Assessing the reduction of the hydrological connectivity of gully systems through vegetation restoration: field experiments and numerical modelling

Restoration of degraded land in the Southern Ecuadorian Andes has led to alterations in the functioning of degraded catchments. Recovery of vegetation on areas affected by overgrazing, as well as the reforestation or afforestation of gully areas have given rise to modifications of hydrological connectivity within the catchments. Recent research has highlighted the ability of gully channels to trap sediment eroded from steep slopes, especially if vegetation is established along the gully bed. However, vegetation cover not only induces sediment deposition in the gully bed, but may also have a potential to reduce runoff water volume. The performance of gully beds in reducing the transfer of runoff was investigated by conducting controlled concentrated flow experiments in the field. Experimental field data for nine gullies were derived by pouring concentrated inflow into the upstream end and measuring the outflow at the downstream end of the channel. Two consecutive flow experiments per gully were carried out, so that data for dry and wet soil conditions were collected. The hydrological response to concentrated flow was estimated for each experiment by calculating its cumulative infiltration coefficient, <i>IC</i> (%). The results showed a great difference in <i>IC</i> between dry and wet soil conditions. The <i>IC</i> for wet soil conditions was on average 24%, whereas it was 60% for dry conditions. Gullies with more than 50% surface vegetation cover exhibit the highest cumulative infiltration coefficients (81% for dry runs, and 34% for wet runs), but runoff transmission losses were not as clearly related to vegetation cover as sediment storage as shown in Molina et al. (2009). The experimental field data of 16 experiments were used to calibrate a hydrological model developed by Fiener and Auerswald (2005) in order to simulate the transfer of concentrated flow along the gully beds. The calibrated model was able to simulate the transfer of runoff water well, as the error on the simulated total outflow volumes is below 13% for 15 out of 16 cases. However, predicting infiltration amounts is difficult: the high sensitivity of model results to some crucial hydraulic parameters (runoff width, hydraulic conductivity and sorptivity) is one of the reasons why the relationships between model parameter values and gully features are relatively weak. <br><br> The results obtained from the field experiments show that gully systems are key elements in the hydrological connectivity of degraded landscapes. The transfer of overland flow and sediment from the slopes towards the river system highly depends on the presence/absence of vegetation in the gully beds and should therefore be accounted for in assessments of landscape degradation and/or recovery

Mountains of our future Earth: Defining priorities for mountain research

The Perth conferences, held every 5 years in Perth, Scotland, bring together people who identify as mountain researchers and who are interested in issues related to global change in mountain social-ecological systems. These conferences provide an opportunity to evaluate the evolution of research directions within the mountain research community, as well as to identify research priorities. The Future Earth Strategic Research Agenda provides a useful framework for evaluating the mountain research community\u27s progress toward addressing global change and sustainability challenges. Using a process originally set up to analyze contributions to the 2010 conference, the abstracts accepted for the 2015 conference in the context of the Future Earth framework were analyzed. This revealed a continued geographic underrepresentation in mountain research of Africa, Latin America, and South and Southeast Asia but a more even treatment of biophysical and social science themes than in 2010. It also showed that the Perth conference research community strongly focused on understanding system processes (the Dynamic Planet theme of the Future Earth research agenda). Despite the continued bias of conference contributions toward traditional observation- and conservation-oriented research, survey results indicate that conference participants clearly believe that transdisciplinary, transformative research is relevant to mountains. Of the 8 Future Earth focal challenges, those related to safeguarding natural assets, promoting sustainable land use, increasing resilience and understanding the water-energy-food nexus received considerable attention. The challenges related to sustainable consumption, decarbonizing socioeconomic systems, cities, and health were considerably less well represented, despite their relevance to mountain socioeconomic systems. Based on these findings, we outline a proposal for the future directions of mountain research

Stressful events and individual beliefs as correlates of economic disadvantage and aggression among urban children.

