The crystal structure of trimethylarsine oxide dihydrate, (CH3)3AsO⋅2H2O, (TMAO dihydrate) has been solved using parallel tempering with the FOX software package and refined using synchrotron powder diffraction data obtained from beamline 08B1-1 at the Canadian Light Source. Rietveld refinement, performed with the software package GSASII, yielded orthorhombic lattice parameters of a = 13.3937(4) Å, b = 9.53025(30) Å, and c = 11.5951(3) Å (Z = 8, space group Pbca). The Rietveld refined structure was compared with density functional theory calculations performed with VASP and shows reasonable agreement. Arsenic K-edge X-ray absorption spectroscopy analysis also revealed additional information on the electronic structure of the arsenic atom within the TMAO dihydrate structure.

Metal–insulator–metal (MIM) resonant absorbers comprise a conducting ground plane, a thin dielectric, and thin separated metal top-surface structures. The dielectric SiO2 strongly absorbs near 9 µm wavelength and has correspondingly strong long-wave-infrared (LWIR) dispersion for the refractive index. This dispersion results in multiple absorption resonances spanning the LWIR, which can enhance broad-band sensitivity for LWIR bolometers. Similar considerations apply to silicon nitride Si3N4. TiO2 and AlN have comparatively low dispersion and give simple single LWIR resonances. These dispersion-dependent features for infrared MIM devices are demonstrated by experiment, electrodynamic simulation, and an analytic model based on standing waves.

Foraminiferal analyses of 404 contiguous samples, supported by diatom, lithologic, geochronologic and seismic data, reveal both rapid and gradual Holocene paleoenvironmental changes in an 8.21-m vibracore taken from southern Pamlico Sound, North Carolina. Data record initial flooding of a latest Pleistocene river drainage and the formation of an estuary 9000 yr ago. Estuarine conditions were punctuated by two intervals of marine influence from approximately 4100 to 3700 and 1150 to 500 cal yr BP. Foraminiferal assemblages in the muddy sand facies that accumulated during these intervals contain many well-preserved benthic foraminiferal species, which occur today in open marine settings as deep as the mid shelf, and significant numbers of well-preserved planktonic foraminifera, some typical of Gulf Stream waters. We postulate that these marine-influenced units resulted from temporary destruction of the southern Outer Banks barrier islands by hurricanes. The second increase in marine influence is coeval with increased rate of sea-level rise and a peak in Atlantic tropical cyclone activity during the Medieval Climate Anomaly. This high-resolution analysis demonstrates the range of environmental variability and the rapidity of coastal change that can result from the interplay of changing climate, sea level and geomorphology in an estuarine setting.

Cosmic radiation is capable of depositing significant quantities of energy and momentum in gravitational wave antennas at times that will generally be random with respect to gravitational signals. Such cosmic ray effects may generate noise signals at detectable levels compared to antenna design thresholds at rates of a few per year but, since antennas will not be capable of absorbing all the cosmic ray energy, it should be readily possible to construct vetoing cosmic ray detectors. For proposed interferometer antennas, a deposition of a few hundred GeV will produce a detectable noise signal and the veto will require about 100 MeV of energy deposition outside the antenna. We consider here some of the principles involved in the generation of gravitational antenna noise by cosmic ray particles and we describe a veto system to be installed at the Perth gravitational wave observatory.

A number of sophisticated modelling approaches are available to investigate potential associations between antimicrobial use (AMU) and resistance (AMR) in animal health settings. All have their advantages and disadvantages, making it unclear as to which model is most appropriate. We used advanced regression modelling to investigate AMU-AMR associations in faecal non-type-specific Escherichia coli (NTSEC) isolates recovered from 275 pens of feedlot cattle. Ten modelling strategies were employed to investigate AMU associations with resistance to chloramphenicol, ampicillin, sulfisoxazole, tetracycline and streptomycin. Goodness-of-fit statistics did not show a consistent advantage for any one model type. Three AMU-AMR associations were significant in all models. Recent parenteral tetracycline use increased the odds of finding tetracycline-resistant NTSEC [odds ratios (OR) 1·1–3·2]; recent parenteral sulfonamide use increased the odds of finding sulfisoxazole-resistant NTSEC (OR 1·4–2·5); and recent parenteral macrolide use decreased the odds of recovering ampicillin-resistant NTSEC (OR 0·03–0·2). Other results varied markedly depending on the modelling approach, emphasizing the importance of exploring and reporting multiple modelling methods based on a balanced consideration of important factors such as study design, mathematical appropriateness, research question and target audience.

