Structure Factor and Diffraction

The average percentage of residents restrained in nursing homes is approximately 20%. Facilities that do not meet Health Care Financing Administration standards for restraint use may be issued a deficiency citation. This article investigates which structure and process factors of nursing homes are associated with a deficiency citation for restraint use. Nationally representative data from the 1997 On-line Survey Certification of Automated Records are used, first, to provide descriptive analyses, and second, for logistic regression analyses of structure and process factors associated with a deficiency citation for restraint use. A total of 2,321 facilities were found to have at least one restraint deficiency citation, and 14,703 had none. After controlling for seven other key variables, five structural factors and six process factors are significant. The structural factors--larger bed size, for-profit ownership, and hospital based--were significantly associated with a higher likelihood of a deficiency citation for restraint use; whereas higher numbers of full-time equivalent specialists per resident and nurse aide training were significantly associated with a lower likelihood. The process factors--suctioning therapy, pain management, and bladder training--were significantly associated with a lower likelihood of a deficiency citation for restraint use; whereas intravenous therapy, higher use of catheters, and physical restraints were significantly associated with a higher likelihood of a deficiency citation. This analysis establishes linkages between structures and processes and the outcome of a deficiency citation for restraint use. The structural results may have some utility for regulators. They could be used to develop a specific program to target facilities most commonly found to have inappropriate restraint use. The process results may have some utility for providers who could use the information to target residents for review of inappropriate restraint use.

Comparison of convergent beam electron diffraction methods for simultaneous structure and Debye Waller factor determination

High-temperature series expansion for spin-1/2 Heisenberg models

ABSTRACTAim: to investigate the relationship between ICF “body functions and structure factors” and the “activity-participation” of community-dwelling older adults. Methods: 41 healthy older adults (age range 65–92 years) from Tasmania, Australia completed the Bruininks Motor Ability Test (BMAT), Leisure Satisfaction Measure, Lawton Instrumental Activities of Daily Living, Keele Assessment of Participation, and the Activity Card Sort (Australian version). Spearman Rho correlation and linear regression analyses were completed to investigate relationships between the dependent and independent variables. Results: Co-ordination, and Balance and Mobility subscale scores on the BMAT had no association with activity-participation while the BMAT Fine Motor Integration and Manual Dexterity subscale scores were predictive of their activity-participation. Conclusions: The findings indicate that body function and structure factors (related to fine motor skills) were associated with and predictive of older adults” activity-participation. Further research is needed to investigate the link between body structure and function factors and older adults” activity-participation levels.

Aggregation processes are central features of many systems ranging from colloids and polymers to inorganic nanoparticles and biological systems. Some aggregated structures are controlled and desirable, e.g. in the design of size-controlled clustered nanoparticles or some protein-based drugs. In other cases, the aggregates are undesirable, e.g. protein aggregation involved in neurodegenerative diseases or in vitro studies of single protein structures. In either case, experimental and analytical tools are needed to cast light on the aggregation processes. Aggregation processes can be studied with small-angle scattering, but analytical descriptions of the aggregates are needed for detailed structural analysis. This paper presents a list of useful small-angle scattering structure factors, including a novel structure factor for a spherical cluster with local correlations between the constituent particles. Several of the structure factors were renormalized to get correct limit values in both the high-q and low-q limit, where q is the modulus of the scattering vector. The structure factors were critically evaluated against simulated data. Structure factors describing fractal aggregates provided approximate descriptions of the simulated data for all tested structures, from linear to globular aggregates. The addition of a correlation hole for the constituent particles in the fractal structure factors significantly improved the fits in all cases. Linear aggregates were best described by a linear structure factor and globular aggregates by the newly derived spherical cluster structure factor. As a central point, it is shown that the structure factors could be used to take aggregation contributions into account for samples of monomeric protein containing a minor fraction of aggregated protein. After applying structure factors in the analysis, the correct structure and oligomeric state of the protein were determined. Thus, by careful use of the presented structure factors, important structural information can be retrieved from small-angle scattering data, both when aggregates are desired and when they are undesired.

