Bounds on end-to-end performance of networks employing erasure control coding

Erasure control coding has been exploited in communication networks with an aim to improve the end-to-end performance of data delivery across the network. To address the concerns over the strengths and constraints of erasure coding schemes in this application, we examine the performance limits of two erasure control coding strategies, forward erasure recovery and adaptive erasure recovery. Our investigation shows that the throughput of a network using an (n, k) forward erasure control code is capped by r =k/n when the packet loss rate p ≤ (te/n) and by k(l-p)/(n-te) when p > (t e/n), where te is the erasure control capability of the code. It also shows that the lower bound of the residual loss rate of such a network is (np-te)/(n-te) for (te/n) < p ≤ 1. Especially, if the code used is maximum distance separable, the Shannon capacity of the erasure channel, i.e. 1-p, can be achieved and the residual loss rate is lower bounded by (p+r-1)/r, for (1-r) < p ≤ 1. To address the requirements in real-time applications, we also investigate the service completion time of different schemes. It is revealed that the latency of the forward erasure recovery scheme is fractionally higher than that of the scheme without erasure control coding or retransmission mechanisms (using UDP), but much lower than that of the adaptive erasure scheme when the packet loss rate is high. Results on comparisons between the two erasure control schemes exhibit their advantages as well as disadvantages in the role of delivering end-to-end services. To show the impact of the bounds derived on the end-to-end performance of a TCP/IP network, a case study is provided to demonstrate how erasure control coding could be used to maximize the performance of practical systems. © 2010 IEEE.

Temporal Coding of Volumetric Imagery

'Image volumes' refer to realizations of images in other dimensions such as time, spectrum, and focus. Recent advances in scientific, medical, and consumer applications demand improvements in image volume capture. Though image volume acquisition continues to advance, it maintains the same sampling mechanisms that have been used for decades; every voxel must be scanned and is presumed independent of its neighbors. Under these conditions, improving performance comes at the cost of increased system complexity, data rates, and power consumption.

This dissertation explores systems and methods capable of efficiently improving sensitivity and performance for image volume cameras, and specifically proposes several sampling strategies that utilize temporal coding to improve imaging system performance and enhance our awareness for a variety of dynamic applications.

Video cameras and camcorders sample the video volume (x,y,t) at fixed intervals to gain understanding of the volume's temporal evolution. Conventionally, one must reduce the spatial resolution to increase the framerate of such cameras. Using temporal coding via physical translation of an optical element known as a coded aperture, the compressive temporal imaging (CACTI) camera emonstrates a method which which to embed the temporal dimension of the video volume into spatial (x,y) measurements, thereby greatly improving temporal resolution with minimal loss of spatial resolution. This technique, which is among a family of compressive sampling strategies developed at Duke University, temporally codes the exposure readout functions at the pixel level.

Since video cameras nominally integrate the remaining image volume dimensions (e.g. spectrum and focus) at capture time, spectral (x,y,t,\lambda) and focal (x,y,t,z) image volumes are traditionally captured via sequential changes to the spectral and focal state of the system, respectively. The CACTI camera's ability to embed video volumes into images leads to exploration of other information within that video; namely, focal and spectral information. The next part of the thesis demonstrates derivative works of CACTI: compressive extended depth of field and compressive spectral-temporal imaging. These works successfully show the technique's extension of temporal coding to improve sensing performance in these other dimensions.

Geometrical optics-related tradeoffs, such as the classic challenges of wide-field-of-view and high resolution photography, have motivated the development of mulitscale camera arrays. The advent of such designs less than a decade ago heralds a new era of research- and engineering-related challenges. One significant challenge is that of managing the focal volume (x,y,z) over wide fields of view and resolutions. The fourth chapter shows advances on focus and image quality assessment for a class of multiscale gigapixel cameras developed at Duke.

Along the same line of work, we have explored methods for dynamic and adaptive addressing of focus via point spread function engineering. We demonstrate another form of temporal coding in the form of physical translation of the image plane from its nominal focal position. We demonstrate this technique's capability to generate arbitrary point spread functions.

