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The Laser Interferometer Space Antenna (LISA) mission, scheduled for launch in the mid-2030s, is a gravitational wave space observatory designed to detect sources emitting in the millihertz band. LISA is an European Space Agency flagship mission, currently entering the Phase-B development phase. It is expected to help us improve our understanding of our Universe by measuring gravitational wave sources of different types, with some of the sources being at very high redshifts (z ∼ 2 0). On February 23, 2022, we organized the first LISA in Greece Workshop. This Workshop aimed to inform the Greek scientific and tech industry communities about the possibilities of participating in LISA science and the LISA mission, with the support of the Hellenic Space Center. In this White Paper, we summarize the outcomes of the Workshop, the most important aspect of it being the inclusion of 1 5 Greek researchers to the LISA Consortium, raising our total number to 2 2. At the same time, we present a road map with the future steps and actions of the Greek Gravitational Wave community with respect to the LISA mission. [ABSTRACT FROM AUTHOR]

We present the analysis of the stellar population and star formation history of 181 MIRI selected galaxies at z  = 0 − 3.5 in the massive galaxy cluster field SMACS J0723.3–7327, commonly referred to as SMACS0723, using the JWST Mid-Infrared Instrument (MIRI). We combine the data with the JWST Near Infrared Camera (NIRCam) catalogue, in conjunction with the Hubble Space Telescope (HST) WFC3/IR and ACS imaging. We find that the MIRI bands capture PAH features and dust emission, significantly enhancing the accuracy of photometric redshift and measurements of the physical properties of these galaxies. The median photo- z 's of galaxies with MIRI data are found to have a small 0.1 per cent difference from spectroscopic redshifts and reducing the error by 20 per cent. With MIRI data included in SED fits, we find that the measured stellar masses are unchanged, while the star formation rate is slightly lower by 0.1 dex. We also fit the median SED of active galactic nuclei (AGNs) and star-forming galaxies (SFG) separately. MIRI data provides tighter constraints on the AGN contribution, reducing the typical AGN contributions by ∼15 per cent. In addition, we also compare the median SED obtained with and without MIRI, and we find that including MIRI data yields steeper optical and UV slopes, indicating bluer colours, lower dust attenuation, and younger stellar populations. In the future, MIRI/MRS will enhance our understanding by providing more detailed spectral information and allowing for the study of specific emission features and diagnostics associated with AGN. [ABSTRACT FROM AUTHOR]

Mechanochromic materials have been attractive to researchers in recent years due to their wide applications. However, traditional petrochemical-based mechanochromic materials are probably faced with problems of non-renewability and poor sustainability. Hence, it is of great significance to develop mechanochromic materials from phytochemicals endowed with renewability and sustainability. Herein, after combining the tetraphenylethene motif with a rosin-originated phytochemical, dehydroabietic acid, two natural rosin-based aggregation-induced emission (BioAIE) luminogens, DAA-TPE and DAMBA-TPE , were separately obtained on distinct Schiff base reaction sites. Both compounds have AIE phenomena mainly due to the introduction of tetraphenylethene group. However, their other optical properties are totally different depending on the imine site. DAMBA-TPE (imine on the aromatic site of dehydroabietic acid) shows very weak fluorescence at aggregate state, while DAA-TPE (imine on the alkyl site of dehydroabietic acid) exhibits strong emission and high contrast mechanochromic behavior in the solid state. Via the introduction of naturally large alkyl substitution, the pristine powder can be illuminated with a red shift of 28 nm from blue (442 nm) to cyan (470 nm) upon grinding. While a structurally analogue with a small iso -butyl substitution does not possess mechanochromism. Moreover, the fluorescence of DAA-TPE can be reversibly switched, which is most probably attributed to the crystal form change before and after grinding. This property endows DAA-TPE with potential application in the manufacturing of rewritable paper. Last but not least, this work paves a way to the design of mechanochromic materials from naturally renewable resources via introduction of large alkyl groups on the TPE skeleton. Two rosin-derived BioAIEgens with distinct fluorescence and mechanochromic properties have been easily obtained via the introduction of naturally large DA moieties. [Display omitted] • Melding the large DA moiety on the TPE skeleton, two rosin-based BioAIEgens can be easily obtained. • DAA-TPE exhibits strong solid-state emission, while DAMBA-TPE is only weakly emissive in the aggregate state. • The introduction of DA can result in reversible mechanochromic property, leading to application as rewritable materials. [ABSTRACT FROM AUTHOR]

