bluuebunny/crossref_metadata_2025 huggingface dataset:
Les enjeux du renouvellement du parc nucléaire
Authors: Faudon Valérie
Published: January 2020

Entre 2030 et 2050, la France devra renouveler une partie de son parc nucléaire actuel par de nouveaux moyens de production, dont des moyens nucléaires de nouvelle génération. Ce renouvellement recouvre plusieurs enjeux : des enjeux énergétiques : compte tenu du calendrier historique extrêmement rapide de la construction des tranches dans les années 1980, la France peut être confrontée à un effet falaise dans la décennie 2040 ; des enjeux économiques : des leviers existent pour réduire les coûts du nouveau nucléaire dans le cadre d’un programme optimisé, où la compétitivité doit être évaluée au regard des services rendus au système électrique ; des enjeux industriels : les compétences nécessaires pour la construction du nouveau nucléaire sont spécifiques. Reconstituées en partie dans le cadre de la construction de l’EPR Flamanville, elles sont aujourd’hui fragiles et risquent d’être perdues à nouveau si la filière, qui a du mal à recruter aujourd’hui, ne dispose pas rapidement d’une visibilité sur les chantiers à venir.
Evaluation of a Wellness Clinic in Assessing Knowledge Synthesis Among Bachelor of Science in Nursing Students
Authors: Christensen Stacy , Desrochers Raymond , Langevin Kerri , Espelin Jill
Published: January 2020

Background:

To enrich students' clinical learning experience and facilitate their ability to meet the baccalaureate outcomes, students rotate through a faculty-developed nursing wellness clinic. This unique setting was thought to promote knowledge synthesis of the Bachelor of Science in Nursing (BSN) curriculum, yet it had not been formally evaluated.

Method:

A qualitative study was designed to examine the experiences of senior BSN students who rotated through the wellness clinic setting. Focus groups were held for students who volunteered to participate.

Results:

Analysis identified three themes: Competence and Confidence Issues, Rewards and Frustrations of Delivering Care in the Community, and Using What We Know.

Conclusion:

Findings indicate that nursing wellness clinics can provide a rich learning experience and enable students to synthesize the BSN and liberal arts curriculum in order to deliver care. The study is limited due to the small sample size. Future research on the effectiveness of this clinical placement is warranted.

[
J Nurs Educ
. 2020; 59(1):26–29.]
Jean Cocteau, Pablo Picasso, Léonide Massine et Erik Satie : Parade, 1917, et les avant-gardes
Authors: Laliberté Martin
Published: January 2020

Les technologies des différentes révolutions industrielles ont radicalement transformé le monde quotidien et la sensibilité occidentale ; elles ont permis de profonds renouvellements après une période d’usure. À un moment de rupture particulièrement forte, celui de la seconde révolution industrielle, Cocteau, Satie, Picasso, Massine se sont réunis pour former une constellation artistique le temps d’un spectacle remarquable : Parade (1917). Plus spécifiquement, cet article aborde Parade comme un cas particulièrement riche de mutation des sensibilités et de convergence des différentes tendances artistiques et culturelles de fond qui a permis l’émergence esthétique du bruit.
Le Turin du jeune Gramsci
Authors: Belviso Francesca
Published: January 2020

Cet article propose une réflexion autour du concept de modernité tel qu’il est forgé et divulgué dans l’entre-deux-guerres par certains des plus importants chefs de file de l’intelligentsia et de l’art avant-gardiste italien tels que Filippo Tommaso Marinetti, Antonio Gramsci, ainsi que le jeune écrivain Cesare Pavese. Sous la plume de ces intellectuels et artistes qui ont durablement marqué l’histoire culturelle italienne de la première moitié du Novecento, la ville de Turin devient un véritable creuset de nouveauté, mais également un laboratoire d’expérimentations politiques et artistiques où l’image idéale de la « ville du futur » va constituer un modèle pour l’Italie tout entière.
Challenges and Implications of Mobility as a Service (MaaS)
Authors: Gonçalves Luísa , Silva João Pedro , Baltazar Sara , Barreto Luís , Amaral António
Published: January 2020

This introductory chapter provides a synopsis of the underlying factors that enable the existence of the mobility as a service (MaaS) concept and its role regarding the improvement of the performance of transportation systems. Therefore, several considerations are made to contextualize MaaS in modern societies explaining not only its main functions and advantages but also the challenges facing its widespread implementation.
Sustainable Mobility in Smart Cities
Authors: Marconi Annapaola , Loria Enrica
Published: January 2020

MaaS, with its user-centric vision aiming at more flexible, personalized, and on-demand mobility services, has a perspective to address the key sustainability challenges of the mobility of the future: transport solutions that are integrated, inclusive, and time-efficient, while containing the economic, social, and environmental costs. Civic engagement is a key success factor towards this objective: to fully embrace MaaS transformation, citizens need to feel part of the process. Gamification proved to be effective to raise citizens' awareness, encourage their participation, and promote a gradual but profound behavior change. These characteristics can be exploited by MaaS solutions to attract users and encourage the acceptance of tailored mobility plans. The chapter presents two successful cases of gamified systems aiming at promoting a more sustainable mobility, Play&Go and Kids Go Green; investigates the potential of gamified systems, in combination with MaaS solutions, in terms of citizens' engagement and behavior change; and discusses current limitations and future challenges.
Proposing a Diversity Intelligence Training Framework for Leaders and Managers to Attract, Maintain, and Balance Mature Workers
Authors: Lawson Sheron , Hughes Claretha
Published: January 2020

