Intrepid Enfantes : The Emergence of Child Soldiers in the Democratic Republic of Congo

This is a study on the emergence of child soldiers during the wars in Democratic Republic of Congo. The study challenges the common notions that children cannot end up in armed forces out of their own will, or that they are incapable of understanding properly their situation when they are making those decisions. Acknowledging their will and action is required in order to understand the processes and developments occurring in Congo, and the tactics and manoeuvrings that they engage in. The appearance of thousands of child soldiers among the numerous militias and in the national army of Congo happened against the backdrop longlasting decline in the economic and political sphere that in turn weakened the social cohesion in the Congolese families and communities. The choices of the informants in the study come to be explained through the developments in their lives, families, communities, as well as those in the society at large. In order to do that, theoretical concepts of vital conjunctures and social horizons in a moving social environment are utilized to track the developments, socially informed viewpoints, and actions taken by the child soldiers in the study. The material for the thesis comes from interviews of former child soldiers in North Kivu of DRC, and from written sources. While the informants in the study did face challenges prior and during their involvement in arms, the material shows that they did engage in positive action in order to improve their immediate and to-come prospects in a situation where the prospects for youth generally are bleak. The results also demonstrate the impact that the social and political developments during the last two decades in North Kivu had on those prospects of the informants, in part paving their way to join the militias. Those developments have also had an impact on family dynamics, causing drift between the generations and sexes in Congo. The roles and responsibilities that children have taken up as armed combatants have not been the only repercussions of the changes facing the Congolese families and communities. Child witches have challenged the notions of traditional generational dynamics as well, therefore underlining the similarities of the two phenomenon is presented in this study as well. This research indicates that despite the marginality and challenges facing up many young Congolese, they are still able to prospect towards future, and more importantly seek ways to reach those prospects on their way from youth to adulthood, even if that would mean challenging the old existing social and political order

Lake-atmosphere greenhouse gas exchange in relation to atmospheric forcing and lake biogeochemistry

