Effects Of Various Disturbances Research Articles

Difference in acoustic responses to urbanisation in two African passerines

Modification of ecosystems as a consequence of urbanisation alters natural habitat structures and soundscapes, creating constraints for vocal communication in animals. Birds are able to adjust their vocalisation to the prevailing acoustic features of their habitat. As such, their sounds have been shown to reflect the level of anthropogenic disturbances across landscapes. While the effect of a single anthropogenic disturbance like ambient noise on birds’ vocal communication is widely investigated, the combined effects of various disturbances remain less explored. We tested single and combined effects of anthropogenic noise and urban physical structures on the vocalisations of two African passerines, the Common Bulbul Pycnonotus barbatus and Northern Grey-headed Sparrow Passer griseus. We predicted that (i) both species would increase the minimum frequency of their vocalisation to avoid masking by ambient noise, (ii) both species would decrease their maximum frequency to evade distortion by physical structures, (iii) the two urban components would have a significant combined effect on the vocalisations, and (iv) the change in minimum or maximum frequency will lead to a corresponding change in the vocalisation bandwidth. For the Common Bulbul, the minimum frequency increased significantly as the ambient noise level increased, but the maximum frequency did not change in response to urban physical structures. For the Northern Grey-headed Sparrow, the minimum frequency did not show a response to ambient noise, but the maximum frequency decreased significantly as physical structures and ambient noise increased. We did not find any evidence for a combined effect of urban physical structures and ambient noise on the vocal adjustment of either species. A change in either the minimum or maximum frequency resulted in a corresponding change in the vocalisation bandwidth of each species. Our findings highlight how the same vocalisation traits of different songbird species can be affected differently by novel selective pressures in acoustic communication that arise in urban environments.

Finite-Time Model-Free Adaptive Control for Discrete-Time Nonlinear Systems

This paper addresses the fast trajectory tracking problem for discrete-time nonlinear systems, and whereby a finite-time model-free adaptive control (FMFAC) approach is innovatively devised. Here, the nonlinear systems’ dynamics are completely unknown and the widespread disturbances are considered. The nonparametric dynamic linearization technique and the adaptive extended disturbance observer are firstly deployed to achieve real-time linearization of the discrete-time nonlinear system, and an efficient finite-time performance index function is thereafter devised, and thereby contributing to a novel FMFAC control scheme. Theoretical analysis indicates the finite-time model-free tracking control within a stable region can be guaranteed, and the boundedness of the control input signal can be ensured rigorously, even though under the effect of various disturbances. The key points of the proposed FMFAC approach are model-free and possessing the fast regulation ability, and the corresponding effectiveness and superiority are validated via simulation studies.

Development and Rotation Characteristics Analysis of a Large-Scale Deployable Arm

In the spin-off acceleration stage during high-speed rotation in space, the deployable arm of the space gravity simulation device must withstand a large axial centrifugal force and a driving torque. In this paper, a large-scale high-speed rotating deployable arm is proposed, and the relevant characteristics during the rotation process are analyzed. A new driving mode of towed deployment is proposed that can lead to the rapid and efficient deployment of a large-scale deployable arm. First, an optimized configuration of a deployable arm is proposed. Second, the deployment driving process of the deployable arm under several different drag driving modes is simulated and analyzed, and a comparative analysis is performed to select a simple and reliable drag deployment driving scheme. Then, the effects of various disturbances on the posture of the deployable arm during the rotation process are explored, guiding the posture control of the deployable arm. Finally, a 10 m four-unit prototype is developed for the stiffness and rotation tests, which verify that the theoretical analysis in this paper is correct.

The combined effect of short-term hydrological and N-fertilization manipulation of wetlands on CO2, CH4, and N2O emissions

