Local Breaking Research Articles

Classification of Bone Fractures using CNN

Abstract: Bone breaks are common injury that require exact and opportune conclusion for legitimate treatment and administration. In this consider, we proposed a bone break location framework based on convolutional neural network systems (CNNs) to help radiologists within the location and classification of breaks from restorative imaging information, such as Xrays. The proposed framework points to computerize the break discovery prepare and give an effective and dependable device for restorative experts. The CNN-based break discovery framework comprises of a few key components, including picture preprocessing, include extraction, and classification. Within the preprocessing organize, the input X-ray pictures are preprocessed to upgrade picture quality and evacuate disturbance, guaranteeing ideal execution amid the consequent stages. Another, the CNN demonstrate is utilized to extricate important highlights from the preprocessed pictures. The demonstrate comprises of different convolutional layers that consequently learn and distinguish fracture-related designs and structures. To prepare the CNN demonstrate, a expansive dataset of labeled X- ray pictures with break comments is collected and utilized for show preparing. The preparing prepare includes nourishing the pictures into the arrange, optimizing the model's parameters utilizing back engendering, and iteratively altering the weights to play down the classification mistake. The prepared show is at that point assessed on a isolated test dataset to evaluate its execution in terms of exactness, affectability, specificity, and other significant measurements

Impact of discontinuous grain size distributions on the spectral energy distribution of debris disks

Context. The collisional evolution of debris disks is expected to cause the characteristic wavy pattern, that is, an under- or overabundance of particles of specific sizes, of grain size distributions. This perturbed grain size distribution potentially leaves characteristic patterns in the spectral energy distribution (SED) of the disk system. Aims. We aim to quantify and understand the specific influence of discontinuous particle size distributions on the appearance of debris disks. For this purpose, we considered dust emission models based on two different grain size distributions, namely, one with a single power law and one with a broken power law. In particular, our study is focused on the impact of an overabundance of small grains and an underabundance of medium-sized grains on the far-IR and (sub-)millimeter regime on the dust reemission radiation and the potential to constrain discontinuities in the grain size distribution from (sub-)millimeter photometric measurements of debris disks. Methods. We compared the spectral index α (Fν ∝ να) in the case of a continuous grain size distribution with that of a discontinuous grain size distribution. We performed this comparison for central stars with different spectral types and two different disk structures (e.g., slim and broad debris dust rings). Results. Within the considered parameter space, we found a characteristic difference between the spectral slopes of the SED in the different scenarios. In particular, the overabundance of small grains resulting from collisional events and thus parameters defining the outcome of disk events in debris disks is potentially observable by comparison with the SED corresponding to a grain size distribution resulting from an ideal collisional cascade. More specifically, the overabundance of small grains leads to a steeper slope in the far-IR and sub-millimeter regime, while the spectral index in the millimeter regime is hardly affected. On the other hand, the underabundance of medium-sized grains results in a slight steepening of the far-IR slope of the SED, but its primary effect is on the millimeter slope of the SED, causing it to become shallower. We also found that the impact of an overabundance of small dust particles is more pronounced than that of an underabundance of medium-sized dust particles. We also found that the difference between the spectral indices for the two different grain size distributions is largest for debris disks around brighter central stars and broader disks. However, the impact of the considered spatial distributions described by the fractional width of the disk system is weak. Our results also show that the dust composition is not the sole physical mechanism responsible for the spectral inversion observed in the far-IR to millimeter part of the SED of debris disk systems. Furthermore, the location of the spectral break is placed at different wavelength regimes if the grain size distribution is considered as a function of blowout size and stellar type.

