Initial Opening Research Articles

Extensional tectonics during the Tyrrhenian back‐arc basin formation and a new morpho‐tectonic map

AbstractWe present a new tectonic map focused upon the extensional style accompanying the formation of the Tyrrhenian back‐arc basin. Our basin‐wide analysis synthetizes the interpretation of vintage multichannel and single‐channel seismic profiles, integrated with modern seismic images, P‐wave velocity models, and high‐resolution morpho‐bathymetric data. Four distinct evolutionary phases of the Tyrrhenian back‐arc basin opening are further constrained, redefining the initial opening to Langhian/Serravallian time. Listric and planar normal faults and their conjugates bound a series of horst and graben, half‐graben and triangular basins. Distribution of extensional faults, active throughout the basin since Middle Miocene, allows us to define an arrangement of faults in the northern/central Tyrrhenian mainly related to a pure shear which evolved to a simple shear opening. At depth, faults accommodate over a Ductile‐Brittle Transitional zone cut by a low‐angle detachment fault. In the southern Tyrrhenian, normal, inverse and transcurrent faults appear to be related to a large shear zone located along the continental margin of the northern Sicily. Extensional style variation throughout the back‐arc basin combined with wide‐angle seismic velocity models allows to explore the relationships between shallow deformation, faults distribution throughout the basin, and crustal‐scale processes as thinning and exhumation.

On the sensitivity of fracture mechanism to stress concentration configuration in a two-step quenching and partitioning steel

The effect of stress concentration geometry on the fracture behavior and fracture mechanisms of a two-step quenching and partitioning steel consisting of tempered martensite and retained austenite (RA) is investigated using double edge notched tension (DENT) specimens with different notch root radii. The initial notch opening is varied from a fatigue pre-crack to 15 mm radius. The fracture surface consists in flat triangular regions and slant zones. The fracture mode evolves from intergranular brittle fracture to ductile fracture with dimples. The ductile fracture process further changes from internal necking coalescence to a void sheet shear type coalescence when increasing the notch root radius. A similar transition of the fracture behavior is observed along the ligament of the DENT specimen. This change in the fracture mode results from a decrease of the stress triaxiality. The essential work of fracture is equal to $$40\hbox { kJ/m}^{{2}}$$. This is small when looking at the large value of the product of ultimate tensile strength and total elongation ($$\sim 25, 000\, \hbox {MPa}{\cdot }$$%). The small fracture toughness is ascribed to an intergranular fracture mode, which results from the distribution of blocky RA islands along the boundaries of martensitic packets and from the large stress concentration near the notch tip. A proper control of both the amount and morphology of RA during microstructure design is thus essential to generate the best compromise between tensile properties and fracture toughness, and to avoid the relatively low toughness and more brittle failure observed when stress triaxiality increases.

2‐Aryl‐3‐Vinyl Substituted Imidazo[1,2‐a]pyridines and Fluorescent Electrocyclization Derivatives therefrom

AbstractA collection of 2‐aryl‐3‐vinylimidazo[1,2‐a]pyridines, substituted on the pyridine ring and/or the aryl substituent, can be obtained by reaction of 2‐aminopyridines with properly substituted nitrobutadienes, originated by an initial ring opening of a nitrothiophenic precursor. Although the aza‐Michael addition of 2‐aminopyridine on a nitrovinyl moiety is the starting point of classic approaches to imidazopyridines, the final structures generated herein are the result of a cascade process made possible by the particular functionalization on the conjugated systems. Beside the general interest inherent to the pharmacologically versatile imidazo[1,2‐a]pyridine structural motif, the substituents present in the obtained compounds allow specific synthetic elaboration to e. g. polycyclic fluorescent heterocycles.

Stereocontrolled Microwave-Assisted Domino [3,3]-Sigmatropic Reactions: A Winstein-Overman Rearrangement for the Formation of Differentiated Contiguous C-N Bonds.

A domino [3,3]-sigmatropic rearrangement sequence employing a sequential reversible allylic azide rearrangement followed by an irreversible Overman reaction provides a new route to the formation of two contiguous C-N bonds. The reaction occurs in a stereocontrolled fashion in two steps from readily available alkenyl epoxides via initial azide anion ring opening of the epoxides.