In this paper, we explore the molecular basis of combining photodynamic therapy (PDT), a light-triggered targeted anticancer therapy, with the traditional chemotherapeutic properties of the well-known cytotoxic agent gemcitabine. A photosensitizer prerequisite is significant absorption of biocompatible light in the visible/near IR range, ideally between 600 and 1000 nm. We use highly accurate multiconfigurational CASSCF/MS-CASPT2/MM and TD-DFT methodologies to determine the absorption properties of a series of gemcitabine derivatives with the goal of red-shifting the UV absorption band toward the visible region and facilitating triplet state population. The choice of the substitutions and, thus, the rational design is based on important biochemical criteria and on derivatives whose synthesis is reported in the literature. The modifications tackled in this paper consist of: (i) substitution of the oxygen atom at O2 position with heavier atoms (O → S and O → Se) to red shift the absorption band and increase the spin–orbit coupling, (ii) addition of a lipophilic chain at the N7 position to enhance transport into cancer cells and slow down gemcitabine metabolism, and (iii) attachment of aromatic systems at C5 position to enhance red shift further. Results indicate that the combination of these three chemical modifications markedly shifts the absorption spectrum toward the 500 nm region and beyond and drastically increases spin–orbit coupling values, two key PDT requirements. The obtained theoretical predictions encourage biological studies to further develop this anticancer approach. [ABSTRACT FROM AUTHOR]

As observations of the Epoch of Reionization (EoR) in redshifted 21 cm emission begin, we assess the accuracy of the early catalog results from the Precision Array for Probing the Epoch of Reionization (PAPER) and the Murchison Wide-field Array (MWA). The MWA EoR approach derives much of its sensitivity from subtracting foregrounds to <1% precision, while the PAPER approach relies on the stability and symmetry of the primary beam. Both require an accurate flux calibration to set the amplitude of the measured power spectrum. The two instruments are very similar in resolution, sensitivity, sky coverage, and spectral range and have produced catalogs from nearly contemporaneous data. We use a Bayesian Markov Chain Monte Carlo fitting method to estimate that the two instruments are on the same flux scale to within 20% and find that the images are mostly in good agreement. We then investigate the source of the errors by comparing two overlapping MWA facets where we find that the differences are primarily related to an inaccurate model of the primary beam but also correlated errors in bright sources due to clean. We conclude with suggestions for mitigating and better characterizing these effects. [ABSTRACT FROM AUTHOR]

Studying quasars at the highest redshifts can constrain models of galaxy and black hole formation, and it also probes the intergalactic medium in the early universe. Optical surveys have to date discovered more than 60 quasars up to z ≃ 6.4, a limit set by the use of the z-band and CCD detectors. Only one z ≳ 6.4 quasar has been discovered, namely the z = 7.08 quasar ULAS J1120+0641, using near-infrared imaging. Here we report the discovery of three new z ≳ 6.4 quasars in 332 deg2 of the Visible and Infrared Survey Telescope for Astronomy Kilo-degree Infrared Galaxy (VIKING) survey, thus extending the number from 1 to 4. The newly discovered quasars have redshifts of z = 6.60, 6.75, and 6.89. The absolute magnitudes are between –26.0 and –25.5, 0.6-1.1 mag fainter than ULAS J1120+0641. Near-infrared spectroscopy revealed the Mg II emission line in all three objects. The quasars are powered by black holes with masses of ∼(1-2) × 109M☼. In our probed redshift range of 6.44 < z < 7.44 we can set a lower limit on the space density of supermassive black holes of ρ(MBH > 109M☼) > 1.1 × 10–9 Mpc–3. The discovery of three quasars in our survey area is consistent with the z = 6 quasar luminosity function when extrapolated to z ∼ 7. We do not find evidence for a steeper decline in the space density of quasars with increasing redshift from z = 6 to z = 7. [ABSTRACT FROM AUTHOR]

We report a plasmonic colorimetric sensing strategy using polyvinyl alcohol (PVA) modified silver nanoparticles (AgNPs) and paper-based analytical devices (PADs) for selective detection of lead (Pb). Method is based on the measurement of red shift of localized surface plasmon resonance (LSPR) absorption band of AgNPs/PVA in visible region after the addition of Pb(II) using UV–Vis spectrophotometry and color intensity of PADs was recorded with Smartphone followed by the processing in ImageJ software. The mechanism of color change and red shift (∆λ) of LSPR band from 410 nm to 550 nm is due to the interaction of Pb(II) ions towards the PVA through strong ion-dipole interaction perturbing the stability AgNPs which further directed the aggregation of particles. The density functional theory (DFT) using Gaussian (C.01) program assisted by experimental data was used to elucidate the plausible mechanism for selective detection of analyte. The calibration curve gave a good linearity in the range of 20–1000 μgL−1 with limit of detection (LOD) of 8 μgL−1 by colorimetry and 50–1000 μgL−1 with LOD value of 20 μgL−1 using PADs. In addition, the results obtained with UV–Vis and PADs were compared with ICP-AES for quantitative determination of Pb(II) in different water samples. The advantages of using AgNPs/PVA as plasmonic colorimetric probe and PADs found to be simple, low cost and selective for determination of lead from surface water and industrial waste water samples. • Plasmonic colorimetric sensing using silver nanoparticles and paper-based analytical devices for selective detection of Pb • Method is based on the measurement of red shift of LSPR band of AgNPs/PVA in visible region after the addition of Pb • Paper is based on color developement paper after addition of analyte followed by processing in ImageJ software • Density functional theory assisted by experimental data is used to elucidate the plausible mechanism for detection of Pb [ABSTRACT FROM AUTHOR]

