Matrix Configuration Research Articles

Diminished functional segregation and resilience are associated with symptomatic severity and cognitive impairments in schizophrenia: a large-scale study

BackgroundThe research findings on the topological properties of functional connectomes (TP-FCs) in patients with schizophrenia (SZPs) exhibit inconsistencies and contradictions, which can be attributed to limitations such as small sample...

Enhancing Flow Separation Control Using Hybrid Passive and Active Actuators in a Matrix Configuration

Efficient control of flow separation holds significant economic promise. This study investigates flow separation mitigation using an experimental platform featuring a combination of passive and active actuators arranged in a matrix configuration. The platform consists of 5 × 6 hybrid actuator units, each integrating a height-adjustable vortex generator and a micro-jet actuator. Inspired by the distributed pattern of V-shaped scales on shark skin, these actuator units are strategically deployed in a matrix configuration to reduce flow separation on a backward-facing ramp. Distributed pressure taps encircling the hybrid actuators monitor the flow state. Parametric analyses examine the effect of different control strategies. By adopting appropriate passive and active actuation patterns, effective pressure recovery on the ramp surface can be achieved. The most significant flow control outcome occurs when the actuators operate under combined active and passive excitation, harnessing the benefits of both control strategies. Particle image velocimetry (PIV) results confirm a notable reduction in flow separation under the best-controlled case. These findings suggest a promising future for flow control devices employing combined passive and active actuation in matrix-like configurations.

Influence of Nano-Fly Ash on mechanical properties, microstructure characteristics and sustainability analysis of Alkali Activated Concrete

Ordinary Portland Cement (OPC) composites significantly affect the atmosphere by emitting Carbon dioxide (CO2) during its production process. The addition of Nano Materials (NM) for the construction could change the matrix configuration at the nano level. Compared to other NMs, converting industrial by-products and locally available materials into nano size can enhance the characteristics of the binder composites. This research work focuses on the effects of Nano Fly ash (nFA), on the fresh, mechanical, microstructural, and thermal resistance properties of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) based Alkaline Activator Nano Concrete (AANC). The impact of adding nFA in various concentrations of 3 %, 6 %, 9 %, 12 %, and 15 % on the properties of AANC was studied. By adding nFA in an optimal proportion, the degree of geo-polymerization is improved which is found by Field Emission Scanning Electron Microscopy (FESEM), X-ray diffraction (XRD), Thermogravimetric analysis (TGA), Energy Dispersive X-Ray Analysis (EDAX) and Fourier Transform Infrared (FTIR). Results indicate that the addition of nFA significantly increased polymerization, reducing initial and final setting times by 13.3 %–52.5 % and 5.3 %–28.8 %, respectively. Moreover, nFA promoted the formation of polymer gel, leading to a denser microstructure with fewer cracks and refined pores, resulting in a substantial increase in mechanical strength, particularly with 9% nFA, achieving an optimal CS of 56.14 MPa after 28 days which is 37.97 % improvement compared to the mix without nFA. However, when nFA was added, beyond 9 %, the performances declined due to its high surface area resulting in a non-uniform dispersion that promoted agglomeration. This dispersion enhances the formation of C-A-S-H and C–S–H gels. The addition of nFA in AANC can be an environmentally friendly solution by reducing CO2 emissions, energy consumption, cost reduction and increased sustainability.

Interfacing Arduino Boards with Optical Sensor Arrays: Overview and Realization of an Accurate Solar Compass.

In this paper, an overview of the potentiality of Arduino boards is presented, together with a description of the Arduino interfacing with light multi-sensors. These sensors can be arranged in linear arrays or in a matrix configuration (CCD or CMOS type cameras) and are equipped with tens, hundreds, or even thousands of elements whose sizes range from a few microns to tens of microns. The use of these sensors requires electronics that have high time accuracy, since they work through regular pulses sent by an external source and, furthermore, have the ability to digitize and store voltage signals precisely and quickly. We show that, with the appropriate settings, a simple Arduino board can handle both 1D and 2D optical sensors. Finally, we describe a solar compass made with such a board coupled to one of the tested optical array sensors that is capable of providing the north direction with a very high degree of accuracy.

