66 research outputs found
Development of northern pike (Esox lucius) populations in the Baltic Sea, and potential effects of grey seal (Halichoerus grypus) predation
Worldwide, marine mammal populations are increasing after considerable efforts to turn the downward trends caused by hunting, accidental mortality and pollution. The ecosystem effects from the increases of these top predators may be pronounced, but are in most cases poorly known. In the Baltic Sea, the grey seal (Halichoerus grypus) has been increasing by 5-9% annually since the middle of 1980, with potential effects on fish populations, food webs and fisheries. One possible prey for the grey seal is the northern pike (Esox lucius L.), a large, predatory fish abundant in the Baltic Sea archipelagos. Rcreational fishers are experiencing declines in abundances of pike, and partly blame the decline on seal predation. To assess a potential influence of grey seal on pike population, I have analysed trends in pike abundance and size and correlate it with trends in seal abundance. In addition, I have analysed diet composition of grey seal to study what seals in the archipelago eat. To follow trends in pike abundance I have used data from the Swedish coastal fish monitoring programme and data from fishing competitions. For trends in seal abundance, I used data from the Swedish national grey seal survey. Grey seal diet was estimated from scats and stomach content collected during 2016-2020 from Uppsala County and Stockholm County, in the inner and central parts of the archipelago, i.e. the habitats where pike is most abundant.
Analyses were performed for five counties; Stockholm, Södermanland, Ăstergötland, Kalmar and Blekinge from 2000 to 2020. The fish monitoring data showed that the abundance of pike smaller than 40 cm has decreased significantly in all counties whereas the abundance of pike larger than 40 cm has decreased significantly in three counties, Stockholm, Ăstergötland, and Kalmar. The fishing competition data showed that both the abundance and the maximum size of pike have decreased significantly only in Stockholm County. Grey seal abundance has increased in all counties except Kalmar. In the grey seal diet, pike constituted 20% of the diet by weight, after perch (Perca fluviatilis) and herring (Clupea harengus). Overall, there was a negative relationship between the abundance of grey seal and the catch of both smaller and larger pike in the fish monitoring data. There was also a negative relationship between the abundance of grey seal and the maximum size of pike in Stockholm County, while no relationships between the abundance of grey seal and the maximum size of pike were observed in the other counties.
Taken together, the results from this study indicate that the increasing grey seal population is associated with the negatively development of pike population in the archipelagos of the western Baltic Sea. Management of coastal fish has traditionally only taken the effects of fishing into account. The results of this thesis emphasize the importance of a transition towards an ecosystem-based fisheries management, where the effects of increasing populations of top predators are also taken into account in the assessments, to maintain viable populations of fish.GÀddan Àr en av Sveriges viktigaste fiskart för fritidsfisket. Tack vare den
troféstorlek som gÀddan kan nÄ, i kombination med Sveriges orörda natur,
vallfÀrdar mÄnga européer Ärligen för att fÄnga just sin drömgÀdda. Men fisket efter
gÀdda i skÀrgÄrden, som en gÄng varit kÀnt som vÀrldens bÀsta, har enligt
gÀddfiskarna förÀndrats. Fisket efter gÀdda flyttas mer och mer till sjöarna, och
mÄnga gÀddfiskare förknippar förÀndringen med predation frÄn det vÀxande
grÄsÀlsbestÄndet. Syftet med min studie var att undersöka gÀddbestÄndens
utveckling lÀngs svenska kusten, och jÀmföra dessa med grÄsÀlsbestÄndets
utveckling. SÀlspillning frÄn viloplatser och maginnehÄll frÄn skjutna och sjÀlvdöda
sÀlar analyserades ocksÄ för att se vad grÄsÀlen i skÀrgÄrden Àter.
För att fÄ en bild av gÀddbestÄndens utveckling lÀngs svenska kusten analyserade
jag data frÄn nÀtprovfiske. Data fanns tillgÀngligt frÄn Stockholms lÀn till och med
Blekinge lÀn. Min analys visar att antalet gÀddor har minskat med mer Àn 90 % i
provfisken under 2000-talet, och de troféfiskar som mÄnga historier sÄ stolt berÀttar
om finns inte kvar.
