Brushing aside doubts: an evaluation of the beat-sheet brushing technique for detecting the Nearctic tree trunk sheetweaver (Araneae: Linyphiidae).

It is important to have reliable information on the presence/absence, population structure, and density of animals across their natural range. Detecting small organisms, however, such as the Nearctic tree trunk sheetweaver spider Drapetisca alteranda Chamberlin 1909 (Araneae: Linyphiidae), presents challenges due to its diminutive size and cryptic nature. We used a capture/recapture study to determine the detection and recapture probabilities of this spider using a standard beat sheet technique adopted for surveying tree trunks. Spiders were released on 3 different tree species that provided a range of microhabitats, including variable bark surface area and furrow depth/width. Microhabitat features played a small role in the timing of spider recapture (i.e., slower rate of recapture as furrowing increased). However, our results demonstrated 100% detection across replicate experiments and individual recapture probabilities exceeding 90% in most situations, with no significant differences in recapture observed among tree species and with respect to tree circumference. Furthermore, we show that most spiders could be recaptured within 2 sampling revolutions around the tree trunk, and there was no difference in the probability of collecting male and female spiders (although they differ markedly in size). Finally, we found no difference among brushers, supporting the idea that this method is replicable across collectors and studies. Collectively, we establish confidence in the ecological knowledge obtained with this technique and encourage its application with similar species and systems.

A Bacterial-Sourced Protein Diet Induces Beneficial Shifts in the Gut Microbiome of the Zebrafish, Danio rerio.

Background: Bacterial-sourced single-cell proteins (SCPs) offer an alternative protein source for diet formulation for Zebrafish (Danio rerio) and other aquaculture models. In addition, the use of a single-cell bacterial protein source derived from multiple species provides a unique insight into the interplay among nutrients in the diet, microbial populations in the diet, and the gut microbiome in D. rerio. Objective: Our objective in this study was to evaluate the impact of dietary replacement of fish protein hydrolysate in a standard reference (SR) with a single-cell bacterial protein source on D. rerio gut microbiome. Methods: We investigated gut microbial compositions of D. rerio fed an open-formulation standard reference (SR) diet or a bacterial-sourced protein (BP) diet, utilizing microbial taxonomic co-occurrence networks, and predicted functional profiles. Results: Microbial communities in the SR diet were primarily composed of Firmicutes. In contrast, the BP diet was mainly composed of Proteobacteria. Alpha diversity revealed significant differences in microbial communities between the 2 diets, and between the guts of D. rerio fed either of the 2 diets. D. rerio fed with the SR diet resulted in abundance of Aeromonas and Vibrio. In contrast, D. rerio fed with a BP diet displayed a large abundance of members from the Rhodobacteraceae family. Taxonomic co-occurrence networks display unique microbial interactions, and key taxons in D. rerio gut samples were dependent on diet and gender. Predicted functional profiling of the microbiome across D. rerio fed SR or BP diets revealed distinct metabolic pathway differences. Female D. rerio fed the BP diet displayed significant upregulation of pathways related to primary and secondary bile acid synthesis. Male D. rerio fed the BP diet revealed similar pathway shifts and, additionally, a significant upregulation of the polyketide sugar unit biosynthesis pathway. Conclusions: The use of a BP dramatically affects the composition and activity of the gut microbiome. Future investigations should further address the interplay among biological systems and diet and may offer insights into potential health benefits in preclinical and translational animal models.

Replacement of Dietary Fish Protein with Bacterial Protein Results in Decreased Adiposity Coupled with Liver Gene Expression Changes in Female Danio rerio.

