bluuebunny/crossref_metadata_2025 huggingface dataset:
Dangerous liaisons
Authors: Melhuish Lynsey
Published: January 2017

This article explores the aspects of employer engagement in higher education (HE). The vocational field of the adventure and outdoor industry provides the context, with associated undergraduate degrees offering contemporary ‘real-world’ provision, underpinned by values of inclusivity and widening participation – an approach that addresses issues high on the government and HE agendas and of which employer engagement is an integral part. The field also reflects the evolution of modern vocational degree programmes and the tensions that persist between ‘traditional’ and ‘non-traditional’ provision alongside changing industry demands. In a constantly changing global, political and social environment, UK universities are under increasing pressure from government to strengthen university–employer cooperation. This article examines key factors that universities, industry and government should consider when advocating real-world learning and the potential of employer engagement, including the powerful influence of the ‘student’ perspective and demands for a high-quality experience and satisfaction in terms of career preparation.
The effectiveness of entrepreneurship training programmes
Authors: Matricano Diego , Formica Piero
Published: January 2017

This special issue of Industry and Higher Education focuses on the increasingly important topic of how the effectiveness of entrepreneurship education can be appropriately measured. Despite extensive research on entrepreneurship education and training programmes, relatively few studies have concentrated on the consequences of such programmes – for example, on assessing their actual impact on the commitment of aspiring entrepreneurs. Against this background, the guest editors present four contributions, each addressing key issues relating to the evaluation and measurement of entrepreneurship education. These contributions, it is hoped, will open new directions for researchers and will provide programme designers and policymakers with valuable strategic information.
US Universities and Technology Transfer
Authors: Rahm Dianne
Published: January 2017

This article attempts to improve our understanding of the university–firm technology transfer process in several ways. First, a model of technology transfer which subdivides this complicated activity into several small and more readily understandable dimensions is developed. Next, questions relevant to each dimension from the perspective of both the university administrator and the university researcher are asked. Answers to the questions explored are drawn from results of a survey of administrators and researchers associated with the top 100 US research universities.
Work Placement in Japan
Authors: Huggett Susan A.
Published: January 2017

International work placement programmes are an important part of preparing the workforce for the global economy. However, cultural, language and other barriers make establishing relationships between companies and universities difficult and time consuming. The Canadian Co-op Japan Program organizes work placements for Canadian science and engineering students in Japan and its experience is presented as a model for similar international programmes.
More dangerous than dyads: how a third party enables rationalist explanations for war
Authors: Gallop Max
Published: January 2017

For the bargaining model of war, in the absence of incomplete information and commitment problems, war is irrational. But this finding rests on a simple and rarely discussed assumption, that bargaining is between exactly two participants. When we relax this assumption, in a three-player bargaining game, war is an equilibrium. Thus, a key finding of the bargaining model, that there is always an agreement that all states prefer war, is an artifact of dyadic analysis. By removing this limitation, we can find new factors that affect the risk of war: the number of actors, divergence in state preferences, alliance dynamics, and the issue being bargained over.
Outcomes and outputs: Long-term effects of Temporary Assistance for Needy Families on caseload enrollment and poverty
Authors: Bunch Jaclyn , Liebertz Scott , Milita Kerri
Published: January 2017

The Welfare Reform Legislation of 1996 is often cited as one of President Clinton’s most notable achievements, as this law was followed by sizable reductions in states’ welfare loads. Did this policy devolution lead to lower state poverty—as was suggested by reform advocates? We re-examine the effects of the new welfare regime on state-level poverty and welfare enrollment between 1996 and 2012. This is important to complement existing studies of individual-level experience with the welfare system. Our analysis confirms that the federal-to-state welfare transition eased the states’ caseload burden and poverty rate. We also find evidence that the relationship between welfare restrictiveness and caseload burden was strongest in the period before the recession, and with the inclusion of post-recession years, higher level restrictiveness may have little to no effect on reducing caseload. While state decisions to increase welfare restrictiveness did reduce poverty, our results show no added benefit to those with the highest levels of welfare restrictions. These findings reinforce the need to match policy goals to social outcomes, rather than relying on output measures such as caseload reduction.
Indeno[1,2-b]fluorene-based novel donor–acceptor conjugated copolymers
Authors: Sun Ying , Ding Xiaojing , Zhang Xueqin , Huang Qizan , Lin Baoping , Yang Hong , Guo Lingxiang
Published: January 2017

