Red Clusters Research Articles

Differential regulation of undecylprodigiosin biosynthesis in the yeast-scavenging Streptomyces strain MBK6.

ABSTRACT Streptomyces are efficient chemists with a capacity to generate diverse and potent chemical scaffolds. The secondary metabolism of these soil-dwelling prokaryotes is stimulated upon interaction with other microbes in their complex ecosystem. We observed such an interaction when a Streptomyces isolate was cultivated in a media supplemented with dead yeast cells. Whole-genome analysis revealed that Streptomyces sp. MBK6 harbors the red cluster that is cryptic under normal environmental conditions. An interactive culture of MBK6 with dead yeast triggered the production of the red pigments metacycloprodigiosin and undecylprodigiosin. Streptomyces sp. MBK6 scavenges dead-yeast cells and preferentially grows in aggregates of sequestered yeasts within its mycelial network. We identified that the activation depends on the cluster-situated regulator, mbkZ, which may act as a cross-regulator. Cloning of this master regulator mbkZ in S. coelicolor with a constitutive promoter and promoter-deprived conditions generated different production levels of the red pigments. These surprising results were further validated by DNA–protein binding assays. The presence of the red cluster in Streptomyces sp. MBK6 provides a vivid example of horizontal gene transfer of an entire metabolic pathway followed by differential adaptation to a new environment through mutations in the receiver domain of the key regulatory protein MbkZ.

Methylene blue-mediated antimicrobial photodynamic therapy can be a novel non-antibiotic platform for bovine digital dermatitis

BackgroundBovine digital dermatitis (BDD) is one of the most important diseases that effect dairy cows. Methylene blue-mediated antimicrobial photodynamic therapy (MB-APDT) emerges as a promising technique to treat superficial infections in bovines. MethodsTwenty BDD lesions located at the skin horn transition of the claw of pelvic limbs of 16 cows were treated by MB-APDT, using a red LED cluster (λ = 660 nm, irradiance =60 mW/cm2, exposure time = 40 s) combined with topical application of MB at 0.01 %; or by topical application of OXY (500 mg in 20 % solution). Each lesion was treated twice with an interval of 14 days. Lesions were weekly evaluated until day 28 by clinical analysis and by histological examination on days 0 and 28. ResultsBoth treatments led to a similar reduction of lesions area. At day 28, three lesions treated by OXY did not present completely recovery, whereas no lesions were observed in MB-APDT group. OXY resulted in a slight increase in type I and III collagen levels, while MB-APDT led to a significant increase in the total area of both collagen types. An abundant number of spirochetes were histologically observed in all lesions before treatments. On the 28th day, five lesions treated by OXY still presented a slight number of spirochetes, whereas in MB-APDT group no spirochetes were evidenced. ConclusionOur findings suggest that MB-APDT is more effective than OXY and could be used in Veterinary practice to fight BDD.

PRELIMINARY APPLICATION OF COLOR DESIGN ON CREATIVE PRODUCTS BY USING FUZZY CLUSTERING ANALYSIS- A CASE OF STARBUCKS MUG-ICON DESIGN

Colors attached to the external packaging surface of any creative design product are generally regarded as one of the crucial factors that attract consumers to purchase desires and enhance commercial values. However, it is difficult to quickly master the application skills of colors for beginners of learning design. To solve the possible problems in color learning, this study focused on the exploration of the color-plan drawn on mug-icons of Starbucks by using Fuzzy clustering analysis (FCA). The results showed that the color schemes of 175 types of mug-icons produced in European territory could be rapidly divided into four clusters including brown, red, blue, and green clusters based on the silhouette correlation coefficient (SC) and non-fuzziness index (NI). Particularly, of which the published rate of the blue cluster was higher (35.4%) than that of other clusters. It can be assumed that blue series are the main colors of the mug-icons of Starbucks produced in Europe whereas the outer characteristics relate to the statues, buildings, and skyline. In short, FCA has certain effectiveness and application potential for the rapid classification of colors and learning how to perform color-planning for beginners of design.

