173 research outputs found
The role of individual and social variables in task performance.
This paper reports on a data-based study in which we explored - as part of a larger-scale British-Hungarian research project - the effects of a number of affective and social variables on foreign language (L2) learnersâ engagement in oral argumentative tasks. The assumption underlying the investigation was that studentsâ verbal behaviour in oral task situations is partly determined by a number of non-linguistic and non-cognitive factors whose examination may constitute a potentially fruitful extension of existing task-based research paradigms. The independent variables in the study included various aspects of L2 motivation and several factors characterizing the learner groups the participating students were members of (such as group cohesiveness and intermember relations), as well as the learnersâ L2 proficiency and âwillingness to communicateâ in their L1. The dependent variables involved objective measures of the studentsâ language output in two oral argumentative tasks (one in the learnersâ L1, the other in their L2): the quantity of speech and the number of turns produced by the speakers. The results provide insights into the interrelationship of the multiple variables determining the learnersâ task engagement, and suggest a multi-level construct whereby some independent variables only come into force when certain conditions have been met
Infectious Speciation Revisited: Impact of Symbiont-Depletion on Female Fitness and Mating Behavior of Drosophila paulistorum
The neotropical Drosophila paulistorum superspecies, consisting of at least six geographically overlapping but reproductively isolated semispecies, has been the object of extensive research since at least 1955, when it was initially trapped mid-evolution in flagrant statu nascendi. In this classic system females express strong premating isolation patterns against mates belonging to any other semispecies, and yet uncharacterized microbial reproductive tract symbionts were described triggering hybrid inviability and male sterility. Based on theoretical models and limited experimental data, prime candidates fostering symbiont-driven speciation in arthropods are intracellular bacteria belonging to the genus Wolbachia. They are maternally inherited symbionts of many arthropods capable of manipulating host reproductive biology for their own benefits. However, it is an ongoing debate as to whether or not reproductive symbionts are capable of driving host speciation in nature and if so, to what extent. Here we have reevaluated this classic case of infectious speciation by means of present day molecular approaches and artificial symbiont depletion experiments. We have isolated the α-proteobacteria Wolbachia as the maternally transmitted core endosymbionts of all D. paulistorum semispecies that have coevolved towards obligate mutualism with their respective native hosts. In hybrids, however, these mutualists transform into pathogens by overreplication causing embryonic inviability and male sterility. We show that experimental reduction in native Wolbachia titer causes alterations in sex ratio, fecundity, and mate discrimination. Our results indicate that formerly designated Mycoplasma-like organisms are most likely Wolbachia that have evolved by becoming essential mutualistic symbionts in their respective natural hosts; they have the potential to trigger pre- and postmating isolation. Furthermore, in light of our new findings, we revisit the concept of infectious speciation and discuss potential mechanisms that can restrict or promote symbiont-induced speciation at post- and prezygotic levels in nature and under artificial laboratory conditions
Structure of the mirror nuclei Be and B in a microscopic cluster model
The structure of the mirror nuclei Be and B is studied in a
microscopic and three-cluster model
using a fully antisymmetrized 9-nucleon wave function. The two-nucleon
interaction includes central and spin-orbit components and the Coulomb
potential. The ground state of Be is obtained accurately with the
stochastic variational method, while several particle-unbound states of both
Be and B are investigated with the complex scaling method.The
calculation for Be supports the recent identification for the existence of
two broad states around 6.5 MeV, and predicts the and
states at about 4.5 MeV and 8 MeV, respectively. The
similarity of the calculated spectra of Be and B enables one to
identify unknown spins and parities of the B states. Available data on
electromagnetic moments and elastic electron scatterings are reproduced very
well. The enhancement of the 1 transition of the first excited state in
Be is well accounted for. The calculated density of Be is found to
reproduce the reaction cross section on a Carbon target. The analysis of the
beta decay of Li to Be clearly shows that the wave function of Be
must contain a small component that cannot be described by the simple model. This small component can be well accounted for by extending a
configuration space to include the distortion of the -particle to
and partitions.Comment: 24 page
Gamow Shell Model Description of Weakly Bound Nuclei and Unbound Nuclear States
We present the study of weakly bound, neutron-rich nuclei using the nuclear
shell model employing the complex Berggren ensemble representing the bound
single-particle states, unbound Gamow states, and the non-resonant continuum.
