Competing cognitive pressures on human exploration in the absence of trade-off with exploitation

Exploring novel environments through sequential sampling is essential for efficient decision-making under uncertainty. In the laboratory, human exploration has been studied in situations where exploration is traded against reward maximisation. By design, these ‘explore-exploit’ dilemmas confound the behavioural characteristics of exploration with those of the trade-off itself. Here we designed a sequential sampling task where exploration can be studied and compared in the presence and absence of trade-off with exploitation. Detailed model-based analyses of choice behaviour revealed specific exploration patterns arising in situations where information seeking is not traded against reward seeking. Human choices are directed toward the most uncertain option available, but only after an initial sampling phase consisting of choice streaks from each novel option. These findings outline competing cognitive pressures on information seeking: the repeated sampling of the current option (for hypothesis testing), and the directed sampling of the most uncertain option available (for structure mapping).

Assessment of Gypsum as a Soil Ameliorant on Salt-affected Soils in the Ho-Keta Plain of the Volta Region, Ghana

Aims: To assess the effectiveness of Gypsum as a chemical ameliorant on three selected salt-affected soils of the Ho-Keta plain, in the Volta region of Ghana. Study Design: Complete Randomized Design. Place and Duration of Study: Soil Research Institute, Kwadaso, Kumasi between June 2014 and July 2019. Methodology: Soil sampling was taken in two forms. The initial sampling was taken at a depth of 0-30 cm from Anyako, Anyenui and Atiehife for the soil physical and chemical analysis. Samples were further taken from profiles, composited and sub-sampled for the leaching experiment. Approximately 2.6 kg of the soil samples from the different sites were taken, mixed thoroughly with different rates 0%, 25%, 50%, 75% and 100% of Gypsum, (CaSO4.2H2O) and filled into fifteen perforated polyvinyl plastic pots and replicated four times. The pots were saturated with water, incubated for 24 h and leached intermittently with 120 mL distilled water for a period of four weeks. Results: Significant displacement of Na+ by Ca2+ and subsequently leached became evident in the reduced values recorded for pH, EC and SAR. The applied gypsum reduced pH within a range of 4.0 to 4.2 compared to the original soil with no significant differences among the treatments at p = 0.05. Though a similar trend was observed for EC, significant difference at p = 0.05 was observed at gypsum level above 50%. Sodium adsorption ratio recorded a marked difference as gypsum level was varied with significant difference at p = 0.05 compare to the control. Conclusion: The study revealed that gypsum rates at 75% and 100% Gypsum requirement were effective in improving the chemical properties of the soils with significant reductions in salinity, sodicity and pH. Atiehife soil performed better compared to Anyenui and Anyako soils.

Mediastinal Nodular Lymphocyte Predominant Hodgkin Lymphoma Achieved by Endoscopic Transesophageal Cryobiopsy

Guidelines have recommended endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) and endoscopic ultrasound-guided fine-needle aspiration biopsy as initial sampling approaches of mediastinal lymph nodes for lung cancer staging. However, the small sample volume might restrict the diagnostic utility of needle aspiration in certain mediastinal diseases. We have recently shown that transbronchial mediastinal cryobiopsy, which is capable of providing larger amounts of intact tissue, improves diagnostic yield in rare tumors and benign diseases compared to EBUS-TBNA. Here, we present a case of mediastinal nodular lymphocyte predominant Hodgkin lymphoma successfully diagnosed by endoscopic transesophageal cryobiopsy.

Data and Diversity Driven Development of a Shotgun Crystallisation Screen using the Protein Data Bank

Protein crystallisation has for decades been a critical and restrictive step in macromolecular structure determination via X-ray diffraction. Crystallisation typically involves a multi-stage exploration of the available chemical space, beginning with an initial sampling (screening) followed by iterative refinement (optimisation). Effective screening is important for reducing the number of optimisation rounds required, reducing the cost and time required to determine a structure. Here, we propose an initial screen (Shotgun II) derived from analysis of the up-to-date Protein Data Bank (PDB) and compare it with the previously derived (2014) Shotgun I screen. In an update to that analysis, we clarify that the Shotgun approach entails finding the crystallisation conditions which cover the most diverse space of proteins by sequence found in the PDB - which can be mapped to the well known Maximum Coverage problem in computer science. With this realisation we are able to apply a more effective algorithm for selecting conditions, such that the Shotgun II screen outperforms the Shotgun I screen both in protein coverage and quantity of data input. Our data demonstrates that the Shotgun I screen, compared with alternatives, has been remarkably successful over the seven years it has been in use, indicating that Shotgun II is likely to be a highly effective screen.

