Dynamic rupture initiation and propagation in a fluid-injection laboratory setup with diagnostics across multiple temporal scales.

Fluids are known to trigger a broad range of slip events, from slow, creeping transients to dynamic earthquake ruptures. Yet, the detailed mechanics underlying these processes and the conditions leading to different rupture behaviors are not well understood. Here, we use a laboratory earthquake setup, capable of injecting pressurized fluids, to compare the rupture behavior for different rates of fluid injection, slow (megapascals per hour) versus fast (megapascals per second). We find that for the fast injection rates, dynamic ruptures are triggered at lower pressure levels and over spatial scales much smaller than the quasistatic theoretical estimates of nucleation sizes, suggesting that such fast injection rates constitute dynamic loading. In contrast, the relatively slow injection rates result in gradual nucleation processes, with the fluid spreading along the interface and causing stress changes consistent with gradually accelerating slow slip. The resulting dynamic ruptures propagating over wetted interfaces exhibit dynamic stress drops almost twice as large as those over the dry interfaces. These results suggest the need to take into account the rate of the pore-pressure increase when considering nucleation processes and motivate further investigation on how friction properties depend on the presence of fluids.

Anatomy of strike-slip fault tsunami genesis.

Tsunami generation from earthquake-induced seafloor deformations has long been recognized as a major hazard to coastal areas. Strike-slip faulting has generally been considered insufficient for triggering large tsunamis, except through the generation of submarine landslides. Herein, we demonstrate that ground motions due to strike-slip earthquakes can contribute to the generation of large tsunamis (>1 m), under rather generic conditions. To this end, we developed a computational framework that integrates models for earthquake rupture dynamics with models of tsunami generation and propagation. The three-dimensional time-dependent vertical and horizontal ground motions from spontaneous dynamic rupture models are used to drive boundary motions in the tsunami model. Our results suggest that supershear ruptures propagating along strike-slip faults, traversing narrow and shallow bays, are prime candidates for tsunami generation. We show that dynamic focusing and the large horizontal displacements, characteristic of strike-slip earthquakes on long faults, are critical drivers for the tsunami hazard. These findings point to intrinsic mechanisms for sizable tsunami generation by strike-slip faulting, which do not require complex seismic sources, landslides, or complicated bathymetry. Furthermore, our model identifies three distinct phases in the tsunamic motion, an instantaneous dynamic phase, a lagging coseismic phase, and a postseismic phase, each of which may affect coastal areas differently. We conclude that near-source tsunami hazards and risk from strike-slip faulting need to be re-evaluated.

Signature of transition to supershear rupture speed in the coseismic off-fault damage zone.

Most earthquake ruptures propagate at speeds below the shear wave velocity within the crust, but in some rare cases, ruptures reach supershear speeds. The physics underlying the transition of natural subshear earthquakes to supershear ones is currently not fully understood. Most observational studies of supershear earthquakes have focused on determining which fault segments sustain fully grown supershear ruptures. Experimentally cross-validated numerical models have identified some of the key ingredients required to trigger a transition to supershear speed. However, the conditions for such a transition in nature are still unclear, including the precise location of this transition. In this work, we provide theoretical and numerical insights to identify the precise location of such a transition in nature. We use fracture mechanics arguments with multiple numerical models to identify the signature of supershear transition in coseismic off-fault damage. We then cross-validate this signature with high-resolution observations of fault zone width and early aftershock distributions. We confirm that the location of the transition from subshear to supershear speed is characterized by a decrease in the width of the coseismic off-fault damage zone. We thus help refine the precise location of such a transition for natural supershear earthquakes.

Illuminating the physics of dynamic friction through laboratory earthquakes on thrust faults.

Large, destructive earthquakes often propagate along thrust faults including megathrusts. The asymmetric interaction of thrust earthquake ruptures with the free surface leads to sudden variations in fault-normal stress, which affect fault friction. Here, we present full-field experimental measurements of displacements, particle velocities, and stresses that characterize the rupture interaction with the free surface, including the large normal stress reductions. We take advantage of these measurements to investigate the dependence of dynamic friction on transient changes in normal stress, demonstrate that the shear frictional resistance exhibits a significant lag in response to such normal stress variations, and identify a predictive frictional formulation that captures this effect. Properly accounting for this delay is important for simulations of fault slip, ground motion, and associated tsunami excitation.