Background: Effective use of Danio rerio as a preclinical model requires standardization of macronutrient sources to achieve scientific reproducibility across studies and labs. Objective: Our objective was to evaluate a bacterial-based single-cell protein (SCP) for the production of open-source standardized diets with defined health characteristics for the zebrafish research community. Methods: We completed a 16-wk feeding trial using juvenile D. rerio 31 d postfertilization (10 tanks per diet and 14 D. rerio per tank) with formulated diets containing either a typical fish protein ingredient [standard reference (SR) diet] or a novel bacterial SCP source [bacterial protein (BP) diet]. At the end of the feeding trial, growth metrics, body composition, reproductive success, and bulk transcriptomics of the liver (RNAseq on female D. rerio with confirmatory rtPCR) were performed for each diet treatment. Results: D. rerio fed the BP diet had body weight gains equivalent to the D. rerio fed fish protein, and females had significantly lower total carcass lipid, indicating reduced adiposity. Reproductive success was similar between treatments, suggesting normal physiological function. Genes differentially expressed in female D. rerio fed the BP diet compared with females fed the SR diet were overrepresented in the gene ontologies of metabolism, biosynthesis of cholesterol precursors and products, and protein unfolding responses. Conclusion: Protein source substantially affected body growth metrics and composition as well as gene expression. These data support the development of an open-source diet utilizing an ingredient that correlates with improved health profiles and reduced variability in notable outcomes.

Replacement of Dietary Fish Protein With Bacterial Single Cell Protein Results in Decreased Adiposity Coupled With Liver Expression Changes in Female Danio Rerio.

Background: Effective use of Danio rerio as a preclinical model requires standardization of macronutrient sources to achieve scientific reproducibility across studies and labs. Our objective was to evaluate single cell protein (SCP) for production of open-source standardized diets with defined heath characteristics for the zebrafish research community. We completed a 16-week feeding trial using juvenile D. rerio 31 days post-fertilization (dpf) (10 tanks per diet, 14 D. rerio per tank) with formulated diets containing either a typical fish protein ingredient or a novel bacterial SCP source. At the end of the feeding trial, growth metrics, body composition, reproductive success, and bulk transcriptomics of the liver (RNAseq on female D. rerio only with confirmatory rtPCR) were performed for each diet treatment. Results: D. rerio fed the SCP containing diet had body weight gains equivalent to the D. rerio fed fish protein, and females had significantly lower total carcass lipid, indicating reduced adiposity. Reproductive success was similar between treatments. Genes differentially expressed in female D. rerio provided the bacterial SCP compared to females given fish protein were overrepresented in the gene ontologies of metabolism, biosynthesis of cholesterol precursors and products, and protein unfolding responses. Conclusion: These data support the development of an open-source diet utilizing an ingredient that correlates with improved health profiles and reduced variability in notable outcomes.

Does Interactive Imagery Influence the Reactive Effect of Judgments of Learning on Memory?

Making judgments of learning (JOLs) while studying is a useful tool for students to evaluate the status of their learning. Additionally, in associative learning contexts, JOLs can directly benefit learning when the to-be-learned information is related. One explanation for this reactive effect is that making JOLs strengthens the associative relationship, leading to enhanced memory performance when a test relies on that relationship (e.g., cued-recall tests). In the present research, we evaluated whether having students make interactive mental images-another strategy that can increase the strength of a cue-target relationship-impacts the reactive effect of JOLs on learning. Students studied word pairs that were related and unrelated. Half of the students were instructed to form a mental image of the words interacting, whereas the other half were not. Additionally, in each group half of the students made a JOL for each pair, whereas half did not. Following a short delay, students completed a cued-recall test. Consistent with prior research, students who made JOLs remembered more related word pairs than did students who did not. By contrast, students who made JOLs recalled fewer unrelated word pairs than did students who did not. Moreover, although students who formed interactive images demonstrated enhanced memory relative to students who did not, interactive imagery did not impact the reactive effect of JOLs. These outcomes are informative for existing theory of JOL reactivity. Specifically, JOLs may only benefit learning of associative information when it has a pre-existing semantic relationship (e.g., related word pairs) and not when that that relationship is created by the learner (e.g., by forming interactive images).

