Model migration schedules incorporating student migration peaks

This paper proposes an extension of the standard parameterised model migration schedule to account for highly age-concentrated student migration. Many age profiles of regional migration are characterised by sudden ‘spiked’ increases in migration intensities in the late teenage years, which are related to leaving school, and, in particular, to entry into higher education. The standard model schedule does not appear to be effective in describing the pattern at these ages. This paper therefore proposes an extension of the standard model through the addition of a student curve. The paper also describes a relatively simple Microsoft Excel-based fitting procedure. By way of illustration, both student peak and standard model schedules are fitted to the age patterns of internal migration for two Australian regions that experience substantial student migration. The student peak schedule is shown to provide an improved model of these migration age profiles. Illustrative population projections are presented to demonstrate the differences that result when model migration schedules with and without student peaks are used.Australia, Microsoft Excel, model migration schedule, population projection, student migration

The Effect of Unresolved Contaminant Stars on the Cross-Matching of Photometric Catalogues

A fundamental process in astrophysics is the matching of two photometric catalogues. It is crucial that the correct objects be paired, and that their photometry does not suffer from any spurious additional flux. We compare the positions of sources in WISE, IPHAS, 2MASS, and APASS with Gaia DR1 astrometric positions. We find that the separations are described by a combination of a Gaussian distribution, wider than naively assumed based on their quoted uncertainties, and a large wing, which some authors ascribe to proper motions. We show that this is caused by flux contamination from blended stars not treated separately. We provide linear fits between the quoted Gaussian uncertainty and the core fit to the separation distributions. We show that at least one in three of the stars in the faint half of a given catalogue will suffer from flux contamination above the 1% level when the density of catalogue objects per PSF area is above approximately 0.005. This has important implications for the creation of composite catalogues. It is important for any closest neighbour matches as there will be a given fraction of matches that are flux contaminated, while some matches will be missed due to significant astrometric perturbation by faint contaminants. In the case of probability-based matching, this contamination affects the probability density function of matches as a function of distance. This effect results in up to 50% fewer counterparts being returned as matches, assuming Gaussian astrometric uncertainties for WISE-Gaia matching in crowded Galactic plane regions, compared with a closest neighbour match.Comment: 10 pages, 6 figures; accepted for publication in the Monthly Notices of the Royal Astronomical Societ

Australia's uncertain demographic future

The techniques of probabilistic population forecasting are increasingly being recognised as a profitable means of overcoming many of the limitations of conventional deterministic variant population forecasts. This paper applies these techniques to present the first comprehensive set of probabilistic population forecasts for Australia. We stress the disadvantages of directly inputting net migration into the cohort component model in probabilistic forecasting, and propose a gross migration flows model which distinguishes between permanent and non-permanent immigration and emigration. Our forecasts suggest that there is a two thirds probability of Australia’s population being between 23.0 and 25.8 million by 2026 and between 24.4 and 31.8 million by 2051. Comparisons with the latest official population projections of the Australian Bureau of Statistics are made.Australia, migration, migration forecasts, population forecasting, probabilistic, uncertainty

Molecular Gas Around Young Stellar Clusters

We have begun a survey of the molecular gas surrounding 31 young clusters in order to investigate the link between environment and the resulting cluster. We present here a preliminary comparison of two clusters in our sample: GGD12-15 and Mon R2. Since both clusters are located in the MonR2 molecular cloud at a distance of 830 pc, observational biases due to differing sensitivities and angular resolutions are avoided.Comment: 2 pages, 2 figures, uses newpasp.sty. To appear in "Hot Star Workshop III: The Earliest Phases of Massive Star Birth" (ed. P.A. Crowther

E-knjige: nakladnička dvojba

This paper reports on a study of publishers’ attitudes towards e-books in the context of the global situation of e-book publishing. Comparative data are drawn from a replication of a survey carried out in Sweden, in Lithuania and in Croatia. The great contrast between the rise of the e-book in English speaking countries (and those with significant English speaking readers) is shown and contrasted with that in ‘small language markets’. This three country survey reveals a number of similar responses from publishers on several key issues, i.e., self-publishing, the future role of bookshops, and relationships with public libraries. The results also reveal that publishers have certain ambivalence on these issues. The overall conclusion is that there is a marked difference in the growth of e-book publishing in small language markets compared with the English language market.Rad predstavlja istraživanje stavova nakladnika prema e-knjigama u kontekstu globalnog elektroničkog nakladništva. Dani su usporedni podatci na temelju istraživanja koja su istodobno provedena u Švedskoj, Litvi i Hrvatskoj. Prikazan je golem nerazmjer u zastupljenosti e-knjiga u zemljama engleskoga govornog područja (i onima sa značajnim brojem čitatelja engleskog jezika) i na tržištima tzv. malih jezika. Komparativno istraživanje provedeno u tri zemlje „malih jezika“ pokazalo je brojne sličnosti u stavovima nakladnika prema nekim ključnim pitanjima, npr. samostalnom objavljivanju, budućoj ulozi knjižara i odnosima s narodnim knjižnicama. Rezultati također pokazuju da nakladnici katkad imaju i proturječne stavove o pojedinim navedenim pitanjima. Opći je zaključak da postoji uočljiva razlika u porastu naklade e-knjiga na malim jezičnim tržištima u odnosu na tržišta engleskog govornog područja

