bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of rapid tooling using fused deposition modeling: a review
Authors: Boparai Kamaljit Singh , Singh Rupinder , Singh Harwinder
Published: April 2016

Purpose

The purpose of this study is to highlight the direct fabrication of rapid tooling (RT) with desired mechanical, tribological and thermal properties using fused deposition modelling (FDM) process. Further, the review paper demonstrated development procedure of alternative feedstock filament of low-cost composite material for FDM to extend the range of RT applications.

Design/methodology/approach

The alternative materials for FDM and their processing requirements for fabrication in filament form as reported by various researchers have been summarized. The literature demonstrates the role of various post-processing techniques on surface finish of FDM prints. Further, low-cost materials for feedstock filament have been investigated experimentally to check their adaptability/suitability for commercial FDM setup. The approach was to realize the requirements of FDM (melt flow rate, flexibility, stiffness, glass transition temperature and mechanical strength), necessary for the successful run of an alternative filament. The effect of constituents (additives, plasticizers, surfactants and fillers) in polymeric matrix on mechanical, tribological and thermal properties has been investigated.

Findings

It is possible to develop composite material feedstock as filament for commercial FDM setup without changing its hardware and software. Surface finish of the parts can further be improved by applying various post-processing techniques. Most of the composite parts have high mechanical strength, hardness, thermal stability, wear resistant and better bond formation than standard material parts.

Research limitations/implications

Future research may be focused on improving the surface quality of parts fabricated with composite feedstock, solving issues related to the uniform distribution of filled materials during the fabrication of feedstock filament which in turns further increases mechanical strength, high dimensional stability of composite filament and transferring the technology from laboratory scale to various industrial applications.

Practical implications

Potential applications of direct fabrication with RT includes rapid manufacturing (RM) of metal-filled parts and ceramic-filled parts (which have complex shape and cannot be rapidly made by any other manufacturing techniques) in the field of biomedical and dentistry.

Originality/value

This new manufacturing methodology is based on the proper selection and processing of various materials and additives to form high-performance, low-cost composite material feedstock filament (which fulfil the necessary requirements of FDM process). Finally, newly developed feedstock filament material has both quantitative and qualitative advantage in RT and RM applications as compared to standard material filament.
Direct digital manufacturing of an accelerator pedal for a Formula Student racing car
Authors: Prada Jorge Gonzalez , Cazon Aitor , Carda Josu , Aseguinolaza Ander
Published: April 2016

Purpose

This paper aims to focus on the design, analysis and additive manufacturing (AM) with two different technologies of an accelerator pedal for the Formula Student 2014 edition to reduce the weight of the original pedal in aluminium and maintain a reasonable level of performance.

Design/methodology/approach

The new and the original accelerator pedals were modelled in a computer-aided design application, and three finite element simulations were performed for each manufacturing technology to evaluate three different driving scenarios. Later on, two physical prototypes were manufactured using two AM technologies: poly-jet and fused deposition modelling (FDM). With these physical prototypes, static tests were carried out to verify the computational simulations and to determine the fracture load, while dynamic tests, based on an input signal from a real racing scenario, were performed to ensure their technical viability.

Findings

Simulations with poly-jet and FDM printing material show that the new design presents a maximum deformation of 4.8 and 4.09 mm, respectively, under a nominal load of 150N. The results of the static tests with the poly-jet physical prototype showed a maximum displacement of 4.05 mm under a nominal load of 150N, while the ultimate load before fracture was 450N. The FDM prototype reached 3.98 mm under 150N and the ultimate load was 350N. Dynamic tests showed that both pedals were able to withstand four Formula Student “Endurance” events without failure.

Originality/value

This paper states that AM approach is a feasible and economically affordable solution in comparison to exiting solutions with metallic alloys and composite materials when designing and manufacturing accelerator pedal arms for Formula Student competition cars. According to these results, the present research argues that, from a technical point of view, the AM pedals stand at a reasonable level of performance in displacements and stresses. This study suggests that AM pedals could be a viable option that must be considered in professional competitive automobiles.
A novel technique for reducing lead-time and energy consumption in fabrication of Inconel-625 parts by laser-based metal deposition process
Authors: Vinod A.R. , Srinivasa C.K. , Keshavamurthy R. , Shashikumar P.V.
Published: April 2016

Purpose

This paper aims to focus on reducing lead-time and energy consumption for laser-based metal deposition of Inconel-625 superalloy and to investigate the effect of process parameters on microstructure, density, surface roughness, dimensional accuracy and microhardness.

Design/methodology/approach

Inconel material was deposited on steel substrate by varying process parameters such as laser power, laser scan speed and powder flow rate. The deposited parts were characterized for their density, surface roughness, dimensional accuracy and microhardness.

Findings

The study reveals that with increase in laser power, laser scan speed and powder flow rate, there was an increase in density, surface roughness values and microhardness of the deposits, while there was a decrease in dimensional accuracy, deposition time and energy consumption.

Practical implications

The results of this study can be useful in fabrication of Inconel components by laser-based metal deposition process, and the methodology can be expanded to other materials to reduce the lead-time and energy consumption effectively.

