208 research outputs found
Counterlogicals as Counterconventionals
We develop and defend a new approach to counterlogicals. Non-vacuous counterlogicals, we argue, fall within a broader class of counterfactuals known as counterconventionals. Existing semantics for counterconventionals, 459–482 ) and, 1–27 ) allow counterfactuals to shift the interpretation of predicates and relations. We extend these theories to counterlogicals by allowing counterfactuals to shift the interpretation of logical vocabulary. This yields an elegant semantics for counterlogicals that avoids problems with the usual impossible worlds semantics. We conclude by showing how this approach can be extended to counterpossibles more generally
Application of the QMOM in Research on the Behavior of Solid-liquid Suspensions
The population balance equation (PBE) is a continuity statement written in terms of the number density function. It describes, among others, the aggregation-breakage, nucleation and particle growth phenomena in solid-liquid suspensions. Fast and computationally
inexpensive methods for solving the PBE are very much in demand today for computational fluid dynamics (CFD) simulations, industrial plants designs or scientific research. The Class Method (CM), Monte Carlo method (MC), method of moments (MOM) and its derivatives are the most popular solutions. In this work application of the Mathcad softwarefor the quadrature method of moments (QMOM) is shown. The Mathcad allows one to create a simple and clear algorithm which can be easily changed according to the user
needs, e.g. in modification of an aggregation kernel mathematical formula. The program written can be readily run on a standard PC computer. To verify a correctness of calculations the appropriate measurements were made and an efficiency of the program created
was compared with another one written in the Turbo Pascal language
Vacuum mammotomy under ultrasound guidance
Background: Breast ultrasound is a non-invasive method of breast examination. You can use it also for fine needle biopsy, core needle biopsy, vacuum mammotomy and for placing the "wire" before open surgical biopsy. Material/Methods: 106 patients (105 women and 1 man) aged 20-71 years (mean age 46.9) were treated in Cancer Institute in Cracow by vacuum mammotomy under ultrasound guidance. The lesions found in ultrasonography were divided into three groups: benign lesions (BI RADS II), ambiguous lesions (BI RADS 0, III and IVa), and suspicious lesions (BI RADS IV B, IV C and V). Then lesions were qualified to vacuum mammotomy. Results: According to USG, fibroadenoma or "fibroadenoma-like" lesions were found in 75 women, in 6 women complicated cysts, in 6 women cyst with dense fluid (to differentiate with FA), and in 19 patients undefined lesions. Fibroadenoma was confirmed in histopathology in 74% patients among patients with fibroadenoma or "fibroadenoma-like" lesions in ultrasound (in others also benign lesions were found). Among lesions undefined after ultrasound examination (total 27 patients) cancer was confirmed in 6 % (DCIS and IDC). In 6 patients with complicated cysts in ultrasound examination, histopathology confirmed fibroadenoma in 4 women, an intraductal lesion in 1 woman and inflamatory process in 1 woman. Also in 6 women with a dense cyst or fibroadenoma seen in ultrasound, histopathology confirmed fibroadenoma in 3 women and fibrosclerosis in 3 women. Conclusions: Any breast lesions undefined or suspicious after ultrasound examination should be verified. The method of verification or kind of operation of the whole lesion (vacuum mammotomy or "wire") depends on many factors, for example: lesion localization; lesion size; BI RADS category
Model for a dune field with exposed water table
Aeolian transport in coastal areas can be significantly affected by the
presence of an exposed water table. In some dune fields, such as in
Len\c{c}\'ois Maranhenses, northeastern Brazil, the water table oscillates in
response to seasonal changes of rainfall and rates of evapotranspiration,
rising above the ground during the wet season and sinking below in the dry
period. A quantitative understanding of dune mobility in an environment with
varying groundwater level is essential for coastal management as well as for
the study of long-term evolution of many dune fields. Here we apply a model for
aeolian dunes to study the genesis of coastal dune fields in presence of an
oscillating water table. We find that the morphology of the field depends on
the time cycle, , of the water table and the maximum height,
, of its oscillation. Our calculations show that long chains of
barchanoids alternating with interdune ponds such as found at Len\c{c}\'ois
Maranhenses arise when is of the order of the dune turnover
time, whereas dictates the growth rate of dune height with
distance downwind. We reproduce quantitatively the morphology and size of dunes
at Len\c{c}\'ois Maranhenses, as well as the total relative area between dunes.Comment: 12 pages, 12 figure
Aeolianite and barrier dune construction spanning the last two glacial-interglacial cycles from the southern Cape coast, South Africa
The southern Cape region of South Africa has extensive coastal aeolianites and barrier dunes. Whilst previously reported, limited knowledge of their age has precluded an understanding of their relationship with the climatic and sea-level fluctuations that have taken place during the Late Quaternary. Sedimentological and geomorphological studies combined with an optical dating programme reveal aeolianite development and barrier dune construction spanning at least the last two glacial–interglacial cycles. Aeolianite deposition has occurred on the southern Cape coast at ca 67–80, 88–90, 104–128, 160–189 and >200 ka before the present. Using this and other published data coupled with a better understanding of Late Quaternary sea-level fluctuations and palaeocoastline configurations, it is concluded that these depositional phases appear to be controlled by interglacial and subsequent interstadial sea-level high stands. These marine transgressions and regressions allowed onshore carbonate-rich sediment movement and subsequent aeolian reworking to occur at similar points in the landscape on a number of occasions. The lack of carbonates in more recent dunes (Oxygen Isotope Stages 1/2 and 4/5) is attributed not to leaching but to changes to carbonate production in the sediment source area caused by increased terrigenous material and/or changes in the balance between the warm Agulhas and nutrient-rich Benguela ocean current
Linear stability analysis of transverse dunes
Sand-moving winds blowing from a constant direction in an area of high sand
availability form transverse dunes, which have a fixed profile in the direction
orthogonal to the wind. Here we show, by means of a linear stability analysis,
that transverse dunes are intrinsically unstable. Any along-axis perturbation
on a transverse dune amplify in the course of dune migration due to the
combined effect of two main factors, namely: the lateral transport through
avalanches along the dune's slip-face, and the scaling of dune migration
velocity with the inverse of the dune height. Our calculations provide a
quantitative explanation for recent observations from experiments and numerical
simulations, which showed that transverse dunes moving on the bedrock cannot
exist in a stable form and decay into a chain of crescent-shaped barchans.Comment: 8 pages, 4 figure
Crystal structure of the TreS-Pep2 complex, initiating α-glucan synthesis in the GlgE pathway of mycobacteria
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