EXPRESS: Paired Sensitivity Analysis of Four SARS-CoV-2 Serological Immunoassays in a Longitudinal Cohort of Convalescent Hospital Staff

BACKGROUND: SARS-CoV-2 serological testing has seen extensive academic and clinical use from investigating correlates of immunity to seroprevalence, convalescent plasma and vaccine trials. Interpretation of these studies will depend on robust validation of the longitudinal sensitivities of these assays, especially in the context of mild disease which makes up the majority of the Coronavirus Disease 2019 (COVID-19) caseload. METHODS: Hospital staff (n=94) returning to work following polymerase chain reaction (PCR) confirmed COVID-19 were offered antibody testing to assist with laboratory verification. Initial specimens were collected at median 29 days post-symptom onset and run on the Roche, Abbott, Siemens and DiaSorin platforms. Re-sampling occurred at median 142 days from a subset of the initial cohort (n=62) that had volunteered to provide further sera to assist in longitudinal sensitivity analysis. Samples that were not run across all four platforms were excluded from analysis. RESULTS: Comparative sensitivity analysis was conducted on 89/94 of the initial specimens and 55/62 of the repeat specimens. Sensitivity at initial sampling ranged from 78-87% across platforms. At re-sampling, sensitivities were: 100% (Roche), 45% (Abbott), 100% (Siemens), and 80% (DiaSorin). Paired analysis using the longitudinal cohort (n=55) demonstrated stable or increasing median assay values on three platforms, with a clear reduction seen only on the Abbott platform (4.78 to 1.34) with corresponding sensitivity drop-off (81.8% to 45.4%). CONCLUSION: The Abbott assay demonstrated sensitivity drop-off and decrease in median assay signal below detection threshold at 4-5 months. This has implications on the interpretation and design of future studies.

SARS-CoV-2 Infections and Viral Isolations among Serially Tested Cats and Dogs in Households with Infected Owners in Texas, USA

Understanding the ecological and epidemiological roles of pets in the transmission of SARS-CoV-2 is critical for animal and human health, identifying household reservoirs, and predicting the potential enzootic maintenance of the virus. We conducted a longitudinal household transmission study of 76 dogs and cats living with at least one SARS-CoV-2-infected human in Texas and found that 17 pets from 25.6% of 39 households met the national case definition for SARS-CoV-2 infections in animals. This includes three out of seventeen (17.6%) cats and one out of fifty-nine (1.7%) dogs that were positive by RT-PCR and sequencing, with the virus successfully isolated from the respiratory swabs of one cat and one dog. Whole-genome sequences of SARS-CoV-2 obtained from all four PCR-positive animals were unique variants grouping with genomes circulating among people with COVID-19 in Texas. Re-sampling showed persistence of viral RNA for at least 25 d-post initial test. Additionally, seven out of sixteen (43.8%) cats and seven out of fifty-nine (11.9%) dogs harbored SARS-CoV-2 neutralizing antibodies upon initial sampling, with relatively stable or increasing titers over the 2–3 months of follow-up and no evidence of seroreversion. The majority (82.4%) of infected pets were asymptomatic. ‘Reverse zoonotic’ transmission of SARS-CoV-2 from infected people to animals may occur more frequently than recognized.

Sources and pathways of biocides and their transformation products in 2ha urban district

