High-resolution 14C dating of a 25,000-year lake-sediment record from equatorial East Africa

We dated a continuous, ~22-m long sediment sequence from Lake Challa (Mt. Kilimanjaro area, Kenya/Tanzania) to produce a solid chronological framework for multi-proxy reconstructions of climate and environmental change in equatorial East Africa over the past 25,000 years. The age model is based on a total of 168 AMS 14C dates on bulk-organic matter, combined with a 210Pb chronology for recent sediments and corrected for a variable old-carbon age offset. This offset was estimated by i) pairing bulk-organic 14C dates with either 210Pb-derived time markers or 14C dates on grass charcoal, and ii) wiggle-matching high-density series of bulk-organic 14C dates. Variation in the old-carbon age offset through time is relatively modest, ranging from ~450 yr during glacial and late glacial time to ~200 yr during the early and mid-Holocene, and increasing again to ~250 yr today. The screened and corrected 14C dates were calibrated sequentially, statistically constrained by their stratigraphical order. As a result their constrained calendar-age distributions are much narrower, and the calibrated dates more precise, than if each 14C date had been calibrated on its own. The smooth-spline age-depth model has 95% age uncertainty ranges of ~50–230 yr during the Holocene and ~250–550 yr in the glacial section of the record. The d13C values of paired bulk-organic and grass-charcoal samples, and additional 14C dating on selected turbidite horizons, indicates that the old-carbon age offset in Lake Challa is caused by a variable contribution of old terrestrial organic matter eroded from soils, and controlled mainly by changes in vegetation cover within the crater basin.

Current methods and advances in forecasting of wind power generation

Wind power generation differs from conventional thermal generation due to the stochastic nature of wind. Thus wind power forecasting plays a key role in dealing with the challenges of balancing supply and demand in any electricity system, given the uncertainty associated with the wind farm power output. Accurate wind power forecasting reduces the need for additional balancing energy and reserve power to integrate wind power. Wind power forecasting tools enable better dispatch, scheduling and unit commitment of thermal generators, hydro plant and energy storage plant and more competitive market trading as wind power ramps up and down on the grid. This paper presents an in-depth review of the current methods and advances in wind power forecasting and prediction. Firstly, numerical wind prediction methods from global to local scales, ensemble forecasting, upscaling and downscaling processes are discussed. Next the statistical and machine learning approach methods are detailed. Then the techniques used for benchmarking and uncertainty analysis of forecasts are overviewed, and the performance of various approaches over different forecast time horizons is examined. Finally, current research activities, challenges and potential future developments are appraised. (C) 2011 Elsevier Ltd. All rights reserved.

Does first aid have a place in the medical curriculum? A survey of medical students

Introduction: When a medical emergency occurs in the prehospital environment, there is an expectation from the general public for medical students to offer assistance with a similar level of competence as qualified doctors. However, the question is raised; do medical students have sufficient training in first aid skills to fulfil the role expected of them?

Prior to the publication of the latest version of Tomorrow’s Doctors by the UK General Medical Council, a student selected component (SSC) in first aid was delivered at the medical school in Queen’s University Belfast (QUB), Northern Ireland. The overwhelming popularity of this SSC prompted a desire to investigate and understand students’ experiences of first aid.

Aim: To identify first and second year medical students’ knowledge of, and attitudes towards, first aid and their expectations of the medical curriculum.

Methods: A questionnaire was delivered using TurningPoint Audience Response System® during the second semester of the 2008 - 2009 academic year to all first and second year medical students at QUB.

Results: Less than half of the students felt that they had a good level of first aid knowledge, a third would feel confident helping in an emergency and only 10% would be confident leading an emergency situation. The vast majority of students believed first aid is beneficial, that the general public expect medical students to have the knowledge to handle an emergency situation, and that a full first aid course should be included in the core medical curriculum at an early stage. They did not believe it should be a pre-requisite for medical school.

Conclusion: Only a small proportion believed their first aid knowledge adequate. An overwhelming proportion believed that first aid training is beneficial and that the public expect competency in managing emergencies. This study clearly demonstrates students’ need and desire for first aid training in the core medical curriculum at an early stage and to the highest training level possible.

