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Three concrete results have been achieved over a 5-year period in Santiago, Chile, in a process addressed to managing through participation the difficult air quality situation of this 5-million-person metropolis: (1) a highly complex problem has become manageable, (2) a legitimate and effective Prevention and Decontamination Plan is in operation, and (3) citizens and the government are mutually committed to this process. This paper describes how these results have been achieved by applying Innovative Development, a social systems methodology developed by the author and co-workers and applied in many fields over the last 20 years. Following a review of the problem and results that have been achieved, an explanation is offered for why a participative methodology is necessary for dealing with a highly complex problem like the current one. The fourth section provides a brief outline of the Innovative Development methodology. The last section presents the case itself, describing three stages. In the short space available we have tried to balance the practical, methodological, and conceptual issues of this case and this approach. 相似文献
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Alfredo Tlahuice-Flores 《自然科学进展(英文版)》2016,26(5):510-515
Most of the studies devoted to thiolated gold clusters suppose that their core and Au-S framework do not suffer from distortion independently of the protecting ligands (-SR) and it is assumed as correct to simplify the ligand as SCH3. In this work is delivered a systematic study of the structure and vibrational properties (IR and Raman) of the Au18(SR)14 cluster. The pursued goal is to understand the dependency of the displayed vibrational properties of the thiolated Au18 cluster with the ligands type. A set of six ligands was considered during calculations of the vibrational properties based on density functional theory (DFT) and in its dispersion-corrected approach (DFT-D). 相似文献
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The pudu (Pudu puda) is a small, endemic deer, and the only native ungulate found in Chilean and Argentinean temperate forests. Its ecology, including its double role as an herbivore and as a prey, is poorly known. Therefore, it is pressing to gain a better understanding of the pudu given that its habitat is being transformed rapidly by anthropogenic causes. On a coastal mountain range in south-central Chile, we conducted a habitat use study and examined the activity patterns of the pudu using camera traps. The study area was a large native forest patch, surrounded by commercial plantations which would not constitute a habitat for this deer. Using a sampling effort of 7559 camera days, we found that this deer was largely nocturnal with little activity during daytime. The pudu selected Araucaria forests, and avoided Nothofagus forests. These behaviours suggest that the pudu traded off habitat use patterns and activity time to avoid predation, mainly by puma which is the top predator in the rich local community of carnivores occurring in the latter habitat. 相似文献
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Unique astrocyte ribbon in adult human brain contains neural stem cells but lacks chain migration 总被引:1,自引:0,他引:1
Sanai N Tramontin AD Quiñones-Hinojosa A Barbaro NM Gupta N Kunwar S Lawton MT McDermott MW Parsa AT Manuel-García Verdugo J Berger MS Alvarez-Buylla A 《Nature》2004,427(6976):740-744
The subventricular zone (SVZ) is a principal source of adult neural stem cells in the rodent brain, generating thousands of olfactory bulb neurons every day. If the adult human brain contains a comparable germinal region, this could have considerable implications for future neuroregenerative therapy. Stem cells have been isolated from the human brain, but the identity, organization and function of adult neural stem cells in the human SVZ are unknown. Here we describe a ribbon of SVZ astrocytes lining the lateral ventricles of the adult human brain that proliferate in vivo and behave as multipotent progenitor cells in vitro. This astrocytic ribbon has not been observed in other vertebrates studied. Unexpectedly, we find no evidence of chains of migrating neuroblasts in the SVZ or in the pathway to the olfactory bulb. Our work identifies SVZ astrocytes as neural stem cells in a niche of unique organization in the adult human brain. 相似文献
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Rafael Andrés Posada-Duque Omar Ramirez Steffen Härtel Nibaldo C. Inestrosa Felipe Bodaleo Christian González-Billault Alfredo Kirkwood Gloria Patricia Cardona-Gómez 《Cellular and molecular life sciences : CMLS》2017,74(1):153-172
CDK5 is a serine/threonine kinase that is involved in the normal function of the adult brain and plays a role in neurotransmission and synaptic plasticity. However, its over-regulation has been associated with Tau hyperphosphorylation and cognitive deficits. Our previous studies have demonstrated that CDK5 targeting using shRNA-miR provides neuroprotection and prevents cognitive deficits. Dendritic spine morphogenesis and forms of long-term synaptic plasticity—such as long-term potentiation (LTP)—have been proposed as essential processes of neuroplasticity. However, whether CDK5 participates in these processes remains controversial and depends on the experimental model. Using wild-type mice that received injections of CDK5 shRNA-miR in CA1 showed an increased LTP and recovered the PPF in deficient LTP of APPswe/PS1Δ9 transgenic mice. On mature hippocampal neurons CDK5, shRNA-miR for 12 days induced increased dendritic protrusion morphogenesis, which was dependent on Rac activity. In addition, silencing of CDK5 increased BDNF expression, temporarily increased phosphorylation of CaMKII, ERK, and CREB; and facilitated calcium signaling in neurites. Together, our data suggest that CDK5 downregulation induces synaptic plasticity in mature neurons involving Ca2+ signaling and BDNF/CREB activation. 相似文献
