Spectral Ray Differentials

Light refracted by a dispersive interface leads to beautifully colored patterns that can be rendered faithfully with spectral Monte‐Carlo methods. Regrettably, results often suffer from chromatic noise or banding, requiring high sampling rates and large amounts of memory compared to renderers operating in some trichromatic color space. Addressing this issue, we introduce spectral ray differentials, which describe the change of light direction with respect to changes in the spectrum. In analogy with the classic ray and photon differentials, this information can be used for filtering in the spectral domain. Effectiveness of our approach is demonstrated by filtering for offline spectral light and path tracing as well as for an interactive GPU photon mapper based on splatting. Our results show considerably less chromatic noise and spatial aliasing while retaining good visual similarity to reference solutions with negligible overhead in the order of milliseconds.     

Scanning electron microscope (SEM) disclosure of the effects of snake venom on living tissue integrity and cell surfaces

The tissue destruction produced by the bite of the viper is well known and the venom enzyme[s] that produce it have been thoroughly studied. Not so well examined is the view of the damage available to the electron microscope, especially the scanning electron microscope. Here we have used the SEM to view the effects of viper venom on living tissue in situ. SCANNING 32: 155–158, 2010. © 2010 Wiley Periodicals, Inc.     

Estimating the entropy rate of spike trains via Lempel-Ziv complexity

Normalized Lempel-Ziv complexity, which measures the generation rate of new patterns along a digital sequence, is closely related to such important source properties as entropy and compression ratio, but, in contrast to these, it is a property of individual sequences. In this article, we propose to exploit this concept to estimate (or, at least, to bound from below) the entropy of neural discharges (spike trains). The main advantages of this method include fast convergence of the estimator (as supported by numerical simulation) and the fact that there is no need to know the probability law of the process generating the signal. Furthermore, we present numerical and experimental comparisons of the new method against the standard method based on word frequencies, providing evidence that this new approach is an alternative entropy estimator for binned spike trains.     

Adaptive statistical algorithms in network reliability analysis

The paper is concerned with introducing novel algorithms, such as adaptive approximation and deterministic radial basis function (RBF) method, for calculating the average loss (AL). Different approximators are trained to approximate the loss function and, after a short learning period, AL can be evaluated analytically with fast calculations. An improvement of the Li–Silvester (LS) method is also presented which yields a sharper lower bound on AL. The efficiency of the new methods are proven by theoretical analysis as well as demonstrated by excessive simulations.     

Chronic Oral Selegiline Treatment Mitigates Age-Related Hearing Loss in BALB/c Mice

Age-related hearing loss (ARHL), a sensorineural hearing loss of multifactorial origin, increases its prevalence in aging societies. Besides hearing aids and cochlear implants, there is no FDA approved efficient pharmacotherapy to either cure or prevent ARHL. We hypothesized that selegiline, an antiparkinsonian drug, could be a promising candidate for the treatment due to its complex neuroprotective, antioxidant, antiapoptotic, and dopaminergic neurotransmission enhancing effects. We monitored by repeated Auditory Brainstem Response (ABR) measurements the effect of chronic per os selegiline administration on the hearing function in BALB/c and DBA/2J mice, which strains exhibit moderate and rapid progressive high frequency hearing loss, respectively. The treatments were started at 1 month of age and lasted until almost a year and 5 months of age, respectively. In BALB/c mice, 4 mg/kg selegiline significantly mitigated the progression of ARHL at higher frequencies. Used in a wide dose range (0.15–45 mg/kg), selegiline had no effect in DBA/2J mice. Our results suggest that selegiline can partially preserve the hearing in certain forms of ARHL by alleviating its development. It might also be otoprotective in other mammals or humans.     

Tail behaviour and extremes of two-state Markov-switching autoregressive models

We examine the tail behaviour and extremal cluster characteristics of two-state Markov-switching autoregressive models where the first regime behaves like a random walk, the second regime is a stationary autoregression, and the generating noise is light-tailed. Under additional technical conditions we prove that the stationary solution has asymptotically exponential tail and the extremal index is smaller than one. The extremal index and the limiting cluster size distribution of the process are calculated explicitly for some noise distributions, and simulated for others. The practical relevance of the results is illustrated by examining extremal properties of a regime-switching autoregressive process with Gamma-distributed noise, already applied successfully in river flow modeling. The limiting aggregate excess distribution is shown to possess Weibull-like tail in this special case.     

Photonic slot routing: a cost effective approach to designingall-optical access and metro networks

In the backbone network, the high level of traffic aggregation achieved by numerous users is efficiently served by means of optical circuit switched solutions-the so-called wavelength routing approach. In the access and metro networks, on the contrary, the reduced level of traffic aggregation makes wavelength routing solutions inadequate. The finer and more dynamic bandwidth allocation provided by packet-interleaved optical time-division multiplexing is thus advocated in these network areas. This article presents a survey of an OTDM approach, known as photonic slot routing, or PSR. It is illustrated how this approach may provide a cost-effective solution to deploying all-optical access and metro networks with today's technology     

Long-term results of minimally invasive lumbar disc surgery

Long-term results of minimally invasive primary lumbar discectomies are processed. The operation was fairly simple and inexpensive, with reduced hospital stay (24 hours). The subsequent rehabilitation was compared to the more extensive procedures. The Oswestry-style questionnaires were found to be gratifying with a high percentage (80.9%) of patients, who returned to normal or nearly normal lives. No significant difference was found with published results of microdiscectomy.     

Towards a genealogy of urban shopping: types,adaptations and resilience

This typological account of the urban morphology of shopping presents a diagrammatic genealogy of urban retail types from traditional markets, streets and plazas through various adaptations and mutations into the contemporary shopping mall and power centre. This genealogy shows an increased car-dependency, privatized and centralized control, and disintegration from urban life. Many cities have been transformed by contemporary retail types that are less walkable, equitable, productive and resilient than those from which they were derived. The challenge lies in the invention of new retail types with potential for re-integration into more resilient forms of urban development.     

Coupled-line metamaterial coupler having co-directional phase but contra-directional power flow

A coupled-line coupler comprising a microstrip line, edge-coupled to a negative-refractive-index line, exhibits co-directional phase but contra-directional Poynting vectors on the lines, leading to backward coupling. A key feature of this coupler is that it can support complex coupled modes. The resulting exponential field decay enables enhanced coupling with moderate line lengths and spacing. An example 3 dB device has been implemented and tested at 3 GHz.