Stationary Periods Research Articles

Temperature conditions during commercial transportation of cull sows to slaughter

Management of ambient temperature is central in sow production, but temperature in commercial trucks transporting sows has only received limited scientific focus. We aimed to describe temperature inside trucks depending on season and on shifts in state of the trucks (‘non-stationary’, ‘stopped’, ‘waiting’) transporting sows (up to 8 h) to slaughter. Temperature outside the trucks was described during the last part of the journeys, and compared with temperature inside the trucks. Data were collected during 12 months and included 39 commercial journeys. We measured temperature (°C) inside trucks every minute in one compartment holding sows at commercial density. Data for temperature outside the trucks were collected from an official weather station near the slaughterhouse. Mean journey duration was 233 ± 114 min (range 47–470 min). From GPS-data, 26 of the journeys involved at least one stop lasting 5 min or more. Stops had a mean duration of 14 ± 8 min (range 5–40 min). Mean temperature inside trucks during journeys was 13.8 ± 5.3 °C (3.3–26.0), and differed between seasons. During journeys, temperature inside trucks increased during stationary periods. When compared to the outside temperature during 10 min before arriving at the slaughterhouse, and in the first 10 min of waiting after arrival, the mean temperature difference between inside and outside the truck ranged from 3 to 7 °C.The results suggest that in a moderate climatic zone like Denmark, temperature in trucks transporting sows to slaughter was not maintained within the thermal comfort zone of sows, and increased during stationary periods. This may have adverse consequences in terms of animal welfare. Future studies of optimization of transport management, ventilation and logistics are needed to examine possibilities to maintain temperatures in the comfort zone.

Six pelagic seabird species of the North Atlantic engage in a fly-and-forage strategy during their migratory movements

Bird migration is commonly defined as a seasonal movement between breeding and non-breeding grounds. It generally involves relatively straight and directed large-scale movements, with a latitudinal change, and specific daily activity patterns comprising less or no foraging and more traveling time. Our main objective was to describe how this general definition applies to seabirds. We investigated migration characteristics of 6 pelagic seabird species (little auk Alle alle, Atlantic puffin Fratercula arctica, common guillemot Uria aalge, Brünnich’s guillemot U. lomvia, black-legged kittiwake Rissa tridactyla and northern fulmars Fulmarus glacialis). We analysed an extensive geolocator positional and saltwater immersion dataset from 29 colonies in the North-East Atlantic and across several years (2008-2019). We used a novel method to identify active migration periods based on segmentation of time series of track characteristics (latitude, longitude, net-squared displacement). Additionally, we used the saltwater immersion data of geolocators to infer bird activity. We found that the 6 species had, on average, 3 to 4 migration periods and 2 to 3 distinct stationary areas during the non-breeding season. On average, seabirds spent the winter at lower latitudes than their breeding colonies and followed specific migration routes rather than non-directionally dispersing from their colonies. Differences in daily activity patterns were small between migratory and stationary periods, suggesting that all species continued to forage and rest while migrating, engaging in a ‘fly-and-forage’ migratory strategy. We thereby demonstrate the importance of habitats visited during seabird migrations as those that are not just flown over, but which may be important for re-fuelling.

MINIATURE GPS DATA LOGGERS REVEAL HABITAT AFFILIATIONS AND MOVEMENT OF VEERY (CATHARUS FUSCESCENS) DURING THEIR FIRST NON-TRANSIENT PERIOD IN SOUTH AMERICA

