Response of Runoff Diazinon Concentration to Formulation and Post-Application Irrigation

Pesticides used in urban environments can be transported in runoff to downstream waters and cause adverse environmental consequences. This experiment assessed the effects of post-application irrigation depth (0, 6.4, and 12.7 mm) and formulation (liquid and granular) on concentration and transport of diazinon (a pesticide commonly used for lawn insect control) in runoff from “tall” fescue (Festuca arundinacea Schreb.) plots. The post-application irrigation was applied using rainfall simulators immediately following diazinon application. The rainfall simulators were again used approximately 2 h after diazinon application to apply the equivalent of a heavy rainfall (64 mm/h for approximately 1.5 h) to generate runoff. Runoff was sampled and analyzed for diazinon using the enzyme-linked immuno-sorbent assay method. Post-application irrigation depth had no effect on diazinon concentration but increased diazinon mass transported off the plot by increasing plot runoff. Flow-weighted mean runoff diazinon concentration for the liquid formulation of diazinon was roughly double that of the granular formulation (0.59 vs 0.29 mg/L), attributed to the higher solubility of the liquid formulation relative to the granular formulation. The results indicate that post-application irrigation can increase runoff losses of diazinon for heavy rainfall occurring soon after application, but that these losses can be reduced by use of the granular formulation

Asymmetrical Interference Effects Between Two-Dimensional Geometric Shapes and Their Corresponding Shape Words

Nativists have postulated fundamental geometric knowledge that predates linguistic and symbolic thought. Central to these claims is the proposal for an isolated cognitive system dedicated to processing geometric information. Testing such hypotheses presents challenges due to difficulties in eliminating the combination of geometric and non-geometric information through language. We present evidence using a modified matching interference paradigm that an incongruent shape word interferes with identifying a two-dimensional geometric shape, but an incongruent two-dimensional geometric shape does not interfere with identifying a shape word. This asymmetry in interference effects between two-dimensional geometric shapes and their corresponding shape words suggests that shape words activate spatial representations of shapes but shapes do not activate linguistic representations of shape words. These results appear consistent with hypotheses concerning a cognitive system dedicated to processing geometric information isolated from linguistic processing and provide evidence consistent with hypotheses concerning knowledge of geometric properties of space that predates linguistic and symbolic thought

VP24-Karyopherin alpha binding affinities differ between Ebolavirus species, nfluencing interferon inhibition and VP24 stability

Zaire ebolavirus (EBOV), Bundibugyo ebolavirus (BDBV), and Reston ebolavirus (RESTV) belong to the same genus but exhibit different virulence properties. VP24 protein, a structural protein present in all family members, blocks interferon (IFN) signaling and likely contributes to virulence. Inhibition of IFN signaling by EBOV VP24 (eVP24) involves its interaction with the NPI-1 subfamily of karyopherin alpha (KPNA) nuclear transporters. Here, we evaluated eVP24, BDBV VP24 (bVP24), and RESTV VP24 (rVP24) interactions with three NPI-1 subfamily KPNAs (KPNA1, KPNA5, and KPNA6). Using purified proteins, we demonstrated that each VP24 binds to each of the three NPI-1 KPNAs. bVP24, however, exhibited approximately 10-fold-lower KPNA binding affinity than either eVP24 or rVP24. Cell-based assays also indicate that bVP24 exhibits decreased KPNA interaction, decreased suppression of IFN induced gene expression, and a decreased half-life in transfected cells compared to eVP24 or rVP24. Amino acid sequence alignments between bVP24 and eVP24 also identified residues within and surrounding the previously defined eVP24-KPNA5 binding interface that decrease eVP24-KPNA affinity or bVP24-KPNA affinity. VP24 mutations that lead to reduced KPNA binding affinity also decrease IFN inhibition and shorten VP24 half-lives. These data identify novel functional differences in VP24-KPNA interaction and reveal a novel impact of the VP24-KPNA interaction on VP24 stability. IMPORTANCE The interaction of Ebola virus (EBOV) VP24 protein with host karyopherin alpha (KPNA) proteins blocks type I interferon (IFN) signaling, which is a central component of the host innate immune response to viral infection. Here, we quantitatively compared the interactions of VP24 proteins from EBOV and two members of the Ebolavirus genus, Bundibugyo virus (BDBV) and Reston virus (RESTV). The data reveal lower binding affinity of the BDBV VP24 (bVP24) for KPNAs and demonstrate that the interaction with KPNA modulates inhibition of IFN signaling and VP24 stability. The effect of KPNA interaction on VP24 stability is a novel functional consequence of this virus-host interaction, and the differences identified between viral species may contribute to differences in pathogenesis

Adverse childhood experiences exacerbate the association between day-to-day discrimination and mental health symptomatology in undergraduate students

