1,304 research outputs found
Towards transition management of European water resources
Global change fundamentally changes the nature of water-related problems. We will
illustrate this by showing how perceptions of the water-problems in the Netherlands
have shifted in the past four decades. The nature of water-related problems changed
from a technical problem’ to a so-called ‘persistent’ problem, characterized by
plurality, uncertainty and complexity. Although integrated water resource
management (IWRM) has been advocated to cope with this type of problem, the
complexity of the transition process towards such a water management regime is
often underestimated. Therefore, transition management is needed in the water
sector. Transition management theory is presented and applied to the Dutch case.
Transition management strategies are suggested that would reinforce this transition.
Comparison between the European Water Framework Directive (WFD) and
transition management indicates that the Common Implementation Strategy (CIS) in
its current form is not sufficiently stimulating an innovation climate
Akt activation disrupts mammary acinar architecture and enhances proliferation in an mTOR-dependent manner
Activation of the serine/threonine kinase Akt/PKB positively impacts on three cellular processes relevant to tumor progression: proliferation, survival, and cell size/growth. Using a three-dimensional culture model of MCF-10A mammary cells, we have examined how Akt influences the morphogenesis of polarized epithelial structures. Activation of a conditionally active variant of Akt elicits large, misshapen structures, which primarily arise from the combined effects of Akt on proliferation and cell size. Importantly, Akt activation amplifies proliferation during the early stages of morphogenesis, but cannot overcome signals suppressing proliferation in late-stage cultures. Akt also cooperates with oncoproteins such as cyclin D1 or HPV E7 to promote proliferation and morphogenesis in the absence of growth factors. Pharmacological inhibition of the Akt effector, mammalian target of rapamycin (mTOR), with rapamycin prevents the morphological disruption elicited by Akt activation, including its effect on cell size and number, and the cooperative effect of Akt on oncogene-driven proliferation, indicating that mTOR function is required for the multiple biological effects of Akt activation during morphogenesis
The transition in Dutch water management
Over the past decades the Dutch people have been confronted with severe waterrelated
problems, which are the result of an unsustainable water system, arising from
human interventions in the physical infrastructure of the water system and the water
management style. The claims of housing, industry, infrastructure and agriculture
have resulted in increasing pressure on the water system. The continuous subsidence
of soil and climate change has put pressure on the land. Hence, the nature and
magnitude of water-related problems have changed. Longitudinal research of
relevant national policy documents reveals that the water management regime has
changed its water management style over the past thirty years from a technocratic
scientific style towards an integral and participatory style. We have investigated if the
historical development in Dutch Water management can be characterized as a
transition. Based on longitudinal research through an integrated systems analysis,
document research and expert interviews, we have reconstructed the historical
narrative by using the transition concepts of multi-level and multi-phase. This
research indicates that the shift in Dutch Water management can be characterized as
a transition. This transition is currently in the take-off stage and near the acceleration
stage. This is a crucial stage as long as the considerable differences between the
strategic macro-vision and the practical implementation at the micro-level remains.
As long as these levels are not compatible (modulation), the transition will not be
completed successfully. Transition management as multi-level governance model
should therefore be adopted to facilitate the modulation
Transitiemanagement en duurzame ontwikkeling: co-evolutionaire sturing in het licht van complexiteit
This article presents a promising governance framework for 'persistent societal problems', based on the concept of transition management. This framework is based on the common notions from complexity theory and new forms of governance, that are folded into a new management paradigm. This management paradigm starts from complexity and uncertainty as drivers of societal innovation, not as obstacles that have to be fully controlled. Essential feature of transition management is the explicit coupling of content and process. The analysis (based on the presented analytical concepts) determines the transition management process: the management possibilities and instruments that are employed with regard to the presented management framework. The framework entails goals, activities, instruments and competences for the strategic, tactical and operational level. Which activities and actors are being involved depends on the phase of the transition
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Role for polo-like kinase 4 in mediation of cytokinesis.
