Reproductive periodicity in Evechinus chloroticus in the Hauraki Gulf

Test diameter and gonad volume were recorded over 1 year for bimonthly samples of Evechinus chloroticus (Valenciennes) from each of 3 subtidal populations 10 km apart in the Hauraki Gulf. Histological analysis was used to relate cellular events during gametogenesis to the annual cycle of change in gonad size. Mean gonad sizes of the different sea urchin populations were compared by analysis of covariance. Gametogenesis began in the spring, and major spawning occurred in mid to late summer. The proportion of the gonads taken up by nutritive phagocyte cells increased from autumn to spring. During proliferation and growth of gametes the nutritive phagocytes declined in abundance and globulation, suggesting that reserves stored in these cells were transferred to developing gametes. Gonad size doubled during gametogenesis, declined after spawning, and remained low in autumn and winter. Differences in gonad size between populations were significant during most of the year, and were most pronounced in mid summer. Although synchronous gametogenesis occurred in the 3 populations studied, spawning occurred at different times. This suggested that spawning in this species was induced by factors acting either within sea urchin populations or over distances of a few km or less.     

Recent geological advances concerning the H.Y.C. and associated deposits,McArthur river,N.Y.

Recent mineral exploration in the McArthur River District, Northern Territory, has found new areas of base‐metal mineralization and has resulted in a reinterpretation of the geological setting of the previously discovered mineral deposits. The geology along the eastern margin of the H.Y.C. sub‐basin has been revised. The Cooley Dolomite Member of the Barney Creek Formation is interpreted as a talus‐slope breccia lying adjacent to a syndepositionally uplifted fault block (Western Fault Block) of lower McArthur Group sediments. The Western Fault Block was the source of the majority of the fragments in breccia horizons in the H.Y.C. sub‐basin and its uplift played an important role in the development of the sub‐basin. Within the Western Fault Block, the sequence hosting the Cooley II copper mineralization is the Mara Dolomite Member of the Emmerugga Dolomite, and not the Cooley Dolomite Member of the Barney Creek Formation as previously thought. New mineral discoveries include the substantial extension of the Coxco deposit, a coarse‐grained zinc‐lead stratabound deposit showing affinities with the Mississippi Valley‐type deposits; and an area of stratiform fine‐grained zinc‐lead mineralization in the Emu Plains sub‐basin of the Bulburra Depression.     

Palaeomagnetic dating and stratigraphy of a Cainozoic lake near Cooma,N.S.W.

Palaeomagnetic dates for two sites on the Southern Tablelands of New South Wales, at Bunyan and Bredbo, indicate that basal lake sediments and underlying bedrock were ferruginised during the late Tertiary. The dates provide further evidence of a regional episode of intense weathering and ferruginisation in the late Tertiary.     

Secondary flow deflection in the lee of transverse dunes with implications for dune morphodynamics and migration

Measurements of lee‐side airflow response from an extensive array of meteorological instruments combined with smoke and flow streamer visualization is used to examine the development and morphodynamic significance of the lee‐side separation vortex over closely spaced transverse dune ridges. A differential deflection mechanism is presented that explains the three‐dimensional pattern of lee‐side airflow structure for a variety of incident flow angles. These flow patterns produce reversed, along‐dune, and deflected surface flow vectors in the lee that are inferred to result in net ‘lateral diversion’ of sand transport over one dune wavelength for incident angles as small as 10° from crest‐transverse (i.e. 80° from the crest line). This lateral displacement increases markedly with incident flow angle when expressed as the absolute value of the total deflection in degrees. Reversed and multi‐directional flow occurs for incident angles between 90° and 50°. These results document the three‐dimensional nature of flow and sand transport over transverse dunes and provide empirical evidence for an oblique migration model. Copyright © 2013 John Wiley & Sons, Ltd.     

Geomorphic and sediment volume responses of a coastal dune complex following invasive vegetation removal