Due to the widespread application of nonlinear optical materials, the design and synthesis of such materials with excellent performance has always been a research hotspot. In this paper, based on the reported TIDC-Cl, five new molecules were designed by introducing donor or acceptor units and their combination. By utilizing density functional theory and time-dependent density functional theory, the linear and nonlinear optical properties of molecules TIDC-Cl and 1–5 were investigated in detail. It was found that except for molecule 1, they are all narrowband compounds (1.41–2.22 eV), and their absorption spectra underwent a red shift, especially for molecules 2 and 4, which have reached the infrared region at long wavelengths. Molecule TIDC-Cl is a candidate for bipolar transport materials and molecules 2–5 are expected to serve as electron transport materials. Given that the studied molecules all have a large first hyperpolarizability, especially molecule 5, which is 807 times larger than that of the organic urea molecule, they are expected to serve as high-performance nonlinear optical materials. In addition, the origin of nonlinearity was studied through DR analysis, hyperpolarizability density analysis and the unit sphere representation method. The discussion of frequency-dependent (hyper)polarizability indicates that the frequency dispersion of the first hyperpolarizability appears in the studied molecules. It is hoped that this study will better promote the understanding of the nonlinear optical response of push–pull materials and pave the way for the development of high-tech nonlinear optical materials. [ABSTRACT FROM AUTHOR]

In the analytical process of spectrophotometry, the prerequisite for accurate qualitative and quantitative analysis is obtaining the intrinsic spectra of the analyte. However, the intrinsic properties of spectra can sometimes be masked by easily overlooked non-intrinsic factors, such as those from measuring instruments, leading to erroneous spectral identification. In this study, we documented an unusual redshift phenomenon in the far ultraviolet spectral region. With a spectrophotometer under the nitrogen atmosphere, we selected 14 representative inorganic anions and investigated their absorption spectral behaviors at different optical pathlengths and concentrations. It was intriguing to observe that the absorption peaks with maximum absorption wavelengths below a watershed wavelength of 200 nm underwent a redshift as pathlength and concentration increased, while those above 200 nm did not exhibit a significant redshift phenomenon. In-depth formula simulations and experimental verifications demonstrated that this peculiar spectral behavior was caused by unavoidable stray light in the spectrophotometer. Some methodological and instrumental recommendations are given in the paper. Our study results may serve as a reminder to carefully identify non-intrinsic phenomena when studying absorption spectra in the far ultraviolet region, and provide guidance on spectral corrections in scientific research and practical applications. [ABSTRACT FROM AUTHOR]

A recent JRASC paper (Brissenden 2020) demonstrated that a kinematic doppler interpretation of cosmological redshift can match Type 1a supernova measurements without expanding space or dark energy. Tis result is reviewed, and the omission of gravitational redshift, implications for general relativity, and the relevance of Milne cosmology are discussed. A new cosmological model is described where radius r replaces coordinate time-based ct. With this model, expansion of the Universe is associated with a kinematic increase in radius, and not the Friedmann-Robertson-Walker expanding space scale factor, a(t). A new metric tensor is proposed, to replace the FRW metric of standard cosmological theory. [ABSTRACT FROM AUTHOR]

In this paper, the structural, electrical and optical effects of WS2 doped with silicon atoms after torsional deformation are investigated using first-principles calculations. First-principles calculations for metal disulfide-WS2. The doping of Si atoms gives WS2 a tunable band gap, and the surface state is successfully transformed from a 2.0 eV band gap to a quasi-metal with a 0.254 eV band gap, and the change of the doped Si atoms causes a redshift in the absorption peak and a blueshift in the reflection peak. The band gap of WS2 can be effectively adjusted by torsional deformation on the basis of Si-doped atoms in the range 0.254–0.052 eV. Calculations of optical properties show that Si-doped WS2 with a torsion angle of 1 0 ∘ has the lowest light absorption peak and Si-doped WS2 with a torsion angle of 8 ∘ has the lowest light reflection peak. This paper opens up new possibilities for designing materials on demand. [ABSTRACT FROM AUTHOR]

This study presents the capabilities of the AXIS telescope in estimating redshifts from X-ray spectra alone (X-ray redshifts, XZs). Through extensive simulations, we establish that AXIS observations enable reliable XZ estimates for more than 5500 obscured active galactic nuclei (AGNs) up to redshift z ∼ 6 in the proposed deep (7 Ms) and intermediate (375 ks) surveys. Notably, at least 1600 of them are expected to be in the Compton-thick regime ( log N H / cm − 2 ≥ 24 ), underscoring the pivotal role of AXIS in sampling these elusive objects that continue to be poorly understood. XZs provide an efficient alternative for optical/infrared faint sources, overcoming the need for time-consuming spectroscopy, the potential limitations of photometric redshifts, and potential issues related to multi-band counterpart association. This approach will significantly enhance the accuracy of constraints on the X-ray luminosity function and obscured AGN fractions up to high redshifts. This white paper is part of a series commissioned for the AXIS Probe Concept Mission; additional AXIS white papers can be found at the AXIS website. [ABSTRACT FROM AUTHOR]

