Journal articles: 'Esox – Reproduction'

1

Kristan, Jiri, Azin Mohagheghi Samarin, Oleksander Malinovskyi, and Tomáš Policar. "Gamete management for artificial reproduction of northern pike Esox lucius (Linnaeus, 1758)." Aquaculture 528 (November 2020): 735575. http://dx.doi.org/10.1016/j.aquaculture.2020.735575.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Bry, C., J. F. Batisse, and G. Neveu. "Survival of pike (Esox lucius L.) broodstock in relation to type of reproduction." Aquaculture 83, no. 3-4 (December 1989): 387–95. http://dx.doi.org/10.1016/0044-8486(89)90049-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

3

Weber, Michael J., and Michael L. Brown. "Application of a robust design occupancy model for assessing fish recruitment." Canadian Journal of Fisheries and Aquatic Sciences 76, no. 4 (April 2019): 561–68. http://dx.doi.org/10.1139/cjfas-2018-0083.

Full text

Abstract:

Fish recruitment is complex, regulated by environmental factors that induce high mortality early in life. Additionally, age-0 fish can be difficult to sample, making recruitment difficult to detect. We used a robust design occupancy model to evaluate the effects of biotic (age-0 and adult common carp (Cyprinus carpio), bluegill (Lepomis macrochirus), walleye (Sander vitreus), and northern pike (Esox lucius) relative abundance, prey availability, age-0 carp length) and abiotic (water level, temperature) factors on age-0 carp occupancy, detection, and extinction in 13 lakes in South Dakota, USA, for July–April 2008–2010. Age-0 carp occupancy decreased with increasing adult carp abundance and increased with increasing water levels. Age-0 carp detection probability was high during summer (>0.75) but decreased in fall and spring (0.34). Most lakes were occupied in July but overwinter extinction probability was high (59%), resulting in 51% occupancy probability by April. Other environmental factors were not supported, suggesting they had little effect on reproduction and survival. Our results indicate reproduction was universally successful but difficult to detect and that overwinter mortality often resulted in recruitment failure.

APA, Harvard, Vancouver, ISO, and other styles

4

Hontela, Alice, Joseph B. Rasmussen, and Gaston Chevalier. "Endocrine Responses as Indicators of Sublethal Toxic Stress in Fish from Polluted Environments." Water Quality Research Journal 28, no. 4 (November 1, 1993): 767–80. http://dx.doi.org/10.2166/wqrj.1993.042.

Full text

Abstract:

Abstract Development of new methods for detection of sublethal toxic effects of pollutants in aquatic organisms has become a focus of interest in ecotoxicology. The endocrine response to pollutants is an integral part of the homeostatic physiological processes activated in response to environmental stressors including pollutants. Changes in concentrations of hormones, particularly those regulating vital functions such as osmoregulation, energy metabolism, reproduction, or growth, may have potential as early warning indicators of toxic stress in fish. We review the recent literature in fish endocrine toxicology and illustrate the use of hormonal indicators in detection of acid stress in the brook trout. Salvelinus fontinalis, from lakes in the Canadian Shield, and of general toxic stress in the pike, Esox lucius, and the perch, Perca flavescens, from the St. Lawrence River system polluted by a mixture of chemicals.

APA, Harvard, Vancouver, ISO, and other styles

5

Möller, Sören, Helmut M. Winkler, Andreas Klügel, and Stefan Richter. "Using otolith microchemical analysis to investigate the importance of brackish bays for pike ( Esox lucius Linnaeus, 1758) reproduction in the southern Baltic Sea." Ecology of Freshwater Fish 28, no. 4 (March 20, 2019): 602–10. http://dx.doi.org/10.1111/eff.12478.

Full text

APA, Harvard, Vancouver, ISO, and other styles

6

Plourde-Lavoie, Patrick, Marc Archer, Karine Gagnon, and Pascal Sirois. "Les variations de niveau du lac Saint-Jean : effets sur la reproduction des poissons dans les habitats en milieux humides riverains." Le Naturaliste canadien 142, no. 1 (November 22, 2017): 66–77. http://dx.doi.org/10.7202/1042015ar.

Full text

Abstract:

Le lac Saint-Jean a vu son régime hydrologique considérablement modifié depuis sa transformation en réservoir en 1926. Cet article examine les effets de la gestion du niveau du lac pour la fraie de la perchaude (Perca flavescens) et du grand brochet (Esox lucius). Une analyse des niveaux des eaux des 100 dernières années a permis de mettre en évidence une réduction des écarts entre les niveaux printaniers et estivaux, qui contribue vraisemblablement à diminuer la taille et la qualité des sites de reproduction, et un retardement de l’atteinte du niveau maximal au printemps par rapport au régime naturel. L’utilisation de données historiques de températures du lac et des milieux humides riverains a permis d’estimer les périodes de fraie de 1991 à 2015 et de mettre en évidence les conséquences des bas niveaux au printemps sur l’accessibilité des milieux humides. À présent, ces habitats ne sont généralement que partiellement inondés lors de la fraie des 2 espèces. Nous recommandons d’adopter une gestion du lac Saint-Jean qui vise à devancer l’atteinte des hauts niveaux printaniers et à maximiser les écarts entre les niveaux printaniers et estivaux, tout en maintenant un niveau stable au printemps pour permettre l’éclosion des oeufs de poissons et assurer la survie des jeunes stades de vie.

APA, Harvard, Vancouver, ISO, and other styles

7

Edeline, Eric, Thrond O. Haugen, Finn-Arne Weltzien, David Claessen, Ian J. Winfield, Nils Chr Stenseth, and L. Asbjørn Vøllestad. "Body downsizing caused by non-consumptive social stress severely depresses population growth rate." Proceedings of the Royal Society B: Biological Sciences 277, no. 1683 (November 18, 2009): 843–51. http://dx.doi.org/10.1098/rspb.2009.1724.

Full text

Abstract:

Chronic social stress diverts energy away from growth, reproduction and immunity, and is thus a potential driver of population dynamics. However, the effects of social stress on demographic density dependence remain largely overlooked in ecological theory. Here we combine behavioural experiments, physiology and population modelling to show in a top predator (pike Esox lucius ) that social stress alone may be a primary driver of demographic density dependence. Doubling pike density in experimental ponds under controlled prey availability did not significantly change prey intake by pike (i.e. did not significantly change interference or exploitative competition), but induced a neuroendocrine stress response reflecting a size-dependent dominance hierarchy, depressed pike energetic status and lowered pike body growth rate by 23 per cent. Assuming fixed size-dependent survival and fecundity functions parameterized for the Windermere (UK) pike population, stress-induced smaller body size shifts age-specific survival rates and lowers age-specific fecundity, which in Leslie matrices projects into reduced population rate of increase ( λ ) by 37–56%. Our models also predict that social stress flattens elasticity profiles of λ to age-specific survival and fecundity, thus making population persistence more dependent on old individuals. Our results suggest that accounting for non-consumptive social stress from competitors and predators is necessary to accurately understand, predict and manage food-web dynamics.

APA, Harvard, Vancouver, ISO, and other styles

8

Jurajda, Pavel, Michal Janáč, Kevin Roche, Libor Mikl, Luděk Šlapanský, Ivo Krechler, Zdeněk Adámek, Zdenka Jurajdová, and Karel Halačka. "Fish Communities of Five Drinking Water Reservoirs in the Morava River Basin." Acta Universitatis Agriculturae et Silviculturae Mendelianae Brunensis 66, no. 3 (2018): 655–63. http://dx.doi.org/10.11118/actaun201866030655.