Originality/value

The present study gives an understanding of effect of process parameters on density, surface roughness, dimensional accuracy, microhardness, deposition time and energy consumption for laser-based metal deposition of Inconel-625.
Influence of SLS processing parameters according to the new mathematical model on flexural properties
Authors: Pilipović Ana , Valentan Bogdan , Šercer Mladen
Published: April 2016

Purpose

The purpose of this paper is the selection of production parameters in selective laser sintering – SLS for the production of quality products (e.g. good mechanical properties). The manufacturing procedure affects the properties, which is especially significant in additive procedures, as the products are not cheap and the procedure and material need to be optimally selected.

Design/methodology/approach

The paper presents an analysis of the fabrication parameters in selective laser sintering (SLS) that affect the flexural properties of the finished product.

Findings

The influence of a new parameter has been found, the overlay ratio, and using the mathematical and scheme method, the selection of parameters for obtaining the optimal flexural properties has been proposed.

Originality/value

The paper presents a new mathematical model for the calculation of the processing parameters in SLS of polymer products and gives a diagram for the determination of which parameters are the best to use for practical purposes.
Using camera trapping and hierarchical occupancy modelling to evaluate the spatial ecology of an African mammal community
Authors: Rich Lindsey N. , Miller David A.W. , Robinson Hugh S. , McNutt J. Weldon , Kelly Marcella J.
Published: April 2016

Emerging conservation paradigms have shifted from single to multi‐species approaches focused on sustaining biodiversity. Multi‐species hierarchical occupancy modelling provides a method for assessing biodiversity while accounting for multiple sources of uncertainty.

We analysed camera trapping data with multi‐species models using a Bayesian approach to estimate the distributions of a terrestrial mammal community in northern Botswana and evaluate community, group, and species‐specific responses to human disturbance and environmental variables. Groupings were based on two life‐history traits: body size (small, medium, large and extra‐large) and diet (carnivore, omnivore and herbivore).

We photographed 44 species of mammals over 6607 trap nights. Camera station‐specific estimates of species richness ranged from 8 to 27 unique species, and species had a mean occurrence probability of 0·32 (95% credible interval = 0·21–0·45). At the community level, our model revealed species richness was generally greatest in floodplains and grasslands and with increasing distances into protected wildlife areas.

Variation among species’ responses was explained in part by our species groupings. The positive influence of protected areas was strongest for extra‐large species and herbivores, while medium‐sized species actually increased in the non‐protected areas. The positive effect of grassland/floodplain cover, alternatively, was strongest for large species and carnivores and weakest for small species and herbivores, suggesting herbivore diversity is promoted by habitat heterogeneity.

Synthesis and applications. Our results highlight the importance of protected areas and grasslands in maintaining biodiversity in southern Africa. We demonstrate the utility of hierarchical Bayesian models for assessing community, group and individual species’ responses to anthropogenic and environmental variables. This framework can be used to map areas of high conservation value and predict impacts of land‐use change. Our approach is particularly applicable to the growing number of camera trap studies world‐wide, and we suggest broader application globally will likely result in reduced costs, improved efficiency and increased knowledge of wildlife communities.
Do space‐for‐time assessments underestimate the impacts of logging on tropical biodiversity? An Amazonian case study using dung beetles
Authors: França Filipe , Louzada Julio , Korasaki Vanesca , Griffiths Hannah , Silveira Juliana M. , Barlow Jos
Published: April 2016

Human alteration of the global environment is leading to a pervasive loss of biodiversity. Most studies evaluating human impacts on biodiversity occur after the disturbance has taken place using spatially distinct sites to determine the undisturbed reference condition. This approach is known as a space‐for‐time (SFT) substitution. However, SFT substitution could be underestimating biodiversity loss if spatial controls fail to provide adequate inferences about pre‐disturbance conditions.

We compare the SFT substitution with a before–after control–impact (BACI) approach by assessing dung beetles before and after a logging exploration in the Brazilian Amazon. We sampled 34 logging management units, of which 29 were selectively logged with different intensities after our first collection. We used dung beetle species richness, species composition and biomass as our biodiversity response metrics and the gradient of selective logging intensity as our explanatory metric.

Only the BACI approach consistently demonstrated the negative impacts of logging intensification on all dung beetle community metrics. Moreover, the BACI approach explained significantly more of the variance in all the relationships and it doubled the estimates of species loss along the gradient of logging intensity when compared to SFT.

Synthesis and applications. Our results suggest that space‐for‐time (SFT) substitution may greatly underestimate the consequences on local species diversity and community turnover. These results have important implications for researchers investigating human impacts on biodiversity. Incentivizing before–after control–impact (BACI) approaches will require longer‐term funding to gather the data and stronger links between researchers and landowners. However, BACI approaches are accompanied by many logistical constraints, making the continued use of SFT studies inevitable in many cases. We highlight that non‐significant results and weak effects should be viewed with caution.
Drought history affects grassland plant and microbial carbon turnover during and after a subsequent drought event
Authors: Fuchslueger Lucia , Bahn Michael , Hasibeder Roland , Kienzl Sandra , Fritz Karina , Schmitt Michael , Watzka Margarete , Richter Andreas
Published: April 2016

Drought periods are projected to become more severe and more frequent in many European regions. While effects of single strong droughts on plant and microbial carbon (C) dynamics have been studied in some detail, impacts of recurrent drought events are still little understood.

