The Influence of Mechanical Circulation on Water Column Stability and Dissolved Oxygen in Stratified Lakes

Surface circulators have been used in wastewater and industrial lagoons for many years, but only recently have they been designed for lakes and reservoirs as a water quality management tool. Their relatively low capital investment and operational costs make them an attractive chemical free option for ameliorating the symptoms of eutrophication. Little research has been conducted on their effectiveness in impacting water quality. Today many lake managers are waiting for independent research on surface circulators\u27 performance before installing such systems. The Occoquan Reservoir was the primary site for a study conducted to examine the influence of surface circulation on water quality. Eight surface circulators were installed in the reservoir in 2006 in an effort to lower iron and manganese by increasing dissolved oxygen in the lower waters. Oxygen and temperature profiles were recorded at three main sampling sites from April through October 2007. These data were compared with historical data collected by the Occoquan Watershed Monitoring Laboratory (OWML) to determine the influence of circulator operation. Near field flow studies were conducted around one circulator using an acoustic doppler velocimeter (ADV). It was found that the circulators had significantly less influence on the temperature and dissolved oxygen of Occoquan Reservoir. This appeared to be contributed by the low circulation flow rates that were measured. A modeling effort was also conducted to simulate measured temperature and dissolved oxygen profiles through 2007. Since CE-QUAL-W2 does not explicitly contain a module to directly simulate surface circulation, the pump module was modified to transfer water from a discrete depth in the hypolimnion to the surface. After a satisfactory agreement between measured and simulated temperature and dissolved oxygen profiles was obtained, the unknown zero flow condition of the reservoir was studied. Next, a series of hypothetical lakes were simulated to explore the influence of various lake sizes, circulation flow rates, and intake depths on the temperature and dissolved oxygen distribution. It was found that the vertical temperature distribution was relatively easy to affect, and it responded to the physical mixing from the surface circulators in a conservative manner. The vertical dissolved oxygen distribution was harder to influence since it was controlled by many processes involving oxygen supply and demand in the water column and the sediments. A new approach for evaluating the circulator performance was developed based on the reduction in sediment area subjected to anoxic overlaying water. This reduction in anoxic sediment area is considered proportional to the reduction in iron and manganese to the lake, and would therefore represent a benefit to the water quality

Stovner - problemområde eller lutter idyll? : om forholdet mellom statistikk og erfaring

Stovner var og til dels er et av Norges mest utskjelte boområder og assosieres med «problem». Bydelen har i de senere år fått mange nye beboergrupper, og kan statistisk sett betegnes som en underprivilegert bydel, preget av dårlige levekår i betydningen lav inntekt og utdannelse, høy arbeidsledighet og høy andel sosialhjelpsmottakere. Vårt anliggende er å undersøke hva stedet Stovner betyr for menneskene som bor der og hvorvidt, og i tilfelle hvordan, de opplever det som et sted som gir dem muligheter, eller som et sted som begrenser deres sjanser til et godt liv. Dette diskuterer vi gjennom forskjellige beboergruppers fortellinger om «sitt Stovner» og gjennom den offentlige historien om bydele

Children’s Agency in Translocal Roma Families

Peer reviewe

Social Control in Transnational Families: Somali Women and Dignity in Johannesburg