The Supply of Glass at Portus Ilicitanus (Alicante, Spain): A Meta-Analysis of HIMT Glasses.

Portus Ilicitanus (Picola, Alicante) was the main sea harbour of the Roman Colonia Iulia Ilici Augusta and as such played a crucial role in the supply of fundamental commodities to the Iberian Peninsula. Excavations yielded large quantities of glass in fourth- and early fifth-century contexts. Elemental analysis of 60 samples by laser ablation - inductively coupled plasma - mass spectrometry (LA-ICP-MS) confirmed that the glasses were imported from the Eastern Mediterranean. A majority of the glasses correspond to the HIMTa primary production group, which originates from Egypt. The statistical evaluation of published data of 589 HIMT glasses further revealed differential distribution patterns of the HIMTa and HIMTb subtypes between the Eastern and Western Mediterranean, suggesting chronological trends that are linked to wider geopolitical changes. This demonstrates the need for systematic large-scale approaches to identify supply patterns and possible factors underlying geographical differences and/or chronological developments.

Diagnostic nerve blocks in the management of low back pain secondary to facet joint syndrome. / Bloqueos diagnósticos en el manejo del paciente con lumbalgia secundaria a síndrome facetario.

Low back pain is currently one of the main public health problems. Among the multiple causes, pain in the zygapophysial joints, also called facets or posterior vertebral joints, are an important cause, usually secondary to osteoarthritis. The source of low back pain is often difficult to find, making the therapeutic approach to the patient sub-optimal. Diagnostic blocks are a very important tool in establishing an adequate treatment for patients with low back pain, as long as they are performed accurately, with an adequate local anaesthetic volume, with a suitable image and fluoroscopic projection and its result are precisely interpreted. In this article a review is presented on the importance of diagnostic blocks, as well as how they should be performed in order to obtain the maximum information and the greatest therapeutic benefit.

Vegetation and terrain drivers of infiltration depth along a semiarid hillslope.

An improved understanding of the drivers controlling infiltration patterns in semiarid regions is of key importance, as they have important implications for ecosystem productivity, retention of resources and the restoration of degraded areas. The infiltration depth variability (ΔInf) in vegetation patches at the hillslope scale can be driven by different factors along the hillslope. Here we investigate the effects of vegetation and terrain attributes under hypothesis that these attributes exert a major control in ΔInf within the patches. We characterise the ΔInf within vegetation patches at a semiarid hillslope located at the Jornada Experimental Range at dry antecedent conditions preceding two winter frontal rainfall events. We measured these events that are typical during winter conditions, and are characterised by low intensity (0.67 and 4.48 mm h-1) and a total rainfall of 10.4 and 4.6 mm. High precision geo-referenced wetting front depth measurements were taken at various locations within the vegetation patches using differential GPS. Vegetation and terrain attributes were analysed to explain the ΔInf among the vegetation patches. The infiltration depths in the periphery of the patches were in general considerably deeper than those in the centre. The observations suggest that the upslope margin of the patches received additional water in the form of runon from upslope adjacent bare soil. Patch orientation with regard to the slope dictated the effect of the rest of the patch attributes and the distance to the hillslope crest on ΔInf. We found that primarily patch orientation, followed by shape and size modulate lateral surface water transport through their effects on overland flow paths and water retention; something that would be obscured under more simplistic characterisations based on bare versus uniform vegetated soil discrimination.

Who Discovered the Binary System and Arithmetic? Did Leibniz Plagiarize Caramuel?

Gottfried Wilhelm Leibniz (1646-1716) is the self-proclaimed inventor of the binary system and is considered as such by most historians of mathematics and/or mathematicians. Really though, we owe the groundwork of today's computing not to Leibniz but to the Englishman Thomas Harriot and the Spaniard Juan Caramuel de Lobkowitz (1606-1682), whom Leibniz plagiarized. This plagiarism has been identified on the basis of several facts: Caramuel's work on the binary system is earlier than Leibniz's, Leibniz was acquainted-both directly and indirectly-with Caramuel's work and Leibniz had a natural tendency to plagiarize scientific works.

Validity and reliability of the Spanish-language version of the self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) pain scale. / Validación y fiabilidad de la versión española de la escala autoadministrada de Evaluación de Signos y Síntomas Neuropáticos de Leeds (S-LANSS).