Body Metrics and the Gut Microbiome in Response to Macronutrient Limitation in the Zebrafish Danio rerio.

Background: Healthy and predictable physiologic homeostasis is paramount in animal models for biomedical research. Proper macronutrient intake is an essential and controllable environmental factor for maintaining animal health and promoting experimental reproducibility. Objective and Methods: Evaluate reductions in dietary macronutrient composition on body weight metrics, composition, and gut microbiome in Danio rerio. Methods: D. rerio were fed reference diets deficient in either protein or lipid content for 14 weeks. Results: Diets of reduced-protein or reduced-fat resulted in lower weight gain than the standard reference diet in male and female D. rerio. Females fed the reduced-protein diet had increased total body lipid, suggesting increased adiposity compared with females fed the standard reference diet. In contrast, females fed the reduced-fat diet had decreased total body lipid compared with females fed the standard reference diet. The microbial community in male and female D. rerio fed the standard reference diet displayed high abundances of Aeromonas, Rhodobacteraceae, and Vibrio. In contrast, Vibrio spp. were dominant in male and female D. rerio fed a reduced-protein diet, whereas Pseudomonas displayed heightened abundance when fed the reduced-fat diet. Predicted functional metagenomics of microbial communities (PICRUSt2) revealed a 3- to 4-fold increase in the KEGG (Kyoto Encyclopedia of Genes and Genomes) functional category of steroid hormone biosynthesis in both male and female D. rerio fed a reduced-protein diet. In contrast, an upregulation of secondary bile acid biosynthesis and synthesis and degradation of ketone bodies was concomitant with a downregulation in steroid hormone biosynthesis in females fed a reduced-fat diet. Conclusions: These study outcomes provide insight into future investigations to understand nutrient requirements to optimize growth, reproductive, and health demographics to microbial populations and metabolism in the D. rerio gut ecosystem. These evaluations are critical in understanding the maintenance of steady-state physiologic and metabolic homeostasis in D. rerio. Curr Dev Nutr 20xx;x:xx.

Students' decisions to switch between categories or stay within them are related to practice classification performance.

How exemplars are ordered - blocked or interleaved - can play a critical role in later classification performance. Even so, when students self-regulate their learning, they typically block their study by choosing to stay within the same category on subsequent trials. Our goal was to evaluate the degree to which such decisions to stay within a category are influenced by performance on the previous practice trial. In five experiments, participants learned to classify categories of rocks by completing practice classification trials, receiving feedback, and making decisions about what to study on the next practice trial. The rate of stay choices was influenced by feedback type, a preceding familiarity trial, and location in the list. Most importantly, stay rates were low following correct classification demonstrating a preference to interleave study. By contrast, stay rates substantially increased following incorrect classification. Thus, practice classification performance and subsequent study decisions during complex categorical learning tasks can be strongly related.

Do Domain Knowledge and Retrieval Practice Predict Students' Study Order Decisions?

Learning complex concepts is necessary for student success, but it is often challenging. Learning such concepts can be influenced by students' study order choices during learning to switch to a new category (interleaved study order) or stay within the same category (blocked study order). Students often prefer stay decisions during learning and make relatively few switch decisions; however, an open question is whether students' switch decisions are related to their level of prior knowledge in the domain and the learning strategy they use (retrieval practice versus study). To examine these relationships, we recruited undergraduate students from an introductory geology course. Prior to the course modules on rock classification, students self-rated their knowledge, took a prior knowledge test, classified rock exemplars by completing study or retrieval practice trials, and made study order choices. Students then completed assignments and attended lectures in their geology course on igneous, sedimentary, and metamorphic rocks. Next, students self-rated their knowledge, took a new prior knowledge test, completed study or retrieval practice trials, made study order decisions, took final classification tests, and self-reported beliefs about study order choices. Even though students' knowledge increased after course modules on rock identification, and most students believed that domain knowledge impacts study decisions, prior knowledge did not predict students' switch decisions. In contrast, students who completed retrieval practice trials made substantially more switch decisions (i.e., interleaved study) than did students who completed study trials.

