Experiments on Steady-State Nonisothermal Moisture Movement in Wood

The study was conducted to measure experimentally the steady-state uniaxial (tangential direction) moisture content and temperature profiles in moisture-sealed wood samples whose opposite faces were subjected to constant but different temperatures, and to compare these profiles with those predicted by several theoretical models. The experimental variables considered were wood species, initial moisture content, and temperature range.Opposite faces of the moisture-sealed assembly were exposed continuously for approximately five weeks to different but constant temperatures until the original uniform moisture content redistributed itself. At the steady state, a moisture content gradient opposite to the temperature gradient was established. The temperature gradient was constant in all cases, with the moisture content profile increasing almost exponentially with decreasing temperature. The absolute value of the ratio of the moisture content gradient to the temperature gradient (dM/dT)s was found to increase with wood moisture content and was observed to be higher at the higher temperature range. There was only a small difference in the -(dM/dT)s between the two species studied.The ratio -(dM/dT)s was analyzed in terms of five different theoretical models, two of which are based on nonequilibrium thermodynamics (NET) and three on classical thermodynamics. The two NET models (basic NET and Nelson models) provided the best agreement with the experimental values. The Siau model gave the next best prediction, followed by the Stanish model, and lastly by the Skaar-Siau model

Multi-component avalanches for rock- and ice-falls to potential debris flow transition modelling

Rock/ice avalanches are complex gravitational flows involving three important physicalprocesses: entrainment, phase-changes, and flow transitions. The basic complexity of modelling rock/ice avalanches lies in the fact that the flow is a mixture of rock, ice, water, snow, soil sediments. The interaction of these components can lead to flow transitions which is difficult to model with simplified flow rheologies. For example, a flow initially composed of rocks and ice can transition into a long-runout debris flow, dependent on the entrainment of water, water-saturated sediments and/or snow. The dynamic behaviour of rock/ice avalanches is therefore highly difficult to predict because the flow mixture is dependent on the hydrological and geomorphological properties along the avalanche track. These properties can vary from year to year but even from season to season. The problem is intensified by the fact that frictional shearing can produce enough heat energy to melt ice and snow, leading to additional water in the flow. In this contribution, we present a new RAMMS module specifically designed to simulate single- and multicomponent avalanches of rock, ice, water, snow, and ice. The rheology of the flow is treated by using the concept of component activation energy. The model includes both snow and sediment/water/ice entrainment modules. A unique feature of the model is that it tracks the temperature of the rock, ice and water phases and therefore can treat phase changes. We apply the model on the Chamoli case-study to highlight the potential and present limitations of the model.

Insights into Rock-Ice Avalanche Dynamics by Combined Analysis of Seismic Recordings and a Numerical Avalanche Mode

Rock‐ice avalanches larger than 1 × 106 m3 are high‐magnitude, low‐frequency events that may occur in all ice‐covered, high mountain areas around the world and can cause extensive damage if they reach populated regions. The temporal and spatial evolution of the seismic signature from two events was analyzed, and recordings at selected stations were compared to numerical model results of avalanche propagation. The first event is a rock‐ice avalanche from Iliamna volcano in Alaska which serves as a “natural laboratory” with simple geometric conditions. The second one originated on Aoraki/Mt. Cook, New Zealand Southern Alps, and is characterized by a much more complex topography. A dynamic numerical model was used to calculate total avalanche momentum, total kinetic energy, and total frictional work rate, among other parameters. These three parameters correlate with characteristics of the seismic signature such as duration and signal envelopes, while other parameters such as flow depths, flow path and deposition geometry are well in agreement with observations. The total frictional work rate shows the best correlation with the absolute seismic amplitude, suggesting that it may be used as an independent model evaluation criterion and in certain cases as model calibration parameter. The good fit is likely because the total frictional work rate represents the avalanche ’s energy loss rate, part of which is captured by the seismometer. Deviations between corresponding calculated and measured parameters result from site and path effects which affect the recorded seismic signal or indicate deficiencies of the numerical model. The seismic recordings contain additional information about when an avalanche reaches changes in topography along the runout path and enable more accurate velocity calculations. The new concept of direct comparison of seismic and avalanche modeling data helps to constrain the numerical model input parameters and to improve the understanding of (rock‐ice) avalanche dynamics