In this paper, we discuss an extension of the geometric description of graphene wormholes in a non-inertial situation. We present an effective metric that describes the wormhole connection between two graphene sheets with matter content in rotation. Additionally, a stretching term as a function of the classical redshift of space has been found and discussed. We also explore the influence of a rotation term on quantum holonomy, recovering previous results found for the static case. [ABSTRACT FROM AUTHOR]

We examine the black-hole limits of the family of static and spherically symmetric solutions of the Einstein field equations for polytropic matter, that was presented in a previous paper. This exploration is done in the asymptotic sub-regions of the allowed regions of the parameter planes of that family of solutions, for a few values of the polytropic index n, with the limitation that n > 1 . These allowed regions were determined and discussed in some detail in another previous paper. The characteristics of these limits are examined and analyzed. We find that there are different types of black-hole limits, with specific characteristics involving the local temperature of the matter. We also find that the limits produce a very unexpected but specific type of spacetime geometry in the interior of the black holes, which we analyze in detail. Regarding the spatial part of the interior geometry, we show that in the black-hole limits there is a general collapse of all spatial distances to zero. Regarding the temporal part, there results an infinite overall red shift in the limits, with respect to the flat space at radial infinity, over the whole interior region. The analysis of the interior geometry leads to a very surprising connection with quantum-mechanical studies in the background metric of a naked Schwarzschild black hole. The nature of the solutions in the black-hole limits leads to the definition of a new type of singularity in General Relativity. We argue that the black-hole limits cannot actually be taken all the way to their ultimate conclusion, due to the fact that this would lead to the violation of some essential physical and mathematical conditions. These include questions of consistency of the solutions, questions involving infinite energies, and questions involving violations of the quantum behavior of matter. However, one can still approach these limiting situations to a very significant degree, from the physical standpoint, so that the limits can still be considered, at least for some purposes, as useful and simpler approximate representations of physically realizable configurations with rather extreme properties. [ABSTRACT FROM AUTHOR]

Some remarks to paper of M. Kafatos et al. are given. [ABSTRACT FROM AUTHOR]

'Small-scale cosmology' is a theory designed to incorporate the linear redshift versus distance relation, which is inferred from observations, into the theoretical framework independent of the global Robertson–Walker–Friedman (RWF)-type models. The motivation behind this is that the RWF cosmological models, based on the assumptions of homogeneity and a constant matter density, as well as the concept of expanding space inherent to them are not applicable on the scales of observations from which the linear Hubble law is inferred. Therefore, explaining the Hubble law as the small redshift limit of the RWF model or as an effect of expanding space is inconsistent. Thus, the Hubble linear relation between the redshift of an extragalactic object and its distance should be considered an independent law of nature valid in the range of the distances where the RWF cosmology is not valid. In general, the theory, based on that concept, can be developed in different ways. In the present paper, 'small-scale cosmology' is formulated as a theory operating in the (redshift–object coordinates) space, which allows developing a conceptual and computational basis of the theory along the lines of that of special relativity. In such a theory, the condition of invariance of the Hubble law with respect to a change in the observer acceleration plays a central role. In pursuing this approach, the effectiveness of group theoretical methods is exploited. Applying the Lie group method yields transformations of the variables (the redshift and space coordinates of a cosmological object) between the reference frames of the accelerated observers. In this paper, the transformations are applied to studying the effects of the solar system observer acceleration on the observed shape, distribution and rotation curves of galaxy clusters. [ABSTRACT FROM AUTHOR]

In a previous paper, we demonstrated a single-rung method for measuring cosmological distances in active galactic nuclei (AGNs) that can be used from low redshift (z < 0.1) to high redshift (z > 3). This method relies on the assumption that the variability seen in AGNs is constrained by the speed of light during a flare event and can therefore be used to estimate the size of an emitting region. A limitation of this method is that previously, the Doppler factor was required to be known. In this paper, we derive an extension of the 'standard speed-gun' method for measuring cosmological distances that depends on the maximum intrinsic brightness temperature that a source can reach, rather than the Doppler factor. If the precise value of the intrinsic brightness temperature does not evolve with redshift, and flares are statistically independent, we can in principle improve the errors on measurements of the matter content of the Universe (in a flat Lambda cold dark matter model) statistically. We then explored how well a future observing programme would constrain cosmological parameters. We found that recovering the input cosmology depends critically on the uncertainty of the intrinsic brightness temperature and the number of flares observed. [ABSTRACT FROM AUTHOR]

