The Size, Distribution, and Growth of the Texas Population, 1980-1990

The Size, Distribution, and Growth of the Texas Population, 1980-1990Bureau of Business Researc

The Size and Distribution of Two Minority Population Groups in Texas

The Size and Distribution of Two Minority Population Groups in TexasBureau of Business Researc

Characterization of the Active Site and Insight into the Binding Mode of the Anti-angiogenesis Agent Fumagillin to the Manganese(II)-Loaded Methionyl Aminopeptidase from \u3cem\u3eEscherichia coli\u3c/em\u3e

EPR spectra were recorded for methionine aminopeptidase from Escherichia coli (EcMetAP-I) samples (~2.5 mM) to which one and two equivalents of Mn(II) were added (the latter is referred to as [MnMn(EcMetAP-I)]). The spectra for each sample were indistinguishable except that the spectrum of [MnMn(EcMetAP-I)] was twice as intense. The EPR spectrum of [MnMn(EcMetAP-I)] exhibited the characteristic six-line g≈2 EPR signal of mononuclear Mn(II) with A av(55Mn)=9.3 mT (93 G) and exhibited Curie-law temperature dependence. This signal is typical of Mn(II) in a ligand sphere comprising oxygen and/or nitrogen atoms. Other features in the spectrum were observed only as the temperature was raised from that of liquid helium. The temperature dependences of these features are consistent with their assignment to excited state transitions in the S=1, 2 ... 5 non-Kramer’s doublets, due to two antiferromagnetically coupled Mn(II) ions with an S=0 ground state. This assignment is supported by the observation of a characteristic 4.5 mT hyperfine pattern, and by the presence of signals in the parallel mode consistent with a non-Kramers’ spin ladder. Upon the addition of the anti-angiogenesis agent fumagillin to [MnMn(EcMetAP-I)], very small changes were observed in the EPR spectrum. MALDI-TOF mass spectrometry indicated that fumagillin was, however, covalently coordinated to EcMetAP-I. Therefore, the inhibitory action of this anti-angiogenesis agent on EcMetAP-I appears to involve covalent binding to a polypeptide component at or near the active site rather than direct binding to the metal ions

Structural Characterization of Zn(II)-, Co(II)-, and Mn(II)-loaded Forms of the argE-encoded \u3cem\u3eN\u3c/em\u3e-acetyl-L-ornithine Deacetylase from \u3cem\u3eEscherichia coli\u3c/em\u3e

The Zn, Co, and Mn K-edge extended X-ray absorption fine structure (EXAFS) spectra of the N-acetyl-l-ornithine deacetylase (ArgE) from Escherichia coli, loaded with one or two equivalents of divalent metal ions (i.e., [Zn(II)_(ArgE)], [Zn(II)Zn(II)(ArgE)], [Co(II)_(ArgE)], [Co(II)Co(II)(ArgE)], [Mn(II)_(ArgE)], and [Mn(II)Mn(II)(ArgE)]), were recorded. The Fourier transformed data (FT) for [Zn(II)_(ArgE)], [Zn(II)Zn(II)(ArgE)], [Co(II)_(ArgE)] and [Co(II)Co(II)(ArgE)] are dominated by a peak at 2.05 Å, that can be fit assuming five or six light atom (N,O) scatterers. Inclusion of multiple-scattering contributions from the outer-shell atoms of a histidine-imidazole ring resulted in reasonable Debye–Waller factors for these contributions and a slight reduction in the goodness-of-fit value (f′). Furthermore, the data best fit a model that included a M–M vector at 3.3 and 3.4 Å for Zn(II) and Co(II), respectively, suggesting the formation of a dinuclear site. Multiple scattering contributions from the outer-shell atoms of a histidine-imidazole rings are observed at ~ 3 and 4 Å for Zn(II)- and Co(II)-loaded ArgE suggesting at least one histidine ligand at each metal binding site. Likewise, EXAFS data for Mn(II)-loaded ArgE are dominated by a peak at 2.19 Å that was best fit assuming six light atom (N,O) scatterers. Due to poor signal to noise ratios for the Mn EXAFS spectra, no Mn–Mn vector could be modeled. Peak intensities for [M(II)_(ArgE)] vs. [M(II)M(II)(ArgE)] suggest the Zn(II), Co(II), and Mn(II) bind to ArgE in a cooperative manner. Since no structural data has been reported for any ArgE enzyme, the EXAFS data reported herein represent the first structural glimpse for ArgE enzymes. These data also provide a structural foundation for the future design of small molecules that function as inhibitors of ArgE and may potentially function as a new class of antibiotics

Applying the Dark Target Aerosol Algorithm with Advanced Himawari Imager Observations During the KORUS-AQ Field Campaign

