Littérature scientifique sur le sujet « Low Background systems »
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Articles de revues sur le sujet "Low Background systems"
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Miley, H. S., R. L. Brodzinski, and J. H. Reeves. "Low-background counting systems compared." Journal of Radioanalytical and Nuclear Chemistry Articles 160, no. 2 (1992): 371–85. http://dx.doi.org/10.1007/bf02037112.
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Nevinskii, I. O., and T. V. Tsvetkova. "Variations in a? background in underground low-background systems." Atomic Energy 72, no. 6 (1992): 543–45. http://dx.doi.org/10.1007/bf00760915.
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Wójcik, M., and G. Zuzel. "Low-222Rn nitrogen gas generator for ultra-low background counting systems." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 539, no. 1-2 (2005): 427–32. http://dx.doi.org/10.1016/j.nima.2004.10.023.
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Loosli, H. H., Markus Forster, and R. L. Otlet. "Background Measurements with Different Shielding and Anticoincidence Systems." Radiocarbon 28, no. 2A (1986): 615–22. http://dx.doi.org/10.1017/s0033822200007803.
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Extremely low background count rates are a necessary condition for both the measurement of 39Ar concentrations in ground and ocean water and of 14C activities in small samples using gas proportional counting techniques. A systematic comparison of the performance of three different designs of shielding systems in four different installations has been made.Background values of selected gas proportional counters were measured, compared and separated into their various components. Acceptably low backgrounds were obtained in all the systems tried. The performance of a NaI shield in a surface laboratory was found to be at least equal to the best obtained with a gas anticoincidence detector in a deep underground laboratory.
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Barton, J. C. "A comparison of sodium iodide and germanium low background counting systems." Journal of Physics G: Nuclear and Particle Physics 17, S (1991): S415—S418. http://dx.doi.org/10.1088/0954-3899/17/s/042.
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Jovančević, N., M. Krmar, D. Mrda, J. Slivka, and I. Bikit. "Neutron induced background gamma activity in low-level Ge-spectroscopy systems." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 612, no. 2 (2010): 303–8. http://dx.doi.org/10.1016/j.nima.2009.10.059.
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Theodórsson, Páll. "Quantifying Background Components of Low-Level Gas Proportional Counters." Radiocarbon 34, no. 3 (1992): 420–27. http://dx.doi.org/10.1017/s0033822200063633.
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I discuss background components of low-level gas proportional counters and show how each component can be estimated based on available data. For more reliable background analysis, further studies are suggested. Based on new information, a generation of low-level gas proportional counting systems for radiocarbon dating may emerge with lower and more predictable background.
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SAKURAI, Hirohisa. "An Application of 14C Measurement Using Low Background Liquid Scintillation Counting Systems." RADIOISOTOPES 61, no. 2 (2012): 87–93. http://dx.doi.org/10.3769/radioisotopes.61.87.
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Galatanu, N., S. Rodrigues, P. Panine, and P. Hoghoj. "More flux, less background: improvements in low power X-ray beam delivery systems." Acta Crystallographica Section A Foundations of Crystallography 67, a1 (2011): C556. http://dx.doi.org/10.1107/s0108767311085928.
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Garg, Kratika, Nirmala Ramakrishnan, Alok Prakash, and Thambipillai Srikanthan. "Rapid and Robust Background Modeling Technique for Low-Cost Road Traffic Surveillance Systems." IEEE Transactions on Intelligent Transportation Systems 21, no. 5 (2020): 2204–15. http://dx.doi.org/10.1109/tits.2019.2917560.
Texte intégralThèses sur le sujet "Low Background systems"
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SALA, ELENA. "Development of low level counting systems for high sensitivity measurements." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/52031.
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Low level counting techniques are a powerful tools in many different fields including biological and chemical tracer studies, archaeological and geological dating, investigation
of natural and induced radioactivities and the study of fundamental particles physics.
Since they play a crucial role in many applications, developments are continuously pursue to improve the extreme sensitivity typical of these techniques.
The fundamental request of low level counting techniques is the capability to detect feeble signals, characterized by low counting rates, above the background composed of spurious counts; they thus have the capability to measure very low activities of natural
and artificial radionuclides.
During my PhD work I have focused on two main applications using low level counting
systems: the search of rare physics events and the environmental monitoring.
Both the studied systems use γ spectroscopy with High Purity Germanium detectors
(HPGe).
This technique is one of the most sensitive, it exploits the excellent energy
resolution typical of such detectors and their low intrinsic background.
The first system is composed of two n-type HPGe GMX 100-95 in Low Background
configuration, they have been designed with radiopure selected materials to reach an
intrinsic background as low as possible. This work has brought to a unique configuration
associated to an electrical cooling system, different from the one that was available on
market. Since the two GMX detectors have been conceived to work in coincidence I
have optimized the measuring system studying different radionuclide decay schemes to
consider the most probable coincidences between the γ -rays emitted during the decay of
the isotope under study. A dedicated data acquisition has been developed with particular attention to the co-
incidence detection efficiency. Furthermore I have developed the analysis software to For some rare physics events experiments the only way to enhance the sensitivity is
the background reduction; for this purpose all the materials of the experimental facility
should be selected as radiopure as possible.
The development and optimization of the low background system composed of the
two GMX detectors, working in coincidence, can select suitable materials through the
measurement of very low radionuclide concentrations.
The other system I have worked on is a Broad Energy Germanium (BEGe5030) in
low background configuration. This detector can register with excellent energy resolution
and high efficiency a wide energy spectrum, from 3 keV up to 3 MeV, thanks to some of
its peculiar features. The thin dead layers surrounding the active volume and the thin
entrance window on its top are responsible for its capability to detect very low energy
radiations.
I have optimized this system using Monte Carlo simulations to detect low contamina-
tions of radionuclides in several samples.
In particular in the last century, the environmental monitoring has became an impor-
tant aspect of radio-protection; nuclear tests, nuclear accidents, wastes and fall-out in
general can release a large quantity of radionuclides. Since toxicity and radioactivity of
these contaminations are dangerous it is mandatory an environmental monitoring at the
area of interest.
Plutonium isotopes significantly contribute to the contamination due to nuclear fall-
out events in environment; since they are very toxic it is important to quickly monitor a
large number of samples in the area of interest.
Using the BEGe I have developed a quick and sensitive method to detect Plutonium
isotopes concentration in environmental samples through the detection of the X-rays emitted during their decays.
This result is a very important improvement in Plutonium detection for monitoring measurements since the counting methods commonly used are characterized by long measuring and sample treatments time.
