2,750 research outputs found
Entrepreneurial alertness and business model innovation in dynamic markets: international performance implications for SMEs
Acknowledgement This research was supported by Hankuk University of Foreign Studies Research Fund. This research was financially supported by Queen Mary University of London.Peer reviewedPublisher PD
Methane recovery efficiency in a submerged anaerobic membrane bioreactor (SAnMBR) treating sulphate-rich urban wastewater: Evaluation of methane losses with the effluent
The present paper presents a submerged anaerobic membrane bioreactor (SAnMBR) as a sustainable
approach for urban wastewater treatment at 33 and 20 C, since greenhouse gas emissions are reduced
and energy recovery is enhanced. Compared to other anaerobic systems, such as UASB reactors, the membrane
technology allows the use of biogas-assisted mixing which enhances the methane stripping from
the liquid phase bulk. The methane saturation index obtained for the whole period (1.00 ± 0.04) evidenced
that the equilibrium condition was reached and the methane loss with the effluent was reduced.
The methane recovery efficiency obtained at 20 C (53.6%) was slightly lower than at 33 C (57.4%) due to
a reduction of the treatment efficiency, as evidenced by the lower methane production and the higher
waste sludge per litre of treated wastewater. For both operational temperatures, the methane recovery
efficiency was strongly affected by the high sulphate concentration in the influent wastewater.This research work has been supported by the Spanish Research Foundation (CICYT Projects CTM2008-06809-C02-01 and CTM2008-06809-C02-02) and the Comunidad Valenciana Regional Government (GVACOMP2009-285), which are gratefully acknowledged.Gimenez, J.; MartĂ, N.; Ferrer, J.; Seco, A. (2012). Methane recovery efficiency in a submerged anaerobic membrane bioreactor (SAnMBR) treating sulphate-rich urban wastewater: Evaluation of methane losses with the effluent. Bioresource Technology. 118:67-72. https://doi.org/10.1016/j.biortech.2012.05.019S677211
Hunter-gatherer childrenâs object play and tool use: An ethnohistorical analysis
Learning to use, make, and modify tools is key to our speciesâ success. Researchers have hypothesized that play with objects may have a foundational role in the ontogeny of tool use and, over evolutionary timescales, in cumulative technological innovation. Yet, there are few systematic studies investigating childrenâs interactions with objects outside the post-industrialized West. Here, we survey the ethnohistorical record to uncover cross-cultural trends regarding hunter-gatherer childrenâs use of objects during play and instrumental activities. Our dataset, consisting of 434 observations of childrenâs toys and tools from 54 hunter-gatherer societies, reveals several salient trends: Most objects in our dataset are used in play. Children readily manufacture their own toys, such as dolls and shelters. Most of the objects that children interact with are constructed from multiple materials. Most of the objects in our dataset are full-sized or miniature versions of adult tools, reflecting learning for adult roles. Children also engage with objects related to child culture, primarily during play. Taken together, our findings show that hunter-gatherer children grow up playing, making, and learning with objects
The Non-Immune RIP-kb Mouse is a Useful Host for Islet Transplantation, as the Diabetes is Spontaneous, Mild and Predictable
Chemically-induced diabetic mice and spontaneously
diabetic NOD mice have been valuable
as recipients for experimental islet transplantation.
However, their maintenance often
requires parenteral insulin. Diabetogenic chemicals
can be cytotoxic to the hostâs immune system
and to other organs some of which are
often used as the transplant site. Procurement
of diabetic cohorts in the NOD mouse is problematic
due to variability in the age of disease
onset. We show that RIP-Kb mice, which spontaneously
develop non-immune diabetes due to
over-expression of the H-2Kb heavy chain in
beta cells, offer many advantages as islet transplant
recipients. Diabetes is predictable with a
relatively narrow range of onset (4 wk) and
blood glucose levels (23.0± 4.0 mmol/l for 39
males at 6 weeks of age). The diabetes is mild enough so that most diabetic mice can be maintained
to 40 weeks of age without parenteral
insulin. This consistency of diabetes avails that
outcomes of intervention can be interpreted
with confidence
Spatial mapping of band bending in semiconductor devices using in-situ quantum sensors
Band bending is a central concept in solid-state physics that arises from
local variations in charge distribution especially near semiconductor
interfaces and surfaces. Its precision measurement is vital in a variety of
contexts from the optimisation of field effect transistors to the engineering
of qubit devices with enhanced stability and coherence. Existing methods are
surface sensitive and are unable to probe band bending at depth from surface or
bulk charges related to crystal defects. Here we propose an in-situ method for
probing band bending in a semiconductor device by imaging an array of
atomic-sized quantum sensing defects to report on the local electric field. We
implement the concept using the nitrogen-vacancy centre in diamond, and map the
electric field at different depths under various surface terminations. We then
fabricate a two-terminal device based on the conductive two-dimensional hole
gas formed at a hydrogen-terminated diamond surface, and observe an unexpected
spatial modulation of the electric field attributed to a complex interplay
between charge injection and photo-ionisation effects. Our method opens the way
to three-dimensional mapping of band bending in diamond and other
semiconductors hosting suitable quantum sensors, combined with simultaneous
imaging of charge transport in complex operating devices.Comment: This is a pre-print of an article published in Nature Electronics.
The final authenticated version is available online at
https://dx.doi.org/10.1038/s41928-018-0130-
Preheating and Affleck-Dine leptogenesis after thermal inflation
Previously, we proposed a model of low energy Affleck-Dine leptogenesis in
the context of thermal inflation. The lepton asymmetry is generated at the end
of thermal inflation, which occurs at a relatively low energy scale with the
Hubble parameter somewhere in the range 1 \keV \lesssim H \lesssim 1 \MeV.
Thus Hubble damping will be ineffective in bringing the Affleck-Dine field into
the lepton conserving region near the origin, leaving the possibility that the
lepton number could be washed out. Previously, we suggested that preheating
could damp the amplitude of the Affleck-Dine field allowing conservation of the
lepton number. In this paper, we demonstrate numerically that preheating does
efficiently damp the amplitude of the Affleck-Dine field and that the lepton
number is conserved as the result. In addition to demonstrating a crucial
aspect of our model, it also opens the more general possibility of low energy
Affleck-Dine baryogenesis.Comment: 38 pages, 17 figure
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