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2.
Sci Rep ; 9(1): 4226, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30862936

RESUMO

Remains of the freshwater fern Azolla, found in Eocene (~50 Ma ago) sediments in the modern central Arctic Ocean, have been used to suggest that seasonal freshwater caps covered the entire Arctic Ocean during that time, with significant impact on global ocean circulation and climate. However, these records are located on the Lomonosov Ridge, which during the Eocene was a continental fragment barely rifted from Eurasia, separating the smaller Eurasian Basin from the much larger Amerasian Basin to the west. As such, the Lomonosov Ridge does not necessarily record environmental conditions of the broader Arctic Ocean. We tested the hypothesis of freshwater caps by examining sediment records from the western Amerasian Basin. Here we show that in the larger Amerasian Basin the Azolla event is associated with marine microfauna along with allochthonous (terrestrially sourced) organic matter. We propose that Azolla events are related to an increased hydrologic cycle washing terrestrially sourced Azolla, and other organics, into the Arctic Ocean. If freshwater caps did occur, then they were at best restricted to the small Eurasian Basin and would have had a limited impact on Eocene global climate, contrary to current models.

3.
Front Plant Sci ; 8: 136, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28223998

RESUMO

The annual Zea mays ssp. mexicana L. is a member of teosinte, a wild relative of the Zea mays spp. mays L. This subspecies has strong growth and regeneration ability, high tiller numbers, high protein and lysine content as well as resistance to many fungal diseases, and it can be effectively used in maize improvement. In this study, we reported a Zea mays ssp. mexicana L. transcriptome by merging data from untreated control (CK), cold (4°C) and drought (PEG2000, 20%) treated plant samples. A total of 251,145 transcripts (N50 = 1,269 bp) and 184,280 unigenes (N50 = 923 bp) were predicted, which code for homologs of near 47% of the published maize proteome. Under cold conditions, 2,232 and 817 genes were up-regulated and down-regulated, respectively, while fewer genes were up-regulated (532) and down-regulated (82) under drought stress, indicating that Zea mays ssp. mexicana L. is more sensitive to the applied cold rather than to the applied drought stresses. Functional enrichment analyses identified many common or specific biological processes and gene sets in response to drought and cold stresses. The ABA dependent pathway, trehalose synthetic pathway and the ICE1-CBF pathway were up-regulated by both stresses. GA associated genes have been shown to differentially regulate the responses to cold in close subspecies in Zea mays. These findings and the identified functional genes can provide useful clues for improving abiotic stress tolerance of maize.

4.
Plant Physiol Biochem ; 113: 78-88, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-28189052

RESUMO

The annual Zea mays ssp. mexicana L., a member of the teosinte group, is a close wild relative of maize and thus can be effectively used in maize improvement. In this study, an ICE-like gene, ZmmICE1, was isolated from a cDNA library of RNA-Seq from cold-treated seedling tissues of Zea mays ssp. mexicana L. The deduced protein of ZmmICE1 contains a highly conserved basic helix-loop-helix (bHLH) domain and C-terminal region of ICE-like proteins. The ZmmICE1 protein localizes to the nucleus and shows sumoylation when expressed in an Escherichia coli reconstitution system. In addition, yeast one hybrid assays indicated that ZmmICE1 has transactivation activities. Moreover, ectopic expression of ZmmICE1 in the Arabidopsis ice1-2 mutant increased freezing tolerance. The ZmmICE1 overexpressed plants showed lower electrolyte leakage (EL), reduced contents of malondialdehyde (MDA). The expression of downstream cold related genes of Arabidopsis C-repeat-binding factors (AtCBF1, AtCBF2 and AtCBF3), cold-responsive genes (AtCOR15A and AtCOR47), kinesin-1 member gene (AtKIN1) and responsive to desiccation gene (AtRD29A) was significantly induced when compared with wild type under low temperature treatment. Taken together, these results indicated that ZmmICE1 is the homolog of Arabidopsis inducer of CBF expression genes (AtICE1/2) and plays an important role in the regulation of freezing stress response.


