1,467 research outputs found
The spectroscopic detection of drugs of abuse in fingerprints after development with powders and recovery with adhesive lifters
The application of powders to fingerprints has long been established as an effective and reliable method
for developing latent fingerprints. Fingerprints developed in situ at a crime scene routinely undergo lifting
with specialist tapes and are then stored in evidence bags to allow secure transit and also to preserve the
chain of evidence. In a previous study we have shown that exogenous material within a fingerprint can
be detected using Raman spectroscopy following development with powders and lifting with adhesive
tapes. Other reports have detailed the use of Raman spectroscopy to the detection of drugs of abuse
in latent fingerprints including cyanoacrylate-fumed fingerprints. This study involves the application of
Raman spectroscopy for the analysis of drugs of abuse in latent fingerprints for fingerprints that had
been treated with powders and also subsequently lifted with adhesive tapes. Samples of seized ecstasy,
cocaine, ketamine and amphetamine were supplied by East Sussex Police and by the TICTAC unit at St.
Georges Hospital Tooting. Contaminated fingerprintswere deposited on clean glass slides. The application
of aluminium or iron based powders to contaminated fingerprints did not interfere with theRamanspectra
obtained for the contaminants. Contaminated fingerprints developed with powders and then lifted with
lifting tapes were also examined. The combination of these two techniques did not interfere with the
successful analysis. The lifting processwas repeated using hinge lifters. As the hinge lifters exhibited strong
Raman bands the spectroscopic analysiswas more complex and an increase in the number of exposures to
the detector allowed for improved clarification. Spectral subtraction was performed to remove peaks due
to the hinge lifters using OMNIC software. Raman spectra of developed and lifted fingerprints recorded
through evidence bags were obtained and it was found that the detection process was not compromised.
Although the application of powders did not interfere with the detection process the time taken to locate
the contaminant was increased due to the physical presence of more material within the fingerprint
Millimeter wave transmission spectroscopy of gated two-dimensional hole systems
We developed a differential transmission to study cyclotron resonance of GaAs/AlxGa1 xAs
two-dimensional hole samples. The technique utilizes a modulated AuPd gate isolated by a Si3N4
dielectric from the sample, which is irradiated opposite the gate by millimeter waves ranging from
2 to 40GHz. This technique effectively removes the background signal and yields a hole effective
mass of 0:41me with a cyclotron scattering time of 20 ps, consistent with the previous results using
different techniques
The response of soil microbial diversity and abundance to long-term application of biosolids
The disposal of biosolids poses a major environmental and economic problem. Agricultural use is generally regarded as the best means of disposal. However, its impact on soil ecosystems remains uncertain. Biosolids can improve soil properties by supplying nutrients and increasing organic matter content but there is also a potentially detrimental effect arising from the introduction of heavy metals into soils. To assess the balance between these competing effects on soil health, we investigated soil bacterial and fungal diversity and community structure at a site that has been dedicated to the disposal of sewage sludge for over 100 years. Terminal restriction fragment length polymorphism (T-RFLP) was used to characterize the soil microbial communities. The most important contaminants at the site were Ni, Cu, Zn, Cd, and Pb. Concentrations were highly correlated and Zn concentration was adopted as a good indicator of the overall (historical) biosolids loading. A biosolids loading, equivalent to 700â1000 mg kgâ1 Zn appeared to be optimal for maximum bacterial and fungal diversity. This markedly exceeds the maximum soil Zn concentration of 300 mg kgâ1permitted under the current UK Sludge (use in agriculture) Regulations. Redundancy analysis (RDA) suggested that the soil microbial communities had been altered in response to the accumulation of trace metals, especially Zn, Cd, and Cu. We believe this is the first time the trade-off between positive and negative effects of long term (>100 years) biosolids disposal on soil microorganisms have been observed in the field situation
Queen Dominance May Reduce Worker Mushroom Body Size in a Social Bee
The mushroom body (MB) is an area of the insect brain involved in learning, memory, and sensory integration. Here, we used the sweat bee Megalopta genalis (Halictidae) to test for differences between queens and workers in the volume of the MB calyces. We used confocal microscopy to measure the volume of the whole brain, MB calyces, optic lobes, and antennal lobes of queens and workers. Queens had larger brains, larger MB calyces, and a larger MB calyces:whole brain ratio than workers, suggesting an effect of social dominance in brain development. This could result from social interactions leading to smaller worker MBs, or larger queen MBs. It could also result from other factors, such as differences in age or sensory experience. To test these explanations, we next compared queens and workers to other groups. We compared newly emerged bees, bees reared in isolation for 10Â days, bees initiating new observation nests, and bees initiating new natural nests collected from the field to queens and workers. Queens did not differ from these other groups. We suggest that the effects of queen dominance over workers, rather than differences in age, experience, or reproductive status, are responsible for the queenâworker differences we observed. Worker MB development may be affected by queen aggression directly and/or manipulation of larval nutrition, which is provisioned by the queen. We found no consistent differences in the size of antennal lobes or optic lobes associated with differences in age, experience, reproductive status, or social caste.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/150573/1/dneu22705_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/150573/2/dneu22705.pd
Arable crop disease control, climate change and food security
Copyright Association of Applied BiologistsGlobal food security is threatened by crop diseases that account for average yield losses of 16%. Climate change is exacerbating threats to food security in much of the world, emphasising the need to increase food production in northern European countries such as the UK. However, to mitigate climate change, crops must be grown so as to minimise greenhouse gas emissions (GHG); results with UK oilseed rape demonstrate how disease control in arable crops can contribute to climate change mitigation. However, work examining impacts of climate change on UK epidemics of winter oilseed rape diseases illustrates unexpected, contrasting impacts of climate change on complex plant-disease interactions. In England, phoma stem canker is expected to become more severe whilst light leaf spot is expected to become less severe. Such work can provide guidance for government and industry planning for adaptation to impacts of climate change on crops to ensure future food securityFinal Accepted Versio
A renormalization group invariant scalar glueball operator in the (Refined) Gribov-Zwanziger framework
This paper presents a complete algebraic analysis of the renormalizability of
the operator in the Gribov-Zwanziger (GZ) formalism as
well as in the Refined Gribov-Zwanziger (RGZ) version. The GZ formalism offers
a way to deal with gauge copies in the Landau gauge. We explicitly show that
mixes with other gauge variant operators, and we determine
the mixing matrix to all orders, thereby only using algebraic arguments.
