Shortening Estimates Research Articles

Motion correction of wide-detector 4DCT images for cardiac resynchronization therapy planning

BackgroundLead placement at the latest mechanically activated left ventricle (LV) segments is strongly correlated with response to cardiac resynchronization therapy (CRT). We demonstrate the feasibility of a cardiac 4DCT motion correction algorithm (ResyncCT) in estimating LV mechanical activation for guiding lead placement in CRT. MethodsSubjects with full cardiac cycle 4DCT images acquired using a wide-detector CT scanner for CRT planning/upgrade were included. 4DCT images exhibited motion artifact-induced false-dyssynchrony, hindering LV mechanical activation time estimation. Motion-corrupted images were processed with ResyncCT to yield motion-corrected images. Time to onset of shortening (TOS) was estimated in each of 72 endocardial segments. A false-dyssynchrony index (FDI) was used to quantify the extent of motion artifacts in the uncorrected and the ResyncCT images. After motion correction, the change in classification of LV free-wall segments as optimal target sites for lead placement was investigated. ResultsTwenty subjects (70.7 ​± ​13.9 years, 6 female) were analyzed. Motion artifacts in the ResyncCT-processed images were significantly reduced (FDI: 28.9 ​± ​9.3 ​% vs 47.0 ​± ​6.0 ​%, p ​< ​0.001). In 10 (50 ​%) subjects, ResyncCT motion correction yielded statistically different TOS estimates (p ​< ​0.05). Additionally, 43 ​% of LV free-wall segments were reclassified as optimal target sites for lead placement after motion correction. ConclusionsResyncCT significantly reduced motion artifacts in wide-detector cardiac 4DCT images, yielded statistically different time to onset of shortening estimates, and changed the location of optimal target sites for lead placement. These results highlight the potential utility of ResyncCT motion correction in CRT planning when using wide-detector 4DCT imaging.

Assessing drivers of high exhumation magnitudes and young cooling ages in the eastern central Andes, southern Peru (13–18°S)

The potential structural controls on exhumation across the southern Peruvian Andes are not well understood, in part due to limited structural studies that co-locate with thermochronometric datasets. We integrate these two datasets and evaluate the relative contribution that fault geometry, magnitude, and shortening rate have on predicted cooling ages. Here we present a balanced cross-section constructed using new structural observations. This section, combined with existing thermochronometer data and a thermokinematic model, investigates the drivers of high exhumation and young canyon thermochronometric ages along the deeply incised Marcapata canyon in southern Peru. Together, these approaches constrain the timing and magnitude of exhumation in this portion of the southern Peruvian Andes and provide a mechanism for documenting how the internal architecture changes along strike.The balanced cross-section (oriented N30E) covers the Subandean Zone to the northeast, the Marcapata canyon on the eastern flank of the southern Peruvian Andes, and the Altiplano-Eastern Cordillera boundary to the southwest (13–18° S). Exhumation is constrained by four low-temperature thermochronometer systems, including apatite and zircon (U-Th)/He (AHe and ZHe, respectively) and fission-track (AFT and ZFT, respectively). The youngest AHe (∼1–3 Ma), AFT (∼3–7 Ma), ZHe (∼4–7 Ma), and ZFT (∼14–17 Ma) ages are located in the center and valley bottom of the Marcapata canyon. The thermokinematically modeled cross-section produces cooling ages determined by fault geometry and kinematics. Reset ZFT ages require burial of Ordovician rocks in excess of 5.5 km above the original 6.5 km depositional depth. We find that the ZFT and ZHe ages in the Eastern Cordillera are sensitive to the history and magnitude of burial, age and location of uplift, and canyon incision. Canyon incision is required to reproduce the youngest canyon thermochronometric ages while slow shortening rates from ∼10 Ma to Present are required to reproduce interfluve thermochronometric ages. Shortening is accommodated by basement faults that feed slip up through three different décollement levels before reaching the surface. The proposed stacked basement geometry sets the first-order cooling signal seen in modeled ages. We determined that the total shortening in this section from the Subandean Zone to the Altiplano is 147.5 km, similar to shortening estimates in an adjacent thermo-kinematically modeled section in the San Gabán canyon 50 km to the southeast. Both the ZHe and ZFT ages in the Marcapata section (4–5 and 14 Ma) are noticeably younger than cooling ages from the San Gabán section (16 and 29 Ma). The Marcapata section's higher magnitude of exhumation is due to a repetition of basement thrusts that continues to elevate the Eastern Cordillera while active deformation occurs in the Subandean Zone. The youngest thermochronometric ages in all four systems are co-located with the overlapping basement thrust geometry. This basement geometry, kinematic sequence of deformation, and canyon incision co-conspire to produce the young cooling ages observed in the Eastern Cordillera.