INTRODUCTION: The self-administered Leeds Assessment of Neuropathic Symptoms and Signs (S-LANSS) scale is a tool designed to identify patients with pain with neuropathic features. OBJECTIVE: To assess the validity and reliability of the Spanish-language version of the S-LANSS scale. METHODS: Our study included a total of 182 patients with chronic pain to assess the convergent and discriminant validity of the S-LANSS; the sample was increased to 321 patients to evaluate construct validity and reliability. The validated Spanish-language version of the ID-Pain questionnaire was used as the criterion variable. All participants completed the ID-Pain, the S-LANSS, and the Numerical Rating Scale for pain. Discriminant validity was evaluated by analysing sensitivity, specificity, and the area under the receiver operating characteristic curve (AUC). Construct validity was assessed with factor analysis and by comparing the odds ratio of each S-LANSS item to the total score. Convergent validity and reliability were evaluated with Pearson's r and Cronbach's alpha, respectively. RESULTS: The optimal cut-off point for S-LANSS was ≥12 points (AUC=.89; sensitivity=88.7; specificity=76.6). Factor analysis yielded one factor; furthermore, all items contributed significantly to the positive total score on the S-LANSS (P<.05). The S-LANSS showed a significant correlation with ID-Pain (r=.734, α=.71). CONCLUSION: The Spanish-language version of the S-LANSS is valid and reliable for identifying patients with chronic pain with neuropathic features.

Dielectrophoretic assembly of liquid-phase-exfoliated TiS3 nanoribbons for photodetecting applications.

Liquid-phase exfoliation is a technique capable of producing large quantities of two-dimensional materials in suspension. Despite many efforts in the optimization of the exfoliation process itself, not much has been done towards the integration of liquid-phase-exfoliated materials in working solid-state devices. In this article, we use dielectrophoresis to direct the assembly of liquid-phase-exfoliated TiS3 nanoribbons between two gold electrodes to produce photodetectors working in the visible region. Through electrical and optical measurements we characterize the responsivity of the device and we find values as large as 3.8 mA W-1, which are more than one order of magnitude higher compared to state-of-the-art devices based on liquid-phase-exfoliated two-dimensional materials assembled by drop-casting or ink-jet methods.

Experimental evidence that thrust earthquake ruptures might open faults.

Many of Earth's great earthquakes occur on thrust faults. These earthquakes predominantly occur within subduction zones, such as the 2011 moment magnitude 9.0 eathquake in Tohoku-Oki, Japan, or along large collision zones, such as the 1999 moment magnitude 7.7 earthquake in Chi-Chi, Taiwan. Notably, these two earthquakes had a maximum slip that was very close to the surface. This contributed to the destructive tsunami that occurred during the Tohoku-Oki event and to the large amount of structural damage caused by the Chi-Chi event. The mechanism that results in such large slip near the surface is poorly understood as shallow parts of thrust faults are considered to be frictionally stable. Here we use earthquake rupture experiments to reveal the existence of a torquing mechanism of thrust fault ruptures near the free surface that causes them to unclamp and slip large distances. Complementary numerical modelling of the experiments confirms that the hanging-wall wedge undergoes pronounced rotation in one direction as the earthquake rupture approaches the free surface, and this torque is released as soon as the rupture breaks the free surface, resulting in the unclamping and violent 'flapping' of the hanging-wall wedge. Our results imply that the shallow extent of the seismogenic zone of a subducting interface is not fixed and can extend up to the trench during great earthquakes through a torquing mechanism.

On the van der Pauw's method applied to the measurement of low thermal conductivity materials.

The electrical van der Pauw's method has recently been extended to measure the thermal conductivity of different elements and compounds. This technique provides an easy way to determine the sample in-plane thermal conductivity by avoiding the influence of the thermal contact resistances. However, the reported calculated error values appear to be underestimated when dealing with the materials with low thermal conductivity (<5 W/Km) at room temperature. The causes of this underestimation are investigated in this communication and it has been found that they are due to the drastic influence of conduction heat losses through the thermo-resistance wires as well as the resulting modification of the sample temperature map. Both phenomena lead to experimental values of the sample thermal conductivity, which are systematically higher than the tabulated ones. The magnitude of this systematic error is ∼100% dealing with the samples of macroscopic dimensions, and low thermal conductivity indicated that the obtained accurate measurements can be quite challenging.

