9,447 research outputs found
An OpenSHMEM Implementation for the Adapteva Epiphany Coprocessor
This paper reports the implementation and performance evaluation of the
OpenSHMEM 1.3 specification for the Adapteva Epiphany architecture within the
Parallella single-board computer. The Epiphany architecture exhibits massive
many-core scalability with a physically compact 2D array of RISC CPU cores and
a fast network-on-chip (NoC). While fully capable of MPMD execution, the
physical topology and memory-mapped capabilities of the core and network
translate well to Partitioned Global Address Space (PGAS) programming models
and SPMD execution with SHMEM.Comment: 14 pages, 9 figures, OpenSHMEM 2016: Third workshop on OpenSHMEM and
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Low frequency sound propagation in activated carbon
Activated carbon can adsorb and desorb gas molecules onto and off its surface. Research has examined
whether this sorption affects low frequency sound waves, with pressures typical of audible
sound, interacting with granular activated carbon. Impedance tube measurements were undertaken
examining the resonant frequencies of Helmholtz resonators with different backing materials. It
was found that the addition of activated carbon increased the compliance of the backing volume.
The effect was observed up to the highest frequency measured (500 Hz), but was most significant at
lower frequencies (at higher frequencies another phenomenon can explain the behavior). An apparatus
was constructed to measure the effective porosity of the activated carbon as well as the number
of moles adsorbed at sound pressures between 104 and 118 dB and low frequencies between 20
and 55 Hz. Whilst the results were consistent with adsorption affecting sound propagation, other
phenomena cannot be ruled out. Measurements of sorption isotherms showed that additional energy
losses can be caused by water vapor condensing onto and then evaporating from the surface of the
material. However, the excess absorption measured for low frequency sound waves is primarily
caused by decreases in surface reactance rather than changes in surface resistance
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Up and away: ontogenic transference as a pathway for aerial dispersal of microplastics
Microplastics (MPs) are ubiquitous pollutants found in marine, freshwater and terrestrial ecosystems. With so many MPs in aquatic systems it is inevitable that they will be ingested by aquatic organisms, and be transferred up through the food chain. However, to date, no study has considered whether MPs can be transmitted by means of ontogenic transference i.e. between life stages that utilise different habitats. Here, we determine whether fluorescent polystyrene beads could transfer between Culex mosquito life stages and, particularly, could move into the flying adult stage. We show for the first time that MPs can be transferred ontogenically from a feeding (larva) into a non-feeding (pupa) life stage and subsequently into the adult terrestrial life stage. However, transference is dependent on particle size, with smaller 2 µm MPs transferring readily into pupae and adult stages, whilst 15 µm MPs transferred at a significantly reduced rate. Microplastics appear to accumulate in the Malpighian tubule renal excretion system. The transfer of MPs to the adults represents a potential aerial pathway to contamination of new environments. Thus, any organism that feeds on terrestrial life phases of freshwater insects could be impacted by MPs found in aquatic ecosystems
The role of ultrasound imaging in the management of partial placental retention after third trimester livebirth
Objectives: To evaluate the impact of different ultrasound signs in the management and the role of ultrasound guidance in the surgical evacuation of partial placental tissue retention.Methods: This is an observational cohort study and retrospective case assessment of 82 patients with clinical symptoms of partial placental retention following a third trimester singleton livebirth between January 2013 and May 2019. The ultrasound signs were recorded using a standardized protocol and the outcome of the management strategy and the use of ultrasound guidance during any surgical procedure was evaluated.Results: Out of the 64 patients who had a vaginal birth, 25 (39.1%) had a manual removal of the placenta at delivery. Fifteen patients were confirmed as not having retained placental tissue and did not require further treatment. Four patients were referred after failed surgical management and four after failed conservative management. All surgical procedures were vacuum aspiration and forceps removal under continuous ultrasound guidance. A significantly lower gestational age at delivery (p < .05), shorter interval between delivery and ultrasound diagnosis (p < .05) and lower number of patients presenting with heavy bleeding was found in the conservative compared to the surgical management subgroups (p < .05). The incidence of feeding vessels was significantly (p < .05) higher in the surgical than in the conservative management subgroups and associated with increased myometrial vascularity. Six patients developed intra-uterine adhesions. In four of these cases, ultrasound examination showed a hyperechoic mass surrounded by normal myometrial vascularity and no feeding vessel.Conclusions: Ultrasound imaging accurately differentiated between patient with and without partial placental retention after third trimester livebirth. Ultrasound-guided vacuum aspiration is safe and efficient in these cases
Ultrasound diagnosis of complete and partial hydatidiform moles in early pregnancy failure: An inter-observer study
We evaluated the accuracy of the ultrasound signs suggestive of complete hydatidiform mole (CHM) and partial hydatidiform mole (PHM) in a cohort of women with histologically confirmed hydatidiform mole (HM) who presented with early pregnancy failure, including 103 CHM and 95 PHM for which ultrasound images were available. The accuracy of the differential diagnosis was significantly (p < 0.001) greater during secondary examination of ultrasound images compared with the original primary ultrasound examination. The interobserver agreement analysis indicated only a fair to moderate agreement between the two examinations (kappa value 0.41; 95% CI 0.29–0.53). Most HM present as early pregnancy failure and identification of early ultrasound signs can improve the differential diagnosis between CHM and PHM
How many sentinel nodes should be harvested in oral squamous cell carcinoma?
