896 research outputs found
Patterns of past and recent conversion of indigenous grasslands in the South Island, New Zealand
We used recent satellite imagery to quantify the extent, type, and rate of conversion of remaining indigenous grasslands in the inland eastern South Island of New Zealand in recent years. We describe the pattern of conversion in relation to national classifications of land use capability and land environments, and ecological and administrative districts and regions. We show that although large areas of indigenous grasslands remain, grassland loss has been ongoing. Indigenous grassland was reduced in the study area by 3% (70 200 ha) between 1990 and 2008. Almost two-thirds of post-1990 conversion occurred in threatened environments with less than 30% of indigenous cover remaining, primarily in the Waitaki, Mackenzie and Central Otago administrative districts. This conversion occurred primarily on non-arable land. In the Mackenzie and Waitaki districts the rate of conversion in 2001-2008 was approximately twice that in 1990-2001. Opportunities to protect more of the full range of indigenous grasslands lie with the continuing tenure review process in these districts
Operational large-scale segmentation of imagery based on iterative elimination
Image classification and interpretation are greatly aided through the use of image segmentation. Within the field of environmental remote sensing, image segmentation aims to identify regions of unique or dominant ground cover from their attributes such as spectral signature, texture and context. However, many approaches are not scalable for national mapping programmes due to limits in the size of images that can be processed. Therefore, we present a scalable segmentation algorithm, which is seeded using k-means and provides support for a minimum mapping unit through an innovative iterative elimination process. The algorithm has also been demonstrated for the segmentation of time series datasets capturing both the intra-image variation and change regions. The quality of the segmentation results was assessed by comparison with reference segments along with statistics on the inter- and intra-segment spectral variation. The technique is computationally scalable and is being actively used within the national land cover mapping programme for New Zealand. Additionally, 30-m continental mosaics of Landsat and ALOS-PALSAR have been segmented for Australia in support of national forest height and cover mapping. The algorithm has also been made freely available within the open source Remote Sensing and GIS software Library (RSGISLib)
Gambling problems and military- and health-related behaviour in UK Armed Forces veterans
Internationally, problem gambling is elevated in Armed Forces veterans compared to the general population. Here, we re-examined the prevalence of problem gambling in veterans and non-veterans residing in England using an established large dataset and investigated whether gambling was associated with length of service, common mental health disorders, substance abuse, or financial management history. Using the 2007 Adult Psychiatric Morbidity Survey, 257 post-national service veterans and 514 age- and sex-matched controls were compared. Veterans had significantly higher rates of problem gambling than non-veterans. Male veterans were more likely than non-veterans to have experienced a traumatic event. The relationship between veteran status and problem gambling was not explained by differences in mental health conditions, substance abuse, or financial management. No differences were found for length of service. Further research is required with larger samples targeting problem gambling and Armed Forces experience in the United Kingdom population using contemporary diagnostic criteria
Immunogenicity of DTaP-IPV-Hib and MenC vaccines in the UK when administered with a 13-valent pneumococcal conjugate vaccine
Counter Machines and Distributed Automata: A Story about Exchanging Space and Time
We prove the equivalence of two classes of counter machines and one class of
distributed automata. Our counter machines operate on finite words, which they
read from left to right while incrementing or decrementing a fixed number of
counters. The two classes differ in the extra features they offer: one allows
to copy counter values, whereas the other allows to compute copyless sums of
counters. Our distributed automata, on the other hand, operate on directed path
graphs that represent words. All nodes of a path synchronously execute the same
finite-state machine, whose state diagram must be acyclic except for
self-loops, and each node receives as input the state of its direct
predecessor. These devices form a subclass of linear-time one-way cellular
automata.Comment: 15 pages (+ 13 pages of appendices), 5 figures; To appear in the
proceedings of AUTOMATA 2018
Connection between dynamics and thermodynamics of liquids on the melting line
The dynamics of a large number of liquids and polymers exhibit scaling
properties characteristic of a simple repulsive inverse power law (IPL)
potential, most notably the superpositioning of relaxation data as a function
of the variable TV{\gamma}, where T is temperature, V the specific volume, and
{\gamma} a material constant. A related scaling law, TmVm{\Gamma}, with the
same exponent {\Gamma}={\gamma}, links the melting temperature Tm and volume Vm
of the model IPL liquid; liquid dynamics is then invariant at the melting
point. Motivated by a similar invariance of dynamics experimentally observed at
transitions of liquid crystals, we determine dynamic and melting point scaling
exponents {\gamma} and {\Gamma} for a large number of non-associating liquids.