An Interactive Model to Teach Motor Skills

There has been a tremendous increase in our knowledge of hum motor performance over the last few decades. Our theoretical understanding of how an individual learns to move is sophisticated and complex. It is difficult however to relate much of this information in practical terms to physical educators, coaches, and therapists concerned with the learning of motor skills (Shumway-Cook & Woolcott, 1995). Much of our knowledge stems from lab testing which often appears to bear little relation to real-life situations. This lack of ecological validity has slowed the flow of information from the theorists and researchers to the practitioners. This paper is concerned with taking some small aspects of motor learning theory, unifying them, and presenting them in a usable fashion. The intention is not to present a recipe for teaching motor skills, but to present a framework from which solutions can be found. If motor performance research has taught us anything, it is that every individual and situation presents unique challenges. By increasing our ability to conceptualize the learning situation we should be able to develop more flexible and adaptive responses to the challege of teaching motor skills. The model presented here allows a teacher, coach, or therapist to use readily available observations and known characteristics about a motor task and to conceptualize them in a manner which allows them to make appropriate teaching/learning decisions.

Parallel nonconvex generalized Benders decomposition for natural gas production network planning under uncertainty

A scenario-based two-stage stochastic programming model for gas production network planning under uncertainty is usually a large-scale nonconvex mixed-integer nonlinear programme (MINLP), which can be efficiently solved to global optimality with nonconvex generalized Benders decomposition (NGBD). This paper is concerned with the parallelization of NGBD to exploit multiple available computing resources. Three parallelization strategies are proposed, namely, naive scenario parallelization, adaptive scenario parallelization, and adaptive scenario and bounding parallelization. Case study of two industrial natural gas production network planning problems shows that, while the NGBD without parallelization is already faster than a state-of-the-art global optimization solver by an order of magnitude, the parallelization can improve the efficiency by several times on computers with multicore processors. The adaptive scenario and bounding parallelization achieves the best overall performance among the three proposed parallelization strategies.

Securing the Anthropocene? International Policy Experiments in Digital Hacktivism: A Case Study of Jakarta

This article analyses security discourses that are beginning to self-consciously take on board the shift towards the Anthropocene. Firstly, it sets out the developing episteme of the Anthropocene, highlighting the limits of instrumentalist cause-and-effect approaches to security, increasingly becoming displaced by discursive framings of securing as a process, generated through new forms of mediation and agency, capable of grasping inter-relations in a fluid context. This approach is the methodology of hacking: creatively composing and repurposing already existing forms of agency. It elaborates on hacking as a set of experimental practices and imaginaries of securing the Anthropocene, using as a case study the field of digital policy activism with the focus on community empowerment through social-technical assemblages being developed and applied in ‘the City of the Anthropocene’: Jakarta, Indonesia. The article concludes that policy interventions today cannot readily be grasped in modernist frameworks of ‘problem solving’ but should be seen more in terms of evolving and adaptive ‘life hacks’.

Community-led upgrading for self-reliance in informal settlements in South Africa: a review

Around the world, informal and low-income settlements (so-called “slums”) have been a major issue in city management and environmental sustainability in developing countries. Overall, African cities have an agenda for slum management and response. For example, the South African government introduced the Upgrade of Informal Settlements Program (UISP), as a comprehensive plan for upgrading slum settlements. Nevertheless, upgrading informal settlements from the bottom-up is key to inform broad protocols and strategies for sustainable communities and `adaptive cities´. Community-scale schemes can drive sustainability from the bottom-up and offer opportunities to share lessons learnt at the local level. Key success factors in their roll-out are: systems thinking; empowered local authorities that support decentralised solutions and multidisciplinary collaboration between the involved actors, including the affected local population. This research lies under the umbrella of sustainable bottom-up urban regeneration. As part of a larger project of collaboration between UK and SA research institutions, this paper presents an overview of in-situ participatory upgrade as an incremental strategy for upgrading informal settlements in the context of sustainable and resilient city. The motivation for this research is rooted in identifying the underpinning barriers and enabling drivers for up-scaling community-led, participatory upgrading approaches in informal settlements in the metropolitan area. This review paper seeks to provide some preliminary guidelines and recommendations for an integrated collaborative environmental and construction management framework to enhance community self-reliance. A theoretical approach based on the review of previous studies was combined with a pilot study conducted in Durban (South Africa) to investigate the feasibility of community-led upgrading processes.

