4,663 research outputs found
Note about a second "evidence" for a WIMP annual modulation
This note, with its five questions, is intended to contribute to a
clarification about a claimed "evidence" by the DAMA group of an annual
modulation of the counting rate of a Dark Matter NaI(Tl) detector as due to a
neutralino (SUSY-LSP) Dark Matter candidate.Comment: LaTex, 3 pages, 2 figure
The Five Star Movement : exception or Vanguard in Europe?
The enduring economic crisis, austerity measures and corruption scandals have created a favourable environment for the advent of new political actors all over Europe. During the last general elections (February 2013), Italy was shocked by the inexorable rise of the Five Star Movement. Beppe Grillo\u2019s creature upset the political system, occupying portions of the public sphere that had been ignored (the web) or gradually abandoned by traditional political parties (the squares). Its unusual campaigning style, its internet-based organisational structure, its atypical political positioning (beyond left and right), and its oversimplification of complex problems all help to explain its electoral performance, and distinguish it from similar anti-establishment parties that have emerged in Europe over the past decade
On Quantum Algorithms
Quantum computers use the quantum interference of different computational
paths to enhance correct outcomes and suppress erroneous outcomes of
computations. In effect, they follow the same logical paradigm as
(multi-particle) interferometers. We show how most known quantum algorithms,
including quantum algorithms for factorising and counting, may be cast in this
manner. Quantum searching is described as inducing a desired relative phase
between two eigenvectors to yield constructive interference on the sought
elements and destructive interference on the remaining terms.Comment: 15 pages, 8 figure
Price v. State: the Price is Not Right—Maryland’s Showcase Showdown with Inconsistent Criminal Jury Verdicts
Efficient discrete-time simulations of continuous-time quantum query algorithms
The continuous-time query model is a variant of the discrete query model in
which queries can be interleaved with known operations (called "driving
operations") continuously in time. Interesting algorithms have been discovered
in this model, such as an algorithm for evaluating nand trees more efficiently
than any classical algorithm. Subsequent work has shown that there also exists
an efficient algorithm for nand trees in the discrete query model; however,
there is no efficient conversion known for continuous-time query algorithms for
arbitrary problems.
We show that any quantum algorithm in the continuous-time query model whose
total query time is T can be simulated by a quantum algorithm in the discrete
query model that makes O[T log(T) / log(log(T))] queries. This is the first
upper bound that is independent of the driving operations (i.e., it holds even
if the norm of the driving Hamiltonian is very large). A corollary is that any
lower bound of T queries for a problem in the discrete-time query model
immediately carries over to a lower bound of \Omega[T log(log(T))/log (T)] in
the continuous-time query model.Comment: 12 pages, 6 fig
Photon Self-Induced Spin to Orbital Conversion in TGG crystal at high laser power
In this paper, we present experimental evidence of a newly discovered
third-order nonlinear optical process Self-Induced Spin-to-Orbital Conversion
(SISTOC) of the photon angular momentum. This effect is the physical mechanism
at the origin of the depolarization of very intense laser beams propagating in
isotropic materials. The SISTOC process, like self-focusing, is triggered by
laser heating leading to a radial temperature gradient in the medium. In this
work we tested the occurrence of SISTOC in a terbium gallium garnet (TGG) rod
for an impinging laser power of about 100~W. To study the SISTOC process we
used different techniques: polarization analysis, interferometry and tomography
of the photon orbital angular momentum. Our results confirm, in particular,
that the apparent depolarization of the beam is due to the occurrence of
maximal entanglement between the spin and orbital angular momentum of the
photons undergoing the SISTOC process. This explanation of the true nature of
the depolarization mechanism could be of some help in finding novel methods to
reduce or to compensate for this usually unwanted depolarization effect in all
cases where very high laser power and good beam quality are required.Comment: 6 pages, 10 figures, submitte
Bifidobacteria and lactobacilli in the gut microbiome of children with non-alcoholic fatty liver disease: which strains act as health players?
Introduction: Non-alcoholic fatty liver disease (NAFLD), considered the leading cause of chronic liver disease in children, can often progress from non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH). It is clear that obesity is one of the main risk factors involved in NAFLD pathogenesis, even if specific mechanisms have yet to be elucidated. We investigated the distribution of intestinal bifidobacteria and lactobacilli in the stools of four groups of children: obese, obese with NAFL, obese with NASH, and healthy, age-matched controls (CTRLs). Material and methods: Sixty-one obese, NAFL and NASH children and 54 CTRLs were enrolled in the study. Anthropometric and metabolic parameters were measured for all subjects. All children with suspected NASH underwent liver biopsy. Bifidobacteria and lactobacilli were analysed in children’s faecal samples, during a broader, 16S rRNA-based pyrosequencing analysis of the gut microbiome. Results: Three Bifidobacterium spp. (Bifidobacterium longum, Bifidobacterium bifidum, and Bifidobacterium adolescentis) and five Lactobacillus spp. (L. zeae, L. vaginalis, L. brevis, L. ruminis, and L. mucosae) frequently recurred in metagenomic analyses. Lactobacillus spp. increased in NAFL, NASH, or obese children compared to CTRLs. Particularly, L. mucosae was significantly higher in obese (p = 0.02426), NAFLD (p = 0.01313) and NASH (p = 0.01079) than in CTRLs. In contrast, Bifidobacterium spp. were more abundant in CTRLs, suggesting a protective and beneficial role of these microorganisms against the aforementioned diseases. Conclusions: Bifidobacteria seem to have a protective role against the development of NAFLD and obesity, highlighting their possible use in developing novel, targeted and effective probiotics
Drosophila Importin-α2 Is Involved in Synapse, Axon and Muscle Development
Nuclear import is required for communication between the cytoplasm and the nucleus and to enact lasting changes in gene transcription following stimuli. Binding to an Importin-α molecule in the cytoplasm is often required to mediate nuclear entry of a signaling protein. As multiple isoforms of Importin-α exist, some may be responsible for the entry of distinct cargoes rather than general nuclear import. Indeed, in neuronal systems, Importin-α isoforms can mediate very specific processes such as axonal tiling and communication of an injury signal. To study nuclear import during development, we examined the expression and function of Importin-α2 in Drosophila melanogaster. We found that Importin-α2 was expressed in the nervous system where it was required for normal active zone density at the NMJ and axonal commissure formation in the central nervous system. Other aspects of synaptic morphology at the NMJ and the localization of other synaptic markers appeared normal in importin-α2 mutants. Importin-α2 also functioned in development of the body wall musculature. Mutants in importin-α2 exhibited errors in muscle patterning and organization that could be alleviated by restoring muscle expression of Importin-α2. Thus, Importin-α2 is needed for some processes in the development of both the nervous system and the larval musculature
Configurations of business model themes and strategies in small firms: a qualitative comparative analysis
Firms' strategies and business model themes (BMTs) entail choices that create a configuration of interdependent elements that ultimately affect a firm's performance. So far, extant studies on BMTs (i.e. novelty, efficiency, complementarity and lock-in) have neglected an explorative analysis of how configurations of BMTs and the choices of a firm's strategy (namely, the source of the competitive advantage and the market scope) are associated with a firm's performance in small and medium enterprises (SMEs). We address this limitation by analysing a sample of 96 small firms using a configurational approach. We identified four equifinal configurations leading to high performance and five equifinal configurations associated with low performance. Overall, our results suggest that in small firms, it is essential to combine a differentiation strategy with either consistent pairs of BMTs or the search for new avenues of value creation and capture, while featuring too many BMTs might be detrimental to their growth. Our study contributes to the scholarly debate about the relationship between business models and strategy
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