Search

Your search keyword '"Marah, H."' showing total 43 results
Start Over Author "Marah, H."
43 results on '"Marah, H."'

1. A functional schizophrenia-associated genetic variant near the TSNARE1 and ADGRB1 genes

Author

Marah H. Wahbeh, Rachel J. Boyd, Christian Yovo, Bailey Rike, Andrew S. McCallion, and Dimitrios Avramopoulos

Subjects
gene regulation, genome editing, CRISPR, genetic association, schizophrenia, psychosis, Genetics, QH426-470
Abstract

Summary: Recent collaborative genome-wide association studies (GWAS) have identified >200 independent loci contributing to risk for schizophrenia (SCZ). The genes closest to these loci have diverse functions, supporting the potential involvement of multiple relevant biological processes, yet there is no direct evidence that individual variants are functional or directly linked to specific genes. Nevertheless, overlap with certain epigenetic marks suggest that most GWAS-implicated variants are regulatory. Based on the strength of association with SCZ and the presence of regulatory epigenetic marks, we chose one such variant near TSNARE1 and ADGRB1, rs4129585, to test for functional potential and assay differences that may drive the pathogenicity of the risk allele. We observed that the variant-containing sequence drives reporter expression in relevant neuronal populations in zebrafish. Next, we introduced each allele into human induced pluripotent cells and differentiated four isogenic clones homozygous for the risk allele and five clones homozygous for the non-risk allele into neural progenitor cells. Employing RNA sequencing, we found that the two alleles yield significant transcriptional differences in the expression of 109 genes at a false discovery rate (FDR) of

Published
2024
Full Text
View/download PDF

3. CRISPR Del/Rei: a simple, flexible, and efficient pipeline for scarless genome editing

Author

Kyra L. Feuer, Marah H. Wahbeh, Christian Yovo, Eman Rabie, Anh-Thu N. Lam, Sara Abdollahi, Lindsay J. Young, Bailey Rike, Akul Umamageswaran, and Dimitrios Avramopoulos

Subjects
Medicine, Science
Abstract

Abstract Scarless genome editing of induced pluripotent stem cells (iPSCs) is crucial for the precise modeling of genetic disease. Here we present CRISPR Del/Rei, a two-step deletion-reinsertion strategy with high editing efficiency and simple PCR-based screening that generates isogenic clones in ~ 2 months. We apply our strategy to edit iPSCs at 3 loci with only rare off target editing.

Published
2022
Full Text
View/download PDF

10. Isotope characterization of shallow aquifers in the Horombe region, South of Madagascar

Author

Fareze, L. P., Rajaobelison, J., Ramaroson, V., Andriambololona, Raoelina, Andriamiarintsoa, G., Razafitsalama, P. R., Rahobisoa, J. J., Randrianarison, H., Ranaivoarisoa, A., and Marah, H.

Subjects
Physics - Geophysics
Abstract

The present study deals with the problem of evaluation of the recharge mechanism and the characterization of the groundwater flow system in the basement shallow aquifer, which is one of the groundwater resource in the semi-arid South region of Madagascar. Stable isotopes (deuterium and oxygen-18) and tritium are used to achieve with accuracy the hydrogeological and geochemical dynamics study. Chemical analysis is used to provide complementary information to the investigation. A space distribution of tritium concentration and isotopic composition in groundwater shows evidence of two opposite categories of aquifers, which is confirmed by the chemical analysis results and by the geological features of the study site. Some groundwater flow path directions have been identified in the study area thanks to the tritium concentration space distribution and the geological formation. Besides, the groundwater recharge of the shallow aquifers in the South of Madagascar has been characterized by the exponential mixing model., Comment: 6 pages, 6 figures

Published
2012

11. A Missense Variant in CASKIN1’s Proline-Rich Region Segregates with Psychosis in a Three-Generation Family

Author

Wahbeh, Marah H., primary, Peng, Xi, additional, Bacharaki, Sofia, additional, Hatzimanolis, Alexandros, additional, Dimitrakopoulos, Stefanos, additional, Wohler, Elizabeth, additional, Yang, Xue, additional, Yovo, Christian, additional, Maher, Brady J., additional, Sobreira, Nara, additional, Stefanis, Nikos C., additional, and Avramopoulos, Dimitrios, additional

Published
2023
Full Text
View/download PDF

12. An Interactive Protocol for In-Classroom DNA Extraction

Author

Levesque, Danica C., primary, Wallis, Athena L., additional, Daypuk, Jenna, additional, Petahtegoose, Jesse, additional, Slobodian, Mitchell, additional, Sutherland-Hutchings, Allie K., additional, Black, Ian, additional, Vélez, Jessica M., additional, Abood, Abdullah, additional, Wahbeh, Marah H., additional, Cejas, Romina B., additional, Cisneros, Angel F., additional, McNeil, Laerie, additional, Konno, Kento, additional, McGregor, Lissa, additional, Faroqi, Birha, additional, Bautisa, Carla, additional, Rajpurohit, Subhash, additional, Garg, Divita, additional, Zhu, Jiechun, additional, Yang, Guangdong, additional, Arthur, Solomon, additional, and Merritt, Thomas J. S., additional

Published
2023
Full Text
View/download PDF

15. A Missense Variant in CASKIN1’s Proline-Rich Region Segregates with Psychosis in a Three-Generation Family

Author

Marah H. Wahbeh, Xi Peng, Sofia Bacharaki, Alexandros Hatzimanolis, Stefanos Dimitrakopoulos, Elizabeth Wohler, Xue Yang, Christian Yovo, Brady J. Maher, Nara Sobreira, Nikos C. Stefanis, and Dimitrios Avramopoulos

