14,292 research outputs found
An analysis of the transit times of CoRoT-1b
No full textThe CoRoT satellite is expected to discover tens of new transiting exoplanets during its mission. For each of these planets there will be a resulting long, continuous sequence of transit times that can be used to search for perturbations arising from an additional planet in the system. I report the results from a study of the transit times for CoRoT-1b, which was one of the first planets discovered by CoRoT. Analysis of the pipeline-reduced CoRoT light curve yields a new determination of the physical and orbital parameters of planet and star, along with 35 individual transit times at a typical precision of 36 s. I estimate a planet-to-star radius ratio of ± 0.0010, a ratio of the planet's orbital semimajor axis to the host star radius of ± 0.045, and an orbital inclination for the planet of i=83.88\degr ± 0.29\degr. The observed transit times are consistent with CoRoT-1b having a constant period and there is no evidence of an additional planet in the system. I use the observed constancy of the transit times to set limits on the mass of a hypothetical additional planet in a nearby, stable orbit. I ascertain that the most stringent limits (4 at 3σ confidence) can be placed on planets residing in a 1:2 mean motion resonance with the transiting planet. In contrast, the data yield less stringent limits on planets near a 1:3 mean motion resonance (5 MJup at 3σ confidence) than in the surrounding parameter space. In addition, I use a simulation to investigate what sensitivity to additional planets could be obtained from the analysis of data measured for a similar system during a CoRoT long run (100 sequential transit times). I find that for such a scenario, planets with masses greater than twice that of Mars (0.2 ) in a 1:2 mean motion resonance would cause high-significance transit time deviations. Therefore, such planets could be detected or ruled out using CoRoT long run data. I conclude that CoRoT data will indeed be very useful for searching for planets with the transit timing method
Correlation of physio-chemical characteristics in the seed coat and canning quality in different dark red kidney bean (Phaseolus vulgaris l.) cultivars
No full textPlan BThe canned kidney bean (Phaseolus vulgaris L.) is one of the major consumption forms of this agricultural product. In the canning industry, seed coat splitting is considered one factor affecting the integrity of the appearance in the final product. Three different dark red kidney bean cultivars (85, 453 and Nickols) grown in the Wisconsin area were studied in this research. The physiochemical properties in this study included moisture content, the seed coat to whole seed weight ratio, the weight per seed, ash, mineral (sodium, calcium, iron, potassium and magnesium) and total crude protein content in the seed coat. The correlations of these properties with the seed coat splits were investigated. In the canned product, highly significant differences (P<0.01) in percentage of split seed coat were found among the three cultivars studied. Canned cv. 85 had significantly fewer seed coat splits than the other two cultivars. Cv. 85 was significantly higher in moisture content, as well as ash, sodium, calcium and iron content in the seed coat. The seed coat of cv. 453 was significantly higher in magnesium, and total crude protein. Cv. Nickols was found to be significantly higher in the weight per bean and seed coat splits after the canning process. Significant negative correlations were found between the percentage of seed coat splits, sodium (r = -0.89, p< 0.01), calcium (r = -0.74, P< 0.01) and iron content (r = -0.79, P< 0.05) in the seed coat. A positive correlation was found between sodium content and calcium content (r = 0.69, P< 0.05) in the seed coat. Increased calcium content in the seed coat was accompanied with increased sodium content. A significant positive relationship (r = 0.901, P< 0.01) was found between seed weight and the percentage of seed coat splits. This research suggested that several physiochemical factors of the seed coat, including weight per seed, sodium, calcium, and iron content, might play important roles in the integrity of the seed coat during the thermal processing
Complex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L)
No full textComplex toxic effects of Cd2+, Zn2+, and acid rain on growth of kidney bean (Phaseolus vulgaris L) were studied in a pot experiment by measurement of fresh weights of the plants, determination of surperoxide dismutase (SOD), peroxidase (POD), and lipid peroxidation (MDA) in the plant organs, and observation of injury symptoms. The experimental results demonstrated that all treatments of Cd2+, Zn2+, and/or acid rain significantly decreased fresh weights of kidney bean and caused toxic effects on growth of the plants, especially higher amounts of Cd2+ and Zn2+ and higher acidity of acid rain. Combination of these three pollutant factors resulted in more serious toxic effects than any single pollutant and than combinations of any two pollutants. SOD, POD, and MDA in the plant organs changed with different pollution levels, but MDA content in the leaves showed the best relationship between the pollution levels and toxic effects
L. J. Bean, ed., California Indian Shamanism
No full textDésveaux Emmanuel. L. J. Bean, ed., California Indian Shamanism. In: L'Homme, 1993, tome 33 n°126-128. La remontée de l'Amazone. p. 594
Biochemical basis of insect resistance in winged bean (Psophocarpus tetragonolbus): characterisation of insecticidal proteins and their encoding genes
