The Effects of Abstraction on Best NBlock First Search

Search is an important aspect of Artificial Intelligence and many advances have been achieved in finding optimal solutions for a variety of search problems. Up until recently most search problems were solved using a serial-single threaded approach. Speed is extremely important and one way to decrease the amount of time needed to find a solution is to use better hardware. A single threaded approach is limited in this way because newer processors are not much faster than previous generations. Instead industry has added more cores to allow more threads to work at the same time. In order to solve this limitation and take advantage of newer multi-core processors, many parallel approaches have been developed. The best approach to parallel search is an algorithm named Parallel Best-N Block First Search (PBNF). PBNF relies on an abstraction function to divide up the work in a way that allows threads to work efficiently with little contention. This thesis studies the way this abstraction function chooses to build the abstraction and demonstrates that better abstractions can be built. This abstraction focuses on goal variables on ways to keep the number of abstract states as small as possible while adding as many variables as feasible

Computer Programs for Calculating and Plotting the Stability Characteristics of a Balloon Tethered in a Wind

Computer programs for calculating the stability characteristics of a balloon tethered in a steady wind are presented. Equilibrium conditions, characteristic roots, and modal ratios are calculated for a range of discrete values of velocity for a fixed tether-line length. Separate programs are used: (1) to calculate longitudinal stability characteristics, (2) to calculate lateral stability characteristics, (3) to plot the characteristic roots versus velocity, (4) to plot the characteristic roots in root-locus form, (5) to plot the longitudinal modes of motion, and (6) to plot the lateral modes for motion. The basic equations, program listings, and the input and output data for sample cases are presented, with a brief discussion of the overall operation and limitations. The programs are based on a linearized, stability-derivative type of analysis, including balloon aerodynamics, apparent mass, buoyancy effects, and static forces which result from the tether line

An Accounting International Experience Course

Accounting students need practical opportunities to personally experience other cultures and international business practices if they are to effectively compete in today’s global marketplace.  In order to address this need, the Department of Accounting at Murray State University offers an international experience course which includes a short-term study tour of London.  This paper examines the rationale for an accounting international experience course, provides an overview of the class and presents a suggested itinerary for the London trip

New insights into the evolutionary rate of HIV-1 at the within-host and epidemiological levels

Over calendar time, HIV-1 evolves considerably faster within individuals than it does at the epidemic level. This is a surprising observation since, from basic population genetic theory, we would expect the genetic substitution rate to be similar across different levels of biological organization. Three different mechanisms could potentially cause the observed mismatch in phylogenetic rates of divergence: temporal changes in selection pressure during the course of infection; frequent reversion of adaptive mutations after transmission; and the storage of the virus in the body followed by the preferential transmission of stored ancestral virus. We evaluate each of these mechanisms to determine whether they are likely to make a major contribution to the mismatch in phylogenetic rates. We conclude that the cycling of the virus through very long-lived memory CD4+ T cells, a process that we call ‘store and retrieve’, is probably the major contributing factor to the rate mismatch. The preferential transmission of ancestral virus needs to be integrated into evolutionary models if we are to accurately predict the evolution of immune escape, drug resistance and virulence in HIV-1 at the population level. Moreover, early infection viruses should be the major target for vaccine design, because these are the viral strains primarily involved in transmission

cAMP Control of HCN2 Channel Mg2+ Block Reveals Loose Coupling between the Cyclic Nucleotide-Gating Ring and the Pore

Hyperpolarization-activated cyclic nucleotide-regulated HCN channels underlie the Na+-K+ permeable IH pacemaker current. As with other voltage-gated members of the 6-transmembrane KV channel superfamily, opening of HCN channels involves dilation of a helical bundle formed by the intracellular ends of S6 albeit this is promoted by inward, not outward, displacement of S4. Direct agonist binding to a ring of cyclic nucleotide-binding sites, one of which lies immediately distal to each S6 helix, imparts cAMP sensitivity to HCN channel opening. At depolarized potentials, HCN channels are further modulated by intracellular Mg2+ which blocks the open channel pore and blunts the inhibitory effect of outward K+ flux. Here, we show that cAMP binding to the gating ring enhances not only channel opening but also the kinetics of Mg2+ block. A combination of experimental and simulation studies demonstrates that agonist acceleration of block is mediated via acceleration of the blocking reaction itself rather than as a secondary consequence of the cAMP enhancement of channel opening. These results suggest that the activation status of the gating ring and the open state of the pore are not coupled in an obligate manner (as required by the often invoked Monod-Wyman-Changeux allosteric model) but couple more loosely (as envisioned in a modular model of protein activation). Importantly, the emergence of second messenger sensitivity of open channel rectification suggests that loose coupling may have an unexpected consequence: it may endow these erstwhile “slow” channels with an ability to exert voltage and ligand-modulated control over cellular excitability on the fastest of physiologically relevant time scales