Poor body condition is associated with lower hippocampal plasticity and higher gut methanogen abundance in adult laying hens from two housing systems.

It is still unclear which commercial housing system provides the best quality of life for laying hens. In addition, there are large individual differences in stress levels within a system. Hippocampal neurogenesis or plasticity may provide an integrated biomarker of the stressors experienced by an individual. We selected 12 adult hens each with good and poor body condition (based on body size, degree of feather cover and redness of the comb) from a multi-tier free range system containing H&N strain hens, and from an enriched cage system containing Hy-Line hens (n = 48 total). Immature neurons expressing doublecortin (DCX) were quantified in the hippocampus, contents of the caecal microbiome were sequenced, and expression of inflammatory cytokines was measured in the spleen. DCX+ cell densities did not differ between the housing systems. In both systems, poor condition hens had lower DCX+ cell densities, exhibited elevated splenic expression of interleukin-6 (IL6) mRNA, and had a higher relative caecal abundance of methanogenic archea Methanomethylophilaceae. The findings suggest poor body condition is an indicator that individual hens have experienced a comparatively greater degree of cumulative chronic stress, and that a survey of the proportion of hens with poor body conditions might be one way to evaluate the impact of housing systems on hen welfare.

Older and younger adults' revision of health misconceptions.

Although ample younger adult research has detailed effective strategies for revising misconceptions, research with older adults is less extensive. Older adults may be less able to correct errors in knowledge due to age-related changes in cognition, but it is also possible that older adults' revision of misconceptions has been limited by methodologies which do not provide adequate support for correction. In two experiments, we examined how older and younger adults revise health-related misconceptions when provided with cognitive support in the form of explicit detailed feedback and an immediate test. Older and younger adults in Experiment 1 answered true/false health statements, received feedback with a detailed explanation of the correct response, took an additional test on the same statements immediately following the initial test, and completed a final test 1-week later. Older and younger adults corrected a similar proportion of misconceptions immediately and maintained most of those revisions across a 1-week delay. In Experiment 2, older adults corrected the same proportion of misconceptions on the final test regardless of whether or not they received a test immediately following feedback. Overall, older adults revised health misconceptions as effectively as did younger adults but variables influencing correction (e.g., belief in feedback) may differ.

Feed Intake as an Estimation of Attractability in Pacific White Shrimp Litopenaeus vannamei.

A simple bioassay that quantifies feed intake as an estimation of relative attractability of feeds containing different ingredients in the Pacific white shrimp Litopenaeus vannamei is described. Fish meal (FM), fish protein hydrolysate (FPH), squid meal (SqM) and casein (CN) were assessed at the same dietary level for their relative influence on feed intake rates of Litopenaeus vannamei. A bland diet containing 92% whole wheat grain meal, 6% diatomaceous earth and 2% alginate with a known low attractability was used as the standard control or base diet. Ingredients were added to the bland base control diet at a level of 3% as fed. Shrimp were stocked into 80 L glass tanks (n= 20 per tank) in a recirculating aquaculture system. Tanks were randomly assigned to one of five diet treatments (3tanks/treatment). Experiments measuring the attractability of each feed were conducted twice daily at 0900 hours and 1330 hours over a five day period. For each experiment, 40 feed pellets (ca. 1 g) corresponding to the assigned treatment were provided to each tank. To calculate the rate of feed intake, pellets remaining in each tank were counted at six minute intervals for a seventy-two minute period. Differences in rate of feed intake among diets were evaluated using Cox Regression Analysis. This attractability assay required only small amounts of ingredients and incorporated ingredients into a bland feed, which significantly reduces the influence from other ingredients or compound in the pellets. All of the test protein ingredients, especially SqM, in the feeds significantly increased the feed consumption rate. The diet containing SqM was consumed at a significantly higher rate than those containing casein and FM but not FPH. FPH and CN containing diets were not significantly different but consumed at a higher rate than the diet containing FM. Results of these trials indicate that the presence of certain ingredients can increase feed intake, thereby increasing nutrient availability of the diets. This reported method to determine consumption of diets containing certain ingredients can be considered as a valid method to estimate attractability.

