160 research outputs found
Meiotic behaviour of Eragrostis tef and,i> Eragrostis Pilosa
Tef (Eragrostis tef (Zucc.) Trotter) is major cereal crop cultivated in Ethiopia. It occupies approximately two million hectares of land each year. However, little has been done on meiotic chromosome study of the interspes hybrid. So, studies were conducted to examine meiotic behavior and pollen fertility of the F1-hybrid (E. tef x E. pilosa) and parental lines at Addis Ababa, Ethiopia in 200 7/08. The F1-hybrid plant showed regular meiotic cell division and high level of pollen fertility (94.3%). It also produced better seed and biomass yield and number of tillers than the parental lines which are the manifestation of meiotic stability in the hybrid and the subsequent generations. Pollen fertility test of the parental lines and selected recombinant inbred lines of E. tef and E. pilosa cross was also high (90 - 95%), which are an indication of regular meiotic chromosome division. The resultdemonstrated chromosome stability of the hybrid plant, which is important for widening the genetic pool of tef germplasm through conventional crossing with E. pilosa. The study further strengthen the view that the two species are very closely related
The OmegaWhite Survey for Short-Period Variable Stars IV: Discovery of the warm DQ white dwarf OW J175358.85-310728.9
We present the discovery and follow-up observations of the second known
variable warm DQ white dwarf OW J175358.85-310728.9 (OW J1753-3107). OW
J1753-3107 is the brightest of any of the currently known warm or hot DQ and
was discovered in the OmegaWhite Survey as exhibiting optical variations on a
period of 35.5452 (2) mins, with no evidence for other periods in its light
curves. This period has remained constant over the last two years and a
single-period sinusoidal model provides a good fit for all follow-up light
curves. The spectrum consists of a very blue continuum with strong absorption
lines of neutral and ionised carbon, a broad He I 4471 A line, and possibly
weaker hydrogen lines. The C I lines are Zeeman split, and indicate the
presence of a strong magnetic field. Using spectral Paschen-Back model
descriptions, we determine that OW J1753-3107 exhibits the following physical
parameters: T_eff = 15430 K, log(g) = 9.0, log(N(C)/N(He)) = -1.2, and the mean
magnetic field strength is B_z =2.1 MG. This relatively low temperature and
carbon abundance (compared to the expected properties of hot DQs) is similar to
that seen in the other warm DQ SDSS J1036+6522. Although OW J1753-3107 appears
to be a twin of SDSS J1036+6522, it exhibits a modulation on a period slightly
longer than the dominant period in SDSS J1036+6522 and has a higher carbon
abundance. The source of variations is uncertain, but they are believed to
originate from the rotation of the magnetic white dwarf.Comment: 11 pages, 8 figures, 7 tables. Accepted for publication by MNRA
Integrating phenotypic evaluations with a molecular diversity assessment of an Ethiopian collection of common bean landraces
Understanding the organisation of genetic diversity in a crop species
is a key element for both the conservation and utilisation of its
genetic resources. In the case of common bean ( Phaseolus vulgaris
L.), Ethiopia is one of the secondary centers of diversity of this
species. Hence, this study sought to improve our understanding of
genetic diversity of common bean by integrating morphological and
agronomic evaluations with prior molecular diversity data from a
collection of landrace accessions from different common bean growing
regions of Ethiopia. The samples studied included 115 landraces, four
standard varieties, and two control genotypes. Twenty agronomic traits
and morphological descriptors were used to evaluate the accessions
under field conditions. A Principal Component Analysis clearly
separated the accessions into the Andean and Mesoamerican gene pools,
with the first two axes explaining most of the variation. Step-wise
discriminant and canonical correlation analyses, with all variables or
only the morphological variables, enabled the identification of
characters distinguishing accessions from the Andean/Mesoamerican gene
pools, and their respective ecogeographic races. Data distinguishing
racial and morphological traits were used to clarify the identities of
five cluster groups, identified at STRUCTURE preset K = 5, in a
preceding study. The three Andean cluster groups were shown to belong
to two of the races in the gene pool, \u2018Nueva Granada\u2019 and
\u2018Peru\u2019; while the two Mesoamerican groups were from the
race \u2018Mesoamerica\u2019. By integrating the morphological and
agronomic evaluation of an Ethiopian germplasm collection of common
bean, initially performed just based on molecular characterisation, we
were able to improve our understanding of the organisation of this
diversity. Our results suggest extensive hybridisation between the
Andean and Mesoamerican gene pools after introduction of common bean