Samtidigt som bestÄnden av gÀdda minskat, breder grÄsÀlen ut sig i skÀrgÄrden och
blir en allt vanligare syn i grunda innervikar, samma vikar som gÀddan trivs i.
GrĂ„sĂ€len Ă€r Ăstersjöns viktigaste toppkonsument och har just nu det största
bestÄndet pÄ lÀnge med nÀrmare 50000 individer, jÀmfört med mindre Àn 4000
individer nÀr antalet var som lÀgst. NÀr jag analyserar sambandet mellan grÄsÀlens
ökande antal och gÀddans minskande antal finns ett samband, lÀnsvisa analyser
visar pÄ ett samband i alla lÀn förutom Blekinge. Samtidigt bekrÀftar mina
dietanalyser att sett till vikt var gÀdda grÄsÀlens tredje viktigaste bytesart efter
abborre och strömming, i skÀrgÄrden i Uppsala och Stockholms lÀn.
Resultaten frÄn min studie visar att nedgÄngen av gÀdda har skett i takt med att
sÀlbestÄndet har ökat. Traditionellt sÀtt har fiskförvaltningen lÀngs kusten endast
rÀknat med fiskets uttag. Mina resultat visar pÄ vikten av att ha med effekten av
toppredatorer i förvaltningen, och övergÄ mer till att anvÀnda en sÄ kallad
ekosystembaserad fiskförvaltning. KÀnnedom om hur arter pÄverkar varandra Àr
viktig för att kunna vidta effektiva ÄtgÀrder för att stÀrka bestÄnden av rovfisk i
Ăstersjön
UtvÀrdering av bekÀmpningströsklar för bladsvampar i sockerbetor
Sockerbetor angrips av flertalet bladsvampar, bland annat Cercospora beticola, Erysiphe betae, Ramularia beticola och Uromyces betae. Erysiphe betae orsakar sjukdomen betmjöldagg medan Uromyces betae orsakar betrost. För sjukdomarna som orsakas av Cercospora beticola och Ramularia beticola finns inga bra svenska namn, men i detta arbete kommer de att benĂ€mnas âcercosporaâ respektive âramulariaâ. Mjöldagg och ramularia Ă€r tillsammans de tvĂ„ bladsjukdomar som orsakar de största och mest Ă„terkommande problemen i Sverige. Under de senaste Ă„ren har bladsvamparna och deras negativa inverkan pĂ„ sockerskörden uppmĂ€rksammats mycket i vĂ„rt land. Sockerhalten i betorna pĂ„verkas negativt genom att angripna betor sĂ€tter ny blast och resultatet av det blir att sockerskörden sjunker samtidigt som den inre betkvaliteten pĂ„verkas negativt genom att blĂ„talet höjs.
BekÀmpningsstrategierna mot bladsvampar innefattar odling av resistenta sorter och fungicidbehandlingar. De sockerbetssorter som odlas kan ha en inbyggd partiell resistens mot en eller flera sjukdomar. FastÀn de har en partiell resistens behövs fungicider för att upprÀtthÄlla höga skördar. Det finns tvÄ fungicider som Àr godkÀnda i Sverige mot bladsvampar i Sverige; Amistar och Comet. Ingen av fungiciderna har nÄgon kurativ verkan och dÀrför Àr det viktigt att göra en behandling i tid, innan angreppen blivit för starka. Det nuvarande bevakningssystemet för bladsvampar i Sverige bygger pÄ erfarenheter och försöksresultat frÄn Tyskland.
Syftet med detta examensarbete var att 1) studera angreppen av cercospora, betmjöldagg, ramularia och betrost i olika odlingsomrÄden för att fÄ mer kunskap om hur de olika sjukdomarna utvecklas under odlingssÀsongen, 2) ta fram underlag för prognoser för behandling av bladsvampar i Sverige och 3) utvÀrdera de bekÀmpningströsklar som anvÀnds i Sverige.