Ontology represents a structured view of the domain containing rich semantic meanings, thus plays an important role for various knowledge-intensive applications. Domain ontology contains the concept of complete information and extensive links between concepts. Construction of agricultural domain ontology can provide the foundation of knowledge organization for vertical agricultural research engine and promoting agricultural informationization and realizing cooperative service of agricultural information. Semantic similarity measure plays an important role in information retrieval and information integration based on ontology. While, traditional semantic similarity algorithms of domain ontology only focus on single influencing factor, which leads to poor convergence performances, lower accuracy, strong subjectivity and other defects. In this paper, a weighted semantic similarity algorithm based on agricultural domain ontology was proposed. According to the characteristics of the different structure of ontology, the major factors that influence the similarity are the structure factor, property of the concept, information, etc. But the structural factors are impacted by relationship type, density of node, depth of node and other factors. First, according to the structural characteristics of ontology model, a new method for calculating the node density was proposed in this study. At the same time, an integrated structure similarity model based on relationship type, node density, depth integrated structure similarity, semantic distance was given, which was called the structure factors. Second, according to the literature and empirical knowledge, the property grid of ontology concept pairs was accessed to gain the attributes of the concept. Third, according to ontology hierarchial network, B-U probability based on root and leaf nodes and semantic information was calculated, which did not rely on the expertise and was objective. Fourth, combining semantic structure, information and property factors, an integrated semantic similarity algorithm was proposed, which considered that different impact factors had a different important degree in the calculation of semantic similarity and were given different weights to agricultural ontology relations. Finally, taking semantic similarity computation of part of agriculture ontology for example, the calculation process of semantic similarity on sweet corn and waxy maize was enumerated in detail. According to the semantic similarity algorithm proposed in this paper, comparing the calculation results of semantic similarity (0.8206) and standard deviation (0.0565) with other algorithms, it was closer to the intuitive cognition and expert advice, which can effectively improve the accuracy and validity of semantic similarity computation. In this paper, we presented the effort of computing the semantic similarity values via studying the relationship between concept pairs of agricultural ontologies at different depth of ontology hierarchical structure. We evaluated the accuracy of semantic similarity calculation between four different algorithms (algorithm in this paper, algorithm based on information content, algorithm based on distance, and algorithm using standard deviation commonly applied in statistics). The results of this study demonstrated that with proper selection of parameters and comprehensive similarity computation measures, we can significantly reduce difficulty of distinguishing the concept of weak correlation. This study provides a deeper understanding of the application of semantic similarity to agricultural ontologies, and shows how to choose appropriate semantic similarity measures for agricultural information retrieval. © 2016, Editorial Department of the Transactions of the Chinese Society of Agricultural Engineering. All right reserved.