Cotrimoxazole for childhood febrile illness in Malaria-endemic regions

The efficacy of co-trimoxozole for the treatment of Plasmodium falciparum parasitaemia in children younger than 5 years of age was evaluated in Malawi. 46 children with P. falciparum parasitaemia, 37% of whom also met clinical criteria for a diagnosis of acute lower respiratory tract infection, were treated with 20 mglkg co-trimoxazole twice daily for five days. Parasitaemia (mean clearance time 2.7 days) and symptoms were rapidly abolished and improvement was maintained during follow-up for 14 days. Co-trimoxazole may be an effective single treatment for febrile illness in young children in areas where malaria is endemic, resources are few, and diagnosis must rely on clinical findings alone

High-Risk Environmental Conditions Attenuates Performance Efficiency Index in NCAA DI Female Soccer Players

International Journal of Exercise Science 15(6): 442-454, 2022. The purpose of this study was to evaluate the effects of environmental conditions on running performance and performance efficiency index (Effindex). Performance data recorded using Polar Team Pro sensors from eight collegiate female soccer players in nine matches were analyzed during the 2019 competitive season. Effindex and running performance, including total distance covered (TDREL) and distance covered in five speed thresholds relative to minutes played, were examined for indications of fatigue with respect to environmental conditions, including ambient temperature and relative humidity. Matches were separated into three groups based on environmental conditions: Low-Risk (n = 2 matches), Moderate-Risk (n = 3 matches), or High-Risk (n = 4 matches). Speed thresholds were grouped as follows: walking (WALKREL), jogging (JOGREL), low-speed running (LSRREL), high-speed running (HSRREL), and sprinting (SPRINTREL). A significant effect was observed for TDREL in all environmental conditions (η2 = 0.614). TDREL was significantly lower in the High-Risk (p = 0.002; 95.32 ± 12.04 m/min) and Moderate-Risk conditions (p = 0.004; 94.85 ± 9.94 m/min) when compared to Low-Risk (105.61 ± 9.95 m/min). WALKREL (p = 0.005), JOGREL (p = 0.005) LSRREL (p = 0.001), HSRREL (p = 0.035), SPRINTREL (p = 0.017), and Effindex (p = 0.0004) were significantly greater in Low-Risk conditions when compared to Moderate-Risk conditions. WALKREL (p = 0.005), HSRREL (p = 0.029), SPRINTREL (p = 0.005), and Effindex (p = 0.0004) were significantly greater in Low-Risk conditions when compared to High-Risk conditions. High-Risk environmental conditions may result in adverse performance in female collegiate soccer players

Report 14: Online community involvement in COVID-19 research & outbreak response: early insights from a UK perspective

The Patient Experience Research Centre (PERC) at Imperial College London is developing research to explore and understand people’s views about, experiences of and behavioural responses to the outbreak in the UK and elsewhere. To guide that effort and to help inform COVID-19 research and responses more broadly - for example in mathematical modelling and policy - PERC launched an online community involvement initiative that sought rapid, early insight from members of the public and aimed to establish a network for ongoing community engagement. Priority areas for COVID-19 research Vaccine development was considered the most urgent research priority for many respondents. Social studies exploring the public’s experiences, risk perceptions and behaviours during this outbreak were necessary and important according to 95% of the respondents. Such research could: Improve the way the current outbreak response is planned and implemented; Improve the way information and guidance is provided to and understood by the public; Optimise the support provided to communities and vulnerable groups; and Improve future outbreak preparedness. Other recommended areas of research included: Understanding the role of the media in influencing how people react and respond; Furthering our basic understanding of the virus – how it spreads, who it affects the most and why, and whether people achieve and maintain immunity after being infected; Critiquing the UK’s response to the pandemic against that of other countries; and Ensuring lessons can be learnt from this outbreak to better equip us for future outbreaks, and public health emergencies in general. Key unmet needs amongst communities The main challenges described by respondents were ineffective communication, including access to information and information overload; and conflicting guidance and misinformation. Respondents’ described feelings of concern, confusion and, in some cases, panic as a result of these communication and information challenges. Others shared their frustration that there was nowhere to post their concerns or questions. In addition, respondents expressed a need for more detailed and bespoke practical guidance about their risk and how best to prepare and protect themselves and their loved ones. Almost half (47%) wanted to hear about the latest research on the virus, and 45% wanted a dedicated internet portal where they could access the latest information and trusted guidance. Making information more accessible to different communities, including those who are not online and those who have English as a second language was also highlighted as a priority