Angreppen av ramularia blev svaga under sÀsongen 2008, medan mjöldagg var den enskilda sjukdom som stod för de största angreppen. Rost upptrÀdde sent pÄ sÀsongen men var under den sista undersökningsveckan den sjukdom som orsakade de starkaste angreppen. Av cercospora noterades endast ett fÄtal angrepp, vilket var vÀntat eftersom klimatet i Sverige normalt inte Àr tillrÀckligt varmt för att gynna utvecklingen av denna sjukdom.
Angreppen av ramularia och rost pÄverkas till viss del av odlingsomrÄdet. Ramularia gynnas av en kort vÀxtföljd och det tillsammans med gynnsamma klimatförhÄllanden ökar risken för starka angrepp. Mjöldagg gynnas av höga kvÀvehalter i marken. I fÀlt som gödslats med stallgödsel uppvisades starkare angrepp av svampen Àr i de fÀlt som gödslats med handelsgödsel.
AngreppsnivĂ„n i de fĂ€lt som behandlades nĂ€r bekĂ€mpningströskeln var uppnĂ„dd ökade kort dĂ€refter upp till höga vĂ€rden. Detta visar pĂ„ betydelsen av att behandla fĂ€ltet sĂ„ fort bekĂ€mpningströskeln Ă€r uppnĂ„dd. Angreppen i fĂ€lt dĂ€r en behandling sattes in tidigt pĂ„ sĂ€songen förblev svaga under de följande veckorna innan de sakta började öka i storlek. I de fĂ€lt dĂ€r behandlingen utfördes senare hade bladsvamparna redan fĂ„tt chans att föröka sig och tillvĂ€xa och angreppen blev dĂ€rmed starkare. De sena behandlingarna hade endast en liten effekt pĂ„ utvecklingen av angreppen som fortsatte att öka i omfattning Ă€ven efter behandlingen. Slutsatsen Ă€r att vid behandling vid tvĂ„ tidpunkter Ă€r det viktigt att fĂ€ltet först behandlas en gĂ„ng tidigt pĂ„ sĂ€songen innan angreppen fĂ„tt chans att tillvĂ€xa, för att sedan komma med en uppföljande behandling ungefĂ€r tre veckor senare.Sugar beets are infected by several leaf pathogens, for example Cercospora beticola, Erysiphe betae, Ramularia beticola and Uromyces betae. Erysiphe betae causes the disease powdery mildew while Uromyces betae causes beet rust. For diseases caused by Cercospora beticola and Ramularia beticola there are no good Swedish names, but in this work they will be named âcercosporaâ and âramulariaâ. Powdery mildew and ramularia leaf spot are the two leaf diseases that cause the biggest and most recurring problems in Sweden. In recent years, the negative impact of leaf diseases on sugar yield has received much attention in Sweden. The sugar content is negatively affected by the production of new leaves. In addition, the internal beet quality is also negatively affected with an increasing content of amino-N.
Control strategies against leaf diseases include growing resistant varieties and fungicide treatments. The sugar beet varieties may have a partial resistance to one or more of the various diseases, but nevertheless, fungicides are necessary to maintain high yields. There are two fungicides approved in Sweden against leaf diseases in sugar beet; Amistar and Comet. None of them have any curative effect and therefore it is important to spray early, before the infection becomes to severe. The current surveillance system of leaf diseases in Sweden is based on experience and test results from Germany.
The purpose of this work was 1) to study the infections of cercospora, powdery mildew, ramularia and rust in various areas to obtain more biological information on each disease, 2) to provide data for the forecasts of the treatment of leaf fungi in Sweden and 3) evaluate the control thresholds used in Sweden.
The infections of ramularia were scarce during the season 2008. Powdery mildew was the disease that accounted for the largest attacks. Beet rust occurred late in the season and was in the final surveillance week the disease that had the highest infestation levels. Cercospora appeared only in a few fields, which was expected due to the climate in Sweden with to low temperatures for this disease.
