Search

The development of autonomous detection technology is imperative in the field of construction. The bucket fill factor is one of the main indicators for evaluating the productivity of construction vehicles. Bucket detection is a prerequisite for bucket trajectory planning. However, previous studies have been conducted under ideal environments, a specific single environment, and several normal environments without considering the actual harsh environments at construction sites. Therefore, seven extreme environments are set in this paper to fill this gap, and an effective method is proposed. First, a novel framework for image restoration under extreme environments is proposed. It applies to all tasks conducted by vision on construction sites. Second, a combination of segmentation and classification networks is used for the first time in this area. Multitask learning is used to discover a positive correlation between fill factor estimation and bucket detection. Furthermore, probabilistic methods and transfer learning were introduced, and excellent results were achieved (97.40% accuracy in fill factor estimation and 99.76% accuracy in bucket detection for seven extreme environments). [ABSTRACT FROM AUTHOR]

New considerations of the stability problem of dewetting, as addressed in the initial paper [Cryst. Res. Technol. , 491 (2004)], show that, in the most general case, when dewetting occurs in microgravity it is necessarily stable. This explains why the phenomenon has been observed so many times during solidification of semiconductors in space. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

The diversity of flood‐generating mechanisms superimposed on catchment physiographic features with non‐stationary meteorological drivers makes future flood hazard assessment a grand challenge. To date, many studies have examined patterns in rainfall and streamflow, but far fewer have investigated trends in the other drivers of flooding. The complex transfer function between precipitation and flooding makes it potentially misleading to simply look at the change in rainfall to express the hazard. Furthermore, there are very few studies that have directly used output from km‐scale climate models in flood modeling. Coarse resolution climate data sets may not credibly resolve local climate and weather extremes. Changes in rainfall distribution and antecedent moisture over extended time periods due to climate change have so far been ignored when assessing urban pluvial flood risk. In this paper, an urban flood hazard assessment framework using the latest 2.2 km resolution UK Climate Projections Local is proposed. Global warming induced changes in pluvial flood risks under RCP8.5 are projected, focusing on the impact of changing precipitation patterns and soil moisture dynamics on flood generation. Results indicate a strong increase in the frequency of occurrence of extreme floods, and the resultant future (2060–2080) annual flood volume is expected to increase up to 52.6% relative to 1980–2000 over a major UK urban region, and these patterns are likely to hold more generally elsewhere in the UK. Shifts to a later occurrence of extreme flooding is identified under global warming. Previous studies that have neglected soil moisture dynamics are unlikely to give accurate flood estimates. Plain Language Summary: The future flood hazard status over the major UK urban region of Bristol (domain size ∼746 km2) is evaluated using the latest 12‐member UK Climate Projections Local ensemble rainfall data set at the hourly and kilometer scale. A total of 30,098 rainfall events from an equivalent 720 years of climate data are identified and used for flood modeling. Impact of changing precipitation pattern and soil moisture dynamics on surface water floods are evaluated, and the interaction between precipitation, inundation, infiltration, and soil wetness are handled simultaneously at a spatial resolution of ∼30 m or less using an improved hydrodynamic model (LISFLOOD‐FP). Our findings highlight a shift toward a later seasonal occurrence of extreme flooding under global warming. Specifically, a large proportion of future extreme flood hazards is projected to manifest in December, contrasting with historical trends where most extreme events occurred in November. Extreme precipitation can be magnified in rainy seasons due to amplified moisture convergence, while in dry periods limited moisture availability may offset precipitation increases. Despite an overall increase in the total annual rainfall volume, the future summer is anticipated to be much drier due to limited rainfall availability, leading to a further reduction in soil moisture availability. Key Points: Shifts to a later seasonal occurrence of extreme flooding is identified under global warming in the UKIncrease in annual total rainfall leads to a disproportionate rise in the resultant flood volumeImpact of the antecedent soil moisture on flood generation shows seasonality [ABSTRACT FROM AUTHOR]

This paper reviews the literature on corporate governance in extreme institutional environments, including both formal and informal institutions. We focus on three main areas of research: corporate governance in an international context, banking and corporate governance, and governance in entrepreneurship and innovation. We document some classic papers in each of these areas and explain how the papers in this special issue contribute to the development of these areas of research. We discuss recommendations for policy and practice and offer suggestions for future research. [ABSTRACT FROM AUTHOR]

Radio‐photovoltaic cell is a micro nuclear battery for devices operating in extreme environments, which converts the decay energy of a radioisotope into electric energy by using a phosphor and a photovoltaic converter. Many phosphors with high light yield and good environmental stability have been developed, but the performance of radio‐photovoltaic cells remains far behind expectations in terms of power density and power conversion efficiency, because of the poor photoelectric conversion efficiency of traditional photovoltaic converters under low‐light conditions. This paper reports an radio‐photovoltaic cell based on an intrinsically stable formamidinium‐cesium perovskite photovoltaic converter exhibiting a wide light wavelength response from 300 to 800 nm, high open‐circuit voltage (VOC), and remarkable efficiency at low‐light intensity. When a He ions accelerator is adopted as a mimicked α radioisotope source with an equivalent activity of 0.83 mCi cm−2, the formamidinium‐cesium perovskite radio‐photovoltaic cell achieves a VOC of 0.498 V, a short‐circuit current (JSC) of 423.94 nA cm−2, and a remarkable power conversion efficiency of 0.886%, which is 6.6 times that of the Si reference radio‐photovoltaic cell, as well as the highest among all radio‐photovoltaic cells reported so far. This work provides a theoretical basis for enhancing the performance of radio‐photovoltaic cells. [ABSTRACT FROM AUTHOR]

This paper discusses a method of determining the minimum safe altitude of an uncrewed aerial vehicle (UAV) at any point within a designated airspace by conducting a glide reachability analysis. Recently, fixed‐wing UAVs are more regularly deployed near population centers and in extreme environments, requiring increasingly robust emergency systems and planning. The long‐ranges and adverse terrain associated with monitoring the Volcán de Fuego in Guatemala by a team from the University of Bristol (UoB) increases the likelihood that motor failure would result in the aircraft being unable to Return To Home (RTH) and impossible to retrieve. A method for delineating a boundary representing the minimum safe altitude required for the aircraft to safely glide to the airfield in the event of a motor failure was developed within MATLAB, defined by the UAV's minimum glide angle in wind. This model was subsequently compared with flight data from UoB missions around Fuego to better improve its accuracy and analyze the limitations of the missions. [ABSTRACT FROM AUTHOR]

Aramid nanofibers (ANFs) exhibit desirable lightweight and excellent properties, while their strength has to be sacrificed to further improve their electrical insulation and fire resistance so as to meet the special demands of extreme environments. Herein, Zylon nanofibers (ZNFs) with analogous structure compatibility but superior performance are employed to construct an assembled dual‐network structure to improve the overall properties of ANFs. A facile in situ structure restoration (ISSR) strategy is proposed to achieve ZNF aqueous dispersion for the first time by deprotonation of ZNFs, which significantly avoids the corrosive acid system and facilitates the papermaking process. The composite ANF@ZNF nanopaper exhibits incredible tensile strength (233 MPa) and toughness (14.7 MJ m−3), increased by 108% and 584% compared with pure ANF nanopaper due to the dense entangled dual‐network and tremendous hydrogen bonds. Moreover, it presents superior breakdown strength of ≈128 kV mm−1, which is 6 times higher than that of commercial Nomex T410 insulation paper with a thickness of 50 µm. Besides, it exhibits surprising flame resistance (endure 1000 °C burning) ascribed to the excellent thermostability of ZNFs. This work provides promising possibilities for expanding the applications of aramid‐based composites for advanced electrical insulation and thermal protection in extremely harsh conditions. [ABSTRACT FROM AUTHOR]

