bluuebunny/crossref_metadata_2025 huggingface dataset:
Tunneled internal jugular catheters in adult patients: comparison of outcomes in hemodialysis versus infusion catheters
Authors: Peynircioglu B. , Ozkan F. , Canyigit M. , Cil B. E. , Balkanci F.
Published: July 2007

Background: Tunneled central venous catheters placed by interventional radiologists are now widely used for hemodialysis and infusion therapies throughout the world. However, complications such as infections and malfunctions still remain a major concern in oncology and hemodialysis patients.

Purpose: To evaluate the long-term follow-up results of tunneled central venous catheters in an adult population in terms of infectious complications and malfunction rates in dialysis and oncology patients.

Material and Methods: We retrospectively reviewed the hospital charts and our electronic database for 434 tunneled internal jugular catheters in 335 consecutive patients between December 2002 and March 2006. Mean patient age was 57 years (range 23–86 years) in the hemodialysis group and 45 years (range 18–83 years) in the infusion group. A total of 224 hemodialysis catheters were placed in 168 patients (68 females, 100 males) and 210 infusion catheters in 167 patients (48 females, 119 males).

Results: Technical success rate was 100%. Mean duration of catheter use was 86 days (1–652 days) and 60 days (2–686 days) for hemodialysis and infusion catheters, respectively. A total of 107 hemodialysis (47%) and 95 infusion catheters (45%) were electively removed due to completion of therapy and resolution of need for dialysis. Revisions were performed 0.22 and 0.11 per 100 catheters days in the hemodialysis and infusion groups, respectively. Our total infection rate was 0.10 episodes per 100 catheter days, and the rate of infections necessitating catheter removal was 0.05 episodes per 100 catheter days in the hemodialysis group, which is lower than that reported in other big series. However, in the infusion group, the rate of infections necessitating catheter removal was 0.28 episodes per 100 catheter days.

Conclusion: Long-term central venous accesses using tunneled internal jugular catheters appeared to be safe and effective for both hemodialysis and long-term infusion therapies, with relatively higher infection rates in oncologic patients.
Tanzania: AIDS care – learning from experience
Authors: Nnko Soori , Chiduo Betty , Wilson Flora , Msuya Wences , Mwaluko Gabriel
Published: July 2007

Given heterosexual transmission and mother to child transmission, AIDS often strikes more than once within the same family. This is debilitating but can also be a learning experience for carers whose knowledge might then be a resource for the community. This article describes a pilot study into the experience of 21 main care providers in families with chronically ill people suffering mainly from AIDS, each one having cared for and supported more than one patient. During the study 46 out of 51 patients who were cared by these 21 care providers had already died. Respondents provided information on care and support given to the first patient and how much they were prepared and experienced at giving quality care to the next patient. This study provides data from in‐depth interviews conducted between April and June 1999 in a suburb of Mwanza, a city in northwestern Tanzania.
Community fencing in open rangelands: self‐empowerment in Eastern Namibia
Authors: Twyman Chasca , Dougill Andrew , Sporton Deborah , Thomas David
Published: July 2007

This article examines the cross‐cutting debates of empowerment, vulnerability, sustainability and livelihoods within the local and global contexts relevant to the people of Okonyoka, a settlement of less than 150 people situated in the heart of Eastern Namibia's southern communal lands. Here, people are adapting their livelihoods flexibly in response to both environmental natural resource variability and to changes in social institutions and land use policies. Drought‐coping strategies, privatisation of the range through fencing and changes to social networks, all have both positive and negative impacts on people's everyday lives. Okonyoka is the first settlement to erect a community fence in Eastern Namibia's southern communal area, but surrounding settlements are impressed with the positive environmental and societal results and are planning to follow suit. Such fences can, however, inhibit neighbouring people's livihoods, particularly the poor or socially excluded, and can change long‐standing regional drought‐coping strategies. Though the policy context is dynamic and changing, such moves have the potential to radically change the landscape of communal areas.
Interview with Brahim Bedileh, commander, 2nd military region (tifariti), POLISARIO front
Authors: Bhatia Michael
Published: July 2007

The following transcript was conducted through an interpreter on 25 April 2001, and therefore is an approximation and not fully representative of Commander Bedileh's statements:

BB:We are currently in a stand‐by position, still waiting. Nobody wants to lose time in waiting to resolve our problem of liberation. 26 years of fighting for our existing rights of self‐determination, our case is one of legal consensus that we see all over the world.
Debate intensifies over adjustment & press freedom in Mozambique
Authors: Hanlon Joseph
Published: July 2007

A criminal slander action brought by the son of the president of Mozambique against a journalist and the children of an assassinated editor have brought to the surface debates on race, development strategy and the role of the press. These are taking place in the shadow of Zimbabwe and in the context of international donors wanting to give more money to Mozambique because it is seen as a success story of World Bank and IMF policies.
Zanzibar's turbulent transition
Authors: Cameron Greg
Published: July 2007

On 29 October 2000, 10 million voters in 231 constituencies cast their votes for 13 political parties throughout Tanzania. The election on the Tanzanian mainland was predictably won by the ruling CCM (Party of the Revolution) against a divided and weak opposition. In Zanzibar, on the other hand, the CCM faced a fierce challenge from the CUF (Civic United Front) as approximately 450,000 people voted in 50 constituencies for the Union and Zanzibar Presidents, and candidates for the Union and Zanzibar Legislatures. The elections on Zanzibar were grossly mismanaged and deepened the growing political crisis in the United Republic of Tanzania. And indeed, on 27 January 2001, throughout the major cities of Tanzania, there were mass protests against the electoral coup on Zanzibar. The police killed between 30 and 70 people and wounded upwards of 600 people. Thousands fled to the mainland and more than 2,000 Zanzibaris, mainly Pembans, fled to Kenya as refugees (Human Rights Watch, April 2002).
Book notes
Authors: Love Roy
Published: July 2007

Van de Walle, Nicolas,
African Economies and the Politics of Permanent Crisis, 1979–1999,Cambridge University Press 2001.

