Clinical malaria case definition and malaria attributable fraction in the highlands of western Kenya

BACKGROUND: In African highland areas where endemicity of malaria varies greatly according to altitude and topography, parasitaemia accompanied by fever may not be sufficient to define an episode of clinical malaria in endemic areas. To evaluate the effectiveness of malaria interventions, age-specific case definitions of clinical malaria needs to be determined. Cases of clinical malaria through active case surveillance were quantified in a highland area in Kenya and defined clinical malaria for different age groups. METHODS: A cohort of over 1,800 participants from all age groups was selected randomly from over 350 houses in 10 villages stratified by topography and followed for two-and-a-half years. Participants were visited every two weeks and screened for clinical malaria, defined as an individual with malaria-related symptoms (fever [axillary temperature ≥ 37.5°C], chills, severe malaise, headache or vomiting) at the time of examination or 1–2 days prior to the examination in the presence of a Plasmodium falciparum positive blood smear. Individuals in the same cohort were screened for asymptomatic malaria infection during the low and high malaria transmission seasons. Parasite densities and temperature were used to define clinical malaria by age in the population. The proportion of fevers attributable to malaria was calculated using logistic regression models. RESULTS: Incidence of clinical malaria was highest in valley bottom population (5.0% cases per 1,000 population per year) compared to mid-hill (2.2% cases per 1,000 population per year) and up-hill (1.1% cases per 1,000 population per year) populations. The optimum cut-off parasite densities through the determination of the sensitivity and specificity showed that in children less than five years of age, 500 parasites per μl of blood could be used to define the malaria attributable fever cases for this age group. In children between the ages of 5–14, a parasite density of 1,000 parasites per μl of blood could be used to define the malaria attributable fever cases. For individuals older than 14 years, the cut-off parasite density was 3,000 parasites per μl of blood. CONCLUSION: Clinical malaria case definitions are affected by age and endemicity, which needs to be taken into consideration during evaluation of interventions

Predictive Value of Fever and Palmar Pallor for P. falciparum Parasitaemia in Children from an Endemic Area

INTRODUCTION: Although the incidence of Plasmodium falciparum malaria in some parts of sub-Saharan Africa is reported to decline and other conditions, causing similar symptoms as clinical malaria are gaining in relevance, presumptive anti-malarial treatment is still common. This study traced for age-dependent signs and symptoms predictive for P. falciparum parasitaemia. METHODS: In total, 5447 visits of 3641 patients between 2-60 months of age who attended an outpatient department (OPD) of a rural hospital in the Ashanti Region, Ghana, were analysed. All Children were examined by a paediatrician and a full blood count and thick smear were done. A Classification and Regression Tree (CART) model was used to generate a clinical decision tree to predict malarial parasitaemia a7nd predictive values of all symptoms were calculated. RESULTS: Malarial parasitaemia was detected in children between 2-12 months and between 12-60 months of age with a prevalence of 13.8% and 30.6%, respectively. The CART-model revealed age-dependent differences in the ability of the variables to predict parasitaemia. While palmar pallor was the most important symptom in children between 2-12 months, a report of fever and an elevated body temperature of ≥37.5°C gained in relevance in children between 12-60 months. The variable palmar pallor was significantly (p<0.001) associated with lower haemoglobin levels in children of all ages. Compared to the Integrated Management of Childhood Illness (IMCI) algorithm the CART-model had much lower sensitivities, but higher specificities and positive predictive values for a malarial parasitaemia. CONCLUSIONS: Use of age-derived algorithms increases the specificity of the prediction for P. falciparum parasitaemia. The predictive value of palmar pallor should be underlined in health worker training. Due to a lack of sensitivity neither the best algorithm nor palmar pallor as a single sign are eligible for decision-making and cannot replace presumptive treatment or laboratory diagnosis

14-3-3σ Regulates β-Catenin-Mediated Mouse Embryonic Stem Cell Proliferation by Sequestering GSK-3β

[[abstract]]Background: Pluripotent embryonic stem cells are considered to be an unlimited cell source for tissue regeneration and cell-based therapy. Investigating the molecular mechanism underlying the regulation of embryonic stem cell expansion is thus important. 14-3-3 proteins are implicated in controlling cell division, signaling transduction and survival by interacting with various regulatory proteins. However, the function of 14-3-3 in embryonic stem cell proliferation remains unclear. Methodology and Principal Findings: In this study, we show that all seven 14-3-3 isoforms were detected in mouse embryonic stem cells. Retinoid acid suppressed selectively the expression of 14-3-3σ isoform. Knockdown of 14-3-3σ with siRNA reduced embryonic stem cell proliferation, while only 14-3-3σ transfection increased cell growth and partially rescued retinoid acid-induced growth arrest. Since the growth-enhancing action of 14-3-3σ was abrogated by β-catenin knockdown, we investigated the influence of 14-3-3σ overexpression on β-catenin/GSK-3β. 14-3-3σ bound GSK-3β and increased GSK-3β phosphorylation in a PI-3K/Akt-dependent manner. It disrupted β-catenin binding by the multiprotein destruction complex. 14-3-3σ overexpression attenuated β-catenin phosphorylation and rescued the decline of β-catenin induced by retinoid acid. Furthermore, 14-3-3σ enhanced Wnt3a-induced β-catenin level and GSK-3β phosphorylation. DKK, an inhibitor of Wnt signaling, abolished Wnt3a-induced effect but did not interfere GSK-3β/14-3-3σ binding. Significance:Our findings show for the first time that 14-3-3σ plays an important role in regulating mouse embryonic stem cell proliferation by binding and sequestering phosphorylated GSK-3β and enhancing Wnt-signaled GSK-3β inactivation. 14-3-3σ is a novel target for embryonic stem cell expansion