The mixing matrix allows us to uncover a renormalization group invariant
including the operator . With this renormalization group
invariant, we have paved the way for the study of the lightest scalar glueball
in the GZ formalism. We discuss how the soft breaking of the BRST symmetry of
the GZ action can influence the glueball correlation function. We expect
non-trivial mass scales, inherent to the GZ approach, to enter the pole
structure of this correlation function.Comment: 27 page
The holonomy of the supercovariant connection and Killing spinors
We show that the holonomy of the supercovariant connection for M-theory
backgrounds with Killing spinors reduces to a subgroup of SL(32-N,\bR)\st
(\oplus^N \bR^{32-N}). We use this to give the necessary and sufficient
conditions for a background to admit Killing spinors. We show that there is
no topological obstruction for the existence of up to 22 Killing spinors in
eleven-dimensional spacetime. We investigate the symmetry superalgebras of
supersymmetric backgrounds and find that their structure constants are
determined by an antisymmetric matrix. The Lie subalgebra of bosonic generators
is related to a real form of a symplectic group. We show that there is a
one-one correspondence between certain bases of the Cartan subalgebra of
sl(32, \bR) and supersymmetric planar probe M-brane configurations. A
supersymmetric probe configuration can involve up to 31 linearly independent
planar branes and preserves one supersymmetry. The space of supersymmetric
planar probe M-brane configurations is preserved by an SO(32,\bR) subgroup of
SL(32, \bR).Comment: 27 pages, a key reference was added. v3: minor change
Magnetic field diagnostics and spatio-temporal variability of the solar transition region
Magnetic field diagnostics of the transition region from the chromosphere to
the corona faces us with the problem that one has to apply extreme UV
spectro-polarimetry. While for coronal diagnostic techniques already exist
through infrared coronagraphy above the limb and radio observations on the
disk, for the transition region one has to investigate extreme UV observations.
However, so far the success of such observations has been limited, but there
are various projects to get spectro-polarimetric data in the extreme UV in the
near future. Therefore it is timely to study the polarimetric signals we can
expect for such observations through realistic forward modeling.
We employ a 3D MHD forward model of the solar corona and synthesize the
Stokes I and Stokes V profiles of C IV 1548 A. A signal well above 0.001 in
Stokes V can be expected, even when integrating for several minutes in order to
reach the required signal-to-noise ratio, despite the fact that the intensity
in the model is rapidly changing (just as in observations). Often this
variability of the intensity is used as an argument against transition region
magnetic diagnostics which requires exposure times of minutes. However, the
magnetic field is evolving much slower than the intensity, and thus when
integrating in time the degree of (circular) polarization remains rather
constant. Our study shows the feasibility to measure the transition region
magnetic field, if a polarimetric accuracy on the order of 0.001 can be
reached, which we can expect from planned instrumentation.Comment: Accepted for publication in Solar Physics (4.Mar.2013), 19 pages, 9
figure
Language and reading development in children learning English as an additional language in primary school in England
Children learning English as an additional language (EAL) are a growing population of learners in English primary schools. These children begin school with differing levels of English language proficiency and tend to underperform in relation to their nonâEAL peers on measures of English oral language and reading. However, little work has examined the developmental trajectories of these skills in EAL learners in England. EAL learners and 33 nonâEAL peers in Year 4 (age 8â9 years) were assessed at three time points over 18 months on measures of oral language (vocabulary, grammar and listening comprehension), phonological processing (spoonerisms and rapid automatised naming) and reading skills (singleâword decoding and passage reading). At t1, EAL learners scored significantly lower than nonâEAL peers in receptive and expressive vocabulary (breadth but not depth), spoonerisms and passage reading accuracy. Contrary to previous research, no significant group differences were found in listening or reading comprehension skills. With the exception of passage reading accuracy, there was no evidence for convergence or divergence between the groups in rate of progress over time. After three years of Englishâmedium classroom instruction, EAL learners continue to underperform relative to their nonâEAL peers in breadth of English vocabulary knowledge. This discrepancy in vocabulary knowledge does not appear to narrow as a result of regular classroom instruction in the run up to the final stages of primary school, pinpointing vocabulary as a key target for intervention
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