Kinematic analysis of the mesozoic - Early Cenozoic deformation in the paipote basin (27°10′S)

An integrated structural and kinematic study focused on the characterization of an Andean Mesozoic basin was carried out in the upper stream of the Paipote Creek, in the western limit of the Southern Puna, Fault slip data analysis (n = 80) and structural observations at different scales were collected from Triassic to Upper Cretaceous volcanic and sedimentary units to constrain the structural architecture and the kinematic evolution of the area. Regional observations provide evidence for syntectonic extensional deposition during the Triassic - Jurassic and positive tectonic inversion from at least the Late Jurassic. Extensional features such as growth strata, harpoon structures and roll-over anticlines, helped to infer two main depocenters controlled by west dipping listric faults. E-W extension directions have been recognized in Triassic - Jurassic units, linked to an extensional basin architecture, and mixed contraction directions were related to compressional and strike-slip deformation in the area. A forward model is proposed based on the interpreted architecture in depth of the basin, defining two major depocenters that, together, define the Paipote basin. A shortening estimate of 21% (5,44 km) was calculated for the basin, wich corresponds to the lowest shortening values reported for the Triassic-Jurassic basins in the Atacama region. The strike-slip deformation can be associated previously with recognized NW-SE strike-slip faults, and aids in proposing the Paipote basin as a transitional zone between the Lautaro basin to the south and the Potrerillos basin to the north.

Intracontinental convergence accommodated by underthrusting of Tarim Basin beneath central Tian Shan, Central Asia: Insights from Cenozoic upper crust deformation across the western Kepingtage fold-and-thrust belt in the northern Tarim Basin

The way in which intracontinental convergence caused by remote continent-continent collision has been accommodated remains debatable, but it is attributed to either pure shear thickening or continental subduction/underthrusting. Quantification of the deformation architecture of the upper crust and its shortening is vital for testing these competing models. For this purpose, we conducted quantitative analyses of four seismic reflection profiles along the western Kepingtage fold-and-thrust belt of the intracontinental convergence zone between the northern Tarim Basin and the central Tian Shan, a result of the remote India-Eurasia collision, which capture the structures of the upper crust and constrain the amount of shortening in the region. The structural analyses show a thin-skinned style of deformation of the western Kepingtage fold-and-thrust belt, with minimum north−south shortening estimates of ∼71.1 km (∼46.6% strain), ∼76.3 km (∼51.4% strain), ∼67.1 km (∼56.1% strain), and ∼53.0 km (∼49.9% strain), respectively, from east to west. Assuming that coupling shortening occurred across the entire crust and an initial crustal thickness of ∼41−46 km, these shortening ratios would produce a ∼83−95-km-thick crust along the northern Tarim Basin, which is significantly larger than the actual thickness previously reported. This inconsistency leads us to rule out the pure-shear thickening model, which predicts crustal-scale coupling deformation. Alternatively, our results imply that the crust of the northern Tarim Basin was deformed in a decoupling style. These results, combined with those of previous studies, lend support to the intracontinental underthrusting model. We suggest that both the upper crustal fold-and-thrust belts and the lower crustal underthrusting of the northern Tarim Basin accommodated intracontinental convergence.

Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

Introduction: The East Iran orogen has experienced multiple buckling phases resulting in the formation of strike-slip fault splays. The geometric and kinematic characteristics of these splays are influenced by folding mechanisms. This study focuses on investigating the structural characteristics and tectonic evolution model of the Khousf splay, located in the northern terminus of the Nehbandan right-lateral strike-slip fault system.Methods: Field visits and geometrical properties from map views were used to analyze the structural features of the Khousf splay. The splay was found to consist of a multi-plunging anticline and syncline, referred to as the Khousf anticline and Khousf syncline, respectively. Flexural slip was identified as a significant mechanism for the formation of these structures. Structural evidence, including parasitic folds, active folds, and strike-slip duplexes, suggested that flexural slip occurred on discrete movement horizons among the rock units.Results: Analysis of the parasitic folds in the cores and limbs of the Khousf anticline and syncline revealed M, W, Z, and S shapes, with complex slicken-line patterns observed on faults parallel to the beds at the limbs. The analysis results indicated strain partitioning and inclined left- and right-lateral transpressional zones. Shortening estimates obtained from profiles in the Shekarab inclined transpressional zone were approximately 33%, 65%, and 68% for NE-SW, N-S, and NW-SE profiles, respectively. In the Arc area, which is the core of the anticline, shortening estimates from NE-SW and N-S profiles ranged from 14% to 10%. Structural analysis of the folds in this area revealed broad, close, semi-elliptical, and parabolic shapes, suggesting that secondary folds with NW-SE axis directions have been superimposed on the first-generation folds with E-W axis directions in the Khousf refolded splay.Discussion: The findings of this study highlight the structural characteristics and tectonic evolution model of the Khousf splay in the northern terminus of the Nehbandan right-lateral strike-slip fault system. The results suggest that flexural slip played a crucial role in the formation of the multi-plunging anticline and syncline in the Khousf splay. The presence of parasitic folds and complex slicken-line patterns on faults indicate the complexity of deformation processes. The observed strain partitioning and inclined transpressional zones suggest a complex tectonic history in the study area. The superimposition of secondary folds with different axis directions on first-generation folds adds further complexity to the structural evolution of the Khousf refolded splay. Overall, this study provides new insights into the structural characteristics and tectonic evolution of the Khousf splay in the East Iran orogen.

Where is the zero of Tardieu for proximal trans-joint lower limb muscles? The relevance for the estimation of muscle shortening and weakness.

Where is the zero of Tardieu for proximal trans-joint lower limb muscles? The relevance for the estimation of muscle shortening and weakness.

The usefulness of QRS Index for prediction of echocardiographic response in cardiac resynchronization therapy: a multicenter study.

The association between QRS narrowing and response to cardiac resynchronization therapy (CRT) has been investigated by several studies, but their findings remain inconclusive. Aim of our study was to explore the relationship between QRS Index and echocardiographic response to CRT. This multicenter, retrospective analysis included 326 consecutive patients (mean age was 70.0±10.1 years old; males 76.7%) who underwent CRT-D implantation in primary and secondary prevention between 2018 and 2020. The estimation of QRS shortening after CRT-D implantation was precisely assessed through the QRS Index, calculated as follows: [(QRS duration before implantation - paced QRS duration)/QRS duration before implantation]*100. After a mean follow-up of 12.7±4.5 months, 55.2% (180/326) of the patients showed an echocardiographic response to CRT. The median [25-75th] QRS Index was 3.85% [-14.1% - +13.9%]. The best predictive cut-off value of QRS Index was 1.40% (sensitivity 70.4%, specificity 64.5%, AUC 0.70). In patients with left bundle branch block, the median [25-75th] QRS Index was 9.85% [+3.87% - +16.7%]. In this subgroup, the AUC was 0.737 and the best predictive cut-off of QRS Index was 2.20% (sensitivity 78.3%, specificity 67%). The multivariable model showed that only left ventricular ejection fraction and QRS Index were independently associated with CRT response (respectively OR 0.92, CI 95% 0.86-0.98, P=0.01 and OR 1.057, CI 95% 1.026-1.089, P<0.001). the QRS Index tightly correlated with CRT response. Only LVEF and QRS Index were independently associated with echocardiographic response to CRT.

Total Shortening Estimates Across the Western Greater Caucasus Mountains from Balanced Cross Sections and Area Balancing

The Greater Caucasus orogen forms the northern edge of the Arabia-Eurasia collision zone. Although the orogen has long been assumed to exhibit dominantly thick-skinned style deformation via reactivation of high-angle extensional faults, recent work suggests the range may have accommodated several hundred kilometers or more of shortening since its ~30 Ma initiation, and this shortening may be accommodated via thin-skinned, imbricate fan-style deformation associated with underthrusting and/or subduction. However, robust shortening estimates based upon surface geologic observations are lacking. Here we present line-length and area balanced cross sections along two transects across the western Greater Caucasus that provide minimum shortening estimates of 130-200 km. These cross sections demonstrate that a thin-skinned structural style provides a viable explanation for the structure of the Greater Caucasus, and highlight major structures that may accommodate additional, but unconstrained, shortening.