Fiber alignment in 3D collagen networks as a biophysical marker for cell contractility

Cells cultured in 3D fibrous biopolymer matrices exert traction forces on their environment that induce deformations and remodeling of the fiber network. By measuring these deformations, the traction forces can be reconstructed if the mechanical properties of the matrix and the force-free matrix configuration are known. These requirements limit the applicability of traction force reconstruction in practice. In this study, we test whether force-induced matrix remodeling can instead be used as a proxy for cellular traction forces. We measure the traction forces of hepatic stellate cells and different glioblastoma cell lines and quantify matrix remodeling by measuring the fiber orientation and fiber density around these cells. In agreement with simulated fiber networks, we demonstrate that changes in local fiber orientation and density are directly related to cell forces. By resolving Rho-kinase (ROCK) inhibitor-induced changes of traction forces, fiber alignment, and fiber density in hepatic stellate cells, we show that the method is suitable for drug screening assays. We conclude that differences in local fiber orientation and density, which are easily measurable, can be used as a qualitative proxy for changes in traction forces. The method is available as an open-source Python package with a graphical user interface.

Deep Reinforcement Learning and NOMA-Based Multi-Objective RIS-Assisted IS-UAV-TNs: Trajectory Optimization and Beamforming Design

In this paper, we discuss the co-optimized performance of multi-reconfigurable intelligent surface (RIS)-assisted integrated satellite-unmanned aerial vehicle-terrestrial network (IS-UAV-TN), where the multiple vehicle users are applied to the network under consideration. The performance optimization of IS-UAV-TNs faces two major challenges: one is the obstacles in the transmission path and the other is the highly dynamic communication environment caused by the UAV movement for the multiple ground vehicle users. To tackle these above issues efficiently, we will install RIS on the UAV for the purpose of reshaping the wireless transmission path. In addition, non-orthogonal multiple access (NOMA) protocols are considered as a new paradigm to address spectrum shortage and enhance connection quality. Considering the UAV energy consumption, the satellite transmission beamforming matrix and RIS phase shift configuration, a multi-objective optimization problem is proposed to maximize the system achievable rate and minimize the UAV energy consumption during a specific mission. On this foundation, to facilitate the online decision problem, the deep reinforcement learning (DRL) algorithm is utilized to achieve real-time interaction with the communication environment. A multi-objective deep deterministic policy gradient (MO-DDPG) algorithm is proposed to search for sub-optimal solutions about the learning problem of multi-objective control policies in IS-UAV-TNs. Experimental results show that the method can simultaneously consider three optimization objectives and effectively adjust the optimal update policy according to the settings of different weight parameters.

Spatial–temporal features-based EEG emotion recognition using graph convolution network and long short-term memory

Objective. Emotion recognition on the basis of electroencephalography (EEG) signals has received a significant amount of attention in the areas of cognitive science and human–computer interaction (HCI). However, most existing studies either focus on one-dimensional EEG data, ignoring the relationship between channels, or only extract time–frequency features while not involving spatial features. Approach. We develop spatial–temporal features-based EEG emotion recognition using a graph convolution network (GCN) and long short-term memory (LSTM), named ERGL. First, the one-dimensional EEG vector is converted into a two-dimensional mesh matrix, so that the matrix configuration corresponds to the distribution of brain regions at EEG electrode locations, thus to represent the spatial correlation between multiple adjacent channels in a better way. Second, the GCN and LSTM are employed together to extract spatial–temporal features; the GCN is used to extract spatial features, while LSTM units are applied to extract temporal features. Finally, a softmax layer is applied to emotion classification. Main results. Extensive experiments are conducted on the A Dataset for Emotion Analysis using Physiological Signals (DEAP) and the SJTU Emotion EEG Dataset (SEED). The classification results of accuracy, precision, and F-score for valence and arousal dimensions on DEAP achieved 90.67% and 90.33%, 92.38% and 91.72%, and 91.34% and 90.86%, respectively. The accuracy, precision, and F-score of positive, neutral, and negative classifications reached 94.92%, 95.34%, and 94.17%, respectively, on the SEED dataset. Significance. The above results demonstrate that the proposed ERGL method is encouraging in comparison to state-of-the-art recognition research.