Chemoselective and stereoselective lithium carbenoid mediated cyclopropanation of acyclic allylic alcohols.

The reaction of geraniol with different lithium carbenoids generated from n-BuLi and the corresponding dihaloalkane has been evaluated. The reaction occurs in a chemo and stereoselective manner, which is consistent with a directing effect from the oxygen of the allylic moiety. Furthermore, a set of polyenes containing allylic hydroxyl or ether groups were chemoselectively and stereoselectively converted into the corresponding gem-dimethylcyclopropanes in one single step in moderate to good yields mediated by a lithium carbenoid generated in situ by the reaction of n-BuLi and 2,2-dibromopropane.

Titanium carbenoid-mediated cyclopropanation of allylic alcohols: selectivity and mechanism.

A new method for the chemo- and stereoselective conversion of allylic alcohols into the corresponding cyclopropane derivatives has been developed. The cyclopropanation reaction was carried out with an unprecedented titanium carbenoid generated in situ from Nugent's reagent, manganese and methylene diiodide. The reaction involving the participation of an allylic hydroxyl group, proceeded with conservation of the alkene geometry and in a high diastereomeric excess. The scope, limitations and mechanism of this metal-catalysed reaction are discussed.

The synthesis of 3-hydroxy-2,4,8-trimethyldec-8-enolides and an approach to 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide.

The synthesis of several derivatives of 3-hydroxy-2,4,8-trimethyldec-8-enolide and attempts at the synthesis of 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (1), a structure which has been assigned to a metabolite of the phytopathogenic fungus, Botrytis cinerea, gave products whose spectroscopic data had significant differences from those reported for the natural product 1. The rare 11-membered lactone rings were constructed by ring-closing metathesis reactions. The increase in conformational restrictions imposed by the substituents has a high influence on the stereochemistry of the ring-closing metathesis reaction and gives rise to a decrease in the yield for the synthesis of 11-membered lactones. The predominant alkene which was obtained was the (Z)-isomer. The observed spectroscopic differences between the synthesized lactones and the natural product and the spectroscopic data of its acetylated derivative 26a allowed us to revise the structure 1 to that of the γ-butyrolactone 26.

Hydrogen evolution using palladium sulfide (PdS) nanocorals as photoanodes in aqueous solution.

Palladium sulfide (PdS) nanostructures are proposed to be used as photoanodes in photoelectrochemical cells (PECs) for hydrogen evolution due to their adequate transport and optical properties shown in previous works. Here, a complete morphological and electrochemical characterization of PdS films has been performed by different techniques. PdS flatband potential (Vfb=-0.65±0.05 V vs NHE) was determined by electrochemical impedance spectroscopy measurements in aqueous Na2SO3 electrolyte, providing a description of the energy levels scheme at the electrolyte-semiconductor interface. This energy levels scheme confirms PdS as a compound able to photogenerate hydrogen in a PEC. At last, photogenerated hydrogen rates are measured continuously by mass spectrometry as a function of the external bias potential under illumination, reaching values up to 4.4 µmolH2/h at 0.3 V vs Ag/AgCl.

Exploring mutasynthesis to increase structural diversity in the synthesis of highly oxygenated polyketide lactones.

The enantioselective synthesis of (2R,3R,4E,8E)-3-hydroxy-2,4,8-trimethyldeca-4,8-dienolide (5) by ring-closing metathesis is described. This compound is an analogue of 3,4-dihydroxy-2,4,6,8-tetramethyldec-8-enolide (4) which is a rare 11-membered lactone produced by the fungus, Botrytis cinerea. Mutasynthetic studies with compound 5 using two mutants of B. cinerea led to the isolation of four new highly oxygenated 11-membered lactones (11-14) in which compound 5 has been stereoselectively epoxidized and hydroxylated at sites that were not easily accessible by classical synthetic chemistry.

Repair of erosions in patients with rheumatoid arthritis treated with etanercept: magnetic resonance imaging findings after 1 year of follow-up.