Implementation of Character-Based Central Learning Program in Kindergarten al-Irsyad al-Islamiyyah Purwokerto

This research is naturalistic qualitative research aimed at describing the implementation of character-based learning center programs in kindergarten al-Irsyad al-Islamiyyah Purwokerto. The results showed that the implementation of learning centers carried out three main activities, namely the initial activities, opening activities, and core activities. In the core activities, three activities are carried out, namely the footing before playing, the footing when playing and the footing after playing. Internalization of character values in early childhood can be done both in the initial activities, opening activities, and core activities. Internalization of character values through center learning can be done optimally in the core activities. In stepping activities before playing children are introduced to the rules of the game that can make children have discipline. In the foothold when playing children play creatively and collaboratively according to the rules of the game. While in foothold activities after playing children are taught to be independent, namely by solving their problems and tidying up the toy equipment they use. The center learning program will be more effectively carried out to shape the character of students if it is accompanied by the implementation of habituation activities in the initial activities, opening activities, and final activities.DOI: http://doi.org/10.31098/ijeiece.v1i2.26

Implementation of Character-Based Central Learning Program in Kindergarten al-Irsyad al-Islamiyyah Purwokerto

This research is naturalistic qualitative research aimed at describing the implementation of character-based learning center programs in kindergarten al-Irsyad al-Islamiyyah Purwokerto. The results showed that the implementation of learning centers carried out three main activities, namely the initial activities, opening activities, and core activities. In the core activities, three activities are carried out, namely the footing before playing, the footing when playing and the footing after playing. Internalization of character values in early childhood can be done both in the initial activities, opening activities, and core activities. Internalization of character values through center learning can be done optimally in the core activities. In stepping activities before playing children are introduced to the rules of the game that can make children have discipline. In the foothold when playing children play creatively and collaboratively according to the rules of the game. While in foothold activities after playing children are taught to be independent, namely by solving their problems and tidying up the toy equipment they use. The center learning program will be more effectively carried out to shape the character of students if it is accompanied by the implementation of habituation activities in the initial activities, opening activities, and final activities.

Experimental investigation on mechanical behavior of segmental joint under combined loading of compression-bending-shear

The non-circular tunnels, for example the quasi-rectangular tunnel, may generate a considerable shear force at their shoulder joints owing to the geometry effect. To investigate the shear force effect on the mechanical behavior (e.g., capacity, deformation and duality) of the segment joint, a series of full-scale mechanical loading tests were conducted and reported in this paper. The loading scenarios include the combined axis force and moment scenario (N-M), and the combined axis force, moment and shear force (N-M-Q) scenario. Both the positive bending moment and negative bending moment are considered. DIC technique is also adopted to capture the detailed cracking process in the N-M-Q loading test. The test results reveal that the mechanical response of the segmental joint under both N-M and N-M-Q loading scenarios can be divided into three stages, which are separated by the initial joint opening and the initiation of cracks. The shear force would lead to a larger deformation (e.g., deflection, joint opening and rotational angle) before the failure but result in a brittle failure of the segment joint. Moreover, the shear force could reduce the moment bearing capacity under the positive moment loading condition while has little effect under the negative moment loading condition. These shear force effects are thought to be caused by the shear induced dislocation and inclined cracks.

Role of Stomatal Conductance in Modifying the Dose Response of Stress-Volatile Emissions in Methyl Jasmonate Treated Leaves of Cucumber (Cucumis sativa).