The number of harvested lymph nodes when performing sentinel lymph node (SLN) biopsy remains controversial. The aim of this study was to examine the maximum number of nodes to be harvested for histopathological analysis. We also wanted to determine if the level of radioactivity within a SLN or its size were indicators for the likelihood of nodal metastases. The SLNs from 34 neck dissection specimens from patients with T1/T2 N0 oral and oropharyngeal carcinomas were included. Altogether 76 SLNs were measured for radioactivity and lymph node dimensions and volume. Tumour was identified in 16 of 76 nodes (positive nodes), and the remaining 60 nodes were free from tumour (negative nodes). In 9 of 16 cases, metastases were in the hottest node. Two patients had more than one positive SLN: the first and fourth hottest in one and the second and fourth hottest nodes in another contained tumour. However, all patients would have been staged accurately if only the hottest three sentinel nodes had been retrieved. Lymph nodes that contained tumour had a greater maximum diameter than non-metastatic SLNs. To stage the neck accurately, only the three hottest lymph nodes required sampling
The effect of calorie restriction on mouse skeletal muscle is sex, strain and time-dependent
Loss of skeletal muscle mass and function occurs with increasing age. Calorie restriction (CR) increases the lifespan of C57Bl/6 mice, but not in the shorter-lived DBA/2 strain. There is some evidence that calorie restriction reduces or delays many of the age-related defects that occur in rodent skeletal muscle. We therefore investigated the effect of short (2.5 month) and longer term (8.5 and 18.5 months) CR on skeletal muscle in male and female C57Bl/6 and DBA/2 mice. We found that short-term CR increased the satellite cell number and collagen VI content of muscle, but resulted in a delayed regenerative response to injury.Consistent with this, the in vitro proliferation of satellite cells derived from these muscles was reduced by CR. The percentage of stromal cells, macrophages, hematopoietic stem cells and fibroadipogenic cells in the mononucleated cell population derived from skeletal muscle was reduced by CR at various stages. But overall, these changes are neither consistent over time, nor between strain and sex. The fact that changes induced by CR do not persist with time and the dissimilarities between the two mouse strains, combined with sex differences, urge caution in applying CR to improve skeletal muscle function across the lifespan in humans
High birth weight as an important risk factor for infant leukemia
In this paper, we compared the birth weight distribution among 201 infant leukaemia (IL) cases with that of 440 noncancer controls enrolled in Brazil in 1999–2005. Compared with the general population and the stratum 2500–2999 g as reference, IL cases weighing 3000–3999 g presented an odds ratio (OR) of 1.68 (95% CI: 1.03–2.76), and those of 4000 g or more, an OR of 2.28 (95% CI: 1.08–4.75), Ptrend<0.01. Using hospital-based controls, the OR for 4000 g or more, compared to 2500–2999 g, was 1.30 (95% CI: 1.02–1.43) after adjusting for confounders (gender, income, maternal age, pesticide and hormonal exposure during pregnancy). The results suggest that high birth weight is associated with increased risk of IL
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