Attention-like processes in Drosophila require short-term memory genes     

van Swinderen B 《Science (New York, N.Y.)》2007,315(5818):1590-1593

Although there is much behavioral evidence for complex brain functions in insects, it is not known whether insects have selective attention. In humans, selective attention is a dynamic process restricting perception to a succession of salient stimuli, while less relevant competing stimuli are suppressed. Local field potential recordings in the brains of flies responding to visual novelty revealed attention-like processes with stereotypical temporal properties. These processes were modulated by genes involved in short-term memory formation, namely dunce and rutabaga. Attention defects in these mutants were associated with distinct optomotor effects in behavioral assays.  相似文献   

Applied physics. A critical point for turbulence     

Eckhardt B 《Science (New York, N.Y.)》2011,333(6039):165-166

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Realizing all-spin-based logic operations atom by atom     

Khajetoorians AA  Wiebe J  Chilian B  Wiesendanger R 《Science (New York, N.Y.)》2011,332(6033):1062-1064

An ultimate goal of spintronic research is the realization of concepts for atomic-scale all-spin-based devices. We combined bottom-up atomic fabrication with spin-resolved scanning tunneling microscopy to construct and read out atomic-scale model systems performing logic operations. Our concept uses substrate-mediated indirect exchange coupling to achieve logical interconnection between individual atomic spins. Combined with spin frustration, this concept enables various logical operations between inputs, such as NOT and OR.  相似文献   

Regulators of cerebellar granule cell development act through specific signaling pathways     

Vaudry D  Falluel-Morel A  Leuillet S  Vaudry H  Gonzalez BJ 《Science (New York, N.Y.)》2003,300(5625):1532-1534

The proper development of the central nervous system depends upon a finely tuned balance between cell proliferation and programmed cell death (PCD). Although PCD was initially believed to depend solely on the inability of certain neurons to obtain access to a limited supply of trophic factors, it has become apparent that the local production of death signals is also critical. In this Viewpoint, we discuss several pathways implicated in the survival of cerebellar granule cells- both pathways that protect from apoptosis and pathways that promote apoptosis-and describe how these disparate pathways converge on the final common mediators of PCD. Information on other important pathways implicated in granule cell survival may be found in the Connections Maps.  相似文献   

Sites of neocortical reorganization critical for remote spatial memory     

Maviel T  Durkin TP  Menzaghi F  Bontempi B 《Science (New York, N.Y.)》2004,305(5680):96-99

The hippocampus is crucial for spatial memory formation, yet it does not store long-lasting memories. By combining functional brain imaging and region-specific neuronal inactivation in mice, we identified prefrontal and anterior cingulate cortices as critical for storage and retrieval of remote spatial memories [correction]. Imaging of activity-dependent genes also revealed an involvement of parietal and retrosplenial cortices during consolidation of remote memory. Long-term memory storage within some of these neocortical regions was accompanied by structural changes including synaptogenesis and laminar reorganization, concomitant with a functional disengagement of the hippocampus and posterior cingulate cortex [correction]. Thus, consolidation of spatial memory requires a time-dependent hippocampal-cortical dialogue, ultimately enabling widespread cortical networks to mediate effortful recall and use of cortically stored remote memories independently.  相似文献   

Computation-guided backbone grafting of a discontinuous motif onto a protein scaffold     

Azoitei ML  Correia BE  Ban YE  Carrico C  Kalyuzhniy O  Chen L  Schroeter A  Huang PS  McLellan JS  Kwong PD  Baker D  Strong RK  Schief WR 《Science (New York, N.Y.)》2011,334(6054):373-376

The manipulation of protein backbone structure to control interaction and function is a challenge for protein engineering. We integrated computational design with experimental selection for grafting the backbone and side chains of a two-segment HIV gp120 epitope, targeted by the cross-neutralizing antibody b12, onto an unrelated scaffold protein. The final scaffolds bound b12 with high specificity and with affinity similar to that of gp120, and crystallographic analysis of a scaffold bound to b12 revealed high structural mimicry of the gp120-b12 complex structure. The method can be generalized to design other functional proteins through backbone grafting.  相似文献   

Functional anatomy of the attentional modulation of time estimation     

Coull JT  Vidal F  Nazarian B  Macar F 《Science (New York, N.Y.)》2004,303(5663):1506-1508

Attention modulates our subjective perception of time. The less we attend to an event's duration, the shorter it seems to last. Attention to time or color stimulus attributes was modulated parametrically in an event-related functional magnetic resonance imaging study. Linear increases in task performance were accompanied by corresponding increases in brain activity. Increasing attention to time selectively increased activity in a corticostriatal network, including pre-supplementary motor area and right frontal operculum. Increasing attention to color selectively increased activity in area V4. By identifying areas whose activity was specifically modulated by attention to time, we have defined the core neuroanatomical substrates of timing behavior.  相似文献   

Variable rate nitrogen fertilizer response in wheat using remote sensing     

Bruno Basso  Costanza Fiorentino  Davide Cammarano  Urs Schulthess 《Precision Agriculture》2016,17(2):168-182