Freshwater wetlands are natural sinks of carbon; yet, wetland conversion for agricultural uses can shift these carbon sinks into large sources of greenhouse gases. We know that the anthropogenic alteration of wetland hydrology and the broad use of N-fertilizers can modify biogeochemical cycling, however, the extent of their combined effect on greenhouse gases exchange still needs further research. Moreover, there has been recent interest in wetlands rehabilitation and preservation by improving natural water flow and by seeking alternative solutions to nutrient inputs. In a microcosm setting, we experimentally exposed soils to three inundation treatments (Inundated, Moist, Drained) and a nutrient treatment by adding high nitrogen load (300 kg ha−1) to simulate physical and chemical disturbances. After, we measured the depth microprofiles of N2O and O2 concentration and CO2 and CH4 emission rates to determine how hydrological alteration and nitrogen input affect carbon and nitrogen cycling processes in inland wetland soils. Compared to the Control soils, N-fertilizer increased CO2 emissions by 40% in Drained conditions and increased CH4 emissions in Inundated soils over 90%. N2O emissions from Moist and Inundated soils enriched with nitrogen increased by 17.4 and 18-fold, respectively. Overall, the combination of physical and chemical disturbances increased the Global Warming Potential (GWP) by 7.5-fold. The first response of hydrological rehabilitation, while typically valuable for CO2 emission reduction, amplified CH4 and N2O emissions when combined with high nitrogen inputs. Therefore, this research highlights the importance of evaluating the potential interactive effects of various disturbances on biogeochemical processes when devising rehabilitation plans to rehabilitate degraded wetlands.

Dynamic analysis of the center position control and design of disturbance observers during annealing and pickling

In this study, we propose a new center position controller (CPC) to control the center position error (CPE) of the steel strip during the annealing and pickling processes. The model of the nonlinear CPC system is described for two adjacent rolls and extended to multifeed rolls. We derive a linearized discrete state equation for the multi CPC and analyze its characteristics. A simulator of the CPC system that includes rollers, actuators, and plant data is developed to test the dynamics of the CPC. In addition, a disturbance observer with a low pass filter Q(s) is designed to minimize the effects of various disturbances. The order and time constant of the filter are selected in consideration of the order of the system and the response of the actuator. Results of the offline tests show that the CPE is greatly decreased by the proposed control technology.

Abiotic disturbances affect forest short-term vegetation cover and phenology in Southwest China

Forest disturbances significantly affect the global carbon cycle by, for example, vegetation loss or changing forest phenology. However, the lack of historical disturbance events constitutes a challenge for in-depth temporal and spatial analysis. Available remote sensing time series and combined climate data may have great potential to quickly and consistently detect and identify forest disturbances events. We employed time-series data (2001–2014) of a vegetation index (normalized difference vegetation index, NDVI) and a change detection algorithm (the breaks for additive seasonal and trend, BFAST) to detect forest disturbances in a sub-tropical area located in Southwest China. Remote sensing and meteorological data were combined to distinguish among the typical forest disturbances: fires, extreme cold events in winter (ECE), and droughts. With the reconstructed historical disturbance events, post-disturbance vegetation loss, short-term vegetation cover, and phenology changes were analyzed. Our results show that fires and droughts caused severe damage to forest cover (NDVI anomalies can reach up to −1.84 and −1.11, respectively). Fire changed the regular phenological periods which last 3–4 years, and it also took 1–2 years for vegetation greenness to recover after ECE and droughts, which triggered carbon emissions and reduced forest stocks. Warmer areas were vulnerable to ECE effects as well and should be paid more attention. Post-disturbance effects show complex patterns: characteristics of disturbances, climatic conditions, and multiple events overlaying contribute to modifying forest vegetation. Hence, forest disturbances cannot be neglected but should be emphasized in future forest ecosystem modeling or analyzing. The approach used in the study can be a crucial step in detecting and assessing the effects of various disturbances on forest vegetation and phenology and, thereby, contributes to improved risk analysis and management in forestry.

Use of drilling performance to improve rock-breakage efficiencies: A part of mine-to-mill optimization studies in a hard-rock mine

In a hard-rock mine, blasting is an important rock-breakage process that impacts energy consumption both in downstream comminution processes and mine productivity. Optimizing the blast fragmentation to improve rock-breakage efficiencies during crushing and grinding is key to mine-to-mill (MTM) optimization. This study explores the use of monitoring while drilling (MWD) data to achieve this goal. Representative penetration rates (PRs) were extracted from blastholes to estimate intact rock properties and predict the breakage efficiencies that directly affect comminution energy consumption. Two intact rock properties, tensile strength (TS) and Bond work index (BWI), were correlated with the PR data to predict these efficiencies in crushing and grinding, respectively. Because of the complexity of the raw MWD data and effects of various disturbances, the MWD data was preprocessed and normalized to achieve a representative PR value at each blasthole. This preprocessing entailed defining valid PR ranges from the MWD data that could eliminate the noise related to discontinuity features in the rock mass structure as well as errors in operator behaviors. The PR data was also normalized using the adjusted penetration rate (APR) to minimize the effects of mechanical factors such as drill feed force, torque, and rotational speed. To correlate the representative APR value with intact rock properties, TS and BWI, various laboratory experiments were conducted: drilling tests using a high-precision coring machine, Brazilian disc tests, and Bond grindability tests. Based on the results of these experiments, models were developed to predict rock-breakage efficiencies during crushing and grinding based on APR. The result of this study can be used to obtain blast energy designs that consider comminution energy consumption and efficiency in the downstream rock-breakage processes.

