Working while enrolled in a university: Does it pay?

Working while studying at university increases the time-to-degree and may interfere with learning, but the acquired work experience may also improve employment opportunities and increase wages after the graduation. This study examines how university students' employment decisions affect their labor market success after the graduation. The study is based on an individual panel data set of Finnish university students. The data set covers the years 1987-1998, which was a period of significant changes in the Finnish labor market. The study finds that in-school work experience increases graduates' earnings at the beginning of the career, but there are no statistically significant persistent effects on employment or earnings after controlling for the selection bias in work experience acquisition.university; in-school work; earnings

The Effect of a Student Aid Reform on Graduation: A Duration Analysis

In this paper we evaluate the changes in the times-to-degree at the Finnish universities in the 1990s. In particular, we evaluate the effect of the 1992 student aid reform that was intended to shorten the duration of university studies. We find that the student aid reform had only a modest effect, and that this effect was limited to the fields with long median durations. Most of the decline in the observed times-to-degree can be explained by an increase in the unemployment rate that reduced student employment opportunities.Times-to-degree; university education; student aid; duration analysis

Gold in graphene: in-plane adsorption and diffusion

We study the bonding and diffusion of Au in graphene vacancies using density-functional theory. Energetics show that Au adsorbs preferably to double vacancies, steadily in-plane with graphene. All diffusion barriers for the complex of Au in double vacancy are above 4 eV, whereas the barriers for larger vacancies are below 2 eV. Our results support the main results of a recent experiment [Gan et al., Small 4, 587 (2008)], but suggest that the observed diffusion mechanism is not thermally activated, but radiation-enhanced.Comment: 3 pages, 3 figure

Self-passivating edge reconstructions of graphene

Planar reconstruction patterns at the zigzag and armchair edges of graphene were investigated with density functional theory. It was unexpectedly found that the zigzag edge is metastable and a planar reconstruction spontaneously takes place at room temperature. The reconstruction changes electronic structure and self-passivates the edge with respect to adsorption of atomic hydrogen from molecular atmosphere.Comment: 4 pages, 4 figures, 1 tabl

Efficient approach for simulating distorted materials

The operation principles of nanoscale devices are based upon both electronic and mechanical properties of materials. Because these properties can be coupled, they need to be investigated simultaneously. At this moment, however, the electronic structure calculations with custom-made long-range mechanical distortions are impossible, or expensive at best. Here we present a unified formalism to solve exactly the electronic structures of nanomaterials with versatile distortions. We illustrate the formalism by investigating twisted armchair graphene nanoribbons with the least possible number of atoms. Apart from enabling versatile material distortions, the formalism is capable of reducing computational costs orders of magnitude in various areas of science and engineering.Comment: 4 pages, 2 figures, 2 table

Conductance through atomic point contacts between fcc(100) electrodes of gold

Electrical conductance through various nanocontacts between gold electrodes is studied by using the density functional theory, scalar-relativistic pseudopotentials, generalized gradient approximation for the exchange-correlation energy and the recursion-transfer-matrix method along with channel decomposition. The nanocontact is modeled with pyramidal fcc(100) tips and 1 to 5 gold atoms between the tips. Upon elongation of the contact by adding gold atoms between the tips, the conductance at Fermi energy E_F evolves from G ~ 3 G_0 to G ~ 1 G_0 (G_0 = 2e/h^2). Formation of a true one-atom point contact, with G ~ 1 G_0 and only one open channel, requires at least one atom with coordination number 2 in the wire. Tips that share a common vertex atom or tips with touching vertex atoms have three partially open conductance channels at E_F, and the symmetries of the channels are governed by the wave functions of the tips. The long 5-atom contact develops conductance oscillations and conductance gaps in the studied energy range -3 < E-E_F < 5 eV, which reflects oscillations in the local density of electron states in the 5-atom linear "gold molecule" between the electrodes, and a weak coupling of this "molecule" to the tips