Subjects
schizophrenia, bipolar disorder, NRXN1, iPSC, stem cells, psychiatric disease, Genetics, psychosis, CRISPR/Cas9, CASKIN1, CASK, Genetics (clinical)
Abstract

The polygenic nature of schizophrenia (SCZ) implicates many variants in disease development. Rare variants of high penetrance have been shown to contribute to the disease prevalence. Whole-exome sequencing of a large three-generation family with SCZ and bipolar disorder identified a single segregating novel, rare, non-synonymous variant in the gene CASKIN1. The variant D1204N is absent from all databases, and CASKIN1 has a gnomAD missense score Z = 1.79 and pLI = 1, indicating its strong intolerance to variation. We find that introducing variants in the proline-rich region where the D1204N resides results in significant cellular changes in iPSC-derived neurons, consistent with CASKIN1’s known functions. We observe significant transcriptomic changes in 368 genes (padj < 0.05) involved in neuronal differentiation and nervous system development. We also observed nominally significant changes in the frequency of action potentials during differentiation, where the speed at which the edited and unedited cells reach the same level of activity differs. Our results suggest that CASKIN1 is an excellent gene candidate for psychosis development with high penetrance in this family.

Published
2023
Full Text
View/download PDF

18. Awareness of Delirium by ICU Nurses

Author

Aseel A. Alwredat, Imad T. Asmar, Khalid S. Yaseen, Maram K. Jaghama, Yaqin F. Khawaja, and Marah H. Sadaqa

Subjects
health care facilities, manpower, and services, Nurses, 030204 cardiovascular system & hematology, Icu nurses, Critical Care Nursing, law.invention, 03 medical and health sciences, 0302 clinical medicine, law, Health care, medicine, Humans, Nursing management, West bank, 030504 nursing, business.industry, Delirium, medicine.disease, Intensive care unit, Test (assessment), Intensive Care Units, Cross-Sectional Studies, Quality of Life, Christian ministry, Medical emergency, medicine.symptom, 0305 other medical science, business
Abstract

Delirium is a critical issue in the intensive care unit (ICU), and the correct diagnosis and treatment of this disorder by the ICU team are doubtful on many occasions due to a lack of information. This research is intended to test the awareness and control of ICU delirium by the ICU nurses. A nonexperimental, quantitative, descriptive, cross-sectional study was conducted using a previously adopted and translated to Arabic and validated questionnaire. The sample include nurses who work in ICUs of 10 Palestinian hospitals (private and public) located in the West Bank and Jerusalem participated in this study; each gave consent to be part of this study. Approval was received from the Palestinian Ministry of Health and the Ethical Committee at Birzeit University. Version 19 of the Social Sciences Statistical Package (SPSS) software was used to analyze the data. The results showed that ICU nurses hold moderate to low levels of knowledge and lack of adequate clinical experience to handle delirium. Delirium is a common complication in the ICU that increases morbidity and mortality and increases the length of ICU stay, therefore the cost of health care rise and the quality of life is decreased. In clinical practice, there are no assessment guidelines and protocols for patients with delirium.

Published
2021

19. CRISPR Del/Rei: A simple, flexible, and efficient pipeline for scarless genome editing

Author

Marah H. Wahbeh, Kyra L. Feuer, Christian Yovo, Eman Rabie, Anh-Thu N. Lam, Sara Abdollahi, Lindsay J. Young, Bailey Rike, Akul Umamageswaran, and Dimitrios Avramopoulos

Subjects
Gene Editing, Multidisciplinary, Genome, Human, Computer science, Cas9, Induced Pluripotent Stem Cells, Computational biology, Pipeline (software), DNA sequencing, Human disease, Genome editing, Humans, CRISPR, Clustered Regularly Interspaced Short Palindromic Repeats, Clone (computing), CRISPR-Cas Systems, Selection (genetic algorithm)
Abstract

Scarless genome editing is an important tool for the accurate recapitulation of genetic variation in human disease models. Various CRISPR/Cas9-based scarless editing methods have been reported. However, some of these methods have low editing efficiency (1-5%) and require manual selection of hundreds of clones to reach the desired number. Other protocols use large selection cassettes with laborious vector assembly and specialized reagents and equipment, or have poorly understood off-target effects. To address these limitations, we developed a simple, highly efficient scarless editing strategy to edit DNA sequences in induced pluripotent stem cells, which we call CRISPR Del/Rei. This novel editing strategy consists of a two-step deletion-reinsertion strategy that produces isogenic clones in ~8 weeks using accessible, user-friendly reagents. The editing efficiency ranges from ~15-100% for Step 1 and ~5-20% for Step 2 after selection, which greatly reduces the amount of required manual clone isolation. Screening the transfected bulk cells and the individual clones is rapid and simple, consisting of PCR and gel electrophoresis. Despite the two editing steps, off-target effects are rare. Additionally, the experiment is well-controlled because the same protocol generates isogenic clones carrying all variant alleles. In this way, CRISPR Del/Rei serves as a valuable addition to the evolving CRISPR/Cas9 gene-editing toolset.