A Influência de um Curso de Meditação nos Níveis de Mindfulness, Satisfação com a Vida e Optimismo

O mindfulness tem sido alvo de um crescente interesse no domínio da Psicologia e a sua importância ao nível do funcionamento psicológico tem vindo a ser empiricamente verificada. Os estudos sobre mindfulness têm demonstrado que este constructo está positivamente relacionado com a saúde psicológica e negativamente com a psicopatologia. Deste modo, a presente investigação teve como objectivo compreender a relação entre mindfulness, satisfação com a vida e optimismo, bem como explicar a influência de um curso de meditação nestas variáveis. Neste sentido, os participantes completaram uma bateria de questionários de auto-resposta avaliando o mindfulness, satisfação com a vida e optimismo num primeiro momento de avaliação, antes do curso de meditação (N = 104), num segundo momento, depois do curso de meditação (N = 30). Os resultados revelam um aumento significativo nos níveis de mindfulness, satisfação com a vida e optimismo após a frequência do curso de meditação e indicam que a prática do curso de meditação fortalece a relação entre estes constructos. Apesar de algumas limitações metodológicas que futura investigação deverá tentar colmatar, este estudo reforça a importância da prática de meditação para um funcionamento psicológico positivo e adaptativo. / Mindfulness has been target of a growing interest to Psychology in terms of the verified importance to psychological function. Studies show that mindfulness has demonstrated an important correlation with psychological health and negatively to psychopathology. The objective of the present research is to understand the relation between mindfulness, satisfaction with life and optimism as well as to explain the influence of a course of meditation in the study of these variables. The participants of this research completed several different types of auto-response questionnaires regarding mindfulness, satisfaction with life, and optimism; prior to the meditation course (N = 104), and then, after the meditation course (N = 30). Therefore, the results of the research demonstrated that the level of mindfulness, satisfaction with life and optimism significantly increased as the participants undergone in the meditation course as well as indicated that the practice such course strengthens the relation between the variables. Despite some methodological limitations that a future research should relieve, this study reinforces the practice of meditation for a positive and adaptive psychological function.

Methods, Models & Systems for Dealing with Some Business, Management & Engineering Problems

This keynote presentation will report some of our research work and experience on the development and applications of relevant methods, models, systems and simulation techniques in support of different types and various levels of decision making for business, management and engineering. In particular, the following topics will be covered. Modelling, multi-agent-based simulation and analysis of the allocation management of carbon dioxide emission permits in China (Nanfeng Liu & Shuliang Li Agent-based simulation of the dynamic evolution of enterprise carbon assets (Yin Zeng & Shuliang Li) A framework & system for extracting and representing project knowledge contexts using topic models and dynamic knowledge maps: a big data perspective (Jin Xu, Zheng Li, Shuliang Li & Yanyan Zhang) Open innovation: intelligent model, social media & complex adaptive system simulation (Shuliang Li & Jim Zheng Li) A framework, model and software prototype for modelling and simulation for deshopping behaviour and how companies respond (Shawkat Rahman & Shuliang Li) Integrating multiple agents, simulation, knowledge bases and fuzzy logic for international marketing decision making (Shuliang Li & Jim Zheng Li) A Web-based hybrid intelligent system for combined conventional, digital, mobile, social media and mobile marketing strategy formulation (Shuliang Li & Jim Zheng Li) A hybrid intelligent model for Web & social media dynamics, and evolutionary and adaptive branding (Shuliang Li) A hybrid paradigm for modelling, simulation and analysis of brand virality in social media (Shuliang Li & Jim Zheng Li) Network configuration management: attack paradigms and architectures for computer network survivability (Tero Karvinen & Shuliang Li)

