Wyniki wyszukiwania

1

Is ovoviviparity rightly advertised?

100%

Pokryszko B. M.

Folia Malacologica

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1998

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tom 06

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nr 1-4

2

The distribution of vitamins A, E and C in tissues of laying hens during reproductive period

100%

Kuklenko T., Ionov I., Surai P.

Zeszyty Naukowe. Przegląd Hodowlany

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1997

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tom 31

3

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Life cycle of Helicodonta obvoluta

100%

Maltz T. K.

Folia Malacologica

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1999

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tom 07

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nr 4

4

Contribution to the knowledge of biology and commercial exploitation of the Roman snail (Helix pomatia L.)

100%

Stepczak K.

Folia Malacologica

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2012

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tom 20

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nr 1

5

Reproductive traits of ducks from maternal strains in two laying periods and meat traits of their offspring

100%

Mazanowski A., Ksiazkiewicz J., Szukalski G.

Roczniki Naukowe Zootechniki

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1999

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tom 26

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nr 4

6

Reproductive traits of ducks from paternal strains in two laying periods and meat traits of their offspring

100%

Mazanowski A., Ksiazkiewicz J., Kisiel T.

Roczniki Naukowe Zootechniki

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1999

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tom 26

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nr 4

7

Thyroid hormones in the cerebrospinal fluid of the third ventricle of adult female sheep during different periods of reproductive activity

80%

Skipor J., Misztal T., Szczepkowska A.

Polish Journal of Veterinary Sciences

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2010

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tom 13

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nr 4

Thyroid hormones (THs) are obligatory for transition from breeding season to anestrus in sheep. In this process, THs act during a very limited time of the year and primarily within the brain. In ewes chronically equipped for sampling cerebrospinal fluid (CSF) from the third ventricle, we have characterized the concentrations of total and free thyroxine (T4), triiodothyronine (T3), and total reverse T3 (rT3) in the CSF during breeding season, anestrus and during a critical period required for transition to anestrus (December-March). The total T4, T3, rT3 and free T3 average concentrations (± SEM) in CSF were 1.5 ± 0.07 ng/ml, 14.5 ± 1.2 pg/ml, 43 ± 7.4 pg/ml, and 0.6 ± 0.05 pg/ml, respectively, and all were significantly lower (p < 0.001) than in blood plasma except free T4 (12.6 ± 1.1 pg/ml), which was similar to that in plasma. There was a seasonal trend (p < 0.05) in the concentration of total T3 (highest in December) and free T4 (highest in November) in the CSF that does not follow that in blood plasma. During the period of transition to anestrus the CSF total T3/TT4 molar ratio and free T3/ T4 ratio were significantly lower (p < 0.05 and p < 0.01, respectively) than in blood plasma, while the total rT3/T4 ratio was significantly higher (p < 0.01) at the end of this period (March). Additionally, the CSF total rT3 concentrations were also significantly correlated with the CSF total T4 levels (r = 0.57; p < 0.05). In conclusion, the CSF in sheep may serve as a considerable source of thyroid hormones for neuroendocrine events. The lack of significant changes in THs concentrations in the CSF during the period of transition to anestrus indicate that neither seasonal changes of THs circulating in the blood plasma nor THs circulating in the CSF actively drive the transition to anestrus.

8

Identification and structure of lampbrush sex bivalents prior to and after the reproductive period of the European domestic goose Anser anser

80%

Andraszek K., Smalec E., Tokarska W.

Folia Biologica

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2009

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tom 57

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nr 3-4

143-148

9

Potential ecological pitfalls inadvertantly produced by man at important bird sites

80%

Strawinski S.

The Ring

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1993

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tom 15

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nr 1-2

10

Seasonal variations in the occurrence of the prawns Crangon crangon [L., 1758], Palaemon adspersus [Rathke, 1837] and Palaemon elegans [Rathke, 1837] in the littoral zone of the Gulf of Gdansk

80%

Lapinska E., Szaniawska A.

Oceanological and Hydrobiological Studies

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2005

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tom 34

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nr 2

11

Population dynamics of five sigmodontine rodents of Northwestern Patagonia

80%

Guthmann N., Lozada M., Monjeau J. A., Heinemann K. M.

