75 research outputs found
Generalized Strong Curvature Singularities and Cosmic Censorship
A new definition of a strong curvature singularity is proposed. This
definition is motivated by the definitions given by Tipler and Krolak, but is
significantly different and more general. All causal geodesics terminating at
these new singularities, which we call generalized strong curvature
singularities, are classified into three possible types; the classification is
based on certain relations between the curvature strength of the singularities
and the causal structure in their neighborhood. A cosmic censorship theorem is
formulated and proved which shows that only one class of generalized strong
curvature singularities, corresponding to a single type of geodesics according
to our classification, can be naked. Implications of this result for the cosmic
censorship hypothesis are indicated.Comment: LaTeX, 11 pages, no figures, to appear in Mod. Phys. Lett.
On Unbounded Composition Operators in -Spaces
Fundamental properties of unbounded composition operators in -spaces are
studied. Characterizations of normal and quasinormal composition operators are
provided. Formally normal composition operators are shown to be normal.
Composition operators generating Stieltjes moment sequences are completely
characterized. The unbounded counterparts of the celebrated Lambert's
characterizations of subnormality of bounded composition operators are shown to
be false. Various illustrative examples are supplied
Applications of distance between probability distributions to gravitational wave data analysis
We present a definition of the distance between probability distributions.
Our definition is based on the norm on space of probability measures. We
compare our distance with the well-known Kullback-Leibler divergence and with
the proper distance defined using the Fisher matrix as a metric on the
parameter space. We consider using our notion of distance in several problems
in gravitational wave data analysis: to place templates in the parameter space
in searches for gravitational-wave signals, to assess quality of search
templates, and to study the signal resolution.Comment: 18 pages, 5 figure
The phenology of winter rye in Poland: an analysis of long-term experimental data
The study of the phenology of crops, although quite popular, has limitations, mainly because of frequent changes to crop varieties and management practices. Here, we present data on the phenology and yield of winter rye in western Poland collected between 1957 and 2012 from a long-term field experiment. Data were examined for trends through time and compared to climatological factors using regression analysis. Both annual air temperature and precipitation increased during the study period, equivalent to 2 °C and 186 mm, respectively, over the 52-year period for which met data were available. We detected significant delays in sowing date and recently in emergence, but significant advances were apparent in full flowering date equivalent to 4 days/decade. Yield and plant density experienced a step like change in 1986; yield increasing by ca. 70 % and plant density increasing by ca. 50 %, almost coinciding with a similar change in annual mean temperature, but most likely caused by a changed seed rate and use of herbicides. Future climate change is expected to have a greater impact on this crop, but farmers may be able to adapt to these changes by modifying water regimes, using new machinery and sowing new rye varieties
All-sky search of NAUTILUS data
A search for periodic gravitational-wave signals from isolated neutron stars
in the NAUTILUS detector data is presented. We have analyzed half a year of
data over the frequency band Hz/s and over the entire sky. We have divided the
data into 2 day stretches and we have analyzed each stretch coherently using
matched filtering. We have imposed a low threshold for the optimal detection
statistic to obtain a set of candidates that are further examined for
coincidences among various data stretches. For some candidates we have also
investigated the change of the signal-to-noise ratio when we increase the
observation time from two to four days. Our analysis has not revealed any
gravitational-wave signals. Therefore we have imposed upper limits on the
dimensionless gravitational-wave amplitude over the parameter space that we
have searched. Depending on frequency, our upper limit ranges from to . We have attempted a statistical
verification of the hypotheses leading to our conclusions. We estimate that our
upper limit is accurate to within 18%.Comment: LaTeX, 12 page
Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run
We summarize the sensitivity achieved by the LIGO and Virgo gravitational
wave detectors for compact binary coalescence (CBC) searches during LIGO's
fifth science run and Virgo's first science run. We present noise spectral
density curves for each of the four detectors that operated during these
science runs which are representative of the typical performance achieved by
the detectors for CBC searches. These spectra are intended for release to the
public as a summary of detector performance for CBC searches during these
science runs.Comment: 12 pages, 5 figure
Sensitivity to Gravitational Waves from Compact Binary Coalescences Achieved during LIGO's Fifth and Virgo's First Science Run
We summarize the sensitivity achieved by the LIGO and Virgo gravitational wave detectors for compact binary coalescence (CBC) searches during LIGO's fifth science run and Virgo's first science run. We present noise spectral density curves for each of the four detectors that operated during these science runs which are representative of the typical performance achieved by the detectors for CBC searches. These spectra are intended for release to the public as a summary of detector performance for CBC searches during these science runs
Proposition of a new method for the calculation of diagonal crack widths in reinforced concrete elements subjected to combined torsion and shear
Artykuł dotyczy zjawiska zarysowania skręcanych elementów żelbetowych, które jednocześnie poddane są działaniu siły poprzecznej. Zaprezentowano model teoretyczny Rahala i Collinsa, który jest jedynym modelem dającym możliwość szczegółowej analizy zachowania elementu jednocześnie skręcanego i ścinanego w całym za kresie obciążenia. Omówiono również założenia teorii MCFT, która stanowi podstawę teoretyczną modelu Rahala i Collinsa. Przedstawiono własną propozycję metody obliczania szerokości rys w elementach żelbetowych poddanych jednoczesnemu działaniu momentu skręcającego i siły poprzecznej. Metoda oparta jest na modelu Rahala i Collinsa.This paper concerns the phenomenon of cracking in reinforced concrete elements subjected to combined torsion and shear. The theoretical model developed by Rahal and Collins is described in de tail. This model is the only one which is capable of predicting the full response (e.g.: steel and concrete strains, deformations, curvatures) rectangular reinforced concrete sections subjected to combined torsion and shear throughout their post cracking loading history. The assumptions of Modified Compression Field Theory are also described because the model of Rahal and Collins is based on this theory. It also contains a concept of the new method which is capable of determining the width of cracks in reinforced concrete elements subjected to combined torque moment and shear force. The method is based on the model suggested by Rahal and Collins
Hazard analysis on homogeneous road sections
Przedstawiono założenia do oceny zagrożeń w ruchu drogowym z wykorzystaniem inspekcji bezpieczeństwa ruchu drogowego. Opisano wyniki modelowania zagrożeń w ruchu drogowym na drogach krajowych. Wskazano modele opisujące wpływ wybranych czynników na gęstość ofiar śmiertelnych i liczbę ofiar śmiertelnych na drogach krajowych.The paper presents assumptions for the assessment of traffic using road safety audit. The results of modeling hazards in road traffic on national roads were described. The models describing the impact of selected factors on the density of deaths and the number of deaths on the roads were defined
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