38 research outputs found
Upnp-Based Discovery And Management Of Hypervisors And Virtual Machines
The paper introduces a Universal Plug and Play based discovery and management toolkitthat facilitates collaboration between cloud infrastructure providers and users. The presentedtools construct a unified hierarchy of devices and their management-related services, thatrepresents the current deployment of users’ (virtual) infrastructures in the provider’s (physical)infrastructure as well as the management interfaces of respective devices. The hierarchycan be used to enhance the capabilities of the provider’s infrastructure management system.To maintain user independence, the set of management operations exposed by a particulardevice is always defined by the device owner (either the provider or user)
Higgs domain walls in the thermal background
Most cosmological models predict that the universe was hot and dense at the
early stages of it's evolution. In this paper we analyse the influence of the
thermal bath of Standard Model particles on the dynamics of cosmological Higgs
domain walls. This manuscript poses an~extension of our earlier work in which
we investigated the evolution of networks of Higgs domain walls neglecting the
impact of temperature variation.
Using the thermally corrected effective potential of Standard Model we have
found that both the position of the local maximum separating minima
and the width of domain walls strongly depend on temperature . For
temperatures higher than they respectively increase
proportionally and decrease inverse proportionally to the increasing
temperature. Thus, the energy scale of the problem follows the value of
temperature.
Our numerical lattice simulations based on the PRS algorithm reveal that
Higgs domain walls in the presence of the background thermal bath are highly
unstable and decay shortly after formation. Moreover we have found that the
fraction of horizons produced by inflation in which Higgs field expectation
value is higher then needs to be very low in order for the evolution
of the~network of the domain walls to end in the electroweak vacuum. This means
that Higgs domain walls necessarily were very rare objects and their average
energy density was very small. As a result, the domain walls can not
significantly effect cosmological observables
On the dimension of the set of minimal projections
Let be a finite-dimensional normed space and let be its
proper linear subspace. The set of all minimal projections from to is a
convex subset of the space all linear operators from to and we can
consider its affine dimension. We establish several results on the possible
values of this dimension. We prove optimal upper bounds in terms of the
dimensions of and . Moreover, we improve these estimates in the
polyhedral normed spaces for an open and dense subset of subspaces of the given
dimension. As a consequence, in the polyhedral normed spaces a minimal
projection is unique for an open and dense subset of hyperplanes. To prove
this, we establish certain new properties of the Chalmers-Metcalf operator.
Another consequence is the fact, that for every subspace of a polyhedral normed
space, there exists a minimal projection with many norming pairs. Finally, we
provide some more refined results in the hyperplane case.Comment: 31 page
Hydrodynamical constraints on bubble wall velocity
Terminal velocity reached by bubble walls in first order phase transitions is
an important parameter determining both primordial gravitational-wave spectrum
and production of baryon asymmetry in models of electroweak baryogenesis. We
developed a numerical code to study the real-time evolution of expanding
bubbles and investigate how their walls reach stationary states. Our results
agree with profiles obtained within the so-called bag model with very good
accuracy, however, not all such solutions are stable and realised in dynamical
systems. Depending on the exact shape of the potential there is always a range
of wall velocities where no steady state solutions exist. This behaviour in
deflagrations was explained by hydrodynamical obstruction where solutions that
would heat the plasma outside the wall above the critical temperature and cause
local symmetry restoration are forbidden. For even more affected hybrid
solutions causes are less straight forward, however, we provide a simple
numerical fit allowing one to verify if a solution with a given velocity is
allowed simply by computing the ratio of the nucleation temperature to the
critical one for the potential in question
Sources of financing small and medium-sized enterprises : case studies in Poland
Purpose: The article presents selected research results concerning the financing of small and medium-sized enterprises in Poland. The research subject was to gain extensive knowledge of selected sources of financing for SMEs operating in Poland. By learning about the methods of using the funds obtained, as well as identifying the most important features that guide the entrepreneur when choosing the financing sources available on the market. Approach / Methodology / Design: The study used PAPI and CAWI techniques. The survey was conducted at the turn of 2018 and 2019. The research sample included 510 entities. Findings: Entrepreneurs from the SME sector in Poland do not fully use the potential of available financing sources. The authors argue that this state of affairs may be affected by insufficient knowledge about available funding sources. Practical implications: The study showed a need to raise awareness among entrepreneurs about the available financing sources by indicating the role that government institutions should play in this process. Originality/Value: Research attempts to fill a gap in the literature on the subject. These studies can help understand the motives behind selecting specific sources of financing by SMEs operating in Central Europe.peer-reviewe