We tested whether the legacy of extreme experimental drought affects responses of plant and microbial C and nitrogen (N) turnover to further drought and rewetting. In a mountain grassland, we conducted a 13C pulse‐chase experiment during a naturally occurring drought and rewetting event in plots previously exposed to experimental droughts and in ambient controls (AC). After labelling, we traced 13C below‐ground allocation and incorporation into soil microbes using phospholipid fatty acid biomarkers.

Drought history (DH) had no effects on the standing shoot and fine root plant biomass. However, plants with experimental DH displayed decreased shoot N concentrations and increased fine root N concentrations relative to those in AC. During the natural drought, plants with DH assimilated and allocated less 13C below‐ground; moreover, fine root respiration was reduced and not fuelled by fresh C compared to plants in AC.

Regardless of DH, microbial biomass remained stable during natural drought and rewetting. Although microbial communities initially differed in their composition between soils with and without DH, they responded to the natural drought and rewetting in a similar way: gram‐positive bacteria increased, while fungal and gram‐negative bacteria remained stable. In soils with DH, a strongly reduced uptake of recent plant‐derived 13C in microbial biomarkers was observed during the natural drought, pointing to a smaller fraction of active microbes or to a microbial community that is less dependent on plant C.

Synthesis. Drought history can induce changes in above‐ vs. below‐ground plant N concentrations and affect the response of plant C turnover to further droughts and rewetting by decreasing plant C uptake and below‐ground allocation. DH does not affect the responses of the microbial community to further droughts and rewetting, but alters microbial functioning, particularly the turnover of recent plant‐derived carbon, during and after further drought periods.
Isolation of isoprene degrading bacteria from soils, development of isoA gene probes and identification of the active isoprene‐degrading soil community using DNA‐stable isotope probing
Authors: El Khawand Myriam , Crombie Andrew T. , Johnston Antonia , Vavlline Dmitrii V. , McAuliffe Joseph C. , Latone Jacob A. , Primak Yuliya A. , Lee Sang‐Kyu , Whited Gregg M. , McGenity Terry J. , Murrell J. Colin
Published: April 2016

Emissions of biogenic volatile organic compounds (bVOCs), are an important element in the global carbon cycle, accounting for a significant proportion of fixed carbon. They contribute directly and indirectly to global warming and climate change and have a major effect on atmospheric chemistry. Plants emit isoprene to the atmosphere in similar quantities to emissions of methane from all sources and each accounts for approximately one third of total VOCs. Although methanotrophs, capable of growth on methane, have been intensively studied, we know little of isoprene biodegradation. Here, we report the isolation of two isoprene‐degrading strains from the terrestrial environment and describe the design and testing of polymerase chain reaction (PCR) primers targeting isoA, the gene encoding the active‐site component of the conserved isoprene monooxygenase, which are capable of retrieving isoA sequences from isoprene‐enriched environmental samples. Stable isotope probing experiments, using biosynthesized 13C‐labelled isoprene, identified the active isoprene‐degrading bacteria in soil. This study identifies novel isoprene‐degrading strains using both culture‐dependent and, for the first time, culture‐independent methods and provides the tools and foundations for continued investigation of the biogeography and molecular ecology of isoprene‐degrading bacteria.
The algicidal activity of Aeromonas sp. strain GLY‐2107 against bloom‐forming Microcystis aeruginosa is regulated by N‐acyl homoserine lactone‐mediated quorum sensing
Authors: Guo Xingliang , Liu Xianglong , Wu Lishuang , Pan Jianliang , Yang Hong
Published: April 2016

Cyanobacterial blooms have disrupted the efficient utilization of freshwater worldwide. A new freshwater bacterial strain with strong algicidal activity, GLY‐2107, was isolated from Lake Taihu and identified as Aeromonas sp. It produced two algicidal compounds: 2107‐A (3‐benzyl‐piperazine‐2,5‐dione) and 2107‐B (3‐methylindole). Both compounds exhibited potent algicidal activities against Microcystis aeruginosa, the dominant bloom‐forming cyanobacterium in Lake Taihu. The EC50 values (concentration for 50% maximal effect) of 3‐benzyl‐piperazine‐2,5‐dione and 3‐methylindole were 4.72 and 1.10 μg ml−1 respectively. Based on a thin‐layer chromatography biosensor assay and ultra‐performance liquid chromatography‐coupled high resolution‐tandem mass spectrometry (UPLC‐HRMS/MS), the N‐acyl homoserine lactone (AHL) profile of strain GLY‐2107 was identified as two short side‐chain AHLs: N‐butyryl‐homoserine lactone (C4‐HSL) and N‐hexanoyl‐homoserine lactone (C6‐HSL). The production of the two algicidal compounds was controlled by AHL‐mediated quorum sensing (QS), and C4‐HSL was the key QS signal for the algicidal activity of the strain GLY‐2107. Moreover, 3‐methylindole was found to be positively regulated by C4‐HSL‐mediated QS, whereas 3‐benzyl‐piperazine‐2,5‐dione might be negatively controlled by C4‐HSL‐mediated QS. This study suggests that a QS‐regulated algicidal system may have potential use for the development of a novel control strategy for harmful cyanobacterial blooms.
An indoleacetate‐CoA ligase and a phenylsuccinyl‐CoA transferase involved in anaerobic metabolism of auxin
Authors: Schühle Karola , Nies Jonas , Heider Johann
Published: April 2016

