bluuebunny/crossref_metadata_2025 huggingface dataset:
Hybrid Modelling and Optimization of the Oblique Cutting of AISI 1045 Steel
Authors: Perdomo Iván La Fé , Quiza Ramón , Rivas Marcelino , Ramtahalsing Veena
Published: August 2018

Optimization is a very important issue in mechanical industry, especially in machining processes, where different aspects must be considered. Thus, selecting the most proper cutting conditions plays a key role for obtaining efficient and competitive products. This article proposes a hybrid approach for modelling and optimizing the oblique turning processes. Analytical modelling and statistical regressions are combined for predicting the values of the most important parameters involved in the oblique cutting process. The predictions of the model were validated by using experimental data, showing coincidence for a 95%-confidence level. Then, an a posteriori multi-objective optimization is carried out by using a genetic algorithm. Two important and conflicting objectives are simultaneously considered: unit cutting time and tool wear rate, which describe the productivity and tool waste, respectively. The outcome of the optimization process is a set of non-dominated solutions, which are optimal in the wide sense that no other solution in the search space can improve one objective without worsen the other one. Finally, the decision-maker chooses the most convenient solution depending on the actual workshop conditions.
Microstructure and Mechanical Properties of Metal Powder Treated AISI-430 FSS Welds
Authors: Amuda M.O.H. , Lawal F.T. , Onitiri M. A. , Akinlabi E. T. , Mridha S.
Published: August 2018

An innovative yet simple technique for the inoculation of the weld pool of commercial AISI 430 Ferritic Stainless Steel (FSS) with metal powders for grain refinement is discussed. Aluminum or titanium powder in varying amounts introduced into the weld pool via a powder preplacement technique was melted under a tungsten inert gas (TIG) torch. This strategy of inoculating the welds offers dual benefits of grain refinement and constriction in the weld geometry. The addition of the metal powders constricts the HAZ by as much as 50% of the conventional weld providing a grain refinement index (GRI) of about 0.8 in titanium powder treated welds. It equally emerged that weld property is not influenced by the grain size alone but equally by the amount of delta ferrite in the microstructure.
Antideterminismo e natureza humana na filosofia de Blaise Pascal
Authors: Pinto Rodrigo Hayasi
Published: August 2018

O objetivo do presente artigo é abordar a concepção antropológica no pensamento do filósofo francês Blaise Pascal, presente em Pensamentos, dando enfoque à postura não determinista em relação ao homem. Nessa obra o autor apresenta o homem como um ser insignificante no interior de um universo infinito, sem a possibilidade de ter uma posição privilegiada no cosmo. Nesse caso, o homem não possui uma situação ontológica que possa conferir certa relevância a ele no interior do universo. Por outro lado, os princípios da esfera prática, segundo o autor, não passam de princípios fabricados pelo hábito, e, nesse sentido, todos os princípios que fundamentam o agir humano não devem ser considerados naturais e necessários de modo absoluto. Diante desse quadro, é possível perceber na filosofia de Pascal aquilo que chamamos de uma postura antideterminista acerca do homem, pois sua existência não possui relevância em sentido cosmológico, assim como não há princípios absolutos que possam orientá-lo de modo necessário e absoluto na esfera prática. No entanto, a partir de uma reflexão sobre as contradições humanas, presentes no fenômeno do Divertimento (Divertissement), é possível obter uma referência que permita compreender o homem, essa referência é um princípio cristão, o pecado original.
Development of Foot Structure for Humanoid Robot Using Topology Optimization
Authors: Nguyen Van Tinh , Kiuchi Daichi , Hasegawa Hiroshi
Published: August 2018

This paper addresses the development of a foot structure for 22-Degree of Freedom (DoF) humanoid robot. The goal of this research is to reduce the weight of the foot and enable the robot to walk steadily. The proposed foot structure is based on the consideration of cases where the ground reaction forces are set up in different situations. The optimal foot structure is a combination of all the topology optimization results. Additionally, a gait pattern is generated by an approximated optimization method based on Response Surface Model (RSM) and Improved Self-Adaptive Differential Evolution Algorithm (ISADE). The result is validated through dynamic simulation by a commercially available software called Adams (MSC software, USA) with the humanoid robot named KHR-3HV belonging to Kondo Kagaku company.
Prediction of Creep Strain Relaxations in Biomaterials Using Differential Transformation Method
Authors: Adeleye Olurotimi , Eloka Augustine , Sobamowo Gbeminiyi
Published: August 2018

The outcome of most implant failures is tragic. There is an increasing need to reduce the rate of implant failure. While there has been a lot of progress regarding this problem, a lot still needs to be done. The behaviour of biomaterials had been represented using linear models. Linear models failed to capture some certain behaviours in materials due to the nonlinear nature of biomaterials. More work has been done in an attempt to represent the deformation of these biomaterials using non-linear models, which realised success to a degree. However, providing accurate solutions to these models became a problem. Here, An efficient approximate analytical method, differential transformation method (DTM) is provided for prediction of biomaterial deformation. The results of the solutions are found to be in excellent agreements with the results of the numerical methods. It was observed that at high viscosity, the material exhibit very high resistance to deformation and as it decreases, the material allows more deformation, for longer periods of time.Keywords:Biomaterials; Viscoelasticity;deformation;DifferentialTransformation Method;
Silicocarnotite Synthesis and Bioactivity in Artificial Saliva Medium
Authors: Bouregba Adil , Diouri Adeljebbar
Published: August 2018