The workforce is becoming more diverse with the increasing number of mature workers delaying retirement and working beyond the legal retirement age. Retaining mature workers in organizations can be challenging. Training leaders and managers in diversity intelligence (DQ) has the potential to lead to better and more effective supervision of diverse employees. Competent and skilled managers and leaders who are trained in DQ will be more able to help in the attracting, retaining, and balancing mature workers. The chapter proposes using the three learning processes of enactive, iconic, and symbolic from Bruner's discovery learning theory to teach leaders and managers DQ. The learning outcome is that managers will become mentors and coaches who are equipped to use goal-oriented and transformative processes to supervise the independent, motivated, and proactive adult workers.
The Social Media Imperative
Authors: Camargo Elsa
Published: January 2020

As the usage of social media among faculty increases, it has become pressing for institutions to find ways to monitor and support this activity. In some cases, academic administrators have responded by reprimanding faculty members through suspension and forced leaves of absence. This chapter focuses on the role social media play in the careers of faculty, the function a mature workforce (senior faculty and administrators) has in adequately supporting junior faculty's use of social media, and on how institutions equip mature senior faculty and administrators (MSFAs) with the necessary skills to manage junior faculty's use of social media for the purpose of balancing a mature workforce in academia.
Numerical Study on Axial Crushing of Auxetic Foam-Filled Square Tube
Authors: Mohsenizadeh Saeid , Ahmad Zaini , Alias Amran
Published: January 2020

Filling the thin-walled tubes with a foam core is a typical method to enhance the energy absorption performance and stabilize their crushing responses under impact loading. Recently, auxetic foam material with negative Poisson’s ratio has gained remarkable popularity as an effective candidate to enhance the energy absorption capability of structures. In this paper, polyurethane auxetic foam is suggested as a foam core with the negative Poisson’s ratio of-0.31. Numerical simulation was performed to quantify the crush characteristics of auxetic foam-filled square aluminum tubes for variations in initial width of tube under quasi-static axial loading using the nonlinear finite element (FE) code LS-Dyna. Based on the numerical results, the influence of tube width was quantified in terms of energy absorption (EA), specific energy absorption (SEA), initial peak force (Pmax) and crush force efficiency (CFE). It is found that the progressive collapse and deformation modes of auxetic foam-filled tube (AFFT) is pronouncedly affected by varying the tube width. Furthermore, the SEA of AFFT is remarkably sensitive to the tube width variations, yet show low sensitivity to the EA of AFFT. The present study provides new design information on the crush response and energy absorption performance of auxetic foam-filled square tube with varying tube width.
Effect of Heat Treatment Process on the Hardness of Aluminium356/Silicon Carbide Particulate Composites
Authors: Salyajivin Satawat , Talangkun Sukangkana
Published: January 2020

This research is aimed to study effect of holding time and temperature in solution treatment and ageing on the hardness of the Aluminum A356 reinforced with silicon carbide particles. Alumimium matrix coposite was particulated with 15 microns-SiC with the content of 15 percent by weight. A356/SiC composites was prepared by the stirr casting. The stirrer was continuously stired at a speed of 300 rpm during acooling temperature to semi-solid state of 610 °C. During stirring the SiC powder was slowly added into the melt and continuously stirred for another 10 min. Then poured into the mold at the pouring temperature of 680°C. A356/SiC composites then subjected to a solid solution treatment with temperature of 540 °C for 1 hr. quenched with water and age hardening temperature of 120 and 135 °C for 3, 6, 12 and 18 hr. The result showed that, in as cast conditions, the composite with 15 microns silicon carbide, the 15 wt%SiC specimen exhibited the average hardness of 64.33 HB. After solution treated, the hardness of samples decreased. the specimen exhibited the average hardness of 53.83 HB. After ageing, the hardness of samples increased. the specimen ageing 120 °C 6 hr. exhibited the lowest average hardness of 51.45 HB while the specimen ageing 135 °C 18 hr. exhibited the highest average hardness of 73.54 HB.
Adapting ANFIS to Improve Field Rebound Hammer Test for Concrete Compressive Strength Estimation
Authors: Wang Yu Ren , Chiang Dai Lun , Chen Yi Jao
Published: January 2020

Rebound hammer tests are one of the most popular non-destructive testing methods to examine the concrete compressive strength in the field. Rebound hammer tests are relatively easy to conduct and low cost. More importantly, it will not cause damage to the existing structure and can obtain the results in a short time. However, concrete compressive strength estimations provided by rebound hammer tests have an average of around 20% mean absolute percentage error (MAPE) when comparing to the results from destructive tests. This research proposes an alternative approach to estimate the concrete compressive strengths using the rebound hammer test data. The alternative approach is to adopt the Artificial Neural Fuzzy Inference Systems, ANFIS, to develop an AI-based prediction model for the rebound hammer tests. A total of 100 rebound hammer tests are conducted in a 24-story residential building. Core samples are carefully taken to obtain the actual compressive tests. The data collected are used to train and validate the ANFIS prediction model. The results show that the proposed ANFIS model has successfully reduced the MAPE to 10.01%.
A Characteristic and a Precisely Constitutive Model for Undrained Clay
Authors: Hsu Shih Tsung , Hu Wen Chi , Lin Yu Heng , Ling Zhuo
Published: January 2020

