41,203 research outputs found
Comment on "Under-reported data analysis with INAR-hidden Markov chains"
In Fernandez-Fontelo et al (Statis. Med. 2016, DOI 10.1002/sim.7026) hidden
integer-valued autoregressive (INAR) processes are used to estimate reporting
probabilities for various diseases. In this comment it is demonstrated that the
Poisson INAR(1) model with time-homogeneous underreporting can be expressed
equivalently as a completely observed INAR(inf) model with a geometric lag
structure. This implies that estimated reporting probabilities depend on the
assumed lag structure of the latent process.Comment: This is the pre-reviewing version of a letter published in Statistics
in Medicine 38(5), 893-898:
https://onlinelibrary.wiley.com/doi/full/10.1002/sim.8032 Fernandez-Fontelo
et al published a reply which raises some interesting further points:
https://onlinelibrary.wiley.com/doi/10.1002/sim.8033 After a 12 month embargo
period the accepted version will be made available on arxi
First-principles study of ferroelectricity and pressure-induced phase transitions in HgTiO
Ground-state structure is found and pressure-induced phase transitions up to
210 kbar are studied in mercury titanate from first principles within the
density functional theory. It is established that the structure
experimentally observed in HgTiO is metastable at ambient pressure. With
increasing the hydrostatic pressure, the ground-state structure changes
following the sequence. It is shown that the
appearance of ferroelectricity in HgTiO at is associated with an
unstable phonon mode. Optical and elastic properties of different phases of
mercury titanate are calculated. The quasiparticle band gap calculated in the
\emph{GW} approximation ( eV) agrees with experimental data better
than the value obtained in the LDA approximation (1.49 eV). Analysis of the
thermodynamic stability explains why the synthesis of mercury titanate is
possible only at high pressures.Comment: 8 pages, 4 figures, 5 tables; to appear in Phase Transition
The Glasgow sustainable urban drainage system management project: Case studies (Belvidere hospital and Celtic FC stadium areas)
The Glasgow Sustainable Urban Drainage System (SUDS) Management Project satisfies the first phase
of the Glasgow Surface Water Management Project. This is Glasgow City Council’s contribution to the
Transformation of Rural and Urban Spatial Structure (TRUST) project, one of the European Union’s (EU)
interregional (INTERREG IIIB) funded research projects. The remit of this EU project comprises also
other representative regions in Europe. The project shows also how SUDS can contribute to the overall
catchment dynamics of cities such as Glasgow, ultimately relieving stress on the current predominantly
combined sewer system. Fifty-seven sites within 46 areas of Glasgow were identified for investigation. A
detailed soil chemistry analysis, a preliminary SUDS feasibility assessment and a desk study relating to
historical planning issues that may be relevant for subsequent future development and regeneration options
were undertaken. Detailed design and management guidelines were then drafted for selected representative
demonstration areas (Belvidere Hospital and Celtic FC Stadium Areas) of high public and property
developers interest, and education value. A combination of infiltration trenches or swales with ponds
or underground storage were the most likely SUDS options for the majority of the demonstration areas.
Soil contamination issues were considered when selecting SUDS because heavy metals such as lead and
zinc can cause environmental health problems
Nanocrystalline semiconductors: synthesis, properties, and perspectives
The preparation of hollow particles of ZnO by calcination of hydrozincite coated poly(styrene)
beads is reported. Synthetic studies have been performed on such polymer/inorganic composite
precursors in order to establish the optimum conditions for the preparation of the ZnO particles. The
morphological properties of the powders were characterised by optical microscopy and scanning
electron microscopy. The micrometric ZnO particles show morphological characteristics related to the
template used in their preparation
The Glasgow sustainable urban drainage system management project: Case studies (Belvidere hospital and Celtic FC stadium areas)
The Glasgow Sustainable Urban Drainage System (SUDS) Management Project satisfies the first phase
of the Glasgow Surface Water Management Project. This is Glasgow City Council’s contribution to the
Transformation of Rural and Urban Spatial Structure (TRUST) project, one of the European Union’s (EU)
interregional (INTERREG IIIB) funded research projects. The remit of this EU project comprises also
other representative regions in Europe. The project shows also how SUDS can contribute to the overall
catchment dynamics of cities such as Glasgow, ultimately relieving stress on the current predominantly
combined sewer system. Fifty-seven sites within 46 areas of Glasgow were identified for investigation. A
detailed soil chemistry analysis, a preliminary SUDS feasibility assessment and a desk study relating to
historical planning issues that may be relevant for subsequent future development and regeneration options
were undertaken. Detailed design and management guidelines were then drafted for selected representative
demonstration areas (Belvidere Hospital and Celtic FC Stadium Areas) of high public and property
developers interest, and education value. A combination of infiltration trenches or swales with ponds
or underground storage were the most likely SUDS options for the majority of the demonstration areas.
Soil contamination issues were considered when selecting SUDS because heavy metals such as lead and
zinc can cause environmental health problems
Recommended from our members
Concomitant induction of the cell surface expression of Ia determinants and accessory cell function by a murine macrophage tumor cell line.
This study demonstrates that an uncharacterized soluble factor produced in concanavalin A-induced rat spleen cell suspensions has the capacity to induce the increased expression of cell surface H-2K and H-2D molecules and the expression of I-region gene products on murine monocyte-macrophage lineage tumors that are not Ia positive in the absence of the factor. In parallel with induction of serologically defined Ia specificities, Ia-induced WEHI-3 macrophage tumor cells are capable of providing accessory cell function in stimulating IL-2 production by T-T hybridomas that are activated in a major histocompatibility complex-restricted, antigen-dependent fashion. The uninduced Ia-negative WEHI-3 tumor cells do not trigger a comparable response in this assay system
Vaults. III. Vault ribonucleoprotein particles open into flower-like structures with octagonal symmetry.
