Recent developments in the characterization of superconducting films by microwaves

We describe and analyze selected surface impedance data recently obtained by different groups on cuprate, ruthenate and diboride superconducting films on metallic and dielectric substrates for fundamental studies and microwave applications. The discussion includes a first review of microwave data on MgB2, the weak-link behaviour of RABiTS-type YBa2Cu3O7-d tapes, and the observation of a strong anomalous power-dependence of the microwave losses in MgO at low temperatures. We demonstrate how microwave measurements can be used to investigate electronic, magnetic, and dielectric dissipation and relaxation in the films and substrates. The impact of such studies reaches from the extraction of microscopic information to the engineering of materials and further on to applications in power systems and communication technology.Comment: Invited contribution to EUCAS2001, accepted for publication in Physica C in its present for

Theory of the first-order isostructural valence phase transitions in mixed valence compounds YbIn_{x}Ag_{1-x}Cu_{4}

For describing the first-order isostructural valence phase transition in mixed valence compounds we develop a new approach based on the lattice Anderson model. We take into account the Coulomb interaction between localized f and conduction band electrons and two mechanisms of electron-lattice coupling. One is related to the volume dependence of the hybridization. The other is related to local deformations produced by f- shell size fluctuations accompanying valence fluctuations. The large f -state degeneracy allows us to use the 1/N expansion method. Within the model we develop a mean-field theory for the first-order valence phase transition in YbInCu_{4}. It is shown that the Coulomb interaction enhances the exchange interaction between f and conduction band electron spins and is the driving force of the phase transition. A comparison between the theoretical calculations and experimental measurements of the valence change, susceptibility, specific heat, entropy, elastic constants and volume change in YbInCu_{4} and YbAgCu_{4} are presented, and a good quantitative agreement is found. On the basis of the model we describe the evolution from the first-order valence phase transition to the continuous transition into the heavy-fermion ground state in the series of compounds YbIn_{1-x}Ag_{x}Cu_{4}. The effect of pressure on physical properties of YbInCu_{4} is studied and the H-T phase diagram is found.Comment: 17 pages RevTeX, 9 Postscript figures, to be submitted to Phys.Rev.

A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Radiosonde aerosol counter for vertical profiling of atmospheric dust

A low-cost, miniature aerosol particle counter has been developed, intended for use with balloon-borne meteorological radiosondes. It is particularly suitable for airborne mineral dust measurements. Ambient air is drawn into the counter using a diaphragm pump at a rate of 0.5 litre per minute. The counter detects particles in the airstream using a diode laser and a photodiode. Output from the photodiode is digitised into 5 size bins, with minimum particle diameters equivalent to 0.6, 1.4, 2.6, 5.4 and 10.6 micrometers. The counter is interfaced to a Vaisala RS92 radiosonde, which transmits data from the counter together with meteorological parameters and GPS-derived position to a ground based receiver at 1 Hz rate. Statistically significant particle size distributions can be obtained once a second for number concentrations down to about 100,000 particle per litre (within the measured size range), or correspondingly less at lower temporal resolutions. At the same time, the counter is capable of measuring dust number concentrations exceeding a million per litre without incurring significant errors. Soundings during the DREAME campaign in Kuwait (Ulanowski et al. EGU 2010, AS4.7) and on Cape Verde Islands (Nicoll et al. EGU 2010, AS4.7) provided dust concentration profiles with a typical vertical resolution of 4 m. Comparisons with integrated dust column size distribution measurements from AERONET sun photometers showed good agreement in two out of three cases where near-simultaneous retrievals were available. Optical thickness calculations based on the size distributions measured in Kuwait, with the assumption that the dust particles were prolate spheroids, agreed with the AERONET optical thickness at 675 nm to within 15%.Non peer reviewe

Atmospheric dust charging, vertical profiles, and optical properties measured in the Arabian Peninsula during the DREAME campaign