Constitutive models for soils are usually adopted in numerical method to analyze the behavior of geotechnical structures. This study performs a series of consolidated-undrained triaxial tests to establish the stress-strain curve of clay. A constitutive model that considers continuous strain hardening-softening is proposed based on the results of triaxial tests. Triaxial test results reveal that undrained shear strength linearly increases with an increase in consolidated pressure , the normalized undrained shear strength is about 0.52 not only for this study but also for the other two cases around Taipei Basin. Due to undrained condition, an associated flow rule between plastic strain increment and stress tensor is adopted. As accumulative plastic strain or/and consolidated pressure change, the mobilized undrained shear strength also changes. All parameters needed for the proposed model can be expressed as a function of undrained shear strength Su, The mobilized undrained shear strength for the proposed model during strain hardening-softening can be in term of accumulative plastic strain. This model can calculate the stress-strain curves of clayed soils accurately.
Size Effect of Drill Bit on Coupled Vibrations during High Speed Micro-Drilling Process of Composite Printed Circuit Board
Authors: Dat Hoang Tien , Nguyen Van Du , Nguyen Hai Anh , Nguyen Ngoc Kien , Yen Hoang Thi Hai , Nguyen Danh Tuyen
Published: January 2020

This paper presents a comprehensive method to consider the size effect of the drill bit on the lateral and torsional vibrations of micro-drill tool accurately. Based on the Euler angles, and Lagrange’s equation, the dynamic micro-drilling spindle model including micro-drilling tool is derived. To express more realistic behaviors of the model, the Timoshenko beam model is employed. The dynamic responses of the micro-drill tool are obtained by utilizing the finite element method and Newmark’s method. The influences of the drill bit with high length to diameter are investigated in three cases as 15:1, 18:1, and 20:1 using the same 0.1 mm diameter drill at a rotational speed of 5×104 rpm during air cutting and cutting of the 6-layer FR-4 composite board. The hole-quality is used to discuss the influences of those drill bit aspect ratios.
Study of TiC Interaction and its Reaction Products with the Different Carbon Content Steels
Authors: Anikeev Andrey N. , Chumanov Ilia V. , Sedukhin Vadim
Published: January 2020

Study of TiC interaction with low-and high-carbon steel is presented in this article. Was carried out interaction thermodynamic modeling in the temperature range of 900-1800 °C, which showed that titanium carbide would dissolve in melts with these compositions, regardless of melt’s carbon content at given parameters. The obtained thermodynamic results were verified by conducting an experiment with high-temperature complex in order to study substances interaction processes. The obtained experimental samples were studied with scanning microscope as well as structure and compounds composition, obtained as a result of experiment mentioned above.
Acute transverse myelitis following carpet viper snakebite in Northeast Nigeria
Authors: Alkali Nura H. , Sa'ad Sulaiman T. , Saidu Abubakar , Dunga Jacob A. , Sa'ad Fadimatu K. , Ishaya Godiya
Published: January 2020

Snakebite is a major cause of death and disability in developing countries. The common clinical features of snake envenomation include bleeding, acute kidney injury, dilated pupils and muscle paralysis resulting from the deleterious effects of venom toxins on human plasma proteins, cell membranes, muscle fibers and vascular endothelium. Snakes also harbour pathogenic organisms that may infect bite victims during envenomation, but few studies have described this phenomenon. We herein report a rare case of acute transverse myelitis occurring after snakebite in Northeast Nigeria, and discuss the possible role of bacteria and viruses after excluding other potential causes of myelopathy. This knowledge may help improve the care of snakebite victims among internists and emergency physicians.
Left paranasal hemophilic pseudotumor in a 5-year-old boy: A case report
Authors: Yuguda Saleh , Girei Ahmed Iya , Dachi Rufai Abdu , Adamu Sani
Published: January 2020

Hemophilic pseudotumors are rare complications of hemophilia that are seen in 1-2% of patients commonly affecting patients with severe disease. Hemophilic pseudotumors occur as a result of recurrent poorly managed or untreated bleeding either in the soft tissue or bone. We report a 5-year-old boy with a previously undiagnosed hemophilia A who developed left paranasal swelling following a fall from a height. He was diagnosed with hemophilic pseudotumor and successfully managed conservatively with factor VIII replacement.
ALL RELATIVISTIC TRAJECTORIES OF BODIES ARE GEODESIC âˆ’ ET CETERA
Authors: Loinger Angelo , Marsico Tiziana
Published: January 2020

We prove in various ways that in general relativity (GR) the trajectories of the bodies are always geodesicâˆ’and therefore no gravitational wave (GW) is emitted. Then, we prove that the solutions of the Einstein field equations with a wave character do not have any physical existence.We prove finally the full unreliableness of the inflationary models. In Appendix some complementary remarks. The experimental and observational data corroborate our deductions.
INTEGRAZIONE DI DIGESTATO CHIARIFICATO COME FONTE DI AZOTO PER LA COLTIVAZIONE DI MICROALGHE
Authors: Algeri Alessandro
Published: January 2020

A possible alternative to the common fertilizer for feeding microalgae is the liquid fraction of digestate coming from the plants of the anaerobic digestion plants. However, the inclusion of this nutrient as such leads to problems in the growth in culture due to the high turbidity. Therefore, it has been necessary to plan and test a process of sustainable clarification in order to remove most of the suspended solids that are present. By using the culture medium coming from the filtration phase of the alga, it is possible to thermally flocculate the solids of different size present in the digestate, thus making it less turbid. Testing the use of this solution in cultures at Nannochloropsis of different scale, it was observed that they have good growth rates and no perceptible inhibition due to the inclusion of the digestate.
Field data for till samples collected in 2014, 2015, and 2016 in the southern Core Zone, Quebec and Labrador (NTS 23-P and 23-I)
Authors: Rice J M , McClenaghan M B , Paulen R
C , Pyne M D , Ross M , Campbell H
E
Published: January 2020