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Short-lived orogenic cycles and the eclogitization of cold crust by spasmodic hot fluids 总被引:1,自引:0,他引:1
Collision tectonics and the associated transformation of continental crust to high-pressure rocks (eclogites) are generally well-understood processes, but important contradictions remain between tectonothermal models and petrological-isotopic data obtained from such rocks. Here we use 40Ar-39Ar data coupled with a thermal model to constrain the time-integrated duration of an orogenic cycle (the burial and exhumation of a particular segment of the crust) to be less than 13 Myr. We also determine the total duration of associated metamorphic events to be approximately 20 kyr, and of individual heat pulses experienced by the rocks to be as short as 10 years. Such short timescales are indicative of rapid tectonic processes associated with catastrophic deformation events (earthquakes). Such events triggered transient heat advection by hot fluid along deformation (shear) zones, which cut relatively cool and dry subducted crust. In contrast to current thermal models that assume thermal equilibrium and invoke high ambient temperatures in the thickened crust, our non-steady-state cold-crust model satisfactorily explains several otherwise contradictory geological observations. 相似文献
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Alfredo Marcos 《Studies in history and philosophy of science》2004,35(1):73-89
This article seeks to take a step towards recognizing that science can deal with the concrete and individual as well as the universal. I shall concentrate on some of Aristotle’s texts, as there is a long tradition going back to Aristotle, according to which science deals only with the universal, although his work also contains texts of a very different tenor. He tries to improve the process of definition as an attempt to bring science closer to the concrete, but ends up realizing that there are some unreachable limits. There is, however, a second Aristotelian approach to the problem in Metaphysica M 10, a passage which takes scientific rapprochement to the individual further by introducing a distinction between science in potential and science in act. The former is universal, but the latter deals with individual substances and processes. Aristotle himself acknowledges here that in one sense science is universal and in another it is not, a position that raises important ontological and epistemological problems. Some suggestions are also offered concerning the kind of truth applicable to science in act, that is, practical truth. 相似文献
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Genome-wide association study identifies multiple loci influencing human serum metabolite levels 总被引:1,自引:0,他引:1
Kettunen J Tukiainen T Sarin AP Ortega-Alonso A Tikkanen E Lyytikäinen LP Kangas AJ Soininen P Würtz P Silander K Dick DM Rose RJ Savolainen MJ Viikari J Kähönen M Lehtimäki T Pietiläinen KH Inouye M McCarthy MI Jula A Eriksson J Raitakari OT Salomaa V Kaprio J Järvelin MR Peltonen L Perola M Freimer NB Ala-Korpela M Palotie A Ripatti S 《Nature genetics》2012,44(3):269-276
Nuclear magnetic resonance assays allow for measurement of a wide range of metabolic phenotypes. We report here the results of a GWAS on 8,330 Finnish individuals genotyped and imputed at 7.7 million SNPs for a range of 216 serum metabolic phenotypes assessed by NMR of serum samples. We identified significant associations (P < 2.31 × 10(-10)) at 31 loci, including 11 for which there have not been previous reports of associations to a metabolic trait or disorder. Analyses of Finnish twin pairs suggested that the metabolic measures reported here show higher heritability than comparable conventional metabolic phenotypes. In accordance with our expectations, SNPs at the 31 loci associated with individual metabolites account for a greater proportion of the genetic component of trait variance (up to 40%) than is typically observed for conventional serum metabolic phenotypes. The identification of such associations may provide substantial insight into cardiometabolic disorders. 相似文献
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Prickett TD Wei X Cardenas-Navia I Teer JK Lin JC Walia V Gartner J Jiang J Cherukuri PF Molinolo A Davies MA Gershenwald JE Stemke-Hale K Rosenberg SA Margulies EH Samuels Y 《Nature genetics》2011,43(11):1119-1126
G protein-coupled receptors (GPCRs), the largest human gene family, are important regulators of signaling pathways. However, knowledge of their genetic alterations is limited. In this study, we used exon capture and massively parallel sequencing methods to analyze the mutational status of 734 GPCRs in melanoma. This investigation revealed that one family member, GRM3, was frequently mutated and that one of its mutations clustered within one position. Biochemical analysis of GRM3 alterations revealed that mutant GRM3 selectively regulated the phosphorylation of MEK, leading to increased anchorage-independent growth and migration. Melanoma cells expressing mutant GRM3 had reduced cell growth and cellular migration after short hairpin RNA-mediated knockdown of GRM3 or treatment with a selective MEK inhibitor, AZD-6244, which is currently being used in phase 2 clinical trials. Our study yields the most comprehensive map of genetic alterations in the GPCR gene family. 相似文献