Background: Background: Background: Adverse childhood experiences (ACEs) and day-to-day discrimination (hereafter, “discrimination”) both contribute to mental health symptomatology in young adulthood, but how these constructs interact and whether they are associated with mental health remains unclear. This study evaluated whether the relation between discrimination in young adulthood and mental health symptomatology varied as a function of ACEs exposure. Methods: Undergraduates (n = 251) completed self-report measures related to ACEs, discrimination, and mental health symptomatology (i.e., depression, anxiety, somatization, and psychological distress). Linear and logistic regression models were implemented to test for potential exacerbation effects of ACEs on the relation between discrimination and mental health symptomatology. Results: Participants with greater discrimination exposure and ACEs reported significantly more depression, anxiety, and somatic symptoms, along with more psychological distress, relative to those with less discrimination exposure and few or no ACEs. Limitations: Data were cross-sectional, thus, causality cannot be inferred. ACEs and discrimination measures examined ACE counts and general discrimination, respectively, which did not allow for examination of possible differences across specific ACEs (e.g., childhood sexual abuse vs. neglect) or specific types of discrimination (e.g., sexual-orientation-based discrimination vs. race-based discrimination). Conclusions: Conclusions: These results are among the first to inform the conceptualization of ACEs and discrimination in etiological models of young adults’ mental health. Both ACEs and discrimination, rather than exposure to only one of these stressors, may be synergistically associated with young adults’ mental health symptomatology. Clinicians could address stress-sensitive mental health issues by assessing for both ACEs and discrimination exposure

Force distributions in a triangular lattice of rigid bars

We study the uniformly weighted ensemble of force balanced configurations on a triangular network of nontensile contact forces. For periodic boundary conditions corresponding to isotropic compressive stress, we find that the probability distribution for single-contact forces decays faster than exponentially. This super-exponential decay persists in lattices diluted to the rigidity percolation threshold. On the other hand, for anisotropic imposed stresses, a broader tail emerges in the force distribution, becoming a pure exponential in the limit of infinite lattice size and infinitely strong anisotropy.Comment: 11 pages, 17 figures Minor text revisions; added references and acknowledgmen

A novel method for the evaluation of proximal tubule epithelial cellular necrosis in the intact rat kidney using ethidium homodimer

BACKGROUND: Ethidium homodimer is a cell-membrane impermeant nuclear fluorochrome that has been widely used to identify necrotic cells in culture. Here, we describe a novel technique for evaluating necrosis of epithelial cells in the proximal tubule that involves perfusing ethidium homodimer through the intact rat kidney. As a positive control for inducing necrosis, rats were treated with 3.5, 1.75, 0.87 and 0.43 mg/kg mercuric chloride (Hg(2+), intraperitoneal), treatments which have previously been shown to rapidly cause dose-dependent necrosis of the proximal tubule. Twenty-four h after the administration of Hg(2+), ethidium homodimer (5 μM) was perfused through the intact left kidney while the animal was anesthetized. The kidney was then removed, placed in embedding medium, frozen and cryosectioned at a thickness of 5 μm. Sections were permeabilized with -20°C methanol and then stained with 4',6-diamidino-2-phenylindole (DAPI) to label total nuclei. Total cell number was determined from the DAPI staining in random microscopic fields and the number of necrotic cells in the same field was determined by ethidium homodimer labeling. RESULTS: The Hg(2+)-treated animals showed a dose-dependent increase in the number of ethidium labeled cells in the proximal tubule, but not in other segments of the nephron. Other results showed that a nephrotoxic dose of gentamicin also caused a significant increase in the number of ethidium labeled cells in the proximal tubule. CONCLUSION: These results indicate that this simple and sensitive perfusion technique can be used to evaluate cellular necrosis in the proximal tubule with the three-dimensional cyto-architecture intact

7700-Year Persistence of an Isolated, Free-Living Coral Assemblage in the Galapagos Islands: A Model for Coral Refugia?

In an eastern-Pacific coral assemblage at Devil’s Crown, Galápagos Islands, Ecuador, two coral species, Psammocora stellata and Cycloseris (Diaseris) distorta, form dense populations of unattached colonies on sand and rubble substrata. In the Galápagos, living C. (D.) distorta is found only at this single site, whereas populations of P. stellata are found throughout the Archipelago. Six cores dating to ~ 7700 yBP showed P. stellata to be dominant throughout the history of this isolated community, but C. (D.) distorta increased in abundance from ~ 2200 yBP and reached peak abundance between 1471 yBP and the present. The relative frequency of the two coral species may be linked to millennial-scale climatic variability, and this site may represent a refuge for C. (D.) distorta from unfavorable climatic fluctuations on millennial timescales. Our results demonstrate that some corals can persist in isolated populations for millennia