This Open File is a written summary of samples collected for indicator mineral and geochemical analysis during three summer field seasons (2014-2016) for the Hudson-Ungava Surficial Mapping and Geochemistry Activity. The activity was carried out under the larger
Geo-Mapping for Energy and Minerals Program (GEM 2) Hudson-Ungava Core Zone project. Field data and colour photographs will be presented for samples collected as part of a reconnaissance-scale till sampling and surficial mapping activity carried out by the Geological Survey of Canada across Quebec
and Labrador (NTS map sheets 23-I and 23-P) in collaboration with the Ministère de l'Énergie et des Ressources naturelles due Québec (MERNQ). This report also includes field data for previously collected samples from earlier GSC programs in 1986 and 1987 to allow for a comparison to
recent samples.
Therapy in the early stages for a head-injured patient
Authors: Maree H. P.
Published: January 2020

Waarmeming en evaluering vorm die belangrikste deel van behandeling in die vroee stadium na hoofbeserings. Pre-operatief behoort die pasient so gemaklik moontlik gemaak te word en by die hantering van so 'n pasient moet die bewuswording van die totale liggaamsbeeld in ag geneem en beklemtoon word. Post-operatief of post-traumaties behoort alle aspekte van die pasient se toestand, hierdie sosiale, sielkundige, fisiese en emosionele probleme, aandag te geniet. Die verskillende stadia van bewustheid word bespreek en daar word veral klem gelê op die feit dat personeel op normale toon met die pasient moet praat.Evaluering moet sistematies geskied en voortdurende, noukeurige waarmeming is noodsaaklik. Posisionering, passiewe bewegings en die beperking van hiperaktiwiteit moet volgens die pasient se toestand bepaal en toegepas word om optimum voordele vir die pasient in te hou. Verwaarlosing mag plaasvind as daar geen sigbare verbetering teenwoordig is nie en dit lyk asof die pasient nie saamwerk nie. Nogtans moet vroee behandeling daarop gemik wees om die pasient voor te berei vir latere behandeling. Doeltreffende, voldoende en effektiewe behandeling is dus die hoofdoel.
An approach to improving patterns of posture and movement
Authors: Maree H. P.
Published: January 2020

Daar is verskeie oorsake van rugpyn, maar meganiese  redistribusie van liggaamsgewig kan lei tot verligting van pyn. Die heropleiding van ’n posturale “patroon” word bespreek, asook oefeninge om die patroon neer te lê.  Dis van uiterste belang dat die pasiënt bewus word van sy bewegings- en ruspatrone en dit aanvaar as ’n permanente toestand eerder as ’n spesifieke oefening. So ’n patroon moet oorgedra word in daaglikse aktiwiteite en kinetiese hantering behoort deel van die korrektiewe opleiding te wees.
Physiotherapy in obstructive airways disease
Authors: Gaskell D.
Published: January 2020

The physiotherapy technique used in the treatment of asthma, chronic bronchitis and emphysema are very similar, but their application in the treatment of these diseases is totally different. For this reason the diseases will be dealt with separately.
Physiotherapy in the management of injuries to the chest
Authors: Blackwood S. H.M.
Published: January 2020

Die rol van die fisioterapeut in die hantering van 'n onstabiele (‘‘flail") loraks, hoe trompsnelheidswonde en veral in die intensiewe sorgeenheid word beskryf. Haar bekwaamheid in die hantering van ’n nood toestand, die voorkoming en behandeling van komplikasies, en finale rehabilitasie van die pasient is van innerste belang.
Physical properties of some mechanical vibrators and their clinical relevance
Authors: Brinkworth K. E.
Published: January 2020

Die korrekle tipe vibrator vir skeletspiersametrekking word bespreek. Dis belangrik dat die vibrasiefrekwensie korrek is vir terapie. Die frekwens van drie vibrators wat dikwels in die praktyk gebruik word, word bepaal. Die gegewens word vergelyk met die wat reeds in die literatuur beskryf is.
Alternative conceptions of students in Arabic language applications and the proper method of correcting them by using some active learning strategies: Adjective lesson as a model
Authors: al-Hasan Yahya al-Manakhrih al-Hasan Yahya al-Manakhrih
Published: January 2020

This study aimed to examine the effectiveness of some active learning strategies in adjusting students’ alternative perceptions about the concepts of the adjective lesson in the textbook of “My Language” taught in Saudi Middle Schools.To achieve this, a descriptive and quasi-experimental design approaches were employed. Beginning by identifying students’ alternative perceptions of the concepts of the adjective lesson, an evaluating test was applied for 120 students grade 9 in Jeddah.The result of the evaluating test has indicated that there were alternative perceptions of the concepts of the adjective lesson among students.Therefor, the researcher has designed a guide for using an active learning strategies for teachers to teach adjective lesson. To examine the effectiveness of active learning strategies in adjusting students’ alternative perceptions, a group of 30 students grade 9 in Jeddah were involved in the experimental. This group were taught the adjective lesson by traditional methods and also taught the lesson by using active learning strategies. The findings indicated that the students who were taught by active learning strategies are more likely to alter the alternative perceptions than those who were taught by traditional method.In light of the findings of the study, the researcher recommends that it is important to uncover the students’ alternative perceptions in the various Arabic language lessons, in order to help the students in adjusting the alternative perceptions by using active learning strategies , and improving teachers’ capabilities through pre-service and in-service training in applying several teaching strategies including the active learning strategies to improve the linguistic performance in the Arabic language.
Mineral content in local feed ingredients used by fish farmers in four different regions of Tanzania
Authors: Mmanda Francis P. , Lindberg Jan Erik , N. Haldén Anna , Lundh Torbjorn
Published: January 2020