Published
2021
Full Text
View/download PDF

20. Modeling Psychiatric Disorder Biology with Stem Cells

Author

Kyra L. Feuer, Marah H. Wahbeh, Debamitra Das, and Dimitrios Avramopoulos

Subjects
Neurons, medicine.medical_specialty, Bipolar Disorder, Cellular differentiation, Induced Pluripotent Stem Cells, Disease, Biology, medicine.disease, Embryonic stem cell, Article, 030227 psychiatry, 03 medical and health sciences, Psychiatry and Mental health, Phenotype, 0302 clinical medicine, Genome editing, Schizophrenia, medicine, Humans, Autism, Stem cell, Induced pluripotent stem cell, Psychiatry, 030217 neurology & neurosurgery
Abstract

PURPOSE OF REVIEW: We review the ways in which stem cells are used in psychiatric disease research, including the related advances in gene-editing and directed cell differentiation. RECENT FINDINGS: The recent development of induced pluripotent stem cell (iPSC) technologies has created new possibilities for the study psychiatric disease. iPSCs can be derived from patients or controls and differentiated to an array of neuronal and non-neuronal cell types. Their genomes can be edited as desired, and they can be assessed for a variety of phenotypes. This makes them especially interesting for studying genetic variation, which is particularly useful today now that our knowledge on the genetics of psychiatric disease is quickly expanding. SUMMARY: The recent advances in cell engineering have led to powerful new methods for studying psychiatric illness including schizophrenia, bipolar disorder, and autism. There is a wide array of possible applications as illustrated by the many examples from the literature, most of which are cited here.

Published
2020
Full Text
View/download PDF

21. Awareness of Delirium by ICU Nurses

Author

Asmar, Imad T., primary, Yaseen, Khalid S., additional, Jaghama, Maram K., additional, Khawaja, Yaqin F., additional, Alwredat, Aseel A., additional, and Sadaqa, Marah H., additional

Published
2021
Full Text
View/download PDF

26. Gene-Environment Interactions in Schizophrenia: A Literature Review

Author

Dimitrios Avramopoulos and Marah H. Wahbeh

Subjects
cannabis, Psychosis, Toxoplasma gondii, Review, QH426-470, Risk Factors, Genetics, medicine, Animals, Humans, psychosis, Gene, Genetics (clinical), biology, gene-environment interactions, Heritability, biology.organism_classification, Mental illness, medicine.disease, schizophrenia, Psychotic Disorders, Schizophrenia, polygenic risk score, Psychosocial stress, Gene-Environment Interaction, Cannabis, Psychology, environment, Urban environment, Clinical psychology
Abstract

Schizophrenia is a devastating mental illness with a strong genetic component that is the subject of extensive research. Despite the high heritability, it is well recognized that non-genetic factors such as certain infections, cannabis use, psychosocial stress, childhood adversity, urban environment, and immigrant status also play a role. Whenever genetic and non-genetic factors co-exist, interaction between the two is likely. This means that certain exposures would only be of consequence given a specific genetic makeup. Here, we provide a brief review of studies reporting evidence of such interactions, exploring genes and variants that moderate the effect of the environment to increase risk of developing psychosis. Discovering these interactions is crucial to our understanding of the pathogenesis of complex disorders. It can help in identifying individuals at high risk, in developing individualized treatments and prevention plans, and can influence clinical management.

Published
2021
Full Text
View/download PDF

28. Spatio‐temporal patterns of tree growth as related to carbon isotope fractionation in European forests under changing climate

Author

Shestakova, T.A., Voltas, J., Saurer, M., Berninger, F., Esper, J., Andreu‐Hayles, L., Daux, V., Helle, G., Leuenberger, M., Loader, N.J., Masson-Delmotte, V., Saracino, A., Waterhouse, J.S., Schleser, G.H., Bednarz, Z., Boettger, Tatjana, Dorado‐Liñán, I., Filot, M., Frank, D., Grabner, M., Haupt, Marika, Hilasvuori, E., Jungner, H., Kalela-Brundin, M., Krąpiec, M., Marah, H., Pawełczyk, S., Pazdur, A., Pierre, M., Planells, O., Pukienė, R., Reynolds‐Henne, C.E., Rinne‐Garmston, K.T., Rita, A., Sonninen, E., Stiévenard, M., Switsur, V.R., Szychowska‐Kra̧piec, E., Szymaszek, M., Todaro, L., Treydte, K., Vitas, A., Weigl, M., Wimmer, R., Gutiérrez, E., Shestakova, T.A., Voltas, J., Saurer, M., Berninger, F., Esper, J., Andreu‐Hayles, L., Daux, V., Helle, G., Leuenberger, M., Loader, N.J., Masson-Delmotte, V., Saracino, A., Waterhouse, J.S., Schleser, G.H., Bednarz, Z., Boettger, Tatjana, Dorado‐Liñán, I., Filot, M., Frank, D., Grabner, M., Haupt, Marika, Hilasvuori, E., Jungner, H., Kalela-Brundin, M., Krąpiec, M., Marah, H., Pawełczyk, S., Pazdur, A., Pierre, M., Planells, O., Pukienė, R., Reynolds‐Henne, C.E., Rinne‐Garmston, K.T., Rita, A., Sonninen, E., Stiévenard, M., Switsur, V.R., Szychowska‐Kra̧piec, E., Szymaszek, M., Todaro, L., Treydte, K., Vitas, A., Weigl, M., Wimmer, R., and Gutiérrez, E.

Published
2019

29. Estimation of soil evaporation and infiltration losses using stables isotopes, fluxmeter and eddy-covariance system for citrus orchards in a semi-arid region (Morocco)

Author

Amenzou, N., Marah, H., Raibi, F., Ezzahar, S., Khabba, S., Jarlan, Lionel, and Ismaili, M.

