The early-type galaxies NGC 1407 and NGC 1400 – II. Star formation and chemical evolutionary history

We present a possible star formation and chemical evolutionary history for two early-type galaxies NGC 1407 and NGC 1400. They are the two brightest galaxies of the NGC 1407 (or Eridanus-A) group, one of the 60 groups studied as part of the Group Evolution Multi-wavelength Study.
Our analysis is based on new high signal-to-noise ratio spatially resolved integrated spectra obtained at the ESO 3.6-m telescope, out to ∼0.6 (NGC 1407) and ∼1.3 (NGC 1400) effective radii. Using Lick/IDS indices, we estimate luminosity-weighted ages, metallicities and α-element abundance ratios. Colour radial distributions from HST /ACS and Subaru Suprime-Cam multiband wide-field imaging are compared to colours predicted from spectroscopically determined ages and metallicities using single stellar population (SSP) models. The galaxies formed over half of their mass in a single short-lived burst of star formation  (≥100 M_⊙ yr⁻¹)  at redshift z ≥ 5. This likely involved an outside–in mechanism with supernova-driven galactic winds, as suggested by the flatness of the α-element radial profiles and the strong negative metallicity gradients. Our results support the predictions of the revised version of the monolithic collapse model for galaxy formation and evolution. We speculate that, since formation, the galaxies have evolved quiescently and that we are witnessing the first infall of NGC 1400 in the group.     

The contribution of Very Long Baseline Interferometry to ITRF2005

The contribution of the International VLBI Service for Geodesy and Astrometry (IVS) to the ITRF2005 (International Terrestrial Reference Frame 2005) has been computed by the IVS Analysis Coordinator’s office at the Geodetic Institute of the University of Bonn, Germany. For this purpose the IVS Analysis Centres (ACs) provided datum-free normal equation matrices in Solution INdependent EXchange (SINEX) format for each 24 h observing session to be combined on a session-by-session basis by a stacking procedure. In this process, common sets of parameters, transformed to identical reference epochs and a prioris, and especially representative relative weights have been taken into account for each session. In order to assess the quality of the combined IVS files, Earth orientation parameters (EOPs) and scaling factors have been derived from the combined normal equation matrices. The agreement of the EOPs of the combined normal equation matrices with those of the individual ACs in terms of weighted root mean square (WRMS) is in the range of 50–60 μas for the two polar motion components and about 3 μs for UT1−UTC. External comparisons with International GNSS Serive (IGS) polar motion components is at the level of 130–170 μas and 21 μs/day for length of day (LOD). The scale of the terrestrial reference frame realized through the IVS SINEX files agrees with ITRF2000 at the level of 0.2 ppb.     

Geographic influences on sexual and reproductive health service utilization in rural Mozambique

The HIV/AIDS epidemic remains a major public health issue across the globe, and it is of particular concern in sub-Saharan Africa. Utilization of sexual and reproductive health (SRH) services can significantly impact HIV prevention, transmission, and treatment. SRH service utilization may be determined by individual characteristics, such as education and economic status, but also by the location and accessibility of health care facilities. Using population-based survey data, this study applies exploratory spatial analysis techniques to examine spatial patterns of SRH service utilization among rural married women in southern Mozambique. Clustering among those using services is found as are spatial associations, indicating significant spatial variability in the utilization of health services. The findings provide valuable insights for current and future health care program planning and configuration.     

The Australia Telescope 20-GHz (AT20G) Survey: the Bright Source Sample

The Australia Telescope 20-GHz (AT20G) Survey is a blind survey of the whole southern sky at 20 GHz (with follow-up observations at 4.8 and 8.6 GHz) carried out with the Australia Telescope Compact Array from 2004 to 2007.
The Bright Source Sample (BSS) is a complete flux-limited subsample of the AT20G Survey catalogue comprising 320 extragalactic     ) radio sources south of  δ=−15°  with      Jy. Of these, 218 have near simultaneous observations at 8 and 5 GHz.
In this paper we present an analysis of radio spectral properties in total intensity and polarization, size, optical identifications and redshift distribution of the BSS sources. The analysis of the spectral behaviour shows spectral curvature in most sources with spectral steepening that increases at higher frequencies (the median spectral index α, assuming   S ∝ν^α  , decreases from  α^8.6_4.8= 0.11  between 4.8 and 8.6 GHz to  α²⁰_8.6=−0.16  between 8.6 and 20 GHz), even if the sample is dominated by flat spectra sources (85 per cent of the sample has  α²⁰_8.6 > −0.5)  . The almost simultaneous spectra in total intensity and polarization allowed us a comparison of the polarized and total intensity spectra: polarized fraction slightly increases with frequency, but the shapes of the spectra have little correlation. Optical identifications provided an estimation of redshift for 186 sources with a median value of 1.20 and 0.13, respectively, for QSO and galaxies.     