Formation and propagation of great salinity anomalies

North Atlantic/Arctic ocean and sea ice variability for the period 1948–2001 is studied using a global Ocean General Circulation Model coupled to a dynamic/thermodynamic sea ice model forced by daily NCEP/NCAR reanalysis data [Kalnay et al., 1996]. Variability of Arctic sea ice properties is analysed, in particular the formation and propagation of sea ice thickness anomalies that are communicated via Fram Strait into the North Atlantic. These export events led to the Great Salinity Anomalies (GSA) of the 1970s, 1980s and 1990s in the Labrador Sea (LS). All GSAs were found to be remotely excited in the Arctic, rather than by local atmospheric forcing over the LS. Sea ice and fresh water exports through the Canadian Archipelago (CAA) are found to be only of minor importance, except for the 1990s GSA. Part of the anomalies are tracked to the Newfoundland Basin, where they enter the North Atlantic Current. The experiments indicate only a minor impact of a single GSA event on the strength of the North Atlantic Thermohaline Circulation (THC)

A Potts Neuron Approach to Communication Routing

A feedback neural network approach to communication routing problems is developed with emphasis on Multiple Shortest Path problems, with several requests for transmissions between distinct start- and endnodes. The basic ingredients are a set of Potts neurons for each request, with interactions designed to minimize path lengths and to prevent overloading of network arcs. The topological nature of the problem is conveniently handled using a propagator matrix approach. Although the constraints are global, the algorithmic steps are based entirely on local information, facilitating distributed implementations. In the polynomially solvable single-request case the approach reduces to a fuzzy version of the Bellman-Ford algorithm. The approach is evaluated for synthetic problems of varying sizes and load levels, by comparing with exact solutions from a branch-and-bound method. With very few exceptions, the Potts approach gives legal solutions of very high quality. The computational demand scales merely as the product of the numbers of requests, nodes, and arcs.Comment: 10 pages LaTe

