scholarly journals Temporal (1948–2012) and Dynamic Evolution of the Wouri Estuary Coastline within the Gulf of Guinea

2019 ◽  
Vol 7 (10) ◽  
pp. 343 ◽  
Author(s):  
Fotsi ◽  
Pouvreau ◽  
Brenon ◽  
Onguene ◽  
Etame
Keyword(s):  
Morphological Evolution ◽  
Atlantic Coast ◽  
Anthropogenic Pressure ◽  
Gulf Of Guinea ◽  
Time Intervals ◽  
Surveillance Activity ◽  
Sediment Loss ◽  
Downstream Section ◽  
Analysis System ◽  
North Latitude

The Wouri estuary is located in the Gulf of Guinea on the Atlantic coast of Cameroon’s coastline plain (3°49′ and 4°04′ north latitude and 9°20′ to 9°40′ east longitude), and is strongly influenced by coastal dynamics that have remained unquantified over a long period of time. This study analyzed the historical evolution of the Wouri estuarine coastline between 1948 and 2012. Variations in the estuarine evolution of the Wouri were studied from (i) minute topographic extracts from 1948, (ii) 1996–1999 nautical charts, and (iii) 2012 spatial map vectors. The net temporal spatial variation rates were calculated using the statistical methods of the Digital Shoreline Analysis System (DSAS). These change rates were also calculated over two time intervals (1948–1996 and 1996–2012) and over a 64-year period (1948–2012). The study reveals highly disparate results. Indeed, kinematics show that the Wouri estuary was dominated by erosion in its downstream section, with 262.83 ha for –3.2 m/year and 110.56 ha for –5.8 m/year between 1948–1996 and 1996–2012 respectively, and by accretion on the other hand in its upstream section, with 239.17 ha for 4.3 m/year in zone 5 between 1948–1996 and 150.82 ha for 12.6 m/year in zone 4 between 1996–2012. Thus, over the 64-year period (1948–2012), we have a dominance of variation by erosion downstream and conversely by accretion upstream, marked by the presence of amplifying factors (anthropogenic pressure and climate change) of the rate of variation of morphological evolution at the beginning of the 21st century, as compared to the middle-20th century. The observed development of sediment loss and accumulation, both influences and will influence, the sediment regime along the Wouri estuarine coastline. There is a need to develop a systematic sub-regional coastal surveillance activity to effectively manage Cameroon’s coastline system.

scholarly journals First record of Philometra katsuwoni (Nematoda, Philometridae), a parasite of skipjack tuna Katsuwonus pelamis (Perciformes, Scombridae), off South American Atlantic Coast

2009 ◽  
Vol 9 (2) ◽  
pp. 263-266 ◽  
Author(s):  
Melissa Querido Cárdenas ◽  
František Moravec ◽  
Anna Kohn
Keyword(s):  
Coastal Zone ◽  
Atlantic Coast ◽  
Original Description ◽  
First Record ◽  
South American ◽  
Skipjack Tuna ◽  
Gulf Of Guinea ◽  
Katsuwonus Pelamis ◽  
First Time ◽  
Janeiro State

The nematode Philometra katsuwoni Petter & Baudin-Laurencin, 1986, a gonad-infecting parasite of Katsuwonus pelamis (Linneaus 1758), originally described from the Gulf of Guinea, is reported for the first time from the coastal zone of Rio de Janeiro State, Brazil. As compared with the original description, the males of the Brazilian material are generally somewhat larger and their right spicule and the gubernaculum are longer. The subgravid female is described for the first time. It is characterized by the anterior inflation of the esophagus and by the presence of two distinct caudal lobes.

scholarly journals Design of a MATLAB HEC-RAS Interface to Test Advanced Control Strategies on Water Systems

Water ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 763
Author(s):  
Ronan Deshays ◽  
Pablo Segovia ◽  
Eric Duviella
Keyword(s):  
Interface Design ◽  
Control Strategies ◽  
Development Planning ◽  
Hydraulic Systems ◽  
Time Intervals ◽  
Loop Control ◽  
Regular Time ◽  
Advanced Control ◽  
Analysis System ◽  
New Algorithms