The infections in the fields which were sprayed according to the recommended control threshold value, reached high levels shortly after treatment. This indicates the importance of spraying as soon as the threshold values is reached. Often farmers wait several days mainly of practical reasons. The infections in fields sprayed early at low infection levels remained low throughout the subsequent weeks before disease slowly began to increase. In fields treated at higher infection levels, the respective fungi already had had a chance to multiply and infect and the attacks were more severe in those fields. The late treatments only had a small effect on the disease development and disease continued to increase even after spraying. With two treatments of the crop it seems to be important to do the first treatment early in the season at a low level of infection corresponding to the threshold value, and to do the second treatment two to three weeks later.
The severities of ramularia and beet rust are affected by the specific growing area. Ramularia benefits from a short crop rotation and together with favorable climatic conditions the risk of major attacks can be increased. Powdery mildew benefits from high nitrogen levels in the soil. Beet crops that were fertilized with manure showed higher disease severities than those that were fertilized with commercial fertilizers
Sanning och konsekvens.En studie av sanningskommissionerna i Argentina och El Salvador och dess pÄverkan pÄ konsolideringen av demokratin
Sanningskommissioner Àr organ som har anvÀnts i lÀnder efter inbördes kriser för att göra upp med det förflutna, men som inte har juridisk makt. En sanningskommission kan ses som ett led i en demokratiseringsprocess och Àr sÄledes ett steg pÄ vÀgen till konsoliderad demokrati. Vi har gjort en komparativ studie mellan Argentina och El Salvador, eftersom bÄda dessa lÀnder har anvÀnt sig av varsin sanningskommission. Resultatet av kommissionernas arbete fick olika följder i de bÄda lÀnderna. I Argentina har man gÄtt vidare till domstol medan man i El Salvador tillÀmpar en amnestilag. Denna skillnad beror bla. pÄ tidsperiod, omfattning och ledarnas instÀllning till kommissionerna. Vi menar att Argentina har kommit lÀngre Àn El Salvador i konsolideringen av demokratin, och att det pekar pÄ att amnesti Àr ett sÀmre alternativ Àn domstolsförfarande för att komma till ro med ett lands historia
Prehospital Intubation and Outcome in Traumatic Brain Injury-Assessing Intervention Efficacy in a Modern Trauma Cohort.
BACKGROUND: Prehospital intubation in traumatic brain injury (TBI) focuses on limiting the effects of secondary insults such as hypoxia, but no indisputable evidence has been presented that it is beneficial for outcome. The aim of this study was to explore the characteristics of patients who undergo prehospital intubation and, in turn, if these parameters affect outcome. MATERIAL AND METHODS: Patients â„15âyears admitted to the Department of Neurosurgery, Stockholm, Sweden with TBI from 2008 through 2014 were included. Data were extracted from prehospital and hospital charts, including prospectively collected Glasgow Outcome Score (GOS) after 12âmonths. Univariate and multivariable logistic regression models were employed to examine parameters independently correlated to prehospital intubation and outcome. RESULTS: A total of 458 patients were included (nâ=â178 unconscious, among them, nâ=â61 intubated). Multivariable analyses indicated that high energy trauma, prehospital hypotension, pupil unresponsiveness, mode of transportation, and distance to the hospital were independently correlated with intubation, and among them, only pupil responsiveness was independently associated with outcome. Prehospital intubation did not add independent information in a step-up model versus GOS (pâ=â0.154). Prehospital reports revealed that hypoxia was not the primary cause of prehospital intubation, and that the procedure did not improve oxygen saturation during transport, while an increasing distance from the hospital increased the intubation frequency. CONCLUSION: In this modern trauma cohort, prehospital intubation was not independently associated with outcome; however, hypoxia was not a common reason for prehospital intubation. Prospective trials to assess efficacy of prehospital airway intubation will be difficult due to logistical and ethical considerations