Consuming the lone volcano

Kawah Ijen is the picturesque crater of the Ijen volcano located in Eastern Java, Indonesia. However, it is not just any volcano crater, as it happens to be the locus of labour-intensive sulphur mining operation. Each day up to 15 tons of sulphur is extracted from the Ijen crater by the 350 men working as manual miners. These men carry even 100 kilogram loads of sulphur out from the crater with bare brawn and the work is with no doubt burdensome. Kawah Ijen's natural beauty has also caught the interest of tourists', and the crater has become commodified as a tourism destination, visited by hundreds of international tourists each day. Thus the storyline of this master's thesis is two-fold. The first research objective scrutinizes the Kawah Ijen sulphur mine from a commodity chain perspective, emphasizing the tough work the sulphur miners have to bear in order to satisfy the needs of the consumers at the end of the chain. The second, and the essential objective of this research in turn interrogates how the presence of the sulphur miners has become also an inevitable part of the Kawah Ijen tourism experience. In this the aspiration is to elucidate how the sulphur miners have become aestheticized as a Global South tourism attraction. In other words, this research aims to interrogate the peculiarity of this reality, by exploring how both trade and culture, and human and commodity mobilities are entangled and enshrouded within the crater of the Ijen volcano. In human geography, a research framework of 'Follow the thing' has been adopted by scholars in order to study the geographically far-flung production chains of consumer goods. As a framework it aims to make critical political-economic connections between the consumers and distant, and often also underprivileged, producers. In this Marxist-influenced undertaking emphasis is placed particularly on commodity fetishism. This notion has been mobilized to illuminate how consumers have become alienated from the means of production, in their symbolically-laden everyday consumption. As sulphur is a raw material needed in the production processes of many goods such as white sugar, fertilizers, medicines, and rubber, this research shows how these commodities were 'followed' into their origins to this particular sulphur mine. During a period of field work, a method of participant observation was utilized to get contextual understanding of this production site. The initial research objective is therefore to make connections and create awareness of the inequalities within commodity production networks. In the final research objective of this master's thesis, a postcolonial approach is mobilized to critically interrogate this initial setting, in which the miners are seen as poor and stagnant producers. Thus the Kawah Ijen tourists are taken under lens in order to gain understanding of this touristic encounter nuanced with cross-cultural and socio-economic differences between the tourists and the miners. Therefore the setting of Kawah Ijen will not only be observed as a place of production, but also as a site - and object - of consumption. By analysing blogged travel stories written by the tourists themselves, this research aims to illuminate what the tourism experience of the Kawah Ijen is about in the realm of consumption. Special attention is given to how the encounter with sulphur miners has become a constitutive part of the adventurous and authentic tourism experience of Kawah Ijen. The blog post analysis on the Kawah Ijen tourism narrative shows how the imaginaries of the sulphur miner as the 'Other' are adhered to, as the tourists construct their travel identities, make meaning of their experiences and finally represent their experience to the outside world. Finally this research aims to make ruptures to Global South fetishism by elucidating how the Kawah Ijen sulphur mine has become both commoditized and fetishized in its own right. In this fetishzation process the sulphur miners are depicted as poor and primitive, which as categories act as symbols for authentic tourism consumption in the social frameworks of the tourists. However, the aim is not to demonize the tourists, but to give recognition to the nuanced personal and social realities they are embedded in their consumption. Hence, the tourism experience of Kawah Ijen is constructed through a point of view more sensitive to the subjective negotiation of authenticity. It is argued that the Kawah Ijen tourism experience is a process in which the meaning of the experience is negotiated in a wider framework, which is vicariously embedded in postcolonial discourse. Finally, it is concluded that although there is some unequal power relations at presence in the tourism consumption of Kawah Ijen, the tourism can be the means to make more sustainable living for the miners. The leapfrog from the mining to tourism has to be only carried out in a deliberate way with respect to all of the stakeholders.Kawah Ijen on Ijenin tulivuoren kuvankaunis