Ground beetle dispersal: how to bridge the scales?

Beneficial arthropods that provide biological control of aphids or weed seeds use a variety of habitats in agricultural landscapes. Information on the movement behaviour of these arthropods between these habitats is needed to develop conservation strategies that sustain pest suppression in agricultural landscapes. Models for movement behaviour may help to understand and explore biocontrol functions. As measurements of behaviour at the landscape scale are technically difficult to make, measurements are often made at smaller scales. It is then necessary to upscale to larger scales, using movement models. Here we present a case study on such upscaling. The first results indicate that upscaling from small scales to large scales, using a correlated random movement model, may result in errors. An alternative approach, to be tested in further work, is to fit the movement model directly to the large scale dat

Discovery of distant high luminosity infrared galaxies

We have developed a method for selecting the most luminous galaxies detected by IRAS based on their extreme values of R, the ratio of 60 micron and B-band luminosity. These objects have optical counterparts that are close to or below the limits of Schmidt surveys. We have tested our method on a 1079 deg^2 region of sky, where we have selected a sample of IRAS sources with 60 micron flux densities greater than 0.2 Jy, corresponding to a redshift limit z~1 for objects with far-IR luminosities of 10^{13} L_sun. Optical identifications for these were obtained from the UK Schmidt Telescope plates, using the likelihood ratio method. Optical spectroscopy has been carried out to reliably identify and measure the redshifts of six objects with very faint optical counterparts, which are the only objects with R>100 in the sample. One object is a hyperluminous infrared galaxy (HyLIG) at z=0.834. Of the remaining, fainter objects, five are ultraluminous infrared galaxies (ULIGs) with a mean redshift of 0.45, higher than the highest known redshift of any non-hyperluminous ULIG prior to this study. High excitation lines reveal the presence of an active nucleus in the HyLIG, just as in the other known infrared-selected HyLIGs. In contrast, no high excitation lines are found in the non-hyperluminous ULIGs. We discuss the implications of our results for the number density of HyLIGs at z<1 and for the evolution of the infrared galaxy population out to this redshift, and show that substantial evolution is indicated. Our selection method is robust against the presence of gravitational lensing if the optical and infrared magnification factors are similar, and we suggest a way of using it to select candidate gravitationally lensed infrared galaxies.Comment: 6 pages, accepted for publication in A&

Magnetic fields at the periphery of UCHII regions from carbon recombination line observations

Several indirect evidences indicate a magnetic origin for the non-thermal width of spectral lines observed toward molecular clouds. In this letter, I suggest that the origin of the non-thermal width of carbon recombination lines (CRLs) observed from photo-dissociation regions (PDRs) near ultra-compact \HII\ regions is magnetic and that the magnitude of the line width is an estimate of the \alfven speed. The magnetic field strengths estimated based on this suggestion compare well with those measured toward molecular clouds with densities similar to PDR densities. I conclude that multi-frequency CRL observations have the potential to form a new tool to determine the field strength near star forming regions.Comment: To appear in ApJ Letter

The Double Quasar Q2138-431: Lensing by a Dark Galaxy?

We report the discovery of a new gravitational lens candidate Q2138-431AB, comprising two quasar images at a redshift of 1.641 separated by 4.5 arcsecs. The spectra of the two images are very similar, and the redshifts agree to better than 115 km.sec$^{-1}$. The two images have magnitudes $B_J = 19.8$ and $B_J = 21.0$, and in spite of a deep search and image subtraction procedure, no lensing galaxy has been found with $R < 23.8$. Modelling of the system configuration implies that the mass-to-light ratio of any lensing galaxy is likely to be around $1000 M_{\odot}/L_{\odot}$, with an absolute lower limit of $200 M_{\odot}/L_{\odot}$ for an Einstein-de Sitter universe. We conclude that the most likely explanation of the observations is gravitational lensing by a dark galaxy, although it is possible we are seeing a binary quasar.Comment: 17 pages (Latex), 8 postscript figures included, accepted by MNRA

Suspended and bedload transport in the surfzone : implications for sand transport models

ACKNOWLEDGMENTS The research presented in this paper is conducted within the SINBAD project, funded by STW (12058) and EPSRC (EP/J00507X/1, EP/J005541/1), and received additional funding through the European Community’s FP7 project Hydralab IV (contract no. 261520).Publisher PD

Unfolding-Based Process Discovery

This paper presents a novel technique for process discovery. In contrast to the current trend, which only considers an event log for discovering a process model, we assume two additional inputs: an independence relation on the set of logged activities, and a collection of negative traces. After deriving an intermediate net unfolding from them, we perform a controlled folding giving rise to a Petri net which contains both the input log and all independence-equivalent traces arising from it. Remarkably, the derived Petri net cannot execute any trace from the negative collection. The entire chain of transformations is fully automated. A tool has been developed and experimental results are provided that witness the significance of the contribution of this paper.Comment: This is the unabridged version of a paper with the same title appearead at the proceedings of ATVA 201