The mitotic protein polo-like kinase 4 (PLK4) plays a critical role in centrosome duplication for cell division. By using immunofluorescence, we confirm that PLK4 is localized to centrosomes. In addition, we find that phospho-PLK4 (pPLK4) is cleaved and distributed to kinetochores (metaphase and anaphase), spindle midzone/cleavage furrow (anaphase and telophase), and midbody (cytokinesis) during cell division in immortalized epithelial cells as well as breast, ovarian, and colorectal cancer cells. The distribution of pPLK4 midzone/cleavage furrow and midbody positions pPLK4 to play a functional role in cytokinesis. Indeed, we found that inhibition of PLK4 kinase activity with a small-molecule inhibitor, CFI-400945, prevents translocation to the spindle midzone/cleavage furrow and prevents cellular abscission, leading to the generation of cells with polyploidy, increased numbers of duplicated centrosomes, and vulnerability to anaphase or mitotic catastrophe. The regulatory role of PLK4 in cytokinesis makes it a potential target for therapeutic intervention in appropriately selected cancers
Immunocytochemical localization of the neuron-specific form of the c-src gene product, pp60c-src(+), in rat brain
Neurons express high levels of a variant form of the c-src gene product, denoted pp60c-src(+), which contains a 6 amino acid insert in the amino-terminal half of the c-src protein. We have determined the localization of pp60c-src(+) in neurons using an affinity-purified anti-peptide antibody, referred to as affi-SB12, that exclusively recognizes this neuron-specific form of the c-src gene product. Using affi-SB12, we examined the distribution of pp60c-src(+) by immunoperoxidase staining of sections through adult rat brains, pp60c-src(+) was widely distributed in rat brain and appeared to be differentially expressed in subpopulations of neurons. The majority of immunoreactive neurons was found in the mesencephalon, cerebellum, pons, and medulla. Telencephalic structures that contained substantial populations of pp60c-src(+)-immunoreactive neurons included layer V of the cerebral cortex and the ventral pallidum. Within individual neurons, pp60c-src(+) immunoreactivity was localized to the cell soma and dendritic processes, while labeling of axons and nerve terminals (puncta) was not as readily detected. Dense accumulations of immunoreactive axons were rare, being most prominent in portions of the inferior and superior olive, and in the spinal trigeminal nucleus. While the regional distribution of pp60c-src(+) immunoreactivity does not correlate with any specific neuronal cell type or first messenger system, this unique pattern of expression of pp60c-src(+) suggests the existence of a previously uncharacterized functional organization within the brain. Furthermore, the localization of this neuron-specific tyrosine kinase in functionally important areas of the nerve cell, namely, dendritic processes, axons, and nerve terminals, suggests that pp60c-src(+) may regulate pleiotropic functions in specific classes of neurons in the adult central nervous system
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A global atmospheric electricity monitoring network for climate and geophysical research
The Global atmospheric Electric Circuit (GEC) is a fundamental coupling network of the climate system connecting electrically disturbed weather regions with fair weather regions across the planet. The GEC sustains the fair weather electric field (or potential gradient, PG) which is present globally and can be measured routinely at the surface using durable instrumentation such as modern electric field mills, which are now widely deployed internationally. In contrast to lightning or magnetic fields, fair weather PG cannot be measured remotely. Despite the existence of many PG datasets (both contemporary and historical), few attempts have been made to coordinate and integrate these fragmented surface measurements within a global framework. Such a synthesis is important elvinin order to fully study major influences on the GEC such as climate variations and space weather effects, as well as more local atmospheric electrical processes such as cloud electrification, lightning initiation, and dust and aerosol charging.
