177,065 research outputs found
High-functionality star-branched macromolecules: Polymer size and virial coefficients
No full textWe perform high-statistics Monte Carlo simulations of a lattice model to compute the radius of gyration R-g, the center-to-end distance, the monomer distribution, and the second and third virial coefficients of star polymers for a wide range of functionalities f, 6 infinity. Structural results are finally compared with the predictions of the Daoud-Cotton model. It turns out that the blob picture of a star polymer is essentially correct up to the corona radius R-c, which depends on f and which varies from 0.7R(g) for f = 6 to 1.0R(g) for f = 40. The outer region (r > R-c), in which the monomer distribution decays exponentially, shrinks as f increases, but it does not disappear in the scaling regime even in the limit f -> infinity. We also consider the Daoud-Cotton scaling relation R-g(2) similar to f(1-nu)L(2 nu), which is found to hold only for f >> 100. (C) 2013 AIP Publishing LLC
Thermodynamics of star polymer solutions: A coarse-grained study
No full textWe consider a coarse-grained (CG) model with pairwise interactions, suitable to describe low-density solutions of star-branched polymers of functionality f. Each macromolecule is represented by a CG molecule with (f + 1) interaction sites, which captures the star topology. Potentials are obtained by requiring the CG model to reproduce a set of distribution functions computed in the microscopic model in the zero-density limit. Explicit results are given for f = 6, 12, and 40. We use the CG model to compute the osmotic equation of state of the solution for concentrations c such that Φp = c/c∗ = 1, where c∗ is the overlap concentration. We also investigate in detail the phase diagram for f = 40, identifying the boundaries of the solid intermediate phase. Finally, we investigate how the polymer size changes with c. For Φp less than 0.3, polymers become harder as f increases at fixed reduced concentration c/c∗. On the other hand, for Φp larger than 0.3, polymers show the opposite behavior:At fixed Φp, the larger the value of f, the larger their size reduction is
“Punishment for the Sinner”: Holocene episodic subsidence and steady tectonic motion at ancient Sybaris (Calabria, southern Italy).
No full textAlthough the Calabria region in southern Italy experienced Quaternary uplift, intense Holocene subsidence
is documented at ancient Sybaris, one of the most powerful among the Greek colonies collectively known
as Magna Greacia. Sybaris flourished along the Ionian Sea coast of north-eastern Calabria since 2.7 ka BP
and until the end of the Roman empire, when it went progressively concealed below the ground. Study of
the Latest PleistoceneeHolocene evolution of this area involved analysis of the relative sea-level history for
individual borehole logs, based on re-calibration of published ages and stipulation of nominal sea-level
positions related to each marker. For investigation of the short-term evolution, a novel compilation of
geological and archaeological sea-level markers was supported by new radiometric ages. Appraisal of the
position of dated markers, when compared to a sea-level curve built on purpose for this coast using an
updated glacio-hydro-isostatic model, indicates a locally intense difference in vertical motion between
boreholes located away from, or close to, the ancient town. Specifically, whereas data from the basement of
the archaeological layers document large subsidence, more distant sites behaved differently. A site w2 km
to the NW of the settlement was apparently stable throughout the Holocene, and a site w6 km to the SE
experienced uplift at w1.5mm/y since 0.6 ka BP. In addition, analysis reveals temporal changes in subsidence
pattern in the archaeological area. Large (5e6 mm/y) Early Holocene subsidence at Sybaris slowed to
w1.5mm/y during the middle part of the Holocene. The slowing-down trend continued during and after
historical occupation at w0.8 mm/y, a value similar to the long-term (35e40 ka BP) rate established from
the deepest borehole samples. These data are interpreted as suggesting that sediment compaction affected
the basement of Sybaris during the Early Holocene, and progressively ceased during historical times, when
a tectonic signal prevailed. During historical time, the spatial difference in vertical motion is chiefly
attributed to differential growth of nearby folds documented by morpho-tectonic studies on-land and
seismic profiles analysis in the offshore of Sybaris. Whereas location above a syncline caused tectonic
subsidence at Sybaris, the regions to the north and south record stability or uplift that reflects transition to
growing anticlines. In the short term (1e10 ka scale), these local tectonic processes prevail over the
regional uplift pattern, which is expressed at the 100 ka scale or over
Holocene episodic subsidence and steady tectonic motion at the ancient Sybaris (Calabria, southern Italy)
No full textAppropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Improving the quality of medical records
No full textBACKGROUND: Medical record is an essential tool both in patients’ diagnostic and therapeutic pathways and communication between different care providers. It also has an economic-administrative, medical-legal and epidemiological function. From an economic-administrative point of view, a medical record allows an evaluation and review of services to better manage the corporate health budget. In addition, it allows traceability and complete transparency of the health activities carried out. The study evaluates the formal quality of medical records compiled in an Italian private clinic before and after a training intervention. METHODS: In June 2019, a retrospective study was carried out to assess a private clinic’s quality of medical records. One month later, healthcare providers were trained on the appropriate compilation of medical records, whose pre-printed format was structurally improved. In March 2020, we verified the quality of medical records produced after that training intervention. Statistical analysis (Wilcoxon test) was carried out through Stata. RESULTS: A total of 149 medical records were reviewed. Statistically significant improvements (p < 0,05), between before and after training intervention, were for overall readability (33.3% vs 74.7%), completeness of admission and discharge dates (33.3% vs 74.40%), for completeness of anamnesis (13.6% vs 63.9%), for completeness of therapeutic card (53% vs 85.5%), in the reduction of non-compliance corrections (22.7% vs 4.8%), signature presence of physical examination (34.9% vs 71.1%) and for signature presence in the hospital discharge card (86.4% vs 96.4%). CONCLUSIONS: The results show that simple measures, such as staff training and restructuring of the format, are effective in improving the quality of medical records. KEY MESSAGES: • Healthcare providers should perceive the proper completion of medical records as a common goal. • Well-completed medical records contribute to better health care
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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