This study presents a Monte‐Carlo simulation‐based approach to investigate how stochastic crane movements affect the structural reliability of the rail beam considering radiation effects. In the simulation, the rail beam loaded under a stochastically moving crane is discretized into 47 equispaced structural points for calculating its strain profile. Then the structural reliability at each structural point is calculated with the consideration of irradiation creep, represented as an accumulated strain over a given period of time. And the rail beam reliability is determined by the minimum value from the reliabilities calculated at different structural points, according to the weakest link principle. In our simulations, three candidate distributions, including the normal distribution, uniform distribution, and 3‐parameter lognormal distributions respectively, are applied to describe the stochastic distances of the crane. It can be seen from the simulation results that the rail beam reliability degrades with the most rapid rate when the crane distances follow a normal distribution, compared to the other two distributions. This paper offers a possible way of using the proposed Monte‐Carlo simulation‐based method to carry out reliability analysis and improvements for the rail beam working in extreme environments, such as irradiation conditions, with random operational tasks. [ABSTRACT FROM AUTHOR]

The author discusses investigations into potential economic implications of space weather events and the issuance of Executive Order (EO) "Coordinating Efforts to Prepare the Nation for Space Weather Events," by outgoing U.S. President Barack Obama in October 2016. Topics discussed include the way space weather events may affect operations of electricity grids, the implementation of the EO by presidential candidate Donald Trump, and the need to reduce risks associated with space weather events.

This paper follows a historical background on requirements‐based strategic armor research, leading to the materials in extreme dynamic environments program presented in Part I, now focusing on the developed technical aspects and state‐of‐the‐art. It starts with some background on dynamic testing techniques and a structural ceramics review. Then, selected armor ceramics research results and relevant single‐grain anisotropic crystal physics, microstructure, and defect mechanics mechanisms: Including pivotal armor ceramics research results prior to the adoption of the strategic research objective (SRO). Next, multiscale characteristics, crystal physics, planar features, anisotropy, and relevant mechanisms will be described. The historic progression/evolution of multiscale lightweight armor ceramics research results will be summarized, including multiscale dynamic deformation and damage characteristics. The focus of the following sections will be on the role of defects, quasi‐plasticity, and anisotropic crystal physics properties, including preexisting single grain synthesis and process‐induced planar features (aka twins) and planar deformation features (PDF); for example, nano‐amorphization in boron carbide. A new model for boron carbide processing planar features will be discussed. A schematic diagram illustrating the hypothetical formation of PDFs in a dynamic event is also presented. An expended canonical equation is introduced, suggesting possible strategies for boron carbide research using the canonical figures of merit approach. Finally, we highlight the efficacy of the materials by design process and approach in a multiscale framework for the simultaneous experimental and theoretical research trajectories guided by the accepted canonical equation. [ABSTRACT FROM AUTHOR]

Nowadays, phosphors are widely used in high quality white light emitting diodes (W‐LEDs) and display technology. Micro light emitting diode (Micro‐LED) has the advantages of ultrahigh resolution color saturation, while ordinary phosphors are difficult to apply due to their large particle size. As is known to all, once the phosphor particle size is reduced, its luminescence intensity will loser. This paper presents a strategy to improve the luminescence intensity of sub‐micrometer narrow‐band red phosphors. By increasing the doping concentration of rare‐earth ions through total substitution and reducing the nonradiative transition in the cell, ultrahigh concentration doping of sub‐micrometer phosphors is achieved to improve the luminescence intensity. Surprisingly, with increasing Eu3+ up to entirely substitution for Gd3+ site, both the absorption efficiency and the internal quantum efficiency of the sample increased greatly. The external quantum efficiency increased from 5.42% to 19.70%. Sub‐micrometer EuAl3(BO3)4 exhibits ultrahigh thermal stability, with a luminous intensity at 225 °C that is 128% of that at room temperature, meeting the conditions of extreme high‐temperature environments or high‐power LEDs. In summary, this work has great potential for application in W‐LED and presents a solution idea to solve the luminous intensity reduction of sub‐micrometer phosphors. [ABSTRACT FROM AUTHOR]

The opening of the Hålogaland Bridge December 2018 marked a milestone for modern suspension bridge design. It is an example of how technical knowhow is innovating the design of suspension bridges, in particular cable structure design. This paper will explain the overall design of the bridge with specific focus on the cable structure design including the main cables, anchorages, saddles and cable clamps. Furthermore, the construction of the bridge will be briefly mentioned focusing on the challenges of constructing such a major landmark structure in the extreme environment more than 300km north of the Arctic Circle. [ABSTRACT FROM AUTHOR]

With Cyber warfare, detection of hardware Trojans, malicious digital circuit components that can leak data and degrade performance, is an urgent issue. Quasi‐Delay Insensitive asynchronous digital circuits, such as NULL Convention Logic (NCL) and Sleep Convention Logic, also known as Multi‐Threshold NULL Convention Logic (MTNCL), have inherent security properties and resilience to large fluctuations in temperatures, which make them very alluring to extreme environment applications, such as space exploration, automotive, power industry etc. This paper shows how dual‐rail encoding used in NCL and MTNCL can be exploited to design Trojans, which would not be detected using existing methods. Generic threat models for Trojans are given. Formal verification methods that are capable of accurate detection of Trojans at the Register‐Transfer‐Level are also provided. The detection methods were tested by embedding Trojans in NCL and MTNCL Rivest‐Shamir‐Adleman (RSA) decryption circuits. The methods were applied to 25 NCL and 25 MTNCL RSA benchmarks of various data path width and provided 100% rate of detection. [ABSTRACT FROM AUTHOR]

Bond coats in environmental barrier coatings (EBCs) prevent oxidants from penetrating the substrate, mediate the mismatch of the coefficient of thermal expansion (CTE), and improve the adhesion strength between adjacent layers. However, the development of bond coats is rarely studied systematically. In this paper, the research status of the bond coats in EBCs is introduced in detail, including the materials and deposition methods. Thus far, Si, modified‐Si, mullite, etc., have been employed as bond coats. Nevertheless, visible drawbacks of each bond coat limit their application at high‐temperatures in extreme environments. Si bond coat is easily oxidized and forms thermally grown oxides that form cracks, resulting in delamination, spallation, and failure of EBCs. In the Si–HfO2 bond coat, the optimal ratios of Si/HfO2, deposition methods, distribution of Si and HfO2, and oxidation of Si remain completely unsolved. For mullite bond coat, SiO2 suffers selective evaporation in the water vapor environment, and the ratios of the Al2O3 and SiO2 in mullite coatings restrict its service lifetime. HfSiO4 is a potential candidate acting as a next‐generation bond coat in EBCs is proposed. Furthermore, choosing reasonable deposition methods is beneficial to improve the performances of the bond coats in EBCs. [ABSTRACT FROM AUTHOR]