The GloCAEM (Global Coordination of Atmospheric Electricity Measurements) project has brought together experts in atmospheric electricity to make the first steps towards an effective global network for atmospheric electricity monitoring, which will provide data in near real time. Data from all sites are available in identically-formatted files, at both one second and one minute temporal resolution, along with meteorological data (wherever available) for ease of interpretation of electrical measurements. This work describes the details of the GloCAEM database and presents what is likely to be the largest single analysis of PG data performed from multiple datasets at geographically distinct locations. Analysis of the diurnal variation in PG from all 17 GloCAEM sites demonstrates that the majority of sites show two daily maxima, characteristic of local influences on the PG, such as the sunrise effect. Data analysis methods to minimise such effects are presented and recommendations provided on the most suitable GloCAEM sites for the study of various scientific phenomena. The use of the dataset for a further understanding of the GEC is also demonstrated, in particular for more detailed characterization of day-to-day global circuit variability. Such coordinated effort enables deeper insight into PG phenomenology which goes beyond single-location PG measurements, providing a simple measurement of global thunderstorm variability on a day-to-day timescale. The creation of the GloCAEM database is likely to enable much more effective study of atmospheric electricity variables than has ever been possible before, which will improve our understanding of the role of atmospheric electricity in the complex processes underlying weather and climate
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Sunspot observations on 10 and 11 February 1917: a case study in collating known and previously undocumented records
An extensive investigation of ships’ logs, as part of the ‘Old Weather’ citizen-science project,
identified a sunspot observation made from HMS Hilary on 10 February 1917. This sunspot record was accompanied by detailed meteorological records that have enabled a reconstruction of the conditions under which the observation was made (overcast with detached clouds). Although there is no incontrovertible evidence that this was an unaided-eye observation, comparison with an unaided-eye observation recorded on the 11 February 1917 in a local
treatise from Hénán province in China confirms that this sunspot group was visible to the unaided eye. White-light photographs from the Dehra Dun Observatory confirm the detailed description of the sunspot group provided by the naval observer. Moreover, comparisons with tabular data published by the Royal Observatory, Greenwich, confirm the statement that this was an unusually large sunspot group. Indeed, on 11 February 1917 the area of the sunspot group was greater than the area of any sunspot group recorded previously at the Royal Observatory, Greenwich. A comparison with a modern unaided-eye observation confirms that it is possible to observe sunspots under meteorological conditions similar to those experienced on-board HMS Hilary
The behavior of osteoblast-like cells on various substrates with functional blocking of integrin-β1 and integrin-β3
This study was designed to examine the influence of integrin subunit-β1 and subunit-β3 on the behavior of primary osteoblast-like cells, cultured on calcium phosphate (CaP)-coated and non coated titanium (Ti). Osteoblast-like cells were incubated with specific monoclonal antibodies against integrin-β1 and integrin-β3 to block the integrin function. Subsequently, cells were seeded on Ti discs, either non coated or provided with a 2 μm carbonated hydroxyapatite coating using Electrostatic Spray Deposition. Results showed that on CaP coatings, cellular attachment was decreased after a pre-treatment with either anti-integrin-β1 or anti-integrin-β3 antibodies. On Ti, cell adhesion was only slightly affected after a pre-treatment with anti-integrin-β3 antibodies. Scanning electron microscopy showed that on both types of substrate, cellular morphology was not changed after a pre-treatment with either antibody. With quantitative PCR, it was shown for both substrates that mRNA expression of integrin-β1 was increased after a pre-treatment with either anti-integrin-β1 or anti-integrin-β3 antibodies. Furthermore, after a pre-treatment with either antibody, mRNA expression of integrin-β3 and ALP was decreased, on both types of substrate. In conclusion, osteoblast-like cells have the ability to compensate to great extent for the blocking strategy as applied here. Still, integrin-β1 and β3 seem to play different roles in attachment, proliferation, and differentiation of osteoblast-like cells, and responses on CaP-coated substrates differ to non coated Ti. Furthermore, the influence on ALP expression suggests involvement of both integrin subunits in signal transduction for cellular differentiation
Activation of Syk protein tyrosine kinase through interaction with integrin β cytoplasmic domains
AbstractSyk protein tyrosine kinase is essential for immune system development and function [1] and for the maintenance of vascular integrity [2, 3]. In leukocytes, Syk is activated by binding to diphosphorylated immune receptor tyrosine-based activation motifs (pITAMs) [1]. Syk can also be activated by integrin adhesion receptors [4, 5], but the mechanism of its activation is unknown. Here we report a novel mechanism for Syk's recruitment and activation, which requires that Syk bind to the integrin β3 cytoplasmic tail. We found that both Syk and the related kinase ZAP-70 bound the β3 cytoplasmic tail through their tandem SH2 domains. However, unlike Syk binding to pITAMs, this interaction was independent of tyrosine phosphorylation and of the phosphotyrosine binding function of Syk's tandem SH2 domains. Deletion of the four C-terminal residues of the β3 cytoplasmic tail [β3(759X)] decreased Syk binding and disrupted its physical association with integrin αIIbβ3. Furthermore, cells expressing αIIbβ3(759X) failed to exhibit Syk activation or lamellipodia formation upon cell adhesion to the αIIbβ3 ligand, fibrinogen. In contrast, FAK phosphorylation and focal adhesion formation were unimpaired by this mutation. Thus, the direct binding of Syk kinase to the integrin β3 cytoplasmic tail is a novel and functionally significant mechanism for the regulation of this important non-receptor tyrosine kinase
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