642 research outputs found
The London Basin superficial and bedrock LithoFrame 50 Model
This report describes the methodology and datasets used in the construction of the 1:50 000
resolution superficial and bedrock geological model of the London Basin.
The London Basin study area was divided into twelve 20 x 20 km tiles, with construction of the
first tiles beginning in 2006 and completion of the combined model in 2014. This time period
coincided with the ongoing development of GSI3D software which was used to construct much
of the model. The GSI3D software was used to calculate a rockhead (base Quaternary and
Anthropocene) surface that was then used as a capping surface for the modelling of the bedrock
geology in the GOCAD® software.
The model complements the corresponding DiGMapGB-50 tiles of the area and consists of about
80 modelled geological units, comprising mass movement (landslip), artificial, superficial, and
bedrock.
This report supersedes an earlier report detailing the construction of the superficial part of this
model (Burke et al. 2013).
A glossary of technical terms used is included at the end of this report
A geological model of London and the Thames Valley, southeast England
Many geological survey organisations have started delivering digital geological models as part of their role. This article describes the British Geological Survey (BGS) model for London and the Thames Valley in southeast England. The model covers 4800 km2 and extends to several hundred metres depth. It includes extensive spreads of Quaternary river terraces and alluvium of the Thames drainage system resting on faulted and folded Palaeogene and Cretaceous bedrock strata. The model extends to the base of the Jurassic sedimentary rocks.
The baseline datasets used and the uses and limitations of the model are given. The model has been used to generate grids for the elevation of the base of the Quaternary, the thickness of Quaternary deposits, and enabled a reassessment of the subcrop distribution and faulting of the Palaeogene and Cretaceous bedrock units especially beneath the Quaternary deposits.
Digital outputs from the model include representations of geological surfaces, which can be used in GIS, CAD and geological modelling software, and also graphic depictions such as a fence diagram of cross-sections through the model. The model can be viewed as a whole, and be dissected, in the BGS Lithoframe Viewer. Spatial queries of this and other BGS models, at specific points, along defined lines or at a specified depth, can be performed with the new BGS Groundhog application, which delivers template-based reports.
The model should be viewed as a first version that should be improved further, and kept up to date, as new data and understanding emerges
Sexual and social stimuli elicit rapid and contrasting genomic responses
Sensory physiology has been shown to influence female mate choice, yet little is known about the mechanisms within the brain that regulate this critical behaviour. Here we examine preference behaviour of 58 female swordtails, Xiphophorus nigrensis, in four different social environments (attractive and unattractive males, females only, non-attractive males only and asocial conditions) followed by neural gene expression profiling. We used a brain-specific cDNA microarray to identify patterns of genomic response and candidate genes, followed by quantitative PCR (qPCR) examination of gene expression with variation in behaviour. Our microarray results revealed patterns of genomic response differing more between classes of social stimuli than between presence versus absence of stimuli. We identified suites of genes showing diametrically opposed patterns of expression: genes that are turned ‘on’ while females interact with attractive males are turned ‘off’ when interacting with other females, and vice versa. Our qPCR results identified significant predictive relationships between five candidate genes and specific mate choice behaviours (preference and receptivity) across females exposed to males, with no significant patterns identified in female or asocial conditions or with overall locomotor activity. The identification of stimulus- and behaviour-specific responses opens an exciting window into the molecular pathways associated with social behaviour and mechanisms that underlie sexual selection
Identifying the mechanisms underpinning recognition of structured sequences of action
© 2012 The Experimental Psychology SocietyWe present three experiments to identify the specific information sources that skilled participants use to make recognition judgements when presented with dynamic, structured stimuli. A group of less skilled
participants acted as controls. In all experiments, participants were presented with filmed stimuli containing structured action sequences. In a subsequent recognition phase, participants were presented with new and previously seen stimuli and were required to make judgements as to whether or not each sequence had been presented earlier (or were edited versions of earlier sequences). In Experiment 1,
skilled participants demonstrated superior sensitivity in recognition when viewing dynamic clips compared with static images and clips where the frames were presented in a nonsequential, randomized manner, implicating the importance of motion information when identifying familiar or unfamiliar sequences. In Experiment 2, we presented normal and mirror-reversed sequences in order to distort access to absolute motion information. Skilled participants demonstrated superior recognition sensitivity, but no significant differences were observed across viewing conditions, leading to the suggestion
that skilled participants are more likely to extract relative rather than absolute motion when making such judgements. In Experiment 3, we manipulated relative motion information by occluding several display
features for the duration of each film sequence. A significant decrement in performance was reported when centrally located features were occluded compared to those located in more peripheral positions.
