140 research outputs found

    The taxonomist - an endangered race : a practical proposal for its survival

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    Background: Taxonomy or biological systematics is the basic scientific discipline of biology, postulating hypotheses of identity and relationships, on which all other natural sciences dealing with organisms relies. However, the scientific contributions of taxonomists have been largely neglected when using species names in scientific publications by not citing the authority on which they are based. Discussion: Consequences of this neglect is reduced recognition of the importance of taxonomy, which in turn results in diminished funding, lower interest from journals in publishing taxonomic research, and a reduced number of young scientists entering the field. This has lead to the so-called taxonomic impediment at a time when biodiversity studies are of critical importance. Here we emphasize a practical and obvious solution to this dilemma. We propose that whenever a species name is used, the author(s) of the species hypothesis be included and the original literature source cited, including taxonomic revisions and identification literature - nothing more than what is done for every other hypothesis or assumption included in a scientific publication. In addition, we postulate that journals primarily publishing taxonomic studies should be indexed in ISISM. Summary: The proposal outlined above would make visible the true contribution of taxonomists within the scientific community, and would provide a more accurate assessment for funding agencies impact and importance of taxonomy, and help in the recruitment of young scientists into the field, thus helping to alleviate the taxonomic impediment. In addition, it would also make much of the biological literature more robust by reducing or alleviating taxonomic uncertainty. Keywords: Taxonomy crisis; taxonomic impediment; impact factor; original species description; citation index; systematic

    Unstable Hadrons in Hot Hadron Gas in Laboratory and in the Early Universe

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    We study kinetic master equations for chemical reactions involving the formation and the natural decay of unstable particles in a thermal bath. We consider the decay channel of one into two particles, and the inverse process, fusion of two thermal particles into one. We present the master equations the evolution of the density of the unstable particles in the early Universe. We obtain the thermal invariant reaction rate using as an input the free space (vacuum) decay time and show the medium quantum effects on π+πρ\pi+\pi \leftrightarrow \rho reaction relaxation time. As another laboratory example we describe the K+KϕK+K \leftrightarrow \phi process in thermal hadronic gas in heavy-ion collisions. A particularly interesting application of our formalism is the π0γ+γ\pi^{0}\leftrightarrow \gamma +\gamma process in the early Universe. We also explore the physics of π±\pi^{\pm} and μ±\mu^{\pm} freeze-out in the Universe.Comment: 13 pages, 9 figures, published in Physical Review

    Image quality and high contrast improvements on VLT/NACO

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    NACO is the famous and versatile diffraction limited NIR imager and spectrograph with which ESO celebrated 10 years of Adaptive Optics at the VLT. Since two years a substantial effort has been put in to understanding and fixing issues that directly affect the image quality and the high contrast performances of the instrument. Experiments to compensate the non-common-path aberrations and recover the highest possible Strehl ratios have been carried out successfully and a plan is hereafter described to perform such measurements regularly. The drift associated to pupil tracking since 2007 was fixed in October 2011. NACO is therefore even better suited for high contrast imaging and can be used with coronagraphic masks in the image plane. Some contrast measurements are shown and discussed. The work accomplished on NACO will serve as reference for the next generation instruments on the VLT, especially those working at the diffraction limit and making use of angular differential imaging (i.e. SPHERE, VISIR, possibly ERIS).Comment: 14 pages, 5 figures, SPIE 2012 Astronomical Instrumentation Proceedin

    Assessment of environmental and economic efficiency of iron ore breaking technology using emulsion explosives

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    Methodology for calculating parameters of drilling and blasting operations for stoping works in mines of Kryvorozhskiy basin and PJSC «Zaporizhskiy iron-ore plant» has been improved with the help of established coefficient of relative capacity for the Ukrainit-PM-2B explosive. A new technology of stoping operations for ore breaking by square-chamber methods at deposit thickness more than 5 m is proposed which assumes usage of emulsion explosives and downward drilling of production hole rings in the direction of underlying drilling horizons. Ecological and economical effectiveness of the proposed ore breaking technology implemented in the extraction chambers was estimated. Regularities of harmful substances hazard index changing were established depending on distance to the emission point when trotyl-contained and emulsion explosives are used. Implementation of the proposed technology allows decreasing prime-cost of 1 ton of ore by 15 % per one extraction unit

    High temperature indentation creep and nanoindentation testing of superalloys and TiAl alloys

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    Measuring of the high temperature mechanical behaviour of materials by local testing has become a key task in the field of nanomechanics. However, gaining access to the application temperature of many metallic high temperature materials, which is in the range of 600°C - 1100°C, is quite difficult. In addition, creep parameters can only be determined by long time measurements, where drift influences become a severe challenge. Here we present a new approach of indentation creep testing with a flat punch indenter. For this, a thermo mechanical analyzer with very precise temperature control is used, which allows testing at temperatures up to 1200°C. A flat punch indenter with a diameter of around 10 µm allows for example local investigations of the creep properties on the dendritic scale of superalloys. This approach is also interesting to study the creep properties along the gradient of diffusion couples. Here, first test measurements on superalloys and other materials are presented and discussed. For comparison also high temperature nanoindentation measurements will be shown. Such measurements have been conducted on a multiphase titanium aluminide alloy from room temperature up to 600°C. The results show, that the hardness of the (β0+ω0)-composite phase is the highest among all phases and remains constant up to the service temperature. Both approaches of high temperature testing are compared and the prospect of these methods will be discussed