Stability of domain walls in models with asymmetric potentials
We study the evolution of cosmological domain walls in models with asymmetric
potentials. Our research goes beyond the standard case of spontaneous breaking
of an approximate symmetry. When the symmetry is explicitly broken the
potential exhibits nearly degenerate minima which can lead to creation of a
metastable network of domain walls. The time after which the network will decay
depends on the difference of values of the potential in minima, its asymmetry
around the maximum separating minima and the bias of the initial distribution
of the field. Effect of asymmetry around the maximum separating minima is novel
one that we study with a new type of potential. Using numerical lattice
simulations we determine relative importance of these factors on decay time of
networks for generic potentials. We find that even very small departures from
the symmetric initial distribution case lead to rapid decay of the domain wall
network. As a result creation of a long lasting network capable of producing
observable gravitational wave signals is much more difficult than previously
thought. On the other hand details of the shape of the potential turn out to be
much less important than was expected and the evolution of network from
symmetric distribution is controlled by the difference of values of the
potential in the minima
Perception of food quality labels : an empirical analysis among traditional food producers in Poland
PURPOSE: This paper examines traditional food producers' perceptions of food quality labels,
indicating the incentives and challenges that food producers may face implementing such
schemes. The aim is to identify the main factors affecting traditional food producers' adoption
of food quality labels.DESIGN/METHODOLOGY/APPROACH: The sample was composed of 101 traditional food producers
in Poland that had completed the quality certification process. The survey was based on
computer-assisted telephone interviews with closed questions (5-point Likert scale, ranging
from 1-totally disagree to 5-totally agree). The interviewees were asked to express a judgment
by declaring their level of agreement with the 19 statements. Descriptive statistics and factor
analysis were used for data analysis.FINDINGS: Results show that enterprises adopt quality signs to improve product image,
reputation, and consumer confidence. The protection granted to food labels by the law may
also exert effects on firms' profitability. Producers take advantage of food quality labels in
different ways, according to their size and own business strategies. However, the emphasis
often put on the positive effects of the food quality labels is far from its potentiality in many
cases.PRACTICAL IMPLICATIONS: The study results will be beneficial to both food producers and public
authorities seeking to encourage the application of quality labels in the traditional food sector.
The identified benefits and barriers will help producers to adopt successful business models.
The public authorities should make the certification process more effective and transparent,
and promotion should explain to consumers what the food label guarantees.ORIGINALITY/VALUE: This paper proposes several managerial and policy implications related to
improving the business environment for the adoption of food quality schemes in the traditional
food sector.This research article was supported by the Scientific Research Project
Fund of the University of Warmia and Mazury in Olsztyn.peer-reviewe
The importance of selected cell adhesion molecules in thyroid cancer
Thyroid cancer is the most common malignant tumour of the endocrine system. It accounts for ca. 2% of all malignant tumours in the world, ranking it 16th in the overall classification. Its most common histology type is the papillary carcinoma originating from the epithelial tissue, which embraces approx. 50-80% of all cases.
The epithelial tissue cells in normal conditions are closely interconnected by means of intercellular interactions. The adhesion process is regulated by a series of molecules, called cell adhesion molecules (CAMs). The main representatives of this group, which are increasingly better known and characterised, include the following: E-cadherin, β-catenin, CD44 and CD31 glycoproteins. CAMs regulate the course of many processes, such as differentiation, migration and growth of cells, but they also participate in the transmission of signals to the inside of the cell. Changes in the expression of cell adhesion molecules affect the disruption of the adhesion process. The recent years have seen many scientific reports on the importance of CAMs in the course of neoplastic transformation. It has been proved that abnormalities of CAM expression in many malignant tumours, including the thyroid cancer, are closely related to the increased primary invasion, distant metastasis and worse prognosis. These observations suggest that individual cell adhesion molecules may be used in the future as markers in the diagnostic process of thyroid cancers