Why fisheries collapse and what to do about it.

With the collapse of fisheries in many parts of the world causing widespread economic harm, attention is focused on a possible cause and remedy of fishery collapse. Economic theory for managing a renewable resource, such as a fishery, leads to an ecologically unstable equilibrium as difficult to maintain as balancing a marble on top of a dome. A fishery should be managed for ecological stability instead--in the analogy, as easy to maintain as keeping a marble near the base of a bowl. The goal of ecological stability is achieved if the target stock is above that producing maximum sustainable yield and harvested at less than the maximum sustainable yield. The cost of managing for ecological stability, termed "natural insurance," is low if the fishery is sufficiently productive. This cost is shown to pay for itself over the long term in a variable and uncertain environment. An ecologically stable target stock may be attained either with annually variable quotas following current practice or, preferably, through a market mechanism whereby fish are taxed at dockside if caught when the stock was below target and are untaxed otherwise. In this regulatory environment, the goal of maximizing short-term revenue coincides with the goal of ecological stability, thereby also maximizing long-term revenue. This new approach to fishery management is illustrated with the recently collapsed Newfoundland fishing industry. The Newfoundland cod fishery is expected to rebuild to an ecologically stable level in about 9 years and thereafter support an annual harvest of about 75% of the 1981-1990 average.

Swiveling-domain mechanism for enzymatic phosphotransfer between remote reaction sites.

The crystal structure of pyruvate phosphate dikinase, a histidyl multiphosphotransfer enzyme that synthesizes adenosine triphosphate, reveals a three-domain molecule in which the phosphohistidine domain is flanked by the nucleotide and the phosphoenolpyruvate/pyruvate domains, with the two substrate binding sites approximately 45 angstroms apart. The modes of substrate binding have been deduced by analogy to D-Ala-D-Ala ligase and to pyruvate kinase. Coupling between the two remote active sites is facilitated by two conformational states of the phosphohistidine domain. While the crystal structure represents the state of interaction with the nucleotide, the second state is achieved by swiveling around two flexible peptide linkers. This dramatic conformational transition brings the phosphocarrier residue in close proximity to phosphoenolpyruvate/pyruvate. The swiveling-domain paradigm provides an effective mechanism for communication in complex multidomain/multiactive site proteins.

Hypothesis: "Rogue cell"-type chromosomal damage in lymphocytes is associated with infection with the JC human polyoma virus and has implications for oncopenesis.

The hemagglutination inhibition antibody titers against the JC and BK polyoma viruses (JCV and BKV, respectively) are significantly elevated in individuals exhibiting "rogue" cells among their cultured lymphocytes. However, the elevation is so much greater with respect to JCV that the BKV elevation could readily be explained by cross reactivity to the capsid protein of these two closely related viruses. The JCV exhibits high sequence homology with the simian papovavirus, simian virus 40 (SV40), and inoculation of human fetal brain cells with JCV produces polyploidy and chromosomal damage very similar to that produced by SV40. We suggest, by analogy with the effects of SV40, that these changes are due to the action of the viral large tumor antigen, a pluripotent DNA binding protein that acts in both transcription and replication. The implications of these findings for oncogenesis are briefly discussed.

Mutants in the Exo I motif of Escherichia coli dnaQ: defective proofreading and inviability due to error catastrophe.

The Escherichia coli dnaQ gene encodes the proofreading 3' exonuclease (epsilon subunit) of DNA polymerase III holoenzyme and is a critical determinant of chromosomal replication fidelity. We constructed by site-specific mutagenesis a mutant, dnaQ926, by changing two conserved amino acid residues (Asp-12-->Ala and Glu-14-->Ala) in the Exo I motif, which, by analogy to other proofreading exonucleases, is essential for the catalytic activity. When residing on a plasmid, dnaQ926 confers a strong, dominant mutator phenotype, suggesting that the protein, although deficient in exonuclease activity, still binds to the polymerase subunit (alpha subunit or dnaE gene product). When dnaQ926 was transferred to the chromosome, replacing the wild-type gene, the cells became inviable. However, viable dnaQ926 strains could be obtained if they contained one of the dnaE alleles previously characterized in our laboratory as antimutator alleles or if it carried a multicopy plasmid containing the E. coli mutL+ gene. These results suggest that loss of proofreading exonuclease activity in dnaQ926 is lethal due to excessive error rates (error catastrophe). Error catastrophe results from both the loss of proofreading and the subsequent saturation of DNA mismatch repair. The probability of lethality by excessive mutation is supported by calculations estimating the number of inactivating mutations in essential genes per chromosome replication.

Postseptational chromosome partitioning in bacteria.