The Mars Science Laboratory (MSL) Curiosity rover landed in Gale crater in August of 2012 on its mission to explore Mt. Sharp as the first planetary rover to collect and analyze rock and regolith samples. On this new mission, sampling operations were conceived to be executed serially and in situ, on a "sample chain" along which sample would be collected, then processed, then delivered to sample analysis instruments, analyzed there, and then discarded so the chain could be repeated. This paper describes the evolution of this relatively simple chain into a richer sampling network, responding to science and engineering desires that came into focus only as the mission matured, scientific discoveries were made, and anomalies were encountered. The rover flight and ground system architectures retained significant heritage from past missions, while extending capabilities in anticipation of the need for adaptation. As evolution occurred, the architecture permitted nimble extension of sampling behavior without time‐consuming flight software updates or significant impact to daily operations. This paper presents the major components of this architecture and discusses some of the results of successful adaptation across thousands of Sols of Mars operations. [ABSTRACT FROM AUTHOR]

The recent increase in extreme climatic phenomena has gradually attracted the attention of researchers regarding urban flooding. This paper used a hydrological model combined with the Computational Fluid Dynamics software to assess the drainage efficiency, predict the hydrological processes under different precipitation intensities and establish the relationship between rainfall intensity and inundation depth under extreme rainstorm events. The study proposed several thresholds such as specific rainfall intensities (that is, RI95% and RI50%), drainage efficiency, and the limited flow rate of pipes. Based on 2021 July 20, 0:00 to 24:00 precipitation monitoring data from the "7.20 Zhengzhou Rainstorm Extreme Event," the relationship between rainfall intensity and road‐pipe overflow patterns was determined by analysing these thresholds for different drainpipe diameters and spacings of catchment wells. The results demonstrated the evaluation parameters varied with rainfall intensities and pipe characteristics and revealed the main limitation of drainage efficiency and flow rate of drainpipes. The simulation helped the drainage systems design for different precipitations and proposed several relative suggestions for drainage‐system improvements, wherein the diameter of the branch pipes plays a dominant role in coping with extreme rainstorm events. [ABSTRACT FROM AUTHOR]

Probiotic is a functional food ingredient that is commonly used in the manufacturing of fermented dairy products and vegetable‐based foods. The consumption of probiotics has been claimed to confer health benefits to the host. However, probiotic cells are sensitive to harsh environments such as extreme pH and enzymes in the gastrointestinal tract. Hence, the microencapsulation technique is often adopted to shield probiotics from the outer environment. This review introduces a more advanced extrusion technique called co‐extrusion, which has been used to microencapsulate probiotics over the last few years. Both co‐extrusion technique and extrusion technique in microencapsulating probiotics were discussed extensively in this article. Furthermore, the impact of encapsulating probiotics in contrast with unencapsulated cells was also presented. This review highlighted some of the factors that might cause low viable cell count during microencapsulation and large microbead size. Lastly, the survivability of encapsulated probiotics in gastrointestinal digestion and storage under different temperatures were evaluated and the importance of probiotic microencapsulation was also emphasized. Practical Applications: The detailed information on extrusion and co‐extrusion techniques for probiotics microencapsulation is presented in this review. This information is useful for researchers and industrialists in understanding and applying both encapsulation techniques on probiotics for different purposes. Through this paper, the readers would also gain more insight into the factors affecting the viability and microbead size of the encapsulated probiotic to further optimize the extrusion and co‐extrusion encapsulation process. Furthermore, the ideal storage temperature and additional drying process for the encapsulated probiotic identified in this review would open opportunities for industrialists to produce functional probiotic products with a high viable cell count. [ABSTRACT FROM AUTHOR]

The estimation of sea levels corresponding to high return periods is crucial for coastal planning and for the design of coastal defenses. This paper deals with the use of historical observations, that is, events that occurred before the beginning of the systematic tide gauge recordings, to improve the estimation of design sea levels. Most of the recent publications dealing with statistical analyses applied to sea levels suggest that astronomical high tide levels and skew surges should be analyzed and modeled separately. Historical samples generally consist of observed record sea levels. Some extreme historical skew surges can easily remain unnoticed if they occur at low or moderate astronomical high tides and do not generate extreme sea levels. The exhaustiveness of historical skew surge series, which is an essential criterion for an unbiased statistical inference, can therefore not be guaranteed. This study proposes a model combining, in a single Bayesian inference procedure, information of two different natures for the calibration of the statistical distribution of skew surges: measured skew surges for the systematic period and extreme sea levels for the historical period. A data‐based comparison of the proposed model with previously published approaches is presented based on a large number of Monte Carlo simulations. The proposed model is applied to four locations on the French Atlantic and Channel coasts. Results indicate that the proposed model is more reliable and accurate than previously proposed methods that aim at the integration of historical records in coastal sea level or surge statistical analyses. Plain Language Summary: Coastal facilities must be designed as to be protected from extreme sea levels. Sea levels at high tide are the combination of astronomical high tides, which can be predicted, and skew surges. The estimation of the statistical distribution of skew surges is usually based on the skew surges measured by tide gauges and can be improved with the use of historical information, observations that occurred before the beginning of the tide gauge recordings. Extreme skew surges combined with low or moderate astronomical high tides would not necessarily generate extreme sea levels, and consequently some extreme historical skew surges could be missed. The exhaustiveness of historical information is an essential criterion for an unbiased estimation, but it cannot be guaranteed in the case of historical skew surges. The present study proposes to combine skew surges for the recent period and extreme sea levels for the historical period. The proposed model is compared to previously published approaches and appears to be more reliable and accurate. The proposed model is applied to four case studies on the French Atlantic and Channel coasts. Key Points: The exhaustiveness of historical sea record information is demonstrated based on French Atlantic coast dataA comparative analysis of approaches to integrate historical information is carried outThe efficiency of a new method for the combination of systematic skew surges and historical records is verified [ABSTRACT FROM AUTHOR]

Summary: Plant Ecophysiology is the study on how Plant Physiology is modulated by the environment. This discipline could have benefited greatly from the development of the different 'omic' technologies (from genomics to metabolomics). Instead, the overall impression is that ecophysiology and 'omics' have developed mostly independent each other. Here we provide a literature analysis over the past 20 years which fully confirms this view. Then, we review a few examples of studies in which ecophysiology and 'omics' studies have combined to different extents to illustrate the potential benefits from their mutualistic interaction. In addition, we debate on the possibilities of working with plants other than Arabidopsis, which is illustrated with some examples of fascinating plants from extreme environments of the world, what we call the 'sherplants'. Finally, we raise a call to both communities (ecophysiology and 'omics') to integrate these disciplines to enter an 'ecophysiolomics era' to maximize our understanding about plant mechanisms from a multidisciplinary approach. Significance Statement: In this work we analyzed the relationship between the 'omic' technologies and plant ecophysiology. Literature data show that they developed mostly independent each other over the last 20 years. This fact promotes separated communities in each field losing the potential benefits from their mutualistic interaction. Here, we raise a call to both communities to integrate these disciplines to maximize our understanding about plant mechanisms from a multidisciplinary approach. [ABSTRACT FROM AUTHOR]