Testate amoebae as indicators of hydroseral change: an 8,500 year record from Mer Bleue Bog, eastern Ontario, Canada.

Testate amoebae have been used widely as a proxy of hydrological change in ombrotrophic peatlands, although their response to abiotic controls in other types of mire and fenland palaeo-environments is less well understood. This paper examines the response of testate amoebae to hydroseral and other environmental changes at Mer Bleue Bog, Ontario, Canada, a large ombrotrophic peatland, which evolved from a brackish-water embayment in the early Holocene. Sediments, plant macrofossils and diatoms examined from a 5.99 m core collected from the dome of the bog record six stages of development: i) a quiet, brackish-water riverine phase (prior to ca. 8500 cal BP); ii) a shallow lake (ca. 8500–8200 cal BP); iii) fen (8200–7600 cal BP); iv) transitional mire (7600–6900 cal BP); v) pioneer raised mire (6900–4450 cal BP); and vi) ombrotrophic bog (4450 cal BP-present).

Testate amoebae, notably small (<25 µm diameter) specimens of Centropyxis aculeata type, first appear in low abundances in sediments ascribed to the lacustrine phase. Diatoms from the same horizons record a shallowing in water depth, a decline in salinity and the development of emergent macrophytic vegetation, which may have provided favourable conditions for testate amoeba colonization. The testate amoeba communities of the inferred fen phase are more diverse and include centropyxids, cyclopyxids, Arcellidae and Hyalospheniidae, although the assemblages show some differences to those recently reported in modern European fen environments. The Fen–Bog Transition (FBT) is also dominated by C. aculeata type. The change in testate amoeba communities around this key transition is apparent in the results of Detrended Correspondence Analysis (DCA), and appears to reflect a latent nutrient gradient and a secondary moisture gradient. DCA analyses of plant macrofossil remains around the FBT show a similar trend, although the sensitivity of the two proxies to the inferred environmental changes differs. Comparisons with other regional mid-Holocene peatland records confirm the important influence of reduced effective precipitation on the testate amoeba communities during the initiation and development of Sphagnum-dominated, raised bog communities.

The Diffusion of Risks in Public Private Partnership Contracts

Purpose The UK government argues that the benefits of public private partnership (PPP) in delivering public infrastructure stem from: transferring risks to the private sector within a structure in which financiers put their own capital at risk; and, the performance based payment mechanism, reinforced by the due diligence requirements imposed by the lenders financing the projects (HM Treasury, 2010). Prior studies of risk in PPPs have investigated ‘what’ risks are allocated and to ‘whom’, that is to the public or the private sector. The purpose of this study is to examine ‘how’ and ‘why’ PPP risks are diffused by their financiers. Design/methodology/approach This study focuses on the financial structure of PPPs and on their financiers. Empirical evidence comes from interviews conducted with equity and debt financiers. Findings The findings show that the financial structure of the deals generates risk aversion in both debt and equity financiers and that the need to attract affordable finance leads to risk diffusion through a network of companies using various means that include contractual mitigation through insurance, performance support guarantees, interest rate swaps and inflation hedges. Because of the complexity this process generates, both procurers and suppliers need expensive expert advice. The risk aversion and diffusion and the consequent need for advice add cost to the projects impacting on the government’s economic argument for risk transfer. Limitations and implications The empirical work covers the private finance initiative (PFI) type of PPP arrangements and therefore the risk diffusion mechanisms may not be generalisable to other forms of PPP, especially those that do not involve the use of high leverage or private finance. Moreover, the scope of this research is limited to exploring the diffusion of risk in the private sector. Further research is needed on how risk is diffused in other settings and on the value for money implication of risk diffusion in PPP contracts. Originality/value The expectation inherent in PPP is that the private sector will better manage those risks allocated to it and because private capital is at risk, financiers will perform due diligence with the ultimate outcome that only viable projects will proceed. This paper presents empirical evidence that raises questions about these expectations. Key words: public private partnership, risk management, diffusion, private finance initiative, financiers