germplasm in Ethiopia.Connaitre l\u2019organisation de la diversit\ue9 g\ue9n\ue9tique
sur une culture est un \ue9l\ue9ment important \ue0 la fois pour
la conservation et l\u2019utilisation de ses ressources
g\ue9n\ue9tiques. Dans le cas du haricot commun ( Phaseolus
vulgaris L), l\u2019Ethiopie est l\u2019un des centres secondaires
de la diversit\ue9 de l\u2019esp\ue8ce. Par cons\ue9quent, cette
\ue9tude cherche \ue0 am\ue9liorer notre compr\ue9hension de la
diversit\ue9 g\ue9n\ue9tique du haricot commun en int\ue9grant
les \ue9valuations morphologique et agronomiques avec une
\ue9valuation pr\ue9alable de la diversit\ue9 mol\ue9culaire
d\u2019une collection de cultivars traditionnels venus de
diff\ue9rentes r\ue9gions productrices du haricot commun de
l\u2019Ethiopie. Les \ue9chantillons utilis\ue9s comprennent 115
cultivars traditionnels, quatre vari\ue9t\ue9s standards, et deux
g\ue9notypes contr\uf4les. Vingt traits descripteurs agronomiques
et morphologiques \ue9taientutilis\ue9s pour \ue9valuer les
accessions dans des conditions de champ. Une analyse en composante
principale a clairement s\ue9par\ue9 les accessions en des pools de
g\ue8nes Andins et M\ue9soam\ue9ricains avec les deux premiers
axes expliquant la plus grande variation. Les analyses discriminante
par \ue9tapes la corr\ue9lation canonique, avec toutes les
variables ou seule avec les variables morphologiques, ont permis
l\u2019identification des caract\ue8res discriminant les accessions
des pools de g\ue8nes Andins et M\ue9soam\ue9ricains, et leurs
races Eco g\ue9ographiques respectives. Les donn\ue9es discriminant
les traits raciaux et morphologiques \ue9taient utilis\ue9s pour
clarifier les identit\ue9s des cinq classes, identifi\ue9es \ue0
la configuration pr\ue9finie K= 5, dans l\u2019\ue9tude
pr\ue9c\ue9dente. Les trois groupes de classes Andines
appartiennent \ue0 deux races dans le pool de g\ue8nes,
\u2018Nueva Granada\u2019 et \u2018Peru\u2019\ua0; alors que les
groupes M\ue9soam\ue9ricains \ue9taient de la race
\u2018M\ue9soam\ue9rica\u2019. En int\ue9grant
l\u2019\ue9valuation morphologique et agronomique de la collection
du germoplasm du haricot commun Ethiopien, initialement conduit juste
sur la base de la caract\ue9risation mol\ue9culaire, nous avions pu
am\ue9liorer notrecompr\ue9hension de l\u2019organisation de cette
diversit\ue9. Nos r\ue9sultats sugg\ue8rent une hybridation
extensive entre les pools de g\ue8nes Andins et
M\ue9soam\ue9ricains apr\ue8s une introduction du germoplasm du
haricot commun de l\u2019Ethiopie
Phytochemical investigations of three Rhodocodon (Hyacinthaceae Sensu APG II) species
The genus Rhodocodon (Hyacinthaceae sensu APG II) is endemic to Madagascar and its phytochemistry has not been described previously. The phytochemistry of three species in this genus has been investigated and eight compounds, including three bufadienolides (compounds 1, 4, and 5), a norlignan (2), and four homoisoflavonoids (compounds 3 and 6-8) have been isolated and identified. Compounds 1-3 and 6-8 have not been described previously. The COX-2 inhibitory activity of compound 6 and compound 7 acetate (compound 7A) were investigated on isolated colorectal cancer cells. Compounds 6 and 7A inhibited COX-2 by 10% and 8%, respectively, at a concentration of 12.5 M compared to 12% for 1 mM aspirin (the positive control)
Evaluation of the diagnostic performance of MTBDRplus VER 2.0 line probe assay for the detection of MDR-TB in sputum samples referred to National TB Reference Laboratory, Ethiopian Public Health Institute
Global, regional, and national burden of diabetes from 1990 to 2021, with projections of prevalence to 2050:a systematic analysis for the Global Burden of Disease Study 2021
Background: Diabetes is one of the leading causes of death and disability worldwide, and affects people regardless of country, age group, or sex. Using the most recent evidentiary and analytical framework from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD), we produced location-specific, age-specific, and sex-specific estimates of diabetes prevalence and burden from 1990 to 2021, the proportion of type 1 and type 2 diabetes in 2021, the proportion of the type 2 diabetes burden attributable to selected risk factors, and projections of diabetes prevalence through 2050. Methods: Estimates of diabetes prevalence and burden were computed in 204 countries and territories, across 25 age groups, for males and females separately and combined; these estimates comprised lost years of healthy life, measured in disability-adjusted life-years (DALYs; defined as the sum of years of life lost [YLLs] and years lived with disability [YLDs]). We used the Cause of Death Ensemble model (CODEm) approach to estimate deaths due to diabetes, incorporating 25 666 location-years of data from vital registration and verbal autopsy reports in separate total (including both type 1 and type 2 diabetes) and type-specific models. Other forms of diabetes, including gestational and monogenic diabetes, were not explicitly modelled. Total and type 1 diabetes prevalence was