Zack‐Williams, T, D Frost & A Thomson(eds.), Africa in Crisis: New Challenges and Possibilities,Pluto Press, London 2002

Cumming, G,
Aid to Africa: French and British Policies from the Cold War to the New Millenium,Ashgate 2001.

Saugestad, Sidsel,
The Inconvenient Indigenous: Remote Area Development in Botswana, Donor Assistance, and the First People of the Kalahari,Nordic Afrika Institute, Uppsala, 2001.

Lester, A, E Nel, T Binns,
South Africa, Past, Present and Future: Gold at the End of the Rainbow?,Prentice Hall 2000.

Nagel, S S(ed.), Handbook of Global Political Policy,Marcel Dekker, 2000.
The people's mood: the voice of a Guerilla Poet
Authors: Mzamane Mbulelo
Published: July 2007

The article on Chimedza's work by is a new departure for us — into the field of poetry. Its significance is as a powerful expression of the hopes and aspirations of the young guerillas who fought and won the war against the settlers. Through the poetry of one of them, Chimedza, ably interpreted by the author, we see the brutality of colonialism and the resistance it engendered through the eyes of one militant youth. The poems are divided into three categories: the economy, the oppressive conditions and the war effort. Above all though, the poems articulate the expectations of the people, which the future govenment of Zimbabwe will rapidly have to meet. This is the key message which Mzamane draws from his study. The article finishes by speculating on the future literary trends in Zimbabwe and examines the role of writers as critics of African governments.
What is happening to the Kenyan peasantry?
Authors: Ng'ang'a D.
                      Mukaru
Published: July 2007

The peasant question in Kenya has attracted a lot of debate. This essay takes up the issue of what is happening to the Kenyan peasantry by first and foremost questioning some false assumptions and concepts involved in the debate. For example, are peasants property owners? If so, is this property mainly in land? What happens when peasants either accumulate or become impoverished: do they cease to be peasants as Atieno‐Odhiambo once suggested?
Class struggles in Mali
Authors: François Pierre
Published: July 2007

Over the last few years, Mali has undergone a structural and conjunctural crisis. Especially since 1973, the year when the Western media ‘discovered’ the Sahel drought, its economic foundations have been thrown into disarray. Even more recently, a crisis of government has been precipitated as reflected in numerous attempted coups d'etats. The convergence of these processes has left Mali in a state of shock out of which serious social contradictions will emerge over the next few years. François attempts to analyse recent events in terms of Mali's historical past and the principal structural problems within the econmy and society emergent during the colonial period and persisting following independence. He goes on to examine some of the forms which resistance and conflict have taken, and explores possible strategies for popular participation.
The politics of famine in Ethiopia
Authors: Lemma Hailu
Published: July 2007

In the last few months the media has presented us with the stark human tragedy and the prospect of even more starvation and dehumanising conditions inflicted on the peoples of Ethiopia. There are several factors, both external and internal, that have contributed to such human catastrophe. The West has often used food‐aid as a political weapon. It is clear that relief aid has been withheld from starving children in order to weaken governments opposed to Western interests. On similar grounds some UN agencies who have tried to help Third World countries have seen their funds withdrawn. The Western media and charity organisations are not going to escape blame, mostly because of their failure to publicise the famine property; the scale and urgency of the tragedy were known to them much earlier. The approach of the Soviet Union and the Left is equally deplorable; they have done little or nothing. To sit aside and blame the West while millions are starving to death lacks any ‘socialist justification’. The Ethiopian government must bear heavy responsibility, although it has been anxious to cover up its faults in the wake of the public outcry, framing the famine as a natural disaster. The political and economic reasons are conveniently ignored. This is all very well to raise relief aid to relieve starving victims; for the starving nothing is too late. The high defence spending and the obsession to end the civil unrest by military means has crippled the agricultural sector. The extent of the crisis and the human tragedy is thus not entirely due to natural causes; it is mostly man‐made and preventable.
Morocco and the Western Sahara
Authors: Seddon David
Published: July 2007

This article offers a detailed summary of the stages of the war that has been waged since the end of Spanish colonial rule in Western Sahara. It documents the forms of struggle used by the Polisario Front in its efforts to end the enforced division of Western Sahara between Morocco and Mauretania in 1976, and, after 1979, the efforts of Morocco to incorporate the territory. It also offers a summary of the international political dimensions of the struggle — the diplomatic and military aid Morocco receives from the West, especially the USA, and the support of some OAU members and in the UN for the rights of self‐determination of the Saharan people. It concludes with an assessment of the impact of the war on Moroccan politics, society and economy.
BAT and the penetration of capital into Oyo state
Authors: Babalola Ademola
Published: July 2007