The epoch of the reionization (EoR) power spectrum is expected to evolve strongly with redshift, and it is this variation with cosmic history that will allow us to begin to place constraints on the physics of reionization. The primary obstacle to the measurement of the EoR power spectrum is bright foreground emission. We present an analysis of observations from the Donald C. Backer Precision Array for Probing the Epoch of Reionization (PAPER) telescope, which place new limits on the H i power spectrum over the redshift range of , extending previously published single-redshift results to cover the full range accessible to the instrument. To suppress foregrounds, we use filtering techniques that take advantage of the large instrumental bandwidth to isolate and suppress foreground leakage into the interesting regions of k-space. Our 500 hr integration is the longest such yet recorded and demonstrates this method to a dynamic range of 104. Power spectra at different points across the redshift range reveal the variable efficacy of the foreground isolation. Noise-limited measurements of Δ2 at k = 0.2 hr Mpc−1 and z = 7.55 reach as low as (48 mK)2 (1σ). We demonstrate that the size of the error bars in our power spectrum measurement as generated by a bootstrap method is consistent with the fluctuations due to thermal noise. Relative to this thermal noise, most spectra exhibit an excess of power at a few sigma. The likely sources of this excess include residual foreground leakage, particularly at the highest redshift, unflagged radio frequency interference, and calibration errors. We conclude by discussing data reduction improvements that promise to remove much of this excess. [ABSTRACT FROM AUTHOR]

Several large JWST blank field observing programs have not yet discovered the first galaxies expected to form at 15 ≤ z ≤ 20. This has motivated the search for more effective survey strategies that will be able to effectively probe this redshift range. Here, we explore the use of gravitationally lensed cluster fields, which have historically been the most effective discovery tool with the Hubble Space Telescope. In this paper, we analyze the effectiveness of the most massive galaxy clusters that provide the highest median magnification factor within a single JWST NIRCam module in uncovering this population. The results of exploiting these lensing clusters to break the z > 15 barrier are compared against the results from large-area, blank-field surveys such as JADES and CEERS in order to determine the most effective survey strategy for JWST. We report that the fields containing massive foreground galaxy clusters specifically chosen to occupy the largest fraction of a single NIRCam module with high magnification factors in the source plane while containing all multiple images in the image plane within a single module provide the highest probability of both probing the 15 ≤ z ≤ 20 regime as well as discovering the highest-redshift galaxy possible with JWST. We also find that using multiple massive clusters in exchange for shallower survey depths is a more time-efficient method of probing the z > 15 regime. [ABSTRACT FROM AUTHOR]

In this paper we propose a reinterpretation of the Mansouri–Nozari signature-change approach to the early Universe, in which the metric signature only occurs for t < 0 within the Euclidean regime, posing a challenge in providing coherent physical interpretations in advance. We ensure that the sign change occurs for t > 0 in the Euclidean regime. Our findings show that the energy-momentum tensor does not vanish on the signature-changing surface, even when we adopt conditions commonly used in the literature. Furthermore, we formulate a modified cosmology within the framework of signature-changing and discuss the modifications that our approach introduces to the cosmological equations. We establish a constraint relating the equation of state parameter and its singular part and we determine an effective equation of state as function of the redshift. Finally, we show that the law of conservation of matter in the modified ΛCDM model remains valid. [ABSTRACT FROM AUTHOR]

The spin-torsion theory is a gauge theory approach to gravity that expands upon Einstein's general relativity (GR) by incorporating the spin of microparticles. In this study, we further develop the spin-torsion theory to examine spherically symmetric and static gravitational systems that involve free-falling macroscopic particles. We posit that the quantum spin of macroscopic matter becomes noteworthy at cosmic scales. We further assume that the Dirac spinor and Dirac equation adequately capture all essential physical characteristics of the particles and their associated processes. A crucial aspect of our approach involves substituting the constant mass in the Dirac equation with a scale function, allowing us to establish a connection between quantum effects and the scale of gravitational systems. This mechanism ensures that the quantum effect of macroscopic matter is scale-dependent and diminishes locally, a phenomenon not observed in microparticles. For any given matter density distribution, our theory predicts an additional quantum term, the quantum potential energy (QPE), within the mass expression. The QPE induces time dilation and distance contraction, and thus mimics a gravitational well. When applied to cosmology, our theory yields a static cosmological model. The QPE serves as a counterpart to the cosmological constant introduced by Einstein to balance gravity in his static cosmological model. The QPE also offers a plausible explanation for the origin of Hubble redshift (traditionally attributed to the universe's expansion). The predicted luminosity distance–redshift relation aligns remarkably well with SNe Ia data from the cosmological sample of SNe Ia. In the context of galaxies, the QPE functions as the equivalent of dark matter. The predicted circular velocities align well with rotation curve data from the SPARC (Spitzer Photometry and Accurate Rotation Curves database) sample. Importantly, our conclusions in this paper are reached through a conventional approach, with the sole assumption of the quantum effects of macroscopic matter at large scales, without the need for additional modifications or assumptions. [ABSTRACT FROM AUTHOR]

