Brage Nord Open Research Archive
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Introduction of new ISA 315 in small and mediumsized auditing firms: Improvement of auditors professional judgement or an exercise of checklists?
No full textMasteroppgave i regnskap og revisjon - Nord universitet 202
Unravelling Spermatogenesis in Spotted Wolffish: Insights from the Ultrastructure of Juvenile Male Testes to the Cryopreservation of Broodstock Sperm
Get PDFThis study aimed to deepen our understanding of the reproductive biology of male spotted wolffish (Anarhichas minor) using two different experimental approaches involving juvenile and mature broodstock fish. The first approach consisted of a detailed histological examination of the testes to identify the onset of gonadal maturation and characterize the spermatogenic stages in two- and three-year-old juvenile specimens. Light microscopy analysis revealed clear differences between the age groups. Two-year-old fish displayed well-defined interstitial tissue, Sertoli cells, and cysts housing spermatogonia stem cells in which meiosis had not yet begun. In contrast, three-year-old fish exhibited cysts containing spermatocytes, spermatids, and abundant spermatozoa, indicating the initiation of the spermatogenic cycle, albeit with asynchronous puberty. Histochemical staining revealed a significant presence of smooth myoid cells in the interstitial tissue of sexually mature fish. In contrast, electron microscopy further revealed synaptonemal complexes with chromatin differentiation and the appearance of centriolar structures. The second approach focused on optimizing semen freezing and cryopreservation procedures in mature broodstock individuals over the age of 10 years. Seven freezing extenders (KT, TS-2, OP, MT, MH, HBSS, or SR), with seawater (SW) as a control, were assessed along with two cryoprotectants dimethylsulfoxide (DMSO) or methanol to evaluate their impact on pre- and post-thaw semen quality. Results showed that the MT and HBSS extenders were superior in total sperm kinetics at 1:3 dilution and that DMSO showed optimal results in sperm motility and velocity variants. Moreover, the MT and HBSS groups demonstrated consistent sperm viability after cryopreservation, with values similar to fresh samples. Based on the viability results of the SYBR-green-14/PI assay comparing fresh and cryopreserved sperm using MT and HBSS, the MT extender emerged as the most effective freezing medium for cryopreservation of spotted wolffish broodstock sperm. In conclusion, this study provides a comprehensive understanding of the reproductive dynamics of male spotted wolffish, offering valuable insights for both scientific research and aquaculture management.publishedVersio
Inkluderende tilpasning av matematikkundervisning for flerspråklige elever: En utforskning av lærerpraksis
Get PDFMaster i grunnskolelærerutdanning 5-10. Matematikk 4 - 202
Eldre og gruppebasert trening. En kvalitativ undersøkelse av eldre som deltar på gruppebasert trening
Get PDFMasteroppgave i helsevitenskap - 202
Treningsbelastning i småbanespill: Hvordan påvirkes ulike belastningsvariabler av utfall i trelagsspill med rullering?
Get PDFMaster i kroppsøvings- og idrettsvitenskap - 202
School completion and progression to higher education in adolescents with social anxiety: a linkage between Young-HUNT3 and national educational data (2008–2019), Norway
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Hvordan kan lærere på ungdomsskoletrinnet forebygge, oppdage og hjelpe elever med matematikkangst?
Get PDFMaster i grunnskolelærerutdanning 5-10. Matematikk 4 - 202
