12 research outputs found
Radiocarbon investigation of the Superlative African Baobabs from Savé Valley Conservancy, Zimbabwe
Author Posting. © Studia Chemia, 2019. Studia Universitatis Babes-Bolyai Seria Chemia is an Open Access Journal (read, download, copy, distribute, print for research use, search, or link to the full texts of articles). The definitive version was published in Studia Universitatis Babes-Bolyai, Seria Chemia , 64(2), Tom II, (2019): 411-419, doi:10.24193/subbchem.2019.2.35.The article reports the radiocarbon investigation results of the superlative African baobabs from Savé Valley, Zimbabwe. Several wood samples collected from these baobab were analysed by AMS (accelerator mass spectrometry) radiocarbon dating. The radiocarbon dates of the oldest samples were 1529 ± 14 BP for Matendere Big baobab, 1179 ± 19 BP for Chishakwe Big tree and 1096 ± 35 BP for Mokore Giant baobab. The corresponding calibrated ages are 1430 ± 15, 1090 ± 40 and 1020 ± 25 calendar yr. The oldest tree from Savé Valley, which we described previously, is the Humani Bedford Old baobab. The radiocarbon date of its oldest sample, 1655 ± 14 BP, corresponds to a calibrated age of 1580 ± 30 calendar yr.Authors would like to acknowledge Léon and Judy Duplessis, the owners of the Matendere Rach, Lisa-Jane Campbell of Chishakwe Ranch, Roger Whittall, the owner of the Humani Ranch and his wife Anne Whittall, Greg and Melanie Duckworth of Mokore Ranch for granting access in the ranches and for authorising the investigation and sampling of the monumental baobabs. The research was funded by the Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-III-P4-ID-PCE-2016-0776, Nr. 90/2017
Radiocarbon dating of a very large African baobab from Limpopo, South Africa : investigation of the Sagole Big Tree
Author Posting. © Studia Chemia, 2017. This article is posted here by permission of Studia Chemia for personal use, not for redistribution. The definitive version was published in Studia Universitatis Babes-Bolyai, Seria Chemia 62, no. 2, Tom 2 (2017): 355-364, doi:10.24193/subbchem.2017.2.28.The article reports the AMS (accelerator mass spectrometry)
radiocarbon dating results of Sagole Big tree, a giant African baobab from
Limpopo, South Africa. Several wood samples were collected from the walls
of its inner cavity and dated by radiocarbon. The age values along the cavity
samples increase with the distance into the wood. This anomaly shows that
the cavity is a false one. The oldest sample segment had a radiocarbon date
of 781 ± 29 BP, which corresponds to a calibrated age of 740 ± 15 yr. We
estimate that the oldest part of the Sagole baobab has an age of 800-900 yr.
We determined that the tree has a closed ring-shaped structure, which
consists of a large unit with six fused stems and of two additional leaning
stems.The research was funded by the Romanian Ministry of Scientific Research CNCSUEFISCDI
under grant PN-II-ID-PCE-2013-76
Radiocarbon dating of a very old African baobab from Savé Valley, Zimbabwe
Author Posting. © Studia Chemia, 2016. This article is posted here by permission of Studia Chemia for personal use, not for redistribution. The definitive version was published in Studia Chemia 2016, no. 4 (2016): 7-20.The article reports the radiocarbon investigation results of the Humani Bedford baobab, an old African baobab from Savé Valley, Zimbabwe. Two wood samples were collected from the large inner cavity. Several segments were extracted from these samples and analysed by AMS (accelerator mass spectrometry) radiocarbon dating. We found that the age values of segments increase with the distance into the wood. This major anomaly is characteristic to multi-stemmed baobabs with a closed ring-shaped structure and a false cavity inside. The investigation of the Humani Bedford baobab evinced that the baobab consists of three fused stems. The fourth stem of the ring is missing. The oldest dated segment was found to have a radiocarbon date of 1655 ± 14 BP, which corresponds to a calibrated age of 1575 ± 30 yr. The dating results show that the stems which build the ring stopped growing toward the false cavity more than 600 yr ago. By considering the position of the oldest segment in the investigated stem, we concluded that the Humani Bedford baobab is around 1800 yr old. According to our dating results, the Humani Bedford baobab becomes the oldest living African baobab.The research
was funded by the Romanian Ministry of National Education CNCS-UEFISCDI
under grant PN-II-ID-PCE-2013-76
Age and growth rate dynamics of an old African baobab determined by radiocarbon dating
