3,014 research outputs found
Apprentice pay in Britain, Germany and Switzerland: Institutions, market forces and market power
This is the accepted version of the original publication in the European Journal of Industrial Relations, which is available online at http://ejd.sagepub.com/content/19/3/201.The pay of metalworking apprentices is high in Britain, middling in Germany and low in Switzerland. We analyse these differences using fieldwork evidence and survey data, drawing on both economic and institutionalist theories. Several institutional attributes influence apprentice pay, partly by affecting supply and demand in markets for training places. Institutional support for apprenticeship training appears to involve important complementarities in both Germany and Switzerland, in contrast to Britain’s less coherent and more market-driven approach.We thank the Hans-Böckler-Stiftung, Anglo-German Foundation, SKOPE (Oxford), the Swiss federal government (OPET/SERI) and WZB (Berlin) for financial support
Poaching and firm-sponsored training: first clean evidence
A series of seminal theoretical papers argues that poaching of employees may hamper company-sponsored general training. However, the extent of poaching, its determinants and consequences, remains an open empirical question. We provide a novel empirical identification strategy for poaching and investigate its causes and consequences. We find that only a small number of training firms in Germany are poaching victims. Firms are more likely to poach employees during an economic downturn. Training firms respond to poaching by lowering the share of new apprentice intakes in the following years
Fix the Game, Not the Dame: Restoring Equity in Leadership Evaluations
This is the author accepted manuscript. The final version is available from Springer Verlag via the DOI in this record.Female leaders continue to face bias in the workplace compared to male leaders. When employees are evaluated differently because of who they are rather than how they perform, an ethical dilemma arises for leaders and organizations. Thus, bridging role congruity and social identity leadership theories, we propose that gender biases in leadership evaluations can be overcome by manipulating diversity at the team level. Across two multiple-source, multiple-wave, and randomized field experiments, we test whether team gender composition restores gender equity in leadership evaluations. In Study 1, we find that male leaders are rated as more prototypical in male-dominated groups, an advantage that is eliminated in gender-balanced groups. In Study 2, we replicate and extend this finding by showing that leader gender and team gender composition interact to predict trust in the leader via perceptions of leader prototypicality. The results show causal support for the social identity model of organizational leadership and a boundary condition of role congruity theory. Beyond moral arguments of fairness, our findings also show how, in the case of gender, team diversity can create a more level playing field for leaders. Finally, we outline the implications of our results for leaders, organizations, business ethics, and society
Oligomerization and Nitration of the Grass Pollen Allergen Phl p 5 by Ozone, Nitrogen Dioxide, and Peroxynitrite: Reaction Products, Kinetics, and Health Effects
The allergenic and inflammatory potential of proteins can be enhanced by chemical modification upon exposure to atmospheric or physiological oxidants. The molecular mechanisms and kinetics of such modifications, however, have not yet been fully resolved. We investigated the oligomerization and nitration of the grass pollen allergen Phl p 5 by ozone (O(3)), nitrogen dioxide (NO(2)), and peroxynitrite (ONOO(–)). Within several hours of exposure to atmospherically relevant concentration levels of O(3) and NO(2), up to 50% of Phl p 5 were converted into protein oligomers, likely by formation of dityrosine cross-links. Assuming that tyrosine residues are the preferential site of nitration, up to 10% of the 12 tyrosine residues per protein monomer were nitrated. For the reaction with peroxynitrite, the largest oligomer mass fractions (up to 50%) were found for equimolar concentrations of peroxynitrite over tyrosine residues. With excess peroxynitrite, the nitration degrees increased up to 40% whereas the oligomer mass fractions decreased to 20%. Our results suggest that protein oligomerization and nitration are competing processes, which is consistent with a two-step mechanism involving a reactive oxygen intermediate (ROI), as observed for other proteins. The modified proteins can promote pro-inflammatory cellular signaling that may contribute to chronic inflammation and allergies in response to air pollution
FACT -- the First Cherenkov Telescope using a G-APD Camera for TeV Gamma-ray Astronomy (HEAD 2010)
Geiger-mode Avalanche Photodiodes (G-APD) bear the potential to significantly
improve the sensitivity of Imaging Air Cherenkov Telescopes (IACT). We are
currently building the First G-APD Cherenkov Telescope (FACT) by refurbishing
an old IACT with a mirror area of 9.5 square meters and construct a new, fine
pixelized camera using novel G-APDs. The main goal is to evaluate the
performance of a complete system by observing very high energy gamma-rays from
the Crab Nebula. This is an important field test to check the feasibility of
G-APD-based cameras to replace at some time the PMT-based cameras of planned
future IACTs like AGIS and CTA. In this article, we present the basic design of
such a camera as well as some important details to be taken into account.Comment: Poster shown at HEAD 2010, Big Island, Hawaii, March 1-4, 201
Stratified Abstraction of Access Control Policies
The shift to cloud-based APIs has made application security critically depend on understanding and reasoning about policies that regulate access to cloud resources. We present stratified predicate abstraction, a new approach that summarizes complex security policies into a compact set of positive and declarative statements that precisely state who has access to a resource. We have implemented stratified abstraction and deployed it as the engine powering AWS’s IAM Access Analyzer service, and hence, demonstrate how formal methods and SMT can be used for security policy explanation