Acta Theriologica

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1997

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tom 42

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nr 2

Population dynamics of five rodent species were studied, from March 1991 to August 1994, in an area located in the ecotonal steppe of northwestern Patagonia, Argentina {at about 40°S). Seasonal and annual fluctuations in population numbers were found in all sigmodontine species. The reproductive period, sex ratio and longevity of the five species were also studied. Abrothrix xanthorhinus (Waterhouse, 1837), a habitat generalist, was the most abundant species. Eligmodontia morgani (Allen, 1901), Abrothrix longipilis (Waterhouse, 1837), Reithrodon auritus (Fischer, 1814) and Oligoryzomys longicaudatus (Bennett, 1832) were subdominant. The present study is a first description of the population dynamics in this rodent community, whose ecological characteristics gather importance considering that some of these species are Hantavirus reservoirs.

12

Age, reproduction, and fecundity of a population of Cobitis sp. (Actinopterygii: Cypriniformes: Cobitidae) from the Babolrud River in the southern Caspian Sea basin

61%

Mousavi Sabet H., Kamali A., Soltani M., Bani A., Esmaeili H. R., Rostami H., Vatandoust S., Moradkhani Z.

Acta Ichthyologica et Piscatoria

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2011

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tom 41

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nr 2

Background. Loach fishes, Cobitis sp., are found in the majority of streams in the southern Caspian Sea basin, but reproductive parameters of them are barely known. Reproductive conditions are key parameters of fish populations and their assessment is very important for several reasons. Therefore, the main aim of this study was to obtain reproductive characteristics of this fish which will be a first report for the basin. Materials and methods. Sampling was done at monthly intervals throughout the year and 226 individuals of Cobitis sp., were caught from the Babolrud River in the southern Caspian Sea basin, north of Iran. Age, sex ratio, fecundity, oocytes diameter, gonadosomatic- and modified gonadosomatic indices were estimated. Regression analyses were used to find relations between fecundity and fish size (length and weight), gonad weight, and age. Results. Sex ratio differed significantly from unity, and the percentage of females was greater than that of males. The mature females and males were longer than 45 and 35 mm in total length (+2 and +1 in age, respectively). The average egg diameter was 0.58 mm. The spawning took place from beginning of May to late July, when water temperature was between 19.1 and 24.6°C. Average GSI value at the beginning of the reproduction period was 8.93% and ranged between 4% and 26% in ripe, mature females. The average of absolute and relative fecundity was calculated 2172 and 590, respectively. The absolute fecundity was significantly related to body weight and gonad weight. Conclusion. Based on the pattern of gonadosomatic index, it was concluded that this fish has a prolonged active reproductive period. Their reproduction in this basin shows some differences from other reports, which might be related to different environmental conditions.

Ograniczanie wyników

Is ovoviviparity rightly advertised?

The distribution of vitamins A, E and C in tissues of laying hens during reproductive period

Life cycle of Helicodonta obvoluta

Contribution to the knowledge of biology and commercial exploitation of the Roman snail (Helix pomatia L.)

Reproductive traits of ducks from maternal strains in two laying periods and meat traits of their offspring

Reproductive traits of ducks from paternal strains in two laying periods and meat traits of their offspring

Thyroid hormones in the cerebrospinal fluid of the third ventricle of adult female sheep during different periods of reproductive activity

Identification and structure of lampbrush sex bivalents prior to and after the reproductive period of the European domestic goose Anser anser

Potential ecological pitfalls inadvertantly produced by man at important bird sites

Seasonal variations in the occurrence of the prawns Crangon crangon [L., 1758], Palaemon adspersus [Rathke, 1837] and Palaemon elegans [Rathke, 1837] in the littoral zone of the Gulf of Gdansk

Population dynamics of five sigmodontine rodents of Northwestern Patagonia

Age, reproduction, and fecundity of a population of Cobitis sp. (Actinopterygii: Cypriniformes: Cobitidae) from the Babolrud River in the southern Caspian Sea basin