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During menopause, the risk of depression is 2–5 times greater than pre- or post-menopause. To assess the risk of depression amongst menopausal women in 2006, compared with 2021 (i.e., during the COVID-19 pandemic), we recruited female volunteers at least 40 years old to complete the menopause rating scale (MRS), the Blatt–Kupperman menopausal index (BKMI), and the Beck depression inventory. Compared with 2006, in 2021, the number of participants who experienced mild, moderate, and severe menopausal symptoms rose by 8%, 1.9%, and 3.2%, respectively. Moreover, the frequency of using hormone replacement therapy rose by 5.1%, feelings of mistrust by 16%, feelings of guilt by 11%, disposition to cry by 25%, mood swings by 12%, and suicidal ideation by 9%, whilst the average body weight and body mass index fell by 5.1 kg and 2.3%, respectively. In 2006 and 2021, 46.3% and 59.3% of participants experienced moderate depression, whereas 3.0% and 5.2% experienced severe depression. The number of participants who denied needing support during menopause decreased by 14.6%, whereas the demand for support from husbands and friends increased by 18.3% and 9.8%, respectively. In 2021, the number of participants who experienced menopausal symptoms, a loss of trust, self-blame, a tendency to cry, mood swings, suicidal ideation, and anxiety also increased compared with 2006, whilst the number of participants without depressive symptoms decreased, but with suspected mild or severe depression increased. Last, menopausal complaints caused an increase in depressive mood in 2021, as evaluated using the BKMI and MRS.

Fossil plant macroremains preserved in laminated diatomites from Łysa Góra near Rębiszów, Lower Silesia, have been documented for the first time. The fossil assemblage consists mostly of leaves, but fruits, seeds and sporadic flowers also occur. Forty-three identified taxa represent nineteen plant families: Aceraceae, Berberidaceae, Betulaceae, Cornaceae, Cupressaceae, Elaeocarpaceae, Ericaceae, Fagaceae, Lauraceae, ?Leguminosae, ?Meliaceae, Magnoliaceae, Pinaceae, Rhamnaceae, Rosaceae, Salicaceae, Tilioideae, Ulmaceae, Vitaceae, and one incertae sedis. The prevalence of entire margined leaves, mostly represented by Majanthemophyllum basinerve and Daphnogene cinnamomifolia, and a significant presence of Calocedrus suleticensis and Liriodendron haueri, are characteristic features of the Rębiszów flora. The composition of the plant assemblage points to a mesophytic forest with some riparian elements and suggests favourable, warm climatic conditions. Radiometrically dated basalts overlying fossiliferous layers and composition of palynoflora suggest at least Chattian (late Oligocene) age. The lithology and floristic composition link the Rębiszów flora with the so-called volcanic floras of the Nerchau-Flörsheim or Kleinsaubernitz floristic complex (Oligocene) from Germany and Czech Republic with Suletice-Berand flora being especially close.

Introduction: Menopause is a physiological period in a woman’s life, but it is often accompanied by symptoms that affect mental well-being and general health, including a tendency for depression. Aim of the study: To evaluate the predisposition to the symptoms of depression in women from Poland, Belarus, Belgium, and Greece. Material and methods: the method of diagnostic survey was used, and the research tools were: The Menopause Rating Scale, the Kupperman Index, Beck Depression Inventory, and a self-made survey questionnaire. Results: Hormone replacement therapy (HRT) was used by 15.8% of Polish, 19% of Belgian, 14.3% of Belarusian, and 15.2% of Greek women patients. The mean value of the Kupperman Index (range 0–63) in Poland was 14.8 ± 8.6, in Belgium—15.5 ± 6.6, Belarus—14.0 ± 9.4, and Greece—10.8 ± 6.5, while the total measure of Menopause Rating Scale (MRS) (range 0–44) was 12.2 ± 7.6 in Poland, 13.8 ± 6.5 in Belgium, 10.8 ± 8.0 in Belarus and 12.9 ± 7.4 in Greece. The severity of mental distress followed a similar pattern across all countries (slightly stronger than mild). The results for somatic complaints were similar, whereas the level of sexual issues varied, with the highest in Belgium and the lowest in Belarus. The mildest symptoms of menopause were experienced by Belarusian women and the most severe by Belgian women. The severity of depression, according to the Beck Depression Inventory (range 0–63), was as follows: Poland 10.5 ± 7.9; Belgium—11.1 ± 5.7; Belarus—13.7 ± 5.7; Greece—11.8 ± 6.6. Conclusions: The differences between the development of perimenopausal-related symptoms across countries were statistically significant. The incidence and severity of depression showed statistically significant differences between the countries studied—the highest was in Belarus and the lowest in Poland. Depression levels were not differentiated by subjects’ age or the use of hormone therapy but by subjects’ education. In Poland and Belarus, increased menopausal pain measured by the Kupperman Index altered levels of depression; in Belgium, there were no such correlations, and in Greece, the correlation was statistically significant, but its strength was negligible. A clearer correlation of the effects of development in menopausal symptoms on the level of depression was shown when measured with the MRS scale—in Greece and Belgium, the correlation was relatively weak, but in Poland and Belarus, it was relatively high.