Catches, bycatches and stock indicators of fisheries targeting cyprinids along the Swedish Baltic Sea coast
Decreasing abundance of many traditionally exploited fish stocks in the Baltic Sea force small-scale fisheries to find new ways to make a living. In line with Swedish national strategies on food supply there is an interest to develop commercial cyprinid fisheries. In the Bothnian Bay in the northern part of the Baltic Sea, annual catches have increased from zero-catches 2018-30 tonnes 2021. To aid a sustainable development of these cyprinid fisheries that target mainly bream (Abramis brama) and ide (Leuciscus idus), we study catch efficiency of target species and bycatch in different gears and seasons using logbook data from the Bothnian Bay. Using cameras, we also assessed bycatch rates. To assist the sustainability of the fishery we develop potential stock indicators. Our results suggests that larger gear (pound-nets) are more effective in catching bream, and that the proportion of bycatch decreased with gear size, being < 10% in the largest gear, which is similar or lower than many other Baltic Sea fisheries. By-catches of salmon is of concern in the Bothnian Bay, but the camera study indicates that salmon bycatches are sporadic. Catch per unit effort (CPUE) of bream was highest in spring and fall, and we conclude that site specific median CPUE is the most suitable stock abundance indicator. The size indicator L90, the 90th percentile of the length distribution, was similar among areas and we propose it as a suitable indicator of the demographic structure of the targeted bream stocks. Our results provide reference points for relatively unfished conditions, but as the study was based on mainly fishery dependent data, it is important to also include fishery independent data to assess ecosystem effects of a future and intensified cyprinid fishery
LÀromedel versus Kursplan - En text- och innehÄllsanalys av tvÄ lÀromedel i engelska
SYFTE OCH FRĂ
GESTĂLLNINGAR
Med utgÄngspunkt i kursplanens mÄl att uppnÄ i engelska för skolÄr nio sökte vi svar pÄ följande frÄgestÀllning:
·Hur Àr de tvÄ lÀromedlen Good Stuff och Happy uppbyggda?
·Vilka punkter ur kursplanens mÄl att uppnÄ i skolÄr nio tar dessa lÀromedel upp?
·Kan lÀrare i sin undervisning utgÄ frÄn de nÀmnda lÀromedlen för att hjÀlpa elever att nÄ upp till mÄlen i
kursplanen för skolÄr nio?
METOD
Vi valde att göra en komparativ text- och innehÄllsanalys för att svara pÄ vÄra frÄgestÀllningar. För vÄr
undersökning analyserade vi lÀromedlen, Good stuff frÄn Liber och Happy frÄn Gleerups. Dessa valde vi med
anledning av att de var relativt nya pÄ marknaden samt att de var utformade för skolÄr nio.
RESULTAT
LÀromedlen vi undersökte liknar varandra komponentmÀssigt. De bestÄr bÄda av: lÀrarhandledning, textbok,
övningsbok och cd-skivor. Det finns vissa skillnader vad gÀller layout och innehÄll. BÄde Good Stuff D och Happy
No. 3 tar till största del upp de fÀrdigheter som nÀmns i kursplanen. Det som saknas Àr frÀmst övningar dÀr
eleverna fÄr reflektera över sitt lÀrande. Fokus i de bÄda lÀromedlen ligger pÄ kommunikation och samarbete.
Vi menar att ett lÀromedel kan fungera som ett stöd och en inspiration för lÀraren, men att denne ej bör utgÄ enbart
frÄn lÀromedlet i sin sprÄkundervisning utan anpassa den efter elevgrupp och mÄlen i kursplanen. Denna insikt
kommer att pÄverka oss i vÄr framtida yrkesroll
Self- rated knowledge about hearing aids and assistive listening devices among nursing staff in communal or private nursing homes in Gothenburg
Bakgrund: HörselnedsÀttning Àr en av de vanligast förekommande kroniska sjukdomar som drabbar Àldre mÀnniskor. I Äldersgruppen 80+ har cirka 50 % en hörselnedsÀttning. MÄnga av dessa individer bor pÄ Àldreboende. DÀrför Àr det viktigt att omvÄrdnadspersonalen pÄ Àldreboenden kan hantera hörhjÀlpmedel och har kunskap inom hörselomrÄdet.