Modeling deadwood for rockfall mitigation assessments in windthrow areas

Studying how deadwood mitigates the rockfall hazard in mountain forests is key to understanding the influence of climate-induced disturbances on the protective capacity of mountain forests. Both experimental quantification and numerical process modeling are needed to address this question. Modeling provides detailed insights into the rock–deadwood interaction and can therefore be used to develop effective forest management strategies. Here, we introduce an automatic deadwood generator (ADG) for assessing the impact of fresh woody storm debris on the protective capacity of a forest stand against rockfall. The creation of various deadwood scenarios allows us to directly quantify the mitigation potential of deadwood. To demonstrate the functionality of the proposed ADG method, we compare deadwood log patterns, deadwood effective height, and mesoscale surface ruggedness observed in field surveys in a natural windthrow area with their simulated counterparts. Specifically, we consider two sites near Lake Klöntal, Switzerland, where a major windthrow event occurred in 2019. We perform rockfall simulations for the time (a) before, (b) directly after, and (c) 10 years after the windthrow event. We further compare the results with (d) a simulation with complete clearing of the thrown wood: in other words, a scenario with no standing forest remaining. We showcase an integration of deadwood into rockfall simulations with realistic deadwood configurations alongside a diameter at breast height (DBH)- and rot-fungi-dependent maximum deadwood breaking energy. Our results confirm the mitigation effect of deadwood, which significantly reduces the jump heights and velocities of 400 kg rocks. Our modeling results suggest that, even a decade after the windthrow event, deadwood has a stronger protective effect against rockfall than that provided by standing trees. We conclude that an ADG can contribute to the decision-making involved in forest and deadwood management after disturbances.</p

Entrainment maps considering hydrological conditions for mass movement runout modelling: Application to debris-flow bulking at Pizzo Cengalo

Debris flows entrain sediments and water along their flow path and grow significantly in size. Because the entrainment process isn’t well understood and data is rare, hazard and risk assessment with numerical models is challenging. It is known, however, that both for debris flows and rock avalanches, interstitial pore water in flow path substrate can cause increases in pore water pressures when overridden by the flow, which enhances erosion. The entrained water likely also plays a role in the process transition from rock avalanche to debris flow, like in the Pizzo Cengalo event in 2017. We present a framework for producing entrainment maps serving as an input for runout modelling, here illustrated using RAMMS. The entrainment maps consist of spatially-distributed entities with properties such as max erosion depth, and soil water content inferred from land cover and lithology maps. This study serves as a basis for producing duration curves of subsurface water available for entrainment and include it into the entrainment maps. Such hydrologically-informed entrainment maps will be useful to assess the probability of certain runout distances

Impact of indoor residual spraying with pirimiphos-methyl (Actellic 300CS) on entomological indicators of transmission and malaria case burden in Migori County, western Kenya

