Male remating in Drosophila ananassae: evidence for interstrain variation for remating time and shorter duration of copulation in second mating

ABSTRACT—In Drosophila ananassae, male remating was studied using ten mass culture stocks which were initiated from flies collected from different geographic localities. Male remating occurs at a high fre-quency and varies within narrow limits (84–96 percent) in different strains. Interestingly, male remating time (in min) varies from 7.41 (Bhutan) to 21.59 (PAT) in different strains and the variation is highly significant. Further, the results also show that males copulate for shorter duration during second mating. This is the first report in the genus Drosophila which provides evidence for interstrain variations for male remating time as well as for shorter duration of copulation during second mating as compared to first mating in D. ananassae

Female remating in Drosophila ananassae: effect of density on female remating frequency

Drosophila ananassae, a cosmopolitan and domestic species, is largely cir-cumtropicalin distribution and belongs to the ananassae species complex of the ananassae subgroup of the melanogaster species group. In the present study, experiments were conducted to investigate the effect of density on fe-male remating frequency by employing different wild-type and mutant strains of D. ananassae. Two experimental designs, i.e., 2-h daily observation and continuous confinement, were used. The results show that there is significant dependence of remating frequency on density in all strains tested under both experimental designs except in a wild-type strain (Bhutan), which shows no dependence of remating frequency on density under 2-h daily observation de-sign. This finding provides evidence that density may increase the frequency of female remating in D. ananassae

Female remating in Drosophila ananassae: bidirectional selection for remating speed

In Drosophila ananassae, artificial selection was carried out for fast and slow remating speed for 10 generations. Response to selection resulted in rapid divergence in remating time in each of two replicates of both fast and slow lines. There were significant differences in mean remat-ing time in females among fast, slow, and control lines. Regression coefficients for both fast and slow lines are significantly different from zero. The realized heritability over 10 genera-tions of selection is from 0.26 to 0.33 for two replicates of fast line and from 0.23 to 0.27 for two replicates of slow line. These findings suggest that female remating time in D. ananassae is under polygenic control. Remating frequency of females showed a correlated response in both fast and slow lines. At generation 10, correlated response to selection was also investigated. Mating propensity of D. ananassae of fast and slow lines was observed in an Elens-Wattiaux mating chamber. Fifteen pairs per test showed that on the average, the fast lines (11.20, 11.60) were more successful in mating than those of slow (6.40, 5.60) and control (8.00) lines. Pro-ductivity of once-mated females was measured in terms of number of progeny produced per fe-male and the results of productivity analysis indicate that females of fast lines (157.83, 130.83) produced more progeny compared with slow (72.70, 85.83) and control (109.23) lines

Conceptos basicos para el mejoramiento del frijol por hibridacion

The basic concepts of the genetic improvement of beans through hybridization are described. In general, the breeding process involves the following phases: (1) development of exptl. lines, (2) evaluation of exptl. lines and identification of new cv., and (3) commercialization of new cv. The main aspects that should be considered in the development of exptl. lines as well as the most common breeding methods used in beans (modified pedigree, mass- pedigree, and backcrossing) are described. The evaluation of exptl. lines and the identification of new cv. are carried out in 3 or more steps: adaptation nurseries, preliminary yield trials, and regional yield trials. For the commercialization of new cv. the newly identified materials are registered, multiplied, and distributed. (CIAT)Se describen los conceptos basicos de mejoramiento genetico del frijol por hibridacion. En general, el proceso de mejoramiento involucra las siguientes fases: 1) el desarrollo de lineas exptl., 2) la evaluacion de las lineas exptl. y la identificacion de los nuevos cv. y 3) la comercializacion de nuevos cv. Se describen los aspectos importantes que deben considerarse en el desarrollo de las lineas exptl. y los metodos de mejoramiento mas comunes utilizados en el frijol (pedigri modificado, masal-pedigri y retrocruzamiento). La evaluacion de las lineas exptl. y la identificacion de nuevos cv. se realizan en 3 o mas etapas: viveros de adaptacion, ensayos preliminares de rendimiento y pruebas regionales de rendimiento. Para la comercializacion de nuevos cv., los materiales recien identificados se registran, se multiplican y se distribuyen. (CIAT

Understanding the Impact of Early Citers on Long-Term Scientific Impact

This paper explores an interesting new dimension to the challenging problem of predicting long-term scientific impact (LTSI) usually measured by the number of citations accumulated by a paper in the long-term. It is well known that early citations (within 1-2 years after publication) acquired by a paper positively affects its LTSI. However, there is no work that investigates if the set of authors who bring in these early citations to a paper also affect its LTSI. In this paper, we demonstrate for the first time, the impact of these authors whom we call early citers (EC) on the LTSI of a paper. Note that this study of the complex dynamics of EC introduces a brand new paradigm in citation behavior analysis. Using a massive computer science bibliographic dataset we identify two distinct categories of EC - we call those authors who have high overall publication/citation count in the dataset as influential and the rest of the authors as non-influential. We investigate three characteristic properties of EC and present an extensive analysis of how each category correlates with LTSI in terms of these properties. In contrast to popular perception, we find that influential EC negatively affects LTSI possibly owing to attention stealing. To motivate this, we present several representative examples from the dataset. A closer inspection of the collaboration network reveals that this stealing effect is more profound if an EC is nearer to the authors of the paper being investigated. As an intuitive use case, we show that incorporating EC properties in the state-of-the-art supervised citation prediction models leads to high performance margins. At the closing, we present an online portal to visualize EC statistics along with the prediction results for a given query paper