Subjects
EVAPORATION, EVAPOTRANSPIRATION, INFILTRATION, HUMIDITE DU SOL, BILAN HYDRIQUE, ANALYSE ISOTOPIQUE, CULTURE IRRIGUEE, AGRUME, RUISSELLEMENT
Abstract

In arid and semi-arid regions water scarcity is one of the main limiting factors for economic growth. In the context, an experimental setup was conceived to monitor seasonal water consumption of citrus plant irrigated by drip irrigation system in Agafay station, middle of Morocco. For that, an Eddy-Covariance system, meteorological station, fluxmeter, as well as measurements of soil moisture and temperature were continuously operated during experimentation. The stable isotope was used to partition Evapotranspiration (ET) components. By using the water balance equation, the results showed that about 37% of total irrigation and rainfall is lost by infiltration and runoff. Additionally, the partitioning of evapotranspiration using the stable isotope showed that soil evaporation is very small compared to the transpiration at least during tow sampling days. This result confirms that the irrigation method applied by the farmer was very appropriate for the orchard but it is necessary to re-examine amount of water applied and timing of irrigation in order to minimise the loss by infiltration

Published
2013

30. Water-use efficiency and transpiration across European forests during the Anthropocene

Author

Frank, D.C., Poulter, B., Saurer, M., Esper, J., Huntingford, C., Helle, G., Treydte, K., Zimmermann, N.E., Schleser, G.H., Ahlström, A., Ciais, P., Friedlingstein, P., Levis, S., Lomas, M., Sitch, S., Viovy, N., Andreu-Hayles, L., Bednarz, Z., Berninger, F., Boettger, Tatjana, D‘Alessandro, C.M., Daux, V., Filot, M., Grabner, M., Gutierrez, E., Haupt, Marika, Hilasvuori, E., Jungner, H., Kalela-Brundin, M., Krapiec, M., Leuenberger, M., Loader, N.J., Marah, H., Masson-Delmotte, V., Pazdur, A., Pawelczyk, S., Pierre, M., Planells, O., Pukiene, R., Reynolds-Henne, C.E., Rinne, K.T., Saracino, A., Sonninen, E., Stievenard, M., Switsur, V.R., Szczepanek, M., Szychowska-Krapiec, E., Todaro, L., Waterhouse, J.S., Weigl, M., Frank, D.C., Poulter, B., Saurer, M., Esper, J., Huntingford, C., Helle, G., Treydte, K., Zimmermann, N.E., Schleser, G.H., Ahlström, A., Ciais, P., Friedlingstein, P., Levis, S., Lomas, M., Sitch, S., Viovy, N., Andreu-Hayles, L., Bednarz, Z., Berninger, F., Boettger, Tatjana, D‘Alessandro, C.M., Daux, V., Filot, M., Grabner, M., Gutierrez, E., Haupt, Marika, Hilasvuori, E., Jungner, H., Kalela-Brundin, M., Krapiec, M., Leuenberger, M., Loader, N.J., Marah, H., Masson-Delmotte, V., Pazdur, A., Pawelczyk, S., Pierre, M., Planells, O., Pukiene, R., Reynolds-Henne, C.E., Rinne, K.T., Saracino, A., Sonninen, E., Stievenard, M., Switsur, V.R., Szczepanek, M., Szychowska-Krapiec, E., Todaro, L., Waterhouse, J.S., and Weigl, M.

Published
2015

31. Remote Sensing of Water Resources in Semi-Arid Mediterranean Areas: the joint international laboratory TREMA

Author

Jarlan, L., primary, Khabba, S., additional, Er-Raki, S., additional, Le Page, M., additional, Hanich, L., additional, Fakir, Y., additional, Merlin, O., additional, Mangiarotti, S., additional, Gascoin, S., additional, Ezzahar, J., additional, Kharrou, M.H., additional, Berjamy, B., additional, Saaïdi, A., additional, Boudhar, A., additional, Benkaddour, A., additional, Laftouhi, N., additional, Abaoui, J., additional, Tavernier, A., additional, Boulet, G., additional, Simonneaux, V., additional, Driouech, F., additional, El Adnani, M., additional, El Fazziki, A., additional, Amenzou, N., additional, Raibi, F., additional, El Mandour, A., additional, Ibouh, H., additional, Le Dantec, V., additional, Habets, F., additional, Tramblay, Y., additional, Mougenot, B., additional, Leblanc, M., additional, El Faïz, M., additional, Drapeau, L., additional, Coudert, B., additional, Hagolle, O., additional, Filali, N., additional, Belaqziz, S., additional, Marchane, A., additional, Szczypta, C., additional, Toumi, J., additional, Diarra, A., additional, Aouade, G., additional, Hajhouji, Y., additional, Nassah, H., additional, Bigeard, G., additional, Chirouze, J., additional, Boukhari, K., additional, Abourida, A., additional, Richard, B., additional, Fanise, P., additional, Kasbani, M., additional, Chakir, A., additional, Zribi, M., additional, Marah, H., additional, Naimi, A., additional, Mokssit, A., additional, Kerr, Y., additional, and Escadafal, R., additional

Published
2015
Full Text
View/download PDF

32. Water-use efficiency and transpiration across European forests during the Anthropocene

Author

Frank, D. C., primary, Poulter, B., additional, Saurer, M., additional, Esper, J., additional, Huntingford, C., additional, Helle, G., additional, Treydte, K., additional, Zimmermann, N. E., additional, Schleser, G. H., additional, Ahlström, A., additional, Ciais, P., additional, Friedlingstein, P., additional, Levis, S., additional, Lomas, M., additional, Sitch, S., additional, Viovy, N., additional, Andreu-Hayles, L., additional, Bednarz, Z., additional, Berninger, F., additional, Boettger, T., additional, D‘Alessandro, C. M., additional, Daux, V., additional, Filot, M., additional, Grabner, M., additional, Gutierrez, E., additional, Haupt, M., additional, Hilasvuori, E., additional, Jungner, H., additional, Kalela-Brundin, M., additional, Krapiec, M., additional, Leuenberger, M., additional, Loader, N. J., additional, Marah, H., additional, Masson-Delmotte, V., additional, Pazdur, A., additional, Pawelczyk, S., additional, Pierre, M., additional, Planells, O., additional, Pukiene, R., additional, Reynolds-Henne, C. E., additional, Rinne, K. T., additional, Saracino, A., additional, Sonninen, E., additional, Stievenard, M., additional, Switsur, V. R., additional, Szczepanek, M., additional, Szychowska-Krapiec, E., additional, Todaro, L., additional, Waterhouse, J. S., additional, and Weigl, M., additional

