astronomy

Grethe Rytter Hasle

Grethe Rytter Hasle is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Grethe Rytter Hasle rather than just read about it. In short: Grethe Berit Rytter Hasle (3 January 1920 – 9 November 2013) was a Norwegian planktologist. Among the first female professors of natural science at the University of Oslo, she specialized in the study of phytoplankton.

Key takeaways

Grethe Rytter Hasle belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Grethe Rytter Hasle to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Grethe Rytter Hasle from memory before moving on to harder problems.

Reference excerpt

Grethe Berit Rytter Hasle (3 January 1920 – 9 November 2013) was a Norwegian planktologist. Among the first female professors of natural science at the University of Oslo, she specialized in the study of phytoplankton.

Personal life Hasle was born in Borre as the daughter of shipmaster Johan Kristian Rytter (1890–1966) and his wife Nicoline Olava Nielsen (1885–1976). She married Hans Martin Hasle and took his name; he died in 1971. She resided at Ekeberg in Norway and died in November 2013.

Career She graduated from Elverum Teachers' College in 1942, and graduated from the University of Oslo in 1949 where she worked with Trygve Braarud. In 1950, she published her first paper: Phototactic vertical migration in marine dinoflagellates. She took the dr.philos. degree in 1968 on the thesis An Analysis of the Phytoplankton of the Pacific Southern Ocean.

She was hired as a lecturer at the University of Oslo in 1961, and was then a professor of marine botany from 1977 to 1990. She was the third female professor at the Faculty of Mathematics and Natural Sciences, and was inducted into the Norwegian Academy of Science and Letters in 1980 as the only female researcher at the time representing the natural sciences. She was also a visiting scholar at the Texas A&M University from 1968 to 1969. She is especially known for her studies of phytoplankton in general, and specifically the class Bacillariophyceae. The Bacillariophyceae genus Haslea has been named after her. She is also known for revising the morphological taxonomy of the genera Thalassiosira, Nitzschia and Fragilariopsis. She was honored with a Festschrift for her seventieth birthday, and she received the Award of Excellence from the Phycological Society of America in 2000 and the Yasumoto Lifetime Achievement Award from the International Society for the Study of Harmful Algae in 2003.

Selected publications Hasle, Grethe R.; Fryxell, Greta A. (1970). "Diatoms: Cleaning and Mounting for Light and Electron Microscopy". Transactions of the American Microscopical Society. 89 (4): 469. doi:10.2307/3224555. JSTOR 3224555. Rytter Hasle, Grethe (1976-04-01). "The biogeography of some marine planktonic diatoms". Deep Sea Research and Oceanographic Abstracts. 23 (4): 319–IN6. Bibcode:1976DSRA...23..319R. doi:10.1016/0011-7471(76)90873-1. ISSN 0011-7471. Hasle, G. R.; Lange, C. B.; Syvertsen, E. E. (1996). "A review ofPseudo-nitzschia, with special reference to the Skagerrak, North Atlantic, and adjacent waters". Helgoländer Meeresuntersuchungen. 50 (2): 131–175. Bibcode:1996HM.....50..131H. doi:10.1007/BF02367149. ISSN 0174-3597. S2CID 23937921. Fryxell, Greta A.; Hasle, Grethe R. (1972). "Thalassiosira Eccentrica(Ehrenb.) Cleve,T. Symmetricasp. Nov., and Some Related Centric Diatoms1". Journal of Phycology. 8 (4): 297–317. doi:10.1111/j.1529-8817.1972.tb04044.x. S2CID 86683111. Lundholm, Nina; Hasle, Grethe Rytter; Fryxell, Greta A.; Hargraves, Paul E. (2002). "Morphology, phylogeny and taxonomy of species within the Pseudo-nitzschia americana complex (Bacillariophyceae) with descriptions of two new species, Pseudo-nitzschia brasiliana and Pseudo-nitzschia linea". Phycologia. 41 (5): 480–497. Bibcode:2002Phyco..41..480L. doi:10.2216/i0031-8884-41-5-480.1. ISSN 0031-8884. S2CID 85308820.

References

Worked examples

Example 1 — a first encounter with Grethe Rytter Hasle

Start with the simplest possible case. Write down what Grethe Rytter Hasle claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Grethe Rytter Hasle before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Grethe Rytter Hasle ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Grethe Rytter Hasle

In research: Grethe Rytter Hasle appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Grethe Rytter Hasle in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Grethe Rytter Hasle is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1920 births, 2013 deaths, 20th-century Norwegian women scientists, so understanding it makes those chapters shorter.
In everyday life: Look for Grethe Rytter Hasle outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Grethe Rytter Hasle in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Grethe Rytter Hasle means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Grethe Rytter Hasle out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Grethe Rytter Hasle in simple terms?

Why does Grethe Rytter Hasle matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Grethe Rytter Hasle?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Grethe Rytter Hasle.