343 research outputs found
Concurrent Design of Railway Vehicles by Simulation Model Reuse
This paper describes a concurrent design approach to railway vehicle design. Current railway vehicles use many different concepts that are combined into the final design concept. The design support for such systems is based on reusing components from previous design cases. The key part of the railway vehicle design concept is its simulation model. Therefore the support is based on support for reuse of previous simulation models. The simulation models of different railway component concepts are stored using the methodology from the EU CLOCKWORK project. The new concept usually combines stored components
Binary self-similar one-dimensional quasilattices: Mutual local-derivability classification and substitution rules
Self-similar binary one-dimensional (1D) quasilattices (QLs) are classified
into mutual local-derivability (MLD) classes. It is shown that the MLD
classification is closely related to the number-theoretical classification of
parameters which specify the self-similar binary 1D QLs. An algorithm to derive
an explicit substitution rule, which prescribes the transformation of a QL into
another QL in the same MLD class, is presented. An explicit inflation rule,
which prescribes the transformation of the self-similar 1D QL into itself, is
obtained as a composition of the explicit substitution rules. Symmetric
substitution rules and symmetric inflation rules are extensively discussed.Comment: 24 pages, 4 figures, submitted to PR
Phase-dependent which-way information
We introduce a new observable for reading out a which-way detector in a
Young-type interferometer whose eigenstates either contain full which-way
information or none at all. We calculate the which-way knowledge K that can be
retrieved from this observable and find that K depends on the phase difference
\delta that the interfering object accumulates on its way from either slit to
the detector. In particular, it turns out that K(\delta) has an upper bound of
1, almost independent of the visibility V of the interference pattern generated
by the interfering object on a screen, which is in marked contrast to the
well-known inequality K^2 + V^2 <= 1 (cf. B.-G. Englert, Phys. Rev. Lett. 77,
2154 (1996)).Comment: 7 pages, 4 figure
Resistance to Antibiotics in Strains of Staphylococcus spp., Enterococcus spp. and Escherichia coli Isolated from Rectal Swabs of Pigs
The study aimed at determining the level of resistance of selected bacterial species (Staphylococcus spp., Enterococcus spp., Escherichia coli) isolated from rectal swabs of pigs to antimicrobial agents. The tested strains were isolated from piglets aged 7 to 30 days. Bacterial species were identified by standard microbiological techniques and susceptibility to antibiotics was determined quantitatively by the standard microdilution method. Resistance of the Staphylococcus aureus strain to oxacillin was confirmed by detection of the mecA gene and PBP2a. A total of 115 Staphylococcus spp. isolates were collected. In the case of Staphylococcus aureus, the methicillin-resistant strain (MRSA) was identified. Moreover, higher frequency of coagulase-negative staphylococci with minimum inhibitory concentration of oxacillin ≥ 0.5 mg/l was noticed. Inducible resistance to clindamycin in the Staphylococcus hominis strain was also detected. The strains of Enterococcus spp. (61 isolates) exhibited high resistance to tetracycline (98.5%), erythromycin (86.8%) and chloramphenicol (54.4%). Vancomycin-resistant enterococci were not isolated. In the case of Escherichia coli strains (111 isolates), higher frequency of resistant strains to tetracycline (81.1%) and ampicillin (62.2%) was documented. Resistance to fluoroquinolones and production of broad-spectrum β-lactamases was not noticed. The presented study may be considered as a pilot project assessing the prevalence of resistant bacteria in piglets kept on a single farm. It demonstrated the presence of resistant strains of Staphylococcus spp., including one MRSA strain, Enterococcus spp. and Escherichia coli. These strains may be present as a result of postnatal colonization with both bacterial microflora of dams and environmental microflora
Quantum bath refrigeration towards absolute zero: unattainability principle challenged
A minimal model of a quantum refrigerator (QR), i.e. a periodically
phase-flipped two-level system permanently coupled to a finite-capacity bath
(cold bath) and an infinite heat dump (hot bath), is introduced and used to
investigate the cooling of the cold bath towards the absolute zero (T=0).