Published
2015
Full Text
View/download PDF

33. Isotopic study and relationship between surface and groud waters under a semi-arid climate : case of Souss-Massa basin (South-west of Morocco)

Author

Bouchaou, L., Hsissou, Y., Ikenne, M., Michelot, J.L., Qurtobi, M., Marah, H., Tagma, T., Université Ibn Zohr [Agadir], Département de Géologic, Faculté des sciences, Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), CNESTEN, cnesten, and CRINON, Evelyne

Subjects
[SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2007

34. Application of the 137Cs technique to the estimation of water erosion in the Moulay Bouchta watershed, Western Rif, Morocco

Author

ZOUAGUI, A., BENMANSOUR, M., AMENZOU, N., NOUIRA, A., SABIR, M., BENJELLOUN, H., MARAH, H., BENKADAD, A., ZOUAGUI, A., BENMANSOUR, M., AMENZOU, N., NOUIRA, A., SABIR, M., BENJELLOUN, H., MARAH, H., and BENKADAD, A.

Abstract

Au Maroc, l’érosion hydrique est un processus majeur de dégradation des sols, en particulier dans la zone rifaine, où l’érosion engendre des dégâts importants en amont et en aval des structures hydrauliques, remettant en cause la durabilité de l’exploitation de ces dernières. De même, l’évaluation quantitative de ce processus reste difficile à mettre en oeuvre du fait de la complexité du comportement des particules du sol, aussi bien dans l’espace que dans le temps, en réponse à la diversité et l’interaction des facteurs naturels et anthropiques. C’est ainsi qu’on propose d’évaluer les sédiments déplacés qui sont l’élément perceptible de ce phénomène à travers le suivi du traceur radioactif le Césium 137 (137Cs) caractérisé par son affinité aux particules fines du sol (argile et matière organique). La méthodologie adoptée combine l’utilisation de la technique du 137Cs et les Systèmes d’Information Géographique (SIG), ainsi, on a défini une trentaine d’unités fonctionnelles combinant trois paramètres agro-environnementaux « l’occupation du sol, le type de sol et l’inclinaison de la pente ». Jusqu’à présent, on a échantillonné 9 unités, représentant 68% du bassin versant, deux sites de référence et un prélèvement au niveau de la retenue du barrage pour évaluer le taux de sédimentation. Ensuite, les échantillons ont été analysés par spectrométrie gamma, les activités du 137Cs (Bq/kg), ainsi obtenues, sont converties en taux de perte ou de gain du sol (t/ha/an) à l’aide du modèle masse balance 2 (MBM2) pour les sites perturbés (terrains cultivés) et le modèle de diffusion et migration (DMM) pour les sites non perturbés (forêts et matorrals). Les résultats des pertes en sol à long terme (~ 50 ans) montrent que la majorité des sédiments arrachés (98%) proviennent des terrains cultivés. Ces terrains présentent des taux d’érosion variant de 18 à 36 (t/ha/an), alors que les sites du matorral et de la forêt présentent des taux d’érosion nettement plus faibles, ne dépassant pa

Published
2012

37. Evapotranspiration : processes, sources and environmental implications

Author

Ezzahar, J., Er-Raki, S., Bouarifi, W., Jarlan, L., Marah, H., Khabba, S., Dabdouby, M. E., abdelghani chehbouni, and Er-Raki, S. (ed.)

Subjects
VERGER, EVAPOTRANSPIRATION, ALGORITHME, OPTIMISATION, ETUDE COMPARATIVE, BILAN ENERGETIQUE, OLIVIER, INTERFACE EAU ATMOSPHERE, GENETIQUE, SCINTILLOMETRE, DYNAMIQUE DE VEGETATION, FLUX DE CHALEUR, INTERACTION SOL PLANTE ATMOSPHERE

39. Spatio‐temporal patterns of tree growth as related to carbon isotope fractionation in European forests under changing climate