A series of conjugated copolymers based on indeno[1,2-b]fluorene as donor unit with different acceptor units have been synthesized to explore the influences of molecular backbone planarization and acceptor electronegativity on charge transport and photovoltaic properties. Polymer incorporating 2,3-diphenylquinoxaline acceptor moiety shows poor light-harvesting capacity and inferior photovoltaic efficiency of 0.5% due to twisted geometry. By introducing the stronger acceptor thiadiazolo[3,4-c]pyridine in polymer, intramolecular charge transfer is enhanced, giving rise to improved absorption property and photovoltaic efficiency of 1.39%. However, the polymer backbone is still twisted. When thiophene-flanked diketopyrrolopyrrole (DPP) is incorporated as electron acceptor, the polymer exhibits a more planar molecular geometry, yielding a broader and red-shifted absorption spectrum as well as a significantly improved hole mobility of 1.46E-2 cm2 V−1 s−1. However, the photovoltaic device efficiency is only enhanced to be 1.69%. The low-lying lowest unoccupied molecular orbital of −3.95 eV as a result of the strong electron deficiency of the DPP unit may lead to the inefficient charge dissociation and increase the charge recombination, which may give rise to the limit photovoltaic performance.
Using the direct cutting paths approach on aluminum alloy cone frustum part for evaluating a five-axis machine tool with Taguchi method
Authors: Chang Han-Jui , Chen Shang-Liang , Lee Po-Yi
Published: January 2017

It is difficult to compare five-axis machine tools complex analysis against independent motion of multi-type machines; more specifically, there has been no breakthrough involving the interaction effect factors from cutting analysis. Therefore, the defining and quantifying of data are important in assessing the overall performance of five-axis machine tools, and allow for the evaluation of each subsequent interaction motion analysis. Among various cutting test models, the machining of a cone frustum as specified in National Aerospace Standard 979 and International Standard Organization 10791-7 is widely accepted as a performance test standard for five-axis machining centers. Although it gives a demonstration of the machine’s machining performance, it is generally difficult to identify the overall effects of kinematic interaction within the profile of the finished workpiece. This is new approach to a previously defined 10 direct cutting paths method to evaluate the performance of each cone frustum motion, and it is not limited to only evaluating single direction or displacement on a five-axis machine tool. Among the 10 cutting paths, four of them are real five-axis cutting and the remaining paths are non-real five-axis cutting. This allowed the test of four to five mixed external forces at the same time, which the instrument is not able to measure. This article further proposes to calculate the factorial effect of interaction, based on the Taguchi method signal-to-noise ratio, mechanical advantage, and Variables separable model, which allows for the comparison of the performance of different five-axis machine tool types.
Investigation on an industrial-feasible approach for measurement and assessment of large-sized micro-structured surfaces based on grayscale matching
Authors: Huang Honghui , Ding Hui , Cheng Kai , Zhao Liang , Ma Shuwen
Published: January 2017

Multi-scale micro-structured functional surfaces can enhance the interfacial effect on a component by the micro-topological structure, likely through realizing or enhancing its lubrication, drag reduction, noise reducing, sealing, and other specific surface functions. However, the realization of these functions requires high-precision machining quality and the occurrence of any defects on the structured surfaces will possibly influence actual performances of the component. The distribution density, morphology, geometry, configuration feature, and position of those microstructures play a decisive role in affecting the functional performance of the component. It imposes a challenge for rapid and accurate measurement of micro-structured surface particularly at a reasonable large size in industrial-scale production. This article presents an innovative industrial-feasible measurement method for micro-structured surfaces using normalized grayscale matching combined with pyramid search strategy, discriminating-step matching strategy, and sensitive area analysis. The method renders the high matching accuracy and rapid processing capability, which also provides the technical solution for industrial-scale micro-manufacturing of large-sized micro-structured surfaces. Well-designed experimental trials are carried out to further evaluate and validate the measurement accuracy and efficiency.
Three-dimensional numerical modeling, simulation and experimental validation of milling of a thin-wall component
Authors: Bolar Gururaj , Joshi Shrikrishna N
Published: January 2017

Study on mechanics of milling of thin-wall components using a helical end mill is important in view of its complex nature and prominent applications in aerospace, automobile and electronics areas. This article presents a realistic three-dimensional, thermo-structural, finite-element-based mathematical model for thin-wall milling of aerospace grade aluminum alloy. Lagrangian formulation with explicit solution scheme was employed to simulate the interaction between helical milling cutter and the workpiece. Behavior of the material at high strain, strain rate and temperature was defined by Johnson–Cook material constitutive model. Johnson–Cook damage law and friction law were used to account for chip separation and contact interaction. Experimental work was carried out to validate the results predicted by the mathematical model. The developed model predicted the forces in radial, feed and axial directions with errors of 14%, 26% and 33%, respectively. The prediction errors for deflections at top, middle and bottom portions of thin wall were within 11%–39%. The simulated chip dimensions were in good agreement with experimental results while the computed cutting temperature varied by 17% with respect to the experimental value. Overall, it was found that the developed model predicts the process responses with fair and acceptable prediction accuracy. Using the developed model, a study on the effect of process parameters on the performance parameters, namely cutting and thrust forces, stress distribution, cutting temperature, part deflection and chip morphology was carried out, which is not possible using a two-dimensional orthogonal or oblique cutting model. It was found that the developed three-dimensional mathematical model provided very useful insights into the complex physical interaction of helical cutting tool and workpiece during thin-wall milling of aerospace alloys.
Experimental and numerical investigations on springback in V-bending of tailor-welded blanks of interstitial free steel
Authors: Gautam Vijay , Kumar D Ravi
Published: January 2017

