Experimental Demonstration of Spectral Intensity Optical Coherence Tomography

We demonstrate experimentally quantum-inspired, spectral-domain intensity optical coherence tomography. We show that the technique allows for both axial resolution improvement and dispersion cancellation compared to conventional optical coherence tomography. The method does not involve scanning and it works with classical light sources and standard photodetectors. The measurements are in excellent agreement with the theoretical predictions. We also propose an approach that enables the elimination of potential artifacts arising from multiple interfaces

Geomagnetic disturbances on ground associated with particle precipitation during SC

We have examined several cases of magnetosphere compression by solar wind pressure pulses using a set of instruments located in the noon sector of auroral zone. We have found that the increase in riometric absorption (sudden commencement absorption, SCA) occurred simultaneously with the beginning of negative or positive magnetic variations and broadband enhancement of magnetic activity in the frequency range above 0.1 Hz. Since magnetic variations were observed before the step-like increase of magnetic field at equatorial station (main impulse, MI), the negative declinations resembled the so-called preliminary impulse, PI. In this paper a mechanism for the generation of PI is introduced whereby PI's generation is linked to SCA – associated precipitation and the local enhancement of ionospheric conductivity leading to the reconstruction of the ionospheric current system prior to MI. Calculation showed that PI polarity depends on orientation of the background electric field and location of the observation point relative to ionospheric irregularity. For one case of direct measurements of electric field in the place where the ionospheric irregularity was present, the sign of calculated disturbance corresponded to the observed one. High-resolution measurements on IRIS facility and meridional chain of the induction magnetometers are utilized for the accurate timing of the impact of solar wind irregularity on the magnetopause

Journal Staff

Multi-decadal studies of community and ecosystemdynamics are rare; however, this time frame is most relevant for assessing the impact of anthropogenic influences and climate change on ecosystems. For this reason, we investigated changes in vegetation and microtopography over 52 years in two contrasting mire ecosystems, one ombrotrophic (bog) and one minerotrophic (fen), representing different successional stages and contrasting hydrological settings. In both peatlands, floristic composition was recorded in the same permanent plots (n = 55-56, 0.25 m(2)) in both 1960 and 2012 and microtopography was mapped over a large area (ca. 2500 m(2)) that encompassed these same plots. We quantified and compared the community-level changes and internal spatial dynamics, tested associations between pH/microtopography and community/species change, and examined how the area and location of hummock microforms had changed over time. The bog exhibited little site level change in vegetation, where few species changed significantly in cover and plot frequency. However, detailed analyses revealed some large within-plot changes over time in the bog, illustrating that bogs can be highly dynamic systems at a fine scale. In contrast, the rich fen experienced a clear directional change; specifically, bryophyte abundance decreased by 70% and brown mosses were almost extinct. Although pH had decreased over time at the rich fen, this decrease at the plot-level was not associated with the decline of brown moss abundance. The microtopographic structure did not change substantially at the bog where similar to 70% was covered by lawn/hummocks; however, in the rich fen hummocks expanded (from 10% to 16% cover) and moved or expanded down slope. Our study suggests, that at the site-level, the bog ecosystem was more resistant to environmental changes over time compared to the rich fen, as evidenced by shifts in vegetation and microtopography. The contrasting scales of vegetation dynamics observed within a bog (i.e., within-plot changes vs. site-level) indicate that plant-environment feedbacks contribute to the peatland level stability. While in rich fens, internal feedbacks may be weaker and the ecosystem's vegetation and microtopographic structure are vulnerable to shifting hydrological fluxes

Teacher Education in the Arctic

Peer reviewedPublisher PD

Proceedings of the Morpho Challenge 2010 Workshop

In natural language processing many practical tasks, such as speech recognition, information retrieval and machine translation depend on a large vocabulary and statistical language models. For morphologically rich languages, such as Finnish and Turkish, the construction of a vocabulary and language models that have a sufficient coverage is particularly difficult, because of the huge amount of different word forms. In Morpho Challenge 2010 unsupervised and semi-supervised algorithms are suggested to provide morpheme analyses for words in different languages and evaluated in various practical applications. As a research theme, unsupervised morphological analysis has received wide attention in conferences and scientific journals focused on computational linguistic and its applications. This is the proceedings of the Morpho Challenge 2010 Workshop that contains one introduction article with a description of the tasks, evaluation and results and six articles describing the participating unsupervised and supervised learning algorithms. The Morpho Challenge 2010 Workshop was held at Espoo, Finland in 2-3 September, 2010.reviewe