Development and evaluation of a method for segmentation of cardiac, subcutaneous, and visceral adipose tissue from Dixon magnetic resonance images.

Magnetic resonance imaging (MRI) has evolved into the gold standard for quantifying excess adiposity, but reliable, efficient use in longitudinal studies requires analysis of large numbers of images. The objective of this study is to develop and evaluate a segmentation method designed to identify cardiac, subcutaneous, and visceral adipose tissue (VAT) in Dixon MRI scans. The proposed method is evaluated using 10 scans from volunteer females 18- to 35-years old, with body mass indexes between 30 and 39.99 kg / m 2 . Cross-sectional area (CSA) for cardiac adipose tissue (CAT), subcutaneous adipose tissue (SAT), and VAT, is compared to manually-traced results from three observers. Comparisons of CSA are made in 191 images for CAT, 394 images for SAT, and 50 images for VAT. The segmentation correlated well with respect to average observer CSA with Pearson correlation coefficient ( R 2 ) values of 0.80 for CAT, 0.99 for SAT, and 0.99 for VAT. The proposed method provides accurate segmentation of CAT, SAT, and VAT and provides an option to support longitudinal studies of obesity intervention.

Effects of Dietary Carbohydrate on Weight Gain and Gonad Production in Small Sea Urchins, Lytechinus variegatus.

In experiment 1, juvenile sea urchins (n = 80, 0.088 ± 0.001 g wet weight and 5.72 ± 0.04 mm diameter) were held individually and fed ad libitum one of three semi-purified formulated diets (n = 16 individuals treatment-1). In the diets, protein was held constant (310g kg-1 dry, as fed) and carbohydrate level varied (190, 260, or 380 g kg-1 dry, as fed). Wet weights were measured every 2 weeks. Total wet weight gain was inversely proportional to dietary carbohydrate level and energy content of the respective diet. In experiment 2, sea urchins (5.60 ± 0.48g wet weight, n= 40) fed 190 g kg-1 carbohydrate consumed significantly more dry feed than those fed 260 g kg-1, but not more than those fed 380 g kg-1 carbohydrate. Based on differential feed intake rates, sea urchins that consumed more feed also consumed higher levels of protein and had the highest weight gain. Consequently, protein content and/or protein: energy ratio may be important in determining feed utilization and growth among sea urchins in this study. The average digestible energy intake was approximately 70 kcal kg-1 body weight day-1, suggesting daily caloric intake of juvenile Lytechinus variegatus is lower than in shrimp and fish.

PRODUCTION AND ECONOMIC OPTIMIZATION OF DIETARY PROTEIN AND CARBOHYDRATE IN THE CULTURE OF JUVENILE SEA URCHIN Lytechinus variegatus.