Phosphogypsum Recycling: A Review of Environmental Issues, Current Trends, and Prospects

The problem of recycling and storage of phosphogypsum is topical for many countries around the world, as it is associated with environmental problems of pollution of water bodies, land, and atmosphere. Therefore, this paper analyzes the directions of phosphogypsum recycling and possible alternatives to its use. The main disadvantages of the existing methods of phosphogypsum processing were identified and trends in this waste management were also considered. Through the VOSviewer programme, a visualization of cluster interconnections was carried out in research publications of various fields of phosphogypsum utilization. Five clusters were formed: a red cluster—phosphogypsum recycling in the construction industry; green cluster—radiation pollution problem of phosphogypsum and phosphate fertilizers; yellow cluster—monitoring migration of phosphogypsum components in the ecosystem, with the mobile forms of heavy metals and their inflow into aquifers from phosphogypsum dumps; blue cluster—use of phosphogypsum in agriculture as an ameliorant and a component of fertilizer; and a purple cluster—the impact of phosphogypsum on microorganisms, particularly in bioremediation processes. Under the proposed integrated biochemical approach, the use of various bioprocesses of phosphogypsum recovery from waste dumps and implementation of new biotechnological solutions for processing phosphorus raw materials are presented.

Classification of the Theses and Dissertations in the Field of Computer Education and Instructional Technology in Turkey: An Investigation through Text Mining

The rapid development of technology has led changes in educational paradigms in many areas of daily life. With this change, the integration of technology into educational environments and the organization of resources and processes have gained more importance. This situation reveals the need for educational technologies. There is a need for studies that can take a snapshot of the field for researchers to have a better understanding of the field. According to this need, it is aimed to take a snapshot of the area through text mining analysis would provide a wider perspective of the field. The results showed that the analyses on the keywords and summaries of the studies indicated that three clusters were formed according to the summaries and five different clusters were formed according to the keywords. Based on the findings of the current study, the appearance of instructional design in the red cluster and its divergence from other clusters indicate a key finding in terms of the field. It can be concluded that instructional design is used in the design of distance education environments, but in other clusters, instructional design is not a priority. However, the researchers in this field are expected that instructional design principles should be employed for diverse issues such as teaching programming, language teaching, and the use of social media in learning environments.

Trends in Graves' orbitopathy research in the past two decades: a bibliometric analysis.

This study was conducted to identify trends in Graves' orbitopathy research in the past two decades and to elaborate on hot topics in the field. The Web of Science database was used to extract articles on Graves' orbitopathy or its synonyms. Full data and references were exported to VOSviewer software to be analyzed. Visualization maps and charts were constructed accordingly. We retrieved 1067 articles on Graves' orbitopathy from the Web of Science database. The United States ranked first in terms of the article count (25), followed by Italy (141) and the People's Republic of China (120). Wiersinga's and the University of Amsterdam's articles received the highest citation count (1509 and 3052, respectively). The University of Pisa and Thyroid published the highest number of articles (65 and 93, respectively). Co-authorship analysis showed four clusters of country collaborations: red cluster, European countries; green cluster, the United States, Brazil, Canada, South Korea, and Taiwan; a yellow cluster, People's Republic of China; and blue cluster, Japan, Australia, and Poland. Keyword analysis revealed five clusters of topics: pathogenesis, management, association, quality of life, and surgery. Analysis of co-cited references also revealed five clusters: pathogenesis, management, risk factors, clinical assessment, and surgical management. Research on Graves' orbitopathy has grown during the past two decades. Hot research topics are pathogenesis, management, risk factors, quality of life, and complications. Research trends have changed in the past two decades. Increasing interest in exploring Graves' orbitopathy mechanisms and associations is evident. European countries are cooperating in this field of research. The United States has established more extensive international cooperation than other countries. We believe that more international collaboration involving developing countries is required.

Research trend on erbium-doped tellurite glasses based on scopus database

This paper aims to analyse the research trend of erbium-doped tellurite glasses. To this aim, this paper applied bibliometric analysis. The comprehensive research document on the topic of erbium-doped tellurite glasses in the Scopus database is 695 documents. The result revealed that scientific publication on erbium-doped tellurite glasses has been increasing. China contributed the most documents on erbium-doped tellurite glasses. The visualization of the research trend on erbium-doped tellurite glasses assisted with VOSviewer software and resulted in four primary clusters: (1) the red cluster show the keywords about the synthesized and fabrication, (2) the blue cluster show the keywords about the characterization, (3) the green cluster show the user or the application of the glass with each characteristic of materials, (4) the yellow cluster show the way to analyse energy based on the parameters owned by erbium-doped tellurite glasses. The research findings are the networking of the keywords on the research of erbium doped tellurite glasses in all clusters. It means that this research is comprehend knowledge and need to be more investigate to further research.