Farmers' Resilience to Climate Change in the Welsh Marshes

Climate change will exacerbate challenges facing food security in the UK. Increasing frequency and intensity of extreme weather events will further impact upon farm systems. At the heart of the impending challenges to UK agricultural production, farmers’ resilience will be tested to new limits. Research into farmers’ resilience to climate change in the UK is distinctly underdeveloped when compared to research in developing and other developed nations. This research gap is addressed through exploration of farmers’ resilience in the Welsh Marches, establishing the role of risk perceptions, local knowledge and adaptive capacity in farmers’ decision-making to limit climate shocks. Further contributions to agricultural geography are made through experimentation of a ‘cultural-behavioural approach’, seeking to revisit the behavioural approach in view of the cultural-turn. The Welsh Marches, situated on the English-Welsh border, has been selected as a focal point due to its agricultural diversity, and known experiences of extreme weather events. A phased mixed methodological approach is adopted. Phase one explores recorded and reported experiences of past extreme weather events in local meteorological records and local newspaper articles. Phase two consists of 115 survey-questionnaires, 15 in-depth semi-structured interviews, and a scenario based focus group with selected farmers from the Welsh Marches. This allows farmers’ resilience to climate change in the past, present and future to be explored. Original contributions to knowledge are made through demonstrating the value of focusing upon the culture of a specific farm community, applying a ‘bottom-up’ approach. The priority given to the weather in farmers’ decision-making is identified to be determined by individual relationships that farmers’ develop with the weather. Yet, a consensus of farmers’ observations has established recognition of considerable changes in the weather over the last 30 years, acknowledging more extremes and seasonal variations. In contrast, perceptions of future climate change are largely varied. Farmers are found to be disengaged with the communication of climate change science, as the global impacts portrayed are distant in time and place from probable impacts that may be experienced locally. Current communication of climate change information has been identified to alienate farmers from the local reality of probable future impacts. Adaptation options and responses to extreme weather and climate change are identified from measures found to be already implemented and considered for the future. A greater need to explore local knowledge and risk perception in relation to farmers’ understanding of future climate challenges is clear. There is a need to conduct comparable research in different farm communities across the UK. Progression into establishing the role of farmers’ resilience in responding effectively to future climate challenges has only just begun.

The Welsh Marches: Resilient Farmers? Exploring Farmers' Resilience to Extreme Weather Events in the Recent Past

In the 21st century climate change will cause a significant increase in the frequency and intensity of extreme weather events across Europe. Investigating farmers’ resilience to extreme weather events in the past can be used to establish the inherent level of resilience farmers’ will have to respond to comparable events in the future. The Welsh Marches has experienced a range of extreme weather events including: heatwaves, flooding; prolonged rainfall; and heavy snowfall. To identify the resilience of farmers in the Marches farmers’ apparent vulnerabilities, coping capacity, social capital and adaptive capacity that have been exposed in past events are discussed. Rural isolation is identified as an exacerbating factor of farming vulnerability. Yet, this is also an apparent source of resilience as farmers are found to rely on high social capital to assist each other in emergency and challenging situations during extreme weather events. The paper concludes by indicating that more localised studies are required, situated within unique farming cultures. This will enable a more complete picture of farmers’ resilience across Europe to be established.

Symmetric Interior Penalty DG Methods for the Compressible Navier-Stokes Equations II: Goal--Oriented A Posteriori Error Estimation

In this article we consider the application of the generalization of the symmetric version of the interior penalty discontinuous Galerkin finite element method to the numerical approximation of the compressible Navier--Stokes equations. In particular, we consider the a posteriori error analysis and adaptive mesh design for the underlying discretization method. Indeed, by employing a duality argument (weighted) Type I a posteriori bounds are derived for the estimation of the error measured in terms of general target functionals of the solution; these error estimates involve the product of the finite element residuals with local weighting terms involving the solution of a certain dual problem that must be numerically approximated. This general approach leads to the design of economical finite element meshes specifically tailored to the computation of the target functional of interest, as well as providing efficient error estimation. Numerical experiments demonstrating the performance of the proposed approach will be presented.

The psychometric properties of the brief Other as Shamer Scale for Children (OAS‐C) : preliminary validation studies in a sample of Portuguese children

Shame is a social emotion with adaptive functions involved in human be-havior and social interactions. This emotion is regarded as an involuntary response associated with increased self-awareness, loss of status and self-devaluation (Gilbert, 1998), that may render individuals more prone to psychopathology (Gilbert, 1998; Pinto-Gouveia & Matos, 2011). Thus, identifying and assessing feelings of shame in childhood is essential in addressing the actual impact of shame on individual’s developmental trajectory. The Other As Shamer Scale (OAS; Goss, Gilbert & Allan, 1994) is a widely used measure of external shame, adapted and translated to several languages — including Portuguese (Matos, Pinto-Gouveia, Gilbert, Duarte & Figueiredo, 2015) — to adult and to adolescent populations (OASB-A - Other As Shamer Brief for adolescents; translated and adapted by Cunha, Xavier, Cherpe & Pinto-Gouveia, 2014). The current study aims to adapt and to explore the psychometric proper-ties of the brief OAS in a sample of Portuguese children attending to elementary schools.

