2,544 research outputs found

    Production and Characterization of Femtosecond-Laser-Induced Air Plasma

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    The purpose of this research was to produce, characterize, and optimize laser induced air plasma as a preliminary step in using the plasma as a source of terahertz radiation. An 800 nanometer, 50 femtosecond, 0.75 Watt, pulsed Ti:Sapphire laser system was used as the source infrared beam. A beam expander was used to expand the beam to a diameter of approximately 6.5 mm, and the beam was focused through a 25 mm focal length achromatic lens to produce laser-induced plasma in ambient air. A 40 kHz ultrasonic transducer was used to detect the plasma. A second harmonic generation crystal was placed within the beam expander to generate 400 nm blue light, enabling production of THz in the plasma via four wave mixing; a third-order nonlinear process. While plasma-produced THz was not detected, all the preliminary groundwork was accomplished, including full characterization of the plasma, blue light, and alignment of the system to generate and detect THz. The electro-optic detection apparatus was assembled, aligned and used to successfully detect a diagnostic THz signal

    Continuous Integration of Architectural Performance Models with Parametric Dependencies – The CIPM Approach

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    Explicitly considering the software architecture supports efficient assessments of quality attributes. In particular, Architecture-based Performance Prediction (AbPP) supports performance assessment for future scenarios (e.g., alternative workload, design, deployment, etc.) without expensive measurements for all such alternatives. However, accurate AbPP requires an up-to-date architectural Performance Model (aPM) that is parameterized over factors impacting performance like input data characteristics. Especially in agile development, keeping such a parametric aPM consistent with software artifacts is challenging due to frequent evolutionary, adaptive and usage-related changes. The shortcoming of existing approaches is the scope of consistency maintenance since they do not address the impact of all aforementioned changes. Besides, extracting aPM by static and/or dynamic analysis after each impacting change would cause unnecessary monitoring overhead and may overwrite previous manual adjustments. In this article, we present our Continuous Integration of architectural Performance Model (CIPM) approach, which automatically updates the parametric aPM after each evolutionary, adaptive or usage change. To reduce the monitoring overhead, CIPM calibrates just the affected performance parameters (e.g., resource demand), using adaptive monitoring. Moreover, CIPM proposes a self-validation process that validates the accuracy, manages the monitoring and recalibrates the inaccurate parts. As a result, CIPM will automatically keep the aPM up-to-date throughout the development time and operation time, which enables AbPP for a proactive identification of upcoming performance problems and evaluating alternatives at low costs. CIPM is evaluated using three case studies, considering (1) the accuracy of the updated aPMs and associated AbPP and (2) the applicability of CIPM in terms of the scalability and the required monitoring overhead

    Ion antiport accelerates photosynthetic acclimation in fluctuating light environments

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    Many photosynthetic organisms globally, including crops, forests and algae, must grow in environments where the availability of light energy fluctuates dramatically. How photosynthesis maintains high efficiency despite such fluctuations in its energy source remains poorly understood. Here we show that Arabidopsis thaliana ​K+ efflux antiporter (​KEA3) is critical for high photosynthetic efficiency under fluctuating light. On a shift from dark to low light, or high to low light, ​kea3 mutants show prolonged dissipation of absorbed light energy as heat. ​KEA3 localizes to the thylakoid membrane, and allows proton efflux from the thylakoid lumen by proton/potassium antiport. ​KEA3’s activity accelerates the downregulation of pH-dependent energy dissipation after transitions to low light, leading to faster recovery of high photosystem II quantum efficiency and increased ​CO2 assimilation. Our results reveal a mechanism that increases the efficiency of photosynthesis under fluctuating light. [EN]This project was funded by the Carnegie Institution for Science, by ERDF-cofinanced grants from the Ministry of Economy and Competitiveness (BIO2012-33655) and Junta de Andalucia (CVI-7558) to K.V., the Natural Sciences and Engineering Research Council of Canada (NSERC) PGS-D3 scholarship to L.P. and Deutsche Forschungsgemeinschaft grants (JA 665/10-1 and GRK 1525 to P.J.; AR 808/1-1 to U.A.).Peer reviewe

    Circulating testosterone and prostate-specific antigen in nipple aspirate fluid and tissue are associated with breast cancer.