Full text

Abstract:

While fish communities have been studied in Czech reservoirs for decades, monitoring has increased since implementation of the EU Water Framework Directive (2000/60/EC). Despite this, many smaller drinking water reservoirs have yet to be surveyed. Between May and July 2016, we undertook a pilot‑study examining the fish communities of five Moravian reservoirs (Ludkovice, Bojkovice, Hubenov, Nová Říše and Landštejn). Fish were sampled using boat electrofishing along the littoral zone and Nordic gill nets in the pelagic zone. Both methods were evaluated separately and combined as CPUE and relative abundance and biomass ( %). Nineteen fish species and one hybrid were recorded, with roach Rutilus rutilus dominating overall by abundance, but carp Cyprinus carpio, pike Esox lucius and wels Silurus glanis dominating by biomass in electrofishing samples. Predatory species represented up to 60 % of biomass in the combined sample, with an F/C index ranging from 0.5–3, implying a high abundance of predators. Electrofishing tended to underestimate the abundance of bleak and ruffe, while gill nets underestimated the biomass of predatory species. In some reservoirs, the abundance of pike and wels was high (though it is difficult to say if these fish were stocked or the result of natural reproduction). In others (e.g. Landštejn), zander Sander lucioperca were not registered by either sampling method, despite intensive stocking. Overall, gill netting alone appears inadequate for gaining a true picture of the fish community in reservoirs and we suggest a combination of electrofishing and gill netting in future.

APA, Harvard, Vancouver, ISO, and other styles

9

Lebeau, Bernard. "Oocyte recruitment and spawning chronology in pike, Esox lucius, and muskellunge, Esox masquinongy." Canadian Journal of Zoology 69, no. 8 (August 1, 1991): 2194–201. http://dx.doi.org/10.1139/z91-306.

Full text

Abstract:

During the reproductive cycle, the progression of oogenesis differs markedly between northern pike, Esox lucius Linnaeus, and muskellunge, Esox masquinongy Mitchill. Both species have group-synchronous ovaries but have different oocyte recruitment strategies. Pike is a single spawner, developing eggs in a single clutch annually, whereas muskellunge is a fractional spawner, producing two clutches of eggs per year. During the spawning period in large female muskellunge, oocyte counts indicate that the second clutch of eggs is equally important to the first. An event portrait of the spawning period for muskellunge is provided, whereby arrival of adults to a spawning site, egg yield, and hatching success agree with the fractional spawner concept. A hypothesis of the temporal sequence of evolutionary relationships in recruitment of oocytes for esocoid fishes is presented. The reproductive strategy of muskellunge belongs to a common esocoid ancestor, whereas that in pike is derived and unique. The significance of this divergence in closely related species remains consistent with the ecological theory that evolution of reproductive strategies is adaptive to diverse environmental conditions.

APA, Harvard, Vancouver, ISO, and other styles

10

Crossman, E. J. "Reproductive Homing in Muskellunge, Esox masquinongy." Canadian Journal of Fisheries and Aquatic Sciences 47, no. 9 (September 1, 1990): 1803–12. http://dx.doi.org/10.1139/f90-205.

Full text

Abstract:

The number and nature of muskellunge moving to and from spawning grounds are extensively documented. Individual spawning muskeliunge in Stony Lake, Ontario are considered to home annually to specific spawning grounds and to specific areas (spawning sites) within spawning grounds. Some individuals were caught in the same location, or a nearby location, in as many as 7 yr. There is some evidence for discrete populations with apparent reproductive isolation and no interchange in summer. Dispersal from spawning grounds to summer home ranges seems to be limited in regard to direction and area of the lake. Recapture of fish on spawning grounds suggests an obligatory return to a limited number of "traditional" spawning grounds and may extend our knowledge of the groups of fishes exhibiting this type of directed movement. The results also have serious implications for muskellunge in regard to management, shoreline development, and genetic contamination by fish culture activities.

APA, Harvard, Vancouver, ISO, and other styles

11

Calvo, Jorge, Elba Morriconi, and Gustavo A. Rae. "Reproductive biology of the icefish Champsocephalus esox (Günther, 1861) (Channichthyidae)." Antarctic Science 11, no. 2 (June 1999): 140–49. http://dx.doi.org/10.1017/s0954102099000206.

Full text

Abstract:

Champsocephalus esox is the only icefish species found outside Antarctica. In a population from the Beagle Channel, the complete annual reproductive cycle has been determined. Gonad maturity stages have been established for males and females by histological analysis. Males are sexually mature from January–September with a maximum gonadosomatic index (GSI) of 3.63%. Histologically, testes are very homogeneous and the degree of maturation of the testicular cysts is similar among different tubules at the same maturation stage. Running ripe testes have mature sperm and a few spermatogoniae arranged near the blind end of the tubules. In sexually active females that are found from February–November, ovaries contain only ripe oocytes or postovulatory follicles, together with a batch of previtellogenic oocytes. During hydration, oocyte diameter reaches 2.7 mm, and oocyte dry weight increases due to material intake, the maximum GSI in ovulated ovaries is 21.89 and hepatosomatic index (HSI) decreases. These facts suggest a transfer of matter from liver to the gonads. Absolute fecundity ranges from 3303–8600 oocytes. Relative fecundity ranges from 22.5–43.5 oocytes per gram total weight. In C. esox, relative fecundity has a similar range to those quoted for the different C. gunnari populations, whilst mature oocyte diameter is small and reproductive season extended compared to the same parameters in other Channichthyidae.

APA, Harvard, Vancouver, ISO, and other styles

12

Demény, Ferenc. "Clay-pit systems fishfaunistic research in the Middle-Tisza." Acta Agraria Debreceniensis, no. 25 (April 11, 2007): 81–92. http://dx.doi.org/10.34101/actaagrar/25/3040.

Full text

Abstract:

After the regulation of the Tisza River the chance of successful fish propagation lessened. Natural spooning places in the river almost completely disappeared. The fish have to find an adequate place for their propagation in the flood plain. The period of spooning usually coincides with flooding of the river. At this time fish try to find the flooded shallow places for spooning. These parts mostly include the clay-pits beside dams, which were accidentally established during construction of the dams. At this place the fry can find the necessary food. After decreasing the flood the fingerlings and a part of the spooners are trapped inclay-pits as these latter ones are not connected with the river bed. The clay-pits usually desiccate during the summer. The trapped fish population is eaten by water birds or harvested by the local man population. This means a great loss for reproduction of some fishspecies.Within the framework of the Regional Rehabilitation Program at Nagykörű, supported by the “WWF Hungary” and a “SAPARD project,” these clay-pits became connected with each other in a stretch of 5 km, and they were jointed to the Tisza by a collecting channel. The water level has been regulated by a flood gate so that the water enters the holes during the flood and is released later on in to the water bed.Data on fish were collected from the Nagykörű Whole System, from the Anyita pond and some isolated wholes in Szandaszöllős in 2004 and 2005. First of all fish fry and fingerling were collected and the success of spooning at these places was examined. Fry was harvested by a 60 x 80 cm sized lifting net of 2x3 mm mesh size. In other cases nets used by anglers for catching prey fishes was also used. Data were also collected from local fishermen who participated in saving the fry and fishing of Anyita pond.Of the several thousand caught fish specimens 28 species were identified, and among them 5 protected and 5 economically important species was found. Protected fishes were as follow: gudgeon (Gobio gobio), bitterling (Rhodeus sericeus amarus), weather fish (Misgurnus fossilis), spined loach (Cobitis elongatoides) and tubenosed goby (Proterorhinus marmoratus). Among economically important fishessamples of asp (Aspius aspius), carp (Cyprinus carpio), wels (Silurus glanis), pike (Esox lucius) and pikeperch (Sander lucioperca) were

APA, Harvard, Vancouver, ISO, and other styles

13

Parfenyuk, I. O., Yu R. Grokhovskaya, and Yu M. Mandygra. "Analysis of water quality of a reservoir on a small river and the status of ichthyofauna in anthropogenic conditions." Ukrainian Journal of Veterinary and Agricultural Sciences 2, no. 3 (December 26, 2019): 28–31. http://dx.doi.org/10.32718/ujvas2-3.07.

