Grass cuticles: a new paleoecological tool for East African lake sediments

1976 ◽  
Vol 54 (15) ◽  
pp. 1725-1734 ◽  
Author(s):  
Patricia G. Palmer
Keyword(s):  
Pollen Grains ◽  
East African ◽  
Tropical Africa ◽  
The Past ◽  
Fossil Material ◽  
Fossil Records ◽  
Many Core ◽  
Source Of Information ◽  
African Lake ◽  
East African Lakes

Reconstruction of past vegetation in grassy environments of tropical Africa is hindered by the indistinguishability of grass pollen grains. For these regions, it is necessary to use other fossil material (e.g. grass leaf fragments) to obtain additional paleoecological data. Since many core samples from East African lakes are rich in cuticular fragments of grasses, the identification of these fragments can provide paleobotanical information to complement pollen studies. Light microscopy and scanning electron microscopy are used to identify fossil cuticles to the level of subfamily, tribe, or genus. This new technique provides a much-needed source of information for reconstructing the past vegetation and past climate of regions where grasses are important elements in the fossil records.

Clay mineral diagenesis in two East African lake sediments

Clay Minerals ◽  
1980 ◽  
Vol 15 (3) ◽  
pp. 291-307 ◽  
Author(s):  
A. Singer ◽  
P. Stoffers
Keyword(s):  
Clay Mineral ◽  
Sediment Cores ◽  
East African ◽  
African Lakes ◽  
The Core ◽  
High Temperature And Pressure ◽  
High K ◽  
Temperature And Pressure ◽  
African Lake ◽  
East African Lakes

AbstractThe vertical clay mineral distribution pattern in two sediment cores taken from two East African lakes has been studied in detail. In the core from Lake Albert (Mobutu Sese Seko) a clay assemblage consisting principally of smectite with some illite and kaolinite in the uppermost segment of the core changed with depth into first a mixed-layer illite-smectite dominated clay and then at 6·60 m into an iltite dominated clay. Lower in the core there was again a transition towards interlayer mixtures, and in the bottom segment towards smectite. These changes are interpreted as a diagenetic transformation of smectite into illite, effected by saline palaeo-lake water with an unusually high K/Na ratio. Three smectite→illite-smectite→illite transition cycles were recognized in a 56 m deep sediment core from Lake Manyara. The sections in which illite dominated contained silt-sized analcime, while those with interlayer mixtures contained alkaline zeolites. The diagenetic illitization of smectite appeared to parallel the process of analcime formation, the K necessary for illitization being released during K,Na-zeolite→analcime transformation. These occurrences suggest that high temperature and pressure may not constitute absolute prerequisites for the diagenetic illitization of smectite.

Prawne regulacje pobierania i transplantacji narządów oraz tkanek w ujęciu europejskiej konwencji bioetycznej

2016 ◽  
pp. 52-65
Author(s):  
Patryk Kołodyński ◽  
Paulina Drab
Keyword(s):  
Ex Vivo ◽  
Legal Aspects ◽  
European Convention ◽  
The Public ◽  
Additional Protocol ◽  
The Past ◽  
Reliable Source ◽  
International Legal Order ◽  
Definition Of ◽  
Source Of Information

Over the past several years, transplantology has become one of the fastest developing areas of medicine. The reason is, first and foremost, a significant improvement of the results of successful transplants. However, much controversy arouse among the public, on both medical and ethical grounds. The article presents the most important concepts and regulations relating to the collection and transplantation of organs and tissues in the context of the European Convention on Bioethics. It analyses the convention and its additional protocol. The article provides the definition of transplantation and distinguishes its types, taking into account the medical criteria for organ transplants. Moreover, authors explained the issue of organ donation ex vivo and ex mortuo. The European Convention on Human Rights and Biomedicine clearly regulates the legal aspects concerning the transplantation and related basic concepts, and therefore provides a reliable source of information about organ transplantation and tissue. This act is a part of the international legal order, which includes the established codification of bioethical standards.

scholarly journals Barriers to identifying and obtaining CME: a national survey of physicians, nurse practitioners and physician assistants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Maureen O’Brien Pott ◽  
Anissa S. Blanshan ◽  
Kelly M. Huneke ◽  
Barbara L. Baasch Thomas ◽  
David A. Cook
Keyword(s):  
Travel Time ◽  
Nurse Practitioners ◽  
Professional Associations ◽  
Physician Assistants ◽  
Age Group ◽  
Sources Of Information ◽  
Online Search ◽  
The Past ◽  
Online Tools ◽  
Source Of Information