Novel reconstruction technique of omnipolar signals in high density electrode arrays

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – EU funding. Main funding source(s): National Research Program, Ministerio de Ciencia e Innovación, Spanish Government; Instituto de Salud Carlos III. Background Novel multi-electrode array catheters with equidistant spacing between the electrodes, have emerged in recent years - e.g. Advisor™ HD Grid Mapping Catheter, Sensor Enabled™ (SE). These systems typically use unipolar signals, sensitive to low-frequency noise, and bipolar signals - highly dependent on the direction of propagation. Thus, the full potential of these new devices is not yet fully exploited. We hypothesise that, a new clique (4-electrode in a squared 2x2 matrix) configuration for the computation of omnipolar signals allows to take full advantage of novel multi-electrode catheters, more robust to the direction of propagation of the wavefront against the one currently proposed in literature – thus helpful in the clinic given the challenging positioning of the catheter in the heart cavity during electrophysiologic studies. Methods In the current 3-electrode clique, the centre of the signal obtained does not correspond to the centre of the area of the clique, being less robust to wavefront propagation direction (see fig. 1A). A new configuration, the cross clique, is proposed for calculating the electrogram to improve the robustness and reduce the errors in the estimation local activation time (LAT) and others – see figure 1. One thousand simulated signals with stratified propagation angles and variable parameters were implemented to emulate flat waves and homogeneous propagation over cardiac tissue. The methods used to calculate the signal with the proposed shape are: obtaining the bipoles, 45 degree correction of the signal, detection of the propagation angle, rotation of the detected angle and estimation of the LAT. Results The average amplitude of the bipolar loop increased from the old triangular clique configuration: 600.36 ± 116.40 mV; to the novel one cross-clique: 840.47 ± 160.09 mV. Regarding the local activation time estimation, a decrease in the error is observed from the current omnipolar reconstruction: 207.50 ± 256.91 μs, to the one proposed 22.75 ± 29.426 μs. When the bEGM propagation angle estimation is activated, the angle estimation error is 2.77 ± 25.26o for the current reconstruction method, in contrast to 1.09 ± 11.35o in the proposed one – see figure 1B. Conclusion Our novel configuration considerably reduces the LAT estimation error and, on average, captures a larger signal amplitude than the classic triangular clique method. Thus, it allows using the full potential of new catheters, improving the omnipolar analysis. hen applying automatic angle detection to the methods, in the case of the traditional method, it is influenced by the desynchronisation of the components of the traditional model as it widens the bipolar EGM loop – see figure 1.B. Thus, a novel omnipolar reconstruction method is proposed to better estimate intracardiac EGMs, more robustly against the direction of the wavefront propagation. Further studies are under consideration with clinical signals.

Vegetative substrate configuration technology for tower foundation slope of transmission line in arid area considering species suitability

AbstractIn order to realize the ecological restoration of transmission line tower foundation slope and enrich the research methods of slope ecological restoration, this paper studies a nutrient matrix configuration technology for transmission line tower foundation slope in arid areas. The Xilingol arid grassland area in Inner Mongolia is selected as the research object, and plants such as Leymus chinensis, Festuca arundinacea and Agropyron pratense are selected as the grass species of the vegetative substrate configuration technology. Different proportions of water retaining agent, compound fertilizer, microbial agents and other substances are added to the soil, which are combined into 10 test groups. The effect of slope ecological restoration is verified by species suitability, physical and chemical properties of matrix and plant growth. The resβults showed that Caragana korshinskii, Artemisia annua, Astragalus adsurgens, Sonchus oleraceus and other plants are the dominant grass species in the plant substrate plants; The physical and chemical indexes of soil's bulk density, organic matter, total nitrogen and so on in group B2 are better than those in other groups. Adopting the vegetative substrate configuration technology with the proportion of group B2 can obtain a good ecological restoration effect of tower foundation slope of transmission line in arid areas. The vegetative substrate configuration technology can solve the long‐standing ecological and environmental protection problems of the tower foundation slope of transmission line in arid areas, and should be actively promoted and applied. Daur lymphatic is also widely used in ecological restoration of transmission line base slope in arid region. The average coverage rate was 14.85%. The average height was 100.5 cm. It could grow at an altitude of more than 1000 m. After the nutrient matrix of the transmission line base slope was configured, the grass planting belt was established under normal maintenance, and the seeds began to germinate 3 days later. After 10 days, the germination rate was 78% and the coverage rate was 65%.