Syfte: Studiens syfte var att undersöka sjÀlvskattade kunskapsnivÄer om hantering av hörhjÀlpmedel hos omvÄrdnadspersonal pÄ Àldreboenden i Göteborgs stad samt om det fanns skillnader i sjÀlvskattad kunskap mellan olika yrkesgrupper eller mellan personal frÄn privat eller kommunalt Àldreboenden.
Material och Metod: En egenproducerad, webbaserad enkÀt anvÀndes. EnkÀten bestod av sammanlagt 24 frÄgor och pÄstÄende. I studien ingÄr 20 omvÄrdnadspersonal frÄn ÀldrevÄrden i Göteborgs stad.
Resultatet tyder pÄ ett kunskapsbehov och bristande utbildning kring hörsel och hörhjÀlpmedel inom ÀldrevÄrden i Göteborg. Studien visar att kommunens anstÀllda hade högre utbildning, lÀngre yrkeslivserfarenhet och högre poÀng pÄ sjÀlvskattningsfrÄgorna Àn de privatanstÀllda.
Slutsats: Den lÄga svarsfrekvensen pÄ 10,6 % gör att inga slutsatser kan dras utifrÄn resultatet. Studien tyder pÄ kunskapsbehov om hörsel och hörhjÀlpmedel inom ÀldrevÄrden
YRKESROLLER I RULLNING En komparativ kvantitativ studie av frilansjournalisters och anstÀllda journalisters instÀllning till att arbeta med informations-, kommunikations- och PR-uppdrag
The purpose of this study is to compare employed journalistsâ and freelance journalistsâ attitudes to work with information-, communication- and PR-assignments. Our research questions are:
What are the attitudes to work with information-, communication- and PR-assignments among employed journalists and freelance journalists?
Why are journalists willing or not willing to work with information-, communication- and PR-assignments?
What impact has the labour market on the attitude to work with information-, communication- and PR-assignments?
Has the professional journalistic identity any impact on the attitude to work with information-, communication- and PR-assignments?
To answer the questions we used different theories about the labour market and also described the journalistic ideals and the relation between information, communication, PR and journalism.
Our intention was to reach general conclusions, and we decided that the best way to answer our questions was to do a quantitative study. Therefore we made an online survey. This was also the most time- and resource-efficient way. It was sent to all reporters who worked at local stations in public service radio or public service TV. It was also sent to all reporters who worked in the daily press in the same towns as mentioned above. The survey was also sent to all the freelancers in the freelance catalogue in the same towns as above. Our survey was sent to 1158 journalists in Sweden, 566 journalists answered the survey.
The results show that freelancers are more positive to work with information-, communication- and PR-assignments than employed journalists, although journalists overall are more positive than negative. The freelancers are positive to these types of assignments mainly because of economic reasons. The employees, on the other hand, have a positive attitude mainly because this kind of business provides more work opportunities. The different attitudes of the two groups of journalists can be explained with the differentiation on the labour market. Among the employees the jobs are becoming fewer and the freelancers have a harder economic situation. A clear majority of the freelancers are willing to work with these assignments even at the same time as journalistic assignments. Among the employees, on the other hand, most of them are not willing to work with both kinds of assignments simultaneously. Furthermore, the study shows that journalists who have experience of information-, communication- and PR-assignments also are more positive than others.