Full text

Abstract:

The surface waters of the estuaries of the estuary are mostly characterized by low quality, which was formed as a result of considerable anthropogenic loading and transformation of the catchment area. The monitoring data of the ecological and sanitary status of the surface waters of the Basov Kut reservoir are presented, as well as the results of accounting for dead fish due to the frosts that occurred in the mouth of the Ustye River during 2011–2017. It is established that the Bas Basin is not suitable for recreational use. Amateur fisheries are also a danger to the population, as lactose-positive E. coli, the Staphylococcus aureus index, the Enterococcus microorganism index, Lamblia intestinalis cysts and eggs are detected in this reservoir annually. In 2017, cholera vibrios (Vibrio cholera non O1) were detected. Hydrochemical indicators, in particular in 2018, revealed inconsistency with the following indicators: odor – 2 points; color 3; BOD5 – 6.5–7.5 mgO2/dm³; COD 40–50 mgO2/dm³. In samples tested for sanitary – microbiological and parasitological parameters, cholera – like vibrio (non O1) was detected. The deterioration of water quality by the content of biogenic elements, in particular, compounds of Nitrogen and Phosphorus, which leads to increased eutrophication of the reservoir. The “flowering” of water in 2018 began in the third decade of June and lasted until October. This process harms not only hydrobionts, but also humans, as blue-green algae toxins can accumulate in fish tissues and cause poisoning when consumed by such products. In addition, there was a significant percentage of fish that did not meet the requirements of DSTU 2284: 2010 in terms of organoleptic characteristics. The greatest damage to the populations of fish that inhabit the Estuary during the fatalities was caused in 2012. When the estimated loss of fishery resources amounted to 377.4 thousand individuals, according to scientists and control bodies. Annual fatalities have led to quite significant losses of populations of industrially valuable fauna. A significant loss of fishery resources was noted in 2017 – about 10.32 thousand. It was noted that the following populations of fish were most affected by the frost in the estuary: Rutilus rutilus, Scardinius erythrophthalmus, Leucaspius delineatus, Perca fluviatilis, Carassius gibelio, Tinca tinca, Esox lucius, Sander luciocaper, Abracerperis This poses a significant threat to the further reproduction of ichthyofauna in the mouth of the Ustya River, and also calls into question the possibility of amateur fishing in these sites.

APA, Harvard, Vancouver, ISO, and other styles

14

Lenhardt, M., and P. Cakic. "Seasonal reproductive cycle of pike, Esox lucius L., from the River Danube." Journal of Applied Ichthyology 18, no. 1 (February 2002): 7–13. http://dx.doi.org/10.1046/j.1439-0426.2002.00285.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

15

Lebeau, Bernard, and Gérard Pageau. "Comparative urogenital morphology and external sex determination in muskellunge, Esox masquinongy Mitchill." Canadian Journal of Zoology 67, no. 4 (April 1, 1989): 1053–60. http://dx.doi.org/10.1139/z89-146.

Full text

Abstract:

Primary and secondary sexual characteristics in northern pike, Esox lucius Linneaus, and muskellunge, Esox masquinongy Mitchill, differ markedly. Differences in the internal urogenital anatomy include the structure of the genital ducts and the angle they form with the ventral surface. Externally, the genital and urinary ducts open directly to the environment in northern pike, whereas in muskellunge they open into a muscular papilla and then through a urogenital pore. Differences in sexual dimorphism between the two closely related esocids constitute a structural basis to explain the known differences in spawning behaviour and reproductive success. Differences in secondary sexual characteristics explain why the methods developed by Demchenko or Casselman to externally sex pike are inapplicable to muskellunge. To develop and test two external sexing techniques for muskellunge, specimens were collected from two regions in Canada from 1980 to 1987. Examination of reproductive products obtained from stripping provided an accurate indicator of sex and sexual maturity, but demonstrated serious limitations. A simple method to sex muskellunge by examination of the external urogenital morphology is described for juveniles and adults. Dissection of fish revealed that with the urogenital examination technique we sexed juveniles with a success rate of 92–98%, and adults with 100% accuracy.

APA, Harvard, Vancouver, ISO, and other styles

16

Treasurer, J. W. "The annual reproductive cycle of pike, Esox lucius L., in two Scottish lakes." Journal of Fish Biology 36, no. 1 (January 1990): 29–46. http://dx.doi.org/10.1111/j.1095-8649.1990.tb03517.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

17

Westin, L. "Newly discovered reproductive isolation reveals sympatric populations of Esox lucius in the Baltic." Journal of Fish Biology 61, no. 6 (December 2002): 1647–52. http://dx.doi.org/10.1006/jfbi.2002.2172.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Westin, L., and K. E. Limburg. "Newly discovered reproductive isolation reveals sympatric populations of Esox Indus in the Baltic." Journal of Fish Biology 61, no. 6 (December 2002): 1647–52. http://dx.doi.org/10.1111/j.1095-8649.2002.tb02505.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

19

Kato, Keizo, Aline M. Morrison, Toru Nakano, Kei Tashiro, and Tasuku Honjo. "ESOP-1, a secreted protein expressed in the hematopoietic, nervous, and reproductive systems of embryonic and adult mice." Blood 96, no. 1 (July 1, 2000): 362–64. http://dx.doi.org/10.1182/blood.v96.1.362.013k23_362_364.

Full text

Abstract:

To isolate soluble factors expressed in early phases of hematopoietic differentiation, we applied the signal sequence trap method to the in vitro murine hematopoietic differentiation system, in which ES cells are cocultured with OP-9 stroma cells. This strategy allowed us to isolate cDNA for a secreted protein, ESOP-1, of 160 amino acids, the sequence of which shows 64% identity with human ESOP-1/MD-2. ESOP-1 mRNA was highly expressed in the mouse embryos at 7.5 days after coitus. Expression of the ESOP-1 mRNA and protein was shown in the embryonic and adult hematopoietic system. In addition, the ESOP-1 protein was found in the yolk sac–blood islands, the developing nervous system, and the adult reproductive system. These results suggest that ESOP-1 may play some roles in the development or maintenance of hematopoietic, nervous, and reproductive systems.