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Vidal, Maria Rita. "Geoecology of landscapes: background and applicability for environmental planning in river course low Curu - Cearà - Brazil." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14794.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel Superior<br>A tese trata da anÃlise da dinÃmica do conjunto paisagÃstico como meio para o planejamento ambiental do uso e ocupaÃÃo da APA (Ãrea de ProteÃÃo Ambiental) do EstuÃrio do Rio Curu e seu entorno, situada no litoral Oeste do Estado do CearÃ. A inexistÃncia de planejamento ambiental e o desencontro entre a APA e as formas de usos nesse espaÃo delimitado, levou a tese a fazer a proposta de redefiniÃÃo dos limites da APA para que esta possa englobar ambientes importantes para o funcionamento das paisagens. Fazendo uso das concepÃÃes teÃrico-metodolÃgicas da geoecologia das paisagens, adotou-se a proposta de Rodriguez, Silva e Cavalcanti (2004), com Ãnfase na estrutura e funcionamento das paisagens. Como resultados tem-se a existÃncia de um mosaico de paisagem, com diferenÃas e particularidades especÃficas na sua estrutura geoecolÃgica. Na determinaÃÃo do estado, degradaÃÃo e situaÃÃo geoecolÃgica da APA, o estudo mostrou que apenas 20% das unidades geoecolÃgicas agrupam-se em estado ambiental estÃvel sem degradaÃÃes e com situaÃÃo geoecolÃgica favorÃvel. O restante das paisagens que compÃem a APA apresentou estado e situaÃÃo geoecolÃgica desfavorÃvel, o qual abarca 80% das paisagens estudadas, caracterizando condiÃÃes insatisfatÃrias para o cumprimento das funÃÃes ambientais dessas paisagens. Os usos e ocupaÃÃes na APA nÃo correspondem ao potencial do solo, e nÃo se observam formas de organizaÃÃo de uso que garantam a otimizaÃÃo do aproveitamento das propriedades fundamentais, das estruturas e das potencialidades das paisagens.<br>The thesis deals with the analysis of the dynamics of the landscape as a means for the environmental planning to use and occupate the APA (Environmental Protection Area) in the Estuary of Curu River and its surroundings, situated on the west coast of CearÃ.The lack of environmental planning and the mismatch between the APA and ways of using this limited space led to the thesis to raise the proposal of redefinition of the APA limits so that it can encompass important environments for the functioning of landscapes. Making use of theoretical and methodological concepts of geoecology of landscapes, we have adopted the proposal of Rodriguez, Silva and Cavalcanti (2004), who emphasize on the structure and functioning of landscapes. As a result there is the existence of a landscape mosaic, with differences and specific characteristics in its geoecological structure. In determining the state, degradation and geoecological situation of the APA, the study showed that only 20% of goecological units are grouped in stable environmental state without any degradation and in favorable geoecological situation. The rest of the landscapes that make up the APA had shown unfavorable state and geoecological situation, which covers 80% of the studied landscapes, featuring unsatisfactory conditions to meet the environmental functions of those landscapes. The uses and occupations in the APA do not correspond with ground potential, and we have not observed forms of organization of using to ensure the optimization of the employment of the fundamental properties, structures and potential of landscapes.
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Simons, Penelope C. "The philosophical background to the emergence of the idea of the individualised state in the international legal system." Thesis, University of Cambridge, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361671.
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Fischer, Felix Friedrich. "The regulation of Section 17 (2a) of the German Energy Economy Act against the background of current developments of the German and European offshore wind industry." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/5750.
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Thesis (MBA (Business Management))--Stellenbosch University, 2008.<br>ENGLISH ABSTRACT: With the introduction of Section 17 of the EnWG (German Energy Economy Act), the legislator created a new situation for the complex relationships in the German offshore wind industry. The transmission system operators are now obliged not only to provide the connection for offshore wind farms, but also to reimburse the developers of such plants for the costs they incurred in the course of planning the cable connection between the wind farm and the onshore grid. Forecasts had predicted that by 2007 numerous offshore wind farms would be operational. But no development company in the entire sector had moved beyond the planning phase. However, the rapid development of the offshore wind industry is important in order to achieve the German goal to generate 20% of all energy from renewable energy sources by 2020 and thus contribute to the prevention of grave climate changes. It is also important for the domestic labour market and the initiation of further exports of energy technologies. Early domestic growth will eventually payoff as offshore wind energy is implemented by more countries, which will then rely on the experience of German companies. Under these circumstances, Section 17 (2a) S.3 of the EnWG induces a positive impulse for offshore development. Under the financial constraints that dampened the expectations of developers of offshore wind farms, the suggested reimbursement will offer welcome relief. However a broad interpretation of Section 17 (2a) S.3 of the EnWG must be applied in order to reach the goal of actually enhancing offshore development, as is the legislator's intent. Such a broad interpretation of the reimbursement claim will lead to rapid implementation of the new law, as this will be in the interest of the developers and transmission system operators. The developers will have a large interest in beginning with the actual construction of the wind farm, and the transmission system operators will need to proceed with the planning of the cable connection. Even though improvements remain necessary the introduction of Section 17 (2a) S.3 EnWG can be considered a success.<br>AFRIKAANSE OPSOMMING: Met die inwerkingstelling van afdeling 17 van die EnGW (Duitse Energie Ekonomie Wet), het die regering 'n nuwe situasie geskep vir die komplekse verhouding in die Duitse see-gebonde wind-energie industrie. Die transmissie stelsel operateurs word nou verplig om nie net die verbinding met die wind-plaas te verskaf nie, maar moet ook die ontwikkelaar van die aanleg vergoed vir enige kostes wat hulle aangegaan het met die beplanning van die verbinding tussen die windplaas en die elektrisiteits-netwerk. Vooruitskattings het voorspel dat verskeie see-gebonde windplase operasioneel sou wees teen 2007. Geen ontwikkelingsmaatskappy het egter al tot dusver verder as die beplanningstadium gevorder nie. Desnieteenstaande, die spoedige ontwikkeling van die see-gebonde wind industrie is onontbeerlik in die Duitse mikpunt om 20% van energiebehoeftes op te wek vanuit hernubare bronne teen 2020 en om dus klimaatsverandering teen te werk. Dit is ook belangrik vir werkskepping in Duitsland en vir die uitvoer van energie tegnologie. Spoedige groei in die industrie sal uiteindelik dividende lewer soos seegebonde wind-energie deur ander lande ontwikkel word en gevolglik op Duitse ervaring moet staatmaak. Onder hierdie omstandighede het afdeling 17 (2a) 5.3 van die EnGW 'n positiewe effek op seegebonde ontwikkeling. As gevolg van die dempende effek wat finansiele beperkinge het op die verwagtinge van ontwikkelaars sal die terugbetalings welkome verligting bied. Dit is egter nodig om 'n bree interpretasie van afdeling 17 (2a) 5.3 van die EnGW te gebruik om die mikpunt van werklike bevordering van seegebonde ontwikkeling te bewerkstellig soos die wetgewer beoog. So 'n bree interpretasie sal lei tot spoedige implimentasie van die nuwe wet omdat dit in die belang van ontwikkelaars en transmissie-netwerk eienaars sal wees. Die ontwikkelaars sal baat daarby om spoedig met ontwikkeling te begin, terwyl die netwerk operateurs vordering sal moet maak met die beplanning van die kabel-verbinding. Ten spyte daarvan dat verdere verbeteringe nodig is kan die inwerkingstelling van afdeling 17 (2a) 5.3 van die EnGW as 'n sukses gereken word.
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Garti, Sara. "Spectrométrie gamma haute résolution et bas bruit Compton pour la détection des ruptures de gaine dans les réacteurs rapides refroidis au sodium." Thesis, Université Grenoble Alpes, 2020. https://tel.archives-ouvertes.fr/tel-02862768.