Holocene tephras highlight complexity of volcanic signals in Greenland ice cores

Acidity peaks in Greenland ice cores have been used as critical reference horizons for synchronizing ice core records, aiding the construction of a single Greenland Ice Core Chronology (GICC05) for the Holocene. Guided by GICC05, we examined sub-sections of three Greenland cores in the search for tephra from specific eruptions that might facilitate the linkage of ice core records, the dating of prehistoric tephras and the understanding of the eruptions. Here we report the identification of 14 horizons with tephra particles, including 11 that have not previously been reported from the North Atlantic region and that have the potential to be valuable isochrons. The positions of tephras whose major element data are consistent with ash from the Katmai AD 1912 and Öraefajökull AD 1362 eruptions confirm the annually resolved ice core chronology for the last 700 years. We provide a more refined date for the so-called “AD860B” tephra, a widespread isochron found across NW Europe, and present new evidence relating to the 17th century BC Thera/Aniakchak debate that shows N. American eruptions likely contributed to the acid signals at this time. Our results emphasize the variable spatial and temporal distributions of volcanic products in Greenland ice that call for a more cautious approach in the attribution of acid signals to specific eruptive events.

The influence of evidence-based medicine training on decision-making in relation to over-the-counter medicines: a qualitative study

Objectives
To explore the role of evidence of effectiveness when making decisions about over-the-counter (OTC) medication and to ascertain whether evidence-based medicine training raised awareness in decision-making. Additionally, this work aimed to complement the findings of a previous study because all participants in this current study had received training in evidence-based medicine (unlike the previous participants).

Methods
Following ethical approval and an e-mailed invitation, face-to-face, semi-structured interviews were conducted with newly registered pharmacists (who had received training in evidence-based medicine as part of their MPharm degree) to discuss the role of evidence of effectiveness with OTC medicines. Interviews were recorded and transcribed verbatim. Following transcription, all data were entered into the NVivo software package (version 8). Data were coded and analysed using a constant comparison approach.

Key findings
Twenty-five pharmacists (7 males and 18 females; registered for less than 4 months) were recruited and all participated in the study. Their primary focus with OTC medicines was safety; sales of products (including those that lack evidence of effectiveness) were justified provided they did no harm. Meeting patient expectation was also an important consideration and often superseded evidence. Despite knowledge of the concept, and an awareness of ethical requirements, an evidence-based approach was not routinely implemented by these pharmacists. Pharmacists did not routinely utilize evidence-based resources when making decisions about OTC medicines and some felt uncomfortable discussing the evidence-base for OTC products with patients.

Conclusions
The evidence-based medicine training that these pharmacists received appeared to have limited influence on OTC decision-making. More work could be conducted to ensure that an evidence-based approach is routinely implemented in practice

Material Deprivation, Economic Stress, and Reference Groups in Europe: An Analysis of EU-SILC 2009

In this article, we take advantage of the recent availability of data from the special module on material deprivation in the 2009 European Union Statistics on Income and Living Conditions to develop a more comprehensive understanding of the relationship between material deprivation and economic stress, the mediating and moderating roles played by cross-national differences in levels of income and income inequality, and the implications for competing perspectives on the nature of reference groups in Europe. The article establishes the critical role of basic deprivation, relating to inability to enjoy customary standards of living, in influencing economic stress levels. National income levels and inequality had no direct influence on economic stress. However, the impact of basic deprivation was stronger in countries with higher levels of income, indicating the crucial role of national reference groups. An interaction between basic deprivation and income inequality was also observed. However, contrary to the expectation that experiencing basic deprivation in a national context of high income inequality is likely to be particularly stressful, the consequences of such deprivation were most negative in low inequality countries. Experiencing basic deprivation where high income levels and lower inequality would lead to the expectation that such deprivation is eminently avoidable exacerbates its impact. © The Author 2013.

Regularized Online Mixture of Gaussians for Background Subtraction

Mixture of Gaussians (MoG) modelling [13] is a popular approach to background subtraction in video sequences. Although the algorithm shows good empirical performance, it lacks theoretical justification. In this paper, we give a justification for it from an online stochastic expectation maximization (EM) viewpoint and extend it to a general framework of regularized online classification EM for MoG with guaranteed convergence. By choosing a special regularization function, l1 norm, we derived a new set of updating equations for l1 regularized online MoG. It is shown empirically that l1 regularized online MoG converge faster than the original online MoG .