Findings indicate that skilled participants are particularly sensitive to relative motion information when attempting to identify familiarity in dynamic, visual displays involving interaction between numerous features
On The Low Frequency Quasi Periodic Oscillations of X-ray Sources
Based on the interpretation of the twin kilohertz Quasi Periodic Oscillations
(kHz QPOs) of X-ray spectra of Low Mass X-Ray Binaries
(LMXBs) to the Keplerian and the periastron precession frequencies at the
magnetosphere-disk of X-ray neutron star (NS) respectively, we ascribe the low
frequency Quasi Periodic Oscillations (LFQPO) and HBO (15-60 Hz QPO for Z
sources or Atoll sources) to the periastron precession at some outer disk
radius.
The obtained conclusions include: all QPO frequencies increase with
increasing the accretion rate. The obtained theoretical relations between HBO
(LFQPO) frequency and the kHz QPO frequency are similar to the measured
empirical formula. Further, the possible dynamical mechanism for QPO production
is discussed.Comment: 6 pages, 2 figures, accepted by APSS, 200
Piolhos hematófagos podem disseminar infecção pelo Trypanosoma cruzi em babuínos
Trypanosoma cruzi (Schyzotrypanum, Chagas, 1909), and Chagas disease are endemic in captive-reared baboons at the Southwest Foundation for Biomedical Research, San Antonio, Texas. We obtained PCR amplification products from DNA extracted from sucking lice collected from the hair and skin of T. cruzi-infected baboons, with specific nested sets of primers for the protozoan kinetoplast DNA, and nuclear DNA. These products were hybridized to their complementary internal sequences. Selected sequences were cloned and sequencing established the presence of T. cruzi nuclear DNA, and minicircle kDNA. Competitive PCR with a kDNA set of primers determined the quantity of approximately 23.9 ± 18.2 T. cruzi per louse. This finding suggests that the louse may be a vector incidentally contributing to the dissemination of T. cruzi infection in the baboon colony.As infecções pelo Trypanosoma cruzi e a doença de Chagas são endêmicas em babuínos (Papio hamadryas) reproduzidos em cativeiro na Southwest Foundation for Biomedical Research, em Santo Antonio, Texas. Nós obtivemos produtos de amplificação por PCR do DNA extraído de piolhos colhidos do cabelo e da pele de babuínos chagásicos, com primers aneladores específicos para DNAs nuclear e de cinetoplasto do protozoário. Esses produtos foram hibridizados com suas respectivas seqüências internas complementares. Seqüências selecionadas foram clonadas e o sequenciamento demonstrou a presença de DNA nuclear de T. cruzi, e de minicírculo de kDNA. A PCR competitiva com primers de kDNA determinou a quantidade de aproximadamente 23.9 ± 18.2 T. cruzi por piolho. Este achado sugere que o piolho pode ser um vetor contribuindo para a disseminação de T. cruzi na colônia de babuínos
High sensitivity measurement of 224Ra and 226Ra in water with an improved hydrous titanium oxide technique at the Sudbury Neutrino Observatory
The existing hydrous titanium oxide (HTiO) technique for the measurement of
224Ra and 226Ra in the water at the Sudbury Neutrino Observatory (SNO) has been
changed to make it faster and less sensitive to trace impurities in the HTiO
eluate. Using HTiO-loaded filters followed by cation exchange adsorption and
HTiO co-precipitation, Ra isotopes from 200-450 tonnes of heavy water can be
extracted and concentrated into a single sample of a few millilitres with a
total chemical efficiency of 50%. Combined with beta-alpha coincidence
counting, this method is capable of measuring 2.0x10^3 uBq/kg of 224Ra and
3.7x10^3 uBq/kg of 226Ra from the 232Th and 238U decay chains, respectively,
for a 275 tonne D2O assay, which are equivalent to 5x10^16 g Th/g and 3x10^16 g
U/g in heavy water.Comment: 8 Pages, 2 figures and 2 table
Вивчення процесу синтезу нанокристалічних плівок двооксиду титану в розряді магнетронного типу за його оптичними та плазмодинамічними характеристиками
