Schleiermacher and Otto on religion : a reappraisal

An interpretation of the work of Schleiermacher and Otto recently offered by Andrew Dole, according to which these two thinkers differed over the extent to which religion can be explained naturalistically, and over the sense in which the supernatural can be admitted, is examined and refuted. It is argued that there is no difference between the two thinkers on this issue. It is shown that Schleiermacher's claim that a supernatural event is at the same time a natural event does not invite, but rather forecloses the possibility of, a naturalistic explanation of the event. It is further demonstrated that Otto, like Schleiermacher, denied the existence of supernatural events interpreted as events that infringe the laws of nature

A tight lower bound instance for k-means++ in constant dimension

The k-means++ seeding algorithm is one of the most popular algorithms that is used for finding the initial $k$ centers when using the k-means heuristic. The algorithm is a simple sampling procedure and can be described as follows: Pick the first center randomly from the given points. For $i > 1$, pick a point to be the $i^{th}$ center with probability proportional to the square of the Euclidean distance of this point to the closest previously $(i-1)$ chosen centers. The k-means++ seeding algorithm is not only simple and fast but also gives an $O(\log{k})$ approximation in expectation as shown by Arthur and Vassilvitskii. There are datasets on which this seeding algorithm gives an approximation factor of $\Omega(\log{k})$ in expectation. However, it is not clear from these results if the algorithm achieves good approximation factor with reasonably high probability (say $1/poly(k)$). Brunsch and R\"{o}glin gave a dataset where the k-means++ seeding algorithm achieves an $O(\log{k})$ approximation ratio with probability that is exponentially small in $k$. However, this and all other known lower-bound examples are high dimensional. So, an open problem was to understand the behavior of the algorithm on low dimensional datasets. In this work, we give a simple two dimensional dataset on which the seeding algorithm achieves an $O(\log{k})$ approximation ratio with probability exponentially small in $k$. This solves open problems posed by Mahajan et al. and by Brunsch and R\"{o}glin.Comment: To appear in TAMC 2014. arXiv admin note: text overlap with arXiv:1306.420

Impact of surface-polish on the angular and wavelength dependence of fiber focal ratio degradation

We present measurements of how multimode fiber focal-ratio degradation (FRD) and throughput vary with levels of fiber surface polish from 60 to 0.5 micron grit. Measurements used full-beam and laser injection methods at wavelengths between 0.4 and 0.8 microns on 17 meter lengths of Polymicro FBP 300 and 400 micron core fiber. Full-beam injection probed input focal-ratios between f/3 and f/13.5, while laser injection allowed us to isolate FRD at discrete injection angles up to 17 degrees (f/1.6 marginal ray). We find (1) FRD effects decrease as grit size decreases, with the largest gains in beam quality occurring at grit sizes above 5 microns; (2) total throughput increases as grit size decreases, reaching 90% at 790 nm with the finest polishing levels; (3) total throughput is higher at redder wavelengths for coarser polishing grit, indicating surface-scattering as the primary source of loss. We also quantify the angular dependence of FRD as a function of polishing level. Our results indicate that a commonly adopted micro-bending model for FRD is a poor descriptor of the observed phenomenon.Comment: 10 pages, 7 figures, presented at SPIE Astronomical Telescopes and Instrumentation, July 201

Exploring Vanadium Chemical Transferrin Mimetic Compounds for Insulin Enhancement

Diabetes Mellitus (DM) is caused by a lack of insulin production (Type 1) or the body’s cells’ inability to properly receive it, also known as insulin resistance (Type 2), resulting in greatly elevated levels of blood glucose. Vanadium(IV) and vanadium(V) ions are believed to enhance insulin activity by inhibition of protein tyrosine phosphatase 1B (PTP1B). PTP1B is normally responsible for downregulating the insulin signaling, but in DM type 2, PTP1B activity is overexpressed leading to the insulin signaling blocking. The most promising V(IV) compounds are designed for oral delivery: they are absorbed into the gut and delivered into the bloodstream where they are bound by the iron transporting protein serum transferrin (sTf). STf delivers the compound into cells via endocytosis, where vanadium can bind PTP1B. A limitation of these compounds is their poor stability at the stomach acidic conditions in which they undergo a significant amount of dissociation, resulting in a very inefficient gut absorption. This study explores the use of a chemical transferrin mimetic (cTfm) ligand to create V(IV) and V(V) compounds featuring excellent acidic pH stability for improved gut absorption. The cTfm-V(IV,V) compounds are expected to be labile in the pH of the bloodstream and thus the vanadium species can be quickly ligand exchanged with sTF. The cTfm ligand N,N\u27-di(o-hydroxybenzyl)ethylenediamine-N,N\u27-diacetic acid (HBED) was used to synthesize VO(IV)HBED and VO(V)HBED which demonstrated great aqueous stability in the 1-4 pH range. The role of citrate as a vehicle for delivering vanadium to sTf to regulate the transport of vanadium is also examined

Sensing human hand motions for controlling dexterous robots

The Dexterous Hand Master (DHM) system is designed to control dexterous robot hands such as the UTAH/MIT and Stanford/JPL hands. It is the first commercially available device which makes it possible to accurately and confortably track the complex motion of the human finger joints. The DHM is adaptable to a wide variety of human hand sizes and shapes, throughout their full range of motion

Multi-market minority game: breaking the symmetry of choice

Generalization of the minority game to more than one market is considered. At each time step every agent chooses one of its strategies and acts on the market related to this strategy. If the payoff function allows for strong fluctuation of utility then market occupancies become inhomogeneous with preference given to this market where the fluctuation occured first. There exists a critical size of agent population above which agents on bigger market behave collectively. In this regime there always exists a history of decisions for which all agents on a bigger market react identically.Comment: 15 pages, 12 figures, Accepted to 'Advances in Complex Systems

Plasmonic nanoparticle enhanced photocurrent in GaN/InGaN/GaN quantum well solar cells

We demonstrate enhanced external quantum efficiency and current-voltage characteristics due to scattering by 100 nm silver nanoparticles in a single 2.5 nm thick InGaN quantum well photovoltaic device. Nanoparticle arrays were fabricated on the surface of the device using an anodic alumina template masking process. The Ag nanoparticles increase light scattering, light trapping, and carrier collection in the III-N semiconductor layers leading to enhancement of the external quantum efficiency by up to 54%. Additionally, the short-circuit current in cells with 200 nm p-GaN emitter regions is increased by 6% under AM 1.5 illumination. AFORS-Het simulation software results were used to predict cell performance and optimize emitter layer thickness