The Importance of Reindeer in Northern Finland during World War II (1939–45) and the Post-War Reconstruction

We studied the consequences of World War II (WWII, 1939–45) for reindeer herding in northern Finland, evaluated the significance of the livelihood for the population during and after the war, and identified the factors that made successful reconstruction of the livelihood possible. The study is based on qualitative content analysis of articles published in the professional journal Poromies (‘Reindeer Herder’) during the period 1931–67. Reindeer were an important source of food, transport, clothing, footwear, and skins for soldiers during the war. Approximately 220 000 reindeer were slaughtered to provide food, averting the compulsory slaughter of 88 000 cows. Herders’ skills were highly valued during the war. The herds and herders figured in the reconstruction of northern Finland and contributed to the war reparations owed the Soviet Union. During the period 1939–45 the number of reindeer fell dramatically, and the cession of Finnish territories to the Soviet Union and destruction of fences made herding difficult. In addition, the area of pastureland available to reindeer decreased. The combined effects of military operations, a labour shortage, an increased number of predators, and difficult weather and snow conditions led to losses of reindeer. The recovery of the livelihood to its pre-war level took 10 years. We argue that in addition to improved post-war pasture conditions—a result of decreased reindeer densities and favourable weather—the rapid recovery of reindeer herding can be attributed to the high motivation, diligence, and experiential knowledge of herders and the herding administration gained in rebuilding the livelihood after WWI (1914–18). Both groups understood that in northern Finland it would be economically wiser to invest in reindeer husbandry rather than cattle farming since reindeer are better adapted than cattle to the harsh climate and to forage grown in low-productive soils. Reindeer herding was based on natural pastures and labour, whereas cattle farming relied on crop cultivation, as well as expensive buildings, machinery, and fertilizers.Nous avons étudié les conséquences de la Deuxième Guerre mondiale (1939–1945) sur l’élevage des rennes dans le nord de la Finlande, évalué l’importance des moyens de subsistance de la population pendant et après la guerre et déterminé les facteurs permettant la reconstruction réussie des moyens de subsistance. L’étude est basée sur une analyse du contenu qualitatif d’articles publiés dans la revue professionnelle Poromies (« éleveur de rennes ») entre 1931 et 1967. Les rennes étaient une source importante de nourriture, de transport, de vêtements, de chaussures et de peaux pour les soldats durant la guerre. Environ 220 000 rennes se sont fait abattre pour fournir de la nourriture, évitant l’abattage obligatoire de 88 000 vaches. Les compétences des éleveurs étaient très recherchées pendant la guerre. Les troupeaux et les éleveurs ont joué un rôle dans la reconstruction du nord de la Finlande et contribué aux réparations de guerre pour dommages causés à l’Union soviétique. De 1939 à 1945, on a assisté à un déclin très important de la population de rennes; la cession des territoires finlandais à l’Union soviétique et la destruction de clôtures ont rendu l’élevage difficile. De plus, les zones de pâturage des rennes ont diminué. Les effets des opérations militaires alliés à la pénurie de main-d’oeuvre, à l’augmentation du nombre de prédateurs, aux conditions météorologiques difficiles et aux conditions de la neige ont entraîné la perte de rennes. Le rétablissement des moyens de subsistance à leur niveau d’avant-guerre a pris dix ans. Nous soutenons qu’en plus de l’amélioration des conditions de pâturage d’après-guerre (le résultat du déclin de la densité de population de rennes et de conditions météorologiques favorables), le rétablissement rapide de l’élevage de rennes peut être attribué au niveau de motivation élevé, à la diligence et aux connaissances acquises par l’expérience des éleveurs ainsi qu’à l’administration des troupeaux découlant de la reconstruction des moyens de subsistance après la Première Guerre mondiale (1914–1918). Les deux groupes ont compris que pour le nord de la Finlande, il coûterait moins cher d’investir dans les activités d’élevage de rennes plutôt que dans les activités d’élevage des bovins, car les rennes s’adaptent mieux que les bovins au climat rigoureux et au fourrage qui pousse dans les sols moins productifs. L’élevage de rennes reposait sur les pâturages naturels et le travail, tandis que l’élevage des bovins reposait sur la culture des plantes, sans compter les bâtiments, la machinerie et les engrais coûteux

