38,270 research outputs found
Ecologic Relationships Between Bacteria and Algae in Mass Culture
Ecological relationships between bacteria and algae in mass cultur
Direction discriminating hearing aid system
A visual display was developed for people with substantial hearing loss in either one or both ears. The system consists of three discreet units; an eyeglass assembly for the visual display of the origin or direction of sounds; a stationary general purpose noise alarm; and a noise seeker wand
Plant Processes and Applications
Introduction-- Growth of Plants-- Photosynthesis-- Controlled Photosynthesis-- Not
Correlation length and negative phase velocity in isotropic dielectric-magnetic materials
A composite material comprising randomly distributed spherical particles of
two different isotropic dielectric-magnetic materials is homogenized using the
second-order strong-property-fluctuation theory in the long-wavelength
approximation. Whereas neither of the two constituent materials by itself
supports planewave propagation with negative phase velocity (NPV), the
homogenized composite material (HCM) can. The propensity of the HCM to support
NPV propagation is sensitive to the distributional statistics of the
constituent material particles, as characterized by a two--point covariance
function and its associated correlation length. The scope for NPV propagation
diminishes as the correlation length increases
An investigation into the accuracy of industrial measurements as practised by the engineering industries in the Teesside area
October, 1966 was the starting date of "Quality and Reliability Year" for British Industry. The author believes that, after the design stage, the greatest contribution to quality and reliability lies in being able to maintain close dimensional control during the manufacturing process. This investigation was carried out with the intention of providing the engineering industries in the Teesside area with a realistic picture of the accuracy of engineering measurements carried out in the workshops and inspection departments of the respective individual firms. The results follow the general pattern set by two similar investigations carried out by the National Physical Laboratory, (N.P.L.), some years ago, but indicate a wider spread of individual errors about the mean size, and correspondingly larger standard deviation. It also indicates that very few firms in the area possess much more sophisticated equipment than micrometers, dial gauges, and slip gauges, and even these are, in the main, neglected and badly maintained. Optical instruments are almost non-existent. The operatives estimation of their accuracy of measurement varies from the N.P.L. findings in that a number are more optimistic, but in general there is a wider and more uniform spread of opinion. The firm's assessments of their employees' capabilities also tend to be optimistic, and in some cases suggest that they do not possess a great deal of knowledge about the ability of their workmen. Another disturbing aspect is the comparison between standard deviation and the tolerances laid down in B.S. 1916, "Limits and Fits for Engineering". This shows that either the tolerances specified by the British Standard are unrealistic, or that industry in this area has difficulty in working to tolerances closer than I.T.7. The investigation has shown that working conditions, and the training of operatives in principles of metrology, leave much to be desired, although the latter point appears to be being remedied since the investigation took place
Threshold concepts and metalearning capacity
This study operationalises the empowering concept of metalearning in the specific context of engagement with a threshold concept. An experience of metalearning was constituted in two parts. First students' awareness of themselves as learners is prompted by, and focuses on, a learning profile that is generated online through the completion of the Reflections on Learning Inventory (RoLI). Second, students are given an opportunity to interpret their respective profiles and write a short and undirected reflective account of their interpretation. The second part of the experience focuses not only on students' awareness but also on their capacity to control their future learning on the basis of their heightened awareness.
The price of sex: condom use and the determinants of the price of sex among female sex workers in eastern zimbabwe.
Background. Higher prices for unprotected sex threaten the high levels of condom use that contributed to the decline in Zimbabwe's human immunodeficiency virus (HIV) epidemic. To improve understanding of financial pressures competing against safer sex, we explore factors associated with the price of commercial sex in rural eastern Zimbabwe. Methods. We collected and analyzed cross-sectional data on 311 women, recruited during October–December 2010, who reported that they received payment for their most-recent or second-most-recent sex acts in the past year. Zero-inflated negative binomial models with robust standard errors clustered on female sex worker (FSW) were used to explore social and behavioral determinants of price. Results. The median price of sex was 5–10 (IQR, 15) per act. Amounts paid in cash and commodities did not differ significantly. At the most-recent sex act, more-educated FSWs received 30%–74% higher payments. Client requests for condom use significantly predicted protected sex (P < .01), but clients paid on average 42.9% more for unprotected sex. Conclusions. Within a work environment where clients' preferences determine condom use, FSWs effectively use their individual capital to negotiate the terms of condom use. Strengthening FSWs' preferences for protected sex could help maintain high levels of condom use
The Taurus Boundary of Stellar/Substellar (TBOSS) Survey I: far-IR disk emission measured with Herschel
With Herschel/PACS 134 low mass members of the Taurus star-forming region
spanning the M4-L0 spectral type range and covering the transition from low
mass stars to brown dwarfs were observed. Combining the new Herschel results
with other programs, a total of 150 of the 154 M4-L0 Taurus members members
have observations with Herschel. Among the 150 targets, 70um flux densities
were measured for 7 of the 7 ClassI objects, 48 of the 67 ClassII members, and
3 of the 76 ClassIII targets. For the detected ClassII objects, the median 70um
flux density level declines with spectral type, however, the distribution of
excess relative to central object flux density does not change across the
stellar/substellar boundary in the M4-L0 range. Connecting the 70um TBOSS
values with the results from K0-M3 ClassII members results in the first
comprehensive census of far-IR emission across the full mass spectrum of the
stellar and substellar population of a star-forming region, and the median flux
density declines with spectral type in a trend analogous to the flux density
decline expected for the central objects. SEDs were constructed for all TBOSS
targets covering the optical to far-IR range and extending to the submm/mm for
a subset of sources. Based on an initial exploration of the impact of different
physical parameters; inclination, scale height and flaring have the largest
influence on the PACS flux densities. From the 24um to 70um spectral index of
the SEDs, 5 new candidate transition disks were identified. The steep 24um to
70um slope for a subset of 8 TBOSS targets may be an indication of truncated
disks in these systems.Two examples of mixed pair systems that include
secondaries with disks were measured. Finally, comparing the TBOSS results with
a Herschel study of Ophiuchus brown dwarfs reveals a lower fraction of disks
around the Taurus substellar population.Comment: 64 pages, 33 figures, 12 tables, accepted for publication in A&
Threshold Corrections in Precision LHC Physics: QED otimes QCD
With an eye toward LHC processes in which theoretical precisions of 1 percent
are desired, we introduce the theory of the simultaneous YFS resummation of QED
and QCD to compute the size of the expected resummed soft radiative threshold
effects in precision studies of heavy particle production at the LHC. Our
results show that both QED and QCD soft threshold effects must be controlled to
be on the conservative side to achieve such precision goals.Comment: 4 pages, no figures; presented by B.F.L. Ward in DPF200
Strain driven anisotropic magnetoresistance in antiferromagnetic LaSrMnO
We investigate the effects of strain on antiferromagntic (AFM) single crystal
thin films of LaSrMnO (x = 0.6). Nominally unstrained
samples have strong magnetoresistance with anisotropic magnetoresistances (AMR)
of up to 8%. Compressive strain suppresses magnetoresistance but generates AMR
values of up to 63%. Tensile strain presents the only case of a metal-insulator
transition and demonstrates a previously unreported AMR behavior. In all three
cases, we find evidence of magnetic ordering and no indication of a global
ferromagnetic phase transition. These behaviors are attributed to epitaxy
induced changes in orbital occupation driving different magnetic ordering
types. Our findings suggest that different AFM ordering types have a profound
impact on the AMR magnitude and character.Comment: http://dx.doi.org/10.1063/1.489242
- …