The ecology of Nearctic-Neotropical migrant songbirds in South America is largely unexplored. We used miniature global positioning system (GPS) data loggers to determine the broad habitat associations of nine Veeries (Catharus fuscescens) during their first non-transient period in South America. Because Veeries undertake an intratropical migration between two separate non-transient periods, the habitat used by settled birds in South America cannot not be determined from field observation or the capture of single unmarked individuals. Using satellite images, we examined coarse habitat characteristics at GPS positions from the tagged birds during their first non-transient period (December – February). We also examined habitat descriptions from existing records (e.g., published literature, museum records) of multiple birds from single sites that we consider settled individuals. All records we accepted as birds settled during their first non-transient period, including birds we tagged, were associated with stunted forest on nutrient poor soils primarily on elevated cerrado and white sand enclaves (~200 – 750 m) on the Brazilian Shield in southern Amazonia (cerrado, cerradão, savana metalófita – canga, campinarana, sartenejal). Notably, these uncommon forest communities are geographically limited and severely threatened due to anthropogenic conversion. Therefore, because of restricted habitat availability and the species’ recent population decline, we believe the Veery’s current global conservation status should be reconsidered. Following Nearctic-Neotropical migration, tagged individuals exhibited three behaviors prior to intratropical migration: (1) a prolonged stationary period at a single site, (2) shorter stationary periods with relocation events, (3) apparent continual movement. Our results have significant importance in terms of understanding the ecology and conservation needs of this declining species and demonstrate the utility of GPS loggers in tracking songbirds through dense tropical vegetation in remote and inaccessible regions of South America.

Changes in precipitation rates over the last 70 years in Eastern Paraná State, Brazil

Temporal hydrometeorological series may present variations over time. The awareness of these characteristics is important to improve the monitoring of changes that these series may suffer along time. In this regard, the present paper aims to identify the existence of precipitation trends for the east portion of Paraná state, in Brazil, and also investigate the changes in the observed rates over the last 70 years. The statistical tests of Mann-Kendall and Pettitt, and also the Theil-Sen estimator, are applied for series of precipitation from 13 pluviometric stations of eastern Paraná state, Brazil, with 70 years of data records. By the results it was identified long-term linear positive trend for 11 of the precipitation series and also detected medium-term patterns in precipitation over 10 stations, characterizing the Joseph effect. These series have presented a behavior with higher rates in the most recent years in comparison from the first years of the historical data, sectioning the complete series into two shorter stationary periods, and presenting an abrupt change point.

A wearable light-touch contact device for human balance support

There is an urgent need for the development of ways to address the major issue of falls among today’s globally aging population. The authors here outline a new approach referred to as virtual light-touch contact to mitigate postural sway during ambulatory and stationary periods, and propose a wearable light-touch (WLT) system featuring a virtual partition around the user that allows determination of virtual forces resulting from related contact. The data produced are used to create vibrotactile fingertip feedback, which supports comprehensive perception of the partition. Non-impaired subjects were recruited to support evaluation of the prototype system (incorporating tactile stimulation and motion-capture technology), with outcomes showing successful mitigation of postural sway in a heel-to-toe tandem stance. Research performed with 150 able-bodied volunteers to validate the performance of the new set-up (incorporating an acceleration sensor and a voice coil motor to render the light-touch effect) suggested that the proposed WLT approach supports human balance on a level comparable to that of the light-touch effect.

Differential survival throughout the full annual cycle of a migratory bird presents a life-history trade-off.

Long-distance migrations are among the most physically demanding feats animals perform. Understanding the potential costs and benefits of such behaviour is a fundamental question in ecology and evolution. A hypothetical cost of migration should be outweighed by higher productivity and/or higher annual survival, but few studies on migratory species have been able to directly quantify patterns of survival throughout the full annual cycle and across the majority of a species' range. Here, we use telemetry data from 220 migratory Egyptian vultures Neophron percnopterus, tracked for 3,186 bird months and across approximately 70% of the species' global distribution, to test for differences in survival throughout the annual cycle. We estimated monthly survival probability relative to migration and latitude using a multi-event capture-recapture model in a Bayesian framework that accounted for age, origin, subpopulation and the uncertainty of classifying fates from tracking data. We found lower survival during migration compared to stationary periods (β=-0.816; 95% credible interval: -1.290 to -0.318) and higher survival on non-breeding grounds at southern latitudes (<25°N; β=0.664; 0.076-1.319) compared to on breeding grounds. Survival was also higher for individuals originating from Western Europe (β=0.664; 0.110-1.330) as compared to further east in Europe and Asia, and improved with age (β=0.030; 0.020-0.042). Anthropogenic mortalities accounted for half of the mortalities with a known cause and occurred mainly in northern latitudes. Many juveniles drowned in the Mediterranean Sea on their first autumn migration while there were few confirmed mortalities in the Sahara Desert, indicating that migration barriers are likely species-specific. Our study advances the understanding of important fitness trade-offs associated with long-distance migration. We conclude that there is lower survival associated with migration, but that this may be offset by higher non-breeding survival at lower latitudes. We found more human-caused mortality farther north, and suggest that increasing anthropogenic mortality could disrupt the delicate migration trade-off balance. Research to investigate further potential benefits of migration (e.g. differential productivity across latitudes) could clarify how migration evolved and how migrants may persist in a rapidly changing world.

