431 research outputs found
Morphometric differences in the grasshopper Cornops aquaticum (Bruner, 1906) from South America and South Africa
The semi-aquatic grasshopper Cornops aquaticum is native to South America and inhabits lowlands from southern Mexico to Central Argentina and Uruguay. It is host-specific to aquatic plants in the genera Eichhornia and Pontederia. A quarantine population has existed in South Africa for 10 y, and it is planned to release it there as a biological control agent of water hyacinth, E. crassipes. Various studies of C. aquaticum are coordinated under HICWA (www.mpil-ploen.mpg.de). This paper compares the morphometry of the release population and 11 native populations in South America. We tested four hypotheses: 1) South African and South American populations of C. aquaticum differ in morphology; 2) the South African laboratory population is more similar to other isolated populations in South America than to nonisolated populations; 3) morphology differs across sites; 4) morphology differs with host plant. South African populations differed from continental nonisolated populations, but not from continental isolated ones. Isolated populations presented smaller individuals than nonisolated, but there was also a change in male morphology: while in nonisolated populations male wing length was similar to their body length, in isolated populations, male wings were smaller than body length. Females were larger when on Eicchornia azurea than on E. crassipes, while males presented larger wings than their body on E. azurea, and similar lengths on E. crassipes. These morphological changes may have resulted from phenotypic plasticity, selection for small size, or because of a loss of genetic diversity in quantitative traits.Fil: Adis, Joachim. Institute for Limnology; AlemaniaFil: Sperber, Carlos F. Universidade Federal de Viçosa; BrasilFil: Brede, Edward G. Institute for Limnology; AlemaniaFil: Capello, Soledad. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Santa Fe. Instituto Nacional de LimnologĂa. Universidad Nacional del Litoral. Instituto Nacional de LimnologĂa; ArgentinaFil: Franceschini, Maria Celeste. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Nordeste. Centro de EcologĂa Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de EcologĂa Aplicada del Litoral; ArgentinaFil: Hill, Martin. Rhodes University; SudĂĄfricaFil: Lhano, Marcos G. Universidade Federal de Viçosa; BrasilFil: Marques, MarinĂȘ. A;z M.. Universidade Federal de Mato Grosso; BrasilFil: Nunes, Ana L.. MusĂ©u Paraense EmĂlio Goeldi; BrasilFil: Polar, Perry. CAB International; Trinidad y Tobag
Barriers and facilitators to providing CBT for people living with dementia: perceptions of psychological therapists
Many people living with dementia or mild cognitive impairment (MCI) experience anxiety and depression. Cognitive behavioral therapy (CBT) is a recommended treatment for adults, commonly provided through primary care psychological therapies services. This study explored the facilitators and barriers to providing CBT interventions for people living with dementia or MCI, as perceived by therapists working in such services. Structured interviews were conducted with fourteen clinicians recruited through primary care psychological therapies services about their experiences of working with people living with dementia or MCI and their ideas about factors that enhance or hinder offering and delivering CBT to this population. Interview recordings were transcribed and analyzed using Thematic Analysis. Credibility checks were incorporated throughout. Three themes were identified: 'attitudes towards dementia', 'competing demands', and 'pressure without support'. Perceived facilitators and barriers occurred across individual, service, and system levels. Facilitators were: positive engagement and outcomes for people living with dementia or MCI, positive attitudes of clinicians, and flexibility within some services. In contrast, perceived barriers were: stigma towards dementia and mental health in older adults, high pressure on staff to perform with a lack of support to do so, exclusion based on diagnosis, and inflexibility within some services. Clinicians were confident that people living with dementia or MCI could benefit from CBT, with some adaptations to delivery. There are implications for staff support and training, and for commissioning practices relating to the tension between minimal resources, equitable access, and person-centered care
Green Up-Conversion Laser-Emission In Er-Doped Crystals At Room-Temperature
We report room-temperature pulsed up-conversion laser oscillation in Er-doped LiYF4 and KYF4 at 551 and 562 nm, respectively. In both crystals laser oscillation is observed on the S-4(3/2)-I-4(15/2) ground state transition. Excitation was provided by a tunable flashlamp-pumped Ti:sapphire laser in the spectral region around 810 nm. Additional pumping with a continuous wave krypton ion laser at 647 nm was beneficial to both lasers. Laser action has also been observed in Er-doped Y3Al5O12 on the same transition
Behavioural activation for depression in older people: systematic review and meta-analysis
