557 research outputs found
ML-SIM: universal reconstruction of structured illumination microscopy images using transfer learning.
Structured illumination microscopy (SIM) has become an important technique for optical super-resolution imaging because it allows a doubling of image resolution at speeds compatible with live-cell imaging. However, the reconstruction of SIM images is often slow, prone to artefacts, and requires multiple parameter adjustments to reflect different hardware or experimental conditions. Here, we introduce a versatile reconstruction method, ML-SIM, which makes use of transfer learning to obtain a parameter-free model that generalises beyond the task of reconstructing data recorded by a specific imaging system for a specific sample type. We demonstrate the generality of the model and the high quality of the obtained reconstructions by application of ML-SIM on raw data obtained for multiple sample types acquired on distinct SIM microscopes. ML-SIM is an end-to-end deep residual neural network that is trained on an auxiliary domain consisting of simulated images, but is transferable to the target task of reconstructing experimental SIM images. By generating the training data to reflect challenging imaging conditions encountered in real systems, ML-SIM becomes robust to noise and irregularities in the illumination patterns of the raw SIM input frames. Since ML-SIM does not require the acquisition of experimental training data, the method can be efficiently adapted to any specific experimental SIM implementation. We compare the reconstruction quality enabled by ML-SIM with current state-of-the-art SIM reconstruction methods and demonstrate advantages in terms of generality and robustness to noise for both simulated and experimental inputs, thus making ML-SIM a useful alternative to traditional methods for challenging imaging conditions. Additionally, reconstruction of a SIM stack is accomplished in less than 200 ms on a modern graphics processing unit, enabling future applications for real-time imaging. Source code and ready-to-use software for the method are available at http://ML-SIM.github.io
STRATEGIC AGRIBUSINESS OPERATION REALIGNMENT IN THE TEXAS PRISON SYSTEM
Mathematical programming-based systems analysis is used to examine the consequences of alternative operation configuration for the agricultural operations within the Texas Department of Criminal Justice. Continuation versus elimination of the total operation as well as individual operating departments are considered. Methodology includes a firm systems operation model combined with capital budgeting and an integer programming based investment model. Results indicate the resources realize a positive return as a whole, but some enterprises are not using resources profitably. The integer investment model is found to be superior for investigating whether to continue multiple interrelated enterprises.agribusiness, enterprise selection, mathematical programming, optimal enterprise organization, Agribusiness,
Low-frequency gravitational-wave science with eLISA/NGO
We review the expected science performance of the New Gravitational-Wave
Observatory (NGO, a.k.a. eLISA), a mission under study by the European Space
Agency for launch in the early 2020s. eLISA will survey the low-frequency
gravitational-wave sky (from 0.1 mHz to 1 Hz), detecting and characterizing a
broad variety of systems and events throughout the Universe, including the
coalescences of massive black holes brought together by galaxy mergers; the
inspirals of stellar-mass black holes and compact stars into central galactic
black holes; several millions of ultracompact binaries, both detached and mass
transferring, in the Galaxy; and possibly unforeseen sources such as the relic
gravitational-wave radiation from the early Universe. eLISA's high
signal-to-noise measurements will provide new insight into the structure and
history of the Universe, and they will test general relativity in its
strong-field dynamical regime.Comment: 20 pages, 8 figures, proceedings of the 9th Amaldi Conference on
Gravitational Waves. Final journal version. For a longer exposition of the
eLISA science case, see http://arxiv.org/abs/1201.362
Comparison of prestellar core elongations and large-scale molecular cloud structures in the Lupus 1 region