Collisional Shaping of Nuclear Star Cluster Density Profiles

A supermassive black hole surrounded by a dense, nuclear star cluster resides at the center of many galaxies. In this dense environment, high-velocity collisions frequently occur between stars. About 10% of the stars within the Milky Way’s nuclear star cluster collide with other stars before evolving off the main sequence. Collisions preferentially affect tightly bound stars, which orbit most quickly and pass through regions of the highest stellar density. Over time, collisions therefore shape the bulk properties of the nuclear star cluster. We examine the effect of collisions on the cluster’s stellar density profile. We show that collisions produce a turning point in the density profile, which can be determined analytically. Varying the initial density profile and collision model, we characterize the evolution of the stellar density profile over 10 Gyr. We find that old, initially cuspy populations exhibit a break around 0.1 pc in their density profile, while shallow density profiles retain their initial shape outside of 0.01 pc. The initial density profile is always preserved outside of a few tenths of a parsec irrespective of initial conditions. We generalize this model to an arbitrary galactic nucleus and show that the location of the collisional break can be simply estimated from the nuclear properties. Lastly, we comment on the implications of collisions for the luminosity and color of stars in the collisionally shaped inner cluster.

Breakage of Beaded Fibers in a Polymer Matrix

Abstract Intermittent beading is a promising design strategy that enables simultaneous improvement of strength and toughness of fiber-reinforced composites. Despite the potential for amplification in mechanical properties, the failure mechanisms of beaded fiber composites are not fully understood. In this study, calculations are carried out for the breakage of beaded fibers in the polymer matrix composites. The plastic deformation of the polymer matrix and debonding of the bead–matrix, fiber–bead, and fiber–matrix interfaces are accounted for in the numerical analyses. It is found that the location of fiber break is governed by the toughness of the fiber–bead interface and fiber strength. The low toughness of fiber–bead interface promotes the emergence of break inside bead, and high fiber strength is capable of activating break outside bead. The break at the edge of bead prevails in most cases. We have further revealed that the fiber–matrix interface with high strength and enhanced toughness can give rise to large amount of fiber breaks, while low degree of fiber cracking emerges in the case of strong fiber–bead interface. For the bead–matrix interface, the intermediate interfacial strength generates a high degree of fiber breaks and low interfacial toughness suppresses fiber cracking, leading to small amount of fiber breaks. In addition, the dependence of plastic dissipation in the polymer matrix on fiber breakage is elucidated.

Chasing the Break: Tracing the Full Evolution of a Black Hole X-Ray Binary Jet with Multiwavelength Spectral Modeling

Black hole (BH) X-ray binaries (XRBs) are ideal targets to study the connection between accretion inflow and jet outflow. Here we present quasi-simultaneous, multiwavelength observations of the Galactic BH system MAXI J1820+070, throughout its 2018–2019 outburst. Our data set includes coverage from the radio through X-ray bands from 17 different instruments/telescopes, and encompasses 19 epochs over a 7 month period, resulting in one of the most well-sampled multiwavelength data sets of a BH XRB outburst to date. With our data, we compile and model the broadband spectra of this source using a phenomenological model that includes emission from the jet, a companion star, and an accretion flow. This modeling allows us to track the evolution of the spectral break in the jet spectrum, a key observable that samples the jet launching region. We find that the spectral break location changes over at least ≈3 orders of magnitude in electromagnetic frequency over this period. Using these spectral break measurements, we link the full cycle of jet behavior, including the rising, quenching, and reignition, to the changing accretion flow properties as the source evolves through its different accretion states. Our analysis shows consistent jet behavior with other sources in similar phases of their outbursts, reinforcing the idea that jet quenching and recovery may be a global feature of BH XRB systems in outburst. Our results also provide valuable evidence supporting a close connection between the geometry of the inner accretion flow and the base of the jet.

Performance of Automated Machine Learning in Predicting Outcomes of Pneumatic Retinopexy

