Digestion of copepod eggs by larval turbot Scophthalmus maximus and egg viability following gut passage

Between 20.5 and 93.6 % of the subitaneous eggs of 6 species of egg-carrying copepods passed undigested through the digestive tracts of larval and early postlarval turbot Scophthalmus maximus. Viability of the eggs of Eurytemora affinis, E. velox and Euterpina acutifrons remained high on egestion (67.0 to 91.7 %), Pseudocalanus elongatus and Oncaea venusta eggs had low viability (1.1 to 1.5 %), while all Corycaeus anglicus eggs were rendered inviable. The indigestibility of the eggs denies the turbot larvae a potentially valuable food resource, while retention of high egg viability in certain species reduces the effect of predation

Maternal Intuition of Fetal Gender

Purpose: Fetal gender speculation is a preoccupation of many expecting parents, and pregnant women commonly profess to intuitively know the gender of their unborn babies. This study objectively compared pregnant mothers’ perceptions of fetal gender to sonographically proven gender determinations. Also, success rates from previously published studies, noninvasive prenatal testing and a myriad of gender determination methods were observed and reported for context. Methods: All pregnant women presenting for second-trimester screening ultrasound (at 17–23 weeks gestation) in the obstetrics department of a single health center were asked to participate. A medical sonographer described the ultrasound examination, obtained appropriate consent and medical history. Each mother was asked if she had any perception as to the fetal gender and her answer documented. Mothers who had foreknowledge of fetal gender were excluded. Frequencies of actual gender were compared with observed frequencies of the maternal prediction using chi-squared test. Results: Approximately 40% (n = 411) of our study population (N = 1,026) indicated having an intuition or perception of fetal gender. These women correctly predicted the gender of their babies 51% of the time (P = 0.6571). Women who expressed a “strong” degree of intuition (n = 53) fared better, accurately predicting fetal gender at a rate of 62%, though the difference in this smaller subcohort also failed to demonstrate statistical significance (P = 0.0741). Conclusions: Intuition of fetal gender is professed by almost half of mothers though, when present, is no better at accurately predicting fetal gender than flipping a coin

Emergent synergistic lysosomal toxicity of chemical mixtures in molluscan blood cells (hemocytes)

The problem of effective assessment of risk posed by complex mixtures of toxic chemicals in the environment is a major challenge for government regulators and industry. The biological effect of the individual contaminants, where these are known, can be measured; but the problem lies in relating toxicity to the multiple constituents of contaminant cocktails. The objective of this study was to test the hypothesis that diverse contaminant mixtures may cause a greater toxicity than the sum of their individual parts, due to synergistic interactions between contaminants with different intracellular targets. Lysosomal membrane stability in hemocytes from marine mussels was used for in vitro toxicity tests; and was coupled with analysis using the isobole method and a linear additive statistical model. The findings from both methods have shown significant emergent synergistic interactions between environmentally relevant chemicals (i.e., polycyclic aromatic hydrocarbons, pesticides, biocides and a surfactant) when exposed to isolated hemocytes as a mixture of 3 & 7 constituents. The results support the complexity-based hypothesis that emergent toxicity occurs with increasing contaminant diversity, and raises questions about the validity of estimating toxicity of contaminant mixtures based on the additive toxicity of single components. Further experimentation is required to investigate the potential for interactive effects in mixtures with more constituents (e.g., 50 –100) at more environmentally realistic concentrations in order to test other regions of the model, namely, very low concentrations and high diversity. Estimated toxicant diversity coupled with tests for lysosomal damage may provide a potential tool for determining the toxicity of estuarine sediments, dredge spoil or contaminated soil

What makes school a positive experience for 12 junior high school students?

vii, 154 leaves ; 28 cm.This study examined the perceptions and needs of junior high school students considering the question, What makes school a positive experience for 12 junior high school students? Previous research indicates that many students view school negatively (Bibby & Posterski, 1992). This conclusion is an alarming statement considering the significant number of years students spend in school. Using student written responses and interviews, this study explored the peceptions of junior high school students in relation to school. Qualitative research method was used as it allowed the researcher to collect and document rich data that helped to shed light on students' views of junior high school. Twelve students, 2 males and 2 females, from each of the three junior high grades (7,8, and 9) participated in the study. The students were asked to respond, in writing, to five prompts: 1) Junior high school is...2) What do you think can make junior high a positvie place to be? 3) What do you think can make junior high a negative place to be? 4) The best thing about my school is...5) The worst thing about my school is... . Those same students then met in grade level groups for an interview used to clarify and expand upon the themes that emerged in their written responses. The final data-gathering technique was for the students to reflect upon what the ideal school might look like. Overall, the results of this study indicate that students value relationships with both teachers and peers and wish to belong to the safe and student-centered community of school. The insights of junior high school students about their schooling experience will assist in the organization of programs designed to meet the needs of adolescents within an educational setting

Bedbugs evolved before their bat hosts and did not co-speciate with ancient humans