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Les réacteurs de quatrième génération sont développés dans le but de renouveler la filière énergétique du nucléaire avec des réacteurs plus sûrs, optimisant la consommation du minerai uranium et produisant moins de déchets de vie longue. La France a investi dans le développement de la technologie des réacteurs à neutrons rapides refroidis au sodium. Par le passé, des prototypes ont été construits et exploités tels que RAPSODIE, PHENIX, SUPERPHENIX ; et depuis 2006, le CEA est en charge de la conception du futur prototype de cette filière : ASTRID. C’est dans ce cadre que les équipes du Commissariat à l’énergie atomique travaillent sur l’élaboration de moyens instrumentaux permettant de garantir l’intégrité absolue de la première barrière de confinement : la gaine des aiguilles combustibles. En effet, le niveau de sûreté à atteindre dans le programme génération 4 oblige l’exploitant à surveiller en continu la propreté du fluide caloporteur primaire. Pour assurer cette fonction de sûreté, différents systèmes sont implémentés tels que les systèmes de détection des neutrons différés (DND) et les systèmes de spectrométrie gamma. Ces systèmes sont en continuelle mutation depuis leurs premières exploitations par des programmes R&D assurant la prise en compte du retour d’exploitation de ces instruments et la remise à niveau en regard des avancées technologiques et des nouveaux moyens numériques de conception. L’instrumentation historique pour le suivi isotopique des gaz de fission par spectrométrie gamma est très bruitée et est compromise par la présence de lignes à retard d’environ 15 minutes nécessaires à la désactivation du 23Ne (T1/2 =38 s). De plus, l’autre source de bruit, i.e. l’41Ar, présentant une période de 110 minutes, n’a pas été filtrée par cette instrumentation. En effet, ce dernier ne perd que 7% de son activité dans ces lignes à retard.Au regard des exigences de sûreté fixées pour les RNR-Na, nous étudierons dans le cadre de cette thèse l’apport potentiel d’une instrumentation bas bruit au moyen d’un système à suppression Compton intégré au poste de mesure RNR-Na. L’enjeu majeur d’une telle instrumentation serait, d’une part, d’enrichir le diagnostic par la détection des produits de fission de courte période (~3 min), lesquels peuvent signer précocement une mise en contact entre le combustible et le caloporteur dangereuse pour la sûreté du réacteur, d’autre part, d’assurer une détection rapide par l’amélioration du temps de réponse de la mesure.Dans un premier temps, le terme source des produits de fission a été caractérisé par la mise en équation des différents phénomènes physiques régissant le comportement des gaz de fission dans un environnement de type RNR-Na faisant suite à une rupture de gaine. Des activités attendues des produits de fission sont ainsi estimées. Dans un second temps, nous avons procédé à l’étude numérique, au moyen de la méthode Monte Carlo, d’une instrumentation bas bruit, à sa validation expérimentale, puis à son optimisation. Enfin, nous avons implémenté la modélisation de la mesure spectrométrique bas bruit pour la problématique des ruptures de gaine dans le cadre d’un environnement RNR-Na. Des activités minimales détectables de produits de fission sont, d’abord, calculées puis comparées aux activités attendues. La plus-value de cette instrumentation pour l’application à la détection précoce des pertes d’étanchéité dans un environnement type RNR-Na sera alors exposée<br>Fourth generation reactors are being developed for renewing the nuclear energy industry with safer reactors that optimize uranium resources and produce less long-lived radioactive waste. France has focused on the development of SFR “Sodium Fast Reactor”. In the past, prototypes have been built and operated such as Rapsodie, Phénix, Superphénix. Since 2006, the CEA (French Atomic Energy Commission) has overseen the design of the future prototype of this technology: ASTRID. It is within this framework that teams at the French Atomic Energy Commission are working on the development of instrumental means to guarantee the absolute integrity of the first containment barrier: the fuel cladding. Indeed, the safety level to be achieved in the fourth-generation program requires the operator to continuously monitor the fission products released into the primary coolant. To ensure this safety function, various systems were implemented, such as delayed neutron detection (DND) and gamma spectrometry systems. These systems have been upgraded since their first operations through R&D programs in line with technological advances and new digital design methods.The historical gamma spectrometry instrumentation for clad failure monitoring is compromised by the presence of significant background that leads to delay lines of about 15 minutes necessary for the 23Ne (T1/2 =38 s) decay. In addition, the other background source, i.e. 41Ar, with a half-life of 110 minutes, was not filtered by this instrumentation. Indeed, it loses only 7 % of its activity in these delay lines.Regarding the safety requirement set for SFR, we will study in the frame of this work the potential contribution of a low background instrumentation by means of a Compton suppression system integrated into the SFR measuring device. The main goal of such an instrumentation would be, first, to strengthen the diagnostic of the detection of short-period fission products (about 3 min) which could indicate an early contact between the fuel and the coolant that can be dangerous for the reactor safety, second, to ensure a fast detection by improving the measuring response time.First, the source term of fission products was characterized by putting into equation various physical phenomena that govern the behavior of fission gas in an SFR environment following a clad failure. Expected fission products activities have been estimated. Second, we performed a numerical study, by means of the Monte Carlo method, of a low background instrumentation, from its experimental validation to its optimization. Finally, we implemented the model for the problem of cladding failure in the case of SFR environment. Minimum detectable activities have been estimated then compared to expected activities. The added value of this instrumentation for applications to the early detection of clad failures in an SFR environment will then be exposed
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Elshazly, Amr. "Performance enhancement techniques for low power digital phase locked loops." Thesis, 2012. http://hdl.handle.net/1957/31116.
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Desire for low-power, high performance computing has been at core of the symbiotic union between digital circuits and CMOS scaling. While digital circuit performance improves with device scaling, analog circuits have not gained these benefits. As a result, it has become necessary to leverage increased digital circuit performance to mitigate analog circuit deficiencies in nanometer scale CMOS in order to realize world class analog solutions.
In this thesis, both circuit and system enhancement techniques to improve performance of clock generators are discussed. The following techniques were developed: (1) A digital PLL that employs an adaptive and highly efficient way to cancel the effect of supply noise, (2) a supply regulated DPLL that uses low power regulator and improves supply noise rejection, (3) a digital multiplying DLL that obviates the need for high-resolution TDC while achieving sub-picosecond jitter and excellent supply noise immunity, and (4) a high resolution TDC based on a switched ring oscillator, are presented. Measured results obtained from the prototype chips are presented to illustrate the proposed design techniques.<br>Graduation date: 2013<br>Access restricted to the OSU Community at author's request from July 16, 2012 - July 16, 2014
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Yang, Kuoching, and 楊國清. "The Impact of Litigation Experience, Legal Backgrounds and Present Law Satisfaction on the Attitude toward “The Public Trial Observation System”." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/98928182737700273621.
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碩士<br>國立中正大學<br>犯罪防治研究所<br>100<br>The purpose of this research is to understand whether the subjects’ litigation experiences, legal backgrounds and present law satisfactions influence their attitudes toward “The Public Trial Observation System”. The researcher adopted survey method to collect data and three kinds of scales were used in the research: “Attitudes toward contents of the public trial observation system”, “satisfaction of present law”, and” expectancy of the public trial observation system”. There were 343 effective samples collected in this research. The “Attitude toward contents of the public trial observation system” scale was processed by one-way ANOVA, while the other two scales were processed by MONOVA and path analysis. The author found that the subjects think the most trial scrutators’ opinion should be the important basis for the judgments and it’ll influence the scrutators making judge if they face the defendants directly. Moreover, the subjects worry that the trail scrutators may encounter danger. The analysis of Satisfaction of present law scale shows that subjects think the judges couldn’t fit to citizen’s expectation for they don’t understand public opinion clearly. Besides, the subjects even consider that present justice isn’t intelligible and transparent enough for the public. However, most subjects still have positive attitudes toward the justice and they’re willing to be the trial scrutators. The analysis of one-way ANOVA shows that gender, age, education, litigation experience, legal backgrounds and present law satisfaction indeed influence the people’s attitude toward the contents of public trial observation system. On the other hand, the subjects’ litigation experiences influence both their satisfaction of present law and expectancy of the public trial observation system through the MANOVA analysis. Furthermore, the subjects’ satisfactions of present law could have impact on their expectation to the Public Trial Observation System. At the end of this research, the author gave some suggestions to the public trial observation system and the future research.
