Prospects for food and agriculture in 1975

Agriculture ; Food industry and trade

Outlook for food and agriculture - 1980

Agriculture ; Food prices

The 1974 outlook for food and agriculture

Food industry and trade ; Agriculture

Renormalization of four-fermion operators for higher twist calculations

The evaluation of the higher twist contributions to Deep Inelastic Scattering amplitudes involves a non trivial choice of operator bases for the higher orders of the OPE expansion of the two hadronic currents. In this talk we discuss the perturbative renormalization of the four-fermion operators that appear in the above bases.Comment: LATTICE98(matrixelement), 3 page

Higher-twist contributions to the Structure Functions coming from 4-fermion operators

We evaluate the contribution of a class of higher-twist operators to the lowest moment of the Structure Functions, by computing appropriate matrix elements of six four-fermion operators in the quenched approximation. Their perturbative renormalization constants and mixing coefficients are calculated in the 't Hooft-Veltman scheme of dimensional regularization, using codes written in the algebraic manipulation computer language FORM.Comment: Talk presented at LATTICE99(matrix elements), Pisa (Italy), June 29 - July 3; 3 pages; to be published in Nucl. Phys. B (Proc. Suppl.

Triggering and modulation of geyser eruptions in Yellowstone National Park by earthquakes, earth tides, and weather

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 1718–1737, doi:10.1002/2013JB010803.We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual geyser IBE variability is dominated by internal processes and interaction with other geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.K. Luttrell and S. Hurwitz were supported by the USGS Volcano Hazards Program, and Michael Manga was supported by NSF grant EAR1114184.2014-09-0

Triggering and modulation of geyser eruptions in Yellowstone National Park by earthquakes, earth tides, and weather

Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Solid Earth 119 (2014): 1718–1737, doi:10.1002/2013JB010803.We analyze intervals between eruptions (IBEs) data acquired between 2001 and 2011 at Daisy and Old Faithful geysers in Yellowstone National Park. We focus our statistical analysis on the response of these geysers to stress perturbations from within the solid earth (earthquakes and earth tides) and from weather (air pressure and temperature, precipitation, and wind). We conclude that (1) the IBEs of these geysers are insensitive to periodic stresses induced by solid earth tides and barometric pressure variations; (2) Daisy (pool geyser) IBEs lengthen by evaporation and heat loss in response to large wind storms and cold air; and (3) Old Faithful (cone geyser) IBEs are not modulated by air temperature and pressure variations, wind, and precipitation, suggesting that the subsurface water column is decoupled from the atmosphere. Dynamic stress changes of 0.1−0.2 MPa resulting from the 2002 M-7.9 Denali, Alaska, earthquake surface waves caused a statistically significant shortening of Daisy geyser's IBEs. Stresses induced by other large global earthquakes during the study period were at least an order of magnitude smaller. In contrast, dynamic stresses of >0.5 MPa from three large regional earthquakes in 1959, 1975, and 1983 caused lengthening of Old Faithful's IBEs. We infer that most subannual geyser IBE variability is dominated by internal processes and interaction with other geysers. The results of this study provide quantitative bounds on the sensitivity of hydrothermal systems to external stress perturbations and have implications for studying the triggering and modulation of volcanic eruptions by external forces.K. Luttrell and S. Hurwitz were supported by the USGS Volcano Hazards Program, and Michael Manga was supported by NSF grant EAR1114184.2014-09-0

Mycoplasmal conjunctivitis in wild songbirds: the spread of a new contagious disease in a mobile host population.

A new mycoplasmal conjunctivitis was first reported in wild house finches (Carpodacus mexicanus) in early 1994. The causative agent was identified as Mycoplasma gallisepticum (MG), a nonzoonotic pathogen of poultry that had not been associated with disease in wild songbirds. Since the initial observations of affected house finches in the mid-Atlantic region, the disease has become widespread and has been reported throughout the eastern United States and Canada. By late 1995, mycoplasmal conjunctivitis had spread to an additional species, the American goldfinch (Carduelis tristis). This new disease exemplifies the rapid spread of a pathogen following introduction into a mobile wildlife population and provides lessons that may apply to emerging human diseases

Developing novel photocatalytic cementitious permeable pavements for depollution of contaminants and impurities in urban cities

Photocatalyst such as Titanium Dioxide (TiO2) has been recently introduced as a nanoparticle into cementitious permeable pavements. Combining photocatalytic compounds within concrete permeable pavements can aid with depollution of several contaminants found in urban water streams and air impurities. This paper presents research carried out at the Uni-versity of Greenwich, UK using photocatalytic concrete with varying percentages of TiO2 (0 %, 1% and 5%) to assess the levels depollution which can be achieved.Concrete samples were testing against the degradation of 2, 4-Dichlorophenoxyacetic Acid, a harmful chemical found in herbicides. This advanced oxidation process can aid in the re-duction of urban pollution from an air and water perspective, improving sustainability for urban cities. Self-cleaning benefits of photocatalytic concrete permeable pavements can be used to keep urban infrastructure cleaner and more aesthetically pleasing. Experimental tests were carried out on the characterisation of inorganics through X-Ray diffraction and Fourier Transform Infrared Spectroscopy to ensure that the structures of the concrete samples were not altered by addition of the na-noparticles (photocatalyst). Experimental results were compared to that found in previous literature and confirmed that the addition of 5% TiO2 did not affect the structure of the concrete samples and can be a viable option used in urban infrastruc-ture such as permeable pavements

ND2 as an Additional Genetic Marker to Improve Identification of Diving Ducks Involved in Bird Strikes

Knowing the exact species of birds involved in damaging collisions with aircraft (bird strikes) is paramount to managing and preventing these types of human–wildlife conflicts. While a standard genetic marker, or DNA barcode (mitochondrial DNA gene cytochrome-c oxidase 1, or CO1), can reliably identify most avian species, this marker cannot distinguish among some closely related species. Diving ducks within the genus Aythya are an example of congeneric waterfowl involved in bird strikes where several species pairs cannot be reliably identified with the standard DNA barcode. Here, we describe methods for using an additional genetic marker (mitochondrial DNA gene NADH dehydrogenase subunit 2, or ND2) for identification of 9 Aythya spp. Gene-specific phylogenetic trees and genetic distances among taxa reveal that ND2 is more effective than CO1 at genetic identification of diving ducks studied here. Compared with CO1, the ND2 gene tree is more statistically robust, has a minimum of 1.5 times greater genetic distance between sister clades, and resolves paraphyly in 2 clades. While CO1 is effective for identification of most bird strike cases, this study underscores the value of targeted incorporation of additional genetic markers for species identification of taxa that are known to be problematic using standard DNA barcoding