1) F is softly broken by the mass terms of the right-handed neutrino singlets, which are responsible for the seesaw mechanism; in additio n, U(1) F is also spontaneously broken at the electroweak scale. In our scenario, lepton mixing stems exclusively from the right-handed-neutrino Majorana mass matrix, whereas the CKM matrix originates solely in the up-type-quark sector. We show that, despite the non-supersymmetric character of our model, unification of the gauge couplings can be achieved at a scale 1016 GeV 〈 m U 〈 1019 GeV; indeed, we have found a particula r solution to this problem which yields results almost identical to the ones of the minimal supersymmetric standard model.
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    The European physical journal 28 (2003), S. 203-209 
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    Notes: Abstract. The possibility to effectively exploit the directionality of the measured counting rate as a signature for WIMPs by using anisotropic scintillators is revisited and discussed in some details.
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    The European physical journal 28 (2003), S. 107-114 
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    Notes: Abstract. Using the pole approach we determine the mass and width of the f 0 (980); in particular, we analyze the possibility that two nearby poles are associated to it. We restrict our analysis to a neighborhood of the resonance, using $\pi\pi$ data for the phase shift and inelasticity, and the invariant mass spectrum of the $J/\psi\rightarrow\phi\pi\pi, \phi K\bar K$ decays. The formalism we use is based on unitarity and a generalized ver sion of the Breit-Wigner parameterization. We find that a single pole describes the f 0 (980), the precise position depending upon the $\pi\pi$ data used. As a byproduct, values for the $g_{f_0\pi\pi}$ and $g_{f_0K\bar K}$ coupling constants are obtained.
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    The European physical journal 28 (2003), S. 211-221 
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    Notes: Abstract. We analytically derive the transition probabilities for four-neutrino oscillations in matter. The time-evolution operator giving the neutrino oscillations is expressed by a finite sum of terms up to the third power of the Hamiltonian in a matrix form, using the Cayley-Hamilton theorem. The result of the computation for the probabilities in some mass patterns tells us that it is actually difficult to observe the resonance between one of the three active neutrinos and the fourth (sterile) neutrino near the earth, even if the fourth neutrino exists.
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    The European physical journal 28 (2003), S. 223-236 
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    Notes: Abstract. We consider the two-Higgs-doublet model with explicit CP-violation, where the effective Higgs potential is not CP-invariant at the tree level. The three neutral Higgs bosons of the model are the mixtures of CP-even and CP-odd bosons which exist in the CP-conserving limit of the theory. The mass spectrum and tree-level couplings of the neutral Higgs bosons to gauge bosons and fermions are significantly dependent on the parameters of the Higgs boson mixing matrix. We calculate the Higgs-gauge boson, Higgs-fermion, triple and quartic Higgs self-interactions in the MSSM with explicit CP-violation in the Higgs sector and CP-violating Yukawa interactions of the third generation scalar quarks. In some regions of the MSSM parameter space substantial changes of the self-interaction vertices take place, leading to significant suppression or enhancement of the multiple Higgs boson production cross sections.
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    The European physical journal 28 (2003), S. 261-278 
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    Notes: Abstract. Final state radiation (FSR) in pion pair production cannot be calculated reliably because of the composite structure of the pions. However, FSR corrections have to be taken into account for a precise evaluation of the hadronic contribution to g-2 of the muon. The role of FSR in both energy scan and radiative return experiments is discussed. It is shown how FSR influences the pion form factor extraction from experimental data and, as a consequence, the evaluation of $a_{\mu}^{had}$ . In fact the $O(\alpha)$ FSR corrections should be included to reach the precision we are aiming at. We argue that for an extraction of the desired FSR-inclusive cross section $\sigma^{(\gamma)}_{had}$ a photon-inclusive scan measurement of the ” $e^+e^- \to \pi^+\pi^- + {photons}$ ” cross section is needed. For exclusive scan and radiative return measurements in contrast we have to rely on ad hoc FSR models if we want to obtain either $\sigma^{(\gamma)}_{had}$ or the FSR-exclusive cross section $\sigma^{(0)}_{had}$ . We thus advocate to consider seriously precise photon-inclusive energy scan measurements at present and future low energy e + e - -facilities. Then together with radiative return measurements from DA $\Phi$ NE and BABAR and forthcoming scan measurements at VEPP-2000 we have a good chance to substantially improve the evaluation of $a_{\mu}^{had}$ in the future.
