Campsite impacts in protected natural areas are most effectively minimized by a containment strategy that focuses use on a limited number of sustainable campsites that spatially concentrate camping ...activities. This research employs spatial autoregressive (SAR) modeling to evaluate the relative influence of use-related, environmental, and managerial factors on two salient measures of campsite impact. Relational analyses examined numerous field-collected and GIS-derived indicators, including several new indicators calculated using high-resolution Light Detection and Ranging (LiDAR) topographic data to evaluate the influence of terrain characteristics on the dependent variables.
Chosen variables in the best SAR models explained 35% and 30% of the variation in campsite size and area of vegetation loss on campsites. Results identified three key indicators that managers can manipulate to enhance the sustainability of campsites: campsite type, and terrain characteristics relating to landform slope and topographic roughness. Results support indirect management methods that rely on the location, design, construction, and maintenance of campsites, instead of direct regulations that restrict visitation or visitor freedoms. As visitation pressures continue to increase, this knowledge can be applied to select and promote the use of more ecologically sustainable campsites.
•Campsite size can be constrained by steep offsite slopes.•Campsite size can be minimized by side-hill campsite construction.•Sunny grassy campsites lose the least vegetation cover.
The reduced activation ferritic martensitic steel EUROFER is one of the foreseen structural materials for future fusion reactors. The exposure to energetic fusion neutrons will generate displacement ...damage in the steel which acts as trapping sites for hydrogen isotopes (HIs). For predictive simulations of HI retention the concentration of the trap sites and HI trap-binding energies are needed. In this work the potential influence of HIs present during displacement damage on the resulting trap site concentration is investigated. EUROFER samples are exposed to multiple sequences of displacement damage by MeV W-ions and subsequent loading by D-ions from a low temperature plasma. After each of these damage/loading sequences the D depth profile in the surfaces is measured by nuclear reaction analysis (NRA) using a 3He beam. These depth profiles show a clear increase in the trap site concentration when the displacement damaging step is performed on a sample already containing trapped D. The presence of 3He in analysis spots from previous NRA-depth profiling also results in a strong increase of local retention due to traps formed by the implanted 3He. Thermal desorption spectra show that in EUROFER retention is dominated by the bulk, even in the presence of displacement damage in the near surface. These results suggest that the presence of D and He in EUROFER will result in increased retention compared to pure EUROFER under displacement damage.
•First investigation of influence of hydrogen on displacement damage in EUROFER.•Presence of hydrogen during displacement damage increased hydrogen trap site density.•Pre-implantation with He increases retention via new trap types.
•Tritium losses in the DEMO first wall were investigated with T gas and ion loading.•Code comparison with TMAP and TESSIM showed good agreement in a DEMO-like scenario.•Hundreds of g of T may be ...retained in wall. Up to 160 mg T could permeate per day.•With bare EUROFER wall, retention below 100 g but T permeation up to several g/day.•Impact of T losses on T fuel cycle assessed with simplified particle balance model.
Tritium self-sufficiency presents a critical engineering challenge for DEMO, requiring efficient breeding and extraction systems, as well as minimizing tritium losses to the surrounding systems, such as plasma-facing components, vacuum vessel, cooling system, etc. Structural and plasma-facing components will act as a tritium sink, as tritium will be accumulated in the bulk of these components due to energetic particle bombardment and may permeate out of the vacuum system. The design of the plasma-facing components will consequently directly influence the plant lifetime, operational safety and cost of any future power plant. Therefore, modeling of tritium retention and permeation in these components is required for the engineering designs of the tritium breeding and safety systems. In this work, the diffusion-transport code TESSIM-X is benchmarked against the well-established TMAP7 code and a comparison with a simplified DEMO-relevant test case is performed. The use of either code for modeling of DEMO conditions is discussed. Following this, TESSIM-X is used to provide a preliminary assessment of tritium permeation and retention in the DEMO first wall, based on the current WCLL (Water Cooled Lithium Lead) and HCPB (Helium Cooled Pebble Bed) breeding blanket designs.
In recent years, machine and deep learning models have attracted significant attention for electricity price forecast in global wholesale electricity markets. Yet, a predominant focus on point ...forecast in most parts of literature limits the practical application of these models due to the absence of uncertainty quantification. In this study, we first perform an analysis of the electricity price trends in the Mexican wholesale electricity market to determine the influence of key variables. Using independent component analysis and wavelet coherence analysis, we were able to identify primary determinants influencing locational marginal electricity prices. Subsequently, we applied four different models covering the most important algorithms proposed in the literature for electricity price forecast. Our findings revealed that the most accurate forecasting results were achieved using a deep learning‐based method with a decision tree‐based model trailing closely. Finally, we incorporate conformal prediction for uncertainty quantification by calculating the prediction intervals with a target coverage level of 95%. The conformal prediction intervals provide a more comprehensive view of the possible future scenarios, enhancing economic efficiency, risk management, and decision‐making processes. This is particularly important because of the dynamic nature of electricity markets, where prices are strongly influenced by multiple factors.