In developing his cosmological model of 1917, de Sitter theoretically predicted the phenomenon of cosmological redshift (the de Sitter effect), which he did long before the discovery of this phenomenon in observations. The de Sitter effect is gravitational by its nature, as it is due to differences between the coordinate systems of the observer and the distant source. However, the relationship between the redshift and distance derived from the de Sitter metric is at odds with observations, since this relationship is nonlinear (quadratic) for small redshifts, while the observed relationship between the same quantities is strictly linear. This paper discusses the possibility that cosmological redshift is gravitational by its nature, as in de Sitter's 1917 model. At the same time, here, as in de Sitter's model, an elliptical space is used, the main characteristic of which is the identification of its antipodal points. But, unlike de Sitter's model, here, in order to ensure strict linear dependence of the redshift on distance, the origin of the reference system is transferred to the observer's antipodal point. The Schwarzschild–de Sitter metric used in this model allows you to estimate the curvature of space from observational data. To achieve this, a theoretical Hubble diagram is built within the framework of the model with the Schwarzschild–de Sitter metric, which is compared with observations from the Pantheon+ catalogue of type Ia supernovae and the Amati catalogue of gamma-ray bursts in the redshift range of 0 < z < 8 . As a result of this comparison, we found that the lower estimate of the radius of curvature of space was quite large: 2.4 × 10 15 Mpc. This means that the observational data indicate a negligible curvature of space. [ABSTRACT FROM AUTHOR]

Filter elements based on metamaterial structure are one of the essential schemes for researching the miniaturization of spectral detection systems. The aim of this study is to meet the application requirements of different long-wave infrared signal frequency filtering and improve the detection efficiency of micro-filters. In this paper, a periodic micro-nano-cross-linked hole structure is designed, based on the surface plasmonic polariton resonance effect to realize the extraordinary optical transmission performance of 8 ~ 12 μm long-wave infrared. Based on the surface plasmonic polariton excitation mechanism of periodic micro-nano-structures, the tunable performance of the transmission spectra at five central wavelengths of 8, 9, 10, 11, and 12 μm was achieved by changing the simulation period and the overall period of the model, and the optimal peak transmittance was 88.31% with a half-wave width of 1.31 ± 0.01 μm. The present study summarizes the tuning mode and rule of the micro-nano-cross-linked structure to realize the blue/redshift under the performance of the extraordinary optical transmission, which provides an important reference for the miniaturized structure design of infrared spectral detectors and tunable filtering research and is conducive to the application of broadband filtering spectral chips. [ABSTRACT FROM AUTHOR]

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It is known that dimensional constants, such as ℏ, c, G, e, and k, are merely human constructs whose values and units vary depending on the chosen system of measurement. Therefore, the time variations in dimensional constants lack operational significance due to their dependence on these dimensional constants. They are well structured and represent a valid discussion. However, this fact only becomes a meaningful debate within the context of a static or present Universe. As theoretically and observationally well established, the current Universe is undergoing accelerated expansion, wherein dimensional quantities, like the wavelength of light, also experience redshift phenomena elongating over cosmic time. In other words, in an expanding Universe, dimensional quantities of physical parameters vary with cosmic time. From this perspective, there exists the possibility that dimensional constants, such as the speed of light, could vary with the expansion of the Universe. In this review paper, we contemplate under what circumstances the speed of light may change or remain constant over cosmic time and discuss the potential for distinguishing these cases observationally. [ABSTRACT FROM AUTHOR]

This paper proposes a hybrid approach integrating the expert knowledge judgment approach using the Cognitive Pairwise Comparison (CPC) to the Deep Learning, a modern classification approach, for astronomic object classification. The astronomic data with ten thousand samples retrieved from Sloan Digital Sky Survey Sky Server Data Release 15 (SDSS SkyServer DR 15) are used for this study. The CPC is an approach to elicit and encode expert knowledge in the format of a Pairwise Opposite Matrix (POM) to evaluate expert preferences for the features. A forward feature selection algorithm taking the expert choices using CPC for the ordered features is used for the feature selection for the deep learning algorithm to build a heuristic training model based on the astronomic data. Whilst the accuracy of the case of improper feature selection is just 37.1%, the proposed hybrid approach can obtain a very high accuracy of 97.9% for the classification of the astronomic object using the eight scaled features (u, g, r, i, z redshift, ra, dec). To extend this research, the proposed CPC can be used as a human-centered tool to be applied to other areas of data sciences. [ABSTRACT FROM AUTHOR]