Greenhouse gas (GHG) emissions from lakes result from processes between the watershed, lake characteristics and the atmosphere. The organic matter loading from the watershed both provides carbon for the lake biota and in major part defines water clarity, which, in addition to wind and heat flux, is essential in thermocline formation. Thermal stratification suppresses the wind-induced momentum input to the surface water preventing effective mixing of gases throughout the water column. The lake biota process the organic matter, producing carbon dioxide (CO2) in oxic surface water and also methane (CH4) if the near-bottom water becomes anoxic, and thus influence the chemical properties of the water column. Finally, air-water GHG exchange occurs over a thin layer at the water surface. Lakes are typically supersaturated with CO2 and CH4 in relation to average atmospheric mixing ratios causing fluxes of these gases to the atmosphere. Even though lakes cover only 2 % of the world s land surface, it has been estimated that lakes release about 10 % of the carbon fixed annually by the terrestrial ecosystems back to the atmosphere. A critical parameter in the gas exchange estimates is the gas transfer velocity (k), which is governed by turbulence. The implementation of direct flux measurement using the eddy covariance (EC) technique allows the detailed measurements needed to estimate k. However, on lakes, the EC method is a novel subject and as of yet, there has been no published estimates of the error related to these measurements nor fully established set of accepted procedures. The aim of this thesis was to assess the current global CO2 evasion estimates from lakes to the atmosphere by comparing parameterizations for k and the significance of wind and heat flux to the gas transfer in small lakes. To improve future predictions of gas evasion from lakes, we focused on the changes in water clarity and how they affect water column physics and processes in the air-water interface. We used the EC method for the high precision data needed, and therefore also aimed to improve the EC methodology on lakes. The air-water gas transfer was related to both wind and heat loss during times of seasonal stratification, but only to wind during autumn overturn, and the mean value for k of CO2 was 6.0 cm h-1 in Lake Kuivajärvi. When wind-induced thermocline tilting and resulting spatial variability in surface water CO2 concentrations was accounted for, k derived from the measurements dropped to 5.2 cm h-1. This was still over twice the estimate (2.2 cm h-1) calculated with a widely used model for k in lakes suggesting that the global estimates of gas evasion from lakes might be underestimations. Unsolved question is that how important factor the thermocline tilting is in other lakes in defining spatial variability? Our results showed that k for CH4 was higher than for CO2, a result which has been reported in some other studies, but as of yet, no solid explanation has been found. Water clarity was a significant parameter defining the thermal stratification of the lake: a change from clear to dark water would lead to shorter stratification period and lower water column temperatures in small lakes and therefore have significant impact on the lake-atmosphere exchange processes. Important question is how changes is climate will affect lake water clarity e.g. via precipitation and runoff related DOC loading. We concluded that the EC method produces reliable results even in a small lake after rigorous data processing. After these procedures, about half of the CO2 and turbulent heat flux data were of good quality with relative random errors of 10 % and 26 % for heat and CO2 fluxes, respectively. When measuring GHG fluxes accurately from lakes, methods that integrate over time and space are a necessity. These will provide more detailed knowledge on the complex processes that contribute to the gas transfer, from large scale physical phenomena such as thermocline tilting to small scale such as near-surface turbulence. Since most of the world s lakes are small and in northern latitudes, our studies have wide implications even to the global level. Better understanding of the lake biogeochemistry will