APA, Harvard, Vancouver, ISO, and other styles

20

Rivas, Ana Mª, Fernando Lores, and Mª Isabel Jociles. "El anonimato y el altruismo en la donación de gametos: la producción de biocapital en la industria reproductiva." Política y Sociedad 56, no. 3 (December 12, 2019): 623–44. http://dx.doi.org/10.5209/poso.60564.

Full text

Abstract:

En este artículo analizamos de qué modo el anonimato y el altruismo de la donación de gametos desempeña una función primordial en el sostenimiento de una industria reproductiva pujante en el contexto español. A partir de nuestra experiencia etnográfica, y apoyándonos en otros datos extraídos de fuentes secundarias (estadísticas, directrices de organismos oficiales, legislación), retomamos conceptos de la teoría clásica de Marx (trabajo productivo/reproductivo, plusvalía, alienación, entre otros) para dar cuenta de la producción de biocapital a partir de los circuitos de las donaciones reproductivas. Consideramos el anonimato y el altruismo como instrumentos legales que favorecen la apropiación privada y privativa de los gametos “donados” en cantidad suficiente para el desarrollo del mercado y de la industria reproductiva. Estos instrumentos legales establecen las condiciones que hacen posible esa apropiación por parte de los centros médicos, así como la fijación de los precios y la manera en que esos gametos son “donados”.

APA, Harvard, Vancouver, ISO, and other styles

21

Kato, Keizo, Aline M. Morrison, Toru Nakano, Kei Tashiro, and Tasuku Honjo. "ESOP-1, a secreted protein expressed in the hematopoietic, nervous, and reproductive systems of embryonic and adult mice." Blood 96, no. 1 (July 1, 2000): 362–64. http://dx.doi.org/10.1182/blood.v96.1.362.

Full text

Abstract:

Abstract To isolate soluble factors expressed in early phases of hematopoietic differentiation, we applied the signal sequence trap method to the in vitro murine hematopoietic differentiation system, in which ES cells are cocultured with OP-9 stroma cells. This strategy allowed us to isolate cDNA for a secreted protein, ESOP-1, of 160 amino acids, the sequence of which shows 64% identity with human ESOP-1/MD-2. ESOP-1 mRNA was highly expressed in the mouse embryos at 7.5 days after coitus. Expression of the ESOP-1 mRNA and protein was shown in the embryonic and adult hematopoietic system. In addition, the ESOP-1 protein was found in the yolk sac–blood islands, the developing nervous system, and the adult reproductive system. These results suggest that ESOP-1 may play some roles in the development or maintenance of hematopoietic, nervous, and reproductive systems.

APA, Harvard, Vancouver, ISO, and other styles

22

Wright, R. M., and E. A. Shoesmith. "The reproductive success of pike, Esox lucius: aspects of fecundity, egg density and survival." Journal of Fish Biology 33, no. 4 (October 1988): 623–36. http://dx.doi.org/10.1111/j.1095-8649.1988.tb05505.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Yuan, Hsiao-Wei, Mark Liu, and Sheng-Feng Shen. "Joint Nesting in Taiwan Yuhinas: A Rare Passerine Case." Condor 106, no. 4 (November 1, 2004): 862–72. http://dx.doi.org/10.1093/condor/106.4.862.

Full text

Abstract:

AbstractJoint nesting, in which more than one pair contributes eggs to a group nest, is rare among cooperatively breeding birds. Early reports of the breeding biology of Taiwan Yuhinas (Yuhina brunneiceps) described them as joint nesters; however, these studies were preliminary and did not involve color-banded individuals. We conducted a 7-year study on the breeding biology of yuhinas. We found that the frequency of joint nesting was extremely high (90% of groups). Breeding groups were composed of two to seven adults (mode = 4). Most of the juveniles (78%) disappeared from our study site the year after they hatched. Only 6% remained in their natal groups; therefore, our study groups appeared to be composed primarily of non-kin. Within each group, there was a linear hierarchy of socially monogamous pairs. Mean reproductive skew index, as determined by microsatellite markers, was low (0.19). Alpha males had longer wings than beta males, whereas females did not show any differences in body size. Breeding group size had no significant effect on nest survival rate. Overall clutch size of the group increased while the average number of eggs laid by each pair decreased with group size. However, average number of fledged young per pair per season was similar for all group sizes. Alpha females were the major contributors during both diurnal (65% of groups) and nocturnal (77%) incubation, although beta females and males also contributed substantially toward incubation.Nidificación Grupal en Yuhina brunneiceps: un Caso Raro en Aves PaserinasResumen. La nidificación grupal, en la cual más de una pareja contribuye con huevos a un nido grupal, es muy rara entre las aves que presentan cría cooperativa. Estudios anteriores sobre la biología reproductiva de Yuhina brunneiceps describían a esta especie como con nidificación grupal; sin embargo, esos estudios eran preliminares y no involucraron individuos marcados con anillos coloreados. Realizamos un estudio de 7 años de duración sobre la biología reproductiva de Y. brunneiceps. Encontramos que la frecuencia de nidificación grupal fue extremadamente alta (90% de los grupos). Los grupos reproductivos estuvieron compuestos por dos a siete adultos (moda = 4). La mayoría de los juveniles (78%) desaparecieron del área de estudio luego de que eclosionaron. Sólo el 6% permaneció en sus grupos natales, por lo tanto los grupos estudiados parecen haber estado compuestos principalmente por individuos no emparentados. Dentro de cada grupo hubo una jerarquía lineal de parejas socialmente monógamas. La desviación reproductiva promedio, determinada por marcadores micro-satelitales, fue baja (0.19). Los machos alfa presentaron alas más largas que los machos beta, mientras que las hembras no presentaron diferencias en el tamaño corporal. El tamaño del grupo reproductivo no tuvo un efecto significativo sobre la tasa de supervivencia de los nidos. En general, el tamaño de la nidada del grupo aumentó mientras que el número promedio de huevos puestos por cada pareja disminuyó con el tamaño del grupo. Sin embargo, el número promedio de polluelos emplumados por pareja por época reproductiva fue similar para todos los tamaños de grupo. Las hembras alfa fueron las que más contribuyeron durante la incubación diurna (65% de los grupos) y la nocturna (77%), aunque las hembras y los machos beta también contribuyeron substancialmente a la incubación.

APA, Harvard, Vancouver, ISO, and other styles

24

Pompei, L., D. Pieracci, D. Giannetto, A. Carosi, C. Cauzillo, R. Dolciami, L. Ghetti, and M. Lorenzoni. "Reproductive biology of Cisalpine pike (Esox cisalpinus Bianco & Delmastro, 2011) in Lake Trasimeno (Italy)." Journal of Applied Ichthyology 33, no. 2 (February 16, 2017): 225–29. http://dx.doi.org/10.1111/jai.13294.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Ben Ammar, I., S. Milla, H. Missaoui, Y. Ledoré, F. Teletchea, and P. Fontaine. "Does constant photoperiod inhibit the onset of the reproductive cycle in northern pike (Esox lucius) males?" Fish Physiology and Biochemistry 44, no. 1 (November 4, 2017): 301–10. http://dx.doi.org/10.1007/s10695-017-0435-3.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

San Martín F., Mauricio. "Algunos aspectos experimentales sobre la actividad reproductiva." Anales de la Facultad de Medicina 35, no. 2 (October 18, 2014): 308. http://dx.doi.org/10.15381/anales.v35i2.9375.

