Holocene foraminifera assemblages in the Camau peninsula (Southern Vietnam)

La péninsule de Camau est située au sud du delta du Mekong. les dépôts holocènes sont épais, généralement très argileux et ils contiennent une riche faune de foraminifères benthiques. Les sédiments ont été étudiés dans 24 forages, profonds de 2 à 6 mètres. Environ 70 espèces de foraminifères benthiques ont été inventoriées. Elles ont été regroupées en cinq ensembles correspondant aux cinq paléoenvironements définis dans la région par les auteurs précédents : rivage, côtier agité, côtier calme saumâtre, marais saumâtre, marais salé. L'étude de la répartition horizontale et de la répartition verticale de ces environnements a permis de reconstituer l'évolution paléogéographique de la péninsule pendant l'Holocène. Le trait principal de cette évolution est l'abaissement du niveau marin relatif. Les associations prélevées à une profondeur de 4 mètres indiquent une immersion généralisée de la presqu'île. Les sédiments correspondants ont probablement été déposés durant le maximum de la transgression holocène, quand le niveau marin était de 3 mètres au-dessus du niveau actuel. Par la suite, l'évolution des associations de foraminifères indique une tendance régressive qui correspond : (1) à l'agradation progressive de la péninsule due à l'apport des alluvions; (2) à la régression de l'Holocène terminal. (Résumé d'auteur

Late Holocene Morphodynamic Feedback in Can Gio Mangrove Tide-Dominated River Mouth Systems, Vietnam

Can Gio (CG), a mangrove forest with a dense network of tidal creeks, gradually grew and spread seaward on a coastal platform, which was built since about 8 ka before present (BP). Along with this development, a sand ridge began to form and moved back with the shoreline withdrawal landward in the Late Holocene. This mangrove environment is likely abandoned from the mainland but was, however, the place for settlement of ancient Vietnamese a few centuries BC. The CG mangrove forest was severely destroyed during the American War and was restored since 1980. However, the historical change of the landscape along the Saigon-Dong Nai River (SG-DNR) since the Late Holocene is not completely unraveled. By analyzing sediment cores with a multiproxy approach, we investigated the recent geological development with regard to the variation of the intensity of the East Asian palaeomonsoon and regarding the accommodation space, as both regulate the development of this coastal environment. A recently significant shift in the coastline, mainly due to a change of hydroclimatic factors, was observed. A continuous coastline retreat occurred over the last millennium, changing the depositional environment and reshaping the CG mangrove landscape. Along the present coast and tidal channels, partially strong erosion and bank failures occur, alternating with accretion at other coastal sections. This development tends to increase progressivel

Integrated Cross Sections of the Photo-Neutron Reactions Induced on 197^{197}Au with 60 MeV\text{MeV} Bremsstrahlung

Abstract. Seven photo-neutron reactions 197Au(γ,xn)197-xAu (with x=1-7) produced by the bremsstrahlung end-point energy of 60 MeV were identified. In this work, we focus on the measurement of integrated sections. Experiments were carried out based on the activation method in combination with off-line gamma-ray spectrometric technique. The integrated cross sections of the investigated reactions were determined relative to that of the monitoring reaction 197Au(γ,n)196Au. To validate the experimental results, theoretical predictions were also made using the computer code TALYS 1.9. The current integrated cross-sections of the 197Au(γ,xn)197-xAu reactions with 60 MeV bremsstrahlung end point energy are measured for the first time

Study on spatial distribution of coral reefs in Nam Yet island by using GIS and remote sensing techniques

Research and application of GIS and remote sensing techniques combined with field survey in coastal areas of Nam Yet island had been carried out to establish the distribution map of submarine habitats. Depth-invariant index was used to correct water column’s effects on spectral reflectance of each habitat. The results of satellite image classification showed that area with well-developed coral at great depths accounted for 12%, area with well-developed coral at small depths accounted for 9%, area with poorly-developed coral accounted for 13%, dead coral area accounted for 15% and area of sand, grit, pebbles and weathered coral accounted for 51%. The assessment after classification showed that the overall accuracy of the satellite image interpretation process was 94% and the kappa coefficient was 0.93

