Flicker sensitivity as a function of spectral density of external white temporal noise

Foveal flicker sensitivity at 0.5-30 Hz was measured as a function of the spectral density of external, white, purely temporal noise for a sharp-edged 2.5 deg circular spot (mean luminance 3.4 log phot td). Sensitivity at any given temporal frequency was constant at low powers of external noise, but then decreased in inverse proportion to the square root of noise spectral density. Without external noise, sensitivity as function of temporal frequency had the well-known band-pass characteristics peaking at about 10 Hz, as previously documented in a large number of studies. In the presence of strong external noise, however, sensitivity was a monotonically decreasing function of temporal frequency. Our data are well described (goodness of fit 90%) by a model comprising (i) low-pass filtering by retinal cones, (ii) high-pass filtering in the subsequent neural pathways, (iii) adding of the temporal equivalent of internal white spatiotemporal noise, and (iv) detection by a temporal matched filter, the efficiency of which decreases approximately as the power -0.58 of temporal frequency.     

The Rules of Beeping: Exchanging Messages Via Intentional "Missed Calls" on Mobile Phones

This article explores the practice of "beeping" or "missed calling" between mobile phone users, or calling a number and hanging up before the mobile's owner can pick up the call. Most beeps are requests to call back immediately, but they can also send a pre-negotiated instrumental message such as "pick me up now" or a relational sign, such as "I'm thinking of you." The practice itself is old, with roots in landline behaviors, but it has grown tremendously, particularly in the developing world. Based on interviews with small business owners and university students in Rwanda, the article identifies three kinds of beeps (callback, pre-negotiated instrumental, and relational) and the norms governing their use. It then assesses the significance of the practice using adaptive structuration theory. In concluding, the article contrasts beeping with SMS/text messaging, discusses its implications for increasing access to telecommunications services, and suggests paths for future research.     

Pyrolysed carbon supported cobalt porphyrin: a potent catalyst for oxidation of hydrogen sulfide

Pyrolysed carbon supported cobalt porphyrin, an electrocatalyst that is frequently used for oxygen reduction in fuel cells, is evaluated for catalytic oxidation of hydrogen sulfide by dissolved dioxygen. The catalyst performs best after heat treatment at 880 °C_, at pH 8. Analysis of the reaction products reveals that sulfur is the dominant product throughout the investigated pH range 5–10. The catalyst performs much better than powdered activated carbon, granular activated carbon and different other forms of unmodified carbon catalysts. This is as far as we know the first time that heat treated cobalt porphyrins are evaluated for non-electrocatalytic applications.     

Jennifer Government

One of the special pleasures of the Harry Potter stories is their send-up of modern consumer culture--from Bertie Botts' Every Flavour Beans (and they do mean every flavor) to Chocolate Frogs, which come complete with a collectible card featuring a celebrity witch or wizard. Potter's creator, J.K. Rowling, pokes fun at contemporary marketing and advertising with tongue-in-cheek warmth that manages to make her simultaneously attractive to Madison Avenue and the rest of us--a remarkable achievement. Max Barry's Jennifer Government, the satirical successor to his well-received first novel Syrup, takes a different angle on the consumer-marketing-gone-mad theme.     

Assessing the aggregation behaviour of iron oxide nanoparticles under relevant environmental conditions using a multi-method approach