Author

Michael Grabner, Tatjana Boettger, Sławomira Pawełczyk, Marika Haupt, V. R. Switsur, Adomas Vitas, Christina E. Reynolds-Henne, Michel Stievenard, Marek Krąpiec, Luigi Todaro, Neil J. Loader, Eloni Sonninen, Gerhard H. Schleser, Martin Weigl, Monique Pierre, Katja Rinne-Garmston, David Frank, Matthias Saurer, Isabel Dorado-Liñán, Malgorzata Szymaszek, Laia Andreu-Hayles, Tatiana A. Shestakova, Gerhard Helle, Markus Leuenberger, M. Filot, Hamid Marah, Emmi Hilasvuori, John S. Waterhouse, Kerstin Treydte, Anna Pazdur, Antonio Saracino, Jordi Voltas, Valérie Masson-Delmotte, Jan Esper, Rupert Wimmer, Valérie Daux, Zdzisław Bednarz, Högne Jungner, Octavi Planells, Maarit Kalela‐Brundin, Rūtilė Pukienė, Angelo Rita, Frank Berninger, Emilia Gutiérrez, Elżbieta Szychowska‐Kra̧piec, Shestakova, Ta, Voltas, J, Saurer, M, Berninger, F, Esper, J, Andreu-Hayles, L, Daux, V, Helle, G, Leuenberger, M, Loader, Nj, Masson-Delmotte, V, Saracino, Antonio, Waterhouse, J, Schleser, Gh, Bednarz, Z, Boettger, T, Dorado-Liñán, I, Filot, M, Frank, D, Grabner, M, Haupt, M, Hilasvuori, E, Jungner, H, Kalela-Brundin, M, Krąpiec, M, Marah, H, Pawełczyk, S, Pazdur, A, Pierre, M, Planells, O, Pukienė, R, Reynolds-Henne, Ce, Rinne, Kt, Rita, Angelo, Sonninen, E, Stiévenard, M, Switsur, Vr, Szychowska-Krąpiec, E, Szczepanek, M, Todaro, L, Treydte, K, Vitas, A, Weigl, M, Wimmer, R, Gutiérrez, E, Hickler, T., Rinne‐Garmston , Katja T., The Woods Hole Research Center, Woods Hole Oceanographic Institution (WHOI), Department of Crop and Forest Sciences, School of Agrifood and Forestry Science and Engineering (ETSEA), University of Lleida-Agrotecnio Center (UdL-Agrotecnio), Laboratory of Atmospheric Chemistry [Paul Scherrer Institute] (LAC), Paul Scherrer Institute (PSI), Swiss Federal Institute for Forest, Snow and Landscape Research WSL, Department of Forest Sciences [Helsinki], Faculty of Agriculture and Forestry [Helsinki], University of Helsinki-University of Helsinki, Department of Geography [Mainz], Johannes Gutenberg - Universität Mainz (JGU), Tree‐Ring Laboratory, Lamont–Doherty Earth Observatory of Columbia University, Palisades, New York, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern]-Universität Bern [Bern], Department of Geography [Swansea], Swansea University, University of Naples Federico II, Anglia Ruskin University (ARU), Institut für Bio- und Geowissenschaften [Jülich], Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, Department of Forest Biodiversity, University of Agriculture in Krakow, Department of Isotope Hydrology, Helmholtz Centre for Environmental Research ‒ UFZ, Halle, Germany, Centro de Investigacion Forestal (INIA-CIFOR), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria = National Institute for Agricultural and Food Research and Technology (INIA), School of Geography and Development and Laboratory of Tree-Ring Research, University of Arizona, University of Natural Resources and Life Sciences (BOKU), Laboratory of Chronology, University of Helsinki, Helsinki, Finland, Forestry Museum, Lycksele, Sweden, AGH University of Science and Technology [Krakow, PL] (AGH UST), Laboratoire d'hydrologie isotopique, CNESTEN, Maroc., Chercheur indépendant, Silesian University of Technology, Department of Biological Evolution, Ecology and Environmental Sciences, University of Barcelona, Barcelona, Spain, The State Scientific Research Institute Nature Research Centre, Vilnius, Lithuania, Oeschger Centre for Climate Change Research (OCCR), University of Bern, Soil Ecosystems, Natural Resources Institute Finland (Luke), University of Basilicata, Department of Radioisotopes, Silesian University of Technology, Gliwice, Poland, Environmental Research Centre, Vytautas Magnus University, Kaunas, Lithuania, Holzforschung Austria, University of Natural Resources and Applied Life Sciences, IFA-Tulln, University of Barcelona, Helsingin yliopisto = Helsingfors universitet = University of Helsinki-Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Johannes Gutenberg - Universität Mainz = Johannes Gutenberg University (JGU), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), University of Naples Federico II = Università degli studi di Napoli Federico II, Laboratory of Tree-Ring Research [University of Arizona] (LTRR), Universität für Bodenkultur Wien = University of Natural Resources and Life [Vienne, Autriche] (BOKU), Natural Resources Institute Finland (LUKE), and Università degli studi della Basilicata [Potenza] (UNIBAS)

Subjects
0106 biological sciences, Drought stress, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Climate change, Fractionation, 010603 evolutionary biology, 01 natural sciences, Panoply, Dendroecology, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Isotope fractionation, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, Evapotranspiration, ddc:550, Ecosystem, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Global and Planetary Change, Ecology, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Tree rings, Carbon isotopes, 15. Life on land, [SDE.ES]Environmental Sciences/Environmental and Society, Tree (data structure), [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, 13. Climate action, Isotopes of carbon, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SHS.ENVIR]Humanities and Social Sciences/Environmental studies, Environmental science, carbon isotopes, climate change, dendroecology, drought stress, European forests, latitudinal gradients, Pinus, Quercus, stomatal control, tree rings, European forests
Abstract

Aim The aim was to decipher Europe‐wide spatio‐temporal patterns of forest growth dynamics and their associations with carbon isotope fractionation processes inferred from tree rings as modulated by climate warming. Location Europe and North Africa (30‒70° N, 10° W‒35° E). Time period 1901‒2003. Major taxa studied Temperate and Euro‐Siberian trees. Methods We characterize changes in the relationship between tree growth and carbon isotope fractionation over the 20th century using a European network consisting of 20 site chronologies. Using indexed tree‐ring widths (TRWi), we assess shifts in the temporal coherence of radial growth across sites (synchrony) for five forest ecosystems (Atlantic, boreal, cold continental, Mediterranean and temperate). We also examine whether TRWi shows variable coupling with leaf‐level gas exchange, inferred from indexed carbon isotope discrimination of tree‐ring cellulose (Δ13Ci). Results We find spatial autocorrelation for TRWi and Δ13Ci extending over a maximum of 1,000 km among forest stands. However, growth synchrony is not uniform across Europe, but increases along a latitudinal gradient concurrent with decreasing temperature and evapotranspiration. Latitudinal relationships between TRWi and Δ13Ci (changing from negative to positive southwards) point to drought impairing carbon uptake via stomatal regulation for water saving occurring at forests below 60° N in continental Europe. An increase in forest growth synchrony over the 20th century together with increasingly positive relationships between TRWi and Δ13Ci indicate intensifying impacts of drought on tree performance. These effects are noticeable in drought‐prone biomes (Mediterranean, temperate and cold continental). Main conclusions At the turn of this century, convergence in growth synchrony across European forest ecosystems is coupled with coordinated warming‐induced effects of drought on leaf physiology and tree growth spreading northwards. Such a tendency towards exacerbated moisture‐sensitive growth and physiology could override positive effects of enhanced leaf intercellular CO2 concentrations, possibly resulting in Europe‐wide declines of forest carbon gain in the coming decades. Spanish Government, Grant/Award Number: AGL2015‐68274 ‐C3 ‐3‐R; Sixth Framework Programme, Grant/AwardNumber: EVK2‐2001 ‐00237; Seventh Framework Programme, Grant/AwardNumber: COST ‐STSM ‐ECOST ‐STSM ‐FP1304‐140915‐066395 and ERANET‐Mundus program (Grant agreement 20112573)