Livres sur le sujet "Low Background systems"
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North Dakota. Legislative Assembly. Legislative Council. and North Dakota. Legislative Assembly. Legislative Council. Budget Committee on Institutional Services., eds. State emergency medical services system: Background memorandum. The Committee, 1987.
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Kruger, Lennard G. Broadband internet access: Background and issues. Congressional Research Service, Library of Congress, 2000.
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Gilroy, Angele A. Broadband internet access: Background and issues. Congressional Research Service, Library of Congress, 2003.
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Buckley, Melina. Perspectives on the civil justice system: A background paper prepared for the CBA Systems of Civil Justice Task Force. Canadian Bar Association, 1998.
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Stanford, Jay G. Implementing 9-1-1 systems in Texas: Legal and institutional background. The Commission, 1987.
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Porter, Donna Viola. A national nutrition monitoring system: Background and bill review. Congressional Research Service, Library of Congress, 1988.
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Federal/Provincial/Territorial Working Group of Attorneys General Officials on Gender Equality in the Canadian Justice System. Gender equality in the Canadian justice system: Background papers. Dept. of Justice, 1992.
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Porter, Donna Viola. A national nutrition monitoring system: Brief background and bill review. Congressional Research Service, Library of Congress, 1987.
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Porter, Donna Viola. A national nutrition monitoring system: Brief background and bill comparison. Congressional Research Service, Library of Congress, 1986.
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Office, General Accounting. Gun control: Options for improving the National Instant Criminal Background Check System : report to congressional requesters. The Office, 2000.
Trouver le texte intégralChapitres de livres sur le sujet "Low Background systems"
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Shafique, Muhammad, and Jörg Henkel. "Background and Related Work." In Hardware/Software Architectures for Low-Power Embedded Multimedia Systems. Springer New York, 2011. http://dx.doi.org/10.1007/978-1-4419-9692-3_2.
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Khan, Muhammad Umar Karim, and Chong-Min Kyung. "Poisson Mixture Model for High Speed and Low-Power Background Subtraction." In Smart Sensors and Systems. Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-42234-9_1.
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Yao, Dongxin, and Zhishuo Liu. "Research on Multimodal Transportation Path Optimization with Time Window Based on Ant Colony Algorithm in Low Carbon Background." In Green, Smart and Connected Transportation Systems. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-15-0644-4_77.
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Contini, Dalit, and Roberto Zotti. "Do Financial Conditions Play a Role in University Dropout? New Evidence from Administrative Data." In Teaching, Research and Academic Careers. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-07438-7_3.
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AbstractA large strand of research in the economics and sociology of education has highlighted the existence of deeply rooted inequalities in educational choices along socioeconomic lines, even when net of prior performance. These disparities may take different forms at different stages of schooling and across institutional systems. Yet, due to the lack of data, it is often difficult to disentangle the role played by the various dimensions of socioeconomic background on students’ educational careers. While parental education and occupation may shape aspirations (and thus the wish to undertake ambitious educational programmes), lack of income could represent a material obstacle to the continuation of study. In this chapter, we focus on the effect of financial conditions on the probability of dropping out from university. Italy is an interesting study case, because the education system is mainly public and university tuition fees are relatively low and income progressive. Because direct costs for disadvantaged students are low, we would expect income not to be highly relevant in this context. By exploiting a unique data set from the University of Torino (in northern Italy) linking administrative data from students’ university careers and information on parental characteristics collected at matriculation, we analyse how socioeconomic background influences the first-year dropout probability. While extremely relevant in earlier educational outcomes, parental education and occupation no longer exert a sizable effect at this point in students’ lives. Instead, we find that economic conditions greatly influence the chances of completing university. This result suggests that low tuition fees may be insufficient to foster the participation of low-income high school graduates and that additional forms of support might be needed to ensure equity and, at the same time, raise the share of young people with higher education degrees, which is still too low in Italy.
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Mäkelä, Marja-Liisa, and Mira Kalalahti. "Negotiated, Given and Self-Made Paths: Immigrant Origin Girls and Post-compulsory Educational Transition in Finland." In Finland’s Famous Education System. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8241-5_21.
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AbstractAlthough Finland still has a relatively low proportion of students with a migrant background, it has not been able to ensure that immigrants and their descendants have equal educational opportunities. Education could enhance integration but migrant backgrounds have a persistent impact. In this chapter, our focus is on post-comprehensive educational decision-making processes of immigrant origin adolescent girls, with the viewpoint of the multifaceted intertwinement of gender and ethnicity. We conceptualise the educational decisions as negotiations that adolescents have to have with their families, teachers, counsellors and peers. Within these negotiations, the negotiating parties try to push the adolescent to choose those educational paths they see valued and preferred, and away from the choices they see as unfitting or less valued. As the girls ‘negotiate their identities according to situational contexts’, their agency is constructed with ongoing and reflective negotiations with other people. In this chapter, we show how adolescent girls with an immigrant background in Finland face quite similar difficulties as ethnic minorities in other European and Nordic countries when continuing their education from compulsory education. We also illustrate with three ‘transitional stories’ the key challenges that girls with immigrant backgrounds encounter when making their educational decisions and integrating to education: structural boundaries, social boundaries and acculturation.
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Tomaszewski, Wojtek, Francisco Perales, Ning Xiang, and Matthias Kubler. "Differences in Higher Education Access, Participation and Outcomes by Socioeconomic Background: A Life Course Perspective." In Family Dynamics over the Life Course. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-12224-8_7.
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AbstractThe intergenerational transmission of socio-economic status is driven to a significant extent through parents with higher socio-economic status providing advantages to their children as they move through the education system. At the same time, attainment of higher education credentials constitutes an important pathway for upwards social mobility among individuals from low socio-economic family backgrounds. Given the critical importance of higher education for socio-economic outcomes of children, this chapter focuses on young people’s journeys into and out of university. Drawing on the life course approach and opportunity pluralism theory, we present a conceptual model of the university student life cycle that splits individuals’ higher education trajectories into three distinct stages: access, participation and post-participation. Using this model as a guiding framework, we present a body of recent Australian evidence on differences in pathways through the higher education system among individuals from low and high socio-economic status (SES) backgrounds. In doing so, we pay attention to factors such as family material circumstances, students’ school experiences and post-school plans, and parental education and expectations—all of which constitute important barriers to access, participation and successful transitions out of higher education for low SES students. Overall, our results indicate that socio-economic background plays a significant role in shaping outcomes at various points of individual’s educational trajectories. This is manifested by lower chances amongst low-SES individuals to access and participate in higher education, and to find satisfying and secure employment post-graduation. Our findings bear important implications for educational and social policy.