In order to truly understand the physics of environmental flow, one must understand the mixing and transport process. A better understanding of mixing and transport phenomena will in turn be crucial to predict the fate and transport of contaminants in environmental flows. The present review is intended to constitute and discuss the key points of the mixing and transport papers published in 2007. Many papers reviewed herein are grouped into general mixing and fluid dynamics, some active areas related to environmental fate and transport, riverine, lacustrine, estuarine and coastal systems and then into subfields within these categories. [ABSTRACT FROM AUTHOR]

Legged robots are exceedingly versatile and have the potential to navigate complex, confined spaces due to their many degrees of freedom. As a result of the computational complexity, there exist no online planners for perceptive whole‐body locomotion of robots in tight spaces. In this paper, we present a new method for perceptive planning for multilegged robots, which generates body poses, footholds, and swing trajectories for collision avoidance. Measurements from an onboard depth camera are used to create a three‐dimensional map of the terrain around the robot. We randomly sample body poses then smooth the resulting trajectory while satisfying several constraints, such as robot kinematics and collision avoidance. Footholds and swing trajectories are computed based on the terrain, and the robot body pose is optimized to ensure stable locomotion while not colliding with the environment. Our method is designed to run online on a real robot and generate trajectories several meters long. We first tested our algorithm in several simulations with varied confined spaces using the quadrupedal robot ANYmal. We also simulated experiments with the hexapod robot Weaver to demonstrate applicability to different legged robot configurations. Then, we demonstrated our whole‐body planner in several online experiments both indoors and in realistic scenarios at an emergency rescue training facility. ANYmal, which has a nominal standing height of 80 cm and a width of 59 cm, navigated through several representative disaster areas with openings as small as 60 cm. Three‐meter trajectories were replanned with 500 ms update times. [ABSTRACT FROM AUTHOR]

Deploying robots to explore venues that are inaccessible to humans, or simply inhospitable, has been a longstanding ambition of scientists, engineers, and explorers across numerous fields. The deep sea exemplifies an environment that is largely uncharted and denies human presence. Central to exploration is the capacity to deliver dexterous robotic manipulation to this unstructured environment. Unmanned underwater vehicles (UUVs) are successful in providing passive solutions for observation and mapping but currently are far from capable of delivering human‐level dexterity. The ones providing manipulation typically are UUVs coupled with position‐controlled hydraulic arms using disjoint controllers for navigation and manipulation that require expert operators. Ocean One is a humanoid underwater robot designed specifically for underwater manipulation. In this paper, we present Ocean One's control architecture that, through a collaboration between this humanoid robot and a human pilot, enables the deployment of dexterous robotic manipulation to the deep sea. We provide detailed descriptions of this architecture's two main components: first, a whole‐body controller that creates functional autonomy by coordinating manipulation, posture, and constraint tasks, and second, a set of haptic and visual human interfaces that enable intimate interaction while avoiding micromanagement. We test the presented methods in simulation and validate them in pool experiments and in two field deployments. On its maiden mission into the Mediterranean Sea, Ocean One explored the Lune, a French naval vessel that sank in 1664 off the coast of Toulon, France. In its second expedition, Ocean One assisted human divers in investigating underwater volcanic structures at Santorini, Greece. [ABSTRACT FROM AUTHOR]

Robotic technologies, whether they are remotely operated vehicles, autonomous agents, assistive devices, or novel control interfaces, offer many promising capabilities for deployment in real‐world environments. Postdisaster scenarios are a particularly relevant target for applying such technologies, due to the challenging conditions faced by rescue workers and the possibility to increase their efficacy while decreasing the risks they face. However, field‐deployable technologies for rescue work have requirements for robustness, speed, versatility, and ease of use that may not be matched by the state of the art in robotics research. This paper aims to survey the current state of the art in ground and aerial robots, marine and amphibious systems, and human–robot control interfaces and assess the readiness of these technologies with respect to the needs of first responders and disaster recovery efforts. We have gathered expert opinions from emergency response stakeholders and researchers who conduct field deployments with them to understand these needs, and we present this assessment as a way to guide future research toward technologies that will make an impact in real‐world disaster response and recovery. [ABSTRACT FROM AUTHOR]

The work reported in this article describes the research advances and the lessons learned by the Robotics, Perception and Real‐Time group over a decade of research in the field of ground robotics in confined environments. This study has primarily focused on localization, navigation, and communications in tunnel‐like environments. As will be discussed, this type of environment presents several special characteristics that often make well‐established techniques fail. The aim is to share, in an open way, the experience, errors, and successes of this group with the robotics community so that those that work in such environments can avoid (some of) the errors made. At the very least, these findings can be readily taken into account when designing a solution, without needing to sift through the technical details found in the papers cited within this text. [ABSTRACT FROM AUTHOR]

Icebergs pose many challenges to offshore operations in the Arctic Ocean and sub‐arctic regions. They could damage underwater infrastructure such as pipelines, and disrupt marine transportation. The below‐water shape of an iceberg is a key factor for iceberg management in the North Atlantic Ocean because it affects the iceberg towing plans and iceberg drift patterns. In recent years, unmanned platforms have been proposed as potential candidates for underwater iceberg mapping. Compared to a conventional ship‐based iceberg survey, using unmanned platforms is more efficient and safer. In this paper, we present research using a hybrid underwater glider to measure the underwater shape of an iceberg. The vehicle is equipped with a mechanical scanning sonar for range sensing and iceberg mapping, and a guidance system is designed to use the sonar measurements for guiding the vehicle to circumnavigate an iceberg at the desired standoff distance. Several field experiments have been conducted on an iceberg to evaluate the system performance. With repeated observations, the underside of the target iceberg was successfully reconstructed, and iceberg shape comparisons are presented. [ABSTRACT FROM AUTHOR]