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    Preliminary evidence has associated testosterone and prostate-specific antigen (PSA) with breast cancer. Our objective was to determine whether a) testosterone levels in nipple aspirate fluid (NAF), serum, or breast tissue are associated with breast cancer; b) testosterone levels in serum are associated with levels in NAF; c) PSA in NAF, serum, or breast tissue is associated with breast cancer; and d) serum PSA is associated with NAF PSA levels. We obtained 342 NAF specimens from 171 women by means of a modified breast pump. Additionally, we collected 201 blood samples from 99 women and 51 tissue samples from 41 subjects who underwent surgical resection for suspected disease. Women currently using birth control pills or hormone replacement therapy were excluded from the study. Controlling for age and menopausal status, serum testosterone was significantly increased in women with breast cancer (p = 0.002). NAF and serum testosterone levels were not associated. Neither NAF nor tissue testosterone was associated with breast cancer. Controlling for menopausal status and age, NAF PSA was significantly decreased in women with breast cancer (p \u3c 0.001). We did not find serum PSA to be associated with breast cancer, although we found an indication that, in postmenopausal women, its levels were lower in women with cancer. Serum PSA was associated with NAF PSA in postmenopausal women (p \u3c 0.001). PSA levels in cancerous tissue were significantly lower than in benign breast specimens from subjects without cancer (p = 0.011), whereas levels of PSA in histologically benign specimens from subjects with cancer were intermediate. Our results suggest that serum testosterone is increased and NAF PSA is decreased in women with breast cancer, with PSA expression being higher in normal than in cancerous breast tissues. NAF and serum PSA levels in postmenopausal women are correlated, suggesting that as laboratory assessment of PSA becomes more sensitive, serum PSA may become useful in identifying women with breast cancer

    Presynaptic adenosine receptor-mediated regulation of diverse thalamocortical short-term plasticity in the mouse whisker pathway

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    Short-term synaptic plasticity (STP) sets the sensitivity of a synapse to incoming activity and determines the temporal patterns that it best transmits. In “driver” thalamocortical (TC) synaptic populations, STP is dominated by depression during stimulation from rest. However, during ongoing stimulation, lemniscal TC connections onto layer 4 neurons in mouse barrel cortex express variable STP. Each synapse responds to input trains with a distinct pattern of depression or facilitation around its mean steady-state response. As a result, in common with other synaptic populations, lemniscal TC synapses express diverse rather than uniform dynamics, allowing for a rich representation of temporally varying stimuli. Here, we show that this STP diversity is regulated presynaptically. Presynaptic adenosine receptors of the A1R type, but not kainate receptors (KARs), modulate STP behavior. Blocking the receptors does not eliminate diversity, indicating that diversity is related to heterogeneous expression of multiple mechanisms in the pathway from presynaptic calcium influx to neurotransmitter release

    RNA dimerization plays a role in ribosomal frameshifting of the SARS coronavirus

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    Messenger RNA encoded signals that are involved in programmed -1 ribosomal frameshifting (-1 PRF) are typically two-stemmed hairpin (H)-type pseudoknots (pks). We previously described an unusual three-stemmed pseudoknot from the severe acute respiratory syndrome (SARS) coronavirus (CoV) that stimulated -1 PRF. The conserved existence of a third stem–loop suggested an important hitherto unknown function. Here we present new information describing structure and function of the third stem of the SARS pseudoknot. We uncovered RNA dimerization through a palindromic sequence embedded in the SARS-CoV Stem 3. Further in vitro analysis revealed that SARS-CoV RNA dimers assemble through ‘kissing’ loop–loop interactions. We also show that loop–loop kissing complex formation becomes more efficient at physiological temperature and in the presence of magnesium. When the palindromic sequence was mutated, in vitro RNA dimerization was abolished, and frameshifting was reduced from 15 to 5.7%. Furthermore, the inability to dimerize caused by the silent codon change in Stem 3 of SARS-CoV changed the viral growth kinetics and affected the levels of genomic and subgenomic RNA in infected cells. These results suggest that the homodimeric RNA complex formed by the SARS pseudoknot occurs in the cellular environment and that loop–loop kissing interactions involving Stem 3 modulate -1 PRF and play a role in subgenomic and full-length RNA synthesis