Published
2019
Full Text
View/download PDF

40. Water-use efficiency and transpiration across European forests during the Anthropocene

Author

M. Kalela-Brundin, Nicolas Viovy, Benjamin Poulter, Emilia Gutiérrez, Katja T. Rinne, H. Marah, Markus Leuenberger, Kerstin Treydte, Z. Bednarz, Mark R. Lomas, Emmi Hilasvuori, Niklaus E. Zimmermann, Philippe Ciais, John S. Waterhouse, Gerhard H. Schleser, David Frank, Stephen Sitch, Elżbieta Szychowska‐Kra̧piec, Laia Andreu-Hayles, Samuel Levis, Anna Pazdur, Michael Grabner, Tatjana Boettger, Gerhard Helle, Carmela Miriam D’Alessandro, Monique Pierre, Högne Jungner, V. R. Switsur, M. Filot, Matthias Saurer, Eloni Sonninen, Pierre Friedlingstein, Marek Krapiec, M. Szczepanek, C. E. Reynolds-Henne, Octavi Planells, Valérie Daux, Frank Berninger, Chris Huntingford, Luigi Todaro, Anders Ahlström, Valérie Masson-Delmotte, Jan Esper, Sławomira Pawełczyk, Marika Haupt, Neil J. Loader, Martin Weigl, Michel Stievenard, Antonio Saracino, R. Pukiene, Montana State University (MSU), Paul Scherrer Institute (PSI), Swiss Federal Research Institute WSL, SWISS FEDERAL RESEARCH INSTITUTE WSL, Centre for Ecology and Hydrology (CEH), Natural Environment Research Council (NERC), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), ICOS-ATC (ICOS-ATC), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Center for Atmospheric Research [Boulder] (NCAR), Centre for Terrestrial Carbon Dynamics: National Centre for Earth Observation (CTCD), University of Sheffield [Sheffield], College of Life and Environmental Sciences [Exeter], University of Exeter, Modélisation des Surfaces et Interfaces Continentales (MOSAIC), University of Helsinki, Géochrononologie Traceurs Archéométrie (GEOTRAC), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Polish Geological Institute, Climate and Environmental Physics [Bern] (CEP), Physikalisches Institut [Bern], Universität Bern [Bern]-Universität Bern [Bern], CNESTEN, cnesten, inconnu, Inconnu, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Universität Bern [Bern] (UNIBE)-Universität Bern [Bern] (UNIBE), Frank, D. C., Poulter, B., Saurer, M., Esper, J., C., Huntingford, Helle, G., Treydte, K. S., Zimmermann, N. E., G. H., Schleser, A., Ahlström, P., Ciai, P., Friedlingstein, S., Levi, M., Loma, S., Sitch, N., Viovy, Andreu Hayles, L., Bednarz, Z., Berninger, F., Boettger, T., D’Alessandro, C. M., Daux, V., Filot, M., Grabner, M., Gutierrez, E., Haupt, M., Hilasvuori, E., Jungner, H., Kalela Brundin, M., Krapiec, M., Leuenberger, M., Loader, N. J., Marah, H., Masson Delmotte, V., Pazdur, A., Pawelczyk, S., Pierre, M., Planells, O., Pukiene, R., Reynolds Henne, C. E., Rinne, K. T., Saracino, Antonio, Sonninen, E., Stievenard, M., Switsur, V. R., Szczepanek, M., Szychowska Krapiec, E., Todaro, L., Waterhouse, J. S., and Weigl, M.

Subjects
hiilidioksidi, Stomatal conductance, hiili, [SDE.MCG]Environmental Sciences/Global Changes, ta1171, vesi, Growing season, Climate change, Environmental Science (miscellaneous), Atmospheric sciences, tree-ring, chemistry.chemical_compound, hydrologinen kierto, dioxide, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, kasvit, ilmasto, Water cycle, Water-use efficiency, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, climate, CO2 fertilization, ComputingMilieux_MISCELLANEOUS, Transpiration, Hydrology, ilmakehä, atmospheric CO2, elevated CO2, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Global warming, varastointi, 15. Life on land, [SDE.ES]Environmental Sciences/Environmental and Society, gas-exchange, rising CO2, chemistry, 13. Climate action, stomatal conductance, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SHS.ENVIR]Humanities and Social Sciences/Environmental studies, Carbon dioxide, Environmental science, aineiden kierto, Social Sciences (miscellaneous), carbon-isotope discrimination
Abstract

