Multiparameter Estimation Perspective on Non-Hermitian Singularity-Enhanced Sensing.

Describing the evolution of quantum systems by means of non-Hermitian generators opens a new avenue to explore the dynamical properties naturally emerging in such a picture, e.g. operation at the so-called exceptional points, preservation of parity-time symmetry, or capitalizing on the singular behavior of the dynamics.

Quantum metrology with imperfect measurements.

The impact of measurement imperfections on quantum metrology protocols has not been approached in a systematic manner so far. In this work, we tackle this issue by generalising firstly the notion of quantum Fisher information to account for noisy detection, and propose tractable methods allowing for its approximate evaluation. We then show that in canonical scenarios involving N probes with local measurements undergoing readout noise, the optimal sensitivity depends crucially on the control operations allowed to counterbalance the measurement imperfections-with global control operations, the ideal sensitivity (e.

Fundamental Limits in Bayesian Thermometry and Attainability via Adaptive Strategies.

We investigate the limits of thermometry using quantum probes at thermal equilibrium within the Bayesian approach. We consider the possibility of engineering interactions between the probes in order to enhance their sensitivity, as well as feedback during the measurement process, i.e.

Bell Nonlocality Is Not Sufficient for the Security of Standard Device-Independent Quantum Key Distribution Protocols.

Device-independent quantum key distribution is a secure quantum cryptographic paradigm that allows two honest users to establish a secret key, while putting minimal trust in their devices. Most of the existing protocols have the following structure: first, a bipartite nonlocal quantum state is distributed between the honest users, who perform local projective measurements to establish nonlocal correlations. Then, they announce the implemented measurements and extract a secure key by postprocessing their measurement outcomes.

Signal Tracking Beyond the Time Resolution of an Atomic Sensor by Kalman Filtering.

We study causal waveform estimation (tracking) of time-varying signals in a paradigmatic atomic sensor, an alkali vapor monitored by Faraday rotation probing. We use Kalman filtering, which optimally tracks known linear Gaussian stochastic processes, to estimate stochastic input signals that we generate by optical pumping. Comparing the known input to the estimates, we confirm the accuracy of the atomic statistical model and the reliability of the Kalman filter, allowing recovery of waveform details far briefer than the sensor's intrinsic time resolution.

Ultimate Precision Limits for Noisy Frequency Estimation.

Quantum metrology protocols allow us to surpass precision limits typical to classical statistics. However, in recent years, no-go theorems have been formulated, which state that typical forms of uncorrelated noise can constrain the quantum enhancement to a constant factor and, thus, bound the error to the standard asymptotic scaling. In particular, that is the case of time-homogeneous (Lindbladian) dephasing and, more generally, all semigroup dynamics that include phase covariant terms, which commute with the system Hamiltonian.

Noisy metrology beyond the standard quantum limit.

Parameter estimation is of fundamental importance in areas from atomic spectroscopy and atomic clocks to gravitational wave detection. Entangled probes provide a significant precision gain over classical strategies in the absence of noise. However, recent results seem to indicate that any small amount of realistic noise restricts the advantage of quantum strategies to an improvement by at most a multiplicative constant.

The elusive Heisenberg limit in quantum-enhanced metrology.

Quantum precision enhancement is of fundamental importance for the development of advanced metrological optical experiments, such as gravitational wave detection and frequency calibration with atomic clocks. Precision in these experiments is strongly limited by the 1/√N shot noise factor with N being the number of probes (photons, atoms) employed in the experiment. Quantum theory provides tools to overcome the bound by using entangled probes.

[Impacts of climate change on infectious diseases].

Climate warming may have significant impacts on human health, including changes in the distribution and seasonality of vector-borne diseases. We discuss the consequences of climate change on infectious diseases. Effects of transmission of the imported tropical diseases in Europe are discussed.

[Nonspecific adhesion of Staphylococcus aureus strains to solid surfaces].

Autoagregating strains of bacteria are characterised by high surface hydrophobicity, which determines their ability to adhesion. An assessment was done of non-specific adhesion to solid surfaces of S. aureus strains isolated from blood, pus and nasopharynx of hospitalised people.

[Protozoa as reservoirs for human bacterial pathogens].

