784 research outputs found
Stability Analysis of Converter Control Modes in Low-Inertia Power Systems
This paper deals with the small-signal stability analysis of converter control modes in low-inertia power systems. For this purpose, a detailed differential-algebraic equation model of the voltage source converter and its control scheme is developed. Both grid-forming and grid-feeding concepts have been considered, as well as different active power controllers based on traditional droop and virtual inertia emulation. An eigenvalue analysis of the linearized state-space system is conducted and the performance of different control configurations is compared. Furthermore, various bifurcation studies have been completed and conclusions on stability margins have been drawn with respect to control sensitivity and robustness
Discovering SUSY in the first LHC run
4 pĂĄginas, 1 figura.-- Trabajo presentado a la Fifth Conference on Physics at LHC celebrada en Hamburgo (Alemania) del 7 al 12 de junio de 2010.We analyze the potential of the first LHC physics run, assuming 1 fbâ1 at ps = 7 TeV, to
discover Supersymmetry (SUSY). The results are based on SUSY parameter fits following a
frequentist approach. They include the experimental constraints from electroweak precision
data, (g â 2)Îź, B physics and cosmological data. The two SUSY models under consideration
are the constrained MSSM (CMSSM) with universal soft supersymmetry-breaking
mass parameters, and a model with common non-universal Higgs mass parameters in the
superpotential (NUHM1). We find that large parts of the regions preferred at the 68%
C.L. are accessible to early LHC running.Work
supported in part by the European Communityâs Marie-Curie Research Training Network under
contract MRTN-CT-2006-035505 âTools and Precision Calculations for Physics Discoveries at
Collidersâ (HEPTOOLS).Peer reviewe
A case of trisomy 8 and loss of the Y-chromosome as secondary aberrations in a ten year old boy with de novo AML FAB M2 and t(16;21)(q24;q22)
Case report of a translocation : A case of trisomy 8 and loss of the Y-chromosome as secondary aberrations in a ten year old boy with de novo AML FAB M2 and t(16;21)(q24;q22)
Biological responses to a resumption in river flow in a freshwaterdeprived, permanently open Southern African estuary
The Kariega Estuary is a freshwater-deprived system due to numerous impoundments in the catchment. This system has had little or no horizontal salinity gradient over the last 15 years, with hypersaline conditions sometimes predominating in the upper reaches. Following high rainfall events in the catchment during the spring of 2006, including a flood event (approximate 1:10 year) in August 2006, a series of riverine pulses entered the estuary and a horizontal salinity gradient was established. This study examined the influence of this freshwater pulse on four components of the biota within the estuary, namely the zooplankton, and larval, littoral and demersal fishes. The study demonstrated that in three of these components elevated densities were recorded following the riverine input, with only the littoral fishes retaining an almost constant density. In addition, changes in the relative contributions of the estuarine utilisation classes for all three fish groups examined indicated that freshwater input into these systems positively influences the abundances. This has significant implications for water managers as it demonstrates the importance of an Ecological Reserve (defined as âthe water required to protect the aquatic ecosystems of the water resourceâ) for this system.Keywords: biotic response, freshwater pulse, river inflow, Kariega Estuar
CTGF (IGFBP-rP2) is specifically expressed in malignant lymphoblasts of patients with acute lymphoblastic leukaemia (ALL)
Connective tissue growth factor (CTGF) is a major chemotactic and mitogenic factor for connective tissue cells. The amino acid sequence shares an overall 28â38% identity to IGFBPs and contains critical conserved sequences in the amino terminus. It has been demonstrated that human CTGF specifically binds IGFs with low affinity and is considered to be a member of the IGFBP superfamily (IGFBP-rP2). In the present study, the expression of CTGF (IGFBP-rP2) in human leukaemic lymphoblasts from children with acute lymphoblastic leukaemia (ALL) was investigated. RNA samples from tumour clones enriched by ficoll separation of bone marrow or peripheral blood mononuclear cells (MNC) from 107 patients with childhood ALL at diagnosis and 57 adult patients with chronic myeloid leukaemia (CML) were studied by RT-PCR. In addition MNC samples from children with IDDM and cord blood samples from healthy newborns were investigated as control groups. Sixty-one percent of the patients with ALL (65 of 107) were positive for CTGF (IGFBP-rP2) expression. In the control groups, no expression of CTGF (IGFBP-rP2) in peripheral MNC was detected, and in the group of adult CML patients only 3.5% (2 of 57) were positive for this gene. The role of CTGF (IGFBP-rP2) in lymphoblastic leukaemogenesis requires further evaluation, as does its potential utility as a tumour marker. Š 2000 Cancer Research Campaig