# 1999 International Union of Crystallography Printed in Great Britain ± all rights reserved The Protein Data Bank (PDB) has long made available the experimental data which were used to determine the three-dimensional structures in the database. In recent years more and more depositors and users of the PDB have come to appreciate the importance of reliable access to such fundamental data. The deposition of the experimental data, along with the coordinates is essential for the following reasons. (i) Rigorous validation of the structuredetermination results can only be carried out using both atomic parameters and experimental structure-factor amplitudes. (ii) Archiving of this data will ensure their preservation and continued accessibility. Whether or not to require that the experimental data be deposited concomitantly with the structure data has been hotly discussed recently in the scienti®c press [Baker, Blundell, Vijayan, Dodson, Dodson, Gilliland & Sussman (1996). Nature (London), 379, 202] and on the internet (EBI/MSD Draft Consultative Document for Deposition of Structure Factors http://croma.ebi.ac.uk/msd/Policy/sf.html). At present more than 50% of the X-ray diffraction submissions are being deposited with their associated structure factors (see Table 1), compared with 25% four years ago. This increase is probably partly due to the ease of uploading the ®les via our WWW-based submission tool, AutoDep, and the fact that this tool is available both in the USA at BNL (PDB deposition site at http://www.pdb. bnl.gov) and in Europe at the EBI (EBI deposition site at http://www2.ebi.ac.uk/pdb). The PDB strongly encourages all researchers to deposit their structure factors at the time of coordinate submission. Furthermore, we actively encourage journals to require their submission as a prerequisite for publication [Sussman (1996). Protein Data Bank Quart. Newslett. No. 75, p. 1, at ftp://pdb.pdb.bnl.gov/ newsletter/newsletter96jan/newslttr.txt]. In order to facilitate the use of deposited structure factors, we at the PDB, together with a number of macromolecular crystallographers and the IUCr Working Group on Macromolecular CIF, developed a standard interchange format for structure factors [PDB Structure Factor mmCIF at ftp://pdb. pdb.bnl.gov/pub/pdb/structure_factors/cifSF_ dictionary; Protein Data Bank Quart. Newslett. No. 74, p. 1 (1995), at ftp://pdb.pdb.bnl.gov/ newsletter/newsletter95oct/newslttr.tx]. This standard is the mmCIF format, i.e. the IUCrdeveloped Macromolecular Crystallographic Information File. It was chosen for its simplicity of design and for being clearly selfde®ning. The format is also easy to expand, as new crystallographic experimental methods or concepts are developed, by simply adding additional tokens. The entire mmCIF crystallographic dictionary (http://ndb.rutgers.edu/ NDB/mmcif) has recently been rati®ed by the IUCr's COMCIFS committee. The PDB has written a program to quickly and easily convert structure factors, as output by the most frequently used crystallographic programs, into the mmCIF format. This tool, which also converts binary CCP4 MTZ ®les, will be accessible through the AutoDep program following ®nal testing. MTZ ®les, which are useful in individual laboratories, are not appropriate for archival purposes. This is because particular groups arbitrarily attach different labels to the MTZ columns. During the past year, the PDB has converted virtually all the old structure-factor ®les to this standard format and is keeping up-to-date on all new submissions. As of November 1998, there 2 000 structure-factor ®les released in the structure-factor mmCIF format (PDB mmCIF structure-factor ®les can be found at ftp://pdb. pdb.bnl.gov/pub/pdb/structure_factors/CIF_ format), with an additional 1 300 `on-hold' for uptofouryearsaccordingtotheIUCrpolicy(see IUCr deposition policy at http://www.iucr.org/ iucr-top/journals/acta/actad_notes.html). The structure factors are also available through the PDB's WWW-based 3DB Browser (http:// www.pdb.bnl.gov/pdb-bin/pdbmain). This can be seen on the browser's atlas page for each structure. The ready availability of structure-factor ®les in a standard format has made it possible for any scientist to validate a structure in the PDB versus its experimentally observed data. There are now some excellent tools available for this, such as SFCHECK (http://www.iucr.org/iucrtop/comm/ccom/School96/pdf/sw.pdf) and the Uppsala Electron Density Server (http://alpha2. bmc.uu.se/valid/density/form1.html). The PDB has also observed that one of the most popular uses for these stored structure factors is for the crystallographer who did the experiment to be able to retrieve his/her own data which have been misplaced in their laboratory. Table 1 PDB structure-factor (SF) submission.

The indirect Fourier transformation (IFT) is the method of choice for the model-free evaluation of small-angle scattering data. Unfortunately, this technique is only useful for dilute solutions because, for higher concentrations, particle interactions can no longer be neglected. Thus an advanced technique was developed as a generalized version, the so-called generalized indirect Fourier transformation (GIFT). It is based on the simultaneous determination of the form factor, representing the intraparticle contributions, and the structure factor, describing the interparticle contributions. The former can be determined absolutely free from model assumptions, whereas the latter has to be calculated according to an adequate model. In this paper, various models for the structure factor are compared,e.g.the effective structure factor for polydisperse hard spheres, the averaged structure factor, the local monodisperse approximation and the decoupling approximation. Furthermore, the structure factor for polydisperse rod-like particles is presented. As the model-free evaluation of small-angle scattering data is an essential point of the GIFT technique, the use of a structure factor without any influence of the form amplitude is advisable, at least during the first evaluation procedure. Therefore, a series of simulations are performed to check the possibility of the representation of various structure factors (such as the effective structure factor for hard spheres or the structure factor for rod-like particles) by the less exact but much simpler averaged structure factor. In all the observed cases, it was possible to recover the exact form factor with a free determined parameter set for the structure factor. The resulting parameters of the averaged structure factor have to be understood as apparent model parameters and therefore have only limited physical relevance. Thus the GIFT represents a technique for the model independent evaluation of scattering data with a minimum ofa prioriinformation.

