Maize varietal replacement in Eastern and Southern Africa: Bottlenecks, drivers and strategies for improvement.

Seed security is vital for food security. Rapid-cycle, climate-adaptive breeding programs and seed systems that deliver new, elite varieties to farmers to replace obsolete ones can greatly improve the productivity of maize-based cropping systems in sub-Saharan Africa (SSA). Despite the importance and benefits of accelerated varietal turnover to climate change adaptation and food security, the rate of maize varietal replacement in SSA is slow. This review outlines the major bottlenecks, drivers, risks, and benefits of active replacement of maize varieties in eastern and southern Africa (ESA) and highlights strategies that are critical to varietal turnover. Although there is an upsurge of new seed companies in ESA and introduction of new varieties with better genetics in the market, some established seed companies continue to sell old (over 15-year-old) varieties. Several recently developed maize hybrids in ESA have shown significant genetic gains under farmers' conditions. Empirical evidence also shows that timely replacement of old products results in better business success as it helps seed companies maintain or improve market share and brand relevance. Therefore, proactive management of product life cycles by seed companies benefits both the farmers and businesses alike, contributing to improved food security and adaptation to the changing climate.

Redefining the Trauma Triage Matrix: The Role of Emergent Interventions.

BACKGROUND: A tiered trauma team activation (TTA) system aims to allocate resources proportional to the patient's need based upon injury burden. The current metrics used to evaluate appropriateness of TTA are the trauma triage matrix (TTM), need for trauma intervention (NFTI), and secondary triage assessment tool (STAT). MATERIALS AND METHODS: In this retrospective study, we compared the effectiveness of the need for an emergent intervention within 6 h (NEI-6) with existing definitions. Data from the Michigan Trauma Quality Improvement Program was utilized. The dataset contains information from 31 level 1 and 2 trauma centers from 2011 to 2017. Inclusion criteria were: adult patients (≥16 y) and ISS ≥5. RESULTS: 73,818 patients were included in the study. Thirty percentage of trauma patients met criteria for STAT, 21% for NFTI, 20% for TTM, and 13% for NEI-6. NEI-6 was associated with the lowest rate of undertriage at 6.5% (STAT 22.3%, NFTI 14.0%, TTM 14.3%). NEI-6 best predicted undertriage mortality, early mortality, in-hospital mortality, and late (>60 h) mortality. Most patients who met criteria for TTM (58%), NFTI (51%), and STAT (62%) did not require emergent intervention. All four methods had similar rates of early mortality for patients who did not meet criteria (0.3%-0.5%). CONCLUSIONS: NEI-6 performs better than TTM, NFTI, and STAT in terms of undertriage, mortality and need for resource utilization. Other methods resulted in significantly more full TTAs than NEI-6 without identifying patients at risk for early mortality. NEI-6 represents a novel tool to determine trauma activation appropriateness.

Cerebellar Transcranial Direct Current Stimulation (ctDCS): A Novel Approach to Understanding Cerebellar Function in Health and Disease.

The cerebellum is critical for both motor and cognitive control. Dysfunction of the cerebellum is a component of multiple neurological disorders. In recent years, interventions have been developed that aim to excite or inhibit the activity and function of the human cerebellum. Transcranial direct current stimulation of the cerebellum (ctDCS) promises to be a powerful tool for the modulation of cerebellar excitability. This technique has gained popularity in recent years as it can be used to investigate human cerebellar function, is easily delivered, is well tolerated, and has not shown serious adverse effects. Importantly, the ability of ctDCS to modify behavior makes it an interesting approach with a potential therapeutic role for neurological patients. Through both electrical and non-electrical effects (vascular, metabolic) ctDCS is thought to modify the activity of the cerebellum and alter the output from cerebellar nuclei. Physiological studies have shown a polarity-specific effect on the modulation of cerebellar-motor cortex connectivity, likely via cerebellar-thalamocortical pathways. Modeling studies that have assessed commonly used electrode montages have shown that the ctDCS-generated electric field reaches the human cerebellum with little diffusion to neighboring structures. The posterior and inferior parts of the cerebellum (i.e., lobules VI-VIII) seem particularly susceptible to modulation by ctDCS. Numerous studies have shown to date that ctDCS can modulate motor learning, and affect cognitive and emotional processes. Importantly, this intervention has a good safety profile; similar to when applied over cerebral areas. Thus, investigations have begun exploring ctDCS as a viable intervention for patients with neurological conditions.

The salience network is responsible for switching between the default mode network and the central executive network: replication from DCM.

With the advent of new analysis methods in neuroimaging that involve independent component analysis (ICA) and dynamic causal modelling (DCM), investigations have focused on measuring both the activity and connectivity of specific brain networks. In this study we combined DCM with spatial ICA to investigate network switching in the brain. Using time courses determined by ICA in our dynamic causal models, we focused on the dynamics of switching between the default mode network (DMN), the network which is active when the brain is not engaging in a specific task, and the central executive network (CEN), which is active when the brain is engaging in a task requiring attention. Previous work using Granger causality methods has shown that regions of the brain which respond to the degree of subjective salience of a stimulus, the salience network, are responsible for switching between the DMN and the CEN (Sridharan et al., 2008). In this work we apply DCM to ICA time courses representing these networks in resting state data. In order to test the repeatability of our work we applied this to two independent datasets. This work confirms that the salience network drives the switching between default mode and central executive networks and that our novel technique is repeatable.