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51.
Burguillos MA Deierborg T Kavanagh E Persson A Hajji N Garcia-Quintanilla A Cano J Brundin P Englund E Venero JL Joseph B 《Nature》2011,472(7343):319-324
Activation of microglia and inflammation-mediated neurotoxicity are suggested to play a decisive role in the pathogenesis of several neurodegenerative disorders. Activated microglia release pro-inflammatory factors that may be neurotoxic. Here we show that the orderly activation of caspase-8 and caspase-3/7, known executioners of apoptotic cell death, regulate microglia activation through a protein kinase C (PKC)-δ-dependent pathway. We find that stimulation of microglia with various inflammogens activates caspase-8 and caspase-3/7 in microglia without triggering cell death in vitro and in vivo. Knockdown or chemical inhibition of each of these caspases hindered microglia activation and consequently reduced neurotoxicity. We observe that these caspases are activated in microglia in the ventral mesencephalon of Parkinson's disease (PD) and the frontal cortex of individuals with Alzheimer's disease (AD). Taken together, we show that caspase-8 and caspase-3/7 are involved in regulating microglia activation. We conclude that inhibition of these caspases could be neuroprotective by targeting the microglia rather than the neurons themselves. 相似文献
52.
Like many galaxies of its size, the Milky Way is a disk with prominent spiral arms rooted in a central bar, although our knowledge of its structure and origin is incomplete. Traditional attempts to understand our Galaxy's morphology assume that it has been unperturbed by major external forces. Here we report simulations of the response of the Milky Way to the infall of the Sagittarius dwarf galaxy (Sgr), which results in the formation of spiral arms, influences the central bar and produces a flared outer disk. Two ring-like wrappings emerge towards the Galactic anti-Centre in our model that are reminiscent of the low-latitude arcs observed in the same area of the Milky Way. Previous models have focused on Sgr itself to reproduce the dwarf's orbital history and place associated constraints on the shape of the Milky Way gravitational potential, treating the Sgr impact event as a trivial influence on the Galactic disk. Our results show that the Milky Way's morphology is not purely secular in origin and that low-mass minor mergers predicted to be common throughout the Universe probably have a similarly important role in shaping galactic structure. 相似文献
53.
对松材线虫与其在葡萄牙和欧洲的媒介昆虫樟子松墨天牛(Monochamus galloprovincialis)进行了首次研究。在病死木中发现,松材线虫在天牛刚羽化时聚集在蛹室中,线虫主要集中在天牛的后胸部。天牛羽化后6周内,松材线虫主要在天牛成虫补充营养时进入新寄主树,其次在天牛产卵时也会进入寄主树。总的看来,松材线虫在欧洲与其携带天牛之间互作与其在亚洲与松墨天牛及在北美与卡来罗纳墨天牛之间的关系十分相似。经研究,影响线虫与天牛携带关系的因子有内源和外源两类因子,如化学气味和各种信号。但是,其他多数因子尚未了解。研究影响线虫与天牛携带关系的因子将有助于了解两种生物密切关系的内在机制,并有助于研发出新的防控方法。 相似文献
54.
55.
The development of nineteenth-century geodetic measurement challenges the dominant coherentist account of metric success. Coherentists argue that measurements of a parameter are successful if their numerical outcomes convergence across varying contextual constraints. Aiming at numerical convergence, in turn, offers an operational aim for scientists to solve problems of coordination. Geodesists faced such a problem of coordination between two indicators of the earth's polar flattening, which were both based on imperfect ellipsoid models. While not achieving numerical convergence, their measurements produced novel data that grounded valuable theoretical hypotheses. Consequently, they ought to be regarded as epistemically successful. This insight warrants a dynamic revision of coherentism, which allows to judge the success of a metric based on both its coherence and fruitfulness. On that view, scientific measurement aims to coordinate theoretical definitions and produce novel data and theoretical insights. 相似文献
56.
Machado Claralucia Prates Morandi Maria Isabel Wolf Sellitto Miguel 《Systemic Practice and Action Research》2019,32(6):663-686
Systemic Practice and Action Research - By means of integrated and systemic resilience strategies, it is possible to reduce vulnerability and risk, and at the same time increase the capacity to... 相似文献
57.
