3,198 research outputs found
Trends and tendencies in management consulting in light of local and international development
The field of management consulting is now over 100 years old, but there are definite gaps in information about the size and nature of this field at the national, regional, and global levels. The aim of our contribution is to analyze the major trends in management consulting in Hungary and contrast the findings with those reported by FEACO, the European Federation of Management Consulting. The authors were and are actively involved in assmebling data for Hungary, for the EU, and at the global level. We include a brief bird's eye-view on the evolution of this important professional sector.
Infrared behavior of interacting bosons at zero temperature
We review the infrared behavior of interacting bosons at zero temperature.
After a brief discussion of the Bogoliubov approximation and the breakdown of
perturbation theory due to infrared divergences, we present two approaches that
are free of infrared divergences -- Popov's hydrodynamic theory and the
non-perturbative renormalization group -- and allow us to obtain the exact
infrared behavior of the correlation functions. We also point out the
connection between the infrared behavior in the superfluid phase and the
critical behavior at the superfluid--Mott-insulator transition in the
Bose-Hubbard model.Comment: 8 pages, 4 figures. Proceedings of the 19th International Laser
Physics Workshop, LPHYS'10 (Foz do Iguacu, Brazil, July 5-9, 2010
Development of ERAU VOLTRON Hybrid-Electric Powerplant
The energy density of todayâs batteries is not high enough for electric powered aircraft to achieve an operationally viable range plus FAA stipulated reserve flight times. Hybrid-electric power generation systems may be able to bridge the gap, providing a way for these aircraft to fly distances not possible with batteries alone. There is a recognition that gasoline-electric hybrid systems can deliver specific energy and specific power that are higher than any currently available battery system.
Embry-Riddle Aeronautical Universityâs (ERAUâs) Eagle Flight Research Center (EFRC) is building a 70+ kW hybrid-electric power generation system using a rotary engine and Permanent Magnet Synchronous Machine (PMSM) & Inverter. The rotary engine will be directly coupled to the PMSM which will generate electrical energy to power multi-rotor eVTOL vehicles. These results will be achieved by utilizing advanced control systems implemented on a National Instruments Compact RIO.
Past research conducted at the EFRC demonstrated the ability to design and operate a hybrid-electric powerplant. The VOLTRON project will attempt to create a system with an even higher specific energy but with the compact size and high power characteristics of a rotary engine and eventually alternative fuel flexibility
F-theory on Genus-One Fibrations
We argue that M-theory compactified on an arbitrary genus-one fibration, that
is, an elliptic fibration which need not have a section, always has an F-theory
limit when the area of the genus-one fiber approaches zero. Such genus-one
fibrations can be easily constructed as toric hypersurfaces, and various
and models are presented as examples. To each
genus-one fibration one can associate a -function on the base as well as
an representation which together define the IIB axio-dilaton
and 7-brane content of the theory. The set of genus-one fibrations with the
same -function and representation, known as the
Tate-Shafarevich group, supplies an important degree of freedom in the
corresponding F-theory model which has not been studied carefully until now.
Six-dimensional anomaly cancellation as well as Witten's zero-mode count on
wrapped branes both imply corrections to the usual F-theory dictionary for some
of these models. In particular, neutral hypermultiplets which are localized at
codimension-two fibers can arise. (All previous known examples of localized
hypermultiplets were charged under the gauge group of the theory.) Finally, in
the absence of a section some novel monodromies of Kodaira fibers are allowed
which lead to new breaking patterns of non-Abelian gauge groups.Comment: 53 pages, 9 figures, 6 tables. v2: references adde
Anomaly Equations and Intersection Theory
Six-dimensional supergravity theories with N=(1,0) supersymmetry must satisfy
anomaly equations. These equations come from demanding the cancellation of
gravitational, gauge and mixed anomalies. The anomaly equations have
implications for the geometrical data of Calabi-Yau threefolds, since F-theory
compactified on an elliptically fibered Calabi-Yau threefold with a section
generates a consistent six-dimensional N=(1,0) supergravity theory. In this
paper, we show that the anomaly equations can be summarized by three
intersection theory identities. In the process we also identify the geometric
counterpart of the anomaly coefficients---in particular, those of the abelian
gauge groups---that govern the low-energy dynamics of the theory. We discuss
the results in the context of investigating string universality in six
dimensions.Comment: 29 pages + appendices, 8 figures; v2: minor corrections, references
added; v3: minor corrections, reference adde
Predicting language diversity with complex network
Evolution and propagation of the world's languages is a complex phenomenon,
driven, to a large extent, by social interactions. Multilingual society can be
seen as a system of interacting agents, where the interaction leads to a
modification of the language spoken by the individuals. Two people can reach
the state of full linguistic compatibility due to the positive interactions,
like transfer of loanwords. But, on the other hand, if they speak entirely
different languages, they will separate from each other. These simple
observations make the network science the most suitable framework to describe
and analyze dynamics of language change. Although many mechanisms have been
explained, we lack a qualitative description of the scaling behavior for
different sizes of a population. Here we address the issue of the language
diversity in societies of different sizes, and we show that local interactions
are crucial to capture characteristics of the empirical data. We propose a
model of social interactions, extending the idea from, that explains the growth
of the language diversity with the size of a population of country or society.
We argue that high clustering and network disintegration are the most important
characteristics of models properly describing empirical data. Furthermore, we
cancel the contradiction between previous models and the Solomon Islands case.
Our results demonstrate the importance of the topology of the network, and the
rewiring mechanism in the process of language change
Two real parton contributions to non-singlet kernels for exclusive QCD DGLAP evolution
Results for the two real parton differential distributions needed for
implementing a next-to-leading order (NLO) parton shower Monte Carlo are
presented. They are also integrated over the phase space in order to provide
solid numerical control of the MC codes and for the discussion of the
differences between the standard factorization and Monte Carlo
implementation at the level of inclusive NLO evolution kernels. Presented
results cover the class of non-singlet diagrams entering into NLO kernels. The
classic work of Curci-Furmanski-Pertonzio was used as a guide in the
calculations.Comment: 34 pages, 3 figure
On the Hodge structure of elliptically fibered Calabi-Yau threefolds
The Hodge numbers of generic elliptically fibered Calabi-Yau threefolds over
toric base surfaces fill out the "shield" structure previously identified by
Kreuzer and Skarke. The connectivity structure of these spaces and bounds on
the Hodge numbers are illuminated by considerations from F-theory and the
minimal model program. In particular, there is a rigorous bound on the Hodge
number h_{21} <= 491 for any elliptically fibered Calabi-Yau threefold. The
threefolds with the largest known Hodge numbers are associated with a sequence
of blow-ups of toric bases beginning with the Hirzebruch surface F_{12} and
ending with the toric base for the F-theory model with largest known gauge
group.Comment: 16 pages, 4 figures; v2: minor corrections, references added; v3:
minor corrections, improvements, reference added, version for JHE
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