Arkansas Lepidoptera Survey: A Preliminary Check List of Arkansas Species

The mission of the Arkansas Lepidoptera Survey is to enhance the fundamental knowledge of butterflies, skippers, and moths in Arkansas. To achieve this mission, its objectives include developing a reference collection of Arkansas Lepidoptera and maintaining a current check list of present, historical and accidental species in Arkansas. The following list includes 1360 species representing 57 families. It was compiled from original field collecting, literature review, and analysis of museum specimens. The Arkansas Lepidoptera Survey established a reference collection of Arkansas butterflies, skippers and moths located in McEver Hall on the Arkansas Tech University campus. This collection currently contains 567 species representing 28 families

Evaluating the Fourth Amendment Exclusionary Rule: The Problem of Police Compliance with the Law

Part I of this article reviews background matters bearing on our research - in particular, we discuss the Court\u27s framework for analyzing exclusion as a deterrent safeguard, the research questions that need to be raised within that framework, and the research strategy we adopted in light of the Court\u27s approach to exclusion. Part II analyzes our findings on police knowledge of the rules of search and seizure. Part III analyzes our findings on officers\u27 willingness to obey the law. Part IV evaluates our findings in light of policy questions concerning the exclusionary rule. We consider whether the Court should retain the exclusionary rule or whether it should modify the rule by allowing for a good faith exception for officers\u27 mistakes in carrying out searches and seizures. We conclude that the exclusionary rule is the least undesirable remedy for nonegregious violations of the fourth amendment and that a general good faith exception to the rule should not be adopted

A Killer for Weeds in Soybeans

Timely use of the rotary hoe is an effective killer for weeds in soybeams. In this article, three Iowa State College scientists report directly to you on their tests comparing different weed-control methods

DDT Granules - A New Way to Kill Corn Borers

The European corn borer actually is a misnamed insect. At least two-thirds of the worm stage of its life is spent feeding on the surface of leaves and leaf sheaths. Only during the latter part of its life does it tunnel into the stalk and become a borer

Spatial and Temporal Variation in Aedes albopictus Prevalence Across Arkansas

Aedes albopictus is a well-known vector species of mosquito that is responsible for the transmission of many arboviruses such as Zika, chikungunya, and dengue. The objective of this study was to quantify spatial and temporal variation of Ae. albopictus prevalence in Arkansas. We used egg abundance as a proxy for mosquito prevalence. Across 2 years, we worked with the Arkansas Department of Health to collect mosquito eggs using oviposition traps. Eggs were desiccated, counted, and later rehydrated in rearing chambers and raised through adulthood for species determination (\u3e99% Ae. albopictus). We determined mean egg abundance by month, year, and latitude, and mapped egg counts using graduated colors to visually display county-specific patterns. Egg abundance was typically low in spring, peaked in late summer, and steadily declined through fall. We observed north-south differences in egg abundance, though the latitude of peak abundance varied across years and throughout the seasons. This research reveals temporal variation and spatial hotspots in Ae. albopictus prevalence across the state of Arkansas and highlights existing gaps that should be targeted by future sampling

Single-molecule analysis of RAG-mediated V(D)J DNA cleavage

The recombination-activating gene products, RAG1 and RAG2, initiate V(D)J recombination during lymphocyte development by cleaving DNA adjacent to conserved recombination signal sequences (RSSs). The reaction involves DNA binding, synapsis, and cleavage at two RSSs located on the same DNA molecule and results in the assembly of antigen receptor genes. We have developed single-molecule assays to examine RSS binding by RAG1/2 and their cofactor high-mobility group-box protein 1 (HMGB1) as they proceed through the steps of this reaction. These assays allowed us to observe in real time the individual molecular events of RAG-mediated cleavage. As a result, we are able to measure the binding statistics (dwell times) and binding energies of the initial RAG binding events and characterize synapse formation at the single-molecule level, yielding insights into the distribution of dwell times in the paired complex and the propensity for cleavage on forming the synapse. Interestingly, we find that the synaptic complex has a mean lifetime of roughly 400 s and that its formation is readily reversible, with only ∼40% of observed synapses resulting in cleavage at consensus RSS binding sites

Assessing what is needed to resolve a molecular phylogeny: simulations and empirical data from emydid turtles