Polarimetric observations of atmospheric Saharan dust over the Canary Islands have provided strong evidence for the presence of vertically aligned particles. The alignment was thought to be due to the electric field present because of dust charging. It was concluded that the charging and consequent partial alignment could be a common feature of atmospheric mineral dust layers, influencing the optical properties of dust layers and possibly also dust transport (Ulanowski et al. Atmos. Chem. Phys. 7, 6161, 2007). We show preliminary results from the DREAME campaign, aimed at investigating these phenomena. DREAME used simultaneous and collocated measurements from specially developed aerosol radiosondes, and ground-based sun photometers and electric field meters. The radiosondes provided vertical profiles of dust size distribution and electric charge density, in addition to standard meteorological parameters (Ulanowski et al. EGU 2010, AS3.16). The electric field was measured in Kuwait between late April and November 2009, and at Solar Village (Riyadh, Saudi Arabia) between May and June 2009. The measurements were supplemented by satellite retrievals of aerosol properties. Similar measurements but without electric field meters were carried out on Cape Verde Islands in August 2009 (Nicoll et al. EGU 2010, AS4.7). The electric field measured on the ground in Kuwait showed strong variability, particularly in the presence of atmospheric dust, when polarity reversals from the normal positive potential gradient (PG) clear-sky pattern were frequently observed. In the absence of clouds the negative PG excursions were often down to -800 V/m and reached -1300 V/m. The PG was strongly correlated with the aerosol optical thickness (AOT) from the sun photometer: the correlation coefficient was about –0.51 at visible and near infra-red wavelengths and a few percent less in the UV. Slightly lower correlation was present for satellite AOT: -0.4 for MODIS AOT at 550 nm, and -0.3 for OMI AOT at 483.5 nm. On average, the PG decreased by 200 V/m for unit AOT increase. In contrast, the PG measured at Solar Village showed weaker correlation with AOT - about -0.3, with much fewer strong negative PG excursions but some positive ones instead. There were three radiosonde launches in Kuwait, two of which were successful. The size distribution profiles showed dust present mainly in the boundary layer, although on the 1st June a second less dense layer was present between 2.2 and 5.2 km. The dust was accompanied by electric charges with densities up to about 100 pC per cubic metre. However, the charge sensor saturated in the lower, more dense layers, so it is likely that larger values were present. Negative space charge dominated, in agreement with the negative PG found from ground-based measurements. The measured size distributions showed good agreement with AERONET ones and good closure with AOT. Three soundings on Cape Verde Islands (Nicoll et al. EGU 2010, AS4.7) also showed dust predominantly in the boundary layer, and in one sounding dust just above the boundary layer dominated. In all four cases charging was present, with densities typically up to 15 pC per cubic metre. It is concluded that atmospheric mineral dust was generally accompanied by electric charging, and the field may in some cases reach sufficiently high values for dust particle alignment to occur.Peer reviewe

Correlational analysis of challenging behaviours

It is argued that challenging behaviours can be better understood if a correlational analysis (looking for correlations between the occurrence of the behaviour and other variables) is used in addition to functional analysis. A case example is provided of a man whose aggressive outbursts were negatively correlated with trips out of his unit

Development of a specific DNA probe and PCR for the detection of Mycoplasma bovis\ud

