Evanescent Gravitational Waves

We describe the properties of evanescent gravitational waves (EGWs)---wave solutions of Einstein equations which decay exponentially in some direction while propagating in another. Evanescent waves are well-known in acoustics and optics and have recently received much attention due to their extraordinary properties such as their transverse spin and spin-momentum locking. We show that EGWs possess similarly remarkable properties, carrying transverse spin angular momenta and driving freely falling test masses along in elliptical trajectories. Hence, test masses on a plane transverse to the direction of propagation exhibit correlated vector and scalar-like deformation---correlations which can be used to distinguish it from modified gravity. We demonstrate that EGWs are present and dominant in the vicinity of sub-wavelength sources such as orbiting binaries.Comment: 13 pages, movie link https://youtu.be/DB7mHGqsrL

OVERVIEW OF 2018 AMENDMENTS TO THE ACT ON ORGANIZING AND RUNNING CULTURAL ACTIVITY AND THE ACT ON MUSEUMS

The year 2018 did not yield any breakthrough amendments to the Act on Museums. Those adopted were essentially meant to either adjust or complement the existing acts, and were adopted as the consequence of the amendments to other laws. However, the Act on Organizing and Running Cultural Activity, which actually stands as the systemic reference, particularly when it comes to museums operating as cultural institutions, was amended in 2018 to a greater extent. The widest range of the above amendments related to the organizational aspects of the operation of Polish cultural institutions. Firstly, the option of establishing cultural institutions with their seat on the territory of Poland was introduced; this on the grounds of contracts concluded by ministers and managers of central government offices with the organizations active within the area of the protection of national heritage and established in compliance with foreign law (Amendment of 12 April 2018 to the Law on Organizing and Running Cultural Activity). Additionally, the provisions defining competition for the appointment of the director of a cultural institution in compliance with the Amendment of 6 December 2018 to the above Act were substantially extended. The adjusting character in this context can be seen in the amendment to Article 16.4.3 of the Act on Organizing and Running Cultural Activity resulting from the new provisions on the representative trade union organization in the Trade Unions Act, resulting from the Act’s amendment of 5 July 2018. The second scope of the discussed amendments include those of financial character. This can be said both of the amendment of 12 April 2018, related to designated fund and foreseeing allocating them for tasks under state patronage, as well as of the Amendments of 8 April 2017 to the Act on Organizing and Running Cultural Activity in relation to awarding state aid from Norway Funds and EEA. As far as amendments to the Act on Museums in 2018 are concerned, these were reduced to two of very limitedrange ones, so-called terminology amendments of 3 August 2018 within the framework of the regulations introducing the Act on Higher Education and Science, limited to the new phrasing of Articles 10.3.1 and 10.3.2 of the Act on Museums, these dealing currently with postgraduate students, and the amendment of 28 January 2018 consisting in incorporating new Par. 6b in the Act on Museums opening the option for the Medal of the “Guardian of National Memorial Sites”

Geodesic noise and gravitational wave observations by pulsar timing arrays

Signals from millisecond pulsars travel to us on geodesics along the line-of-sight that are affected by the space–time metric. The exact path-geometry and redshifting along the geodesics determine the observed Time-of-Arrival (ToA) of the pulses. The metric is determined by the distribution of dark matter, gas, and stars in the galaxy and, in the final stages of travel, by the distribution of solar system bodies. The inhomogeneous distribution of stellar masses can have a small but significant statistical effect on the ToAs through the perturbation of geodesics. This will result in additional noise in ToA observations that may affect Pulsar Timing Array (PTA) constraints on gravitational waves at very low frequencies. We employ a simple model for the stellar distribution in our galaxy to estimate the scale of both static and dynamic sources of what we term generically “geodesic noise”. We find that geodesic noise has a standard deviation of (10) ns for typical lines-of-sight. This suggests geodesic noise is relevant for estimates of PTA sensitivity and may limit future efforts for detection of gravitational waves by PTAs

All-sky analysis of astrochronometric signals induced by gravitational waves

We introduce a unified spin-weighted formalism to describe both timing and astrometric perturbations induced on astrophysical point sources by gravitational waves using a complex spin field on the sphere. This allows the use of spin-weighted spherical harmonics to analyze “astrochronometric” observables. This approach simplifies the interpretation and simulation of anisotropies induced in the observables by gravitational waves. It also allows a simplified derivation of angular cross-spectra of the observables and their relationship with generalized Hellings-Downs correlation functions. The spin-weighted formalism also allows an explicit connection between correlation components and the spin of gravitational wave polarizations and any presence of chirality. We also calculate expected signal-to-noise ratios for observables to compare the utility of timing and deflection observables