This study examined 3 factors that were hypothesized to increase risk for aggression among urban children: economic disadvantage, stressful events, and individual beliefs. Participants were 1,935 African American, Hispanic, and White elementary-school boys and girls assessed over a 2-year period. The relation between individual poverty and aggression was only significant for the White children, with significant interactions between individual and community poverty for the other 2 ethnic groups. With a linear structural model to predict aggression from the stress and beliefs variables, individual poverty predicted stress for African American children and predicted beliefs supporting aggression for Hispanic children. For all ethnic groups, both stress and beliefs contributed significantly to the synchronous prediction of aggression, and for the Hispanic children, the longitudinal predictions were also significant. The findings are discussed in terms of their implications for preventive interventions in multiethnic, inner-city communities.The research was supported by Grant MH-48034 from the National Institute of Mental Health and Cooperative Agreement CCU510017 from the Centers for Disease Control and Prevention.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83500/1/1995.Guerra_etal.StressfulEvents&IndiBeliefsasCorrelatesofEconDisadvantage&AggAmongUrbChildrn.JourofCnsulting&ClinPsych.pd

Normative Influences on Aggression in Urban Elementary School Classrooms

We report a study aimed at understanding the effects of classroom normative influences on individual aggressive behavior, using samples of 614 and 427 urban elementary school children. Participants were assessed with measures of aggressive behavior and normative beliefs about aggression. We tested hypotheses related to the effects of personal normative beliefs, descriptive classroom norms (the central tendency of classmates' aggressive behavior), injunctive classroom normative beliefs (classmates' beliefs about the acceptability of aggression), and norm salience (student and teacher sanctions against aggression) on longitudinal changes in aggressive behavior and beliefs. Injunctive norms affected individual normative beliefs and aggression, but descriptive norms had no effect on either. In classrooms where students and teachers made norms against aggression salient, aggressive behavior diminished over time. Implications for classroom behavior management and further research are discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44053/1/10464_2004_Article_223769.pd

Non-Invasive Brain Computer Interface for Mental Control of a Simulated Wheelchair

This poster presents results obtained from experiments of driving a brain-actuated simulated wheelchair that incorporates the shared-control intelligence method. The simulated wheelchair is controlled offline using band power features. The task is to drive the wheelchair along a corridor avoiding two obstacles. We have analyzed data from 4 na�ve subjects during 25 sessions carried out in two days. To measure the performance of the brain-actuated wheelchair we have compared the final position of the wheelchair with the end point of the desired trajectory. The experiments show that the incorporation of a higher intelligence level in the control device significantly helps the subject to drive the robot device

Subcellular compartmentation of glutathione in dicotyledonous plants

This study describes the subcellular distribution of glutathione in roots and leaves of different plant species (Arabidopsis, Cucurbita, and Nicotiana). Glutathione is an important antioxidant and redox buffer which is involved in many metabolic processes including plant defense. Thus information on the subcellular distribution in these model plants especially during stress situations provides a deeper insight into compartment specific defense reactions and reflects the occurrence of compartment specific oxidative stress. With immunogold cytochemistry and computer-supported transmission electron microscopy glutathione could be localized in highest contents in mitochondria, followed by nuclei, peroxisomes, the cytosol, and plastids. Within chloroplasts and mitochondria, glutathione was restricted to the stroma and matrix, respectively, and did not occur in the lumen of cristae and thylakoids. Glutathione was also found at the membrane and in the lumen of the endoplasmic reticulum. It was also associated with the trans and cis side of dictyosomes. None or only very little glutathione was detected in vacuoles and the apoplast of mesophyll and root cells. Additionally, glutathione was found in all cell compartments of phloem vessels, vascular parenchyma cells (including vacuoles) but was absent in xylem vessels. The specificity of this method was supported by the reduction of glutathione labeling in all cell compartments (up to 98%) of the glutathione-deficient Arabidopsis thaliana rml1 mutant. Additionally, we found a similar distribution of glutathione in samples after conventional fixation and rapid microwave-supported fixation. Thus, indicating that a redistribution of glutathione does not occur during sample preparation. Summing up, this study gives a detailed insight into the subcellular distribution of glutathione in plants and presents solid evidence for the accuracy and specificity of the applied method

Gene expression profiling and silencing reveal that monolignol biosynthesis plays a critical role in penetration defence in wheat against powdery mildew invasion

