Excited state intramolecular proton transfer in hydroxyanthraquinones: Toward predicting fading of organic red colorants in art.

Compositionally similar organic red colorants in the anthraquinone family, whose photodegradation can cause irreversible color and stability changes, have long been used in works of art. Different organic reds, and their multiple chromophores, suffer degradation disparately. Understanding the details of these molecules' degradation therefore provides a window into their behavior in works of art and may assist the development of improved conservation methods. According to one proposed model of photodegradation dynamics, intramolecular proton transfer provides a kinetically favored decay pathway in some photoexcited chromophores, preventing degradation-promoting electron transfer (ET). To further test this model, we measured excited state lifetimes of substituted gas-phase anthraquinones using high-level theory to explain the experimental results. The data show a general structural trend: Anthraquinones with 1,4-OH substitution are long-lived and prone to damaging ET, while excited state intramolecular proton transfers promote efficient quenching for hydroxyanthraquinones that lack this motif

The homotopy of Гq and classifying spaces

Let γ≥1 and Гq ^ be the topological groupoid of germs or orientation preserving local C(^v) diffeomorphisms of/R(^z). Then a E(^2) spectral sequence is constructed with the E(^2) terms computed from the homological properties of Г(_2), and E(^oo) is the bigraded module associated to the filtration of the homology of the classifying space, BГ given by Haefliger in [HA3]. Let S≥1 and Δ - rr [1,2,.....S+1] be the objects of the category C(_Δ)s with morphisms ≤ and Ѓ(_2)(Δ(^s) the space of functors from C(_Δ)-s to Г(_2) with the usual topology on Ѓ(_q). We prove that a) H(_t)(Ѓ(_q)(Δ(^s))(A')) = 0 for t > q. b) If Gl(_2) is the group of linear transformations of R(^2) with positive determinant then if V: Ѓ(_2)(Δ(^s))→(Gl(_2))(^s) is the map obtained by taking derivatives of ɤ (1 ≤ i) for 2 ≤ i ≤ s +1, ɤϵЃ(_2) is an isomorphism for t <q. These calculations go a long way towards calculating the E(^2) terms of the above spectral sequence. The spectral sequence is constructed for a large class of topological groupoids referred to as well formed topological groupoids, and the corresponding theorem on the high dimensional homologies of topological groupoids is proved for a special class of well formed topological groupoids which include the known topological groupoids associated with foliations

The social geography of unmarried cohabitation in the USA, 2007-2011

US studies of marriage and cohabitation have mainly highlighted the social and racial differentials as they were observed in cross-sections, and have as a result essentially focused on the "pattern of disadvantage". The evolution of such social differentials over time and space reveals that this pattern of disadvantage has clearly persisted, but that it is far from covering the whole story. Historically, there has been a major contribution to the rise of cohabitation by white college students, and later on young white adults with higher education continued to start unions via cohabitation to ever increasing degrees. Only, they seem to move into marriage to a greater extent later on in life than other population segments. Also, the religious affiliation matters greatly: Mormons and evangelical Christians have resisted the current trends. Furthermore this effect is not only operating at the individual but at the contextual level as well. Conversely, even after controls for competing socio-economic explanations, residence in areas (either counties or PUMA-areas) with a Democratic voting pattern is related to higher cohabitation probabilities. And, finally, different legal contexts at the level of States also significantly contributed to the emergence of strong spatial contrasts. Hence, there is a concurrence of several factors shaping the present differentiations, and the rise of secular and liberal attitudes, i.e. the "ethics revolution", is equally a part of the explanation

Genetic determinants of co-accessible chromatin regions in activated T cells across humans.

Over 90% of genetic variants associated with complex human traits map to non-coding regions, but little is understood about how they modulate gene regulation in health and disease. One possible mechanism is that genetic variants affect the activity of one or more cis-regulatory elements leading to gene expression variation in specific cell types. To identify such cases, we analyzed ATAC-seq and RNA-seq profiles from stimulated primary CD4+ T cells in up to 105 healthy donors. We found that regions of accessible chromatin (ATAC-peaks) are co-accessible at kilobase and megabase resolution, consistent with the three-dimensional chromatin organization measured by in situ Hi-C in T cells. Fifteen percent of genetic variants located within ATAC-peaks affected the accessibility of the corresponding peak (local-ATAC-QTLs). Local-ATAC-QTLs have the largest effects on co-accessible peaks, are associated with gene expression and are enriched for autoimmune disease variants. Our results provide insights into how natural genetic variants modulate cis-regulatory elements, in isolation or in concert, to influence gene expression

A search for point sources of EeV photons

Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Reconstruction of inclined air showers detected with the Pierre Auger Observatory

We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than $60^\circ$ detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.Comment: 27 pages, 19 figures, accepted for publication in Journal of Cosmology and Astroparticle Physics (JCAP

Azimuthal asymmetry in the risetime of the surface detector signals of the Pierre Auger Observatory

The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, $(\sec \theta)_\mathrm{max}$, sensitive to the mass composition of cosmic rays above $3 \times 10^{18}$ eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modelling that must be resolved before the mass composition can be inferred from $(\sec \theta)_\mathrm{max}$.Comment: Replaced with published version. Added journal reference and DO

The Pierre Auger Observatory: Contributions to the 34th International Cosmic Ray Conference (ICRC 2015)

Contributions of the Pierre Auger Collaboration to the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The NetherlandsComment: 24 proceedings, the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands; will appear in PoS(ICRC2015