Investigation of relationships between linears, tonal and hazy anomalies, and petroleum production in the Williston Basin: An ERTS approach

There are no author-identified significant results in this report

Methods and Costs for Pond-Catchment Rehabilitation on the Borana Plateau

The Borana Plateau is an important rangeland for Ethiopia. One key limitation for people and livestock is lack of drinking water. Hundreds of ponds are important water sources for most of the year. Pond catchments are poorly managed because livestock access is uncontrolled. Catchments are stripped bare of vegetation due to trampling and heavy grazing, and unprotected soil is prone to erosion. When the rains come the ponds quickly fill with sediment. Sedimentation reduces pond holding capacity and much labor is required to clean them out. As part of a pilot research project we rehabilitated four ponds and their immediate catchment using a combination of: (1) Perimeter bush-fencing to confine livestock access to a few narrow corridors leading to the water\u27s edge; (2) erosion control using dams and trenches to capture sediment prior to it entering the ponds; and (3) pond de-sedimentation using human labor. In tandem these methods have completely renovated the four sites in less than two years and could be adopted by the pastoralists. Here we report how we implemented each method as well as estimate the total cost of rehabilitation. Overall, the average cost to rehabilitate one seven-hectare pond catchment was 283, 045 Ethiopian Birr (or USD $14,152) including cash and in-kind sources. Costs were almost entirely labor. The largest outlay was for de-sedimentation at 87 percent of total costs on average, followed by erosion control (9 percent) and bush fencing (4 percent). If all 162 ponds in our study area were rehabilitated the cost would exceed 46 million Birr; this might be defrayed if communities can donate some of the labor. The high cost of rehabilitation illustrates that poor catchment management has major economic consequences that undermine system sustainability. Cost data also reveal that a small investment in preventing sedimentation via bush-fencing, grazing management, and erosion control would yield high returns in terms of reducing the need for regular, and expensive de-sedimentation via manual labor

An avalanche-photodiode-based photon-number-resolving detector

Avalanche photodiodes are widely used as practical detectors of single photons.1 Although conventional devices respond to one or more photons, they cannot resolve the number in the incident pulse or short time interval. However, such photon number resolving detectors are urgently needed for applications in quantum computing,2-4 communications5 and interferometry,6 as well as for extending the applicability of quantum detection generally. Here we show that, contrary to current belief,3,4 avalanche photodiodes are capable of detecting photon number, using a technique to measure very weak avalanches at the early stage of their development. Under such conditions the output signal from the avalanche photodiode is proportional to the number of photons in the incident pulse. As a compact, mass-manufactured device, operating without cryogens and at telecom wavelengths, it offers a practical solution for photon number detection.Comment: 12 pages, 4 figure

Quantification of the Ecological Resilience of Drylands Using Digital Remote Sensing

Drylands cover 41% of the terrestrial surface and support > 36% of the world's population. However, the magnitude of dryland degradation is unknown at regional and global spatial scales and at 15-30-yr temporal scales. Historical archives of > 30 yr of Landsat satellite imagery exist and allow local to global monitoring and assessment of a landscape's natural resources in response to climatic events and human activities. Vegetation indices (VIs), i.e., proxies of vegetation characteristics such as phytomass, can be derived from the spectral properties of Landsat imagery. A dynamical systems analysis method called mean-variance analysis can be used to describe and quantify dynamic regimes of VI response to disturbance using characteristics of ecological resilience, particularly amplitude and malleability, from a change detection perspective. Amplitude is the magnitude of response of a VI to a disturbance; malleability is the degree of recovery of a resource after a disturbance. Spatially aggregate and spatially explicit (image) differencing are methods whereby a VI image or statistic from one time period is subtracted from a VI image or statistic from another time period. To illustrate this method, we used a time series of Landsat imagery from 1972 to 1987 to measure the response of vegetation communities that are managed by subsistence agropastoral communities to the severe 1982-1984 El Niño-induced drought on the Bolivian Altiplano. We found that the entire landscape had decreased vegetation cover, increased variance (diagnostic of a regime shift), and thus, increased susceptibility to soil erosion during the drought. The wet meadow vegetation cover class had the lowest amplitude and thus the most resilience relative to other vegetation cover classes. This response identified the wet meadow as a key resource, as well as a harbinger of climate change for agropastoral communities in areas where drought is an endemic stressor

Even perturbations of self-similar Vaidya space-time

We study even parity metric and matter perturbations of all angular modes in self-similar Vaidya space-time. We focus on the case where the background contains a naked singularity. Initial conditions are imposed describing a finite perturbation emerging from the portion of flat space-time preceding the matter-filled region of space-time. The most general perturbation satisfying the initial conditions is allowed impinge upon the Cauchy horizon (CH), whereat the perturbation remains finite: there is no ``blue-sheet'' instability. However when the perturbation evolves through the CH and onto the second future similarity horizon of the naked singularity, divergence necessarily occurs: this surface is found to be unstable. The analysis is based on the study of individual modes following a Mellin transform of the perturbation. We present an argument that the full perturbation remains finite after resummation of the (possibly infinite number of) modes.Comment: Accepted for publication in Physical Review D, 27 page

Effect of omitting post-milking teat disinfection on the mastitis infection rate of dairy cows over a full lactation

Abstract Fifty-six autumn calving Holstein-Friesian dairy cows were milked as one herd over a complete lactation. Right-sided teats were disinfected post-milking by submersing teats in a chlorohexadine solution, while teat disinfectant was omitted on left-sided teats. Milk samples were taken from individual quarters to measure SCC on thirteen occasions during the lactation. Mean somatic cell count was lower (P<0.01) in milk from disinfected compared to non-disinfected quarters over the full lactation. The number of clinical infections was also significantly lower (P<0.001) in disinfected compared to nondisinfected quarters. Omitting teat disinfection also resulted in a higher (P<0.01) number of non-haemolytic staphylococci and Staphylococcus aureus pathogens in those quarters compared to disinfected quarters

The acquisition of Sign Language: The impact of phonetic complexity on phonology

Research into the effect of phonetic complexity on phonological acquisition has a long history in spoken languages. This paper considers the effect of phonetics on phonological development in a signed language. We report on an experiment in which nonword-repetition methodology was adapted so as to examine in a systematic way how phonetic complexity in two phonological parameters of signed languages — handshape and movement — affects the perception and articulation of signs. Ninety-one Deaf children aged 3–11 acquiring British Sign Language (BSL) and 46 hearing nonsigners aged 6–11 repeated a set of 40 nonsense signs. For Deaf children, repetition accuracy improved with age, correlated with wider BSL abilities, and was lowest for signs that were phonetically complex. Repetition accuracy was correlated with fine motor skills for the youngest children. Despite their lower repetition accuracy, the hearing group were similarly affected by phonetic complexity, suggesting that common visual and motoric factors are at play when processing linguistic information in the visuo-gestural modality