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    The European physical journal 28 (2003), S. 237-241 
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    Notes: Abstract. In the framework of factorization and the heavy quark effective theory, $B\to D_2^*\pi$ modes are analyzed. We adopt the result from the QCD sum rule calculation for the hadronic matrix elements at leading order of $\Lambda_{\mathrm{QCD}}/m_Q$ and $\alpha_{\mathrm{s}}$ . The QCD sum rule results are well compatible with the current data, with the prediction for the branching ratios $\mathcal{B}({\bar B}^0\to D_2^{*+}\pi^-) = 8.94\times 10^{-4}$ and $\mathcal{B}(B^-\to D_2^{*0}\pi^-) = 9.53\times 10^{-4}$ for $N_C^{\mathrm{eff}} = 2$ . We give constraints on the interception $\tau(1)$ and the slope parameter $\rho^2$ of the leading Isgur-Wise function from the experimental bounds. It is argued that the observation of non-zero $\mathcal{B}({\bar B}^0\to D_2^{*0}\pi^0)$ directly measures the non-factorizable effects.
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    The European physical journal 28 (2003), S. 279-295 
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    Notes: Abstract. We analyze the energy-momentum properties of relativistic short-lived particles with the result that they are characterized by two 4-vectors: in addition to the familiar energy-momentum vector (timelike) there is an energy-momentum `spread vector' (spacelike). The wave functions in space and time for unstable particles are constructed. For the relativistic properties of unstable states we refer to Wigner's method of Poincaré group representations that are induced by representations of the space-time translation and rotation groups. If stable particles, unstable particles and resonances are treated as elementary objects that are not fundamentally different one has to take into account that they will not generally be orthogonal to each other in their state space. The scalar product between a stable and an unstable state with otherwise identical properties is calculated in a particular Lorentz frame. The spin of an unstable particle is not infinitely sharp but has a `spin spread' giving rise to `spin neighbors'. This opens the possibility of a non-zero scalar product between states with unequal spin. - A first practical application of non-orthogonal states is seen in diffraction dissociation reactions whose large cross-sections are attributed to interference of states that are `partially identical'.
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    The European physical journal 28 (2003), S. 175-201 
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    Notes: Abstract. Cross sections for e-p neutral current deep inelastic scattering have been measured at a centre-of-mass energy of 318 GeV using an integrated luminosity of 15.9 pb-1 collected with the ZEUS detector at HERA. Results on the double-differential cross-section $d^2\sigma / dx dQ^2$ in the range 185 〈 Q 2 〈 50 000 GeV2 and 0.0037 〈 x 〈 0.75, as well as the single-differential cross-sections $d\sigma / dQ^2$ , $d\sigma / dx$ and $d\sigma / dy$ for Q 2 〉 200 GeV2, are presented. To study the effect of Z-boson exchange, $d\sigma / dx$ has also been measured for Q 2 〉 10 000 GeV2. The structure function xF3 has been extracted by combining the e-p results presented here with the recent ZEUS measurements of e+p neutral current deep inelastic scattering. All results agree well with the predictions of the Standard Model.
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    The European physical journal 28 (2003), S. 243-248 
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    Notes: Abstract. We study the differential branching ratio, the branching ratio and the CP-violating asymmetry for the exclusive $B_{d}\to (\eta,\eta^{'})\ell^+\ell^-$ decays in the standard model. We deduce the $B_{d}\to (\eta, \eta^{{'}})$ form factors from the form factors of $B \to \pi$ available in the literature, by using the SU(3) F symmetry. We observe that these decay modes, which are within the reach of forthcoming B-factories, are very promising for observing CP-violation.
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    The European physical journal 28 (2003), S. 249-259 
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    Notes: Abstract. We study baryon pair production in two-photon collisions, $\gamma \gamma \rightarrow B \bar{B}$ , within perturbative quantum chromodynamics, treating baryons as quark-diquark systems. We extend previous work within the same approach by treating constituent-mass effects systematically by means of an expansion in the small parameter (mass/photon energy). Our approach enables us to give a consistent description of the cross sections for all octet baryon channels. Adopting the model parameters from foregoing work, we are able to reproduce the most recent large-momentum-transfer data from LEP for the $p\bar{p}$ , $\Lambda\bar{\Lambda}$ , and $\Sigma^0\bar{\Sigma}^0$ channels in a quite satisfactory way. We also briefly address the crossed process for the proton channel, $\gamma p \rightarrow \gamma p$ .