Context: Since 1991 when Grätzel et al. improved the conversion efficiency of dye-sensitized solar cells to 7.1% by applying nano technology as the first time, the researches on dye-sensitized solar cells have received widely attentions. The organic dye without precious metals has a lower cost, which is easily to get synthesized and its structure is easily decorated, owing a higher photoelectric conversion efficiency at the same time. Therefore, in recent years, the organic dye has attracted people's attentions more and more. In order to better understand the relationship between structure and properties of dye molecules, with ZL003 as a prototype, molecular modifications are then made and a scheme, with rigid fused π-bridge comprising electron-rich and deficient segments. The calculated results indicate that the π-bridge containing dithienopyrrolobenzothiadiazole and dipyrrolo-dithienobenzothiadiazole as π-bridge has been demonstrated to be successful to significantly redshift the absorption maximum wavelength, extend the lifetime of the first excited state, and decrease the energy gap between the highest occupied molecule orbital (HOMO) and the lowest unoccupied molecule orbital (LUMO). It is hoped that the calculation result of this paper would provide theoretical basis for the experimental synthesis of more efficient dye molecules. Method: All calculations were performed in Gaussian 09 program package. The ground state geometries (S0) and the first excited state (S1) were optimized using density function theory (DFT) with the hybrid function B3LYP functional, coupled with the 6-31G(d, p) basis set for optimization of molecule ground state conformations. TD-DFT calculations of excited state energies and absorption spectra were performed using MPWPW91 functional combined with the 6–31 + G (d) basis set. [ABSTRACT FROM AUTHOR]

This paper reports the first variationally based predictions of the lowest excited state in diamond (Γ25′ → Γ15) in the unrelaxed (optical) and structurally relaxed (thermal) configurations, from direct Δ-self-consistent-field (SCF) calculations based on B3LYP, PBE0, HSE06, and GGA functionals. For the B3LYP functional, which has the best overall performance, the energy of the optical state, 7.27 eV, is within the observed range of (7.2–7.4) eV and is predicted to be insulating, with indirect bandgaps of (5.6–5.8) eV. Mulliken analyses of the excited state wavefunction indicate extensive redistributions of charge and spin resulting in a strongly excitonic state with a central charge of −0.8ǀeǀ surrounded by charges of +0.12ǀeǀ at the four nearest neighbor sites. The thermally relaxed state is predicted to be similarly excitonic, with comparable bandgaps and atomic charges. Calculations of the ground and excited state relaxations lead to a Stokes shift of 0.47 eV and predicted Γ-point luminescence energy of 6.89 eV. Assuming a similar shift at the band edge (X1), an estimate of 5.29 eV is predicted for the luminescence energy, which compares with the observed value of 5.27 eV. Excited state vibrational spectra show marked differences from the ground state, with the introduction of an infrared peak at 1150 cm−1 and a modest shift of 2 cm−1 in the TO(X) Raman mode at 1340 cm−1. Similar calculations of the lowest energy bi- and triexcitons predict these to be bound states in both optical and thermal configurations and plausible precursors to exciton condensation. Estimates of bi- and triexciton luminescence energies predict red shifts with respect to the single exciton line, which are compared to the recently reported values. [ABSTRACT FROM AUTHOR]

This article presents information on forthcoming papers on biochemistry, to be published in the periodical "European Journal of Biochemistry." The papers include "Expression in Escherichia Coli of a Secreted Invertebrate Ferritin," by Matthias von Dart, Pauline M. Harrison and Werner Bottke, "Regulation of Protein Kinase A Subunits During Germination of Mucor Rouxii Sporangiospores," by Silvia Rossi and Silvia Moreno and "Optical Spectrum of Myeloperoxidase — Origin of the Red Shift," by René Plans, Younkyoo Kim, Gerald T. Babcock and Ron Wever.

The non-linear relationship between the monochromatic X-ray and UV luminosities in quasars offers the possibility of using high-z quasars as standard candles for cosmological testing. In this paper, we use a high-quality catalog of 1598 quasars extending to redshift ∼ 6 , to compare the flat and uniformly expanding cosmological model, R h = c t and Λ CDM cosmological models which are the most debated. The quasar samples are mainly from the XMM-Newton and the Sloan Digital Sky Survey (SDSS). The final result is that the Akaike Information Criterion favors Λ CDM over R h = c t with a relative probability of ∼ 86.30 % versus ∼ 13.70 % . [ABSTRACT FROM AUTHOR]

As part of the "Cosmological Distance Scale" series, the paper focuses on the cosmic jerk issue. Drawing on the data for the parametric identification of the Friedmann–Robertson–Walker model as the dependence of photometric distance on Type Ia supernova (SN Ia) redshift used by the High-Z SN Search Team and Supernovae Cosmology Project, it is considered whether the accelerating expansion of the universe can be assumed to be the most plausible hypothesis under the criterion of minimum inadequacy error. The previously detected change points (structural and parameter changes in the systematic component of the model) and rank inversions of SN Ia photometric distances for the systematic component of this model are analyzed. It is shown that these metric disruptions are caused by the isotropy of the Friedmann-Robertson-Walker model. In the anisotropic model of the cosmological distance scale, change points and rank inversions are associated with the gravitational dipole orientation of inhomogeneity in the large-scale structure of the universe. These dipoles represent diametrically opposite "supercluster–giant void" pairs on the celestial sphere. Only the size of the supervoid in the constellation of Eridanus, comparable to that of the observable part of the universe, causes a great imbalance in the gravitational effect of the massive supercluster. This leads to disruptions in the form of change points and rank inversions in the isotropic models of the Friedmann–Robertson–Walker type. [ABSTRACT FROM AUTHOR]

