6,968 research outputs found
Thermopower-based hot electron thermometry of helium surface states at 1.6 K
We have developed a method to probe the temperature of surface state
electrons (SSE) above a superfluid Helium-4 surface using the Seebeck effect.
In contrast to previously used SSE thermometry, this technique does not require
detailed knowledge of the non-linear mobility. We demonstrate the use of this
method by measuring energy relaxation of SSE at 1.6 K in a microchannel device
with 0.6\:\mu\mbox{m} deep helium. In this regime, both vapor atom scattering
and 2-ripplon scattering contribute to energy relaxation to which we compare
our measurements. We conclude that this technique provides a reliable measure
of electron temperature while requiring a less detailed understanding of the
electron interactions with the environment than previously utilized thermometry
techniques
‘We don’t deal with courts’: cooperation and alternative institutions shaping exporting relationships of small and medium-sized enterprises in Ghana
Through an investigation of small and medium sized enterprises (SMEs) exporting in contexts which lack a formalised institutional environment in a less developed country, this article shows how entrepreneurs cope with institutional deficiency. By drawing on an analysis of 12 SMEs exporting from Ghana to other West African countries, the findings reveal how entrepreneurs and their organisations avoid recourse to the courts and instead, use culturally specific relationships to settle disputes when exporting. Institutional forms operating in parallel to the formal legal system are examined. These are shown to be hybrid forms drawing on traditional cultural institutions such as chieftaincy and religion, combined with forms of corporations and cooperatives. Assumptions around the different roles of family and kinship also are explored. The study contributes to the ongoing development of a theoretical understanding on trust and relationship building in international entrepreneurship, and the importance of understanding cultural context
Beyond green niches? Growth strategies of environmentally-motivated social enterprises
The article examines the strategies by which environmentally-motivated social enterprises seek to scale up their positive impacts, drawing on a theoretical understanding of the role of entrepreneurial agency in transitions to a more sustainable economy and society. Case study evidence is used to explore different forms of enterprise growth, contributions to economic, environmental and social value, and the capabilities involved in their realisation. A typology of three distinct approaches or modes is introduced to help explain orientations and strategies that reflect both conventional conceptions of growth and alternative ways of growing social and environmental value. The role of values, capabilities and relational learning in shaping strategies and addressing the tensions and challenges encountered within each category is highlighted
Reevaluation of the normative minerals of Sonora Pass rock standards - University of Nevada reports 7 and 12
Chemical analyses and normative minerals of Nevada mountain pass rock
Social enterprises and their ecosystems in Europe
Social enterprises present an alternative to business-as-usual with their combination of core social and environmental objectives being addressed through commercial approaches. In this way they present an alternative avenue for a sustainable prosperity that is not driven by profit but rather focused on flourishing and living within ecological limits. In the UK, there has been particular interest and support for the creation of start-ups and the scaling of existing social enterprises. The term social enterprise has been in use in the UK since the 1970s, and the current approaches are shaped by the philanthropic traditions of charities, the cooperative traditions of democratic governance, and cultures of socially responsible business. The UK social enterprise movement was given a boost by the pioneering public policies and approaches in the 1990s, including various support programmes, the introduction of a new legal form and investment funds. Since 2010 there has been a focus of policy on encouraging social investment funds and mutual social enterprise ‘spin-outs’ from the public sector. However, the context of public sector austerity has seen a considerable decline in overall spending across the UK in recent years, with the exception of Scotlan
Proposal for manipulating and detecting spin and orbital states of trapped electrons on helium using cavity quantum electrodynamics
We propose to couple an on-chip high finesse superconducting cavity to the
lateral-motion and spin state of a single electron trapped on the surface of
superfluid helium. We estimate the motional coherence times to exceed 15
microseconds, while energy will be coherently exchanged with the cavity photons
in less than 10 nanoseconds for charge states and faster than 1 microsecond for
spin states, making the system attractive for quantum information processing
and cavity quantum electrodynamics experiments. Strong interaction with cavity