Anthropogenic disturbances alter the conservation value of karst dolines

Dolines are depressions in karst landscapes that are of high value for conservation, providing habitats and supporting species not found in the surrounding landscape. This is due to their high microhabitat diversity and ability to decouple microclimate from regional climate changes, making them potential refugia for biodiversity. Nevertheless, local anthropogenic disturbances have had considerable impact on the species composition and vegetation structure of many dolines. Here we investigate the conservation value of dolines in three European karst areas, where different levels and types of anthropogenic disturbances have been shaping the vegetation for centuries, using the number of plant species that are cool-adapted, moist-adapted and of high conservation importance (i.e. vulnerable species) as indicators. We found that anthropogenic disturbances generally have a negative impact, reducing the number of vulnerable species supported by dolines. However, more cool-adapted and moist-adapted species were found in some dolines planted with non-native Picea abies than in less disturbed dolines, indicating that anthropogenic disturbances can also have positive consequences for biodiversity. We conclude that anthropogenic disturbances alter the capacity of dolines to support vulnerable species, and that this will impact survival of species in landscapes under global warming. In this context, the effects of various disturbances on species composition and diversity need to carefully considered to determine the best conservation and/or management options.

Research of the Photoelectric Tracking and Pointing Platform Based on the Servo Control System

To improve the speed and accuracy of the photoelectric tracking and pointing platform stable tracking, we took the three-axis photoelectric tracking platform, of which the coupling among the rings is ignored, as the research object. Considering the effects of various disturbances, the stable tracking double closed-loop servo control system was built for the azimuth, pitch, and roll rings. In the stabilization loop, output-feedback H∞ controller based on linear matrix inequality was designed to reduce the effects of model perturbations and uncertainties and to maintain the stability of the platform’s inertial space. In the tracking loop, the integral-separation proportional integral derivative (PID) controller was designed to achieve fast and accurate tracking. Smith estimated compensation was adopted to compensate the pure lag caused by video tracking. Finally, the double closed-loop servo control system was built to complete the simulation. The simulation results show that the system not only has good robustness under external disturbances, but also completes the attitude tracking quickly and accurately. Besides, the tracking error is |error| < 5∙e-4 rad, which meets the tracking accuracy requirements.

The effect of various disturbances on the seeds on the content of chlorophyll a, chlorophyll b, carotenoids, and biomass of cayenne pepper Seedlings

Study on the effect of various disturbances on the cayenne pepper seeds (Capsicum Frutescens L.) to the content of chlorophyll a, chlorophyll b, carotenoids, and biomass of the plants in the germination period have been done. The disturbances given include UV-C irradiation for 1 hour (S1), microgravity for 12 hours (S2), for 24 hours (S3), and for 48 hours (S4), as well as combined disturbances that are UV-C irradiation for 1 hour followed by microgravity for 12 hours (S5), for 24 hours (S6), and for 48 hours (S7). As comparison, it has been used seeds without treatment called control (S0). The microgravity environment was created using a 2-D clinostat with a rotational speed of 2.7 rpm (1.2 x 10-4 g). All samples were grown in normal gravity (1 g) environment. Observations were made during the vegetative phase until the plant was 40 days old. Measurements of chlorophyll a, chlorophyll b, carotenoids, and biomass were performed at the plants were 10, 20, and 40 days old. The results showed that disturbances which given on the seeds gave positive effects on the content of chlorophyll a, chlorophyll b, carotenoids, and biomass of the plants. The impacts depend on the duration of the disturbances given.

