Ecogeomorphic coevolution of semiarid hillslopes: Emergence of banded and striped vegetation patterns through interaction of biotic and abiotic processes

[1] Nonlinear interactions between physical and biological factors give rise to the emergence of remarkable landform‐vegetation patterns. Patterns of vegetation and resource redistribution are linked to productivity and carrying capacity of the land. As a consequence, growing concern over ecosystem resilience to perturbations that could lead to irreversible land degradation imposes a pressing need for understanding the processes, nonlinear interactions, and feedbacks, leading to the coevolution of these patterns. For arid and semiarid regions, causes for concern have increased at a rapid pace during the last few decades due to growing anthropic and climatic pressures that have resulted in the degradation of numerous areas worldwide. This paper aims at improving our understanding of the ecogeomorphic evolution of landscape patterns in semiarid areas with a sparse biomass cover through a modeling approach. A coupled vegetation‐pattern formation and landform evolution model is used to study the coevolution of vegetation and topography over centennial timescales. Results show that self‐organized vegetation patterns strongly depend on feedbacks with coevolving landforms. The resulting patterns depend on the erosion rate and mechanism (dominance of either fluvial or diffusive processes), which are affected by biotic factors. Moreover, results show that ecohydrologic processes leading to banded pattern formation, when coupled with landform processes, can also lead to completely different patterns (stripes of vegetation along drainage lines) that are equally common in semiarid areas. These findings reinforce the importance of analyzing the coevolution of landforms and vegetation to improve our understanding of the patterns and structures found in nature

Impaired neural processing of dynamic faces in left-onset Parkinson's disease

Parkinson's disease (PD) affects patients beyond the motor domain. According to previous evidence, one mechanism that may be impaired in the disease is face processing. However, few studies have investigated this process at the neural level in PD. Moreover, research using dynamic facial displays rather than static pictures is scarce, but highly warranted due to the higher ecological validity of dynamic stimuli. In the present study we aimed to investigate how PD patients process emotional and non-emotional dynamic face stimuli at the neural level using event-related potentials. Since the literature has revealed a predominantly right-lateralized network for dynamic face processing, we divided the group into patients with left (LPD) and right (RPD) motor symptom onset (right versus left cerebral hemisphere predominantly affected, respectively). Participants watched short video clips of happy, angry, and neutral expressions and engaged in a shallow gender decision task in order to avoid confounds of task difficulty in the data. In line with our expectations, the LPD group showed significant face processing deficits compared to controls. While there were no group differences in early, sensory-driven processing (fronto-central N1 and posterior P1), the vertex positive potential, which is considered the fronto-central counterpart of the face-specific posterior N170 component, had a reduced amplitude and delayed latency in the LPD group. This may indicate disturbances of structural face processing in LPD. Furthermore, the effect was independent of the emotional content of the videos. In contrast, static facial identity recognition performance in LPD was not significantly different from controls, and comprehensive testing of cognitive functions did not reveal any deficits in this group. We therefore conclude that PD, and more specifically the predominant right-hemispheric affection in left-onset PD, is associated with impaired processing of dynamic facial expressions, which could be one of the mechanisms behind the often reported problems of PD patients in their social lives

Contribution of brain or biological reserve and cognitive or neural reserve to outcome after TBI: a meta-analysis (prior to 2015)

Brain/biological (BR) and cognitive/neural reserve (CR) have increasingly been used to explain some of the variability that occurs as a consequence of normal ageing and neurological injuries or disease. However, research evaluating the impact of reserve on outcomes after adult traumatic brain injury (TBI) has yet to be quantitatively reviewed. This meta-analysis consolidated data from 90 studies (published prior to 2015) that either examined the relationship between measures of BR (genetics, age, sex) or CR (education, premorbid IQ) and outcomes after TBI or compared the outcomes of groups with high and low reserve. The evidence for genetic sources of reserve was limited and often contrary to prediction. APOE ∈4 status has been studied most, but did not have a consistent or sizeable impact on outcomes. The majority of studies found that younger age was associated with better outcomes, however most failed to adjust for normal age-related changes in cognitive performance that are independent of a TBI. This finding was reversed (older adults had better outcomes) in the small number of studies that provided age-adjusted scores; although it remains unclear whether differences in the cause and severity of injuries that are sustained by younger and older adults contributed to this finding. Despite being more likely to sustain a TBI, males have comparable outcomes to females. Overall, as is the case in the general population, higher levels of education and pre-morbid IQ are both associated with better outcomes.Jane L. Mathias, Patricia Wheato