Singing Inside a Tree

Singing Inside a Tree Anne Haven McDonnell (bio) Many regions are projected to experience an increase in the probability of compound events with higher global warming (high confidence). In particular, concurrent heatwaves and droughts are likely to become more frequent. —Valérie Masson-Delmotte and Panmao Zhai, “Regional trends in extreme events in the IPCC 2021 report” The Celts believed a tree’s presence could be felt more keenly at night or after a heavy rain, and that certain people were more attuned to trees and better able to perceive them. There is a special word for this recognition of sentience, mothaitheacht. It was described as a feeling in the upper chest of some kind of energy or sound passing through you. It’s possible that mothaitheacht is an ancient expression of a concept that is relatively new to science: infrasound or “silent” sound. These are sounds pitched below the range of human hearing, which travel great distances by means of long, loping waves. They are produced by large animals, such as elephants, and by volcanoes. And these waves have been measured as they emanate from large trees. —Diana Beresford-Kroeger, To Speak for the Trees It is the balance between the rational and imaginative that will ultimately solve the most serious problems that threaten us. —David Dunn There’s a tree I see in my mind when I need to find shelter. This Douglas fir tree lives on an island in the northwest, and simultaneously this tree lives inside me. It’s one of the few remaining old-growth trees on the island. I’ve sat inside the burned-out cave at its base where lightning struck. I’ve watched light glitter across strands of spider silk spanning its entrance, breathing cool air and smelling damp earth, bark, and wood. Inside the tree, I am young and old and animal and human. I am held inside the slow language of xylem, [End Page 44] phloem, cambium, sap, and centuries of survival. When I approach the tree as I walk on the duff trail around the border of the lake, I feel the tree’s voice move like water through my chest. The voice of the tree is a hush, a swell, a silent rolling wave like the slow rising of a whale. There’s another kind of silence in my chest when I walk through the beetle-killed forests of northern New Mexico and Colorado. This silence is brittle. It spreads from too much sky, cracks along barkless gray branches, unsheltered, unsheltering. I’ve watched forest after forest that I love succumb to the mountain pine beetles. Where my mom has a cabin in the high Fraser Valley in Colorado, I’ve watched whole mountainsides of lodgepole pines erupt with sap balls along the trunk as they try to expunge the beetles. And then I’ve watched as rusty red clusters of dead needles spread like dull fire, until all the needles are rust. It’s almost the color of fall. It’s almost beautiful. Eventually the needles drop and leave skeletons of gray. What is called silence is usually the absence of human sounds. Inside the cave in my tree on the island, surrounded by Douglas fir, western red cedar, and hemlock forests, I hear the upward spiral of a russet-backed thrush, a loon calling from nearby on the lake, and the high tinkling glassy sounds of a Pacific wren. The thick layers of moss and duff and bark cushion each voice, as my body is held inside the body of the tree. Inside what used to be a living forest in the Rocky Mountains, inside what is now a tangle of fallen and standing dead lodgepole pine, I hear the far-off hammering of a woodpecker. Other than the woodpecker, all I hear is wind. I hear the way dead branches creak and carve the wind. What are the sounds of drought and climate unravelling in a forest? If you insert a homemade microphone inside the phloem and cambium of a drought-stressed piñon tree, as artist, composer, and acoustic ecologist David Dunn did, you’ll hear a symphony of sounds. I called David...