Mutations in the spoIIIE gene prevent proper partitioning of one chromosome into the developing prespore during sporulation but have no overt effect on partitioning in vegetatively dividing cells. However, the expression of spoIIIE in vegetative cells and the occurrence of genes closely related to spoIIIE in a range of nonsporulating eubacteria suggested a more general function for the protein. Here we show that SpoIIIE protein is needed for optimal chromosome partitioning in vegetative cells of Bacillus subtilis when the normal tight coordination between septation and nucleoid partitioning is perturbed or when septum positioning is altered. A functional SpoIIIE protein allows cells to recover from a state in which their chromosome has been trapped by a closing septum. By analogy to its function during sporulation, we suggest that SpoIIIE facilitates partitioning by actively translocating the chromosome out of the septum. In addition to enhancing the fidelity of nucleoid partitioning, SpoIIIE also seems to be required for maximal resistance to antibiotics that interfere with DNA metabolism. The results have important implications for our understanding of the functions of genes involved in the primary partitioning machinery in bacteria and of how septum placement is controlled.

O \"si\" da técnica psicanalítica: uma análise institucional do discurso de O mal-estar na civilização

Partindo das considerações de que os termos sujeito e subjetividade permeiam o discurso psicanalítico contemporâneo e de que são, direta e indiretamente, atribuídos a Freud a despeito de ele próprio nunca tê-los conceituado, esta pesquisa tem como objetivo caracterizar um perfil de sujeito a partir do discurso freudiano. O trabalho orientou-se pela metodologia da Análise Institucional do Discurso, uma analítica do domínio subjetivo que toma o discurso em seu caráter de ato e acontecimento. Primeiramente se realizou um estudo de As técnicas de si, de Michel Foucault, de modo a permitir o circunstanciamento da psicanálise como uma técnica que produz um si, um sujeito este circunstanciamento permitiu, então, tomar sujeito e subjetividade na qualidade de produções histórica, geográfica e analiticamente contextualizadas, não como formas de imanência ou transcendência. A partir desse pressuposto, elaborou-se uma análise institucional do discurso de O mal-estar na civilização que privilegiou não apenas seu conteúdo, mas principalmente seu modo de produção, colocando em relevo o contexto presente no texto, as interlocuções que se criam, os lugares atribuídos e ocupados, as expectativas assim mobilizadas, as estratégias discursivas utilizadas, os jogos de poder e verdade exercidos, bem como os efeitos de reconhecimento e desconhecimento então facultados. Esta análise mostrou que Freud exerce uma perspectiva de interioridade, pois o mal-estar que acomete a civilização é compreendido em analogia à concepção psicanalítica de desenvolvimento individual, explicando, em suma, a cultura pelo prisma do indivíduo; evidenciou que as teorizações sobre a vida instintiva são a principal sustentação do discurso sobre o mal-estar da civilização; apontou como as estratégias discursivas utilizadas por Freud promovem a subjetivação, por parte do leitor, daquilo que seu discurso produz como verdade; e que o conceito de indivíduo é ocasião de exercício daquela perspectiva de interioridade e de atualização dos pressupostos teóricos. Com base nisso, pôde-se caracterizar um sujeito universal; psicologizado; determinado sobretudo pelos movimentos da sexualidade e da agressividade; cuja tônica recai sobre o dito mundo interno; dotado de origens e propósitos concernentes à vida instintiva; e cujo perfil é delimitado pela tarefa de administração dos instintos, isto é, cujo perfil se dá entre os imperativos superegóicos de renúncia e a margem de liberdade de que dispõe para satisfazer as exigências do princípio de prazer. Observou-se também, na esteira do pontuado por Guirado (2010), que em geral Freud naturaliza os termos do discurso teórico, fazendo de sua universalização a condição e o limite para se pensar o domínio subjetivo e a singularidade; diferentemente de Foucault, que compreende esse domínio em referência às relações de poder e saber, de forma contextualizada. Do ponto de vista da análise institucional do discurso freudiano, concluiu-se, finalmente, que o si ao qual a técnica psicanalítica dá lastro é efeito da perspectiva exercida por Freud, que promove o reconhecimento da interioridade instintiva como crivo da civilização, de um modo de vida e de si mesmo

Excitations in Bose-Einstein condensates: collective modes, quantum turbulence and matter wave statistics