Author Posting. © Arizona Board of Regents on behalf of the University of Arizona, 2010. This article is posted here by permission of Dept. of Geosciences, University of Arizona for personal use, not for redistribution. The definitive version was published in Radiocarbon 52 (2010): 727-734.In 2008, a large African baobab (Adansonia digitata L.) from Makulu Makete, South Africa, split vertically
into 2 sections, revealing a large enclosed cavity. Several wood samples collected from the cavity were processed and radiocarbon
dated by accelerator mass spectrometry (AMS) for determining the age and growth rate dynamics of the tree. The 14C
date of the oldest sample was found to be of 1016 ± 22 BP, which corresponds to a calibrated age of 1000 ± 15 yr. Thus, the
Makulu Makete tree, which eventually collapsed to the ground and died, becomes the second oldest African baobab dated
accurately to at least 1000 yr. The conventional growth rate of the trunk, estimated by the radial increase, declined gradually
over its life cycle. However, the growth rate expressed more adequately by the cross-sectional area increase and by the volume
increase accelerated up to the age of 650 yr and remained almost constant over the past 450 yr.This material is based on work supported by a grant from the Romanian
National University Research Council (PN II - IDEI 2354 Nr. 1092) and by US National Science
Foundation under Cooperative Agreement OCE-022828996
Radiocarbon investigation of the pedunculate oak of Botosana, Romania
Author Posting. © Studia Chemia, 2018. Studia Universitatis Babes-Bolyai Chemia is an Open Access Journal (read, download, copy, distribute, print for research use, search, or link to the full texts of articles). The definitive version was published in Studia Universitatis Babes-Bolyai Chemia 63(4), (2018): 7-13, doi: 10.24193/subbchem.2018.4.01.The article discloses the AMS (accelerator mass spectrometry) radiocarbon dating results of the pedunculate oak of BotoĆana. Four wood samples were extracted from its trunk. Five segments extracted from these samples were analyzed by AMS radiocarbon. Their radiocarbon dates were found to be between 161 ± 21 BP and 260 ± 20 BP. These values correspond to calibrated ages of 235 â 365 years. The dating results extrapolated to the geometric center of the trunk indicate an age of 645 ± 50 years for the oak of BotoĆana.The research was funded by the Romanian Ministry of Research and Innovation CNCS-UEFISCDI under grant PN-III-P4-ID-PCE-2016-0776, Nr. 90/2017
Radiocarbon dating of African baobabs with two false cavities : the investigation of Luna tree
The paper discloses the radiocarbon investigation results of
the Luna tree, a representative African baobab from Venetia Limpopo Nature
Reserve, South Africa. Several wood samples collected from deep incisions
in the trunk were investigated by AMS (accelerator mass spectrometry)
radiocarbon dating. The age sequence of segments extracted from the
oldest sample demonstrates that ages increase with the distance into the
wood up to a point of maximum age, after which ages decrease toward the
sample end. This anomaly is typical for multi-stemmed baobabs, having a
closed ring-shaped structure with a false cavity inside. Dating results reveal
that each of the two large fused units, which build the Luna tree, consist of
such a closed ring. The two closed rings include two interconnected false
inner cavities. False cavities are empty spaces between fused stems that
were never filled with wood. We named this baobab architecture, which has
a very high symmetry, double closed ring-shaped structure with two false
cavities. The new architecture, which is very uncommon, enables baobabs to
reach large sizes and very old ages. The radiocarbon date of the oldest
sample segment was 1507 ± 22 BP, which corresponds to a calibrated age of
1405 ± 20 yr. We estimate that the oldest part of Luna tree has an age of
1600 ± 100 yr. By these results, the Luna tree becomes the fourth oldest
African baobab with accurate dating results.The
Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-IIID-
PCE-2013-76.http://chem.ubbcluj.ro/~studiachemiaam2016Mammal Research InstituteZoology and Entomolog
Tuberculosis impacts multiple aspects in quality of life in a Romanian cohort of drugâsusceptible and drug resistant patients: A patientâreported outcome measures study
Background: Tuberculosis (TB), and especially its drug resistant forms, is responsible for not only significant mortality, but also considerable morbidity, still underâquantified. This study used four PatientâReported Outcome Measures (PROMS) to assess the status of persons affected by drugâsusceptible and drugâresistant TB during their TB treatment or after treatment completion, in Romania, the highest TB burden country in the EU.