Turbulence and magnetic fields are expected to be important for regulating molecular cloud formation and evolution. However, their effects on sub-parsec to 100 parsec scales, leading to the formation of starless cores, are not well understood. We investigate the prestellar core structure morphologies obtained from analysis of the Herschel-SPIRE 350 mum maps of the Lupus I cloud. This distribution is first compared on a statistical basis to the large-scale shape of the main filament. We find the distribution of the elongation position angle of the cores to be consistent with a random distribution, which means no specific orientation of the morphology of the cores is observed with respect to the mean orientation of the large-scale filament in Lupus I, nor relative to a large-scale bent filament model. This distribution is also compared to the mean orientation of the large-scale magnetic fields probed at 350 mum with the Balloon-borne Large Aperture Telescope for Polarimetry during its 2010 campaign. Here again we do not find any correlation between the core morphology distribution and the average orientation of the magnetic fields on parsec scales. Our main conclusion is that the local filament dynamics---including secondary filaments that often run orthogonally to the primary filament---and possibly small-scale variations in the local magnetic field direction, could be the dominant factors for explaining the final orientation of each core
Mechanical design and development of TES bolometer detector arrays for the Advanced ACTPol experiment
The next generation Advanced ACTPol (AdvACT) experiment is currently underway
and will consist of four Transition Edge Sensor (TES) bolometer arrays, with
three operating together, totaling ~5800 detectors on the sky. Building on
experience gained with the ACTPol detector arrays, AdvACT will utilize various
new technologies, including 150mm detector wafers equipped with multichroic
pixels, allowing for a more densely packed focal plane. Each set of detectors
includes a feedhorn array of stacked silicon wafers which form a spline profile
leading to each pixel. This is then followed by a waveguide interface plate,
detector wafer, back short cavity plate, and backshort cap. Each array is
housed in a custom designed structure manufactured from high purity copper and
then gold plated. In addition to the detector array assembly, the array package
also encloses cryogenic readout electronics. We present the full mechanical
design of the AdvACT high frequency (HF) detector array package along with a
detailed look at the detector array stack assemblies. This experiment will also
make use of extensive hardware and software previously developed for ACT, which
will be modified to incorporate the new AdvACT instruments. Therefore, we
discuss the integration of all AdvACT arrays with pre-existing ACTPol
infrastructure.Comment: 9 pages, 5 figures, SPIE Astronomical Telescopes and Instrumentation
conference proceeding
Improving predictive asthma algorithms with modelled environment data for Scotland: an observational cohort study protocol
Introduction Asthma has a considerable, but potentially, avoidable burden on many populations globally. Scotland has some of the poorest health outcomes from asthma. Although ambient pollution, weather changes and sociodemographic factors have been associated with asthma attacks, it remains unclear whether modelled environment data and geospatial information can improve population-based asthma predictive algorithms. We aim to create the afferent loop of a national learning health system for asthma in Scotland. We will investigate the associations between ambient pollution, meteorological, geospatial and sociodemographic factors and asthma attacks.Methods and Analysis We will develop and implement a secured data governance and linkage framework to incorporate primary care health data, modelled environment data, geospatial population and sociodemographic data. Data from 75 recruited primary care practices (n=500â000 patients) in Scotland will be used. Modelled environment data on key air pollutants at a horizontal resolution of 5âkmĂ5âkm at hourly time steps will be generated using the EMEP4UK atmospheric chemistry transport modelling system for the datazones of the primary care practicesâ populations. Scottish population census and education databases will be incorporated into the linkage framework for analysis. We will then undertake a longitudinal retrospective observational analysis. Asthma outcomes include asthma hospitalisations and oral steroid prescriptions. Using a nested caseâcontrol study design, associations between all covariates will be measured using conditional logistic regression to account for the matched design and to identify suitable predictors and potential candidate algorithms for an asthma learning health system in Scotland.Findings from this study will contribute to the development of predictive algorithms for asthma outcomes and be used to form the basis for our learning health system prototype.Ethics and dissemination The study received National Health Service Research Ethics Committee approval (16/SS/0130) and also obtained permissions via the Public Benefit and Privacy Panel for Health and Social Care in Scotland to access, collate and use the following data sets: population and housing census for Scotland; Scottish education data via the Scottish Exchange of Data and primary care data from general practice Data Custodians. Analytic code will be made available in the open source GitHub website. The results of this study will be published in international peer reviewed journals