In this thesis, we present the generation and studies of a 87Rb Bose-Einstein condensate (BEC) perturbed by an oscillatory excitation. The atoms are trapped in a harmonic magnetic trap where, after an evaporative cooling process, we produce the BEC. In order to study the effect caused by oscillatory excitations, a quadrupole magnetic field time oscillatory is superimposed to the trapping potential. Through this perturbation, collective modes were observed. The dipole mode is excited even for low excitation amplitudes. However, a minimum excitation energy is needed to excite the condensate quadrupole mode. Observing the excited cloud in TOF expansion, we note that for excitation amplitude in which the quadrupole mode is excited, the cloud expands without invert its aspect ratio. By looking these clouds, after long time-of-flight, it was possible to see vortices and, sometimes, a turbulent state in the condensed cloud. We calculated the momentum distribution of the perturbed BECs and a power law behavior, like the law to Kolmogorov turbulence, was observed. Furthermore, we show that using the method that we have developed to calculate the momentum distribution, the distribution curve (including the power law exponent) exhibits a dependence on the quadrupole mode oscillation of the cloud. The randomness distribution of peaks and depletions in density distribution image of an expanded turbulent BEC, remind us to the intensity profile of a speckle light beam. The analogy between matter-wave speckle and light speckle is justified by showing the similarities in the spatial propagation (or time expansion) of the waves. In addition, the second order correlation function is evaluated and the same dependence with distance was observed for the both waves. This creates the possibility to understand the properties of quantum matter in a disordered state. The propagation of a three-dimensional speckle field (as the matter-wave speckle described here) creates an opportunity to investigate the speckle phenomenon existing in dimensions higher than 2D (the case of light speckle).

Nitrogen regulation of protein–protein interactions and transcript levels of GlnK PII regulator and AmtB ammonium transporter homologs in Archaea

Gene homologs of GlnK PII regulators and AmtB-type ammonium transporters are often paired on prokaryotic genomes, suggesting these proteins share an ancient functional relationship. Here, we demonstrate for the first time in Archaea that GlnK associates with AmtB in membrane fractions after ammonium shock, thus, providing a further insight into GlnK-AmtB as an ancient nitrogen sensor pair. For this work, Haloferax mediterranei was advanced for study through the generation of a pyrE2-based counterselection system that was used for targeted gene deletion and expression of Flag-tagged proteins from their native promoters. AmtB1-Flag was detected in membrane fractions of cells grown on nitrate and was found to coimmunoprecipitate with GlnK after ammonium shock. Thus, in analogy to bacteria, the archaeal GlnK PII may block the AmtB1 ammonium transporter under nitrogen-rich conditions. In addition to this regulated protein–protein interaction, the archaeal amtB-glnK gene pairs were found to be highly regulated by nitrogen availability with transcript levels high under conditions of nitrogen limitation and low during nitrogen excess. While transcript levels of glnK-amtB are similarly regulated by nitrogen availability in bacteria, transcriptional regulators of the bacterial glnK promoter including activation by the two-component signal transduction proteins NtrC (GlnG, NRI) and NtrB (GlnL, NRII) and sigma factor σN (σ54) are not conserved in archaea suggesting a novel mechanism of transcriptional control.

Myth, Language, and Complex Ideologies

Ideologies use for their conservation and propagation persuasive methods of communication: rhetoric. Rhetoric is analyzed from the semiotic and logical-mathematical points of view. The following hypotheses are established: (1) language L is a self-explanatory system, mediated by a successive series of systems of cultural conventions, (2) connotative significances of an ideological advertising rhetoric must be known, and (3) the notion of ideological information is a neutral notion that does not imply the valuation of ideology or its conditions of veracity or falsification. Rhetorical figures like metonymy, metaphor, parable analogy, and allegory are defined as relations. Metaphor and parable are order relations. Operations of metonymic and metaphoric substitution are defined and several theorems derived from these operations have been deduced.

Reality, Systems and Impure Systems

Impure systems contain Objects and Subjects: Subjects are human beings. We can distinguish a person as an observer (subjectively outside the system) and that by definition is the Subject himself, and part of the system. In this case he acquires the category of object. Objects (relative beings) are significances, which are the consequence of perceptual beliefs on the part of the Subject about material or energetic objects (absolute beings) with certain characteristics.The IS (Impure System) approach is as follows: Objects are perceptual significances (relative beings) of material or energetic objects (absolute beings). The set of these objects will form an impure set of the first order. The existing relations between these relative objects will be of two classes: transactions of matter and/or energy and inferential relations. Transactions can have alethic modality: necessity, possibility, impossibility and contingency. Ontic existence of possibility entails that inferential relations have Deontic modality: obligation, permission, prohibition, faculty and analogy. We distinguished between theorems (natural laws) and norms (ethical, legislative and customary rules of conduct).