Mycoplasma bovis is responsible for several production diseases in cattle, including mastitis, arthritis, pneumonia, abortion and infertility. Current methodologies for detecting and identifying M. bovis are time consuming and difficult. Tests which rely on antigen or antibody detection have poor sensitivity and specificity. In this paper associated protocols for the development of a hybridization probe and PCR are described. A genomic library (SauIIIA digested) was prepared from M. bovis DNA (Colindale Reference Strain: NC10131:02) and cloned into pUC19. Colony hybridization, using a probe preparation made from purified M. bovis DNA, was used to identify colonies of interest. M. bovis DNA fragments were retrieved from recombinant plasmids by digestion with EcoRI and HindIII. This DNA was used to prepare randomly primed probes for dot blot hybridization analysis with immobilized DNA from M. bovis (two strains), M. dispar, M. agalactiae, M. bovigenitalium (two strains), M. ovipneumoniae, a Group 7 strain, M. arginini and bacteria belonging to different genera. Four probes were found to hybridize only with M. bovis and M. ovipneumoniae DNA, whereas one probe reacted with genomic DNA from only one of the two M. bovis strains. The level of sensitivity of the dot blot hybridization assay was 200 CFU (colony forming units)/mL. To enhance the sensitivity further, an M. bovis-specific PCR assay was developed. The primers were designed using sequences obtained from the probe DNA which discriminated M. bovis from all other Mycoplasma DNA tested. The minimum amount of target DNA that could be detected by the PCR assay was that isolated from 10-20 CFU/mL. The PCR assay was therefore 10 times more sensitive than dot blot hybridization

Melioidosis in a rural community of Western Province, Papua New Guinea

A prospective study was conducted to determine the significance of melioidosis in the Balimo district of Western Province, Papua New Guinea. During 1998, after the establishment of laboratory procedures and increasing local clinical awareness, the disease was found in 1.8% (95% CI 0.37–5.1%) of individuals presenting with fever refractory to standard treatment. The clinical incidence was 20.0 per 100 000 population (95% CI 12.2–30.9). The median age of culture-confirmed cases was 9.5 years (interquartile range 8.3–14.8 years). The seroprevalence of 747 community children in the region tested was 8.2% (95% CI 6.2–10.4%). Most individuals presented during the rainy season with a febrile disease refractory to standard treatment, sometimes mimicking tuberculosis. Some family clustering was apparent. All patients with bacteraemic melioidosis died, but treatment with the available conventional therapies of chloramphenicol, co-trimoxazole or doxycycline resulted in survival and cure in six patients with subacute/localised melioidosis. Further studies are needed to ascertain the local epidemiology and why children appear particularly at risk, as well as to establish the true extent of melioidosis in Papua New Guinea

Isolation of Dermatophilus sp from skin lesions in farmed saltwater crocodiles (Crocodylus porosus)

[Extract] The skin is the most valuable product of crocodile farming and any disease affecting it diminishes the quality of the leather and hence its market value. So called brown spot disease, characterised by multiple, small, tan to brown lesions on skin in most body locations, has been recognised by farmers as an important disease problem because affected hides are downgraded.\ud \ud Several reports on crocodilian skin lesions have described the presence of a branching, filamentous organism and on this basis a tentative diagnosis of probable dermatophilosis has been made. Similar lesions have been noted in alligators' and a filamentous organism resembling Dermatophilus was isolated from several animals with brown spot lesions on one farm in Louisiana

Preliminary studies on the prevalence of Mycoplasma bovis mastitis in dairy cattle in Australia

A highly sensitive and specific PCR (MB-PCR) was used in preliminary studies to detect M. bovis in milk samples to investigate its association with high somatic cell count (SCC), an indicator of subclinical mastitis and one of the factors in down grading the quality of milk. A total of 186 and 167 herds were tested with 43% and 62% of herds positive for M. bovis in Victoria and North Queensland, respectively. The quarter milks from 52 cows with persistently high SCC were tested by MB-PCR and culture to investigate the association of M. bovis with major mastitis pathogens (MMP). M. Bovis was detected in 77% of cows of which 19% alone had M. bovis without any other bacteria, 17% had M. bovis in combination with major mastitis pathogens and 40% had M. bovis in combination with non-major mastitis pathogens. We believe that M. bovis is widespread in dairy cattle and has the potential to produce disease alone or to predispose the udder to disease caused by major mastitis and environmental pathogens. These studies have revealed a hitherto unrecognised high prevalence of M. bovis in dairy cattle in North Queensland and Victoria in Australia. These initial studies also give a clear association between M. bovis and elevated somatic cell counts