Dispersive Liquid–Liquid Microextraction for Preconcentration and Determination of Nickel in Water

A method for the determination of nickel in water was developed. The procedure involves preconcentration of nickel by using dispersive liquid–liquid microextraction. The Ni(II) ions were extracted in chloroform in the form of complex with the reagent 2‐(2′‐benzothiazolylazo)‐p‐cresol. Ethanol was used as the disperser solvent. After injection of the extracting mixture in a solution of nickel, a cloudy mixture was observed. A quick centrifugation induces phase separation and thus the settling of rich phase. The nickel content in the rich phase is measured by flame atomic absorption spectrometry. Under optimal conditions, the limit of detection and quantification obtained were 1.4 and 4.7 µg L^?1, respectively. Some parameters used to characterize preconcentration systems, such as enrichment factor and consumption index were calculated and resulted in 29 and 0.34 mL, respectively. After optimization of variables and determination of analytical characteristics, the method was used for the analysis of certified reference materials (BCR‐713: wastewater, effluent and BCR‐414: plankton) and real water samples.     

A late Pleistocene record of aeolian sedimentation in Blanche Cave, Naracoorte, South Australia

We provide geochemical analyses and grain size data for a clearly layered, 80 cm thick sedimentary deposit close to a roof collapse in Blanche Cave near Naracoorte in SE South Australia. This deposit contains aeolian material deposited between 40 ka and 14 ka cal BP and which yields airborne sediments spanning the Last Glacial Maximum, a period of time with little information for the Australian continent. The deposit also contains abundant vertebrate fossil material derived from owl pellets, accumulation and pitfall entrapment. Below the studied profile, large vertebrate remains are found but are not discussed here. No Holocene sedimentation occurred at the site examined in the cave, and the top of the sequence is capped with a layer that has been anthropologically disturbed and contains exotic Pinus pollen. Chronologies of the deposit were obtained using two dating techniques: single stage accelerator mass spectrometer (SSAMS) ¹⁴C analysis of 23 charcoal samples and optically stimulated luminescence (OSL) dating of quartz from 6 sediment samples. The ¹⁴C chronology is preferred to describe the history of the deposits since the OSL chronology, which consistently overestimates the associated radiocarbon dates, may be inaccurate due to complexities in calculating dose rates, and may in addition represent the timing of sediment deposition through the cave opening rather than sediment transport to the deposit site. Morphological analysis of single quartz grains and grain size analysis indicate different provenance that is confirmed through the geochemical analyses of bulk sediment. Major elements were measured by X-ray Fluorescence (XRF), trace and rare earth elements by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA ICP-MS), and Neodymium isotopic ratios were obtained using a Thermal Ionisation Mass Spectrometer (TIMS).Our results indicate that the aeolian material deposited in Blanche Cave over the 40–14 ka cal BP period originated from different sources across South Australia, although Nd isotopes clearly indicate a close association with sediments of the Kanmantoo Group outcropping along the eastern portion of the Mount Lofty Ranges and the Padthaway Ridge further south, both being located to the NW and NNW of the cave. During the latter part of Marine Isotope Stage 3, conditions were wetter and windblown sediment came from the coastal region just north and south of the Coorong Lagoon, with winds originating from the north-northwest. At that time, woody taxa appear to have vegetated the landscape. During the drier phases, especially the Last Glacial Maximum, sediment came from further inland, thus suggesting a different predominant wind direction, more from the northwest. The deglaciation saw material originating from a more northerly direction.     

T—lnP图的制作及一些稳定度指数不稳定能量的计算

本文对T－lnP图（即埃玛图）的制作及一些稳定度指数和不稳定能量的计算进行了较为详细的说明，并进行了实际验证，表明用计算机进行温度对数压力图的制作，不仅方便快捷准确，而且能避免人为的误差。     

Is counselling a feminist practice?