Chiral forces in longitudinally invariant dielectric photonic waveguides

Optical forces can be chiral when they exhibit opposite signs for the two enantiomeric versions of a chiral molecule or particle. Such forces could be eventually used to separate enantiomers, which could find application in numerous disciplines. Here, we analyze numerically the optical chiral forces arising in the basic element of photonic integrated circuitry: a dielectric waveguide with rectangular cross-section. Such waveguides are inherently lossless thus generating chiral forces that are invariant in the longitudinal direction and therefore enable enantiomeric separation over long (cm-scale) distances. Assuming Brownian motion in a liquid environment, we calculate first the force strength and time span needed to perform the separation of chiral nanoparticles as a function of the radii. Then we analyze the chiral forces produced by the fundamental quasi-TE guided mode in a silicon nitride waveguide and show that it can lead to enantiomeric separation via the transverse spin at short wavelengths (405 nm). At longer wavelengths (1310 nm), the proper combination of degenerate quasi-TE and quasi-TM modes would result in a quasi-circularly polarized mode with intrinsic chirality (helicity), leading to chiral gradient forces that also enable the enantiomeric separation of smaller nanoparticles. We report particle tracking simulations where the optical force field produced by a quasi-TE and a quasi-circular mode proved to separate enantiomers under a time span of two seconds. Our results suggest the viability of enantiomeric separation using simple photonic integrated circuits, though different wavelength windows should be selected according to the nanoparticle size.Comment: 19 pages, 6 figure

Optical dipolar chiral sorting forces and their manifestation in evanescent waves and nanofibers

Optical fields can exert forces of chiral nature on molecules and nanoparticles, which would prove extremely valuable in the separation of enantiomers with pharmaceutical applications, yet it is inherently complex, and the varied frameworks used in the literature further complicate the theoretical understanding. This paper unifies existing approaches used to describe dipolar optical forces and introduces a symmetry-based "force basis"consisting of twelve vector fields, each weighted by particle-specific coefficients, for a streamlined description of force patterns. The approach is rigorously applied to evanescent waves and dielectric nanofibers, yielding concise analytical expressions for optical forces. Through this, we identify optimal strategies for enantiomer separation, offering invaluable guidance for future experiments.</p

Sertoli cells modulate testicular vascular network development, structure and function to influence circulating testosterone concentrations in adult male mice

The testicular vasculature forms a complex network, providing oxygenation, micronutrients, and waste clearance from the testis. The vasculature is also instrumental to testis function because it is both the route by which gonadotropins are delivered to the testis and by which T is transported away to target organs. Whether Sertoli cells play a role in regulating the testicular vasculature in postnatal life has never been unequivocally demonstrated. In this study we used models of acute Sertoli cell ablation and acute germ cell ablation to address whether Sertoli cells actively influence vascular structure and function in the adult testis. Our findings suggest that Sertoli cells play a key role in supporting the structure of the testicular vasculature. Ablating Sertoli cells (and germ cells) or germ cells alone results in a similar reduction in testis size, yet only the specific loss of Sertoli cells leads to a reduction in total intratesticular vascular volume, the number of vascular branches, and the numbers of small microvessels; loss of germ cells alone has no effect on the testicular vasculature. These perturbations to the testicular vasculature leads to a reduction in fluid exchange between the vasculature and testicular interstitium, which reduces gonadotropin-stimulated circulating T concentrations, indicative of reduced Leydig cell stimulation and/or reduced secretion of T into the vasculature. These findings describe a new paradigm by which the transport of hormones and other factors into and out of the testis may be influenced by Sertoli cells and highlights these cells as potential targets for enhancing this endocrine relationship. The testicular vasculature forms a complex capillary bed, interdigitating between the seminiferous tubules to provide oxygenation, delivery of micronutrients, and clearance of waste from the testis. Impairment of the testicular vasculature, for example, the reduction in venous drainage observed in cases of varicocele, causes intratesticular hypoxia and germ cell apoptosis (1). The vasculature is also instrumental to the endocrine function of the testis because it is the route by which pituitary gonadotropins are delivered to the testis to support T production and spermatogenesis (2). Conversely, alongside the lymphatic system, the vascular system is important for transport of T to other body systems; a reduced testis and vascular volume is associated with a reduction in circulating T concentrations (3). Our understanding of the mechanisms by which the testis controls local vascular function in adulthood is extremely limited. There is some evidence that testicular mast cells can influence vascular blood flow through release of 5-hydroxytryptamine (4), but perhaps the most well-studied factor influencing testicular vascular function is T. T is a well-established regulator of testicular vasomotion (rhythmical contraction and relaxation of blood vessels, independent of heartbeat) (5, 6) via direct T-mediated activation of the androgen receptor in smooth muscle cells of the testicular vasculature (7). Speculation that Sertoli cells may influence the testicular vasculature is supported by some indirect evidence (5) and in vitro studies (8), but confirmation of a direct role for Sertoli cells in the regulation of the testicular vasculature in vivo has never been demonstrated unequivocally. Recently we developed a unique model system that uses diphtheria toxin to specifically and acutely ablate Sertoli cells from the testis (9, 10). This model has revealed several important, yet previously unknown, roles that Sertoli cells play in neonatal and adult life (reviewed in reference 11). In this study we used models of acute Sertoli cell ablation and acute germ cell ablation, to address whether Sertoli cells actively influence vascular function in the adult testis. Our findings suggest that Sertoli cells play a key role in supporting the structure of the testicular vasculature and describe a new paradigm by which the transport of hormones and other factors into and out of the testis can be influenced by Sertoli cells and highlights these cells as potential targets for enhancing this endocrine relationship