ObjectiveAutomated Machine Learning (AutoML) has emerged as a novel tool for medical professionals lacking coding experience, enabling them to develop predictive models for treatment outcomes. This study evaluated the performance of AutoML tools in developing models predicting the success of pneumatic retinopexy (PR) in treatment of rhegmatogenous retinal detachment (RRD). These models were then compared with custom models created by ML experts. DesignRetrospective multicenter study. Population539 consecutive patients with primary RRD that underwent PR by a vitreoretinal fellow at six training hospitals between 2002 and 2022. MethodsWe used two AutoML platforms, MATLAB Classification Learner and Google Cloud AutoML. Additional models were developed by computer scientists. We included patient demographics and baseline characteristics, including lens and macula status, RRD size, number and location of breaks, presence of vitreous hemorrhage and lattice degeneration, and physicians’ experience. The dataset was split into a training (n = 483) and test set (n = 56). The training set, with a 2:1 success-to-failure ratio, was used to train the MATLAB models. Since Google Cloud AutoML requires a minimum of 1000 samples, the training set was tripled to create a new set with 1449 datapoints. Additionally, balanced datasets with a 1:1 success-to-failure ratio were created using Python. Main Outcome MeasuresSingle-procedure anatomic success rate, as predicted by the ML models. F2-scores and area under the receiver operating curve (AUROC) were used as primary metrics to compare models. ResultsThe best performing AutoML model (F2-score=0.85, AUROC=0.90; MATLAB), showed similar performance to the custom model (0.92, 0.86) when trained on the balanced datasets. However, training the AutoML model with imbalanced data yielded misleadingly high AUROC (0.81) despite low F2-score (0.2) and sensitivity (0.17). ConclusionsWe demonstrated the feasibility of using AutoML as an accessible tool for medical professionals to develop models from real-world data. Such models can ultimately aid in the clinical decision-making, contributing to better patient outcomes. However, outcomes can be misleading or unreliable if used naively. Limitations exist, particularly if datasets contain missing variables or are highly imbalanced. Proper model selection and data preprocessing can improve the reliability of AutoML tools.

Thermal examination for double diffusive MHD Jeffrey fluid flow through the space of disc and cone apparatus subject to impact of multiple rotations

Non-Fourier’s and non-Fick’s models enhance predictions of transient heat transfer and mass transport, especially in situations where local equilibrium assumptions break down. In such fluids, the deformation rate and shear stress display a natural parabolic structure. In this study, we explore the flow of a Jeffrey fluid with dual diffusions, incorporating both non-Fourier's and non-Fick's assumptions, through the gap of disk-cone devices. Four scenarios have been investigated for fluid flow and heat transformation in this work comprising of (i) both disc and cone are rotating in opposite directions (ii) both disc and cone are rotating in same direction, (iii) cone is rotating while disc remains stationary, (iv) disc is rotating while cone remains stationary. After deriving the basic equations, a set of appropriate variables is used to convert them into dimension from form. RK-4 (Runge-Kutta 4th order) technique has been employed for the solution of nonlinear equations. As the magnetic and Maxwell factors experience a notable increase, whether the disk and cone move in tandem, in opposite directions, or involve a static cone with a gyrating disk, or a static disk with a gyrating cone, the transverse velocity panels consistently exhibit retardation in all scenarios. Additionally, a noteworthy observation is made when evaluating changes in both the Nusselt number and the Sherwood number, with significantly more pronounced variations detected at the surface of the disk compared to that of the cone. There has been a 35% increase observed in the thermal flow rate with variations in the thermophoresis factor.

Analysis of control rod driving mechanism nozzle rupture with loss of safety injection at the ATLAS experimental facility using MARS-KS and TRACE

Korea Atomic Energy Research Institute (KAERI) has operated an integral effect test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), with reference to the APR1400 (Advanced Power Reactor 1400) for tests for transient and design basis accidents simulation. A test for a loss of coolant accident (LOCA) at the top of the reactor pressure vessel (RPV) had been conducted at ATLAS to address the impact of the loss of safety injections (LSI) and to evaluate accident management (AM) actions during the postulated accident. The experimental data has been utilized to validate system analysis codes within a framework of the domestic standard problem program organized by KAERI in collaboration with Korea Institute of Nuclear Safety. In this study, the test has been analyzed by using thermal-hydraulic system analysis codes, MARS-KS 1.5 and TRACE 5.0 Patch 6, and a comparative analysis with experimental and calculation results has been performed. The main objective of this study is the investigation of the thermal-hydraulic phenomena during a small break LOCA at the RPV upper head with the LSI as well as the predictability of the system analysis codes after the AM actions during the test. The results from both codes reveal that overall physical behaviors during the accident are predicted by the codes, appropriately, including the excursion of the peak cladding temperature because of the LSI. It is also confirmed that the core integrity is maintained with the proposed AM action. Considering the break location, a sensitivity analysis for the nodalization of the upper head has been conducted. The sensitivity analysis indicates that the nodalization gave a significant impact on the analysis result. The result emphasizes the importance of the nodalization which should be performed with a consideration of the physical phenomena occurs during the transient.