Considering the combined effects of CO2 fertilization and climate change drivers on plant physiology leads to a modest increase in simulated European forest transpiration in spite of the effects of CO2-induced stomatal closure. The Earth’s carbon and hydrologic cycles are intimately coupled by gas exchange through plant stomata1,2,3. However, uncertainties in the magnitude4,5,6 and consequences7,8 of the physiological responses9,10 of plants to elevated CO2 in natural environments hinders modelling of terrestrial water cycling and carbon storage11. Here we use annually resolved long-term δ13C tree-ring measurements across a European forest network to reconstruct the physiologically driven response of intercellular CO2 (Ci) caused by atmospheric CO2 (Ca) trends. When removing meteorological signals from the δ13C measurements, we find that trees across Europe regulated gas exchange so that for one ppmv atmospheric CO2 increase, Ci increased by ∼0.76 ppmv, most consistent with moderate control towards a constant Ci/Ca ratio. This response corresponds to twentieth-century intrinsic water-use efficiency (iWUE) increases of 14 ± 10 and 22 ± 6% at broadleaf and coniferous sites, respectively. An ensemble of process-based global vegetation models shows similar CO2 effects on iWUE trends. Yet, when operating these models with climate drivers reintroduced, despite decreased stomatal opening, 5% increases in European forest transpiration are calculated over the twentieth century. This counterintuitive result arises from lengthened growing seasons, enhanced evaporative demand in a warming climate, and increased leaf area, which together oppose effects of CO2-induced stomatal closure. Our study questions changes to the hydrological cycle, such as reductions in transpiration and air humidity, hypothesized to result from plant responses to anthropogenic emissions.

Published
2015
Full Text
View/download PDF

41. A Functional Schizophrenia-associated genetic variant near the TSNARE1 and ADGRB1 genes.

Author

Wahbeh MH, Boyd RJ, Yovo C, Rike B, McCallion AS, and Avramopoulos D

Abstract

Recent collaborative genome wide association studies (GWAS) have identified >200 independent loci contributing to risk for schizophrenia (SCZ). The genes closest to these loci have diverse functions, supporting the potential involvement of multiple relevant biological processes; yet there is no direct evidence that individual variants are functional or directly linked to specific genes. Nevertheless, overlap with certain epigenetic marks suggest that most GWAS-implicated variants are regulatory. Based on the strength of association with SCZ and the presence of regulatory epigenetic marks, we chose one such variant near TSNARE1 and ADGRB1 , rs4129585, to test for functional potential and assay differences that may drive the pathogenicity of the risk allele. We observed that the variant-containing sequence drives reporter expression in relevant neuronal populations in zebrafish. Next, we introduced each allele into human induced pluripotent cells and differentiated 4 isogenic clones homozygous for the risk allele and 5 clones homozygous for the non-risk allele into neural precursor cells. Employing RNA-seq, we found that the two alleles yield significant transcriptional differences in the expression of 109 genes at FDR <0.05 and 259 genes at FDR <0.1. We demonstrate that these genes are highly interconnected in pathways enriched for synaptic proteins, axon guidance, and regulation of synapse assembly. Exploration of genes near rs4129585 suggests that this variant does not regulate TSNARE1 transcripts, as previously thought, but may regulate the neighboring ADGRB1 , a regulator of synaptogenesis. Our results suggest that rs4129585 is a functional common variant that functions in specific pathways likely involved in SCZ risk., Competing Interests: CONFLICTS OF INTEREST: The authors declare no competing interests.

Published
2023
Full Text
View/download PDF

42. New open-source software for gamma-ray spectra analysis.

Author

El Amri L, Chetaine A, Amsil H, El Mokhtari B, Bounouira H, Didi A, Benchrif A, Laraki K, and Marah H

Abstract

Many commercially available software packages have been created to analyze gamma-ray spectra, but their source code has generally not been shared, although some users may wish to add or modify certain functionality, which is impossible without access to the source code. This study therefore presents a new open-source software package for the analysis of gamma-ray spectra. The name of the software is GSA (Gamma-ray Spectra Analysis), the source code of which is freely available through the GitHub website (https://github.com/LAHCEN-EL-AMRI/Gamma-Spectra-Analysis). The main function of this initial version of the software is to locate peaks, calculate areas, and identify corresponding radionuclides. A future version will complement this by measuring the concentrations of radionuclide elements. The software was validated by comparing its analysis results with those generated by three other software programs, namely Genie 2000, Maestro, and FitzPeaks. All the formulas used are explained in this work, which could be useful for researchers or students looking to create their own software packages for analyzing gamma-ray spectra., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Published
2022
Full Text
View/download PDF

43. Modeling and simulating the induced effect on the steel collimator plug used in the PGAA facility of the Moroccan TRIGA Mark-II reactor under different neutron irradiation levels.

Author

El Mokhtari B, Chetaine A, Amsil H, Embarch K, Benchrif A, Laraki K, and Marah H

Abstract

The main objective of this study is to assess the behavior of the steel collimator plug (steel plug) dedicated to the Prompt Gamma Neutron Activation Analysis (PGAA) facility in the neutron beam tube (NB1) of the 2 MW Moroccan TRIGA Mark-II research reactor. The main function of this steel plug is to reduce the neutron and gamma beam cross section from 15 cm to 5 cm in diameter. This steel plug plays a crucial role in reactor safety because it replaces the original neutron beam plug while also stopping the entire incoming neutron beam. Three aspects were therefore involved in this study, including: i) the released heat induced by both neutron and gamma radiation, ii) the swelling effect caused by both radiation and temperature increases in the steel and iii) the radioactivity induced by neutron radiation in the steel plug. An MCNP6.2 model for the TRIGA Mark-II reactor was used to calculate the neutron spectrum inside the NB1 beam tube at the inlet part of the steel plug. A gamma spectrum of a 900 MW PWR reactor was used as input to account for the gamma radiation's effects on the steel plug. In order to select a convenient steel, two investigations were carried out for two grades of steel, namely mild steel (E235) and 304L stainless steel (SS304L). The results were calculated using an in-house FORTRAN-based program and validated using COMSOL, SPECTER codes, and "Neutron Activation and Scattering Calculator" tools. The results revealed that both the E235 and 304L steels are convenient from a safety point of view, although the E235 steel is preferred at the decommissioning stage., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results