It aspects of museum operations

In the current technological environment, operation of every institution, museum included, requires the use of IT networks, among them the internet. This results from the fact that museums have their respective websites and web addresses. Regardless of the technological aspects, the use of the internet by museums has to bear in mind legal requirements resulting in particular from the Act on Access to Public Information, this including the BIP page, namely that of the Bulletin of Public Information that allows to provide access to this kind of information within the range as defined in the above Act. The requirements of the accessibility of digital websites of public museums taking into account the needs of disabled citizens is specified by the Act on Accessibility of the Websites and Mobile Applications of Public Sector Bodies. Some of the provisions of the Act with respect to websites published before 23 September 2018 will come into force as of 23 September 2020. In the discussed context it also legal provisions related to IT assets that are of importance; these contain computer software and electronic databases. The legal status of these assets is specified in the provisions of the Act on Copyright and Related Rights (see its Arts. 3 and 7) as well as of the Act on Database Protection. Apart from the above, which, however, do not exhaust the whole range of the topic-related issues, it is also important to tackle the question of the digitizing of the assets (collections) that museums have at their disposal, in particular museum objects and images of people that constitute personal rights, which are digitized and disseminated online. Apart from the Act on Museums, particularly its Art. 25a, it is the Act on Copyright and Related Rights as well as the Civil Code that through the general provisions on the protection of personal rights, these also including images of people, give the prescriptive context to the problem.W obecnych uwarunkowaniach technicznych działalność każdej instytucji, także muzeum, wymaga korzystania z sieci informatycznych, w tym z internetu. Jest to związane z posiadaniem przez muzea własnych stron WWW i adresów internetowych. Niezależnie od aspektu technicznego, korzystanie przez muzea z internetu rozpatrywać należy z uwzględnieniem wymogów prawnych wynikających w szczególności z Ustawy o dostępie do informacji publicznej, w tym posiadania przez publiczne muzea strony Biuletynu Informacji Publicznej (BIP), za pośrednictwem której udostępniane są tego rodzaju informacje w zakresie określonym w powyższej ustawie. Wymogi dotyczące dostępności cyfrowej stron internetowych publicznych muzeów, uwzględniające potrzeby osób niepełnosprawnych, określa Ustawa o dostępności cyfrowej stron internetowych i aplikacji mobilnych podmiotów publicznych. Część przepisów tej ustawy, w zakresie stron internetowych opublikowanych przed dniem 23 września 2018 r., wejdzie w życie z dniem 23 września 2020 roku. W omawianym kontekście na uwagę zasługują też unormowania dotyczące dóbr informatycznych istotnych dla działalności muzeów, czyli programów komputerowych i elektronicznych baz danych. Status prawny tych dóbr uregulowany jest w przepisach Ustawy o prawie autorskim i prawach pokrewnych (por. art. 3. i rozdz. 7. tej ustawy) oraz Ustawy o ochronie baz danych. Poza powyższymi aspektami, które nie wyczerpują całego spektrum przedmiotowych zagadnień, na wyróżnienie zasługuje niewątpliwie kwestia digitalizacji dóbr (zbiorów) znajdujących się w dyspozycji muzeów, w szczególności muzealiów oraz stanowiących dobra osobiste wizerunków osób, utrwalonych elektronicznie i rozpowszechnianych z wykorzystaniem internetu. Kontekst normatywny dla tych kwestii stanowią, poza przepisami Ustawy o muzeach, w tym jej art. 25.a, przepisy Ustawy o prawie autorskim i prawach pokrewnych oraz przepisy Kodeksu cywilnego, zawierające ogólne zasady ochrony dóbr osobistych, czyli także wizerunków osób

