8,168 research outputs found
Imaging Pulsed Laser Deposition oxide growth by in-situ Atomic Force Microscopy
To visualize the topography of thin oxide films during growth, thereby
enabling to study its growth behavior quasi real-time, we have designed and
integrated an atomic force microscope (AFM) in a pulsed laser deposition (PLD)
vacuum setup. The AFM scanner and PLD target are integrated in a single support
frame, combined with a fast sample transfer method, such that in-situ
microscopy can be utilized after subsequent deposition pulses. The in-situ
microscope can be operated from room temperature (RT) up to 700C and at
(process) pressures ranging from the vacuum base pressure of 10 mbar up
to 1 mbar, typical PLD conditions for the growth of oxide films. The
performance of this instrument is demonstrated by resolving unit cell height
surface steps and surface topography under typical oxide PLD growth conditions.Comment: 8 pages, 8 figure
Local Environment of Ferromagnetically Ordered Mn in Epitaxial InMnAs
The magnetic properties of the ferromagnetic semiconductor In0.98Mn0.02As
were characterized by x-ray absorption spectroscopy and x-ray magnetic circular
dichroism. The Mn exhibits an atomic-like L2,3 absorption spectrum that
indicates that the 3d states are highly localized. In addition, a large
dichroism at the Mn L2,3 edge was observed from 5-300 K at an applied field of
2T. A calculated spectrum assuming atomic Mn2+ yields the best agreement with
the experimental InMnAs spectrum. A comparison of the dichroism spectra of MnAs
and InMnAs show clear differences suggesting that the ferromagnetism observed
in InMnAs is not due to hexagonal MnAs clusters. The temperature dependence of
the dichroism indicates the presence of two ferromagnetic species, one with a
transition temperature of 30 K and another with a transition temperature in
excess of 300 K. The dichroism spectra are consistent with the assignment of
the low temperature species to random substitutional Mn and the high
temperature species to Mn near-neighbor pairs.Comment: 10 pages, 4 figures, accepted by Applied Physics Letter
Issues of alcohol safety in the Vologda oblast
The article presents the destructive social processes and threats to alcohol safety. The estimation of the basic indicators of production and consumption of alcoholic beverages in the region. The study of the international experience of regulate alcohol consumption, the necessity of toughening of state regulation of turnover of alcoholic products
The RESET Mindset Model applied on decreasing antibiotic usage in dairy cattle in the Netherlands
This article analyses sanctuary initiatives intended to change the situation of ‘irregularised residents’. Through fieldwork, three main activities are identified: assistance for welfare services, alternatives to inaccessible services, and inventing new ways of organising togetherness in the city. The role of activists in the initiatives links to discussions within Critical Human Rights literature, which emphasise the anti-institutionalist origins of rights. Yet, a complex interplay also plays out through co-current resistance against the state’s migration policing and collaboration with city-level state agencies. Understanding this complex process is important to improving knowledge of both the politics of sanctuary and human rights
What’s in a name? Politicising wastewater reuse in irrigated agriculture
Wastewater is increasingly being reused as a solution to water scarcity in agriculture. This article
combines a literature review with an ethnographic study of water reuse in Dar es Salaam, Tanzania, to explore the
field of wastewater reuse and what it is made to represent. The academic literature largely focuses on the practical
challenges of wastewater treatment, while underlying political dynamics that contextualise the planning of, and
control over, water flows remain largely unaddressed. Because people seek to take control over water through the
manipulation of flows and qualities, wastewater reuse is inherently political. The study of water reuse practices in
Dar es Salaam shows how water quality decline is co-produced with processes of urbanisation that cause
inequalities in the urban waterscape. Farmers are subject to changes in the physical characteristics and normative
understandings of the urban water system, yet do not have the power to reconfigure these to their own ends or
challenge the way that their practices are portrayed. This paper shows the importance of politicising wastewater
reuse and calls for a more diverse and emancipatory understanding of, and response to, water reuse in agriculture
through interdisciplinary research and the collaborative production of knowledge and interventions
Formation of viable cell fragments by treatment with colchicine
Time-lapse cinematography of human fibroblasts revealed that mitotic cells separated into numerous cell fragments containing varying amounts of chromatin and cytoplasm when treated with colchicine. As cell fragments were very loosely attached to the surface of the culture vessel during their formation, they could be easily detached like mitotic cells by gently shaking the vessel and thus separated from normal interphase cells. Fragments obtained by this procedure were able to exclude trypan blue indicating, therefore, an intact cell membrane. When placed into Petri dishes many of them attached to and even spread out on the surface. Five hours later the majority of the attached fragments incorporated [3H]leucine. Time-lapse films showed that fragments were able to extend and retract pseudopodia at least for several hours after their formation. Although the fragments degenerated within a few days, in the present experiments the possibility was not excluded that fragments which had lost only a very small amount of chromatin and cytoplasm survived for longer periods of time. The observations clearly indicate viability of many newly formed fragments
Is there a reentrant glass in binary mixtures?
By employing computer simulations for a model binary mixture, we show that a
reentrant glass transition upon adding a second component only occurs if the
ratio of the short-time mobilities between the glass-forming component
and the additive is sufficiently small. For , there is no
reentrant glass, even if the size asymmetry between the two components is
large, in accordance with two-component mode coupling theory. For , on the other hand, the reentrant glass is observed and reproduced only by
an effective one-component mode coupling theory.Comment: 4 pages, 3 figure
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