1,323 research outputs found
Mitigating the risk of extreme water scarcity and dependency: the case of Jordan
Jordan faces great internal water scarcity and pollution, conflict over trans-boundary waters, and strong dependency on external water resources through trade. This paper analyzes these issues and subsequently reviews options to reduce the risk of extreme water scarcity and dependency. Based on estimates of water footprint, water availability, and virtual water trade, we find that groundwater consumption is nearly double the groundwater availability, water pollution aggravates blue water scarcity, and Jordan’s external virtual water import dependency is 86%. The review of response options yields 10 ingredients for a strategy for Jordan to mitigate the risks of extreme water scarcity and dependency. With respect to these ingredients, Jordan’s current water policy requires a strong redirection towards water demand management. Actual implementation of the plans in the national water strategy (against existing oppositions) would be a first step. However, more attention should be paid to reducing water demand by changing the consumption pattern of Jordanian consumers. Moreover, unsustainable exploitation of the fossil Disi aquifer should soon be halted and planned desalination projects require careful consideration regarding the sustainability of their energy suppl
Potential solar axion signatures in X-ray observations with the XMM-Newton observatory
The soft X-ray flux produced by solar axions in the Earth's magnetic field is
evaluated in the context of ESA's XMM-Newton observatory. Recent calculations
of the scattering of axion-conversion X-rays suggest that the sunward
magnetosphere could be an observable source of 0.2-10 keV photons. For
XMM-Newton, any conversion X-ray intensity will be seasonally modulated by
virtue of the changing visibility of the sunward magnetic field region. A
simple model of the geomagnetic field is combined with the ephemeris of
XMM-Newton to predict the seasonal variation of the conversion X-ray intensity.
This model is compared with stacked XMM-Newton blank sky datasets from which
point sources have been systematically removed. Remarkably, a seasonally
varying X-ray background signal is observed. The EPIC count rates are in the
ratio of their X-ray grasps, indicating a non-instrumental, external photon
origin, with significances of 11(pn), 4(MOS1) and 5(MOS2) sigma. After
examining the constituent observations spatially, temporally and in terms of
the cosmic X-ray background, we conclude that this variable signal is
consistent with the conversion of solar axions in the Earth's magnetic field.
The spectrum is consistent with a solar axion spectrum dominated by
bremsstrahlung- and Compton-like processes, i.e. axion-electron coupling
dominates over axion-photon coupling and the peak of the axion spectrum is
below 1 keV. A value of 2.2e-22 /GeV is derived for the product of the
axion-photon and axion-electron coupling constants, for an axion mass in the
micro-eV range. Comparisons with limits derived from white dwarf cooling may
not be applicable, as these refer to axions in the 0.01 eV range. Preliminary
results are given of a search for axion-conversion X-ray lines, in particular
the predicted features due to silicon, sulphur and iron in the solar core, and
the 14.4 keV transition line from 57Fe.Comment: Accepted for publication in MNRAS. 67 pages total, including 39
figures, 6 table
Trapped at Work: The Barriers Model of Abusive Supervision.
While research on abusive supervision is thriving, we still know very little about the sustained nature of the phenomenon. Additionally, most papers focusing on the prolonged character of the detrimental relational dynamic take a within-dyad perspective, largely ignoring within-person, group or other external influences. Addressing these gaps in the literature, we introduce the Barriers Model of Abusive Supervision. This model posits a hierarchically organized set of obstacles that make it difficult for followers to escape the abusive supervisor, explaining why abuse can continue over long periods of time. Specifically, we present an onion-shaped model in which the follower has a central position with each subsequent layer representing a more external cluster of barriers to leaving the abusive supervisor. Ranging from external to internal, these layers are: Barriers in the larger societal context (Layer 1; e.g., ambiguous laws), barriers in the organizational context (Layer 2; e.g., unclear policies), barriers due to the abusive supervisor (Layer 3; e.g., isolating followers), and barriers within the abused follower (Layer 4; e.g., implicit leadership theories). We hope that our model inspires future research on the sustained nature of abusive supervision and provides practitioners with the necessary background information to help abused followers escape their supervisors
Dynamics of trimming the content of face representations for categorization in the brain
To understand visual cognition, it is imperative to determine when, how and with what information the human brain categorizes the visual input. Visual categorization consistently involves at least an early and a late stage: the occipito-temporal N170 event related potential related to stimulus encoding and the parietal P300 involved in perceptual decisions. Here we sought to understand how the brain globally transforms its representations of face categories from their early encoding to the later decision stage over the 400 ms time window encompassing the N170 and P300 brain events. We applied classification image techniques to the behavioral and electroencephalographic data of three observers who categorized seven facial expressions of emotion and report two main findings: (1) Over the 400 ms time course, processing of facial features initially spreads bilaterally across the left and right occipito-temporal regions to dynamically converge onto the centro-parietal region; (2) Concurrently, information processing gradually shifts from encoding common face features across all spatial scales (e.g. the eyes) to representing only the finer scales of the diagnostic features that are richer in useful information for behavior (e.g. the wide opened eyes in 'fear'; the detailed mouth in 'happy'). Our findings suggest that the brain refines its diagnostic representations of visual categories over the first 400 ms of processing by trimming a thorough encoding of features over the N170, to leave only the detailed information important for perceptual decisions over the P300