Discovery of distant high luminosity infrared galaxies

We have developed a method for selecting the most luminous galaxies detected by IRAS based on their extreme values of R, the ratio of 60 micron and B-band luminosity. These objects have optical counterparts that are close to or below the limits of Schmidt surveys. We have tested our method on a 1079 deg^2 region of sky, where we have selected a sample of IRAS sources with 60 micron flux densities greater than 0.2 Jy, corresponding to a redshift limit z~1 for objects with far-IR luminosities of 10^{13} L_sun. Optical identifications for these were obtained from the UK Schmidt Telescope plates, using the likelihood ratio method. Optical spectroscopy has been carried out to reliably identify and measure the redshifts of six objects with very faint optical counterparts, which are the only objects with R>100 in the sample. One object is a hyperluminous infrared galaxy (HyLIG) at z=0.834. Of the remaining, fainter objects, five are ultraluminous infrared galaxies (ULIGs) with a mean redshift of 0.45, higher than the highest known redshift of any non-hyperluminous ULIG prior to this study. High excitation lines reveal the presence of an active nucleus in the HyLIG, just as in the other known infrared-selected HyLIGs. In contrast, no high excitation lines are found in the non-hyperluminous ULIGs. We discuss the implications of our results for the number density of HyLIGs at z<1 and for the evolution of the infrared galaxy population out to this redshift, and show that substantial evolution is indicated. Our selection method is robust against the presence of gravitational lensing if the optical and infrared magnification factors are similar, and we suggest a way of using it to select candidate gravitationally lensed infrared galaxies

Time-and-motion tool for the assessment of working time in tuberculosis laboratories: a multicentre study

SETTING: Implementation of novel diagnostic assays in tuberculosis (TB) laboratory diagnosis requires effective management of time and resources. OBJECTIVE: To further develop and assess at multiple centres a time-and-motion (T&M) tool as an objective means for recording the actual time spent on running laboratory assays. DESIGN: Multicentre prospective study conducted in six European Union (EU) reference TB laboratories. RESULTS: A total of 1060 specimens were tested using four laboratory assays. The number of specimens per batch varied from one to 60; a total of 64 recordings were performed. Theoretical hands-on times per specimen (TTPS) in h:min:s for Xpert® MTB/RIF, mycobacterial interspersed repetitive unit-variable number of tandem repeats genotyping, Ziehl-Neelsen staining and manual fluorescence microscopy were respectively 00:33:02 ± 00:12:32, 00:13:34 ± 00:03:11, 00:09:54 ± 00:00:53 and 00:06:23 ± 00:01:36. Variations between laboratories were predominantly linked to the time spent on reporting and administrative procedures. Processing specimens in batches could help save time in highly automated assays (e.g., line-probe) (TTPS 00:14:00 vs. 00:09:45 for batches comprising 7 and 31 specimens, respectively). CONCLUSIONS: The T&M tool can be considered a universal and objective methodology contributing to workload assessment in TB diagnostic laboratories. Comparison of workload between laboratories could help laboratory managers justify their resource and personnel needs for the implementation of novel, time-saving, cost-effective technologies, as well as identify areas for improvement

Adolescent development of psychosis as an outcome of hearing impairment: a 10-year longitudinal study

Background It has long been acknowledged that hearing impairment may increase the risk for psychotic experiences. Recent work suggests that young people in particular may be at risk, indicating a possible developmental mechanism. Method The hypothesis that individuals exposed to hearing impairment in early adolescence would display the highest risk for psychotic symptoms was examined in a prospective cohort study of a population sample of originally 3021 adolescents and young adults aged 14-24 years at baseline, in Munich, Germany (Early Developmental Stages of Psychopathology Study). The expression of psychosis was assessed at multiple time points over a period of up to 10 years, using a diagnostic interview (Munich Composite International Diagnostic Interview; CIDI) administered by clinical psychologists. Results Hearing impairment was associated with CIDI psychotic symptoms [odds ratio (OR) 2.04, 95% confidence interval (CI) 1.10-3.81], particularly more severe psychotic symptoms (OR 5.66, 95% CI 1.64-19.49). The association between hearing impairment and CIDI psychotic symptoms was much stronger in the youngest group aged 14-17 years at baseline (OR 3.28, 95% CI 1.54-7.01) than in the older group aged 18-24 years at baseline (OR 0.82, 95% CI 0.24-2.84). Conclusions The finding of an age-specific association between hearing impairment and psychotic experiences suggests that disruption of development at a critical adolescent phase, in interaction with other personal and social vulnerabilities, may increase the risk for psychotic symptom

NIR Spectroscopy with the VLT of a sample of ISO selected Hubble Deep Field South Galaxies

A new population of faint galaxies characterized by an extremely high rate of evolution with redshift up to z~1.5 has recently been discovered by ISO. These sources are likely to contribute significantly to the cosmic far-IR extragalactic background. We have carried out near-infrared VLT-ISAAC spectroscopy of a sample of ISOCAM galaxies from the Hubble Deep Field South. The rest-frame R-band spectral properties of the ISO population resembles that of powerful dust-enshrouded active starburst galaxies.Comment: 8 pages, 3 figures, to appear in "ISO Surveys of a Dusty Universe", eds. D. Lemke, M. Stickel, K. Wilke, typos correcte