The results show as well that the journalistic ideals that are associated with the profession overall are strong. They are stronger among the employees than among the freelancers. The freelancers are willing to work with information-, communication- and PR-assignments regardless of what ideals they agree with. The employees are more positive to these kinds of jobs if they to a larger extent agree to the ideals that today are less associated with the profession
Temperatur- och flödespĂ„verkan pĂ„ aspens (Leuciscus aspius) lekvandring i FyrisĂ„n och ĂrsundaĂ„n, Uppland
Interconnected freshwater habitats are essential for many fish populations, which allow fish to migrate between areas to fulfil their life-cycle and maximize their fitness. Currently, such populations are negatively affected by human habitat exploitation. As a result, the biodiversity in freshwater ecosystems is decreasing. In this study, I use data from surveys of two Asp (Leuciscus aspius) populations in Uppland to see how a representation of day length, water temperature and water current influence their spawning migrations. I also determine the difference in timing of migration between males and females, and if the individual body size matters. I found that day length, water temperature and water current affect the migratory behavior of Asp. I also found a significant difference in migratory timing between males and females, where males on average arrive 5-6 days earlier than females to spawning areas
Exploring the Diversity of Exoplanets
The search for extrasolar planets had been ongoing for many years when Mayorand Queloz discovered 51 Pegasi b in 1995. It was a giant gas planet similar to Jupiter, but with a larger radius and of only half of Jupiterâs mass. Theso called Hot Jupiter was observed to orbit its host star 7 times closer thanMercury is orbiting the Sun. Theoretical models at the time stated that gasgiants could not form in such a short distance to the host star. Thus, thisdiscovery was completely unexpected. It was the beginning of a new field ofresearch where the diversity of exoplanets is the most remarkable discovery, challenging theoretical models. Thanks to the Kepler space telescope and anew generation of space missions such as TESS, thousands of exoplanets havebeen discovered and thousands of planet candidates await confirmation. In this thesis I have studied all confirmed exoplanets to this date, which havebeen discovered by the radial velocity and/or the transit method. The planetparameters and their stellar hosts are available on NASAâs Exoplanet Archive.For all planets < 100 Mâ, I have assessed and updated the parameters for eachplanet in particular when several solutions exist. There are several types ofplanets, but the focus of this work are small planets which come in two sizes: Rocky super-Earths, and the slightly larger and lower density sub-Neptune. Different types of planets have different radii and mass ranges, which togetherwith composition and interior structure are separating the types from each other. These mass and radii ranges are however not universally defined, and in thisreport the super-Earth and sub-Neptune ranges are discussed together with their typical characteristics. The radii and mass ranges of the two different classes of small planets are overlapping and are often difficult to classify. In particularfor planets in between 2 Râ and 3 Râ, there is an ambiguity of structure and composition. This report will also investigate how planet properties depend on the stellarhost properties and on the orbital distances to the stars. One of my mainresults is that sub-Neptunes are common orbiting host stars with low metallicity, in contrast to super-Earths which are common orbiting host stars with highmetallicity. Other parameters, such as stellar effective temperature, seem to have no influence on planet properties. Super-Earthâs are found at a wide range of orbital distances while the sub-Neptunes cluster in a narrow range of orbital distances to their host star. Sub-Neptunes have an atmosphere, and are orbiting at distances where the atmosphere does not evaporate from intense host star radiation. If an atmospheree vaporates, only the rocky core of the planet is left. Thus, some super-Earths might have been sub-Neptunes that have lost their atmospheres. My second main result is that planets with characteristics of sub-Neptunes (with respect to density and interior structure) of 10 Mâ to 15 Mâ have radiibetween 2 Râ and 4.5 Râ. Sub-Neptunes in the upper mass limit, between 15Mâ to 17 Mâ, have radii from 2.6 Râ to 7.5 Râ. And finally, my third result is the relation between planet density and equilibrium temperature. The density of all planets with masses < 15 Mâ is Earth-like for equilibrium temperatures > 1400 K. For lower equilibrium temperatures corresponding to longer orbital periods, or lower-mass and cooler stars, planetswith masses < 15 Mâ have a larger spread in densities. However, it never fallsbelow a diagonal linear trend in the density against equilibrium temperature diagram described by Ï = 2.6 Ă log10(Teq) â 7.46
- âŠ