Ionization of atoms and molecules in laser fields can lead to various interesting interference structures in the photoelectron spectrum. For the case of a superintense extreme ultraviolet laser pulse, we identify a novel petal-like interference structure in the electron momentum distribution along the direction of the laser field propagation. We show that this structure is quite general and can be attributed to the Fresnel diffraction of the electronic wave packet by the nucleus. Our results are demonstrated by numerically solving the time-dependent Schr\"odinger equation of the atomic hydrogen beyond the dipole approximation. By building an analytical model, we find that the electron displacement determines the aforementioned interference pattern. In addition, we establish the physical picture of laser-induced electron Fresnel diffraction which is reinforced by both quantum and semiclassical models.

In this paper, we have examined the influence of electroplated gold thickness on the thermal and electro-optical properties of mid-IR AlInAs/InGaAs, InP QCLs. The experimental results show a significant reduction of the temperature of QCL active region (AR) with increasing gold layer thickness. For QCLs with 5.0 μm gold thickness, we observed a 50% reduction of the active region temperature. An improvement of key electro-optical parameters, that is, threshold current density and maximum emitted power for structures with thick gold, was observed. The results of micro-Raman characterization show that the electroplated gold layer introduces only moderate compressive strain in top InP cladding, which is well below the critical value for the creation of misfit dislocations.

The aim of this article is to present “business interpreting” as such and to contrast it with conference and community interpreting. The article also discusses various roles interpreters assume in business setting and gives examples of real-life situations where it might be difficult to unambiguously decide what should be expected from an interpreter. A number of questions for further research is also asked.

The formation of quantum vortices in photodetachment by a sequence of left- and right-handed circularly polarized laser pulses in various configurations is analyzed using either the strong-field approximation or numerical solution of the time-dependent Schr\"odinger equation. Two types of pulse sequences are considered: reducible and irreducible. While the former can be decomposed into series of consecutive and identical (irreducible) subtrains of pulses, the latter cannot be decomposed in that way. As we show, the vortex pattern in the probability amplitude of photodetachment is fully determined by the irreducible pulse configuration. Additional repetitions of an irreducible train create, in the three-dimensional momentum space, nonvortex nodal surfaces, the position of which is estimated. The conditions for the experimental observation of quantum vortices are also determined.

The human skeleton is truly amazing. It is a moving frame that protects soft tissues and organs, while simultaneously storing minerals and producing blood cells and immune cells. Bones also have an amazing ability to rebuild and repair themselves. There is no need to worry much if you break a bone because, with the support of your doctors and therapists, the bone should heal itself. Bones have a flexible structure that serves as the scaffolding for the minerals that create a strong and stable skeleton. Unfortunately, bone strength may decrease with age or due to food or hormonal deficiencies. When you experience pain, swelling, or bruising following a fall, you should go to the doctor to see if you have a bone fracture. But do not worry—remember that bones can repair themselves! Have you ever wondered how bone healing happens? You can find the answers in this article.