Ad Braat, bestuivingsimker bij een zaadteeltbedrijf
Een interview met een beroepsimker, werkzaam op het zaadteeltbedrijf Nunhems Zadwn in Haelen (Limburg). Hij verzorgt de bijen en andere insekten die ingezet worden bij de bestuiving van groentegewasse
Cracking the code of oscillatory activity
Neural oscillations are ubiquitous measurements of cognitive processes and dynamic routing and gating of information. The fundamental and so far unresolved problem for neuroscience remains to understand how oscillatory activity in the brain codes information for human cognition. In a biologically relevant cognitive task, we instructed six human observers to categorize facial expressions of emotion while we measured the observers' EEG. We combined state-of-the-art stimulus control with statistical information theory analysis to quantify how the three parameters of oscillations (i.e., power, phase, and frequency) code the visual information relevant for behavior in a cognitive task. We make three points: First, we demonstrate that phase codes considerably more information (2.4 times) relating to the cognitive task than power. Second, we show that the conjunction of power and phase coding reflects detailed visual features relevant for behavioral response-that is, features of facial expressions predicted by behavior. Third, we demonstrate, in analogy to communication technology, that oscillatory frequencies in the brain multiplex the coding of visual features, increasing coding capacity. Together, our findings about the fundamental coding properties of neural oscillations will redirect the research agenda in neuroscience by establishing the differential role of frequency, phase, and amplitude in coding behaviorally relevant information in the brai
MYRRHA: A multipurpose nuclear research facility
MYRRHA (Multi-purpose hYbrid Research Reactor for High-tech Applications) is a multipurpose research facility currently being developed at SCK•CEN. MYRRHA is based on the ADS (Accelerator Driven System) concept where a proton accelerator, a spallation target and a subcritical reactor are coupled. MYRRHA will demonstrate the ADS full concept by coupling these three components at a reasonable power level to allow operation feedback.
As a flexible irradiation facility, the MYRRHA research facility will be able to work in both critical as subcritical modes. In this way, MYRRHA will allow fuel developments for innovative reactor systems, material developments for GEN IV and fusion reactors, and radioisotope production for medical and industrial applications. MYRRHA will be cooled by lead-bismuth eutectic and will play an important role in the development of the Pb-alloys technology needed for the LFR (Lead Fast Reactor) GEN IV concept.
MYRRHA will also contribute to the study of partitioning and transmutation of high-level waste. Transmutation of minor actinides (MA) can be completed in an efficient way in fast neutron spectrum facilities, so both critical reactors and subcritical ADS are potential candidates as dedicated transmutation systems. However critical reactors heavily loaded with fuel containing large amounts of MA pose reactivity control problems, and thus safety problems. A subcritical ADS operates in a flexible and safe manner, even with a core loading containing a high amount of MA leading to a high transmutation rate.
In this paper, the most recent developments in the design of the MYRRHA facility are presented
Aging of large area CsI photocathodes for the ALICE HMPID prototypes
The ALICE HMPID RICH detector is equipped with CsI photocathodes in a MWPC for the detection of Cherenkov photons. The long term operational experience with large area CsI photocathodes will be described. The RICH prototypes have shown a very high stability of operation and performance, at a gain of 10 \5 and with rates up to 2x10 \4 cm-2 s-1. When exposure to air has been avoided, no degradation of the CsI quantum efficiency has been observed on photocathodes periodically exposed to test-beams over 7 years, corresponding to local integrated charge densities of ~ 1 mC cm-2. The results of limited exposures to oxygen and humidity will also be presented
Can crop residues provide fuel for future transport? Limited global residue bioethanol potentials and large associated land, water and carbon footprints
Bioethanol production from non-crop based lignocellulosic material has reached the commercial scale and is advocated as a possible solution to decarbonize the transport sector. This study evaluates how much presently used transport related fossil fuels can be replaced with lignocellulosic bioethanol using crop residues, calculates greenhouse gas emission savings, and determines lignocellulosic bioethanol's land, water, and carbon footprints. We estimate global bioethanol production potential from 123 crop residues in 192 countries and 20 territories under different environmental constraints (optimistic and realistic sustainable potentials) versus no constraints (theoretical potential) on residue availability. Previous studies on global bioethanol production potential from lignocellulosic material focused on one or few biomass feedstocks, and excluded (un)constrained residue availability scenarios. Our results suggest the global net lignocellulosic bioethanol output ranges from 7.1 to 34.0 EJ per annum replacing between 7% and 31% of oil products for transport yielding relative emission savings of 338 megatonne (Mt; 70%) to 1836 Mt (79%). Emission savings range from 4% to 23% of total transport emissions in the realistic sustainable versus theoretical potential. Land, water and carbon footprints of net bioethanol vary between potentials, countries/territories, and feedstocks, but overall exceed footprints of conventional bioethanol. Averaged footprints range between 0.14 and 0.24 m2 land per megajoule (MJ−1), 74–120 L water MJ−1, and 28–44 g CO2 equivalent MJ−1, with smaller footprints in the theoretical potential caused by the exclusion of secondary residues and low price of alternative biomass chains in the sustainable potential
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