No difference in variability of unique hue selections and binary hue selections

If unique hues have special status in phenomenological experience as perceptually pure, it seems reasonable to assume that they are represented more precisely by the visual system than are other colors. Following the method of Malkoc et al. (J. Opt. Soc. Am. A22, 2154 [2005]), we gathered unique and binary hue selections from 50 subjects. For these subjects we repeated the measurements in two separate sessions, allowing us to measure test-retest reliabilities (0.52≤ρ≤0.78; p≪0.01). We quantified the within-individual variability for selections of each hue. Adjusting for the differences in variability intrinsic to different regions of chromaticity space, we compared the within-individual variability for unique hues to that for binary hues. Surprisingly, we found that selections of unique hues did not show consistently lower variability than selections of binary hues. We repeated hue measurements in a single session for an independent sample of 58 subjects, using a different relative scaling of the cardinal axes of MacLeod-Boynton chromaticity space. Again, we found no consistent difference in adjusted within-individual variability for selections of unique and binary hues. Our finding does not depend on the particular scaling chosen for the Y axis of MacLeod-Boynton chromaticity space

Synchronised laser chaos communication: statistical investigation of an experimental system

The paper is concerned with analyzing data from an experimental antipodal laser-based chaos shift-keying communication system. Binary messages are embedded in a chaotically behaving laser wave which is transmitted through a fiber-optic cable and are decoded at the receiver using a second laser synchronized with the emitter laser. Instrumentation in the experimental system makes it particularly interesting to be able to empirically analyze both optical noise and synchronization error as well as bit error rate. Both the noise and error are found to significantly depart in distribution from independent Gaussian. The conclusion from bit error rate results is that the antipodal laser chaos shift-keying system can offer a feasible approach to optical communication. The non-Gaussian optical noise and synchronous error results are a challenge to current theoretical modelling

Binary time series generated by chaotic logistic maps

This paper examines stochastic pairwise dependence structures in binary time series obtained from discretised versions of standard chaotic logistic maps. It is motivated by applications in communications modelling which make use of so-called chaotic binary sequences. The strength of non-linear stochastic dependence of the binary sequences is explored. In contrast to the original chaotic sequence, the binary version is non-chaotic with non-Markovian non-linear dependence, except in a special case. Marginal and joint probability distributions, and autocorrelation functions are elicited. Multivariate binary and more discretised time series from a single realisation of the logistic map are developed from the binary paradigm. Proposals for extension of the methodology to other cases of the general logistic map are developed. Finally, a brief illustration of the place of chaos-based binary processes in chaos communications is given.Binary sequence; chaos; chaos communications; dependence; discretisation; invariant distribution; logistic map; randomness

A new autoregressive time series model in exponential variables (NEAR(1))

A new time series model for exponential variables having first order autoregressive structure is presented. Unlike the recently studied standard autoregressive model in exponential variables (EAR(1)), runs of constantly scaled values are avoidable, and the two parameter structure allows some adjustment of time nonreversibility effects in sample path behavior. The model is further developed by the use of cross-coupling and antithetic ideas to allow negative dependency. Joint distributions and autocorrelations are investigated. A transformed version of the model has a uniform marginal distribution and its correlation and regression structures are also obtained. Estimation aspects of the models are briefly considered. (Author)Naval Postgraduate School, Monterey, CAhttp://archive.org/details/newautoregressiv00lawrN0001480WR0005

A moving average exponential point process (EMA1)

A construction is given for a stationary sequence of random variables the set (X sub i) which have exponential marginal distributions and are random linear combinations of order one of an i.i.d. exponential sequence the set (epsilon sub i). The joint and trivariate exponential distributions of (X sub (i-1), (X sub i) and (X sub (i + 1)) are studied, as well as the intensity function, point spectrum and variance time curve for the point process which has the set (X sub i) sequence for successive times between events. Initial conditions to make the point process count stationary are given, and extensions to higher order moving averages and Gamma point processes are discussedsupported in part by the Office of Naval Research, the National Science Foundation and the United Kingdom Science Research Councilhttp://archive.org/details/movingaverageexp00lawrN