Fenomen e-knjige: tehnološka prekretnica

The emergence of the e-book as a major phenomenon in the publishing industry is of interest, world-wide. The English language market, with Amazon.com as the major player in the market may have dominated attention, but the e-book has implications for many other languages and book markets. The pre-e-book publishing world can be seen as a system in which authors delivered texts to publishers, who evaluated, edited, printed and distributed the published text to bookshops and thence to libraries and individual readers. This process has been going on since Gutenberg’s re-invention of movable type in about 1439 (following its original invention in China in the 9th century, and the use of metallic type in Korea in 1234), in other words, for about the past 550 years. The invention of movable type was an instance of a disruptive technology: eventually putting monastic scribes out of business altogether. Similarly, the e-book has the potential to disrupt the processes for the production, distribution and use of authorial texts, and is already in the process of doing so. First, the phenomenon of self-publishing has emerged as a serious contender to the more formal process; secondly, publishers may derive significant economic benefit from the reduction in printing and distribution costs, as well as the ability to sell directly to the consumer through their own Websites; thirdly, the impact on booksellers may result in a further reduction in the number of independent stores – a decline already in process as a result of online bookselling; fourthly, user demand is resulting in libraries wrestling with the problems of how to manage e-books within their collection development and management processes; and, finally, the behaviour of readers is changing as the devices available for using e-books become more numerous and cheaper. Only someone blessed with absolute certainty in forecasting the future can know exactly how things will change, but there is little doubt that the development of the e-book will bring about substantial changes in the processes of book production, distribution and use – and many of these changes will surprise us.Razvoj e-knjige kao novog fenomena u nakladničkoj industriji od globalne je važnosti. Iako se najviše pozornosti pridaje tržištu engleskog govornog područja, s tvrtkom Amazon.com kao ključnim igračem, implikacije pojave e-knjige razvidne su na mnogim tržištima i na mnogim jezicima. Nakladništvo se do pojave e-knjiga moglo opisati kao sustav u kojemu su autori isporučivali tekstove nakladnicima, koji su iste tekstove vrednovali, uređivali, tiskali i distribuirali posredstvom knjižara i knjižnica sve do individualnih čitatelja. Takav se proces uobičajio od Gutenbergova vremena i traje posljednji 550-ak godina. Otkriće tiska pomičnim slovima također je primjer tehnološke prekretnice, koja je s vremenom dokinula sustav umnažanja knjiga prepisivanjem. Slično tome, potencijal e-knjige je raskidanje s uobičajenim praksama proizvodnje, distribucije i korištenja autorskog teksta, što je već postalo razvidno kroz sljedeće procese. Prvo, fenomen samostalnog objavljivanja djela postaje ozbiljna konkurencija tradicionalnom nakladništvu. Drugo, nakladnici usmjeravanjem na e-knjige mogu ostvariti veće uštede u troškovima tiska i distribucije, a stječu i mogućnost izravne prodaje knjiga kupcima posredstvom vlastitih mrežnih stranica. Treće, navedeni će razvoj dodatno smanjiti broj neovisnih knjižara, a taj je proces već otpočeo pojavom online knjižarstva. Četvrto, zahtjevi korisnika rezultiraju problemima s kojima se suočavaju knjižnice kada je riječ o organizaciji kolekcija e-knjiga i njihovu korištenju. Naposljetku, ponašanje čitatelja se mijenja budući da uređaji koji omogućuju čitanje e-knjiga postaju sve brojniji i jeftiniji. Samo bi osoba posve sigurna i pouzdana u predviđanju budućnosti mogla predvidjeti daljnji razvoj, ali jasno je da će e-knjige prouzročiti supstancijalne promjene u proizvodnji, distribuciji i korištenju knjige – a mnoge od tih promjena bi mogle biti iznenađujuće