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Sevanthi, Amitha Mithra V., Prashant Kale, Chandra Prakash, et al. "National repository of EMS induced mutants of an upland rice cultivar Nagina 22: progress update on characterization and utilization." In Mutation breeding, genetic diversity and crop adaptation to climate change. CABI, 2021. http://dx.doi.org/10.1079/9781789249095.0030.
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Abstract The Indian initiative for creating mutant resources in rice has generated 87,000 mutants in the background of a popular drought- and heat-tolerant upland cultivar, Nagina 22 (N22), through EMS mutagenesis. So far, 541 macro-mutants from this resource have been identified, maintained in the mutant garden and characterized in detail based on 44 descriptors pertaining to distinctness, uniformity and stability (DUS) of rice and other agronomic parameters. The similarity index of the mutants was more than 0.6 for nearly 90% of the mutants with respect to DUS descriptors, further establishing the validity of the mutants. The available high-quality sequence resource of N22 has been improved by reducing the gaps by 0.02% in the coding sequence (CDS) region. This was made possible using the newly synthesized whole-genome data of N22 which helped to remove 9006 'Ns' and replace 12,746 existing nucleotides with the accurate ones. These sequence and morphological details have been updated in the mutant database 'EMSgardeN22'. Further, 1058 mutants have been identified for low-P tolerance, tolerance to sheath blight, blast, drought, heat, higher photosynthetic efficiency and agronomic and root traits from this resource. A novel herbicide-tolerant (imazethapyr) mutant earlier identified and characterized from this resource is now being used in introgressing the herbicide-tolerant trait in eight major rice varieties in India. Further, robust and simpler screening systems have been tested for studying low-P tolerance of the mutants. A grain-size mutant, heat-tolerant mutant, drought-tolerant mutant, stay-green mutant and low-P tolerant and water-use efficient high-root-volume mutants have been characterized at morphological and molecular levels. A brief account of all these mutants, the entire mutant resource and the elaborate trait-based screenings is presented in this chapter.
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Järvinen, Tero, Jenni Tikkanen, and Piia af Ursin. "The Significance of Socioeconomic Background for the Educational Dispositions and Aspirations of Finnish School Leavers." In Finland’s Famous Education System. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-8241-5_15.
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AbstractThis chapter examines the significance of socioeconomic background (SES) for the educational dispositions and aspirations of Finnish comprehensive school leavers. After demonstrating the existence of the relationship between the students’ SES background and their dispositions and aspirations, the main question addressed is whether this relationship changes when controlling for the effect of students’ academic ability as measured by their literacy skills. In our examination, we draw on a study of 15-year-old lower secondary school students (n = 1058) in Turku sub-region consisting of the city of Turku and ten smaller, surrounding municipalities. The results of our study are mixed. Students with high-level literacy skills have positive dispositions towards learning and education despite their socioeconomic background. The same is, however, not the case with educational aspirations. Among low-SES students, individual ability does not predict high educational aspirations in a similar manner that it does among high-SES students. This finding poses a challenge for the Finnish education system. If SES is a more significant predictor of educational aspirations of an individual than ability or motivation, there are negative effects for both individuals themselves and society. From the individual point of view, self-exclusion of gifted low-SES students from higher education decreases their future labour market opportunities and outcomes. From the societal point of view, in turn, it means that many occupational fields will lose potentially talented and skilful employees. In these respects, the Finnish education system would not only be unequal but also inefficient.
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Divac, Una, Maurilio Felici, Nina Kršljanin, Pietro Lo Iacono, and Vojislav Stanimirović. "Gender Issues in Comparative Legal History." In Gender-Competent Legal Education. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-14360-1_2.
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AbstractThis chapter analyses the key gender issues throughout comparative legal history, from the Antiquity to the contemporary era. A wide array of subjects will be briefly touched upon, such as the traditional roles of men and women and their legal recognition, the legal status of women, the patriarchal patterns and the trends of their change, the interaction of religion and law in these areas. These various subjects all portray a millennia-long domination of the patriarchal system and the long and arduous struggle for gender equality. The text is mainly concerned with the Western legal systems, broadly speaking—European, Near-Eastern and American—showcasing individual legal systems in the Antiquity and Middle Ages, where differences during these times were greater, but focusing instead on key issues and areas of law in the Modern era, where convergence and common tendencies become more pronounced. By understanding these issues in their historical context, readers will gain valuable knowledge of the historical background of the current status of gender relations in the main legal systems of the world.
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Xie, Feifei, and Xuemei Li. "A Study of Vehicle Tax Policy Adjustment Based on System Dynamics in the Background of Low-Carbon Transport." In LTLGB 2012. Springer Berlin Heidelberg, 2013. http://dx.doi.org/10.1007/978-3-642-34651-4_20.
Texte intégralActes de conférences sur le sujet "Low Background systems"
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Khalil, Mahmoud A., Emad Hegazi, and Mohamed El-Nozahi. "Low-ripple PFM Buck Converter Employing Background Calibration." In 2018 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE, 2018. http://dx.doi.org/10.1109/iscas.2018.8351256.
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Peng, Xizhu, Jinfeng Guo, Qingqing Bao, Zeyu Li, Haoyu Zhuang, and He Tang. "A Low-Power Low-Cost On-Chip Digital Background Calibration for Pipelined ADCs." In 2020 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE, 2020. http://dx.doi.org/10.1109/iscas45731.2020.9180989.
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Fouks, Boris I. "Active modes of operation of low-background extrinsic IR detectors." In Fifth Conference on Charge-Coupled Devices and CCD Systems, edited by Vladimir A. Karasev, Yuri A. Kuznetsov, and Victor A. Shilin. SPIE, 1996. http://dx.doi.org/10.1117/12.238220.
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Shoaib, Muhammad, Tobias Elbrandt, Evgeny Zaretskiy, and Joern Ostermann. "Hierarchical Bayer-pattern based background subtraction for low resource devices." In 2012 IEEE International Symposium on Circuits and Systems - ISCAS 2012. IEEE, 2012. http://dx.doi.org/10.1109/iscas.2012.6271634.
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Jovancevic, N., M. Krmar, I. Bikit, et al. "Study of Neutron Induced Activity in Low-Background Gamma Spectroscopy Systems." In NUCLEAR STRUCTURE AND DYNAMICS ’09: Proceedings of the International Conference. AIP, 2009. http://dx.doi.org/10.1063/1.3232147.
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Narasimman, Neelakantan, and Tony T. Kim. "An ultra-low voltage, VCO-based ADC with digital background calibration." In 2016 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE, 2016. http://dx.doi.org/10.1109/iscas.2016.7527532.
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Zou, Yu, Massimo Gottardi, and Matteo Perenzoni. "Live Demostration: Low Power Vision Sensor with Robust Dynamic Background Rejection." In 2018 IEEE International Symposium on Circuits and Systems (ISCAS). IEEE, 2018. http://dx.doi.org/10.1109/iscas.2018.8351881.
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Tabkhi, Hamed, Majid Sabbagh, and Gunar Schirner. "An efficient architecture solution for low-power real-time background subtraction." In 2015 IEEE 26th International Conference on Application-specific Systems, Architectures and Processors (ASAP). IEEE, 2015. http://dx.doi.org/10.1109/asap.2015.7245737.
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Poehler, Jeffrey C., Gary L. Stevens, Anees A. Udyawar, and Amy Freed. "Background on Low Temperature Overpressure Protection System Setpoints for Pressure-Temperature Curves." In ASME 2020 Pressure Vessels & Piping Conference. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/pvp2020-21663.
