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Subjects learned to classify images of rocks into the categories igneous, metamorphic, and sedimentary. In accord with the real-world structure of these categories, the to-be-classified rocks in the experiments had a dispersed similarity structure. Our central hypothesis was that learning of these complex categories would be improved through observational study of organized, simultaneous displays of the multiple rock tokens. In support of this hypothesis, a technique that included the presentation of the simultaneous displays during phases of the learning process yielded improved acquisition (Experiment 1 ) and generalization (Experiment 2 ) compared to methods that relied solely on sequential forms of study and testing. The technique appears to provide a good starting point for application of cognitive-psychology principles of effective category learning to the science classroom.

Captive rearing is a common practice for the stocking, conservation, and supplementation of fish species worldwide, but captive‐reared fish can exhibit altered phenotypes leading to reduced fitness in nature compared to wild conspecifics. In salmonids, certain studies have found limited genetic differentiation between wild and captive‐reared fish. However, documented changes in gene expression in hatchery fish have led scientists to investigate epigenetic mechanisms, such as DNA methylation, as a source of these differences. In this binational collaborative piece, we synthesize the knowledge and efforts of academics and government scientists to highlight how interactions between captive rearing and the epigenome elicit parallel phenotypic changes across salmonid species. We examine the known and potential links between DNA methylation and the phenotypic effects of captive rearing including changes in behavior, color, gut microbiomes, and developmental abnormalities. We review efforts to minimize these phenotypic and epigenetic effects including attempts to modify the hatchery environment and rearing protocols. We provide a framework to integrate epigenetic considerations into hatchery rearing protocols by weighing the heritable nature of DNA methylation with the goals of different captive rearing programs and explore whether minimizing the phenotypic and epigenetic effects of captive rearing is worthwhile. We examine heritability and persistence of epigenetic effects, and we propose the exploitation of heritable bet‐hedging as an epigenetic buffer to increase post‐release survival. We also suggest novel applications of epigenomic biomarkers as a non‐lethal method for post‐release monitoring. Ultimately, collaborative multi‐disciplinary research across species is needed to understand the comprehensive effects of captive rearing, reduce the ecological impacts of captive fish in the wild, and increase population resilience. Integrating epigenetics into fish hatchery management will provide new opportunities for optimizing and improving captive rearing.

The affiliation for Dr. Paulo F. Carvalho is listed incorrectly in this paper, The correct affiliation is Carnegie Mellon University, Pittsburgh, PA, USA.The affiliation for Dr. Paulo F. Carvalho is listed incorrectly in this paper, The correct affiliation is Carnegie Mellon University, Pittsburgh, PA, USA.

A highly controlled laboratory experiment was conducted that suggested computer-based image training of rock classifications can provide a useful supplement to physical rock training. Two groups of participants learned to classify samples of 12 major types of rocks during a training phase. One group was trained using computer images of the rock samples, and another group was trained with physical rock samples. A third group that was familiarized with images of the samples but did not receive initial classification training served as a control. The participants' ability to generalize their training to the classification of novel, physical rock samples from the 12 types was then assessed in a test phase. All groups received trial-by-trial feedback during this test phase; still, the image-based and physical rock training groups maintained a significant performance advantage (75.2% correct) compared to the control group (37.5% correct). The group that received physical rock training performed only slightly better overall (77.8% correct) than the image-based training group (72.5% correct), although the advantage for the physical rock training group was substantial for some specific types of rocks from the complete set. The results provide documentation for the potential benefits of using image-based classification-training methods as a means of supplementing physical rock classification-training methods.

Categorization and old-new recognition memory are closely linked topics in the psychological literature, and have both benefitted from extensive formal modelling efforts. However, the existing literature examining their relationship has almost exclusively used simplified artificial stimuli. The present work extends this literature by collecting both categorization and old-new recognition judgments on a set of naturalistic stimuli: namely, a set of 540 images of rocks. The abilities of different models to fit the categorization and recognition data are discussed in detail, as are various efforts at improving the feature space representation of the stimuli. Ultimately, the categorization data was fit well by an exemplar and clustering model, but not a prototype model. Only the exemplar model was able to provide an account of the recognition data; however, the model had difficulty capturing variability in participants’ recognition judgments of previously seen stimuli.