Insurgent Building: Spatial Practices of Resistance in the Bedouin-State Conflict in Southern Israel

In the con?ict between Bedouin representatives and government authorities in the southern Israeli Negev, the term ‘insurgent building’ refers to the construction of buildings erected in the full expectation that they will be demolished by the Israeli police shortly thereafter. This article analyses how insurgent building is employed as a spatial practice by emerging political actors to claim contested Bedouin landownership. Importantly, insurgent building relies on the ability of media and advocacy organizations to mobilize behind the issue. Most of the relevant scholarship takes the interpretative categories advanced by these actors at face value. Following anthropological debates regarding objecti?cation and categorization, I examine the context of a speci?c case of insurgent building. Emerging political actors who employ insurgent building often rely on prede?ned ethnic categories and clear-cut people–state polarities. This case demonstrates the need for a more differentiated understanding of multilayered local dynamics than the one offered by mainstream linear interpretations. At a more abstract level, political actors contribute to the reproduction of the very categories against which they mobilize.

Weathering rinds as mirror images of palaeosols: Examples from the Western Alps with correlation to Antarctica and Mars

Weathering rinds have been used for decades as relative age indicators to differentiate glacial deposits in long Quaternary sequences, but only recently has it been shown that rinds contain long and extensive palaeoenvironmental records that often extend far beyond mere repositories of chemical weathering on both Earth and Mars. When compared with associated palaeosols in deposits of the same age, rinds often carry a zonal weathering record that can be correlated with palaeosol horizon characteristics, with respect to both abiotic and biotic parameters. As demonstrated with examples from the French and Italian Alps, rinds in coarse clastic sediment contain weathering zones that correlate closely with horizon development in associated palaeosols of presumed Late Glacial age. In addition to weathering histories in both rinds and palaeosols, considerable evidence exists to indicate that the black mat impact (12.8 ka) reached the European Alps, a connection with the Younger Dryas readvance supported by both mineral and chemical composition. Preliminary metagenomic microbial analysis using density gradient gel electrophoresis suggests that the eubacterial microbial population found in at least one Ah palaeosol horizon associated with a rind impact site is different from that in other Late Glacial and Younger Dryas surface palaeosol horizons. © 2013 The Geological Society of London.

Current Status of Offshore Wind Power Development in China

In July 2010, the Shanghai Donghai Bridge wind farm, the first commercial offshore wind project was connected to the main grid in China. Three months later, four contracts were handed out to build a total of 1GW wind power capacity in the first round of an offshore concession project by the Chinese central government. At that time, there was a worldwide expectation that Chinese offshore wind power capacity would expand rapidly. However, China only achieved a total offshore wind power installed capacity of 389.2 MW by the end of 2012. This paper studies the recent development of offshore wind power in China by dividing the offshore wind power projects into three categories. This paper presents the difficulties for the Chinese government to achieve its 12th Five Year Plan for offshore wind power. Some policy recommendations to overcome the current difficulties are made in the conclusions.

The lateritic profile of Balkouin, Burkina Faso: geochemistry, mineralogy and genesis

This study reports on the geochemical and mineralogical characterization of a lateritic profile cropping out in the Balkouin area, Central Burkina Faso, aimed at obtaining a better understanding of the processes responsible for the formation of the laterite itself and the constraints to its development. The lateritic profile rests on a Paleoproterozoic basement mostly composed of granodioritic rocks related to the Eburnean magmatic cycle passing upwards to saprolite and consists of four main composite horizons (bottom to top): kaolinite and clay-rich horizons, mottled laterite and iron-rich duricrust. In order to achieve such a goal, a multi-disciplinary analytical approach was adopted, which includes inductively coupled plasma (ICP) atomic emission and mass spectrometries (ICP-AES and ICP-MS respectively), X-ray powder diffraction (XRPD), scanning electron microscopy with energy dispersive spectrometry (SEM-EDS) and micro-Raman spectroscopy.

