62 research outputs found
Local moisture recycling across the globe
Changes in evaporation over land affect terrestrial precipitation via atmospheric moisture recycling and, consequently, freshwater availability. Although global moisture recycling at regional and continental scales is relatively well understood, the patterns of local moisture recycling and the main variables that impact it remain unknown. We calculate the local moisture recycling ratio (LMR) as the fraction of evaporated moisture that precipitates within a distance of 0.5∘ (typically 50 km) of its source, identify variables that correlate with it over land globally, and study its model dependency. We derive the seasonal and annual LMR using a 10-year climatology (2008–2017) of monthly averaged atmospheric moisture connections at a scale of 0.5∘ obtained from a Lagrangian atmospheric moisture tracking model. We find that, annually, an average of 1.7 % (SD of 1.1 %) of evaporated moisture returns as precipitation locally, although with large temporal and spatial variability, and the LMR peaks in summer and over wet and mountainous regions. Our results show that wetness, orography, latitude, convective available potential energy, wind speed, and total cloud cover correlate clearly with the LMR, indicating that wet regions with little wind and strong ascending air are particularly favourable for a high LMR. Finally, we find that spatial patterns of local recycling are consistent between different models, yet the magnitude of recycling varies. Our results can be used to study the impacts of evaporation changes on local precipitation, with implications for, for example, regreening and water management.</p
Current driven switching of magnetic layers
The switching of magnetic layers is studied under the action of a spin
current in a ferromagnetic metal/non-magnetic metal/ferromagnetic metal spin
valve. We find that the main contribution to the switching comes from the
non-equilibrium exchange interaction between the ferromagnetic layers. This
interaction defines the magnetic configuration of the layers with minimum
energy and establishes the threshold for a critical switching current.
Depending on the direction of the critical current, the interaction changes
sign and a given magnetic configuration becomes unstable. To model the time
dependence of the switching process, we derive a set of coupled Landau-Lifshitz
equations for the ferromagnetic layers. Higher order terms in the
non-equilibrium exchange coupling allow the system to evolve to its
steady-state configuration.Comment: 8 pages, 2 figure. Submitted to Phys. Rev.
Current-Driven Magnetization Dynamics in Magnetic Multilayers
We develop a quantum analog of the classical spin-torque model for
current-driven magnetic dynamics. The current-driven magnetic excitation at
finite field becomes significantly incoherent. This excitation is described by
an effective magnetic temperature rather than a coherent precession as in the
spin-torque model. However, both the spin-torque and effective temperature
approximations give qualitatively similar switching diagrams in the
current-field coordinates, showing the need for detailed experiments to
establish the proper physical model for current-driven dynamics.Comment: 5 pages, 2 figure
Assessing knowledge and skills of maternity care professionals regarding neonatal hyperbilirubinaemia: a nationwide survey
Background: Neonatal hyperbilirubinaemia is a physiologic phenomenon, but, when severe, may cause lifelong disability. Maternity care assistants (MCAs) play an important role in timely recognition of severe neonatal jaundice. We assessed knowledge and skills of MCAs regarding neonatal hyperbilirubinaemia. Methods: All Dutch MCAs (n = 9065) were invited to fill out a questionnaire assessing knowledge, expertise, and handling of neonatal jaundice. Additionally, we developed an e-learning and provided training sessions to a subgroup of MCAs (n = 99), and assessed their knowledge on neonatal hyperbilirubinaemia before and after the training. Results: One thousand four hundred sixty-five unique online questionnaires were completed (response 16.2%). The median number of correctly answered knowledge questions was 5 (out of six; IQR 1). Knowledge was significantly better when respondents had had in-service training on neonatal hyperbilirubinaemia in the previous year (p = 0.024). Although 82% of respondents felt highly skilled or skilled to assess jaundice, accuracy of estimation of total serum bilirubin levels by assessing skin colour was generally poor and prone to underestimation. Among participants attending a training session, those who completed the e-learning beforehand had higher pre-training scores (5 (IQR 1) vs. 4 (IQR 2); p < 0.001). The median post-training score was higher than pre-training (6 (IQR 1) vs. 5 (IQR 2); p < 0.001). Conclusions: Backgroun
Magnetoresistive effects in planar NiFe nanoconstrictions
This study focuses on domain wall resistance in Ni80Fe20 nanowires containing narrow constrictions
down to 15 nm in width. Distinct differences in the magnetoresistance curves were found to depend
on the constriction size. Wider constrictions are dominated by the overall anisotropic
magnetoresistance of the structure, while constrictions narrower than ;40 nm exhibit an additional
distinct contribution from a domain wall. The effect is negative and typically varies from 1% to 5%
Ustekinumab trough concentrations are associated with biochemical outcomes in patients with Crohn's disease
Objective: It is unknown whether ustekinumab (UST) levels can predict clinical outcomes in Crohn's disease (CD) patients. We assessed the exposure-response relationship of UST trough concentrations with biochemical outcomes at week 24 in a prospective, real-world setting. Methods: We performed a prospective study in patients with CD starting UST in four academic centres in the Netherlands. All patients received a weight-adjusted intravenous (IV) UST induction dose, followed by one subcutaneous (SC) dose of 90 mg UST at 8 weeks. Maintenance therapy consisted of 90 mg subcutaneous UST every 8 or 12 weeks. Individual UST concentration time course during treatment were estimated using a population pharmacokinetic (PK) model. Quartile analysis and logistic regression were performed to analyse if UST concentrations at week 8 were associated with biochemical remission rates at week 24 (C-reactive protein (CRP) = 6.3 mu g/mL at week 8) had higher biochemical remission rates at week 12 and week 24. There was no association between UST levels at and corticosteroid-free clinical remission rates .Conclusion: In this real-world cohort of patients with CD, UST levels in the highest quartile (>= 6.3 mu g/mL) at week 8 were associated with higher biochemical remission rates at week 24.Cellular mechanisms in basic and clinical gastroenterology and hepatolog
Mechanomyographic amplitude and frequency responses during dynamic muscle actions: a comprehensive review
The purpose of this review is to examine the literature that has investigated mechanomyographic (MMG) amplitude and frequency responses during dynamic muscle actions. To date, the majority of MMG research has focused on isometric muscle actions. Recent studies, however, have examined the MMG time and/or frequency domain responses during various types of dynamic activities, including dynamic constant external resistance (DCER) and isokinetic muscle actions, as well as cycle ergometry. Despite the potential influences of factors such as changes in muscle length and the thickness of the tissue between the muscle and the MMG sensor, there is convincing evidence that during dynamic muscle actions, the MMG signal provides valid information regarding muscle function. This argument is supported by consistencies in the MMG literature, such as the close relationship between MMG amplitude and power output and a linear increase in MMG amplitude with concentric torque production. There are still many issues, however, that have yet to be resolved, and the literature base for MMG during both dynamic and isometric muscle actions is far from complete. Thus, it is important to investigate the unique applications of MMG amplitude and frequency responses with different experimental designs/methodologies to continually reassess the uses/limitations of MMG
Neural network analysis for prediction of treatment outcome in ovarian cancer
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