Ultraflexible Organic Active Matrix Sensor Sheet for Tactile and Biosignal Monitoring

AbstractFlexible sensors are currently the subject of intensive research, as they allow cost‐effective and environmentally friendly production of large‐area, flexible, and when fabricated on ultrathin substrates, highly conformable devices. Among many intriguing applications, tactile and biosignal monitoring, where lightweight sensors with high wearing comfort are particularly interesting, is focused on here. The required spatiotemporal resolution of the signals is achieved by integrating the sensors in an active matrix configuration. Organic ferroelectric transducers of high uniformity, characterized, for example, by a sensitivity spread of only 1.5%, are combined with similarly uniform ultralow noise level organic thin film transistors operating below 5 V, showing, for example, a threshold voltage variation of just 0.13 V, in a 12 × 12 sensor array. The transistors transition frequency of up to 160 kHz (saturation range) and 17 kHz (linear range) allows for a high spatiotemporal resolution of ≈3 mm at a frame rate of 1400 fps. The thickness of only 2.8 µm renders the organic active matrix sensor sheet ultraflexible and therefore virtually imperceptible on the human skin. Real‐time monitoring of tactile modes in a subset of 8 × 3 pixels and of the pulse wave including heart rate and blood pressure using four sensors of the matrix is demonstrated.

Hydrodynamic Loads on a Group of Six Structures of Different Cross-Sections in Uniform and Sheared Flow

The estimates of hydrodynamic forces for a group of structures represent a challenge for the design of offshore systems, as they are subject to changes with a variation in flow profiles. The fluctuating effects may be more pronounced or, on the contrary, suppressed if the cross-sectional shape of structures in an array is altered. The present work performs a series of 2D numerical simulations for the flow past six identical stationary cylinders of three distinct geometrical shapes arranged in a 2 × 3 matrix configuration. The flow profiles considered have an averaged velocity corresponding to the critical flow regime of a Reynolds number of 2.5 × 105. The detached eddy simulation k–ω SST turbulence model is employed to perform a comprehensive investigation of the fluid force coefficients, their frequencies and vortex formation patterns. The effect of the spacing ratio varied simultaneously among the structures from 2 to 7 is considered in conjunction with the change in the flow profile and the cylinders’ cross-section. The results of simulations show a higher mean drag on the upstream cylinders, reduced mean drag on the mid- and downstream cylinders with the second cross-sectional shape, and a higher mean drag on the cylinders with the third cross-sectional shape, compared to the original circular cylinders.

Collective Behavior in Neuronal Networks with Electrical and Hybrid Synapses: Frequency Responses of Oscillations

We study synchronization through the combination of electrical synapse and hybrid synapse, and analyse frequency responses in a network constituted of two subnetworks (layers). We prove the onset of synchronization for two coupled nondelayed neurons when we set properly the coupling strength of electrical and chemical synapses, and neurotransmitter parameters of chemical synapse with constant initial conditions. The chemical synapse takes into consideration inhibitory and excitatory behaviors of the neuron. We further prove that for random initial conditions of few sets of identical nodes which constitute a network with two layers, global synchronization is possible for specific values of coupling strength and inner matrix configuration. To ensure great accuracy of the global synchronization, we add a controller and for all settings of electrical and chemical parameters, we always observe global synchronization in both layers and then, the associated network. Five different network topologies were used for the analysis. We finally verify the robustness of the global synchronization by using an external sinusoidal stimuli and observe that the control action is very powerful to maintain the global synchronization dynamic of the network. We observe equally that the instantaneous frequency can toggle between delta oscillations, awake state of the brain, up to gamma oscillations which are the frequencies of intensive activities of the brain.