Full text

Abstract:

Desde 1940, en que se fundó en Huancayo el Laboratorio del Instituto de Biología Andina, hemos estado interesados en estudios de fisiología de la reproducción en relación con la altura, y, a medida que progresábamos en nuestra investigación, resaltaba cada vez más la necesidad de profundizar esos trabajos, tanto en el campo de la endocrinología como de la embriología precoz, puntos que comenzamos a estudiar en 1947 con experiencias al nivel del mar y que tenían como fin el servirnos de base de comparación para futuros trabajos en la altura, pero los resultados que venimos obteniendo en estas experiencias, junto con la difusión y uso de cada vez mayor, en la práctica diaria de la medicina, no sólo de productos ganadotrópicos tanto de origen humano como equino, sino también de productos hormonales del ovario, nos ha inducido a presentar esta tesis con la esperanza que pueda ser una contribución que sirva para dilucidar conceptos en el empleo de esos productos hormonales.

APA, Harvard, Vancouver, ISO, and other styles

27

Moslemi-Aqdam, M., J. Imanpour Namin, M. Sattari, Sh Abdolmalaki, A. Bani, and B. E. A. Rochowski. "Reproductive characteristics of northern pike, Esox lucius (Actinopterygii: Esociformes: Esocidae), in the Anzali Wetland, southwest Caspian Sea." Acta Ichthyologica et Piscatoria 46, no. 4 (December 31, 2016): 313–23. http://dx.doi.org/10.3750/aip2016.46.4.05.

Full text

APA, Harvard, Vancouver, ISO, and other styles

28

Schwalme, Karl. "Reproductive and Overwintering Adaptations in Northern Pike (Esox lucius L.): Balancing Essential Fatty Acid Requirements with Dietary Supply." Physiological Zoology 67, no. 6 (November 1994): 1507–22. http://dx.doi.org/10.1086/physzool.67.6.30163909.

Full text

APA, Harvard, Vancouver, ISO, and other styles

29

Canagarajah, A. Suresh. "Critical Ethnography of a Sri Lankan Classroom: Ambiguities in Student Opposition to Reproduction through ESOL." TESOL Quarterly 27, no. 4 (1993): 601. http://dx.doi.org/10.2307/3587398.

Full text

APA, Harvard, Vancouver, ISO, and other styles

30

Macbeth, Bryan J., Hershel D. Frimer, Jorgelina R. Muscatello, and David M. Janz. "Use of portable ultrasonography to determine ovary size and fecundity non-lethally in northern pike (Esox lucius) and white sucker (Catostomus commersoni)." Water Quality Research Journal 46, no. 1 (February 1, 2011): 43–51. http://dx.doi.org/10.2166/wqrjc.2011.011.

Full text

Abstract:

The objective of this study was to investigate the feasibility of using field-based portable ultrasonography to accurately estimate ovary weight, gonadosomatic index (GSI) and fecundity in large-bodied fish species. These reproductive endpoints were estimated using ultrasound on prespawning female northern pike (Esox lucius) and white sucker (Catostomus commersoni) and compared with actual measured values determined post mortem. Using five cross-sectional ultrasound images in pike, estimated ovary weight and fecundity, but not GSI, were significantly correlated with measured values. All endpoints were overestimated by 21 to 23% using ultrasound in pike. In a subsequent experiment using 20 cross-sectional ovary images, estimated ovary weight, GSI and fecundity were significantly correlated with measured values in white sucker. Although underestimated by 5 to 12% using 20 cross-sectional images, there were no statistical differences among estimated and measured mean ovary weight, GSI and fecundity in white sucker using this approach. Based on the variances for GSI estimations in both species, power analysis indicated that the ultrasound technique could detect a 25% change in GSI using sample sizes of <20 fish. This study illustrates the utility of portable ultrasonography as a promising non-lethal technique for assessing reproductive endpoints in the field.

APA, Harvard, Vancouver, ISO, and other styles

31

Estrella Valenzuela, Gabriel. "Movilidad de población y comportamiento reproductivo: El caso de Baja California." Estudios Fronterizos, no. 29 (September 1, 1992): 57–89. http://dx.doi.org/10.21670/ref.1992.29.a02.

Full text

Abstract:

Este trabajo tiene como objetivo central evaluar el impacto indirecto que genera la inmigración hacia Baja California a través del comportamiento reproductivo de la población que, al migrar, ha cambiado su residencia habitual a la entidad. Para lograr ese objetivo, se analiza la información de las Encuestas Demográficas de Baja California de 1986 y 1990 con el modelo de los determinantes próximos de la fecundidad. Los resultados de dicho análisis muestran, por una parte, que los patrones reproductivos de la población migrante y no-migrante son c1aramentediferenciados (tanto en términos de fecundidad ilegítima como de formación de uniones, de sus prácticas anticonceptivas y de lactancia postparto), y que de ello se deriva un diferencial de fecundidad que resulta ser 17.5% superior para la población migrante en 1990. Por otra parte, los resultados también permiten estimar que, por cada tres nuevos inmigrantes que por año recibe la entidad, la inmigración acumulada aporta dos nuevos residentes con los nacimientos generados por las mujeres migrantes. Dada la magnitud que adquieren esos procesos (i.e. 59 mil nuevos habitantes por año ~ total), se concluye sugiriendo líneas generales de acción que permitan) adecuar la política de población a las condiciones específicas de Baja California

APA, Harvard, Vancouver, ISO, and other styles

32

Belova, N. V., N. G. Eme’lynova, A. P. Makeeva, and I. N. Ryabov. "The state of reproductive glands of the pike Esox lucius from water bodies of the Chernobyl trail in 1999–2004." Journal of Ichthyology 46, no. 8 (October 2006): 653–60. http://dx.doi.org/10.1134/s0032945206080121.

Full text

APA, Harvard, Vancouver, ISO, and other styles

33

Larsson, Per, Lennart Okla, and Lars Collvin. "Reproductive status and lipid content as factors in PCB, DDT and HCH contamination of a population of pike (Esox luciusL.)." Environmental Toxicology and Chemistry 12, no. 5 (May 1993): 855–61. http://dx.doi.org/10.1002/etc.5620120509.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Styrsky, Jennifer Nesbitt. "Influence of Predation on Nest-Site Reuse by an Open-Cup Nesting Neotropical Passerine." Condor 107, no. 1 (February 1, 2005): 133–37. http://dx.doi.org/10.1093/condor/107.1.133.