In angiosperms the late pollen actins (LPAs) are strongly expressed in mature pollen and pollen tubes and at much lower levels in ovules. Four Arabidopsis lines with homozygous knockout mutations in the four individual LPA genes displayed normal flowers, pollen, and seed set. However, when all four LPAs were silenced simultaneously with a single RNA interference (RNAi) construct targeting the 3'UTR of each mRNA, obvious reproductive defects were observed. Western analysis of various Late Pollen actin RNA interference (LPRi) epialleles showed total LPA protein and RNA expression levels were knocked down from 0% to 95% compared to wild-type levels. Reciprocal crosses with the RNAi lines demonstrated that lowered LPA expression was associated with defects in both male and female fertility. Strong epialleles showed significant reductions in normal silique and seed production and were nearly sterile. Dissection of the siliques from moderate LPRi epialleles revealed many unfertilized ovules, increased numbers of aborted seeds, and decreased numbers of healthy seeds. Microscopic analysis of LPRi pollen indicated that the pollen shape and size were normal, but pollen germinated poorly. While multiple LPA genes may have some functional redundancy, the combined expression of multiple LPA genes appears essential to normal male and female reproductive development.

Eight infants with SCID-X1 had multilineage immune reconstitution after autologous hematopoietic stem-cell transplantation of marrow stem cells transfected with a lentiviral vector containing IL2RG cDNA after busulfan conditioning. Previous infections cleared and functional T cells developed in all eight infants, IgM levels normalized in seven, and three had a response to vaccines.

During the outmigration of Pacific Salmon, the early marine phase is a critical period when high mortality can occur. Traditional sampling and monitoring of juvenile salmon migration can be limited by logistically intensive gear requirements, accessibility, and cost. Improved understanding of the early marine phase, for example, migration duration and habitat use, requires innovative techniques that can improve the spatial and temporal coverage of monitoring. Environmental DNA (eDNA) is genetic fragments present in the environment that can be used as a proxy for organism presence and can be effectively and efficiently collected through water samples. Estimating fish abundance or biomass from eDNA concentration data would provide a valuable fisheries tool but remains challenging to calibrate. To quantify the relationship between eDNA abundance and fish biomass, we used a controlled mesocosm experiment, in which eDNA samples were collected from 15 aquaria (340 L) with varying densities of juvenile Chinook salmon per tank (0, 5, 10, 20, and 30). The concentration of eDNA was obtained by qPCR scaled with fish biomass (ANOVA, p < 0.05). However, we also observed that variability of eDNA concentrations among replicates of the same treatment positively scaled biomass (ANOVA, p < 0.05). Therefore, higher biomasses of fish can yield more challenging data to interpret. This study lays important groundwork for the application of eDNA for monitoring juvenile salmonids yet highlights caveats for the applicability of eDNA as a stand‐alone method to assess biomass in a field setting. A controlled mesocosm study was used to test the effect of juvenile Chinook salmon density/biomass on eDNA concentrations measured by qPCR. eDNA concentrations scaled positively with fish biomass, though variability among replicates within biomass treatments increased, meaning that higher biomasses of fish can yield more challenging data to interpret. This study lays important groundwork for the application of eDNA for monitoring juvenile salmonids yet highlights caveats for the applicability of eDNA as a stand‐alone method to assess biomass in a field setting.

Objects are commonly described based on their relations to other objects (e.g., associations, semantic similarity, etc.) or their physical features (e.g., birds have wings, feathers, etc.). However, objects can also be described in terms of their actionable properties (i.e., affordances), which reflect interactive relations between actors and objects. While several normed datasets have been developed to categorize various aspects of meaning (e.g., semantic features, cue–target associations, etc.), to date, norms for affordances have not been generated. We address this limitation by developing a set of affordance norms for 2825 concrete nouns. Using an open-response format, we computed affordance strength (AFS; i.e., the probability of an item eliciting a particular action response), affordance proportion (AFP; i.e., the proportion of participants who provided a specific action response), and affordance set size (AFSS; i.e., the total number of unique action responses) for each item. Because our stimuli overlapped with Pexman et al.’s, Behavior Research Methods, 51 , 453-466, ( 2019 ) body–object interaction norms (BOI), we tested whether AFS, AFP, and AFSS were related to BOI, as objects with more perceived action properties may be viewed as being more interactive. Additionally, we tested the relationship between AFS and AFP and two separate measures of relatedness: cosine similarity (Buchanan et al., Behavior Research Methods , 51 , 1849-1863, 2019a , Behavior Research Methods , 51 , 1878-1888, 2019b ) and forward associative strength (Nelson et al., Behavior Research Methods, Instruments, & Computers , 36 (3), 402–407, 2004 ). All analyses, however, revealed weak relationships between affordance measures and existing semantic norms, suggesting that affordance properties reflect a separate construct.