On Steering Swarms

The main contribution of this paper is a novel method allowing an external observer/controller to steer and guide swarms of identical and indistinguishable agents, in spite of the agents' lack of information on absolute location and orientation. Importantly, this is done via simple global broadcast signals, based on the observed average swarm location, with no need to send control signals to any specific agent in the swarm

Chemical concentration map building through bacterial foraging optimization based search algorithm by mobile robots

In this article we present implementation of Bacterial Foraging Optimization algorithm inspired search by multiple robots in an unknown area in order to find the region with highest chemical gas concentration as well as to build the chemical gas concentration map. The searching and map building tasks are accomplished by using mobile robots equipped with smart transducers for gas sensing called "KheNose". Robots perform the search autonomously via bacterial chemotactic behavior. Moreover, simultaneously the robots send their sensor readings of the chemical concentration and their position data to a remote computer (a base station), where the data is combined, interpolated, and filtered to form an real-time map of the chemical gas concentration in the environment. ©2010 IEEE

An assessment of vulnerability to HIV infection of boatmen in Teknaf, Bangladesh

<p>Abstract</p> <p>Background</p> <p>Mobile population groups are at high risk for contracting HIV infection. Many factors contribute to this risk including high prevalence of risky behavior and increased risk of violence due to conflict and war. The Naf River serves as the primary border crossing point between Teknaf, Bangladesh and Mynamar [Burma] for both official and unofficial travel of people and goods. Little is known about the risk behavior of boatmen who travel back and forth between Teknaf and Myanmar. However, we hypothesize that boatmen may act as a bridging population for HIV/AIDS between the high-prevalence country of Myanmar and the low-prevalence country of Bangladesh.</p> <p>Methods</p> <p>Methods included initial rapport building with community members, mapping of boatmen communities, and in-depth qualitative interviews with key informants and members from other vulnerable groups such as spouses of boatmen, commercial female sex workers, and injecting drug users. Information from the first three stages was used to create a cross-sectional survey that was administered to 433 boatmen.</p> <p>Results</p> <p>Over 40% of the boatmen had visited Myanmar during the course of their work. 17% of these boatmen had sex with CSW while abroad. There was a significant correlation found between the number of nights spent in Myanmar and sex with commercial sex workers.</p> <p>In the past year, 19% of all boatmen surveyed had sex with another man. 14% of boatmen had participated in group sex, with groups ranging in size from three to fourteen people. Condom use was rare {0 to 4.7% during the last month}, irrespective of types of sex partners. Regression analysis showed that boatmen who were 25 years and older were statistically less likely to have sexual intercourse with non- marital female partners in the last year compared to the boatmen aged less than 25 years. Similarly deep-sea fishing boatmen and non-fishing boatmen were statistically less likely to have sexual intercourse with non- marital female partners in the last year compared to the day long fishing boatmen adjusting for all other variables. Boatmen's knowledge regarding HIV transmission and personal risk perception for contracting HIV was low.</p> <p>Conclusion</p> <p>Boatmen in Teknaf are an integral part of a high-risk sexual behaviour network between Myanmar and Bangladesh. They are at risk of obtaining HIV infection due to cross border mobility and unsafe sexual practices. There is an urgent need for designing interventions targeting boatmen in Teknaf to combat an impending epidemic of HIV among this group. They could be included in the serological surveillance as a vulnerable group. Interventions need to address issues on both sides of the border, other vulnerable groups, and refugees. Strong political will and cross border collaboration is mandatory for such interventions.</p

Depletion depth studies with the MALTA2 sensor, a depleted monolithic active pixel sensor

MALTA2 is a depleted monolithic active pixel sensor (DMAPS) developed in the Tower 180 nm CMOS imaging process. Monolithic CMOS sensors offer advantages over current hybrid imaging sensors both in terms of increased tracking performance due to lower material budget but also in terms of ease of integration and construction costs due to the monolithic design. Current research and development efforts are aimed towards radiation-hard designs up to 100 Mrad in Total Ionizing Dose and 3 × 1015 1 MeV neq / cm2 in Non-Ionizing Energy Loss. One important property of a sensor’s radiation hardness is the depletion depth at which efficient charge collection is achieved via drift movement. Grazing angle test-beam data was taken during the 2023 SPS CERN test beam with the MALTA telescope and Edge Transient Current Technique studies were performed at DESY in order to develop a quantitative study of the depletion depth for un-irradiated, epitaxial MALTA2 samples. The study is planned to be extended for irradiated and Czochralski MALTA2 samples

Probing the action of a novel anti-leukaemic drug therapy at the single cell level using modern vibrational spectroscopy techniques

Acute myeloid leukaemia (AML) is a life threatening cancer for which there is an urgent clinical need for novel therapeutic approaches. A redeployed drug combination of bezafibrate and medroxyprogesterone acetate (BaP) has shown anti-leukaemic activity in vitro and in vivo. Elucidation of the BaP mechanism of action is required in order to understand how to maximise the clinical benefit. Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Synchrotron radiation FTIR (S-FTIR) and Raman microspectroscopy are powerful complementary techniques which were employed to probe the biochemical composition of two AML cell lines in the presence and absence of BaP. Analysis was performed on single living cells along with dehydrated and fixed cells to provide a large and detailed data set. A consideration of the main spectral differences in conjunction with multivariate statistical analysis reveals a significant change to the cellular lipid composition with drug treatment; furthermore, this response is not caused by cell apoptosis. No change to the DNA of either cell line was observed suggesting this combination therapy primarily targets lipid biosynthesis or effects bioactive lipids that activate specific signalling pathways