A novel camera type for very high energy gamma-ray astronomy based on Geiger-mode avalanche photodiodes
Geiger-mode avalanche photodiodes (G-APD) are promising new sensors for light
detection in atmospheric Cherenkov telescopes. In this paper, the design and
commissioning of a 36-pixel G-APD prototype camera is presented. The data
acquisition is based on the Domino Ring Sampling (DRS2) chip. A sub-nanosecond
time resolution has been achieved. Cosmic-ray induced air showers have been
recorded using an imaging mirror setup, in a self-triggered mode. This is the
first time that such measurements have been carried out with a complete G-APD
camera.Comment: 9 pages with 11 figure
Universal Composition with Responsive Environments
In universal composability frameworks, adversaries (or environments) and protocols/ideal functionalities often have to exchange meta-information on the network interface, such as algorithms, keys, signatures, ciphertexts, signaling information, and corruption-related messages. For these purely modeling-related messages, which do not reflect actual network communication, it would often be very reasonable and natural for adversaries/environments to provide the requested information immediately or give control back to the protocol/functionality immediately after having received some information. However, in none of the existing models for universal composability is this guaranteed. We call this the \emph{non-responsiveness problem}. As we will discuss in the paper, while formally non-responsiveness does not invalidate any of the universal composability models, it has many disadvantages, such as unnecessarily complex specifications and less expressivity. Also, this problem has often been ignored in the literature, leading to ill-defined and flawed specifications. Protocol designers really should not have to care about this problem at all, but currently they have to: giving the adversary/environment the option to not respond immediately to modeling-related requests does not translate to any real attack scenario.
This paper solves the non-responsiveness problem and its negative consequences completely, by avoiding this artificial modeling problem altogether. We propose the new concepts of responsive environments and adversaries. Such environments and adversaries must provide a valid response to modeling-related requests before any other protocol/functionality is activated. Hence, protocol designers do no longer have to worry about artifacts resulting from such requests not being answered promptly. Our concepts apply to all existing models for universal composability, as exemplified for the UC, GNUC, and IITM models, with full definitions and proofs (simulation relations, transitivity, equivalence of various simulation notions, and composition theorems) provided for the IITM model
Composable and Finite Computational Security of Quantum Message Transmission
Recent research in quantum cryptography has led to the development of schemes
that encrypt and authenticate quantum messages with computational security. The
security definitions used so far in the literature are asymptotic, game-based,
and not known to be composable. We show how to define finite, composable,
computational security for secure quantum message transmission. The new
definitions do not involve any games or oracles, they are directly operational:
a scheme is secure if it transforms an insecure channel and a shared key into
an ideal secure channel from Alice to Bob, i.e., one which only allows Eve to
block messages and learn their size, but not change them or read them. By
modifying the ideal channel to provide Eve with more or less capabilities, one
gets an array of different security notions. By design these transformations
are composable, resulting in composable security.
Crucially, the new definitions are finite. Security does not rely on the
asymptotic hardness of a computational problem. Instead, one proves a finite
reduction: if an adversary can distinguish the constructed (real) channel from
the ideal one (for some fixed security parameters), then she can solve a finite
instance of some computational problem. Such a finite statement is needed to
make security claims about concrete implementations.
We then prove that (slightly modified versions of) protocols proposed in the
literature satisfy these composable definitions. And finally, we study the
relations between some game-based definitions and our composable ones. In
particular, we look at notions of quantum authenticated encryption and QCCA2,
and show that they suffer from the same issues as their classical counterparts:
they exclude certain protocols which are arguably secure.Comment: 43+11 pages, 18 figures, v2: minor changes, extended version of the
published pape
FACT -- The G-APD revolution in Cherenkov astronomy
Since two years, the FACT telescope is operating on the Canary Island of La
Palma. Apart from its purpose to serve as a monitoring facility for the
brightest TeV blazars, it was built as a major step to establish solid state
photon counters as detectors in Cherenkov astronomy. The camera of the First
G-APD Cherenkov Telesope comprises 1440 Geiger-mode avalanche photo diodes
(G-APD), equipped with solid light guides to increase the effective light
collection area of each sensor. Since no sense-line is available, a special
challenge is to keep the applied voltage stable although the current drawn by
the G-APD depends on the flux of night-sky background photons significantly
varying with ambient light conditions. Methods have been developed to keep the
temperature and voltage dependent response of the G-APDs stable during
operation. As a cross-check, dark count spectra with high statistics have been
taken under different environmental conditions. In this presentation, the
project, the developed methods and the experience from two years of operation
of the first G-APD based camera in Cherenkov astronomy under changing
environmental conditions will be presented.Comment: Proceedings of the Nuclear Science Symposium and Medical Imaging
Conference (IEEE-NSS/MIC), 201
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