No full textMany pulses and beans grown for human comsumption are susceptible to insect attack. Winged bean, a high protein crop of the tropics, yield seeds which appear to be immune to infestation by the storage bruchid Callosobruchus maculatus. In this thesis the biochemical basis of this resisitance was investigated. Insect bio-assays were carried out in which protein fractions from seeds of winged bean were incorporated at a range of concentrations into artificial seeds, and their effects upon the development of C.maculatus determined. Both albumin and globulin fractions were toxic to the developing larvae and their toxicity correlated with their haemagglutination activity. Assay of psophocarpin fractions A, B and C found the fraction psophocarpin B to be most insecticidal. On further purification this fraction yielded two lectin fractions and a protease inhibitor fraction. Purified basic lectin was highly insecticidal to C. maculatus larvae with an LC(_50) value of 0.35%. The physiological level of this protein in winged bean seeds is sufficient to account for their resistance to attack by C maculatus. Winged bean trypsin inhibitor was also purified and tested in artificial seeds against C maculatus. However, even at concentrations in excess of twice the physiological concentration it had no deleterious effects upon development. Winged bean protein fractions, incorporated in artificial diets, proved toxic to the Lepidopteran pests Heliothis virescens and Spodoptera littoralis in bio-assays, but it appeared that the basic lectin was not responsible for toxicity towards these insects. Attempts to clone the gene encoding the winged bean basic lectin were made by constructing cDNA and genomic libraries, and heterologous lectin genes from soybean and Phaseolus were investigated as possible probes for the basic lectin gene. Purification of the basic lectin B3 and sequencing of 44% of its primary protein structure, along with comparisons with other legume lectin sequences allowed the synthesis of oligonucleotide primers for use in polymerase chain reaction experiments. However, all the PGR products obtained were shown to be the result of non-specific amplification. Further work needed to obtain the basic lectin gene is discussed
The impact of STEM experiences on student self-efficacy in computational thinking
No full textCitation: Weese, J. L., Feldhausen, R., & Bean, N. H. (2016). The impact of STEM experiences on student self-efficacy in computational thinking.Since the introduction of new curriculum standards at K-12 schools, computational thinking has become a major research area. Creating and delivering content to enhance these skills, as well as evaluation, remain open problems. This paper describes two different interventions based on the Scratch programming language which aim to improve student self-efficacy in computer science and computational thinking. The two interventions were applied at a STEM outreach program for 5th-9th grade students. Previous experience in STEM related activities and subjects, as well as student self-efficacy, were collected using a developed pre- and post-survey. We discuss the impact of our intervention on student performance and confidence, and evaluate the validity of our instrument. © American Society for Engineering Education, 2016
Breeding phaseolus vulgaris (common bean) for resistance to the major pest bruchids Zabrotes subfasciatus and Acanthoscelides obtectus. Biochemical bases for seed resistance in wild lines
No full textPhaseolus vulgaris (common bean) is an important source of protein for human and animal consumption. Economic losses post-harvest in storage are primarily due to the bruchid beetles Acanthoscelides obtectus (Bean Weevil) and Zabrotes subfasciatus (Mexican Bean Weevil). Wild-lines exhibiting resistance to these two species have been found and the mechanisms of resistance to each species are investigated. The mechanisms of resistance to the two species are found to be multiple, and different for each species. In the case of Z. subfasciatus, the presence of a novel storage protein and absence of the conventional storage protein constitutes the primary mechanism. The novel protein ("arcelin") is antimetabolic when included in artificial diets. In vitro digestibility studies indicate that it is indigestible to Z. subfasciatus larval gut proteases, and since arcelin constitutes the major protein of the seed the larvae starve. Arcelin has a similar amino- acid sequence to PHA. Also present is WBAI, a highly specific inhibitor of larval amylase of the two bruchid pests Z. subfasciatus and Callosobruchus maculatus, whilst having virtually no inhibitory activity on the mammalian amylase, nor on other insect, bacterial nor fungal enzymes. WBAI is similar in gross structure to the conventional amylase inhibitor obtainable from RKB (commercial P. vulgaris), and both are also immunologically similar to PHA. Both of these mechanisms are suitable for incorporation into commercial seed, and the former has already been tested, using meal from seeds, in feeding trials using rats, confirming absence of mammalian toxicity. Resistance to A. obtectus damage is accompanied by reduced starch content, and high content of an acidic polysaccharide (whose structure has not been elucidated). No protein cause for resistance was found. Inheritance of resistance to A. obtectus is recessive. Since the factor responsible for resistance is not a primary gene product and is expressed recessively, this factor is unsuitable for incorporation into breeding lines to be used for developing commercial cultivars
Construction of a comparative genetic map in faba bean (Vicia faba L.); conservation of genome structure with Lens culinaris
No full textBackground
The development of genetic markers is complex and costly in species with little pre-existing genomic information. Faba bean possesses one of the largest and least studied genomes among cultivated crop plants and no gene-based genetic maps exist. Gene-based orthologous markers allow chromosomal regions and levels of synteny to be characterised between species, reveal phylogenetic relationships and chromosomal evolution, and enable targeted identification of markers for crop breeding. In this study orthologous codominant cross-species markers have been deployed to produce the first exclusively gene-based genetic linkage map of faba bean (Vicia faba), using an F6 population developed from a cross between the lines Vf6 (equina type) and Vf27 (paucijuga type).
