Implications Of Co-occurrence Research Articles

Importance of Srepok Wildlife Sanctuary, Cambodia, for the endangered green peafowl: implications of co-occurrence near human use areas

Importance of Srepok Wildlife Sanctuary, Cambodia, for the endangered green peafowl: implications of co-occurrence near human use areas

Simulated muscle activity in locomotion: implications of co-occurrence between effort minimisation and gait modularity for robot-assisted rehabilitation therapy

Evolution of gait rehabilitation robotic devices for stroke survivors has aimed at providing transparency to user’s efforts and implementing ‘assist-as-needed’ paradigm. Alteration of muscle activity and synergies recruitment has been noticed in trials involving healthy subjects but no analytic tool has been proposed to understand root causes. In this paper, a simplified neuro-mechanical model is introduced for simulating lower limbs’ muscle activity during unrestrained and device-constrained gait, taking into consideration exoskeleton-plus-treadmill and end-effector categories. Muscle control is based on the key hypothesis that optimality criterion pursues co-occurrence between effort minimisation and modularity during regular gait. Results highlight that modelised motion constraints on lower body raise additional redundancies which alter muscle activity and increase intervention external to unrestrained gait synergies. Accordingly, the developed simulations help to identify the inherent limitations of current technology: further degree of freedom addition to exoskeleton-plus-treadmill device could be useful but impractical, while end-effector devices would benefit significantly from an improved interaction management.

Factors shaping the co-occurrence of two juvenile shark species along the Texas Gulf Coast

As top predators, sharks play important ecological roles in coastal marine ecosystems. Yet, environmental changes in many coastal regions are likely altering the composition of ecological communities, the interspecific interactions sharks have within coastal waters, and subsequently the ecological roles sharks play within these ecosystems. As such, understanding interactions among sharks, and how extrinsic factors shape these interactions, is important for predicting the consequences of future human impacts and environmental changes. Elucidating the contexts under which species co-occur and the implications of co-occurrence is an important step in developing such a predictive framework. Blacktip shark (Carcharhinus limbatus) and bull shark (Carcharhinus leucas) concentrations were quantified using long-term coastal gill net survey data across five bay systems in Texas. Relationships between co-occurrence, and environmental factors and shark sizes were examined within and across species. Co-occurrence of blacktip sharks and bull sharks varied spatially and temporally, with a significant increase in interspecific co-occurrence from the 1970s to 2010s, and a significant decrease in bull shark concentrations through time. Changes in environmental conditions, specifically increasing salinities, may have been responsible for increased blacktip and bull shark co-occurrence, and potential interspecific competition, which in turn may have led to decreased bull shark concentrations to reduce intraspecific competition. However, more refined questions are needed before predictive frameworks can be developed concerning the contexts under which co-occurrence is prevalent. Quantifying resource use among coastal sharks will help elucidate the drivers and implications of co-occurrence, and the potential for competitive interactions within and across species.