Error probability model for IEEE 802.15.4 wireless communications in the presence of co-channel interference

The IEEE 802.15.4 standard is the most widely used for the realization of Wireless Sensor Networks (WSN) and Internet of Things (IoT) applications. The effects of various disturbances on IEEE 802.15.4 wireless transmissions in the 2.4 GHz band have been studied previously for background noise, multipath fading, wideband and narrowband interference caused by WiFi and Bluetooth networks. The influence of co-channel interference, which originates from collisions between IEEE 802.15.4 devices which perform simultaneous radio transmission, has not been investigated previously. The IEEE 802.15.4 standard uses the Carrier Sense Medium Access with Collision Avoidance (CSMA/CA) channel access mechanism to prevent collisions between devices, but this mechanism does not provide protection from a hidden node problem, which is the primary source of co-channel interference. Hidden node collision in the CSMA/CA channel access mechanism occurs because of the time-spatial relation between nodes located inside the radio range of the recipient device. In our paper, we determined the spatial probability for k-tuple of mutually hidden nodes using the Monte Carlo simulation method. Furthermore, we analyzed the influence of co-channel interference on the error probability of IEEE 802.15.4 communication, and derived accurate analytical models by considering the non-ideal features of the used spreading sequences. The accuracy of the derived mathematical models was tested by numerical Monte Carlo simulation of the IEEE 802.15.4 communication and in a real-world experiment using IEEE 802.15.4 compliant wireless transceivers for creating co-channel interference. The presented simulation and real world experiment results show consistency with the proposed analytical error probability models.

Assessment of tree mortality on the Estonian Network of Forest Research Plots/ Puude väljalangevuse hindamine metsa kasvukäigu püsiproovitükkidel

Abstract Assessment of tree mortality provides deeper understanding of forest structure and functioning. This enables evaluation of stand sustainability and provides information on stand productivity, diversity and health condition. Tree mortality can be assessed by spatiotemporal patterns as well as by studying the processes and causes of mortality. Tree mortality is caused by specific disturbance agents or by the complex effect of various disturbances. The purpose of this study is to examine tree mortality in Estonian forests, determine the causes of tree death, and estimate how different management regimes affect tree mortality and its causes. This study is based on 360 sample plots measured in 2003-2005 and re-measured in 2008-2010. The sample plots were divided into recently managed (RM, 146 plots) and low intensity/unmanaged (LU, 214 plots) plots based on forest management regime. In total, 53,990 trees were measured, of which 20,020 were located on RM and 33,970 on LU plots. The tree mortality for 5-year period was 3.4% on RM plots and 8.0% on LU plots. The main cause of tree mortality in RM stands was insect damage, which attributes to 29.8% of tree mortality, whereas in LU stands the main cause was tree competition, which attributes to 45.4% of tree mortality. The analysis of tree mortality indicated that an increase in relative tree diameter in both stand types contributes to an increase in mortality due to insect, wind or fungal damage and diseases. Opposite results were received with respect to competition - the smaller the tree relative diameter, the more probable it is that a tree will die because of competition with neighbouring trees. The analysis of game damage and other causes of tree mortality showed that these were not dependent on the relative diameter of trees. The analysis of the overall probability of tree mortality revealed that relatively smaller trees have a higher probability of mortality than larger trees.

Accurate image capturing control of bottle caps based on iterative learning control and Kalman filtering

This paper investigates camera control for capturing bottle cap target images in the fault-detection system of an industrial production line. The main purpose is to identify the targeted bottle caps accurately in real time from the images. This is achieved by combining iterative learning control and Kalman filtering to reduce the effect of various disturbances introduced into the detection system. A mathematical model, together with a physical simulation platform is established based on the actual production requirements, and the convergence properties of the model are analyzed. It is shown that the proposed method enables accurate real-time control of the camera, and further, the gain range of the learning rule is also obtained. The numerical simulation and experimental results confirm that the proposed method can not only reduce the effect of repeatable disturbances but also non-repeatable ones.

Canopy stomatal conductance following drought, disturbance, and death in an upland oak/pine forest of the new jersey pine barrens, USA.

Stomatal conductance controls carbon and water fluxes in forest ecosystems. Therefore, its accurate characterization in land-surface flux models is necessary. Sap-flux scaled canopy conductance was used to evaluate the effect of drought, disturbance, and mortality of three oak species (Quercus prinus, Q. velutina, and Q. coccinea) in an upland oak/pine stand in the New Jersey Pine Barrens from 2005 to 2008. Canopy conductance (GC) was analyzed by performing boundary line analysis and selecting for the highest value under a given light condition. Regressing GC with the driving force vapor pressure deficit (VPD) resulted in reference canopy conductance at 1 kPa VPD (GCref). Predictably, drought in 2006 caused GCref to decline. Q. prinus GCref was least affected, followed by Q. coccinea, with Q. velutina having the highest reductions in GCref. A defoliation event in 2007 caused GCref to increase due to reduced leaf area and a possible increase in water availability. In Q. prinus, GCref quadrupled, while doubling in Q. velutina, and increasing by 50% in Q. coccinea. Tree mortality in 2008 led to higher GCref in the remaining Q. prinus but not in Q. velutina or Q. coccinea. Comparing light response curves of canopy conductance (GCref) and stomatal conductance (gS) derived from gas-exchange measurements showed marked differences in behavior. Canopy GCref failed to saturate under ambient light conditions whereas leaf-level gS saturated at 1,200 μmol m−2 s−1. The results presented here emphasize the differential responses of leaf and canopy-level conductance to saturating light conditions and the effects of various disturbances (drought, defoliation, and mortality) on the carbon and water balance of an oak-dominated forest.