This study investigated the content of selected minerals (P, Ca, K, Na, Mg, Fe and I) in local feed ingredients used by tilapia fish farmers in Tanzania. Analyses were performed on 26 local feed ingredients collected at four different geographical locations in Tanzania (Dar es Salaam, Morogoro, Mbeya and Mwanza). The samples were taken randomly from fish farmers, fish feed producers, fingerling producers and animal feed shops or centers near fish farms in each region. The results showed a wide range of mineral concentrations. The highest levels of P was found in fish skeletons (17.8 g kg-1), of Ca in limestone (107.3 g kg-1), of K in gallant soldier (51.0 g kg-1), of Na in marine shrimp (Exhippolysmata oplophoroides) (11.7 g kg-1), of Mg in prawn head waste (4.2 g kg-1), of Fe in azolla (2355 mg kg-1) and of I in full fat soybean (447 mg kg-1). The data on mineral content in feed ingredients can be used as a platform for better-targeted feed formulation for tilapia farming systems. In conclusion, the data suggest that if more than two ingredients are used in the diet, this may be sufficient to meet the mineral requirements of all cultured tilapia species and their hybrids, without inclusion of any mineral premix.
Re-description and new records of a poorly known leucosiid crab, Merocryptus boletisculpta Zarenkov, 1994 (Crustacea, Decapoda, Brachyura)
Authors: Galil Bella S.
Published: January 2020

Sixty-nine specimens of the rare leucosiid crab Merocryptus boletisculpta are reported from Walters Shoal, an isolated seamount in the southwestern Indian Ocean. The species has previously only been known from the type series collected during the R/V Vityaz 1988-1989 expedition. The species is re-described, illustrated, and colour photographs are provided.
Biophysical factors influencing the choice of nesting sites by the green turtle (Chelonia mydas) on the Kenyan coast
Authors: Obare Fridah D. , Chira Robert , Sigana Dorcus , Wamukota Andrew
Published: January 2020

The green turtle (Chelonia mydas) is the most common sea turtle nesting along Kenya’s coastline. Varying biophysical factors influence choice of nesting sites where eggs are laid. This study was conducted between February and November 2016 and was designed to establish the relationship between numbers of C. mydas nests on the beach and biophysical variables such as vegetation cover, organic matter content (OMC), beach width, and beach slope. Multiple regression analysis was employed to assess the factors that contribute to the number of C. mydas nests on a beach. This analysis did not allow prediction of the number of nests in a statistically significant way (F (4, 26) = 0.094, p > 0.05, R = 0.120). However, there was a decrease in the number of nests with increased vegetation cover (b = - 0.013), OMC (b = - 8.114), beach width (b = - 0.089) and slope of the beach (b = - 0.352). Approximately 70% of nests occurred on beaches with medium and fine sand. Beaches with intense human activities were associated with high OMC which significantly affected the number of nests on the beach. It is therefore recommended that existing laws should be enforced to control beach development and human activities along the Kenyan coast to protect nest sites. Additionally, long term monitoring should be put in place to evaluate the impact of human disturbance on the favourable biophysical factors influencing the number of nests on a beach, as a management tool in the conservation of C. mydas.
Stock status and some biological aspects of Lethrinus lentjan (Lacapede, 1802) from the south coast of Kenya
Authors: Mrombo Nathan L. , Mlewa Chrisestom , Munga Cosmas N. , Manyala Julius O.
Published: January 2020

The Pinkear Emperor (Lethrinus lentjan, Laćepède, 1802) is among the three demersal species dominating fish catches in the artisanal fishery on the Kenyan coast. Available data indicate that total landings of L. lentjan have declined over the past decade due to possible over-exploitation. This paper provides a brief account of the stock status of this species and biological aspects including length-weight relationship, body condition, and reproduction from a total of 575 fish specimens sampled. Sampling was done at Msambweni, Shimoni, Majoreni and Vanga fish landing sites on the south coast of Kenya from September 2016 to February 2017. Individual total length (TL, cm) and body weight (BW, g) was measured on site while some specimens were dissected for sex and gonad maturity analysis. Mortality, exploitation rate, length-weight relationship, condition factor, fecundity, and size at maturity (L50) were determined. Length frequency analysis indicated that L. lentjan was exploited above the optimum level, at E = 0.55 (exploitation rate). Growth was allometric with the length exponent (b = 2.95) being significantly <3. Mean fecundity was 89,573 ± 9,841 eggs/female/year. Gonadosomatic index was highest in January (2.08 ± 0.20) suggesting a possible peak spawning period at this time. The study provides a brief scientific overview of L. lentjan as a baseline for future in-depth biological studies of this species along the Kenyan coast.
The biology of Goldsilk Sea Bream (family: Sparidae) from the inshore waters of north coast Kenya
Authors: Anam Rashid O. , Munga Cosmas N. , Gonda James R.
Published: January 2020

