Snow and Ice Roads: Ability to Support Traffic and Effects on Vegetation

A study was made of the effects of construction, and use by wheeled vehicles, of snow and ice roads at a test site near Norman Wells, N.W.T. Peat was compressed as a result of these operations. The proportion of the test roads covered by live plants was about 12% in the first summer after construction and increased to about 35% in the second summer. Land cleared of vegetation by hand was less disturbed than that cleared by machine, but machine clearing is tolerable if there is to be further disturbance. Ice-capped snow roads and ice roads, properly constructed and maintained, are shown to be capable of withstanding the traffic and loads to be expected during possible pipeline construction along the Mackenzie River Valley

Turf Wars

Turf wars commonly occur in environments where competition undermines collaboration. We develop a game theoretic model and experimental test of turf wars. The model explores how team production incentives ex post affect team formation decisions ex ante. In the game, one agent decides whether to share jurisdiction over a project with other agents. Agents with jurisdiction decide whether to exert effort and receive a reward based on their relative performance. Hence, sharing can increase joint production but introduces competition for the reward. We find that collaboration has a non-monotonic relationship with both productivity and rewards. The laboratory experiment confirms the model's main predictions. We also explore extensions of the basic model, including one where each agent's productivity is private information

Global crises and populism : the role of Eurozone institutions

Populist parties are likely to gain consensus when mainstream parties and status quo institutions fail to manage the shocks faced by their economies. Institutional constraints, which limit the possible actions in the face of shocks, result in poorer performance and frustration among voters who turn to populist movements. We rely on this logic to explain the different support of populist parties among European countries in response to the globalization shock and to the 2008-2011 financial and sovereign debt crisis. We predict a greater success of populist parties in response to these shocks in Euro zone countries, and our empirical analysis confirms this prediction. This is consistent with voters’ frustration for the greater inability of the Euro zone governments to react to difficult-to-manage globalization shocks and financial crises. Our evidence has implications for the speed of construction of political unions. A slow, staged process of political unification can expose the EU to a risk of political backlash if hard to manage shocks hit the economies during the integration process

Low mass dimuons within a hybrid approach

We analyse dilepton emission from hot and dense hadronic matter using a hybrid approach based on the Ultrarelativistic Quantum Molecular Dynamics (UrQMD) transport model with an intermediate hydrodynamic stage for the description of heavy-ion collisions at relativistic energies. Focusing on the enhancement with respect to the contribution from long-lived hadron decays after freeze-out observed at the SPS in the low mass region of the dilepton spectra (often referred to as "the excess"), the relative importance of the emission from the equilibrium and the non-equilibrium stages is discussed.Comment: Proceedings of Hot Quarks 2010, 21-26 June 2010 Las Londe Les Maures; v2: Corrected typos and added a commen

Cadmium, manganese, nickel and lead contents in surface sediments of the lower Ulla River and its estuary (northwest Spain)

The authors determined the total contents of cadmium, manganese, nickel and lead in 16 surface sediment samples along the last 7 km of the Ulla River and in its estuary. Prior to chemical analysis, the grain-size fractions below 500, 63 and 2 μm were separated. The metal concentrations were analysed in the fraction below 63 μm, and in selected samples from the clay fraction ( 2 μm). The soil samples were digested with a HF + HNO₃ + HCl mixture and the total concentrations of Cd, Mn, Ni and Pb were analysed with the AAS method. The highest contents of metals were found in the riverine sediments, near the town of Padrón, and in the estuary. The enrichment of metals in the sediments was mainly related to the proximity of the industrial sources, and to the fine particles transported and deposited in the sediments. The Ni and Mn contents found are considered very high, at some points reaching values of up to 357 mg kg⁻¹ and 2 110 mg kg⁻¹, respectively. Lead and Cd were mainly found within the range considered as natural background levels in the sediments of the Galician rias, with concentrations of 25-68 mg kg⁻¹ for Pb and 0.01-0.92 mg kg⁻¹ for Cd. The lower part of the Ulla River and its estuary present: l) moderate to high contamination levels of Mn and Ni; 2) moderate Pb pollution levels; and 3) no Cd contamination. The highest concentrations of metals were obtained in the river, near the wastewater discharges, and in the estuary, associated with fine particles.El contenido total de cadmio, manganeso, níquel y plomo se determinó en 16 muestras de sedimentos superficiales a lo largo de los últimos 7 km del río Ulla y en su estuario. Previamente a los análisis químicos, se realizó la separación granulométrica de los sedimentos en las fracciones inferiores a 500, 63 y 2 μm. La concentración de metales se determinó en la fracción inferior a 63 μm y, para algunas muestras, en la fracción arcilla ( 2 μm). La digestión del sedimento se realizó en una mezcla ácida de HF + HNO₃ + HCl y se analizó la concentración total de Cd, Mn, Ni y Pb por espectroscopia de absorción atómica. Los contenidos más altos en metales se encontraron en los sedimentos del río, en las inmediaciones de Padrón y en los del estuario. El enriquecimiento de los sedimentos en metales se ha relacionado con la proximidad a las zonas industriales y con el material fino transportado y depositado en los sedimentos. Se han encontrado contenidos muy altos de Ni y Mn con valores de 357 mg kg⁻¹ y 2 110 mg kg⁻¹, respectivamente. Las concentraciones de Cd y Pb son comparables a los valores establecidos como niveles naturales en los sedimentos de las rías gallegas: 25-68 mg kg⁻¹ para el Pb y 0.01-0.92 mg kg⁻¹ para el Cd. El sedimento de la parte baja del río Ulla y su estuario presentan niveles moderados-altos de contaminación para Mn y Ni, moderados para Pb y nulos para Cd. Las mayores concentraciones de estos metales en el sedimento fueron medidas asociadas con las fracciones finas ( 63 μm): cerca de Padrón, zona de influencia fluvial y, también, aunque con valores más bajos, en la desembocadura del Ulla, zona de influencia marina.Instituto Español de Oceanografí