This study concerns the movement of international capital by British American Tobacco (BAT) into the Oyo North division of Oyo State, Nigeria, and investigates the control by the company over the farmers; that this control stops short of full proletarianisation nor does Ulead to a clear pattern of stratification along class lines.
Somalia in perspective: when the saints come marching in
Authors: Weil Robert
Published: July 2007

When I give food to the poor, they call me a saint. When I ask why the poor have no food, they call me a communist(Brazilian Archbishop Dom Helder Camara)
Human rights abuses in Sudan
Authors: Nhial A
                      Agaw Jok , Kafi Nur
                      Tawir , Seisi Eltigani
Published: July 2007

Human rights abuses in the Sudan are all pervasive and in 1992-93 there was an international outcry from the UN Security Council, the US and the European Community condemning the Sudan government. This Briefing examines abuses in the South, Nuba Mountains and Darfur. What follows is just a sample of the human rights abuses in the Sudan. Because of the security clampdown and the danger to anyone collecting data, the authors have relied largely on secondary sources – human rights organisations, NGOs and international agencies.
Back to the future? A critical review of ‘adjustment in Africa: reforms, results and the road ahead’
Authors: Sepehri Ardeshir
Published: July 2007

The World Bank's report, Adjustment in Africa, Reforms, Results, and the Road Ahead (hereafter A in A), provides the most comprehensive data so far on policy changes and results for adjusting Sub‐Sahara African countries. The report selectively uses data to prove that adjustment is working, payoffs to policy reforms are large, and the region is on the road to a sustained, poverty‐reducing growth path. A re‐evaluation of the report's own data suggests that there is sufficient evidence to be concerned about the sustainablity of adjustment results. After many years of experience with adjustment policies, growth rates are still low, as are saving and investment rates — even for the strong adjusters. Modest GDP, agricultural and industrial growth rates, combined with a deterioration in social services all cast doubt on the region's prospect for checking the growth of poverty before the next two or three decades.
Development and diaspora: separate concerns?
Authors: Zack‐Williams Alfred
Published: July 2007

The article considers recent work on the nature of the black diaspora in the West and its relationship with Africa and African development. It condemns the disciplinary gulf between development studies, which has almost completely ignored questions of race and cultural identity, on the one hand, and diaspora studies which tend to focus on cultural and racial links with Africa to the exclusion of questions of political economy. The review is critical of perspectives which ignore the heterogeneity and variety of African cultures and experience, whether for purposes of creating a caricatured colonial subject or for asserting an undifferentiated unity between Africans on the continent and in the diaspora. It argues for an understanding of both the uniqueness and the commonality of African experiences on both sides of the Atlantic.

The Black Atlantic: Modernity and Double Consciousness by P. Gilroy, Cambridge, MA: Harvard University Press, 1993; In My Father's House by K. A. Appiah, New York, 1992; Black Feminist Thought: Knowledge, Consciousness, and The Politics of Empowerment by P. Hill Collins, Unwin Hyman, 1990.
Peacekeeping: the African dimension
Authors: Cleaver Gerry , May Roy
Published: July 2007

Following the end of the cold war there developed a general perception that the United Nations would now be able to adopt a more enhanced role as the world's peacekeeper and peacemaker, especially if it enjoyed the support of the US. This view appeared to be vindicated following the successful US led UN operation to liberate Kuwait from Saddam Hussein in 1991. However, since then the reluctance of the West to become involved in Africa's conflicts unless it is for their own ends, points to establishing an African peacekeeping structure. Yet as this article demonstrates, the political and military structures are not yet in place, nor is there any likelihood that there is any organisation to fill the post‐cold war security vacuum.
The plight of the Agro‐pastoral society of Somalia
Authors: Mukhtar Mohamed
                      Haji
Published: July 2007

Despite advances in modern communication and the proliferation of information, there remain areas of the world about which little is known. One such place is Somalia. The informed public is aware of a political ‘meltdown’ and consequent chaos there, but few comprehend the causes of this tragic crisis. Unless and until there is greater understanding of the basic issues involved, Somalia will continue to suffer mayhem and chronic disorder. This article assesses some of the factors involved in the current civil war in Somalia, especially as they pertain to the inter riverine region of the south. Particular emphasis is placed on the Dighil/Mirifle clan in that region.

In contrast to the single cause analysis that attributes all to Siad Barré's dictatorship, which is adopted by nearly every Somali scholar and politician, the article investigates the social causes of the worst civil war in the modern history of this country. The single cause analysis is inadequate because it is not so much scientific as ideological, and represents the desire of nomadic groups to impose cultural and political hegemony on the settled agro‐pastoralist groups in and around the inter‐riverine region in the south. The basic tenet of this hegemonic ambition is an invented homogeneity, which presents Somalia as one of the few culturally homogeneous countries in Africa, if not the world. The Somali people are said to have a single language and to share a mono‐culture. In fact, Somalia has always been divided into southern agro‐pastoral clans and northern nomadic clans which have distinctively different cultural, linguistic, and social structures. The monoculture about which most students of Somalia speak is extrapolated mainly from the study of the northern part of the country, where most of the research into Somali culture was undertaken. The assumptions and extrapolations of these northern‐based studies were later applied to other parts of the country without any scientific basis. The myth of Somali homogeneity played a major role in the rise of nomadic clans to political predominance, and the appropriation of resources from the less warlike and intensely religious agro‐pastoral groups in and around the inter‐riverine region. A major factor in the Somali conflict is the struggle among clans for control of limited and increasingly scarce resources, especially land and water. More specifically, it is a violent competition between the Darood and Hawiye clan families for political and economic dominance of the inter‐riverine region.
The 1996 Zambian elections: still awaiting democratic consolidation
Authors: Baylies Carolyn , Szeftel Morris
Published: July 2007