Mobile robots outfitted with a supportive tether are ideal for gaining access to extreme environments for mapping when human or remote observation is not possible. This paper is a field report covering both the development and field testing of our Tethered Robotic eXplorer (TReX) to map a steep, tree‐covered rock outcrop in a gravel mine. TReX is a mobile robot designed for the purpose of mapping extremely steep and cluttered environments for geologic and infrastructure inspection. In comparison to other systems, our design improves tethered mobility by enabling rotational freedom on steep slopes using a center‐pivoting tether management payload. To map the terrain, we leverage the rotation of an actuated tether spool with an attached two‐dimensional (2D) lidar, which rotates to both manage tether and produce 3D scans. Given that mapping requires vehicle motion, we also evaluate two existing, real‐time approaches to estimate the trajectory of the robot and rectify motion distortion from individual scans before alignment into the map: (a) a continuous‐time, lidar‐only approach that handles asynchronous measurements using a physically motivated, constant‐velocity motion prior, and (b) a method that computes visual odometry from streaming stereo images to use as a motion estimate during scan collection. Once rectified, individual scans are matched to the global map by an efficient variant of the Iterative Closest Point (ICP) algorithm. Our results include a comparison of estimated maps and trajectories to ground truth (measured by a remote survey station), an example of mapping in highly cluttered terrain, and lessons learned from the design and deployment of TReX. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a real‐time and channel‐invariant visibility enhancement algorithm using a hybrid image enhancement approach. The proposed method is initially motivated by an underwater visual simultaneous localization and mapping (SLAM) failure in a turbid medium. The environments studied contain various particles and are dominated by a different image degradation model. Targeting image enhancement for degraded images but not being limited to it, the proposed method provides a highly effective solution for both color and gray images with substantial improvement in the process time compared to conventional methods. The proposed method introduces a hybrid scheme of two image enhancement modules: a model‐based (extensive) enhancement and a model‐free (immediate) enhancement. The proposed method is validated by using simulated synthetic color images and real‐world color and grayscale underwater images. Real‐world validation is performed in various environments such as hazy indoor, smoky indoor, and underwater. Using the ground truth trajectory or clear images acquired from the same area but without turbidity, we evaluate the proposed visibility enhancement and camera registration improvement for a feature based (ORB‐SLAM2), a direct (LSD‐SLAM), and a visual underwater SLAM application. [ABSTRACT FROM AUTHOR]

Abstract: Legged robots are an efficient alternative for navigation in challenging terrain. In this paper we describe Weaver, a six‐legged robot that is designed to perform autonomous navigation in unstructured terrain. It uses stereo vision and proprioceptive sensing based terrain perception for adaptive control while using visual‐inertial odometry for autonomous waypoint‐based navigation. Terrain perception generates a minimal representation of the traversed environment in terms of roughness and step height. This reduces the complexity of the terrain model significantly, enabling the robot to feed back information about the environment into its controller. Furthermore, we combine exteroceptive and proprioceptive sensing to enhance the terrain perception capabilities, especially in situations in which the stereo camera is not able to generate an accurate representation of the environment. The adaptation approach described also exploits the unique properties of legged robots by adapting the virtual stiffness, stride frequency, and stride height. Weaver's unique leg design with five joints per leg improves locomotion on high gradient slopes, and this novel configuration is further analyzed. Using these approaches, we present an experimental evaluation of this fully self‐contained hexapod performing autonomous navigation on a multiterrain testbed and in outdoor terrain. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a teach‐and‐repeat path‐following method for an autonomous underwater vehicle (AUV) navigating long distances in environments where external navigation aides are denied. This method utilizes sonar images to construct a series of reference views along a path, stored as a topological map. The AUV can then renavigate along this path, either to return to the start location or to repeat the route. Utilizing unique assumptions about the sonar image‐generation process, this system exhibits robust image‐matching capabilities, providing observations to a discrete Bayesian filter that maintains an estimate of progress along the path. Image‐matching also provides an estimate of offset from the path, allowing the AUV to correct its heading and effectively close the gap. Over a series of field trials, this system demonstrated online control of an AUV in the ocean environment of Holyrood Arm, Newfoundland and Labrador, Canada. The system was implemented on an International Submarine Engineering Ltd. Explorer AUV and performed multiple path completions over both a 1 and 5 km track. These trials illustrated an AUV operating in a fully autonomous mode, in which navigation was driven solely by sensor feedback and adaptive control. Path‐following performance was as desired, with the AUV maintaining close offset to the path. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we propose a LiDAR‐based robot localization method in a complex oil and gas environment. Localization is achieved in six degrees of freedom (DoF) thanks to a particle filter framework. A new time‐efficient likelihood function, based on a precalculated three‐dimensional likelihood field, is introduced. Experiments are carried out in real environments and their digitized point clouds. Six DoF real‐time localization is achieved with spatial and angular errors of less than 2.5 cm and 1°,  respectively, in a real environment of 350 m 3. The proposed approach focuses on real‐time performance on embedded platforms. It enabled the Vikings team to win the first two ARGOS Challenge contests. [ABSTRACT FROM AUTHOR]

Microbial communities from extreme environments are largely understudied, but are essential as producers of metabolites, including enzymes, for industrial processes. As cultivation of most microorganisms remains a challenge, culture‐independent approaches for enzyme discovery in the form of metagenomics to analyse the genetic potential of a community are rapidly becoming the way forward. This study focused on analysing a metagenome from the cold and alkaline ikaite columns in Greenland, identifying 282 open reading frames (ORFs) that encoded putative carbohydrate‐modifying enzymes with potential applications in, for example detergents and other processes where activity at low temperature and high pH is desired. Seventeen selected ORFs, representing eight enzyme families were synthesized and expressed in two host organisms, Escherichia coli and Aliivibrio wodanis. Aliivibrio wodanis demonstrated expression of a more diverse range of enzyme classes compared to E. coli, emphasizing the importance of alternative expression systems for enzymes from extremophilic microorganisms. To demonstrate the validity of the screening strategy, we chose a recombinantly expressed cellulolytic enzyme from the metagenome for further characterization. The enzyme, Cel240, exhibited close to 40% of its relative activity at low temperatures (4°C) and demonstrated endoglucanase characteristics, with a preference for cellulose substrates. Despite low sequence similarity with known enzymes, computational analysis and structural modelling confirmed its cellulase‐family affiliation. Cel240 displayed activity at low temperatures and good stability at 25°C, activity at alkaline pH and increased activity in the presence of CaCl2, making it a promising candidate for detergent and washing industry applications. [ABSTRACT FROM AUTHOR]

A large stretch of the east coast of Australia experienced unprecedented rainfall and flooding over a two‐week period in early 2022. It is difficult to reliably estimate the likelihood of such a rare event from the relatively short observational record, so an alternative is to use data from an ensemble prediction system (e.g., a seasonal or decadal forecast system) to obtain a much larger sample of simulated weather events. This so‐called 'UNSEEN' method has been successfully applied in several scientific studies, but those studies typically rely on a single prediction system. In this study, we use data from the Decadal Climate Prediction Project to explore the model uncertainty associated with the UNSEEN method by assessing 10 different hindcast ensembles. Using the 15‐day rainfall total averaged over the river catchments impacted by the 2022 east coast event, we find that the models produce a wide range of likelihood estimates. Even after excluding a number of models that fail basic fidelity tests, estimates of the event return period ranged from 320 to 1814 years. The vast majority of models suggested the event is rarer than a standard extreme value assessment of the observational record (297 years). Such large model uncertainty suggests that multi‐model analysis should become part of the standard UNSEEN procedure. [ABSTRACT FROM AUTHOR]

The concept of ‘best management practice’ (BMP) has become popular in the context of natural resource management in Australia and is a core principle of the National Action Plan for Salinity and Water Quality. However, despite the emergence of this concept, it seems to have been mostly overlooked for critical assessment by geographers and social scientists. This paper presents an overview of the BMP concept and its use in natural resource management, identifying two distinct types of BMP, one associated with regulation and one focused on innovation. The paper presents findings from focus groups with farmers and scientists seeking to implement BMP to manage dryland salinity in the Western Australian wheatbelt. The focus of the paper concerns defining what is meant by BMP for managing dryland salinity, and drawing attention to complications with the BMP concept as it is used in Australia to address salinity. In particular, the paper discusses the contested nature of defining BMP against a background of imperfect knowledge. As a complex environmental problem, a prescriptive approach to BMP for the management of dryland salinity is problematic. However, the concept has some merit when conceptualised as a process of continual improvement and learning. [ABSTRACT FROM AUTHOR]