Tailor-welded blanks of interstitial free steel are commonly used in complex automotive skin panels. The presence of weld zone, difference in thickness and high anisotropic behaviour affect forming behaviour of tailor-welded blanks significantly. Therefore, incorporation of anisotropy of the sheets and properties of the weld zone in finite element simulations is very important for accurate prediction of springback in bending of tailor-welded blanks. In this study, experimental and finite element simulations of V-bending were carried out on tailor-welded blanks of three thickness combinations, prepared by Nd-YAG laser welding of interstitial free steel sheets of thicknesses 0.8, 1.2 and 1.5 mm. The orientation of the weld line in longitudinally welded blanks was kept at 0°, 45° and 90° with respect to the rolling direction to study the effects of anisotropy on springback in V-bending. The tensile properties of the weld zone in different thickness combinations were determined and incorporated in finite element simulations for prediction of springback. It was observed that springback results were mainly governed by the springback behaviour of the thicker sheet in a particular thickness combination. Weld zone properties affect the springback of tailor-welded blanks more significantly than the anisotropy of the sheets. Accuracy of predicted values of springback in simulations increased when the properties of the weld zone were incorporated in the material model.
Singularity analysis of two-legged planar parallel robots with three degrees of freedom
Authors: Özdemir Mustafa
Published: January 2017

Planar two-legged parallel robots with three degrees of freedom have been suggested in the literature as a solution to reduce the leg interference problem of their conventional three-legged counterparts, and since then have attracted considerable attention. This paper presents a singularity analysis of these robots. Three alternatives, namely the robots with 2-RRR, 2-RPR, and 2-PRR structures are considered. Type I, II, and III singularity conditions are obtained taking into account all possible actuation schemes. Several singularity-free actuation schemes are enumerated and discussed. The performed analysis also shows that adjustable designs are possible for manipulators with 2-PRR structures to have singularity-free operation. The proposed design concept and its effectiveness are illustrated through numerical examples.
Topology optimization of structures with coupled finite element – Element-free Galerkin method
Authors: Zhang Yaqing , Ge Wenjie , Tong Xinxing , Ye Min
Published: January 2017

A topology optimization, based on a coupling method of finite element and meshless method, is proposed for continuum structure. A reasonable arrangement of the meshless domain can guarantee the accuracy of the meshless methods and meanwhile keep the computational efficiency of the finite element method. Besides, as the coupling method is adopted, the displacement boundary conditions are applied to finite elements nodes by standard finite element method. A dual-level density approximant is carried out to approximate and interpolate a unified and continuous density field. An unstable nodes phenomenon is observed in the interface domain, leading to nonconvergence of the equilibrium iterations. A smooth blending function and an energy convergence criterion are used to circumvent the convergent difficulty. Three benchmark problems of topology optimization are given to demonstrate the effectiveness of the proposed approach. Neither “islanding” phenomenon nor other common numerical instabilities of the SIMP method occur in this approach.
Experimental study on tissue phantoms to understand the effect of injury and suturing on human skin mechanical properties
Authors: Chanda Arnab , Unnikrishnan Vinu , Flynn Zachary , Lackey Kim
Published: January 2017

Skin injuries are the most common type of injuries occurring in day-to-day life. A skin injury usually manifests itself in the form of a wound or a cut. While a shallow wound may heal by itself within a short time, deep wounds require surgical interventions such as suturing for timely healing. To date, suturing practices are based on a surgeon’s experience and may vary widely from one situation to another. Understanding the mechanics of wound closure and suturing of the skin is crucial to improve clinical suturing practices and also to plan automated robotic surgeries. In the literature, phenomenological two-dimensional computational skin models have been developed to study the mechanics of wound closure. Additionally, the effect of skin pre-stress (due to the natural tension of the skin) on wound closure mechanics has been studied. However, in most of these analyses, idealistic two-dimensional skin geometries, materials and loads have been assumed, which are far from reality, and would clearly generate inaccurate quantitative results. In this work, for the first time, a biofidelic human skin tissue phantom was developed using a two-part silicone material. A wound was created on the phantom material and sutures were placed to close the wound. Uniaxial mechanical tests were carried out on the phantom specimens to study the effect of varying wound size, quantity, suture and pre-stress on the mechanical behavior of human skin. Also, the average mechanical behavior of the human skin surrogate was characterized using hyperelastic material models, in the presence of a wound and sutures. To date, such a robust experimental study on the effect of injury and sutures on human skin mechanics has not been attempted. The results of this novel investigation will provide important guidelines for surgical planning and validation of results from computational models in the future.
Toward the definition of a new worst-case paradigm for the preclinical evaluation of posterior spine stabilization devices
Authors: La Barbera Luigi , Villa Tomaso
Published: January 2017