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  • 66
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    Notes: Abstract. Neutral B meson oscillations in the $B^0_s-\overline{B^0_s}$ and $B^0_d-\overline{B^0_d}$ systems were studied using a sample of about 4.0 million hadronic Z decays recorded by the DELPHI detector between 1992 and 2000. Events with a high transverse momentum lepton were removed and a sample of 770 k events with an inclusively reconstructed vertex was selected. The mass difference between the two physical states in the $B^0_d-\overline{B^0_d}$ system was measured to be: \Delta m_d = (0.531 \pm 0.025 (stat.) \pm 0.007 (syst.)) \rm ps^{-1}. The following limit on the width difference of these states was also obtained: \vert\Delta\Gamma_{B_d}\vert / \Gamma_{B_d} 〈 0.18\ \ at \ \ 95\%\ \ CL. As no evidence for $B^0_s-\overline{B^0_s}$ oscillations was found, a limit on the mass difference of the two physical states was given: \Delta m_s 〉 5.0 \: \rm ps^{-1} \ \ at \ \ 95\%\ \ CL. The corresponding sensitivity of this analysis is equal to 6.6 ps-1.
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    The European physical journal 28 (2003), S. 305-312 
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    Notes: Abstract. The rare decays $B^0 \to D_s^- K^+$ and $B^+ \to D_s^+ \overline{K}^0$ can occur only via annihilation type diagrams in the standard model. We calculate these decays in the perturbative QCD approach. We found that the calculated branching ratio of $B^0 \to D_s^- K^+$ agreed with the data which had been observed in the KEK and SLAC B factories. The decay $B^+ \to D_s^+ \overline{K}^0$ has a very small branching ratio at $\cal O(10^{-8})$ , due to the suppression from the CKM matrix elements |V ub * V cd |.
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    The European physical journal 28 (2003), S. 389-393 
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    Notes: Abstract. In the q-deformed theory the perturbation approach can be expressed in terms of two pairs of undeformed position and momentum operators. There are two configuration spaces. Correspondingly there are two q-perturbation Hamiltonians; one originates from the perturbation expansion of the potential in one configuration space, the other one originates from the perturbation expansion of the kinetic energy in another configuration space. In order to establish a general foundation of the q-perturbation theory, two perturbation equivalence theorems are proved. The first is Equivalence Theorem I: Perturbation expressions of the q-deformed uncertainty relations calculated by two pairs of undeformed operators are the same, and the two q-deformed uncertainty relations undercut Heisenberg's minimal one in the same style. The general Equivalence Theorem II is: for any potential (regular or singular) the expectation values of two q-perturbation Hamiltonians in the eigenstates of the undeformed Hamiltonian are equivalent to all orders of the perturbation expansion. As an example of singular potentials the perturbation energy spectra of the q-deformed Coulomb potential are studied.
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    The European physical journal 28 (2003), S. 341-351 
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    Notes: Abstract. We analyze the effects of CP violating phases in a fully left-right extension of the minimal supersymmetric model. These phases appear from both the heavy and light neutrino sectors: two CKM-type phases, and four Majorana phases. We study observable effects of these phases in lepton flavor violating decays, such as the T-odd asymmetry in $\mu^+ \rightarrow e^+e^+e^-$ , as well as in the leptonic electric dipole moments. We impose the experimental constraints from the mixing of light neutrinos and analyze cases in which the heavy and light neutrinos are either degenerate, or hierarchical, and highlight the dominant variables in each case. CP violating phases in both the heavy and light neutrino sectors of the left-right supersymmetric model have unique features which, if tested in the charged lepton sector, may distinguish the model from other supersymmetric scenarios.
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    The European physical journal 28 (2003), S. 405-414 
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    Notes: Abstract. We consider quantum electrodynamics with additional coupling of spinor fields to the space-time independent axial vector violating both Lorentz and CPT-symmetries. The Fock-Schwinger proper-time method is used to calculate the one-loop effective action up to the second order in the axial vector and to all orders in the space-time independent electromagnetic field strength. We find that the Chern-Simons term is not radiatively induced and that the effective action is CPT-invariant in the given approximation.
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    The European physical journal 28 (2003), S. 321-328 
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    Notes: Abstract. We perform a detailed study of the consistency between different sets of polarized deep inelastic scattering data and theory, from the standpoint of a next to leading order QCD global analysis, and following the criteria proposed by Collins and Pumplin. In face of recent suggestions that challenge the usual assumption about parent parton spin independence of unpolarized fragmentation functions, we specially focus on polarized semi-inclusive data.