A rare 300 kilometer dispersal by an adult male white-tailed deer.

Despite the key roles that dispersal plays in individual animal fitness and meta‐population gene flow, it remains one of the least understood behaviors in many species. In large mammalian herbivores, dispersals might span long distances and thereby influence landscape‐level ecological processes, such as infectious disease spread. Here, we describe and analyze an exceptional long‐distance dispersal by an adult white‐tailed deer (Odocoileus virginianus) in the central United States. We also conducted a literature survey to compare the dispersal to previous studies. This dispersal was remarkable for its length, duration, and the life history stage of the dispersing individual. Dispersal is typical of juvenile deer seeking to establish postnatal home ranges, but this dispersal was undertaken by an adult male (age = 3.5). This individual dispersed ~300 km over a 22‐day period by moving, on average, 13.6 km/day and achieving a straight‐line distance of ~215 km, which was ~174 km longer than any other distance recorded for an adult male deer in our literature survey. During the dispersal, which occurred during the hunting season, the individual crossed a major river seven times, an interstate highway, a railroad, and eight state highways. Movements during the dispersal were faster (mean = 568.1 m/h) and more directional than those during stationary home range periods before and after the dispersal (mean = 56.9 m/h). Likewise, movements during the dispersal were faster (mean = 847.8 m/h) and more directional at night than during the day (mean = 166.4 m/h), when the individual frequently sheltered in forest cover. This natural history event highlights the unpredictable nature of dispersal and has important implications for landscape‐level processes such as chronic wasting disease transmission in cervids. More broadly, our study underscores how integrating natural history observations with modern technology holds promise for understanding potentially high impact but rarely recorded ecological events.

Seasonal variation in habitat selection for a Neotropical migratory songbird using high‐resolution GPS tracking

AbstractDeciphering how environmental heterogeneity affects population dynamics in migratory species is complicated by the redistribution of individuals in time and space across the annual cycle. Approaches that tackle this problem require information about how migratory species respond to ecological factors across time and space, and how they are linked across migratory periods. Using high spatial resolution (10 m) GPS tracking of individual male songbirds, we quantified for the first time (1) local‐ and landscape‐scale habitat selection across the annual cycle and (2) patterns indicative of regional habitat selection for individuals within five populations of wood thrush (Hylocichla mustelina) throughout their breeding range. Wood thrush exhibited seasonal variation in local‐ and landscape‐scale habitat selection. Within stationary periods, wood thrush occupied forested habitats and proximity to forest edge was an important predictor of habitat selection at the local scale. In contrast, during migratory periods wood thrush exhibited greater behavioral flexibility indicative of a more generalist approach to habitat selection. Landscape habitat selection was only identified during the breeding season (average patch size) and could be a response to the extensive forest fragmentation in the North American breeding grounds. We also identified individual population distribution patterns indicative of regional habitat selection during fall migration and winter period, but not spring migration. Seasonal changes in habitat selection at multiple spatial scales suggest the factors driving habitat selection patterns are aligned with life‐history stage and may be dependent on regional differences in landscape composition. These results highlight the importance of a full annual cycle approach to ecological studies that address how migratory species respond to spatial and temporal environmental heterogeneity.