On 18 November 1996 presidential and parliamentary elections were held for the second time under Zambia's Third Republic. The first elections, in October 1991, ended the unbroken grip on power enjoyed by the United National Independence Party (UNIP) since 1964 and returned the country to a multi‐party political system after 18 years as a one‐party state. UNIP was heavily defeated by the MMD (Movement for Multiparty Democracy) and Kenneth Kaunda, the country's president since 1964, was replaced by Frederick Chiluba. The peaceful nature of the changeover in 1991 was applauded locally and internationally. There was a sense of optimism about the country's democratic prospects. Zambia was widely held up as a model of successful democratic transition and aid flowed in, partly in support of the democratic experiment and partly because of the new regime's commitment to economic liberalisation and structural adjustment. In some cases donor support was specifically earmarked for the promotion of good government and the encouragement of civic education (Endnote 1).
International commercial rivalries & the zai'rian copper nationalisation of 1967
Authors: Gibbs David
Published: July 2007

Research on the international relations of the African continent has generally eschewed the phenomenon of rivalry among the advanced capitalist powers for commercial and political influence south of the Sahara. Most studies of Africa's international relations, especially from a critical perspective, have tended to emphasize the unityof the northern, capitalist powers in opposing challenges from third world countries. During the 1970s, research emphasized the efforts of multinational corporations and their home governments to prevent or undermine efforts at economic nationalism in third world countries. While such studies did recognize the potential for somewhat varied responses to rationalistic ‘threats’, there was a widespread assumption that the rich nations would exhibit a significant degree of unity in preserving international property rights and the free flow of capital. More recently, critical studies have emphasized the salience of the international financial community and the International Monetary Fund in reestablishing political and economic hegemony over peripheral areas, including Africa (Mohan & Zack‐Williams, 1995).

Such approaches tend to overlook the phenomenon of conflict and competition among these powers. This article will examine the historical basis of international rivalries in Zaïre, focusing on the rise of General Mobutu's regime, primarily during the late 1960s. During this period, the United States was seeking to expand its commercial and political influence in Zaïre, generally at the expense of established European interests. The principal protagonist of the US was the former colonial power, Belgium. In essence, it will be argued, inter‐capitalist rivalries in Zaïre were an inevitable outgrowth of decolonization. The European powers had always used colonialism as a method to maintain exclusive or quasi‐exclusive trading and investment opportunities for home country interests and to exclude potential interlopers ‐ such as the United States. During the 1960s, the US viewed the circumstances of decolonization as an opportunity for political and commercial expansion, sometimes at the expense of European interests. European‐US conflicts, some of which continue to the present day, were the result. Historical conflicts such as these are highly relevant to understanding present‐day international relations in Central Africa when once again, rivalries among the western powers ‐ this time between the US and France ‐ are apparent.
Mirages of pastoralist futures: a review of aid donor policy in Sahelian pastoral zones
Authors: Oxby Clare
Published: July 2007

Based on donor presentations at the United Nations Sahelian Office (UNSO) Technical Consultations on Pastoral Development in Africa (Endnote 1), this contribution explores first the extent to which pastoralists and the pastoral zones are targeted in donor policy and second the type of future society that the aid policies point towards, or imply, for these people and these regions. The policies are found to divide into those that effectively bypass pastoral zones and fail to target pastoralists, those that consider the pastoral zones and their inhabitants as complementary to other zones and other populations, and those that target squarely these zones and their inhabitants. Taking the last group of policies, three different approaches are distinguished: that which focuses on livestock and animal production; that which focuses on people and herders’ organisations; and that which focuses on natural resources and desertification. These policies are reviewed in turn, along with their contrasting and often unrealistic implications as to the type of future society involved.

In the end, most of these visions of the future are dismissed as hypothetical constructs — as mirages — in that they tend to be formulated by outsiders and lack a consensus of support from within the pastoralist communities. In the current political climate which favours democracy and decentralisation it is hoped that the pastoralists themselves will be given a voice and an institutional channel in proportion to their numbers, so that they may formulate and express their own aspirations. Certain very fundamental issues have yet to be resolved through the political process, in particular the relative support for two opposing lifestyles and land uses in semi‐arid areas: one based on nomadic livestock‐keeping of drought‐resistant livestock species, and the other on a variety of sedentary activities based in farms and settlements. Finally, some examples are suggested of ways in which donors might be called upon to assist, rather than to initiate, efforts towards the improved political representation of pastoralists.
The Maghreb experience: a challenge to the rational myths of economics
Authors: Zaoual Hassan
Published: July 2007

Colonial domination gave way to ‘development through regulation’ which received support from the Third World elites. Historically, the elites of the South have usually imported everything, including the explanation for the problems of their own societies: ‘from the discourse (keys in head), to the factory (keys in hand)’. In economic development circles, the Third World elites play the role of sterile classes without the capacity to create ‘development’. On the world economic scene, the development industry has concentrated conceptual ability and innovatory capacity in the countries transmitting development, while the sterile classes head what are essentially rentiereconomies (Philippe Hugon, 1994). Development, despite its impressive array of macro models, all too often turns out to be merely a source of profit for the closed club of the great economic powers of the world. But this relationship cannot be maintained without flourishing markets for primary commodities (for example, oil), external assistance, geopolitical rents, demographic pressures that can be kept within the redistribution capacity of rents, industrial sub‐contracting by transnationals (when this is feasible), and so on. If one or more of these conditions change, inevitably there is instability, if not explosions of all kinds. In fact, the results have been disastrous everywhere, except for the Asian development experiences whose successes have however been vitiated by the recent stock exchange crashes. This has challenged both the usual theory and practice of thinking and acting as far as North/South relationships are concerned — as evinced by recent international events.