The biology of the sparid, Acanthopagrus berda (goldsilk sea bream) was investigated using catch samples obtained from artisanal fishers at selected fish landing sites in the Marereni and Ngomeni fishing areas on the north coast of Kenya. This species has not previously been studied in Kenya although it forms significant proportions of artisanal fish landings and is also a promising aquaculture species. In order to contribute to knowledge of this species, the length-weight relationship, condition factor and feeding preference for prey items were studied in a total of 751 specimens sampled from July 2013 to July 2014. Length-weight relationships for male and female individuals from both fishing areas were strongly correlated (Males: Marereni - R2 = 0.920, Ngomeni - R2 = 0.983; Females: Marereni - R2 = 0.966, Ngomeni - R2 = 0.941). The condition factor of mixed sexes was not significantly different between the two fishing areas (Marereni 2.15 ± 0.08; Ngomeni 2.05 ± 0.02) at p > 0.05. Gut content analysis recorded a total of 5 taxa in the diet (gastropods, molluscs, detritus, crustaceans and fish). The overall sample was dominated by female individuals with an overall sex ratio of females (405 individuals) to males (338 individuals) of 1:0.8 being significantly different at p < 0.05. The species exhibited isometric and positive allometric growth patterns, indicative of the physiological well-being of this species on the north coast of Kenya. Gonadal maturation occurred throughout the year with peaks in July, August and September. However, more work is needed on the biology, distribution, spawning grounds, behavior, and migration patterns along the Kenyan coast.
Trends in global tropospheric hydroxyl radical and methane lifetime since 1850 from AerChemMIP
Authors: Stevenson David S. , Zhao Alcide , Naik Vaishali , O'Connor Fiona M. , Tilmes Simone , Zeng Guang , Murray Lee T. , Collins William J. , Griffiths Paul , Shim Sungbo , Horowitz Larry W. , Sentman Lori , Emmons Louisa
Published: January 2020

Abstract. We analyse historical (1850–2014) atmospheric hydroxyl (OH) and methane lifetime data from CMIP6/AerChemMIP simulations. Global OH changed little from 1850 up to around 1980, then increased by around 10 %, with an associated reduction in methane lifetime. The model-derived OH trend since 1980 differs from trends found in several studies that infer OH from inversions of methyl chloroform measurements; however, these inversions are poorly constrained and contain large uncertainties that do not rule out the possibility of recent positive OH trends. The recent increases in OH that we find are consistent with one previous study that assimilated global satellite-derived carbon monoxide (CO) over the period 2002–2013. The upward trend in modelled OH since 1980 was mainly driven by changes in anthropogenic Near-Term Climate Forcer emissions (increases in anthropogenic nitrogen oxides and decreases in CO). Increases in halocarbon emissions since 1950 have made a small contribution to the increase in OH, whilst increases in aerosol-related emissions have slightly reduced OH. Halocarbon emissions have dramatically reduced the stratospheric methane lifetime, by about 15–40 %, which has been assumed to not change in most previous studies. We find that whilst the main driver of atmospheric methane increases since 1850 is emissions of methane itself, increased ozone precursor emissions have significantly modulated (in general reduced) methane trends. Halocarbon and aerosol emissions are found to have relatively small contributions to methane trends. All these factors, together with changes and variations of climate and climate-driven natural emissions, need to be included in order to fully explain OH and methane trends since 1850; these factors will also be important for future trends.
Improved cloud detection over sea ice and snow during Arctic summer using MERIS data
Authors: Istomina Larysa , Marks Henrik , Huntemann Marcus , Heygster Georg , Spreen Gunnar
Published: January 2020

Abstract. The historic MERIS sensor onboard Envisat (2002–2012) provides valuable remote sensing data for the retrievals of the summer sea ice in the Arctic. MERIS data together with the data of recently launched successor OLCI onboard Sentinel 3 (2016 onwards) can be used to assess the long-term change of the Arctic summer sea ice. An important prerequisite to a high-quality remote sensing dataset is an accurate separation of cloudy and clear pixels to ensure lowest cloud contamination of the end product. The presence of 15 VIS and NIR spectral channels of MERIS allow high quality retrievals of sea ice albedo and melt pond fraction, but make cloud screening a challenge as snow, sea ice and clouds have similar optical features in the available spectral range of 412.5–900 nm. In this paper, we present a new cloud screening method MECOSI (MERIS Cloud screening Over Sea Ice) for the retrievals of spectral albedo and melt pond fraction (MPF) from MERIS. The method utilizes all 15 MERIS channels, including the oxygen A absorption band. For the latter, a smile effect correction has been developed to ensure high quality screening throughout the whole swath. Three years of reference cloud mask from AATSR (Istomina et al., 2010) have been used to train the Bayesian cloud screening for the available limited MERIS spectral range. Whiteness and brightness criteria as well as normalized difference thresholds have been used as well. The comparison of the developed cloud mask to the operational AATSR and MODIS cloud masks shows a considerable improvement in the detection of clouds over snow and sea ice, with about 10 % false clear detections during May–July and less than 5 % false clear detections in the rest of the melting season. This seasonal behaviour is expected as the sea ice surface is generally brighter and more challenging for cloud detection in the beginning of the melting season. The effect of the improved cloud screening on the MPF/albedo datasets is demonstrated on both temporal and spatial scales. In the absence of cloud contamination, the time sequence of MPFs displays a greater range of values throughout the whole summer. The daily maps of the MPF now show spatially uniform values without cloud artefacts, which were clearly visible in the previous version of the dataset. The resulting cloud mask for the MERIS operating time, as well as the improved MPF/albedo datasets are available as swath data and daily means on the ftp server of the University of Bremen https://seaice.uni-bremen.de/data/meris/gridded_cldscr/.
Influence of late Quaternary climate on the biogeography of Neotropical aquatic species as reflected by non-marine ostracodes
Authors: Cohuo Sergio , Macario-González Laura , Wagner Sebastian , Naumann Katrin , Echeverría-Galindo Paula , Pérez Liseth , Curtis Jason , Brenner Mark , Schwalb Antje
Published: January 2020

