On the stability of non-isothermal Bonnor-Ebert spheres. II. The effect of gas temperature on the stability

Aims. We investigate the stability of non-isothermal Bonnor-Ebert spheres with a model that includes a self-consistent calculation of the gas temperature. This way we can discard the assumption of equality between the dust and gas temperatures, and study the stability as the gas temperature changes with chemical evolution of the gas. Methods. We use a gas-grain chemical model including a time-dependent treatment of depletion onto grain surfaces, which strongly influences the gas temperature as the main coolant, CO, depletes from the gas. Dust and gas temperatures are solved with radiative transfer. For comparison with previous work, we assume that the cores are deeply embedded in a larger external structure, corresponding to visual extinction $A_{\rm V}^{\rm ext}=10$ mag. Results. We find that the critical non-dimensional radius $\xi_1$ derived here is similar to our previous work where we assumed $T_{\rm dust}=T_{\rm gas}$; the $\xi_1$ values lie below the isothermal critical value $\xi_0\sim6.45$, but the difference is less than 10%. Chemical evolution does not affect notably the stability condition of low-mass cores (<0.75 $M_\odot$). For higher masses the decrease of cooling owing to CO depletion causes substantial temporal changes in the temperature and density profiles of the cores. In the mass range 1-2 $M_\odot$ , $\xi_1$ decreases with chemical evolution, whereas above 3 $M_\odot$ , $\xi_1$ instead increases. We also find that decreasing $A_{\rm V}^{\rm ext}$ increases the gas temperature especially when the gas is chemically old, causing $\xi_1$ to increase with respect to models with higher $A_{\rm V}^{\rm ext}$. The derived $\xi_1$ values are close to $\xi_0$. The density contrast between the core center and edge varies between 8 to 16 depending on core mass and the chemical age of the gas, compared to the constant value $\sim$ 14.1 for the isothermal BES.Comment: 7 pages, 5 figures; accepted for publication in A&A; abstract (heavily) abridged for arXi

Radio continuum imaging of the R CrA star-forming region with the ATCA

The aim of this study is to investigate the nature of radio sources associated with young stellar objects (YSOs) belonging to the R CrA cluster. By combining the centimetre radio data with the wealth of shorter wavelength data accumulated recently we wish to refine estimates of the evolutionary stages of the YSOs. Fluxes and spectral indices for the brightest radio sources were derived from the observations at 3, 6, and 20 cm using the ATCA. Seven of detected sources can be assigned to YSOs, which have counterparts in the X-rays, infrared or submm. One of the YSOs, Radio Source 9, is a Class 0 candidate, and another, IRS 7B, is suggested to be in the Class 0/I transition stage. IRS 7B is associated with extended radio lobes at 6 and 20 cm. The lobes may have a gyrosynchrotron emission component, which could be understood in terms of Fermi accleration in shocks. The Class I objects detected here seem to be a mixed lot. One of these, the wide binary IRS 5, shows a negative spectral index, rapid variability, and a high degree of circular polarisation with $V/I\approx33$ % on one of the days of observation. These signs of magnetic activity suggest that at least one of the binary components has advanced beyond the Class I stage. The radio source without YSO assigment, Radio Source 5, has been suggested to be a brown dwarf. The radio properties, in particular its persistent strong emission, do not support this classification. The radio characteristics of the detected YSOs roughly agree with the scheme where the dominant emission mechanism changes with age. The heterogeneity of the Class I group can possibly be explained by a drastic decline in the jet activity during this stage, which also changes the efficiency of free-free absorption around the protostar.Comment: Accepted for publication in A&A (8 pages, 4 figures, 4 tables

“Of course Kate does everything right. We already know that”:Middleton and Markle in the British tabloids and Twitter