THE PROBLEMS OF MINORITIES IN MUSEUMS’ ACTIVITIES (LEGAL ASPECTS)

Within the scope of their activity, some museums deal with the protection and dissemination of the cultural heritages of various minority groups. These include both museums which focus their attention on minority problems as such (e.g. museums run by minority churches or denominations), and those museums which deal with such issues to a greater or lesser extent because of their statutory objectives related to the cultural heritage of particular minorities (e.g. ethnographic museums). The provisions of the Act on museums do not include clear regulations with regard to the subject of minorities. Therefore, the provisions are construed with respect to other norms, relevant to the minorities’ activities. From among those provisions, these that deserve particular attention are, above all, provisions specifying the activities of NGOs, including associations and foundations, under which they frequently operate. Secondly, of importance are acts which specifically regulate the basis for how given minorities operate, i.e. especially the Act on national and ethnic minorities and on regional languages, the Act concerning the guarantees of conscience and religion, as well as those acts which determine the State’s approach towards particular churches and denominations. Formally, the extent to which a museum engages in a significant activity regarding a given minority is determined by the basic acts issued by the its administrator, which serve as the basis for its operation. Those include statutes (in the case of museums which are legal persons) or regulations (in the case of other museums). When a museum’s statute provides for such minority activity, its administrator is obliged to provide funding for it, regardless of additional financial support, in particular that coming from grants, and above all the one stipulated in the article 18 of the Act on national and ethnic minorities and on regional languages

THE SCIENTIFIC ASPECTS IN REGULATIONS RELATED TO MUSEUMS

As far as the scientific context is concerned, the activities performed by museums may be divided into two categories: museums serve persons and subjects conducting scientific research and perform scientific activity by for example producing scientific publications. The types of scientific activities mentioned above performed by museums are reflected in official setting of museum’s objectives and activities specified in statutes and regulations. In particular, the scientific activity is essential for registered museums listed in the National Museums Register. In order to be listed in this Register, a museum must represent i.a. high level of accomplishments in the field of diverse scientific activities and posses an appropriate research staff. Professional achievements in the field of research were also included in the regulation regarding qualifications required for museum professionals. Moreover, the activity of museums may be analysed in the context of general regulations related to science, in particular the law on financing rules of science specifying scientific bodies, which are i.a. museums. The financial aspect of research activity performed by museums may be also analysed on the basis of public procurement rules (the Law on public procurement), which include exclusions regarding i.a. supplies and services exclusively for research or scientific purposes.Naukowy kontekst działalności muzeów może być rozpatrywany w dwóch aspektach: służebnej roli muzeów wobec innych osób i podmiotów, prowadzących badania naukowe oraz aktywności naukowej samych muzeów, polegającej m.in. na wydawaniu przez muzea publikacji naukowych. Obie powyższe sfery naukowego zaangażowania muzeów znajdują swój wyraz w ustawowym określeniu celów i działań muzeów, precyzowanych w ich statutach lub regulaminach. Aktywność naukowa jest szczególnie istotna w przypadku muzeów rejestrowanych, figurujących w Państwowym Rejestrze Muzeów. Wpis do tego rejestru warunkowany jest m.in. wysokim poziomem związanym z osiągnięciami muzeum w dziedzinie różnych przedsięwzięć naukowych oraz zatrudnianiem odpowiedniej kadry naukowej. Osiągnięcia zawodowe w obszarze nauki zostały też uwzględnione w regulacji wymogów kwalifikacyjnych pracowników muzeów, zatrudnionych na stanowiskach muzealników. Działalność muzeów może być też rozpatrywana w kontekście ogólnych unormowań z zakresu nauki, w szczególności ustawy o zasadach finansowania nauki, określającej jednostki naukowe, którymi mogą być także muzea. Aspekt finansowy działalności naukowej muzeów może być też rozpatrywany na gruncie przepisów o zamówieniach publicznych (ustawy Prawo zamówień publicznych), zawierających wyłączenia dotyczące m.in. dostaw i usług służących wyłącznie do celów prac badawczych lub naukowych