Transnational mobility often separates families and distances individuals from the kinship and social structures by which they organized their lives prior to migration. Myriad forms of insecurity have been the impetus for Somali movement into the diaspora, with people fleeing the realities of conflict that have marked Somalia for decades while physically dividing families as individuals settle in different countries around the world. Mobility has altered the dynamics of households, families, and communities post-migration, reshaping social constructions as individuals move on without the familial support that sustained them in Somalia. While outcomes of these hardships are variable and often uneven in different settlement spaces, migration can offer new opportunities for people to pursue avenues from which they were previously excluded, such as by assuming roles and responsibilities their relatives once filled. These changes precipitate shifting identities and are challenging for women who find themselves self-reliant in the diaspora, particularly in the absence of (supportive) husbands and close kin.Drawing on ethnographic research in Johannesburg’s Somali community, this chapter explores the assumption that migration provides an opening for women to challenge subordinating gender norms. Settlement often grants women greater freedom to make choices in their lives, such as in employment and personal relationships, and yet they remain constrained by networks that limit their autonomy. Even with transnational migration and protracted separation, women are family representatives who must uphold cultural notions of respectability despite realities that position them as guardians and family providers. Women remain under the watchful eye of their extended families through expansive networks and the ease of modern communication, which facilitate a new form of social control as women’s behavior is carefully monitored and reported to relatives afar. These actualities raise questions about the degree to which transnational movement is a liberating force for women or rather a reconfiguration of social control. I argue that despite women’s changing position in their households and families, they remain limited by social control within their extended families and communities

Ensuring the right to education for Roma children : an Anglo-Swedish perspective

Access to public education systems has tended to be below normative levels where Roma children are concerned. Various long-standing social, cultural, and institutional factors lie behind the lower levels of engagement and achievement of Roma children in education, relative to many others, which is reflective of the general lack of integration of their families in mainstream society. The risks to Roma children’s educational interests are well recognized internationally, particularly at the European level. They have prompted a range of policy initiatives and legal instruments to protect rights and promote equality and inclusion, on top of the framework of international human rights and minority protections. Nevertheless, states’ autonomy in tailoring educational arrangements to their budgets and national policy agendas has contributed to considerable international variation in specific provision for Roma children. As this article discusses, even between two socially liberal countries, the UK and Sweden, with their well-advanced welfare states and public systems of social support, there is a divergence in protection, one which underlines the need for a more consistent and positive approach to upholding the education rights and interests of children in this most marginalized and often discriminated against minority group

Forlatte barn, ankerbarn, betrodde barn ...

Rapporten er utarbeidet for NOVA av Ada Engebrigtsen. Rapporten handler om enslige, mindreårige asylsøkere i Norge med vekt på deres familiebånd og bakgrunn og hvordan det offentlige tilrettelegger for at disse barna skal kunne opprettholde denne tilknytningen og knytte nye bånd i Norge. Situasjonen i Nederland vil bli brukt som et komparativt eksempel. Studien er basert på intervju med 25 personer som arbeider med enslige, mindreårige asylsøkere på forskjellige nivå i privat og offentlig virksomhet i Norge og i Nederland. Rapporten stiller en rekke kritiske spørsmål til asylpolitikk og praksis overfor denne gruppa i Norge. Ada Engebrigtsen uttaler om rapporten: - Asylsøkerbarn blir ikke tatt nok hensyn til i søknadsbehandlingen hos UDI. De får ikke komme til orde og blir usynliggjort i sine egne søknader, med svekket rettssikkerhet som resultat

Forlatte barn, ankerbarn, betrodde barn ...

Rapporten er utarbeidet for NOVA av Ada Engebrigtsen. Rapporten handler om enslige, mindreårige asylsøkere i Norge med vekt på deres familiebånd og bakgrunn og hvordan det offentlige tilrettelegger for at disse barna skal kunne opprettholde denne tilknytningen og knytte nye bånd i Norge. Situasjonen i Nederland vil bli brukt som et komparativt eksempel. Studien er basert på intervju med 25 personer som arbeider med enslige, mindreårige asylsøkere på forskjellige nivå i privat og offentlig virksomhet i Norge og i Nederland. Rapporten stiller en rekke kritiske spørsmål til asylpolitikk og praksis overfor denne gruppa i Norge. Ada Engebrigtsen uttaler om rapporten: - Asylsøkerbarn blir ikke tatt nok hensyn til i søknadsbehandlingen hos UDI. De får ikke komme til orde og blir usynliggjort i sine egne søknader, med svekket rettssikkerhet som resultat