Pharmacognostic Properties of Quisqualis indica Linn: Against Human Pathogenic Microorganisms: An Insight Review

India has a large repository of medicinal plants that are used in traditional medical treatments. Several medicinal plants are useful for treating common ailments and some of the plants include Amla (Emblica cinalis), Ashoka (Saraca asoca), Aswagandha (Withania somnifera), Tulsi (Ocimum sanctum), Sarpa Gandha (Rauwolfia serpentina), Sandalwood (Santalum album), Indian birthwort (Aristolochia indica L.), Brahmi (Bacopa monnieri), Neem (Azardirchata indica), Vringraj (Eclipta alba), Grhit kumara (Aloe vera), Harida (Terminalia chebula) and Madhumalati (Quisqualis indica), Catnip (Nepeta cataria), Cayenne pepper (Capsicum annuum), Sage (Salvia officinalis); etc. Quisquails indica commonly known as the Madhu Malati, is a vine with red flower clusters and is found in abundance in India. It shows a wide range of remarkable medicinal properties. Over the last two decades, large scale research has been conducted to identify bio-active constituents of Quisqualis indica therapeutic prospects. This review summarizes the pharmacognostic properties of Quisqualis indica Linn. Against human pathogenic microorganisms. Several authors have reviewed the medicinal properties of Quisqualis indica Linn.but our review summarizes the anti-bacterial, anti-inflammatory, anti-oxidant, anti-pyretic, anti-helminthic, anti-diarrheal, anti-hyperglycemic, anti-microbial, anti-fungal and immuno-modulatory properties. It would be useful to students, academicians, microbiologists, as it reduces the need for detailed searching. It serves the purpose of quick reference.

Nonlinear Color–Metallicity Relations of Globular Clusters. IX. Different Radial Number Density Profiles between Blue and Red Clusters

Abstract The optical colors of globular clusters (GCs) in most large early-type galaxies are bimodal. Blue and red GCs show a sharp difference in the radial profile of their surface number density in the sense that red GCs are more centrally concentrated than blue GCs. An instant interpretation is that there exist two distinct GC subsystems having different radial distributions. This view, however, was challenged by a scenario in which, due to the nonlinear nature of the GC metallicity-to-color transformation for old (≳10 Gyr) GCs, a broad unimodal metallicity spread can exhibit a bimodal color distribution. Here we show, by simulating the radial trends in the GC color distributions of the four nearby giant elliptical galaxies (M87, M49, M60, and NGC 1399), that the difference in the radial profile between blue and red GCs stems naturally from the metallicity-to-color nonlinearity plus the well-known radial metallicity gradient of GC systems. The model suggests no or little radial variation in GC age even out to ∼20 R eff. Our results provide a simpler solution to the distinct radial profiles of blue and red GCs that does not necessarily invoke the presence of two GC subsystems and further fortify the nonlinearity scenario for the GC color bimodality phenomenon.

Prodiginines Postpone the Onset of Sporulation in Streptomyces coelicolor.

Bioactive natural products are typically secreted by the producer strain. Besides that, this allows the targeting of competitors, also filling a protective role, reducing the chance of self-killing. Surprisingly, DNA-degrading and membrane damaging prodiginines (PdGs) are only produced intracellularly, and are required for the onset of the second round of programmed cell death (PCD) in Streptomyces coelicolor. In this work, we investigated the influence of PdGs on the timing of the morphological differentiation of S. coelicolor. The deletion of the transcriptional activator gene redD that activates the red cluster for PdGs or nutrient-mediated reduction of PdG synthesis both resulted in the precocious appearance of mature spore chains. Transcriptional analysis revealed an accelerated expression of key developmental genes in the redD null mutant, including bldN for the developmental σ factor BldN which is essential for aerial mycelium formation. In contrast, PdG overproduction due to the enhanced copy number of redD resulted in a delay or block in sporulation. In addition, confocal fluorescence microscopy revealed that the earliest aerial hyphae do not produce PdGs. This suggests that filaments that eventually differentiate into spore chains and are hence required for survival of the colony, are excluded from the second round of PCD induced by PdGs. We propose that one of the roles of PdGs would be to delay the entrance of S. coelicolor into the dormancy state (sporulation) by inducing the leakage of the intracellular content of dying filaments thereby providing nutrients for the survivors.