Women’s efforts to influence policies have complex effects, which are often difficult to evaluate. This paper identifies four themes in feminist politics through which to analyse whether a particular intervention involving substantial numbers of women – that of counselling in the UK – can be understood as a feminist practice. These themes are concerned with gender equality, women’s autonomy, recognition of diversity among women and the deconstruction of gender norms. In its early post-war origins prior to the emergence of second wave feminism, and in the stories recounted by women practitioners at the turn of millennium, counselling emerges as contradictory and ambivalent in relation to these themes in feminist politics.     

Gender and hunger: salvaging essential categories

Summary This paper examines recent debates in development discourse and their implications for analyses of gender and hunger. It recognizes the insights that postist approaches offer, but finds that they too have dangers. It concludes that traditional perspectives and the categories these employ require revision rather than rejection.     

Hybrid stochastic-mechanical modeling of precipitation thresholds of shallow landslide initiation

Natural Hazards - International and domestic tourism is a growing industry in Costa Rica, with the most attractive places located along the coast. Despite their beauty, Costa Rican beaches can pose...     

Palestinians and pragmatic citizenship: Negotiating relationships between citizenship and national identity in diaspora

This paper puts forward the notion of pragmatic citizenship and forms part of the ongoing re-appraisals of citizenship in relation to national identity in an attempt to make it more relevant and inclusive for those with complex identities, legal status and, in particular, the stateless. Using the case study of Palestinians in Athens to discuss relationships between citizenship, identity and statehood, this paper argues that the notion of pragmatic citizenship can be useful in such re-conceptualisations as it can take into account the potentially ambivalent and multiple feelings of belonging that migrants and those in diaspora may have. In the process it stresses that strong notions of belonging and attachment to a territorialised homeland do not have to be exclusive or problematic. The paper outlines the complexity of Palestinian legal status in Athens and the feelings of injustice statelessness can provoke; it then describes the process of Palestinian acquisition of pragmatic citizenship in Greece. However, the final section of the paper highlights that such a notion of citizenship can have positive repercussions in terms of inclusive visions of a future one-state solution to the Palestinian-Israeli conflict.     

Rapid invertebrate responses to macroalgal wrack: two novel field experiments on intertidal mudflats in Southern Australia

Macroalgal wrack deposition along coasts is highly variable but it plays an important role in the structure and function of marine communities. To date, most research has focused on the effects of decomposing wrack as it assimilates into the system but little is known about the immediate effects of wrack when it is first deposited in the habitat. Freshly deposited wrack may either wash away after a short period (1–2 days) or remain in the habitat and decay depending on tide and weather conditions. To understand the effects of this dynamic resource we experimentally manipulated wrack deposits on intertidal mudflats in Port Phillip Bay, Victoria, Australia. We conducted two experiments using defaunated patches of wrack (300 g wet weight) that were a mixture of seagrass and macroalgae and measured community responses after 2 days. The first experiment included real and artificial wrack patches to differentiate between taxa that responded to the biological and physical structure of the wrack. The second experiment used multiple wrack patches to investigate responses to a focal wrack patch that was surrounded by varying numbers of wrack additional patches (0, 2 or 4 × 300 g wet weight of wrack). Overall, wrack increased abundances of invertebrates and changed their distributions throughout the wrack and underlying sediment habitat. Mechanisms responsible for immediate taxa responses to the wrack related to the physical structure in the habitat and not biological attributes associated with the real patches. Ostracods and leptostracans were the exception to these patterns with colonization only occurring in real wrack and not the artificial wrack. In the multiple patch experiment the majority of the fauna moved vertically into the wrack from the bare sediment and not between surrounding patches of wrack. We suggest that specific characteristics, such as invertebrate mobility, feeding mode and sensitivity to changes in sediment condition, are important factors that influence individual taxa and overall community responses. Understanding the interactive effects of these characteristics with the characteristics of the wrack (magnitude, frequency, spatial arrangement and composition) is the key to developing predictive models that will inform the management of wrack in marine coastal habitats.