The software package HEC-RAS (Hydrologic Engineering Center’s River Analysis System) is widely used by the water engineering community to analyze hydraulic systems and perform development planning. Furthermore, it integrates a control module that allows implementing basic controllers. For more complex approaches, developers from the automatic control and artificial intelligence (AI) communities usually design, implement, and test new algorithms using dedicated software such as MATLAB. However, models of hydraulic systems employed in MATLAB are often very simple. The main objective of the paper is to design a simulation architecture by coupling HEC-RAS with MATLAB, thus improving the accuracy of the dynamics of the hydraulic systems considered in the control simulations. The main feature of the MATLAB HEC-RAS interface design is that it allows one to execute customized code at regular time intervals during the simulation. In this way, closed-loop control and optimization algorithms can be implemented and tested. Moreover, the generic interface allows for any configuration of hydrographical systems. The proposed interface is presented in this paper, and the performance of the approach is demonstrated considering two case studies of different nature.

Fishing, Migrations and Inter-group Relations in the Gulf of Guinea (Atlantic Coast of West Africa) in the Nineteenth and Twentieth Centuries

Itinerario ◽  
2000 ◽  
Vol 24 (1) ◽  
pp. 69-85 ◽  
Author(s):  
Ayodeji Olukoju
Keyword(s):  
Atlantic Coast ◽  
West African ◽  
Gulf Of Guinea ◽  
Population Movements ◽  
Group Relations ◽  
The Past ◽  
The People ◽  
Coastal Belt ◽  
Nineteenth And Twentieth Centuries ◽  
The Republic

The Gulf of Guinea, home to numerous ethnic nationalities, stretches from the Republic of Senegal in the west to Nigeria in the east. There have been population movements and socio-economic interactions within and across the coastal belt over the past millennium. In response to their environment, the people have been engaged in fishing, salt-making, commerce and boat making. Fishing, the pivot of their economy, has taken the leading fishing groups – the Fante and Ewe (Keta) of the Republic of Ghana, and the Izon (Ijaw), Itsekiri and Ilaje of Nigeria – all over the entire West African coastline, where they have established many settlements.

Morphologic evolution of the coccolithophorid Calcidiscus leptoporus from the Early Miocene to Recent

2000 ◽  
Vol 74 (4) ◽  
pp. 712-730 ◽  
Author(s):  
Michael Knappertsbusch
Keyword(s):  
Late Miocene ◽  
Morphological Evolution ◽  
Early Miocene ◽  
Time Intervals ◽  
Separate Species ◽  
Similar Morphology ◽  
The Past ◽  
Extant Species ◽  
Morphologic Evolution ◽  
Phylogenetic Model

A detailed investigation of the morphological evolution of the coccolithophorids Calcidiscus leptoporus and C. macintyrei from the Early Miocene to the Quaternary shows that microevolutionary patterns were very complex. Speciation patterns such as cladogenesis and phyletic divergence were observed, but stasis also existed over prolonged time-intervals. Similar coccoliths developed repeatedly at stratigraphically distant intervals, leading to taxonomic uncertainies. On the basis of bivariate frequency diagrams of coccolith diameters and number of elements in the distal shields nine morphotypes S, I, L, F, A, B, C, D and E are distinguished. A tentative phylogeny was constructed for these morphotypes suggesting, that they belong to one extant species and several extinct species. The extant species is Calcidiscus leptoporus, which comprises the living morphotypes S, I, L, and F and one extinct morphotype E. Morphotype S is the most conservative one, which originated from an unknown ancestor during the Early Miocene or earlier, while morphotype I originated from S during the Early Miocene. Morphotypes L and E separated from I during the Late Miocene. An extinct lineage is proposed, including morphotypes C, D, A, and B, which all produced large coccoliths except morphotype B, which is small. Morphotypes C, D, and A are very similar to a coccolith that specialists call Calcidiscus macintyrei, but in the present phylogenetic model they may belong to separate species with similar morphology. Morphotype C developed from morphotype I during the Early Miocene and is the precursor of an extra large morphotype D, and two other morphotypes, A and B. All three forms separated from morphotype C by pronounced cladogenetic events during the Late Miocene and Pliocene, and hence may represent separate species. Morphotypes A and B are supposed to belong to an extinct morphocline and may thus be ecophenotypes of one species. Alternatively, due to the lack of paleoenvironmental and biogeographic observations in the past, it cannot be discounted that all morphotypes found in this investigation simply represent ecovariants of one species. With the present status of knowledge, it is not possible to propose a sound differential diagnosis in the plexus C. leptoporus-C. macintyrei, which would allow differentiation among species at each point in space and time. It is hoped that this study stimulates further morphometric and phylogenetical studies that will generate a more profound understanding of species in paleontology and biology in general.