BACKGROUND: Behavioural activation is an effective treatment for depression in the general adult population but it is unclear whether it is effective for older people. AIMS: To systematically review randomised controlled trials (RCTs) of behavioural activation for depression in older people. METHOD: We searched Medline, EMBASE, PsycINFO, CINAHL and online trial registers for RCTs of behavioural activation for depression in older people. RESULTS: Eighteen trials were included in the meta-analyses. Behavioural activation reduced mean depression scores for older people living in the community as a stand-alone treatment: standardised mean difference (SMD) -0.72, 95% CI -1.04 to -0.41. It was also effective as part of a multicomponent intervention (SMD -0.44, 95% CI -0.56 to -0.32). CONCLUSIONS: Behavioural activation significantly reduces depressive symptoms in older people in the community; however, given that most studies are small and with significant bias results should be interpreted with caution. Further high-quality trials of behavioural activation for this age group are needed
Comparative genomics of Enterococcus faecalis from healthy Norwegian infants
<p>Abstract</p> <p>Background</p> <p><it>Enterococcus faecalis</it>, traditionally considered a harmless commensal of the intestinal tract, is now ranked among the leading causes of nosocomial infections. In an attempt to gain insight into the genetic make-up of commensal <it>E. faecalis</it>, we have studied genomic variation in a collection of community-derived <it>E. faecalis </it>isolated from the feces of Norwegian infants.</p> <p>Results</p> <p>The <it>E. faecalis </it>isolates were first sequence typed by multilocus sequence typing (MLST) and characterized with respect to antibiotic resistance and properties associated with virulence. A subset of the isolates was compared to the vancomycin resistant strain <it>E. faecalis </it>V583 (V583) by whole genome microarray comparison (comparative genomic hybridization (CGH)). Several of the putative enterococcal virulence factors were found to be highly prevalent among the commensal baby isolates. The genomic variation as observed by CGH was less between isolates displaying the same MLST sequence type than between isolates belonging to different evolutionary lineages.</p> <p>Conclusion</p> <p>The variations in gene content observed among the investigated commensal <it>E. faecalis </it>is comparable to the genetic variation previously reported among strains of various origins thought to be representative of the major <it>E. faecalis </it>lineages. Previous MLST analysis of <it>E. faecalis </it>have identified so-called high-risk enterococcal clonal complexes (HiRECC), defined as genetically distinct subpopulations, epidemiologically associated with enterococcal infections. The observed correlation between CGH and MLST presented here, may offer a method for the identification of lineage-specific genes, and may therefore add clues on how to distinguish pathogenic from commensal <it>E. faecalis</it>. In this work, information on the core genome of <it>E. faecalis </it>is also substantially extended.</p
Spectroscopy And Green Up-Conversion Laser-Emission Of Er(3+)-Doped Crystals At Room-Temperature
The spectroscopic parameters of Er3+-doped crystals were determined with regard to the upconversion laser parameters of the green transition S-4(3/2) -- \u3e I-4(15/2), The influence of excited-state absorption on this laser channel was determined. Furthermore, upconversion pump mechanisms using ground-state and excited-state absorption around 810 and 970 nm were investigated by direct measurements of excited-state absorption. The spectroscopic results confirm the pulsed room-temperature laser experiments on the S-4(3/2) -- \u3e I-5(5/2) transition. The lasers based on Er:LiYF4, Er:Y3Al5O12, and Er:Lu3Al5O12 were directly excited into the upper laser level by an excimer laser pumped dye laser in the blue spectral range. In Er:LiYF4, Er:KYF4, and Er:Y3Al5O12, laser action was achieved with two-step upconversion pumping by a Ti:sapphire laser and a krypton ion laser. In the case of the fluorides, the additional pumping with the krypton ion laser was not necessary. The laser emission wavelengths were 551 nm for Er:LiYF4, 561 nm for Er:Y3Al5012 and Er:Lu3Al5O12, and 562 nm for Er:KYF4. In addition, green quasi-cw laser emission of Er:LiYF4 pumped with an argon-ion laser was realized at room temperature
Optimal interdependence between networks for the evolution of cooperation
Recent research has identified interactions between networks as crucial for the outcome of evolutionary
games taking place on them. While the consensus is that interdependence does promote cooperation by
means of organizational complexity and enhanced reciprocity that is out of reach on isolated networks, we
here address the question just how much interdependence there should be. Intuitively, one might assume
the more the better. However, we show that in fact only an intermediate density of sufficiently strong
interactions between networks warrants an optimal resolution of social dilemmas. This is due to an intricate
interplay between the heterogeneity that causes an asymmetric strategy flow because of the additional links
between the networks, and the independent formation of cooperative patterns on each individual network.