Mechanical reliability tests on posterior spine stabilization devices are based on standard F1717 by the American Society for Testing and Materials, which describes how to assemble the implant with vertebrae-like test blocks in a corpectomy model. A recent study proposed to revise the standard to describe the anatomical worst-case scenario, instead of the average one currently implemented, and introduce the unsupported screw length as a mechanical parameter. This article investigates the implications of such revisions on the endurance properties of an implant already on the market. Experimental fatigue tests demonstrate that the revision of F1717 standard leads to a reduction of 3.2 million cycles in the fatigue strength of the tested implant: this amount is comparable to the run-out number of cycles (5 million cycles) currently recommended. The numerical analysis, validated with static tests and strain gauges, supports the experimental findings and demonstrates that the stress on the implant may increase upon revision up to a 50% on the screw (most recurrent failure mode), with the unsupported screw length contributing alone up to 40%. The revision of ASTM F1717 standard would guarantee higher safety for the implant to test, potentially covering for a wider population of patients.
Pullout performance comparison of novel expandable pedicle screw with expandable poly-ether-ether-ketone shells and cement-augmented pedicle screws
Authors: Aycan Mehmet Fatih , Tolunay Tolga , Demir Teyfik , Yaman Mesut Emre , Usta Yusuf
Published: January 2017

Aim of this study is to assess the pullout performance of various pedicle screws in different test materials. Polyurethane foams (Grade 10 and Grade 40) produced in laboratory and bovine vertebrae were instrumented with normal, cannulated (cemented), novel expandable and normal (cemented) pedicle screws. Test samples were prepared according to the ASTM F543 standard testing protocols and surgical guidelines. To examine the screw placement and cement distribution, anteriosuperior and oblique radiographs were taken from each sample after insertion process was completed. Pullout tests were performed in an Instron 3369 testing device. Load versus displacement graphs were recorded and the ultimate pullout force was defined as the maximum load (pullout strength) sustained before failure of screw. Student’s t-test was performed on each group whether the differences between pullout strength of pedicle screws were significant or not. While normal pedicle screws have the lowest pullout strength in all test materials, normal pedicle screws cemented with polymethylmethacrylate exhibit significantly higher pullout performance than others. For all test materials, there is a significant improvement in pullout strength of normal screws by augmentation. While novel expandable pedicle screws with expandable poly-ether-ether-ketone shells exhibited lower pullout performance than normal screws cemented with polymethylmethacrylate, their pullout performances in all groups were higher than the ones of normal and cannulated pedicle screws. For all test materials, although cannulated pedicle screws exhibit higher pullout strength than normal pedicle screws, there are no significant differences between the two groups. The novel expandable pedicle screws with expandable poly-ether-ether-ketone shells may be used instead of normal and cannulated pedicle screws cemented with polymethylmethacrylate due to their good performances.
Stage IV advanced diffuse large B-cell lymphoma in human immunodeficiency virus infection with achieving cure by using highly active antiretroviral therapy alone: a case report
Authors: Lim Do Hyoung , Rhee Ji-Young , Park Keon Woo
Published: January 2017

After the introduction of highly active antiretroviral therapy (HAART), there has been a decrease in the incidence of lymphoma among the HIV-infected population and also significantly improved survival rates. We describe a remarkable case of an HIV-infected patient with advanced stage IV diffuse large B-cell lymphoma (DLBCL), completely regressed with the use of HAART alone. He remained disease-free for 6 years and he achieved cure without chemotherapy. Although several cases of low-grade lymphoma with complete regression were reported, we could not find any case of stage IV high-grade malignant lymphoma with HAART alone in complete remission for over 5 years from our review of the literature. This unique case shows the importance of HAART in improving survival and achieving cure in HIV–high-grade malignant lymphoma.
Numerical analysis of a Pelton bucket free surface sheet flow and dynamic performance affected by operating head
Authors: Zeng Chongji , Xiao Yexiang , Wang Zhengwei , Zhang Jin , Luo Yongyao
Published: January 2017

The present paper aims to find out the influence of operating head on the rotating bucket free surface sheet flow and hydrodynamics performance for a Pelton turbine. Three-dimensional unsteady air-water two-phase flow simulations in the rotating buckets were performed by adopting the shear stress transport curvature correction turbulence model and homogenous model. The sensitivities of the unsteady simulation results to moving mesh resolution and computational fluid dynamics solver time-step have been evaluated to discuss the effect of Courant–Friedrichs–Lewy conditions on the two-phase flow simulation. The accuracy of the numerical predicted flow pattern and the hydrodynamic performance results are reasonable when compared with the experimental data. The simulation results indicate that the remaining kinetic energy carried by the outflow under the nondesigned water head is the main reason for the efficiency loss in the Pelton turbine. Under low water head conditions, jet distortion caused by the Coanda effect and flow interference will lead to more severe efficiency deterioration.
Beyond the day-ahead market – effects of revenue maximisation of the marketing of renewables on electricity markets
Authors: Winkler Jenny , Emmerich Rouven , Ragwitz Mario , Pfluger Benjamin , Senft Christian
Published: January 2017