All 100+ bedbug species (Cimicidae) are obligate blood-sucking parasites [1, 2]. In general, blood sucking (hematophagy) is thought to have evolved in generalist feeders adventitiously taking blood meals [3, 4], but those cimicid taxa currently considered ancestral are putative host specialists [1, 5]. Bats are believed to be the ancestral hosts of cimicids [1], but a cimicid fossil [6] predates the oldest known bat fossil [7] by >30 million years (Ma). The bedbugs that parasitize humans [1, 8] are host generalists, so their evolution from specialist ancestors is incompatible with the "resource efficiency" hypothesis and only partially consistent with the "oscillation" hypothesis [9-16]. Because quantifying host shift frequencies of hematophagous specialists and generalists may help to predict host associations when vertebrate ranges expand by climate change [17], livestock, and pet trade in general and because of the previously proposed role of human pre-history in parasite speciation [18-20], we constructed a fossil-dated, molecular phylogeny of the Cimicidae. This phylogeny places ancestral Cimicidae to 115 mya as hematophagous specialists with lineages that later frequently populated bat and bird lineages. We also found that the clades, including the two major current urban pests, Cimex lectularius and C. hemipterus, separated 47 mya, rejecting the notion that the evolutionary trajectories of Homo caused their divergence [18-21]

Effect of Sub-Lethal Exposure to Ultraviolet Radiation on the Escape Performance of Atlantic Cod Larvae (Gadus morhua)

The amount of ultraviolet (UV) radiation reaching the earth's surface has increased due to depletion of the ozone layer. Several studies have reported that UV radiation reduces survival of fish larvae. However, indirect and sub-lethal impacts of UV radiation on fish behavior have been given little consideration. We observed the escape performance of larval cod (24 dph, SL: 7.6±0.2 mm; 29 dph, SL: 8.2±0.3 mm) that had been exposed to sub-lethal levels of UV radiation vs. unexposed controls. Two predators were used (in separate experiments): two-spotted goby (Gobiusculus flavescens; a suction predator) and lion's mane jellyfish (Cyanea capillata; a “passive" ambush predator). Ten cod larvae were observed in the presence of a predator for 20 minutes using a digital video camera. Trials were replicated 4 times for goby and 5 times for jellyfish. Escape rate (total number of escapes/total number of attacks ×100), escape distance and the number of larvae remaining at the end of the experiment were measured. In the experiment with gobies, in the UV-treated larvae, both escape rate and escape distance (36%, 38±7.5 mm respectively) were significantly lower than those of control larvae (75%, 69±4.7 mm respectively). There was a significant difference in survival as well (UV: 35%, Control: 63%). No apparent escape response was observed, and survival rate was not significantly different, between treatments (UV: 66%, Control: 74%) in the experiment with jellyfish. We conclude that the effect and impact of exposure to sub-lethal levels of UV radiation on the escape performance of cod larvae depends on the type of predator. Our results also suggest that prediction of UV impacts on fish larvae based only on direct effects are underestimations

The role of multixenobiotic transporters in predatory marine molluscs as counter-defense mechanisms against dietary allelochemicals

Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 152 (2010): 288-300, doi:10.1016/j.cbpc.2010.05.003.Multixenobiotic transporters have been extensively studied for their ability to modulate the disposition and toxicity of pharmacological agents, yet their influence in regulating the levels of dietary toxins within marine consumers has only recently been explored. This study presents functional and molecular evidence for multixenobiotic transporter-mediated efflux activity and expression in the generalist gastropod Cyphoma gibbosum, and the specialist nudibranch Tritonia hamnerorum, obligate predators of chemically defended gorgonian corals. Immunochemical analysis revealed that proteins with homology to permeability glycoprotein (P-gp) were highly expressed in T. hamnerorum whole animal homogenates and localized to the apical tips of the gut epithelium, a location consistent with a role in protection against ingested prey toxins. In vivo dye assays with specific inhibitors of efflux transporters demonstrated the activity of P-gp and multidrug resistance-associated protein (MRP) families of ABC transporters in T. hamnerorum. In addition, we identified eight partial cDNA sequences encoding two ABCB and two ABCC proteins from each molluscan species. Digestive gland transcripts of C. gibbosum MRP-1, which have homology to vertebrate glutathione-conjugate transporters, were constitutively expressed regardless of gorgonian diet. This constitutive expression may reflect the ubiquitous presence of high affinity substrates for C. gibbosum glutathione transferases in gorgonian tissues likely necessitating export by MRPs. Our results suggest that differences in multixenobiotic transporter expression patterns and activity in molluscan predators may stem from the divergent foraging strategies of each consumer.Financial support was provided by the Ocean Life Institute Tropical Research Initiative Grant (WHOI) to KEW and MEH; the Robert H. Cole Endowed Ocean Ventures Fund (WHOI) to KEW; the National Undersea Research Center – Program Development Proposal (CMRC-03PRMN0103A) to KEW; and the National Science Foundation (Graduate Research Fellowship to KEW and DEB-0919064 to EES)

Exploring the presence of pathological demand avoidance in school aged children

This research studied the presence of PDA (an obsessional avoidance of life’s ordinary demands along with high skills of social manipulation) in typically developing children and those diagnosed with autism, Attention Deficit Hyperactivity Disorder (ADHD) and/or anxiety disorders. Children with autism were hypothesized to have higher incidence of PDA than children without autism. Purposive sampling was used in participant recruitment. Findings should be understood within the indicated limitations. A sample of 78 participants responded to an on-line questionnaire that collected information on the presence of PDA. There was a statistically significant difference in the PDA scores for children with and without a clinical diagnosis (autism, ADHD, anxiety). Children diagnosed with autism had significantly different (higher) PDA scores than children without autism. No other comparisons were significant. The results support the hypothesis that children who have autism have more intense symptoms of PDA than those without autism