Positional running capacities and in-game demands of South African university level rugby players

Rugby is a complex contact sport consisting of varying intensities of locomotion, interspersed with stationary and contact periods. An increasing professionalisation of the sport even at university and school level has engendered a growing need to collect objective data regarding the physical attributes of rugby players. The aim of the study was to assess the positional running capacities and demands of university rugby players. Twenty-nine male rugby players (age: 22.5 ± 1.2 years; body mass: 96.1 ± 13.26 kg; stature: 182.6 ± 7.5 cm) completed a battery of tests, which included: 10 m + 40 m sprint, yo-yo intermittent recovery (Yo-Yo IRT), repeated sprint ability test (RSA), and had their in-game running demands evaluated. Positional differences between forwards and backs were reported (p<0.05) for Yo-Yo IRT: 19.2 ± 2 vs 21.1 ± 2; 10 m sprint: 1.7 ± 0.1s vs 1.6 ± 0.0s; 40 m sprint test: 5.4 ± 0.3s vs 5.1 ± 0.1s; 5 m RST: 738.9 ± 31.1m vs 767.3 ± 20.9m. Additionally, a significant difference in-game distances between forwards and the backs (absolute: 5564.1 ± 842.5m vs 6955.9 ± 780.9m; relative: 54.7 ± 9.0 m.min-1 vs 60.6 ± 8.7m.min-1) were obtained. The assessment of university-level rugby players showed that backline players tend to record higher aerobic capacity, acceleration and sprint values than forwards. Evidence has shown that during matches, backs tend to cover more distance and spend more time in each speed band than forwards. The findings were discussed in the light of their implications for competitive rugby performance.

First Graders' Stationary Behavior in Norwegian After-School Programs: A Mixed Methods Investigation.

After-school programs (ASPs) might influence the activities and behaviors of children. The aim of the reported study was to investigate how stationary behavior unfolds during ASP time in a sample of Norwegian first graders. A total of 42 first graders from 14 ASPs were observed during one entire ASP day. ActiGraph accelerometers were used to measure the intensity of their physical activity (PA). Children were found to be involved in stationary behavior for 54.9% of the studied ASP time—a median of 79.5 min (IQR = 62.0). However, there was considerable variation among the children in the sample. Most stationary behavior—63.5% of all stationary behavior during ASP time—was accumulated when the children were sitting indoors. The proportion of stationary behavior was significantly higher indoors than outdoors, during adult-managed time than child-managed time, and during time spent together with other children than time spent alone (p < 0.05). In child-managed physical activity play outdoors, stationary behavior commonly occurred during short periods of standing still. Stationary behavior was usually rapidly broken up by longer periods of PA. Stationary periods involved activities in close relationship with other children and appeared to be important for social interaction and friendship building. The researchers suggest that ASP staff members should actively promote physical activity play that breaks up sedentary time and replaces some stationary behaviors with PA, especially among the least active children.

Practical server-side WiFi-based indoor localization: Addressing cardinality & outlier challenges for improved occupancy estimation

Server-side WiFi-based indoor localization offers a compelling approach for passive occupancy estimation (i.e., without requiring active participation by client devices, such as smartphones carried by visitors), but is known to suffer from median error of 6–8 meters. By analyzing the characteristics of an operationally-deployed, WiFi-based passive indoor location system, based on the classical RADAR algorithm, we identify and tackle 2 practical challenges for accurate individual device localization. The first challenge is the low-cardinality issue, whereby only the associated AP generates sufficiently frequent RSSI reports, causing a client to experience large localization error due to the absence of sufficient measurements from all nearby APs. The second is the outlier resolution issue, whereby clients physically located outside the fingerprinted region but attached to the WiFi network are localized erroneously to a fingerprinted landmark. To tackle the low-cardinality challenge, we identify the stationary-period of devices, and augment the device’s live AP-reported RSSI readings, during such stationary periods, with the useful but ‘stale’ values reported by neighboring APs. To eliminate extraneous outlier devices, we apply a threshold-based filtering strategy, where the RSSI thresholds for all interior points are derived using a combination of a weighted path-loss propagation model and the Voronoi tessellation of the fingerprinting map. In addition, to overcome intermittent false positives/negatives in localization or subsequent occupancy estimation, we apply two additional techniques: (a) temporal smoothing of location estimates over a time period, and (b) identification and removal of static devices. We experimentally evaluate these combined set of techniques on 3 different indoor work, collaboration & residential spaces, and show how these techniques improve the robustness of location tracking, which subsequently translates into an approx. 80+% reduction in the overall occupancy estimation error.