Abstract Background CPD educators and CME providers would benefit from further insight regarding barriers and supports in obtaining CME, including sources of information about CME. To address this gap, we sought to explore challenges that clinicians encounter as they seek CME, and time and monetary support allotted for CME. Methods In August 2018, we surveyed licensed US clinicians (physicians, nurse practitioners, and physician assistants), sampling 100 respondents each of family medicine physicians, internal medicine and hospitalist physicians, medicine specialist physicians, nurse practitioners, and physician assistants (1895 invited, 500 [26.3%] responded). The Internet-based questionnaire addressed barriers to obtaining CME, sources of CME information, and time and monetary support for CME. Results The most often-selected barriers were expense (338/500 [68%]) and travel time (N = 286 [57%]). The source of information about CME activities most commonly selected was online search (N = 348 [70%]). Direct email, professional associations, direct mail, and journals were also each selected by > 50% of respondents. Most respondents reported receiving 1–6 days (N = 301 [60%]) and $1000–$5000 (n = 263 [53%]) per year to use in CME activities. Most (> 70%) also reported no change in time or monetary support over the past 24 months. We found few significant differences in responses across clinician type or age group. In open-ended responses, respondents suggested eight ways to enhance CME: optimize location, reduce cost, publicize effectively, offer more courses and content, allow flexibility, ensure accessibility, make content clinically relevant, and encourage application. Conclusions Clinicians report that expense and travel time are the biggest barriers to CME. Time and money support is limited, and not increasing. Online search and email are the most frequently-used sources of information about CME. Those who organize and market CME should explore options that reduce barriers of time and money, and creatively use online tools to publicize new offerings.

Archaeology at the University of Ghana, Legon

1968 ◽  
Vol 11 (03) ◽  
pp. 314-315
Author(s):  
Merrick Posnansky
Keyword(s):  
Iron Age ◽  
Research Work ◽  
Guinea Coast ◽  
The Past ◽  
Volta Basin ◽  
Senior Research ◽  
Extensive Program ◽  
The University ◽  
University Of Ghana ◽  
Source Of Information

In October 1968, the University of Ghana commenced an extensive program in African archaeology. Graduate students from overseas are eligible to enroll for courses at the University, though no scholarships are presently available for non-Ghanaians. The Department of Archaeology of the University of Ghana was established in 1951 under the professorship of A. W. Lawrence. It presently has a senior teaching establishment of four together with a curator and two senior research fellows under the chairmanship of Professor Merrick Posnansky. The Department has a small specialist library, a museum, laboratory, dark room, workshops, and a team of trained technical staff. Most of the Department's research work is normally conducted in the dry season from November to May each year. In the past Professor Oliver Davies, author of the Quaternary of the Guinea Coast (1964) and West Africa before the Europeans (1967), conducted extensive fieldwork relating to the Stone Age and neolithic periods of Ghana's past and made large surface collections from all parts of Ghana which provide a rich topographical source of information on archaeology in Ghana. The Department has conducted extensive excavations in Ghana and its research fellows are presently engaged in writing up the results of the Volta Basin Research Project, in which more than thirty sites have been excavated since 1963 in advance of the formation of a large lake consequent upon the construction of the Volta Dam. The majority of the excavated sites have been of Iron Age date. In September 1968, Mr. C. Flight commenced a new season of excavations at “Neolithic” rock shelter sites at Kintampo, where occupations and burials dated to the middle of the second millennium B.C. were uncovered in 1967. Other excavations conducted during 1968 included work by Mr. D. Calvocoressi at the funerary terracotta site of Ahinsan and by Mr. Duncan Mathewson at the seventeenth-century A.D. Gonja site of Jakpasere. In 1969 a training excavation will be conducted at Elmina on the sixteenth- to eighteenth-century A.D. town in the vicinity of the Portuguese castle.

scholarly journals Neural networks for increased accuracy of allergenic pollen monitoring

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marcel Polling ◽  
Chen Li ◽  
Lu Cao ◽  
Fons Verbeek ◽  
Letty A. de Weger ◽  
...  
Keyword(s):  
Neural Networks ◽  
Airborne Pollen ◽  
Pollen Grains ◽  
Allergenic Pollen ◽  
Herbarium Specimens ◽  
Pollen Monitoring ◽  
Pollen Concentrations ◽  
Source Of Information ◽  
Urticaceae Pollen

AbstractMonitoring of airborne pollen concentrations provides an important source of information for the globally increasing number of hay fever patients. Airborne pollen is traditionally counted under the microscope, but with the latest developments in image recognition methods, automating this process has become feasible. A challenge that persists, however, is that many pollen grains cannot be distinguished beyond the genus or family level using a microscope. Here, we assess the use of Convolutional Neural Networks (CNNs) to increase taxonomic accuracy for airborne pollen. As a case study we use the nettle family (Urticaceae), which contains two main genera (Urtica and Parietaria) common in European landscapes which pollen cannot be separated by trained specialists. While pollen from Urtica species has very low allergenic relevance, pollen from several species of Parietaria is severely allergenic. We collect pollen from both fresh as well as from herbarium specimens and use these without the often used acetolysis step to train the CNN model. The models show that unacetolyzed Urticaceae pollen grains can be distinguished with > 98% accuracy. We then apply our model on before unseen Urticaceae pollen collected from aerobiological samples and show that the genera can be confidently distinguished, despite the more challenging input images that are often overlain by debris. Our method can also be applied to other pollen families in the future and will thus help to make allergenic pollen monitoring more specific.