Treatment by volatile plant hormone methyl jasmonate (MeJA) leads to release of methanol and volatiles of lipoxygenase pathway (LOX volatiles) in a dose-dependent manner, but how the dose dependence is affected by stomatal openness is poorly known. We studied the rapid (0–60 min after treatment) response of stomatal conductance (Gs), net assimilation rate (A), and LOX and methanol emissions to varying MeJA concentrations (0.2–50 mM) in cucumber (Cucumis sativus) leaves with partly open stomata and in leaves with reduced Gs due to drought and darkness. Exposure to MeJA led to initial opening of stomata due to an osmotic shock, followed by MeJA concentration-dependent reduction in Gs, whereas A initially decreased, followed by recovery for lower MeJA concentrations and time-dependent decline for higher MeJA concentrations. Methanol and LOX emissions were elicited in a MeJA concentration-dependent manner, whereas the peak methanol emissions (15–20 min after MeJA application) preceded LOX emissions (20–60 min after application). Furthermore, peak methanol emissions occurred earlier in treatments with higher MeJA concentration, while the opposite was observed for LOX emissions. This difference reflected the circumstance where the rise of methanol release partly coincided with MeJA-dependent stomatal opening, while stronger stomatal closure at higher MeJA concentrations progressively delayed peak LOX emissions. We further observed that drought-dependent reduction in Gs ameliorated MeJA effects on foliage physiological characteristics, underscoring that MeJA primarily penetrates through the stomata. However, despite reduced Gs, dark pretreatment amplified stress-volatile release upon MeJA treatment, suggesting that increased leaf oxidative status due to sudden illumination can potentiate the MeJA response. Taken together, these results collectively demonstrate that the MeJA dose response of volatile emission is controlled by stomata that alter MeJA uptake and volatile release kinetics and by leaf oxidative status in a complex manner.

Late Triassic back-arc spreading and initial opening of the Neo-Tethyan Ocean in the northern margin of Gondwana: Evidences from Late Triassic BABB-type basalts in the Tethyan Himalaya, Southern Tibet

The tectonic evolution of the Neo-Tethyan oceanic plate between the Indian Plate and the Lhasa Terrane is a key issue for the evolution of Gondwana and formation of the Tibetan Plateau. In this paper we report on the geochemistry, SrNd isotope compositions, and zircon UPb dating of Late Triassic basalts from the Nieru Formation (T3n) in the Kampa region, southern Tibet. The basalts have relatively low contents of MgO, TiO2, and total alkalis (K2O + Na2O), and they have affinities to tholeiitic basalt. They exhibit weakly fractionated rare earth element (REE) patterns with slight depletions in LREEs and slightly negative Eu anomalies on a chondrite-normalized diagram. On a primitive-mantle-normalized spider diagram, they are characterized by slight enrichments in large ion lithophile elements (LILEs) and relatively flat patterns of high field strength elements (HFSEs), except for depletions in Ba, Nb, Ta, and Ti. Their initial 87Sr/86Sr ratios vary from 0.718133 to 0.738977 and εNd(t) values are relatively depleted (4.09–5.22), similar to mid-ocean ridge basalts in the Yarlung Zangbo ophiolite. We propose the T3n basalts were derived from a shallow and depleted mantle source by relatively high-degree partial melting in the spinel stability field. They underwent slight crustal contamination as well as the fractional crystallization of clinopyroxene. The T3n basalts are similar to typical back-arc basin basalts (BABB) such as the Okinawa BABB. This indicates an extensional back-arc-basin setting along the northern margin of Gondwana during the Late Triassic. The initial opening of the Neo-Tethyan Ocean was related to the southwards subduction of the Paleo-Tethyan oceanic plate and back-arc-basin spreading during the Late Triassic. Magmatic activity along the passive continental margin records key information on continental break-up and incipient ocean development.

Combined posterior cruciate ligament and chronic posterolateral corner deficiency in varus knee, two-stage reconstruction

