Graded Fock--like representations for a system of algebraically interacting paraparticles

We will present an algebra describing a mixed paraparticle model, known in the bibliography as "The Relative Parabose Set (\textsc{Rpbs})". Focusing in the special case of a single parabosonic and a single parafermionic degree of freedom $P_{BF}^{(1,1)}$, we will study a class of Fock--like representations of this algebra, dependent on a positive integer parameter p (a kind of generalized parastatistics order). Mathematical properties of the Fock--like modules will be investigated for all values of p and constructions such as ladder operators, irreducibility (for the carrier spaces) and Klein group gradings (for both the carrier spaces and the algebra itself) will be established.Comment: 4 pages, 1 ref. updated with respect to the journ. versio

Impending anterior ischemic optic neuropathy with elements of retinal vein occlusion in a patient on interferon for polycythemia vera.

We describe the course and likely pathophysiology of impending anterior ischemic optic neuropathy (AION) and retinal vein occlusion in a 56-year-old man with polycythemia vera managed with interferon alpha for 2 years. Our patient presented with decreased vision, scintillating scotomata, and floaters. Fundus examination findings and results of a fluorescein angiogram led to the diagnosis of impending AION and retinal vein occlusion. Considering that both polycythemia vera and interferon have possible influences on vascular occlusion and optic disc edema, we stopped interferon treatment and immediately attempted to treat the polycythemia vera empirically with pentoxifylline and any interferon-associated inflammation with prednisone. Our patient experienced complete resolution of fundus abnormalities and return of normal vision within 3 weeks, which may be attributed to our successful treatment of both etiologies. Thus, further study is warranted to elucidate the treatment of both polycythemia vera and interferon-induced impending AION

Communication, observability and cooperation: a field experiment on collective water management in India

This study is an empirical investigation of the potential for communication and observability interventions to increase cooperation around communal water treatment systems amongst villagers in rural India. Despite the dependence of many rural communities in India on communal water sources and treatment plants for safe drinking water, they often fail to collectively manage these resources, resulting in abandoned water points and treatment systems with consequent health and mortality impacts. Results of public goods games framed in terms of the management of communal water treatment systems suggest that these communities can cooperate to provide the public good. However, public disclosure of behaviour had the very significant effect of decreasing contributions to the public good. Analysis indicates that early rounds of play were critical in this regard: the observed behaviours of other individuals at the start of play strongly determined subsequent cooperation levels. Thus, frequently-observed free-riding behaviour in early rounds of the game led other players to follow suit. Only when participants were actively encouraged to negotiate agreements, did cooperation increase significantly - albeit intermittently. Overall, findings suggest that interventions that provide opportunities for communication and negotiation may be most effective at enhancing cooperation around communal water treatment plants, while the impacts of interventions that make behaviour observable are strongly dependent on behaviour in the early stages of cooperative interaction

Preferences for water treatment provision in rural India: comparing communal, pay-per-use, and labour-for-water schemes

Using a contingent valuation survey, this research identifies villagers’ willingness to pay towards the operation and maintenance of water treatment plants in 11 villages in Maharashtra with existing facilities. Preferences were elicited using three different payment mechanisms: a monthly fee, labour (time) contributions, and a pay-per-container mechanism. There was little support for the pay-per-container scheme (51% stated positive willingness to pay for this option), but the communal mechanisms were more popular (86.7% and 87.3%). We conclude that the long-term viability of water treatment in Maharashtra is weak, as few scenarios provide adequate revenue to properly operate and maintain the infrastructure

Noninvasive imaging of the thirteen-lined ground squirrel photoreceptor mosaic.

Ground squirrels are an increasingly important model for studying visual processing, retinal circuitry, and cone photoreceptor function. Here, we demonstrate that the photoreceptor mosaic can be longitudinally imaged noninvasively in the 13-lined ground squirrel (Ictidomys tridecemlineatus) using confocal and nonconfocal split-detection adaptive optics scanning ophthalmoscopy using 790 nm light. Photoreceptor density, spacing, and Voronoi analysis are consistent with that of the human cone mosaic. The high imaging success rate and consistent image quality in this study reinforce the ground squirrel as a practical model to aid drug discovery and testing through longitudinal imaging on the cellular scale

Do Guns Displace Books? – The Impact of Compulsory Military Service on Educational Attainment

Compulsory military service typically drafts young men when they are at the height of their learning ability. Thus, it can be expected to depress the demand for higher education since skill atrophy and the delayed entry into the civilian labor market reduce the returns to human-capital investments. Attending university, however, might open the possibility to avoid the draft, leading to an increase in the demand for tertiary education. To estimate the causal eff ect of conscription on the probability to obtain a university degree, we use a regression-discontinuity design that employs special regulations associated with the introduction of conscription in Germany in 1956. We estimate conscription to increase the probability of having a university degree.Regression discontinuity; conscription; career interruption; skill atrophy;TS2SLS

Metric-affine gauge theory of gravity II. Exact solutions

In continuing our series on metric-affine gravity (see Gronwald IJMP D6 (1997) 263 for Part I), we review the exact solutions in this theory.Comment: Revtex file, 25 pages, final version to appear in IJMP

Counting reducible, powerful, and relatively irreducible multivariate polynomials over finite fields

We present counting methods for some special classes of multivariate polynomials over a finite field, namely the reducible ones, the s-powerful ones (divisible by the s-th power of a nonconstant polynomial), and the relatively irreducible ones (irreducible but reducible over an extension field). One approach employs generating functions, another one uses a combinatorial method. They yield exact formulas and approximations with relative errors that essentially decrease exponentially in the input size.Comment: to appear in SIAM Journal on Discrete Mathematic

Fermion Condensate and Vacuum Current Density Induced by Homogeneous and Inhomogeneous Magnetic Fields in (2+1)-Dimensions

We calculate the condensate and the vacuum current density induced by external static magnetic fields in (2+1)-dimensions. At the perturbative level, we consider an exponentially decaying magnetic field along one cartesian coordinate. Non-perturbatively, we obtain the fermion propagator in the presence of a uniform magnetic field by solving the Schwinger-Dyson equation in the rainbow-ladder approximation. In the large flux limit, we observe that both these quantities, either perturbative (inhomogeneous) and non-perturbative (homogeneous), are proportional to the external field, in agreement with early expectations.Comment: 8 pages, 2 figures. Accepted for publication in Phys. Rev.