    ВыБОР МЕСТ УСТАНОВКИ БАТАРЕЙ КОНДЕНСАТОРОВ ЗАДАННОЙ МОЩНОСТИ И РЕКОНФИГУРАЦИЯ В РАСПРЕДЕЛИТЕЛЬНыХ СЕТЯХ С ПОМОЩЬЮ СЕЛЕКТИВНОГО МЕТОДА РОЯ ЧАСТИЦ

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    Запропоновано селективний метод рою частинок для вирішення проблем оптимізації структури і ре- жимів розподільних мереж. Метод був використаний для зниження втрат електроенергії і поліпшення якості напруги шляхом сумісної оптимізації конфігурації розподільної мережі та місць встановлення і потужності батарей конденсаторів. На прикладі двох тестових схем показана ефективність запропо- нованого методу.Предложен селективный метод роя частиц для решения проблем оптимизации структуры и режимов распределительных сетей. Метод был использован для снижения потерь электроэнергии и улучшения качества напряжения путем совместной оптимизации конфигурации распределительной сети и мест установки и мощности батарей конденсаторов. На примере двух тестовых схем показана эффектив- ность предлагаемого метода

    Clonal karyotype evolution involving ring chromosome 1 with myelodysplastic syndrome subtype RAEB-t progressing into acute leukemia

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    s Karyotypic evolution is a well-known phenomenon in patients with malignant hernatological disorders during disease progression. We describe a 50-year-old male patient who had originally presented with pancytopenia in October 1992. The diagnosis of a myelodysplastic syndrome (MDS) FAB subtype RAEB-t was established in April 1993 by histological bone marrow (BM) examination, and therapy with low-dose cytosine arabinoside was initiated. In a phase of partial hernatological remission, cytogenetic assessment in August 1993 revealed a ring chromosome 1 in 13 of 21 metaphases beside BM cells with normal karyotypes {[}46,XY,r(1)(p35q31)/46,XY]. One month later, the patient progressed to an acute myeloid leukemia (AML), subtype M4 with 40% BM blasts and cytogenetic examination showed clonal evolution by the appearance of additional numerical aberrations in addition to the ring chromosome{[}46,XY,r(1),+8,-21/45,XY,r(1),+8,-21,-22/46, XY]. Intensive chemotherapy and radiotherapy was applied to induce remission in preparation for allogeneic bone marrow transplantation (BMT) from the patient's HLA-compatible son. After BMT, complete remission was clinically, hematologically and cytogenetically (normal male karyotype) confirmed. A complete hematopoietic chimerism was demonstrated. A relapse in January 1997 was successfully treated using donor lymphocyte infusion and donor peripheral blood stem cells (PB-SC) in combination with GM-CSF as immunostimulating agent in April 1997, and the patient's clinical condition remained stable as of January 2005. This is an interesting case of a patient with AML secondary to MDS. With the ring chromosome 1 we also describe a rare cytogenetic abnormality that predicted the poor prognosis of the patient, but the patient could be cured by adoptive immunotherapy and the application of donor's PB-SC. This case confirms the value of cytogenetic analysis in characterizing the malignant clone in hernatological neoplasias, the importance of controlling the quality of an induced remission and of the detection of a progress of the disease. Copyright (c) 2006 S. Karger AG, Basel

    Infrared wavefront sensing for adaptive optics assisted Galactic Center observations with the VLT interferometer and GRAVITY: operation and results

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    This article describes the operation of the near-infrared wavefront sensing based Adaptive Optics (AO) system CIAO. The Coud\'e Infrared Adaptive Optics (CIAO) system is a central auxiliary component of the Very Large Telescope (VLT) interferometer (VLTI). It enables in particular the observations of the Galactic Center (GC) using the GRAVITY instrument. GRAVITY is a highly specialized beam combiner, a device that coherently combines the light of the four 8-m telescopes and finally records interferometric measurements in the K-band on 6 baselines simultaneously. CIAO compensates for phase disturbances caused by atmospheric turbulence, which all four 8 m Unit Telescopes (UT) experience during observation. Each of the four CIAO units generates an almost diffraction-limited image quality at its UT, which ensures that maximum flux of the observed stellar object enters the fibers of the GRAVITY beam combiner. We present CIAO performance data obtained in the first 3 years of operation as a function of weather conditions. We describe how CIAO is configured and used for observations with GRAVITY. In addition, we focus on the outstanding features of the near-infrared sensitive Saphira detector, which is used for the first time on Paranal, and show how it works as a wavefront sensor detector.Comment: 12 pages, 8 figures, accepted for publication in Instruments (open access journal from mdpi

    Overview of AO calibration strategies in the ELT context

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    The scientific potential of the ELT will rely on the performance of its AO systems that will require to be perfectly calibrated before and during the operations. The actual design of the ELT will provide a constraining environment for the calibration and new strategies have to be developed to overcome these constraints. This will be particularly true concerning the Interaction Matrix of the system with no calibration source upward M4 and moving elements in the telescope. After a brief presentation of the ELT specificities for the calibration, this communication focuses on the different strategies that have already been developed to get/measure the Interaction Matrix of the system, either based on synthetic models or using on-sky measurements. First tests of these methods have been done using numerical simulations for a simple AO system and a proposition for a calibration strategy of the ELT will be presented
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