<p>Biocides used as film protection products to prevent algae and fungi growth on facades wash off during rain events and represent a potential risk to the environment. So far, urban monitoring studies focused mainly on large heterogeneous urban areas. Thus, little information about individual sources and entry pathways were obtained. However, this is important to understand the potential risk of biocide entry to groundwater.</p><p>This study investigates biocide emissions from a 2 ha residential area, 13 years after construction has ended. Investigated substances represent commonly used biocides for film protection, i.e. Terbutryn, Diuron and Octylisothiazolinone (OIT) and some of their known transformation products (TPs, Diuron-Desmethyl, Terbumeton, 2-Hydroxy-Terbutylazin and Terbutryn-Desethyl). We used existing urban infrastructure for efficient monitoring and applied a three-step approach to (a) determine the overall relevance of biocides, (b) identify source areas and long-term emission and (c) characterize entry pathways into surface- and groundwater.</p><p>Initial sampling in the swale system gave an integrated signal from the entire district and confirmed the relevance of biocide leaching, more than a decade after construction. Concentrations peaked at 174 ng/L for Diuron and 40 ng/L for Terbutryn during a high magnitude event and were above PNEC values. During later events, transformation products were detected, though at lower concentrations. For all substances, source areas were identified in a second step. Artificial elution experiments confirmed expected sources, i.e. façades, but we also found additional sources through sampling of rainfall downpipes from flat roofs. A small part of the roof façade was repainted two years before sampling and thereby showed a magnitude higher leaching rates than the remaining façades. Since all biocide wash-off arrived on a flat roof and was drained by rainfall down pipes, we could estimate net biocide emission and arrived at 155 mg Diuron, 17 mg Terbutryn, 12 mg OIT and 17 mg Diuron-Desmethyl from a 10 m<sup>2</sup> painted façade area over a time period of two years. In a third step, we characterized entry pathways comparing samples from a drainage pipe that collected road runoff (surface pathway) with two others that collected infiltrated water on top of an underground garage (soil pathway). All drainage pipes showed Terbutryn, two of them also Diuron but none OIT. The drainage pipe representing the surface pathway showed a smaller number of individual transformation products but similar concentrations of parent compounds. One pipe representing the soil pathway had highest concentrations of Terbutryn and its TPs which suggests a high leaching potential of this biocide also away from concentrated infiltration in urban stormwater management infrastructure.</p>

Have Sustained Acidic Deposition Decreases Led to Increased Calcium Availability in Recovering Watersheds of the Adirondack Region of New York, USA?

Soil calcium depletion has been strongly linked to acidic deposition in eastern North America and recent studies have begun to document the recovery of soils in response to large decreases in acidic deposition. However, increased calcium availability has not yet been seen in the B horizon, where calcium depletion has been most acute, but mineral weathering is critically important for resupplying ecosystem calcium. This study provides new data in seven watersheds in the Adirondack region (New York, USA), where acidic deposition impacts on soils and surface waters have been substantial and recovery remains slow. Initial sampling in 1997–1998 and 2003–2004 was repeated in 2009–2010, 2014, 2016 and 2017. Exchangeable calcium concentrations increased by an average of 43% in the Oe horizon of three watersheds where this horizon was sampled (10.7–15.3 cmolc kg−1). Changes in calcium were not seen in the individual watersheds of the Oa and B horizons, but as a group, a significant increase in calcium was measured in the upper B horizon. Liming of a calcium-depleted watershed also tripled calcium concentration in the upper B horizon in 5 years. However, stream calcium in unlimed watersheds decreased over the study period. Small increases in B-horizon calcium may be underway.

Fault network reconstruction using agglomerative clustering: applications to southern Californian seismicity

In this paper we introduce a method for fault network reconstruction based on the 3D spatial distribution of seismicity. One of the major drawbacks of statistical earthquake models is their inability to account for the highly anisotropic distribution of seismicity. Fault reconstruction has been proposed as a pattern recognition method aiming to extract this structural information from seismicity catalogs. Current methods start from simple large-scale models and gradually increase the complexity trying to explain the small-scale features. In contrast the method introduced here uses a bottom-up approach that relies on initial sampling of the small-scale features and reduction of this complexity by optimal local merging of substructures. First, we describe the implementation of the method through illustrative synthetic examples. We then apply the method to the probabilistic absolute hypocenter catalog KaKiOS-16, which contains three decades of southern Californian seismicity. To reduce data size and increase computation efficiency, the new approach builds upon the previously introduced catalog condensation method that exploits the heterogeneity of the hypocenter uncertainties. We validate the obtained fault network through a pseudo prospective spatial forecast test and discuss possible improvements for future studies. The performance of the presented methodology attests to the importance of the non-linear techniques used to quantify location uncertainty information, which is a crucial input for the large-scale application of the method. We envision that the results of this study can be used to construct improved models for the spatiotemporal evolution of seismicity.