Juvenile Lytechinus variegatus (ca. 3.95± 0.54 g) were fed one of 10 formulated diets with different protein (ranging from 11- 43%) and carbohydrate (12 or 18%; brackets determined from previous studies) levels. Urchins (n= 16 per treatment) were fed a daily sub-satiation ration equivalent to 2.0% of average body weight for 10 weeks. Our objective was (1) to create predictive models of growth, production and efficiency outcomes and (2) to generate economic analysis models in relation to these dietary outcomes for juvenile L. variegatus held in culture. At dietary protein levels below ca. 30%, models for most growth and production outcomes predicted increased rates of growth and production among urchins fed diets containing 18% dietary carbohydrate levels as compared to urchins fed diets containing 12% dietary carbohydrate. For most outcomes, growth and production was predicted to increase with increasing level of dietary protein up to ca. 30%, after which, no further increase in growth and production were predicted. Likewise, dry matter production efficiency was predicted to increase with increasing protein level up to ca. 30%, with urchins fed diets with 18% carbohydrate exhibiting greater efficiency than those fed diets with 12% carbohydrate. The energetic cost of dry matter production was optimal at protein levels less than those required for maximal weight gain and gonad production, suggesting an increased energetic cost (decreased energy efficiency) is required to increase gonad production relative to somatic growth. Economic analysis models predict when cost of feed ingredients are low, the lowest cost per gram of wet weight gain will occur at 18% dietary carbohydrate and ca. 25- 30% dietary protein. In contrast, lowest cost per gram of wet weight gain will occur at 12% dietary carbohydrate and ca. 35- 40% dietary protein when feed ingredient costs are high or average. For both 18 and 12% levels of dietary carbohydrate, cost per gram of wet weight gain is predicted to be maximized at low dietary protein levels, regardless of feed ingredient costs. These models will compare dietary requirements and growth outcomes in relation to economic costs and provide insight for future commercialization of sea urchin aquaculture.

Optimizing dietary levels of menhaden and soybean oils and soybean lecithin for pre-gonadal somatic growth in juveniles of the sea urchin Lytechinus variegatus.

Dietary lipids serve as important sources of energy and essential fatty acids for aquatic animals. Sources of animal and plant oils are increasingly limited as well as expensive, and dietary requirements associated with the inclusion of these oils must be carefully evaluated to facilitate sustainable and affordable formulations. In this study, we investigated quantities of menhaden oil (MO) with and without soybean lecithin or soybean oil (SO) to determine appropriate levels for optimal somatic growth for pre-gonadal juvenile Lytechinus variegatus. We prepared semi-purified diets that varied in neutral lipid content (0, 2, 4, or 8% dry matter) and soy lecithin (0 or 2%) and exchanged lipids reciprocally with purified starch while holding constant all other nutrients. We maintained laboratory-reared juvenile L. variegatus (average initial wet weight 82 ± 0.7 mg, mean ± SE , n = 9 treatment-1) in recirculating seawater systems and fed each daily a sub-satiation ration for five weeks. We assessed wet weights and test diameters every two weeks and at the end of the experiment (5 wk). Level of MO with or without soybean lecithin did not significantly affect wet weight gain; however, increasing levels of SO in the diet reduced wet weight gain and dry matter production efficiency and increased feed conversion ratio. Dry gut weight was positively correlated with level of MO. Lipid level in the gut increased with increasing dietary lipid level, regardless of source. These data suggest the composition of the SO is inhibitory for either nutrient absorption or metabolic processes associated with growth at this life stage. Diets containing total lipid levels of approximately 5 to 6% that include sources of n-3 fatty acids may support optimal growth for pre-gonadal juvenile L. variegatus.

EFFECT OF DIETARY PROTEIN AND CARBOHYDRATE LEVELS ON WEIGHT GAIN AND GONAD PRODUCTION IN THE SEA URCHIN LYTECHINUS VARIEGATUS.

Adult Lytechinus variegatus were fed eight formulated diets with different protein (ranging from 12 to 36%) and carbohydrate (ranging from 21 to 39 %) levels. Each sea urchin (n = 8 per treatment) was fed a daily sub-satiation ration of 1.5% of average body weight for 9 weeks. Akaike information criterion analysis was used to compare six different hypothesized dietary composition models across eight growth measurements. Dietary protein level and protein: energy ratio were the best models for prediction of total weight gain. Diets with the highest (> 68.6 mg P kcal--1) protein: energy ratios produced the most wet weight gain after 9 weeks. Dietary carbohydrate level was a poor predictor for most growth parameters examined in this study. However, the model containing a protein × carbohydrate interaction effect was the best model for protein efficiency ratio (PER). PER decreased with increasing dietary protein level, more so at higher carbohydrate levels. Food conversion ratio (FCR) was best modeled by total dietary energy levels: Higher energy diets produced lower FCRs. Dietary protein level was the best model of gonad wet weight gain. These data suggest that variations in dietary nutrients and energy differentially affect organismal growth and growth of body components.