This study demonstrates the potential of using hybrid models for electricity price forecasting The findings suggest that natural gas prices would be sufficient for electricity price forecast in the Mexican market resulting in a simple model for deployment thus significantly reducing the computational costs. LSTM‐based and decision tree‐based models outperformed the ‘classical’ models in terms of accuracy and uncertaninty. This research offers significant insights for policymakers, energy traders, the academic community, and other key stakeholders, enhancing their understanding of the impact of exogenous variables on electricity prices. Finally, we incorporate conformal prediction for uncertainty quantification by calculating the predication intervals with a target coverage level of 95%.
Hospital payments depend on the Medicare Severity Diagnosis-Related Group’s estimated cost and the set of diagnoses identified during inpatient stays. However, over-coding and under-coding diagnoses ...can occur for different reasons, leading to financial and clinical consequences. We provide a novel approach to measure diagnostic coding intensity, built on commonly available administrative claims data, and demonstrated through a 2019 pneumonia acute inpatient cohort (N = 182,666). A Poisson additive model (PAM) is proposed to model risk-adjusted additional coded diagnoses. Excess coding intensity per patient visit was estimated as the difference between the observed and PAM-based expected counts of secondary diagnoses upon risk adjustment by patient-level characteristics. Incidence rate ratios were extracted for patient-level characteristics and further adjustments were explored by facility-level characteristics to account for facility and geographical differences. Facility-level factors contribute substantially to explain the remaining variability in excess diagnostic coding, even upon adjusting for patient-level risk factors. This approach can provide hospitals and stakeholders with a tool to identify outlying facilities that may experience substantial differences in processes and procedures compared to peers or general industry standards. The approach does not rely on the availability of clinical information or disease-specific markers, is generalizable to other patient cohorts, and can be expanded to use other sources of information, when available.
Currently, for the EU DEMO, two Breeding Blankets (BBs) have been selected as potential candidates for the integration in the reactor. They are the Water Cooled Lithium Lead and the Helium Cooled ...Pebble Bed BB concepts. The two BB variants together with the associated ancillary systems drive the design of the overall plant. Therefore, a holistic investigation of integration issues derived by the BB and the installation of its ancillary systems has been performed. The issues related to the water activation due to the 16N and 17N isotopes and the impact on the primary heat transfer systems have been investigated providing guidelines and dedicated solution for the integration of safety devices as isolation valves. The tritium retention and the permeation rates through the blanket and its ancillary systems have been also assessed taking into account different operating points both for the BB and ancillaries and comparing, when possible, the releases with the operating and safety limits. Moreover, the issues related to the tritium start-up inventory as well as the uncertainties on the Tritium Breeding Ratio (TBR) due to the integration of the auxiliary systems within the Vacuum Vessel have been also studied. Finally, the impact of the BB concepts on the safety systems like the Vacuum Vessel Pressure Suppression System is described with a particular focus on the different measures that should be implemented according to the considered concept. All these aspects are then taken into account to drive future developments during the Concept Design Phase.
•T inventory in the ITER EU Water-Cooled Lithium-Lead Test Blanket Module investigated.•T from vacuum vessel (gas, neutrals) and solute T in PbLi included in modeling.•Effect of neutron damaging on ...trap concentrations included in models.•T retention in the range of 0.75 g is expected over plasma operation period.•Comparison with the TMAP7 code performed.
Tritium self-sufficiency is a key requirement for future fusion power plants. Therefore, it will be necessary to minimize tritium losses to the surrounding systems, such as the tritium breeding modules, plasma-facing components, cooling system, etc. These components and systems will act also as a tritium sink, as tritium will be retained in the metal walls in traps produced during manufacturing or induced by neutron irradiation. The design of the tritium breeding systems and plasma-facing components will therefore have a direct impact on the performance, operational safety and cost of any future power plant. Consequently, accurate modeling of tritium transport and retention in these systems is needed for future engineering designs of the tritium breeding systems and supporting safety requirements. In this work, tritium permeation and retention was modeled with the diffusion-transport code TESSIM-X for the current European WCLL (Water Cooled Lithium Lead) Test Blanket Module (TBM) for the ITER TBM Programme, with the inclusion of neutron-induced traps. Trap saturation is considered for dpa values of 0.25 and above, leading to an increase in trap concentrations relative to undamaged material of roughly a factor 3. The code was also benchmarked against the well-established TMAP7 code.
Mutations in the SCN1A gene can result in syndromes associated with epilepsy, including the Dravet syndrome (DS). However, the prevalence of such mutations in these diseases varies widely between ...different studies, and has not been examined in Mexican patients with epilepsy. Therefore, the objective of this study was to determine the frequency of SCN1A mutations (in the exon 26) in a cohort of Mexican patients with DS and refractory epilepsy (RE). We recruited 24 Mexican patients (14 males and 10 females), of which 15 were diagnosed with RE and 9 were diagnosed with DS. The SCN1A gene was sequenced to uncover mutations in exon 26. We detected 2 novel genotypes in 2 DS patients. One was a synonymous variant, c.5418 G > A (E1806E), and the other was a missense variant, c. 5324 T > C (L1775P). The missense mutation was predicted to be damaging with a score of 100% by the PolyPhen-2 program. The frequency of pathogenic variants was 4.17% in all the patients and 11.1% in DS patients, which, together with other publications, emphasize that specific and more severe phenotypes are associated with SCN1A mutations.
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