Comparison of mass, F\u3csub\u3e2\u3c/sub\u3e-derived family, and single-seed-descent selection methods in an interracial population of common bean

Knowledge of comparative effectiveness of different selection method is necessary for identification of superior genotypes, efficient management of populations, and use of available resources. Mass, F2-derived-family, and single-seed-descent (SSD) selection methods were compared in an interracial population (ICA pijao x Pinto UI 114) of common bean (Phaseolus vulgaris L.). The F2-derived-family -method involved elimination of low-yielding F2-derived families in replicated yield trials in F4, F5 and F6. Thirty-two random lines derived from each method and the two parents were evaluated in a replicates-in-set design in two contrasting environments in Colombia in 1992. Mean seed yield of lines derived from the SSD method was significantly lower than yields obtained from the other two methods. Mean yield of lines derived from the pedigree method was the highest, indicating that even a low intensity of selection for yield among F2-derived families was effective. The F2-derived-family method also retained a comparatively higher proportion of lines with lighter-colored medium-sized seeds and indeterminate prostrate type III growth habit. Lines with darker and smaller seeds predominated in the mass and SSD methods. These two groups also had more erect type II lines than did the F2-derived family method. On average, the SSD gave early maturing and the mass method late maturing lines. No line from any method outyielded ICA Pijao, the high-yielding parent. Two lines from the F2-derived-family method, four Iines from the mass method, and no lines from the SSD method significantly outyielded Pinto UI 114

Uso de marcadores y selección de gametos para el mejoramiento simultáneo de caracteres múltiples de frijol (Phaseolus vulgaris L.) para Mesoamérica y el Caribe.

El objetivo fue describir requerimientos básicos y métodos alternativos de selección para el mejoramiento simultáneo en frijol común, en el tiempo más corto posible y considerando el máximo número de caracteres agronómicos. Esta estrategia incluye: (1) obtener claridad sobre la importancia y problemática del cultivo de frijol para la zona, (2) fijar objetivos y prioridades del mejoramiento genético, (3) identificar y usar únicamente padres que con absoluta confianza pueden considerarse donantes de genes necesarios, (4) utilizar cruzamientos múltiples con un número adecuado de polinizaciones para producir suficiente semilla de cada cruza, (5) realizar evaluación y selección para marcadores actualmente disponibles (e.g., para gorgojo, mosaico común, mosaico dorado, antracnosis, picudo, bacteriosis común y roya, entre otros) desde la etapa de hibridación, (6) métodos alternativos de selección; como selección de gametos y descendiente de semilla única (SG-DSU), selección de gametos y pedigrí usando marcadores (SG-PUM), selección de gametos y evaluación y selección agronómica de familias en generaciones tempranas (SG-EAF), o una combinación e integración de los métodos SG-PUM y SG-EAF; y (7) conseguir una estrecha y genuina colaboración e integración de actividades de mejoramiento entre diferentes investigadores a nivel de instituciones, países y la región entera, en localidades claves, para efectuar evaluaciones confiables de viveros de frijol a efectos de realizar selección simultánea para el máximo número de caracteres agronómicos

When questions become answers

Questions question our understanding of concepts, situations and ideas. There is no question about this. This is an account of the way one teacher,Kinzom Khampa, used the tool of inquiry to get children find the answers

Müllerian duct cyst misdiagnosed as ovarian cyst: a rare case report

The Müllerian duct cyst is a remnant of the caudal ends of the fused embryologic paramesonephric ducts (or Müllerian ducts). Preoperative distinction of ovarian cyst from a Müllerian duct cyst is important and is based on visualization of the ipsilateral ovary separate from the mass. Müllerian duct cysts may also be mistaken as paratubal, paraovarian or peritoneal inclusion cysts and hydrosalpinx. Thus, preoperative diagnosis of Müllerian cyst of the uterus can be very challenging. However, with increased awareness, preoperative diagnosis of this condition should be possible by sonography. Laparoscopy is useful as a minimally invasive treatment to diagnose as well as resect the cyst at the same time. We present a rare case of Müllerian duct cyst misdiagnosed as ovarian cyst pre-operatively and managed laparoscopically. A 32 year old multiparous female presented with the complaint of lump and dull aching pain in lower abdomen since three months. A cystic mobile mass measuring 6X7 cm with smooth surface which corresponded to 16 weeks gravid uterus size was palpated arising from pelvis. Her pelvic ultrasonography revealed a 7X7 cm unilocular thin walled simple cyst in right ovary suggestive of serous cystadenoma. Her CA-125 was 5.3 IU/ml. She was taken up for laparoscopic ovarian cystectomy. Intra-operatively, a 7X7 cm cyst was seen arising from right lateral wall of uterus. Histopathology showed the cyst wall features consistent with a Müllerian duct cyst