allow us to make more accurate estimates of GHG evasion from lakes in different regions as well as predictions of how the climate change will affect the lake-atmosphere GHG fluxes.Järvistä ilmakehään vapautuvien kasvihuonekaasujen (KHK) määrä riippuu valuma-alueen, järven ja ilmakehän välillä tapahtuvista prosesseista. Valuma-alueelta tuleva orgaaninen aines määrittää suurelta osin veden sameuden ja värin, jotka tuulen ja lämpövuon ohella vaikuttavat keskeisesti lämpötilan harppauskerroksen (termokliini) muodostumiseen. Lämpökerrostumisen vuoksi vain veden pintakerros on hyvin sekoittunutta, jolloin kasvihuonekaasuja pääsee kertymään alusveteen. Järven eliöstö hajottaa orgaanisen aineksen tuottaen hiilidioksidia (CO2), kun happea on saatavilla, ja jos alusvesi on hapetonta, lisäksi metaania (CH4). Näin eliöstö vaikuttaa myös vesipatsaan kemiaan. KHK:t vapautuvat lopulta ilmakehään ohuen pintakerroksen läpi. Järvet ovat tyypillisesti ylikyllästyneitä suhteessa ilmakehän CO2- ja CH4- osapaineeseen. Tällöin järvet ovat KHK:jen lähteitä. Vaikka maapallon pinta-alasta vain 2 % on järviä, nykyisten arvioiden mukaan järvistä vapautuu noin 10 % siitä hiilestä, jonka maaekosysteemit vuosittain sitovat. Kaasuvoita arvioitaessa kriittinen parametri on kaasunvaihtokerroin (k), joka on riippuvainen turbulenssista. Eddy kovarianssi -tekniikalla (EC) tehdyt suorat vuomittaukset mahdollistavat k:n tarkan arvioinnin. Järvillä EC:n käyttö on kuitenkin uutta, jonka vuoksi yleisesti hyväksyttyjä käytäntöjä ei ole vielä muodostunut eikä virhearvioita esitetty. Tämän työn tavoite oli arvioida nykyisiä globaaleja CO2-vuoarvioita järvistä ilmakehään vertailemalla eri k:n parametrisaatioita ja tuulen ja lämpövuon merkitystä pienten järvien kaasunvaihdossa. Tutkimme veden kirkkauden vaikutuksia vesipatsaan fysiikkaan ja vesi-ilmakehä-rajapinnan prosesseihin, mikä mahdollistaa tarkemmat tulevaisuuden ennusteet järvistä vapautuvista KHK:ista. Keräsimme aineistoa EC-menetelmällä ja yksi päämäärä oli kehittää EC-tekniikkaa järvillä. Veden ja ilmakehän välinen kaasunvaihto oli riippuvaista sekä tuulesta että lämpövuosta järven lämpökerrostumisen aikaan, mutta syystäyskierron aikana ainoastaan tuulesta. Tutkitulla Kuivajärvellä k:n keskiarvo oli 6.0 cm h-1. Tuuli aiheutti termokliinin kallistumista, jonka vuoksi pintaveden CO2-osapaineeseen muodostui alueellista vaihtelua. Kun tämä huomioitiin, mittauksista laskettu k:n keskiarvo laski 5.2 cm h-1:een. Tämäkin oli yli kaksinkertainen yleisesti käytössä olevan kaasunvaihtokerroinmallin antamaan arvoon verrattuna (2.2 cm h-1), jonka vuoksi globaalit arviot järvistä vapautuvista KHK:ista voivat olla aliarvioita. Lisäksi osoitimme, että CH4:n k oli suurempi kuin CO2:n tulos joka on havaittu eräissä muissakin tutkimuksissa, mutta jolle ei vielä ole löytynyt aukotonta selitystä. Veden kirkkaus oli keskeinen parametri, joka vaikutti järven lämpökerrostumiseen: kun pienen järven mallinnettiin muuttuvan kirkkaasta sameaksi, kerrostuneisuuskauden pituus lyheni ja vesipatsaan keskimääräinen lämpötila laski. Näillä tekijöillä oli merkittävää vaikutusta järven ja ilmakehän välisiin prosesseihin. Jatkossa tulisi tutkia, kuinka ilmastonmuutos vaikuttaa järvien sameuteen, kun sadanta ja siitä aiheutuva valunta ja ulkoinen kuormitus muuttuu. Tulostemme mukaan EC-menetelmä on luotettava pienillä järvillä, kun data käsitellään erittäin tarkoin laatukriteerein. Kuivajärvellä hyvälaatuiseksi luokiteltua CO2- ja turbulenttista lämpövuodataa jäi noin puolet, ja suhteelliset satunnaisvirheet olivat 10 % lämpövuolle ja 26 % CO2-vuolle. Kun halutaan mitata tarkasti järvien KHK-voita, pistemittausten sijasta tulisi käyttää menetelmiä, joissa mittaukset tehdään jatkuvasti ja suurelta pinta-alalta. Näin tuotettu tieto mahdollistaa kaasuvuohon vaikuttavien monimutkaisten prosessien tutkimisen, joita ovat niin suuret ilmiöt kuten termokliinin kallistuminen kuin pienen mittakaavan ilmiöt kuten pinnanläheinen turbulenssi. Valtaosa maailman järvistä sijaitsee pohjoisilla leveysasteilla ja sen vuoksi tuloksillamme on vaikutusta myös globaalilla tasolla. Järvien biogeokemian parempi ymmärtäminen tarkentaa KHK-vuoarvioita järvistä eri alueilla sekä järvien roolia ilmastonmuutoksessa