Integrating season-specific needs of migratory and resident birds in conservation planning

Efforts to conserve migratory species have been challenged by a poor understanding of their temporally-dynamic distributions over large geographies. Consequently, most conservation plans have focused on the stationary periods despite the importance of migratory periods for overall population dynamics and fitness. Strategies that identify stopover sites for migratory species during migration and examine the potential for those sites to protect resident species may offer an efficient approach to enhance the conservation of both groups. Using crowd-sourced data (i.e., eBird), we identified priority stopover sites (PSSs) that target protection of 30% of the seasonal average abundance of over 400 Nearctic-Neotropical migratory bird species in the Americas during spring and fall migratory periods. We then calculated the proportion of global abundance of 158 resident bird species including 27 imperiled species, that were captured on those sites, analysed the extent to which sites were protected, and forecast changes in land use. Around half or less of PSSs were shared between spring (52–54%) and fall (23–32%), indicating that planning efforts should be season-specific. Less than 10% of PSSs were protected, while 30–46% were in human modified landscapes. Even though our spatial algorithms targeted 30% of the abundance of migratory birds, comparable proportions of resident bird populations were also captured (36% of resident and 42% of imperiled bird populations in fall, 22% and 31% respectively in spring). Our findings demonstrate that protecting stopover sites for migrating species can provide co-benefits for resident and imperiled species.

An experimental test of stationary lay-up periods and simulated transit on biofouling accumulation and transfer on ships

Biofouling accumulation on ships’ submerged surfaces typically occurs during stationary periods that render surfaces more susceptible to colonization than when underway. As a result, stationary periods longer than typical port residence times (hours to days), often referred to as lay-ups, can have deleterious effects on hull maintenance strategies, which aim to minimize biofouling impacts on ship operations and the likelihood of invasive species transfers. This experimental study tested the effects of different lay-up durations on the magnitude of biofouling, before and after exposure to flow, using fouling panels with three coating treatments (antifouling, foul-release, and controls), at two sites, and a portable field flume to simulate voyage sheer forces. Control panels subjected to extended stationary durations (28-, 45- and 60-days) had significantly higher biofouling cover and there was a 13- to 25-fold difference in biofouling accumulation between 10-days and 28-days of static immersion. Prior to flume exposure, the antifouling coating prevented biofouling accumulation almost entirely at one site and kept it below 20% at the other. Foul-release coatings also proved effective, especially after flume exposure, which reduced biofouling at one site from >52% to <6% cover (on average). The experimental approach was beneficial for co-locating panel deployments and flume processing using a consistent (standardized) flow regime on large panels across sites of differing conditions and biofouling assemblages. While lay-ups of commercial vessels are relatively common, inevitable, and unavoidable, it is important to develop a better understanding of the magnitude of their effects on biofouling of ships’ submerged surfaces and to develop workable post-lay-up approaches to manage and respond to elevated biofouling accumulation that may result.

Determining Stationary Periods across Multiple Sensors: An Application to Observed Canopy Turbulence Response to Atmospheric Stability

AbstractA recently proposed multisensor stationarity analysis technique (MSATv1) is improved to eliminate the initial interrogation of time-averaged wind directions, a redundant and potentially biasing procedure for a technique capable of detecting changes in mean wind directions. The new technique, MSATv2, satisfies two basic expectations that are not guaranteed in MSATv1: 1) a nonstationary event should not belong to any stationary interval identified with a given stringency, and 2) nonstationary events identified with an arbitrary stringency should continue to be identified as nonstationary with increasing stringency. These expectations are confirmed by applying MSATv2 to two long periods, during the defoliated phase of the Canopy Horizontal Array Turbulence Study (CHATS), whose durations are determined solely by data availability. MSATv2 successfully determines visually trivial and nontrivial nonstationary transitions, uncovering details of the time evolution of dynamic processes. MSATv2 yields ensemble-average estimates of mean wind speeds and directions with well-controlled and quantifiable uncertainties for atmospheric stability conditions ranging from near neutral to free convection. These results enable interrogation of the observed canopy turbulence response to atmospheric stability in isolation from contamination by spatial variation with position relative to canopy elements. MSATv2 results also reveal the connection between the presence of organized convective structures and variability in mean shear, showing the role of organized convective structures in the observed relationship between the bulk drag coefficient and atmospheric instability.