A new boundary-based morphological model

Mathematical morphology addresses the problem of describing shapes in an n-dimensional space using the concepts of set theory. A series of standardized morphological operations are defined, and they are applied to the shapes to transform them using another shape called the structuring element. In an industrial environment, the process of manufacturing a piece is based on the manipulation of a primitive object via contact with a tool that transforms the object progressively to obtain the desired design. The analogy with the morphological operation of erosion is obvious. Nevertheless, few references about the relation between the morphological operations and the process of design and manufacturing can be found. The non-deterministic nature of classic mathematical morphology makes it very difficult to adapt their basic operations to the dynamics of concepts such as the ordered trajectory. A new geometric model is presented, inspired by the classic morphological paradigm, which can define objects and apply morphological operations that transform these objects. The model specializes in classic morphological operations, providing them with the determinism inherent in dynamic processes that require an order of application, as is the case for designing and manufacturing objects in professional computer-aided design and manufacturing (CAD/CAM) environments. The operators are boundary-based so that only the points in the frontier are handled. As a consequence, the process is more efficient and more suitable for use in CAD/CAM systems.

Structural Characterization of Micro- and Mesoporous Carbon Materials Using In Situ High Pressure 129Xe NMR Spectroscopy

In situ high pressure 129Xe NMR spectroscopy in combination with volumetric adsorption measurements were used for the textural characterization of different carbon materials with well-defined porosity including microporous carbide-derived carbons, ordered mesoporous carbide-derived carbon, and ordered mesoporous CMK-3. Adsorption/desorption isotherms were measured also by NMR up to relative pressures close to p/p0 = 1 at 237 K. The 129Xe NMR chemical shift of xenon adsorbed in porous carbons is found to be correlated with the pore size in analogy to other materials such as zeolites. In addition, these measurements were performed loading the samples with n-nonane. Nonane molecules preferentially block the micropores. However, 129Xe NMR spectroscopy proves that the nonane also influences the mesopores, thus providing information about the pore system in hierarchically structured materials.

Ciberperiodismo: definiciones, desarrollo y tipología

La aparición de Internet ha cambiado los medios de comunicación. En un primer momento, el desconocimiento de las posibilidades que ofrecía marcaron el paso del mundo analógico al mundo digital, pero después los diarios, las radios y las televisiones se han introducido masivamente en la Red y también han aparecido nuevos medios creados específicamente para Internet. Estos cambios han sido objeto de estudio de los investigadores y se ha hecho necesaria la consolidación de una nueva terminología. Se explican en este trabajo las cuestiones terminológicas que afectan el ciberperiodismo, se define el concepto de estudio, para hacer después un breve recorrido por la historia de la ciberprensa y las diferentes etapas y tipologías de cibermedios que han establecido los investigadores.

Enlaces. Relatos sobre la conexión de tiempos y lugares

A través de algunos relatos en torno al espacio se ensaya un discurso sobre la conexión entre arte y vida, que postula la relación entre escenas, la continuidad entre arte y lugar, y el entrelazamiento creativo y narrativo entre disciplinas artísticas. El artículo pretende registrar la conexión, en ambos sentidos del vector, entre lugares y proyectos, un vínculo inasible pero real. Todo escritor persigue las marcas de la actividad humana sobre los objetos, la probatura de una teoría de los objetos inanimados que registramos desde nuestras herramientas de analogía y contraste antropométrico. Ése es también el empeño del arte y ésa era la definición del propio origen de la pintura de Plinio, el intento de retener la compañía de la persona amada dibujando la sombra de su perfil sobre una superficie, convertida en un museo espontáneo al fresco. Las obras de arte, como algunos proyectos, deberían ser hilos, en el tiempo y el espacio, enlaces del arte y la vida: entre nuestra mesa y el territorio, entre la mente y la materia, entre el hombre y el mundo.

Commonplace book of John Bullard, 1775-1779

This bound volume contains excerpts copied by Jonathan Bullard from books he read as a student at Harvard in the mid 1770s. Excerpts include an unattributed poem titled "On Friendship," which appeared in the "poetical essays" section of Volume 36 of the London Magazine in 1767; Joseph Butler, The Analogy of Religion, 1736; The Quaker's Grace; a history of England; Newton's laws; Plutarch's Morals; Benjamin Franklin's writings on the Aurora Borealis. The volume also includes several extracts from articles about the death of John Paddock (Class of 1776), who drowned in the Charles in the summer of 1773, sheet music for two songs, "The Rapture," and "A Song" from Henry Harington's "Damon and Chlora," and a transcription of the satirical "Book of Harvard," written in response to the Butter Rebellion of 1766. Interleaved in the middle of the volume is a transcription from an ecclesiastical event moderated by Ebenezer Bridge in Medford, Mass. on November 20, 1779. The variety of texts suggests the commonplace book was not used solely for academic works.