Full text

Abstract:

AbstractNest-site fidelity is associated with previous reproductive success in birds but is thought to be rare among territorial, open-cup nesting passerines. I investigated nest reuse decisions by Spotted Antbirds (Hylophylax naevioides) in central Panama. A quarter of all nest attempts were located at a previously used nest site, often within an extant nest structure. Within a breeding season, pairs preferred to reuse previously successful nest sites overall and were more likely to return to these sites for a consecutive nest attempt than they were to previously depredated nest sites. The fates of two nest attempts at the same location, however, were not associated with each other. The preference of Spotted Antbirds for reusing successful nests may be a short-term strategy to avoid sites recently discovered by predators, as pairs did reuse previously depredated nest sites for later nest attempts and did not prefer successful nest sites from previous breeding seasons.Influencia de la Depredación sobre la Reutilización de Sitios de Nidificación en un Ave Paserina Neotropical que Construye Nidos de Copa AbiertaResumen. La fidelidad al sitio de nidificación está asociada con el éxito reproductivo previo en las aves, pero se cree que ésta no es común entre especies Passeriformes territoriales que construyen nidos de copa abierta. En este estudio investigué las decisiones de reutilización de nidos en Hylophylax naevioides en el centro de Panamá. Una cuarta parte de todos los intentos de nidificación se ubicaron en lugares previamente empleados para nidificar, a menudo al interior de estructuras de nidificación remanentes. Dentro de una temporada reproductiva, las parejas prefirieron reutilizar sitios de nidificación exitosos en general y fueron más propensas a regresar a esos sitios para intentos de nidificación consecutivos, que a sitios en donde sus nidos fueron depredados. Sin embargo, los resultados de dos intentos de nidificación ocurridos en el mismo sitio no estuvieron asociados entre sí. La preferencia de emplear repetidamente sitios existosos podría ser una estrategia de corto plazo empleada por H. naevioides para evitar lugares recientemente descubiertos por depredadores, ya que las parejas reutilizaron sitios donde sufrieron depredación en intentos posteriores y no prefirieron lugares exitosos de estaciones reproductivas previas.

APA, Harvard, Vancouver, ISO, and other styles

35

Larsson, Per, Lennart Okla, and Lars Collvin. "REPRODUCTIVE STATUS AND LIPID CONTENT AS FACTORS IN PCB, DDT and HCH CONTAMINATION OF A POPULATION OF PIKE (ESOX LUCIUS L)." Environmental Toxicology and Chemistry 12, no. 5 (1993): 855. http://dx.doi.org/10.1897/1552-8618(1993)12[855:rsalca]2.0.co;2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

36

Morgan, D. H., and S. B. Tritton. "Mapping The Sky - Surveys With Schmidt Telescopes." Symposium - International Astronomical Union 133 (1988): 349–57. http://dx.doi.org/10.1017/s0074180900139816.

Full text

Abstract:

This paper describes the sky surveys carried out over the past 30 years by the three large Schmidt Telescopes; the Palomar 1.2m Schmidt, the ESO 1m Schmidt and the UK 1.2m Schmidt. Developments in photographic technology, the reproduction of the surveys as sky atlases and problems associated with the storage of original plates are discussed. Brief reference is also made to limited purpose surveys which often address one specific research problem and to possible future developments in this branch of astronomy.

APA, Harvard, Vancouver, ISO, and other styles

37

Arlinghaus, Robert, Shuichi Matsumura, and Ulf Dieckmann. "ORIGINAL ARTICLE: Quantifying selection differentials caused by recreational fishing: development of modeling framework and application to reproductive investment in pike (Esox lucius )." Evolutionary Applications 2, no. 3 (July 31, 2009): 335–55. http://dx.doi.org/10.1111/j.1752-4571.2009.00081.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

38

Díaz, Elvira Sánchez, Margarita Antonia Villar Luis, Goolan Hussein Rassol, and Sandra Cristina Pillon. "Análisis prospectivo de la enseñanza de prevención de consumo de alcohol y salud reproductiva en facultades/escuelas de educación de Lima-Perú. 2003-2004." Revista Latino-Americana de Enfermagem 13, spe (October 2005): 854–62. http://dx.doi.org/10.1590/s0104-11692005000700013.

Full text

Abstract:

El estudio trata de la enseñanza de contenidos de prevención al uso de alcohol y de salud reproductiva en cuatro facultades/escuelas de educación en Lima-Perú. Participaron 123 personas: autoridades docentes, profesores, alumnos y ex-alumnos. El instrumento de recolección de datos de análisis prospectivo, fue elaborado y validado por la Organización Panamericana de la Salud, adaptado para el estudio, se seleccionaron 40 indicadores de Salud reproductiva y 32 para prevención de uso de alcohol, distribuidos en 4 elementos básicos: contexto, estructura, función e integralidad, cada uno de ellos sometidos a tres escenarios cuyas situaciones se definen en un continuo de estabilidad hasta transformación. Considerando esos escenarios, los resultados indican haber cambios moderados de diversos grados en los indicadores (consecuentemente en los dos temas) presentes en los 4 elementos, aunque se identifique la tendencia de situación estable, representativa de manutención de perspectivas y acciones tradicionales.

APA, Harvard, Vancouver, ISO, and other styles

39

Rakauskas, Vytautas, Tomas Virbickas, Saulius Stakėnas, and Andrius Steponėnas. "The use of native piscivorous fishes for the eradication of the invasive Chinese Sleeper, Perccottus glenii." Knowledge & Management of Aquatic Ecosystems, no. 420 (2019): 21. http://dx.doi.org/10.1051/kmae/2019013.

Full text

Abstract:

The chief aim of invasive species management is to prevent biological invasions by taking measures for suppressing or eradicating potential invaders. Biological control as a management tool is frequently implemented to reduce the population size, adverse ecological impacts, and dispersal of invasive species. The efficacy of biological control measures in managing the Perccottus glenii population was assessed in four small lakes of Lithuania. The biocontrol was carried out by introducing the native piscivorous fishes Esox lucius and Perca fluviatilis into the invaded water bodies for two successive reproductive seasons. The stocking of these fishes led to an instant reduction in P. glenii abundances, and the outcome of the repeated stocking was complete disappearance of the species from the water bodies investigated. Our study proves that native predator fishes can be successfully used for eradicating well-established P. glenii populations in small eutrophic lakes. We hope the current study results will contribute to developing risk-commensurate methodologies for the control of invasive P. glenii populations in small water bodies.

APA, Harvard, Vancouver, ISO, and other styles

40

Vanegas, Blanca Cecilia. "La equidad de género: Clave para la Salud Sexual y Reproductiva." Revista Colombiana de Enfermería 2, no. 2 (August 19, 2016): 29. http://dx.doi.org/10.18270/rce.v2i2.1390.

Full text

Abstract:

La inequidad de género constituye una situación que se remonta a épocas muy antiguas, y que a pesar de los grandes avances en la historia de la humanidad, no se han logrado los cambios esperados en este aspecto, lo que ha conducido a innumerables problemas, tanto para la mujer como para el hombre, la familia y la sociedad. Es por eso que, en los últimos tiempos, en el ámbito nacional e internacional, se ha convertido la salud sexual y reproductiva en un tema de gran trascendencia, propiciando nuevos enfoques para la búsqueda de la equidad de género, debido a que se reconoce que esta condición constituye un factor básico para el disfrute de los derechos humanos, el mejoramiento de la calidad de vida y el desarrollo de los pueblos.

APA, Harvard, Vancouver, ISO, and other styles

41

Penalva-Leal, María. "La Mujer Consumible: #vaginasdesdentatas." Ciencia, Técnica y Mainstreaming Social, no. 5 (April 1, 2021): 65. http://dx.doi.org/10.4995/citecma.2021.15333.

Full text

Abstract:

Este artículo aborda cuestiones como la violencia sexual, la heteronormalización obligatoria y la denuncia la cosificación heterosexual y reproductiva de las mujeres a través de los mitos de la Vagina Dentata. Planteamos una reflexión histórica, literaria, artística y con perspectiva de género de estos mitos universales donde es misión del héroe heteronormalizar a la monstrua arrancándole los dientes para convertir esos órganos genitales en un constructo social heteronormativo usable y disfrutable por el varón. Establecemos la actualidad de este tema y vindicamos desde la investigación y la creación artística con perspectiva de género a las mujeres como personas y no como órganos reproductores o lúdicos al servicio del heteropatriarcado pasado, presente y futuro.