Protective Effect of Cimicifuga racemosa (L.) Nutt Extract on Oocyte and Follicle Toxicity Induced by Doxorubicin during In Vitro Culture of Mice Ovaries

This study evaluated the potential of Cimicifuga racemosa (L.) Nutt extract (CIMI) to reduce the deleterious effects of doxorubicin (DOXO) in oocytes, follicles and stromal cells in mice ovaries cultured in vitro. In experiment 1, mice ovaries were cultured in DMEM+ alone or supplemented with 5, 50 or 500 ng/mL CIMI, while in experiment 2, mice ovaries were cultured in DMEM+ alone or supplemented with 5 ng/mL CIMI (better concentration), 0.3 μg/mL DOXO or both. Thereafter, the ovaries were processed for histological (morphology, growth, activation, extracellular matrix configuration and stromal cell density), immunohistochemical (caspase-3) analyses. Follicle viability was evaluated by fluorescence microscopy (ethidium homodimer-1 and calcein) while real-time PCR was performed to analyses the levels of (mRNA for SOD, CAT and nuclear factor erythroid 2-related factor 2 (NRF2) analyses. The results showed that DOXO reduces the percentage of normal follicles and the density of stromal cells in cultured ovaries, but these harmful effects were blocked by CIMI. The DOXO reduced the percentage of primordial follicles, while the presence of CIMI alone did not influence percentage of primordial follicles. A higher staining for caspase-3 was seen in ovaries cultured in control medium alone or with DOXO when compared with those cultured with CIMI alone or both CIMI and DOXO. In addition, follicles from ovaries cultured with both CIMI and DOXO were stained by calcein, while those follicles cultured with only DOXO were stained with ethidium homodimer-1. Furthermore, ovaries cultured with CIMI or both CIMI and DOXO had higher levels of mRNA for SOD and CAT, respectively, than those cultured with only DOXO. In conclusion, the extract of CIMI protects the ovaries against deleterious effects of DOXO on follicular survival and ovarian stromal cells.

Facile preparation of electrodes based on WO3 nanostructures modified with C and S used as anode materials for Li‐ion batteries

AbstractAn appropriate morphological and structure matrix configuration where lithium ions could insert and de‐insert is essential for lithium‐ion batteries (LiB). Tungsten oxides (WO3) are especially attractive materials for this aim. In this research, the effects of the morphology and composition of WO3 nanostructures on the charge/discharge behavior for Li‐ion batteries are methodically examined. On the one hand, nanostructured WO3 thin film was effectively synthesized by an electrochemical procedure. Then, an annealing treatment at 600°C in air environment for 4 h was carried out. In the second electrode synthesized, a carbon layer was uniformly deposited on WO3 nanostructures to obtain a WO3/C electrode. Finally, WO3/WS2 electrodes were prepared by means of in situ sulfurization of WO3 one‐step solid‐state synthesis using tungsten trioxide (WO3) and thiourea as precursor material. By using X‐ray photoelectron spectroscopy, X‐ray diffraction analysis, transmission electron microscopy, Raman spectra, and field‐emission scanning electron microscopy, the three electrodes have been morphologically characterized. Electrochemical properties were analyzed by cyclic voltammogram, galvanostatic charge/discharge cycling, and electrochemical impedance spectroscopy. Among all the synthesized samples, WO3/C nanostructures reveal the best performance as they exhibit the greatest discharge capacity and cycle performance (820 mA h g−1).