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Abstract ASME Code, Section XI, Nonmandatory Appendix G (ASME-G) provides a methodology for determining pressure and temperature (P-T) limits to prevent non-ductile failure of nuclear reactor pressure vessels (RPVs). Low-Temperature Overpressure Protection (LTOP) refers to systems in nuclear power plants that are designed to prevent inadvertent challenges to the established P-T limits due to operational events such as unexpected mass or temperature additions to the reactor coolant system (RCS). These systems were generally added to commercial nuclear power plants in the 1970s and 1980s to address regulatory concerns related to LTOP events. LTOP systems typically limit the allowable system pressure to below a certain value during plant operation below the LTOP system enabling temperature. Major overpressurization of the RCS, if combined with a critical size crack, could result in a brittle failure of the RPV. Failure of the RPV could make it impossible to provide adequate coolant to the reactor core and result in a major core damage or core melt accident. This issue affected the design and operation of all pressurized water reactors (PWRs). This paper provides a description of an investigation and technical evaluation regarding LTOP setpoints that was performed to review the basis of ASME-G, Paragraph G-2215, “Allowable Pressure,” which includes provisions to address pressure and temperature limitations in the development of P-T curves that incorporate LTOP limits. First, high-level summaries of the LTOP issue and its resolution are provided. LTOP was a significant issue for pressurized water reactors (PWRs) starting in the 1970s, and there are many reports available within the U.S. Nuclear Regulatory Commission’s (NRC’s) documentation system for this topic, including Information Notices, Generic Letters, and NUREGs. Second, a particular aspect of LTOP as related to ASME-G requirements for LTOP is discussed. Lastly, a basis is provided to update Appendix G-2215 to state that LTOP setpoints are based on isothermal (steady-state) conditions. This paper was developed as part of a larger effort to document the technical bases behind ASME-G.
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Golubnichyi, P. I., A. D. Philonenko, A. A. Tsaric, et al. "Recording of neutron and acoustic emissions from palladium target in a low background underground experiment." In Anomalous nuclear effects in deuterium/solid systems. AIP, 1991. http://dx.doi.org/10.1063/1.40715.
Texte intégralRapports d'organisations sur le sujet "Low Background systems"
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Runkle, Robert C., Craig E. Aalseth, Vanessa L. Bailey, et al. Opportunities for Decay Counting of Environmental Radioisotopes Using Ultra-low-background Detection Systems. Office of Scientific and Technical Information (OSTI), 2012. http://dx.doi.org/10.2172/1060139.
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Dunbar, Joseph. Vertical and horizontal datums used in the Lower Mississippi Valley for US Army Corps of Engineers projects. Engineer Research and Development Center (U.S.), 2022. http://dx.doi.org/10.21079/11681/42781.
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Six geodetic datums have been used by the US Army Corps of Engineers (USACE), Mississippi River Commission (MRC), for river surveys in the Lower Mississippi Valley (LMV). These legacy elevation datums are the Cairo datum, the Memphis datum, the Mean Gulf Level (MGL), the Mean Sea Level (MSL), the National Geodetic Vertical Datum (NGVD) 1929, and the North American Vertical Datum 1988 (NAVD88). The official geodetic datum currently prescribed by the USACE is NAVD88 (USACE 2010). In addition to these different geodetic datums, hydraulic datums are in use by the USACE for rivers, lakes, and reservoir systems. Hydrographic surveys from the Mississippi River are typically based on a low water pool or discharge reference, such as a low water reference plane (LWRP), an average low water plane (ALWP), or a low water (LW) plane. The following technical note is intended to provide background information about legacy datums used in the LMV to permit comparison of historic maps, charts, and surveys pertaining to the Mississippi River in the LMV. The purpose of this report is to provide background information and history of different published horizontal and vertical datums used for presentation of hydrographic survey data from the Mississippi River. The goal is to facilitate understanding of differences with comparison to other historic surveys for change-detection studies along the river. Conversion values are identified herein for the earlier surveys where appropriate, and methods are presented here to evaluate the differences between earlier and later charts and maps. This report is solely intended to address the LMV area and historic surveys made there. This note is not applicable to areas outside of the LMV. Throughout this technical note, historic hydrographic surveys and data from the Memphis, TN, to Rosedale, MS, reach will be used as examples of features of interest for discussion purposes. Selected historic hydrographic survey sheets at Helena, AR, are included as Plates 1 to 3 (Appendix C) of this document and will be used as examples for discussion purposes.
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Douglas, D. G., R. F. Wise, J. W. Starr, and J. W. Jr Maresca. Leak testing plan for the Oak Ridge National Laboratory liquid low-level waste systems (active tanks): Revision 2. Volume 1: Regulatory background and plan approach; Volume 2: Methods, protocols, and schedules; Volume 3: Evaluation of the ORNL/LT-823DP differential pressure leak detection method; Appendix to Revision 2: DOE/EPA/TDEC correspondence. Office of Scientific and Technical Information (OSTI), 1994. http://dx.doi.org/10.2172/34317.
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Clevenger, Anthony P., and Adam T. Ford. A before-after-control-impact study of wildlife fencing along a highway in the Canadian Rocky Mountains. Nevada Department of Transportation, 2022. http://dx.doi.org/10.15788/ndot2022.02.
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Wildlife exclusion fencing has become a standard component of highway mitigation systems designing to reduce collisions with large mammals. Past work on the effectiveness of exclusion fencing has relied heavily on control-impact (i.e., space-for-time substitutions) and before-after study designs. These designs limit inference and may confound the effectiveness of mitigation with co-occurring process that also change the rate of collisions. We used a replicated before-after-control-impact study design to assess fencing effectiveness along the Trans-Canada Highway in the Rocky Mountains of Canada. We found that collisions declined for common ungulates species (elk, mule deer and white-tailed deer) by up to 96% but not for large carnivores. The weak response of carnivores is likely due to combination of fence intrusions and low sample sizes. When accounting for background changes in collision rates observed at control sites, naïve estimates of fencing effectiveness declined by 6% at one site to 90% and increased by 10% at another to a realized effectiveness of 82%. When factoring in the cost of ungulate collisions to society as a whole, fencing provided a net economic gain within 1 year of construction. Over a 10-year period, fencing would provide a net economic gain of >$500,000 per km in reduced collisions. In contrast, control site may take upwards of 90 years before the background rates of collisions decline to a break even point. Our study highlights the benefits of long-term monitoring of road mitigation projects and provides evidence of fencing effectiveness for reducing wildlife-vehicle collisions involving large mammals.
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Cahaner, Avigdor, Susan J. Lamont, E. Dan Heller, and Jossi Hillel. Molecular Genetic Dissection of Complex Immunocompetence Traits in Broilers. United States Department of Agriculture, 2003. http://dx.doi.org/10.32747/2003.7586461.bard.