For nearly 2 decades we have been quantitatively observing the Earth's aerosol system from space at one or two times of the day by applying the Dark Target family of algorithms to polar-orbiting satellite sensors, particularly MODIS and VIIRS. With the launch of the Advanced Himawari Imager (AHI) and the Advanced Baseline Imagers (ABIs) into geosynchronous orbits, we have the new ability to expand temporal coverage of the traditional aerosol optical depth (AOD) to resolve the diurnal signature of aerosol loading during daylight hours. The KoreanUnited States Air Quality (KORUS-AQ) campaign taking place in and around the Korean peninsula during MayJune 2016 initiated a special processing of full-disk AHI observations that allowed us to make a preliminary adoption of Dark Target aerosol algorithms to the wavelengths and resolutions of AHI. Here,we describe the adaptation and show retrieval results from AHI for this 2-month period. The AHI-retrieved AOD is collocated in time and space with existing AErosol RObotic NETwork stations across Asia and with collocated Terra and Aqua MODIS retrievals. The new AHI AOD product matches AERONET, and the standard MODIS product does as well, and the agreement between AHI and MODIS retrieved AOD is excellent, as can be expected by maintaining consistency in algorithm architecture and most algorithm assumptions. Furthermore, we show that the new product approximates the AERONET-observed diurnal signature. Examining the diurnal patterns of the new AHI AOD product we find specific areas over land where the diurnal signal is spatially cohesive. For example, in Bangladesh the AOD in-creases by 0.50 from morning to evening, and in northeast China the AOD decreases by 0.25. However, over open ocean the observed diurnal cycle is driven by two artifacts, one associated with solar zenith angles greater than 70t hat may be caused by a radiative transfer model that does not properly represent the spherical Earth and the other artifact associated with the fringes of the 40 degree glint angle mask. This opportunity during KORUS-AQ provides encouragement to move towards an operational Dark Target algorithm for AHI. Future work will need to re-examine masking including snow mask, reevaluate assumed aerosol models for geosynchronous geometry, address the artifacts over the ocean, and investigate size parameter retrieval from the over-ocean algorithm

Photon Statistics Limits for Earth-Based Parallax Measurements of MACHO Events

We analyze the limitations imposed by photon counting statistics on extracting useful information about MACHOs from Earth-based parallax observations of microlensing events. We find that if one or more large (say $2.5\,\rm m$) telescopes are dedicated to observing a MACHO event for several nights near maximum amplification, then it is possible, in principle, to measure the velocity of the MACHO well enough to distinguish between disk and halo populations for events with \omega {A_m}\!^2 \gta 1\,\rm day^{-1}, where $\omega^{-1}$ denotes the timescale of the event and $A_m$ denotes its maximum amplification. Thus, if it turns out to be possible to reduce all other sources of error to below that of photon statistics, it may be feasible to do useful Earth-based parallax observations for high amplification events.Comment: 10 pages; LaTeX. one figure available upon request to [email protected]. REVISED: Error in impact parameter distribution of MACHO events (which had led to an underestimate of the expected fraction of high amplification events) was corrected; two references were added

Black hole shadows, photon rings, and lensing rings

The presence of a bright "photon ring" surrounding a dark "black hole shadow" has been discussed as an important feature of the observational appearance of emission originating near a black hole. We clarify the meaning and relevance of these heuristics with analytic calculations and numerical toy models. The standard usage of the term "shadow" describes the appearance of a black hole illuminated from all directions, including from behind the observer. A backlit black hole casts a somewhat larger shadow. Neither "shadow" heuristic is particularly relevant to understanding the appearance of emission originating near the black hole, where the emission profile and gravitational redshift play the dominant roles in determining the observed size of the central dark area. A photon ring results from light rays that orbit around the black hole in the near-field region before escaping to infinity, where they arrive near a ring-shaped "critical curve" on the image plane. Although the brightness can become arbitrarily large near this critical curve in the case of optically thin emitting matter near the black hole, we show that the enhancement is only logarithmic, and hence is of no relevance to present observations. For optically thin emission from a geometrically thin or thick disk, photons that make only a fraction of an orbit will generically give rise to a much wider "lensing ring," which is a demagnified image of the back of the disk, superimposed on top of the direct emission. For nearly face-on viewing, the lensing ring is centered at a radius similar to 5% larger than the photon ring and, depending on the details of the emission, its width is similar to 0.5-1M (where M is the mass of the black hole). It can be relatively brighter by a factor of 2-3, as compared to the surrounding parts of the image, and thus could provide a significant feature in high-resolution images. Nevertheless, the characteristic features of the observed image are dominated by the location and properties of the emitting matter near the black hole. We comment on the recent M87* Event Horizon Telescope observations and mass measurement.NSF [PHY-1505124, PHY-1804216, PHY-1752809, PHY-1708081]; Kavli Institute for Cosmological Physics at the University of Chicago through an endowment from the Kavli Foundation; Marion and Stuart Rice AwardThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]