Failure Analyses on a Flexible Anode Cathodic Protection System in a Station.

Flexible anodes are a common form of anode ground bed for the cathodic protection of buried pipes in station areas, especially in new stations. In most cases, flexible anode ground beds could obtain uniform potential distribution and good protection. However, in the process of operation, there are also failure conditions such as anode body or cable breakage, electronic shorting between anode and pipes and other situations, resulting in poor protection. How to troubleshoot failures has become a difficult problem restricting the application of flexible anodes in actual production. In this paper, the failures of a flexible anode cathodic protection system in a station were assessed and analyzed in detail. The main reasons for the failures were the electronic shorting between the flexible anode and buried pipe in local area and the breaking of a partial flexible anode. The troubleshooting methods for two kinds of failures were explored. By measuring the potentials of both the flexible anode and pipes in different areas and the excavation test, the location of electronic shoring was determined. And through measuring the grounding resistance of the flexible anode and excavation test, the breaking location of the flexible anode was found. By repairing the failure sites, the failed system was restored to normal, which could provide guidance for the failure analyses of the flexible anode cathodic protection system.

Rhegmatogenous retinal detachment: an analysis of 2315 eyes over a six-year period

Background: Rhegmatogenous retinal detachment (RRD) is a form of retinal detachment caused by passage of fluid from the vitreous cavity into the space between the neurosensory retina and the retinal pigment epithelium via a retinal break or full-thickness defect. At our tertiary referral center, we evaluated the clinical and epidemiological features of RRD, and we herein report the frequency of related risk factors.
 Methods: In this retrospective study, we reviewed the records of patients with a final diagnosis of RRD at an academic ophthalmological referral center in Isfahan, Iran, over a six-year period. We retrieved and reviewed data from the medical records of all eligible participants, including sex, age, laterality, lens status, macular status, type of RRD, location and number of breaks, type of surgery, rate of re-operation during the first year after initial surgery, and documented clinical risk factors for RRD. Clinical risk factors were categorized as the presence of myopic refractive error, ocular trauma, history of cataract surgery, history of other ocular surgeries, history of uveitis, or undetermined.
 Results: We included 2315 eyes of 2229 patients with a mean (standard deviation [SD]) age of 51.1 (16.9) years and a male-to-female ratio of 1.8:1. The most common quadrants containing retinal breaks were the superotemporal quadrant (34.1%), inferotemporal quadrant (23.4%), and superonasal quadrant (10.7%). Macula-involved RRD was seen in 90% of eyes (n=2083 eyes). The most frequently identified risk factors were cataract surgery (32.9%) and myopia (22.3%) in adults, and myopia (35.0%) and ocular trauma (27.4%) in the pediatric group. Most eyes underwent pars plana vitrectomy (51.3%), whereas pneumatic retinopexy (0.7%) was the least commonly selected.
 Conclusions: Our results indicate that cataract surgery and myopia are the most common risk factors for RRD in adults. Myopia and ocular trauma are the most common risk factors in pediatric patients. As observed in many studies, the characteristics of the study population, including middle age, male sex, myopia, and ocular trauma, may be associated with RRD at different rates. Further population-based longitudinal studies with larger sample sizes are required to verify these preliminary observations.