Abstract. We evaluated how ranges of four endemic and non-endemic aquatic ostracode
species changed in response to long-term (glacial–interglacial cycles) and
abrupt climate fluctuations during the last 155 kyr in the northern
Neotropical region. We employed two complementary approaches, fossil records
and species distribution models (SDMs). Fossil assemblages were obtained
from sediment cores PI-1, PI-2, PI-6 and Petén-Itzá 22-VIII-99 from
the Petén Itzá Scientific Drilling Project, Lake Petén Itzá,
Guatemala. To obtain a spatially resolved pattern of (past) species
distribution, a downscaling cascade is employed. SDMs were reconstructed
for the last interglacial (∼120 ka), the last glacial maximum (∼22 ka) and the middle Holocene (∼6 ka). During glacial and interglacial cycles and marine isotope stages (MISs),
modelled paleo-distributions and paleo-records show the nearly continuous
presence of endemic and non-endemic species in the region, suggesting
negligible effects of long-term climate variations on aquatic niche
stability. During periods of abrupt ecological disruption such as Heinrich
Stadial 1 (HS1), endemic species were resilient, remaining within their
current areas of distribution. Non-endemic species, however, proved to be
more sensitive. Modelled paleo-distributions suggest that the geographic
range of non-endemic species changed, moving southward into Central America.
Due to the uncertainties involved in the downscaling from the global
numerical to the highly resolved regional geospatial statistical modelling,
results can be seen as a benchmark for future studies using similar
approaches. Given relatively moderate temperature decreases in Lake
Petén Itzá waters (∼5 ∘C) and
the persistence of some aquatic ecosystems even during periods of severe drying
in HS1, our data suggest (1) the existence of micro-refugia and/or (2) continuous
interaction between central metapopulations and surrounding populations,
enabling aquatic taxa to survive climate fluctuations in the northern
Neotropical region.
A meta-analysis of microcosm experiments shows that dimethyl sulfide (DMS) production in polar waters is insensitive to ocean acidification
Authors: Hopkins Frances E. , Nightingale Philip D. , Stephens John A. , Moore C. Mark , Richier Sophie , Cripps Gemma L. , Archer Stephen D.
Published: January 2020

Abstract. Emissions of dimethylsulfide (DMS) from the polar oceans play a
key role in atmospheric processes and climate. Therefore, it is important to
increase our understanding of how DMS production in these regions may
respond to climate change. The polar oceans are particularly vulnerable to
ocean acidification (OA). However, our understanding of the polar DMS
response is limited to two studies conducted in Arctic waters, where in both
cases DMS concentrations decreased with increasing acidity. Here, we report
on our findings from seven summertime shipboard microcosm experiments
undertaken in a variety of locations in the Arctic Ocean and Southern Ocean.
These experiments reveal no significant effects of short-term OA on the net
production of DMS by planktonic communities. This is in contrast to similar
experiments from temperate north-western European shelf waters where surface ocean
communities responded to OA with significant increases in dissolved DMS
concentrations. A meta-analysis of the findings from both temperate and
polar waters (n=18 experiments) reveals clear regional differences in the
DMS response to OA. Based on our findings, we hypothesize that the
differences in DMS response between temperate and polar waters reflect the
natural variability in carbonate chemistry to which the respective
communities of each region may already be adapted. If so, future temperate
oceans could be more sensitive to OA, resulting in an increase in DMS
emissions to the atmosphere, whilst perhaps surprisingly DMS emissions from
the polar oceans may remain relatively unchanged. By demonstrating that DMS
emissions from geographically distinct regions may vary in their response to
OA, our results may facilitate a better understanding of Earth's future
climate. Our study suggests that the way in which processes that generate
DMS respond to OA may be regionally distinct, and this should be taken into
account in predicting future DMS emissions and their influence on Earth's
climate.
Linking climatic-driven iron toxicity and water stress to a massive mangrove dieback
Authors: Sippo James Z. , Santos Isaac R. , Sanders Christian J. , Gadd Patricia , Hua Quan , Lovelock Catherine , Santini Nadia S. , Johnston Scott G. , Harada Yota , Reithmeir Gloria , Maher Damien T.
Published: January 2020