estimated by use of a Bayesian meta-regression modelling tool, DisMod-MR 2.1, to analyse 1527 location-years of data from the scientific literature, survey microdata, and insurance claims; type 2 diabetes estimates were computed by subtracting type 1 diabetes from total estimates. Mortality and prevalence estimates, along with standard life expectancy and disability weights, were used to calculate YLLs, YLDs, and DALYs. When appropriate, we extrapolated estimates to a hypothetical population with a standardised age structure to allow comparison in populations with different age structures. We used the comparative risk assessment framework to estimate the risk-attributable type 2 diabetes burden for 16 risk factors falling under risk categories including environmental and occupational factors, tobacco use, high alcohol use, high body-mass index (BMI), dietary factors, and low physical activity. Using a regression framework, we forecast type 1 and type 2 diabetes prevalence through 2050 with Socio-demographic Index (SDI) and high BMI as predictors, respectively. Findings: In 2021, there were 529 million (95% uncertainty interval [UI] 500–564) people living with diabetes worldwide, and the global age-standardised total diabetes prevalence was 6·1% (5·8–6·5). At the super-region level, the highest age-standardised rates were observed in north Africa and the Middle East (9·3% [8·7–9·9]) and, at the regional level, in Oceania (12·3% [11·5–13·0]). Nationally, Qatar had the world's highest age-specific prevalence of diabetes, at 76·1% (73·1–79·5) in individuals aged 75–79 years. Total diabetes prevalence—especially among older adults—primarily reflects type 2 diabetes, which in 2021 accounted for 96·0% (95·1–96·8) of diabetes cases and 95·4% (94·9–95·9) of diabetes DALYs worldwide. In 2021, 52·2% (25·5–71·8) of global type 2 diabetes DALYs were attributable to high BMI. The contribution of high BMI to type 2 diabetes DALYs rose by 24·3% (18·5–30·4) worldwide between 1990 and 2021. By 2050, more than 1·31 billion (1·22–1·39) people are projected to have diabetes, with expected age-standardised total diabetes prevalence rates greater than 10% in two super-regions: 16·8% (16·1–17·6) in north Africa and the Middle East and 11·3% (10·8–11·9) in Latin America and Caribbean. By 2050, 89 (43·6%) of 204 countries and territories will have an age-standardised rate greater than 10%. Interpretation: Diabetes remains a substantial public health issue. Type 2 diabetes, which makes up the bulk of diabetes cases, is largely preventable and, in some cases, potentially reversible if identified and managed early in the disease course. However, all evidence indicates that diabetes prevalence is increasing worldwide, primarily due to a rise in obesity caused by multiple factors. Preventing and controlling type 2 diabetes remains an ongoing challenge. It is essential to better understand disparities in risk factor profiles and diabetes burden across populations, to inform strategies to successfully control diabetes risk factors within the context of multiple and complex drivers. Funding: Bill & Melinda Gates Foundation.</p
The state of the Martian climate
60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes
Factors that transformed maize productivity in Ethiopia
Published online: 26 July 2015Maize became increasingly important in the food
security of Ethiopia following the major drought and famine
that occurred in 1984. More than 9 million smallholder house-
holds, more than for any other crop in the country, grow maize
in Ethiopia at present. Ethiopia has doubled its maize produc-
tivity and production in less than two decades. The yield,
currently estimated at >3 metric tons/ha, is the second highest
in Sub-Saharan Africa, after South Africa; yield gains for
Ethiopia grew at an annual rate of 68 kg/ha between 1990
and 2013, only second to South Africa and greater than
Mexico, China, or India. The maize area covered by improved
varieties in Ethiopia grew from 14 % in 2004 to 40 % in 2013,
and the application rate of mineral fertilizers from 16 to 34 kg/
ha during the same period. Ethiopia
’
s extension worker to
farmer ratio is 1:476, compared to 1:1000 for Kenya, 1:1603
for Malawi and 1:2500 for Tanzania. Increased use of im-
proved maize varieties and mineral fertilizers, coupled with
increased extension services and the absence of devastating
droughts are the key factors promoting the accelerated growth
in maize productivity in Ethiopia. Ethiopia took a homegrown
solutions approach to the research and development of its
maize and other commodities. The lesson from Ethiopia
’
s
experience with maize is that sustained investment in agricul-
tural research and development and policy support by the
national government are crucial for continued growth of
agricultur
Knowledge, attitudes and practice of communities of Wolaita, Southern Ethiopia about long-lasting insecticidal nets and evaluation of net fabric integrity and insecticidal activity
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