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

Some factors influencing populations of the European corn borer, Ostrinia nubilalis (Hubner) in the north central states: Resistance of corn, time of planting and weather conditions Part II, 1958-1962

A cooperative project was conducted by the agricultural experiment stations of Iowa, Minnesota and Ohio and the U. S. Department of Agriculture to study the effects of weather, planting date and resistant hybrids as factors influencing populations of the European com borer, Ostrinia nubilalis (Hübner). Identical studies were carried out at Ankeny, Iowa; Waseca, Minnesota; and Wooster, Ohio, during a 10-year period, 1953-1962. The first 4 years of the study (1953-56) were reported by Everett et al. (1958). The work reported herein is a companion bulletin to the Everett et al. (1958) publication and deals with the results of experiments conducted during 1958-1962. The experimental design was a randomized block, split plot with five replications. The whole plot treatments were four hybrid-planting date combinations consisting of early- or late-planting dates and susceptible or resistant hybrids. The subplot treatments consisted of a factorial arrangement of all possible combinations of three levels of infestation (zero, natural and natural + 3 egg masses) by first brood and the same three levels of infestation by second-brood borers. Temperature and rainfall records were kept at each of the three stations. Borer population and injury to the plant were recorded at the end of the first brood and in the fall. Yield data were collected

Massive Open Online Courses (MOOC) evaluation methods: protocol for a systematic review

BACKGROUND: Massive open online courses (MOOCs) have increased in popularity in recent years. They target a wide variety of learners and use novel teaching approaches, yet often exhibit low completion rates (10%). It is important to evaluate MOOCs to determine their impact and effectiveness, but little is known at this point about the methodologies that should be used for evaluation. OBJECTIVE: The purpose of this paper is to provide a protocol for a systematic review on MOOC evaluation methods. METHODS: We will use the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines for reporting this protocol. We developed a population, intervention, comparator, and outcome (PICO) framework to guide the search strategy, based on the overarching question, "What methods have been used to evaluate MOOCs?" The review will follow six stages: 1) literature search, 2) article selection, 3) data extraction, 4) quality appraisal, 5) data analysis, and 6) data synthesis. RESULTS: The systematic review is ongoing. We completed the data searches and data abstraction in October and November 2018. We are now analyzing the data and expect to complete the systematic review by March 2019. CONCLUSIONS: This systematic review will provide a useful summary of the methods used for evaluation of MOOCs and the strengths and limitations of each approach. It will also identify gaps in the literature and areas for future work. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/12087

Relaxation oscillations and negative strain rate sensitivity in the Portevin - Le Chatelier effect

A characteristic feature of the Portevin - Le Chatelier effect or the jerky flow is the stick-slip nature of stress-strain curves which is believed to result from the negative strain rate dependence of the flow stress. The latter is assumed to result from the competition of a few relevant time scales controlling the dynamics of jerky flow. We address the issue of time scales and its connection to the negative strain rate sensitivity of the flow stress within the framework of a model for the jerky flow which is known to reproduce several experimentally observed features including the negative strain rate sensitivity of the flow stress. We attempt to understand the above issues by analyzing the geometry of the slow manifold underlying the relaxational oscillations in the model. We show that the nature of the relaxational oscillations is a result of the atypical bent geometry of the slow manifold. The analysis of the slow manifold structure helps us to understand the time scales operating in different regions of the slow manifold. Using this information we are able to establish connection with the strain rate sensitivity of the flow stress. The analysis also helps us to provide a proper dynamical interpretation for the negative branch of the strain rate sensitivity.Comment: 7 figures, To appear in Phys. Rev.

High order amplitude equation for steps on creep curve

We consider a model proposed by one of the authors for a type of plastic instability found in creep experiments which reproduces a number of experimentally observed features. The model consists of three coupled non-linear differential equations describing the evolution of three types of dislocations. The transition to the instability has been shown to be via Hopf bifurcation leading to limit cycle solutions with respect to physically relevant drive parameters. Here we use reductive perturbative method to extract an amplitude equation of up to seventh order to obtain an approximate analytic expression for the order parameter. The analysis also enables us to obtain the bifurcation (phase) diagram of the instability. We find that while supercritical bifurcation dominates the major part of the instability region, subcritical bifurcation gradually takes over at one end of the region. These results are compared with the known experimental results. Approximate analytic expressions for the limit cycles for different types of bifurcations are shown to agree with their corresponding numerical solutions of the equations describing the model. The analysis also shows that high order nonlinearities are important in the problem. This approach further allows us to map the theoretical parameters to the experimentally observed macroscopic quantities.Comment: LaTex file and eps figures; Communicated to Phys. Rev.

Carcinogenic Parasite Secretes Growth Factor That Accelerates Wound Healing and Potentially Promotes Neoplasia

© 2015 Smout et al. Infection with the human liver fluke Opisthorchis viverrini induces cancer of the bile ducts, cholangiocarcinoma (CCA). Injury from feeding activities of this parasite within the human biliary tree causes extensive lesions, wounds that undergo protracted cycles of healing, and re-injury over years of chronic infection. We show that O. viverrini secreted proteins accelerated wound resolution in human cholangiocytes, an outcome that was compromised following silencing of expression of the fluke-derived gene encoding the granulin-like growth factor, Ov-GRN-1. Recombinant Ov-GRN-1 induced angiogenesis and accelerated mouse wound healing. Ov-GRN-1 was internalized by human cholangiocytes and induced gene and protein expression changes associated with wound healing and cancer pathways. Given the notable but seemingly paradoxical properties of liver fluke granulin in promoting not only wound healing but also a carcinogenic microenvironment, Ov-GRN-1 likely holds marked potential as a therapeutic wound-healing agent and as a vaccine against an infection-induced cancer of major public health significance in the developing world

Investigating behavioural and computational approaches for defining imprecise regions

People often communicate with reference to informally agreedplaces, such as “the city centre”. However, views of the spatial extent of such areas may vary, resulting in imprecise regions. We compare perceptions of Sheffield’s City Centre from a street survey to extents derived from various web-based sources. Such automated approaches have advantages of speed, cost and repeatability. We show that footprints from web sources are often in concordance with models derived from more labour-intensive methods. Notable exceptions however were found with sources advertising or selling residential property. Agreement between sources was measured by aggregating them to identify locations of consensus

Syntectonic mobility of supergene nickel ores of New Caledonia (Southwest Pacific). Evidence from faulted regolith and garnierite veins.

International audienceSupergene nickel deposits of New Caledonia that have been formed in the Neogene by weathering of obducted ultramafic rocks are tightly controlled by fracture development. The relationship of tropical weathering and tectonic structures, faults and tension gashes, have been investigated in order to determine whether fractures have play a passive role only, as previously thought; or alternatively, if brittle tectonics was acting together with alteration. From the observation of time-relationship, textures, and mineralogy of various fracture fills and fault gouges, it may be unambiguously established that active faulting has play a prominent role not only in facilitating drainage and providing room for synkinematic crystallisation of supergene nickel silicate, but also in mobilising already formed sparse nickel ore, giving birth to the very high grade ore nicknamed "green gold"