Research on marine environment and coral distribution on Nam Yet island using VNRedsat-1 and QuickBird images

Based on the processing of VNRedsat-1 and QuickBird images in the area of Truong Sa archipelago, the research results showed the efficiency of assessing marine environmental characteristics in surroundings of these islands. In this paper, we presented the research results on Nam Yet island and adjacent area. The marine parameters in this research include sea surface temperature (SST) and chlorophyll-a concentration in the surface layer as well as in the deep layers of 20m and 40m, the distributions of the ground objects such as coral shelf, sand accumulation, coral reef combined with seagrass and seaweed. The accuracy of assessment of supervised and unsupervised classified results is approximate of 87.8%. The research results allowed assessing the environmental characteristics, warning of the risk of erosion and coastal line change in the study area

Application of satellite images and VNREDSAT-1 images in study on marine environment in Truong Sa region

The remote sensing images, including images of MODIS, VNREDSAT-1 and altimeter, are applied for researching marine environment with the different resolutions. On the basis of different time remote sensing images, we concentrated on the assessment of several characteristics including the SST, chlorophyll-a concentration and sea surface current at the different depths in different monsoons as well. With the large areas, we used the images of MODIS and altimeter. The detailed research area focuses on the Nam Yet island, and the images of VNREDSAT-1 are used. The analysis method of environmental parameters of SST and chlorophyll-a used the regression functions based on the single and combined bands to enhance the accuracy of the analysis result. The marine parameters collected at different depths in the latest field surveys on Truong Sa archipelago in the years of 2015 and 2018 are presented in this paper. On the basis of these parameters, we can analyse the relationships and compare the real field survey data and corresponding results interpreted from remote sensing images