The aim of this study is the synthesis and investigation of bioactive response of acrystalline silicophosphate.A monophasic silicocarnotite was elaborated by solid state reaction from a mixture of beta-tricaliciumphosphate and dicalcium silicate based on mussel shells according to the diagram of system Ca3(PO4)2–Ca2SiO4, at 65 % and 35% respectively , these starting materials are heated up to 1450 °C to obtain a monophasic silicocaronitite. The obtained result probed that the main crystalline phase which was detected and recognized in the heated sample at 1400 and 1450 °C was a well-crystallized silicocarnotite. The test of bioactivity of silicocarnotite in artificial saliva causes the appearance of a reaction layer on the materials surface after 4 hours soaking and growth up during 30 days.This layer is constituted of a biphasic mixture of Si–Ca–P–H material, silicated hydroxyapatite and hydroxyapatite phase are the mainly developing ones with increasing soaking time.The analysis and characterization of the precipitated appearing on the material surface has confirmed experimentally the in vitro bioactivity of silicocarnotite monophasic material.
Utilization of Lampung Natural Zeolite as Immobilization Media on Biogas Production from Palm Oil Mill Effluent (POME)
Authors: Damayanti Sri Ismiyati , Ginting Simparmin B. , Sofyan Amelia Virgiyani , Putri Alip Tania , Budhijanto Wiratni
Published: August 2018

Lampung is one of provinces with wide area of palm oil plantations and processing industries in Indonesia. Each palm oil mill produces 0.7-1 m3of POME per ton of fresh palm bunches and pollutes the environment when untreated. Furthermore, Lampung is also a region with abundant Natural Zeolites (ZAL) availability. This research was performed to study the influences of modified ZAL as the microorganisms immobilization media (Biocarrier) in biogas production of POME. Hereafter, ZAL as Biocarrier will be applied on Anaerobic Fluidized Bed Reactor (AFBR). AFBR with biocarrier will have higher efficiency than conventional biogas reactor. Furthermore the vertical design of the AFBR does not require excessive land. Modification of ZAL was conducted to provide appropriate place for microorganisms, especially methanogen. This research was started by physical modification of ZAL (CV. Minatama, Lampung), followed by impregnation of ZAL by Fe2+and Mg2+. Each of the modified ZAL was analyzed by XRF, then characterized by XRD and FTIR before used. Based on XRF analysis, SiO2/Al2O3mol ratio of physical activated ZAL was 8.913, while ZAL-Fe2+,and ZAL-Mg2+were 9.957 and 8.8, respectively. The anaerobic process took place in a 2.8 L batch anaerobic digester by adding POME and an active digester effluent of cattle manure as microbial inoculum and 280 grams of each type of the modified ZALs to each digester. Result showed that that impregnated ZAL decreased the organic content of POME more rapidly than the physically treated ZAL. Besides, impregnated zeolite also resulted in higher methane concentration than the digester using physical activated.
How Open Source Software Will Affect Virtual Worlds
Authors: Taney, Jr. Francis X.
Published: August 2018

Essay produced for the Journal of Virtual Worlds Research.
Musings on the State of '3-D Virtual Worlds for Health and Healthcare' in 2009
Authors: Toro-Troconis Maria , Kamel Boulos Maged N.
Published: August 2018

Editors’ CornerMusings on the State of '3-D Virtual Worlds for Health and Healthcare'in 2009by Maria Toro-Troconis, Imperial College London, UK andMaged N Kamel Boulos, University of Plymouth, UK
Overview: State of Virtual Worlds Standards in 2009
Authors: Sivan Yesha Y.
Published: August 2018

This issue is part of an effort to explore the fields of standards for virtual worlds. Working on such standards is both a technical and conceptual. This issue endeavors to enhance, explicate, and analyze various aspects of standards and virtual worlds, and was designed to give a voice to the leading theoretical and practical players within this arena. The issue specifically emphasizes the disciplines of economy and technology as critical harbingers to the endeavor of standards.
Universal Design for Virtual Worlds
Authors: Krueger Alice , Ludwig Ann , Ludwig David
Published: August 2018

We describe three broad approaches to the issue of accessibility design within Virtual Worlds. Our intent is to stimulate the thinking of content designers within Virtual Worlds about these approaches.

Approach 1: Minimal accessibility design principles incorporated into the Virtual World

For much of the current state of Virtual Worlds, this is the default situation: Minimal consideration has been given during design or construction to accessibility issues. This may be the preferred approach when the intent of the designer is artistic creativity.

Approach 2: Emulate Real World accessibility design principles in the Virtual World

In this approach, the designer replicates various aspects of Real World accessibility within the virtual setting. This approach is preferred when the intent is to create learning opportunities about Real World Universal Design or accessibility standards and requirements.

Approach 3: Incorporate only accessibility design principles that are appropriate for the Virtual World

This approach is focused entirely on the virtual environment. The only constraints of importance to the designer are those of the technology itself; Real World accessibility standards are not considered relevant.