Experiences and opinions of Danish livestock drivers transporting sows regarding fitness for transport and management choices relevant for animal welfare.

Including Denmark, modern pig production typically involves annual culling rates close to 50%. One important professional group in this process are livestock drivers transporting the animals to slaughter. By use of oral interviews, we aimed to describe experiences and opinions of Danish livestock drivers transporting sows, regarding fitness for transport and management choices relevant for animal welfare. All livestock drivers (N = 30) associated with a large slaughterhouse in Denmark accepting sows were approached in person, after having unloaded sows, and asked questions by an interviewer. A total of 22 livestock drivers (73%) answered all questions, constituting of a heterogeneous group of men of varying age, level of experience, time since they achieved the legally required certificate of competence, and daily involvement in sow transportation. Among livestock drivers included in the present study, doubt about fitness for transport was not uncommon, and specific reasons underlying their doubt were listed. All respondents reported to have experienced having to reject loading a cull sow who had been selected for slaughter by a herd manager, and approximately 40% did this several times a year. In contrast, almost 50% had never experienced having a sow rejected by the veterinarian at the slaughterhouse due to lack of fitness for transport. When asked about their management of sows during transportation, the majority (71%) reported using special condition transport (use of extra bedding and partitions to separate individual sows from rest of the load) less than once per month. All respondents considered hot days a problem for welfare of sows and the majority reported to adjust air intake of trucks daily or several times per week. In addition, approximately half of the respondents mentioned stationary periods (e.g., mandatory driver rests) as a challenge to sow welfare, to a degree where they had violated regulation on mandatory driver rests for the sake of welfare of the sows. The present study is among the few to focus on livestock drivers transporting sows, including questions about management choices and the animals’ fitness for transport. The findings may form basis for future development of educational programs for drivers as well as for the formulation of hypotheses for future studies in this area, characterized by complicated underlying legislation and challenges to animal welfare.

Pose and velocity estimation for soccer robots

This paper details the design and real-time implementation of a planar state estimator for soccer robots. A camera system, encoders, gyroscope and accelerometer are combined in a two-stage Kalman filter through a constant acceleration model. Inflating Noise Variance is employed to handle slip and ensure convergence in stationary periods. The approach oers substantial improvement w.r.t. the old pose estimator.

Analysis of the impacts of atmospheric circulation patterns on the regional air quality over the geographical center of the Eurasian continent

There is growing scientific interest in the impact of atmospheric circulation on regional air quality; however, it is poorly studied in Central Asia. This study is the first assessment of the evidence-based relations between air pollution episodes and the elementary circulation mechanisms (ECMs, by the classification from Dzerdzeevskii et al.) with atmospheric blocking process effects on an urban atmosphere over the geographical center of the Eurasian continent. The capital city of Kazakhstan, Nur-Sultan, is selected as the study location since it is located in the north of the Kazakh Uplands in a dry steppe zone. First, an episode identification procedure using multiple stations and multiple-pollutant time series data is proposed. After the identification of the aggregated pollutant episodes during the heating and non-heating periods in 2017, their relations with blocking anticyclones and cyclones are further investigated by checking the reversal of meridional gradients in the 500 hPa and 850 hPa geopotential height (GPH) maps. In total, 12 and 9 pollution episodes lasting an average of 5 days were identified in heating and non-heating periods, respectively. Following the calendar of continuous ECM changes, the type of ECM is determined for each episode, and then, the types of ECMs with atmospheric circulation and trajectory characteristics corresponding to the episodes were analyzed in detail. The findings suggest that i) regional and local air pollution levels on the Eurasian Steppes are actively controlled by regional meteorological variations, ii) the northern streams of cold Arctic air spread to the region and Siberian anticyclone reaches in winter, leading to extreme negative air temperature anomalies that contribute to the further cooling of the Arctic air and formation of extensive stationary anticyclones with blocking effects over the region, iii) a cold season circulation type, ECM 13w, was one of the most dominant ECMs with approximately 23% annual prevalence causing 30% of all the episodes, iv) ECMs 11a, 5a, and 5b were also associated with much higher pollution levels (up to 4-fold increases over the annual average), but they had lower prevalences (up to 5%). As a result, it was demonstrated that the regional climate conditions with particular ECMs regulate the ventilation characteristics of the atmosphere over the study area, and local air pollution concentrations increase to extreme levels and remain there longer, particularly during stationary anticyclone periods.