Background Conservative management of chronic posterolateral corner (PLC) knee injuries had a bad repetition and often followed by poor outcomes. In patients who had associated posterior cruciate ligament [PCL] and chronic PLC knee injuries with varus knee deformity, failure to correct the mechanical axis by correcting varus was usually followed by failure of the posterolateral knee repair or reconstruction. Aim of the study To assess prospectively the results of treatment of associated PCL and chronic PLC injury in the varus knee, with a two-stage procedure. Initial high tibial medial opening wedge osteotomy was followed by PCL reconstruction. Methods This study included 10 patients who had associated PCL and chronic PLC deficiency in varus knee who were treated by two-stage surgical technique, first stage was high tibial medial opening wedge osteotomy to align the mechanical axis and correct varus deformity, then PCL ligament reconstruction in the second stage. Results According to the International Knee Documentation Committee, the 10 patients included in the study [100%] were graded as grade C (abnormal) or D (sever abnormal) preoperatively, while 8 of the 10 patients [80%] were graded as grade A (normal) or B (nearly normal), and 2 patients [20%] were rated as abnormal grade C at final follow-up scoring. Statistically significant improvement was achieved. Radiologically, the average mechanical axis that preoperatively passed within the medial tibial plateau with varus deformity ranged between 10 and 15° in our cases, while the mechanical axis postoperatively passed through the mid of tibial plateau or slightly within the lateral tibial plateau with full correction of the deformity with valgus angle ranged from 5 to 10°. The preoperative posterior tibial sagittal slope angle was average 7.8°, which became 10.5° in the last follow-up visit. Conclusion Two-stage reconstruction of the knee in cases who had PLC injuries associated with varus knee, starting by proximal tibial medial opening wedge osteotomy followed by reconstruction of PCL, is a valuable technique and had good results.

Geochemistry and U-Pb ages of the diabases from the Luoji area, western Yunnan, China: implications for the timing of initial rifting of the Ganzi-Litang Ocean

Detailed geochemical and U-Pb studies of two diabases (Luoji and Cuiyi) from the Luoji area have been undertaken. The diabases are high-K calc-alkaline and belonging to the tholeiitic series, enriched in large ion lithophile elements, Ti, Zr and light rare earth elements, and depleted in high field strength elements. These characteristics are different from the oceanic island basalt but highly consistent with the continental rift basalt, indicating the Luoji and Cuiyi diabases are the products of the intracontinental rift related to the initial opening of the Ganzi-Litang Ocean. The Luoji and Cuiyi diabases originated from an enriched mantle source with a small degree of crustal contamination during their emplacement. Zircon U-Pb ages show that the Luoji and Cuiyi diabases were emplaced at 293.4 +/- 5.4Ma. Therefore, we propose that the time of initial rifting of the Ganzi-Litang Ocean occurred during the very Early Permian.

Silurian anorogenic basic and acidic magmatism in Northwest Turkey: Implications for the opening of the Paleo-Tethys

The Sakarya Zone (northern Turkey) is a Gondwana-derived continental block accreted to northern Laurussia during the Carboniferous, and is regarded as the eastward extension of Armorica. Timing of its detachment from the northern margin of Gondwana, thus opening of the Paleo-Tethys, is poorly known. Here, we report on metagranite and amphibolite with Silurian igneous crystallization ages from the Early Carboniferous high-temperature/middle to low-pressure amphibolite-facies metamorphic rocks of the Sarıcakaya Massif within the Sakarya Zone (NW Turkey). The metagranite-amphibolite complex is exposed mainly along the southern margin of the Sarıcakaya Massif over an area of ca. 12 km by 1.5 km. The metagranite contains preserved domains of porphyric texture, indicative of derivation from a former granite porphyry. The amphibolite is devoid of any relict igneous texture. Both the metagranite and amphibolite are crosscut by late up to 50 cm thick felsic veins. Uranium-Pb dating on igneous zircons from both metagranite and amphibolite yielded Silurian ages of ca. 419 ± 6 to 434 ± 7 Ma (2σ), and on those from a felsic vein an age of 319 ± 5 Ma (2σ) (Late Carboniferous). Geochemically, amphibolite displays anorogenic transitional tholeiitic to alkaline signatures. Initial εHf values of the igneous zircons from both metagranite and amphibolite show a large variation with medial values of −16 to −9 and + 3 to +6, respectively. Thus, the protoliths of amphibolite were derived from melts of depleted mantle, and those of the metagranite, on the other hand, from melts of reworked crustal material. We suggest that the Silurian anorogenic magmatism is related to a rifting event at the northern margin of Gondwana leading to the detachment of the Sakarya Zone and hence placing an age on the initial opening of the Paleo-Tethys. This interpretation is based on (i) the presence of Late Silurian to Devonian deep-sea sedimentary blocks in the Paleo-Tethyan accretionary complexes, and (ii) the resemblance of the UPb age spectra of detrital zircons in the metaclastic sequence of the Sarıcakaya Massif to those of Cambro-Ordovician sandstones in Jordan (Gondwana), and (iii) the local occurrence of anorogenic A-type granites of Late Ordovician-Silurian age in the Anatolide-Tauride Block, a continental block which rifted from Gondwana during the Early Triassic. Wholly anorogenic nature of the Late Ordovician to Silurian igneous rocks in the Sarıcakaya Massif and reported in literature does not support the opening of the Paleo-Tethys as back-arc ocean, as suggested in most paleogeographic reconstructions.