Rigid, spherical molecules containing no polar bonds have {\Gamma}={\gamma};
consequently, the reduced relaxation time, viscosity and diffusion coefficient
are each constant along the melting line. For other liquids {\gamma}>{\Gamma}
always; i.e., the dynamics is more sensitive to volume than is the melting
point, and for these liquids the dynamics at the melting point slows down with
increasing Tm (that is, increasing pressure).Comment: 20 pages, 8 figures, 1 tabl
Climatology of Mid-latitude Ionospheric Disturbances from the Very Large Array Low-frequency Sky Survey
The results of a climatological study of ionospheric disturbances derived
from observations of cosmic sources from the Very Large Array (VLA)
Low-frequency Sky Survey (VLSS) are presented. We have used the ionospheric
corrections applied to the 74 MHz interferometric data within the VLSS imaging
process to obtain fluctuation spectra for the total electron content (TEC)
gradient on spatial scales from a few to hundreds of kilometers and temporal
scales from less than one minute to nearly an hour. The observations sample
nearly all times of day and all seasons. They also span latitudes and
longitudes from 28 deg. N to 40 deg. N and 95 deg. W to 114 deg. W,
respectively. We have binned and averaged the fluctuation spectra according to
time of day, season, and geomagnetic (Kp index) and solar (F10.7) activity.
These spectra provide a detailed, multi-scale account of seasonal and intraday
variations in ionospheric activity with wavelike structures detected at
wavelengths between about 35 and 250 km. In some cases, trends between spectral
power and Kp index and/or F10.7 are also apparent. In addition, the VLSS
observations allow for measurements of the turbulent power spectrum down to
periods of 40 seconds (scales of ~0.4 km at the height of the E-region). While
the level of turbulent activity does not appear to have a strong dependence on
either Kp index or F10.7, it does appear to be more pronounced during the
winter daytime, summer nighttime, and near dusk during the spring.Comment: accepted for publication in Radio Scienc
Precision neutron interferometric measurement of the nd coherent neutron scattering length and consequences for models of three-nucleon forces
We have performed the first high precision measurement of the coherent
neutron scattering length of deuterium in a pure sample using neutron
interferometry. We find b_nd = (6.665 +/- 0.004) fm in agreement with the world
average of previous measurements using different techniques, b_nd = (6.6730 +/-
0.0045) fm. We compare the new world average for the nd coherent scattering
length b_nd = (6.669 +/- 0.003) fm to calculations of the doublet and quartet
scattering lengths from several modern nucleon-nucleon potential models with
three-nucleon force (3NF) additions and show that almost all theories are in
serious disagreement with experiment. This comparison is a more stringent test
of the models than past comparisons with the less precisely-determined nuclear
doublet scattering length of a_nd = (0.65 +/- 0.04) fm.Comment: 4 pages, 4 figure
CloneQC: lightweight sequence verification for synthetic biology
Synthetic biology projects aim to produce physical DNA that matches a designed target sequence. Chemically synthesized oligomers are generally used as the starting point for building larger and larger sequences. Due to the error rate of chemical synthesis, these oligomers can have many differences from the target sequence. As oligomers are joined together to make larger and larger synthetic intermediates, it becomes essential to perform quality control to eliminate intermediates with errors and retain only those DNA molecules that are error free with respect to the target. This step is often performed by transforming bacteria with synthetic DNA and sequencing colonies until a clone with a perfect sequence is identified. Here we present CloneQC, a lightweight software pipeline available as a free web server and as source code that performs quality control on sequenced clones. Input to the server is a list of desired sequences and forward and reverse reads for each clone. The server generates summary statistics (error rates and success rates target-by-target) and a detailed report of perfect clones. This software will be useful to laboratories conducting in-house DNA synthesis and is available at http://cloneqc.thruhere.net/ and as Berkeley Software Distribution (BSD) licensed source
BioPartsBuilder: a synthetic biology tool for combinatorial assembly of biological parts
Abstract
Summary: Combinatorial assembly of DNA elements is an efficient method for building large-scale synthetic pathways from standardized, reusable components. These methods are particularly useful because they enable assembly of multiple DNA fragments in one reaction, at the cost of requiring that each fragment satisfies design constraints. We developed BioPartsBuilder as a biologist-friendly web tool to design biological parts that are compatible with DNA combinatorial assembly methods, such as Golden Gate and related methods. It retrieves biological sequences, enforces compliance with assembly design standards and provides a fabrication plan for each fragment.
Availability and implementation: BioPartsBuilder is accessible at http://public.biopartsbuilder.org and an Amazon Web Services image is available from the AWS Market Place (AMI ID: ami-508acf38). Source code is released under the MIT license, and available for download at https://github.com/baderzone/biopartsbuilder.
Contact: [email protected]
Supplementary information: Supplementary data are available at Bioinformatics online.</jats:p
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