This paper introduces an autonomous system employing multirotor unmanned aerial vehicles for fast 3D exploration and inspection of vast, unknown, dynamic, and complex environments containing large open spaces as well as narrow passages. The system exploits the advantage of small‐size aerial vehicles capable of carrying all necessary sensors and computational power while providing full autonomy and mobility in constrained unknown environments. Particular emphasis is put on the robustness of the algorithms with respect to challenging real‐world conditions and the real‐time performance of all algorithms that enable fast reactions to changes in environment and thus also provide effective use of limited flight time. The system presented here was employed as a part of a heterogeneous ground and aerial system in the modeled Search & Rescue scenario in an unfinished nuclear power plant during the Urban Circuit of the Subterranean Challenge (SubT Challenge) organized by the Defense Advanced Research Projects Agency. The main goal of this simulated disastrous scenario is to autonomously explore and precisely localize specified objects in a completely unknown environment and to report their position before the end of the mission. The proposed system was part of the multirobot team that finished in third place overall and in first place among the self‐funded teams. The proposed unmanned aerial vehicle system outperformed all aerial systems participating in the SubT Challenge with respect to versatility, and it was also the self‐deployable autonomous aerial system that explored the largest part of the environment. [ABSTRACT FROM AUTHOR]

The immediate local impacts of the eruption of Mount Tambora, Sumbawa, Indonesia in April 1815 were devastating, resulting in the loss of an estimated 60 000 lives on this and neighbouring islands. However, the longer term effects of the largest known historical eruption on global weather and climate and the related consequences for human health and wellbeing have maintained the prominence of the eruption in public memory. Among the most notable effects were global weather anomalies the following year, which has come to be referred to as 'the year without summer'. Scholars across the sciences and humanities continue to investigate the eruption, seeking insights into the likely meteorological and societal impacts of future volcanic eruptions. The bicentenary of the 'year without summer' in 2016 provides a timely moment to revisit this weather episode. In this paper, we draw on a range of archival materials and contemporary publications to reconstruct the weather year and explore how the summer of 1816 was experienced and recorded across the UK. We also wish to demonstrate the importance of historical contingency in understanding the potential implications of the event at the local level, and of situating events within their appropriate temporal context. We do this by considering the summer of 1816 as set against the wider weather and cultural contexts of the 1810s. Our findings illustrate that in a UK context, summer 1816 was characterised by unusual and extreme weather events. Importantly it also took place within a sequence of years that were similarly replete with anomalous and challenging weather conditions. [ABSTRACT FROM AUTHOR]

ABSTRACT It is known that the El Niño - Southern Oscillation ( ENSO) episodes have a great influence on South American precipitation and its extreme events during austral autumn (from March until May, MAM) and winter (from June until August, JJA) that occur after the ENSO peak (normally this happens on austral summer). Recent papers have studied the two types of ENSO and their influence on atmosphere-ocean system. This study analysed the influence of Central and East equatorial Pacific ENSO on South American seasonal/monthly mean precipitation and its extreme events during MAM and JJA. The composites of precipitation anomalies, during these two types of ENSO, show that there are different, even opposite patterns over South America. In MAM, there is an increased precipitation in southeastern South America and a decrease in the northeast South America during East El Niño ( EEN) and an increased precipitation in central Brazil during Central El Niño ( CEN). In JJA, the signs of anomaly precipitation are opposite between CEN (less precipitation) and EEN (more precipitation) over southeastern South America. The extreme precipitation events show patterns consistent with the precipitation anomaly patterns, but, normally, the changes in the frequency of extremes precipitation events affect more extensive areas than the total precipitation. If monthly or seasonal atmospheric anomalies in a certain region during one of the types of ENSO are similar (opposite) to the atmospheric anomalies associated with extreme precipitation events in this region, then there is enhancement (suppression) of the frequency of extreme events in this region during this type of ENSO. [ABSTRACT FROM AUTHOR]

Surface wetting prevents surface fogging on transparent materials by facilitating filmwise condensation with specific chemistry, but suffers from material and geometry selectivity. Extreme environments associated with high humidity and mechanical loading further limit their anti‐fogging persistence. Here, a stretchable anti‐fogging tape (SAT) that can be applied to diverse transparent materials with varied curvatures for persistent fogging prevention is reported. The SAT consists of three synergistically combined transparent layers: i) a stretchable and tough layer with large elastic recovery, ii) an endurant anti‐fogging layer insensitive to ambient humidity, and iii) a robustly and reversibly adhesive layer. The SAT maintains high total transmittance (>90%) and low diffuse transmittance (<5%) in high‐humidity environments, under various modes of mechanical deformations, and over a prolonged lifetime (193 days tested so far). Two applications are demonstrated, including the SAT‐adhered eyeglasses and goggles for clear fog‐free vision, and the SAT‐adhered condensation cover for efficient solar‐powered freshwater production. [ABSTRACT FROM AUTHOR]

The crustal evolution of the southernmost ∼2000–1800 Ma Trans‐Hudson orogen (THO) is enigmatic due to burial by Phanerozoic sediments. We provide new insights through petrochronologic analysis of a paragneiss drill core sample. Detrital zircon age peaks at 2625, 2340, and 1880 Ma and Hf isotopes suggest Paleoproterozoic arc development proximal to Archean source(s). Phase equilibria modeling and ternary feldspar thermometry suggest peak conditions of ≥1 GPa, ≥900°C, the first recognition of extreme, ultra‐high temperature metamorphism in the THO. The largely isobaric P‐T path, rapid heating rate, and ∼20 Myr duration (1872–1850 Ma) of peak conditions suggest that this metamorphism occurred in a back‐arc tectonic setting. The sample records post‐peak (1850–1815 Ma) mid‐crustal residence, slow cooling, and exhumation. Further retrogression occurred during Proterozoic regional exhumation (1630–1470 Ma) and Phanerozoic (360–220 Ma) reheating and/or fluid influx. Evidence for Paleoproterozoic arc(s) supports geophysical data for Archean cratonic and Paleoproterozoic arc crust in this region. Plain Language Summary: The Trans‐Hudson orogeny was a Himalayan‐scale collisional mountain building event approximately 1.8 billion years ago that formed the core of North America. The southern portion of the Trans‐Hudson orogen (THO) is poorly understood because it is almost entirely buried by younger rocks. It is unknown whether the southern THO is underlain by Archean or Proterozoic crust. The timing, conditions, and setting of high‐grade metamorphism in this region are also poorly known. We carried out petrologic, geochemical, and geochronologic analyses on a metasedimentary rock sample recovered from drill core. Detrital zircon and tracer isotopic data show derivation from both Paleoproterozoic and Archean sources. This suggests that Paleoproterozoic magmatic arc(s) developed on or near Archean crust. The rock sample experienced extreme temperatures (≥900°C, ≥1 GPa) and partial melting between approximately 1870 and 1850 million years ago perhaps in a back‐arc tectonic setting. This marks the first recognition of extreme, ultra‐high temperature metamorphism in the THO. Later retrograde metamorphism occurred in the Mesoproterozoic and Phanerozoic. These constraints provide new understanding of the enigmatic southern THO and highlight the ability of a combined petrologic, geochemical, and geochronologic study to extract a comprehensive record of crustal evolution from a single sample. Key Points: Paleoproterozoic arc(s) buried beneath North Dakota developed proximal to, or on, Archean craton(s)Metamorphic temperatures of >900°C are the first recognition of ultra‐high temperature (UHT) metamorphism in the Trans‐Hudson orogenBack‐arc setting for UHT metamorphism indicated by isobaric P‐T path and short timescales of heating and peak conditions [ABSTRACT FROM AUTHOR]