Deformation structural style of the rioni foreland fold-and-thrust belt, western greater caucasus: Insight from the balanced cross-section

The Rioni foreland fold-and-thrust belt is part of the Greater Caucasus pro-wedge and is one of the most important examples of the collision-driven far-field deformation of the Arabia-Eurasia convergence zone. Here we show the deformation structural style of the Rioni foreland fold-and-thrust belt based on seismic reflection profiles and regional balanced cross-section. The main style of deformation within the Rioni foreland fold-and-thrust belt is represented by a set of fault-propagation folds, duplexes, and triangle zone. The regional balanced cross-section shows that fault-propagation folds above the upper detachment level can develop by piggyback and break-back thrust sequences. Formation of fault-bend fold duplex structures above the lower detachment is related to piggyback thrust sequences. A balanced section restoration of compressional structures across the Rioni foreland fold-and-thrust belt provides a minimum estimate of shortening of −40%, equivalent −42.78 km. The synclines within the Rioni foreland fold-and-thrust belt are filled by the Middle Miocene-Pleistocene shallow marine and continental syn-tectonic sediments, forming a series of typical thrust-top basins. Fault-propagation folds and duplex structures formed the main structure of the thrust-top basin. The evolution of the thrust-top basins was mainly controlled by the kinematics of thrust sequences. Using end-member modes of thrust sequences, the thrust-top basins are divided into: 1) Type I-piggyback basin, 2) Type II-break-back basin, and 3) Type III—formation of thrust-top basin characterized by bi-vergent geometry and related to combined, piggyback and piggyback back thrust sequences.

Paleomagnetism and geochronology of upper Eocene volcanic rocks from the western Qiangtang block: Constraints on the post-collisional shortening in western Tibet

Understanding the dynamics of the uplift of the Tibetan blocks requires constraints on the timing and magnitude of the crustal shortening accommodated by the different blocks. However, the estimates of the magnitude of post-collisional intra-Asian convergence range from >3000 km to a few hundred kilometers. Here we present new paleomagnetic and geochronological results from the Meisu Formation lavas on the southwestern margin of the western Qiangtang block, western Tibet. Zircon U/Pb data reveal that these volcanic rocks erupted during the late Eocene (∼40 Ma). Following progressive thermal demagnetization, stable characteristic remanent magnetizations (ChRMs) were successively isolated from 28 sites. These ChRMs passed the fold and reversal tests, consistent with a primary remanence. The paleopole at 50.2°N, 163.2°E with A 95 = 5.9° yields a paleolatitude of ∼29.5 ± 5.9°N at ca. 40 Ma for the southern margin of the western Qiangtang block (33.2°N, 80.9°E). A comparison of the Eocene latitudes between the western Qiangtang and Tarim block indicates a ∼ 700 km of post-40 Ma latitudinal crustal shortening between them at the longitude of ∼80°E. Our review of published Cretaceous-Paleogene paleopoles from western Tibet suggests that the western Qiangtang block was positioned at a stable latitude during ∼116–30 Ma. Our paleomagnetic compilation also indicate a discrepancy in the latitude (∼9.7 ± 4.3°) of western Lhasa and Qiangtang during the interval of 132 and 67 Ma, which vanished at ca. 30 Ma. We suggest a crustal shortening model to interpret this 1076 ± 477 km discrepancy, which was accommodated by the interior of the Lhasa block, the Bangong-Nujiang suture zone, and/or an eastward extrusion of Indochina from an original position between the Lhasa and Qiangtang blocks during ∼67–30 Ma. We conclude that the crustal shortening caused by the ongoing India-Asia collision spread progressively northwards into Asia. We emphasize that reliable paleomagnetic data from Paleocene and lower Eocene units in the western Qiangtang and Lhasa blocks have the potential to further refine these crustal shortening estimates. • We provide late Eocene paleomagnetic results from western Qiangtang. • The western Qiangtang block had a paleolatitude of 29.5 ± 5.9°N at ca. 40 Ma. • ∼700 km of post-40 Ma N-S crustal shortening between western Qiangtang and Tarim. • ∼1100 km of N-S crustal shortening between western Lhasa and Qiangtang during ∼67–30 Ma. • Crustal shortening spread progressively northwards into Asia.

Left ventricular strain in neonates using 2-dimensional speckle tracking: Normal range and relation with bi-plan ejection fraction.