The changes that are taking place, however, cannot be understood with the conceptual paradigms of yesterday. This ‘interpretation powerlessness’ can today be seen in the various geographical regions of the world. Examples are the Arab world, that ‘decadent old merchant’, and sub‐Saharan Africa, which is being massacred by ‘ethnic’ conflicts and endless external interventions. For these areas, it is all too clear that development is above all a source of profit for the capitalist economies of the North.
Der Einfluß von kapillarinaktiven Beimengungen auf die Kristallisation von Metallschmelzen
Authors: Kuševa‐Markova N. , Bliznakov G. , Triffonova E.
Published: July 2007

Nach einer Übersicht über den Stand der Kenntnisse über die Modifizierung des Gefüges von Gußmetallen werden eigene Ergebnisse über die Untersuchung des Einflusses von kapillarinaktiven Zusätzen (Mg, Zn) auf das Gefüge von Pb‐Metall mitgeteilt und diskutiert. Es wird die schon früher mitgeteilte Auffassung der Autoren über die Bildung einer hemmenden Adsorptionsschicht an der Phasengrenze und die damit verbundene erhöhte Keimbildungsgeschwindigkeit bestätigt.
Stability of faceted growth forms from melts and in the presence of impurities
Authors: Chernov A. A.
Published: July 2007

Transition from regular polyhedron to skeleton shape for crystals growing from melts is considered. This transition is due to the lower undercooling in central parts of facets as compared with vertexes. It is the growth rate anisotropy which withstands to that undercooling inhomogeneity.

For very strong anisotropy the stability criterion is determined as the crystal size above which the undercooling in the centers of facets approaches zero.

For arbitrary anisotropy the stability criterion presents the relationship between crystal size and small distortion of facets.
Haidingerite (II). From Valence Summation to Hydrogen Bonding
Authors: Donnay J. D. H. , Donnay Gabrielle
Published: July 2007

The haidingerite formula must be written CaAsO3(OH) · H2O. The calcium coordination number, reported as 6, is shown to be 7 by valence summation. Chains of hydrogen‐bonded arsenate groups are confirmed. The two protons of the water molecule form hydrogen bonds to neighboring chains.
Ein Beitrag zur Erzeugung dünner orientierter Antimonfilme auf Einkristallsubstraten durch Hochvakuumkondensation
Authors: Mietz I. , Sprenger H.
Published: July 2007

In Abhängigkeit von der Substrattemperatur, der aufgedampften Schichtdicke und der Aufdampfrate wurde die Kondensation von Antimon auf NaBr‐Epitaxieschichten und auf Muskovit bei 10−5 Torr untersucht. Auch bei Substrattemperaturen oberhalb 1/3 Ts (Ts Schmelzpunkt) erfolgt bis zu einer kritischen Substrattemperatur (für Muskovit > 150°C, für NaBr‐Epitaxieschicht < 150°C) die Kondensation über die amorphe Phase. Oberhalb dieser Substrattemperatur bildet sich die kristalline Phase direkt aus der Dampfphase.

Bei einer bestimmten Schichtdicke kristallisiert die amorphe Phase. Die dabei auftretende Orientierung ist schichtdickenabhängig.
Crystallization of potassium acid phtalate
Authors: Šolc Z. , Kvapil Jos. , Vlček Jos.
Published: July 2007

This paper gives some fundamental data which are necessary for the growing of crystals of potassium acid phtalate. The solubility of that phtalate, the values of critical supersaturation of its solutions in water and in solutions containing 0–15% of glycerine and the values of crystal growth rates of the {111} and {001} faces are given. The growth rates R were measured in 10% glycerine solutions of various values of supersaturation (Δa) and of various values of the solution flow rate (v). The saturation temperature was 33 – 35°C. The dependence of R(111) on the supersaturation Δα and the flow rate v was expressed by the equation

The values of coefficients a*, b*1, b*2 were calculated by means of the least squares method. The coefficient b*1 corresponds to the formal kinetic order, its value was 1.79 for 0.3 ≦ Δa ≦ 1.25 and 6 ≦ v ≦ 22. – The values of growth rates of basal faces (001) may be obtained when using the value of ratio q = R(111)/R(001). The measurements of growth rates were made in crystallizer of the circulation type and in solutions containing 10% of glycerine to prevent the defect or parasitic growth and the twinning of crystals.
Eine Methode zur röntgenographischen Orientierungsbestimmung dünner einkristalliner Schichten auf einem Substrat, angewandt bei der Untersuchung von Tantal auf Saphir
Authors: Meyer S. , Schneider H. G.
Published: July 2007