Osteosarcoma (OS) is a bone tumour affecting adolescents and elderly people. Unfortunately, basic treatment methods are still underdeveloped, which has a high impact on the poor survivability of the patients. Studies designed to understand the underlying mechanisms of osteosarcoma development, as well as preclinical investigations aimed at establishing novel therapeutic strategies, rely significantly upon in vitro models, which apply well-established cell lines such as U-2 OS, Saos-2 and MG-63. In this study, the expression of chosen markers associated with tumour progression, metastasis and survival were identified using RT-qPCR. Levels of several onco-miRs (miR-21-5p, miR-124-3p, miR-223-3p and miR-320a-3p) and long non-coding RNA MEG3 were established. The mRNA expression of bone morphogenetic proteins (BMPs), including BMP-2, BMP-3, BMP-4, BMP-6, BMP-7, as well as their receptors: BMPR-IA, BMPR-IB and BMPR-II was also determined. Other tested markers included metalloproteinases, i.e., MMP-7 and MMP-14 and survivin (BIRC5), C-MYC, as well as CYCLIN D (CCND1). The analysis included comparing obtained profiles with transcript levels established for the osteogenic HeLa cell line and human adipose-derived stromal cells (hASCs). The tested OS cell lines were characterised by a cancer-related phenotype, such as increased expression of mRNA for BMP-7, as well as MMP-7 and MMP-14. Osteosarcoma cells differ considerably in miR-21-5p and miR-124-3p levels, which can be related to uncontrolled tumour growth. The comprehensive examination of osteosarcoma transcriptome profiles may facilitate the selection of appropriate cell models for preclinical investigations aimed at the development of new strategies for OS treatment.

Generation of electron vortices in photodetachment of ${\mathrm{H}}^{\ensuremath{-}}$ by circularly polarized laser pulses is analyzed by means of strong-field approximation and by numerically solving the time-dependent Schr\"odinger equation. A very good agreement is shown for the magnitude and the phase of the probability amplitude of photodetachment from both approaches. We demonstrate that spiral-like patterns in the probability amplitude of detachment, observed for a pair of counter-rotating circularly polarized laser pulses, cannot be associated with nonvanishing topological charge vortices. The latter can be generated, on the other hand, by a circularly polarized laser pulse or a sequence of such pulses with corotating polarizations. Such interpretation of our results follows from the hydrodynamical formulation of quantum mechanics and its generalization to arbitrary parametric spaces.

Generation of electron vortices in photodetachment driven by linearly polarized laser pulses is demonstrated, both within the strong-field approximation and by numerically solving the time-dependent Schr\"odinger equation. The sensitivity of the resulting vortex patterns in the momentum distributions of photoelectrons to the laser pulse parameters (including the pulse duration, its intensity, and the carrier-envelope phase) is analyzed. It is shown that, for a nonzero carrier-envelope phase of the driving pulse, vortex structures in the probability amplitude of detachment occur, similar to von K\'arm\'an vortex streets in fluid mechanics. In addition, hexagonal regions of high probability (honeycomb patterns) are observed, with vortex-antivortex pairs located at their vertices.

Generation of propagating electron vortex states in ionization of ${\mathrm{H}}^{\ensuremath{-}}$ by short, circularly polarized laser pulses is studied within the strong-field approximation. The latter, being particularly suitable for treating negative ions, is shown to be gauge independent for an $s$-electron system like ${\mathrm{H}}^{\ensuremath{-}}$. Most importantly, it is demonstrated that the orbital angular momentum from the laser field can be efficiently transferred to photoelectrons, thus resulting in high orbital angular momenta electron vortex states. The conditions for this to happen are formulated and visualized with the help of coarse-grained probability distributions of photoelectrons, which are calculated by Monte Carlo method.

The non-Hermitian Floquet theory is applied to systematically calculate both the ac-Stark shift $\ensuremath{\delta}$ and the decay rate $\ensuremath{\gamma}$ for hydrogen atoms and hydrogen molecular ions, when placed in a high-frequency laser field with an intensity ranging from the perturbation to the stabilization region. This allows us to trace the appearance of dynamical interference in ionization. We find that both the stabilization and the dynamical interference are easier to achieve at a frequency close to the ionization threshold. For the molecular case, the effects of nuclear motion are discussed based on the Born-Oppenheimer approximation. Although the dynamical interference condition $\ensuremath{\delta}g\sqrt{\ensuremath{\pi}}\ensuremath{\gamma}$ seems to be satisfied at a low frequency for a fixed-nuclei ${{\mathrm{H}}_{2}}^{+}$ in the perturbation region, the effects of the nuclear motion are shown to destroy the interference patterns in this region. Meanwhile, for the sake of confirmation, the photoelectron energy distributions are calculated by solving the time-dependent Schr\"odinger equation for the parameters where the dynamical interference is predicted by the non-Hermitian Floquet theory.