Cell wall apposition (CWA) formation is one of the first lines of defence used by plants to halt invading fungi such as powdery mildew. Lignin is a complex polymer of hydroxylated and methoxylated phenylpropane units (monolignols) and lignification renders the cell wall more resistant to pathogen attack. The role of monolignol biosynthesis in CWA-mediated defence against powdery mildew penetration into cereals is demonstrated here using RNA interference (RNAi)-mediated gene silencing and enzyme-specific inhibitors. Thirteen cDNAs representing eight genes involved in monolignol biosynthesis were cloned from an expression sequence tag (EST) library derived from the epidermis of diploid wheat (Triticum monococcum) infected with Blumeria graminis f. sp. tritici (Bgt). Differential expression patterns were found for these genes in susceptible and resistant plants after infection. Transcripts of phenylalanine ammonia lyase (PAL), caffeic acid O-methyltransferase (CAOMT), ferulic acid hydroxylase (FAH), caffeoyl-CoA O-methyltransferase (CCoAMT), and cinnamyl alcohol dehydrogenase (CAD) were accumulated, particularly in the epidermis. RNAi-mediated transient gene silencing in the epidermis led to a higher penetration efficiency of Bgt than in the controls. Gene silencing also compromised penetration resistance to varying degrees with different genes against an inappropriate pathogen, B. graminis f. sp. hordei (Bgh). Co-silencing led to greater penetration of Bgt or Bgh than when the genes were silenced separately. Fluorescence emission spectra analyses revealed that gene silencing hampered host autofluorescence response at fungal contact sites. These results illustrate that monolignol biosynthesis is critically important for host defence against both appropriate and inappropriate pathogen invasion in wheat

A Brain-Actuated Wheelchair: Asynchronous and Non-Invasive Brain-Computer Interfaces for Continuous Control of Robots

Objective: To assess the feasibility and robustness of an asynchronous and non-invasive EEG-based Brain-Computer Interface (BCI) for continuous mental control of a wheelchair. Methods: In experiment 1 two subjects were asked to mentally drive both a real and a simulated wheelchair from a starting point to a goal along a pre-specified path. Here we only report experiments with the simulated wheelchair for which we have extensive data in a complex environment that allows a sound analysis. Each subject participated in 5 experimental sessions, each consisting of 10 trials. The time elapsed between two consecutive experimental sessions was variable (from one hour to two months) to assess the system robustness over time. The pre-specified path was divided in 7 stretches to assess the system robustness in different contexts. To further assess the performance of the brain-actuated wheelchair, subject 1 participated in a second experiment consisting of 10 trials where he was asked to drive the simulated wheelchair following 10 different complex and random paths never tried before. Results: In experiment 1 the two subjects were able to reach 100% (subject 1) and 80% (subject 2) of the final goals along the pre-specified trajectory in their best sessions. Different performances were obtained over time and path stretches, what indicates that performance is time and context dependent. In experiment 2, subject 1 was able to reach the final goal in 80% of the trials. Conclusions: The results show that subjects can rapidly master our asynchronous EEG-based BCI to control a wheelchair. Also, they can autonomously operate the BCI over long periods of time without the need for adaptive algorithms externally tuned by a human operator to minimize the impact of EEG non-stationarities. This is possible because of two key components: first, the inclusion of a shared control system between the BCI system and the intelligent simulated wheelchair; second, the selection of stable user-specific EEG features that maximize the separability between the mental tasks. Significance: These results show the feasibility of continuously controlling complex robotics devices using an asynchronous and non-invasive BCI

Adaptive Shared Control of a Brain-Actuated Simulated Wheelchair

The use of shared control techniques has a profound impact on the performance of a robotic assistant controlled by human brain signals. However, this shared control usually provides assistance to the user in a constant and identical manner each time. Creating an adaptive level of assistance, thereby complementing the user's capabilities at any moment, would be more appropriate. The better the user can do by himself, the less assistance he receives from the shared control system; and vice versa. In order to do this, we need to be able to detect when and in what way the user needs assistance. An appropriate assisting behaviour would then be activated for the time the user requires help, thereby adapting the level of assistance to the specific situation. This paper presents such a system, helping a brain-computer interface (BCI) subject perform goal-directed navigation of a simulated wheelchair in an adaptive manner. Whenever the subject has more difficulties in driving the wheelchair, more assistance will be given. Experimental results of two subjects show that this adaptive shared control increases the task performance. Also, it shows that a subject with a lower BCI performance has more need for extra assistance in difficult situations, such as manoeuvring in a narrow corridor