The ability of bacterial pathogens to survive within the human host cells results from their evolutional adaptation of which the most important stage could be the development of parasitic relations between bacteria and free-living protozoa. This paper shows the bacterial species, pathogenic for man, surviving in protozoans cells.

Antibiotic resistance and phage types of faecal Klebsiella isolated from healthy zoo apes.

The isolated species of Klebsiella were characterized by biotyping and phage typing methods. The majority of strains were resistant to certain examined drugs. For epidemiological reasons these strains can be potentially dangerous to the population of zoo animals.

Effect of some quaternary benzylammonium salts on physiology of yeast.

In order to determine the biological activity of eight compounds belonging to a group of quaternary ammonium salts, their influence on the active methionine transport, the integrity of cell membranes, respiration, and viability of Saccharomyces cerevisiae and some other yeast species has been investigated. The earliest effect observed during ammonium salts action on yeast cells is an immediate methionine transport abolishment followed by its fast leakage, which indicates increasing cell membrane degradation. Gradual decline of other biological functions such as respiration and viability is thus a result of disintegration and lack of tightness of the cell membranes.

pif mutation blocks recombination between mitochondrial rho+ and rho- genomes having tandemly arrayed repeat units in Saccharomyces cerevisiae.

Three allelic nuclear mutants affected in the recombination of mtDNA have been characterized in Saccharomyces cerevisiae and assigned to the PIF locus. In the mutants, the general recombination measured by the recombination frequency between linked or unlinked alleles is normal. However, the pif mutations prevent the integration into the rho+ genome of the markers (oli1, oli2, diu1, ery, oxi1, oxi2) of those rho- genomes that have tandemly arrayed repeat units.

Light effects in yeast: relation between the respiratory deficiency and light sensitivity in yeast.

Visible light of 5,000 lux intensity has been shown to photokill yeast cells at 12 degrees C. In the present report some of isogenic respiratory deficient mit- and nuclear mutants were compared for their sensitivity to light. No close correlation between the cytochromes spectra and light resistance was observed.

The lethal effects of some onolophosphate insecticides on yeast Saccharomyces cerevisiae.

Thre enolophosphate insecticides (chlorphenvinphos: 0-/-/2',4'-dichlorophenyl/-2-chlorovinyl/diethyl phosphate, bromphenvinphos: 0-/1-/2',4'-dichlorophenyl/-2-bromovinyl/diethyl phosphate, mebromvinphos: 0-/1-/2',4'-dichlorophenyl/-2-bromovinyl/dimethyl phosphate) have been tested for their biological activity in baker's yeast. The results indicate that the chemicals exert an immediate hibitory effect on amino acid transport system, respiration, fermentation and ell growth. Consequently the effect of precipitous cell death also occurred.

Comparison of some Shigella flexneri (Escherichia coli) hybrids in cross agglutination and agglutinin absorption tests.

Antigenic structure of Lac+ hybrids selected from Escherichia coli x Shigella flexneri crosses was compared in the cross agglutination and absorption tests. Identity of the hybrids from the recipients of serotype 2a and variant Y was proved, as well as from serotypes 1b and 4b. The latter hybrids were coupled with Shigella flexneri strains 3a, 3b and 3c.

Respiratory mutation and galactose metabolism in yeast Saccharomyces cerevisiae.

Restriction in growth on galactose as unique source of energy due to respiratory deficiency resulting from mutation in a gene gal probably different from gal 3 is described.

[Immunologic properties of various cell fractions of a wild strain and a mutant strain of Saccharomyces cerevisiae Hansen].

Some fractions of the Saccharomyces cerevisiae cell wall have been prepared by the action of Helix pomatia juice on intact cells. Immunosera were obtained by injecting rabbits with these fractions. Immunofluorescence reactions, obtained with these sera, show that some fractions of mannopeptides when extracted from a "smooth-colony" mutant strain, have lost antigenic determinants.

Comparative serologic analysis of Lac+ recombinants of serotypes 2a, 2b, 5a and variant Y of Shigella flexneri.

The serologic structure of Lac+ recombinants of 2a, 2b, 5a and var. Y serotypes of Sh. flexneri was compared.