A possible unifying principle for mechanosensation

Of Aristotle's five senses, we know that sight, smell and much of taste are initiated by ligands binding to G-protein-coupled receptors; however, the mechanical sensations of touch and hearing remain without a clear understanding of their molecular basis. Recently, the relevant force-transducing molecules--the mechanosensitive ion channels--have been identified. Such channel proteins purified from bacteria sense forces from the lipid bilayer in the absence of other proteins. Recent evidence has shown that lipids are also intimately involved in opening and closing the mechanosensitive channels of fungal, plant and animal species.     

A unifying model for the G1 period in prokaryotes and eukaryotes

A model to explain the cell division cycle in both prokaryotes and eukaryotes is presented. No specific 'G1 functions' take place during the G1 period, which is merely part of a larger period for the preparation of DNA synthesis which began at the previous initiation of DNA synthesis. A G1 period exists merely because the doubling time of the cells is greater than the sum of the S and G2 periods.     

一种新型计算机辅助决策系统框架

研究目前常用的基于数据仓库和OLAP的决策支持系统模型 ,提出了在原有系统上结合数据挖掘技术和中间件技术的决策支持系统模型 .该模型增强了数据处理能力 ,同时可以充分利用Intranet/Internet网络的强大优势 .     

A possible terrestrial analogue for haematite concretions on Mars

Recent exploration has revealed extensive geological evidence for a water-rich past in the shallow subsurface of Mars. Images of in situ and loose accumulations of abundant, haematite-rich spherical balls from the Mars Exploration Rover 'Opportunity' landing site at Meridiani Planum bear a striking resemblance to diagenetic (post-depositional), haematite-cemented concretions found in the Jurassic Navajo Sandstone of southern Utah. Here we compare the spherical concretions imaged on Mars to these terrestrial concretions, and investigate the implications for analogous groundwater-related formation mechanisms. The morphology, character and distribution of Navajo haematite concretions allow us to infer host-rock properties and fluid processes necessary for similar features to develop on Mars. We conclude that the formation of such spherical haematite concretions requires the presence of a permeable host rock, groundwater flow and a chemical reaction front.     

A framework for human microbiome research

A variety of microbial communities and their genes (the microbiome) exist throughout the human body, with fundamental roles in human health and disease. The National Institutes of Health (NIH)-funded Human Microbiome Project Consortium has established a population-scale framework to develop metagenomic protocols, resulting in a broad range of quality-controlled resources and data including standardized methods for creating, processing and interpreting distinct types of high-throughput metagenomic data available to the scientific community. Here we present resources from a population of 242 healthy adults sampled at 15 or 18 body sites up to three times, which have generated 5,177 microbial taxonomic profiles from 16S ribosomal RNA genes and over 3.5 terabases of metagenomic sequence so far. In parallel, approximately 800 reference strains isolated from the human body have been sequenced. Collectively, these data represent the largest resource describing the abundance and variety of the human microbiome, while providing a framework for current and future studies.     

A UML profile for framework modeling

The current standard Unified Modeling Language(UML) could not model framework flexibility and extendibility adequately due to lack of appropriate constructs to distinguish framework hot-spots from kernel elements. A new UML profile that may customize UML for framework modeling was presented using the extension mechanisms of UML, providing a group of UML extensions to meet the needs of framework modeling. In this profile, the extended class diagrams and sequence diagrams were defined to straightforwardly identify the hot-spots and describe their instantiation restrictions. A transformation model based on design patterns was also put forward, such that the profile based framework design diagrams could be automatically mapped to the corresponding implementation diagrams. It was proved that the presented profile makes framework modeling more straightforwardly and therefore easier to understand and instantiate.     

Reversal of the net dinitrogen gas flux in coastal marine sediments

The flux of nitrogen from land and atmosphere to estuaries and the coastal ocean has increased substantially in recent decades. The observed increase in nitrogen loading is caused by population growth, urbanization, expanding water and sewer infrastructure, fossil fuel combustion and synthetic fertilizer consumption. Most of the nitrogen is removed by denitrification in the sediments of estuaries and the continental shelf, leading to a reduction in both cultural eutrophication and nitrogen pollution of the open ocean. Nitrogen fixation, however, is thought to be a negligible process in sub-tidal heterotrophic marine systems. Here we report sediment core data from Narragansett Bay, USA, which demonstrate that heterotrophic marine sediments can switch from being a net sink to being a net source of nitrogen. Mesocosm and core incubation experiments, together with a historic data set of mean annual chlorophyll production, support the idea that a climate-induced decrease in primary production has led to a decrease in organic matter deposition to the benthos and the observed reversal of the net sediment nitrogen flux. Our results suggest that some estuaries may no longer remove nitrogen from the water column. Instead, nitrogen could be exported to the continental shelf and the open ocean and could shift the effect of anthropogenic nitrogen loading beyond the immediate coastal zone.     

支持虚拟组织的层次式知识共享框架技术

虚拟组织中协同工作的首要条件是虚拟组织的知识管理和共享.结合了语义网技术,提出了一种基于语义的层次式知识共享框架.该框架使得虚拟组织成员能够共享异构知识、产生创新知识,实现互操作,为组织协同工作奠定基础.同时,其层次结构使得框架具有可扩展和灵活性,从而满足虚拟组织的动态变化需求.     

A New Framework for Focused Web Crawling

Focused crawlers are important tools to support applications such as specialized Web portals, online searching, and Web search engines. A topic driven crawler chooses the best URLs and relevant pages to pursue during Web crawling. It is difficult to deal with irrelevant pages. This paper presents a novel focused crawler framework. In our focused crawler, we propose a method to overcome some of the limitations of dealing with the irrelevant pages. We also introduce the implementation of our focused crawler and present some important metrics and an evaluation function for ranking pages relevance. The experimental result shows that our crawler can obtain more ＂important＂ pages and has a high precision and recall value.     