María Catalina Ramírez Jaime Plazas Camilo Torres Juan Camilo Silva Luis Camilo Caicedo Miguel Angel González 《Systemic Practice and Action Research》2012,25(2):95-116
In several rural areas in Colombia there is a serious lack of water quality supply. Thereby the problematic situation is understood
as complex one that involves stakeholders with pluralistic interests, multiple variables and requires the development of sustainable
and suitable solutions. In order to address this issue, this paper proposes an integration of engineering design framework
(CDIO) with a systemic approach. Particularly the approach emphasizes on systemic elements such as autonomy, systems within
systems, cooperation between stakeholders and cause effect relations; it also proposes a previous observing phase for engineering
design framework. Thus the proposed systemic framework aims to generate projects that improve living conditions in rural communities
and promote the production of knowledge between the stakeholders to ensure sustainability in the long term. To illustrate
the proposal, this work contains a case study that discusses a project carried out by a research team—Ingenieros Sin Fronteras Colombia—in a rural district near to Colombia’s capital. The experience, which involved and benefited 16 families in the community,
provided strong evidence to support the proposed framework. The paper concludes with a discussion about the replication of
this proposal in other contexts. 相似文献
58.
A synopsis of Pseudoperma is provided. This genus mainly differs from Onocephala and Stethoperma by the antennal tubercles well separated; antennae relatively short, in the female subequal to the body length; and scape and third antennomere subequal in length. Pseudoperma includes two species, P. chalcogramma (Bates, 1887) and P. patruelis (Breuning, 1940), both from Brazil; herein we describe one new species, Pseudoperma lingafelteri sp. nov. from Brazil (Rio de Janeiro). This species differs from its congeners mainly in having the frons and occiput covered with greyish pubescence, and the sides of the elytra with several interrupted or coalescent vittae. We provide new distribution data for Pseudoperma patruelis (Breuning, 1940) from Brazil, Minas Gerais, São Paulo and Santa Catarina, as well as illustrations and a key to the species of Pseudoperma.
http://www.zoobank.org/urn:lsid:zoobank.org:pub:FFD274A3-3AA8-457E-A54C-4CA5AB0340AB 相似文献
59.
Jelena Ćorović Miloš Popović Dan Cogălniceanu Miguel A. Carretero Jelka Crnobrnja-Isailović 《Journal of Natural History》2018,52(29-30):1909-1925
One of the most interesting but elusive members of the European herpetofauna is the meadow lizard (Darevskia praticola). It is a small, ground dwelling, predominantly forest living lacertid, for which many ecological and biological data are still missing. Moreover, at least for the western part of the species range (south-eastern Europe) its distribution and environmental associations are insufficiently known, likely due to difficulties in detection even with intensive field sampling. Here, we complemented the available literature records with our personal observations and explored the effects of environmental factors shaping the species ecological niche and distribution in Europe using the ecological niche modelling approach from Maxent software. The new records of the meadow lizard fill a gap in its known distribution. The most suitable habitats are in central and eastern Serbia, south-western Romania, and central, southern and south-western Bulgaria. Mean temperature of the coldest quarter, vegetation and slope had the strongest effect in defining the meadow lizard’s ecological niche. Niche suitability increased with the increase in forest cover and slope, while the temperature showed a bell-shaped response with a rather narrow tolerance range for temperature. Contrary to expectations, precipitation seemed to have no contribution to the species occurrence. Ecological niche model performance increased with a higher resolution of predictor variables despite the lower number of available occurrence records, although the slope variable had a greater predictive power when calculated at a lower resolution. Interestingly, high resolution vegetation variables (30 m) were able to show some level of habitat fragmentation, which likely resulted from deforestation. Overall, our results epitomize the effects of limited sampling on the biogeography inference of elusive species while having significant repercussions on conservation priorities and management of the species. 相似文献
60.
María Teresa Signes Pont Higinio Mora Mora Gregorio De Miguel Casado David Gil Méndez 《Foundations of Science》2016,21(1):215-223
This paper presents an approach to the belief system based on a computational framework in three levels: first, the logic level with the definition of binary local rules, second, the arithmetic level with the definition of recursive functions and finally the behavioural level with the definition of a recursive construction pattern. Social communication is achieved when different beliefs are expressed, modified, propagated and shared through social nets. This approach is useful to mimic the belief system because the defined functions provide different ways to process the same incoming information as well as a means to propagate it. Our model also provides a means to cross different beliefs so, any incoming information can be processed many times by the same or different functions as it occurs is social nets. 相似文献