Durch Schrägbestrahlung und Verwendung charakteristischer Strahlung kann man eine einkristalline dünne Schicht einer röntgenographischen Orientierungsbestimmung auf einem Substrat zugänglich machen. Bei definierter Bewegung von Schicht und Zählrohr sind die entsprechenden Lauereflexe genau bestimmbar und ermöglichen eine vollständige Orientierungsangabe. Die Methode und Besonderheiten der Auswertung werden beschrieben. Diese Methode wurde für Orientierungsbestimmungen an einkristallinen Tantalschichten auf Saphir angewendet.
Preparation and study of extremely pure naf single crystals
Authors: Voszka R. , Raksányi K. , Földvári I.
Published: July 2007

The authors employed various physical and chemical methods for the purification of NaF. The efficiency of these methods was controlled by absorption measurements and chemical analysis. From purified material a single crystal was grown in every case, the absorption of which was measured by a vacuum ultraviolet spectrophotometer in the far UV wavelength range. The absorption at 142 nm was found to be indicative of the presence of several transition and heavy metal ions. The effect of doping with several alkaline and alkaline earth ions and furthermore with Cl− and OH− ions on these spectra is discussed. It is shown that certain chemical methods used for purification introduce Cl− ions into the material which are detectable by UV‐spectrophotometry.
Strahlende Rekombination aus Nichtgleichgewichtszuständen in katodenstrahlangeregtem GaN
Authors: Schwabe R. , Zehe A. , Hänsel T.
Published: July 2007

Es wird die strahlende Rekombination elektronenstrahlangeregter heißer Träger bei der Temperatur des flüssigen Neons untersucht. Dabei wird ein Lumineszenzpeak oberhalb der freien Exzitonenenergie bei 3,495 eV gefunden, das wahrscheinlich auf einen Band‐Band‐Übergang freier Träger zurückzuführen ist. Die hohe Trägerkonzentration erzeugt ein thermisches Quasigleichgewicht im Elektronensystem, das durch eine verallgemeinerte Temperatur Te beschrieben werden kann. Diese Temperatur ist höher als die Gittertemperatur und wächst mit steigender Anregungsdichte. Aus der Abhängigkeit der Temperatur Te von der erzeugten Überschußladungsträgerdichte ergibt sich als dominanter Energieverlustmechanismus die polar‐optische Streuung.
Punktdefekte und Überstrukturerscheinungen in CdSe‐Epitaxieschichten
Authors: Däweritz L.
Published: July 2007

An im Hochvakuum aufgedampften CdSe‐Schichten auf CaF2‐Spaltflächen werden Transmissionselektronenbeugungsdiagramme mit Überstrukturreflexen beobachtet. Diese Überstrukturerscheinungen werden durch eine geordnete Verteilung von Punktdefekten erklärt und mit Berechnungen nach der Debye‐Hückel‐Theorie verglichen. Es wird gezeigt, daß infolge von Abweichungen von der stöchiometrischen Zusammensetzung das Auftreten der Zinkblende‐ und Wurtzitstruktur in vielen Fällen nicht allein auf der Basis der dielektrischen Strukturtheorie nach PHILLIPS und VAN VECHTEN erklärt werden kann.
Zum Einfluß der Diffusion auf Keimbildung und Wachstum bei der Kristallzüchtung aus der Gasphase
Authors: Kersten F. , Hamann C.
Published: July 2007

Charakteristika des Wachstums bei der Kristallzüchtung durch Sublimation/Desublimation im Inertgas haben ihre Ursache in der Diffusion des Nährstoffes zur Wachstumsfront, Für zwei idealisierte Grenzfälle werden die Diffusionsfelder berechnet und für die bei praktischen Züchtungen vorliegenden Bedingungen diskutiert.
Wachstum von Graphitkristallen in kohlenstoffhaltigen Eisenschmelzen bei höheren Überschreitungen
Authors: Herfurth K. , Ziegler E.
Published: July 2007

Wachstumsgeschwindigkeiten für die Basis‐ und die Prismenflächen von Graphitkristallen werden in Abhängigkeit von der Überschreitung unter der Voraussetzung berechnet, daß die Flächen bei hohen Überschreitungen über zweidimensionale Keimbildung aus einer Eisen—Kohlenstoff‐Schmelze wachsen. Es zeigt sich, daß in der Nähe des Gleichgewichts Prismenflächen schneller als Basisflächen wachsen. Bei hohen Überschreitungen kehrt sich dagegen das Verhältnis der Wachstumsgeschwindigkeiten um. Diese Ergebnisse sind geeignet, die unterschiedlichen Graphitformen in Gußeisen zu erklären.
Effect of preliminary processing on the parameters of deformation curves and structure of slip lines of MgO crystals
Authors: Alybaeva N. R. , Berezhkova G. V. , Govorkov V. G.
Published: July 2007

The effect of annealing, chemical and mechanical polishing on the form of stress‐strain curves, the values of yield strength and work hardening rates and on the density and structure of slip lines was investigated.
Supersaturation and crystal size distribution changes during the precipitation of Nickel ammonium sulphate hexahydrate
Authors: Mullin J. W. , Ang H.‐M. , Ang H.‐M.
Published: July 2007

The desupersaturation of nickel ammonium sulphate aqueous solutions, during the precipitation of the hydrated salt, has been followed by refractive index measurements. The addition of seed crystals has a considerable effect on the desupersaturation process: the induction and latent periods and the crystal size distribution are all greatly reduced.