Study on active tectonic faults using soil radon gas method in Viet Nam

This paper presents the results of soil radon gas measurement in three areas, including Thac Ba and Song Tranh 2 hydropower plants, and the planned locations of the nuclear power plants Ninh Thuan 12 using solid-state nuclear track detectors (SSNTD) with the aim of clarifying the activity of tectonic faults in these areas. The activity of tectonic faults was assessed through radon activity index KRn (the ratio between anomaly and threshold), which was divided into 5 levels as follows ultra-high (KRn 10), high (10≥KRn 5), high (5≥KRn 3), medium (3≥KRn 2) and low (KRn≤2). Soil radon gas measurement results showed that in the radon gas concentrations in the Thac Ba hydropower plant area ranged from 72 Bq/m3 to 273.133 Bq/m3 and maximum radon activity index KRn reached 9.75 (high level). High KRn indexes show Chay River fault active in recent time and the sub-meridian distribution of Rn anomalies suggested a right-slip motion of the fault. Rn concentrations in the Ninh Thuan 12 areas ranged from 6 Bq/m3 to 52.627 Bq/m3, however, the KRn indexes were mostly low (KRn≤3) and the highest value was only 3.42, suggesting that expression of activity of the tectonic faults in this region is not clear, even no expression of fault activity. In the Song Tranh 2 hydropower plant and adjacent areas, radon concentrations ranged from 29 Bq/m3 to 77.729 Bq/m3 and maximum KRn index was 20.16 (ultra-high level). The faults having clearer activity expression are Hung Nhuong - Ta Vy, Song Tra Bong and some high order faults, especially the northwest - southeast segments of these faults or their intersections with the northwest - southeast faults. In addition, the high values KRn in the mentioned intersections can be evidenced for the activeness of northwest - southeast faults at the present time. The studies on active faults using soil radon gas method were performed in areas with very different geological and structural features, but the results are well consistent with the results of previous investigations obtained by other methods. It confirmed the effectiveness and capability of soil radon gas geochemistry applying to study active tectonic faults.ReferencesAl-Hilal M., Al-Ali A., 2010. The role of soil gas radon survey in exploring unknown subsurface faults at Afamia B dam, Syria. Radiat. Meas, 45, 219-224.Amponsah,   P.,   Banoeng-Yakubo,   B.,   Andam,   A., Asiedu, D.,  2008. Soil  radon  concentration along fault systems in parts of south eastern Ghana. J. Afr. Earth Sci. 51, 39-48.Asumadu-Sakyi A.B., Fletcher J.J., Oppon O.C., Qua- shie F.K., Wordson D.A., Adjei C.A., Amartey E.O., Darko E.O. and Amponsah P.,  2011. Preliminary Studies on Geological Fault Location Using Solid State Nuclear Track Detection. Research Journal of Environmental and Earth Sciences, 3(1), 24-31.Baubron, J.-C., Rigo, A., Toutain, J.-P., 2002. Soil gas profiles as a tool to characterize active tectonic are- as: the Jaut Pass example (Pyrenees, France). Earth Planet. Sci. Lett, 196, 69-81.Burton, M., Neri, M., Condarelli, D., 2004. High spatial resolution radon measurements reveal hidden active faults on Mt. Etna. Geophys. Res. Lett, 31, L07618.Ciotoli,  G.,  Etiope,  G.,  Guerra,  M.    Lombardi, S., 1999. The detection of concealed faults in the Ofan- to basin using the correlation between soil gas fracture surveys.   Tectonophysics,  299(3-4), 321-332.Ciotoli, G., Lombardi, S. Annunziatellis, A., 2007. Geostatistical analysis of soil gas data in a high seismic intermontane basin:     Fucino     Plain, central Italy. J. Geophys. Res., 112, B05407, doi:10.1029/2005JB004044.Font, L., Baixeras, C., Moreno, V., Bach, J., 2008. Soil radon levels across the Amer fault. Radiat. Meas, 43, 319-323.Geological and Mineral Resources Map of Viet Nam on 1:200,000, 2005. Published by Department of Geology and Minerals of Viet Nam, Ha Noi, Lists: Yen Bai (F-48-XXI), Tuyen Quang (F-48-XXII), Quang Ngai (D-49-VIIVIII), Hoi An (D-49-I), Da Lat - Cam Ranh (C-49-III).Ghosh D., Deb A. and Sengupta R., 2009. Anomalous radon emission as precursor of earthquake. J. Appl. Geophys., 69, 67-81.González-Díez, A., Soto, J., Gómez-Arozamena, J., Bonachea, J., Martínez-Díaz, J.J., Cuesta, J.A.,Olague, I., Remondo, J., Fernández Maroto, G., Díaz de Terán, J.R., 2009. Identification of latent faults  using  a  radon  test.  Geomorphology,  110,11‐19.Haerudin N, Wahyudi, Munadi S., Suryanto W., 2013. A Soil Gas Radon Survey to Determine Fault at Southern Part of  Rajabasa Geothermal Field, Lampung Indonesia. International Journal of Engineering Technology IJET-IJENS, 13(1), 75-81.Hauksson E., 1981. Radon content of groundwater as an earthquake precursor: evaluation of worldwide data and physical basis. J. Geophys. Res., 86, 9397-9410.Ioannides, K., Papachristodoulou, C., Stamoulis, K., Ka- ramanis, D., Pavlides, S., Chatzipetros, A., Karakala, E., 2003. Soil gas radon: a tool for exploring active fault zones. Appl. Radiat. Isot, 59, 205-213.Israel H. and Bjornsson S., 1967. Radon (Rn-222) and thoron (Rn-220) in soil air over faults. Z. Geophys, 33, 48-64.Kemski, J., Siehl, A., Stegemann, R., Valdivia- Manchego, M., 2001. Mapping the geogenic radon potential in Germany.  