1,089 research outputs found
Dirac Gauginos, Negative Supertraces and Gauge Mediation
In an attempt to maximize General Gauge Mediated parameter space, I propose
simple models in which gauginos and scalars are generated from disconnected
mechanisms. In my models Dirac gauginos are generated through the supersoft
mechanism, while independent R-symmetric scalar masses are generated through
operators involving non-zero messenger supertrace. I propose several new
methods for generating negative messenger supertraces which result in viable
positive mass squareds for MSSM scalars. The resultant spectra are novel,
compressed and may contain light fermionic SM adjoint fields.Comment: 16 pages 3 figure
Farnesol induces cell detachment from established S. epidermidis biofilms
Antibiotic resistance is a serious problem in Staphylococcus epidermidis infections as many clinical isolates of this organism are resistant to up to eight different antibiotics. The increased resistance to conventional antibiotic therapy has lead to the search for new antimicrobial therapeutic agents. Farnesol, an essential oil found in many plants, has been shown to be active against S. epidermidis. Using a type control strain we recently described that although farnesol was not efficient at killing biofilm bacteria, a strong reduction on biofilm biomass was detected, and we hypothesize that farnesol could, somehow, induce biofilm detachment. In this report, to test our hypothesis we used 36 representative clinical strains of S. epidermidis from different geographic locations and characterized them in terms of genetic variability by multilocus sequence typing and staphylococcal chromosome cassette mec. Strains were tested for biofilm formation, and the presence of ica, bhp and aap genes was determined. Stronger biofilms had always the presence of ica operon but often co-harbored bhp and aap genes. Farnesol was then used in biofilm-forming strains, and biofilm detachment was detected in half of the strains tested. Furthermore, we also showed that farnesol inability to kill biofilm bacteria was not the result of the biofilm structure but was related to high cell density. Our results demonstrate, for the first time, that the biomass reduction previously found by us, and many other groups, is the result not of cell killing but instead is the result of biofilm detachment.We thank Herminia de Lencastre for reviewing the manuscript. Support for this work was provided by project P-99911 from Fundacao Calouste Gulbenkian and CONCORD-HEALTH-F3-2008/Project Number 222718/European Commission. This work was also supported by Fundacao para a Ciencia e a Tecnologia through grant #PEst-OE/EQB/LA0004/2011 awarded to ITQB
Scale of Auditory Behaviors e testes auditivos comportamentais para avaliação do processamento auditivo em crianças falantes do português europeu
PURPOSE: The objective of this research was to assess the auditory abilities of Portuguese children and compare such abilities to the score of the Scale of Auditory Behaviors (SAB).
METHODS: Fifty-one children were evaluated with audiometry, speech audiometry, acoustic immittance measures, and eight behavioral tests involving dichotic listening, monotic listening, temporal processing, and sound localization. Their parents filled in the SAB questionnaire adapted to European A. SAB scores and auditory tests scores were submitted to Pearson's correlation coefficient.
RESULTS: There is significant correlation between the score on SAB questionnaire and the auditory processing tests. The greatest coefficient was observed in temporal processing test (p=0.000).
CONCLUSION: There was correlation between the score of SAB and the performance in auditory processing tests, suggesting that the SAB may be used for auditory processing screening.OBJETIVO: Investigar as habilidades auditivas de crianças portuguesas e verificar se há correlação entre aquelas e o escore do Scale of Auditory Behaviors (SAB).
MÉTODOS: Todas as crianças foram submetidas a audiometria tonal, logoaudiometria, medidas de imitância acústica e oito testes comportamentais do processamento auditivo, envolvendo tarefas de escuta dicótica, escuta monótica, processamento temporal e localização sonora. Os pais das 51 crianças portuguesas avaliadas preencheram o questionário SAB adaptado ao português europeu. Foram calculados os valores do coeficiente de correlação de Pearson entre os escores obtidos no questionário e os dos testes do processamento auditivo.
RESULTADOS: Observou-se correlação significativa entre o escore do questionário e o dos testes comportamentais, tendo a maior sido observada nos testes relacionados ao processamento temporal (p=0,000).
CONCLUSÃO: Houve correlação entre o escore da SAB e os resultados obtidos nos testes auditivos comportamentais em crianças portuguesas, sugerindo que este questionário pode ser utilizado em triagem do processamento auditivo.CIEC – Research Centre on Child Studies, UM (FCT R&D 317
Critical review on biofilm methods
Biofilms are widespread in nature and constitute an important strategy implemented by microorganisms to survive in sometimes harsh environmental conditions. They can be beneficial or have a negative impact particularly when formed in industrial settings or on medical devices. As such, research into the formation and elimination of biofilms is important for many disciplines. Several new methodologies have been recently developed for, or adapted to, biofilm studies that have contributed to deeper knowledge on biofilm physiology, structure and composition. In this review, traditional and cutting-edge methods to study biofilm biomass, viability, structure, composition and physiology are addressed. Moreover, as there is a lack of consensus among the diversity of techniques used to grow and study biofilms. This review intends to remedy this, by giving a critical perspective, highlighting the advantages and limitations of several methods. Accordingly, this review aims at helping scientists in finding the most appropriate and up-to-date methods to study their biofilms.The authors would like to acknowledge the support from the EU COST Action BacFoodNet FA1202
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
New insights into the photochemistry of carotenoid spheroidenone in light-harvesting complex 2 from the purple bacterium Rhodobacter sphaeroides
Light-harvesting complex 2 (LH2) from the
semi-aerobically grown purple phototrophic bacterium
Rhodobacter sphaeroides was studied using optical (static
and time-resolved) and resonance Raman spectroscopies.