Software Contracting: A Process Model Approach

Experiences of making software development and purchase contracts between a user organization and several softwarevendorsareanalyzedoveradecade-longperiod. Threeinformationsystemshistoriesarepresented as case examples. The analysis is based on observations of the contract negotiations. Transaction cost frameworkisusedtoexplaintheformsofthejointorganizationalrelationsbetweentheparties. Theanalysis yields a descriptive model that depicts in a concise way how the relationships have evolved. The model identifies encounters between the vendors and the client which may change the contractual state between the parties. The passages between consecutive encounters are called episodes. By perceiving contractual systems development as a series of encounters and episodes, it is possible to identify the critical turning points of development work and to display the dynamics of contracting. The paper ends with a discussion of the findings and some implications for researchers and practitioners

Are benthic fluxes important for the availability of Si in the Gulf of Finland?

We estimated the efflux of dissolved silicon (DSi) from sediments in the Gulf of Finland and compared it to sedimentation fluxes, burial of Si and existing data on Si loading and stocks, reassessing the reliability of existing Si budgets. Benthic fluxes of DSi measured in situ and in vitro were several times higher than estimates from diffusion calculations. The spatial variability in the open Gulf of Finland was relatively small, while both very high and low fluxes were measured from coastal areas. Fluxes were highest in late summer and lowest in early spring. In our re-assessed budget we present a new lower estimate for Si burial in the sediments, ca. 6 Gmol a(-1) and show that more than half of the sedimentation flux of Si is released back into the water column. Changes in the efficiency of internal DSi recycling may thus affect the prevalence of siliceous phytoplankton within the ecosystem, and the diatom spring bloom may be regulated by the functioning of this internal recycling pump. We also show that the seasonal variation in benthic DSi fluxes and dissolved phosphate fluxes is similar, and that a tentative connection between hypoLxia and high DSi efflux exists. (C) 2017 Elsevier B.V. All rights reserved.Peer reviewe

Effects of Climate Change on CO2 Concentration and Efflux in a Humic Boreal Lake : A Modeling Study

Climate change may have notable impacts on carbon cycling in freshwater ecosystems, especially in the boreal zone. Higher atmospheric temperature and changes in annual discharge patterns and carbon loading from the catchment affect the thermal and biogeochemical conditions in a lake. We developed an extension of a one-dimensional process-based lake model MyLake for simulating carbon dioxide (CO2 ) dynamics of a boreal lake. We calibrated the model for Lake Kuivajarvi, a small humic boreal lake, for the years 2013-2014, using the extensive data available on carbon inflow and concentrations of water column CO2 and dissolved organic carbon. The lake is a constant source of CO2 to the atmosphere in the present climate. We studied the potential effects of climate change-induced warming on lake CO2 concentration and air-water flux using downscaled air temperature data from three recent-generation global climate models with two alternative representative concentration pathway forcing scenarios. Literature estimates were used for climate change impacts on the lake inflow. The scenario simulations showed a 20-35% increase in the CO2 flux from the lake to the atmosphere in the scenario period 2070-2099 compared to the control period 1980-2009. In addition, we estimated possible implications of different changes in terrestrial inorganic and organic carbon loadings to the lake. The scenarios with plausible increases of 10% and 20% in CO2 and dissolved organic carbon loadings, respectively, produced increases of 2.1-2.5% and 2.2-2.3% in the annual CO2 flux.Peer reviewe

High-frequency productivity estimates for a lake from free-water CO2 concentration measurements

Lakes are important actors in biogeochemical cycles and a powerful natural source of CO2. However, they are not yet fully integrated in carbon global budgets, and the carbon cycle in the water is still poorly understood. In freshwater ecosystems, productivity studies have usually been carried out with traditional methods (bottle incubations, C-14 technique), which are imprecise and have a poor temporal resolution. Consequently, our ability to quantify and predict the net ecosystem productivity (NEP) is limited: the estimates are prone to errors and the NEP cannot be parameterised from environmental variables. Here we expand the testing of a free-water method based on the direct measurement of the CO2 concentration in the water. The approach was first proposed in 2008, but was tested on a very short data set (3 days) under specific conditions (autumn turnover); despite showing promising results, this method has been neglected by the scientific community. We tested the method under different conditions (summer stratification, typical summer conditions for boreal dark-water lakes) and on a much longer data set (40 days), and quantitatively validated it comparing our data and productivity models. We were able to evaluate the NEP with a high temporal resolution (minutes) and found a very good agreement (R-2 >= 0.71) with the models. We also estimated the parameters of the productivity-irradiance (PI) curves that allow the calculation of the NEP from irradiance and water temperature. Overall, our work shows that the approach is suitable for productivity studies under a wider range of conditions, and is an important step towards developing this method so that it becomes more widely used.Peer reviewe