    The strength of the association between heterozygosity and probability of interannual local recruitment increases with environmental harshness in blue tits

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    The extent of inbreeding depression and the magnitude of heterozygosity–fitness correlations (HFC) have been suggested to depend on the environmental context in which they are assayed, but little evidence is available for wild populations. We combine extensive molecular and capture–mark–recapture data from a blue tit (Cyanistes caeruleus) population to (1) analyze the relationship between heterozygosity and probability of interannual adult local recruitment and (2) test whether environmental stress imposed by physiologically suboptimal temperatures and rainfall influence the magnitude of HFC. To address these questions, we used two different arrays of microsatellite markers: 14 loci classified as neutral and 12 loci classified as putatively functional. We found significant relationships between heterozygosity and probability of interannual local recruitment that were most likely explained by variation in genomewide heterozygosity. The strength of the association between heterozygosity and probability of interannual local recruitment was positively associated with annual accumulated precipitation. Annual mean heterozygosity increased over time, which may have resulted from an overall positive selection on heterozygosity over the course of the study period. Finally, neutral and putatively functional loci showed similar trends, but the former had stronger effect sizes and seemed to better reflect genomewide heterozygosity. Overall, our results show that HFC can be context dependent, emphasizing the need to consider the role of environmental heterogeneity as a key factor when exploring the consequences of individual genetic diversity on fitness in natural populations.Peer reviewe

    Service User Involvement - SUI Newsletter - Ausgabe August 2022

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    Dieser Newsletter informiert jährlich über die Aktivitäten des deutschsprachigen Netzwerkes zu Service User Involvement - Erfahrungswissen in der Hochschulbildung. Der Newsletter informiert in seiner Ausgabe 2022 über folgende Aktivitäten: David Dörrer und Karin Terfloth berichten in ihrem Beitrag „Professionalisierung des Service User Involvements durch Qualifikationsangebote“ über den Einsatz von Bildungsfachkräften. Dabei nehmen sie die Benefits für die Menschen mit Behinderungserfahrungen in den Blick und stellen sich die Frage, wie die Qualifizierung ggf. Perspektiven bzw. die Vertretung der Peergruppe verändern kann. In ihrem Beitrag „Service User Involvement in der Ausbildung in Zürich: Ein Pilotprojekt“ stellen Gisela Meier und Michael Herzig eine tatkräftige Initiative für die Implementierung von SUI an der Fachhochschule Zürich vor. Für die Erstellung des Konzeptes werden Studierende, Lehrende, Adressat*innen und Sozialarbeitende einbezogen. Florian Günthert von der FH Esslingen schreibt in seinem Beitrag „Wie erlebt man Wohnungslosigkeit?“ aus der Perspektive eines Studenten über ein SUI Projekt. Aus der Recherche über Wohnungslosigkeit kam das Interesse zustande, die Stimmen derjenigen zu finden, die betroffen sind. Herausgekommen ist eine Blog-Website mit Aussagen und Berichten von interviewten Menschen und Textgrafiken. Ein weiterer Einblick aus der Lehre kommt aus der FH Potsdam von Olivia Aufschlag und Elena Sollmann. Sie berichten in dem Beitrag „Das Format der Werkstätten an der FH Potsdam – Forschungsfragen von Studierenden zu SUI“ von ihren Forschungsergebnissen über die Motivation von Service Usern, ihr Wissen mit angehenden Sozialarbeiter*innen zu teilen. Gerahmt wird der Beitrag durch eine kleine Einleitung zu dem Lehr-Lern-Format der Werkstatt von Marlene-Anne Dettmann. Katharina Scholz bietet in ihrem Beitrag „SUI-Talk mit Erfahrungsexpertinnen und Studentinnen der Sozialen Arbeit auf der Jahrestagung der DGSA“ eine kleine Nachlese zu unserem Panel. Zu Wort kommen dabei auch beteiligte Studentinnen der FH Esslingen und ihre Perspektive auf SUI. Zusätzlich gibt es noch Links zu weiteren Materialien. Sylvia Fahr-Armbruster, Conny Birkemeyer und Oscar Garcia stellen in ihrem Beitrag „Recovery College Stuttgart“ einen neuen Ort der „lebendigen Selbsthilfeszene“ vor. Nach dem Motto „Erfahrungswissen lebendig teilen“ laden Menschen mit Krankheitserfahrungen zum Austausch ein und sind offen für spannende Kooperationen mit Hochschulen. Mit dem Beitrag „SUI in Europa – persönliche Eindrücke aus Nottingham und Amsterdam“ teilt Marlene-Anne Dettmann ihre Beobachtungen zu den Entwicklungen im europäischen Raum, beispielsweise mit praktischen Umsetzungsideen und der sprachlichen Verwendung von „people with lived experience“. Am Ende des Newsletters finden Sie noch Hinweise über aktuelle Publikationen und anstehende Termine zum Thema Service User Involvement. Ich wünsche viel Spaß beim Lesen und freue mich auf Ihre Rückmeldungen und neuen Berichte.Unknow