Indoor residual spraying (IRS) of insecticides is a major vector control strategy for malaria prevention. We evaluated the impact of a single round of IRS with the organophosphate, pirimiphos-methyl (Actellic 300CS), on entomological and parasitological parameters of malaria in Migori County, western Kenya in 2017, in an area where primary vectors are resistant to pyrethroids but susceptible to the IRS compound. Entomological monitoring was conducted by indoor CDC light trap, pyrethrum spray catches (PSC) and human landing collection (HLC) before and after IRS. The residual effect of the insecticide was assessed monthly by exposing susceptible An. gambiae s.s. Kisumu strain to sprayed surfaces in cone assays and measuring mortality at 24 hours. Malaria case burden data were extracted from laboratory records of four health facilities within the sprayed area and two adjacent unsprayed areas. IRS was associated with reductions in An. funestus numbers in the intervention areas compared to non-intervention areas by 88% with light traps (risk ratio [RR] 0.12, 95% CI 0.07–0.21, p < 0.001) and 93% with PSC collections (RR = 0.07, 0.03–0.17, p < 0.001). The corresponding reductions in the numbers of An. arabiensis collected by PSC were 69% in the intervention compared to the non-intervention areas (RR = 0.31, 0.14–0.68, p = 0.006), but there was no significant difference with light traps (RR = 0.45, 0.21–0.96, p = 0.05). Before IRS, An. funestus accounted for over 80% of Anopheles mosquitoes collected by light trap and PSC in all sites. After IRS, An. arabiensis accounted for 86% of Anopheles collected by PSC and 66% by CDC light trap in the sprayed sites while the proportion in non-intervention sites remained unchanged. No sporozoite infections were detected in intervention areas after IRS and biting rates by An. funestus were reduced to near zero. Anopheles funestus and An. arabiensis were fully susceptible to pirimiphos-methyl and resistant to pyrethroids. The residual effect of Actellic 300CS lasted ten months on mud and concrete walls. Malaria case counts among febrile patients within IRS areas was lower post- compared to pre-IRS by 44%, 65% and 47% in Rongo, Uriri and Nyatike health facilities respectively. A single application of IRS with Actellic 300CS in Migori County provided ten months protection and resulted in the near elimination of the primary malaria vector An. funestus and a corresponding reduction of malaria case count among out-patients. The impact was less on An. arabiensis, most likely due to their exophilic nature

Neopterin and procalcitonin are suitable biomarkers for exclusion of severe Plasmodium falciparum disease at the initial clinical assessment of travellers with imported malaria

Background. Most clinicians in developed, non-malaria endemic countries have limited or no experience in making clinical assessments of malaria disease severity and subsequent decisions regarding the need for parenteral therapy or high-level monitoring in febrile patients with imported malaria. In the present study, the diagnostic accuracy of plasma soluble Triggering Receptor Expressed on Myeloid cells 1 (TREM-1), neopterin and procalcitonin levels as biomarkers for severe Plasmodium falciparum disease was evaluated in 104 travellers with imported malaria (26 patients with non-P. falciparum malaria, 64 patients with uncomplicated P. falciparum malaria and 14 patients with severe P. falciparum malaria). Methods. TREM-1, neopterin and procalcitonin were determined in serum using commercially available ELISA or EIA tests. The diagnostic performance of these biomarkers for severe disease was compared with plasma lactate, a well-validated parameter for disease severity in patients with malaria, as reference. Severe malaria was defined according to the modified WHO criteria. Results. No significant differences in TREM-1 levels were detected between the different patient groups. Patients with severe P. falciparum malaria had significantly higher neopterin and procalcitonin levels on admission when compared to patients with uncomplicated P. falciparum malaria or non-P. falciparum malaria. Receiver Operating Characteristic (ROC) curve analysis showed that neopterin had the highest Area-Under-the-ROC curve (AUROC 0.85) compared with plasma lactate (AUROC 0.80) and procalcitonin (AUROC 0.78). At a cut-off point of 10.0 ng/ml, neopterin had a positive and negative predictive value of 0.38 and 0.98 whereas procalcitonin, at a cut-off point of 0.9 ng/ml, had a positive and negative predictive value of 0.30 and 1.00. Conclusion. Although the diagnostic value of neopterin and procalcitonin is limited, the high negative predictive value of both neopterin and procalcitonin may be helpful for a rapid exclusion of severe malaria disease on admission. This may be a valuable tool for physicians only occasionally dealing with ill-returned travellers from malaria-endemic regions and who need to decide on subsequent oral anti-malarial treatment or timely referral to a specialized centre for high-level monitoring and intensified parenteral treatment

Paracrine effects of embryo-derived FGF4 and BMP4 during pig trophoblast elongation