Gaze-based hints during child-robot gameplay

\u3cp\u3eThis paper presents a study that examines whether gaze hints provided by a robot tutor influences the behavior of children in a card matching game. In this regard, we conducted a within-subjects experiment, in which children played a card game “Memory” in the presence of a robot tutor in two sessions. In one session (Help), the robot tutor gives gaze hints to help children find matching cards and, in the other session (No_Help), the robot tutor does not provide help to the children. Gaze hints involved looking toward the correct matching cart. We analyzed the child-robot interaction regarding execution performance, gaze behavior, and level of engagement. Children performance was measured using the number of trials and overall time used to complete the game. We found that children used significantly fewer trials in the Help condition than in the No_Help condition. In addition, there were more instances of mutual gaze in the Help condition than in the No_Help condition. These findings suggest that designing a robot with dynamic gaze increases the effectiveness of the robot tutor as a helping agent.\u3c/p\u3

Dyadic gaze patterns during child-robot collaborative gameplay in a tutoring interaction

\u3cp\u3eThis study examines patterns of coordinated gaze between a child and a robot (NAO) during a card matching game, 'Memory'. Dyadic gaze behavior like mutual gaze, gaze following and joint attention are indications both of child's engagement with the robot and of the quality of child-robot interaction. Eighteen children interacted with a robot tutor in two settings. In the first setting, the robot tutor gave clues to assist children in finding the matching cards, and in the other setting, the robot tutor only looked at the participants during the play. We investigated the coordination between child and robots' gaze behaviors. We found that more occurrences of mutual gaze and gaze following made the children aware of the gaze hints given by the robot and improved the efficacy of the robot tutor as a helping agent. This study, therefore, provides guidelines for gaze behaviors design to enrich child-robot interaction in a tutoring context.\u3c/p\u3

Can children take advantage of nao gaze-based hints during gameplay?

\u3cp\u3eThis paper presents a study that analyzes the effects of robots' gaze hints on children's performance in a card-matching game. We conducted a within-subjects study, in which children played a card matching game Memory in the presence of a robot tutor in two sessions. In one session, the robot gave hints to help the child find matching cards by looking at the correct match and, in the other session, the robot only looked at the child and did not give them any help. Children performance was measured using the number of tries and overall time used to complete the game. Our findings show that the use of gaze hints (help condition) made the matching task significantly easier and that children used significantly fewer tries than without help.\u3c/p\u3

Who is a better tutor?:gaze hints with a human or humanoid tutor in game play

\u3cp\u3eIn this paper, we present a study that analyses the effects of robot or human gaze hints on people's choices in a card game. We asked human participants to play a matching card game in the presence of a human or a robotic tutor. Our aim was to find out if gaze hints provided by the tutor can direct the attention and influence the choices of the human participants. The results show that participants performed significantly better when they received gaze hints from a tutor than when they did not. Furthermore, we found that people identified the tutor hints more often in robot condition than in human condition and, as a result, performed significantly better.\u3c/p\u3

Directing attention through gaze hints improves task solving in human–humanoid interaction

\u3cp\u3eIn this paper, we report an experimental study designed to examine how participants perceive and interpret social hints from gaze exhibited by either a robot or a human tutor when carrying out a matching task. The underlying notion is that knowing where an agent is looking at provides cues that can direct attention to an object of interest during the activity. In this regard, we asked human participants to play a card matching game in the presence of either a human or a robotic tutor under two conditions. In one case, the tutor gave hints to help the participant find the matching cards by gazing toward the correct match, in the other case, the tutor only looked at the participants and did not give them any help. The performance was measured based on the time and the number of tries taken to complete the game. Results show that gaze hints (helping tutor) made the matching task significantly easier (fewer tries) with the robot tutor. Furthermore, we found out that the robots’ gaze hints were recognized significantly more often than the human tutor gaze hints, and consequently, the participants performed significantly better with the robot tutor. The reported study provides new findings towards the use of non-verbal gaze hints in human–robot interaction, and lays out new design implications, especially for robot-based educative interventions.\u3c/p\u3

See where I am looking at : perceiving gaze cues with a NAO robot

Gaze is an important nonverbal cue in human - human communication, for example, in communicating direction of attention. Therefore, presumably being able to understand and provide gaze cues is an important aspect in robot's interactive behavior. While there is considerable progress, as regards the design of social gaze cues for robots, there is little that has been done to examine the ability of humans to read and accept help signals from a robot's gaze. In this study, we examine how people perceive gaze cues and head angles directed towards different target positions on a table when human and NAO robot are sitting against each other as in board game scenarios. From the results, we show that when the head pitch angle is higher (24±2) and the depth is less, approximately 20 cm from the robot, participants detected the positions with good accuracy. Unexpectedly, the locations on the left of the robot were detected with lower accuracy. In conclusion, we discuss the implications of this research for design of interaction settings between human and a robot that is intended for social and educational support

Personalizing educational game play with a robot partner

Personalization of educational and behavioral training to the developmental stage of the individual child is common practice in educational and therapeutic settings. Research on robot-based education training is only just starting to adopt this approach. We present a pilot study on a behavioral intervention design in which Pivotal Response Training (PRT) elements are embedded into a game played by a robot and a child. Seven game levels are designed to cover different levels of communication skills that are targeted by PRT. The levels do not differ with respect to the logical steps in the game that the children should take, only with respect to the social competence that the child has. The behaviors displayed at each stage were observed and analyzed using qualitative and quantitative methods. Our results indicate that the more socially challenging a game is, the happier children are and the more children engage with playing the game, although the game challenge remains the sam