23,110 research outputs found
Killing vectors and anisotropy
We consider an action that can generate fluids with three unequal stresses
for metrics with a spacelike Killing vector. The parameters in the action are
directly related to the stress anisotropies. The field equations following from
the action are applied to an anisotropic cosmological expansion and an
extension of the Gott-Hiscock cosmic string
Comparison between two mobile absolute gravimeters: optical versus atomic interferometers
We report a comparison between two absolute gravimeters: the LNE-SYRTE cold
atoms gravimeter and FG5#220 of Leibniz Universit\"at of Hannover. They rely on
different principles of operation: atomic and optical interferometry. Both are
movable which enabled them to participated to the last International Comparison
of Absolute Gravimeters (ICAG'09) at BIPM. Immediately after, their bilateral
comparison took place in the LNE watt balance laboratory and showed an
agreement of 4.3 +/- 6.4 {\mu}Gal
Aparente ausência de resistência cruzada entre algumas proteínas de Bacillus thuringiensis em Spodoptera frugiperda
Resumo
The dynamical spin structure factor for the anisotropic spin-1/2 Heisenberg chain
The longitudinal spin structure factor for the XXZ-chain at small wave-vector
q is obtained using Bethe Ansatz, field theory methods and the Density Matrix
Renormalization Group. It consists of a peak with peculiar, non-Lorentzian
shape and a high-frequency tail. We show that the width of the peak is
proportional to q^2 for finite magnetic field compared to q^3 for zero field.
For the tail we derive an analytic formula without any adjustable parameters
and demonstrate that the integrability of the model directly affects the
lineshape.Comment: 4 pages, 3 figures, published versio
Neuropathic pain after breast cancer treatment: characterization and risk factors
Context: Neuropathic pain (NP) may be an important contributor to the morbidity burden of breast cancer.
Objectives: We aimed to quantify the incidence of NP in the first year after diagnosis of breast cancer and to identify its main determinants.
Methods: We performed a prospective cohort study including 506 patients with incident breast cancer, recruited at the Portuguese Institute of Oncology of Porto, and followed for one year; patients with incident NP were additionally evaluated when this condition was diagnosed and after six months, to identify chronic NP.
Results: During the first year, 156 patients were diagnosed with NP (30.8%, 95% CI 27.0–35.0). Anxiety (relative risk [RR] 1.50; 95% CI 1.06–2.13), arm symptoms (RR 1.44; 95% CI 1.02–2.05), cancer Stage III/IV (RR 2.47; 95% CI 1.66–3.66), breast-conserving surgery with axillary lymph node dissection (RR 3.13; 95% CI 1.51–6.48), mastectomy with axillary lymph node dissection (RR 2.52; 95% CI 1.25–5.11), and damaging of the intercostobrachial nerve (RR 2.05; 95% CI 1.25–3.37) were predictors of a higher risk of NP. A total of 97 patients (62.2%, 95% CI 54.4–69.4) diagnosed with NP remained symptomatic after six months.
Conclusion: NP and chronic NP were frequent in this population, being associated with anxiety and arm symptoms before breast cancer treatments and type of surgical management. These results highlight the need for monitoring the occurrence of this neurologic side effect of treatments and to develop strategies for reducing the morbidity burden of breast cancer.The work of F. F. was co-funded by “Fundação para a Ciência e a Tecnologia” (grant number SFRH/BD/92630/2013) and by the “Programa Operacional Capital Humano” (POCH/FSE). Data management activities were supported by the Chair on Pain Medicine of the Faculty of Medicine, University of Porto and by the Grünenthal Foundation—Portugal. The authors declare no conflicts of interests
Pet ownership during the first 5 years after breast cancer diagnosis in the NEON-BC cohort
Background Although human-animal interactions (HAI) have been associated with health benefits, they have not been extensively studied among cancer patients nor which factors may influence HAI during cancer survivorship. Therefore, this study aims to describe pet ownership in a breast cancer cohort within 5 years post-diagnosis and to identify associated factors. Methods Four hundred sixty-six patients from the NEON-BC cohort were evaluated. Four groups of pet ownership over the 5 years were defined: 'never had', 'stopped having', 'started having' and 'always had'. Multinomial logistic regression was used to quantify the association between the patient characteristics and the groups defined (reference: 'never had'). Results 51.7% of patients had pets at diagnosis, which increased to 58.4% at 5 years; dogs