The geochemical data, and particularly the immobile elements distribution and REE patterns, show that the Balkouin laterite is the product of an in situ lateritization process that involved a strong depletion of the more soluble elements (K, Mg, Ca, Na, Rb, Sr and Ba) and an enrichment in Fe; Si was also removed, particularly in the uppermost horizons. All along the profile the change in composition is coupled with important changes in mineralogy. In particular, the saprolite is characterized by occurrence of abundant albitic plagioclase, quartz and nontronite; kaolinite is apparently absent. The transition to the overlying lateritic profile marks the breakdown of plagioclase and nontronite, thus allowing kaolinite to become one of the major components upwards, together with goethite and quartz. The upper part of the profile is strongly enriched in hematite (+ kaolinite). Ti oxides (at least in part as anatase) and apatite are typical accessory phases, while free aluminum hydroxides are notably absent. Mass change calculations emphasize the extent of the mass loss, which exceeds 50 wt% (and often 70 wt%) for almost all horizons; only Fe was significantly concentrated in the residual system.

The geochemical and mineralogical features suggest that the lateritic profile is the product of a continuous process that gradually developed from the bedrock upwards, in agreement with the Schellmann classic genetic model. The laterite formation must have occurred at low pH (? 4.5) and high Eh (? 0.4) values, i.e., under acidic and oxidizing environments, which allowed strongly selective leaching conditions. The lack of gibbsite and bohemite is in agreement with the compositional data: the occurrence of quartz (± amorphous silica) all along the profile was an inhibiting factor for the formation of free aluminum hydroxides.

Evaluation of the contribution of theatre attendance to medical undergraduate neuroscience teaching - a pilot study.

Introduction: Medical students often attend the neurosurgical theatre during their clinical neurosciences attachment. However, few studies have been performed to objectively assess the value of this theatre-based learning experience. The main aim of this study was to explore student perceptions on the contribution of neurosurgical theatre attendance to clinical neuroscience teaching.

Materials and Methods: Third-year medical students undergoing their 2-week clinical neurosciences rotation at the Royal Hospitals Belfast were invited to participate in this study. A multi-method strategy was employed using a survey questionnaire comprising of closed and open-ended questions followed by semi-structured interviews to gain a greater 'in-depth' analysis of the potential contribution of neurosurgical theatre attendance to neuroscience teaching.

Results: Based on the completed survey responses of 22 students, the overall experience of neurosurgical theatre-based learning was a positive one. 'In-depth' analysis from semi-structured interviews indicated that students felt that some aspects of their neurosurgical theatre attendance could be improved. Better preparation such as reading up on the case in hand and an introduction to simple theatre etiquette to put the student at ease (in particular, for students who had never attended theatre previously), would improve the learning experience. In addition, having an expectation of what students are expected to learn in theatre making it more learning outcomes-based would probably make it feel a more positive experience by the student.

Conclusions: The vast majority of students acknowledged the positive learning outcomes of neurosurgical theatre attendance and felt that it should be made a mandatory component of the curriculum.

Characterizing changes in the excitability of corticospinal projections to proximal muscles of the upper limb

Background: There has been an explosion of interest in methods of exogenous brain stimulation that induce changes in the excitability of human cerebral cortex. The expectation is that these methods may promote recovery of function following brain injury. To assess their effects on motor output, it is typical to assess the state of corticospinal projections from primary motor cortex to muscles of the hand, via electromyographic responses to transcranial magnetic stimulation. If a range of stimulation intensities is employed, the recruitment curves (RCs) obtained can, at least for intrinsic hand muscles, be fitted by a sigmoid function.

Objective/hypothesis: To establish whether sigmoid fits provide a reliable basis upon which to characterize the input–output properties of the corticospinal pathway for muscles proximal to the hand, and to assess as an alternative the area under the (recruitment) curve (AURC).

Methods: A comparison of the reliability of these measures, using RCs obtained for muscles that are frequently the targets of rehabilitation.

Results: The AURC is an extremely reliable measure of the state of corticospinal projections to hand and forearm muscles, which has both face and concurrent validity. Construct validity is demonstrated by detection of widely distributed (across muscles) changes in corticospinal excitability induced by paired associative stimulation (PAS).

Conclusion(s): The parameters derived from sigmoid fits are unlikely to provide an adequate means to assess the effectiveness of therapeutic regimes. The AURC can be employed to characterize corticospinal projections to a range of muscles, and gauge the efficacy of longitudinal interventions in clinical rehabilitation.