The plant hormone auxin (indoleacetate) is anaerobically degraded by the Betaproteobacterium Aromatoleum aromaticum. We report here on a CoA ligase (IaaB) and a CoA‐transferase (IaaL) which are encoded in the apparent substrate‐induced iaa operon containing genes for indoleacetate degradation. IaaB is a highly specific indoleacetate‐CoA ligase which activates indoleacetate to the CoA‐thioester immediately after uptake into the cytoplasm. This enzyme only activates indoleacetate and some closely related compounds such as naphthylacetate, phenylacetate and indolepropionate, and is inhibited by high concentrations of substrates, and by the synthetic auxin compound 2,4‐dichlorophenoxyacetate, which does not serve as substrate. IaaL is a CoA‐transferase recognizing several C4‐dicarboxylic acids, such as succinate, phenylsuccinate or benzylsuccinate and their CoA‐thioesters, but only few monocarboxylic acids and no C3‐dicarboxylic acids such as benzylmalonate. The enzyme shows no stereospecific discrimation of the benzylsuccinate enantiomers. Moreover, benzylsuccinate is regiospecifically activated to 2‐benzylsuccinyl‐CoA, whereas phenylsuccinate is converted to an equal mixture of both regioisomers (2‐ and 3‐phenylsuccinyl‐CoA). The identification of these two enzymes allows us to set up a modified version of the metabolic pathway of anaerobic indoleacetate degradation and to investigate the sequences databases for the occurrence and distribution of this pathway in other microorgansisms.
Extension and the Disposal of the World: Double-Crossing Systems, Culture, Self and Language
Authors: Munro Rolland
Published: April 2016

Long indexed by sociological ideas of structure, the notion of extension is yet disparate and poorly disseminated – as evidenced by popular motifs such as ‘the world is at our disposal’ eschewing notions of emplacement and embeddedness and instead championing choice and individualised agency. On the assumption that this lacunae relates in part to paradigm debates over incommensurability, the proposal in this inaugural lecture is to explore double-crossing as a methodological device by which to draw insights on extension from major ‘gatherings’ of Euro-American thought, while respecting the orderings, institutional arrangements, situations and networks each approach imposes.

In retracing the ‘disposal’ of the world through four theoretical perspectives germane to sociology – namely systems, culture, self and language – the objective is to illustrate the methodology of double crossing. Drawing on both my work on social and cultural theory and my field studies in market leaders, I first show how moving back and forth between the older and newer ground within each perspective helps to elicit what gets unsighted from either view. Secondly, inasmuch as the usual way of ‘making a clearing’ is argued as caught ‘in reaction’ from extant theory (ending up say talking of parts instead of wholes or consumption in place of production), I advance the methodology of double-crossing by excavating the recessive arrangements and ordering implicit in each perspective and so illuminate the different ways extension is affected by how world is imagined and experienced.
Neurodevelopmental outcomes in children in relation to placental abruption
Authors: Ananth CV , Friedman AM , Lavery JA , VanderWeele TJ , Keim S , Williams MA
Published: April 2016

Objective

Placental abruption has a profound impact on perinatal mortality, but implications for neurodevelopment during childhood remain unknown. We examined the association between abruption and neurodevelopment at 8 months and 4 and 7 years and evaluated the extent to which these associations were mediated through preterm delivery.

Design

Secondary analysis of a multicenter prospective cohort study.

Setting

Multicenter US National Collaborative Perinatal Project (1959–76).

Population

Women that delivered singleton live births.

Methods

Analyses of IQ scores were based on marginal structural models (MSM) to account for losses to follow‐up. We also carried out a causal mediation analysis to evaluate if the association between abruption and cognitive deficits was mediated through preterm delivery, and performed a sensitivity analysis for unobserved confounding.

Main outcome measures

We evaluated cognitive development based on the Bayley scale at 8 months (Mental and Motor Scores), and intelligent quotient (IQ) based on the Stanford–Binet scale at 4 years and the Wechsler Intelligence Scale for Children at 7 years.

Results

The confounder and selection‐bias adjusted risk ratio (RR) of abnormal 8‐month Motor and Mental assessments were 2.35 (95%CI 1.39, 3.98) and 2.03 (95%CI 1.13, 3.64), respectively, in relation to abruption. The associations at 4 years were attenuated and resolved at 7 years. The proportion of children with abruption‐associated neurological deficits mediated through preterm delivery ranged from 27 to 75%. Following adjustment for unobserved confounding the proportion mediated through preterm delivery was attenuated.

Conclusion

The effect of abruption on neurodevelopmental outcomes appears restricted to an effect that is largely mediated through preterm delivery.