We perform a quite detailed theoretical investigation of the temperature dependence of the static and dynamical structure factors for undercooled potassium. The static structure factors are calculated from the hybridized mean-spherical approximation (HMSA) form of the integral approximation using pair potentials constructed from a non-local pseudopotential and the dynamical structure factors within the viscoelastic approximation. We show that the characteristic features of the static structure factors as obtained from molecular dynamics simulation are reproduced within the present framework and that, essentially, the general features of at the melting points are still preserved in the undercooled region.

We present the behaviors of both dynamical and static charge susceptibilities of doped armchair nanotubes using the Green function approach in the context of Holstein-model Hamiltonian. Specially, the effects of magnetization and gap parameter on the the plasmon modes of armchair nanotube are investigated via calculating correlation function of charge density operators. Random phase approximation has been implemented to find the interacting dynamical charge susceptibility. The electrons in this systems interacts with each other by mediation of dispersionless Holstein phonons. Our results show that the increase of gap parameter leads to decreasing intensity of charge collective mode. Also the frequency position of the collective mode tends to higher frequencies due to the gap parameter. Furthermore the number of collective excitation mode decreases with chemical potential in the presence of electron–phonon interaction. Finally the temperature dependence of static charge structure factor of armchair nanotubes is studied. The effects of the gap parameter, magnetization and electron–phonon interaction on the static structure factor are addressed in details.

We present the behaviors of both dynamical and static spin susceptibilities of doped gapped armchair graphene nanoribbon using the Green’s function approach in the context of Hubbard model Hamiltonian. Specially, the effects of spin polarization and gap parameter on the spin excitation modes of armchair graphene nanoribbon are investigated via calculating correlation function of spin density operators. Our results show the increase of electron concentration leads to disappear low frequency spin excitation mode for gapless case. We also show that low frequency excitation mode for both gapped and gapless nanoribbon disappears under spin full polarization condition. Finally, the electron density dependence of static charge structure factor of armchair graphene nanoribbon is studied. The effects of both gap parameter and magnetic ordering on the static structure factor are discussed in details.

Spin structure factors and valence-bond-solid states of the trimerized Heisenberg chains in a magnetic field

Poly- and oligotetrafluoroethylenes exhibit at room temperature a high molecular mobility in the crystalline state. A detailed analysis of the molecular motion is possible by measuring the static and dynamic structure factor using x-ray and neutron scattering. The onset of diffusive molecular dynamics coincides in poly- and oligotetrafluoroethylenes with an orderdisorder phase transition. — In PTFE the prevalent relaxational mode is a double helix reversal. Occurrence of helix reversals leads to a characteristic change in the static structure factor S(q), indicating a loss of azimuthal correlation within the chain. A quasieelastic line in the dynamic structure factor S(q, ω) can be associated with motion of helix reversals. Six-fold symmetry (around the chain axis) of the intensity distribution of the diffusive scattering indicates an intermolecular correlation of rotational motion. — In C20F42 the phase transition at 200 K is mainly connected with the onset of rotational motion. Additionally, longitudinal diffuse motion sets in at the phase transition. This mode shows an increasingly collective character on approaching the phase transition.

Static and dynamic structure of liquids and glasses

Transverse spin susceptibilities of doped armchair graphene nanoribbon due to electron-phonon interaction