The Beloved Disciple, the Fourth Evangelist, and the Authorship of the Fourth Gospel

2018 ◽  
Author(s):  
Tom Thatcher
Keyword(s):  
Social Science ◽  
Gospel Of John ◽  
Primary Source ◽  
Fourth Gospel ◽  
The Past ◽  
Historical Individual ◽  
Source Of Information ◽  
Beloved Disciple

Discussions of the authorship of the Gospel of John must answer two questions: who is the Beloved Disciple who is portrayed as the book’s primary source of information, and how is this individual related to the author, John the evangelist? On the first question, scholars are divided on whether the Beloved Disciple is a real historical individual or an ideal symbolic figure. Data from the text itself and from social-science perspectives on the reputations of key figures from the past suggest that both are correct: the Beloved Disciple was a legendary associate of Jesus whose presentation reflects his reputation as a source of information that was critical to the Johannine theological outlook. On the second question, data suggests that the evangelist was not the Beloved Disciple but rather a disciple of that individual, perhaps basing his own book on an earlier document produced by the Beloved Disciple.

Stratigraphic studies of East African lakes

1969 ◽  
Vol 17 (1) ◽  
pp. 147-153 ◽  
Author(s):  
D. A. Livingstone ◽  
R. L. Kendall
Keyword(s):  
East African ◽  
African Lakes ◽  
East African Lakes

scholarly journals The annual International Scientific School on Paleopedology for Young researchers in Siberia: "Paleosols as source of information about past environments" (2010–2019)

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Maria I. Dergacheva ◽  
Alexander O. Makeev
Keyword(s):  
Natural Environment ◽  
Soil Profile ◽  
Loess Soil ◽  
Scientific School ◽  
Soil Series ◽  
Soil Environment ◽  
Altai Region ◽  
The Past ◽  
Source Of Information ◽  
Young Researchers

The article presents information about of the work of the International Scientific School on Paleopedology for Young Researchers. This school was conducted for ten years in Siberia in the Altai region, where unique Pleistocene loess-soil series are common and paleosoil horizons and modern soils are present simultaneously in one and the same soil profile. For ten years leading Russian and foreign scientists gave lectures both on fundamental theoretical and applied issues of paleopedology, as well as on a number of topical issues of related sciences, conducted master classes on the basic methods of field study of paleosols, and young researchers discussed their ideas and results. The article lists the main themes of the lectures/ naming Russian and foreign scientists who read them. It also informs about the monograph “Paleosols, the natural environment and methods for their diagnosis”, based on selected lectures at the School from its start until 2014 and published in Russian. Other selected lectures were published in two languages (Russian and English) in the series “Paleosols – a source of information about the Past environment”. The aricle draws attention to the key site "Volodarka" as being of great importance not only for conducting field master classes, but also as a convenient training ground for scientific research, since there occur various soil environment that can serve as models created by nature itself.

scholarly journals Habent sua fata… ekslibris – informacje o ekslibrisach i ich kolekcjach w „Zbiorach polskich” Edwarda Chwalewika

2019 ◽  
Vol 13 ◽  
pp. 258-272
Author(s):  
Agnieszka Fluda-Krokos
Keyword(s):  
Cultural Heritage ◽  
Cultural Institutions ◽  
Cultural Products ◽  
The Past ◽  
Polish Culture ◽  
Source Of Information ◽  
Source Materials

Edward Chwalewik (1873-1956) is a very important person for Polish culture. He worked many years with books and cultural products and he collected very precious source materials. One of the results of their elaboration is the publication “Polish collections: archives, libraries, offices, galleries, museums and other collections of memorabilia of the past in the homeland and exile” (1916, 1926-1927). The priceless publication is in many cases the only source of information about the once existed collections of cultural heritage. The author, collector and exlibris expert, also included information about provenances. In a few thousand descriptions of various cultural institutions and objects, including the library, recorded ca 300 entries about exlibris – collections and individual signs of books owners. The article presents characteristics of these data and selected examples.

Sign in / Sign up

Export Citation Format

Share Document