The dynamic relationship between internet attention and stock market liquidity: A thermal optimal path method

Financial theory holds that attention plays a significant role in the information response, and internet attention has been used widely to explore their influence on stock market microstructure. Based on the thermal optimal path method and social network data, this paper constructs two dynamic variables including investor and media attention reflecting the internet attention and examines the lead–lag relationship between the internet attention and market liquidity measures. Furthermore, the sample is further divided into three parts including stationary and fluctuation periods to explore the predictive ability of internet attention effects on Chinese stock market liquidity. The main results reveal that the lead–lag orders between the internet attention and market liquidity are not always positive or negative. In other words, the internet attention does not always dominate the stock market liquidity, and vice versa. Moreover, there are significant differences in the results of lead–lag orders between three different subsample periods. The empirical results confirm that internet attention facilitates forecasting market performance in the Chinese stock market, and supplements the relevant theories of stock market trading and behavioral finance from the perspective of econophysics.

Erosion–corrosion behavior of SAF3207 hyper-duplex stainless steel

Polarization curves and mass losses of SAF3207 hyper-duplex stainless steel under various conditions were measured. The damaged surfaces after erosion–corrosion tests were characterized by scanning electron microscopy. The results showed that an increase in flow velocity could enhance the electrochemical corrosion and consequently decrease the passivation properties of the steel. The erosion–corrosion damage of the samples increased substantially when the flow velocity exceeded the critical value of 4 m·s−1. The mass loss rate increased as the sand content increased, reaching a maximum at 7wt% sand content, corresponding to the most severe electrochemical corrosion damage. When the sand content was increased further, however, the mass loss rate decreased and then tended stable. The mass loss was divided into incubation, sustained, and stationary periods, with a maximum mass loss rate of 12.97 g·h−1·m−2 after an erosion period of 2.5 h. The erosion–corrosion mechanism was investigated in detail.

Wind-associated detours promote seasonal migratory connectivity in a flapping flying long-distance avian migrant.

It is essential to gain knowledge about the causes and extent of migratory connectivity between stationary periods of migrants to further the understanding of processes affecting populations, and to allow efficient implementation of conservation efforts throughout the annual cycle. Avian migrants likely use optimal routes with respect to mode of locomotion, orientation and migration strategy, influenced by external factors such as wind and topography. In self-powered flapping flying birds, any increases in fuel loads are associated with added flight costs. Energy-minimizing migrants are therefore predicted to trade-off extended detours against reduced travel across ecological barriers with no or limited foraging opportunities. Here, we quantify the extent of detours taken by different populations of European nightjars Caprimulgus europaeus, to test our predictions that they used routes beneficial according to energetic principles and evaluate the effect of route shape on seasonal migratory connectivity. We combined data on birds tracked from breeding sites along a longitudinal gradient from England to Sweden. We analysed the migratory connectivity between breeding and main non-breeding sites, and en route stopover sites just south of the Sahara desert. We quantified each track's route extension relative to the direct route between breeding and wintering sites, respectively, and contrasted it to the potential detour derived from the barrier reduction along the track while accounting for potential wind effects. Nightjars extended their tracks from the direct route between breeding and main non-breeding sites as they crossed the Mediterranean Sea-Sahara desert, the major ecological barrier in the Palaearctic-African migration system. These clockwise detours were small for birds from eastern sites but increased from east to west breeding longitude. Routes of the tracked birds were associated with partial reduction in the barrier crossing resulting in a trade-off between route extension and barrier reduction, as expected in an energy-minimizing migrant. This study demonstrates how the costs of barrier crossings in prevailing winds can disrupt migratory routes towards slightly different goals, and thereby promote migratory connectivity. This is an important link between individual migration strategies in association with an ecological barrier, and both spatially and demographic population patterns.