Наведено результати експериментального дослiдження плазмодинамiчних i оптичних характеристик цилiндричного газового розряду магнетронного типу в умовах безперервного контролю спектра, випромiнюваного плазмою в дiапазонi 350–820 нм. Визначено умови для синтезу бiнарної сполуки TiО₂, якi забезпечуються пiдтримкою величини iнтенсивностi спектральних лiнiй реагуючих компонентiв i плазмоутворюючого газу. Розглянуто можливiсть контролю умов одержання плiвок TiО₂ як по спектральних характеристиках плазми розряду, так i по змiнi розрядної напруги. Елiпсометричнi дослiдження нанокристалiчних плiвок двооксиду титану показали наявнiсть залежностi показника переломлення вiд товщини плiвки.We present the results of experimental researches of plasmodynamic and optical characteristics of a magnetron-type cylindrical gas discharge. The study was carried out provided a permanent monitoring of the spectrum emitted by plasma in the range 350–820 nm. For the synthesis of binary compound TiO₂, we have determined conditions which can be ensured by a support of the intensity of spectral lines emitted by reacting components and plasma-forming gas. A possibility to control the conditions of the fabrication of a TiO₂ film with the use of both the spectral characteristics of a discharge plasma and a variation of the discharge voltage has been analyzed. Ellipsometric and spectral studies of nanocrystalline titanium dioxide films revealed the dependence of the refractive index of a film on the film thickness.Приведены результаты экспериментального исследования плазмодинамических и оптических характеристик цилиндрического газового разряда магнетронного типа в условиях непрерывного контроля спектра, излучаемого плазмой в диапазоне 350–820 нм. Определены условия для синтеза бинарного соединения TiО₂, которые обеспечиваются поддержанием величины интенсивности спектральных линий реагирующих компонент и плазмообразующего газа. Рассмотрена возможность контроля условий получения пленок TiO₂ как по спектральным характеристикам плазмы разряда, так и по изменению разрядного напряжения. Эллипсометрические и спектральные исследования нанокристаллических пленок диоксида титана показали наличие зависимости показателя преломления от толщины пленки
Generalized quantum Fokker-Planck, diffusion and Smoluchowski equations with true probability distribution functions
Traditionally, the quantum Brownian motion is described by Fokker-Planck or
diffusion equations in terms of quasi-probability distribution functions, e.g.,
Wigner functions. These often become singular or negative in the full quantum
regime. In this paper a simple approach to non-Markovian theory of quantum
Brownian motion using {\it true probability distribution functions} is
presented. Based on an initial coherent state representation of the bath
oscillators and an equilibrium canonical distribution of the quantum mechanical
mean values of their co-ordinates and momenta we derive a generalized quantum
Langevin equation in -numbers and show that the latter is amenable to a
theoretical analysis in terms of the classical theory of non-Markovian
dynamics. The corresponding Fokker-Planck, diffusion and the Smoluchowski
equations are the {\it exact} quantum analogues of their classical
counterparts. The present work is {\it independent} of path integral
techniques. The theory as developed here is a natural extension of its
classical version and is valid for arbitrary temperature and friction
(Smoluchowski equation being considered in the overdamped limit).Comment: RevTex, 16 pages, 7 figures, To appear in Physical Review E (minor
revision
GDGMV Borehole Database Interface User Guide
This report is the published product of a collaboration between the British Geological Survey (BGS) and the General Department of Geology and Minerals Vietnam (GDGMV) and Ministry of Natural Resources and Environment (MONRE) as part of the Hanoi Urban Geology Project. The project has been ongoing since 2016, funded through the by BGS NC-ODA: Geoscience for Sustainable Futures Programme. The project delivers against three priority themes:
1) Development of Digital Systems and Workflows
2) Urban Geology for Planning Policy and Construction
3) Training, Knowledge Exchange and Stakeholder Engagement
These tasks are delivering new digital data technology, new working practices, and increased institutional capacity with respect to urban geoscience.
The GDGMV Borehole Database Interface outlined in this document is one of many systems developed and put in place. This report should be used in conjunction with the other reports related to this collaboration, including:
OR/21/019 – GDGMV Lexicon Database User Guide
OR/20/55 – Considerations for Borehole Coding and Coded Borehole Data Checking
There is also a toolbox of documents, data tools, and workflows available
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