Armed forces strong enough to protect the state also pose a threat to the state. We develop a model that distills this “Guardianship Dilemma” to its barest essentials, and show that the seemingly ...ironclad logic underlying our existing understanding of civil-military relations is flawed. Militaries contemplating disloyalty must worry about both successfully overthrowing the government and defeating the state’s opponent. This twin challenge induces loyalty as the state faces increasingly strong external threats, and can be managed effectively by rulers using a number of policy levers. Disloyalty can still occur when political and military elites hold divergent beliefs about the threat environment facing the state, since militaries will sometimes have less incentive to remain loyal than the ruler suspects. Consequently, it is not the need to respond to external threats that raises the risk of disloyalty—as conventional wisdom suggests—but rather uncertainty about the severity of these threats.
Context. The Sloan Digital Sky Survey (SDSS) and Wide-field Infrared Survey Explorer (WISE) provide information about the surface composition of about 100 000 minor planets. The resulting visible ...colors and albedos enabled us to group them in several major classes, which are a simplified view of the diversity shown by the few existing spectra. A large set of data in the 0.8−2.5 μm, where wide spectral features are expected, is required to refine and complement the global picture of these small bodies of the solar system. Aims. We aim to obtain the near-infrared colors for a large sample of solar system objects using the observations made during the VISTA-VHS survey. Methods. We performed a serendipitous search in VISTA-VHS observations using a pipeline developed to retrieve and process the data that corresponds to solar system objects (SSo). The resulting photometric data is analyzed using color−color plots and by comparison with the known spectral properties of asteroids. Results. The colors and the magnitudes of the minor planets observed by the VISTA survey are compiled into three catalogs that are available online: the detections catalog (MOVIS-D), the magnitudes catalog (MOVIS-M), and the colors catalog (MOVIS-C). They were built using the third data release of the survey (VISTA VHS-DR3). A total of 39 947 objects were detected, including 52 NEAs, 325 Mars Crossers, 515 Hungaria asteroids, 38 428 main-belt asteroids, 146 Cybele asteroids, 147 Hilda asteroids, 270 Trojans, 13 comets, 12 Kuiper Belt objects and Neptune with its four satellites. The colors found for asteroids with known spectral properties reveal well-defined patterns corresponding to different mineralogies. The distributions of MOVIS-C data in color−color plots shows clusters identified with different taxonomic types. All the diagrams that use (Y − J) color separate the spectral classes more effectively than the (J − H) and (H − Ks) plots used until now: even for large color errors (<0.1), the plots (Y − J) vs. (Y − Ks) and (Y − J) vs. (J − Ks) provide the separation between S-complex and C-complex. The end members A, D, R, and V-types occupy well-defined regions.
The UKIRT Infrared Deep Sky Survey (UKIDSS) Lawrence, A.; Warren, S. J.; Almaini, O. ...
Monthly notices of the Royal Astronomical Society,
08/2007, Letnik:
379, Številka:
4
Journal Article
Recenzirano
Odprti dostop
We describe the goals, design, implementation, and initial progress of the UKIRT Infrared Deep Sky Survey (UKIDSS), a seven-year sky survey which began in 2005 May. UKIDSS is being carried out using ...the UKIRT Wide Field Camera (WFCAM), which has the largest étendue of any infrared astronomical instrument to date. It is a portfolio of five survey components covering various combinations of the filter set ZYJHK and H2. The Large Area Survey, the Galactic Clusters Survey, and the Galactic Plane Survey cover approximately 7000 deg2 to a depth of K∼ 18; the Deep Extragalactic Survey covers 35 deg2 to K∼ 21, and the Ultra Deep Survey covers 0.77 deg2 to K∼ 23. Summed together UKIDSS is 12 times larger in effective volume than the 2MASS survey. The prime aim of UKIDSS is to provide a long-term astronomical legacy data base; the design is, however, driven by a series of specific goals – for example, to find the nearest and faintest substellar objects, to discover Population II brown dwarfs, if they exist, to determine the substellar mass function, to break the z= 7 quasar barrier; to determine the epoch of re-ionization, to measure the growth of structure from z= 3 to the present day, to determine the epoch of spheroid formation, and to map the Milky Way through the dust, to several kpc. The survey data are being uniformly processed. Images and catalogues are being made available through a fully queryable user interface – the WFCAM Science Archive (http://surveys.roe.ac.uk/wsa). The data are being released in stages. The data are immediately public to astronomers in all ESO member states, and available to the world after 18 months. Before the formal survey began, UKIRT and the UKIDSS consortia collaborated in obtaining and analysing a series of small science verification (SV) projects to complete the commissioning of the camera. We show some results from these SV projects in order to demonstrate the likely power of the eventual complete survey. Finally, using the data from the First Data Release, we assess how well UKIDSS is meeting its design targets so far.