Iron nanoparticles are becoming increasingly popular for the treatment of contaminated soil and groundwater; however, their mobility and reactivity in subsurface environments are significantly affected by their tendency to aggregate. Assessing their stability under environmental conditions is crucial for determining their environmental fate. A multi-method approach (including different size-measurement techniques and the DLVO theory) was used to thoroughly characterise the behaviour of iron oxide nanoparticles (Fe₂O₃NPs) under environmentally relevant conditions. Although recent studies have demonstrated the importance of using a multi-method approach when characterising nanoparticles, the majority of current studies continue to use a single-method approach.Under some soil conditions (i.e. pH 7, 10 mM NaCl and 2 mM CaCl₂) and increasing particle concentration, Fe₂O₃NPs underwent extensive aggregation to form large aggregates (>1 μm). Coating the nanoparticles with dissolved organic matter (DOM) was investigated as an alternative “green” solution to overcoming the aggregation issue instead of using the more commonly proposed polyelectrolytes. At high concentrations, DOM effectively covered the surface of the Fe₂O₃NPs, thereby conferring negative surface charge on the particles across a wide range of pH values. This provided electrostatic stabilisation and considerably reduced the particle aggregation effect. DOM-coated Fe₂O₃NPs also proved to be more stable under high ionic strength conditions. The presence of CaCl₂, however, even at low concentrations, induced the aggregation of DOM-coated Fe₂O₃NPs, mainly via charge neutralisation and bridging. This has significant implications in regards to the reactivity and fate of these materials in the environment.     

The physicochemical properties and in vitro digestibility of selected cereals,tubers and legumes grown in China

Digestibility, gelatinization, retrogradation and pasting properties of starch in various cereal, tuber and legume flours were determined. Rapidly and slowly digestible starch and resistant starch were present in 11 selected flours. In general, cereal starches were more digestible than legume starches and tuber starches contained a high amount of resistant starch. Thermal and rheological properties of flours were different depending on the crop source.     

Impact of γ-irradiation,CIPC treatment,and storage conditions on physicochemical and nutritional properties of potato starches

In the present study, three potato varieties were treated with chlorpropham (CIPC, 35 ppm), γ-irradiated (0.1 kGy) and stored for up to 5 months at 8 °C, and the physicochemical properties and in vitro starch digestibility of native and cooked starches were investigated. Sprouting was found to be satisfactorily suppressed by γ-irradiation and CIPC treatment. However, irradiation increased total free glucose content in two potato varieties, and decreased the thermal transition and pasting temperature of starch. The crystallinity of starch in irradiated potatoes decreased significantly (p ? 0.05) which may explain its decreased resistant starch content. Sprout inhibiting treatments and storage had no effect on in vitro starch digestibility in cooked starches, but cooling cooked starch significantly (p ? 0.05) increased its resistant starch content.     

呼吸房子——现代沙特房屋

项目地点:沙特阿拉伯利雅得项目类型:建筑(住宅)开工日期:未知该项目获2005年豪瑞可持续建筑大奖赛非洲中东地区提名奖     

Wave-front reconstruction with a shack-hartmann sensor with an iterative spline fitting method

One limitation of the conventional Shack-Hartmann sensor is that the spots of each microlens have to remain in their respective subapertures. We present an algorithm that assigns the spots to their reference points unequivocally even if they are situated far outside their subaperture. For this assignment a spline function is extrapolated in successive steps of the iterative algorithm. The proposed method works in a single-shot technique and does not need any aid from mechanical devices. The reconstruction of a simulated steep aspherical wave front (~100lambda/mm slope) is described as well as experimental results of the measurement of a spherical wave front with a huge peak-to-valley value (~400lambda). The performance of the method is compared with the unwrapping method, which has been published before.     

Tearing the child apart: The contribution of narcissism, envy, and perverse modes of thought to child custody wars.

This article takes a psychoanalytic approach to questions usually considered to be matters of the family court system. The psychological effects of high-conflict divorce on children are well known, but what motivates their parents is less understood. Pathological narcissism, pathological envy, disavowal, and a perverse attitude toward reality can produce unending conflicts over visitation and custody. Fighting over seemingly insignificant matters can manage aggression and ward off psychic collapse. These families are frequently referred to coparenting counseling or psychoeducational groups; however, the author proposes that psychoanalytically oriented treatment can best address these parents' unconscious wishes to damage or destroy their own children and the perverse character structure that enables parents to negate their roles in tearing their children apart. (PsycINFO Database Record (c) 2010 APA, all rights reserved)