EU Peatlands: Current Carbon Stocks and Trace Gas Fluxes

Peatlands in Europe has formed a significant sink for atmospheric CO2 since the last glacial maximum. Currently they are estimated to hold ca. 42 Gt carbon in the form of peat and are therefore a considerable component in the European carbon budget. Due to the generally wet soil conditions in peatlands they are also significant emitters of the strong greenhouse gas (GHG) methane (CH4) and in some cases also of nitrous oxide (N2O). The EU funded CarboEurope-GHG Concerted Action attempts to develop a reliable and complete greenhouse gas budget for Europe and this report aims to provide a review and synthesis of the available information about GHG exchanges in European peatlands and their underlying processes. A best estimate for all the European countries shows that some are currently sinks for atmospheric CO2 while others are sources. In contrast, for CH4 and N2O, only the sources are relevant. Whilst some countries are CO2 sinks, all countries are net GHG emitters from peatlands. The results presented, however, carry large uncertainties, which cannot be adequately quantified yet. One outstanding uncertainty is the distribution of land use types, particular in Russia, the largest European peat nation. The synthesis of GHG exchange, nevertheless, indicates some interesting features. Russia hosts an estimated 41% of European peatlands and contributes most to all GHG exchanges (CO2: 25%, CH4: 52%, N2O: 26%, Total: 37%). Germany is the second-largest emitter (12% of European total) although it contains only 3.2% of European peatlands. The reason is the use of most of the peatland area for intensive cropland and grassland. The largest CO2 emitters are countries with large agricultural peatland areas (Russia, Germany, Belarus, Poland), the largest N2O emitters are those with large agricultural fen areas (Russia, Germany, Finland). In contrast, the largest CH4 emitters are concentrated in regions with large areas of intact mires, namely Russia and Scandinavia. High average emission densities above 3.5 t C-equiv. ha-1 are found in the Southeast Mediterranean, Germany and the Netherlands where agricultural use of peatlands is intense. Low average emission densities below 0.3 t C-equiv. ha-1 occur where mires and peatland forests dominate, e.g. Finland and the UK. This report concludes by pointing at key gaps in our knowledge about peatland carbon stocks and GHG exchanges which include insufficient basic information on areal distribution of peatlands, measurements of peat depth and also a lack of flux datasets providing full annual budgets of GHG exchanges

The interaction of labor markets and inflation: analysis of micro data from the International Wage Flexibility Project

Inflation can “grease” the wheels of economic adjustment in the labor market by relieving the constraint imposed by downward nominal wage rigidity, but not if there is also substantial downward real wage rigidity. At the same time, inflation can throw “sand” in the wheels of economic adjustment by degrading the value of price signals. A number of recent studies suggest that wage rigidity is much more important for business cycles and monetary policy than previously believed (see Erceg, Henderson and Levin, 2000, Smets and Wouters, 2003, and Hall, 2005). Thus, our results on how wage rigidity and other labor market imperfections vary between countries and how they are affected by the rate of inflation should be of considerable value in formulating monetary policy and conducting related research.

How wages change: micro evidence from the International Wage Flexibility Project

How do the complex institutions involved in wage setting affect wage changes? The International Wage Flexibility Project provides new microeconomic evidence on how wages change for continuing workers. We analyze individuals’ earnings in 31 different data sets from sixteen countries, from which we obtain a total of 360 wage change distributions. We find a remarkable amount of variation in wage changes across workers. Wage changes have a notably non-normal distribution; they are tightly clustered around the median and also have many extreme values. Furthermore, nearly all countries show asymmetry in their wage distributions below the median. Indeed, we find evidence of both downward nominal and real wage rigidities. We also find that the extent of both these rigidities varies substantially across countries. Our results suggest that variations in the extent of union presence in wage bargaining play a role in explaining differing degrees of rigidities among countries. JEL Classification: E3, J3, J5Downward nominal wage rigidity, Downward real wage rigidity, Wage change distributions, Wage setting