We then use these three perspectives to address Virtual World accessibility in landscapes, structures, movement, communication, and perceived environments.

Designers should consider which approach best fits the desired intent and audience of their creation.

We advocate that for most builds, designers incorporate accessibility principles that are appropriate for the Virtual World, and not be constrained to a literal translation of Real World standards and requirements. We conclude that this is a definition of Universal Design for Virtual Worlds.
Topping from the Viewfinder: The Visual Language of Virtual BDSM Photographs in Second Life
Authors: Bardzell Shaowen
Published: August 2018

The paper explores the mutually constituted relations between avatars, space, and artifacts depicted in virtual photographs from Second Life’s BDSM (bondage, discipline, and sadomasochism) communities. Photographs were sampled from thousands of user profiles of Second Life users who explicitly associate themselves with one or more BDSM communities or groups. Using visual analysis and social semiotics, I describe the visual language of these images, and with them, the grammar and symbolism of power and submission, of individual and institution, and of photographer and viewer. The visual language of these photos sheds light on the nature of these communities, including the social and computer-mediated interactions of their participants, and helps explain why virtual BDSM is such a compelling form of play and source of aesthetic innovation for thousands of Second Life residents.
ArchHouseGenerator – A Framework for House Generation
Authors: Rodrigues Nuno , Magalhães Luís , Moura João Paulo , Chalmers Alan , Santos Filipe , Morgado Leonel
Published: August 2018

The manual creation of virtual environments is a demanding and costly task. With the increasing demand for more complex models in different areas, such as the design of virtual worlds, video games and computer animated movies the need to generate them automatically has become more necessary than ever.This paper presents a framework for the automatic generation of houses based on architectural rules. This approach has some innovating features, including the implementation of architectural rules, and produces 2D floor plans as well as complete 3D models, with a high level of detail, in just a few seconds. To evaluate the framework two different applications were developed and the output models were tested for different fields of application (e.g. virtual worlds). The results obtained contain evidences that the proposed framework may lead to the development of several specific applications to produce accurate 3D models of houses representing different realities (e.g. civilizations, epochs, etc.).
Making Sense of the Virtual World for Young Children: Estonian Pre-School Teachers’ Experiences and Perceptions
Authors: Siibak Andra , Vinter Kristi
Published: August 2018

The study provides an overview of teacher perceptions regarding young children’s internet use and media education in pre-schools. Two focus-group interviews with 24 Estonian pre-school teachers were carried out in order to analyze their experiences and opinions about factors that influence pre-school children’s computer and Internet use. Pre-school teachers’ perceptions about their own role in shaping children’s media literacy were also examined. The results indicate that teachers consider the role of the family on children’s computer use to be more significant compared to their own role. Although the teachers started to acknowledge their own role as supervisors and parents’ counselors as the interviews progressed, no curriculum-based media literacy shaping is done in the classrooms. Furthermore, rather than developing children’s awareness of the media, various new media had been used as “enrichment” and significantly fewer activities that would actually help to shape children’s media literacy were mentioned.
Virtual Junk Food Playgrounds in Europe: Advergames in the UK and Hungary
Authors: Flowers Arhlene A. , Lustyik Katalin , Gulyás Emese
Published: August 2018

Unhealthy foods and drinks are among the top products advertised to young children. Considering the growing childhood obesity epidemic and the soaring number of children accessing the Internet, even online junk food advertising has come under increasing scrutiny. Many countries are in the process of expanding and revising existing regulation to account for the realities of the digital age and to respond to health and other social concerns. This paper focuses on two European countries in particular to examine and compare these processes through the lens of junk food advergames aimed at children. Our questions are: 1) Given the differences in the media landscapes of the UK and Hungary, what types of junk food advergames target children?; and 2) In light of the growing childhood obesity problem faced by both nations, how have government bodies, advocacy groups, and advertisers approached junk food advertising targeting children in general and online advertising including advergames in particular? The United Kingdom represents a country with the highest Internet usage by children and the most developed online advertising market in Europe, while Hungary, a post-communist country, represents an emerging media market where young people have less access to the Internet and buying power but constitute a crucial “entry point” for food advertisers.
Growing Up with Neopets: A Personal Case-Study
Authors: Lu Stephanie Louise
Published: August 2018

Neopets.com is a popular virtual pet site attracting roughly 44 million players worldwide. As more and more children spend time on sites like Neopets.com, there is debate over whether they are being victimized or empowered by their exposure to cultural products and discourses online. The existing literature mostly consists of observations and interpretations that are made by researchers from an adult outsider's perspective. In this study, I discuss how, in my nine years of membership on Neopets.com, I have developed an awareness of myself in relation to a larger society, and also gained important skills that proved useful to me later in life. I conclude that a virtual world can enable a young person to try on active roles in addition to passive ones in a modern commercial society.
Virtual worlds as a site of convergence for children’s play
Authors: Lim Sun Sun , Clark Lynn Schofield
Published: August 2018