Holographic Technidilaton and LHC searches

We analyze in detail the phenomenology of a model of dynamical electroweak symmetry breaking inspired by walking technicolor, by using the techniques of the bottom-up approach to holography. The model admits a light composite scalar state, the dilaton, in the spectrum. We focus on regions of parameter space for which the mass of such dilaton is 125 GeV, and for which the bounds on the precision electroweak parameter S are satisfied. This requires that the next-to-lightest composite state is the techni-rho meson, with a mass larger than 2.3 TeV. We compute the couplings controlling the decay rates of the dilaton to two photons and to two (real or virtual) Z and W bosons. For generic choices of the parameters, we find a suppression of the decay into heavy gauge bosons, in respect to the analog decay of the standard-model Higgs. We find a dramatic effect on the decay into photons, which can be both strongly suppressed or strongly enhanced, the latter case corresponding to the large-N regime of the dual theory. There is a correlation between this decay rate of the dilaton into photons and the mass splitting between the techni-rho meson and its axial-vector partner: if the decay is enhanced in respect to the standard-model case, then the heavy spin-1 resonances are nearly degenerate in mass, otherwise their separation in mass is comparable to the mass scale itself.Comment: Very minor typos corrected. References adde

Chromosomal ampC mutations in cefpodoxime-resistant ESBL-negative uropathogenic escherichia coli

AmpC beta-lactamase is an enzyme commonly produced by Escherichia coli that causes resistance to cephalosporins and penicillins. Enzyme production is controlled by the strength of the promoter encoded by the chromosomal ampC gene, with the level of production affected by the presence of certain mutations in this region. This study sets out to determine the prevalence of ampC promoter mutations present in a group of uropathogenic E. coli strains. A total of 50 clinical strains of E. coli were collected from urine samples between June 2011 and November 2011. Strains were investigated for the presence of mutations in the chromosomal ampC promoter region by amplification and sequencing of a 271 bp product. The presence of ampC-carrying plasmids derived from other species was also determined, to exclude these from further analysis. ampC-carrying plasmids were found in 10 of the 50 strains, all of which were of the CIT-type. Analysis of the chromosomal ampC promoter region in the 40 remaining strains showed mutations at 16 different positions, with 18 different genotype patterns detected overall. The most common ampC chromosomal mutation, present in 25 of 40 strains, was a T→A transition at position -32. This mutation has been shown by others to increase enzyme production by up to 46-fold. Altogether, three separate mutations (-32, -42 and -13ins) were present in 90% of the 40 non-plasmid strains, indicating a strong association with the resistance observed. It appears, therefore, that the majority of AmpC-mediated resistance in E. coli can be accounted for by just three point mutations in the chromosome

Planning for the perfect storm: perceptions of UK mental health professionals on the increasing impacts of climate change on their service users

Introduction Climate change poses a considerable risk of further increasing the world's mental health burden. The ways that, and extent to which, climate change is affecting mental health service users is poorly known. Mental health professionals (MHP)s' views on the nature of climate-related distress and the need for specialist training to support service users is undetermined globally. Methods A questionnaire survey was disseminated to an opportunity sample of MHPs based in the United Kingdom (UK). It investigated whether MHPs perceived that the number of service users mentioning climate change as affecting their mental health or emotional distress had increased in the five years prior to 2021, and if they believe it will increase further. The survey explored MHPs’ perceptions of the influence of climate change on service users’ mental health needs, if they perceive this to be rational, and if they feel adequately prepared to manage climate change related mental health problems or emotional distress. Results We surveyed 75 MHPs, including professionals in psychotherapy (38), psychology (19), psychiatry (6). MHPs reported a significant increase in the perceived prevalence of mental health problems or emotional distress related to climate change, believing this increase will continue. MHPs reported a range of impacts on service users due to climate change, typically viewed as a rational response. MHPs felt equipped to manage the consequences of climate change but would benefit from specific training. Conclusions Our results indicate an increasing incidence of climate-related emotional distress among service users as perceived by MHPs. The expectation among professionals is that this service need is here now but will continue to increase in the future, with potential implications for the provision of training