The aim of this study was to retrospectively compare values of thyroid-stimulating hormone (TSH) in adolescent patients diagnosed with schizophrenia, bipolar disorder, unipolar depression (UNI-DEP), conduct disorders (CD), and hyperkinetic disorders. The research involved 1122 patients (718 women, 64%); aged 12 to 18 hospitalized in the Department of Adolescent Psychiatry, Medical University of Lodz. We analyzed TSH levels in the whole study population and compared it between the above-mentioned subgroups of diagnoses. Mean serum TSH concentration in the studied population (n = 1122) was 2.06 μIU/mL. The values of percentiles were as follows: 2.5th – 0.53 μIU/mL, 10th – 0.89 μIU/mL, 25th – 1.31 μIU/mL, 50th – 1.9 μIU/mL, 75th – 2.6 μIU/mL, 90th – 3.43 μIU/mL, 97.5th – 4.72 μIU/mL. TSH values were negatively correlated with patients’ age (P = .00001). Patients with bipolar depression had higher TSH levels than patients with CD (P = .002). Also, when male and female groups were examined separately we found that female patients with UNI-DEP and bipolar disorder had higher TSH levels than female patients with CD (P = .001; P = .001). Our results confirm that there may be a higher prevalence of thyroid dysfunctions in bipolar and UNI-DEP subgroups among adolescents and that it is worthy to consider some kind of interventions regarding thyroid function in depressed individuals.

Background. Health behaviours are very important factors of human life. Currently, as the number of vaccinated children in Poland and throughout Europe is decreasing, parents’ health behaviours may affect the frequency of vaccinations. The aim of this study was to assess the impact of parents’ preferred health behaviours regarding vaccinations.Methods. The study was carried out using a diagnostic survey method with an original questionnaire and the Inventory of Health Behaviours. The study included 300 parents.Results: The level of health behaviours was average in 42.3% of the respondents, low in 33%, and high in 24.7%. Convictions about immunity after contracting a disease, the need to vaccinate for all diseases, the vaccination system, the quality of the vaccines used in Poland, the universal obligation to vaccinate, and the admission of unvaccinated children to crèches and kindergartens were not statistically related to health behaviours. Significant differences in health behaviours, mainly the level of normal eating habits (p = 0.038) and positive mental attitude (p = 0.022), were found in relation to views on the toxicity of vaccines. Participants who reported that vaccines can cause autism engaged in a higher level of prophylactic behaviours. Respondents who vaccinated their children with combined vaccines had a significantly higher level of health practices. Significant or near-significant differences in health behaviour levels in various areas were found between those who sought the recommended vaccinations and those who did not.Conclusions: The health behaviour levels of the majority of the respondents were average, and the most frequent category was "positive mental attitude.” Parents who believed in the toxicity of vaccines were more concerned about proper nutrition, had a positive mental attitude, and engaged in a higher level of preventive behaviours and health practices. Parents who did not vaccinate their children had lower levels of normal eating habits. Parents who vaccinated their children with additional vaccines had a higher level of health behaviours, especially in terms of health practices.

BackgroundCurrently, as the number of vaccinated children in Poland and throughout Europe is decreasing. Many factors impact on the rate vaccination and parents’ health behaviours may affect the frequency of vaccinations. The aim of the study was to assess the association of parents’ health behaviors with children’s vaccinations.MethodsA cross-sectional survey was conducted from July 2015 to June 2016 to assess to assess the association of parents’ health behaviors with children’s vaccinations in Białystok city, Poland. We used the the Inventory of Health Behaviours and an original questionnaire including demographic data and questions about vaccination. Three hundred parents were recruited from the Pro Medica Family Medica Center in Bialystok, Poland.ResultsOnly 3.7% of respondents did not vaccinate their children. The level of health behaviours was average in 42.3% of the respondents, low in 33%, and high in 24.7%. Significant differences in health behaviours, mainly the level of normal eating habits (p = 0.038) and positive mental attitude (p = 0.022), were found in relation to views on the toxicity of vaccines. Participants who reported that vaccines can cause autism engaged in a higher level of prophylactic behaviours. Respondents who vaccinated their children with combined vaccines had a significantly higher level of health practices.ConclusionsParents preferred health behaviours did not effect on children vaccination.Parents who believed in the toxicity of vaccines were more concerned about proper nutrition, had a positive mental attitude, and engaged in a higher level of preventive behaviours and health practices. Parents who did not vaccinate their children had lower levels of normal eating habits. Parents who vaccinated their children with combined vaccines had a higher level of health behaviours, especially in terms of health practices.