Assuntos
Adaptação Fisiológica/genética , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/genética , Zea mays/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/biossíntese , Proteínas de Arabidopsis/metabolismo , Sequência de Bases , Temperatura Baixa , Congelamento , Malondialdeído/metabolismo , Plantas Geneticamente Modificadas , Prolina/biossíntese , Prolina/genética , RNA de Plantas/genética , Estresse Fisiológico/genética , Sumoilação/genética , Fatores de Transcrição/biossíntese , Fatores de Transcrição/metabolismo , Zea mays/metabolismo
5.
Healthc Q ; 19(2): 67-72, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27700977

RESUMO

The transition from hospital to home is a vulnerable period for patients with complex conditions, who are often frail, at risk for adverse events and unable to navigate a system of poorly coordinated care in the post-discharge period. Care transition interventions are seen as effective care coordinating mechanisms for reducing avoidable adverse events associated with the transition of the patient from the hospital to the home. A study was undertaken to evaluate the effectiveness of a care transition intervention involving a hand-off between a hospital-based care transitions nurse and a community-based rapid response nurse. Two focus groups were held, one involving rapid response nurses and the other involving care transition nurses. Individual interviews were conducted with the managers (n = 2) and executives (n = 2) to identify the factors that facilitated or were barriers to its implementation. Using thematic content analysis, it was found that the effectiveness of transitional coordination efforts was thwarted by ineffective communication, which affected the quality of the underlying relationships between the two teams. Other barriers to achieving the desired outcomes included the following: issues of role clarity, role awareness and acceptance, the adequacy and reinforcement of coordinating mechanisms, the effectiveness of the information exchange protocols and the absence of shared measures of accountability. Clinical integration initiatives have fewer human resource and financial implementation barriers compared with organizational integration efforts but are complex undertakings requiring clear alignment between organizations, shared accountability measures, effective communication processes and relationships of trust and respect between interprofessional teams.


Assuntos
Prática Clínica Baseada em Evidências/organização & administração , Enfermeiras e Enfermeiros/organização & administração , Alta do Paciente , Comunicação , Comorbidade , Continuidade da Assistência ao Paciente/organização & administração , Grupos Focais , Humanos , Ontário , Avaliação de Programas e Projetos de Saúde
6.
Glob Chang Biol ; 22(6): 2269-84, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26929390

RESUMO

Wheat production will be impacted by increasing concentration of atmospheric CO2 [CO2 ], which is expected to rise from about 400 µmol mol(-1) in 2015 to 550 µmol mol(-1) by 2050. Changes to plant physiology and crop responses from elevated [CO2 ] (e[CO2 ]) are well documented for some environments, but field-level responses in dryland Mediterranean environments with terminal drought and heat waves are scarce. The Australian Grains Free Air CO2 Enrichment facility was established to compare wheat (Triticum aestivum) growth and yield under ambient (~370 µmol(-1) in 2007) and e[CO2 ] (550 µmol(-1) ) in semi-arid environments. Experiments were undertaken at two dryland sites (Horsham and Walpeup) across three years with two cultivars, two sowing times and two irrigation treatments. Mean yield stimulation due to e[CO2 ] was 24% at Horsham and 53% at Walpeup, with some treatment responses greater than 70%, depending on environment. Under supplemental irrigation, e[CO2 ] stimulated yields at Horsham by 37% compared to 13% under rainfed conditions, showing that water limited growth and yield response to e[CO2 ]. Heat wave effects were ameliorated under e[CO2 ] as shown by reductions of 31% and 54% in screenings and 10% and 12% larger kernels (Horsham and Walpeup). Greatest yield stimulations occurred in the e[CO2 ] late sowing and heat stressed treatments, when supplied with more water. There were no clear differences in cultivar response due to e[CO2 ]. Multiple regression showed that yield response to e[CO2 ] depended on temperatures and water availability before and after anthesis. Thus, timing of temperature and water and the crop's ability to translocate carbohydrates to the grain postanthesis were all important in determining the e[CO2 ] response. The large responses to e[CO2 ] under dryland conditions have not been previously reported and underscore the need for field level research to provide mechanistic understanding for adapting crops to a changing climate.


Assuntos
Dióxido de Carbono/análise , Temperatura Alta , Triticum/crescimento & desenvolvimento , Água , Irrigação Agrícola/métodos , Atmosfera/análise , Biomassa , Secas , Grão Comestível/crescimento & desenvolvimento , Monitoramento Ambiental , Chuva , Vitória
7.
Springerplus ; 4: 236, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26069875

RESUMO

This study investigates the perception of historic changes in climate and associated impact on local agriculture among smallholders in pastoral/agropastoral systems of Borana in southern Ethiopia. We drew on empirical data obtained from farm household surveys conducted in 5 districts, 20 pastoral/agropastoral associations and 480 farm households. Using this data, this study analyses smallholders' perception of climate change and its associated impact on local agriculture, and the effect of various household and farm attributes on perception. Results suggest that most participants perceived climatic change and its negative impact on agricultural and considered climate change as a salient risk to their future livelihoods and economic development. Different levels of perception were expressed in terms of climate change and the impact on traditional rain-fed agriculture. Age, education level, livestock holding, access to climate information and extension services significantly affected perception levels. Household size, production system, farm and non-farm incomes did not significantly affect perception levels of smallholders. Smallholders attributed climate change to a range of biophysical, deistic and anthropogenic causes. Increased access to agricultural support services, which improves the availability and the quality of relevant climate information will further enhance awareness of climate change within of the rural community and result in better management of climate-induced risks in these vulnerable agricultural systems.

