Influence of different wind directions in relation to topography on the outbreak of convection in Northern England

International audienceThe influence of different wind directions on the outbreak of convection in Northern England, was investigated with a high-resolution numerical model. The Clark model, a 3D finite-difference, non-hydrostatic model was used in this study. It was initialised with the topography of Northern England, a representation of surface characteristics, and used a routinely available meteorological sounding, typical of the unstable conditions. Results showed that convective cells were initially triggered in the lee of the elevated terrain, and that only after the convection had developed, were cells upwind of the elevated terrain produced. The windward slopes themselves seemed sheltered from convection. Under most wind directions, the central Pennines (the Forest of Trawden and the Forest of Rossendale) seemed particularly affected by convective rainfall

期外収縮後一過性収縮性増強の減衰過程を指数関数でカーブフィッティングすると心筋細胞内のカルシウム再循環率を過小評価する可能性がある：理論的・数学的解析

Marine cloud brightening (MCB) is one of several proposed solar radiation management (SRM) geoengineering schemes designed to ameliorate some of the undesirable effects of climate change, for example polar ice loss and associated increased sea levels. Satellite measurements over the last 40 years show a general reduction in polar sea ice area and thickness which is attributed to climate change. In our studies, HadGEM1, a fully coupled climate model, is used to predict changes in surface temperatures and ice cover as a result of implementing MCB in a double carbon dioxide concentration atmosphere. The meridional heat flux (MHF) is the mechanism within the earth system for the transport of energy from tropical to polar regions. This poleward transport of heat in a double carbon dioxide atmosphere amplifies the effects in polar regions, where it has a significant impact on both temperatures and ice cover. The results from this work show that MCB is capable of roughly restoring control temperatures and ice cover (where control is defined as 440 ppm carbon dioxide, a predicted 2020 level) in a double carbon dioxide atmosphere scenario. This work presents the first results on the impact of MCB on the MHF and the ability of the MCB scheme to restore the MHF to a control level

Common and unique neural activations in autobiographical, episodic, and semantic retrieval

This study sought to explore the neural correlates that underlie autobiographical, episodic, and semantic memory. Autobiographical memory was defined as the conscious recollection of personally relevant events, episodic memory as the recall of stimuli presented in the laboratory, and semantic memory as the retrieval of factual information and general knowledge about the world. Our objective was to delineate common neural activations, reflecting a functional overlap, and unique neural activations, reflecting functional dissociation of these memory processes. We conducted an event-related functional magnetic resonance imaging study in which we utilized the same pictorial stimuli but manipulated retrieval demands to extract autobiographical, episodic, or semantic memories. The results show a functional overlap of the three types of memory retrieval in the inferior frontal gyrus, the middle frontal gyrus, the caudate nucleus, the thalamus, and the lingual gyrus. All memory conditions yielded activation of the left medial-temporal lobe; however, we found a functional dissociation within this region. The anterior and superior areas were active in episodic and semantic retrieval, whereas more posterior and inferior areas were active in autobiographical retrieval. Unique activations for each memory type were also delineated, including medial frontal increases for autobiographical, right middle frontal increases for episodic, and right inferior temporal increases for semantic retrieval. These findings suggest a common neural network underlying all declarative memory retrieval, as well as unique neural contributions reflecting the specific properties of retrieved memories

Radiation and dynamics of the atmosphere of Mars

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Low-field thermal mixing in [1-13C] pyruvic acid for brute-force hyperpolarization

We detail the process of low-field thermal mixing (LFTM) between 1H and 13C nuclei in neat [1-13C] pyruvic acid at cryogenic temperatures (4–15 K). Using fast-field-cycling NMR, 1H nuclei in the molecule were polarized at modest high field (2 T) and then equilibrated with 13C nuclei by fast cycling (∼300–400 ms) to a low field (0–300 G) that activates thermal mixing. The 13C NMR spectrum was recorded after fast cycling back to 2 T. The 13C signal derives from 1H polarization via LFTM, in which the polarized (‘cold’) proton bath contacts the unpolarised (‘hot’) 13C bath at a field so low that Zeeman and dipolar interactions are similar-sized and fluctuations in the latter drive 1H–13C equilibration. By varying mixing time (tmix) and field (Bmix), we determined field-dependent rates of polarization transfer (1/τ) and decay (1/T1m) during mixing. This defines conditions for effective mixing, as utilized in ‘brute-force’ hyperpolarization of low-γ nuclei like 13C using Boltzmann polarization from nearby protons. For neat pyruvic acid, near-optimum mixing occurs for tmix ∼ 100–300 ms and Bmix ∼ 30–60 G. Three forms of frozen neat pyruvic acid were tested: two glassy samples, (one well-deoxygenated, the other O2-exposed) and one sample pre-treated by annealing (also well-deoxygenated). Both annealing and the presence of O2 are known to dramatically alter high-field longitudinal relaxation (T1) of 1H and 13C (up to 102–103-fold effects). Here, we found smaller, but still critical factors of ∼(2–5)× on both τ and T1m. Annealed, well-deoxygenated samples exhibit the longest time constants, e.g., τ ∼ 30–70 ms and T1m ∼ 1–20 s, each growing vs. Bmix. Mixing ‘turns off’ for Bmix > ∼100 G. That T1m ≫ τ is consistent with earlier success with polarization transfer from 1H to 13C by LFTM

Use of nuclear spin noise spectroscopy to monitor slow magnetization buildup at millikelvin temperatures