Técnicas de manejo agropecuário sustentável

The competitiveness in the rural sector and the need to make viable and sustainable property, direct the farmer to seek new production strategies. In this sense, the book Techniques of sustainable agricultural management has as objective contributed information on concepts, management practices, technological innovations, which are applicable in the agricultural production. The same is composed of 13 chapters, topics covered in aquaculture production, management and dairy production, as general aspects of hematology fish; dynamics of decision-making and adaptive flow dairy production systems; importance of performance measures and body biometrics in small ruminants; milk production in beef cows; parasitism in beef cattle; performance of dairy cows in production; efficiency of cross beef cattle in finishing phase; development of Marchangus: five years; and, bovine growth efficiency. In vegetable production area are addressed matters relating on management and olive cultivation, species of great economic importance and diversification as alternative on the property; functional foods in fruit and vegetables; influence of environmental factors, harvesting and drying in the production and composition of essential oils of Mentha spp; and, implication of the contamination of corn grain by mycotoxins in livestock production. At the end of the book, the expectation of the authors is to have contributed with relevant themes of Brazilian agriculture, which could reflect positively on knowledge, values and quality of available material.

An Agent-based Classification Model

The major function of this model is to access the UCI Wisconsin Breast Cancer data-set[1] and classify the data items into two categories, which are normal and anomalous. This kind of classification can be referred as anomaly detection, which discriminates anomalous behaviour from normal behaviour in computer systems. One popular solution for anomaly detection is Artificial Immune Systems (AIS). AIS are adaptive systems inspired by theoretical immunology and observed immune functions, principles and models which are applied to problem solving. The Dendritic Cell Algorithm (DCA)[2] is an AIS algorithm that is developed specifically for anomaly detection. It has been successfully applied to intrusion detection in computer security. It is believed that agent-based modelling is an ideal approach for implementing AIS, as intelligent agents could be the perfect representations of immune entities in AIS. This model evaluates the feasibility of re-implementing the DCA in an agent-based simulation environment called AnyLogic, where the immune entities in the DCA are represented by intelligent agents. If this model can be successfully implemented, it makes it possible to implement more complicated and adaptive AIS models in the agent-based simulation environment.