EFFECT OF DIET QUALITY ON NUTRIENT ALLOCATION TO THE TEST AND ARISTOTLE'S LANTERN IN THE SEA URCHIN LYTECHINUS VARIEGATUS (LAMARCK, 1816).

Small adult (19.50 ± 2.01g wet weight) Lytechinus variegatus were fed eight formulated diets with different protein (12 to 36% dry weight as fed) and carbohydrate (21 to 39 % dry weight) levels. Each sea urchin (n = 8 per treatment) was fed a daily ration of 1.5% of the average body weight of all individuals for 9 weeks. Akaike information criterion scores were used to compare six different dietary composition hypotheses for eight growth measurements. For each physical growth response, different mathematical models representing a priori hypotheses were compared using the Akaike Information Criterion (AIC) score. The AIC is one of many information-theoretic approaches that allows for direct comparison of non-nested models with varying number of parameters. Dietary protein level and protein: energy ratio were the best models for prediction of test diameter increase. Dietary protein level was the best model of test with spines wet weight gain and test with spines dry matter production. When the Aristotle's lantern was corrected for size of the test, there was an inverse relationship with dietary protein level. Log transformed lantern to test with spines index was also best associated with the dietary protein model. Dietary carbohydrate level was a poor predictor for growth parameters. However, the protein × carbohydrate interaction model was the best model of organic content (% dry weight) of the test without spines. These data suggest that there is a differential allocation of resources when dietary protein is limiting and the test with spines, but not the Aristotle's lantern, is affected by availability of dietary nutrients.

Knowledge, attitude and practice of emergency contraceptive pills among tertiary level students in Trinidad: a cross-sectional survey / Conocimientos, actitudes y práctica de las píldoras anticonceptivas de emergencia entre estudiantes de nivel terciario en Trinidad: un estudio transversal

OBJECTIVE: The objective of this study was to estimate the general knowledge, attitude and practice of Emergency Contraceptive pills (ECs) among tertiary level students in Trinidad. METHOD: A 32-item questionnaire was constructed to assess knowledge, attitudes and practice of EC. There were 76 medical and 160 non-medical students who volunteered to fill-up the questionnaire. This survey was conducted by graduate students under supervision of the Department of Mathematics and Computer Science, UWI, St Augustine. RESULTS: Eighty-four per cent of the students were less than 25 years of age, 64% were Christians and 92% were single. Sixty-three per cent were female and there were more females in the non-medical group than the medical students group but the numbers were not significant. Eighty-one per cent used condoms as the main type ofcontraception. Only 63% had heard of ECs before and only 9% had heard of ECs from medical sources. Among the factors that related to attitude towards EC, only two factors were significant. Sixty-two per cent of students felt that increased EC use would increase promiscuity (p = 0.013) but 59% also felt that ECs should be made more easily available (p = 0.014). CONCLUSION: The general level of their knowledge about ECs was poor. The general attitude of students towards ECs was positive. This study will help policy-makers by providing evidence-based knowledge to promote EC use among university students.