This antenna complex comprises bacteriochlorophyll
(BChl) a and the carotenoid spheroidenone, a ketolated
derivative of spheroidene. The results indicate that the
spheroidenone-LH2 complex contains two spectral forms
of the carotenoid: (1) a minor, ‘‘blue’’ form with an S2
(11
Bu
?) spectral origin band at 522 nm, shifted from the
position in organic media simply by the high polarizability
of the binding site, and (2) the major, ‘‘red’’ form with the
origin band at 562 nm that is associated with a pool of
pigments that more strongly interact with protein residues,
most likely via hydrogen bonding. Application of targeted
modeling of excited-state decay pathways after carotenoid
excitation suggests that the high (92%) carotenoid-to-BChl
energy transfer efficiency in this LH2 system, relative to
LH2 complexes binding carotenoids with comparable
double-bond conjugation lengths, derives mainly from
resonance energy transfer from spheroidenone S2 (11
Bu
?)
state to BChl a via the Qx state of the latter, accounting for
60% of the total transfer. The elevated S2 (11
Bu
?) ? Qx
transfer efficiency is apparently associated with substantially
decreased energy gap (increased spectral overlap)
between the virtual S2 (11
Bu
?) ? S0 (11
Ag
-) carotenoid
emission and Qx absorption of BChl a. This reduced
energetic gap is the ultimate consequence of strong carotenoid–protein
interactions, including the inferred hydrogen
bondin
Biofilm development by clinical isolates of Staphylococcus spp. from retrieved orthopedic prostheses
Understanding missed opportunities for more timely diagnosis of cancer in symptomatic patients after presentation.
The diagnosis of cancer is a complex, multi-step process. In this paper, we highlight factors involved in missed opportunities to diagnose cancer more promptly in symptomatic patients and discuss responsible mechanisms and potential strategies to shorten intervals from presentation to diagnosis. Missed opportunities are instances in which post-hoc judgement indicates that alternative decisions or actions could have led to more timely diagnosis. They can occur in any of the three phases of the diagnostic process (initial diagnostic assessment; diagnostic test performance and interpretation; and diagnostic follow-up and coordination) and can involve patient, doctor/care team, and health-care system factors, often in combination. In this perspective article, we consider epidemiological 'signals' suggestive of missed opportunities and draw on evidence from retrospective case reviews of cancer patient cohorts to summarise factors that contribute to missed opportunities. Multi-disciplinary research targeting such factors is important to shorten diagnostic intervals post presentation. Insights from the fields of organisational and cognitive psychology, human factors science and informatics can be extremely valuable in this emerging research agenda. We provide a conceptual foundation for the development of future interventions to minimise the occurrence of missed opportunities in cancer diagnosis, enriching current approaches that chiefly focus on clinical decision support or on widening access to investigations.We acknowledge the helpful and incisive comments by Dr Rikke Sand Andersen (Aarhus University, Denmark) in conceptualising this piece and in drafts of the manuscript. The work is independent research supported by different funding schemes. GL was supported by a Post-Doctoral Fellowship by the National Institute for Health Research (PDF-2011-04-047) until the end of 2014 and by a Cancer Research UK Clinician Scientist Fellowship award (A18180) from 2015. HS is supported by the VA Health Services Research and Development Service (CRE 12-033; Presidential Early Career Award for Scientists and Engineers USA 14-274), the VA National Center for Patient Safety, the Agency for Health Care Research and Quality (R01HS022087) and in part by the Houston VA HSR&D Center for Innovations in Quality, Effectiveness and Safety (CIN 13–413). PV was supported by CaP, funded by The Danish Cancer Society and the Novo Nordisk Foundation.This is the final version of the article. It first appeared at http://dx.doi.org/10.1038/bjc.2015.4
Home Telehealth Uptake and Continued Use Among Heart Failure and Chronic Obstructive Pulmonary Disease Patients: a Systematic Review
Background
Home telehealth has the potential to benefit heart failure (HF) and chronic obstructive pulmonary disease (COPD) patients, however large-scale deployment is yet to be achieved.
Purpose
The aim of this review was to assess levels of uptake of home telehealth by patients with HF and COPD and the factors that determine whether patients do or do not accept and continue to use telehealth.
Methods
This research performs a narrative synthesis of the results from included studies.
Results
Thirty-seven studies met the inclusion criteria. Studies that reported rates of refusal and/or withdrawal found that almost one third of patients who were offered telehealth refused and one fifth of participants who did accept later abandoned telehealth. Seven barriers to, and nine facilitators of, home telehealth use were identified.
Conclusions
Research reports need to provide more details regarding telehealth refusal and abandonment, in order to understand the reasons why patients decide not to use telehealth
Multi-messenger observations of a binary neutron star merger
On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta
- …
