250 research outputs found
Noncommutative Geometry and Symplectic Field Theory
In this work we study representations of the Poincare group defined over
symplectic manifolds, deriving the Klein-Gordon and the Dirac equation in phase
space. The formalism is associated with relativistic Wigner functions; the
Noether theorem is derived in phase space and an interacting field, including a
gauge field, approach is discussed.Comment: To appear in Physics Letters
Non-linear Liouville and Shr\"odinger equations in phase space
Unitary representations of the Galilei group are studied in phase space, in
order to describe classical and quantum systems. Conditions to write in general
form the generator of time translation and Lagrangians in phase space are then
established. In the classical case, Galilean invariance provides conditions for
writing the Liouville operator and Lagrangian for non-linear systems. We
analyze, as an example, a generalized kinetic equation where the collision term
is local and non-linear. The quantum counter-part of such unitary
representations are developed by using the Moyal (or star) product. Then a
non-linear Schr\"odinger equation in phase space is derived and analyzed. In
this case, an association with the Wigner formalism is established, which
provides a physical interpretation for the formalism
Multi-Strategy <em>MAX-MIN</em> Ant System for Solving Quota Traveling Salesman Problem with Passengers, Incomplete Ride and Collection Time
This study proposes a novel adaptation of MAX-MIN Ant System algorithm for the Quota Traveling Salesman Problem with Passengers, Incomplete Ride, and Collection Time. There are different types of decisions to solve this problem: satisfaction of the minimum quota, acceptance of ride requests, and minimization of travel costs under the viewpoint of the salesman. The Algorithmic components proposed regards vehicle capacity, travel time, passenger limitations, and a penalty for delivering a passenger deliverance out of the required destination. The ant-based algorithm incorporates different sources of heuristic information for the ants and memory-based principles. Computational results are reported, showing the effectiveness of this ant-based algorithm
Biofertilizante agrobio: Uma alternativa no controle da mancha bacteriana em mudas de pimentão (Capsicum annuum l.)
Agrobio é um biofertilizante líquido fabricado à base de esterco bovino, água, melaço e sais minerais, que são submetidos a um processo de fermentação à temperatura ambiente por 56 dias em recipientes abertos. Este produto tem sido largamente utilizado com sucesso por agricultores orgânicos e convencionais em todo o estado do Rio de Janeiro, no controle de várias enfermidades vegetais em diferentes culturas. Em bioensaios realizados em casa de vegetação, observou-se uma ação bacteriostática equivalente a de produtos químicos comerciais contra Xanthomonas campestris pv. vesicatoria em mudas de pimentão (Capsicum annuum L.), numa concentração de 5%. Nos bioensaios in vitro, onde foram testadas as concentrações de 2, 5 10 e 50% do Agrobio comercial, observouse que, a partir da concentração de 5%, ocorreu um nível satisfatório de inibição do crescimento bacteriano, apesar deste ter sido inferior ao obtido com o uso de sulfato de cobre e sulfato
de estreptomicina
Quality control in blood irradiation
Irradiation is a technique used in hemotherapy to functionally inactivateviable lymphocytes, in cellular blood components, to reduce the risk of Transfusion-associated Graft-versus-Host Disease (AT-GVHD), is rare but letal. One way to avoid it is to irradiate blood componentes in situations such as: intrauterine transfusion, newborns, patients receiving immunosuppressive therapy in bone marrow transplantation. Thus, it is extremely important that blood component is irradiated and, above all, ensure that the minimum dose is 25 Gy.The blood policy in Brazil is implemented through laws and normative decrees, giving rise to a legal system that underpins the actions of hemotherapy services. In order to correct verify absorbed doses and the quality assurance process as well as the safety for the irradiator operators we describe in this paper a several of physical measurements that is mandatory to support a physicist to evaluate the quality assurance during and after the irradiation process. The results obtained from this physical measurements provided a guarantee of proper radiation dose used in hemotherapy as well as methods and procedures applied to protect the patient, employees and general public due to procedure of blood irradiation accordling the Technical Regulation of Hemotherapy Procedures of the National Health Surveillance Agency (ANVISA) and safety regulations by National Nuclear Energy Commission (CNEN)