Tweetable abstract

Increased risk of cognitive deficits in relation to abruption appears to be mediated through preterm delivery.
A Meta‐Analysis of Enriched Pasta: What Are the Effects of Enrichment and Process Specifications on the Quality Attributes of Pasta?
Authors: Mercier Samuel , Moresoli Christine , Mondor Martin , Villeneuve Sébastien , Marcos Bernard
Published: April 2016

Pasta products enriched with ingredients to improve their nutritional value or functionality have become increasingly popular, and substantial research efforts have been directed towards the development of new enriched pasta products. In this work, a meta‐analysis was conducted to quantify the impact of enrichment and process specifications on the quality attributes of pasta. A literature search revealed 66 studies on enriched pasta. Process specifications and quality attributes, namely proximate composition, dough, drying, cooking, and mechanical properties, color, and sensory attributes, were extracted from the studies and compiled in a data set. Analysis of the data set revealed significant differences between pasta enriched with high‐fiber ingredients and pasta enriched with pulse flour. High‐fiber ingredients generally preserved the quality attributes of pasta more effectively than pulse flour. Comparisons based on the drying temperature showed that high drying temperatures generally improve the cooking properties of enriched pasta. Sensory evaluations indicated that enrichment levels below 10% generally do not affect consumer acceptance, but higher enrichment levels significantly decrease it. Pearson correlation coefficients showed that the gelatinization temperature and Farinograph properties are useful indicators of the mechanical properties and sensory attributes of pasta. The meta‐analysis revealed the need to better understand the impact of the processing history of the enrichment ingredient on the quality attributes and the health benefits of enriched pasta.
Changing the Ties that Bind
Authors: Mowen Thomas J. , Visher Christy A.
Published: April 2016

Research Summary

By using a subsample of the Returning Home data set, we explored how family relationships change during reentry as a result of incarceration. Overall, we found that individuals who completed parenting classes, those with more frequent visits from family members, and Black and female respondents experienced positive changes in family relationships. On the other hand, single and divorced individuals, those with prior convictions and mental health issues, and individuals who reported barriers to family contact reported significant negative changes within the family relationship.

Policy Implications

The findings from this study suggest that reducing barriers to family contact—especially the cost of visitation and visitation procedures—may lead to positive changes within family relationships for formerly incarcerated individuals. Furthermore, developing programs to assist individuals with mental health issues to maintain family relationships may create avenues to help those individuals keep, or reestablish, family ties after release.
Effects of Vacuum Impregnation with Sucrose Solution on Mango Tissue
Authors: Lin Xian , Luo Cailian , Chen Yulong
Published: April 2016

The influences of vacuum impregnation (VI) on the tissue of mango cubes during atmospheric immersion in sucrose solution were investigated. Results showed that VI effectively facilitated water loss (WL) and sugar gain (SG) during the 300min immersion process, with increases of 20.59% and 31.26%, respectively. A pectin solubilization/degradation phenomenon was observed in the immersion process. The intercellular space and cross section area in the VI‐treated mango tissue increased immediately after being released to atmospheric pressure. And it was noted that after experiencing shrinkage‐relaxation period twice in the 300 min immersion process, the size of VI‐treated mango cells recovered to the original level of fresh ones. Major variations in WL, protopectin content, water soluble pectin content, firmness and microstructure of mango cubes appeared within the first 60 min. In addition, the firmness of mango cubes was positively correlated with the protopectin content (P < 0.01), but negatively correlated with WL and the water soluble pectin content (P < 0.01), indicating that WL and degradation of protopectin contributed greatly to the loss of firmness.
Identification of Putative Geographically Isolated Wetlands of the Conterminous United States
Authors: Lane Charles R. , D'Amico Ellen
Published: April 2016

Geographically isolated wetlands (GIWs) are wetlands completely surrounded by uplands. While common throughout the United States (U.S.), there have heretofore been no nationally available, spatially explicit estimates of GIW extent, complicating efforts to understand the myriad biogeochemical, hydrological, and habitat functions of GIWs and hampering conservation and management efforts at local, state, and national scales. We used a 10‐m geospatial buffer as a proxy for hydrological or ecological connectivity of National Wetlands Inventory palustrine and lacustrine wetland systems to nationally mapped and available stream, river, and lake data. We identified over 8.3 million putative GIWs across the conterminous U.S., encompassing nearly 6.5 million hectares of wetland resources (average size 0.79 ± 4.81 ha, median size 0.19 ha). Putative GIWs thus represent approximately 16% of the freshwater wetlands of the conterminous U.S. The water regime for the majority of the putative GIWs was temporarily or seasonally flooded, suggesting a vulnerability to ditching or hydrologic abstraction, sedimentation, or alterations in precipitation patterns. Additional analytical applications of this readily available geospatially explicit mapping product (e.g., hydrological modeling, amphibian metapopulation, or landscape ecological analyses) will improve our understanding of the abundance and extent, effect, connectivity, and relative importance of GIWs to other aquatic systems of the conterminous U.S.
Welfare‐increasing third‐degree price discrimination
Authors: Cowan Simon
Published: April 2016

When demand functions in different markets are derived from distributions of reservation prices that differ only in their means, conditions exist such that third‐degree price discrimination leads to greater total output and greater total welfare. Welfare is higher with discrimination than with a uniform price when demand functions are derived from logistic distributions with different means. Welfare and consumer surplus are higher with discrimination for demands derived from a distribution related to the Pareto. In general, whether discrimination increases total output depends on demand being more convex in markets in which prices fall with discrimination than in those in which prices rise.
Measuring consumer switching costs in the television industry
Authors: Shcherbakov Oleksandr
Published: April 2016

In this article, I develop and estimate a model of dynamic consumer behavior with switching costs in the market for paid‐television services. I estimate the parameters of the structural model using data on cable and satellite systems across local US television markets over the period 1992–2006. The results suggest switching costs range from $159 to $242 for cable and from $212 to $276 for satellite providers in 1997 dollars. Using a simple dynamic model of cable providers, I demonstrate that switching costs of these magnitudes can significantly affect the firms' optimal strategies.
Valorising the Samad Late Iron Age
Authors: Yule Paul Alan
Published: April 2016