The precipitated crystal size follows V. WEIMARN'S rules, viz, the median size (a) passes through a maximum with increasing supersaturation for a given crystallization time, and (b) decreases with increasing supersaturation, for precipitations which have virtually ceased. The crystal yield increases with both supersaturation and time, but the size distribution remains fairly constant with time for supersaturations, S > 2.
LEED‐AES‐Untersuchungen der Oxydation von austenitischen Cr‐Ni‐Stählen an der (100)‐Ebene
Authors: Adolphi B. , Müssig H.‐J.
Published: July 2007

Es wird die Oxydation von austenitischem Cr–Ni‐Stahl an der (100)‐Fläche untersucht. Der betrachtete Temperaturbereich reicht von Raumtemperatur bis zu 1000°C. Die Oxydation beginnt mit der Bildung von Chromoxid (Cr2O3). Anschließend entsteht Eisenoxid (Fe3O4), das im Laufe der Reaktion das Chromoxid zudeckt. Bei 500°C zerfällt Fe3O4 und wächst die Chromoxidschicht. Bei 700°C beobachtet man im LEED‐Bild Cr2O3(111) und ab 750°C kann man darauf FeO(111) nachweisen. Ab 1000°C ist die Oxidschicht zerstört. Alle angeführten Oxide wachsen inselförmig.
Matrixprobleme in der Augerelektronenspektroskopie von Cu‐Ag‐Legierungen verschiedener Zusammensetzung
Authors: Streubel P. , Berndt H. , Meisel A.
Published: July 2007

Anhand der beiden Grenzfälle einer Cu–Ag‐Legierung mit sehr großem Ag‐ bzw. Cu‐Gehalt konnte die Konzentrationsabhängigkeit der matrixspezifischen Parameter Rückstreufaktor r und mittlere Austrittstiefe λ nachgewiesen werden. Die Quotienten rCu/rAg bzw. λCu/λAg unterscheiden sich für diese beiden Grenzfälle um etwa 4% bzw. 2%. Der Rückstreufaktor r wurde durch numerische Integration aus Rückstreuverteilungskurve Nr(E) und Ionisierungsquerschnitt σ erhalten. – Der berechnete Empfindlichkeitsfaktor SCu zeigt ebenfalls eine Konzentrationsabhängigkeit. Die Werte für SCu weichen von einem Grenzfall zum anderen um etwa 6% ab. – Der Vergleich der berechneten Empfindlichkeitsfaktoren SCu mit experimentell bestimmten Augerergiebigkeitsfaktroen 1/KCu von Braun und Färber verdeutlicht neben der Konzentrationsabhängigkeit den starken Einfluß der Probenvorbehandlungsmethoden auf 1/KCu. Die Feststellung von Färber für diesen Fall, daß das Sputtern als Vorbehandlung von einem Zweiphasensystem wie der Cu–Ag‐Legierung am besten geeignet ist, konnte bestätigt werden.
Einfluß der mechanischen Aktivierung auf Struktur und Reaktivität apatitischer Phosphate
Authors: Pöthig R. , Dünkel L. , Paudert R. , Harenz H. , Grimmer A.‐R.
Published: July 2007

Die mechanische Aktivierung von Apatiten führt zur Erhöhung der Lösbarkeit in Citronensäure und alkalischer Ammoncitratlösung. Die Textur‐ und Strukturveränderungen des Festkörpers werden als Ursachen für die Lösbarkeitserhöhung dargestellt.
Laue three beam cases with X‐rays: Experimental and theoretical examples
Authors: Hildebrandt G.
Published: July 2007

Experimental observations under conditions, where X‐rays are simultaneously diffracted on two net‐planes („three beam case”︁) in transmission, are reported for two examples where 111 netplanes are involved. The fundamentals of the theoretical treatment are given for the same two cases.
Zur Struktur mechanisch erzeugter amorpher Quarzschichten
Authors: Steinike U. , Müller B. , Ebert I. , Hennig H.‐P.
Published: July 2007

Durch die mechanische Bearbeitung in einer Schwingmühle wird eine Amorphisierung des Quarzes erreicht, indem die Fernordnung aufgehoben wird. Die durch den Quarz vorgeprägte Nahordnung bleibt jedoch für r < 0.65 nm zu rund 50% bestehen. Die Struktur des durch mechanische Bearbeitung zerstörten Quarzes unterscheidet sich im Nahordnungsbereich von der der amorphen Kieselsäure. Die Entstehung von Sauerstoffdefektelektronen‐Zentren, die an die O2‐Anwesenheit gebunden sind, wird im Zusammenhang mit der mechanisch zerstörten Quarzstruktur diskutiert.
Changes in Structure of ZnS Crystals Due to Mechanical Stresses
Authors: Farkas‐Jahnke M. , Gács P.
Published: July 2007

Using the direct X‐ray diffraction method which was worked out for the case of lattices built up of translationally equivalent layers for the determination of the rat of occurrences of structure elements in crystal regions consisting of 3, 4 and 5 layers, respectively, structure changes in ZnS crystals due to mechanical stresses were investigated.