Palaeoecological data indicates land-use changes across Europe linked to spatial heterogeneity in mortality during the Black Death pandemic
The Black Death (1347-1352 CE) is the most renowned pandemic in human history, believed by many to have killed half of Europe's population. However, despite advances in ancient DNA research that conclusively identified the pandemic's causative agent (bacterium Yersinia pestis), our knowledge of the Black Death remains limited, based primarily on qualitative remarks in medieval written sources available for some areas of Western Europe. Here, we remedy this situation by applying a pioneering new approach, 'big data palaeoecology', which, starting from palynological data, evaluates the scale of the Black Death's mortality on a regional scale across Europe. We collected pollen data on landscape change from 261 radiocarbon-dated coring sites (lakes and wetlands) located across 19 modern-day European countries. We used two independent methods of analysis to evaluate whether the changes we see in the landscape at the time of the Black Death agree with the hypothesis that a large portion of the population, upwards of half, died within a few years in the 21 historical regions we studied. While we can confirm that the Black Death had a devastating impact in some regions, we found that it had negligible or no impact in others. These inter-regional differences in the Black Death's mortality across Europe demonstrate the significance of cultural, ecological, economic, societal and climatic factors that mediated the dissemination and impact of the disease. The complex interplay of these factors, along with the historical ecology of plague, should be a focus of future research on historical pandemics.The authors acknowledge the following funding sources: Max Planck Independent Research Group, Palaeo-Science and History Group (A.I., A.M. and C.V.); Estonian Research Council #PRG323, PUT1173 (A.Pos., T.R., N.S. and S.V.); European Research Council #FP7 263735 (A.Bro. and A.Plu.), #MSC 655659 (A.E.); Georgetown Environmental Initiative (T.N.); Latvian Council of Science #LZP-2020/2-0060 (N.S. and N.J.); LLNL-JRNL-820941 (I.T.); NSF award #GSS-1228126 (S.M.); Polish-Swiss Research Programme #013/2010 CLIMPEAT (M.Lam.), #086/2010 CLIMPOL (A.W.); Polish Ministry of Science and Higher Education #N N306 275635 (M.K.); Polish National Science Centre #2019/03/X/ST10/00849 (M.Lam.), #2015/17/B/ST10/01656 (M.Lam.), #2015/17/B/ST10/03430 (M.Sło.), #2018/31/B/ST10/02498 (M.Sło.), #N N304 319636 (A.W.); SCIEX #12.286 (K.Mar.); Spanish Ministry of Economy and Competitiveness #REDISCO-HAR2017-88035-P (J.A.L.S.); Spanish Ministry of Education, Culture and Sports #FPU16/00676 (R.L.L.); Swedish Research Council #421-2010-1570 (P.L.), #2018-01272 (F.C.L. and A.S.); Volkswagen Foundation Freigeist Fellowship Dantean Anomaly (M.B.), Spanish Ministry of Science and Innovation #RTI2018-101714-B-I00 (F.A.S. and D.A.S.), OP RDE, MEYS project #CZ.02.1.01/0.0/0.0/16_019/0000728 (P.P.
Compensação e incentivo à proteção ambiental: o caso do ICMS ecológico em Minas Gerais
The Fueling and Evolution of AGN: Internal and External Triggers
In this chapter, I review the fueling and evolution of active galactic nuclei
(AGN) under the influence of internal and external triggers, namely intrinsic
properties of host galaxies (morphological or Hubble type, color, presence of
bars and other non-axisymmetric features, etc) and external factors such as
environment and interactions. The most daunting challenge in fueling AGN is
arguably the angular momentum problem as even matter located at a radius of a
few hundred pc must lose more than 99.99 % of its specific angular momentum
before it is fit for consumption by a BH. I review mass accretion rates,
angular momentum requirements, the effectiveness of different fueling
mechanisms, and the growth and mass density of black BHs at different epochs. I
discuss connections between the nuclear and larger-scale properties of AGN,
both locally and at intermediate redshifts, outlining some recent results from
the GEMS and GOODS HST surveys.Comment: Invited Review Chapter to appear in LNP Volume on "AGN Physics on All
Scales", Chapter 6, in press. 40 pages, 12 figures. Typo in Eq 5 correcte
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