Under the state's gaze: Upland trading‐scapes on the Sino‐Vietnamese border

Within the politically‐defined Greater Mekong Subregion (GMS), the borderlands of southeast Yunnan, China and Lào Cai province, northern Vietnam, have been categorized as being part of the GMS North‐South Economic Corridor. I argue that the creation of this subregion and corridor have been an opportunity for the governments in these locales to extend their territorialization and create new state spaces. For centuries, relatively isolated and ignored by lowland rulers, ethnic minority residents in these borderlands maintained their own culturally appropriate livelihoods, trade networks and societies. Nowadays, an increasing state presence in the uplands presents both challenges and opportunities for local populations on either side of the border, be they ethnic minorities, or Kinh (lowland Vietnamese) and Han Chinese. Contemporary border narratives gathered from local traders managing important upland commodities shed light on the means by which these borderland spaces are shaping both attractive prospects as well as restrictive constraints. Local residents fashion new trading‐scapes by drawing on kin ties, historical linkages, local indigenous knowledges and transnational societies that reach deep inside each country. As inhabitants carefully avoid or manipulate the state's gaze, I conclude that those living in the Sino‐Vietnamese borderlands possess the agency to ‘do things differently’ from hegemonic development approaches supported by GMS sponsors, and can create, maintain, support and refashion culturally appropriate trade livelihoods.     

Planning for Peri-urban Agriculture: a geographically-specific,evidence-based approach from Sydney

Agriculture on the fringes of cities across the Global North is increasingly perceived as making an important contribution to urban sustainability. As Australian cities continue to expand and encroach on their peri-urban peripheries, there is rising concern about loss of farmland to housing. Such concerns are especially urgent in the Sydney Basin, due to population growth, and topographical and land-use constraints. Accounting for the Basin's farmlands, however, remains opaque, not unrelated to difficulties in acquiring reliable data on the area and value of Sydney's agricultural industries. The problem is not simply that there are no data available but rather that the nature of existing data is (often hotly) contested. Critical questions for urban planners therefore remain unanswered, including: is peri-urban agriculture as important as advocates suggest? Are metropolitan food supplies under threat? If peri-urban farmland is important, what should be done to preserve it? In collating and analysing existing Australian Bureau of Statistics (ABS) and non-ABS data on Sydney agriculture between 1992 and 2011, we outline the need for more reliable and consistent longitudinal data to enable better planning for Sydney's farmland into the future. Notwithstanding limitations of available data sources, our findings reveal trends in Sydney Basin agriculture that invite debate on many assumptions about the nature of peri-urban agriculture. These findings emphasise the importance of geographically specific, evidence-based analysis as a basis for planning for peri-urban agriculture.     

Plio-Pleistocene microtephra in DSDP site 231, Gulf of Aden

We reconstruct a Plio-Pleistocene microscopic tephrostratigraphy for DSDP Site 231 in the Gulf of Aden. Systematic microtephrostratigraphy increases the potential for identifying tephra horizons for regional stratigraphic correlation and age control, as well as providing information about eruptive histories. Microtephra reveal three main pulses of volcanism c. 4.0–3.2 Ma, 2.4 Ma and 1.7–1.3 Ma, corresponding to peaks in volcanic activity recorded in the East African Rift System. Previous studies of DSDP Site 231 have reported six visible tephra horizons (up to 25 cm thick) with geochemical compositions matching East African tuffs. We find 68 additional microtephra horizons through microscopic examination of 1050 samples (each integrating c. 3 ka) in over 200 m of marine sediments. We report the major and minor element geochemical compositions of individual glass shards in six of these microtephra horizons and establish a robust correlation at 168.73 m to the Lokochot Tuff (3.58 Ma), which together with previously identified tephra, provides a tightly constrained chronostratigraphy for the mid Pliocene.     

Origin of post‐Minoan caves and volcaniclastic cave fill,Thera (Santorini), Greece

The Aegean island of Thera (Santorini) was covered by tephra from its cataclysmic Late Bronze Age (ca. 3600 yr B.P.) eruption. Vertical exposures of the eruptive sequence show secondary, nonvolcanic, circular (in cross section) features composed of stratified sediment. Many are inaccessible from the floors of modern quarries and appear to be caves filled with younger sediment, but show no connection to the land surface. A filled cave was found in the wall of a modern gully outside the modern quarries, and a filled cave was found in a terrace scarp, well above the modern gully. Natural (and probably rapid) incision by gullies into the thick tephra deposit left many locations with lateral access to tephra. Inhabitants from post‐Minoan to recent times excavated tephra for materials and buildings, and caves were subsequently filled by sporadic (possibly seasonal) flood events that deposited sediment. These gullies may have provided access for modern tephra removal that isolated the filled caves high on the modern quarry walls. © 2003 Wiley Periodicals, Inc.     

Thin section petrography of northern Lesser Antilles ceramics

Thin sections from 44 sherds representing eight prehistoric sites on four islands (Barbuda, Montserrat, Anguilla, St. Martin) in the northern Lesser Antilles (West Indies) were examined using a petrographic microscope. Point counting distinguished three temper associations: (1) exclusively volcanic,(2) volcanic and carbonate, and (3) volcanic, carbonate, and grog. Exclusively volcanic or dominantly volcanic (with low carbonate) temper associations occur in all Saladoid and many post-Saladoid sherds, with plagioclase feld-spar and volcanic rock fragments being most abundant. Thin sections with significant carbonate content or with grog were restricted to post-Saladoid sherds from Barbuda and to a lesser extent Anguilla. the presence of volcanic grains in sherds from the limestone islands of Barbuda and Anguilla indicates that volcanic islands in the region served as sources of pottery (or volcanic temper) for these two islands.