HHG of up to 70th order utilizing graphene subjected to bicircular electromagnetic fields of terahertz frequencies was investigated. A momentum-resolved harmonic spectrum and induced electron current densities were obtained and analyzed.

Momentum distributions of electron-positron pairs created from the vacuum by an oscillating in time electric field are calculated in the framework of quantum field theory. A pronounced enhancement of those distributions is observed as the frequency of the electric field passes across the one-photon threshold. Below that threshold the pairs preferentially carry a longitudinal momentum, while above the threshold they tend to carry a transverse momentum. Such momentum sharing has an impact on the number of produced pairs: It grows fast with increasing the field frequency below the threshold but it saturates at a roughly constant value above it. On the other hand, at the fixed frequency above the one-photon threshold, the number of pairs scales quadratically with the field strength. This typically perturbative scaling holds even for large electric fields. Thus, the validity of the perturbation theory is extended here to processes which result in creation of particles with substantial transverse momenta., 8 pages, 8 figures

During adolescence, related to the crisis of identity, attempts to separate from the family and rebellion against the reality result in the youth to be particularly susceptible to the impact of peers. Identification with the group is most often based on common interests, one of which being music. The aim of the pilot study was to assess the relationship of autodestructive and antisocial behaviour and music preferences of girls subject to inpatient stay due to mental problems. Material and methods: Own questionnaire was used concerning music preferences, consisting of the following genres: metal, rock, pop, jazz, hip-hop, reggae, film music, sung poetry, electronic music. The studied group comprised of 26 girls diagnosed with mood disorders, neurotic, stress-related and somatoform disorders, eating disorders and behavioural and emotional disorders according to ICD-10. Exclusion criteria were the remaining diagnostic categories, especially active psychotic process and mental retardation as well as lack of understanding of the questionnaire questions or not being familiar with basic types of music. Among the patients aged 13–18 subject to inpatient stay at the Department of Adolescent Psychiatry in Łódź in the period 2013–2014 and consented to the study, the incidence of attempted suicide, inflicting self-harm, alcohol abuse, taking psychoactive substances and the presence of antisocial disorders were assessed. Questionnaire verification was carried out in a group of 30 people tested with a test–retest method with a two-week break; reliability was obtained: 0.89–1. Analysis was carried out with the use of Statistica 9.1 programme. Results: Among the teenage girls subject to inpatient stay, music preferences were not related in a statistically significant manner (p > 0.05) with a greater incidence of attempted suicide, inflicting self-harm, alcohol abuse and contact with psychoactive substances, nor the psychiatric diagnosis. Conclusions: Girls subject to inpatient stay at the mental ward most often preferred hip-hop. No significant relationship of the preference over a particular music genre and the number of autodestructive and risky behaviour was observed; only tendencies for more frequent selection of particular genres of music were visible.

Dynamical Sauter-Schwinger mechanism of pair creation by a time-dependent electric field comprising of $N_{\rm rep}$ identical pulses is analyzed within the framework of the spinor and scalar quantum electrodynamics. For linearly polarized pulses, both theories predict that a single eigenmode of the matter wave follows the dynamics of a two-level system. This dynamics, however, is either governed by a Hermitian (for spin 1/2 particles) or pseudo-Hermitian (for spin 0 particles) Hamiltonian. Essentially, both theories lead to a Fraunhofer-type enhancement of the momentum distributions of created pairs. While in the fermionic case the enhancement is never perfect and it deteriorates with increasing the number of pulses in a train $N_{\rm rep}$, in the bosonic case we observe the opposite. More specifically, it is at exceptional points where the spectra of bosonic pairs scale exactly as $N_{\rm rep}^2$, and this scaling is even enhanced with increasing the number of pulses in a train., Comment: 30 pages, 8 figures