This paper documents application of an established geostatistical methodology to detect significant changes in a foredune–transgressive dune complex where Parks Canada Agency (PCA) implemented a dynamic restoration program to remove invasive marram grasses (Ammophila spp.) and enhance dynamic dune habitat for an endangered species. Detailed topographic surveys of a 10 320 m² site in the Wickaninnish Dunes in Pacific Rim National Park, British Columbia, Canada for the first year post‐treatment are compared to a pre‐restoration LiDAR baseline survey. The method incorporates inherent spatial structure in measured elevation datasets at the sub‐landscape scale and models statistically significant change surfaces within distinct, linked geomorphic units (beach, foredune, transgressive dune complex). Seasonal and annual responses within the complex are discussed and interpreted. All geomorphic units experienced positive sediment budgets following restoration treatment. The beach experienced the highest differential volumetric change (+1656 m³) and net sediment influx (+834 m³, 0 · 19 m³ m^–2) mostly from supply to the supratidal beach and incipient dune. This sediment influx occurred independent of the restoration effort and was available as a buffer against wave erosion and as supply to the landward dunes. The foredune received +200 m³ (0 · 13 m³ m^‐2) and its seaward profile returned to a similar pre‐restoration form following erosion at the crest from vegetation removal and scarping by high water events. Sediment bypassing and minimal change was evident at the mid‐stoss slope with appreciable extension of depositional lobes in the lee. The transgressive dune complex experienced high accretion following restoration activity (+201 m³) and over the year (+284 m³, 0 · 07 m³ m^–2) mostly from depositional lobes from the foredune, precipitation ridge growth along the downwind boundary, and growth of existing lobes within the complex. Further integration of this methodology to detect significant geomorphic changes is recommended, particularly for applications where sampling densities are limited or logistically defined. Copyright © 2013 John Wiley & Sons, Ltd.     

Immigration,local policy,and national identity in the suburban United States

Since 2000, the American suburb has emerged as a principal destination for new immigrants to the United States, both documented and undocumented. Whereas some suburban communities have responded to perceived undocumented immigrants with hostility in the form of exclusionary local immigration policies, others have introduced policies designed to welcome immigrants independent of federal legal status. In this article, I employ a qualitative comparative case study analysis of four local immigration policies in the Chicago and Washington DC metropolitan areas to explain how suburbs justify their policy positions. I find that these suburban communities relied on conceptions of American identity and the ‘American Dream’ in support of their policies, but leveraged these tropes in vastly different ways depending on the broader strategic purposes of the policies. These divergent suburban immigration policies both challenge traditional notions of suburban political and cultural homogeneity and reveal how such heterogeneity has produced a distinct unevenness in contemporary local policy responses to undocumented immigration within metropolitan regions.     

The Pen or the Sword: A Situated Spatial Analysis of Graffiti and Violent Injury in Vancouver,British Columbia

Graffiti is a ubiquitous feature of the urban landscape commonly perceived to be a symptom of disorder, deprivation, and violence. Broken windows theory asserts that it is also a cause. To examine this, we conduct a geographic correlation study of graffiti and violence using geographic information systems. A strong spatial covariation is observed, with spatially dependent residual clusters suggesting that the graffiti–violence relationship is context dependent and varied. Ferrell and Weide's spot theory provides a lens for situating hot spots and facilitating a more nuanced interrogation of graffiti and violence in several Vancouver neighborhoods. We advocate for situated spatial analyses of interpersonal violence to inform public health interventions and advance policymaking beyond the popular aesthetic symbolism of urban space.     

The Large Magellanic Cloud and the distance scale

The Magellanic Clouds, especially the Large Magellanic Cloud, are places where multiple distance indicators can be compared with each other in a straight-forward manner at considerable precision. We here review the distances derived from Cepheids, Red Variables, RR Lyraes, Red Clump Stars and Eclipsing Binaries, and show that the results from these distance indicators generally agree to within their errors, and the distance modulus to the Large Magellanic Cloud appears to be defined to ±3% with a mean value (m−M)₀=18.48 mag, corresponding to 49.7 kpc. The utility of the Magellanic Clouds in constructing and testing the distance scale will remain as we move into the era of Gaia.     

Episodic recharge and climate change in the Murray-Darling Basin, Australia

In semi-arid areas, episodic recharge can form a significant part of overall recharge, dependant upon infrequent rainfall events. With climate change projections suggesting changes in future rainfall magnitude and intensity, groundwater recharge in semi-arid areas is likely to be affected disproportionately by climate change. This study sought to investigate projected changes in episodic recharge in arid areas of the Murray-Darling Basin, Australia, using three global warming scenarios from 15 different global climate models (GCMs) for a 2030 climate. Two metrics were used to investigate episodic recharge: at the annual scale the coefficient of variation was used, and at the daily scale the proportion of recharge in the highest 1% of daily recharge. The metrics were proportional to each other but were inconclusive as to whether episodic recharge was to increase or decrease in this environment; this is not a surprising result considering the spread in recharge projections from the 45 scenarios. The results showed that the change in the low probability of exceedance rainfall events was a better predictor of the change in total recharge than the change in total rainfall, which has implications for the selection of GCMs used in impact studies and the way GCM results are downscaled.