The crosstalk between the epiblast and the trophoblast is critical in supporting the early stages of conceptus development. FGF4 and BMP4 are inductive signals that participate in the communication between the epiblast and the extraembryonic ectoderm (ExE) of the developing mouse embryo. Importantly, however, it is unknown whether a similar crosstalk operates in species that lack a discernible ExE and develop a mammotypical embryonic disc (ED). Here we investigated the crosstalk between the epiblast and the trophectoderm (TE) during pig embryo elongation. FGF4 ligand and FGFR2 were detected primarily on the plasma membrane of TE cells of peri-elongation embryos. The binding of this growth factor to its receptor triggered a signal transduction response evidenced by an increase in phosphorylated MAPK/ERK. Particular enrichment was detected in the periphery of the ED in early ovoid embryos, indicating that active FGF signalling was operating during this stage. Gene expression analysis shows that CDX2 and ELF5, two genes expressed in the mouse ExE, are only co-expressed in the Rauber's layer, but not in the pig mural TE. Interestingly, these genes were detected in the nascent mesoderm of early gastrulating embryos. Analysis of BMP4 expression by in situ hybridisation shows that this growth factor is produced by nascent mesoderm cells. A functional test in differentiating epiblast shows that CDX2 and ELF5 are activated in response to BMP4. Furthermore, the effects of BMP4 were also demonstrated in the neighbouring TE cells, as demonstrated by an increase in phosphorylated SMAD1/5/8. These results show that BMP4 produced in the extraembryonic mesoderm is directly influencing the SMAD response in the TE of elongating embryos. These results demonstrate that paracrine signals from the embryo, represented by FGF4 and BMP4, induce a response in the TE prior to the extensive elongation. The study also confirms that expression of CDX2 and ELF5 is not conserved in the mural TE, indicating that although the signals that coordinate conceptus growth are similar between rodents and pigs, the gene regulatory network of the trophoblast lineage is not conserved in these species

Exploratory study of plasma total homocysteine and its relationship to short-term outcome in acute ischaemic stroke in Nigerians

<p>Abstract</p> <p>Background</p> <p>Hyperhomocysteinemia is a potentially modifiable risk factor for stroke, and may have a negative impact on the course of ischaemic stroke. The role of hyperhomocysteinemia as it relates to stroke in Africans is still uncertain. The objective of this study was to determine the prevalence and short-term impact of hyperhomocysteinemia in Nigerians with acute ischaemic stroke. We hypothesized that Hcy levels are significantly higher than in normal controls, worsen stroke severity, and increase short-term case fatality rates following acute ischaemic stroke.</p> <p>Methods</p> <p>The study employed both a case-control and prospective follow-up design to study hospitalized adults with first – ever acute ischaemic stroke presenting within 48 hours of onset. Clinical histories, neurological evaluation (including National Institutes of Health Stroke Scale (NIHSS) scores on admission) were documented. Total plasma Hcy was determined on fasting samples drawn from controls and stroke cases (within 24 hours of hospitalization). Outcome at 4 weeks was assessed in stroke patients using the Glasgow Outcome Scale (GOS).</p> <p>Results</p> <p>We evaluated 155 persons (69 acute ischaemic stroke and 86 healthy controls). The mean age ± SD of the cases was 58.8 ± 9.8 years, comparable to that of controls which was 58.3 ± 9.9 years (T = 0.32; P = 0.75). The mean duration of stroke (SD) prior to hospitalization was 43.5 ± 38.8 hours, and mean admission NIHSS score was 10.1 ± 7.7. Total fasting Hcy in stroke patients was 10.2 ± 4.6 umol/L and did not differ significantly from controls (10.1 ± 3.6 umol/L; P = 0.88). Hyperhomocysteinemia, defined by plasma Hcy levels > 90^thpercentile of controls (>14.2 umol/L in women and >14.6 umol/L in men), was present in 7 (10.1%) stroke cases and 11 (12.8%) controls (odds ratio 0.86, 95% confidence interval 0.31 – 2.39; P > 0.05). In multiple regression analysis admission NIHSS score (but not plasma Hcy) was a significant determinant of 4 week outcome measured by GOS score (P < 0.0001).</p> <p>Conclusion</p> <p>This exploratory study found that homocysteine levels are not significantly elevated in Nigerians with acute ischaemic stroke, and admission Hcy level is not a determinant of short-term (4 week) stroke outcome.</p