Echocardiographic assessment of Left ventricular systolic function is traditionally being performed by estimation of fractional shortening (FS) and ejection fraction (EF). Speckle tracking echocardiography (STE) is a promising tool for assessment of myocardial function. The aim of this study is to evaluate the global longitudinal strain (GLS) using 2D-STE in healthy neonates to establish normal reference ranges. It is a retrospective study through an analysis of transthoracic echocardiogram of normal healthy neonates. We enrolled all neonates in our institution from January 1st, 2021 to February 28th, 2021. 2-D STE was used to assess left ventricular GLS from the apical views. 185 neonates were enrolled. Mean value for left ventricle GLS (%) was -19.9±1.2, GLS-derived EF (%) was 60.0±2.7; while the left ventricle EF by biplane Simpson's method (%) was 61.0±3. There is a good positive correlation between the Left Ventricle EF by biplane Simpson's method and EF by 2-D STE, which was statistically significant (r=.294,n=102,p=.003). Apical 4-chamber longitudinal strain and strain-derived EF is significantly correlated with GLS and bi-plan EF respectively. 2-STE is feasible technique for analyzing newborn myocardial systolic function. The normal range of GLS in neonates is not much different than reported for the pediatric. There is a good positive correlation between the Left Ventricle EF by 2-D STE and EF by biplane method.

E/I-corrected inclination shallowing in Cenozoic redbeds from the northern Tarim Basin, NW China: Possible causes and paleogeographic implications

AbstractBecause of their widespread occurrence and ability to carry stable remanence, continental redbeds in central Asia are frequently used in paleomagnetic studies. However, the paleomagnetic inclinations recorded by redbeds are much shallower than the expected values, as redbeds are usually subjected to inclination shallowing. To recognize and correct the inclinations recorded by the Cenozoic redbeds, the paleomagnetic data that were used for magnetostratigraphic studies in the Kuqa Depression, northern Tarim Basin, are reanalyzed in this study. The mean inclinations of the four groups of samples (Eocene, Oligocene, Miocene, and Pliocene) are systematically ~20° shallower than the expected values calculated from the apparent polar wander paths (APWPs) of Eurasia, indicating the presence of inclination shallowing. We apply the elongation/inclination (E/I) method to correct the inclination shallowing. The mean inclinations of the Eocene, Oligocene, Miocene, and Pliocene sediments are corrected from 40.5° to 63.1°, 41.0° to 63.8°, 42.0° to 63.8°, and 44.7° to 63.2°, within 95% confidence limits between 55.1° and 71.6°, 53.7° and 70.4°, 51.5° and 72.7°, and 52.2° and 71.3°, respectively, which are indistinguishable from the expected inclination values. Our results suggest that inclination shallowing in the redbeds of central Asia can be reasonably corrected using the E/I method, and sedimentary processes such as compaction and/or imbrication in the very early stage of burial are important causes for inclination shallowing. Paleolatitudes calculated from the E/I-corrected inclinations show that the Tarim Basin should have reached or been at least close to its current latitude since the Cretaceous. The Cenozoic crustal shortening estimate of the northern Tarim Basin is not detectible for paleomagnetic study.

Multiphase deformation of an inverted Permian deepwater rift basin: The Nong Pong Formation, Khao Khwang Fold and Thrust Belt, Thailand

• Khao Khwang Fold and Thrust Belt (KKFTB) is mixture of thrusted carbonate platforms over inverted deepwater rifts. • Nong Pong Formation affected by multiphase folding, whose structural style changes with sedimentary facies . • Estimated shortening of the KKFTB (300 km), supportive of E-W suture bisecting Indochina Terrane . The bathyal Permian Nong Pong Formation is crucial for understanding the deformation style, and amount of shortening in the E-W trending, Triassic (Indosinian Orogeny) Khao Khwang Fold and Thrust Belt. The formation was deposited in a series of marine rift basins, with carbonates forming on intervening highs. The platform carbonates are shortened by a series of dominantly north-directed thrusts. The Nong Pong Formation is extensively affected by tight to isoclinal, predominantly chevron style folding. Five major variations in stratigraphy (ranging between carbonate-dominated and shale-dominated) affect the deformation styles within the formation. Shortening locally is estimated to be up to 60% in sections up to 300 m long and is concentrated into short-wavelength (10 s m) structures. The absence of proximal slope depo-belts, and juxtaposition of carbonate platform facies with deepwater deposits suggest thrusts (some initiated as inverted normal faults) located on the basin margins have displacements of c. 10–25 km. Estimates of shortening from outcrops, and analogy with Zealandia, suggest the Nong Pong Formation was deposited in a basin up to 100 km wide. Such estimates point to a significant E-W trending seaway that bisected the Indochina Terrane. Multiple fold orientations and phases are present in the Nong Pong Formation, which are related to early mass transport events, multiple tectonic phases (Indosinian and Palaeogene), the influence of inherited trends (e.g. Permian rift basin morphology), and 3D deformation during a single tectonic phase. Deformation of the Nong Pong Formation demonstrates significant differences in structural style between ribbon continents and major continents, particularly, the Indochina ribbon continent shows the widespread inversion of rift basins across a submarine continent (similar to Zealandia) 100 s kms wide.

