Evacuated-tube directional-radiating cooling system

A new type of radiative cooling system is described. The radiator makes use of nonimaging optics and evacuated-tube technology to radiate significant amounts of heat to the 3 K environment of outer space. The nonimaging optics are used to direct the radiation overhead, through the most transparent part of the 8–13 μm atmospheric window. The required optical concentration is small, and relatively simple mirror geometries are possible. The evacuated-tube technology is used to attain storage temperatures at or below the freezing point, even when dewpoint temperatures are well above the freezing point.     

Annotations and the collaborative digital library: Effects of an aligned annotation interface on student argumentation and reading strategies

Recent research on annotation interfaces provides provocative evidence that anchored, annotation-based discussion environments may lead to better conversations about a text. However, annotation interfaces raise complicated tradeoffs regarding screen real estate and positioning. It is argued that solving this screen real estate problem requires limiting the number of annotations displayed to users. In order to understand which annotations have the most learning value for students, this paper presents two complementary studies examining the effects of annotations on students performing a reading-to-write task. The first study used think-aloud protocols and a within-subjects methodology, finding that annotations appeared to provoke students to reflect more critically upon the primary text. This effect was particularly strong when students encountered pairs of annotations presenting different viewpoints on the same section of text. Student interviews suggested that annotations were most helpful when they caused the reader to consider and weigh conflicting viewpoints. The second study used a between-subjects methodology and a more naturalistic task to provide complementary evidence that annotations encourage more reflective responses to a text. This study found that students who received annotated materials both perceived themselves and were perceived by instructors as less reliant on unreflective summary strategies than students who received the same content but in a different format. These findings indicate that the learning value of an annotation lies in its ability to provoke students to consider and weigh new perspectives on the primary text. When selected effectively, annotations provide a critical scaffolding that can support students’ critical thinking and argumentation activities. Collaborative digital libraries and applications for the Web 2.0 should be designed with this learning framework in mind.     

Adaptation and validation of antibody-ELISA using dried blood spots on filter paper for epidemiological surveys of tsetse-transmitted trypanosomosis in cattle

The indirect enzyme-linked immunosorbent assay (ELISA) for the detection of anti-trypanosomal antibodies in bovine serum was adapted for use with dried blood spots on filter paper. Absorbance (450 nm) results for samples were expressed as percent positivity, i.e. percentage of the median absorbance result of four replicates of the strong positive control serum. The antibody-ELISA was evaluated in Zambia for use in epidemiological surveys of the prevalence of tsetse-transmitted bovine trypanosomosis. Known negative samples (sera, n = 209; blood spots, n = 466) were obtained from cattle from closed herds in tsetse-free areas close to Lusaka. Known positive samples (sera, n = 367; blood spots, n = 278) were obtained from cattle in Zambia's Central, Lusaka and Eastern Provinces, diagnosed as being infected with Trypanosoma brucei, T. congolense, or T. vivax using the phase-contrast buffy-coat technique or Giemsa-stained thick and thin blood smears. For sera (at a cut-off value of 23.0% positivity) sensitivity and specificity were 86.1 and 95.2%, respectively. For bloodspots (at a cut-off value of 18.8% positivity) sensitivity and specificity were 96.8 and 95.7%, respectively. The implications of persistence of antibodies following treatment or self-cure are discussed.     

The highly inappropriate calibrations of statistical significance.

Comments that an article had used the term "highly significant" to describe an empirical result. The author considers such a modifier to statistical significance is entirely inappropriate on 2 counts. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

In Situ Investigation of TCP Phase Formation,Stress Relaxation and γ/γ′ Lattice Misfit Evolution in Fourth Generation Single Crystal Ni-Base Superalloys by X-Ray High Temperature Diffraction

Metallurgical and Materials Transactions A - In nickel-based superalloys, the lattice misfit between the γ and γ′ phases and the propensity to TCP phase formation at service...     

Efficient verifiably encrypted signatures from lattices

Verifiably encrypted signature schemes can convince a verifier that a given ciphertext is an encryption of an ordinary signature on a given message and the ordinary signature can be recovered by the third party, called adjudicator. In 2010, Rückert et al. proposed a general construction for the verifiably encrypted signatures, and then, they also showed that there exist the lattice-based verifiably encrypted signature schemes. Their constructions are very insightful, but their schemes need an extra adjudication setup phase and Merkle trees, so they have large parameters and keys, that is, they are inefficient. Also, their schemes provide only the limited signature capacity because the signing keys should be reissued after generating \(k\) th verifiably encrypted signatures. To overcome the weaknesses of Rückert et al.’s scheme, we construct a verifiably encrypted signature scheme based on the hard lattice problems. Our scheme provides the full functionality, i.e., the signatures can be generated without any limitations and does not need any extra adjudication setup phases. Moreover, the size of the secret keys in our scheme is constant. Our scheme provides unforgeability, opacity, extractability, and abuse-freeness in the random oracle model.     

The effect of mixed mode I/III on crack evolution in brittle solids

A modification of Sommer's classical experiment [4] has been used to fracture rods of a brittle epoxy resin in mixed mode I/III stress conditions. The nucleation and growth of cracks in an increasing K _III/K _I stress field have been investigated, particularly in relation to the formation of river lines and the evolution of multiple cracks between river lines to form smooth helicoid surfaces. The fractographic features associated with the progressive development of river line patterns involving crack bowing at river line steps, interaction between arrays of cracks and the coalescence of river lines are described. As K _III/K _I increases the scale of the river line patterns increases but the patterns remain self similar. Using principles from differential geometry it is shown that helicoid surfaces can be generated entirely by crack evolution involving tilting without twiting.Emeritus Goldsmiths' Professor of Metallurgy, University of Cambridge, U.K.     

Determination of the average orientation of DNA in the octopus sperm Eledone cirrhossa through polarized light scattering

The coupled-dipole approximation has been used to model polarized light-scattering data obtained from the sperm of the octopus Eledone cirrhosa. Mueller scattering-matrix elements (which describe how a sample alters the intensity and degree of polarization of scattered light) were measured as a function of angle. The sample was modeled as a helical fiber believed to correspond to a DNA protein complex. It was necessary to propose an inherent anisotropy in the polarizability of the fiber in order to fit the data. The direction of the principle axes of the polarizability were determined by comparing the model with experimental data. The results suggest that the 2-nm DNA fibers are perpendicular to the thick fiber that defines the helical geometry of the octopus sperm head.