Experimental study of the depressurization phenomena of supercritical carbon dioxide system

Depressurization accidents pose a significant safety concern for supercritical carbon dioxide (S–CO2) nuclear and power systems. However, due to the limited availability of system-level experiments, clear understandings of the phenomena associated with S–CO2 depressurization accidents are lacking. To address this gap, this paper conducted a series of experiments on a S–CO2 system to investigate the characteristics of depressurization accidents. Several key phenomena, including flash evaporation, transcritical transient heat transfer, fluid-thermo-structure coupling effect, and the fluid field changes in containment vessel, were identified and analyzed. Furthermore, the impact of break size and location, containment vessel, and initial system conditions on depressurization accidents was investigated. The acquired results provide crucial groundwork for establishing a Phenomenon Identification Ranking Table (PIRT) tailored to depressurization accidents in S–CO2 nuclear and power systems. This will significantly enhance the design and safety analysis of these systems.

Research on key risk chain mining method for urban rail transit operations: A new approach to risk management

To ensure the safety of urban rail transit operations and uncover the transmission dynamics of risk sources, a key risk chain mining method for urban rail transit operation is proposed. Firstly, the H-Apriori association rule algorithm is proposed for the characteristics of low frequency but high riskiness of high hazard degree risk sources in urban rail transit operation, which adds a new hazard degree evaluation index to the traditional Apriori algorithm and couples with support degree two-dimensionally to mine the strong association rules among risk sources. Secondly, we construct a weighted risk network with risk sources as network nodes and strong association rules as network edges, and propose a key risk chain mining method for urban rail transit operation based on path search theory to mine key risk chains from the weighted risk network. Finally, using the actual urban rail transit operation data of a city in China as an example, a total of 17 key risk chains are mined, and then 5 key risk sources and 8 key chain break locations are obtained by riskiness and frequency analysis of key risk chains, and control plans are proposed. The research outcomes introduce a novel approach to mining risk chains in urban rail transit operations, shedding light on the propagation mechanisms, triggering probabilities, and degrees of unsafety associated with risk sources. The results not only provide theoretical support but also offer methodological guidance for pinpointing locations of risk chain breaks and refining the control of risk sources.

Study on the Implementation Dilemma and Improvement Path Faced by Local Governments in the Context of the Policy of Citizenship of the Agricultural Transfer Population

In recent years, in order to meet the development needs of new urbanisation, the State has required all departments to make it a priority to vigorously promote the citizenship of the agricultural transfer population. However, studies have shown that local governments are still facing a number of urgent problems in the implementation of the policy. As some local governments are lagging behind in development, it is difficult for them to continue to afford the benefits arising from the inflow of the agricultural transfer population to the cities under the existing financial pressure, which has led to difficulties in the implementation of the policy and impeded the advancement of the citizenship of the agricultural transfer population. Based on the fact that there are few studies on local governments as the main body, the research adopts the literature analysis method and interdisciplinary analysis method, finds that the difficulties of local governments are mainly concentrated in the economic field, summarises the difficulties of local government departments as the main body of the implementation of relevant central government policies, and discusses how to help local government departments to break through their difficulties from the perspective of policies to promote the citizenship of the agricultural transferring population. The discussion is about how to help local government departments break through their difficulties from the policy perspective to promote the citizenship of agricultural transfer. Policy recommendations are also given to promote the improvement of policy implementation.

Drop-and-pull container drayage with flexible assignment of work break for vehicle drivers

Consideration of driver-related constraints, such as mandatory work break, in vehicle scheduling and routing is of extraordinary importance for safety driving and guaranteeing the interests of vehicle drivers. Drop-and-pull transportation is an efficient mode in container drayage services and creates interdependencies between the routes of vehicle drivers. The situation becomes even more complicated when the drivers must comply with requirements of the mandatory work break. This paper addresses a drop-and-pull container drayage problem with flexible assignment of work break. The time and location of work break for drivers can be flexibly chosen based on scheduling, routing and optimization requirements. The transportation vehicle is comprised of two parts as a tractor and a trailer. The tractor can drag at most one trailer at a time, and is separable from the trailer when executing drayage activities. The problem is formulated as a mixed-integer programming model, which is then strengthened by proposing several families of valid inequalities. To efficiently solve realistic-sized instances, a backtracking adaptive threshold accepting algorithm with a mixed-integer programming model specially coping with the assignment of work break is proposed. Mechanisms of tabu search are incorporated to enhance the searching ability of the algorithm. Experiments indicate that the proposed algorithm can efficiently handle the vehicle scheduling and routing as well as the work break assignment and outperforms the mathematical programming approach. Sensitivity analyses about different policies and varied length of the work break are also conducted with some managerial insights presented.