Probing the cluster pressure profile with thermal Sunyaev–Zeldovich effect and weak lensing cross-correlation

ABSTRACT We confront the universal pressure profile (UPP) proposed. with the recent measurement of the cross-correlation function of the thermal Sunyaev–Zeldovich (tSZ) effect from Planck and weak gravitational lensing measurement from the Red Cluster Sequence Lensing Survey. By using the halo model, we calculate the prediction of ξy−κ (lensing convergence and Compton-y parameter) and $\xi ^{y-\gamma _{\rm t}}$ (lensing shear and Compton-y parameter) and fit the UPP parameters by using the observational data. We find consistent UPP parameters when fixing the cosmology to either WMAP 9-yr or Planck 2018 best-fitting values. The best constrained parameter is the pressure profile concentration c500 = r500/rs, for which we find $c_{500} = 2.68^{+1.46}_{-0.96}$ (WMAP-9) and $c_{500} = 1.91^{+1.07}_{-0.65}$ (Planck-2018) for the $\xi ^{y-\gamma _t}$ estimator. The shape index for the intermediate radius region α parameter is constrained to $\alpha =1.75^{+1.29}_{-0.77}$ and $\alpha = 1.65^{+0.74}_{-0.5}$ for WMAP-9 and Planck-2018 cosmologies, respectively. Propagating the uncertainties of the UPP parameters to pressure profiles results in a factor of 3 uncertainty in the shape and magnitude. Further investigation shows that most of the signal of the cross-correlation comes from the low-redshift, inner halo profile (r ≤ rvir/2) with halo mass in the range of 1014–$10^{15}{\, {\rm M}_{\odot }}$, suggesting that this is the major regime that constitutes the cross-correlation signal between weak lensing and tSZ.

AMICO galaxy clusters in KiDS-DR3: galaxy population properties and their redshift dependence

ABSTRACT A catalogue of galaxy clusters was obtained in an area of 414 $\deg ^2$ up to a redshift z ∼ 0.8 from the Data Release 3 of the Kilo-Degree Survey (KiDS-DR3), using the Adaptive Matched Identifier of Clustered Objects (amico) algorithm. The catalogue and the calibration of the richness–mass relation were presented in two companion papers. Here, we describe the selection of the cluster central galaxy and the classification of blue and red cluster members, and analyse the main cluster properties, such as the red/blue fraction, cluster mass, brightness, and stellar mass of the central galaxy, and their dependence on redshift and cluster richness. We use the Illustris-TNG simulation, which represents the state-of-the-art cosmological simulation of galaxy formation, as a benchmark for the interpretation of the results. A good agreement with simulations is found at low redshifts (z ≤ 0.4), while at higher redshifts the simulations indicate a lower fraction of blue galaxies than what found in the KiDS-amico catalogue: we argue that this may be due to an underestimate of star-forming galaxies in the simulations. The selection of clusters with a larger magnitude difference between the two brightest central galaxies, which may indicate a more relaxed cluster dynamical status, improves the agreement between the observed and simulated cluster mass and stellar mass of the central galaxy. We also find that at a given cluster mass the stellar mass of blue central galaxies is lower than that of the red ones.

The Next Generation Virgo Cluster Survey (NGVS). XXX. Ultra-diffuse Galaxies and Their Globular Cluster Systems

Abstract We present a study of ultra-diffuse galaxies (UDGs) in the Virgo Cluster based on deep imaging from the Next Generation Virgo Cluster Survey. Applying a new definition for the UDG class based on galaxy scaling relations, we define samples of 44 and 26 UDGs using expansive and restrictive selection criteria, respectively. Our UDG sample includes objects that are significantly fainter than previously known UDGs: i.e., more than half are fainter than mag arcsec−2. The UDGs in Virgo’s core region show some evidence for being structurally distinct from “normal” dwarf galaxies, but this separation disappears when considering the full sample of galaxies throughout the cluster. UDGs are more centrally concentrated in their spatial distribution than other Virgo galaxies of similar luminosity, while their morphologies demonstrate that at least some UDGs owe their diffuse nature to physical processes—such as tidal interactions or low-mass mergers—that are at play within the cluster environment. The globular cluster (GC) systems of Virgo UDGs have a wide range in specific frequency (S N ), with a higher mean S N than “normal” Virgo dwarfs, but a lower mean S N than Coma UDGs at fixed luminosity. Their GCs are predominantly blue, with a small contribution from red clusters in the more massive UDGs. The combined GC luminosity function is consistent with those observed in dwarf galaxies, showing no evidence of being anomalously luminous. The diversity in their morphologies and their GC properties suggests no single process has given rise to all objects within the UDG class. Based on the available evidence, we conclude that UDGs are simply those systems that occupy the extended tails of the galaxy size and surface brightness distributions.

