1,872 research outputs found
Economics of Scope, Agglomeration and Location of the Multinational Firm
A classification of the locational patterns of firms (with economies of scope present) is outlined, in order to cast light on the location of the multiplant, multinational firm. This is driven by three forces: economies of scope that follow from the co-location of different activities; transportation costs of the final good; and factor mobility costs. It is concluded that the single-plant firm prevails when spatial economies of scope are strong in relation to either transportation or mobility costs. The vertical (horizontal) multiplant firm emerges when mobility costs of factors (transportation costs on the final good) are high. These two kinds of spatial costs, which are mutually exclusive, favor the formation of multinational firms.Economies of scope; Economies of agglomeration; Multiplant firms; Multinational firms.
Barrierless procedure for substitutionally doping graphene sheets with boron atoms: ab initio calculations
Using ab initio methods, we propose a simple and effective way to
substitutionally dope graphene sheets with Boron. The method consists of
selectively exposing each side of the graphene sheet to different elements. We
first expose one side of the membrane to Boron, while the other side is exposed
to Nitrogen. Proceeding this way, the B atoms will be spontaneously
incorporated into the graphene membrane, without any activation barrier. In a
second step, the system should be exposed to a H-rich environment, that will
remove the CN radical from the layer and form HCN, leading to a perfect
substitutional doping.Comment: Accepted Physical Review
Information flow and declassification analysis for legacy and untrusted programs
Standard access control mechanisms are often insufficient to enforce compliance of programs with security policies. For this reason, information flow analysis has become a topic of increasing interest. In such type of analysis, the main property to be checked is called non-interference, which basically states that the publicly observable behaviour of a program is entirely independent of its secret, secure input values. However, simple non-interference is too restrictive for specifying and enforcing in- formation flow policies in most programs. Exceptions to non-interference are provided using declassification policies. Several approaches for enforcing declassification have been proposed in the literature. In most of these approaches, the declassification policies are embedded in the program itself or heavily tied to the variables in the program being analyzed, thereby providing at best little separation between the code and the policy. Consequently, the previous approaches essentially require that the code be trusted, since to trust that the correct policy is being enforced, we need to trust the source code. In this thesis, we propose a novel framework for information flow analysis, with support to declassification policies, related to the source code being analyzed via its I/O channels. The framework supports many of the of declassification policies identified in the literature. Based on flow-based static analysis, it represents a first step towards a new approach that can be applied to untrusted and legacy source code to automatically verify that the analyzed program complies with the specified declassification policies. We present a framework in which expressions over input channel values that could be output by the program are compared to a set of declassification requirements. We build an implementation of such framework, which works by constructing a conservative approximation of the such expressions, and by determining whether all of them satisfy the declassification requirements stated in the policy. We introduce a representation of such expressions that resembles tree automata. We prove that if a program is considered safe according to our analysis then it satisfies a property we call Policy Controlled Release, which formalizes information-flow correctness according to our notion of declassification policy. We demonstrate, through examples, that our approach works for several interesting and useful declassification policies, including one involving declassification of the average of several confidential values. Finally, we extend the static analyzer to build a practical hybrid static-runtime enforcement mechanism, consisting of 3 steps: static analysis, preload checking, and runtime enforcement. We demonstrate how the hybrid mechanism is able to enforce real-world policies which are unable to be treated by standard approaches from industry. Also, we show how this goal is achieved by keeping the static analysis step system independent, and the runtime enforcement with minimum runtime overhead
Formation of Atomic Carbon Chains from Graphene Nanoribbons
The formation of one-dimensional carbon chains from graphene nanoribbons is
investigated using it ab initio molecular dynamics. We show under what
conditions it is possible to obtain a linear atomic chain via pulling of the
graphene nanoribbons. The presence of dimers composed of two-coordinated carbon
atoms at the edge of the ribbons is necessary for the formation of the linear
chains, otherwise there is simply the full rupture of the structure. The
presence of Stone-Wales defects close to these dimers may lead to the formation
of longer chains. The local atomic configuration of the suspended atoms
indicates the formation of single and triple bonds, which is a characteristic
of polyynes.Comment: 4 pages, 5 figure
Economies of Scope, Agglomeration and Location of the Multinational Firm
A classification of the locational patterns of firms (with economies of scope present) is outlined, in order to cast light on the location of the multiplant, multinational firm. This is driven by three forces: economies of scope that follow from the co-location of different activities; transportation costs of the final good; and factor mobility costs. It is concluded that the single-plant firm prevails when spatial economies of scope are strong in relation to either transportation or mobility costs. The vertical (horizontal) multiplant firm emerges when mobility costs of factors (transportation costs on the final good) are high. These two kinds of spatial costs, which are mutually exclusive, favor the formation of multinational firms
Location of vertically linked oligopolists
This paper examines the geographical equilibrium of location of N vertically linked firms and its relation to the creation of an industrial cluster. In a two-region spatial economy, a monopolist firm supplies an input to N consumer goods firms that compete in quantities. When the transport cost of the input increases, downstream firms prefer to agglomerate where the upstream firm is located, to save in production cost. However, simultaneous increases in the transport cost of the input and of the consumer good or increases in the number of downstream firms lead to a relative dispersion of these firms, to reduce competition and locate closer to the local final consumer. In contrast to Mayer (2000), when both transport costs increase, the location decision of downstream firms is based more on the geographical point that maximizes accessibility to the local final consumer than on the geographical point that minimizes the production cost.info:eu-repo/semantics/publishedVersio
Effects of social media brand-related content on fashion products buying behaviour – a moderated mediation model
Purpose – This study examines in which circumstances consumer’s self-congruity moderates the indirect influence of consumer-based brand equity (mediating role) in the relationship between firm-created and user-generated social media content and intention to purchase fashion products.
Design/methodology/approach – In this study, we carried out an online survey with social media users of fashion brands and collected data from 622 participants across two samples to investigate whether consumers’ perceptions of equity of fashion brands mediate the relationship between social media brand-related communication created by both firms and users and the intention to buy the fashion brands. The indirect relationship is further moderated by self-congruity.
Findings – The results indicate that (i) brand equity mediates the relationship between social media communication and purchase intentions of fashion products, and (ii)
self-congruity moderates the relationship between social media communication types and purchase intentions, such that higher/lower levels of self-congruity strengthen/weaken the impact of social media communication on purchase intentions.
Originality/value – This study contributes to the business and marketing literature by exploring how social media communication, branding, and fashion align with the
individual’s self-concept and buying behaviour
Procedimento de operação, manutenção e verificação de centrÃfuga JOUAN refrigerada.
bitstream/CENARGEN/29585/1/ct064.pd
North American entomophagy
Eating insects is not a common Northern American practice today. However, in the past a variety of insect species was consumed in Northern America (north of Mexico including Greenland). The aim of this literature review is to provide an historical overview of North American entomophagy based upon both peer and non-peer reviewed sources on this topic. Regional differences in insect consumption and reasons for being underreported are discussed. We show that North American natives, and in certain cases colonists, collected and consumed a large variety of edible insects. These are categorized per order and where available, information on how these species were collected and processed is provided. Lastly, we mention reasons for the renewed interest in edible insects in North America, and make suggestions for future studies
- …