The Late Iron Age (LIA) in Central Oman is known from the eponymous site of Samad al‐Shān as well as al‐Moyassar (formerly al‐Maysar), which teams from Bochum and Heidelberg investigated from 1977 to 1996 in twelve campaigns. The chronology of this little known period has evoked much controversy but although this contribution contains critical comments, these regard mostly smaller issues or details and there is a general unspoken agreement about the basic chronological issues. The present study adds both new and old unpublished documentation to the discussion. What follows includes a re‐examination of the original documentation of M42 and M43 sites which confirms the excavators' chronology. New LIA sites are added. M. Mouton's attempted deconstruction of the existing chronology and his new combined definition of the PIR and Samad LIA assemblages rest on slight inconsistencies in the original al‐Moyassar site report of 1981. Despite the spotty nature of our sources, Oman's latest prehistoric facies shows a distinctive character separate from that known principally in the United Arab Emirates (UAE).
Hafit tombs in ash‐Sharqiyah, Oman: assessing the accuracy and precision of Google Earth remote‐sensing survey and analysing their distribution in the landscape
Authors: Deadman William M. , Al‐Jahwari Nasser Said
Published: April 2016

Google Earth and high‐resolution satellite imagery provide a means of carrying out remote‐sensing survey of Hafit tombs able to cover large areas in short periods of time. While the potential of such research has already been demonstrated in the Wādī Andam area, the accuracy and precision of the methodology are not yet clear. A ground survey carried out by a Sultan Qaboos University (SQU) team in western Ja'alan provides an excellent control to assess the efficacy of the method. The study area was surveyed using Google Earth, and the two datasets were compared. Hafit tombs were identified to a high level of accuracy, but approximately 50% of the structures were not visible, with badly preserved tombs more likely to be missed than those in good condition. Remote sensing can be used in the preliminary stages of survey or more generally to discover and analyse broad patterns of Hafit tomb distribution. Comparisons of the distribution of Hafit tombs in western Ja'alan and Wādī Andam reveal clear similarities: the structures occupy elevated positions adjacent to sizeable wadi channels. The density of tombs is much greater in the western Ja'alan study area, which may suggest that Wādī Batha supported a larger Hafit population than Wādī Andam.
Silver production at al‐Radrad: archaeometallurgical analysis of ore, slag and technical ceramics from early medieval Yemen
Authors: Merkel Stephen , Hauptmann Andreas , Kirnbauer Thomas , Téreygeol Florian
Published: April 2016

The zinc‐lead‐silver deposit of al‐Jabali, about 65 km north‐east of Sana'a in Yemen, has been identified as the location of the late antique/Islamic period silver mine al‐Radrad. Exploitation of the mine is known from the account of al‐Hamdani, an Arab geographer of the tenth centuryAD. The al‐Jabali area has been the focus of geological and archaeometallurgical surveys, and extensive metallurgical remains have been discovered. Samples of ore, slag and technical ceramics were collected for archaeometallurgical analysis. The technology of silver production is discussed in relation to the historical record, and elemental and lead isotope characterisation of ore and slag provides a basis for future provenance studies.
An Aramaic−Hasaitic bilingual inscription from a monumental tomb at Mleiha, Sharjah, UAE
Authors: Overlaet Bruno , Macdonald Michael , Stein Peter
Published: April 2016

Excavations of a monumental tomb in Area F at Mleiha have revealed a lime‐plaster funerary stele with an Aramaic and Hasaitic inscription. The excavation of the tomb was not completed but a preliminary report on the tomb and a discussion of the text is presented. The inscription states that the tomb was built by the deceased's son and mentions the date and his name, family lineage and function in the service of the King of ʿUmān.
Similar white matter but opposite grey matter changes in schizophrenia and high‐functioning autism
Authors: Katz J. , d'Albis M.‐A. , Boisgontier J. , Poupon C. , Mangin J.‐F. , Guevara P. , Duclap D. , Hamdani N. , Petit J. , Monnet D. , Le Corvoisier P. , Leboyer M. , Delorme R. , Houenou J.
Published: April 2016

Objective

High‐functioning autism (HFA) and schizophrenia (SZ) are two of the main neurodevelopmental disorders, sharing several clinical dimensions and risk factors. Their exact relationship is poorly understood, and few studies have directly compared both disorders. Our aim was thus to directly compare neuroanatomy of HFA and SZ using a multimodal MRI design.

Methods

We scanned 79 male adult subjects with 3T MRI (23 with HFA, 24 with SZ and 32 healthy controls, with similar non‐verbal IQ). We compared them using both diffusion‐based whole‐brain tractography and T1 voxel‐based morphometry.

Results

HFA and SZ groups exhibited similar white matter alterations in the left fronto‐occipital inferior fasciculus with a decrease in generalized fractional anisotropy compared with controls. In grey matter, the HFA group demonstrated bilateral prefrontal and anterior cingulate increases in contrast with prefrontal and left temporal reductions in SZ.