8.
Mar Pollut Bull ; 73(2): 504-15, 2013 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-23628549

RESUMO

A two-fluid, small scale numerical ocean model was developed to simulate plume dynamics and increases in water acidity due to leakages of CO2 from potential sub-seabed reservoirs erupting, or pipeline breaching into the North Sea. The location of a leak of such magnitude is unpredictable; therefore, multiple scenarios are modelled with the physiochemical impact measured in terms of the movement and dissolution of the leaked CO2. A correlation for the drag coefficient of bubbles/droplets free rising in seawater is presented and a sub-model to predict the initial bubble/droplet size forming on the seafloor is proposed. With the case studies investigated, the leaked bubbles/droplets fully dissolve before reaching the water surface, where the solution will be dispersed into the larger scale ocean waters. The tools developed can be extended to various locations to model the sudden eruption, which is vital in determining the fate of the CO2 within the local waters.


Assuntos
Dióxido de Carbono/análise , Sequestro de Carbono , Monitoramento Ambiental/métodos , Modelos Químicos , Poluentes Químicos da Água/análise , Recuperação e Remediação Ambiental , Mar do Norte , Poluição Química da Água/estatística & dados numéricos
10.
Genetica ; 138(11-12): 1191-200, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21063749

RESUMO

Pasting properties are important characteristics of barley starch from a processing standpoint. A shorter time to peak viscosity and lower pasting temperature are favorable to both malting and food processing. This study was conducted to identify quantitative trait loci (QTLs) determining pasting properties of barley flour using a doubled haploid population of 177 lines from the cross between six-rowed Yerong and two-rowed Franklin. Yerong is a feed barley with a longer time to peak viscosity and a higher pasting temperature than the other parent Franklin which is a malting barley. Field trials were conducted in three different sites/years. Seven different parameters representing the pasting properties were measured using a Rapid Visco-analyser (RVA). DH lines showed significant differences in all seven parameters in most of the sites/years. For example, the pasting temperature of different DH lines ranged from 73.8 to 89.5 in 2006/2007 MTP field trial. Twenty one QTLs were associated with flour pasting properties. These QTLs were distributed on 11 chromosome regions. Genetic variance explained by these QTLs varies from 4.4 to 15.2%. The most important QTLs controlling the time to peak viscosity and pasting temperature were located on 1H, 2H, 3H and 7H. Results showed that some of the pasting properties can be effectively selected by the combination of several molecular markers.


Assuntos
Mapeamento Cromossômico/métodos , Farinha , Hordeum/genética , Locos de Características Quantitativas , Cruzamento , Cruzamentos Genéticos , Marcadores Genéticos , Variação Genética , Haploidia , Fenótipo
11.
Plant Cell Environ ; 31(9): 1317-24, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18518914

RESUMO

A rising global population and demand for protein-rich diets are increasing pressure to maximize agricultural productivity. Rising atmospheric [CO(2)] is altering global temperature and precipitation patterns, which challenges agricultural productivity. While rising [CO(2)] provides a unique opportunity to increase the productivity of C(3) crops, average yield stimulation observed to date is well below potential gains. Thus, there is room for improving productivity. However, only a fraction of available germplasm of crops has been tested for CO(2) responsiveness. Yield is a complex phenotypic trait determined by the interactions of a genotype with the environment. Selection of promising genotypes and characterization of response mechanisms will only be effective if crop improvement and systems biology approaches are closely linked to production environments, that is, on the farm within major growing regions. Free air CO(2) enrichment (FACE) experiments can provide the platform upon which to conduct genetic screening and elucidate the inheritance and mechanisms that underlie genotypic differences in productivity under elevated [CO(2)]. We propose a new generation of large-scale, low-cost per unit area FACE experiments to identify the most CO(2)-responsive genotypes and provide starting lines for future breeding programmes. This is necessary if we are to realize the potential for yield gains in the future.


Assuntos
Dióxido de Carbono/metabolismo , Produtos Agrícolas/fisiologia , Abastecimento de Alimentos , Projetos de Pesquisa , Aclimatação , Ar , Produtos Agrícolas/genética , Genótipo , Efeito Estufa , Fenótipo , Fotossíntese/fisiologia
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