The Sauter-Schwinger process of electron-positron pair creation from vacuum, driven by a sequence of time-dependent electric-field pulses, is studied in the framework of quantum-field theoretical approach. As demonstrated by our numerical results, the probability distributions of produced pairs exhibit intra- and inter-pulse interference structures. We show that such structures can be observed beyond the regime of applicability of the WKB theory, which was the focus of earlier investigations. Going beyond these developments, we perform the analysis of the time-evolution operator for an arbitrary eigenmode of the fermionic field. This shows that a perfect coherent enhancement of the inter-pulse peaks can never be reached. A nearly perfect coherence, on the other hand, is due to nonadiabatic transitions at avoided crossings of the phases defining the unitary time evolution. This analysis allows us to determine the conditions under which the nearly perfect coherence is lost., Comment: 13 pages, 6 figures

The domain of validity of the Coulomb-Corrected Strong Field Approximation (CCSFA) is going to be analyzed in relation to the semi-classical dynamics of electrons during ionization of hydrogen-like targets. Our analysis is limited to ionization driven by Ti-sapphire laser pulses with intensities up to roughly 10$^{14}$ Wcm$^{-2}$. For such parameters, the effects related to radiation pressure are small and the laser field can be described in the dipole approximation. By applying the Magnus expansion for the exact retarded electron propagator we obtain an {\it effective action} which is free of Coulomb singularities and branch points when the complex-time trajectories are used. Furthermore, we show that the classical action is exactly recovered as the asymptotic limit of its effective counterpart. The applicability of such limit is also discussed., 12 pages, 2 figures; lecture delivered at the 27th International Laser Physics Workshop, Nottingham, UK, July 16-20, 2018

The generation of electron vortex states in ionization by intense and short laser pulses is analyzed under the scope of the lowest-order Born approximation. For near infrared laser fields and nonrelativistic intensities of the order of $10^{16}$~W/cm$^2$, we show that one has to modify the nonrelativistic treatment of ionization by accounting for recoil and mass relativistic corrections. By using the corrected quasi-relativistic theory, the requirements for the observation of electron vortex states with non-negligible probability and large topological charge are determined., Comment: 15 pages, 9 figures

Photoionization of positive ions by a train of intense, short laser pulses is investigated within the relativistic strong field approximation, using the velocity gauge. The formation of broad peak structures in the high-energy domain of photoelectrons is observed and interpreted. The emergence of coherent photoelectron energy combs within these structures is demonstrated, and it is interpreted as the consequence of the Fraunhofer-type interference/diffraction of probability amplitudes of ionization from individual pulses comprising the train. Extensions to the coherent angular combs are also studied, and effects related to the radiation pressure are presented.

Konkurs der Unternehmen ist in der modernen Wirtschaft nichts Ungewöhnliches. Es ist ein Prozess, der mit der Funktionsweise der Wirtschaft nach marktwirtschaftlichen Grundsätzen stark verbunden ist. Die Durchführung des Insolvenzverfahrens wird gesetzlich geregelt und durch das Gesetz vom 28. Februar 2003 festgelegt – Konkurs – und Sanierungsrecht, Gesetzblatt. 2003 No. 60, Pos. 535. Der Konkurs bedeutet nicht mit dem Gewerbe auf zuhören. Kraft des Gerichtsurteils kann es mit dem Vertrag verkündet werden. Das heißt, der Schuldner kann zu einem gewissen Grad das Gewerbe weiterhin treiben und nach vorherigen Vereinbarungen seine Gläubiger abzahlen. Ansonsten umfasst der Konkurs die Liquidation des Schuldnervermögens. Ziel des Artikels ist es, die Besonderheiten des Konkurses der Unternehmen in Polen in den Jahren 2003–2013 zu präsentieren. Statistische Analyse der insolventen Unternehmen in Polen durchzuführen und deren Übereinstimmung mit den grundlegenden makroökonomischen Faktoren zu zeigen.

The generation of electron vortex states of large topological charge in high-energy ionization is demonstrated. To this end, the fully relativistic Dirac theory is used to determine the conditions to obtain such states.

Ionization of positive ions by relativistically-intense short laser pulses is analyzed in the framework of relativistic strong-field theory. We observe the appearance of broad interference-free patterns in the high-energy portion of the photoelectron spectra, which extend over hundreds of driving photon energies. These structures can be controlled by changing parameters of the driving laser field. As we also demonstrate, the electrons comprising these broad structures can form pulses of attosecond duration. While we present the fully numerical results for laser field intensities below 10 20 W=cm 2 , we also introduce the saddle point approximation to treat photoionization at larger intensities. In addition, the conditions enabling generation of ultrashort electron pulses are studied.