A multilevel framework for nonlinear surface registration

In this paper, we discuss a new multilevel method for the vascular surface registration. Such registration is used for hemodynamic calculations. Special care is given to the discretization of the distance function and regularizer, as well as to the surface coarsening. We demonstrate the effectiveness of our method of vascular data used in flow computations.     

A framework for interoperability of BPEL-based workflows

With the prevalence of service-oriented architecture (SOA), web services have become the dominating technology to construct workflow systems. As a workflow is the composition of a series of interrelated web services which realize its activities, the interoperability of workflows can be treated as the composition of web services. To address it, a framework for interoperability of business process execution language (BPEL)-based workflows is presented, which can perform three phases, that is, transformation, conformance test and execution. The core components of the framework are proposed, especially how these components promote interoperability. In particular, dynamic binding and re-composition of workflows in terms of web service testing are presented. Besides, an example of business-to-business (B2B) collaboration is provided to illustrate how to perform composition and conformance test.     

通用网格容错框架研究

针对网格计算可靠性需求,提出一套网格计算容错框架,该容错框架包括两个方面：网格错误检测与网格错误处理．本容错框架通过提供一种层次式错误检测方式以及基于策略的通用错误处理方式来保证网格计算的可靠性．错误检测服务按照层次方式组织,最底层是本地错误检测器,它负责收集被检测对象的信息,发送到中间层的数据收集器,中间层数据收集器按照列表方式发送被检测对象的信息到顶层数据收集器．当错误检测器检测到运行错误时,按照决策分析的方法来提供灵活的错误处理方式．对系统的性能评测表明提出的通用网格容错框架具有很好的扩展性、高效性以及较低的额外开销．     

A genetic framework for improving arrhythmia therapy

Abnormalities in heart rhythm continue to cause high rates of illness and death. Better treatment could be provided by solving two main challenges: the early identification of patients who are at risk, and the characterization of molecular pathways that culminate in arrhythmias. By analysing mechanisms that increase susceptibility to arrhythmia in individuals with genetic syndromes, it might be possible to improve current therapies and to develop new ways to treat and prevent common arrhythmias.     

一种元搜索引擎框架模型的设计

元搜索引擎是搜索引擎之上的搜索引擎。用户递交检索请求,元搜索引擎接收该请求后,把它提交给多个预先选定的搜索引擎成员,集中所有的查询结果并以统一的格式返回给用户。首先概述了元搜索引擎的原理和现状,分析了当前研究元搜索引擎的难点所在,并提出改进方案。在此基础上,设计了元搜索引擎的总体框架,提出了查询代理、搜索代理、运算代理三大功能模块,并阐述各代理的功能流程。     

存储特定流数据的通用框架

通过仔细研究存储流数据的各种应用的共同特征,提出了一种数据流存储模型.在数据流存储模型基础上,采用先进的基于组件的开发方法,实现了一个存储流数据的通用框架,通用框架采用本体技术来解决语义互操作性.测试结果表明,通用框架可以调用一组用户提供的过滤算法,筛选出指定数据流中符合条件的信息,将它们成批存储到数据库中.用户可以通过定制和配置参数的方法,在各种不同的应用环境中重用该通用框架.     

A chronological framework for the British Quaternary based on Bithynia opercula

Marine and ice-core records show that the Earth has experienced a succession of glacials and interglacials during the Quaternary (last ～2.6 million years), although it is often difficult to correlate fragmentary terrestrial records with specific cycles. Aminostratigraphy is a method potentially able to link terrestrial sequences to the marine isotope stages (MIS) of the deep-sea record. We have used new methods of extraction and analysis of amino acids, preserved within the calcitic opercula of the freshwater gastropod Bithynia, to provide the most comprehensive data set for the British Pleistocene based on a single dating technique. A total of 470 opercula from 74 sites spanning the entire Quaternary are ranked in order of relative age based on the extent of protein degradation, using aspartic acid/asparagine (Asx), glutamic acid/glutamine (Glx), serine (Ser), alanine (Ala) and valine (Val). This new aminostratigraphy is consistent with the stratigraphical relationships of stratotypes, sites with independent geochronology, biostratigraphy and terrace stratigraphy. The method corroborates the existence of four interglacial stages between the Anglian (MIS 12) and the Holocene in the terrestrial succession. It establishes human occupation of Britain in most interglacial stages after MIS 15, but supports the notion of human absence during the Last Interglacial (MIS 5e). Suspicions that the treeless 'optimum of the Upton Warren interstadial' at Isleworth pre-dates MIS 3 are confirmed. This new aminostratigraphy provides a robust framework against which climatic, biostratigraphical and archaeological models can be tested.     

A dimension reduction framework for understanding cortical maps

We argue that cortical maps, such as those for ocular dominance, orientation and retinotopic position in primary visual cortex, can be understood in terms of dimension-reducing mappings from many-dimensional parameter spaces to the surface of the cortex. The goal of these mappings is to preserve as far as possible neighbourhood relations in parameter space so that local computations in parameter space can be performed locally in the cortex. We have found that, in a simple case, certain self-organizing models generate maps that are near-optimally local, in the sense that they come close to minimizing the neuronal wiring required for local operations. When these self-organizing models are applied to the task of simultaneously mapping retinotopic position and orientation, they produce maps with orientation vortices resembling those produced in primary visual cortex. This approach also yields a new prediction, which is that the mapping of position in visual cortex will be distorted in the orientation fracture zones.