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Objectives: (1) Evaluate Immunocompetence-OTL-containing Chromosomal Regions (ICRs), marked by microsatellites or candidate genes, for magnitude of direct effect and for contribution to relationships among multiple immunocompetence, disease-resistance, and growth traits, in order to estimate epistatic and pleiotropic effects and to predict the potential breeding applications of such markers. (2) Evaluate the interaction of the ICRs with genetic backgrounds from multiple sources and of multiple levels of genetic variation, in order to predict the general applicability of molecular genetic markers across widely varied populations. Background: Diseases cause substantial economic losses to animal producers. Emerging pathogens, vaccine failures and intense management systems increase the impact of diseases on animal production. Moreover, zoonotic pathogens are a threat to human food safety when microbiological contamination of animal products occurs. Consumers are increasingly concerned about drug residues and antibiotic- resistant pathogens derived from animal products. The project used contemporary scientific technologies to investigate the genetics of chicken resistance to infectious disease. Genetic enhancement of the innate resistance of chicken populations provides a sustainable and ecologically sound approach to reduce microbial loads in agricultural populations. In turn, animals will be produced more efficiently with less need for drug treatment and will pose less of a potential food-safety hazard. Major achievements, conclusions and implications:. The PI and co-PIs had developed a refined research plan, aiming at the original but more focused objectives, that could be well-accomplished with the reduced awarded support. The successful conduct of that research over the past four years has yielded substantial new information about the genes and genetic markers that are associated with response to two important poultry pathogens, Salmonella enteritidis (SE) and Escherichia coli (EC), about variation of immunocompetence genes in poultry, about relationships of traits of immune response and production, and about interaction of genes with environment and with other genes and genetic background. The current BARD work has generated a base of knowledge and expertise regarding the genetic variation underlying the traits of immunocompetence and disease resistance. In addition, unique genetic resource populations of chickens have been established in the course of the current project, and they are essential for continued projects. The US laboratory has made considerable progress in studies of the genetics of resistance to SE. Microsatellite-marked chromosomal regions and several specific genes were linked to SE vaccine response or bacterial burden and the important phenomenon of gene interaction was identified in this system. In total, these studies demonstrate the role of genetics in SE response, the utility of the existing resource population, and the expertise of the research group in conducting such experiments. The Israeli laboratories had showed that the lines developed by selection for high or low level of antibody (Ab) response to EC differ similarly in Ab response to several other viral and bacterial pathogens, indicating the existence of a genetic control of general capacity of Ab response in young broilers. It was also found that the 10w-Ab line has developed, possibly via compensatory "natural" selection, higher cellular immune response. At the DNA levels, markers supposedly linked to immune response were identified, as well as SNP in the MHC, a candidate gene responsible for genetic differences in immunocompetence of chickens.
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Berkman, Nancy D., Eva Chang, Julie Seibert, et al. Management of High-Need, High-Cost Patients: A “Best Fit” Framework Synthesis, Realist Review, and Systematic Review. Agency for Healthcare Research and Quality (AHRQ), 2021. http://dx.doi.org/10.23970/ahrqepccer246.
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Background. In the United States, patients referred to as high-need, high-cost (HNHC) constitute a very small percentage of the patient population but account for a disproportionally high level of healthcare use and cost. Payers, health systems, and providers would like to improve the quality of care and health outcomes for HNHC patients and reduce their costly use of potentially preventable or modifiable healthcare services, including emergency department (ED) and hospital visits. Methods. We assessed evidence of criteria that identify HNHC patients (best fit framework synthesis); developed program theories on the relationship among contexts, mechanisms, and outcomes of interventions intended to change HNHC patient behaviors (realist review); and assessed the effectiveness of interventions (systematic review). We searched databases, gray literature, and other sources for evidence available from January 1, 2000, to March 4, 2021. We included quantitative and qualitative studies of HNHC patients (high healthcare use or cost) age 18 and over who received intervention services in a variety of settings. Results. We included 110 studies (117 articles). Consistent with our best fit framework, characteristics associated with HNHC include patient chronic clinical conditions, behavioral health factors including depression and substance use disorder, and social risk factors including homelessness and poverty. We also identified prior healthcare use and race as important predictors. We found limited evidence of approaches for distinguishing potentially preventable or modifiable high use from all high use. To understand how and why interventions work, we developed three program theories in our realist review that explain (1) targeting HNHC patients, (2) engaging HNHC patients, and (3) engaging care providers in these interventions. Theories identify the need for individualizing and tailoring services for HNHC patients and the importance of building trusting relationships. For our systematic review, we categorized evidence based on primary setting. We found that ED-, primary care–, and home-based care models result in reduced use of healthcare services (moderate to low strength of evidence [SOE]); ED, ambulatory intensive caring unit, and primary care-based models result in reduced costs (low SOE); and system-level transformation and telephonic/mail models do not result in changes in use or costs (low SOE). Conclusions. Patient characteristics can be used to identify patients who are potentially HNHC. Evidence focusing specifically on potentially preventable or modifiable high use was limited. Based on our program theories, we conclude that individualized and tailored patient engagement and resources to support care providers are critical to the success of interventions. Although we found evidence of intervention effectiveness in relation to cost and use, the studies identified in this review reported little information for determining why individual programs work, for whom, and when.
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Beckett-Brown, C. E., A. M. McDonald, and M. B. McClenaghan. Discovering a porphyry deposit using tourmaline: a case study from Yukon. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331349.
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As the exploration for porphyry Cu-Au-Mo deposits has become increasingly challenging, the development of more effective techniques directed at detecting buried deposits has become critical. One methodology is to focus on key minerals, one of which is tourmaline, a robust, ubiquitous mineral in most mineralized porphyry systems. Overall, a combination of physical and chemical characteristics including 1) macro-color, 2) morphology, 3) inclusion populations, and 4) trace-element compositions are useful in discriminating between porphyry- versus non-porphyry-derived (or related) tourmaline in surficial sediments (Beckett-Brown 2022). These features are applied to tourmaline obtained from stream sediment samples (n = 22) from 16 streams derived from the unglaciated terrain proximal to the Casino calc-alkaline porphyry Cu-Au-Mo deposit (Yukon Territory, Canada). The obtained tourmaline occurs as two distinct morphologies: 1) individual blocky to prismatic sub- to euhedral grains (Type 1), 2) aggregates of radiating prismatic to acicular sub- to euhedral grains (Type 2). Type 1 grains display trace-element contents that reflect mixed origins including a mineralized porphyry origin as well metamorphic and pegmatitic (background) environments. Type 2 grains almost exclusively exhibit porphyry-derived trace-element chemistries (i.e., high Sr/Pb ~150 avg. and relatively low Zn/Cu ~2.5 avg. values). In Canadian Creek, that directly drains from the Casino deposit, samples closest to the deposit contain &amp;gt;70% porphyry-derived tourmaline, while other streams in the region from unprospective drainage basins contain no porphyry-derived tourmaline. At the most distal sample site in Canadian Creek, ~20 km downstream from Casino, nearly 30% of the recovered tourmaline in the stream sediments is porphyry-related. This method has potential to be a strong indicator of prospectivity and applicable for exploration for porphyry Cu-Au-Mo systems in both unglaciated and glaciated terrains.
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Norelli, John L., Moshe Flaishman, Herb Aldwinckle, and David Gidoni. Regulated expression of site-specific DNA recombination for precision genetic engineering of apple. United States Department of Agriculture, 2005. http://dx.doi.org/10.32747/2005.7587214.bard.