and cats were the most common. Women presenting depressive symptoms and poor quality of life were more likely to stop having pets. Older and unpartnered women were less likely to start having pets. Those retired, living outside Porto, having diabetes or having owned animals during adulthood were more likely to start having pets. Women with higher education and unpartnered were less likely to always have pets. Those living in larger households, with other adults or having animals throughout life, were more likely to always have pets. Obese women had lower odds of stopping having dogs/cats. Women submitted to neoadjuvant chemotherapy and longer chemotherapy treatments were more likely to stop having dogs/cats. Conclusions Pet ownership changed over the 5 years and is influenced by sociodemographic, clinical and treatment characteristics, patient-reported outcomes and past pet ownership, reflecting the importance of HAI during cancer survivorship.This work was funded by FEDER through the Operational Programme Competitiveness and Internationalization and national funding from the Foundation for Science and Technology-FCT (Portuguese Ministry of Science, Technology and Higher Education) under the project 'A five-year prospective cohort study on the neurological complications of breast cancer: frequency and impact in patient-reported outcomes' (POCI-01-0145-FEDER016867, Ref. PTDC/DTP-EPI/7183/2014), and national funding from FCT under the Unidade de Investigacao em Epidemiologia-Instituto de Saude Publica da Universidade do Porto (EPIUnit) (UIDB/04750/2020). Individual grants attributed to NA (SFRH/BD/119390/2016) and FF (SFRH/BD/92630/2013) were funded by FCT and the 'Programa Operacional Capital Humano' (POCH/FSE). Data management activities up to the first year of follow-up were supported by the Chair on Pain Medicine of the Faculty of Medicine, University of Porto and by the Grunenthal Foundation-Portugal
Surface modification of Co-doped ZnO nanocrystals and its effects on the magnetic properties
A series of chemically prepared Co2+-doped ZnO colloids has been surface modified either by
growing shells of ZnSe or by the in situ encapsulation in poly styrene . The surface modification
effects using these two distinct chemical strategies on the magnetic properties of the nanocrystals
were probed by electron paramagnetic resonance EPR . Structural characterization by means of
x-ray diffraction and transmission electron microscopy gave no evidence of second phase formation
within the detection limits of the used equipment. The EPR analysis was carried out by simulations
of the powderlike EPR spectra. The results confirm that in the core of these nanocrystals Co was
incorporated as Co2+, occupying the Zn2+ sites in the wurtzite structure of ZnO. Additionally we
identify two Co signals stemming from the nanocrystals’ shell. The performed surface modifications
clearly change the relative intensity of the EPR spectrum components, revealing the core and shell
signals
Tamanho do genoma em coqueiro (Cocos nucifera L.) via citometria de Fluxo.
O objetivo do presente trabalho foi determinar o tamanho do genoma do coqueiro (Cocos nucífera L.) via determinação do conteúdo de DNA estimado via citometria de fluxo. Quatorze genótipos de coco, seis do tipo anão e oito do tipo gigante, foram utilizados nesse estudo. Para tal, amostras de folíolos medindo aproximadamente 0,5 cm2, por genótipo foram maceradas em solução tampão e filtradas para obtenção de uma suspensão dos núcleos. Posteriormente, os núcleos foram coloridos com iodeto de propídeo e em seguida foi adicionado RNase em cada amostra. Como padrão interno foi utilizado a cultivar CE-777 de milho (Zea mays L.). Após 30 minutos, as amostras foram analisadas em citômetro de fluxo (Partec PA II); para cada genótipo foi feito a leitura de cinco amostras. O conteúdo 2C de DNA de cada genótipo foi determinado, com médias variando de 2,74 pg a 2,86 pg, sendo a média geral 2,80 pg o que corresponde a 2.744 Mpb. O conteúdo de DNA do grupo Gigante foi o mais varável sendo o maior conteúdo estimado para o Gigante de Rennel, e o menor conteúdo para Gigante do Oeste Africano; o grupo Anão teve uma menor variação. A média do conteúdo 2C de DNA do grupo gigante foi de 2,80 pg e a do grupo Anão foi de 2,78pg. Os coeficientes de variação variaram de 2,5% a 3,1%, o que indica a precisão das medições. O teste Scott e Knott a 5% de probabilidade, agrupou os genótipos em 4 classes de acordo com as médias do conteúdo de DNA. Os resultados permitiram concluir que a espécie apresenta baixo conteúdo de DNA quando comparada com outros membros da família Arecaceae
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