    Health facility-based Active Management of the Third Stage of Labor: findings from a national survey in Tanzania

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    Hemorrhage is the leading cause of obstetric mortality. Studies show that Active Management of Third Stage of Labor (AMTSL) reduces Post Partum Hemorrhage (PPH). This study describes the practice of AMTSL and barriers to its effective use in Tanzania. A nationally-representative sample of 251 facility-based vaginal deliveries was observed for the AMTSL practice. Standard Treatment Guidelines (STG), the Essential Drug List and medical and midwifery school curricula were reviewed. Drug availability and storage conditions were reviewed at the central pharmaceutical storage site and pharmacies in the selected facilities. Interviews were conducted with hospital directors, pharmacists and 106 health care providers in 29 hospitals visited. Data were collected between November 10 and December 15, 2005. Correct practice of AMTSL according to the ICM/FIGO definition was observed in 7% of 251 deliveries. When the definition of AMTSL was relaxed to allow administration of the uterotonic drug within three minutes of fetus delivery, the proportion of AMTSL use increased to 17%. The most significant factor contributing to the low rate of AMTSL use was provision of the uterotonic drug after delivery of the placenta. The study also observed potentially-harmful practices in approximately 1/3 of deliveries. Only 9% out of 106 health care providers made correct statements regarding the all three components of AMTSL. The national formulary recommends ergometrine (0.5 mg/IM) or oxytocin (5 IU/IM) on delivery of the anterior shoulder or immediately after the baby is delivered. Most of facilities had satisfactory stores of drugs and supplies. Uterotonic drugs were stored at room temperature in 28% of the facilities. The knowledge and practice of AMTSL is very low and STGs are not updated on correct AMTSL practice. The drugs for AMTSL are available and stored at the right conditions in nearly all facilities. All providers used ergometrine for AMTSL instead of oxytocin as recommended by ICM/FIGO. The study also observed harmful practices during delivery. These findings indicate that there is a need for updating the STGs, curricula and training of health providers on AMTSL and monitoring its practice

    Measurement of the cross-section and charge asymmetry of WW bosons produced in proton-proton collisions at s=8\sqrt{s}=8 TeV with the ATLAS detector

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    This paper presents measurements of the W+μ+νW^+ \rightarrow \mu^+\nu and WμνW^- \rightarrow \mu^-\nu cross-sections and the associated charge asymmetry as a function of the absolute pseudorapidity of the decay muon. The data were collected in proton--proton collisions at a centre-of-mass energy of 8 TeV with the ATLAS experiment at the LHC and correspond to a total integrated luminosity of 20.2~\mbox{fb^{-1}}. The precision of the cross-section measurements varies between 0.8% to 1.5% as a function of the pseudorapidity, excluding the 1.9% uncertainty on the integrated luminosity. The charge asymmetry is measured with an uncertainty between 0.002 and 0.003. The results are compared with predictions based on next-to-next-to-leading-order calculations with various parton distribution functions and have the sensitivity to discriminate between them.Comment: 38 pages in total, author list starting page 22, 5 figures, 4 tables, submitted to EPJC. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/STDM-2017-13
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