Asymmetric interlimb transfer of concurrent adaptation to opposing dynamic forces

Interlimb transfer of a novel dynamic force has been well documented. It has also been shown that unimanual adaptation to opposing novel environments is possible if they are associated with different workspaces. The main aim of this study was to test if adaptation to opposing velocity dependent viscous forces with one arm could improve the initial performance of the other arm. The study also examined whether this interlimb transfer occurred across an extrinsic, spatial, coordinative system or an intrinsic, joint based, coordinative system. Subjects initially adapted to opposing viscous forces separated by target location. Our measure of performance was the correlation between the speed profiles of each movement within a force condition and an ‘average’ trajectory within null force conditions. Adaptation to the opposing forces was seen during initial acquisition with a significantly improved coefficient in epoch eight compared to epoch one. We then tested interlimb transfer from the dominant to non-dominant arm (D → ND) and vice-versa (ND → D) across either an extrinsic or intrinsic coordinative system. Interlimb transfer was only seen from the dominant to the non-dominant limb across an intrinsic coordinative system. These results support previous studies involving adaptation to a single dynamic force but also indicate that interlimb transfer of multiple opposing states is possible. This suggests that the information available at the level of representation allowing interlimb transfer can be more intricate than a general movement goal or a single perceived directional error

Concurrent adaptation to opposing visual displacements during an alternating movement.

It has been suggested that, during tasks in which subjects are exposed to a visual rotation of cursor feedback, alternating bimanual adaptation to opposing rotations is as rapid as unimanual adaptation to a single rotation (Bock et al. in Exp Brain Res 162:513–519, 2005). However, that experiment did not test strict alternation of the limbs but short alternate blocks of trials. We have therefore tested adaptation under alternate left/right hand movement with opposing rotations. It was clear that the left and right hand, within the alternating conditions, learnt to adapt to the opposing displacements at a similar rate suggesting that two adaptive states were formed concurrently. We suggest that the separate limbs are used as contextual cues to switch between the relevant adaptive states. However, we found that during online correction the alternating conditions had a significantly slower rate of adaptation in comparison to the unimanual conditions. Control conditions indicate that the results are not directly due the alternation between limbs or to the constant switching of vision between the two eyes. The negative interference may originate from the requirement to dissociate the visual information of these two alternating displacements to allow online control of the two arms

Sub-movement organisation, pen pressure and muscle activity are modulated to precision demands in 2D tracking

The authors investigated how tracking performance, submovement organization, pen pressure and muscle activity in forearm and shoulder muscles were affected by target size in a 2D tracking task performed with a pen on a digitizer tablet. Twenty-six subjects took part in an experiment, in which either a small dot or a large dot was tracked, while it moved quasirandomly across a computer screen at a constant velocity of 2cm/s. The manipulation of precision level was successful, because mean distance to target and the standard deviation of this distance were significantly smaller with the small target than with the large target. With a small target, subjects trailed more behind the center of target and used submovements with larger amplitudes and of shorter duration, resulting in higher tracking accuracy. This change in submovement organization was accompanied by higher pen pressure, while at the same time muscle activity in the forearm extensors and flexors was increased, indicating higher endpoint stability. In conclusion, increased precision demands were accommodated by both a different organization of submovements and higher endpoint stability in a 2D tracking task performed with a pen on a digitizer tablet. © 2012 Copyright Taylor and Francis Group, LLC

Agricultural Co-Operatives and Training of Male and Female Farmers on Improved Rice (Oryza sativa) Production Techniques in Ini Local Government Area, Akwa Ibom State, Nigeria

This study assessed the extent to which agricultural cooperatives carryout the training of male and female farmers on improved rice (Oryza sativa) production techniques in Ini Local Government Area of Akwa Ibom state, Nigeria using research questions for 2,500 (male and female) rice farmer cooperative members in the study Area. Data analysis for 1600 completed questionnaire collected revealed that male and female farmers were not efficiently trained by agricultural cooperatives on improved rice production techniques. Moreso, there were no significant difference on the extent of carrying out the training of male and female farmers by agricultural cooperatives on improved rice production techniques in Ini Local Government Area. It is recommended among others that Agricultural cooperatives should organize periodic training sessions for rice farmers through the use of facilities and demonstration in the farm. The Government, through The Ministry of Agriculture should encourage and support agricultural cooperatives by providing materials and adequate funding to enable them perform their primary assignment creditably

Improving Crude Oil Contaminated Soil with Organic Amendments: Effect of Oil Palm Bunch Ash and Dried Poultry Litters on Soil Properties and Cassava Growth and Yields