Strength of RC Beam Using Geo Polymer Concrete and Adoption Bubble Technology

Abstract: Bubble Deck technology first time in European countries provide consumption of high-density polyethylene hollow spheres to replicate the unproductive material in the mid of the slab, consequently diminishing the deceased burden and escalating the competence of the flooring. This process be used in the concrete floor system. Concrete is superior in firmness and thus is further constructive in the compression section than in the tension section. The diminution in concrete can be done by replacing the tension region concrete. Keeping the equal design in intellect, an effort has been ended to discover out the efficiency of plastic bubbles by replacing concrete in the tension region of Ordinary Portland Cement Concrete (OPCC) and Geo polymer Concrete (GPC) beam. Geo polymer Concrete does not figure calcium- silicate-hydrates (CSHs) for matrix configuration and potency like OPCC however utilizes the poly condensation of silica with alumina precursors to achieve structural potency. In this job, M25 concrete mix is used to practice both OPCC and GPC beams. The trial mix is experienced for compressive potency. Flexure test is completed for 28 days of curing of the beams.

Quantification of greenhouse gas emissions of a steel factory in Brazil

his work aimed to identify and quantify greenhouse gases (GHG) emissions of a steel factory, considering the importance of these data in the context of large global GHG emissions. As a result, Scope 1 emissions were identified as the highest in the industry, representing more than 89% of total emissions in CO2eq. This scenario is mainly identified a result of the Brazilian energy matrix configuration, which contributes to reduce Scope 2 emissions. The used methodology (GHG Protocol v. 2018.1.4) proved to be appropriate for calculating emissions within a broader report (annual amount). However, in order to develop an indicator for the organization, with monthly detailed data, it was necessary to adapt the tool, which is the differential of this work.

Effect of the water matrix and reactor configuration on Enterococcus sp. inactivation by UV-A activated PMS or H2O2

In this work, the influence of the matrix on the photolytic activation of peroxymonosulfate (PMS) and hydrogen peroxide (H2O2) has been studied for the inactivation of Enterococcus sp. Additionally, two different reactor configurations (batch reactor and tubular reactor) have been evaluated that achieve complete disinfection within 120 min when using a tubular reactor. Three water matrices (distilled water, saline solution and simulated wastewater) have been studied, and experiments have been carried out using radical scavengers to determine the main reactive species involved in each process. The hydroxyl radical (OH) has been found to be the main responsible for the inactivation of bacteria in distilled water, while chlorinated species generated during treatments are responsible for disinfection in a saline matrix. The study of the influence of various inorganic ions (Br−, F−, PO43−, NO3−, NO2−) on treatments revealed an increase in the efficacy of the PMS/UV-A system in the presence of Br− due to the bromine generation. Furthermore, the effect of F− has been studied for the first time, determining that the presence of this compound does not have a significant influence on the H2O2/UV-A system while inhibiting PMS/UV-A treatment. Overall, the results suggest that H2O2-based treatments would be less dependent on matrix composition than those involving PMS, and the presence of nitrites is a contraindication to the application of either process.

One-Body Two-Dimensional Switching Matrices With a Triangular Lattice of Beams

This letter presents a numerical design method of one-body two-dimensional (2-D) switching matrices with a triangular lattice of an arbitrary number of beams in each of horizontal and vertical directions, improving the overlap between the beams in a 2-D multiple-beam coverage. With the proposed matrix configuration, the minimum number of cascaded units consisting of a mix of 1-D and 2-D couplers and phase shifters is found to be smaller than that of the conventional cascade of 1-D matrices when the number of beams is larger than three in either of horizontal or vertical directions. The proposed solution is of interest for millimeter-wave applications requiring spatial diversity.

Relationship between alien plant invasion and landscape matrix in the water-level fluctuating zone of the Three Gorges Reservoir, China.