In the proposed Gamow Shell Model, the Hamiltonian consists of a one-body
finite depth (Woods-Saxon) potential and a residual two-body interaction. We
discuss the basic ingredients of the Gamow Shell Model. The formalism is
illustrated by calculations involving {\it several} valence neutrons outside
the double-magic core: He and O.Comment: 19 pages, 20 encapsulated PostScript figure
Albumin/asparaginase capsules prepared by ultrasound to retain ammonia
"Published online: 17 June 2016"Asparaginase reduces the levels of asparagine in blood, which is an essential amino acid for the proliferation of lymphoblastic malign cells. Asparaginase converts asparagine into aspartic acid and ammonia. The accumulation of ammonia in the bloodstream leads to hyperammonemia, described as one of the most significant side effects of asparaginase therapy. Therefore, there is a need for asparaginase formulations with the potential to reduce hyperammonemia. We incorporated 2 % of therapeutic enzyme in albumin-based capsules. The presence of asparaginase in the interface of bovine serum albumin (BSA) capsules showed the ability to hydrolyze the asparagine and retain the forming ammonia at the surface of the capsules. The incorporation of Poloxamer 407 in the capsule formulation further increased the ratio aspartic acid/ammonia from 1.92 to 2.46 (and 1.10 from the free enzyme), decreasing the levels of free ammonia. This capacity to retain ammonia can be due to electrostatic interactions and retention of ammonia at the surface of the capsules. The developed BSA/asparaginase capsules did not cause significant cytotoxic effect on mouse leukemic macrophage cell line RAW 264.7. The new BSA/asparaginase capsules could potentially be used in the treatment of acute lymphoblastic leukemia preventing hyperammonemia associated with acute lymphoblastic leukemia (ALL) treatment with asparaginase.Fundação para a CiĂȘncia e a Tecnologia - SFRH\BPD\98388\2013 ; UID/BIO/04469/2013 ; UID/BIA/04050/2013COMPETE 2020 (POCI-01-0145-FEDER-006684
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Leo Strauss and International Relations: The politics of modernity's abyss
This article argues that an engagement with the political philosophy of Leo Strauss is of considerable value in International Relations (IR), in relation to the study of both recent US foreign policy and contemporary IR theory. The question of Straussian activities within and close to the foreign policy-making establishment in the United States during the period leading up to the 2003 invasion of Iraq has been the focus of significant scholarly and popular attention in recent years. This article makes the case that several individuals influenced by Strauss exercised considerable influence in the fields of intelligence production, the media and think tanks, and traces the ways in which elements of Straussâ thought are discernible in their interventions in these spheres. It further argues that Straussâ political philosophy is of broader significance for IR insofar as it can be read as a securitising response to the dangers he associated with the foundationlessness of the modern condition. The article demonstrates that the politics of this response are of crucial importance for contemporary debates between traditional and critical IR theorists
Attentional bias retraining in cigarette smokers attempting smoking cessation (ARTS): study protocol for a double bline randomised controlled trial
YesSmokers attend preferentially to cigarettes and other smoking-related cues in the environment, in what is
known as an attentional bias. There is evidence that attentional bias may contribute to craving and failure to stop smoking.
Attentional retraining procedures have been used in laboratory studies to train smokers to reduce attentional bias, although
these procedures have not been applied in smoking cessation programmes. This trial will examine the efficacy of multiple
sessions of attentional retraining on attentional bias, craving, and abstinence in smokers attempting cessation.
This is a double-blind randomised controlled trial. Adult smokers attending a 7-session weekly stop
smoking clinic will be randomised to either a modified visual probe task with attentional retraining or placebo training.
Training will start 1 week prior to quit day and be given weekly for 5 sessions. Both groups will receive 21 mg transdermal
nicotine patches for 8â12 weeks and withdrawal-orientated behavioural support for 7 sessions. Primary outcome measures
are the change in attentional bias reaction time and urge to smoke on the Mood and Physical Symptoms Scale at 4 weeks
post-quit. Secondary outcome measures include differences in withdrawal, time to first lapse and prolonged abstinence at
4 weeks post-quit, which will be biochemically validated at each clinic visit. Follow-up will take place at 8 weeks, 3 months
and 6 months post-quit.
This is the first randomised controlled trial of attentional retraining in smokers attempting cessation.
This trial could provide proof of principle for a treatment aimed at a fundamental cause of addiction.National Institute for Health Research (NIHR) Doctoral Research Fellowship (DRF) awarded to RB (DRF-2009-02-15
Haslea silbo, a novel cosmopolitan species of blue diatoms
Specimens of a new species of blue diatoms from the genus Haslea Simonsen were discovered in geographically distant sampling sites, first in the Canary Archipelago, then North Carolina, Gulf of Naples, the Croatian South Adriatic Sea, and Turkish coast of the Eastern Mediterranean Sea. An exhaustive characterization of these specimens, using a combined morphological and genomic approach led to the conclusion that they belong to a single new to science cosmopolitan species, Haslea silbo sp. nov. A preliminary characterization of its blue pigment shows similarities to marennine produced by Haslea ostrearia, as evidenced by UVâvisible spectrophotometry and Raman spectrome-try. Life cycle stages including auxosporulation were also observed, providing data on the cardinal points of this species. For the two most geographically distant populations (North Carolina and East Mediterranean), complete mitochondrial and plastid genomes were sequenced. The mitogenomes of both strains share a rare atp6 pseudogene, but the number, nature, and positions of the group II introns inside its cox1 gene differ between the two populations. There are also two pairs of genes fused in single ORFs. The plastid genomes are characterized by large regions of recombination with plasmid DNA, which are in both cases located between the ycf35 and psbA genes, but whose content differs between the strains. The two sequenced strains hosts three plasmids coding for putative serine recombinase protein whose sequences are compared, and four out of six of these plasmids were highly conserved
Neoconservatism as Discourse:Virtue, Power and US Foreign Policy
Neoconservatism in US foreign policy is a hotly contested subject, yet most scholars broadly agree on what it is and where it comes from. From a consensus that it first emerged around the 1960s, these scholars view neoconservatism through what we call the ‘3Ps’ approach, defining it as a particular group of people (‘neocons’), an array of foreign policy preferences and/or an ideological commitment to a set of principles. While descriptively intuitive, this approach reifies neoconservatism in terms of its specific and often static ‘symptoms’ rather than its dynamic constitutions. These reifications may reveal what is emblematic of neoconservatism in its particular historical and political context, but they fail to offer deeper insights into what is constitutive of neoconservatism. Addressing this neglected question, this article dislodges neoconservatism from itsperceived home in the ‘3Ps’ and ontologically redefines it as a discourse. Adopting aFoucauldian approach of archaeological and genealogical discourse analysis, we trace itsdiscursive formations primarily to two powerful and historically enduring discourses ofthe American self — virtue and power — and illustrate how these discourses produce aparticular type of discursive fusion that is ‘neoconservatism’. We argue that to betterappreciate its continued effect on contemporary and future US foreign policy, we needto pay close attention to those seemingly innocuous yet deeply embedded discoursesabout the US and its place in the world, as well as to the people, policies and principlesconventionally associated with neoconservatism
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