In this study, onsite field experiments were carried out to evaluate the effects of amending a crude oil polluted soil with oil palm fruit bunch ash (OPFBA), dried poultry litters (DPL), soil bacterial, physico-chemical properties, as well as the growth and tuber yield of cassava (Manihot esculenta CRANTZ) grown on the amended soils using standard techniques. Results of autotrophic bacteria counts revealed that nitrogen fixing bacteria (NFB) populations in soils treated with OPBA+DPL combined, OPBA and DPL singly, recorded high bioloads in the magnitude of 105 , 103 , 105 CFU/g of soil respectively, whereas the group mean population was lower in the control soil (103 CFU/g). Similar trends were observed for SRB, PSB, and THB. Results of aggregate growth showed that while the mean plant heights and number of nodes increased, stem girth and leaf area were observed to decrease in 2017 when compared with those of 2016. Apart from number of tubers and weights that showed increase under all amendment treatments, tuber girth and length decreased under DPL amendments in 2017. The average findings of several chemical and physical characteristics of crude oil polluted soil after amendments and subsequent cultivation demonstrated that the addition of DPL and OPBA fructifies the soil by increasing reduced or lost qualities. When the amendments were used, the concentrations of organic carbon, accessible phosphorus, Ca, Mg, Na, and K were greatly enhanced, while the Total Petroleum Hydrocarbon (TPH) content was significantly reduced. In this study, the application of combination DPL + OPBA yields the greatest results in terms of ameliorating the impacts of crude oil in cultivable soils, as it increases fertility parameters for better cassava production in Niger Delta soils. The technology has been shown to be cost effective, efficient, and environmentally friendly, as well as capable of resolving waste management issues

Effect of Intercropping Leguminous Tree Species on Soil Nutrient Status, Growth and Yield of Arable Crops in Ukan Edemaya, Ikot Abasi Local Government Area, Akwa Ibom State, Nigeria

Intercropping improves the usage rate of a land while also maintaining soil fertility. This study is to examine the preliminary intercropping effect of leguminous trees species (Leucaena leucocephala (Lam), Gliricidia sepium (Jacq), and Senna siamae (Lam) on soil nutrient status, growth and yield of arable crops (Zea mays L) in two cropping seasons (2017 and 2018) using a field trial at Ukan Edemaya, Ikot Abasi Local Government Area of Akwa Ibom State, Nigeria. Treatments were randomized within the blocks and reproduced four (4) times on a 0.04 hectare plot of land that was cleared, demarcated into four blocks, and manually tilled. The study was a two-factor factorial using a Randomized Complete Block Design layout (RCBC). The data was analyzed using Analysis of Variance (ANOVA), and treatment means were separated using Least Significant Difference (LSD < 0.05). The findings revealed that all arable crop growth and production were not significant in weeks 1-6 (WAP), but significant from weeks 7 to 14 (WAP). Arable crops planted in leucaena alleys outperformed those planted in Gliricidia and senna alleys and outperformed those planted in plots without leguminous plants. Leguminous tree species were shown to boost the growth and yield of arable crops, as well as rehabilitate a damaged fertility soil quality, according to the study. Farmers are urged to intercrop their arable crops with leguminous tree species in order to increase yield and provide fuel wood

Adaptive tuning functions arise from visual observation of past movement

Visual observation of movement plays a key role in action. For example, tennis players have little time to react to the ball, but still need to prepare the appropriate stroke. Therefore, it might be useful to use visual information about the ball trajectory to recall a specific motor memory. Past visual observation of movement (as well as passive and active arm movement) affects the learning and recall of motor memories. Moreover, when passive or active, these past contextual movements exhibit generalization (or tuning) across movement directions. Here we extend this work, examining whether visual motion also exhibits similar generalization across movement directions and whether such generalization functions can explain patterns of interference. Both the adaptation movement and contextual movement exhibited generalization beyond the training direction, with the visual contextual motion exhibiting much broader tuning. A second experiment demonstrated that this pattern was consistent with the results of an interference experiment where opposing force fields were associated with two separate visual movements. Overall, our study shows that visual contextual motion exhibits much broader (and shallower) tuning functions than previously seen for either passive or active movements, demonstrating that the tuning characteristics of past motion are highly dependent on their sensory modality

Engaging students in scenario-based assessment for final exams

We present our approaches to enhancing the authenticity of final exams across large first-year first semester biology units of cohort sizes between 300-1200 students. Historically exams were primarily used as an instrument that mainly assessed knowledge retention with limited provision of feedback to students. The necessity to shift to online learning during the height of the COVID-19 pandemic provided us with a challenging, yet opportune moment to transform our final examinations into an authentic learning experience for undergraduate biology students. We placed a large focus on integrating scenario-based questions in the final exam thereby assessing students’ ability to apply knowledge to real-world contexts. To enhance engagement with the assessment, we also provided personalised feedback for each student. With additional challenges around access to artificial intelligence and academic integrity, we share our experiences returning to in-person final examinations and evaluate the relevancy and benefits of scenario-based questions for student assessment and learning. We also share our approaches to feedforwarding initiatives to prepare students for examinations that is different to what most students would have experienced in their secondary schooling

A model of open-loop control of equilibrium position and stiffness of the human elbow joint

According to the equilibrium point theory, the control of posture and movement involves the setting of equilibrium joint positions (EP) and the independent modulation of stiffness. One model of EP control, the α-model, posits that stable EPs and stiffness are set open-loop, i.e. without the aid of feedback. The purpose of the present study was to explore for the elbow joint the range over which stable EPs can be set open-loop and to investigate the effect of co-contraction on intrinsic low-frequency elbow joint stiffness (