Presented results are robust to variations of the strategy updating rule, the topology of interdependent
networks, and the governing social dilemma, thus suggesting a high degree of universality
Magnetoresistance through a single molecule
The use of single molecules to design electronic devices is an extremely
challenging and fundamentally different approach to further downsizing
electronic circuits. Two-terminal molecular devices such as diodes were first
predicted [1] and, more recently, measured experimentally [2]. The addition of
a gate then enabled the study of molecular transistors [3-5]. In general terms,
in order to increase data processing capabilities, one may not only consider
the electron's charge but also its spin [6,7]. This concept has been pioneered
in giant magnetoresistance (GMR) junctions that consist of thin metallic films
[8,9]. Spin transport across molecules, i.e. Molecular Spintronics remains,
however, a challenging endeavor. As an important first step in this field, we
have performed an experimental and theoretical study on spin transport across a
molecular GMR junction consisting of two ferromagnetic electrodes bridged by a
single hydrogen phthalocyanine (H2Pc) molecule. We observe that even though
H2Pc in itself is nonmagnetic, incorporating it into a molecular junction can
enhance the magnetoresistance by one order of magnitude to 52%.Comment: To appear in Nature Nanotechnology. Present version is the first
submission to Nature Nanotechnology, from May 18th, 201
Development of structural correlations and synchronization from adaptive rewiring in networks of Kuramoto oscillators
L.P. acknowledges support from the National Science Foundation Graduate Research Fellowship Program. J.K. acknowledges support from the National Science Foundation Graduate Research Fellowship Program and NIH T32-EB020087, PD: Felix W. Wehrli. D.S.B. also acknowledges support from the John D. and Catherine T. MacArthur Foundation, the Alfred P. Sloan Foundation, and the National Science Foundation (BCS-1441502, CAREER PHY-1554488, BCS-1631550, and CNS-1626008). We also thank two anonymous reviewers whose comments greatly improved the quality of this work. The content is solely the responsibility of the authors and does not necessarily represent the official views of any of the funding agencies.Peer reviewedPublisher PD
Extending the definition of modularity to directed graphs with overlapping communities
Complex networks topologies present interesting and surprising properties,
such as community structures, which can be exploited to optimize communication,
to find new efficient and context-aware routing algorithms or simply to
understand the dynamics and meaning of relationships among nodes. Complex
networks are gaining more and more importance as a reference model and are a
powerful interpretation tool for many different kinds of natural, biological
and social networks, where directed relationships and contextual belonging of
nodes to many different communities is a matter of fact. This paper starts from
the definition of modularity function, given by M. Newman to evaluate the
goodness of network community decompositions, and extends it to the more
general case of directed graphs with overlapping community structures.
Interesting properties of the proposed extension are discussed, a method for
finding overlapping communities is proposed and results of its application to
benchmark case-studies are reported. We also propose a new dataset which could
be used as a reference benchmark for overlapping community structures
identification.Comment: 22 pages, 11 figure
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