Prediction of LOCA’s break size and location based on random forest and Multi Tasking Deep Neural Network

This work presents an approach for predicting break size and location in nuclear power plants (NPP) loss of coolant accidents (LOCA) with or without emergency shutdown of a nuclear reactor (SCRAM). To accomplish that, a multi-tasking deep neural network (MTDNN) model is proposed. The training and validation data sets were generated on a PWR simulator at the Human-Systems Interface Laboratory (LABIHS) at Instituto de Engenharia Nuclear (IEN), Brazil. For each simulation, the time behaviors of more than a hundred state variables were recorded and a random forest (RF) algorithm was applied to select the most relevant variables. Using the set of 15 variables selected, the MTDNN model was trained and applied to a test set, in which accuracy of 97.26 % for location and relative error of about 3.77 were obtained for break sizes between 0 and 1200 cm2.

Stock markets from COVID-19 to the Russia–Ukraine crisis: Structural breaks in interactive effects panels

Financial markets are frequently exposed to a variety of crises at the national, regional, and global levels, with potentially heterogeneous effects on market performance. To make sound investment and policy choices, investors and policymakers are constantly concerned about the market's behavior during such times of extreme stress. This article explores the impact of the two recent crises—the Russian–Ukraine war and the COVID-19 pandemic—on equity markets using Karavias et al.’s (2022) panel data approach and daily data from January 2020 to April 2022. Unlike conventional panel data models, this novel technique assesses the presence and location of common structural breaks across the studied countries while accommodating unobserved heterogeneity and panel dependency. We hypothesize that the conflict's impact on global equity markets is heterogeneous and based on countries' economic-political connection or proximity to the war zone, notably among sanctioning countries (the G7) and non-sanctioning countries (the Russia-China-India triple or RIC). Our results suggest that the G7's financial markets are more sensitive to country-specific macroeconomic factors and commodity price changes during extreme market stress than those of the RIC triad. Moreover, the war has a stronger influence on the G7 stock markets through commodity prices, with a greater impact of natural gas and wheat prices for this group. These findings are consistent with the fact that markets in developed economies with an extreme reliance on commodities are more sensitive to crises and international conflicts.

The unique properties of tear film breakup process in patients with nasal unilateral pterygium.

This study found that the unique properties of tear film breakup process in eyes with pterygium, combined with ocular surface parameters, further revealed specific dynamic mechanism. It suggested that the thickness of pterygium was especially valuable in deciding the necessity of surgical management. This study aimed to explore the dynamic mechanism of tear film instability in eyes with pterygium. A paired-eye controlled cross-sectional study was conducted. Seventy-eight patients with nasal pterygium were enrolled. Fluorescein tear film breakup was observed. Several key parameters related to tear film quality were defined and analyzed, including total breakup area (mathematically derived from pixel size using MATLAB), breakup velocity, fluorescein breakup time, breakup location and pattern, tear meniscus height, score of fluorescein corneal staining, and meiboscore. With comparable tear meniscus height, score of fluorescein corneal staining, and meiboscore between paired eyes (p > 0.05), eyes with pterygium had shorter breakup time, larger breakup area, and faster breakup velocity (p < 0.05). In eyes with pterygium, a positive correlation between meiboscore and pterygium parameters including length, thickness, and size was observed (p > 0.001). As the thickness increased, difference of breakup time and area between paired eyes increased (p = 0.02 and 0.046). Eyes with pterygium had more fixed inferonasal breakup location and often presented as dimple break (60%), whereas random break was the most common in contralateral normal eyes (62%). A unique breakup pattern named pterygium-induced local dimple break was found. It displayed as an irregular but vertical line-like shape appearing after lipid layer spreading, which was adjacent to the lower margin of pterygium and presented with unique properties including inferonasal breakup location, local breakup area, shorten breakup time, and faster breakup velocity. Eyes with pterygium showed a unique tear film breakup process and novel breakup pattern named pterygium-induced local dimple break . Dynamic mechanism played a significant role in tear film instability of eyes with pterygium rather than aqueous deficiency and increased evaporation.

