584,185 research outputs found
Strongly-interacting fermions from a higher-dimensional unified gauge theory
The method of coset-space dimensional reduction is employed in order to
proceed from a gauged E_8 * E_8' unified theory defined in 10 dimensions to 4
dimensions. The resulting theory comprises the Standard Model along with a
strongly-interacting fermion sector which breaks the electroweak symmetry
dynamically at the right scale.Comment: 12 LaTeX pages, version to be published in Physics Letters
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Individual differences in the neuropsychopathology of addiction.
Drug addiction or substance-use disorder is a chronically relapsing disorder that progresses through binge/intoxication, withdrawal/negative affect and preoccupation/anticipation stages. These stages represent diverse neurobiological mechanisms that are differentially involved in the transition from recreational to compulsive drug use and from positive to negative reinforcement. The progression from recreational to compulsive substance use is associated with downregulation of the brain reward systems and upregulation of the brain stress systems. Individual differences in the neurobiological systems that underlie the processing of reward, incentive salience, habits, stress, pain, and executive function may explain (i) the vulnerability to substance-use disorder; (ii) the diversity of emotional, motivational, and cognitive profiles of individuals with substance-use disorders; and (iii) heterogeneous responses to cognitive and pharmacological treatments. Characterization of the neuropsychological mechanisms that underlie individual differences in addiction-like behaviors is the key to understanding the mechanisms of addiction and development of personalized pharmacotherapy
Set-Based Pre-Processing for Points-To Analysis
We present set-based pre-analysis: a virtually universal op-
timization technique for flow-insensitive points-to analysis.
Points-to analysis computes a static abstraction of how ob-
ject values flow through a program’s variables. Set-based
pre-analysis relies on the observation that much of this rea-
soning can take place at the set level rather than the value
level. Computing constraints at the set level results in sig-
nificant optimization opportunities: we can rewrite the in-
put program into a simplified form with the same essential
points-to properties. This rewrite results in removing both
local variables and instructions, thus simplifying the sub-
sequent value-based points-to computation. E
ectively, set-
based pre-analysis puts the program in a normal form opti-
mized for points-to analysis.
Compared to other techniques for o
-line optimization of
points-to analyses in the literature, the new elements of our
approach are the ability to eliminate statements, and not just
variables, as well as its modularity: set-based pre-analysis
can be performed on the input just once, e.g., allowing the
pre-optimization of libraries that are subsequently reused
many times and for di
erent analyses. In experiments with
Java programs, set-based pre-analysis eliminates 30% of the
program’s local variables and 30% or more of computed
context-sensitive points-to facts, over a wide set of bench-
marks and analyses, resulting in a
20% average speedup
(max: 110%, median: 18%)
Diversifying academic and professional identities in higher education: some management challenges
This paper draws on an international study of the management challenges arising from diversifying academic and professional identities in higher education. These challenges include, for instance, the introduction of practice-based disciplines with different traditions such as health and social care, the changing aspirations and expectations of younger generations of staff, a diffusion of management responsibilities and structures, and imperatives for a more holistic approach to the "employment package", including new forms of recognition and reward. It is suggested that while academic and professional identities have become increasingly dynamic and multi-faceted, change is occurring at different rates in different contexts. A model is offered, therefore, that relates approaches to "people management" to different organisational environments, against the general background of increasing resource constraint arising from the global economic downturn
Gossip in a Smartphone Peer-to-Peer Network
In this paper, we study the fundamental problem of gossip in the mobile
telephone model: a recently introduced variation of the classical telephone
model modified to better describe the local peer-to-peer communication services
implemented in many popular smartphone operating systems. In more detail, the
mobile telephone model differs from the classical telephone model in three
ways: (1) each device can participate in at most one connection per round; (2)
the network topology can undergo a parameterized rate of change; and (3)
devices can advertise a parameterized number of bits about their state to their
neighbors in each round before connection attempts are initiated. We begin by
describing and analyzing new randomized gossip algorithms in this model under
the harsh assumption of a network topology that can change completely in every
round. We prove a significant time complexity gap between the case where nodes
can advertise bits to their neighbors in each round, and the case where
nodes can advertise bit. For the latter assumption, we present two
solutions: the first depends on a shared randomness source, while the second
eliminates this assumption using a pseudorandomness generator we prove to exist
with a novel generalization of a classical result from the study of two-party
communication complexity. We then turn our attention to the easier case where
the topology graph is stable, and describe and analyze a new gossip algorithm
that provides a substantial performance improvement for many parameters. We
conclude by studying a relaxed version of gossip in which it is only necessary
for nodes to each learn a specified fraction of the messages in the system.Comment: Extended Abstract to Appear in the Proceedings of the ACM Conference
on the Principles of Distributed Computing (PODC 2017
Extending the Electron Spin Coherence Time of Atomic Hydrogen by Dynamical Decoupling
We study the electron spin decoherence of encapsulated atomic hydrogen in
octasilsesquioxane cages induced by the 1H and 29Si nuclear spin bath. By
applying the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence we significantly
suppress the low-frequency noise due to nuclear spin flip-flops up to the point
where a maximum T2 = 56 us is observed. Moreover, dynamical decoupling with the
CPMG sequence reveals the existence of two sources of high-frequency noise:
first, a fluctuating magnetic field with the proton Larmor frequency,
equivalent to classical magnetic field noise imposed by the 1H nuclear spins of
the cage organic substituents, and second, decoherence due to entanglement
between the electron and the inner 29Si nuclear spin of the cage
Securing Information-Centric Networking without negating Middleboxes
Information-Centric Networking is a promising networking paradigm that
overcomes many of the limitations of current networking architectures. Various
research efforts investigate solutions for securing ICN. Nevertheless, most of
these solutions relax security requirements in favor of network performance. In
particular, they weaken end-user privacy and the architecture's tolerance to
security breaches in order to support middleboxes that offer services such as
caching and content replication. In this paper, we adapt TLS, a widely used
security standard, to an ICN context. We design solutions that allow session
reuse and migration among multiple stakeholders and we propose an extension
that allows authorized middleboxes to lawfully and transparently intercept
secured communications.Comment: 8th IFIP International Conference on New Technologies, Mobility &
Security, IFIP, 201
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