Virtual worlds have made notable inroads into the lives of children, affording online extensions of their offline lives In this article, we propose a conceptual framework for understanding the space that virtual worlds occupy in children’s play and the ways in which children’s participation in them overlap with their everyday play experiences, both offline and mediated. We argue that virtual worlds can be viewed as sites of convergence for children’s play in that virtual worlds allow for almost all aspects of children’s play to converge, primarily manifested in the convergence of social spheres, the convergence of play spaces and playthings, the convergence of cultures and the convergence of learning experiences. we explain how such convergence, while presenting valuable opportunities for children to learn and develop, will not be fully exploited without a corresponding ability on the part of parents and children to recognise potential risks; and for parents and educators to scaffold these learning opportunities.
‘Othering’ and ‘Self-othering’ in the Book of Tobit: A Jungian approach
Authors: Efthimiadis-Keith Helen
Published: August 2018

The Book of Tobit is replete with various instances of ‘othering’ that hold the potential for alienation and a variety of strong emotions. For example, Tobit ‘others’ Anna by insisting that she had stolen a goat, whereas she had not. Following a Jungian paradigm, this paper reads the various ‘otherings’ inherent in the interrelationships between the characters as reflections of the main character’s relationship with himself. In so doing, it analyses these relationships through Jung’s concepts of Eros/Logos and anima/animus to determine the nature of Tobit’s ‘self-othering’ and its effect on those around him. It is concluded, among others, that Tobit’s multiple ‘self-otherings’ and his ‘othering’ of ‘other’ characters are because of his suppression of his anima-Eros function that has, in turn, given rise to a dominant (and demonic) animus-Logos.
Systematic Theology – An experiential approach: Core assumptions of my ‘Invitation to Systematic Theology’
Authors: Nürnberger Klaus
Published: August 2018

Nürnberger’s ‘Faith in Christ Today: Invitation to Systematic Theology’ is meant to serve the proclamation of the Word of God in modern times. Based on ‘experiential realism’, as used by science, it restricts itself to immanent reality, avoids the reification of idealised abstractions and biblical metaphors and follows an emergent-evolutionary hermeneutic. God’s self-disclosure manifests itself as (1) creative power in the cosmic process as explored by science, (2) benevolent intentionality as proclaimed on the basis of the Christ-event and (3) a motivating and transforming vision in the community of believers. Classical doctrines are reconceptualised in action terms, rather than ontological terms. Christology: The ministry, death and elevation of Jesus of Nazareth as God’s messianic representative manifest God’s redemptive intentionality. Trinity: The God manifest in Christ is identical with the God of Israel and the Creator of the universe and the divine Spirit transforming and empowering the community of believers. Eschatology: The thrust of God’s vision of comprehensive optimal well-being moves through time like a horizon opening up ever new vistas, challenges and opportunities.Intradisciplinary and/or interdisciplinary implications: The task of Systematic Theology is to offer as comprehensive and consistent a presentation of the Christian faith as possible under current circumstances. This involves the retrieval of the biblical message from its ancient conceptualisations and to repackage it in current world view assumptions. To reach a readership informed by modern science, technology, commerce and the consumer culture, Nürnberger’s Systematic Theology applies the approach of experiential realism as practised by the positive sciences: restricting its analyses to immanent reality and avoiding metaphysical constructs. It follows a consistent emergent-evolutionary hermeneutic and works on an interdisciplinary basis, using insights from modern physics, biology, neurology and sociology. God is conceptualised as the transcendent Source and Destiny of experienced reality. The core of the Christian message is God’s suffering, transforming acceptance of the unacceptable, which involves us in its dynamics. It is geared to transformation rather than perfection. It is applied to all aspects of reality, including, for example, entropy, death and natural evil and so on. In this way, the author hopes to help Christians to regain their intellectual integrity and the credibility of their message.
Квадраты Дэрфи в композициях
Authors: Archibald Margaret , Blecher Aubrey , Brennan Charlotte , Knopfmacher Arnold , Mansour Toufik
Published: August 2018

Рассматриваются композиции (упорядоченные разбиения) числа $n$. В частности, основное внимание уделяется представлению композиций в виде столбчатых диаграмм, которые содержат или не содержат квадраты размера $s \times s$. Квадрат Дэрфи (изучавшийся в теории разбиений) мы определяем как наибольший «лежачий» квадрат, основание которого лежит на основании диаграммы. С помощью производящих функций и асимптотического анализа анализируются разбиения $n$, для которых размеры квадратов Дэрфи не превосходят $s \times s$. Рассматриваются общие и средние количества лежачих квадратов размера $s\times s$ в диаграммах, соответствующих разбиениям числа $n$.
Effect of Low-Frequency Vibration on Human Body in Standing Position Exposed to Railway Vehicle
Authors: Govindan Rajesh , Prakash Harsha Suraj
Published: August 2018

In this paper, the dynamic characteristics of the human body were investigated by developing a 3-D finite element model based on 50th percentile anthropometric data for a 54 kg Indian male subject in standing position by considering human body segments as an ellipsoid. The finite element modal analysis is carried out to extract several low-frequency vibration modes and its vibration mode shapes were presented in this paper. The results show that the lowest natural frequency of the standing passenger model occurs in the fore-and-aft direction. The second natural frequency occurs in the lateral direction and the first order natural frequency of the standing passenger model in the vertical direction occurs at 5.379 Hz. The model will be helpful to predict the vibration response of human body under various vibration environment encounters in the railway vehicle.
Obesidade
Authors: Kawai Natasha Mike , Coelho Vitória Maria Leal , Garcia Hamilton Cezar Rocha
Published: August 2018

