Gain control by layer six in cortical circuits of vision

After entering the cerebral cortex, sensory information spreads through six different horizontal neuronal layers that are interconnected by vertical axonal projections. It is believed that through these projections layers can influence each other's response to sensory stimuli, but the specific role that each layer has in cortical processing is still poorly understood. Here we show that layer six in the primary visual cortex of the mouse has a crucial role in controlling the gain of visually evoked activity in neurons of the upper layers without changing their tuning to orientation. This gain modulation results from the coordinated action of layer six intracortical projections to superficial layers and deep projections to the thalamus, with a substantial role of the intracortical circuit. This study establishes layer six as a major mediator of cortical gain modulation and suggests that it could be a node through which convergent inputs from several brain areas can regulate the earliest steps of cortical visual processing.     

Complete genome sequence of Salmonella enterica serovar Typhimurium LT2.

Salmonella enterica subspecies I, serovar Typhimurium (S. typhimurium), is a leading cause of human gastroenteritis, and is used as a mouse model of human typhoid fever. The incidence of non-typhoid salmonellosis is increasing worldwide, causing millions of infections and many deaths in the human population each year. Here we sequenced the 4,857-kilobase (kb) chromosome and 94-kb virulence plasmid of S. typhimurium strain LT2. The distribution of close homologues of S. typhimurium LT2 genes in eight related enterobacteria was determined using previously completed genomes of three related bacteria, sample sequencing of both S. enterica serovar Paratyphi A (S. paratyphi A) and Klebsiella pneumoniae, and hybridization of three unsequenced genomes to a microarray of S. typhimurium LT2 genes. Lateral transfer of genes is frequent, with 11% of the S. typhimurium LT2 genes missing from S. enterica serovar Typhi (S. typhi), and 29% missing from Escherichia coli K12. The 352 gene homologues of S. typhimurium LT2 confined to subspecies I of S. enterica-containing most mammalian and bird pathogens-are useful for studies of epidemiology, host specificity and pathogenesis. Most of these homologues were previously unknown, and 50 may be exported to the periplasm or outer membrane, rendering them accessible as therapeutic or vaccine targets.     

Transiting extrasolar planetary candidates in the Galactic bulge

More than 200 extrasolar planets have been discovered around relatively nearby stars, primarily through the Doppler line shifts owing to reflex motions of their host stars, and more recently through transits of some planets across the faces of the host stars. The detection of planets with the shortest known periods, 1.2-2.5 days, has mainly resulted from transit surveys which have generally targeted stars more massive than 0.75 M(o), where M(o) is the mass of the Sun. Here we report the results from a planetary transit search performed in a rich stellar field towards the Galactic bulge. We discovered 16 candidates with orbital periods between 0.4 and 4.2 days, five of which orbit stars of masses in the range 0.44-0.75 M(o). In two cases, radial-velocity measurements support the planetary nature of the companions. Five candidates have orbital periods below 1.0 day, constituting a new class of ultra-short-period planets, which occur only around stars of less than 0.88 M(o). This indicates that those orbiting very close to more-luminous stars might be evaporatively destroyed or that jovian planets around stars of lower mass might migrate to smaller radii.     

Sequence and analysis of chromosome 5 of the plant Arabidopsis thaliana

The genome of the model plant Arabidopsis thaliana has been sequenced by an international collaboration, The Arabidopsis Genome Initiative. Here we report the complete sequence of chromosome 5. This chromosome is 26 megabases long; it is the second largest Arabidopsis chromosome and represents 21% of the sequenced regions of the genome. The sequence of chromosomes 2 and 4 have been reported previously and that of chromosomes 1 and 3, together with an analysis of the complete genome sequence, are reported in this issue. Analysis of the sequence of chromosome 5 yields further insights into centromere structure and the sequence determinants of heterochromatin condensation. The 5,874 genes encoded on chromosome 5 reveal several new functions in plants, and the patterns of gene organization provide insights into the mechanisms and extent of genome evolution in plants.     

A map of human genome sequence variation containing 1.42 million single nucleotide polymorphisms

We describe a map of 1.42 million single nucleotide polymorphisms (SNPs) distributed throughout the human genome, providing an average density on available sequence of one SNP every 1.9 kilobases. These SNPs were primarily discovered by two projects: The SNP Consortium and the analysis of clone overlaps by the International Human Genome Sequencing Consortium. The map integrates all publicly available SNPs with described genes and other genomic features. We estimate that 60,000 SNPs fall within exon (coding and untranslated regions), and 85% of exons are within 5 kb of the nearest SNP. Nucleotide diversity varies greatly across the genome, in a manner broadly consistent with a standard population genetic model of human history. This high-density SNP map provides a public resource for defining haplotype variation across the genome, and should help to identify biomedically important genes for diagnosis and therapy.     

