2,677 research outputs found
Testing and validating the CERES-wheat (Crop Estimation through Resource and Environment Synthesis-wheat) model in diverse environments
CERES-Wheat is a computer simulation model of the growth, development, and yield of spring and winter wheat. It was designed to be used in any location throughout the world where wheat can be grown. The model is written in Fortran 77, operates on a daily time stop, and runs on a range of computer systems from microcomputers to mainframes. Two versions of the model were developed: one, CERES-Wheat, assumes nitrogen to be nonlimiting; in the other, CERES-Wheat-N, the effects of nitrogen deficiency are simulated. The report provides the comparisons of simulations and measurements of about 350 wheat data sets collected from throughout the world
DISTRIBUTION OF IRON (II) BETWEEN BUFFERED AQUEOUS SOLUTIONS AND CHLOROFORM SOLUTION OF N,NĆ¢ā¬ā¢-ETHYLENEBIS(4-BUTANOYL-2,4-DIHYDRO-5-METHYL-2-PHENYL-3H-PYRAZOL-3-ONEIMINE)
The distribution of Fe(II) between buffered aqueous solution and chloroform solution of N,NĆ¢ā¬ā¢-Ethylenebis(4-butanoyl-2-4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-oneimine)(H2BuEtP) was investigated. The effect of 4-butanoyl-2-4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one(HBuP) in the distribution was also studied. Fe(II) concentration in aqueous raffinate was determined colorimetrically and distribution ratios and percentage extractions calculated by difference from Fe(II) in aqueous phase before and after equilibrations. The optimal pH for Fe(II) distribution slightly lowered to 8.00 in mixed ligands(H2BuEtP/HBuP) organic phase from 8.25 in ligand (H2BuEtP) alone organic phase. The pH range at which quantitative extraction of Fe(II) from aqueous buffered solution into both type of organic phases used for the study was very narrow. The extraction parameters; pH1/2, log D from extraction plots, and log Kex calculated using extraction equations derived from slope analysis showed that the values in both type of organic phases were very close even though mixed ligands(H2BuEtP/HBuP) organic phase values were slightly higher and better. Slope analysis also indicated that the Fe(II) complexes extracted into both organic phases were Fe(BuEtP)o and Fe(HBuEtP)(BuP)o respectively
Heterosis in locally adapted sorghum genotypes and potential of hybrids for increased productivity in contrasting environments in Ethiopia
Increased productivity in sorghum has been achieved in the developed world using hybrids. Despite their yield advantage, introduced hybrids have not been adopted in Ethiopia due to the lack of adaptive traits, their short plant stature and small grain size. This study was conducted to investigate hybrid performance and the magnitude of heterosis of locally adapted genotypes in addition to introduced hybrids in three contrasting environments in Ethiopia. In total, 139 hybrids, derived from introduced seed parents crossed with locally adapted genotypes and introduced R lines, were evaluated. Overall, the hybrids matured earlier than the adapted parents, but had higher grain yield, plant height, grain number and grain weight in all environments. The lowland adapted hybrids displayed a mean better parent heterosis (BPH) of 19%, equating to 1160 kg haā 1 and a 29% mean increase in grain yield, in addition to increased plant height and grain weight, in comparison to the hybrids derived from the introduced R lines. The mean BPH for grain yield for the highland adapted hybrids was 16% in the highland and 52% in the intermediate environment equating to 698 kg haā 1 and 2031 kg haā 1, respectively, in addition to increased grain weight. The magnitude of heterosis observed for each hybrid group was related to the genetic distance between the parental lines. The majority of hybrids also showed superiority over the standard check varieties. In general, hybrids from locally adapted genotypes were superior in grain yield, plant height and grain weight compared to the high parents and introduced hybrids indicating the potential for hybrids to increase productivity while addressing farmers' required traits
Understanding the contribution of target repetition and target expectation to the emergence of the prevalence effect in visual search
Behavior in visual search tasks is influenced by the proportion of trials on which a target is presented (the target prevalence). Previous research has found that when target prevalence is low (2% prevalence), participants tend to miss targets, compared with higher prevalence levels (e.g., 50% prevalence). There is an ongoing debate regarding the relative contribution of target repetition and the expectation that a target will occur in the emergence of prevalence effects. In order to disentangle these two factors, we went beyond previous studies by directly manipulating participantsā expectations regarding how likely a target was to appear on a given trial. This we achieved without using cues or feedback. Our results indicated both target repetition and target expectation contribute to the emergence of the prevalence effect
A SWEET solution to rice blight
Bacterial blight is an important disease of rice that is particularly destructive in Southeast Asia and sub-Saharan Africa, exacerbated by the heavy rains of the monsoon seasons. Estimated crop loss due to bacterial blight may be as high as 75%, with millions of hectares of rice affected annually. In this issue, an international team of researchers describes the use of CRISPR editing to generate rice plants that are broadly resistant to the main pathogen that causes rice blight, Xanthomonas oryzae pv. oryzae (Xoo)1. To enhance the durability and
management of resistance, the team has also developed a kit to trace the disease, and its virulence and resistance alleles2
Does the student-led osteopathy clinical learning environment prepare students for practice?