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    The European physical journal 28 (2003), S. 415-424 
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    Notes: Abstract. First, we present a simple confining abelian pure gauge theory. Classically, its kinetic term is not positive definite, and it contains a simple UV regularized F4 interaction. This provokes the formation of a condensate $\phi \sim F^2$ such that, at the saddle point $\widehat{\phi}$ of the effective potential, the wave function normalization constant of the abelian gauge fields $Z_{eff}(\widehat{\phi})$ vanishes exactly. Then we study SU(2) pure Yang-Mills theory in an abelian gauge and introduce an auxiliary field $\rho$ for a BRST invariant condensate of dimension 2, which renders the charged sector massive. Under simple assumptions its effective low energy theory reduces to the confining abelian model discussed before, and the VEV of $\rho$ is seen to scale correctly with the renormalization point. Under these assumptions, the confinement condition Z eff = 0 also holds for the massive charged sector, which suppresses the couplings of the charged fields to the abelian gauge bosons in the infrared regime.
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    The European physical journal 28 (2003), S. 395-403 
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    Notes: Abstract. Explicit path integration is carried out for the Green's functions of special relativistic harmonic oscillators in (1+1)- and (3+1)-dimensional Minkowski space-time modeled by a Klein-Gordon particle in the universal covering space-time of the anti-de Sitter static space-time. The energy spectrum together with the normalized wave functions are obtained. In the non-relativistic limit, the bound states of the one- and three-dimensional ordinary oscillators are regained.
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    The European physical journal 28 (2003), S. 313-319 
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    Notes: Abstract. We discuss the predictions of perturbative QCD for angular flows of final state particles in two and three jet events including their cms energy and jet resolution (ycut) dependence. The simple analytical formulae for gluon bremsstrahlung from primary partons, modified for gluon cascading, reproduce the main features of the experimental data well. For ycut-selected events, the particle flow is derived from a superposition of colour dipoles in much the same way that photon radiation is derived from electric dipoles.
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    The European physical journal 28 (2003), S. 297-304 
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    Notes: Abstract. The energy spectrum and the cross section of photonuclear interactions of 180 GeV muons in iron were measured at the CERN SPS using prototype modules of the ATLAS hadron calorimeter. The differential cross section $(N_{A}/A)v{d}\sigma/{d}v$ for a muon fractional energy loss $v = \Delta E_{\mu} / E_{\mu}$ was measured in the range 0.1〈v〈1. The integrated cross section $(N_{A}/A) \int_{0.1}^{1} v{d}\s igma/{d}v$ is $(0.26 \pm 0.03_{stat} \pm 0.03_{syst})\cdot 10^{-6}$ cm2g-1 in agreement with the theoretical prediction of $0.267 \cdot 10^{-6}$ cm2g-1. The best adjustment of the data to the theory is achieved for the value of $\sigma_{\gamma N} = (115 \pm 18_stat \pm 15_{syst})\mu {b}$ of the photon-nucleon cross section for photons with energies in the range from 18 to 180 GeV.
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    The European physical journal 28 (2003), S. 425-430 
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    Notes: Abstract. We calculate the effective potential for the WLPNGB in a world with a circular latticized extra dimension. The mass of the Wilson line pseudo-Nambu-Goldstone boson (WLPNGB) is calculated from the one-loop quantum effect of scalar fields at zero and finite temperature. We show that a series expansion by the modified Bessel functions is useful to calculate the one-loop effective potentials.
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  • 77
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    Notes: Abstract. In a class of SUSY SO(10) with $SU(2)_L\times SU(2)_R\times U(1)_{B-L}\times SU(3)_C (g_{2L}\neq g_{2R})$ intermediate gauge symmetry, we observe that the prediction on the unification mass (M U ) is unaffected by Planck-scale-induced gravitational and intermediate-scale threshold effects, although the intermediate scale (M I ) itself is subject to such corrections. In particular, without invoking the presence of additional lighter scalar degrees of freedom but including plausible and reasonable threshold effects, we find that interesting solutions for neutrino physics corresponding to $M_{I}\simeq 10^{10}$ -1013 GeV and $M_{U}\simeq(5$ - $6)\times10^{17}$ GeV are permitted in the minimal models. The possibilities of low-mass right-handed gauge bosons corresponding to $M_{I}\simeq 1$ -10 TeV consistent with the CERN-LEP data are pointed out in a number of models in which threshold effects are included using effective mass parameters.
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    The European physical journal 28 (2003), S. 381-388 
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    Notes: Abstract. We study scalar leptoquark production at TESLA and CLIC based $e\gamma$ colliders. Both direct and resolved contributions to the cross section are examined. We find that the masses of scalar leptoquarks can be probed up to about 0.9 TeV at TESLA and 2.6 TeV at CLIC.