Objetivo: Realizar revisão sistemática de artigos que abordem sobre obesidade, técnicas cirúrgicas e indicações, publicados em língua inglesa e portuguesa. Método: Os artigos foram selecionados de acordo com o período de publicação de janeiro de 2013 a abril de 2018. Os descritores utilizados foram “obesidade”, “cirurgia bariátrica”, “técnicas cirúrgicas para obesidade”, “grampeamento gástrico”. As bases de dados utilizadas foram PUBMED, SCIELO, BVS e Biblioteca COCHRANE. Resultados: Foram encontrados 12 artigos que abordam as técnicas cirúrgicas mais utilizadas, atualmente, nos casos de obesidade e 4 artigos sobre as indicações para cada técnica cirúrgica empregada. Conclusão: Nos 16 artigos pesquisados, buscou-se a descrição e indicações das principais técnicas cirúrgicas utilizadas atualmente em pacientes obesos.
H. pylori
Authors: Sousa Thiago Celeira de , Almeida Ursula Tatiane de Farias Hounsell , Bastos Dauana Arruda de Oliveira
Published: August 2018

Objetivo: Realizar uma revisão sobre os tratamentos e a resistência do H. pylori. Método: A pesquisa foi desenvolvida no período de Fevereiro a Junho de 2018, e realizada a partir das bases de dados: Medline, SciELO, LILACS, PubMed, e Bireme por meio dos descritores: Helicobacter Pylori, Resistência Antimicrobiana, Prevalência e Câncer Gástrico. Resultados: A busca por literatura produziu um total de 85 artigos que foram submetidos a avaliação por dois avaliadores independentes. Destes, 20 atenderam critérios de inclusão previamente estabelecidos. Conclusão: A totalidade dos estudos envolvidos nesta pesquisa nos mostram uma elevada prevalência da infecção por H. pylori e alta taxa de resistência para muitos antibióticos, tendo isto um impacto preocupante em um continente com áreas de alta prevalência de contaminação e também com altas taxas de incidência de doenças graves relacionadas a infecção, como lesões pré-neoplásicas e o adenocarcinoma gástrico. As taxas de resistência á claritomicina variaram entre 11,1% a 47% nos resultados dos artigos selecionados para este estudo, sendo portando o antimicrobiano que apresentou a maior taxa de resistência. Em relação ao tratamento, os 3 principais guidelines utilizados (Colégio Americano, Consenso Brasileiro e Consenso Europeu) concordam em relação á primeira linha de tratamento, porém os consensos Europeu e Americano propõem o uso de metronidazol como alternativa á amoxicilina nesta linha de tratamento.
Correlação entre o equilíbrio funcional e o estadiamento da Doença de Parkinson
Authors: Pereira Marina Teixeira , Oliveira Daniella Meneses Seawright , Dias Ana Carolina Alves Maués , Moraes Ananda Maria Figueiró de , Dias George Alberto Silva , Oliveira Ediléa Monteiro de
Published: August 2018

Objetivo: Determinar se há correlação entre o equilíbrio funcional e o estágio da doença de Parkinson. Método: Foram selecionados 13 pacientes diagnosticados com doença de Parkinson que tiveram a severidade da patologia classificada de acordo com a Escala de Hoehn e Yahr (modificada), utilizada como critério de seleção e avaliação. Em sequência, por meio de questionário, foram coletadas informações pessoais e clínicas. Posteriormente aplicou-se o teste de Tinetti e o teste Timed Up and Go para definição das condições de equilíbrio e marcha. Para a análise das variáveis categóricas utilizaram-se os testes G (Aderência) e o teste de correlação de Spearman (p≤0,05). Resultados: No teste de Tinetti determinou-se a presença de 6 pacientes (46,2%) com alto risco de queda. Já o TUG apontou que 6 pacientes (46,2%) apresentaram alto grau de comprometimento funcional. A Escala de Hoehn e Yahr (modificada) classificou os indivíduos em estágios de leve a moderado. As correlações entre os testes (r = -0,8; p = 0,0004) e entre o Timed Up and Go e Escala de Hoehn e Yahr (modificada) (r = 0,8; p = 0,0001) e o teste de Tinetti e mesma escala (r = -0,8; p = 0,0006) demonstraram correlação forte e significância estatística. Conclusão: Os instrumentos avaliativos do equilíbrio funcional utilizados apresentam correlação com a Escala de Hoehn e Yahr (modificada), auxiliando a determinar a severidade da doença de Parkinson.
Responses of developmental and physiological traits to manipulated incubation conditions in broiler embryos at hypoxic high altitude
Authors: Babacanoğlu Elif
Published: August 2018