Migration of superior vena cava stent
There has been a recent increase in the use of endovascular prostheses resulting in complex surgical and interventional complications not previously recognised. We report a case of Superior vena cava stenosis treated with a wallstent which migrated to the right atrium, necessitating a combined radiological and surgical approach to retrieve it
A multidisciplinary study of a small, temporarily open/closed South African estuary, with particular emphasis on the influence of mouth state on the ecology of the system
In 2005/2006 a multidisciplinary research programme that included studies on the hydrodynamics, sediment dynamics, macronutrients, microalgae, macrophytes, zoobenthos, hyperbenthos, zooplankton, ichthyoplankton, fish and birds of the temporarily open/closed East Kleinemonde Estuary was conducted. Particular attention was given to the responses of the different ecosystem components to the opening and closing of the estuary mouth and how this is driven by both riverine and marine events. Using a complementary dataset of daily estuary mouth conditions spanning a 14-year period, five distinct phases of the estuary were identified, including closed (average = 90% of the days), outflow (<1%), tidal (9%) and semi-closed (<1%). The open-mouth phase is critical for the movements of a number of estuary-associated fish (e.g. Rhabdosargus holubi) and invertebrates (e.g. Scylla serrata) between the estuary and sea. The timing of this open phase has a direct influence on the ability of certain estuaryassociated fish (e.g. Lithognathus lithognathus) and invertebrates (e.g. Palaemon peringueyi) to successfully recruit into the system, with a spring opening (October/November) being regarded as optimal for most species. The type of mouth-breaching event and outflow phase is also important in terms of the subsequent salinity regime once the berm barrier forms. A deep mouth breaching following a large river flood tends to result in major tidal inputs of marine water prior to mouth closure and therefore higher salinities (15â25). Conversely, a shallow mouth breaching with reduced tidal exchange during the open phase often leads to a much lower salinity regime at the time of mouth closure (5â15). The biota, especially the submerged macrophytes, respond very differently to the above two scenarios, with Ruppia cirrhosa benefiting from the former and Potamogeton pectinatus from the latter. River flooding and the associated outflow of large volumes of water through the estuary can result in major declines in zooplankton, zoobenthos, hyperbenthos and fish populations during this phase. However, this resetting of the estuary is necessary because certain marine invertebrate and fish species are dependent on the opening of the estuary mouth in order to facilitate recruitment of larvae and post-larvae into the system from the sea. Slight increases in the numbers of certain piscivorous and resident wading bird species were recorded when the estuary mouth opened, possibly linked to increased feeding opportunities during that phase
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ĐŃĐżŃŃĐşĐ˝Đ°Ń ĐşĐ˛Đ°ĐťĐ¸ŃикаŃĐ¸ĐžĐ˝Đ˝Đ°Ń ŃайОŃĐ° ŃОдоŃĐśĐ¸Ń 160 ŃŃŃаниŃŃ ĐźĐ°ŃинОпиŃнОгО ŃокŃŃĐ°, 29 ŃайНиŃ, 27 ŃиŃŃнкОв, 1 ŃпиŃОк иŃпОНŃСОваннŃŃ
иŃŃĐžŃникОв иС 18 наиПонОваниК, 9 ĐżŃиНОМониК.
ĐĐąŃокŃОП иŃŃĐťĐľĐ´ĐžĐ˛Đ°Đ˝Đ¸Ń ŃвНŃĐľŃŃŃ ĐłĐ°ĐˇĐžŃĐ°ŃĐżŃодоНиŃоНŃĐ˝Đ°Ń ŃŃĐ°Đ˝ŃиŃ.
ĐŚĐľĐťŃ ŃайОŃŃ â ŃаСŃайОŃка авŃОПаŃиСиŃОваннОК ŃиŃŃĐľĐźŃ ŃĐżŃĐ°Đ˛ĐťĐľĐ˝Đ¸Ń ĐĐ ĐĄ Ń Đ¸ŃпОНŃСОваниоП ĐĐĐ, на ĐžŃнОво вŃĐąŃаннОК SCADA-ŃиŃŃоПŃ.
РданнОП ĐžŃŃĐľŃĐľ ОпиŃĐ°Đ˝ ĐżŃОиСвОдŃŃвоннŃĐš ĐżŃĐžŃĐľŃŃ Đ˝Đ° гаСОŃĐ°ŃĐżŃодоНиŃоНŃнОК ŃŃĐ°Đ˝Ńии ĐĐ°ŃайинŃкОгО ĐĐĐŁĐĐ, Đ° ŃакМо вŃŃĐ˛ĐťĐľĐ˝Ń ĐżŃОиСвОдŃŃвоннŃĐľ ĐżŃĐžĐąĐťĐľĐźŃ Đ¸ Đ´Đ°Đ˝Ń ŃокОПондаŃии Đ´ĐťŃ ŃОвоŃŃонŃŃĐ˛ĐžĐ˛Đ°Đ˝Đ¸Ń ŃиŃŃĐľĐźŃ ĐşĐžĐ˝ŃŃĐžĐťŃ Đ¸ ŃĐżŃĐ°Đ˛ĐťĐľĐ˝Đ¸Ń ŃŃОгО ĐżŃĐžŃĐľŃŃĐ°.Final qualifying work contains 160 pages of typewritten text, 29 tables, 27 figures, 1 list of references from 18 names, 9 applications.
The object of research is a gas distribution station.
The purpose of work - development of automated gas distribution station control system using PLC, based on the selected SCADA-system.
This report describes a manufacturing process at a gas distribution station Baraba LPUMG and identified production problems and recommendations for improving the monitoring and management of this process
Standalone vertex ďŹnding in the ATLAS muon spectrometer
A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at âs = 7 TeV collected with the ATLAS detector at the LHC during 2011
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