The proportion of renewable energy has rapidly increased in many countries during the last few years. Due to the specific characteristics of variable renewables, this development influences the price on electricity markets as well as flexibility requirements in the electricity system. New developments regarding market liberalisation and support schemes for renewables encourage the active participation of renewables in the electricity market. This paper analyses the effects of such a participation of renewables in different electricity market segments. In particular, we investigate how the active marketing of renewables on the day-ahead, intra-day, balancing and futures markets dampen their effects on markets and systems. Using German data for 2013, we determine the effect of direct marketing on average market price levels and price volatility, the possible contribution of renewables to balancing, the profitability of flexible generation from biomass, and the additional revenues that renewables can generate from participating in different markets. Price effects of shifting renewables between markets, and limits in intra-day market liquidity are included in the assessment.
Key practices of equality within long parental leaves
Authors: Schadler Cornelia , Rieder Irene , Schmidt Eva-Maria , Zartler Ulrike , Richter Rudolf
Published: January 2017

The birth of a child often reinforces an unequal division of employment and care work among heterosexual couples. Parental leave programmes that foster long leaves tend to increase this inequality within couples. However, by investigating a particularly long parental leave system, we show that specific practices enable parents to share care work equally. Our ethnographic study includes interviews with heterosexual couples, observations in prenatal classes and information material available to parents. Specific sets of practices – managing economic security, negotiating employment, sharing information with peers and feeding practices – involved parents who shared care work equally and parents who divided care work unequally. Contingent on specific situated practices, the arrangement of care work shifted in an equal or unequal direction. Even within long parental leaves, equality between parents was facilitated when economic security was provided through means other than income, when work hours were flexible, mothers had a close relationship to work, information on sharing equally was available and children were bottle-fed. Consequently, an equal share of care work is not the effect of solely structural, individual, cultural or normative matters, but of their entanglement in practices.
Human impact on small-mammal diversity during the middle- to late-Holocene in Iberia: The case of El Mirador cave (Sierra de Atapuerca, Burgos, Spain)
Authors: Bañuls-Cardona Sandra , Martín Rodríguez Patricia , López-García Juan Manuel , Morales Juan Ignacio , Cuenca-Bescós Gloria , Vergès Josep María
Published: January 2017

The human impact on the environment in the Holocene has usually been characterized on the basis of palaeobotanical records, but attempts to distinguish the anthropogenic impact from natural events in landscape evolution have been the subject of much debate in recent years. The aim of this paper is to analyse small-mammal diversity and the presence of synanthropic species, whose small size makes them more sensitive to any changes in their environment that may occur. This study has allowed us to characterize palaeoclimatic and palaeoenvironmental changes, recording small changes whether resulting from a human influence or otherwise. Our object of study is El Mirador cave, which has a sequence with a well-documented human occupation extending from 7200 to 3000 cal. BP. The study has led us to differentiate two phases. In one phase, we can see small changes in diversity related to climatic oscillations from ca. 7200 to 6800 cal. BP, while in the second phase, lasting from ca. 6800 to 3000 cal. BP, the changes in diversity and in the assemblage of synanthropic species are associated with human economic strategies. Moreover, we distinguish which kinds of economic activity (crop and livestock farming) have influenced these changes, because some small-mammal species are influenced, positively or negatively, by environmental changes based on crop farming and animal husbandry. All this information is contrasted with other archaeological proxies, such as the large-mammal and palaeobotanical assemblages from El Mirador cave. Furthermore, this integrative analysis has made it possible to identify the existence of altered environments more generally throughout the Iberian Peninsula from ca. 6000 cal. BP. It additionally confirms the theory of low human occupation intensity in the northern Meseta and in high mountainous areas during the early Neolithic.
Modern pollen rain as a background for palaeoenvironmental studies in the Serra dos Carajás, southeastern Amazonia
Authors: Guimarães José Tasso Felix , Rodrigues Tarcísio Magevski , Reis Luiza Santos , de Figueiredo Mariana Maha Jana Costa , da Silva Delmo Fonseca , Alves Ronnie , Giannini Tereza Cristina , Carreira Léa Maria Medeiros , Dias Anna Christina Rio , da Silva Edilson Freitas , Sahoo Prafulla Kumar , Sousa da Silva Marcio , Souza-Filho Pedro Walfir Martins
Published: January 2017