Systemic View of Interorganisational Relationships: An Analysis of Business Networks

Business networks are formed by organisations with common interests. Inter-firm relations can bring to the companies involved an important contribution in the innovation processes: stimulating the division and sharing of scientific and technical information. This union between companies seems to be an appropriate alternative to promote the organisation's effectiveness. Considering the relevance of inter-organisation networks, their consolidation and the need to understand their essence as a mechanism of competitive advantage, this study is a theoretical reflection on the development of business networks and their proliferation. Using multiple perspectives, the paper discusses the classic authors, as well as contemporary references. It also analyzes the concept of networks and their importance, from a system's perspective.The systemic analysis emphasizes a holistic interpretation, considers the environment, the interdependence of the parts and the business inter-organisation actions. More than a theory, the systemic view can be understood as a model of empirical analysis, used to better understand complex phenomena. Considering inter-organisational relations, the systemic approach consists of the mechanism to understand the dynamics of business networks, their interface, especially considering their role in gaining a competitive advantage. The results discussed in this paper can bring a rich understanding of the role of networks for companies that participate in this initiative.Flávia was sponsored in her Ph.D by CAPES, a Foundation subordinated to the Ministry of Education of Brazil.     

Using Soft Systems Methodology to Fight Against Info-Exclusion: The Experience of a Brazilian University

The aim of this paper is to apply a systemic methodology to analyse the concept of info-inclusion which can guide strategic actions of institutions within civil society and within several levels of government. The paper provides a plan of action that, integrated with other tools, aims at fighting the technological and social gap. We apply Soft System Methodology (SSM), because it provides a holistic approach to info-exclusion. SSM is often used to analyse and resolve problems in complex social studies such as info-exclusion. An info-exclusion reduction project, developed by a university in the country region of Sao Paulo will be provided as a case study. This project is one of the several Brazilian initiatives to solve the problem of limited access to information technology tools. We start by contextualising info-exclusion in Brazil and follow with a review of SSM. We then introduce the concept of info-inclusion and apply SSM to it. We end with a discussion of the results obtained and with some suggestions for action and possible improvements.     

Systemic Model for Diagnosis of the Micro,Small and Medium Enterprises from Two Cities from the Countryside of the State of <Emphasis Type="Italic">São Paulo</Emphasis> in Brazil

This article presents a proposal of a systemic model composed for the micro and small companies (MSE) of the region of Ribeirão Preto and the agents which influenced their environment. The proposed model was based on Stafford Beer’s (Diagnosing the system for organizations. Chichester, Wiley, 1985) systemic methodologies VSM (Viable System Model) and on Werner Ulrich’s (1983) CSH (Critical Systems Heuristics). The VSM is a model for the diagnosis of the structure of an organization and of its flows of information through the application of the cybernetics concepts (Narvarte, In El Modelo del Sistema Viable—MSV: experiencias de su aplicación en Chile. Proyecto Cerebro Colectivo del IAS, Santiago, 2001). On the other hand, CSH focus on the context of the social group applied to the systemic vision as a counterpoint to the organizational management view considered by the VSM. MSE of Ribeirão Preto and Sertãozinho had been analyzed as organizations inserted in systems that relate and integrate with other systems concerning the public administration, entities of representation and promotion agencies. The research questions: which are the bonds of interaction among the subsystems in this process and who are the agents involved? The systemic approach not only diagnosed a social group, formed by MSE of Ribeirão Preto and Sertãozinho, public authorities and support entities, but could also delineate answers that aimed the clarification of obscure questions generating financial assistance to the formularization of efficient actions for the development of this system.     

Negotiation,Management, and Systems Thinking

The mutual apartness of negotiation, management, and systems thinking and practice is highlighted, and a reflection on a systemic view of negotiation is presented. An overview of negotiation studies is given, as well as practical comments on the pursuit of win-win to achieve the general satisfaction of the parties and lasting relationships; the importance of everybody's participation; different views and facets of negotiation and of conflict; the basic variables of power, time, and information; and the basic points for a methodic negotiation process. Some aspects of negotiation have been selected from the management literature. Systems approaches that could contribute to negotiation and benefit from its findings are recalled, integrated into TSI/ LSI, which seems to offer a conceptual and procedural guide to a systemic view of negotiation as a wheel for management, as suggested in the final section.