Conclusion

HFA and SZ may share common white matter deficits in long‐range connections involved in social functions, but opposite grey matter abnormalities in frontal regions that subserve complex cognitive functions. Our results are consistent with the fronto‐occipital underconnectivity theory of HFA and the altered connectivity hypothesis of SZ and suggest the existence of both associated and diametrical liabilities to these two conditions.
Effect of host plants on the development, survivorship and reproduction of Grapholita molesta (Lepidoptera: Tortricidae) under laboratory conditions
Authors: Yang Xiao‐fan , Fan F. , Ma Chun‐seng , Wang Chong , Wei Guo‐shu
Published: April 2016

To seek sufficient resources for growth, survival and reproduction, most insect species must tackle host selection problems. The development, survivorship and fecundity of the oriental fruit moth Grapholita molesta (Busck) on apricot Prunus armeniaca L., plum Prunus salicina L., nectarine Prunus persica var. nectarina L. Batsch, peach Prunus persica L., pear Pyrus sorotina Will. and apple Malus domestica Mill. were determined to test host suitability in the laboratory. Larval development rate was faster, and survival rate was higher on plum and nectarine compared with the other fruits. Adult longevity and the duration of oviposition were significantly longer on nectarine. Adult fecundity varied significantly among the tested host plants, with the highest fecundity being observed on apple (135.63 eggs/female), followed by pear (104.90 eggs/female). The intrinsic rate of increase (rm) was greater on pear and apple (0.1574 and 0.1221 eggs per female per day, respectively). Different abilities to develop and reproduce on various host plants partly explain the seasonal host selection of G. molesta.
Allergic rhinoconjunctivitis continued to increase in Swedish children up to 2007, but asthma and eczema levelled off from 1991
Authors: Hicke‐Roberts Anna , Åberg Nils , Wennergren Göran , Hesselmar Bill
Published: April 2016

Aim

This study investigated whether allergies among schoolchildren increased in Sweden between 1979 and 2007 and whether the geographical differences observed in previous studies remained.

Methods

We collected questionnaire data on asthma, allergic rhinoconjunctivitis (ARC) and eczema in children aged seven to eight years from Mölndal, Gothenburg, in south‐western Sweden and Kiruna in northern Sweden in 1979 (n = 4682), 1991 (n = 2481) and 2007 (n = 1029). The same regions and questions were used in all three studies, and extra questions on food allergy or intolerance were added in 2007.

Results

In 1979, 1991 and 2007, the total prevalence of asthma was 2.5%, 5.7% and 7.1%, ARC was 5.5%, 8.1% and 11.1% and eczema was 7.1%, 18.3% and 19.7%, respectively. Asthma prevalence remained higher in Kiruna, but no significant regional differences were seen for ARC and eczema. Almost 20% reported a history of food allergy or intolerance, with a higher prevalence in Kiruna. The allergy risk was reduced if both parents were born outside Sweden.

Conclusion

The prevalence of ARC continued to increase between 1991 and 2007, but increases in asthma and eczema started to level off in 1991. Some geographical differences remained, but total allergy rates were similar in Kiruna and Mölndal in 2007.
The ongoing quandary of defining the standard of care for neonates
Authors: Fanaroff Avroy A. , Fanaroff Jonathan M.
Published: April 2016

Despite extensive use of the term ‘standard of care’ (SOC), there is no such medical definition. How are neonatal therapies accepted as SOC with huge centre‐to‐centre variation? What defines SOC? We will consider paths to acceptance of multiple therapies (antenatal corticosteroids, preventing GBS, others). We conclude single‐centre trials drive care, but are not consistently predictive for multicentre trials. Innovation/quality improvement initiatives also alter care, despite strong evidence practice changes take time. Furthermore, there are powerful medico‐legal implications if a therapy is designated SOC.

Conclusion

Defining SOC is a quandary with more legal implications than medical, but what's most critical is keeping current in a rapidly changing field.
Using a high‐flow nasal cannula provided superior results to low‐flow oxygen delivery in moderate to severe bronchiolitis
Authors: Milani Gregorio P. , Plebani Anna M. , Arturi Elisa , Brusa Danila , Esposito Susanna , Dell'Era Laura , Laicini Emanuela A. , Consonni Dario , Agostoni Carlo , Fossali Emilio F.
Published: April 2016

Aim

An observational study was carried out on infants with moderate to severe bronchiolitis to compare the clinical outcomes following treatment with a high‐flow nasal cannula (HFNC) or standard low‐flow oxygen.

Methods

We enrolled subjects below 12 months of age who were affected by their first bronchiolitis episode. Non‐formal randomisation, based on HFNC availability, was used to assign subjects to either the HFNC or standard oxygen groups. Respiratory rate, respiratory effort and the ability to feed were compared between the two groups at enrolment and at regular time points. The oxygen requirements and the length of hospital stay were also analysed.

Results

Overall, 36 of the 40 enrolled infants completed the study: 18 treated with HFNC (mean age 3.2 months, range 1.2–5.4 months) and 18 with low‐flow oxygen delivery (mean age 3.6 months, range 1.3–5.0 months). Improvements in the respiratory rate, respiratory effort and ability to feed were significantly faster in the HFNC group than the low‐flow oxygen group. The HNFC group needed oxygen supplementation for two days less than the other group and hospital stays were three days shorter.