APA, Harvard, Vancouver, ISO, and other styles

42

Ariza, Lucía. "Cuerpos abstractos, riesgos concretos: dispositivos clínicos y la salud de las donantes de óvulos en la medicina reproductiva argentina." Salud Colectiva 12, no. 3 (October 4, 2016): 361. http://dx.doi.org/10.18294/sc.2016.789.

Full text

Abstract:

Desde una perspectiva metodológica inspirada por los estudios en ciencia y tecnología, este trabajo analiza dos dispositivos clínicos (estándares bioestadísticos y registros de donación) que se utilizan en la medicina reproductiva argentina con el objetivo de controlar el denominado “riesgo genético” que se originan en el uso de óvulos donados, así como los riesgos para la salud de las mujeres donantes. Al examinar cómo la implementación de criterios de control desatiende la especificidad de la donación de óvulos, el artículo propone que no es la ausencia de criterios y controles clínicos en fertilidad lo que produce el inadecuado control de esos riesgos, sino que es la forma concreta en la cual se implementan tales controles lo que resulta en un potencial perjuicio para la salud de las mujeres donantes.

APA, Harvard, Vancouver, ISO, and other styles

43

Shostak, Allen W., and Terry A. Dick. "Individual variability in reproductive success of Triaenophorus crassus Forel (Cestoda: Pseudophyllidea), with comments on use of the Lorenz curve and Gini coefficient." Canadian Journal of Zoology 65, no. 12 (December 1, 1987): 2878–85. http://dx.doi.org/10.1139/z87-437.

Full text

Abstract:

Maturity, mass, and lifetime fecundity were detemined in individual Triaenophorus crassus from spawning pike (Esox lucius) from Falcon Lake, Manitoba. Only 33% of worms contained eggs, and only 73% of these could release their eggs (up to 4 400 000 per worm). Inequalities in mass and fecundity were quantified using Lorenz curves and Gini coefficients calculated for worms pooled across hosts, and separately for worms in each host. Inequalities in mass were correlated with, but always lower than, corresponding inequalities in fecundity, although inequalities in fecundity and mass were more similar at high infection intensities. Consequently, inequalities in worm mass did not provide an accurate estimate of inequalities in reproductive success but could be used as an indirect index for comparative purposes. These inequalities can potentially modify parasite transmission. Ten percent of worms accounted for 85% of all parasite fecundity and, as a result of a contagious distribution of worms among pike and a lack of detectable intensity-dependent effects on parasite fecundity, 55% of worm eggs came from 10% of spawning pike. Worm numbers and distribution among hosts, maturity, and inequalities in mass and fecundity were consistent over 3–4 consecutive years, indicating that these inequalities are a normal component of the life cycle. The concentration of parasite fecundity in relatively few worms or hosts suggests that the population dynamics of T. crassus may be affected by short-term changes in parasite genotype, host activity patterns, or mortality of the few heavily infected hosts.

APA, Harvard, Vancouver, ISO, and other styles

44

Aizenberg, Lila. "Hacia una aproximación crítica a la salud intercultural." Revista Latinoamericana de Población 5, no. 9 (December 15, 2011): 49–69. http://dx.doi.org/10.31406/relap2011.v5.i2.n9.3.

Full text

Abstract:

Este artículo se ocupa de los programas de salud que incorporan la perspectiva intercultural. Se concentra en el caso del programa intercultural boliviano “extensa” y analiza cómo logra aumentar la confianza de las mujeres indígenas en los proveedores de salud de la medicina “moderna u occidental” y mejorar sus comportamientos respecto del cuidado de su salud reproductiva. Las explicaciones convencionales aplicadas al campo de la salud intercultural han atribuido el impacto de estos programas a su capacidad para “transformar” los comportamientos/valores de la población así como para “superar” la “barrera cultural” entre proveedores y usuarios/as. Sin embargo, a través de un análisis cualitativo, este estudio revela que esos programas funcionan como parte de procesos específicos en los que las mujeres entienden que pueden mitigar no solo la barrera cultural sino las múltiples barreras que las separan del sistema de salud público.

APA, Harvard, Vancouver, ISO, and other styles

45

LENHO COELHO, EDUARDO, and DALTON DE FARIA LOPES. "STUDY OF THE OBJECT HD 87643." International Journal of Modern Physics: Conference Series 18 (January 2012): 53–57. http://dx.doi.org/10.1142/s2010194512008197.

Full text

Abstract:

HD 87643 is one of the B[e] stars that still defy our understanding to better classify it. The spectroscopic observations of HD 87643 performed in the Astronomical Observatory of La Silla (ESO) between December 1998 and April 2000 show an object far more complex than was already known, with profiles of the Balmer series showing variability on different time scales. This work examine the formation of Hα and Hβ profiles with the SEI method (Sobolev approximation with Exact Integration of the transfer equation), as well as their spectral energy distribution by means of codes Cloudy and Dusty. For a homogeneous and spherically symmetric nebula around a star with T ef ~ 15, 000 K and log L/L⊙ > 4.2, the reproduction of the profiles mentioned was only achieved for Hβ and to some extent, considering two distinct regions with different laws for the expansion of the wind and with different rates of mass loss.

APA, Harvard, Vancouver, ISO, and other styles

46

Satie, Anne-Pascale, Jacques Auger, Cécile Chevrier, Cynthia Le Bon, Pierre Jouannet, Michel Samson, and Bernard Jégou. "Seminal expression of NY-ESO-1 and MAGE-A4 as markers for the testicular cancer." International Journal of Andrology 32, no. 6 (January 21, 2009): 713–19. http://dx.doi.org/10.1111/j.1365-2605.2008.00945.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Szasz, Ivonne, Olga Rojas, and José Luis Castrejón. "Desigualdad de género en las relaciones conyugales y prácticas sexuales de los hombres mexicanos / Gender Inequality in the Conjugal Relations and Sexual Practices of Mexican Men." Estudios Demográficos y Urbanos 23, no. 2 (May 1, 2008): 205. http://dx.doi.org/10.24201/edu.v23i2.1310.

Full text

Abstract:

El objetivo de este trabajo es explorar, con base en los resultados de la Encuesta de Salud Reproductiva con Población Derechohabiente del Instituto Mexicano del Seguro Social (imss) de 1998, las hipótesis que se desprenden de los estudios cualitativos. Esos estudios exploratorios sugieren importantes conexiones entre la construcción de las identidades masculinas y las prácticas anticonceptivas, de relacionamiento sexual y de prevención de las infecciones de transmisión sexual. También advierten de la existencia de marcadas diferencias generacionales y por clase social en las desigualdades de género que se expresan en las relaciones conyugales.Tomando en cuenta lo anterior, buscamos poner a prueba la hipótesis de que cuando las relaciones de género son más autoritarias en la pareja, los hombres están más expuestos a ejercer prácticas sexuales que pueden representar riesgo para la salud de ellos o sus parejas. Para ello ajustamos tres modelos de regresión logística teniendo como variables dependientes algunas que indican prácticas sexuales que pueden implicar riesgos, y revisamos si se mantiene la relación esperada al incluir la influencia conjunta de las variables indicativas de la supremacía masculina en las relaciones conyugales, así como el estrato socioeconómico y edad de los hombres estudiados. AbstractThe aim of this paper is to use the results of the Reproductive Health Survey on the Population Affiliated to the Mexican Social Security Institute to explore the hypotheses drawn from qualitative studies. These exploratory studies suggest significant connections between the construction of male identities and contraceptive practices, sexual relations and the prevention of sexually transmitted infections. They also point to the existence of marked generational and class differences in the gender inequalities expressed in conjugal relations.Bearing this in mind, we tried to test the hypothesis that when gender relations are more authoritarian within the couple, men are more inclined to engage in sexual practices that may pose a threat to their health or that of their partners. We therefore adjusted three logistic regression models, whose variable dependents included some that indicate sexual practices that may imply risks and we checked to see whether the expected relationship continued when we included the joint influence of the variables indicating male supremacy in conjugal relations as well as the socio-economic stratum and age of the men studied.