Components tòxics del fum del tabac i les seves conseqüències sobre l'organisme humà

Quins són els compostos del fum del tabac? Quines són les malalties cròniques que tenen el tabac com a principal factor conductual

Positioning errors of anatomical landmarks identified by fixed vertices in homologous meshes

[EN] Background: Human movement analysis is usually achieved by tracking markers attached to anatomical landmarks with photogrammetry. Such marker-based systems have disadvantages that have led to the development of markerless procedures, although their accuracy is not usually comparable to that of manual palpation procedures. New motion acquisition systems, such as 3D temporal scanners, provide homologous meshes that can be exploited for this purpose. Research question: Can fixed vertices of a homologous mesh be used to identify anatomical landmarks with an accuracy equivalent to that of manual palpation? Methods: We used 3165 human shape scans from the CAESAR dataset, with labelled locations of anatomical landmarks. First, we fitted a template mesh to the scans, and assigned a vertex of that mesh to 53 anatomical landmarks in all subjects. Then we defined a nominal vertex for each landmark, as the more centred vertex out of the set assigned for that landmark. We calculated the errors of the template-fitting and the nominal vertex determination procedures, and analysed their relationship to subject's sex, height and body mass index, as well as their size compared to manual palpation errors. Results: The template-fitting errors were below 5 mm, and the nominal vertex determination errors reached maximum values of 24 mm. Except for the trochanter, those errors were the same order of magnitude or smaller than inter-examiner errors of lower limb landmarks. Errors increased with height and body mass index, and were smaller for men than for women of the same height and body mass index. Significance: We defined a set of vertices for 53 anatomical landmarks in a homologous mesh, which yields location errors comparable to those obtained by manual palpation for the majority of landmarks. We also quantified how the subject's sex and anthropometric features can affect the size of those errors.Activity developed within the framework of the IBERUS project. Technological Network of Biomedical Engineering applied to degenerative pathologies of the neuromusculoskeletal system in clinical outpatient settings (CER-20211003) . CERVERA Network financed the Ministry of Science and Innovation through the Centre for Industrial Technological Development (CDTI) charged to the General State Budgets 2021 and the Recovery. Transformation and Resilience Plan. Activity developed within the framework of the "IBV 2023 Non-economic Activities Plan" (IMAMCA/2023/7) , financed by the Nominative Line S8021000 distributed in favour of the technology centres of the Valencian Community, approved by the Budget Law of the Generalitat 2023.Ruescas Nicolau, AV.; De Rosario Martínez, H.; Parrilla Bernabé, E.; Juan, M. (2024). Positioning errors of anatomical landmarks identified by fixed vertices in homologous meshes. Gait & Posture. 108:215-221. https://doi.org/10.1016/j.gaitpost.2023.11.02421522110

A Deep Learning Model for Markerless Pose Estimation Based on Keypoint Augmentation: What Factors Influence Errors in Biomechanical Applications?