Electron-hole creation in single-layer intrinsic graphene interacting with bicircular laser fields is investigated. Due to the linear dispersion relation near the degeneracy points, the electron and hole dynamics are treated according to the Dirac theory, i.e., it is assumed that the charge carriers behave as ultrarelativistic massless fermions. Of special interest is their dynamical mass generation induced by a THz electromagnetic radiation. The harmonic response from graphene and electron currents induced by the bicircular laser field are also analyzed.

The nonlinear Compton scattering by a linearly polarized laser pulse of finite duration is analyzed, with a focus on the spin effects of target electrons. We show that, although the Compton scattering accompanied by the electron no-spin flip is dominant, for some energy regions of Compton photons their emission is dominated by the process leading to the electron spin flip. This feature is observed for different pulse durations, and can be treated as a signature of quantum behavior. Similar conclusions are reached when analyzing the scattered electron energy spectra. This time, the sensitivity of spin effects to the carrier-envelope phase of the driving pulse is demonstrated. The possibility of electron acceleration by means of Compton scattering is also discussed.

Background: The concentration and specific activity of N-acetyl-β-hexosaminidase (HEX) in palatine tonsils with chronic tonsillitis and tonsillar hypertrophy give insight in tonsillar tissue remodeling and constitute a potential marker for diagnosis and treatment of chronic tonsillitis and tonsillar hypertrophy. Aim: Determining the concentration and specific activity of N-acetyl-β-hexosaminidase in palatine tonsils with hypertrophy and chronic tonsillitis. Methods: HEX activity was analyzed by the method of Marciniak et al. with p-nitrophenyl N-acetyl-β-glucosaminepyranoside as a substrate. Results: The concentration and specific activity of HEX in palatine tonsils in patients with tonsillar hypertrophy and chronic tonsillitis both in childhood and adulthood significantly increase in comparison to healthy individuals. Conclusions: Our data demonstrate the presence of HEX in palatine tonsils and indicate on significant increase of its concentration and specific activity. Based on content and specific HEX activity we suggest that tonsils with hypertrophy and chronic tonsillitis should be treated as identical unit irrespectively of age.

Ionization by relativistically intense short laser pulses is studied in the framework of strong-field quantum electrodynamics. Distinctive patterns are found in the energy probability distributions of photoelectrons. Except of the already observed patterns, which were studied in Phys. Rev. A {\bf 94}, 013402 (2016), we discover an additional interference-free smooth supercontinuum in the high-energy portion of the spectrum, reaching tens of kiloelectronovolts. As we show, the latter is sensitive to the driving field intensity and it can be detected in a narrow polar-angular window. Once these high-energy electrons are collected, they can form solitary attosecond pulses. This is particularly important in light of various applications of attosecond electron beams such as in ultrafast electron diffraction and crystallography, or in time-resolved electron microscopy of physical, chemical, and biological processes., Comment: 13 pages, 9 figures

Production of electron-positron pairs in the collision of a high-energy photon with a high-intensity few-cycle laser pulse is studied. By utilizing the frameworks of laser-dressed spinor and scalar quantum electrodynamics, a comparison between the production of pairs of Dirac and Klein-Gordon particles is drawn. Positron energy spectra and angular distributions are presented for various laser parameters. We identify conditions under which predictions from Klein-Gordon theory either closely resemble or largely differ from those of the proper Dirac theory. In particular, we address the question to which extent the relevance of spin effects is influenced by the short duration of the laser pulse., Comment: 11 pages, 7 figures

We consider the process of electron-positron pair creation by an impact of ultra-intense laser beam on a highly relativistic nucleus, with an exact account for its finite mass. It is shown that the probability rates of pair production increase tremendously due to the nuclear recoil. Numerical calculations also show the existence of very narrow resonances in differential probability rates of pair production, which are recognized to be Oleinik resonances, as they originate from poles of the photon propagator. Using our exact treatment of the colliding nucleus, we analyze also the effect of dressing it by the laser field on the process of pair creation.

Ionization of hydrogen-like ions driven by intense, short, and circularly-polarized laser pulses is considered under the scope of the relativistic strong-field approximation. We show that the energy spectra of photoelectrons can exhibit two types of structures, i.e., interference-dominated or interference-free ones. These structures are analyzed in connection to the time-dependent ponderomotive energy of electrons in the laser field. A possibility of synthesis of ultrashort single-electron pulses from those structures is also investigated.