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    The European physical journal 28 (2003), S. 365-374 
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    Notes: Abstract. We discuss the perspectives of testing the right-handed Majorana mass scale MR of the SUSY see-saw model in the mSUGRA framework. Lepton-flavor violating low energy processes are analyzed in recently proposed post-LEP benchmark scenarios, taking into account present uncertainties and future developments in the neutrino sector. Non-observation of $\mu \rightarrow e \gamma$ in the next-generation PSI experiment will provide upper bounds on MR of the order of $10^{12\div 14}$ GeV, while on the other hand, a positive signal for $\tau \rightarrow \mu \gamma$ at SUPERKEKB or the LHC may determine MR for a given mSUGRA scenario with an accuracy of a factor of 2.
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    The European physical journal 28 (2003), S. 431-435 
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    Notes: Abstract. We consider a relativistic superalgebra in the picture in which the time and spatial derivative cannot be presented in the operators of the particle. The supersymmetry generators as well as the Hamilton operators for the massive relativistic particles with spin 0 and spin 1/2 are expressed in terms of the principal series of the unitary representations of the Lorentz group. We also consider the massless case. New Hamilton operators are constructed for the massless particles with spin 0 and spin 1/2.
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    The European physical journal 28 (2003), S. 329-333 
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    Notes: Abstract. We use the transverse-momentum dependence of the cross section for the diffractive dissociation of high energy pions to two jets to study some non-perturbative light-cone wave functions of the pion. We compare the predictions for this distribution by Gaussian and Coulomb wave functions as well as the wave function derived from a solution of the light-cone Hamiltonian in the singlet model. We conclude that this experimentally measured information provides a powerful tool for these studies.
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    The European physical journal 28 (2003), S. 335-340 
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    Notes: Abstract. The quarkonia-glueball structure of $\eta$ , $\eta^{'}$ and $\eta(1440)$ is phenomenologically deduced from the updated world average data including two-photon decays of pseudoscalar mesons, radiative decays between pseudoscalar and vector mesons, decays of $J/\psi$ into a vector and a pseudoscalar meson, and radiative decays of $J/\psi$ . Corrections due to SU(3) flavor symmetry breaking, non-ideal $\omega$ - $\phi$ mixing, double OZI and electromagnetic amplitudes of $J/\psi$ decays into a vector and a pseudoscalar meson, and three-gluon-annihilation amplitudes of radiative decays of $J/\psi$ are included in our analysis. Some predictions on the decays involving $\eta(1410)$ are presented, which can be tested at Beijing Electron Positron Collider/Beijing Spectrometer (BEPC/BES) with 50 million $J/\psi$ events.
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    The European physical journal 28 (2003), S. 375-380 
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    Notes: Abstract. The cross section for the reaction $e^-e^-\;\to\; \ell^-\ell^-$ ( $\ell = \mu,\tau$ ) is calculated in models with heavy Majorana neutrinos mediating lepton number violating amplitudes at the loop level. The contributing four-point functions are evaluated exactly (numerically) taking into account the full propagator dependence on external momenta, thereby extending to the energy range of interest for the next linear colliders an earlier approximate low energy calculation. The amplitude shows a non-decoupling behavior relative to the heavy Majorana neutrino masses, but due to the stringent bounds on heavy-light mixing the signal cross section attains observable values only for the less constrained $\tau$ signal. The cross section induced by lepton number violation in the SU(2) L doublet sneutrino sector of supersymmetric extensions of the standard model is constrained by the upper limits on neutrino masses and probably too tiny to be observable.
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    The European physical journal 28 (2003), S. 561-571 
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    Notes: Abstract. We introduce a class of self-interacting scalar theories in which the various coupling constants obey a recursive relation. These imply a particularly simple form for the generating function of the Feynman amplitudes with vanishing external momenta, as well as for the effective potential. In addition we discuss an interesting duality inherent in these models. Specializing to the case of zero spacetime dimensions we find intriguing nullification properties for the amplitudes.
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    The European physical journal 28 (2003), S. 535-543 
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    Notes: Abstract. The fuzzy bag is a hadronic model which has features both of the bag model (energy-momentum conservation, QCD vacuum energy) and of relativistic potential models (confinement achieved through a potential). It is also a chiral model, with the unique property that the pion field is suppressed in the interior of the bag by means of a scalar potential, and yet chiral symmetry is preserved. This scalar potential allows one to control how far the pion field can penetrate in the interior of the bag. We calculate the masses of the fundamental baryon octet taking into account the center of mass, one-gluon exchange and one-pion exchange corrections. We also calculate the nucleon axial charge, charge radii and magnetic moments including center of mass and recoil corrections. The agreement with experiment is excellent, and the results indicate that the pion field is suppressed only very close to the center of the bag.