At ultralow temperatures, longitudinal nuclear magnetic relaxation times become exceedingly long and spectral lines are very broad. These facts pose particular challenges for the measurement of NMR spectra and spin relaxation phenomena. Nuclear spin noise spectroscopy is used to monitor proton spin polarization buildup to thermal equilibrium of a mixture of glycerol, water, and copper oxide nanoparticles at 17.5 mK in a static magnetic field of 2.5 T. Relaxation times determined in such a way are essentially free from perturbations caused by excitation radiofrequency pulses, radiation damping, and insufficient excitation bandwidth. The experimental spin-lattice relaxation times determined on resonance by saturation recovery with spin noise detection are consistently longer than those determined by using pulse excitation. These longer values are in better accordance with the expected field dependence trend than those obtained by on-resonance experiments with pulsed excitation

The representation of Föhn events to the east of the Antarctic Peninsula in simulations by the Antarctic Mesoscale Prediction System (AMPS)

Föhn winds are warm, strong, downslope winds on the lee side of mountains, which can last from several hours to a few days. 1995 and 2002 saw the dramatic break‐up of huge parts of the Larsen Ice Shelf (LIS) on the east of the Antarctic Peninsula (AP). It is widely accepted that hydrofracturing, the widening of crevasses due to the excess hydrostatic pressure exerted by meltwater which accumulates inside them, is the mechanism behind the break‐up of the Larsen A and Larsen B ice shelves. On the LIS, in the lee of the mountain range that runs along the spine of the AP, Föhn winds are thought to provide the atmospheric conditions for significant warming over the ice shelf, leading to the initial firn densification, and subsequently providing the melt water for hydrofracturing. Measurements provide evidence that in some cases Föhn events reach an Automatic Weather Station (AWS) on the LIS at over 100 km distance. In this paper, we examine the representation of Föhn events during 2011 as they were observed in measurements by an AWS, and in simulations with the Weather Research and Forecasting Model (WRF) as run for the Antarctic Mesoscale Prediction System (AMPS). We find that, while the model generally simulates meteorological parameters very well, and shows good skill in capturing the occurrence, frequency and duration of Föhn events, it underestimates the temperature increase and humidity decrease during the Föhn significantly, and may thus underestimate the contribution of Föhn to driving surface melt on LIS

Maintaining Quality of Education in the Graduate School Education - Reforms Required

Graduate school education serves as a vital platform for advanced learning, research, and professional development. However, the dynamic landscape of higher education, characterized by shifting economic, technological, and societal paradigms, has prompted a critical examination of the methods and quality of graduate education. In light of these challenges, this study explores the imperatives and pathways for maintaining and enhancing the quality of education in graduate schools. A mixed-method research design was employed, encompassing both quantitative and qualitative data collection techniques. Surveys were administered to educators, policymakers, and administrators in graduate education, while in-depth interviews and focus group discussions were conducted to gain nuanced insights. The study adopted the Theory of Planned Behavior as a conceptual framework to assess attitudes, subjective norms, and perceived behavioral control in relation to educational reforms. Quantitative analysis revealed widespread positive attitudes toward educational reforms among participants. Subjective norms, reflecting the influence of colleagues and stakeholders, played a pivotal role in shaping intentions to support and initiate reforms. Additionally, perceived behavioral control emerged as a significant determinant of reform-oriented intentions. Challenges, such as resource constraints and resistance to change, were identified as barriers to reform implementation. Qualitative insights underscored the importance of resource allocation, faculty development, and curriculum flexibility in successful reform efforts. Furthermore, globalization and internationalization were recognized as drivers of change, emphasizing the need for cross-cultural education and global collaborations. The study recommends a multifaceted approach to educational reform in graduate schools, including investments in faculty development, promotion of flexible curriculum design, strategies to address resistance to change, and efforts to embrace global and cross-cultural education. This study underscores the imperative of maintaining and enhancing the quality of graduate education through well-informed reforms. By addressing challenges and capitalizing on positive attitudes and social support, institutions can adapt effectively to changing educational paradigms and continue to provide high-quality graduate education that prepares students for the demands of the future

A case study investigation of summer temperature conditions at two coastal sites in the UK, and analysis of future temperatures and heat wave structures in a warming climate scenario

Using observations for two UK coastal sites <3 km from the sea, one on the West coast near the nuclear new build (NNB) site Hinkley Point C (HPC) and the other on the East coast, near the proposed NNB site Bradwell B (BRB), changes in surface two-metre temperatures are analysed. The output from a numerical model (WRF) experiment is used for a control period, 1990-1995, [Gadian et al. 2018] and for the period 2031-2036. The nested convective permitting model at a resolution of O(3km) is driven by a global channel model at a resolution of O(20km), enabling a more detailed comparison on the weather scale than is available with current climate models. Further, using the RCP8.5 warming scenario, the results are analysed. In the future scenario, there is an increase in the number of days where the summer (JJA) model temperatures exceed 25{\deg}C. There is a future warming of 1.2{\deg}C (BRB) and 1.1{\deg}C (HPC) in the mean JJA maximum daily temperatures compared with the control values and an average annual maximum daily temperature warming of 1.2{\deg}C (BRB) and 0.5{\deg}C (HPC). For the control period, the model under-predicts both the maximum and particularly the minimum temperatures. Results indicate there will be a >25% increase in the number of summer days when the maximum temperature exceeds 25{\deg}C, a 60% increase when the temperature exceeds the minimum of 13{\deg}C, (Tables 3, 4) and an increase in heat wave events per annum of greater than 10 days, [Gadian et al. 2018]. The increases in summer temperatures are larger than those predicted in the 2013 IPCC assessment [Collins et al 2013], but consistent with the maximum temperatures and increased number of hot days listed in UKCP18 [Met Office 2019(b)]. The higher resolution model results suggest that the IPCC report underestimates the increases in maximum temperatures at these locations.Comment: 24 Pages, 4 Figures, 4 Table