Abstract. Kate Middleton and Meghan Markle have recently received a lot of media attention, both in the traditional media and social media However, the reportage about the two Duchesses has been claimed biased. This thesis attempts to uncover the differences in the reportage of two British newspapers and people’s sentiments that are shared on Twitter regarding the discussion about Middleton’s and Markle’s weddings, pregnancies, and their children’s christenings. The method for analysing the research material is discourse analysis. First, ten newspaper articles written by The Daily Mail and The Daily Express will be analysed to uncover how the newspapers conceptualize the Duchesses. After that, 180 tweets will be analysed to uncover people’s sentiments about the same topics on Twitter. Finally, the way the newspapers conceptualize the Duchesses is compared to the sentiments that people express on Twitter to uncover whether differences or similarities between them are evident. Through this, the differences of traditional media and social media can be identified, which contributes to the research conducted about the media treatment of the Duchesses. This study found that the way newspapers conceptualized Middleton in the analysed newspapers is clearly more positive than the way they conceptualized Markle as all of the articles are constructed to reinforce the positive image of Middleton and the negative image of Markle. As a whole Middleton’s personal brand was noted to fit the royal family’s brand better than that of Markle’s, which is why news coverage about her is more positive. On Twitter the sentiments about the Duchesses were noted to be much more diverse than in the newspapers. Many people accepted the pro-Middleton and anti-Markle attitudes presented in the newspapers and continued to reinforce them on Twitter. However, negative sentiments and judgements were also targeted at Middleton, the royal family, media, other Twitter users and the double standards surrounding Middleton and Markle on Twitter. Such tweets were common and often expressed a pro-Markle attitude by discussing Markle’s mistreatment, which was not discussed the newspaper articles. Furthermore, no unified images of the two women exist on Twitter and as people are on the site to express their own views, a variety of sentiments about both Duchesses are apparent. In the newspapers, the range of sentiment is very narrow, despite The Daily Mail and The Daily Express being the most emotional newspapers in Britain.Tiivistelmä. Kate Middleton ja Meghan Markle ovat viime aikoina saaneet paljon huomiota mediassa ja on väitetty, että sanomalehtien uutisointi herttuattarista on ollut puolueellista. Tämän pro gradu -tutkielman tarkoituksena on tutkia miten Kate Middletonin ja Meghan Marklen häistä, raskauksista ja heidän lastensa ristiäisistä kirjoitetaan sanomalehdissä ja Twitterissä. Tarkoituksena on selvittää millaisia eroja uutismedian ja sosiaalisen median välillä ilmenee diskurssianalyysin työkaluja käyttäen. Ensimmäisenä tavoitteena on tutkia kymmentä The Daily Mail ja The Daily Express -sanomalehdissä julkaistua artikkelia ja analysoida, millaisen kuvan lehdet pyrkivät luomaan herttuattarista. Tämän jälkeen tarkastellaan 180 twiittiä ja pyritään selvittämään, millaisia mielipiteitä samat aiheet herättävät Twitter-käyttäjissä. Lopuksi sanomalehtien luomia kuvia verrataan Twitter-käyttäjien mielipiteisiin, jotta saadaan selville, onko niiden välillä eroja tai samankaltaisuuksia. Tämä edistää ymmärrystä siitä, millaisia eroja uutismedian ja sosiaalisen median välillä on herttuattaria käsittelevässä keskustelussa. Tämän tutkimuksen puitteissa saatiin selville, että sanomalehtien luoma kuva Middletonista on huomattavasti positiivisempi kuin Marklesta luotu kuva ja kaikki analysoidut artikkelit on kirjoitettu tukemaan tätä ajatusta. Herttuattarista Middletonin katsottiin sopivan paremmin kuningasperheen omaan brändiin, minkä johdosta häntä koskevat uutiset olivat positiivisempia kuin Marklesta kirjoitetut uutiset. Twitterissä naisiin kohdistuvat mielipiteet olivat puolestaan monipuolisempia kuin sanomalehdissä. Useat käyttäjät tuntuivat hyväksyvän lehtien ylläpitämän positiivisen kuvan Middletonista ja negatiivisen kuvan Marklesta. Kuitenkin myös Middleton, kuningasperhe, media, muut Twitter-käyttäjät ja herttuattariin kohdistuva kaksinaismoralismi saivat Twitterissä kritiikkiä, ei pelkästään Markle. Tällaiset twiitit olivat yleisiä ja niissä pyrittiin usein puolustamaan Marklea tuomalla esiin häneen kohdistuvaa epäreilua kohtelua, mikä erosi merkittävästi artikkeleista. Näin ollen twiiteissa Middletoniin ja Markleen kohdistuneet mielipiteet olivat huomattavasti hajanaisempia kuin artikkeleissa, joissa herttuattariin kohdistuvat mielipiteet olivat yksipuolisia, huolimatta siitä, että The Daily Mail ja The Daily Express ovat tunnetusti Britannian tunteellisimpia sanomalehtiä

Male heirs, bastard king, catholic England and other alternatives:a counterfactual history analysis of Henry VIII’s three sons