Abstract. The effects of hypoxia at
increased altitude levels on the cardio-respiratory development of broiler
embryos are distinct in comparison with those at sea level. The aim of the
study was to investigate the effects of high incubation temperature (H) and
oxygen supplementation (O) during hypoxic high altitude (HA) on developmental
and physiological traits of embryos and hatching performance of embryonated
hatching eggs in broilers at different embryonic stages. A total of 1280 eggs
obtained from broiler breeders laid at sea level were used. Eggshell quality
characteristics were measured for 20 eggs. The rest of the 1260 eggs were
divided into seven incubation condition (IC) groups (180 eggs per group)
including a control group at 37.8 ∘C and 21 % O2; O
groups, with daily 1 h 23.5 % O2 supplementation at
37.8 ∘C as O0−11, O12−21, and O18−21; H groups
at 38.5 ∘C high incubation temperature at 21 % O2 as
H0−11, H12−21, and H18−21 from days 0 to 11, 12 to 21, and 18 to 21 of incubation,
respectively. All groups were incubated in three different incubators at
hypoxic HA. The effect of IC was determined on eggshell temperature, hatching
performance, embryo development, right ventricular (RV) to total ventricular
(TV) ratio, and blood parameters. The highest egg water loss and embryonic
mortality and the lowest hatchability were in the H0−11 group, which
depended on increased eggshell temperature during incubation. On day 18 of
incubation, due to the decreased egg water loss in the O12−21 and
O18−21 groups, there was an increase in hatchability in fertile eggs
similar to the middle and late H groups. Towards the end of incubation,
embryo/chick weights were not different and RV and TV weights increased in
the treated groups, and the RV ∕ TV ratio changed between 15 and
26 %. At hatching, yolk
sac weight increased in H0−11 and H12−21 groups. The O groups
had the lowest serum tri-iodothyronine (T3) concentration as distinct
from H groups. The serum thyroxine (T4) concentration increased in the
treated groups, dependent on sex of the embryo. Blood hemoglobin
concentration of O groups decreased relative to other groups. The hematocrit
value was the lowest in the O12−21 and highest in the H12−21
groups. The H and O treatments during pre-hatch hypoxic HA condition can be
positively evaluated on physiological traits of embryos after half of
incubation depended on the timing of the IC exposure to the hatching eggs
obtained from broiler breeders at sea level.
Retrieval of desert dust and carbonaceous aerosol emissions over Africa from POLDER/PARASOL products generated by the GRASP algorithm
Authors: Chen Cheng , Dubovik Oleg , Henze Daven K. , Lapyonak Tatyana , Chin Mian , Ducos Fabrice , Litvinov Pavel , Huang Xin , Li Lei
Published: August 2018

Abstract. Understanding the role atmospheric aerosols play in the Earth–atmosphere
system is limited by uncertainties in the knowledge of their distribution,
composition and sources. In this paper, we use the GEOS-Chem based inverse
modelling framework for retrieving desert dust (DD), black carbon (BC) and
organic carbon (OC) aerosol emissions simultaneously. Aerosol optical depth (AOD) and aerosol absorption optical depth (AAOD) retrieved from the
multi-angular and polarimetric POLDER/PARASOL measurements generated by the
GRASP algorithm (hereafter PARASOL/GRASP) have been assimilated. First, the
inversion framework is validated in a series of numerical tests conducted
with synthetic PARASOL-like data. These tests show that the framework allows
for retrieval of the distribution and strength of aerosol emissions. The
uncertainty of retrieved daily emissions in error free conditions is below
25.8 % for DD, 5.9 % for BC and 26.9 % for OC. In addition, the BC
emission retrieval is sensitive to BC refractive index, which could produce
an additional factor of 1.8 differences for total BC emissions. The approach
is then applied to 1 year (December 2007 to November 2008) of data over the
African and Arabian Peninsula region using PARASOL/GRASP spectral AOD and
AAOD at six wavelengths (443, 490, 565, 670, 865 and 1020 nm). Analysis of
the resulting retrieved emissions indicates 1.8 times overestimation of the
prior DD online mobilization and entrainment model. For total BC and OC, the
retrieved emissions show a significant increase of 209.9 %–271.8 % in comparison to the prior carbonaceous aerosol emissions. The
model posterior simulation with retrieved emissions shows good agreement with both
the AOD and AAOD PARASOL/GRASP products used in the inversion. The
fidelity of the results is evaluated by comparison of posterior simulations
with measurements from AERONET that are completely independent measurements
and more temporally frequent than PARASOL observations. To further test the
robustness of our posterior emissions constrained using PARASOL/GRASP, the
posterior emissions are implemented in the GEOS-5/GOCART model and the
consistency of simulated AOD and AAOD with other independent measurements
(MODIS and OMI) demonstrates promise in applying this database for modelling
studies.
The diverse chemical mixing state of aerosol particles in the southeastern United States
Authors: Bondy Amy L. , Bonanno Daniel , Moffet Ryan C. , Wang Bingbing , Laskin Alexander , Ault Andrew P.
Published: August 2018