Soft actuators have been an important research focus in robotics due to their advantages in nondestructive contact and excellent motion adaptability, which enable flexible manipulation, extreme environments exploration, and in vivo surgical treatment. Various soft robots actuated electrically, magnetically, optically, and fluidically are built toward different application scenarios. Among them, electrical actuation method is an advanced choice to actuate and control soft actuators that are expected to be compatible and integrated with existing industrial robotic systems and wearable intelligent devices. Current robotic systems have higher requirements on the actuators' function, which can be explored through material and structural designs. Based on a variety of deformable materials, the structural design enables the soft actuators to span from low dimension to high dimension with further improvement in function. Therefore, in this review, 2D and 3D electrical‐based soft actuators from the perspective of dimension design are introduced, which involve functional materials, structure design, and fabrication technology. Some novel 3D fabrication methods, such as the 3D compressive buckling process, are summarized to build 3D soft robots. This review aims at offering important guidelines for the development of soft actuators and the construction of integrated robotic systems in the future. [ABSTRACT FROM AUTHOR]

This paper investigates modeling of silicon-germanium heterojunction bipolar transistor noise parameters and impedance-matched Low-Noise Amplifiers (LNAs) intended for operation across a wide temperature range (from 93 to 393 K). In general, noise performance improves with cooling until about 150 K, then degrades some because of carrier freeze-out. With a temperature independent bias current, an LNA designed for 300 K operation shows acceptable performance from 93 to 393 K, albeit with some degradation of linearity below 120 K. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A versatile, compact heater designed at National Synchrotron Light Source‐II for in situ X‐ray nano‐imaging in a full‐field transmission X‐ray microscope is presented. Heater design for nano‐imaging is challenging, combining tight spatial constraints with stringent design requirements for the temperature range and stability. Finite‐element modeling and analytical calculations were used to determine the heater design parameters. Performance tests demonstrated reliable and stable performance, including maintaining the exterior casing close to room temperature while the heater is operating at above 1100°C, a homogenous heating zone and small temperature fluctuations. Two scientific experiments are presented to demonstrate the heater capabilities: (i) in situ 3D nano‐tomography including a study of metal dealloying in a liquid molten salt extreme environment, and (ii) a study of pore formation in icosahedral quasicrystals. The progression of structural changes in both studies were clearly resolved in 3D, showing that the new heater enables powerful capabilities to directly visualize and quantify 3D morphological evolution of materials under real conditions by X‐ray nano‐imaging at elevated temperature during synthesis, fabrication and operation processes. This heater design concept can be applied to other applications where a precise, compact heater design is required. [ABSTRACT FROM AUTHOR]

Antarctica poses numerous challenges to life such as cold shock, low nutrient concentrations, and periodic desiccation over a wide range of extreme temperatures. Cyanobacteria survive this harsh environment having evolved adaptive metabolic plasticity to become the dominant primary producers. The type strain cyanobacterium Halotia branconii CENA392 was isolated from an Antarctic intertidal seashore. The complete circular genome of this strain is presented herein, which was assembled using long‐sequence reads. The genome encoded some stress‐related genes associated with low‐temperature adaptation and biosynthesis of mycosporine‐like amino acid (MAA) photoprotective compounds. Empirical experimentation demonstrated constitutive production of the MAA porphyra‐334 and total carotenoids without exposure to low temperatures or ultraviolet radiation stress. Phylogenetic analysis provided insights on taxonomic placement and evolutionary history of some annotated genes. These data exemplify the importance of generating complete quality genome sequences of microorganisms isolated from extreme intertidal environments, facilitating in‐depth evaluation of ecological and taxonomic inferences. [ABSTRACT FROM AUTHOR]

The existence of time-dependent variance or conditional variance, commonly called heteroscedasticity, in hydrologic time series has not been thoroughly investigated. This paper deals with modelling the heteroscedasticity in the residuals of the seasonal autoregressive integrated moving average (SARIMA) model using a generalized autoregressive conditional heteroscedasticity (GARCH) model. The model is applied to two monthly rainfall time series from humid and arid regions. The effect of Box-Cox transformation and seasonal differencing on the remaining seasonal heteroscedasticity in the residuals of the SARIMA model is also investigated. It is shown that the seasonal heteroscedasticity in the residuals of the SARIMA model can be removed using Box-Cox transformation along with seasonal differencing for the humid region rainfall. On the other hand, transformation and seasonal differencing could not remove heteroscedasticity from the residuals of the SARIMA model fitted to rainfall data in the arid region. Therefore, the GARCH modelling approach is necessary to capture the heteroscedasticity remaining in the residuals of a SARIMA model. However, the evaluation criteria do not necessarily show that the GARCH model improves the performance of the SARIMA model. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper demonstrates the influence of low Rayleigh vibration on thermodiffusion measurement in microgravity environment. The goal is to show how the variation of certain parameters such as frequency and amplitude of translational vibrations would impact the results obtained from the ISS experiment. Precisely, impact of change in low Rayleigh vibration on the separation of a component is studied for each experimental run. ISS experimental data are obtained based on optical digital interferometry in a reduced gravity environment. The experiment is done in a cubic cell containing an aqueous solution exposed to a lateral temperature gradient. A mixture of water and isopropanol of different initial concentrations with positive and negative Soret coefficient is chosen as the test fluid. Collected data are analysed by image processing. Results show maximum separation of components for the case without any forced vibration. Moreover, an increase in Rayleigh number corresponds to decrease in the separation of components. [ABSTRACT FROM AUTHOR]