Methods: People affected by TB in two different regions in Romania were included during and after treatment, following a crossâsectional design. PROMs used were SFâ36, EQâ5Dâ5L, WPAI and the appâbased audiometry screening tool âuHear.â Descriptive statistics and relevant statistical tests were used to compare groups between themselves and with the general Romanian population.
Results: Both patients with drugâsusceptible and drugâresistant TB experience, with drugâresistant patients experiencing statistically significantly more pain and hearing loss. PROMs show some improvement in the afterâtreatment group; however, compared with the general Romanian population for which data were available, all groups scored lower on all outcome measures.
Conclusion: PROMs offer the possibility of obtaining a more comprehensive view of patients' status, by involving them directly in the medical process and could guide a rehabilitation strategy
The growth stop phenomenon of baobabs (Adansonia spp.) identified by radiocarbon dating
The article reports the growth stop phenomenon, which was documented only for baobabs, i.e. for trees belonging to the Adansonia genus. The identification of growth stop was enabled by radiocarbon dating, which allows a complex investigation of samples collected from the trunk/stems of baobabs. In several cases, the outermost rings of baobabs, which were close to the bark, were found to be old, with ages of several hundreds of years, instead of being very young. Dating results of samples collected from six baobabs are presented. For multistemmed baobabs, the growth stop may occur only for one or several stems. We identified four factors that may induce the growth stop: (i) stress determined by severe climate conditions, (ii) old age, (iii) the need to keep a stable internal architecture, and (iv) the collapse of stems that survive this trauma. Baobabs and their stems affected by growth stop may survive for several centuries, by continuing to produce leaves, flowers, and fruits. This phenomenon was associated with the capacity of baobabs to store large amounts of water in their trunks/stems in the rainy season. This reservoir of water is used during the dry season and allows the trees to survive prolonged drought periods.Selected papers from the 2015 Radiocarbon Conference, Dakar, Senegal, 16â20 November 2015https://www.cambridge.org/core/journals/radiocarbonhj2018Mammal Research Institut
Ammonium salts of organophosphorus acids. Crystal and molecular structure of [Et3NH]+[(SPMe2)(SPPh2)N]- and [2-(O(CH2CH2)2N(H)CH2)C6H4]+[S2P(OPri)2]-
8 pĂĄginas, 4 figuras, 2 tablas, 1 esquema.The ammonium salts [Et3NH]+L- {L- = [(SPMe2)(SPPh2)N]- (1),
Ph2PS2
- (2)} were obtained in the reaction between triethylamine and
the corresponding organophosphorus acid in a 1:1 molar ratio, while
[2-{O(CH2CH2)2N(H)CH2}C6H4]+[S2P(OPri)2]- (3) resulted as hydrolysis product
in the process of growing crystals of [2-{O(CH2CH2)2N(H)CH2}C6H4SeS2P(OPri)2.
Compounds 1 and 2 were characterized by 1H and 31P NMR spectroscopy.
Single-crystal X-ray diffraction studies revealed the presence of short
intermolecular S···H contacts which result in the formation of dimeric units
in 1 and of a layered supramolecular structure in 3.This work was supported by the National University Research Council
of Romania (CNCSIS, Research Project No. ID-2404/2008). A. M. P. thanks
the European Social Fund for a Scholarship (Education and Training Program
2008-2013, POSDRU/6/1.5/S/3).Peer reviewe