Sci.  Total  Environ,  272, 217-230.King  C.Y.,  1978.  Radon emanation on  San  Andreas fault. Nature, 271, 516-519.King, C.Y., King, B.S., Evans, W.C., 1996. Spatial radon anomalies on active faults in California. Appl. Geochem, 11, 497-510.Laskar I., Phukon P., Goswami A.K., Chetry G. and Roy U.C.,   2011.   A possible link between radon anomaly and earthquake. Geochemical Journal, 45, 439-446.Lombardi, S., Voltattorni, N., 2010. Rn, He and CO2 soil gas geochemistry for the study of active and inactive faults. Appl. Geochem, 25, 1206-1220.Moussa M.M., Arabi A-G. M. E., 2003. Soil radon survey for tracing active fault: a case study along Qena- Safaga road, East Desert, Egypt. Radiat. Meas, 37,211-216.Papastefanou C., 2010. Variation of radon flux along active fault zones in association with earthquake occurrence. Radiat. Meas, 45, 943-951.Nguyen Dang Tuc, 2000. Kinematic characteristics of the Red River - Chay River fault zone in Cenozoic.  Journal of  Sciences of the Earth,  22, 174-180 (in Vietnamese).Nguyen Van Pho, Nguyen Trong Yem, 1996. Gas geochemical approach in study of the activity of Red River fault system.  Journal of Geology,  Ha  Noi, series A, 236, 9-10.Nguyen Van Pho, Hoang Tuyet Nga, 1996. Some results of the micro geodynamic maping in Thac Ba area by using of nuclear track detector method. In Geology - Resources, Sci. and Tech. Publishing house, Ha Noi, , 187-191.Nguyen Van Pho, Hoang Thi Tuyet Nga, Doan Thi Thu Tra, 1999. Study on the stability of Thac Ba hy- drpopower dam by using nuclear track detector method. Journal of Geology, Ha Noi, Series B, 13-14, 270-271.Nguyen Van Pho, Hoang Thi Tuyet Nga, Nguyen Trung Minh, Doan Thi Thu Tra, Vu Manh Long, Le Thanh Chung,  Nguyen  Dinh  Xuyen,  Pham  An  Cuong, 2004. Results of radon continuous measurements in soil gas at the North-Western area. Journal of  Sciences of the Earth, 26, 653-656 ( in Vietnamese).Nguyen Trong Yem, 1996. Regimes of tectonic stress field during Cenozoi in Vietnam. Journal of Geology, Ha Noi, series A, 236, 1-6.Reimann C., Filzmoser P., Garrett R.G., 2005. Background and threshold: critical comparison of methods of determination. Science of the Total Environment, 346, 1-3, 1-16.Richon P., Klinger Y., Tapponnier P., Li C.X., Van Der Woerd J., Perrier F., 2010. Measuring radon flux across active faults: Relevance of excavating and possibility of satellite. Radiation Measurements, 45, 211-218.Riggio A., and Santulin M., 2015. Earthquake forecasting: a review of radon as seismic precursor. Bollettino di Geofisica Teorica ed Applicata, 56(2), 95-114.Seminsky K.Zh., Demberel S., 2013. The first estimations of soil-radon activity near faults in Central  Mongolia.  Radiation  Measurements,  49, 19-34.Swakón, J., Kozak, K., Paszkowski, M., Gradzinski, R., Loskiewicz,  J.,  Mazur,  J.,  Janik,  M.,  Bogacz,  J.,Horwacik, T., Olko, P., 2004. Radon concentration in soil gas around local disjunctive tectonic zones in the Krakow area. J. Environ. Radioact, 78, 137-149.Tanner, A.B., 1980. Radon migration in the ground: A supplementary review, in Gesell, T.F., and Lowder, W.M., eds., Natural Radiation Environment III: U.S. Dept. Energy Rept. CONF-780422, 1, 5-56.Toutain J.P., Baubron J.C., 1999. Gas geochemistry and seismotectonics:  a   review.   Tectonophysics  304, 1-27.Tran Trong Hue, 1996. First results of research present geodynamics by soil gas radon method. In Geology - Resource, Ha Noi, 1, 179-185.Tran Trong Hue, 1999. Characteristics of radon radioactive gas in Song Ma fault zone. Journal of Sciences of the Earth, 123-128.Tung S., Leung J. K. C., Jiao J. J., Wiegand J., Wartenberg W., 2013. Assessment of soil radon potential in Hong Kong, China, using a 10-point evaluation system.   Environmental   Earth   Sciences,   68(3), 679-689.Tran Van Duong, Tran Trong Hue, 1996. Some results of the investigation active faults in the South Central Viet  Nam by radon method.  Journal of  Science of the Earth, 18, 276-288.Tran Van Tri, Vu Khuc et al., 2009. Geology and earth resources of Viet Nam. Publishing House for Science and Technology, Ha Noi, 645.Utkin V.I., Yurkov A.K., 2010. Radon as a tracer of tectonic movements. Russian Geology and Geophysics, 51, 220-227.Wakita H., Nakamura Y., Notsu K., Noguchi M. and Asada T., 1980. Radon anomaly: a possible precursor of the 1978 Izu-Oshimakinkai earthquake. Sci., 207, 882-883.Walia V., Mahajan S., Kumar A., Singh S., Singh Bajwa B., Dhar S., Yang T.F., 2008. Fault delineation study using soil gas method in the Dharamsala area, NW Himalayas, India . Radiat. Meas, 43, 337-342.Wang X., Li Y., Du J., Zhou X., 2014. Correlations be- tween radon in soil gas and the activity of seismo- genic faults in the Tangshan area, North China. Ra- diation Measurements, 60, 8-14