Nitrogen (N) fertilizer application can lead to increased crop yields but its use efficiency remains generally low which can cause environmental problems related to nitrate leaching as well as nitrous oxide emissions to the atmosphere. The objectives of this study were to: (i) to demonstrate that properly identified variable rates of N fertilizer lead to higher use efficiency and (ii) to evaluate the capability of high spectral resolution satellite to detect within-field crop N response using vegetation indices. This study evaluated three N fertilizer rates (30, 70, and 90 kg N ha^?1) and their response on durum wheat yield across the field. Fertilizer rates were identified through the adoption of the SALUS crop model, in addition to a spatial and temporal analysis of observed wheat grain yield maps. Hand-held and high spectral resolution satellite remote sensing data were collected before and after a spring side dress fertilizer application with FieldSpec, HandHeld Pro^® and RapidEye?, respectively. Twenty-four vegetation indices were compared to evaluate yield performance. Stable zones within the field were defined by analyzing the spatial stability of crop yield of the previous 5 years (Basso et al. in Eur J Agron 51: 5, 2013). The canopy chlorophyll content index (CCCI) discriminated crop N response with an overall accuracy of 71 %, which allowed assessment of the efficiency of the second N application in a spatial context across each management zone. The CCCI derived from remotely sensed images acquired before and after N fertilization proved useful in understanding the spatial response of crops to N fertilization. Spectral data collected with a handheld radiometer on 100 grid points were used to validate spectral data from remote sensing images in the same locations and to verify the efficacy of the correction algorithms of the raw data. This procedure was presented to demonstrate the accuracy of the satellite data when compared to the handheld data. Variable rate N increased nitrogen use efficiency with differences that can have significant implication to the N₂O emissions, nitrate leaching, and farmer’s profit.  相似文献   

A 5-micron-bright spot on Titan: evidence for surface diversity     

Barnes JW  Brown RH  Turtle EP  McEwen AS  Lorenz RD  Janssen M  Schaller EL  Brown ME  Buratti BJ  Sotin C  Griffith C  Clark R  Perry J  Fussner S  Barbara J  West R  Elachi C  Bouchez AH  Roe HG  Baines KH  Bellucci G  Bibring JP  Capaccioni F  Cerroni P  Combes M  Coradini A  Cruikshank DP  Drossart P  Formisano V  Jaumann R  Langevin Y  Matson DL  McCord TB  Nicholson PD  Sicardy B 《Science (New York, N.Y.)》2005,310(5745):92-95

Observations from the Cassini Visual and Infrared Mapping Spectrometer show an anomalously bright spot on Titan located at 80 degrees W and 20 degrees S. This area is bright in reflected light at all observed wavelengths, but is most noticeable at 5 microns. The spot is associated with a surface albedo feature identified in images taken by the Cassini Imaging Science Subsystem. We discuss various hypotheses about the source of the spot, reaching the conclusion that the spot is probably due to variation in surface composition, perhaps associated with recent geophysical phenomena.  相似文献   

Stocktake study of current fertilisation recommendations across Europe and discussion towards a more harmonised approach     

Suzanne Higgins  Saskia D. Keesstra  Žydrė Kadziuliene  Lionel Jordan-Meille  David Wall  Alessandra Trinchera  Heide Spiegel  Taru Sandén  Andreas Baumgarten  Johannes L. Jensen  Juliane Hirte  Frank Liebisch  Susanne Klages  Philipp Löw  Katrin Kuka  Maarten De Boever  Karoline D'Haene  Sevinc Madenoglu  Hesna Özcan  Wieke Vervuurt  Janjo de Haan  Willem van Geel  Bo Stenberg  Pascal Denoroy  Rok Mihelič  Alar Astover  Raquel Mano  Cristina Sempiterno  Fatima Calouro  Giuseppe Valboa  Helena Aronsson  Tore Krogstad  Stanislav Torma  Jose Gabriel  Peter Laszlo  Nils Borchard  Bartosz Adamczyk  Anna Jacobs  Beata Jurga  Bożena Smreczak  Bruno Huyghebaert  Morgan Abras  Raimonds Kasparinskis  Eloise Mason  Claire Chenu 《European Journal of Soil Science》2023,74(5):e13422

The European Commission has set targets for a reduction in nutrient losses by at least 50% and a reduction in fertiliser use by at least 20% by 2030 while ensuring no deterioration in soil fertility. Within the mandate of the European Joint Programme EJP Soil ‘Towards climate-smart sustainable management of agricultural soils’, the objective of this study was to assess current fertilisation practices across Europe and discuss the potential for harmonisation of fertilisation methodologies as a strategy to reduce nutrient loss and overall fertiliser use. A stocktake study of current methods of delivering fertilisation advice took place across 23 European countries. The stocktake was in the form of a questionnaire, comprising 46 questions. Information was gathered on a large range of factors, including soil analysis methods, along with soil, crop and climatic factors taken into consideration within fertilisation calculations. The questionnaire was completed by experts, who are involved in compiling fertilisation recommendations within their country. Substantial differences exist in the content, format and delivery of fertilisation guidelines across Europe. The barriers, constraints and potential benefits of a harmonised approach to fertilisation across Europe are discussed. The general consensus from all participating countries was that harmonisation of fertilisation guidelines should be increased, but it was unclear in what format this could be achieved. Shared learning in the delivery and format of fertilisation guidelines and mechanisms to adhere to environmental legislation were viewed as being beneficial. However, it would be very difficult, if not impossible, to harmonise all soil test data and fertilisation methodologies at EU level due to diverse soil types and agro-ecosystem influences. Nevertheless, increased future collaboration, especially between neighbouring countries within the same environmental zone, was seen as potentially very beneficial. This study is unique in providing current detail on fertilisation practices across European countries in a side-by-side comparison. The gathered data can provide a baseline for the development of scientifically based EU policy targets for nutrient loss and soil fertility evaluation.  相似文献