OBJETIVO: El objetivo de este estudio fue evaluar de manera general los conocimientos, actitudes y prácticas en relación con las píldoras anticonceptivas de emergencia (PAE) entre estudiantes de nivel terciario en Trinidad. MÉTODO: Se diseñó una encuesta de 32 puntos con el propósito de evaluar los conocimientos, actitudes y prácticas de la anticoncepción de emergencia (AE). Hubo 76 estudiantes de medicina y 160 de otras carreras que se ofrecieron voluntariamente para responder la encuesta. RESULTADOS: El 84 por ciento de los estudiantes tenían menos de 25 años de edad, el 64% eran cristianos, y el 92% eran solteros. El 63 por ciento eran hembras y había más hembras en el grupo de estudiantes no médicos que en el grupo de estudiantes de medicina, pero las cifras no fueron significativas. El 81 por ciento usaban condones como tipo principal de contracepción. Solamente un 63% había oído de las PAEs y sólo el 9% había oído de las PAEs a partir de fuentes médicas. Entre los factores relacionados con las actitudes hacia las PAEs, sólo dos factores fueron significativos. El 62 por ciento de los estudiantes sentían que un aumento en el uso de la AE equivaldría a un aumento de la promiscuidad (p = 0.013), pero el 59% también tenía la percepción de que las PAEs debían estar más fácilmente al alcance de todos (p = 0.014). CONCLUSIÓN: En términos generales, el nivel de los conocimientos de los estudiantes sobre las PAEs fue en términos generales pobre, Su actitud general hacia las PAEs fue positiva. Este estudio ayudará a quienes tienen a su cargo el trazar políticas, brindándole conocimientos basados en evidencias, a promover el uso de PAEs entre los estudiantes universitarios.

Knowledge, attitude and practice of emergency contraceptive pills among tertiary level students in Trinidad: a cross-sectional survey.

OBJECTIVE: The objective of this study was to estimate the general knowledge, attitude and practice of Emergency Contraceptive pills (ECs) among tertiary level students in Trinidad. METHOD: A 32-item questionnaire was constructed to assess knowledge, attitudes and practice of EC. There were 76 medical and 160 non-medical students who volunteered to fill-up the questionnaire. This survey was conducted by graduate students under supervision of the Department of Mathematics and Computer Science, UWI, St Augustine. RESULTS: Eighty-four per cent of the students were less than 25 years of age, 64% were Christians and 92% were single. Sixty-three per cent were female and there were more females in the non-medical group than the medical students group but the numbers were not significant. Eighty-one per cent used condoms as the main type of contraception. Only 63% had heard of ECs before and only 9% had heard of ECs from medical sources. Among the factors that related to attitude towards EC, only two factors were significant. Sixty-two per cent of students felt that increased EC use would increase promiscuity (p = 0.013) but 59% also felt that ECs should be made more easily available (p = 0.014). CONCLUSION: The general level of their knowledge about ECs was poor. The general attitude of students towards ECs was positive. This study will help policy-makers by providing evidence-based knowledge to promote EC use among university students.

Acetylcholinesterase in the sea urchin Lytechinus variegatus: characterization and developmental expression in larvae.

Acetylcholinesterase (AChE) in the echinoid Lytechinus variegatus has been characterized. Kinetic parameters V(max), K(m), K(ss), and b were 2594+/-1048 nmol ATCh hydrolyzed/min/mg tissue wet weight, 185+/-11 microM, 308+/-100 mM, and 0.2, respectively for the substrate ATCh and 17.8+/-6.87 nmol BTCh hydrolyzed/min/mg tissue wet weight, 654+/-424 microM, 36+/-31 mM, and 0.6, respectively for BTCh. Pharmacologic analyses were performed with four inhibitors of cholinesterases, physostigmine, BW284c51, ethopropazine, and iso-OMPA, and yielded IC(50) values of 106+/-4 nM, 718+/-118 nM, 2.57+/-0.6 mM, and >0.0300 M, respectively. Both kinetic and pharmacologic results confirmed the existence of AChE in larval L. variegatus. Dimeric and tetrameric globular forms (determined by velocity sedimentation on sucrose gradients) were present in L. variegatus larvae. Activity of AChE increased significantly as larvae progressed in development from embryos to eight-arm larvae. Acetylcholinesterase activity of F1 larvae derived from sea urchins collected from wild populations and of F1 larvae derived from sea urchins cultured in the laboratory and fed two different diets suggest that the nutritional and/or environmental history of the adult sea urchin affect the developmental progression of AChE activity in the F1 offspring.