Considering our recently proposed light speed expanding Hubble-Hawking Universe and considering the recent paper pertaining to cosmic halt authored by Cosmin Andrei, Anna Ijjas, and Paul J. Steinhardt and reviewed by Saul Perlmutter, in this paper we propose a very simple model of universe having early stage light speed expansion and current stage quantum halt accompanied by light speed rotation. Representing early cosmic expansion and rotation as an outward spiral, Hubble's law can be considered as a representation of current cosmic rotation having no further expansion. Proceeding further, we would like to emphasize the point that, traditional definition of cosmic red shift is absolutely wrong. Based on photon energy, true cosmic red shift must be defined as the ratio of change in wavelength to the observed wavelength of photon. Halting state of the current universe can be understood with a combined study of the gravitational potential energy of proton and electron separated by a distance of 0.84 fermi and half the product of reduced Planck's constant and current Hubble parameter. [ABSTRACT FROM AUTHOR]

Indacenodithiophene (IDT)‐based high‐efficiency photovoltaics have received increasing attention recently. This paper reports a density functional theory investigation of the electronic and optical properties of three IDT‐based organic dyes together with the dye/(TiO2)46 interface. In order to enhance the photoelectric properties of IDT dyes, this paper considers two methods for the structure modification of the experimentally reported dye DPInDT (J. Org. Chem. 2011, 76, 8977): the extension of the conjugation length by dithienothiophene as well as the heteroatom substitution of the bridging atoms by electron‐rich nitrogen atoms. Our calculations show that both methods obviously affect the distributions of the molecular orbitals and notably red shift the absorption peaks of around 20 nm, with the former method demonstrating enhanced light harvesting efficiency. The structure modifications proposed also enhance the emission spectrum properties for IDT‐based organic dyes. The calculated ultrafast injection time of electrons from the excited state of IDT dyes to the (TiO2)46 belongs to the femtosecond order of magnitude, and is ideal for efficient photoelectric conversion process in dye‐sensitized solar cells (DSSCs) applications. The IDT dyes designed in this paper have good electronic and spectroscopic properties. This study is expected to provide useful guidance for the development of novel IDT dyes for applications in DSSCs. [ABSTRACT FROM AUTHOR]

Narrowband optical absorption plays a key role in photonic sensors and photovoltaic elements. Here, we propose a design of creating narrowband absorbers based on the symmetric and asymmetric defective photonic crystals (SDPCs and ADPCs) consisting of defects in the form of DMD in which M indicates the WS2 or WSe2 monolayer and D represents the SiO2 layer. In this paper, the effect of the defect layer thickness, polarization, and incident angle of light on the number and wavelength of defect modes in both symmetric and asymmetric structures is investigated. The findings suggest that the wavelength of the defect modes can be adjusted by varying the thickness of layer D as well as the design of the wavelength and tuned by polarization and incident angle of light. In both SDPC and ADPC, the wavelength of the defect mode shows red shift with an increase in the thickness of layer D and exhibits blue shift with an increase in the angle of light in both TE and TM polarization. This narrowband absorber demonstrates great potential for being adopted in the detection of photodetectors, absorbent filters, and the like. [ABSTRACT FROM AUTHOR]

Line intensity mapping (LIM) can provide a powerful means to constrain the theory of gravity and the nature of dark energy at low and high redshifts by mapping the large-scale structure over many redshift epochs. In this paper, we investigate the potential of the next generation ground-based millimeter-wavelength LIM surveys in constraining several models beyond ΛCDM, involving either a dynamic dark energy component or modifications of the theory of gravity. Limiting ourselves to two-point clustering statistics, we consider the measurements of auto-spectra of several CO rotational lines (from J = 2−1 to J = 6−5) and the [C ii ] fine structure line in the redshift range of 0.25 < z < 12. We consider different models beyond ΛCDM, each one with different signatures and peculiarities. Among them, we focus on Jordan–Brans–Dicke and axion-driven early dark energy models as examples of well-studied scalar-tensor theories acting at late and early times, respectively. Additionally, we consider three phenomenological models based on an effective description of gravity at cosmological scales. We show that LIM surveys deployable within a decade (with ∼108 spectrometer hours) have the potential to improve upon the current bounds on all considered models significantly. The level of improvements range from a factor of a few to an order of magnitude. [ABSTRACT FROM AUTHOR]