Abstract. Aerosols in the atmosphere are chemically complex with thousands of chemical
species distributed in different proportions across individual particles in
an aerosol population. An internal mixing assumption, with species present in
the same proportions across all aerosols, is used in many models and
calculations of secondary organic aerosol (SOA) formation, cloud activation,
and aerosol optical properties. However, many of these effects depend on the
distribution of species within individual particles, and important
information can be lost when internal mixtures are assumed. Herein, we show
that – as found during the Southern Oxidant and Aerosol Study (SOAS) in
Centreville, Alabama, at a rural, forested location – aerosols frequently
are not purely internally mixed, even in the accumulation mode
(0.2–1.0 µm). A range of aerosol sources and the mixing state were
determined using computer-controlled scanning electron microscopy with
energy-dispersive X-ray spectroscopy (CCSEM-EDX) and scanning transmission
X-ray microscopy–near-edge X-ray absorption fine structure spectroscopy
(STXM-NEXAFS). Particles that were dominated by SOA and inorganic salts
(e.g., ammonium sulfate) were the majority of particles by number fraction
from 0.2 to 5 µm with an average of 78 % SOA in the
accumulation mode. However, during certain periods contributions by sea spray
aerosol (SSA) and mineral dust were significant to accumulation (22 % SSA
and 26 % dust) and coarse-mode number concentrations (38 % SSA and
63 % dust). The fraction of particles containing key elements (Na, Mg, K,
Ca, and Fe) were determined as a function of size for specific classes of
particles. Within internally mixed SOA/sulfate particles < 5 %
contained Na, Mg, K, Ca, or Fe, though these nonvolatile cations were present
in particles from the other sources (e.g., SSA and dust). Mass estimates of
the aerosol elemental components were used to determine the extent of
internal versus external mixing by calculating the mixing state index (χ). The aerosol population was more externally mixed than internally mixed
during all time periods analyzed. Accumulation mode aerosol ranged from more
internally mixed during SOA periods to mostly externally mixed during dust
periods. Supermicron aerosols were most externally mixed during SOA time
periods, when more SOA particles added a distinct supermicron class, and more
internally mixed when dominated by a single particle type (e.g., SSA or
dust). These results emphasize that neither external nor internal mixtures
fully represent the mixing state of atmospheric aerosols, even in a rural,
forested environment, which has important implications for air quality and
climate modeling.
A new roughness parameterization accounting for wind-wave (mis)alignment
Authors: Porchetta Sara , Temel Orkun , Muñoz-Esparza Domingo , Reuder Joachim , Monbaliu Jaak , van Beeck Jeroen , van Lipzig Nicole
Published: August 2018

Abstract. Two-way feedback occurs between offshore wind and waves. However, the influence of the waves on the wind profile remains remains understudied, in particular the momentum transfer between the sea surface and the atmosphere. Previous studies showed that for swell waves it is possible to have increasing wind speeds in case of aligned wind-wave directions. However, the opposite is valid for opposed wind-wave directions, where a decrease in wind velocity is observed. Up to now, this behavior has not been included in most numerical models due to the lack of an appropriate parameterization of the resulting effective roughness length. Using an extensive data set of offshore measurements in the North Sea and the Atlantic Ocean, we show that the wave roughness affecting the wind is indeed dependent on the alignment between the wind and wave direction. Moreover, we propose a new roughness parameterization taking into account the dependence on alignment, consisting of an enhanced roughness for increasing misalignment. Using this new roughness parameterization in numerical models will facilitate a better representation of offshore wind, which is relevant to many applications including offshore wind energy and climate modeling.
Core and margin in warm convective clouds. Part I: core types and evolution during a cloud's lifetime
Authors: Heiblum Reuven H. , Pinto Lital , Altaratz Orit , Dagan Guy , Koren Ilan
Published: August 2018

Abstract. The properties of a warm convective cloud are determined by the competition between the growth and dissipation processes occurring within it. One way to observe and follow this competition is by partitioning the cloud to core and margin regions. Here we look at three core definitions: positive vertical velocity (Wcore), supersaturation (RHcore), and positive buoyancy (Bcore), and follow their evolution throughout the lifetime of warm convective clouds. We show that the different core types tend to be proper subsets of one another in the following order: Bcore ⊆ RHcore ⊆ Wcore. Using single cloud and cloud field simulations, we find that this property is generally maintained during the growing and mature stages of a cloud's lifetime, but can break down during the dissipation stage. The cloud and its cores are centered at a similar location, while during dissipation the cores may reside at the cloud periphery. A theoretical model is developed, showing that in both the adiabatic and non-adiabatic cases, Bcore can be expected to be the smallest core, due to two main reasons: (i) entrainment rapidly decreases the buoyancy core compared to the other core types, and (ii) convective clouds may exist while being completely negatively buoyant (while maintaining positive vertical velocity and supersaturation).
Core and margin in warm convective clouds. Part II: aerosol effects on core properties
Authors: Heiblum Reuven H. , Pinto Lital , Altaratz Orit , Dagan Guy , Koren Ilan
Published: August 2018