Kinematic vorticity, finite strain, and deformation thermometry analyses of the exhumed mylonites in the Samen ductile shear zone (Sanandaj-Sirjan Metamorphic Belt, Iran)

Quantitative microstructural investigations involving finite strain and vorticity analyses of quartz-rich mylonites provide significant information regarding the kinematic characteristics of the Samen shear zone (SSZ) within the Sanandaj–Sirjan Metamorphic Belt, Zagros Mountain of Iran. A dominant top-to-the-SE sense shear in the study area is recognized by several kinematic indicators. The results of the finite strain analyses indicate approximately plane strain deformation conditions (Rxz = 2.46–3.53). The mylonitic granitoid rocks record general-shear deformation (Wm = 0.37–0.94) associated with a spatial increase in simple-shear component (23%–78%) from W to E. In the study area, kinematic analyses indicate spatial variations of finite strain, deformation temperature, and the kinematic vorticity numbers resulted in partitioned progressive deformation. These spatial variations reveal an increase of all values towards the Samen thrust sheet. Ductile SSZ developed under greenschist-amphibolite facies metamorphic conditions (464–619 °C), as indicated by the presence of quartz, feldspar, biotite, muscovite, hornblende mineral assemblages, opening angles (OAs) of quartz c-axis fabrics and recrystallization regimes. The dynamic and kinematic characteristics of the study area were generally controlled by ongoing oblique convergence of the Afro-Arabian plate and the Iranian plateau with estimation of a horizontal shortening of ∼20–38% measured perpendicular to the boundaries of the SSZ.

Late Cenozoic thrust propagation within the Keping fold-and-thrust belt along the southern foreland of Chinese Tian Shan: Evidence from apatite (U[sbnd]Th)/He results

The Keping fold-and-thrust belt (FTB) is located along the southern foreland of the Chinese Tian Shan, consisting of 3–6 rows of E- to NE-trending thrusts. Determining the time of thrusting and folding within the Keping FTB is crucial to understand the process and characteristic of tectonic deformation along the southern Tian Shan foreland. Here, we present new deformation ages of four thrusts within the Keping FTB by using the apatite (UTh)/He thermochronometer. Based on analyses of 59 single-grain apatite (UTh)/He ages of 13 sandstone samples collected from the hanging-walls of the four thrusts, the deformation ages of two thrusts located at the northern part of the western Keping FTB were constrained to be ~12 Ma and ~ 11 Ma, respectively; while those of two thrusts located at the southern part of the eastern Keping FTB were interpreted to be ~14 Ma and ~ 13 Ma, respectively. The above deformation ages, together with previous studies, suggest that the Cenozoic deformation across the southern Tian Shan foreland initiated at ~16–12 Ma, and the propagation process of the Keping thrust system is laterally non-synchronous. Additionally, the million-year-scale crustal shortening rates of the Keping FTB were recalculated to be ~2.2–3.9 mm/yr in its western segment and ~ 1.3–3.6 mm/yr in its eastern segment, based on the new age constraints of initial tectonic deformation and published shortening estimates.

Mortalità per cause cardiovascolari e respiratorie attribuibile all'esposizione alle emissioni di una centrale a carbone: una proposta per stimare l'accorciamento individuale di vita.