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Objectives: The original objectives of this project were to: 1) evaluate inducible promoters for the expression of recombinase in apple (USDA-ARS); 2) develop alternative selectable markers for use in apple to facilitate the positive selection of gene excision by recombinase (Cornell University); 3) compare the activity of three different recombinase systems (Cre/lox, FLP/FRT, and R/RS)in apple using a rapid transient assay (ARO); and 4) evaluate the use of recombinase systems in apple using the best promoters, selectable markers and recombinase systems identified in 1, 2 and 3 above (Collaboratively). Objective 2 was revised from the development alternative selectable markers, to the development of a marker-free selection system for apple. This change in approach was taken due to the inefficiency of the alternative markers initially evaluated in apple, phosphomannose-isomerase and 2-deoxyglucose-6-phosphate phosphatase, and the regulatory advantages of a marker-free system. Objective 3 was revised to focus primarily on the FLP/FRT recombinase system, due to the initial success obtained with this recombinase system. Based upon cooperation between researchers (see Achievements below), research to evaluate the use of the FLP recombinase system under light-inducible expression in apple was then conducted at the ARO (Objective 4). Background: Genomic research and genetic engineering have tremendous potential to enhance crop performance, improve food quality and increase farm profits. However, implementing the knowledge of genomics through genetically engineered fruit crops has many hurdles to be overcome before it can become a reality in the orchard. Among the most important hurdles are consumer concerns regarding the safety of transgenics and the impact this may have on marketing. The goal of this project was to develop plant transformation technologies to mitigate these concerns. Major achievements: Our results indicate activity of the FLP\FRTsite-specific recombination system for the first time in apple, and additionally, we show light- inducible activation of the recombinase in trees. Initial selection of apple transformation events is conducted under dark conditions, and tissue cultures are then moved to light conditions to promote marker excision and plant development. As trees are perennial and - cross-fertilization is not practical, the light-induced FLP-mediated recombination approach shown here provides an alternative to previously reported chemically induced recombinase approaches. In addition, a method was developed to transform apple without the use of herbicide or antibiotic resistance marker genes (marker free). Both light and chemically inducible promoters were developed to allow controlled gene expression in fruit crops. Implications: The research supported by this grant has demonstrated the feasibility of "marker excision" and "marker free" transformation technologies in apple. The use of these safer technologies for the genetic enhancement of apple varieties and rootstocks for various traits will serve to mitigate many of the consumer and environmental concerns facing the commercialization of these improved varieties.
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Willits, Daniel H., Meir Teitel, Josef Tanny, Mary M. Peet, Shabtai Cohen, and Eli Matan. Comparing the performance of naturally ventilated and fan-ventilated greenhouses. United States Department of Agriculture, 2006. http://dx.doi.org/10.32747/2006.7586542.bard.
Texte intégralRésumé :
The objectives of this project were to predict the performance of naturally and fan-ventilated greenhouses as a function of climate, type of crop, evaporative cooling and greenhouse size, and to estimate the effects of the two cooling systems on yield, quality and disease development in the different crops under study. Background In the competitive field of greenhouse cultivation, growers and designers in both the US and Israel are repeatedly forced to choose between naturally ventilated (NV) and fan ventilated (FV) cooling systems as they expand their ranges in an effort to remain profitable. The known advantages and disadvantages of each system do not presently allow a clear decision. Whether essentially zero operating costs can offset the less dependable cooling of natural ventilation systems is question this report hopes to answer. Major Conclusions US It was concluded very early on that FV greenhouses without evaporative pad cooling are not competitive with NV greenhouses during hot weather. During the first year, the US team found that average air temperatures were always higher in the FV houses, compared to the NV houses, when evaporative pad cooling was not used, regardless of ventilation rate in the FV houses or the vent configuration in the NV houses. Canopy temperatures were also higher in the FV ventilated houses when three vents were used in the NV houses. A second major conclusion was that the US team found that low pressure fogging (4 atm) in NV houses does not completely offset the advantage of evaporative pad cooling in FV houses. High pressure fog (65 atm) is more effective, but considerably more expensive. Israel Experiments were done with roses in the years 2003-2005 and with tomatoes in 2005. Three modes of natural ventilation (roof, side and side + roof openings) were compared with a fan-ventilated (with evaporative cooling) house. It was shown that under common practice of fan ventilation, during summer, the ventilation rate is usually lower with NV than with FV. The microclimate under both NV and FV was not homogeneous. In both treatments there were strong gradients in temperature and humidity in the vertical direction. In addition, there were gradients that developed in horizontal planes in a direction parallel to the direction of the prevailing air velocity within the greenhouse. The gradients in the horizontal direction appear to be larger with FV than with NV. The ratio between sensible and latent heat fluxes (Bowen ratio) was found to be dependent considerably on whether NV or FV is applied. This ratio was generally negative in the naturally ventilated house (about -0.14) and positive in the fan ventilated one (about 0.19). Theoretical models based on Penman-Monteith equation were used to predict the interior air and crop temperatures and the transpiration rate with NV. Good agreement between the model and experimental results was obtained with regard to the air temperature and transpiration with side and side + roof ventilation. However, the agreement was poor with only roof ventilation. The yield (number of rose stems longer than 40 cm) was higher with FV
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Tipton, Kelley, Brian F. Leas, Nikhil K. Mull, et al. Interventions To Decrease Hospital Length of Stay. Agency for Healthcare Research and Quality (AHRQ), 2021. http://dx.doi.org/10.23970/ahrqepctb40.
Texte intégralRésumé :
Background. Timely discharge of hospitalized patients can prevent patient harm, improve patient satisfaction and quality of life, and reduce costs. Numerous strategies have been tested to improve the efficiency and safety of patient recovery and discharge, but hospitals continue to face challenges. Purpose. This Technical Brief aimed to identify and synthesize current knowledge and emerging concepts regarding systematic strategies that hospitals and health systems can implement to reduce length of stay (LOS), with emphasis on medically complex or vulnerable patients at high risk for prolonged LOS due to clinical, social, or economic barriers to timely discharge. Methods. We conducted a structured search for published and unpublished studies and conducted interviews with Key Informants representing vulnerable patients, hospitals, health systems, and clinicians. The interviews provided guidance on our research protocol, search strategy, and analysis. Due to the large and diverse evidence base, we limited our evaluation to systematic reviews of interventions to decrease hospital LOS for patients at potentially higher risk for delayed discharge; primary research studies were not included, and searches were restricted to reviews published since 2010. We cataloged the characteristics of relevant interventions and assessed evidence of their effectiveness. Findings. Our searches yielded 4,364 potential studies. After screening, we included 19 systematic reviews reported in 20 articles. The reviews described eight strategies for reducing LOS: discharge planning; geriatric assessment or consultation; medication management; clinical pathways; inter- or multidisciplinary care; case management; hospitalist services; and telehealth. All reviews included adult patients, and two reviews also included children. Interventions were frequently designed for older (often frail) patients or patients with chronic illness. One review included pregnant women at high risk for premature delivery. No reviews focused on factors linking patient vulnerability with social determinants of health. The reviews reported few details about hospital setting, context, or resources associated with the interventions studied. Evidence for effectiveness of interventions was generally not robust and often inconsistent—for example, we identified six reviews of discharge planning; three found no effect on LOS, two found LOS decreased, and one reported an increase. Many reviews also reported patient readmission rates and mortality but with similarly inconsistent results. Conclusions. A broad range of strategies have been employed to reduce LOS, but rigorous systematic reviews have not consistently demonstrated effectiveness within medically complex, high-risk, and vulnerable populations. Health system leaders, researchers, and policymakers must collaborate to address these needs.