Detection system ensures positive alarm activation in digital message loss

Lost Word Detection System /LOWDS/ provides special identification for each error detection message transmitted from receiver to transmitter. The message is identified as an original message or an n-times retransmitted message so the receiver can detect where a retransmission request was not fulfilled and activate an alarm

Comparative Physiology of Birds

The structure and physiology of birds differs in many respects from that of mammals

Late development between the ages of 11 and 14

The thesis is concerned with pupils who on the evidence available at 11+ are rightly refused entry to a grammar school, but subsequently prove capable of profiting academically from education in such a school. Some recent researches are examined, and it is concluded that claims for highly successful prognosis at 11+ are not fully borne out by the evidence presented. An investigation in a boys' grammar school is reported. Over three years, this school admitted 10% of the age group at; 11 + , and a further 4% from the 12+ - 14+ age groups. Selection at 11+ was made on the basis of three equally weighted Moray House tests, but were not used for final selection. The failure rate for 11+ entrants, judged by third form results, is 25%, the same as for the late entrants. Among the latter were 32 who fell below the lower limit of a borderzone designed to include 95% of those whose true totals in the selection examination might have been equal to the pass mark. The failure rate for these sub-border-zone late entrants is also 25%, and some are judged to be potential university entrants. The successful sub-borderzone late entrants are numerically equal to 12% of the 11+ intake. Some of the most successful would still not have been admitted at 11+ even if the primary school assessments had been used in the selection procedure. This, with the average (uncorrected) 11+ - 14+ correlation for normal entrants of 0.355, emphasises the need for transfer facilities from secondary modern schools in the area. It is suggested that in the area concerned a verbal weakness, later remedied, is a common cause of the failure at 11+ of pupils who subsequently succeed in the grammar school

Understanding the Drivers of Urban Expansion: Case Study of Seville Province

Urban development has accelerated across the globe in recent decades. Much of this development has not been concentrated in cities, but has occurred as dispersed, low-density development outside of major centers but within their area of economic influence, along transport networks, in coastal areas, or close to areas of high natural value. This research focuses on the case study of the province of Seville, Spain, which has experienced notable urban expansion in recent years. We present a systems approach to model dependence between economic development and distribution of urban and non-urban land in this region from data collection to model validation. An extensive search of available indicators of socioeconomic development in this region has been carried out. We apply this data to create a generic statistical model of urban expansion, which links land-use patterns with population density and other indicators of economic growth. The model is tested across the whole Seville region and in its sub-regions to derive drivers of urban expansion in this territory

Manipulation of Light with Magneto-optic Stripe Domain Films

Magnetic diffraction grating materials, being developed to provide a simple means of deflecting light in a two dimensional, solid state fashion are discussed. The most promising material, for several applications, appears to be bismuth substituted iron garnet films in epitaxial form. Calculations indicate that deflection efficiency greater than 60% is possible in the near infrared region of the spectrum. Within the field of view of the deflector, measurements predict that 105 resolvable spots can be expected. Applications include: (1) general purpose deflection of free laser light, (2) image processing of extended sources such as transparencies, (3) programmable lensing, and (4) fiber optic matrix switching

The Effect of Fluorine on Blood and Respiration

Much interest has been manifested in fluorine during the past few years. This is due to two reasons: first, fluorine is found in several phosphatic mineral supplements, which are fed to farm animals ; and, second, fluorine has been found in drinking waters in this and many other countries of the world. The interest of the authors in fluorine dates from the discovery by Ostrem, Nelson, Greenwood, and Wilhelm of fluorine in the drinking waters of communities in the State of Iowa, with the resulting production of mottled enamel of the teeth. There can be no question that fluorine in excessive amounts in water causes damage to the teeth. Smith, Lantz, and Smith have produced considerable evidence that the presence of excessive fluorine in the drinking water will cause mottled enamel in man. The question naturally arises as to whether fluorine in water produces other harmful effects or pathological changes in the body, aside from the disturbance to the teeth

Dispersal Dynamics in a Wind-Driven Benthic System

Bedload and water column traps were used with simultaneous wind and water velocity measurements to study postlarval macrofaunal dispersal dynamics in Manukau Harbour, New Zealand. A 12-fold range in mean wind condition resulted in large differences in water flow (12-fold), sediment flux (285-fold), and trap collection of total number of individuals (95-fold), number of the dominant infaunal organism (84-fold for the bivalve Macomona liliana), and number of species (4-fold). There were very strong, positive relationships among wind condition, water velocity, sediment flux, and postlarval dispersal, especially in the bedload. Local density in the ambient sediment was not a good predictor of dispersal. Results indicate that postlarval dispersal may influence benthic abundance pat- terns over a range of spatial scales

Quantum gravity and the Coulomb potential

We apply a singularity resolution technique utilized in loop quantum gravity to the polymer representation of quantum mechanics on R with the singular -1/|x| potential. On an equispaced lattice, the resulting eigenvalue problem is identical to a finite difference approximation of the Schrodinger equation. We find numerically that the antisymmetric sector has an energy spectrum that converges to the usual Coulomb spectrum as the lattice spacing is reduced. For the symmetric sector, in contrast, the effect of the lattice spacing is similar to that of a continuum self-adjointness boundary condition at x=0, and its effect on the ground state is significant even if the spacing is much below the Bohr radius. Boundary conditions at the singularity thus have a significant effect on the polymer quantization spectrum even after the singularity has been regularized.Comment: 10 pages, 5 figures. v2: Minor presentational changes. One data point added in Table

Toward Empirical Constraints on the Global Redshifted 21 cm Brightness Temperature During the Epoch of Reionization

Preliminary results are presented from a simple, single-antenna experiment designed to measure the all-sky radio spectrum between 100 and 200 MHz. The system used an internal comparison-switching scheme to reduce non-smooth instrumental contaminants in the measured spectrum to 75 mK. From the observations, we place an initial upper limit of 450 mK on the relative brightness temperature of the redshifted 21 cm contribution to the spectrum due to neutral hydrogen in the intergalactic medium (IGM) during the epoch of reionization, assuming a rapid transition to a fully ionized IGM at a redshift of 8. With refinement, this technique should be able to distinguish between slow and fast reionization scenarios. To constrain the duration of reionization to dz > 2, the systematic residuals in the measured spectrum must be reduced to 3 mK.Comment: Submitted to ApJ. 9 pages including 6 figure