the exposure to a coal-fired power plant has been shown to increase mortality both for cardiovascular and respiratory causes among an exposed cohort in comparison with a cohort of unexposed. Hazard ratios between 1.30 and 1.90 were found for cardiovascular and respiratory mortality. to estimate the individual life shortening among the exposed due to power plant emissions. survival for cardiovascular and respiratory disease in the exposed vs unexposed groups was estimated by the Kaplan-Meier method. For each gender and exposure, a fictitious cohort with a cumulative 30-year follow up was built combining three subcohorts of age at entry of 55-64, 65-74, and 75-84 years, with 10 years of follow up each. Survivals at 10 years in the 55-64-year subcohort were used as initial risks for 65-74-year subcohort; then, survivals at 10 years of the 65-74-year subcohort were used as initial risk in the 75-84-year subcohort. Eventually, 30-years cumulative follow up cohorts were obtained by gender and exposure. Individual life-shortening in people exposed was estimated as time from death of an exposed subject to the subsequent time when the unexposed cohort reached the same risk of the exposed subject at that time of the death. Here, it is proposed a method to take into account causes other than those considered. 144,018 subjects aged 55-74 years at entry of both genders belonging to the open cohort of residents of 12 municipalities (including Savona) from 2001 to 2013 in the area where the coal-fired power plant of Vado-Quiliano (Liguria Region, Northern Italy) is located. individual life shortening. after 5 years of follow up, the individual life shortening due to cardiorespiratory causes varied between 972 and 1,822 days for males and from 612 and 1,578 days among females. Taking into account other causes of death, reduces slightly (3% for males of 75 years at death) the estimate of life shortening found in this study. The comparison between the cohorts requires that the exposed and unexposed groups are comparable, except for the exposure, and that causes other than those considered are taken into account. Socioeconomic status had been found to have little effect on cause-specific death risk indicating that, at least in terms of socioeconomic status, the exposed and unexposed groups were similar. Taking into account causes other than those considered slightly reduced the found estimates (3% at age 75 in males). According to the proposal, the life-shortening for the considered causes is easy to calculate and provides an individual indicator of damage. Inferring from group statistics individual estimates could be the most controversial point of this approach. The proposed estimates are the most credible estimate of individual damage for each occurred death among the exposed people. an increased hazard ratio for a wide series of causes is equivalent to a life shortening among the exposed. A method to produce reasonable estimates of life-shortening is proposed as the effect of exposure at individual level. This approach is simple and do not require sophisticated statistical tools. It appears a promising approach for other settings.

Quantifying shortening across the central Appalachian fold-thrust belt, Virginia and West Virginia, USA: Reconciling grain-, outcrop-, and map-scale shortening

AbstractWe present a kinematic model for the evolution of the central Appalachian fold-thrust belt (eastern United States) along a transect through the western flank of the Pennsylvania salient. New map and strain data are used to construct a balanced geologic cross section spanning 274 km from the western Great Valley of Virginia northwest across the Burning Spring anticline to the undeformed foreland of the Appalachian Plateau of West Virginia. Forty (40) oriented samples and measurements of &amp;gt;300 joint orientations were collected from the Appalachian Plateau and Valley and Ridge province for grain-scale bulk finite strain analysis and paleo-stress reconstruction, respectively. The central Appalachian fold-thrust belt is characterized by a passive-roof duplex, and as such, the total shortening accommodated by the sequence above the roof thrust must equal the shortening accommodated within duplexes. Earlier attempts at balancing geologic cross sections through the central Appalachians have relied upon unquantified layer-parallel shortening (LPS) to reconcile the discrepancy in restored line lengths of the imbricated carbonate sequence and mainly folded cover strata. Independent measurement of grain-scale bulk finite strain on 40 oriented samples obtained along the transect yield a transect-wide average of 10% LPS with province-wide mean values of 12% and 9% LPS for the Appalachian Plateau and Valley and Ridge, respectively. These values are used to evaluate a balanced cross section, which shows a total shortening of 56 km (18%). Measured magnitudes of LPS are highly variable, as high as 17% in the Valley and Ridge and 23% on the Appalachian Plateau. In the Valley and Ridge province, the structures that accommodate shortening vary through the stratigraphic package. In the lower Paleozoic carbonate sequences, shortening is accommodated by fault repetition (duplexing) of stratigraphic layers. In the interval between the duplex (which repeats Cambrian through Upper Ordovician strata) and Middle Devonian and younger (Permian) strata that shortened through folding and LPS, there is a zone that is both folded and faulted. Across the Appalachian Plateau, slip is transferred from the Valley and Ridge passive-roof duplex to the Appalachian Plateau along the Wills Mountain thrust. This shortening is accommodated through faulting of Upper Ordovician to Lower Devonian strata and LPS and folding within the overlying Middle Devonian through Permian rocks. The significant difference between LPS strain (10%–12%) and cross section shortening estimates (18% shortening) highlights that shortening from major subsurface faults within the central Appalachians of West Virginia is not easily linked to shortening in surface folds. Depending on length scale over which the variability in LPS can be applied, LPS can accommodate 50% to 90% of the observed shortening; other mechanisms, such as outcrop-scale shortening, are required to balance the proposed model.

