A manipulative study of macroinvertebrate grazers in Hong Kong streams: do snails compete with insects?

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The G5 domain: a potential N-acetylglucosamine recognition domain involved in biofilm formation

SUMMARY: Biofilms are complex microbial communities found at surfaces that are often associated with extracellular polysaccharides. Biofilm formation is a complex process that is being understood at the molecular level only recently. We have identified a novel domain that we call the G5 domain (named after its conserved glycine residues), which is found in a variety of enzymes such as Streptococcal IgA peptidases and various glycosyl hydrolases in bacteria. The G5 domain is found in the Accumulation Associated Protein (AAP), which is an important component in biofilm formation in Staphylococcus aureus. A common feature of the proteins containing G5 domains is N-acetylglucosamine binding, and we attribute this function to the G5 domain. CONTACT: agb@sanger.ac.uk.     

NetLogoR: a package to build and run spatially explicit agent‐based models in R

NetLogoR is an R package to build and run spatially explicit agent‐based models (SE‐ABMs) using the R language. SE‐ABMs are models that simulate the fate of entities at the individual level within a spatial context and where patterns emerge at the population level. NetLogoR follows the same framework as the NetLogo software (Wilensky 1999). Rather than a call function to use the NetLogo software, NetLogoR is a translation into the R language of the structure and functions of NetLogo. Models built with NetLogoR are written in R language and are run on the R platform; no other software or language has to be involved. NetLogoR provides new R classes to define model agent objects and functions to implement spatially explicit agent‐based models in the R environment. Users of this package benefit from the fast and easy coding provided by the highly developed NetLogo framework, coupled with the versatility, power and massive resources of the R language.     

Liquid chromatographic assays for DE-310, a novel camptothecin analog, and two major enzymatic products in human matrices

Assays were developed for determination of DE-310, a carboxymethyldextran polyalcohol conjugate of the topoisomerase I inhibitor DX-8951 (exatecan) and two enzymatic products (i.e. glycyl-DX-8951 and unconjugated DX-8951) in human whole blood, erythrocytes and saliva. Sample pretreatment involved a single protein-precipitation step, followed by a thermolysin-mediated deconjugation for the parent molecule. Separation of the compounds was achieved on an Inertsil ODS-80A column (150 mm x 4.6 mm i.d.; 5 microm PS), using isocratic elution. The column effluent was monitored at excitation and emission wavelengths of 375 and 445 nm, respectively. Validation results indicated that the methods are accurate and precise at lower limits of quantitation of 0.5-6.9 ng/ml. The methods were used to study the blood distribution and salivary concentrations in patients receiving DE-310.     

Predictors of Beta-Blocker Intolerance and Mortality in Patients After Acute Coronary Syndrome

Purpose

To investigate the predictors of intolerance to beta-blockers treatment and the 6-month mortality in hospitalized patients with acute coronary syndrome (ACS).

Methods

This was a single-center, prospective, and longitudinal study including 370 consecutive ACS patients in Killip class I or II. BBs were prescribed according to international guidelines and withdrawn if intolerance occurred. The study was approved by the institutional ethics committee of our university. Statistics: the clinical parameters evaluated at admission, and the related intolerance to BBs and death at 6 months were analyzed using logistic regression (p<0.05)in PATIENTS.

Results

BB intolerance was observed in 84 patients and was associated with no prior use of statins (OR: 2.16, 95%CI: 1.26–3.69, p= 0.005) and Killip class II (OR: 2.5, 95%CI: 1.30-4.75, p=0.004) in the model adjusted for age, sex, blood pressure, and renal function. There was no association with ST-segment alteration or left anterior descending coronary artery plaque. Intolerance to BB was associated with the greatest risk of death (OR: 4.5, 95%CI: 2.15–9.40, p<0.001).

Conclusions

After ACS, intolerance to BBs in the first 48 h of admission was associated to non previous use of statin and Killip class II and had a high risk of death within 6 months.     

Respiratory heat loss of Holstein cows in a tropical environment

In order to develop statistical models to predict respiratory heat loss in dairy cattle using simple physiological and environmental measurements, 15 Holstein cows were observed under field conditions in a tropical environment, in which the air temperature reached up to 40°C. The measurements of latent and sensible heat loss from the respiratory tract of the animals were made by using a respiratory mask. The results showed that under air temperatures between 10 and 35°C sensible heat loss by convection decreased from 8.24 to 1.09 W m^–2, while the latent heat loss by evaporation increased from 1.03 to 56.51 W m^–2. The evaporation increased together with the air temperature in almost a linear fashion until 20°C, but it became increasingly high as the air temperature rose above 25°C. Convection was a mechanism of minor importance for respiratory heat transfer. In contrast, respiratory evaporation was an effective means of thermoregulation for Holsteins in a hot environment. Mathematical models were developed to predict both the sensible and latent heat loss from the respiratory tract in Holstein cows under field conditions, based on measurements of the ambient temperature, and other models were developed to predict respiration rate, tidal volume, mass flow rate and expired air temperature as functions of the ambient temperature and other variables.This paper forms part of A. S. Campos Maias doctoral thesis.     

Participation and Contribution in Crowdsourced Surveys

This paper identifies trends within and relationships between the amount of participation and the quality of contributions in three crowdsourced surveys. Participants were asked to perform a collective problem solving task that lacked any explicit incentive: they were instructed not only to respond to survey questions but also to pose new questions that they thought might-if responded to by others-predict an outcome variable of interest to them. While the three surveys had very different outcome variables, target audiences, methods of advertisement, and lengths of deployment, we found very similar patterns of collective behavior. In particular, we found that: the rate at which participants submitted new survey questions followed a heavy-tailed distribution; the distribution in the types of questions posed was similar; and many users posed non-obvious yet predictive questions. By analyzing responses to questions that contained a built-in range of valid response we found that less than 0.2% of responses lay outside of those ranges, indicating that most participants tend to respond honestly to surveys of this form, even without explicit incentives for honesty. While we did not find a significant relationship between the quantity of participation and the quality of contribution for both response submissions and question submissions, we did find several other more nuanced participant behavior patterns, which did correlate with contribution in one of the three surveys. We conclude that there exists an optimal time for users to pose questions early on in their participation, but only after they have submitted a few responses to other questions. This suggests that future crowdsourced surveys may attract more predictive questions by prompting users to pose new questions at specific times during their participation and limiting question submission at non-optimal times.