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    The European physical journal 28 (2003), S. 475-481 
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    Notes: Abstract. Theoretical predictions show that at low values of the Bjorken parameter x the spin structure function, g1, is influenced by large logarithmic corrections, $\ln^2(1/x)$ , which may be predominant in this region. These corrections are also partially contained in the NLO part of the standard DGLAP evolution. Here we calculate the nucleon structure function, g1, and the gluon distribution, $\Delta g$ , using the unified evolution equations written for the singlet and the non-singlet parton distributions. These equations include (i) the terms which describe the NLO DGLAP evolution and (ii) the ladder and non-ladder terms which contribute to the resummation of $\ln^2(1/x)$ . Subtractions of singularities from the evolution kernels are performed so as to avoid double counting the double logarithmic contributions coming from the NLO DGLAP and the ladder and non-ladder terms. The sensitivity of the results to the factorization scheme applied is tested by introducing the DGLAP terms into the evolution equations at two different factorization schemes.
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    The European physical journal 28 (2003), S. 483-493 
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    Notes: Abstract. Two photon collisions at high energy have an important theoretical advantage: the simplicity of the initial state, which gives us a unique opportunity to calculate these processes for large virtualities of both photons in the perturbative QCD approach. In this paper we study QCD saturation in two photon collisions in the framework of the Glauber-Mueller approach. The Glauber-Mueller formula is derived emphasising the impact parameter dependence (bt) of the dipole-dipole amplitude. It is shown that non-perturbative QCD contributions are needed to describe the large b t behaviour, and the way how to deal with them is suggested. Our approach can be viewed as the model for the saturation in which the entire impact parameter dependence is determined by the initial conditions. The unitarity bound for the total cross section, its energy dependence as well as predictions for future experiments are discussed. It is argued that the total cross section increases faster than any power of $ \ln(1/x)$ in a wide range of energy or x, namely $\sigma(\gamma^*$ - $\gamma^*) \propto (1/Q^2) \exp(a \sqrt{\ln(1/x)}) \leq 1/m^2_{\pi}$ , where $\exp(a \sqrt{\ln(1/x)})$ reflects the x dependence of the gluon density $xG \propto \exp(2 a \sqrt{\ln(1/x)})$ and $m_{\pi}$ is the pion mass.
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    The European physical journal 28 (2003), S. 495-513 
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    Notes: Abstract. We have calculated the next-to-leading order cross section for the inclusive production of charm quarks as a function of the transverse momentum pT and the rapidity in two approaches using massive or massless charm quarks. For the single-resolved cross section we have derived the massless limit from the massive theory. We find that this limit differs from the genuine massless version with $\overline{{MS}}$ factorization by finite corrections. By adjusting subtraction terms we establish a massive theory with $\overline{{MS}}$ subtraction which approaches the massless theory very fast with increasing transverse momentum. With these results and including the equivalent results for the direct cross section obtained previously as well as double-resolved contributions, we calculate the inclusive $D^{*\pm}$ cross section in $\gamma \gamma$ collisions using realistic evolved non-perturbative fragmentation functions and compare with recent data from the LEP collaborations ALEPH, L3 and OPAL. We find good agreement.
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    The European physical journal 28 (2003), S. 557-560 
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    Notes: Abstract. Quantum field theories based on non-commutative space-time (NCQFT) have been extensively studied recently. However no NCQFT model which can uniquely describe the strong and electroweak interactions has been constructed. This prevents one to make a consistent and systematic study of non-commutative space-time. In this work we construct a NCQFT model based on the trinification gauge group $SU(3)_C\times SU(3)_{{L}}\times SU(3)_{R}$ . A unique feature of this model, that all matter fields (fermions and Higgs bosons) are assigned to (anti-) fundamental representations of the factor SU(3) groups, allows us to construct a NCQFT model for strong and electroweak interactions and their unification without ambiguities. This model provides an example which allows one to make a consistent and systematic study of non-commutative space-time phenomenology. We also comment on some related issues regarding extensions to E6 and $U(3)_C\times U(3)_{L}\times U(3)_{R}$ models.
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    The European physical journal 28 (2003), S. 525-533 
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    Notes: Abstract. An analysis of the Coulombic amplitude and its interference with the nuclear amplitude which is driven by the three-component pomeron is presented. It is shown that different approaches towards the evaluation of the Coulomb phase give approximately uniform results at all energies and the differences are negligible at RHIC and LHC energies. We show that the use of the amplitude which was fitted to accommodate the nucleon data only (in the region $0.01 \le \vert t\vert \le 14.5$ (GeV2)), combined with the Coulomb amplitude, reproduces the existing data in the Coulomb interference domain quite accurately without any adjustment of the parameters. As a consequence, we predict the differential cross section in the region of the Coulomb nucleon interference for both RHIC and LHC energies.