Yang–Mills–Stueckelberg theories, framing and local breaking of symmetries

We consider Yang–Mills theory with a compact structure group [Formula: see text] on a Lorentzian 4-manifold [Formula: see text] such that gauge transformations become identity on a submanifold [Formula: see text] of [Formula: see text] (framing over [Formula: see text]). The space [Formula: see text] is not necessarily a boundary of [Formula: see text] and can have dimension [Formula: see text]. Framing of gauge bundles over [Formula: see text] demands introduction of a [Formula: see text]-valued function [Formula: see text] with support on [Formula: see text] and modification of Yang–Mills equations along [Formula: see text]. The fields [Formula: see text] parametrize non-equivalent flat connections mapped into each other by a dynamical group [Formula: see text] changing gauge frames over [Formula: see text]. It is shown that the charged condensate [Formula: see text] is the Stueckelberg field generating an effective mass of gluons in the domain [Formula: see text] of space [Formula: see text] and keeping them massless outside [Formula: see text]. We argue that the local Stueckelberg field [Formula: see text] can be responsible for color confinement. We also briefly discuss local breaking of symmetries in gravity. It is shown that framing of the tangent bundle over a subspace of spacetime makes gravitons massive in this subspace.

Opposing genetic patterns of range shifting temperate and tropical gastropods in an area undergoing tropicalisation

AbstractAimThe poleward range expansion of tropical species, and range contraction of temperate species (known as tropicalisation) has mainly been studied from an ecological perspective, with little research on its genetic consequences. Here, we used distributional and genetic data to document the consequences of tropicalisation in rocky shore gastropods and assess more broadly the future implications of tropicalisation on phylogeographic patterns.LocationNineteen sampling sites along &gt;3000 km of the eastern Pacific rocky intertidal zone, from the tip of the Baja California Peninsula to southern California.TaxonTemperate gastropods: Lottia conus, L. strigatella, Fissurella volcano and Tegula gallina.Tropical gastropods: Fissurella rubropicta, Nerita funiculata and N. scabricosta.MethodsWe determine historical and modern distributions of tropical and temperate species by combining historical records with current field surveys. Using a section of the cytochrome oxidase subunit I gene, we utilised comparative phylogeography, analysis of molecular variance, FST pairwise comparison, mismatch distributions of haplotype differences and neutrality tests to detect genetic signatures of tropicalisation and to better understand its consequences.ResultsWe identified range contractions in two temperate species and range expansion in all three tropical species. We detected genetic signatures of range expansion in the tropical species through unimodal distributions of pairwise haplotype differences and strongly negative values for the Fu and Li D and F* statistics. We found population subdivision and phylogeographic breaks in three temperate species, although the geographic location of the breaks differed among species.Main ConclusionsGenetic signatures and field surveys indicate recent range expansions in tropical species, supporting tropicalisation along the studied coastline. Conversely, we found phylogeographic breaks in temperate species, suggesting that tropicalisation may cause genetic erosion of evolutionary distinct lineages with range‐contraction. The different locations of the phylogeographic breaks among temperate species suggests that some barriers are species specific.

Contagious Dishonesty: Corruption Scandals and Supermarket Theft

Is dishonest behavior contagious? We answer this question by studying whether corruption scandals affect the propensity of supermarket customers to steal while using a self-service checkout system. Crucially, this system allows shoppers to engage in dishonest behavior by underreporting the value of their shopping cart. Exploiting data from random audits on shoppers, we show that the probability of stealing increases by 16 percent after a local corruption scandal breaks. This effect is not driven by any change in material incentives. Suggestive evidence shows that it is driven by a reduction in the self-imposed cost of stealing. (JEL D12, D73, D91, K42, L81, Z13)