X-ray properties of z ≳ 6.5 quasars Pons, E; McMahon, R G; Banerji, M ...
Monthly notices of the Royal Astronomical Society,
01/2020, Letnik:
491, Številka:
3
Journal Article
Recenzirano
Odprti dostop
ABSTRACT
We present XMM–Newton X-ray observations and analysis of three Dark Energy Survey z > 6.5 quasars (VDES J0020−3653 at z = 6.824, VDES J0244−5008 at z = 6.724, and VDES J0224−4711 at z = ...6.526) and six other quasars with 6.438 < z < 6.747 from the XMM–Newton public archive. Two of the nine quasars are detected at a high (>4σ) significance level: VDES J0224−4711(z = 6.53) at 9σ and PSO J159−02 (z = 6.38) at 8σ. They have a photon index of $\Gamma =1.82^{+0.29}_{-0.27}$ and $1.94^{+0.31}_{-0.29}$, respectively, which is consistent with the mean value of ∼1.9 found for quasars at all redshifts. The rest-frame 2–10 keV luminosity of VDES J0224−4711 is $L_{2\!-\!10\, \mathrm{keV}} = (2.92\pm 0.43)\times 10^{45}\,\mathrm{erg\,s^{-1}}$, which makes this quasar one of the most X-ray luminous quasars at z > 5.5 and the most X-ray luminous quasar at z > 6.5, with a luminosity 6 times and 2.5 times larger than ULAS J1120+0641 (z = 7.08) and ULAS J1342+0928 (z = 7.54), respectively. The X-ray-to-optical power-law slopes of the nine quasars are consistent with the previously observed anticorrelation of αox with UV luminosity $L_{2500\, \mathrm{\mathring{\rm A} }}$. We find no evidence for evolution of αox with redshift when the anticorrelation with UV luminosity is taken into account. Similar to previous studies at z ∼ 6, we have found remarkably consistent X-ray spectral properties between low-redshift quasars (z ∼ 1) and high-redshift quasars. Our results add further evidence to the picture that the observable properties of high-luminosity quasars over the UV-to-X-ray spectral region have not evolved significantly from z ∼ 7 to the present day and that quasars comparable to local versions existed 800 Myr after the big bang.
Radiation therapy is an established and effective anti-cancer treatment modality. Extensive pre-clinical experimentation has demonstrated that the pro-inflammatory properties of irradiation may be ...synergistic with checkpoint immunotherapy. Radiation induces double-stranded DNA breaks (dsDNA). Sensing of the dsDNA activates the cGAS/STING pathway, producing Type 1 interferons essential to recruiting antigen-presenting cells (APCs). Radiation promotes cytotoxic CD8 T-cell recruitment by releasing tumour-associated antigens captured and cross-presented by surveying antigen-presenting cells. Radiation-induced vascular normalisation may further promote T-cell trafficking and drug delivery. Radiation is also immunosuppressive. Recruitment of regulatory T cells (Tregs) and innate cells such as myeloid-derived suppressive cells (m-MDSCs) all counteract the immunostimulatory properties of radiation. Many innate immune cell types operate at the interface of the adaptive immune response. Innate immune cells, such as m-MDSCs, can exert their immunosuppressive effects by expressing immune checkpoints such as PD-L1, further highlighting the potential of combined radiation and checkpoint immunotherapy. Several early-phase clinical studies investigating the combination of radiation and immunotherapy have been disappointing. A greater appreciation of radiotherapy's impact on the innate immune system is essential to optimise radioimmunotherapy combinations. This review will summarise the impact of radiotherapy on crucial cells of the innate immune system and vital immunosuppressive cytokines.