A Comparison of User Behaviors for a Fertility-Tracking App: Does Training in an NFP Method Improve Persistence and Use?

"CycleProGo™ users with NFP training were more persistent and diligent about daily data input than those without training."

From “bringing-in” to “going-out”: transnationalizing China’s Internet capital through state policies

The exponential growth in China’s information and communication technology (ICT) sector has attracted increasing academic interest. Mainstream accounts have focused on issues of access and control, and critical scholars have examined the dynamic shaping forces. Building on the framework of political economy, this study adopts a historical approach to the Internet as a complex site of power interactions. The study examines the historical process by which China has opened its ICT industry to transnational capital. In tracing the policy changes related to this move, this study examines the historical stages that have been critical in the transnationalization of China’s Internet: the initial opening of China’s ICT sector; the introduction of financial capital; and the recent “going-out” initiatives. In doing so, the study addresses a gap in the current scholarship regarding the history of bridging China’s Internet to transnational capital, particularly the regulatory context. The findings of this study contribute to the understanding of the dialectical role of the Chinese state, which has been more constituting than containing in transnationalizing China’s Internet.

Financial Inclusion of the Poor in Developing Economies in the Twenty-first Century: Qualitative Evidence from Rural Uganda

ABSTRACT The main purpose of this study is to examine financial inclusion of the poor by formal financial services’ providers in developing economies with data obtained from rural Uganda. Exploratory research design was used in this study and 50 poor households’ heads were interviewed to get their responses on being financially included by microfinance deposit-taking institutions (MDIs) in Uganda. The qualitative data collected from the interviews were analyzed using NVivo software and verbatim text were used to explain emergent themes and sub-themes from this study. The findings revealed that suitable initial account opening fees, minimum deposit requirement, limited eligibility requirements, permanence of use, depth of financial services and products, relevance of financial services/products in terms of convenience, flexibility, reliability, continuity, safety, dignity of treatment (clients’ protection), and welfare improvement are important determinants of financial inclusion of the poor in developing economies, especially in rural Uganda.

Jet-driven bubbles in Fanaroff–Riley type-I sources

Abstract Observations of several Fanaroff–Riley (FR) type-I sources reveal outflowing bipolar bubbles of hot gas surrounded by a weak forward shock. We consider the possibility that these bubbles were driven by choked relativistic jets that failed to penetrate the ambient intracluster medium. Using new results on choked jets linking the geometry of the forward shock to the jet properties, we infer robust limits on the radius Rch at which the jet was quenched in five well-studied FR type-I sources, finding typically Rch ∼ 10 kpc. We further show that, in order to reach this radius in less than the current age of the system, the jet must have been tightly collimated, with the jet head subtending an angle of $\theta _{\rm h}\lesssim 2^{\circ }$. The ambient pressure is not high enough to explain this collimation, suggesting that the jet was collimated by interaction with its own cocoon. Although the choking radius is well-constrained, we find a degeneracy between the initial jet opening angle before collimation, θ0, and the duration of jet activity, tb, with $(t_{\rm b}/1\rm Myr)(\theta _0/5^{\circ })^{-2}\sim 0.1$. We speculate that the working time and/or opening angle of the jet may be important factors contributing to the FR type-I/type- II morphology in galaxy clusters, with short-lived or wide jets being choked to form bipolar bubbles filled with diffuse radio emission, and longer-lived or narrow jets successfully escaping the cluster core to produce cocoons with radio hotspots.