Abstract. In this thesis the lives of Henry VIII’s three sons, Prince Henry, Henry Fitzroy and Edward VI, will be analysed using counterfactual history as the research method. The aim is to research what effects them not dying prematurely might have had on England’s history and how these effects would be visible in England today. Several different alternative scenarios are introduced, and their plausibility is analysed critically. This thesis concludes that the deaths of Henry VIII’s sons altered the history of England drastically. Prince Henry’s survival would have altered history the most as him surviving would have resulted in England not going through the Protestant reformation during Henry VIII’s reign and therefore remaining Catholic. Henry Fitzroy’s role is considered to be major as he is regarded as a potential King of England, regardless of his illegitimacy. Finally, Edward VI’s survival would have resulted in a smoother transition of power and it would have saved the people of England from the religious conflicts of the 1550s. Ultimately, all the scenarios would have made the Tudor era longer and changed the way the Tudors are remembered today.Tiivistelmä. Tässä kandidaatintutkielmassa tutkitaan Englannin kuningas Henrik VIII:n kolmea poikaa, prinssi Henrikiä, Henrik Fitzroyta ja Edvard VI:ta ja heidän elämiään. Tutkimusmenetelmänä käytetään kontrafaktuaalista historiaa. Tutkielman tarkoituksena on tutkia, millaisia vaikutuksia poikien ennen aikaisella kuolemalla oli ja miten heidän selviytymisensä olisi muuttanut historiaa ja miten muutokset näkyisivät nykypäivän Englannissa. Useita eri vaihtoehtoisia skenaarioita esitellään ja niiden todennäköisyyttä analysoidaan kriittisesti. Tutkielmassa todetaan, että poikien ennenaikaisilla kuolemilla oli suuri vaikutus Englannin historiaan. Prinssi Henrikin selviäminen olisi johtanut siihen, että Englannissa ei olisi tapahtunut protestanttista reformaatiota Henrik VIII:n ollessa kuningas. Henrik Fitzroyn roolia pidetään merkittävänä ja hänet nähdäänkin potentiaalisena Englannin kuninkaana, aviottomuudestaan huolimatta. Edvard VI:n selviytyminen olisi tehnyt kruunun periytymisestä mutkattomampaa ja samalla Englanti olisi säästynyt uskonnollisilta konflikteilta 1550-luvulla. Kaiken kaikkiaan skenaarioiden lopputulema olisi ollut se, että Tudor-suvun valtakausi Englannissa olisi ollut pidempi ja se kuva, mikä ihmisillä suvusta nykyään on, olisi hyvin erilainen

Modelling line emission of deuterated H_3^+ from prestellar cores

Context: The depletion of heavy elements in cold cores of interstellar molecular clouds can lead to a situation where deuterated forms of H_3^+ are the most useful spectroscopic probes of the physical conditions. Aims: The aim is to predict the observability of the rotational lines of H_2D^+ and D_2H^+ from prestellar cores. Methods: Recently derived rate coefficients for the H_3^+ + H_2 isotopic system were applied to the "complete depletion" reaction scheme to calculate abundance profiles in hydrostatic core models. The ground-state lines of H_2D^+(o) (372 GHz) and D_2H^+(p) (692 GHz) arising from these cores were simulated. The excitation of the rotational levels of these molecules was approximated by using the state-to-state coefficients for collisions with H_2. We also predicted line profiles from cores with a power-law density distribution advocated in some previous studies. Results: The new rate coefficients introduce some changes to the complete depletion model, but do not alter the general tendencies. One of the modifications with respect to the previous results is the increase of the D_3^+ abundance at the cost of other isotopologues. Furthermore, the present model predicts a lower H_2D^+ (o/p) ratio, and a slightly higher D_2H^+ (p/o) ratio in very cold, dense cores, as compared with previous modelling results. These nuclear spin ratios affect the detectability of the submm lines of H_2D^+(o) and D_2H^+(p). The previously detected H_2D^+ and D_2H^+ lines towards the core I16293E, and the H_2D^+ line observed towards Oph D can be reproduced using the present excitation model and the physical models suggested in the original papers.Comment: 10 pages, 11 Figures; ver2: updated some of the Figures, added some references, added an entry to acknowledgement