Since the mid-1960s, agricultural economists have given much attention to research on farm-firm growth. One procedure used in this type of research has been multiperiod linear programming models, e.g. [1, 6, 9, 11, 14, 17]. Several researchers using the multiperiod linear programming framework have compared optimizing criteria. Generally, comparisons were made between maximizing some type of present value criterion and maximizing net worth at the end of the planning horizon. The different assumptions associated with the two maximizing criteria have resulted in different optimal growth patterns.

The production of feeder pigs as a cash commodity has been widespread in the southeastern U.S. during the past several years. One indication of the extent of marketing pigs at this intermediate stage is the fact that in 1979, 41 percent of the total Tennessee pig crop was sold through organized feeder pig sales (Rawls). This specialized production is continuing in many areas of the Southeast, although a trend has emerged that has more producers holding feeder pigs and feeding them to market weight.

Many archaeological sites along coastlines and rivers contain large quantities of marine and riverine bivalve shell. Often shell is the only datable organic material available to determine radiocarbon age estimates of features and to build regional chronologies. Shell is difficult to date accurately because of reservoir effects, and archaeologists have avoided it despite its abundance. If reservoir effects are understood, shell can provide accurate radiocarbon age estimates. This report provides an example using regression relations computed from radiocarbon assays of paired shelll charcoal samples from archaeological sites along the middle and lower Snake River, Northwestern North America.

Specific roles of individual CDPKs vary, but in general they mediate essential biological functions necessary for parasite survival. A comparative analysis of the structure-activity relationships (SAR) of Neospora caninum, Eimeria tenella and Babesia bovis calcium-dependent protein kinases (CDPKs) together with those of Plasmodium falciparum, Cryptosporidium parvum and Toxoplasma gondii was performed by screening against 333 bumped kinase inhibitors (BKIs). Structural modelling and experimental data revealed that residues other than the gatekeeper influence compound–protein interactions resulting in distinct sensitivity profiles. We subsequently defined potential amino-acid structural influences within the ATP-binding cavity for each orthologue necessary for consideration in the development of broad-spectrum apicomplexan CDPK inhibitors. Although the BKI library was developed for specific inhibition of glycine gatekeeper CDPKs combined with low inhibition of threonine gatekeeper human SRC kinase, some library compounds exhibit activity against serine- or threonine-containing CDPKs. Divergent BKI sensitivity of CDPK homologues could be explained on the basis of differences in the size and orientation of the hydrophobic pocket and specific variation at other amino-acid positions within the ATP-binding cavity. In particular, BbCDPK4 and PfCDPK1 are sensitive to a larger fraction of compounds than EtCDPK1 despite the presence of a threonine gatekeeper in all three CDPKs.

The study objective was to use Bayesian latent class analysis to evaluate the accuracy of susceptibility test results obtained from disk diffusion and broth microdilution using bacteria recovered from beef feedlot cattle. Isolates of Escherichia coli and Mannheimia haemolytica were tested for susceptibility to ampicillin, ceftiofur, streptomycin, sulfisoxazole, tetracycline, and trimethoprim-sulfamethoxazole. Results showed that neither testing method was always or even generally superior to the other. Specificity (ability to correctly classify non-resistant isolates) was extremely high for both testing methods, but sensitivity (ability to correctly classify resistant isolates) was lower, variable in the drugs evaluated, and variable between the two bacterial species. Predictive values estimated using Bayesian Markov chain Monte Carlo models showed that the ability to predict true susceptibility status was equivalent for test results obtained with the two testing methods for some drugs, but for others there were marked differences between results obtained from disk diffusion and broth microdilution tests.