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    The European physical journal 28 (2003), S. 455-473 
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    Notes: Abstract. We determine the uncertainties on observables arising from the errors on the experimental data that are fitted in the global MRST2001 parton analysis. By diagonalizing the error matrix we produce sets of partons suitable for use within the framework of linear propagation of errors, which is the most convenient method for calculating the uncertainties. Despite the potential limitations of this approach we find that it can be made to work well in practice. This is confirmed by our alternative approach of using the more rigorous Lagrange multiplier method to determine the errors on physical quantities directly. As particular examples we determine the uncertainties on the predictions of the charged-current deep-inelastic structure functions, on the cross-sections for W production and for Higgs boson production via gluon-gluon fusion at the Tevatron and the LHC, on the ratio of W- to W+ production at the LHC and on the moments of the non-singlet quark distributions. We discuss the corresponding uncertainties on the parton distributions in the relevant x,Q2 domains. Finally, we briefly look at uncertainties related to the fit procedure, stressing their importance and using $\sigma_W$ , $\sigma_H$ and extractions of $\alpha_S(M_Z^2)$ as examples. As a by-product of this last point we present a slightly updated set of parton distributions, MRST2002.
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    The European physical journal 28 (2003), S. 515-523 
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    Notes: Abstract. We calculate the $B\to P$ , $B\to V$ (P is the light pseudoscalar meson, V the light vector meson) form factors in the large-recoil limit in the perturbative QCD approach, including both the vector (axial vector) and tensor operators. In general there are two leading components $\phi_B$ and $\bar{\phi}_B$ for the B meson wave functions. We consider both contributions of them. Sudakov effects ( $k_{\perp}$ and threshold resummation) are included to regulate the soft end-point singularity. By choosing the hard scale as the maximum virtualities of the internal particles in the hard b quark decay amplitudes, Sudakov factors can effectively suppress the long-distance soft contribution. The hard contribution can be dominant in these approaches.
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    The European physical journal 28 (2003), S. 437-449 
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    Notes: Abstract. The inclusive production of D $^{*\pm}$ mesons in two-photon collisions is measured with the ALEPH detector at e+e- centre-of-mass energies from 183 GeV to 209 GeV. A total of $360 \pm 27$ D $^{*\pm}$ meson events are observed from an integrated luminosity of 699pb-1. Contributions from direct and single-resolved processes are separated using the ratio of the transverse momentum $p_{t}^{D^{*\pm}}$ of the D $^{*\pm}$ to the visible invariant mass Wvis of the event. Differential cross sections of D $^{*\pm}$ production as functions of $p_{t}^{D^{*\pm}}$ and the pseudorapidity $\vert\eta^{D^{*\pm}}\vert $ are measured in the range 2 GeV $/c 〈 p_{t}^{D^{*\pm}} 〈 12$ GeV/c and $ \vert\eta^{D^{*\pm}}\vert 〈 1.5 $ . They are compared to next-to-leading order (NLO) perturbative QCD calculations. The extrapolation of the integrated visible D $^{*\pm}$ cross section to the total charm cross section, based on the Pythia Monte Carlo program, yields $ \sigma (e^+e^- \rightarrow e^+e^- c\bar{c})_{\left〈\sqrt{s}\right〉 = 197 GeV} = 731 \pm 74_{stat} \pm 47_{syst} \pm 157_{extr}$ pb .
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    The European physical journal 28 (2003), S. 451-454 
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    Notes: Abstract. We discuss a two scalar doublets model which induces the Higgs mechanism by means of a seesaw mechanism. This model naturally predicts a light Higgs scalar whose mass is suppressed by the grand unification scale. The model requires an intermediate scale between the electroweak symmetry breaking scale and the grand unification scale at 109 GeV. Below this intermediate energy scale the usual standard model appears as an effective theory. An implementation of this mechanism in models where the Planck scale is in the TeV region is discussed.
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    The European physical journal 28 (2003), S. 545-555 
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    Notes: Abstract. We deconstruct the non-supersymmetric SU(5) breaking by discrete symmetry on the space-time $M^4\times S^1$ and $M^4\times S^1/(Z_2\times Z_2')$ in the Higgs mechanism deconstruction scenario. Also we explain the subtle point of how to exactly match the continuum results with the latticized results on the quotient space S 1 /Z 2 and $S^1/(Z_2\times Z_2')$ . We also propose an effective deconstruction scenario and discuss the gauge symmetry breaking by the discrete symmetry on the theory space in this approach. As an application, we suggest the GN unification where GN is broken down to $SU(3)\times SU(2)\times U(1)^{n-3}$ by the bifundamental link fields and the doublet-triplet splitting can be achieved.