Research Trends in Evidence-Based Medicine: A Joinpoint Regression Analysis of More than 50 Years of Publication Data

Background Evidence-based medicine (EBM) has developed as the dominant paradigm of assessment of evidence that is used in clinical practice. Since its development, EBM has been applied to integrate the best available research into diagnosis and treatment with the purpose of improving patient care. In the EBM era, a hierarchy of evidence has been proposed, including various types of research methods, such as meta-analysis (MA), systematic review (SRV), randomized controlled trial (RCT), case report (CR), practice guideline (PGL), and so on. Although there are numerous studies examining the impact and importance of specific cases of EBM in clinical practice, there is a lack of research quantitatively measuring publication trends in the growth and development of EBM. Therefore, a bibliometric analysis was constructed to determine the scientific productivity of EBM research over decades. Methods NCBI PubMed database was used to search, retrieve and classify publications according to research method and year of publication. Joinpoint regression analysis was undertaken to analyze trends in research productivity and the prevalence of individual research methods. Findings Analysis indicates that MA and SRV, which are classified as the highest ranking of evidence in the EBM, accounted for a relatively small but auspicious number of publications. For most research methods, the annual percent change (APC) indicates a consistent increase in publication frequency. MA, SRV and RCT show the highest rate of publication growth in the past twenty years. Only controlled clinical trials (CCT) shows a non-significant reduction in publications over the past ten years. Conclusions Higher quality research methods, such as MA, SRV and RCT, are showing continuous publication growth, which suggests an acknowledgement of the value of these methods. This study provides the first quantitative assessment of research method publication trends in EBM

Holocene foraminifera assemblages in the Camau peninsula (Southern Vietnam)

La péninsule de Camau est située au sud du delta du Mekong. les dépôts holocènes sont épais, généralement très argileux et ils contiennent une riche faune de foraminifères benthiques. Les sédiments ont été étudiés dans 24 forages, profonds de 2 à 6 mètres. Environ 70 espèces de foraminifères benthiques ont été inventoriées. Elles ont été regroupées en cinq ensembles correspondant aux cinq paléoenvironements définis dans la région par les auteurs précédents : rivage, côtier agité, côtier calme saumâtre, marais saumâtre, marais salé. L'étude de la répartition horizontale et de la répartition verticale de ces environnements a permis de reconstituer l'évolution paléogéographique de la péninsule pendant l'Holocène. Le trait principal de cette évolution est l'abaissement du niveau marin relatif. Les associations prélevées à une profondeur de 4 mètres indiquent une immersion généralisée de la presqu'île. Les sédiments correspondants ont probablement été déposés durant le maximum de la transgression holocène, quand le niveau marin était de 3 mètres au-dessus du niveau actuel. Par la suite, l'évolution des associations de foraminifères indique une tendance régressive qui correspond : (1) à l'agradation progressive de la péninsule due à l'apport des alluvions; (2) à la régression de l'Holocène terminal. (Résumé d'auteur

Primary hepatic neuroendocrine tumor

Primary hepatic neuroendocrine tumor (PHNET) is a rare type of neuroendocrine tumor (NET) that is also a primary hepatic tumor. Patients are present with almost no specific clinical symptoms and typically present with negative test results and atypical imaging characteristics; therefore, the differentiation of PHNET from other types of primary hepatic masses can be very difficult. In this article, we describe a case of PHNET that mimicked a liver helminth infection in a 57-year-old man. The diagnosis of PHNET in this patient was challenging, and the final diagnosis was based on imaging, histopathology features, and long-term follow-up