Carotid Artery Injury during Transsphenoidal Pituitary Surgery: Lessons from a 15-Year Modern Microsurgery Cohort.

Background Internal carotid artery (ICA) injury is a rare but potentially catastrophic complication of transsphenoidal resection (TSR) of pituitary tumors, potentially resulting in a host of deficits due to the risk of hemorrhage, ischemia, or even death. The endoscopic endonasal approach (EEA) has gained considerable popularity in the modern era, with few busy neurosurgeons remaining committed to practicing transnasal pituitary microsurgery. Our objective was therefore to characterize the overall incidence of ICA injury in a large, longitudinal, single-surgeon microscopic TSR series conducted during the modern EEA era. Methods Retrospective case series. Results Overall TSR volume by the senior author (F.B.M.) was 817 pituitary tumors during the study period, 2002 to 2017. Within that cohort, two instances of ICA injury were identified (0.2%), including one each with Cushing's disease and acromegaly, both of whom ultimately recovered without residual neurologic deficit. No pediatric injuries were identified. Conclusion Vascular injury is an exceedingly rare complication of transsphenoidal pituitary surgery. Adjuncts to prevent this complication include careful review of the coronal magnetic resonance imaging, identification of the midline, as needed use of the Doppler, and initial caudal opening of the sellar dura. Although potentially disastrous, good neurologic outcomes may be obtained, with immediate judicious packing followed by immediate digital subtraction angiography to assess vessel patency and secondary complications such as pseudoaneurysm.

A plane strain analysis of the elastostatic fields near the notch-tip of a Blatz-Ko material

An asymptotic plane strain analysis is carried out in order to study the notch problem in a homogeneous isotropic compressible hyperelastic material whose behavior is governed by the Blatz-Ko constitutive law. The work is realized within the framework of the fully nonlinear fracture mechanics at large strain. Close to the notch tip, a stress-free state is assumed in the notch edges, while at infinity (sufficiently far to the notch tip) fracture modes I and II are considered. The results emphasizes many discrepancies with linear theory predictions like the emergence of a logarithmic singularity and show that solution depends on the notch initial opening angle.

Experimental Investigation on Chemical Grouting in a Permeated Fracture Replica with Different Roughness

This paper presents an experimental investigation on chemical grouting in a permeated fracture replica considering its roughness. Tests of grouting with flowing water in the fracture replica were carried out under different Bardon’s standard roughness profiles. The interactions between influential factors were considered and an experimental platform for grouting in rough fractures with flowing water was established. The effect of chemical grouting in fractures with flowing water was investigated using orthogonal experiment. The joint roughness coefficient (JRC), the initial water flow rate, the gel time, and the fracture opening were selected as factors in the orthogonal experiment. The results show that there is a positive correlation between the water plugging rate and JRC, and negative correlations between the water plugging rate and the initial water flow rate, gel time, and fracture opening. The change curve of the water flow rate is divided into three categories: Single platform decreasing type, double platform decreasing type, and multi-peak fluctuating type. The curve of seepage pressure contains three categories: Single peak type, multi-peak type and platform type. The results provide a reference for grouting in rock fractures.

Effects of loading rate on crack growth behavior in carbon fiber reinforced polymer composites using digital image correlation technique

The aim of this work is to investigate the effect of the loading rate on the crack growth behavior in carbon fiber reinforced polymer composites, under mode I monotonic tensile loading. For such objective, inter-laminar fracture toughness tests were performed on double cantilever beam (DCB) specimens, according to the ASTM-D5528 standard. The initial crack tip opening displacement (CTOD) was obtained by employing the digital image correlation (DIC) technique. Then, the strain energy release rate and the R-curve were obtained from the force-displacement curve, based on the modified beam theory (MBT), the compliance calibration method (CC) and the modified compliance calibration method (MCC). No significant variation was observed between results of these methods. Obtained results also indicated no considerable changes in the maximum force, by increasing the loading rate. The relation between the initial CTOD and the crack length was nonlinear, due to fiber bridging during testing. In addition, increasing the loading rate caused extended steady state fiber bridging zones.