Abstract. The effects of aerosol on warm convective cloud cores are evaluated using single cloud and cloud field simulations. As presented in Part I, the Bcore ⊆ RHcore ⊆ Wcore property is seen during growth of warm convective clouds. We show that this property is kept irrespective of aerosol concentration. During dissipation core fractions generally decrease with less overlap between cores. However, for clouds that develop in low aerosol concentrations capable of producing precipitation, Bcore and subsequently Wcore volume fractions may increase during dissipation (i.e. loss of cloud mass). The RHcore volume fraction decreases during cloud lifetime and shows minor sensitivity to aerosol concentration. It is shown that a Bcore forms due to two processes: (i) Convection – condensation within supersaturated updrafts and release of latent heat, (ii) Adiabatic heating due to weak downdrafts. The former process occurs during cloud growth for all aerosol concentrations. The latter process only occurs for low aerosol concentrations during dissipation and precipitation stages where large mean drop sizes permit slow evaporation rates. The aerosol effect on the diffusion efficiencies play a crucial role in the development of the cloud and its partition to core and margin. Using the RHcore definition, it is shown that the total cloud mass is mostly dictated by core processes, while the total cloud volume is mostly dictated by margin processes. Increase in aerosol concentration increases the core (mass and volume) due to enhanced condensation but also decreases the margin due to evaporation. In clean clouds larger droplets evaporate much slower, enabling preservation of cloud volume and even increase by dilution (detrainment while losing mass). This explains how despite having smaller cores and less mass, cleaner clouds may live longer and grow to larger sizes.
Hydroclimatic variations in southeastern China during the 4.2 ka event reflected by stalagmite records
Authors: Zhang Haiwei , Cheng Hai , Cai Yanjun , Spötl Christoph , Kathayat Gayatri , Sinha Ashish , Edwards R. Lawrence , Tan Liangcheng
Published: August 2018

Abstract. The collapses of several Neolithic cultures in China are considered to have been associated with abrupt climate change during the 4.2 ka event (4.2–3.9 ka BP). The hydroclimate of this event in the monsoonal region of China, however, is still poorly known, except for a few published stalagmite records from the lower reaches of Yangtze River. In this study, a high-resolution record of monsoon precipitation between 5.3 and 3.6 ka BP based on a stalagmite from Shennong cave, Jiangxi Province, southeast China, is presented. Coherent variations in δ18O and δ13C reveal that the climate in this part of China was dominantly wet between 5.3 and 4.5 ka BP and mostly dry between 4.5 and 3.6 ka BP, interrupted by a wet interval (4.3–4.05 ka BP). A comparison with other records from monsoonal China suggests that monsoon precipitation decreased in northern China but increased in southern China during the 4.2 ka event. We propose that the weakened East Asian summer monsoon controlled by the reduced Atlantic Meridional Overturning Circulation resulted in this contrasting distribution of monsoon precipitation between north and south China. During the 4.2 ka event the rain belt remained longer at its southern position, giving rise to a pronounced humidity gradient between northern and southern China.
The point of no return for climate action: effects of climate uncertainty and risk tolerance
Authors: Aengenheyster Matthias , Feng Qing Yi , van der Ploeg Frederick , Dijkstra Henk A.
Published: August 2018

Abstract. If
the Paris Agreement targets are to be met, there may be very few years left
for policy makers to start cutting emissions. Here we calculate by what year,
at the latest, one has to take action to keep global warming below the 2 K
target (relative to
pre-industrial levels) at the year 2100 with a 67 % probability; we call
this the point of no return (PNR). Using a novel, stochastic model of
CO2 concentration and global mean surface temperature derived from
the CMIP5 ensemble simulations, we find that cumulative CO2 emissions
from 2015 onwards may not exceed 424 GtC and that the PNR is 2035 for the
policy scenario where the share of renewable energy rises by
2 % year−1. Pushing this increase to 5 % year−1 delays the
PNR until 2045. For the 1.5 K target, the carbon budget is only 198 GtC
and there is no time left before starting to increase the renewable share by
2 % year−1. If the risk tolerance is tightened to 5 %, the PNR is
brought forward to 2022 for the 2 K target and has been passed already for
the
1.5 K target. Including substantial negative emissions towards the end of the century
delays the PNR from 2035 to 2042 for the 2 K target and to 2026 for the 1.5 K
target. We thus show how the PNR is impacted not only by the
temperature target and the speed by which emissions are cut but also by risk
tolerance, climate uncertainties and the potential for negative emissions.
Sensitivity studies show that the PNR is robust with uncertainties of at most
a few years.
Reconstructing lateral migration rates in meandering systems – a novel Bayesian approach combining optically stimulated luminescence (OSL) dating and historical maps
Authors: Quik Cindy , Wallinga Jakob
Published: August 2018

Abstract. Identifying lateral migration rates of meandering rivers is
relevant both for fluvial geomorphology and to support river management.
Lateral migration rates for contemporary meandering systems are often
reconstructed based on sequential remote-sensing images or historical maps;
however, the time frame for which these sources are available is limited and
hence likely to represent fluvial systems subjected to human influence. Here,
we propose to use scroll bar sequences as an archive to look further back in
time using optically stimulated luminescence (OSL) dating of sand-sized
quartz grains. We develop a modelling procedure for the joint Bayesian
analysis of (OSL) dating results and historical map data. The procedure is
applied to two meanders from the Overijsselse Vecht, a medium-sized sand-bed
river in the Netherlands. We obtained nine samples for OSL dating from scroll
bars and combined OSL dating results with historical map data for the period
1720–1901 CE (Common Era). The procedure we propose here incorporates the
strengths of both data types for reconstructing fluvial morphodynamics over
longer time frames. Using an iterative modelling approach, we translate
spatial uncertainty of historical maps into temporal uncertainty of channel
position required for Bayesian deposition modelling. Our results indicate
that meander formation in the Overijsselse Vecht system started around 1400
CE, and lateral migration rates were on average 2.6 and
0.9 m yr−1 for the two investigated
bends, until river channelization around 1900 CE.