Forces acting parallel to the [110] direction induced a decrease in the number of stackings containing hexagonal elements and increase in the number of cubic stackings. A lattice region of a ZnS crystal having originally pure 4 H structure became heavily stacking faulted when polished parallel to the (110) plane; repeated polishing results in a twinned cubic structure.
Growth of defect‐free Sr1−xBaxNb2O6 (SBN) crystals
Authors: Reiche P. , Schalge R. , Bohm J. , Schultze D.
Published: July 2007

SBN single crystals are grown by the Czochralski technique. Growth defects (striations, dislocations, twin lamellae) are investigated as depending on growth conditions. Crystals almost free from growth defects and applicable to optical devices are prepared by an optimized growth technology.
The Czochralski growth of doped bismuth‐germanium oxide (BGO) and bismuth‐silicon oxide (BSO) single crystals
Authors: Łukasiewicz T. , Żmija J.
Published: July 2007

Doped single crystals of BGO and BSO with Cr, Mn, Cu, Ni have been grown. The conditions for the growth of doped single crystals by the Czochralski method have been determined, analyses of distributions of dopants in the crystals have been made. For the Mn, Cr, Cu, doped crystals changes of coloration after illumination with visible light have been observed.
Non‐crystallographic symmetries in the superstructure of (NH4)2ZnCl4
Authors: Warczewski J.
Published: July 2007

The modulation vector turned out to be equal 1/4. The lattice constants of the orthorhombic superstructure are determined: a = 12.6197(16) Å, b = 7.2107(81) Å, c = 4 × 9.2746(15) Å. The two of the four absences rules are interpreted as corresponding to the non‐crystallographic symmetries:
equation image

The space group P 21cn is determined on the basis of the single crystal X‐ray pictures taking into account the experimental evidence of pyroelectricity in (NH4)2ZnCl4.
Isotopic method for studying the kinetics of crystal growth
Authors: Misztal S. , Kołek A. , Koch R.
Published: July 2007

An experimental method for studying the kinetics of crystal growth based on the knowledge of crystal size distribution in the crystallizer is presented. Residence time distribution was determined using the radioactive isotopes technique. The method was employed to determine the magnesium sulphate growth kinetics in high temperature conditions.
Qualitative and quantitative determination of X‐ray trajectories
Authors: Dietrich B. , Härtwig J.
Published: July 2007

X‐Ray trajectories are qualitatively determined only from the behaviour of the potential (of the lattice distance) in crystals with x‐dependent deformation gradients. the quantitative calculations show the varying degrees of sensitivity of X‐ray trajectories to deformation for different radiations, different orders of reflection and different maximum values of relative change of lattice distance.
Crystal growth from concentrated aqueous solutions of calcium nitrate
Authors: Paćk P. , Oesterreicherová H.
Published: July 2007

The crystal growth kinetics was studied in the system of calcium nitrate – water at concentrations 14.3, 11.1, and 9.1 mole% of Ca(NO3)2 within the supercooling region ΔT = 0–65 K. The mechanism of the growth was suggested and the concentration dependence of the crystal growth rate was discussed.
Anomalous behaviour of LaMnO3 with small structure distortions in magnetic phase transitions range
Authors: Sirota N. N. , Pavlov V. I. , Bogush A. K. , Karvay A. P.
Published: July 2007

The magnetic field effect on conductivity and intensity of the magnetic neutron diffraction reflections as well as magnetization of lanthanum manganite with different crystal lattice distortions in the ferromagnetic‐paramagnetic transitions range are investigated. It is shown that in the investigated samples near the paramagnetic‐ferromagnetic transition temperature at H = 0 there exists a relatively wide transition range where the magnetic ordering occurs with a relatively small external magnetic field applied.
Bulk crystals of PbTe synthesized by the iodide method
Authors: Karagiozov L. , Trifonova E. P. , Yakimova R. T.
Published: July 2007

Bulk crystals have been prepared for the first time from PbTe synthesized by low‐temperature iodide method. Their basic structural, physico‐chemical and electrical parameters as a result of certain technology conditions have been investigated.
Identification of the multi‐input box‐Jenkins transfer function model
Authors: Edlund Per‐Olov
Published: July 2007

In this paper different ways to identify the order of the Box–Jenkins transfer function model are discussed. The discussion concerns estimation of the impulse response weight function in the case of more than one input variable. It is found that most of the existing methods are either unsuitable when there is more than one input variable, or expensive or difficult to use. To overcome these deficiencies an extended regression method is proposed. The new method is based on the solution of some problems in connection with the use of the regression method. The impulse response weights are estimated by a biased regression estimator on variables transformed with respect to the noise model. To test the new approach a small simulation experiment has been performed. The results from the simulations indicate that the proposed method may be of value to the practitioner.
Forecasting and the database: An analysis of databases for international business
Authors: Rice Gillian , Mahmoud Essam
Published: July 2007

A major consideration in the selection of a forecasting method for a specific situation is the type of pattern in the data. Before the data pattern is identified, the forecaster must recognize the dependence of any forecasting method upon the accompanying reliable database. This issue is discussed in the paper with reference to databases for international business.
Application of the linear partial information model to forecasting the Swiss timber market
Authors: Zimmermann A. , Zweifel P. , Kofler E.
Published: July 2007

Most often, statistical analyses only provide partial information about the appropriateness of different models, structures and parameters which may underlie the dynamic process that has generated a time series. Linear partial information (LPI), in particular, consists of linear restrictions such as LPI: pa> pb, pa> pc where pa denotes the probability that structure a holds. Fuzzy information of this type can be put to use for decision‐making by LPI analysis. In this paper, LPI analysis is applied to answer the question of whether subsidizing price, given an abnormal disturbance on the timber market, would contribute to continuous forest management, a stated goal of Swiss environmental policy.