The structure of rat liver vault ribonucleoprotein particles was examined using several different staining techniques in conjunction with EM and digestion with hydrolytic enzymes. Quantitative scanning transmission EM demonstrates that each vault particle has a total mass of 12.9 +/- 1 MD and contains two centers of mass, suggesting that each vault particle is a dimer. Freeze-etch reveals that each vault opens into delicate flower-like structures, in which eight rectangular petals are joined to a central ring, each by a thin hook. Vaults examined by negative stain and conventional transmission EM (CTEM) also reveal the flower-like structure. Trypsin treatment of vaults resulted exclusively in cleavage of the major vault protein (p104) and concurrently alters their structure as revealed by negative stain/CTEM, consistent with a localization of p104 to the flower petals. We propose a structural model that predicts the stoichiometry of vault proteins and RNA, defines vault dimer-monomer interactions, and describes two possible modes for unfolding of vaults into flowers. These highly dynamic structural variations are likely to play a role in vault function
Recommended from our members
Subpopulations of liver coated vesicles resolved by preparative agarose gel electrophoresis.
Rat liver clathrin coated vesicles (CVs) were separated into several distinct subpopulations using non-sieving concentrations of agarose, which allowed the separation of species differing primarily in surface charge. Using preparative agarose electrophoresis (Kedersha, N. L., and L. H. Rome, 1986, Anal. Biochem., in press), the CVs were recovered and analyzed for differences in morphology, coat protein composition, and stripped vesicle protein composition. Coat proteins from different populations appeared identical on SDS PAGE, and triskelions stripped from the different populations showed the same mobility on the agarose gel, suggesting that the mobility differences observed in intact CVs were due to differences in the surface charge of underlying vesicles rather than to variations in their clathrin coats. Several non-coat polypeptides appeared to segregate exclusively with different populations as resolved by two-dimensional electrophoresis. Stripped CVs also exhibited considerable heterogeneity when analyzed by Western blotting: the fast-migrating population was enriched in the mannose 6-phosphate receptor, secretory acetylcholine esterase, and an Mr 195,000 glycoprotein. The slow-migrating population of CVs was enriched in the asialoglycoprotein receptor, and it appeared to contain all detectable concanavalin A-binding polypeptides as well as the bulk of detectable WGA-binding proteins. When CVs were prepared from 125I-asialoorosomucoid-perfused rat liver, ligand was found in the slow-migrating CVs, suggesting that these were endocytic in origin. Morphological differences were also observed: the fast-migrating population was enriched in smaller CVs, whereas the slow-migrating population exhibited an enrichment in larger CVs. As liver consists largely of hepatocytes, these subpopulations appear to originate from the same cell type and probably represent CVs of different intracellular origin and destination
A failed invasion? Commercially introduced pollinators in Southern France
The natural diversity of Bombus terrestris subspecies could be under
threat from the commercialisation of bumblebees. Therefore, to determine whether
commercially imported bumblebees are able to establish and spread, we carried out
long-term observations of bumblebees in southern France. Our surveys occurred before,
during, and after the importation (between 1989 and 1996) of thousands of colonies of the
Sardinian subspecies B. t. sassaricus. Queens and males of B. t.
sassaricus were observed foraging outside commercial greenhouses in 1991, 1993,
and 1994 and feral workers were observed foraging on native vegetation nearly two years
after the importation of B. t. sassaricus ceased. However, no B.
t. sassaricus, or F1 hybrids were observed after 1998. We conclude that
B. t. sassaricus remains inconspicuous in France and competition from
the three native subspecies may have prevented it from becoming invasive. However, genetic
interference through introgression cannot be ruled out
Dyspraxia in a patient with corticobasal degeneration: the role of visual and tactile inputs to action
Objectives-To investigate the roles of visual and tactile information in a dyspraxic patient with corticobasal degeneration (CBD) who showed dramatic facilitation in miming the use of a tool or object when he was given a tool to manipulate; and to study the nature of the praxic and neuropsychological deficits in CBD. Methods-The subject had clinically diagnosed CBD, and exhibited alien limb behaviour and striking ideomotor dyspraxia. General neuropsychological evaluation focused on constructional and visuospatial abilities, calculation, verbal fluency, episodic and semantic memory, plus spelling and writing because impairments in this domain were presenting complaints. Four experiments assessed the roles of visual and tactile information in the facilitation of motor performance by tools. Experiment I evaluated the patient's performance of six limb transitive actions under six conditions: (1) after he described the relevant tool from memory, (2) after he was shown a Line drawing of the tool, (3) after he was shown a real exemplar of the tool, (4) after he watched the experimenter perform the action, (5) while he was holding the tool, and (6) immediately after he had performed the action with the tool but with the tool removed from his grasp. Experiment 2 evaluated the use of the same six tools when the patient had tactile but no visual information (while he was blindfolded). Experiments 3 and 4 assessed performance of actions appropriate to the same six tools when the patient had either neutral or inappropriate tactile feedback-that is, while he was holding a non-tool object or a different tool. Results-Miming of tool use was not facilitated by visual input; moreover, lack of visual information in the blindfolded condition did not reduce performance. The principal positive finding was a dramatic facilitation of the patient's ability to demonstrate object use when he was holding either the appropriate tool or a neutral object. Tools inappropriate to the requested action produced involuntary performance of the stimulus relevant action. Conclusions-Tactile stimulation was paramount in the facilitation of motor performance in tool use by this patient with CBD. This outcome suggests that tactile information should be included in models which hypothesise modality specific inputs to the action production system. Significant impairments in spelling and letter production that have not previously been reported in CBD have also been documented
- …