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    The European physical journal 31 (2003), S. 563-569 
    ISSN: 1434-6036
    Keywords: PACS. 68.35.Ct Interface structure and roughness – 05.40.-a Fluctuation phenomena, random processes, noise, and Brownian motion – 02.50.-r Probability theory, stochastic processes, and statistics – 81.15.Aa Theory and models of film growth
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    Notes: Abstract: The relationship between a microscopic parameter p, that is related to the probability of choosing a mechanism of deposition, and the stochastic equation for the interface's evolution is studied for two different models. It is found that in one model, that is similar to ballistic deposition, the corresponding stochastic equation can be represented by a Kardar-Parisi-Zhang (KPZ) equation where both λ and ν depend on p in the following way: ν(p) = νp and λ(p) = λp 3/2. Furthermore, in the other studied model, which is similar to random deposition with relaxation, the stochastic equation can be represented by an Edwards-Wilkinson (EW) equation where ν depends on p according to ν(p) = νp 2. It is expected that these results will help to find a framework for the development of stochastic equations starting from microscopic details of growth models.
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    The European physical journal 35 (2003), S. 233-238 
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    Notes: Abstract. We show that the infrared reflectance of the quasi-one dimensional charge-density-wave (CDW) conductor K0.3MoO3 (blue bronze) varies with position when a voltage greater than the CDW depinning threshold is applied. The spatial dependence and spectra associated with these changes are generally as expected from the electro-transmission [B.M. Emerling, et al., Eur. Phys. J. B 16, 295 (2000)], but there are differences which might be associated with changes in the CDW properties on the surface. We have examined the electro-reflectance spectrum associated with CDW current investigation for light polarized parallel to the conducting chains for signs of expected current-induced intragap states, and conclude that the density of any such states is at least an order of magnitude less than expected.
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    The European physical journal 34 (2003), S. 115-118 
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    Notes: Abstract. We have examined the mean first passage time ( $\langle T\rangle$ ) for a particle driven by colored non-Gaussian noise. As we depart from the Gaussian behavior, the $\langle T\rangle$ decreases regularly to a limiting value, i.e., the barrier crossing rate can be accelerated to a limiting value by increasing the non-Gaussianity of the noise. For the non-Gaussian noise driven process $\langle T\rangle$ increases linearly with increasing damping constant or noise correlation time. But this increasing behavior is almost exponential in nature for the Gaussian noise driven process.
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    The European physical journal 34 (2003), S. 119-129 
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    Notes: Abstract. Recently we have used a cellular automata model which describes the dynamics of a multi-connected network to reproduce the refractory behavior and aging effects obtained in immunization experiments performed with mice when subjected to multiple perturbations. In this paper we investigate the similarities between the aging dynamics observed in this multi-connected network and the one observed in glassy systems, by using the usual tools applied to analyze the latter. An interesting feature we show here, is that the model reproduces the biological aspects observed in the experiments during the long transient time it takes to reach the stationary state. Depending on the initial conditions, and without any perturbation, the system may reach one of a family of long-period attractors. The perturbations may drive the system from its natural attractor to other attractors of the same family. We discuss the different roles played by the small random perturbations ("noise") and by the large periodic perturbations ("immunizations").
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    Notes: Abstract. Mössbauer spectrometry and magnetic measurements are employed to experimentally investigate the magnetic behavior of nanocrystalline Fe73.5Cu1Nb3Si13.5B9 ribbons obtained by appropriate annealing of the amorphous precursor. A detailed analysis of the correlation between the microstructure of annealed samples and their magnetic properties is provided. Thermomagnetic data allow the Curie temperatures of both amorphous residual matrix and nanocrystalline phase to be estimated. The differences between Curie temperatures of amorphous residual matrix and amorphous precursor are investigated and explained in terms of magnetic polarization of the matrix by exchange fields arising from the nanocrystalline grains. Theoretical systems of spins consisting of a single ferromagnetic nanocrystalline grain immersed in weakly ferromagnetic environment, quite similar to our real samples, are considered and their magnetic behavior is investigated by Monte Carlo simulation of low temperature spin ordering, with emphasize on the matrix-nanocrystalline grain interface which is shown to exhibit peculiar magnetic behavior. The magnetic features of the matrix-nanocrystalline grain interface are studied, as depending on matrix-nanocrystalline grain exchange coupling as well as crystalline fraction of the nanocrystalline systems.
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