Models of classroom assessment for course-based research experiences

Course-based research pedagogy involves positioning students as contributors to authentic research projects as part of an engaging educational experience that promotes their learning and persistence in science. To develop a model for assessing and grading students engaged in this type of learning experience, the assessment aims and practices of a community of experienced course-based research instructors were collected and analyzed. This approach defines four aims of course-based research assessment—(1) Assessing Laboratory Work and Scientific Thinking; (2) Evaluating Mastery of Concepts, Quantitative Thinking and Skills; (3) Appraising Forms of Scientific Communication; and (4) Metacognition of Learning—along with a set of practices for each aim. These aims and practices of assessment were then integrated with previously developed models of course-based research instruction to reveal an assessment program in which instructors provide extensive feedback to support productive student engagement in research while grading those aspects of research that are necessary for the student to succeed. Assessment conducted in this way delicately balances the need to facilitate students’ ongoing research with the requirement of a final grade without undercutting the important aims of a CRE education

The impact of pharmacological treatments on outcome after adult traumatic brain injury: what does the research show?

A traumatic brain injury (TBI) can cause immediate and delayed damage to the brain producing long-term cognitive and behavioural problems. Young people in the early stages of a productive life are at most risk of sustaining a TBI making these persistent problems of major personal and social importance. Post-TBI rehabilitation provides one possible strategy for improving outcome following injury. Pharmacological treatments, on the other hand, have the potential to either minimise the amount of damage that the brain sustains following TBI, thereby improving outcome, or reduce persistent biochemical disruptions that are associated with poorer outcome. However, research in this area has shown mixed results hampering advances in the treatment of this condition. This thesis will, therefore, synthesise the findings from pre-clinical and clinical research that has examined the effects of pharmacological treatments on cognitive and behavioural outcome following adult TBI. A large number of the pharmacological agents have been investigated in pre-clinical experimental research with rodents making it difficult to consolidate the findings. Therefore, the first study meta-analysed the data from 223 pre-clinical studies that examined 91 pharmacological treatments in adult male rodents (rats, mice) after TBI. Sixteen treatments improved cognition and motor outcome across a range of models of TBI injury. Four of these showed dose-dependent treatment effects and two showed treatment-interval effects. The findings suggest that anti-inflammatories are the most efficacious treatments for improving cognition and motor function in rodents following TBI. Behaviour, on the other hand, did not improve with any of the treatments. It is unclear whether these treatment benefits translate to an adult human TBI population. Study two, therefore, evaluated the impact of early (≤ 7 days post-injury) pharmacological treatments on cognition and behaviour in humans after TBI using meta-analytic techniques. Twenty-two studies that investigated eleven different treatments were analysed. Two treatments (amantadine and bradycor) showed marked improvements in arousal. A further three were associated with dose-dependent treatment effects (LF 16-0687Ms, dexanabinol, GK-11). The out-come measure used to evaluate a pharmacological agent influenced the likelihood of finding a treatment benefit. It is also unclear whether long-term changes (≥ 4 weeks post-injury) to neurotransmitters in the brain additionally benefit from pharmacological interventions. Again, the findings from clinical studies in an adult human TBI population have been inconsistent. In study three, the data from 30 studies that investigated 19 pharmacological treatments administered prior to and spanning, the post-acute stage, and in the post-acute stage after adult human TBI were synthesised. Three treatments (methylphenidate, amantadine, donepezil) improved behaviour (mood, combativeness), cognition or general outcome while one (sertraline) worsened post-concussion symptoms and cognition. In summary, this thesis confirms that both early and post-acute pharmacological interventions can improve the outcomes of adult rodents and humans after TBI. Early treatments that reduce brain swelling (i.e., inflammation and oedema) appear to be beneficial to outcome in both rodents and humans. Stimulant treatments administered to humans in the early and post-acute stage after TBI also show marked benefits. Finally, drug dosage, injury-to-treatment interval and outcome measure influenced the likelihood of finding treatment benefits.Thesis (Ph.D.) -- University of Adelaide, School of Psychology, 201

Zinc and vitamin A supplementation in Indigenous Australian children hospitalised with lower respiratory tract infection: a randomised controlled trial

Objective: To evaluate the efficacy of supplementation with zinc and vitamin A in Indigenous children hospitalised with acute lower respiratory infection (ALRI). Design: Randomised controlled, 2-by-2 factorial trial of supplementation with zinc and vitamin A. Setting and participants: 187 Indigenous children aged < 11 years hospitalised with 215 ALRI episodes at Alice Springs Hospital (April 2001 to July 2002). Interventions: Vitamin A was administered on Days 1 and 5 of admission at a dose of 50 000 IU (infants under 12 months), or 100 000 IU; and zinc sulfate was administered daily for 5 days at a daily dose of 20 mg (infants under 12 months) or 40 mg. Main outcome measure: Time to clinical recovery from fever and tachypnoea, duration of hospitalisation, and readmission for ALRI within 120 days. Results: There was no clinical benefit of supplementation with vitamin A, zinc or the two combined, with no significant difference between zinc and no-zinc, vitamin A and no-vitamin A or zinc + vitamin A and placebo groups in time to resolution of fever or tachypnoea, or duration of hospitalisation. Instead, we found increased morbidity; children given zinc had increased risk of readmission for ALRI within 120 days (relative risk, 2.4; 95% CI, 1.003–6.1). Conclusion: This study does not support the use of vitamin A or zinc supplementation in the management of ALRI requiring hospitalisation in Indigenous children living in remote areas. Even in populations with high rates of ALRI and poor living conditions, vitamin A and zinc therapy may not be useful. The effect of supplementation may depend on the prevalence of deficiency of these micronutrients in the population

Zinc and vitamin A supplementation in Australian indigenous children with acute diarrhoea: a randomised controlled trial

Objective: To evaluate the role of zinc and vitamin A supplementation in the recovery of Indigenous children hospitalised for acute diarrhoea.Design: A randomised controlled 2 by 2 factorial trial of supplementation with zinc and vitamin A.Setting and participants: Aboriginal children (aged &lt; 11 years) hospitalised for acute diarrhoea at Alice Springs Hospital, Northern Territory, April 2001&ndash;July 2002.Main outcome measures: Duration of diarrhoeal illness; re-admission for diarrhoeal illness within 120 days.Results: Our study involved 392 Aboriginal children with 436 episodes of diarrhoea. Supplementation with zinc, vitamin A, or combined zinc and vitamin A had no significant effect on duration of diarrhoea or rate of re-admission compared with placebo. Median diarrhoea duration after starting supplementation was 3.0 days for the vitamin A and zinc supplemented and placebo groups (P values 0.25 and 0.69, respectively). The number of re-admissions did not differ significantly between those receiving vitamin A or zinc and the relevant placebo groups (relative risk [95% CI], 1.2 [0.7&ndash;2.1] and 1.3 [0.8&ndash;2.1], respectively).Conclusion: Vitamin A and zinc supplementation may not be indicated for in-hospital management of acute diarrhoeal disease in Aboriginal children living in remote areas. This finding may not apply to children with malnutrition, for whom other studies suggest a benefit. Larger trials incorporating more comprehensive data on the vitamin A and zinc status as well as nutritional status of study populations might help to explain the different results in different populations