Results
Of 796 intron-targeted amplified polymorphic (ITAP) markers screened, 151 markers could be used to construct a comparative genetic map. Linkage analysis revealed seven major and five small linkage groups (LGs), one pair and 12 unlinked markers. Each LG was comprised of three to 30 markers and varied in length from 23.6 cM to 324.8 cM. The map spanned a total length of 1685.8 cM. A simple and direct macrosyntenic relationship between faba bean and Medicago truncatula was evident, while faba bean and lentil shared a common rearrangement relative to M. truncatula. One hundred and four of the 127 mapped markers in the 12 LGs, which were previously assigned to M. truncatula genetic and physical maps, were found in regions syntenic between the faba bean and M. truncatula genomes. However chromosomal rearrangements were observed that could explain the difference in chromosome numbers between these three legume species. These rearrangements suggested high conservation of M. truncatula chromosomes 1, 5 and 8; moderate conservation of chromosomes 2, 3, 4 and 7 and no conservation with M. truncatula chromosome 6. Multiple PCR amplicons and comparative mapping were suggestive of small-scale duplication events in faba bean. This study also provides a preliminary indication for finer scale macrosynteny between M. truncatula, lentil and faba bean. Markers originally designed from genes on the same M. truncatula BACs were found to be grouped together in corresponding syntenic areas in lentil and faba bean.
Conclusion
Despite the large size of the faba bean genome, comparative mapping did not reveal evidence for polyploidisation, segmental duplication, or significant rearrangements compared to M. truncatula, although a bias in the use of single locus markers may have limited the detection of duplications. Non-coding repetitive DNA or transposable element content provides a possible explanation for the difference in genome sizes. Similar patterns of rearrangements in faba bean and lentil compared to M. truncatula support phylogenetic studies dividing these species into the tribes Viceae and Trifoliae. However, substantial macrosynteny was apparent between faba bean and M. truncatula, with the exception of chromosome 6 where no orthologous markers were found, confirming previous investigations suggesting chromosome 6 is atypical. The composite map, anchored with orthologous markers mapped in M. truncatula, provides a central reference map for future use of genomic and genetic information in faba bean genetic analysis and breeding
A Nonparametric Efficiency Analysis of Bean Producers from North and South Kivu
No full textThe purpose of this research is to determine how technically efficient small-scale producers are in two provinces (North and South Kivu) in the Democratic of Republic (DR) of Congo at producing two different varieties of beans: bush and climbing beans. In addition to calculating the efficiency scores, this research attempts to identify what producer and field characteristics affect these scores. We hypothesize that bean producers will be more productive than producers in South Kivu and that climbing bean producers will be more productive than bush bean producers. Technical efficiency is estimated using a nonparametric approach. A tobit model is used to examine the effect of producer and field characteristic on the efficiency score. On average, farms were 66% technically efficient. North Kivu bean producers and climbing bean producers have, on average, a higher technical efficiency score than their counterparts. Implications from this research suggest that there is room for improvement in the technical efficiency scores for producers in DR of Congo. Based on the results, it may be more productive to continue focusing on improving the yield and nutritional content of climbing beans.Production Economics, Production Economics,
Impact of pre‐treatment (soaking or germination) on nutrient and anti‐nutrient contents, cooking time and acceptability of cooked red dry bean ( Phaseolus vulgaris L.) and chickpea ( Cicer arietinum L.) grown in Ethiopia
No full textPulses are processed in diverse ways prior to consumption. Soaking and germination are among the most common traditional, household‐level food processing strategies. This study was carried out to determine the effects of soaking, germination, cooking and their combinations on the contents of selected nutrients and anti‐nutrients of red dry bean and chickpea. In addition, the effects of pre‐treatment on cooking time and the acceptability of dishes prepared from red dry bean and chickpea were determined. The nutrient compositions (zinc, iron and calcium) of most soaked‐cooked and germinated‐cooked red dry bean and chickpea samples were not significantly different than those of respective controls. However, soaking and germination pre‐treatments significantly lowered the phytate and tannin contents of the red dry bean and chickpea samples, with a few exceptions, and overall, polyphenol contents were lower after soaking‐cooking than after germination‐cooking. Most scores for sensory attributes of bean‐based and chickpea‐based dishes prepared from soaked or germinated samples were not significantly different than those of the controls. For most red dry bean and chickpea samples, longer germination times yielded superior results in terms of reductions in cooking time, tannin content, and phytate:zinc and phytate:iron molar ratio
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