Although the compartmentalization of poultry industry components has substantial economic implications, and is therefore a concept with huge significance to poultry industries worldwide, the current requirements for compartment status are generic to all OIE member countries. We examined the consequences for potential outbreaks of highly pathogenic avian influenza in the British poultry industry using a metapopulation modelling framework. This framework was used to assess the effectiveness of compartmentalization relative to zoning control, utilizing empirical data to inform the structure of potential epidemiological contacts within the British poultry industry via network links and spatial proximity. Conditions were identified where, despite the efficient isolation of poultry compartments through the removal of network-mediated links, spatially mediated airborne spread enabled spillover of infection with nearby premises making compartmentalization a more ‘risky’ option than zoning control. However, when zoning control did not effectively inhibit long-distance network links, compartmentalization became a relatively more effective control measure than zoning. With better knowledge of likely distance ranges for airborne spread, our approach could help define an appropriate minimum inter-farm distance to provide more specific guidelines for compartmentalization in Great Britain.

Human campylobacteriosis exhibits a distinctive seasonality in temperate regions. This paper aims to identify the origins of this seasonality. Clinical isolates [typed by multi-locus sequence typing (MLST)] and epidemiological data were collected from Scotland. Young rural children were found to have an increased burden of disease in the late spring due to strains of non-chicken origin (e.g. ruminant and wild bird strains from environmental sources). In contrast the adult population had an extended summer peak associated with chicken strains. Travel abroad and UK mainland travel were associated with up to 17% and 18% of cases, respectively. International strains were associated with chicken, had a higher diversity than indigenous strains and a different spectrum of MLST types representative of these countries. Integrating empirical epidemiology and molecular subtyping can successfully elucidate the seasonal components of human campylobacteriosis. The findings will enable public health officials to focus strategies to reduce the disease burden.

Representatives of the families Braconidae and Pteromalidae were present in association with broods of Ips pini Say and Ips perroti Sw. The identifications and information on distribution and hosts were kindly supplied by O. Peck and W. R. M. Mason of the Systematic Entomology Unit in Ottawa. Additional information on hosts and distribution were obtained from Hymenoptera of America by Muesebeck, Krombein, Towns, et al. (1951).

Studies were made on the distribution and survival of the mountain pine beetle over the lower stem of lodgepole pine. The relationship between density of attack and subsequent total length of egg galleries was examined as was the relationship between number of exit holes and number of emerging beetles. The influence on brood survival of tree diameter, density of egg galleries, moisture content of the outer sapwood, lethal temperatures, resinosis in the subcortical region, predators, and parasites is described. Survival is compared between broods established during different flights in the same year. The optimum weather conditions for brood survival are discussed.

The biology of the mountain pine beetle was studied in 1956 and 1957 near Invermere, in the East Kootenay region of British Columbia. The host tree was lodgepole pine (Pinus contorta var. latifolia Engelm.). The technique used permitted direct observation of mating, egg laying, and gallery construction. The sex ratio was also investigated under natural conditions and in cages. The most important previous work on the biology of this insect was done by De Leon, Bedard, and Terrell (1934).

Studies of the mountain pine beetle by DeLeon (1934), Evenden et al. (1943), Hopping and Mathers (1945), have shown that females frequently establish more than one egg gallery each season, Recent studies by the author indicate that females commonly leave their first egg galleries after a period of 2-3 weeks and fly to another tree where the second egg galleries are established.

This paper deals with the influence of bark moisture and temperature on the hehaviour of the egg-laying female within the host. Fecundity of the insect will he discussed, as well as internal changes associated with the behavioural pattern. The life-cycle, brood development, and time of flight was described in Part I of the present series. The behaviour during mating, egg laying, and gallery construction were described earlier (Reid 1958b).

This investigation was carried out to determine and explain some of the major factors underlying the variability in concentration of certain bark beetles in slash laid down under different cutting systems. Little is known on the life histories and natural control factors of many of the bark beetles inhabiting lodgepole pine (Pinus contorta Dougl. var latifolia Engelm.) and on the effect which different methods of logging have on the insects. Flash outbreaks in lodgepole pine stands frequently result from the breeding of certain bark beetles in slash remaining after logging operations. The opportunity to carry out this investigation was presented to the Calgary Laboratory in 1952, when the Federal Forest Service initiated studies on selectively cut lodgepole pine. This eventually became a co-operative project between the Federal Forest Service, Department of Northern Affairs and National Resources, and the Calgary Laboratories of Forest Zoology and Forest Pathology of the Division of Forest Biology.