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 Asymptotically = to 6.4, a limit set by the use of the z-band and CCD detectors. Only one z gap 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 gap 6.4 quasars in 332 deg super(2) 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) x 10 super(9) M sub(middot in circle). 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 rho(M sub(BH) > 10 super(9) M sub(middot in circle)) > 1.1 x 10 super(-9) Mpc super(-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.
Selected indole-based kratom alkaloids were evaluated for their opioid and adrenergic receptor binding and functional effects, in vivo antinociceptive effects, plasma protein binding, and metabolic ...stability. Mitragynine, the major alkaloid in Mitragyna speciosa (kratom), had higher affinity at opioid receptors than at adrenergic receptors while the vice versa was observed for corynantheidine. The observed polypharmacology of kratom alkaloids may support its utilization to treat opioid use disorder and withdrawal.
We report the discovery and monitoring of the near-infrared counterpart (AT2017gfo) of a binary neutron-star merger event detected as a gravitational wave source by Advanced Laser Interferometer ...Gravitational-wave Observatory (LIGO)/Virgo (GW170817) and as a short gamma-ray burst by Fermi Gamma-ray Burst Monitor (GBM) and Integral SPI-ACS (GRB 170817A). The evolution of the transient light is consistent with predictions for the behavior of a "kilonova/macronova" powered by the radioactive decay of massive neutron-rich nuclides created via r-process nucleosynthesis in the neutron-star ejecta. In particular, evidence for this scenario is found from broad features seen in Hubble Space Telescope infrared spectroscopy, similar to those predicted for lanthanide-dominated ejecta, and the much slower evolution in the near-infrared K s -band compared to the optical. This indicates that the late-time light is dominated by high-opacity lanthanide-rich ejecta, suggesting nucleosynthesis to the third r-process peak (atomic masses A 195 ). This discovery confirms that neutron-star mergers produce kilo-/macronovae and that they are at least a major-if not the dominant-site of rapid neutron capture nucleosynthesis in the universe.
ABSTRACT
We report the spectroscopic follow-up of 175 lensed quasar candidates selected using Gaia Data Release 2 observations following Paper III of this series. Systems include 86 confirmed lensed ...quasars and a further 17 likely lensed quasars based on imaging and/or similar spectra. We also confirm 11 projected quasar pairs and 11 physical quasar pairs, while 25 systems are left as unclassified quasar pairs – pairs of quasars at the same redshift, which could be either distinct quasars or potential lensed quasars. Especially interesting objects include eight quadruply imaged quasars of which two have BAL sources, an apparent triple, and a doubly lensed LoBaL quasar. The source redshifts and image separations of these new lenses range between 0.65–3.59 and 0.78–6.23 arcsec, respectively. We compare the known population of lensed quasars to an updated mock catalogue at image separations between 1 and 4 arcsec, showing a very good match at z < 1.5. At z > 1.5, only 47 per cent of the predicted number are known, with 56 per cent of these missing lenses at image separations below 1.5 arcsec. The missing higher redshift, small-separation systems will have fainter lensing galaxies, and are partially explained by the unclassified quasar pairs and likely lenses presented in this work, which require deeper imaging. Of the 11 new reported projected quasar pairs, 5 have impact parameters below 10 kpc, almost tripling the number of such systems, which can probe the innermost regions of quasar host galaxies through absorption studies. We also report four new lensed galaxies discovered through our searches, with source redshifts ranging from 0.62 to 2.79.
PDF