A mathematical model of homeostatic regulation of sleep-wake cycles by hypocretin/orexin

Event Abstract Back to Event A mathematical model of homeostatic regulation of sleep-wake cycles by hypocretin/orexin Svetlana Postnova1*, Karlheinz Voigt1 and Albert Braun-Hans1 1 University of Marburg, Department of Physiology, Germany A generally accepted concept of sleep regulation postulates that sleep-wake transitions result from the interaction between circadian and homeostatic processes. The circadian process is ascribed to the activity of the suprachiasmatic nucleus of the hypothalamus, while the mechanism of the homeostati c process are still unclear. In this study we present a concept of hypocretin/orexin-based control of sleep homeostasis. Hypocretin/orexin (hcrt/orx) is a neuropeptide which is produced in the lateral hypothalamus and its absence leads to the well-known sleep disorder narcolepsy. We propose that 1) high frequent impulse activity of the hcrt/ox neurons during the wake state is sustained by reciprocal excitatory connections with other, e.g. local glutamate neurons; 2) the transition to a silent state (sleep) is going along with a weakening of the hcrt/ox synaptic efficacy. This concept has been realized in a mathematical model with Hodgkin-Huxley-type neurons and physiology-based synapses. The model is capable to simulate the neuronal activity which corresponds to the sleep-wake transitions and the effects of various disturbances. It offers a new approach for further evaluation of the physiological, especially homeostatic mechanisms of sleep-wake cycles on the basis of neuronal activity and synaptic transmission. The work was supported by the European Union through the Network of Excellence BioSim contract No LSHB-CT-2004-005137. Conference: Neuroinformatics 2009, Pilsen, Czechia, 6 Sep - 8 Sep, 2009. Presentation Type: Poster Presentation Topic: Computational neuroscience Citation: Postnova S, Voigt K and Braun-Hans A (2019). A mathematical model of homeostatic regulation of sleep-wake cycles by hypocretin/orexin. Front. Neuroinform. Conference Abstract: Neuroinformatics 2009. doi: 10.3389/conf.neuro.11.2009.08.112 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 25 May 2009; Published Online: 09 May 2019. * Correspondence: Svetlana Postnova, University of Marburg, Department of Physiology, Marburg, Germany, postnova@staff.uni-marburg.de Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Svetlana Postnova Karlheinz Voigt Albert Braun-Hans Google Svetlana Postnova Karlheinz Voigt Albert Braun-Hans Google Scholar Svetlana Postnova Karlheinz Voigt Albert Braun-Hans PubMed Svetlana Postnova Karlheinz Voigt Albert Braun-Hans Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Skin Friction Measurements Using Oil-Film Interferometry in NASA's 11-Foot Transonic Wind Tunnel

Skin-friction measurements were obtained on two laminar flow airfoils in the NASA Ames 11-ft transonic wind tunnel using oil-film interferometry. Improvements in the experimental technique allowed skin-friction measurements at two conditions per run in conjunction with performance testing, thus reducing the impact on the run schedule. Quantitative measurements of skin friction were used to determine transition location and the extent of separation (if any) on the airfoils providing much more insight into the flow than flow viz. The technique has been extended to obtain a quantitative measure of shear in the reversed flow region. The effects of various disturbances to the boundary layer were also investigated. Laminar flow was found as far back as 60% chord at a Reynolds number of 4.5 x 10 6 .

A mechatronics approach to laser powder deposition process

This paper introduces a mechatronics approach for the development of a closed-loop control system utilized in laser powder deposition. The laser powder deposition process, as a manufacturing technique, is combined with a feedback control system to increase the quality of the final formed parts. The interconnections between the technologies involved in this complex mechatronics system along with the development of a CCD-based optical detector are explained. The optical CCD-based detector monitors the process zone to provide a series of single pass band images of the near-locus region. A pattern recognition algorithm is incorporated into the feedback device to obtain the clad’s height and angle of solid/liquid interface in real-time. This feedback device is blended in a PID-based controller, which is designed using a knowledge-based model, to adjust the laser pulse energy for enhancing the output of the process. The experimental assessments of the developed system are also presented at different process conditions and disturbances when Fe–20%Al was deposited on mild steel. It is shown that the PID-based controller can effectively improve the geometrical characteristics of the clad around the operating point by overcoming the effects of various disturbances.