The balloon-borne large-aperture submillimeter telescope for polarimetry: BLAST-Pol
The Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry
(BLAST-Pol) is a suborbital mapping experiment designed to study the role
played by magnetic fields in the star formation process. BLAST-Pol is the
reconstructed BLAST telescope, with the addition of linear polarization
capability. Using a 1.8 m Cassegrain telescope, BLAST-Pol images the sky onto a
focal plane that consists of 280 bolometric detectors in three arrays,
observing simultaneously at 250, 350, and 500 um. The diffraction-limited
optical system provides a resolution of 30'' at 250 um. The polarimeter
consists of photolithographic polarizing grids mounted in front of each
bolometer/detector array. A rotating 4 K achromatic half-wave plate provides
additional polarization modulation. With its unprecedented mapping speed and
resolution, BLAST-Pol will produce three-color polarization maps for a large
number of molecular clouds. The instrument provides a much needed bridge in
spatial coverage between larger-scale, coarse resolution surveys and narrow
field of view, and high resolution observations of substructure within
molecular cloud cores. The first science flight will be from McMurdo Station,
Antarctica in December 2010.Comment: 14 pages, 9 figures Submitted to SPIE Astronomical Telescopes and
Instrumentation Conference 201
The Case for Dynamic Models of Learners' Ontologies in Physics
In a series of well-known papers, Chi and Slotta (Chi, 1992; Chi & Slotta,
1993; Chi, Slotta & de Leeuw, 1994; Slotta, Chi & Joram, 1995; Chi, 2005;
Slotta & Chi, 2006) have contended that a reason for students' difficulties in
learning physics is that they think about concepts as things rather than as
processes, and that there is a significant barrier between these two
ontological categories. We contest this view, arguing that expert and novice
reasoning often and productively traverses ontological categories. We cite
examples from everyday, classroom, and professional contexts to illustrate
this. We agree with Chi and Slotta that instruction should attend to learners'
ontologies; but we find these ontologies are better understood as dynamic and
context-dependent, rather than as static constraints. To promote one
ontological description in physics instruction, as suggested by Slotta and Chi,
could undermine novices' access to productive cognitive resources they bring to
their studies and inhibit their transition to the dynamic ontological
flexibility required of experts.Comment: The Journal of the Learning Sciences (In Press
Molecular phylogeny of IndoâPacific carpenter ants (Hymenoptera: Formicidae, Camponotus) reveals waves of dispersal and colonization from diverse source areas
Ants that resemble Camponotus maculatus (Fabricius, 1782) present an opportunity to test the hypothesis that the origin of the Pacific island fauna was primarily New Guinea, the Philippines, and the IndoâMalay archipelago (collectively known as Malesia). We sequenced two mitochondrial and four nuclear markers from 146 specimens from Pacific islands, Australia, and Malesia. We also added 211 specimens representing a larger worldwide sample and performed a series of phylogenetic analyses and ancestral area reconstructions. Results indicate that the Pacific members of this group comprise several robust clades that have distinctly different biogeographical histories, and they suggest an important role for Australia as a source of Pacific colonizations. Malesian areas were recovered mostly in derived positions, and one lineage appears to be Neotropical. Phylogenetic hypotheses indicate that the orange, panâPacific form commonly identified as C. chloroticus Emery 1897 actually consists of two distantly related lineages. Also, the lineage on HawaiÊ»i, which has been called C. variegatus (Smith, 1858), appears to be closely related to C. tortuganus Emery, 1895 in Florida and other lineages in the New World. In Micronesia and Polynesia the C. chloroticusâlike species support predictions of the taxonâcycle hypothesis and could be candidates for humanâmediated dispersal.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/1/cla12099-sup-0002-FigureS2.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/2/cla12099-sup-0003-FigureS3.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/3/cla12099-sup-0001-FigureS1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/4/cla12099-sup-0004-FigureS4.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/5/cla12099-sup-0005-FigureS5.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/6/cla12099-sup-0006-FigureS6.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112260/7/cla12099.pd
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