Studies on the protective immune response to Plasmodium chabaudi in mice

Inbred strains of C5731 and NIH nice infected with the A/S strain of Plasmodium chaubaudi usually developed high parasitaemias but infections were rarely fatal in immunocompetent mice and in most mice the parasites could be eradicated within 53 days or less. The immune response of C57B1 and NTH mice to infection with the A/S strain of P. chabaudi was studied. The principle method used in this study for investigating the immune response of the mice was to examine the immunity conferred on syngeneic mice, either X-irradiated or non-irradiated, by transferring to them lymphoid cells or serum from immune or semi-immune donors. The lymphoid cell populations examined were unfractionated spleen cells, nylon wool column enriched subpopulations of thymus-derived lymphocytes (T cells) and the so-called bursa-derived lymphocytes (B cells), bone marrow cells and phagocytic cells. In the course of these experiments observations were made on the effect of X-irradiation on the subsequent growth and multiplication of the parasite. In addition, an in vitro assay for antibody-dependent cell mediated cytotoxicity was used to investigate the activity of splenic K cells during malaria infection. K cells are lymphoid cells which may include lymphocytes of an undefined category, but possess receptors for the Fc portion of antibody on their surface and have the ability to non-specifically lyse target cells coated in antibodies. a) The adoptive transfer of immunity to P.chabaudi with immune spleen cells. Spleen cells from mice which had previously been infected with P.chabaudi were able to confer some immunity on syngeneic mice which had been irradiated with 600 or 800 rads. The protection was detected as a shortened patent parasitaemia in immune cell recipients compared to controls. The early experiments indicated the value of using irradiated recipients rather than non-irradiated recipients. In irradiated mice, a) smaller numbers of immune cells were required to promote detectable immunity than in non-irradiated mice, b) there was an amplification of the difference in the duration of primary parasitaemias in recipients of immune cells and normal cells compared to non-irradiated mice and c) as the irradiated host is immunodepressed, the protective effect of donor cells can be examined with a reduced contribution by the hosts own immune system. An initial non-specific resistance to P.chabaudi infection was observed in irradiated mice, although the infection in most of these mice was subsequently more severe than in non-irradiated mice. The non-specific resistance could be reduced or abolished by injecting lymphoid cells into mice shortly after irradiation or by infecting irradiated mice more than 15 days after irradiation. Other workers suggest that following irradiation, the reticulo-endothelial system is stimulated at the time that the non-specific resistance to P.chabaudi was observed. b) the adoptive transfer of immunity in syngeneic mice with enriched subpopulations of splenic immune T cells, B. cells, bone marrow cells and phagocytes. Immunity to P.chabaudi could be adoptively transferred with enriched spleen subpopulations of immune T cells or immune B cells in mice which had been irradiated 600 or 300 rads. The protective effects of unfractionated immune cells was, however, usually better than that of either immune T or F cell subpopulations. In most experiments enriched immune T cell recipients were more likely to suffer relapsing patent parasitaemias than either enriched immune B cell recipients or unfractionated immune cell recipients. In one experiment a comparison was made of the course of P.chabaudi infection in mice which had been irradiated with either 600 rads or 300 rads and which received injections of different immune cells. A dose of 600 rads permits the immune system of mice to recover from the effects of irradiation, but a dose of 800 rads is lethal to mice unless lymphoid cells are injected after irradiation. It was found that in recipients of enriched immune T or B cells, which had been irradiated with 600 rads, the parasitaemia became subpatent before their equivalents irradiated with 800 rads, but that there was little difference in parasitaemias between recipients of unfractionated immune cells given 600 or 800 rads. Experiments in which enriched immune T cells and B cells were recombined and injected into syngeneic mice gave inconclusive results as to whether the immune subpopulations acted synergistically. Similar experiments in which immune subpopulations of lymphoid cells were recombined with normal subpopulations of lymphoid cells demonstrated that the latter cells did not enhance the protective effect of the former cells. Bone marrow cells from immune mice were able to confer some protection on syngeneic recipients, but were not as protective as enriched immune T cells or B cells. The results obtained in adoptive transfer experiments using phagocytic cells from the spleen of immune mice depended on the length of time spleen cells were incubated in petri-dishes at 37° C before harvesting the phagocytes. Using C57B1 mice, phagocytes harvested after 15 hours incubation were as protective as unfractionated immune cells in a cell transfer experiment, but phagocytes harvested after 16 hours incubation were not protective. Examination of NIH phagocytic cells after 2.5 hours incubation at 37°C, which were as protective as unfractionated immune spleen cells in a cell transfer experiment, demonstrated that the petri-dish adherent cells may have contained B lymphocytes. c) The passive transfer of immunity with serum from P.chabaudi infected mice. The passive transfer of serum from C57B1 mice which had been previously infected with P.chabaudi to normal or irradiated syngeneic mice demonstrated that the serum recipients were initially protected from infection. Irradiated mice, however, were delayed longer in the onset of parasitaemia compared to non-irradiated mice. Using NIH mice, sera were collected from unfractionated immune spleen cell recipients, enriched immune T cell recipients and normal spleen recipients on the 11th day of a P.chabaudi infection, just after peak parasitaemia, and also on the 14th day of infection. On day 14, all immune cells recipients and most of the enriched immune T cell recipients had become subpatent but all normal cell recipients still had patent infections. Sera collected from the different spleen cell recipients on the 11th day of infection and passively transferred to irradiated mice demonstrated little protection. Sera collected on the 14th day of infect ion, however, reflected the immune status of the donors in their protective properties in mice infected with P.chabaudi. The serum from unfractionated immune cell recipients was the most protective of the 3 sera when compared to normal NIH serum and the serum from enriched immune T cell recipients was slightly protective, but the serum from normal cell recipients produced an enhanced infection in mice infected with P.chabaudi. d) Antibody-dependent cell-mediated cytotoxicity of spleen cells in P.chabaudi infected mice. In a preliminary investigation of K cell activity in the spleens of P.chabaudi infected mice, it was found that there was an increased activity of K cells collected at around peak parasitaemia compared to the activity of K cells in non-infected mice, and that this increased activity could also be found in mice which had recently become subpatent. As the target cell for antibody-dependent cell-mediated cytotoxicity employed was the thick red blood cell, it is not known whether the K cell is involved in the killing of P.chabaudi parasites. These results suggest that both T cells and B cells and antibody may be important in the immune response to P.chabaudi in mice. Primed T cells may act as helper cells in the production of malarial antibodies, but, as enriched primed T cells could confer protection on immunodepressed mice, it is possible that a cell-mediated mechanism of immunity may also exist.