kraatteri, joka sijaitsee itäisellä Jaavalla Indonesiassa. Se ei ole kuitenkaan mikä tahansa tulivuorikraatteri, sillä sen sydämessä sijaitsee myös työintensiivinen rikkikaivos. Joka päivä Ijen kraatterista louhitaan jopa 15 tonnia rikkiä ja kaivosmiesten työ on kyseenalaistamatta raskasta. Kaivoksella työskentelevät 350 kaivosmiestä suorittavat työn täysin manuaalisesti, kanten kerralla jopa 100 kilogrammaa rikkiä pelkällä lihasvoimalla kraatterista. Kawah Ijenin luonnonkauneus on myös herättänyt turistien mielenkiinnon, ja kraatteri on kaupallistunut turismikohteena, ja sadat kansainväliset turistit vierailevat siellä päivittäin. Täten myös tämän ProGradu-työn tarinankulku on kahtiajakoinen. Ensimmäinen tutkimustavoite tarkastelee Kawah Ijenin rikkikaivosta tuoteketjun näkökulmasta, korostaen kuinka kaivosmiesten on siedettävä rankkaa työtä, jotta he voisivat tyydyttää ketjun loppupäässä sijaitsevien kuluttajien tarpeet. Tutkimuksen toinen, ja pääasiallinen päämäärä puolestaan kuulustelee sitä, kuinka näiden kaivosmiehien läsnäolo kraatterissa on myös vääjäämätön osa Kawah Ijenin turismielämystä. Tässä tavoitteena on selkeyttää kuinka rikkikaivosmiehet on estetisöity globaalin etelän turisminähtävyytenä. Toisin sanoen, tämä tutkimus pyrkii kuulustelemaan Kawah Ijenin todellisuuden eriskummallisuutta, tutkailemalla kuinka sekä kaupankäynti ja kulttuuri, että ihmis- ja tuotemobiliteetit ottavat tilaa haltuun Ijenin kraatterissa. Ihmismaantieteessä, monet tutkijat ovat ottaneet haltuunsa 'Follow the thing' -tutkimusviitekehyksen tutkiakseen maantieteellisesti pitkäksi venyneitä kulutustavaroiden tuotantoketjuja. Tutkimusviitekehys pyrkii tekemään kriittisiä poliittistaloudellisia kytköksiä kuluttajien ja kaukaisten, sekä usein myös vähempiosaisten, tuottajien välille. Tässä marxistisesta ajattelusta ammentaneessa tutkimustavassa painoarvoa annetaan etenkin tuotefetismille. Tämä käsite on otettu haltuun, jotta voitaisiin selkeyttää kuinka kuluttajat ovat arkipäiväisessä symbolisesti latautuneessa kulutuksen piirissään vieraantuneet tuotantotavoista. Koska rikkiä tarvitaan raaka-aineena monien tuotteiden, kuten valkoisen sokerin, lannoitteiden, lääkkeiden ja kumin, tuotantoprosesseissa, tämä tutkimus näyttää kuinka näitä tuotteita seurattiin niiden alkuperään Kawah Ijenin rikkikaivokselle. Tähän liittyvän kenttätyöjakson aikana osallistavan havainnoinnin menetelmää hyödynnettiin kontekstiin sidotun ymmärryksen saamiseksi tästä tuotantopaikasta. Tutkimuksen alustava päämäärä on kytkösten tekeminen, sekä tietoisuuden luominen tuotantoverkostojen epätasa-arvoisuudesta. Jotta voitaisiin kriittisesti kuulustella tätä alustavaa tutkimusasetelmaa, jossa kaivosmiehet nähdään köyhinä ja lamaantuneina tuottajina, tutkimuksen varsinaisessa päämäärässä hyödynnetään jälkikolonialistista lähestymistapaa. Linssin alle päätyvät Kawah Ijenin turistit, jotta voitaisiin saada syvempää ymmärrystä kulttuurillisen ja sosioekonomisen erilaisuuden sävyttämästä kohtaamisesta turistien ja kaivosmiesten välillä. Täten Kawah Ijeniä ei tarkastella vain tuotannon paikkana, mutta myös kulutuksen paikkana - ja objektina. Analysoimalla turistien kirjoittamia blogattuja matkakertomuksia, tämä tutkimus lopulta pyrkii avaamaan mistä Kawah Ijenin turismielämyksessä on kulutuksen piirissä kyse. Erityistä huomioita kiinnitetään siihen kuinka rikkikaivosmiehien kohtaamisesta on tullut oleellinen osa Kawah Ijenin seikkailumielistä ja autenttista turismielämystä. Kawah Ijenin turisminarratiivin blogitekstianalyysi näyttää kuinka Kawah Ijenin rikkikaivosmies toiseutetaan kuvitelmissa, kun turistit rakentavat matkailijaidentiteettiään, muodostavat merkityksiä kokemuksestaan ja lopulta esittävät kokemuksensa ulkopuoliselle maailmaan. Lopulta tämä tutkimus pyrkii murtamaan globaalin etelään liittyvää fetismiä valottamalla kuinka Kawah Ijenin rikkikaivos on kaupallistunut ja fetisöitynyt itsessään. Tässä fetisöintiprosesissa rikkikaivosmiehet kuvataan köyhinä ja primitiivisinä, jotka symbolisina kategorioina palvelevat autenttista turismikulutusta turistien sosiaalisessa viitekehyksessä. Tarkoituksena ei ole kuitenkaan demonisoida Kawah Ijenin turisteja, mutta antaa tunnustusta niille vivahteikkaille henkilökohtaisille ja sosiaalisille todellisuuksille, joihin he ovat kulutuksessaan upottautuneet. Näin ollen, Kawah Ijenin turismielämys jäsennetään sellaisen näkökulman kautta, joka on hienovaraisempi subjektiivista autenttisuuden neuvottelua kohtaan. Lopulta tutkimus esittää, että Kawah Ijenin turistielämys on prosessi, jossa elämyksen merkitys muodostuu laajemmassa viitekehyksessä, joka on epäsuorasti uppoutunut jälkikolonialistiseen diskurssiin. Viimeisenä johtopäätöksenä on, että vaikka Kawah Ijenin turismikulutuksessa on joitakin epätasa-arvoisia valtasuhteita läsnä, on turismilla alueella selkeä potentiaali, sillä se voi tarjota kestävämmän elinkeinon kaivosmiehille. Tämän loikkauksen kaivosteollisuudesta turismiin täytyy kuitenkin tapahtua harkitulla tavalla, jossa kaikkia osallisia kunnioitetaan