APA, Harvard, Vancouver, ISO, and other styles

48

Monk, Christopher T., Dorte Bekkevold, Thomas Klefoth, Thilo Pagel, Miquel Palmer, and Robert Arlinghaus. "The battle between harvest and natural selection creates small and shy fish." Proceedings of the National Academy of Sciences 118, no. 9 (February 22, 2021): e2009451118. http://dx.doi.org/10.1073/pnas.2009451118.

Full text

Abstract:

Harvest of fish and wildlife, both commercial and recreational, is a selective force that can induce evolutionary changes to life history and behavior. Naturally selective forces may create countering selection pressures. Assessing natural fitness represents a considerable challenge in broadcast spawners. Thus, our understanding about the relative strength of natural and fisheries selection is slim. In the field, we compared the strength and shape of harvest selection to natural selection on body size over four years and behavior over one year in a natural population of a freshwater top predator, the northern pike (Esox lucius). Natural selection was approximated by relative reproductive success via parent–offspring genetic assignments over four years. Harvest selection was measured by comparing individuals susceptible to recreational angling with individuals never captured by this gear type. Individual behavior was measured by high-resolution acoustic telemetry. Harvest and natural size selection operated with equal strength but opposing directions, and harvest size selection was consistently negative in all study years. Harvest selection also had a substantial behavioral component independent of body length, while natural behavioral selection was not documented, suggesting the potential for directional harvest selection favoring inactive, timid fish. Simulations of the outcomes of different fishing regulations showed that traditional minimum size-based harvest limits are unlikely to counteract harvest selection without being completely restrictive. Our study suggests harvest selection may be inevitable and recreational fisheries may thus favor small, inactive, shy, and difficult-to-capture fish. Increasing fractions of shy fish in angling-exploited stocks would have consequences for stock assessment and all fisheries operating with hook and line.

APA, Harvard, Vancouver, ISO, and other styles

49

Calderón Jaramillo, Mariana. "Ontologías múltiples de los cuerpos femeninos en los discursos de los derechos sexuales y reproductivos." Revista Colombiana de Sociología 40, no. 1 (January 14, 2017): 277–94. http://dx.doi.org/10.15446/rcs.v40n1.61962.

Full text

Abstract:

Este artículo recoge los planteamientos principales de un trabajo de investigación orientado por la pregunta: ¿cómo son construidos los cuerpos de las mujeres en el discurso de los derechos sexuales y reproductivos? En este sentido, se plantean diversas reflexiones respecto a las diferencias que se articulan en estas construcciones, en términos de raza, género, religión, clase, orientación sexual y localización geopolítica. Para ello, se recurrió a una metodología cualitativa, inspirada por la etnografía institucional, que presta especial atención a las formas en las que los discursos institucionales se coordinan a través de los textos, así como a los efectos de esa coordinación en la construcción de los objetos de intervención de las instituciones de planificación familiar.Se propone una revisión conceptual de las herramientas teóricas que permiten pensar el cuerpo de las mujeres, tratando de superar la tensión entre naturaleza y cultura. También, se explican los resultados de la investigación y cómo ellos son síntomas de la multiplicidad ontológica desde la que son construidos los cuerpos femeninos en los discursos analizados.Las conclusiones apuntan a demostrar que la imagen del cuerpo femenino moderno permite articular los muy diferentes modos en los que el cuerpo es construido como objeto de intervención, y cómo eso posibilita procesos de coordinación entre saberes, prácticas e instituciones, que buscan el mismo objetivo de implementar el proyecto internacionalista de los derechos sexuales y reproductivos. Así las cosas, la noción de cuerpo femenino moderno logra articular las diferencias entre el Primer y el Tercer Mundo, las tensiones entre un discurso de derechos sexuales y reproductivos y las exigencias de los deberes, la idea de un cuerpo salvado por la capacidad heroica de los médicos para implementar el proyecto de planificación familiar, y una estrategia medicalizadora que se transmite a través de los proyectos de la educación sexual.

APA, Harvard, Vancouver, ISO, and other styles

50

Tolosa, William, and Eduardo Amador Peña. "Biología de Memphis sp. (Lepidoptera: Nymphalidae): plaga potencial de la palma de aceite en la zona pacífica colombiana." Corpoica Ciencia y Tecnología Agropecuaria 7, no. 2 (January 4, 2007): 99. http://dx.doi.org/10.21930/rcta.vol7_num2_art:76.

Full text

Abstract:

En Colombia se han detectado diversas especies de insectos plaga que afectan la palma de aceite en las cuatro zonas geográficas en las cuales se encuentra establecido este cultivo permanente. Algunas prácticas de control no han sido las más adecuadas, lo que ha originado desequilibrios en los agroecosistemas que inciden sobre la entomofauna naturalmente asociada al cultivo, ocasionando el incremento de las poblaciones de insectos plaga ya conocidos y el surgimiento de especies desconocidas que, por sus hábitos alimenticios y reproductivos, deben considerarse como plagas potenciales. La aparición de Memphis sp. (Lepidoptera: Nymphalidae) en la zona productora de Tumaco (Nariño) puede representar uno de esos casos, pues muestreos foliares efectuados durante 2005 en lotes de palma de aceite de seis años de edad plantados en la Estación Experimental El Mira de Corpoica, registraron poblaciones de hasta 4 larvas/hoja que superan la baja infestación previamente reportada de 1 larva/hoja. Este trabajo se realizó para establecer la biología y hábitos de Memphis sp. en la zona de Tumaco (Nariño) y aportar al conocimiento del ciclo de vida de este insecto. Biology of Memphis sp. (Lepidoptera: Nymphalidae): a potential pest of oil palm in the western Colombian coastIn Colombia several species of insect pest affect oil palm in each of the four geographical zones where it is planted. Some management practices have not been adequately performed and agroecosystem imbalances have resulted, with negative impacts on the natural entomofauna associated to this crop, causing increases of insect pests already present and given rise to potential new pests mainly because of their feeding and reproductive habits. The report of Memphis sp. (Lepidoptera: Nymphalidae) in Tumaco (Nariño) could be such a case. Foliar surveys done on 2005 in six year old palms at the El Mira Research Station of Corpoica, reported populations of 4 larvae/leaf, an increase from the low lever infestation of 1 larvae/leaf previously reported. This study reports on the insect life cycle and the biology and habits of Memphis sp.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Esox – Reproduction'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles