The separate neural control of hand movements and contact forces

To manipulate an object, we must simultaneously control the contact forces exerted on the object and the movements of our hand. Two alternative views for manipulation have been proposed: one in which motions and contact forces are represented and controlled by separate neural processes, and one in which motions and forces are controlled jointly, by a single process. To evaluate these alternatives, we designed three tasks in which subjects maintained a specified contact force while their hand was moved by a robotic manipulandum. The prescribed contact force and hand motions were selected in each task to induce the subject to attain one of three goals: (1) exerting a regulated contact force, (2) tracking the motion of the manipulandum, and (3) attaining both force and motion goals concurrently. By comparing subjects' performances in these three tasks, we found that behavior was captured by the summed actions of two independent control systems: one applying the desired force, and the other guiding the hand along the predicted path of the manipulandum. Furthermore, the application of transcranial magnetic stimulation impulses to the posterior parietal cortex selectively disrupted the control of motion but did not affect the regulation of static contact force. Together, these findings are consistent with the view that manipulation of objects is performed by independent brain control of hand motions and interaction forces

Learning Redundant Motor Tasks With and Without Overlapping Dimensions: Facilitation and Interference Effects

Prior learning of a motor skill creates motor memories that can facilitate or interfere with learning of new, but related, motor skills. One hypothesis of motor learning posits that for a sensorimotor task with redundant degrees of freedom, the nervous system learns the geometric structure of the task and improves performance by selectively operating within that task space. We tested this hypothesis by examining if transfer of learning between two tasks depends on shared dimensionality between their respective task spaces. Human participants wore a data glove and learned to manipulate a computer cursor by moving their fingers. Separate groups of participants learned two tasks: a prior task that was unique to each group and a criterion task that was common to all groups. We manipulated the mapping between finger motions and cursor positions in the prior task to define task spaces that either shared or did not share the task space dimensions (x-y axes) of the criterion task. We found that if the prior task shared task dimensions with the criterion task, there was an initial facilitation in criterion task performance. However, if the prior task did not share task dimensions with the criterion task, there was prolonged interference in learning the criterion task due to participants finding inefficient task solutions. These results show that the nervous system learns the task space through practice, and that the degree of shared task space dimensionality influences the extent to which prior experience transfers to subsequent learning of related motor skills

A review on the use of Information Communication Technology (ICT) in fisheries management: A case of Mbenji Island small-scale fishery in Malawi

Fisheries management has evolved in Malawi from a traditional system to a centralized regime and lately to co-management fisheries systems, although, success stories about sustainability of the fishery resources are few. Open access nature of fisheries resources has posed a challenge to management regimes. Resource overexploitation has continued in a majority of fisheries worsened by large stretches of the shoreline manned by a single fisheries field staff, and limited capacity by DoF to monitor and manage the fishery. However, isolated localities have upheld management styles that have facilitated sustainable exploitation. Mbenji Island fishery ‘managers’ have ensured high compliance to fisheries rules and regulations among fishers through strict enforcement and maintained abundant fish stocks amid visibly declining levels of fish in vast localities of Lake Malawi and other water bodies in Malawi. There is, therefore, need to take the Mbenji Island success story to other fishing communities to learn from their fisheries management strategies. Information Communication Technology (ICT) as a powerful means in mobilizing communities to take charge of their own development should support ‘best practices’ and offer fishing communities access to the same type of services and advantages. If appropriately applied, ICT can provide for real-time monitoring of fisheries resources as fishers alarm law enforcers to move in at appropriate times. Fishers also strike deals on mobile phones for the day's catch even before landing at shore. This reduces post-harvest waste from delayed handling of fish. Computers have been used for data management, storage and analysis as well as accessing internet services. Studies have shown commonalities in fisher communities in terms of socio-economic and cultural characteristics. On the basis of such an advantage, more could be shared among such communities. Management success can be adopted by other communities of fishers through use of ICT such as radio programs (supplemented by phone-in sessions) undertaken by local-level resource users. These programs provide locally available information and knowledge on best practices aimed at sustainability with means within communities. This encourages community members in other localities to come together to seek the way forward on the basis of lessons from successful communities aired on local radio stations (both community or national radio stations). It is easier to adopt practices that have worked in near vicinities. After all, what is currently called comanagement is seemingly based on indigenous knowledge of fishers and other resource users. Mbenji Island is one of the custodians of ICT option in small-scale fisheries management of Lake Malawi. Information Communication Technology provides opportunity for both the Malawi Department of Fisheries (DoF) and fishers with information about fisher community activities including catch and market regardless of distance.&nbsp

Exploring Carrier Sense Multiple Access with Collision Avoidance Techniques for Resource Sharing in Broadband Power Line Communications

A resource sharing in power line communications (PLC) for the home network is restricted by the channel assignment techniques which decide who has the right to gain access to send data. The channel assignment techniques include contention-free and contention-based. The former requires high synchronization due to the deterministic round-trip time. Besides, contention-based utilizes CSMA/CA techniques that allow stations in a network to compete for channel access and are suitable for decentralized network topology. However, a trade-off exists between the number of stations required to gain access versus system efficiency. Whilst some research has been carried out on CSMA/CA resource sharing techniques that allow only one user to transmit, there is very little work done on multiuser access to optimize system efficiency and reduce collisions in a network. The purpose of the current study was to review the CSMA/CA techniques for resource sharing to improve system efficiency in power line communications. In carrying out this study, a systematic literature review methodology to evaluate different related works and determine the most suitable approach to allow multiuser channel access was used. The study further demonstrated the impact multichannel access has on system efficiency. In addition, the study provides recommendations for future research. Keywords: CSMA/CA; Medium access control; OFDMA; power line; resource sharing

SGLT2 Inhibitors Therapy in Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a chronic progressive disease characterized by chronic hyperglycemia and increased risk of cardiovascular disease (CVD). It results from multiple defects that lead to defective regulation of the blood glucose and requires continuous medical care with multifactorial risk-reduction strategies beyond glycemic control. Multiple groups of drugs have been approved in the past decades that work through different mechanisms. Apart from their limited efficacy in reducing cardiovascular outcome, most of them are neutral, and some may even increase mortality from CVDs such as rosiglitazone. The kidney has an important role in glucose regulation that was only recently targeted for drug development. Sodium-glucose cotransporter 2 inhibitors (SGLT2-I) are a new class of oral antihyperglycemic (OAH) agents that mainly act by preventing the reabsorption of filtered glucose by renal convoluted tubules. By their insulin-independent unique mechanism of action, SGLT2-I result in treating hyperglycemia while avoiding hypoglycemia, promote weight loss, reduce blood pressure, and, more importantly, decrease the risk of major adverse cardiovascular events (MACE). Therefore, SGLT2-I address fundamental aspects of the unmet needs of T2DM management that most of the other OAH failed to resolve. The main side effects of SGLT2-I are slight increase in the incidence of genital mycotic infections (GMI) and euglycemic ketoacidosis (EKA) along with increased risk of lower limb amputations, which has been reported with some but not all agents of this class