Several alternative interpretations of the pollen records of lake sediments in the Amazonia may arise due to a lack of understanding of the modern environments, mainly related to pollen–vegetation relationship. Therefore, in this work, we studied the modern pollen rain in sediments of the Amendoim Lake, plateaus of the Serra Sul dos Carajás, southeastern Amazonia. This study indicates the predominance of pollen grains from forest formation (ombrophilous forests and capão florestal) over montane savanna in the lake sediments, despite the fact that montane savanna occupies ~90% of the drainage basin. Additionally, these sediments reflect stronger signal of pollen from ombrophilous forests that occur in the slopes of the plateau. Important components of montane savanna such as Vellozia and Cereus were not observed in the modern pollen rain, which may be related to their shorter flowering periods restricted to the beginning of wetter conditions. The absence of Sacoglottis, Trichilia, Clusia, Emmotum, Guapira and Simarouba in the pollen rain is likely associated with different pollination strategy. The occurrence of windblown pollen of Alchornea, Pseudolmedia, Ilex and Cecropia, which are found from low to highlands of the Carajás region, reinforces a regional vegetation signal in sediments. Several plants from the studied site have been improperly described, according to taxonomy and ecology. For example, the current occurrence of Ilex and Styrax in the study site clearly suggests that they cannot be used as indicators of colder palaeoclimate conditions, as previously described. In addition, Poaceae can be found in drier to wetter substrate conditions, and abundance of their pollen grains in lakes can significantly vary according to relief morphology and cannot indicate palaeovegetation openness. Therefore, this work is a good background for further palaeobotany studies for this region.
Organic geochemical and palynological evidence for Holocene natural and anthropogenic environmental change at Lake Dojran (Macedonia/Greece)
Authors: Thienemann Matthias , Masi Alessia , Kusch Stephanie , Sadori Laura , John Stephan , Francke Alexander , Wagner Bernd , Rethemeyer Janet
Published: January 2017

In this study, we present lipid biomarker and palynological data for a sediment core from Lake Dojran (Macedonia/Greece), which covers the entire Holocene period. We analyzed vascular plant-derived n-alkanes, combustion-derived polycyclic aromatic hydrocarbons (PAHs), fecal steroids, and bacterial and archaeal glycerol dialkyl glycerol tetraether (GDGT) lipids in concert with microcharcoal and pollen assemblages to reconstruct climatic, environmental, and human impact in the Dojran catchment and the greater Dojran area. Overall, our results suggest a relationship between anthropogenic activity and environmental/climatic change since increased human impact corresponds to phases of higher humidity and high lake levels at Lake Dojran. During the early Holocene, the record reveals increasing temperatures and humidity and concurrent increasing vegetation cover and runoff/soil erosion, respectively. Following a thermal maximum during the middle early Holocene, temperatures decrease gradually until present. The middle-Holocene at Lake Dojran is characterized by relatively stable environmental conditions followed by greater climatic instability and strong anthropogenic overprint during the late-Holocene. The fecal stanol record reveals phases of increased human impact during the early Bronze Age, the late Bonze/early Iron Age, and the Middle Ages. A phase of low stanol and PAH concentrations from the late Iron Age until the early Middle Ages is either related to ecosystem changes and/or changes in settlement pattern since concurrent pollen data indicate intensified land use. Human impact re-intensified during the Middle Ages with some variability probably related to climatic variations of the ‘Medieval Warm Period’ and the ‘Little Ice Age’.
Lacustrine record of last millennia eruptions in Northern Chilean Patagonia (45–47°S)
Authors: Fagel Nathalie , Alvarez Denisse , Namur Olivier , Devidal Jean-Luc , Nuttin Laurence , Schmidt Sabine , Jana Patricia , Torrejon Fernando , Bertrand Sebastien , Araneda Alberto , Urrutia Roberto
Published: January 2017

Due to its tectonic setting, the Andean Southern Volcanism Zone (SSVZ) is characterized by frequent volcanic activity. Chilean Patagonia lake sediments represent powerful archives of historical and past eruptions since the deglaciation. The lacustrine tephra record is investigated in 10 Holocene sedimentary cores collected in five lakes located along a 45–47° transect through Northern Chilean Patagonia. All the tephras identified by visual observation and strong magnetic susceptibility signal have been characterized for the major chemical composition of their glass shards by microprobe analyses, bulk mineralogical content by x-ray diffraction analyses and grain-size distribution by laser diffraction. Special care has been given to the chronostratigraphical framework in order to determine the age interval for each tephra layer and further to correlate the lacustrine records. The sedimentary age models are based on 210Pb data and calibrated radiocarbon dates measured on macroremains or reservoir effect-corrected bulk sediment. To present a more complete tephrochronological record, 28 microtephras have been confirmed by their mineralogical signature. Our lacustrine tephra record is compared with the Holocene eruptions registered in both surface deposits and continental, lacustrine and peat bog, environments. The different lacustrine eruption records are discussed according to their origin, age and location (distance from volcanoes, wind direction and dispersion of eruption produced). Our data confirm that Chilean Ande SSVZ tephras are mainly derived from historical and past Hudson eruptions. However, the peculiar low-K2O signature of the glass shards observed in one tephra layer from the Northernmost lake, Lake Thompson, confirms an influence from some other SSVZ volcanoes with low-abundance magma type, such as Maca and Cay. Our tephrochronological data compliment the database for volcanic activity in Chile bringing new information essential for the running discussion on the temporal distribution of eruptions over the Holocene.
Rates and processes of aeolian soil erosion in West Greenland
Authors: Heindel Ruth C , Culler Lauren E , Virginia Ross A
Published: January 2017