Towards a more comprehensive understanding of lacustrine greenhouse gas dynamics — two-year measurements of concentrations and fluxes of CO2, CH4 and N2O in a typical boreal lake surrounded by managed forests

Peer reviewe

Methane and carbon dioxide fluxes over a lake : comparison between eddy covariance, floating chambers and boundary layer method

Freshwaters bring a notable contribution to the global carbon budget by emitting both carbon dioxide (CO2) and methane (CH4) to the atmosphere. Global estimates of freshwater emissions traditionally use a wind-speed-based gas transfer velocity, k CC (introduced by Cole and Caraco, 1998), for calculating diffusive flux with the boundary layer method (BLM). We compared CH4 and CO2 fluxes from BLM with k CC and two other gas transfer velocities (k TE and k HE), which include the effects of water-side cooling to the gas transfer besides shear-induced turbulence, with simultaneous eddy covariance (EC) and floating chamber (FC) fluxes during a 16-day measurement campaign in September 2014 at Lake Kuivajarvi in Finland. The measurements included both lake stratification and water column mixing periods. Results show that BLM fluxes were mainly lower than EC, with the more recent model k TE giving the best fit with EC fluxes, whereas FC measurements resulted in higher fluxes than simultaneous EC measurements. We highly recommend using up-to-date gas transfer models, instead of kCC, for better flux estimates. BLM CO2 flux measurements had clear differences between daytime and night-time fluxes with all gas transfer models during both stratified and mixing periods, whereas EC measurements did not show a diurnal behaviour in CO2 flux. CH4 flux had higher values in daytime than night-time during lake mixing period according to EC measurements, with highest fluxes detected just before sunset. In addition, we found clear differences in daytime and night-time concentration difference between the air and surface water for both CH4 and CO2. This might lead to biased flux estimates, if only daytime values are used in BLM upscaling and flux measurements in general. FC measurements did not detect spatial variation in either CH4 or CO2 flux over Lake Kuivajarvi. EC measurements, on the other hand, did not show any spatial variation in CH4 fluxes but did show a clear difference between CO2 fluxes from shallower and deeper areas. We highlight that while all flux measurement methods have their pros and cons, it is important to carefully think about the chosen method and measurement interval, as well as their effects on the resulting flux.Peer reviewe

Extracorporeal photopheresis in the treatment of acute graft-versus-host disease : a single-center experience

BACKGROUND: Steroid-refractory acute graft-versushost disease (aGVHD) is a serious complication after hematopoietic stem cell transplantation. The long-term outcome of the patients is poor. Various immunosuppressive agents have been proposed as the second-line therapy but none of them has turned out more effective than the others. Extracorporeal photopheresis (ECP) is a treatment option that does not predispose the patients to severe side effects of the immunosuppressive drugs. STUDY DESIGN AND METHODS: We analyzed the treatment results of ECP in 52 patients with steroidrefractory or steroid-dependent aGVHD. Eighty-one percent of the patients suffered from a severe, Grade III or IV, aGVHD. ECP was started alone as the second-line treatment in 23 patients and in combination with an immunosuppressive drug in 18 patients. Eleven patients received ECP as the third-line or later treatment. RESULTS: A total of 62% of the patients responded, with 48% achieving complete response. In the patients with complete or partial response, the probabilities of survival at 4 years were 54 and 17%, respectively. The outcome of nonresponders was poor. The 1-year overall survivals of the patients with ECP as the second-line treatment either alone or in combination with an immunosuppressive drug or as the third-line treatment were 51, 28, and 18%, respectively. In multivariate analysis, starting ECP no later than 10 days after the start of the first-line treatment correlated with a good response and a consequent survival benefit. CONCLUSION: Extracorporeal photopheresis is an effective and well-tolerated treatment that should be considered as a second-line treatment for aGVHD.Peer reviewe