Simulating the effects of prescribed burning on fuel loading and timber production (EcoFL) in managed northern Wisconsin forests

We developed a fuel loading prediction model (EcoFL), which quantified fuel loads at ecosystem level using a classical ecosystem productivity concept and aboveground biomass measurements. EcoFL predicted fuel loading with high precision ( r 2 = 0.94), but the linear relationship between measured and predicted was slightly off from the 1:1 line (slope = 0.86–1.17). The study showed a possibility of developing landscape level fuel loading model. EcoFL indicated that carbon allocation had to be parameterized accurately to predict fuel loading precisely. Prescribed burning has been widely used to reduce fuel and promote ecosystem functions throughout the United States, but the long-term ecological impacts of prescribed burning are widely unknown. We evaluated the effect of alternative prescribed burning rotations (ROT), magnitude in productivity reduction by prescribed burning (MAG), and duration of productivity reduction (DUR) on fuel loading (Mg ha −1) and timber production (Mg ha −1) in managed northern hardwood, red pine ( Pinus resinosa), and jack pine ( P. banksiana) forests in northern Wisconsin. The results showed that DUR would be the most critical information when deciding ROT in order to preserve timber production and to maintain low fuel loading. The results implied that forest productivity could reduce timber production drastically, if ROT was shorter than DUR and ecosystem productivity was affected cumulatively by prescribed burning. Under a 5-year ROT, the harvested biomass was reduced up to 17.9, 30.4, and 25.5%, respectively, of controls in hardwood, red pine, and jack pine forests. For accurate long-term prediction of prescribed burning, substantial field data are still needed to identify productivity recovery pattern, carbon allocation after burning, and long-term effect of burning on productivity. EcoFL has the potential to be used for evaluating the effect of various disturbances (e.g., thinning, harvesting) on fuel loading, and the output of EcoFL can be used as an input data for fire spread models. The results of this study will be fundamental for forest managers to balance the timber production and fuel reduction using prescribed burning.

Ground spider diversity in the Kenting uplifted coral reef forest, Taiwan: a comparison between habitats receiving various disturbances

The effects of various disturbances on diversity and community structures of ground spiders in the Kenting National Park uplifted coral reef forest were investigated using pitfall traps. In each of the following five sampling sites, ten trap stations were established and were monitored once every month for a whole year: primary forest, primary forest with tourism activities, secondary forest, grassland with tourism activities and abandoned grassland. A total of 2237 adult spiders from 20 families and 110 species were collected, among which 86 (78.2%) were new or newly recorded species to Taiwan. Dominant species can be divided into two major groups according to temporal abundance variations: abundant in the dry season and abundant in the wet season. Habitat preference of 12 dominant species was assessed by comparing their relative abundance between sampling sites. Half of the species exhibited strong habitat preference and two species could only be found in habitats receiving no tourism disturbance. The Shannon–Weaver function, Simpson index and Evenness were not significantly different among the sites, suggesting that these sites had a similar community structure characterized by few dominant species and numerous rare species. However, the species composition differed considerably among the five sites. Results of a UPGMA analysis using pairwise Euclidean distance demonstrated that specimens from 50 trap stations can be divided into four major clusters: primary forest, secondary forest, grassland I and grassland II. Also, among 110 species obtained, 61 were distributed in one sampling site only, and each site had between 11 and 16 unique species. In addition to species composition, foraging guild composition also differed significantly among sampling sites. These results suggest that the diversity of ground spiders in the KTNP uplifted coral reef forest is quite heterogeneous, and any management activity should consider the uniqueness of each habitat type.

Effect of Various Disturbances on fMRI: A Study on Visual and Motor Cortices

We have studied the effects of various disturbances of two different levels of difficulty, that is, with weak and with strong difficulty levels for primary visual and motor tasks. In the case of visual task with motor and mental disturbances, we found it decreased as motor and mental disturbance difficulty-level increased, ***compared with the cases without motor and mental disturbances. To the contrary, in the case of motor activity, the total activation of motor cortex with weak and with strong mental disturbance was increased as mental disturbance difficulty-levels increased.