Remarkably, the temperature scaling of the cold-bath cooling rate reveals that
it does not vanish as T->0 for certain realistic quantized baths, e.g. phonons
in strongly disordered media (fractons) or quantized spin-waves in ferromagnets
(magnons). This result challenges Nernst's third-law formulation known as the
unattainability principle
Trace and antitrace maps for aperiodic sequences, their extensions and applications
We study aperiodic systems based on substitution rules by means of a
transfer-matrix approach. In addition to the well-known trace map, we
investigate the so-called `antitrace' map, which is the corresponding map for
the difference of the off-diagonal elements of the 2x2 transfer matrix. The
antitrace maps are obtained for various binary, ternary and quaternary
aperiodic sequences, such as the Fibonacci, Thue-Morse, period-doubling,
Rudin-Shapiro sequences, and certain generalizations. For arbitrary
substitution rules, we show that not only trace maps, but also antitrace maps
exist. The dimension of the our antitrace map is r(r+1)/2, where r denotes the
number of basic letters in the aperiodic sequence. Analogous maps for specific
matrix elements of the transfer matrix can also be constructed, but the maps
for the off-diagonal elements and for the difference of the diagonal elements
coincide with the antitrace map. Thus, from the trace and antitrace map, we can
determine any physical quantity related to the global transfer matrix of the
system. As examples, we employ these dynamical maps to compute the transmission
coefficients for optical multilayers, harmonic chains, and electronic systems.Comment: 13 pages, REVTeX, now also includes applications to electronic
systems, some references adde
Beyond technology: pottery reveals translocal social relations at a Bell Beaker Monumental Site in Central Europe
The Bell Beaker site near Brodek u Prostějova (Czechia) has yielded remains of a large timber construction accompanied by four symmetrical ritual deposits with numerous artefacts, including more than fifty ceramic vessels. Their decoration consists of incised patterns, in nineteen cases with preserved white inlaid incrustations. To investigate the social relations at this extraordinary site, a multi-analytical and micro-destructive approach was employed to determine the provenance and technology of the pottery and the composition of the white incrustations. The results indicate various origins for the pottery within the region and the presence of extra-regional fabrics and graphitic temper. The main raw materials for the white inlays were calcium carbonate (calcite), hydroxyapatite (bone), and bright clay. The mixing of decorative motifs and the variation in the shape and size of the beakers suggest unique manufacturing processes. These results lend support to the monumental site of Brodek serving as a ritual place for several communities from both local and wider areas.Introduction Materials and methods Results - Ceramic petrography and chemical composition White inlay incrustations - Micro Fourier transform infrared spectroscopy (μFTIR) - Micro X-ray diffraction (μXRD) - Scanning electron microscopy-electron dispersive spectroscopy (SEM-EDS) Metrics abd decoration analysis Discussion - Ceramic provenance and materials of white incrustations - Depositional semantics and ceramic patterns in the ritual features - Translocal social relationships and the circulation of ceramics and other artefacts Conclusio
Minimizing energy below the glass thresholds
Focusing on the optimization version of the random K-satisfiability problem,
the MAX-K-SAT problem, we study the performance of the finite energy version of
the Survey Propagation (SP) algorithm. We show that a simple (linear time)
backtrack decimation strategy is sufficient to reach configurations well below
the lower bound for the dynamic threshold energy and very close to the analytic
prediction for the optimal ground states. A comparative numerical study on one
of the most efficient local search procedures is also given.Comment: 12 pages, submitted to Phys. Rev. E, accepted for publicatio
VLIV FOTODYNAMICKÉ TERAPIE NA CYTOMECHANIKU NÁDOROVÉ BUNĚČNÉ LINIE HELA
Během posledních desetiletí byla k zobrazování detailních struktur biologických preparátů používána zejména elektronová mikroskopie (EM). Ačkoliv nám EM poskytuje vysoké rozlišení; zobrazovat vzorky bez fixace a barvení není zcela jednoduché a je tímto limitováno. Jak se ale ukazuje, mikroskopie atomárních sil (AFM) se zdá být vhodným nástrojem nejen pro zobrazení biologických struktur, ale i k jejich manipulaci s nimi v nativním stavu a v přirozeném prostředí. Navíc nám poskytuje přesné morfologické a mechanické informace v reálném čase a v nanorozlišení. Moderní AFM přístroj pracuje s pikonewtonovou silovou interakcí s povrchem preparátu, což nám umožňuje provádět detailní studie mofrologických charakterizací biologického vzorku a popisy interakcí hrot-vzorek. Jako biologický objekt byla vybrána HeLa buněčná linie (nádor děložního hrdla virového původu), která je citlivá vůči fotodynamické terapii za současného využití ftalocyaninového senzitizeru. Pro detekci změn v buněčné kultuře byly použity dva různé mikroskopy atomárních sil: Bioscope Catalyst od firmy Bruker a Ntegra AURA od firmy NT-MDT jako nástroj pro detekci mechanických změn po terapii. Naše práce má za úkol upozornit na jednu z aplikací mikroskopie atomárních sil - mechanickou charakterizaci buněk před a po poškození fotodynamickou terapií, která může mít výhledově velký přínos v diagnostice různých onemocnění
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