Abstract. A massive mangrove dieback event occurred in 2015/2016 along ~ 1000 km of pristine coastline in the Gulf of Carpentaria, Australia. To gain insights into dieback drivers, we combine sediment and wood chronologies to analyze geochemical and climatic changes. The unique combination of low rainfall and low sea level observed during the dieback event was unprecedented in the previous three decades. Multiple lines of evidence from iron (Fe) chronologies in wood and sediment, wood densities and mangrove water use efficiency suggest low water availability within the dead mangrove forest. Wood and sediment chronologies suggest a rapid and large mobilization of sedimentary Fe, which was likely associated with pyrite oxidation within mangrove sediments. High resolution elemental analysis of wood cross sections revealed 30–90 fold increase in Fe concentrations in dead mangrove areas just prior to mortality. Fe concentrations in wood samples correlated strongly with the El Niño Southern Oscillation (ENSO) index, suggesting ENSO was a major driver of Fe mobilization. Large Fe losses from sediments during the dieback are consistent with Fe uptake in the trees, further implying sediment pyrite oxidation. If our data are representative of the entire dieback region, we estimate that the dieback drove the mobilization and loss of 50 ± 173 Gg Fe, equivalent to 8–50 % of annual global atmospheric Fe deposition into the oceans, which is one of the major drivers of surface ocean productivity. Overall, our observations support the hypothesis that the forest dieback was associated with low water availability and Fe toxicity driven by a strong ENSO event.
Vascular plants affect properties and decomposition of moss-dominated peat, particularly at elevated temperatures
Authors: Zeh Lilli , Igel Theresa Marie , Schellekens Judith , Limpens Juul , Bragazza Luca , Kalbitz Karsten
Published: January 2020

Abstract. Peatlands, storing significant amounts of carbon are extremely vulnerable to climate change. The effects of climate change are projected to lead to a vegetation shift from Sphagnum mosses to sedges and shrubs. Impacts on the present moss-dominated peat remain largely unknown. In this study, we used a multi proxy approach to investigate the influence of contrasting vascular plant types (sedges, shrubs) on peat chemistry and decomposition. Peat cores of 20 cm depth and plant material (Sphagnum spp., Calluna vulgaris, Eriophorum vaginatum) from two ombrotrophic peatlands in the Italian Alps with a mean annual temperature difference of 1.4 °C were analysed. Peat cores were taken under adjacent shrub and sedge plants growing at the same height above the water table. We used carbon, nitrogen and their stable isotopes to assess general patterns in the degree of decomposition across sampling locations and depths. In addition, analytical pyrolysis was applied to disentangle effects of vascular plants (sedge, shrub) on chemical properties and decomposition of the moss-dominated peat. Pyrolysis data confirmed that Sphagnum moss dominated the present peat irrespectively of depth. Nevertheless, vascular plants contributed to peat properties as revealed by e.g. pyrolysis products of lignin. The degree of peat decomposition increased with depth as shown by e.g. decreasing amounts of the pyrolysis product of sphagnum acid and increasing δ13C with depth. Multiple parameters also revealed a higher degree of decomposition of Sphagnum-dominated peat collected under sedges than under shrubs, particularly at the high temperature site. Surprisingly, temperature effects on peat decomposition were less pronounced than those of sedges. Our results imply that vascular plants affect the decomposition of the existing peat formed by Sphagnum, particularly at elevated temperature. These results suggest that changes in plant functional types may have a stronger impact on the soil carbon feedback in a warmer world than hitherto assumed.
Large-scale features and evaluation of the PMIP4-CMIP6 midHolocene simulations
Authors: Brierley Chris M. , Zhao Anni , Harrison Sandy P. , Braconnot Pascale , Williams Charles J. R. , Thornalley David J. R. , Shi Xiaoxu , Peterschmitt Jean-Yves , Ohgaito Rumi , Kaufman Darrell S. , Kageyama Masa , Hargreaves Julia C. , Erb Micheal P. , Emile-Geay Julien , D'Agostino Roberta , Chandan Deepak , Carré Matthieu , Bartlein Patrick , Zheng Weipeng , Zhang Zhongshi , Zhang Qiong , Yang Hu , Volodin Evgeny M. , Tomas Robert A. , Routson Cody , Peltier W. Richard , Otto-Bliesner Bette , Morozova Polina A. , McKay Nicholas P. , Lohmann Gerrit , Legrande Allegra N. , Guo Chuncheng , Cao Jian , Brady Esther , Annan James D. , Abe-Ouchi Ayako
Published: January 2020

Abstract. The mid-Holocene (6000 years ago) is a standard experiment for the evaluation of the simulated response of global climate models using paleoclimate reconstructions. The latest mid-Holocene simulations are a contribution by the Palaeoclimate Model Intercomparison Project (PMIP4) to the current phase of the Coupled Model Intercomparison Project (CMIP6). Here we provide an initial analysis and evaluation of the results of the experiment for the mid-Holocene. We show that state-of-the-art models produce climate changes that are broadly consistent with theory and observations, including increased summer warming of the northern hemisphere and associated shifts in tropical rainfall. Many features of the PMIP4-CMIP6 simulations were present in the previous generation (PMIP3-CMIP5) of simulations. The PMIP4-CMIP6 ensemble for the mid-Holocene has a global mean temperature change of −0.3 K, which is −0.2 K cooler that the PMIP3-CMIP5 simulations predominantly as a result of the prescription of realistic greenhouse gas concentrations in PMIP4-CMIP6. Neither this difference nor the improvement in model complexity and resolution seems to improve the realism of the simulations. Biases in the magnitude and the sign of regional responses identified in PMIP3-CMIP5, such as the amplification of the northern African monsoon, precipitation changes over Europe and simulated aridity in mid-Eurasia, are still present in the PMIP4-CMIP6 simulations. Despite these issues, PMIP4-CMIP6 and the mid-Holocene provide an opportunity both for quantitative evaluation and derivation of emergent constraints on climate sensitivity and feedback strength.