Invasive process of alien species is affected by not only the invaded habitats, but also the surrounding landscape matrix. Understanding the effects of landscape matrix on alien species is of great significance for controlling invasive alien species. We surveyed plant communities along the water-level fluctuating zone (WLFZ) of the Three Gorges Reservoir. Invasive status of alien plant species was evaluated. Totally 10 spatial scales of the surrounding landscape matrix in the scope of 2000 m (including WLFZ) were classified, and 14 landscape indices were applied to analyze the landscape matrix composition and configuration. Using the principal component analysis and correlation analysis, the effects of landscape matrix on the alien invasive plant species and associated scale effect were tested. Results showed that a total of 42 alien invasive plant species were found in the WLFZ, belonging to 17 families and 36 genera. Fuling was a dividing place to differentiate invasive species distribution. The number of the alien invasive species between Fuling and the Three Gorges Dam was found more than that between Fuling and Jiangjin. For the all scales (within 2000 m). The higher the landscape matrix fragmentation was, the more difficult the alien species invading. The higher landscape connectivity was, the easier the alien species invading. The effects of landscape matrix composition and configuration on the invasive plant diversity at large scales (1200-2000 m) was more significant than those at small scales (200-1000 m), in which landscape matrix composition and configuration at 1200-1400 m showed the strongest effect, demonstrating a significant spatial scale effect. Different invasive plant species showed the scale effects of landscape matrix composition and configuration. At all scales, Xanthium strumarium and Bidens frondosa showed weak correlations with landscape indices, but Bidens tripartita and Erigeron canadensis showed strong correlations. Landscape matrix was closely related to invasive plant species, and demonstrated a significant scale effect. The alien invasive plant species could be traced to the landscape matrix at large scales. Grassland and forest patches at the small scales could be used as the 'stepping stone' for the alien species transiting before they arrived at the WLFZ. In order to control alien plants in the WLFZ, land-use management and optimization should be strengthened at different scales of landscape matrix on the basis of enhancement of habitat management. A diversified comprehensive control for alien species should thus be taken into account.

A review of avian experimental translocations that measure movement through human-modified landscapes

Understanding how landscape characteristics such as matrix composition and configuration affect bird movement is essential for conservation in human-disturbed habitats. An important tool for such studies is experimental translocation, in which birds are removed from their territories, and observed, often using radio telemetry, as to whether they return (“home”). Here we reviewed 28 translocation studies to investigate (1) in what regions and habitats, and with what species the technique has been used, (2) what proportion of birds fail to home, a measure of “bird safety”, (3) the findings the studies have uncovered about bird movement, and (4) how the studies have dealt with confounding variables. A phylogenetically controlled meta-analysis complemented the qualitative results, testing the effects of the species’ habitat usage and migration ecology on the difference between birds’ homing success when moving through contiguous forest as compared to other land-use types. Of the total sample, 25 studies were conducted in the Western Hemisphere, and 17 in locations where pasturelands were the dominant land-use. The technique has been mostly used with small, forest-preferring passerine species, and males. Regarding safety, the proportion of individuals that failed to home was 27.1 ± 21.8 (SD)%. Translocation distance was found to be an important predictor of homing time or success in seven studies. The meta-analysis confirmed that on average birds move better through contiguous forests than through other land-use types, with habitat generalists and species with seasonal migration having less trouble moving through disturbed land-use types. The qualitative analyses also demonstrated the importance of habitat usage, with forest specialists especially affected by forest cover and connectivity. In considering the utility of translocations, it is important to remember that they are not measuring juvenile dispersal, and the birds’ homing mechanisms might influence their movements. However, long-distance translocations can avoid homing and hence simulate breeding (adult) dispersal. The confounding effects of variation among capture and release sites, or among individuals in their physiological condition, must be carefully considered. Overall, experimental translocation is a mature technique for which possible pitfalls have been identified. Strengths of the approach are that bird motivations to move can be standardized, and fine-scale movement patterns can be described with telemetry. However, we encourage consideration of bird safety, and meticulous reporting of birds that fail to home, or fail to find suitable habitat in long-distance translocation designs. • Translocated birds either home to their territories or move to suitable habitat. • 28 studies mostly in Western hemisphere and with male forest-preferring passerines. • Meta-analysis shows birds are most successful in moving through contiguous forest. • Migrant species show less of a difference between forest and other land-types. • The technique has known weaknesses, but also strengths, and few alternatives.