WIYN Open Cluster Study. LXXXI. Caught in the Act? The Peculiar Red Giant NGC 2243-W2135

Abstract High-dispersion spectra for giants through turnoff stars in the Li 6708 Å region have been obtained and analyzed in the old, metal-deficient open cluster, NGC 2243. When combined with high-dispersion data from other surveys, the cluster is found to contain a uniquely peculiar star at the luminosity level of the red clump. The giant is the reddest star at its luminosity, exhibits variability at a minimum 0.1 mag level on a timescale of days, is a single-lined, radial-velocity variable, and has between 35 and 40 km s−1. In sharp contrast with the majority of the red giant cluster members, the star has a detectable Li abundance, potentially as high or higher than other giants observed to date while at or just below the boundary normally adopted for Li-rich giants. The observed anomalies may be indicators of the underlying process by which the giant has achieved its unusual Li abundance, with a recent mass transfer episode being the most probable within the currently limited constraints.

Contrasting Structure and Bonding of a Copper-Rich and a Zinc-Rich Intermetalloid Cu/Zn Cluster.

Reaction of the Cu(I) sources, [Cu5](Mes)5 and [(iDipp)CuOtBu] (Mes = mesityl; iDipp = 1,3-bis(2,6-diisopropylphenyl)-1H-imidazol-2-ylidene) with the Zn(I) complex [Zn2](Cp*)2 leads to a mixture of intermetallic Cu/Zn clusters with a distribution of species that is dependent on the stoichiometric ratio of the reactants, the reaction time, as well as the temperature. Systematic and careful investigation of the product mixtures rendered the isolation of two new clusters possible, i.e., the Zn-rich, red cluster 1, [CuZn10](Cp*)7 = [Cu(ZnZnCp*)3(ZnCp*)4], as well as the Cu-rich, dark-green cluster 2 [Cu10Zn2](Mes)6(Cp*)2. Structure and bonding of these two species was rationalized with the help of density functional theory calculations. Whereas 1 can be viewed as an 18-electron Cu center coordinated to four ZnCp* and three ZnZnCp* one-electron ligands (with some interligand bonding interaction), compound 2 is better to be described as a six-electron superatom cluster. This unusual electron count is associated with a prolate distortion from a spherical superatom structure. This unexpected situation is likely to be associated with the ZnCp* capping units that offer the possibility to strongly bind to the top and the bottom of the cluster in addition to the bridging mesityl ligands stabilizing the Cu core of the cluster.

Cadmium accumulation and migration of 3 peppers varieties in yellow and limestone soils under geochemical anomaly

ABSTRACT The high geological background of heavy metal cadmium (Cd) in geochemical anomaly areas in Southwest China and the anthropogenic pollution superposition effect in some typical areas due to mining exploitation have attracted special attention for several decades. The accumulation and migration of Cd in the farmland soil-crop system was worth discussing. In this study, the representative yellow soil and limestone soil in Guizhou Province, as well as three types of pepper (Capsicum annuum L.) were selected to investigate Cd accumulation and migration regulation from soil to plants using pot tests at different Cd concentration levels. For red cluster pepper, line pepper and hybrid pepper, the accumulation capacity of Cd in various parts was similar as follows: Cdroot > Cdstem ≈ Cdleaf > Cdfruit. The differences in the Cd concentration between pepper varieties were as follows: Cd in line pepper roots was higher than that in red cluster pepper and hybrid pepper, but for leaves and fruits, the Cd concentration of red cluster pepper was higher than the others. A higher accumulation and lower transport capacity of Cd in yellow soil as well as a lower accumulation and higher transport capacity of Cd in limestone soil were achieved based on the results of enrichment coefficients and transport coefficients in yellow soil. The red pepper Cd concentration was higher than that of the other two types. The accumulation and transformation of Cd for peppers in yellow soil is more significant (p < 0.05), which results in a higher risk of migration through the food chain.