In arid landscapes across the globe, aeolian processes are key drivers of landscape change, but arid Arctic regions are often overlooked. In the Kangerlussuaq region of West Greenland, strong katabatic winds have removed discrete patches of soil and vegetation, exposing unproductive glacial till and bedrock. Although lake-sediment records suggest that landscape destabilization began approximately 1000 years ago, the upland soil erosion has never been directly dated. We use a novel application of lichenometry to estimate the rates and timing of soil erosion. We show that the formation of deflation patches occurred approximately 800–230 years ago, in general agreement with lake-sediment records. In West Greenland, the ‘Little Ice Age’ (AD 1350–1880) was characterized by a cold and arid climate, conditions that increased susceptibility to erosion. On average, deflation patches are expanding at a rate of 2.5 cm yr−1, and variation in the rate of patch expansion cannot be explained by proximity to the Greenland Ice Sheet (GrIS), slope, aspect, elevation, or patch size. An erosional threshold exists in this aeolian system, with climate conditions necessary for patch formation likely harsher than those necessary for continued patch expansion, a result that has implications for land management in arid regions. Currently, deflation patches are expanding throughout the study region and are forming in areas close to the GrIS, but future deflation rates are dependent on projected climate and potential land-use changes. Our results stress the importance of aeolian processes in arid polar landscapes such as Kangerlussuaq, and demonstrate the use of aeolian landforms in paleoclimate reconstructions and predicting future landscape change.
Is it possible to determine formation processes of organic deposits through polysaccharides? Pilot study from the prehistoric site in Brandýs nad Labem, Czech Republic
Authors: Rejšek Klement , Turek Jan , Vranová Valerie , Hadacz Roman , Lisá Lenka
Published: January 2017

This paper deals with a possible interpretation value of biochemical methods in comparison with the classic tools of geoarchaeology for the evaluation of formation processes. Organic rich layers from the archaeological site Brandýs nad Labem-Vrábí were tested with the aim to determine the origin of several different types of soil organic material by analyzing the content of different sugars. The studied soil body showed signs of cultural layer, redeposited soils, and in situ developed soil. The analysis of different sugars was highlighted: soil samples taken from these layers were analyzed to assess the ratios of mannose + galactose to arabinose + xylose, and of rhamnose + fucose to arabinose + xylose, content of Corg and different nitrates, as well as different rates of absorbance. The results show that the interpretation values of polysaccharides evaluation didn’t bring significant results itself, but in combination with classical tools of geoarchaeology may bring interpretable and new results.
Holocene environmental history of tropical, mid-altitude Lake Ocotalito, México, inferred from ostracodes and non-biological indicators
Authors: Díaz Karen A , Pérez Liseth , Correa-Metrio Alexander , Franco-Gaviria Juan Felipe , Echeverría Paula , Curtis Jason , Brenner Mark
Published: January 2017

This paleolimnological study used ostracodes assemblages, element concentrations, organic and inorganic carbon content, organic C:N ratios, and stable isotope values in valves of the ostracodes Cytheridella ilosvayi as paleoindicators and is the first such investigation from a mid-elevation site in southern México. We provide a ~7600-year (9540–1970 BP) environmental history from karst Lake Ocotalito (920 m a.s.l.), which lies in the Lacandon Forest of Chiapas, México. A 5.4-m sediment core was retrieved from a water depth of 23 m. The main factor that shaped ostracodes species assemblages throughout the Holocene was lake level. A total of six species were identified, and the benthic Cytheridella ilosvayi was dominant. Less abundant species included nektobenthic taxa Cypridopsis okeechobei, Heterocypris putei, and Potamocypris sp. and benthic species Darwinula stevensoni and Pseudocandona sp. Wet conditions, high lake levels (>15 m), and low ostracodes abundances characterized the period between ~9540 and ~7820 BP. From ~7750 to 6460 BP, indicators point to stable conditions and intermediate lake levels (~15 m). Greatest ostracodes abundance and diversity occurred from ~6200 to ~4030 BP, during which mainly drier conditions were inferred, interrupted by short, humid periods. Lower abundances and low Sr and δ18O values characterized the period from ~3810 to ~1970 BP and indicate higher lake levels, that is, wetter conditions. Throughout this period, however, a slight trend toward drier conditions was observed. Comparison with paleolimnological studies in other karst lakes from the region suggests mid-altitude aquatic ecosystems may be more sensitive to climate fluctuations than lakes in the lowlands. For instance, stable isotope records from the Lake Ocotalito core display greater ranges. This, however, may simply reflect inter-lake differences in sensitivity, controlled by lake-specific hydrologic factors. The record from Lake Ocotalito fills an important gap in our knowledge of past biotic diversity, paleoclimate, and paleoenvironmental conditions in the northern Neotropics.
A sensitivity analysis for publication bias in systematic reviews
Authors: Copas J B , Shi J Q
Published: January 2017