This paper aims to contribute to understanding the importance of four factors on the determination of sustainable yields: (i) aquifer properties; (ii) temporal distribution of recharge; (iii) temporal distribution of groundwater pumping; and (iv) spatial distribution of pumping wells. It is important to comprehend how the present-day and future vulnerability of groundwater systems to pumping activities depend on these critical factors and what the risks are of considering sustainable yield as a fixed percentage of mean annual recharge (MAR). A numerical model of the Querença-Silves aquifer in Portugal is used to develop hypothetical scenarios with which these factors are studied. Results demonstrate the aquifer properties, particularly the storage coefficient, have an important role in determining the resilience of an aquifer and therefore to which degree it is dependent on the spatial and temporal distribution of abstraction and recharge, as well as the occurrence of extreme events. Sustainable yields are determined for the developed scenarios based on specific criteria rather than a fraction of MAR. Under simplified current recharge and abstraction conditions, the sustainable yield was determined at approximately 73% of MAR or 76 million m3. When considering a concentration of rainfall in time, as predicted by climate scenarios for the region, sustainable yield could drop to ca 70% of MAR. However, a more even distribution of pumping volumes throughout the year could increase this value. The location of the pumping wells is seen to affect the distribution of hydraulic heads in the aquifer, albeit without significant changes in sustainable yield. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Climate change may significantly affect the hydrological cycle and water resource management, especially in arid and semi-arid regions. In this paper, output from the Providing Regional Climates for Impacts Studies (PRECIS) regional climate model were used in conjunction with the Soil and Water Assessment Tool (SWAT) to analyse the effects of climate change on streamflow of the Xiying and Zamu rivers in the Shiyang River basin, an important arid region in northwest China. After SWAT model calibration and validation, streamflow in the Shiyang River Basin was simulated using the PRECIS climate model data for greenhouse gas emission scenarios A2 (high emission rate) and B2 (low emission rate) developed by Intergovernmental Panel on Climate Change. Monthly streamflow and hydrological extremes were compared for present-day years (1961-1990), the 2020s (2011-2040), 2050s (2041-2070) and 2080s (2071-2100). The results show that mean monthly streamflow in Shiyang River Basin generally increased in the 2020s, 2050s and 2080s between 0.7-6.1% at the Zamu gauging station and 0.1-4.8% at the Xiying gauging station. The monthly minimum streamflow increased persistently, but the maximum monthly streamflows increased in the 2020s and slightly decreased in the 2050s and 2080s. This study provides valuable information for guiding future water resource management in the Shiyang River Basin and other arid and semi-arid regions in China. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper describes the design features and capabilities of a portable automated in-situ closed chamber (ISCC) for the quantification of CO2 fluxes in dryland soils where both photosynthetic and respiratory components may be associated with a cyanobacterial crust. The processes of CO2 flux in dryland soils are briefly described in order to clarify the conditions that make quantification of these fluxes problematic. The instrumentation currently available for in-situ soil CO2 flux measurements is then reviewed demonstrating their inadequacies for the dryland environment. The ISCC described here is a member of the closed or enrichment class of soil respiration chambers. The ISCC, however, features an optical window possessing high (>90%) transmission in the photosynthetic active region (PAR) of the solar irradiance spectrum, permitting observations of photosynthesis. The ISCC possesses automatic venting and purging so that gaseous concentrations inside the chamber do not change from ambient sufficiently to significantly affect diffusion. The ISCC features both active and passive cooling employing internal solid-state Peltier coolers and external aluminised Mylar respectively. This avoids severe disturbance of the microclimate within the chamber due to admission of high fluxes of PAR and permits in-situ operation under a wide range of ambient field temperatures (~ −5 to 40°C). Sensors internal to the chamber monitor temperature, relative humidity, irradiance and pressure. In this implementation the ISCC is coupled to a portable gas chromatograph (Agilent GC-3000) to sample the chamber atmosphere. Indicative data for Kalahari Sand soils of Botswana are presented as an illustration of the general performance characteristics. [ABSTRACT FROM AUTHOR]

Conflicts between intensive groundwater use and wetland conservation are widespread throughout arid and semiarid regions worldwide. These have become more significant wherever there has been a synchronism between pumping-based human development and the awakening of an environmental awareness in society. The Mancha Occidental aquifer provides an example of such an occurrence, which has given rise to noteworthy social conflicts. This paper presents a cross-policy analysis for wetland restoration measures, establishing the main reasons why funding-intensive agricultural, environmental, and water policies have only attained marginal success in recovering the area’s aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Aim To investigate the human impact on eastern Mediterranean ecosystems in a subhumid to semi-arid region of the Near East. Location This paper considers data from Bereket (1410–1440 m a.s.l.), an intramontane basin surrounded by the Kokayanık Tepe (1830 m a.s.l.) and the Beşparmak Dağları (2280 m a.s.l.), in the western Taurus Mountains of south-west Turkey. Methods Late Holocene samples were collected along an 800-cm-deep sediment profile cored in the secondary valley of the Bereket basin. Descriptive vegetation data and modern pollen samples (moss polsters) were collected at elevational intervals of c. 15 m along an altitudinal transect from the Bereket basin (over Tepe Düzen, 1600 m a.s.l.) to Ağlasun Dağı (1700 m a.s.l.). Information about the spatial distribution of the present land cover was obtained from ASTER satellite imagery. Digital elevation-derived data and geological information were used to examine the relationship between actual land cover and other environmental variables. Results The well dated Bereket sequence provides a unique record of biennial-to-decadal landscape changes driven primarily by intensive human impact from 360 cal. yrbc to 650 cal. yrad. Since 360 cal. yrbc, over-exploitation of the land has led to altitudinal variation of tree lines, a destruction of the natural forest ecosystems ( Pinus– Quercus cerris mixed forest), and an extensive spread of forest-steppe in the highlands. The present-day distribution of vegetation in the basin area shows that human activities remain the major factor influencing the character of modern ecosystems. Main conclusions This research demonstrates the long-term local destructive effects of human impacts on the mountainous ecosystems in a small Anatolian intramontane basin since 360 cal. yrbc, and the capacity of these ecosystems to recover during periods of reduced human impact. The late Holocene history and modern vegetation characteristics show that the past and present-day distribution and composition of vegetation are influenced primarily by human activity, and that substrate, elevation, slope and orientation are of secondary significance. [ABSTRACT FROM AUTHOR]

A prime aim of invasion biology is to predict which species will become invasive, but retrospective analyses have so far failed to develop robust generalizations. This is because many biological, environmental, and anthropogenic factors interact to determine the distribution of invasive species. However, in this paper we also argue that many analyses of invasiveness have been flawed by not considering several fundamental issues: (1) the range size of an invasive species depends on how much time it has had to spread (its residence time); (2) the range size and spread rate are mediated by the total extent of suitable (i.e. potentially invasible) habitat; and (3) the range size and spread rate depend on the frequency and intensity of introductions (propagule pressure), the position of founder populations in relation to the potential range, and the spatial distribution of the potential range. We explored these considerations using a large set of invasive alien plant species in South Africa for which accurate distribution data and other relevant information were available. Species introduced earlier and those with larger potential ranges had larger current range sizes, but we found no significant effect of the spatial distribution of potential ranges on current range sizes, and data on propagule pressure were largely unavailable. However, crucially, we showed that: (1) including residence time and potential range always significantly increases the explanatory power of the models; and (2) residence time and potential range can affect which factors emerge as significant determinants of invasiveness. Therefore, analyses not including potential range and residence time can come to misleading conclusions. When these factors were taken into account, we found that nitrogen-fixing plants and plants invading arid regions have spread faster than other species, but these results were phylogenetically constrained. We also show that, when analysed in the context of residence time and potential range, variation in range size among invasive species is implicitly due to variation in spread rates, and, that by explicitly assuming a particular model of spread, it is possible to estimate changes in the rates of plant invasions through time. We believe that invasion biology can develop generalizations that are useful for management, but only in the context of a suitable null model. [ABSTRACT FROM AUTHOR]