CODEX clusters

Context. Large area catalogs of galaxy clusters constructed from ROSAT All-Sky Survey provide the basis for our knowledge of the population of clusters thanks to long-term multiwavelength efforts to follow up observations of these clusters. Aims. The advent of large area photometric surveys superseding previous, in-depth all-sky data allows us to revisit the construction of X-ray cluster catalogs, extending the study to lower cluster masses and higher redshifts and providing modeling of the selection function. Methods. We performed a wavelet detection of X-ray sources and made extensive simulations of the detection of clusters in the RASS data. We assigned an optical richness to each of the 24 788 detected X-ray sources in the 10 382 square degrees of the Baryon Oscillation Spectroscopic Survey area using red sequence cluster finder redMaPPer version 5.2 run on Sloan Digital Sky Survey photometry. We named this survey COnstrain Dark Energy with X-ray (CODEX) clusters. Results. We show that there is no obvious separation of sources on galaxy clusters and active galactic nuclei (AGN) based on the distribution of systems on their richness. This is a combination of an increasing number of galaxy groups and their selection via the identification of X-ray sources either by chance or by groups hosting an AGN. To clean the sample, we use a cut on the optical richness at the level corresponding to the 10% completeness of the survey and include it in the modeling of the cluster selection function. We present the X-ray catalog extending to a redshift of 0.6. Conclusions. The CODEX suvey is the first large area X-ray selected catalog of northern clusters reaching fluxes of 10−13 ergs s−1 cm−2. We provide modeling of the sample selection and discuss the redshift evolution of the high end of the X-ray luminosity function (XLF). Our results on z &lt; 0.3 XLF agree with previous studies, while we provide new constraints on the 0.3 &lt; z &lt; 0.6 XLF. We find a lack of strong redshift evolution of the XLF, provide exact modeling of the effect of low number statistics and AGN contamination, and present the resulting constraints on the flat ΛCDM.

Red, green, blue, and white clusters for daylight reproduction

Daylight is an inherent attribute of a sustainable building. Artificial reproduction of natural illumination under varying needs and environmental conditions has been made possible after the appearance of the new wave of solid-state light sources. Our work is devoted to the development of white light-emitting diode (LED) clusters consisting of red, green, blue, and white (RGBW) LEDs for implementation in a smart lighting system that is able to reproduce light with correlated color temperature (CCT) similar to daylight, high values of color rendering index, and luminous efficacy. A method for determination of the optimal contribution of each of the four LEDs is demonstrated and discussed. We show that only three LEDs—green, blue, and white (no red) can be used in many cases for reproducing daylight. Both luminous efficacy of radiation and actual luminous efficacy of the considered RGBW clusters as functions of the CCT are analyzed.

Iron oxide–Si nanoparticle magnetic core–shell induced by the interaction of d-orbitals of Fe2+ with reconstructed Si dimer-like defects

Redox-type charge exchange between Si nanoparticles and aqueous metal ions mx+ was recently used to synthesize core–shell nanocomposites in which their functionalities have been integrated. The process requires the electron (hole) affinities of the two to be different, with the efficiency of the charge exchange being strongly dependent on their difference. In this paper, we examine the interaction of Fe ions and red luminescent Si nanoparticles where the metal ion has comparable electron affinity to that of the Si nanoparticle. Scanning electron microscopy and fluorescent spectroscopy imaging show the formation of red luminescent core-shell clusters ranging from 100 nm to 500 nm. A permanent magnet is found to pull the structures indicating the formation of a magnetic phase. We use first principle atomistic computations at the unrestricted Hartree–Fock-DFT (density functional theory) level to obtain the charging energies and affinities of various ions of Fe and the Si nanoparticle. The computations indicate that Fe2+ cannot be oxidized to Fe3+ by the nanoparticle and it cannot strip one or two electrons from the nanoparticle and freely separate, resulting in bound complexes. Our analysis shows that a magnetic phase of iron oxide results from charge delocalization over the complex and a simultaneous interaction of the iron d-orbitals with the oxygen’s lone electrons and the nanoparticle’s reconstruction dimer-like defects. The core-shell integration at the nanoscale affords double functionality of luminescence and magnetism enhancing sensing, tracking, and delivery and enabling a variety of applications, including controlled drug delivery, underground oil and water exploration, and recovery.