Rotational Characteristics of the Green Solar Corona: 1947-1991

1994 ◽  
Vol 144 ◽  
pp. 139-141 ◽  
Author(s):  
J. Rybák ◽  
V. Rušin ◽  
M. Rybanský
Keyword(s):  
Solar Corona ◽  
World Wide ◽  
Rotation Period ◽  
Original Data ◽  
Coronal Emission ◽  
Time Intervals ◽  
Data Set ◽  
The World ◽  
Coronal Emission Line ◽  
Homogeneous Data

AbstractFe XIV 530.3 nm coronal emission line observations have been used for the estimation of the green solar corona rotation. A homogeneous data set, created from measurements of the world-wide coronagraphic network, has been examined with a help of correlation analysis to reveal the averaged synodic rotation period as a function of latitude and time over the epoch from 1947 to 1991.The values of the synodic rotation period obtained for this epoch for the whole range of latitudes and a latitude band ±30° are 27.52±0.12 days and 26.95±0.21 days, resp. A differential rotation of green solar corona, with local period maxima around ±60° and minimum of the rotation period at the equator, was confirmed. No clear cyclic variation of the rotation has been found for examinated epoch but some monotonic trends for some time intervals are presented.A detailed investigation of the original data and their correlation functions has shown that an existence of sufficiently reliable tracers is not evident for the whole set of examinated data. This should be taken into account in future more precise estimations of the green corona rotation period.

Automated Image Analysis Of Nuclear And Cytoplasmic Changes In Exfoliated Cells From Tracheas Treated With Carcinogen

1977 ◽  
Vol 35 ◽  
pp. 220-221
Author(s):  
S.F. Stinson ◽  
J.C. Lilga ◽  
M.B. Sporn
Keyword(s):  
Image Analysis ◽  
Pattern Analysis ◽  
Relative Proportion ◽  
Automated Image Analysis ◽  
Image Analyzer ◽  
Cross Sectional ◽  
Exfoliated Cells ◽  
Neoplastic Lesions ◽  
Analysis System ◽  
Morphologic Criterion

Increased nuclear size, resulting in an increase in the relative proportion of nuclear to cytoplasmic sizes, is an important morphologic criterion for the evaluation of neoplastic and pre-neoplastic cells. This paper describes investigations into the suitability of automated image analysis for quantitating changes in nuclear and cytoplasmic cross-sectional areas in exfoliated cells from tracheas treated with carcinogen.Neoplastic and pre-neoplastic lesions were induced in the tracheas of Syrian hamsters with the carcinogen N-methyl-N-nitrosourea. Cytology samples were collected intra-tracheally with a specially designed catheter (1) and stained by a modified Papanicolaou technique. Three cytology specimens were selected from animals with normal tracheas, 3 from animals with dysplastic changes, and 3 from animals with epidermoid carcinoma. One hundred randomly selected cells on each slide were analyzed with a Bausch and Lomb Pattern Analysis System automated image analyzer.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

Digital Processing of STEM Images

1981 ◽  
Vol 39 ◽  
pp. 236-237
Author(s):  
A. V. Crewe ◽  
M. Ohtsuki
Keyword(s):  
High Resolution ◽  
Low Dose ◽  
Assembly Language ◽  
Processing System ◽  
Principal Component ◽  
Digital Processing ◽  
Image Analysis System ◽  
Black And White ◽  
Analysis System ◽  
Dose Imaging

We have assembled an image processing system for use with our high resolution STEM for the particular purpose of working with low dose images of biological specimens. The system is quite flexible, however, and can be used for a wide variety of images.The original images are stored on magnetic tape at the microscope using the digitized signals from the detectors. For low dose imaging, these are “first scan” exposures using an automatic montage system. One Nova minicomputer and one tape drive are dedicated to this task.The principal component of the image analysis system is a Lexidata 3400 frame store memory. This memory is arranged in a 640 x 512 x 16 bit configuration. Images are displayed simultaneously on two high resolution monitors, one color and one black and white. Interaction with the memory is obtained using a Nova 4 (32K) computer and a trackball and switch unit provided by Lexidata.The language used is BASIC and uses a variety of assembly language Calls, some provided by Lexidata, but the majority written by students (D. Kopf and N. Townes).

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