BACKGROUND: For many allied health disciplines, pre-professional clinical education takes place in student-led, on-campus clinic environments. In these environments, pre-professional students undertake patient care under the supervision of qualified health professionals. Literature exploring the benefits of the student-led clinical learning environment is limited and little is known about the role student-led clinics play in preparing pre-professional osteopathy students for professional practice. AIM: To explore the perceptions of osteopathy clinical educators about the role of the student-led clinic at Victoria University (VU) in preparing pre-professional students for professional practice. METHODS: A qualitative collective case study methodology was utilised to explore clinical educator perceptions. Individual interviews were conducted with clinical educators employed in the university osteopathy clinic. Interview questions were framed around the Capabilities for Osteopathic Practice which set the Australian osteopathy practice standards. Data were assessed by two of the authors using thematic analysis. RESULTS: Nine clinical educators out of 31 employed at the university clinic (29%) agreed to participate. Qualitative analysis generated three themes: perceptions of the student-led clinic (SLC) as a learning environment; clinical educator perception of their role in the SLC; and, challenges to and of the SLC environment. CONCLUSIONS: Clinical educators perceived that the student-led osteopathy clinical learning environment develops pre-professional learners to meet some, but not all, of the capabilities for professional practice as an osteopath in Australia. The environment may be improved through faculty development, fostering a proactive learning approach, addressing system-based issues, and providing opportunities to interact with other health professions
"Go Back to the Land!" Negotiating Space, Framing Governmentality in Lambwe Valley, Kenya 1954-75
Technological perspectives for plant breeding
New Breeding Technologies? For some, both inside and outside
the scientific community, this phrase is synonymous
with gene editingāor used exclusively to describe the
application of CRISPR/Cas9 to plant improvement. Much
as, historically, the term ābiotech cropsā has been hijacked to
only mean crop plants produced using genetic engineering.
However, ābreeding technologiesā refers not only to
genetic modification using techniques of molecular biology,
but also to a vast number of other techniques developed
for breeding via the application of scientific advancements
emanating from disciplines such as computer science, plant
biology, statistics, automation, robotics and artificial intelligence.
This concept is not new: in reality, technology has
been a feature of crop improvement since early in the last
century..
Alteration of Differentiation Potentials by Modulating GATA Transcription Factors in Murine Embryonic Stem Cells
Background. Mouse embryonic stem (ES) cells can be differentiated in vitro by aggregation and/or retinoic acid (RA) treatment. The principal differentiation lineage in vitro is extraembryonic primitive endoderm. Dab2, Laminin, GATA4, GATA5, and GATA6 are expressed in embryonic primitive endoderm and play critical roles in its lineage commitment. Results. We found that in the absence of GATA4 or GATA5, RA-induced primitive endoderm differentiation of ES cells was reduced. GATA4 (ā/ā) ES cells express higher level of GATA5, GATA6, and hepatocyte nuclear factor 4 alpha marker of visceral endoderm lineage. GATA5 (ā/ā) ES cells express higher level of alpha fetoprotein marker of early liver development. GATA6 (ā/ā) ES cells express higher level of GATA5 as well as mesoderm and cardiomyocyte markers which are collagen III alpha-1 and tropomyosin1 alpha. Thus, deletion of GATA6 precluded endoderm differentiation but promoted mesoderm lineages. Conclusions. GATA4, GATA5, and GATA6 each convey a unique gene expression pattern and influences ES cell differentiation. We showed that ES cells can be directed to avoid differentiating into primitive endoderm and to adopt unique lineages in vitro by modulating GATA factors. The finding offers a potential approach to produce desirable cell types from ES cells, useful for regenerative cell therapy
Turning Ideas into Proposals : A Case for Blended Participation During the Participatory Budgeting Trial in Helsinki
Balancing between online-offline stages of participatory procedures is a delicate art that may support or hinder the success of participatory democracy. Participatory budgeting (PB), in particular, is generally rooted in online platforms, but as our case study on the City of Helsinki PB trial suggests, face-to-face events are necessary to engage targeted and often less resourceful actors in the process. Based on a longer-term participant observation, covering the PB process from its early to ideation phase to the current stage of proposal development for the final vote, we argue that the process has thus far been successful in blending online-offline components, largely supported by the active support of borough liaisons who have served as navigators between the different stages. From the point of view of co-creation, different stages of the PB process (ideation, co-creation) call for different strategies of online-offline participation. Effective mobilization of marginalized actors and interactions between public servants and citizens seem to benefit from face-to-face processes, while city-wide voting and discussion can effectively occur in the online platform.Peer reviewe
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