Conclusion

HFNC provided superior clinical outcomes for infants under 12 months with moderate‐to‐severe bronchiolitis compared to low‐flow oxygen.
Expression of Wntless in colorectal carcinomas is associated with invasion, metastasis, and poor survival
Authors: Xu Hanfeng , Jiang Wen , Zhu Fang , Zhu Chuandong , Wei Juan , Wang Jiandong
Published: April 2016

Wntless also known as WLS, GPR177, or Evi, is a key modulator of Wnt protein secretion. Its overexpression is found in certain types of human cancers such as malignant astrocytoma and breast cancers. We hypothesized that this protein may be aberrantly expressed in colorectal carcinoma which also possesses aberrant Wnt signaling. To investigate the association between the expression of Wnt and clinicopathological parameters in colorectal carcinomas, a set of colorectal carcinoma tissue samples was analyzed for the expression of WLS using an anti‐GPR177 monoclonal antibody specific for the WLS protein. High expression of WLS protein was observed in most colorectal carcinoma samples compared with nontumor mucosa in the same patients (117/201, 58.2%). High expression of WLS was associated with sex (p = 0.005), age (p = 0.009), depth of invasion (p < 0.001), lymph node metastasis (p = 0.026), and tumor‐node‐metastasis (TNM) stage (p = 0.003). No significant relationship between the expression of WLS and tumor location, size, and differentiation was found. The survival analyses showed WLS was an independent prognostic marker and that patients whose carcinoma exhibited high expression of WLS had a poorer outcome (p = 0.033). Our results indicate that WLS may play a role in invasion and metastasis of colorectal carcinoma. The WLS protein expression level may be used as a potential prognostic marker in colorectal carcinoma. Furthermore, the WLS gene may provide a novel target for therapy of colorectal carcinoma.
Prevalence of Dientamoeba fragilis, Giardia duodenalis, Entamoeba histolytica/dispar, and Cryptosporidium spp in Da Nang, Vietnam, detected by a multiplex real‐time PCR
Authors: Ögren Jessica , Van Nguyen Song , Nguyen Minh Khac , Dimberg Jan , Matussek Andreas
Published: April 2016

We surveyed the prevalence of Dientamoeba fragilis, Giardia duodenalis, Entamoeba histolytica, Entamoeba dispar, and Cryptosporidium spp in individuals with and without gastrointestinal (GI) symptoms residing in and around Da Nang city, Vietnam. Fecal samples were collected from children (n = 100) and adults (n = 80) with GI symptoms and from healthy individuals (n = 88) reporting no GI symptoms. Parasite detection was performed by multiplex real‐time PCR. Overall, except for G. duodenalis, we found a low prevalence (<5%) of D. fragilis and E. dispar and no detection of E. histolytica and C. spp in all participants with GI symptoms. Specifically for D. fragilis this contrasts with findings in European populations of children with GI symptoms showing prevalence up to 73%. Moreover, our results indicate that the prevalence of G. duodenalis is higher in patients with GI symptoms compared to asymptomatic individuals and this difference is most obvious in young patients.
Polyphenol intake from a Mediterranean diet decreases inflammatory biomarkers related to atherosclerosis: a substudy of the PREDIMED trial
Authors: Medina‐Remón Alexander , Casas Rosa , Tressserra‐Rimbau Anna , Ros Emilio , Martínez‐González Miguel A. , Fitó Montserrat , Corella Dolores , Salas‐Salvadó Jordi , Lamuela‐Raventos Rosa M. , Estruch Ramón ,   on behalf of the PREDIMED Study Investigators
Published: April 2016

High dietary polyphenol intake is associated with reduced all‐cause mortality and a lower incidence of cardiovascular events. However, the mechanisms involved are not fully understood. The aim of the present substudy of the PREvención con DIetaMEDiterránea (Prevention with Mediterranean diet; PREDIMED) trial was to analyse the relationship between polyphenol intake measured by total urinary polyphenol excretion (TPE), and circulating inflammatory biomarkers and cardiovascular risk factors in elderly individuals. A substudy of 1139 high‐risk participants was carried out within the PREDIMED trial. The subjects were randomly assigned to a low‐fat control diet or to two Mediterranean diets, supplemented with either extra‐virgin olive oil or nuts. Dietary intake, anthropometric data, clinical and laboratory assessments, including inflammatory biomarkers, and urinary TPE were measured at baseline and after the one‐year intervention. Participants in the highest tertile of changes in urinary TPE (T3) showed significantly lower plasma levels of inflammatory biomarkers [vascular cell adhesion molecule 1 (VCAM‐1) (–9.47 ng ml–1), intercellular adhesion molecule 1 (–14.71 ng ml–1), interleukin 6 (–1.21 pg ml–1), tumour necrosis factor alpha (–7.05 pg ml–1) and monocyte chemotactic protein 1 (–3.36 pg ml–1)] than those inthe lowest tertile (T1, P < 0.02; all). A significant inverse correlation existed between urinary TPE and the plasma concentration of\VCAM‐1 (r = –0.301; P < 0.001). In addition, systolic and diastolic blood pressure (BP) decreased and plasma high‐density lipoprotein cholesterol increased in parallel with increasing urinary TPE (T3 vs. T1) (P < 0.005 and P = 0.004, respectively). Increases in polyphenol intake measured as urinary TPE are associated with decreased inflammatory biomarkers, suggesting a dose‐dependent anti‐inflammatory effect of polyphenols. In addition, high polyphenol intake improves cardiovascular risk factors– mainly BP and the lipid profile.