There is no simple method of correcting for publication bias in systematic reviews. We suggest a sensitivity analysis in which different patterns of selection bias can be tested against the fit to the funnel plot. Publication bias leads to lower values, and greater uncertainty, in treatment effect estimates. Two examples are discussed. An appendix lists the S-plus code needed for carrying out the analysis.
Approximations for trimmed Fisher procedures in research synthesis
Authors: Olkin Ingram , Saner Hilary
Published: January 2017

When combining the results of independent studies it often happens that some studies are potentially aberrant either in quality or in actual values. Because aberrant studies are often at the extremes, we may wish to trim some of the largest and smallest effects. In such a case the use of p-values may well serve as a diag-nostic method. However, the use of ordered effects changes the distribution of the underlying statistics. We provide a discussion of the exact distribution of the trimmed version of the Fisher procedure. Because of the complexity of the exact distribution, several approximations are presented. These alternatives are applied to a meta-analysis on the effect of the dose of a drug on the risk of mortality.
Bayesian methods in meta-analysis and evidence synthesis
Authors: Sutton Alex J , Abrams Keith R
Published: January 2017

This paper reviews the use of Bayesian methods in meta-analysis. Whilst there has been an explosion in the use of meta-analysis over the last few years, driven mainly by the move towards evidence-based healthcare, so too Bayesian methods are being used increasingly within medical statistics. Whilst in many meta-analysis settings the Bayesian models used mirror those previously adopted in a frequentist formulation, there are a number of specific advantages conferred by the Bayesian approach. These include: full allowance for all parameter uncertainty in the model, the ability to include other pertinent information that would otherwise be excluded, and the ability to extend the models to accommodate more complex, but frequently occurring, scenarios. The Bayesian methods discussed are illustrated by means of a meta-analysis examining the evidence relating to electronic fetal heart rate monitoring and perinatal mortality in which evidence is available from a variety of sources.
An efficient test based on the inferential model for the non-inferiority of odds ratio in matched-pairs design
Authors: Wang Zhining , Jin Hua , Lu Hezhi , Jin Yaolan
Published: January 2017

Non-inferiority of one treatment to another based on odds ratio for the matched-pair design is a common issue in the medical research. Liu et al. derived two asymptotic tests, delta method and score test, which can be applicable for large samples but may tend to be liberal for small sample sizes. Jin et al. proposed an IM-based method that can control the type I risk well but may be somewhat conservative. In this paper, we extend the IM-based method to RIM-based test using the randomized plausibility function. We prove that our new proposed method is not only valid but also efficient. Simulation studies confirm that the RIM-based test is better than other methods. A numerical example illustrates the proposed method.
The play off the stage: the writer-reader relationship in drama
Authors: Feng Zongxin , Shen Dan
Published: January 2017

The writer-reader relationship in drama, with stage directions as part of the dramatic language, is much more complicated than that in other types of literature. The complication mainly comes from the fact that 'the reader' is a kind of collective term covering various types of individuals with different pragmatic roles, including the director, the stage producer, the setting designer, actors/actresses, the audience outside the theatre and ordinary readers. Thus, instead of a one-to-one process of communication between the writer and the reader, there are multiple parallel processes between the writer and various types of readers, with the same play text conveying different pragmatic meanings to different addressees. For instance, a play text is utilitarian in the theatrical circle but fictional in the literary circle, and what is imperative for one type of reader is purely descriptive and narrative for another. For various reasons, this area has so far received little critical attention. This article, from a pragmatic-stylistic perspective and with special reference to Eugène Ionesco's The Lesson, attempts to examine how the playwright's discourse strategies produce different effects on different types of readers.
Jim's language and the issue of race in Huckleberry Finn
Authors: Cohen Minnick Lisa
Published: January 2017

While many critics have considered how Jim is represented in Huckleberry Finn, few have approached the question of how he is characterized via an examination of his speech. This article looks specifically at phonological and grammatical features of Jim's speech to determine whether or not they correspond substantially to features of African-American Vernacular English (AAVE) documented by leading scholars. Using the LinguaLinks software program, it was possible to analyze Jim's speech in its entirety to the point where conclusions about characterization based on his language can conscientiously be made. The idea has been to look for occurrences of AAVE features in order to determine at least anecdotally whether Twain represents Jim's speech authentically, that is, in a way that indicates a real rather than stereotypical awareness of as well as sensitivity to real AAVE. Along with the analysis, the article continues with a discussion of attitudes towards social and regional variation of American English (AAVE in particular), the complexity of the work itself, and the critical and popular responses to it.