HD depletion in starless cores

Aims: We aim to investigate the abundances of light deuterium-bearing species such as HD, H2D+ and D2H+ in a gas-grain chemical model including an extensive description of deuterium and spin state chemistry, in physical conditions appropriate to the very centers of starless cores. Methods: We combine a gas-grain chemical model with radiative transfer calculations to simulate density and temperature structure in starless cores. The chemical model includes deuterated forms of species with up to 4 atoms and the spin states of the light species H2, H2+ and H3+ and their deuterated forms. Results: We find that HD eventually depletes from the gas phase because deuterium is efficiently incorporated to grain-surface HDO, resulting in inefficient HD production on grains. HD depletion has consequences not only on the abundances of e.g. H2D+ and D2H+, whose production depends on the abundance of HD, but also on the spin state abundance ratios of the various light species, when compared with the complete depletion model where heavy elements do not influence the chemistry. Conclusions: While the eventual HD depletion leads to the disappearance of light deuterium-bearing species from the gas phase in a relatively short timescale at high density, we find that at late stages of core evolution the abundances of H2D+ and D2H+ increase toward the core edge and the disributions become extended. The HD depletion timescale increases if less oxygen is initially present in the gas phase, owing to chemical interaction between the gas and the dust predecing the starless core phase. Our results are greatly affected if H2 is allowed to tunnel on grain surfaces, and therefore more experimental data not only on tunneling but also on the O + H2 surface reaction in particular is needed.Comment: 14 pages, 12 figures, abstract abridged; accepted for publication in A &

MALDI-TOF-massaspektrometria kliinisessä mikrobiologiassa

Kuluvan vuosikymmenen aikana MALDI-TOF-massaspektrometria (matrix-assisted laser-desorption ionization time-of-flight) on mahdollistanut taudinaiheuttajabakteerien ja -sienten tunnistamisen huomattavasti nopeammin ja luotettavammin kuin biokemiallisilla menetelmillä. Kun bakteerien tunnistus biokemiallisia menetelmiä käyttäen saattaa viedä useita vuorokausia, MALDI-TOF-massaspektrometrialla tunnistus viljelymaljalla kasvavasta pesäkkeestä voidaan tehdä muutamassa minuutissa tai positiivisesta veriviljelypullosta parissakymmenessä minuutissa. Näin kliinisen mikrobiologian laboratorio pystyy antamaan bakteeriviljelyistä tunnistustuloksen hoitavalle yksikölle heti, kun viljelymaljoilla tai veriviljelypulloissa havaitaan kasvua. MALDI-TOF-massaspektrometrian merkittävimpänä rajoituksena on se, että se vaatii edeltävän malja- tai rikastusviljelyn. Lisäksi toisilleen poikkeuksellisen läheistä sukua olevat bakteerit kuten Escherichia coli ja Shigella, jotka eivät erotu toisistaan bakteeritunnistuksessa usein referenssimenetelmänä käytetyllä 16S rRNA -sekvensoinnilla, ovat vaikeita tunnistettavia myös MALDI-TOF-massaspektrometrialla

Modeling deuterium chemistry in starless cores : full scrambling versus proton hop

We constructed two new models for deuterium and spin-state chemistry for the purpose of modeling the low-temperature environment prevailing in starless and pre-stellar cores. The fundamental difference between the two models is in the treatment of ion-molecule proton-donation reactions of the form XH+ + Y -> X + YH+, which are allowed to proceed either via full scrambling or via direct proton hop, that is, disregarding proton exchange. The choice of the reaction mechanism affects both deuterium and spin-state chemistry, and in this work our main interest is on the effect on deuterated ammonia. We applied the new models to the starless core H-MM1, where several deuterated forms of ammonia have been observed. Our investigation slightly favors the proton hop mechanism over full scrambling because the ammonia D/H ratios are better fit by the former model, although neither model can reproduce the observed NH2D ortho-to-para ratio of 3 (the models predict a value of similar to 2). Extending the proton hop scenario to hydrogen atom abstraction reactions yields a good agreement for the spin-state abundance ratios, but greatly overestimates the deuterium fractions of ammonia. However, one can find a reasonably good agreement with the observations with this model by increasing the cosmic-ray ionization rate over the commonly adopted value of similar to 10(-17) s(-1). We also find that the deuterium fractions of several other species, such as H2CO, H2O, and CH3, are sensitive to the adopted proton-donation reaction mechanism. Whether the full scrambling or proton hop mechanism dominates may be dependent on the reacting system, and new laboratory and theoretical studies for various reacting systems are needed to constrain chemical models.Peer reviewe