photons will provide the means for both nondestructive readout and coupling of
distant electrons.Comment: 4 pages, 3 figures, supplemental material
Implementing democratic governance and ownership: the interplay of structure and culture in public service social enterprises
We examine the implementation of governance arrangements to extend ownership and control to employees and community stakeholders in social enterprises. Evidence from a sample of newly created public service social enterprises in England shows how the realisation of democratic ideals involves a gradual and often challenging process. Different outcomes are explained in terms of an interplay between the legal forms and representational mechanisms adopted and the enabling role of organisational culture. The paper contributes an analytic framework that captures the range of possible outcomes in terms of stakeholder versus stewardship forms of representation, and the cultural-psychological dimension of ownership. Organisations may find themselves at different stages in the journey towards the realisation of democratic ownership and governance. Conclusions are drawn for the field of social enterprise and non-profit research
'Social enterprise spin-outs': an institutional analysis of their emergence and potential
The recent phenomenon of public sector ‘social enterprise spin-outs’ is examined in order to critically assess their nature and innovative potential as providers of public services. The study utilises a theoretical model of institutional creation and change which incorporates key characteristics of ‘corporate spin-outs’ and ‘university spin-outs’ to facilitate the examination of their public sector counterparts, drawing on interview evidence from 30 newly-established social enterprise providers of health and care services in England. A main contribution of the paper is to provide a conceptual framework which sheds light on the strengths and potential vulnerabilities of social enterprise spin-outs as novel organisations that span the public, private and civil society sectors
Molecular, chemical and morphological evidence for hematite biogenicity at the Quaternary Cape Vani Mn-(Ba-Fe) deposit, Milos, Greece
Η γένεση ιζηματογενών πετρωμάτων πλούσιων σε σίδηρο, κυρίως αιματίτη, μέσω βιολογικών ή αβιοτικών διεργασιών, η κάποιου συνδυασμού αυτών, παραμένει άλυτο επιστημονικό πρόβλημα. Στην εργασία αυτή χρησιμοποιήσαμε έναν συνδυασμό αναλυτικών μεθόδων που συμπεριλαμβάνουν οπτική μικροσκοπία, ηλεκτρονική μικροσκοπία σάρωσης και μικροανάλυση (SEM-EDS), φασματοσκοπία Raman και φασματομετρία μάζας χρόνου πτήσης δευτερογενών ηλεκτρονίων (time-of-flight secondary ion mass spectrometry, TOF-SIMS), για να προσδιορίσουμε την χωρική κατανομή και την σύσταση εν δυνάμει γεωβιολογικών δεικτών (π.χ. μικροβιακά μικροαπολιθώματα, ιχνοστοιχεία, οργανικές ιοντικές ενώσεις) σε αιματιτικούς μικροστρωματόλιθους και μικροδομές από αιματίτη που μοιάζουν με oncolites (ονκόλιθους). Οι μικροδομές αυτές προσδιορίστηκαν σε υλικό πλούσιο σε σίδηρο που αποτελεί συνδετικό υλικό παράλιου κροκαλοπαγούς Τεταρτογενούς ηλικίας από την ευρύτερη περιοχή του ακρωτηρίου Βάνι, στη ΒΔ Μήλο. Ο προσδιορισμός μορφολογικών, χημικών και οργανικών μοριακών ιοντικών βιοδομών σε συνδυασμό με πιθανά μικροαπολιθώματα από αιματίτη, υποδηλώνουν μικροβιακή μεσολάβηση στον σχηματισμό των τελευταίων, και υποδεικνύουν ότι μικροστρωματόλιθοι από αιματίτη μπορεί να χρησιμοποιηθούν ως βιοδείκτες για τη ύπαρξη σιδηρούχων βίο- υλικών στη Γη, και για την ανίχνευση τους σε εξωγήινα υλικά. Η μελέτη των αιματιτικών μικροστρωματόλιθων του ακρωτηρίου Βάνι μπορεί να συμβάλει στην κατανόηση των λειτουργιών των μικροοργανισμών στην γένεση τόσο σύγχρονων όσο και παλαιών κοιτασμάτων σιδήρου.Many aspects of the biotic or abiotic origin of iron-rich sedimentary rocks consisting mainly of hematite, an important indicator for exobiology, remain unresolved. Here, we use combined optical microscopy, scanning electron microscopy and energy dispersive X-ray spectrometry (SEM-EDS), Raman spectroscopy and time-of-flight secondary ion mass spectrometry (TOF-SIMS), to image the spatial distribution, and determine the composition, of potential biogenic markers (microbial microfossils, trace elements, organic ion species) in hematitemicrostromatolites and oncolite-like microstructures. These structures are identified in iron-rich material cementing a Quaternary fossil-beach conglomerate deposit in the Cape Vani area, NW Milos Island, Greece. The combined detection of morphological, chemical, and molecular organic-ion, biomarkers closely associated with possible hematite microfossils within microstromatolite laminae, strongly supports microbial mediation for their formation, and indicates that hematitic microlamination may be used as a biosignature for Fe-rich biomats on Earth and for their detection in extra-terrestrial materials. The Cape Vani hematitemicrostromatolites may contribute to growing our understanding of the function of microorganisms in the genesis of modern and ancient Fe deposits
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