[EN] In biomechanics, movement is typically recorded by tracking the trajectories of anatomical landmarks previously marked using passive instrumentation, which entails several inconveniences. To overcome these disadvantages, researchers are exploring different markerless methods, such as pose estimation networks, to capture movement with equivalent accuracy to marker-based photogrammetry. However, pose estimation models usually only provide joint centers, which are incomplete data for calculating joint angles in all anatomical axes. Recently, marker augmentation models based on deep learning have emerged. These models transform pose estimation data into complete anatomical data. Building on this concept, this study presents three marker augmentation models of varying complexity that were compared to a photogrammetry system. The errors in anatomical landmark positions and the derived joint angles were calculated, and a statistical analysis of the errors was performed to identify the factors that most influence their magnitude. The proposed Transformer model improved upon the errors reported in the literature, yielding position errors of less than 1.5 cm for anatomical landmarks and 4.4 degrees for all seven movements evaluated. Anthropometric data did not influence the errors, while anatomical landmarks and movement influenced position errors, and model, rotation axis, and movement influenced joint angle errors.Research activity supported by Instituto Valenciano de Competitividad Empresarial (IVACE) and Valencian Regional Government (GVA), IMAMCA/2024; and project IMDEEA/2024, funding requested to Instituto Valenciano de Competitividad Empresarial (IVACE), call for proposals 2024, for Technology Centers of the Valencian Region, funded by European Union.Ruescas Nicolau, AV.; Medina Ripoll, E.; De Rosario Martínez, H.; Sanchiz Navarro, J.; Parrilla Bernabé, E.; Juan, M. (2024). A Deep Learning Model for Markerless Pose Estimation Based on Keypoint Augmentation: What Factors Influence Errors in Biomechanical Applications?. Sensors. 24(6). https://doi.org/10.3390/s2406192324

Dujardinascaris helicina (Nematoda: Ascarididae) parásito de Crocodylus acutus (Reptilia: Crocodylidae) en Puerto Vallarta, Jalisco, México

ResumenEl cocodrilo de río (Crocodylus acutus, Cuvier, 1807) es una especie protegida en México. En este trabajo se han estudiado los contenidos obtenidos por medio de lavados gástricos a 53C. acutus, en las áreas del estero el Salado, estero Boca Negra-Boca de Tomates y en la UMA Reptilario Cipactli, ubicadas en Puerto Vallarta, Jalisco, México, con el fin de conocer la helmintofauna de la especie. Se identificó solamente al nemátodo, Dujardinascaris helicina (Molin, 1860). La mayor prevalencia fue del 74% y la abundancia 3.17 en el área del estero Boca Negra-Boca de Tomates; y la menor prevalencia fue del 12%, con una abundancia de 0.76 en los ejemplares en la UMA Reptilario Cipactli. Suponemos que esta diferencia se debe principalmente al tipo de alimento suministrado a los cocodrilos en cautiverio. En esta investigación se registra por primera vez a D. helicina como parásito de C. acutus en la región.AbstractThe river crocodile (Crocodylus acutus, Cuvier, 1807) is a protected species in Mexico. In this work the stomach contents obtained through gastric lavage of 53 C. acutus from the estuarine systems “El Salado”, “Boca Negra-Boca de Tomates” and from the “UMA (Unidad de Manejo y Conservación de Vida Silvestre” for its meaning in Spanish) Reptilario Cipactli” located in Puerto Vallarta, Jalisco, Mexico were collected to study the helminth fauna of the species. Only Dujardinascaris helicina (Molin, 1860) was identified. The highest prevalence occurred in “Boca Negra-Boca de Tomates” with 74% and an abundance of 3.17, and the lowest in “UMA Reptilario Cipactli” with 12% and an abundance of 0.76. The dissimilarity is assumed to be caused primarily by the different feeding habits between wildlife and captivity raised crocodiles. During this investigation D. helicina is registered for the first time as a parasite for C. acutus in the region

Transverse Momentum Spectra of Pions in Particle and Nuclear Collisions and Some Ratio-Behaviours: Towards A Combinational Approach

The nature of transverse momentum dependence of the inclusive cross-sections for secondary pions produced in high energy hadronic($PP$), hadronuclear($PA$) and nuclear($AA$) collisions has here been exhaustively investigated for a varied range of interactions in a unified way with the help of a master formula. This formula evolved from a new combination of the basic Hagedorn's model for particle(pion) production in PP scattering at ISR range of energies, a phenomenological approach proposed by Peitzmann for converting the results of $NN(PP)$ reactions to those for either $PA$ or $AA$ collisions, and a specific form of parametrization for mass number-dependence of the nuclear cross sections. This grand combination of models(GCM) is then applied to analyse the assorted extensive data on various high energy collisions. The nature of qualitative agreement between measurements and calculations on both the inclusive cross-sections for production of pions, and some ratios of them as well, is quite satisfactory. The modest successes that we achieve here in dealing with the massive data-sets are somewhat encouraging in view of the diversity of the reactions and the very wide range of interaction energies.Comment: 19 pages, 19 figure