OBJECTIVES: To monitor repair of bone erosions using magnetic resonance imaging (MRI) in patients with rheumatoid arthritis (RA) during etanercept combination therapy. METHOD: The study population comprised 29 RA patients [biologic-naïve, 28-joint Disease Activity Score (DAS28) ≥ 3.2] starting etanercept combination therapy with disease-modifying anti-rheumatic drugs (DMARDs) and completing the 1-year study period with the same treatment. Clinical and laboratory assessments and MRI of the hand were performed at baseline and at 1 year. MRI findings were scored by two readers using the Rheumatoid Arthritis MRI Scoring System (RAMRIS). Both readers were blind to the chronological order of the MRI scans, the identity of the patients, and clinical and other imaging data. Tenosynovitis was also scored. The intra- and inter-reader intraclass correlation coefficients (ICCs) were calculated, along with the sensitivity to change with the smallest detectable difference (SDD). Repair of erosions was defined as a RAMRIS score of at least 1 point lower than baseline. RESULTS: The mean RAMRIS score for erosions did not change but all other inflammatory MRI parameters decreased significantly. In 19 patients, the RAMRIS score for erosions remained unchanged after 1 year. In five patients the score decreased after 1 year, although the decrease exceeded the SDD in only one patient (3.4%). CONCLUSIONS: Etanercept combined with DMARDs stopped the progression of erosions, as measured by the RAMRIS, in 82.8% of our RA patients and occasional repair of bone erosions occurred after 1 year of treatment.

Does sheep selectivity along grazing paths negatively affect biological crusts and soil seed banks in arid shrublands? A case study in the Patagonian Monte, Argentina.

Domestic animals potentially affect the reproductive output of plants by direct removal of aboveground plant parts but also could alter the structure and fertility of the upper soil and the integrity of biological crusts through trampling. We asked whether sheep selectivity of plant patches along grazing paths could lead to negative changes in biological crusts and soil seed banks. We randomly selected ten floristically homogeneous vegetation stands distributed across an area (1250 ha) grazed by free ranging sheep. Vegetation stands were differently selected by sheep as estimated through sheep-collaring techniques combined with remote imagery mapping. At each stand, we extracted 15 paired cylindrical soil cores from biological crusts and from neighboring soil without crusts. We evaluated the crust cover enclosed in each core and incubated the soil samples at field capacity at alternating 10-18 °C during 24 months. We counted the emerged seedlings and identified them by species. Sheep selectivity along grazing paths was largest at mid-distances to the watering point of the paddock. Increasing sheep selectivity was associated with the reduction of the cover of biological crusts and the size and species number of the soil seed bank of preferred perennial grasses under biological crusts. The size of the soil seed bank of annual grasses was reduced with increasing sheep selectivity under both crust and no crust soil conditions. We did not detect changes in the soil seed banks of less- and non- preferred species (shrubs and forbs) related to sheep selectivity. Our findings highlight the negative effects of sheep selectivity on biological crusts and the soil seed bank of preferred plant species and the positive relationship between biological crusts and the size of the soil seed bank of perennial grasses. Accordingly, the state of conservation of biological crusts could be useful to assess the state of the soil seed banks of perennial grasses for monitoring, conservation and planning the sustainable management of grazing lands.

[Smell disorders as early diagnosis in the early stage of sinonasal polyposis]. / Alteraciones olfativas como diagnóstico precoz de la poliposis nasosinusal incipiente.

INTRODUCTION: The increasing demand for attention to olfactory disorders, along with the persistent presence of sinonasal polyposis, has opened the need to treat these pathologies in very early stages. OBJECTIVES: To demonstrate that incipient stages in sinonasal polyposis are detectable by olfactometry before radiological images, and that this detection is linked with a non-blocked area around the nasal meatus (where the olfactory cleft is located). METHODS: This study is based on data obtained from a sinonasal polyposis (degree 0 or 1) patient group (n=121) without allergies or asthma backgrounds. The patients underwent both fibroscopic and olfactometry explorations (first and fifth cranial nerve) and computed axial tomography (CT) assessment. The results were compared with the control group (n=120). RESULTS: Significant values (p<0.05) of affectation were found in decreasing olfactory levels (olfactory and trigeminal nerves) in patients with degree 0 or 1 polyposis. CONCLUSION: Olfactory disorders linked to a non-blocked area around the nasal meatus (degree 1 or 2 polyposis), together with sinonasal CT scans showing beginnings of ethmoidal inflammation, should be interpreted as incipient sinonasal polyposis.