<p>Abstract</p> <p>Background</p> <p>Phylogenies often contain both well-supported and poorly supported nodes. Determining how much additional data might be required to eventually recover most or all nodes with high support is an important pragmatic goal, and simulations have been used to examine this question. Most simulations have been based on few empirical loci, and suggest that well supported phylogenies can be determined with a very modest amount of data. Here we report the results of an empirical phylogenetic analysis of all 10 genera and 25 of 48 species of the new world pond turtles (family Emydidae) based on one mitochondrial (1070 base pairs) and seven nuclear loci (5961 base pairs), and a more biologically realistic simulation analysis incorporating variation among gene trees, aimed at determining how much more data might be necessary to recover weakly-supported nodes with strong support.</p> <p>Results</p> <p>Our mitochondrial-based phylogeny was well resolved, and congruent with some previous mitochondrial results. For example, all genera, and all species except <it>Pseudemys concinna</it>, <it>P. peninsularis</it>, and <it>Terrapene carolina </it>were monophyletic with strong support from at least one analytical method. The Emydinae was recovered as monophyletic, but the Deirochelyinae was not. Based on nuclear data, all genera were monophyletic with strong support except <it>Trachemys</it>, and all species except <it>Graptemys pseudogeographica</it>, <it>P. concinna</it>, <it>T. carolina</it>, and <it>T. coahuila </it>were monophyletic, generally with strong support. However, the branches subtending most genera were relatively short, and intergeneric relationships within subfamilies were mostly unsupported.</p> <p>Our simulations showed that relatively high bootstrap support values (i.e. ≥ 70) for all nodes were reached in all datasets, but an increase in data did not necessarily equate to an increase in support values. However, simulations based on a single empirical locus reached higher overall levels of support with less data than did the simulations that were based on all seven empirical nuclear loci, and symmetric tree distances were much lower for single versus multiple gene simulation analyses.</p> <p>Conclusion</p> <p>Our empirical results provide new insights into the phylogenetics of the Emydidae, but the short branches recovered deep in the tree also indicate the need for additional work on this clade to recover all intergeneric relationships with confidence and to delimit species for some problematic groups. Our simulation results suggest that moderate (in the few-to-tens of kb range) amounts of data are necessary to recover most emydid relationships with high support values. They also suggest that previous simulations that do not incorporate among-gene tree topological variance probably underestimate the amount of data needed to recover well supported phylogenies.</p

Changes in gross oxygen production, net oxygen production, and air-water gas exchange during seasonal ice melt in Whycocomagh Bay, a Canadian estuary in the Bras d\u27Or Lake system

Sea ice is an important control on gas exchange and primary production in polar regions. We measured net oxygen production (NOP) and gross oxygen production (GOP) using near-continuous measurements of the O2∕Ar gas ratio and discrete measurements of the triple isotopic composition of O2, during the transition from ice-covered to ice-free conditions, in Whycocomagh Bay, an estuary in the Bras d\u27Or Lake system in Nova Scotia, Canada. The volumetric gross oxygen production was 5.4+2.8-1.6 role= presentation \u3e5.4+2.8−1.6 mmol O2 m−3 d−1, similar at the beginning and end of the time series, and likely peaked at the end of the ice melt period. Net oxygen production displayed more temporal variability and the system was on average net autotrophic during ice melt and net heterotrophic following the ice melt. We performed the first field-based dual tracer release experiment in ice-covered water to quantify air–water gas exchange. The gas transfer velocity at \u3e90 % ice cover was 6 % of the rate for nearly ice-free conditions. Published studies have shown a wide range of results for gas transfer velocity in the presence of ice, and this study indicates that gas transfer through ice is much slower than the rate of gas transfer through open water. The results also indicate that both primary producers and heterotrophs are active in Whycocomagh Bay during spring while it is covered in ice

The Gas Transfer through Polar Sea Ice Experiment: Insights into the Rates and Pathways that Determine Geochemical Fluxes

Sea ice is a defining feature of the polar marine environment. It is a critical domain for marine biota and it regulates ocean-atmosphere exchange, including the exchange of greenhouse gases such as CO2 and CH4. In this study, we determined the rates and pathways that govern gas transport through a mixed sea ice cover. N2O, SF6, 3He, 4He, and Ne were used as gas tracers of the exchange processes that take place at the ice-water and air-water interfaces in a laboratory sea ice experiment. Observation of the changes in gas concentrations during freezing revealed that He is indeed more soluble in ice than in water; Ne is less soluble in ice, and the larger gases (N2O and SF6) are mostly excluded during the freezing process. Model estimates of gas diffusion through ice were calibrated using measurements of bulk gas content in ice cores, yielding gas transfer velocity through ice (kice) of ∼5 × 10−4 m d−1. In comparison, the effective air-sea gas transfer velocities (keff) ranged up to 0.33 m d−1 providing further evidence that very little mixed-layer ventilation takes place via gas diffusion through columnar sea ice. However, this ventilation is distinct from air-ice gas fluxes driven by sea ice biogeochemistry. The magnitude of keff showed a clear increasing trend with wind speed and current velocity beneath the ice, as well as the combination of the two. This result indicates that gas transfer cannot be uniquely predicted by wind speed alone in the presence of sea ice