Structural interpretation of frontal folds and hydrocarbon exploration, western sulaiman fold belt, Pakistan

Abstract Seismic reflection profiles and borehole data combined with geological mapping was used to analyze foreland structures with 3-D structural variation, estimates of shortening, and kinematic evolution of western Sulaiman fold belt (SFB), Pakistan. The western SFB is interpreted with passive-roof duplex geometry. The floor thrust (decollement) is interpreted in Triassic strata rather than its inference in Precambrian-Cambrian evaporites. Whereas, the roof thrust (upper detachment) of hinterland vergence is located in Eocene Ghazij shale. Based on seismic data, the folds in the frontal duplex are interpreted as fault-propagation and fault-bend type. They are located over curved and staircase geometry of blind back thrusts. The folds-and-thrusts of EW trend show right-hand en-echelon stepping along NW-SE oriented mountain front due to drag along the western margin of the fold belt. The blind thrusts cut across the hanging-wall flat of the duplex horse with roots in base Triassic at depth of ~4–4.5 km 3D surfaces of reservoir strata show three areas of closed elliptical contours as potential prospects over blind thrusts, with maximum structural relief of ~2200 m. Shortening of 2100 (22%) and 9950 m (47%) is calculated along with thrusts in the frontal duplex with the interpretation of out-of-sequence structures. Passive roof duplex structures between foreland and hinterland vergent back-thrusts are reported from mountain belts around the world. We have identified out-of-sequence deformation in the frontal duplex with stacked structures. Identification of these features adds to our understanding of the development of mountain fronts in the context of Anderson's theory of faulting with the presence of a conjugate set of faults and foreland propagation of mountain fronts with secondary out-of-sequence deformation. Subsurface seismic data appears to be critical in their recognition for analysis of active foreland deformation and assessment of hydrocarbon plays in the fold belts.

Lithospheric Contraction on Mars: A 3D Model of the Amenthes Thrust Fault System

AbstractAmenthes Rupes is the topographic expression of a main fault belonging to a thrust fault system located parallel to the martian dichotomy boundary. A 3D forward model has been applied to the Amenthes thrust fault system, constraining fault geometries at depth, variations of slip along strike, and structural parameters controlling the formation of fault propagation folds. Our results provide a complex 3D view of the tectonic framework of the area, with implications for tectonic evolution, regional shortening distribution, and the main mechanical discontinuities in the lithosphere. The modeled fault surfaces show planar morphologies combined with listric geometries at depth. The obtained depths of faulting for the major faults of this fault system suggest a depth of the brittle‐ductile transition (at the time of formation) of 20–24 km, somewhat shallower than previous estimates for this area. A possible mechanical discontinuity located at 9.5–13 km deep can be deduced from the faulting depths of the secondary faults. The listric geometries at depth imply that slip is transmitted from the decollement, which, together with the inclusion in the model of secondary and subsidiary faults, allow us to estimate the horizontal shortening recorded in this area ranging from 2–3 km up to ~5.5 km in the southeastern part of the fault system. This range increases the previous shortening estimates in this area between ~60% and ~200%. Consequently, global shortening estimates based on global fault maps are biased by the detail of mapping, and shortening would substantially increase if secondary faults were included.

Anthropomorphic left ventricular mesh phantom: a framework to investigate the accuracy of SQUEEZ using Coherent Point Drift for the detection of regional wall motion abnormalities.

We present an anthropomorphically accurate left ventricular (LV) phantom derived from human computed tomography (CT) data to serve as the ground truth for the optimization and the spatial resolution quantification of a CT-derived regional strain metric (SQUEEZ) for the detection of regional wall motion abnormalities. Displacements were applied to the mesh points of a clinically derived end-diastolic LV mesh to create analytical end-systolic poses with physiologically accurate endocardial strains. Normal function and regional dysfunction of four sizes [1, 2/3, 1/2, and 1/3 American Heart Association (AHA) segments as core diameter], each exhibiting hypokinesia (70% reduction in strain) and subtle hypokinesia (40% reduction in strain), were simulated. Regional shortening ( ) estimates were obtained by registering the end-diastolic mesh to each simulated end-systolic mesh condition using a nonrigid registration algorithm. Ground-truth models of normal function and of hypokinesia were used to identify the optimal parameters in the registration algorithm and to measure the accuracy of detecting regional dysfunction of varying sizes and severities. For normal LV function, values in all 16 AHA segments were accurate to within . For cases with regional dysfunction, the errors in around the dysfunctional region increased with decreasing size of dysfunctional tissue.