Effects of Previous Hybrid on Corn Yields the Following Year

Approximately 25% of Iowa\u27s annual 12.5 million acres of corn is grown where corn was grown the previous year. With adequate N fertilizer, corn following corn usually yields less than corn following soybeans or some other crop. The magnitude of this yield reduction usually is about 10%, but it varies between fields, locations and years. During 1988 in southeastern Iowa, farmers and researchers reported yield differences as great as 100 bufacre between the yield of corn after soybeans and corn after corn. There are many possible explanations for the rotation effect such as differences in residual soil moisture, soil nitrogen, soil compaction or structure, soil microflora, corn root worm and diseases. Sometimes the yield difference can be related to one or more of these explanations, but not with any consistency. It becomes impossible to characterize the interaction of these various factors with each other in highly variable field environments. Many studies have been conducted attempting to relate substances left by corn which is toxic to the following corn crop or stimulatory substances left by soybeans; this phenomenon of one crop affecting another crop by substances left in the environment is called allelopathy (Anderson et al. 1988)

Failure of a Pipeline in an 800-year Old Debris Fill

In June of 1994 a 20-m section of 1.4-m diameter, restrained-joint, ductile iron pipe failed during construction of a new section of water pipeline for the city of Cairo in the Arab Republic of Egypt. The failure occurred in an area where the pipe was supported on piles, and compacted silica sand was used as side support for the pipe. Soil above the crown of the failed section of pipe was 6 m or more in thickness. Results of a detailed review of the failure revealed that a number of unique and related factors apparently caused the failure. The most significant of these causes was the native soil surrounding the pipeline, which was formed from an accumulation of 800 years of building and construction debris. At the location of the failure the debris was in excess of 15-m thick. When subjected to water at this location, this debris underwent significant settlement, which eventually led to loss in side support for the pipeline. To repair the pipeline and to avoid future similar failures, a utilidor was used to protect the pipeline in areas where overburden thickness was greater than 4.5 m, and a pipe encasement was used where the overburden thickness was less

Organic Agriculture in the landscape of sustainability initiatives

Organic is not the only initiative with the aim of improving sustainability in agriculture. There is a wide array of approaches, perspectives, priorities and levels of ambition. Certain initiatives are seen as complimentary to Organic Agriculture and use it as a basis. Others are viewed as followers, competitors or – due to lower sustainability requirements – even as "greenwashers". As not all assessments of standards and impacts recognize a leading position for Organic farming, there is room for improvement

The Sensitivity of Auditory-Motor Representations to Subtle Changes in Auditory Feedback While Singing

Singing requires accurate control of the fundamental frequency (F0) of the voice. This study examined trained singers’ and untrained singers’ (nonsingers’) sensitivity to subtle manipulations in auditory feedback and the subsequent effect on the mapping between F0 feedback and vocal control. Participants produced the consonant-vowel /ta/ while receiving auditory feedback that was shifted up and down in frequency. Results showed that singers and nonsingers compensated to a similar degree when presented with frequency-altered feedback (FAF); however, singers’ F0 values were consistently closer to the intended pitch target. Moreover, singers initiated their compensatory responses when auditory feedback was shifted up or down 6 cents or more, compared to nonsingers who began compensating when feedback was shifted up 26 cents and down 22 cents. Additionally, examination of the first 50 ms of vocalization indicated that participants commenced subsequent vocal utterances, during FAF, near the F0 value on previous shift trials. Interestingly, nonsingers commenced F0 productions below the pitch target and increased their F0 until they matched the note. Thus, singers and nonsingers rely on an internal model to regulate voice F0, but singers’ models appear to be more sensitive in response to subtle discrepancies in auditory feedback

Assessing ternary materials for fluoride-ion batteries

Although lithium-ion batteries have transformed energy storage, there is a need to develop battery technologies with improved performance. Fluoride-ion batteries (FIBs) may be promising alternatives in part due to their high theoretical energy density and natural elemental abundance. However, electrode materials for FIBs, particularly cathodes, have not been systematically evaluated, limiting rapid progress. Here, we evaluate ternary fluorides from the Materials Project crystal structure database to identify promising cathode materials for FIBs. Structures are further assessed based on stability and whether fluorination/defluorination occurs without unwanted disproportionation reactions. Properties are presented for pairs of fluorinated/defluorinated materials including theoretical energy densities, cost approximations, and bandgaps. We aim to supply a dataset for extracting property and structural trends of ternary fluoride materials that may aid in the discovery of next-generation battery materials

Severity of back pain may influence choice and order of practitioner consultations across conventional, allied and complementary health care: A cross-sectional study of 1851 mid-age Australian women

© 2016 The Author(s). Background: Back pain is a common, disabling and costly disorder for which patients often consult with a wide range of health practitioners. Unfortunately, no research to date has directly examined the association between the severity of back pain and back pain sufferers' choice of whom and in what order to consult different health practitioners. Methods: This is a sub-study of the large nationally representative Australian Longitudinal Study on Women's Health (ALSWH). The mid-age cohort women (born 1946-51, n = 13,715) of the ALSWH were recruited from the Australian national Medicare database in 1996. These women have been surveyed six time, with survey 6 being conducted in 2010 (n = 10,011). Mid-age women (n = 1851) who in 2010 had sought help from a health care practitioner for their back pain were mailed a self-report questionnaire targeting their previous 12 months of health services utilisation, health status and their levels of back pain intensity. Results: A total of 1620 women were deemed eligible and 1310 (80.9 %) returned completed questionnaires. Mid-age women with back pain visited various conventional, allied health and CAM practitioners for care: 75.6 % consulted a CAM practitioner; 58.4 % consulted a medical doctor; and 54.2 % consulted an allied health practitioner. Women with the most severe back pain sought conventional care from a general practitioner, and those who consulted a general practitioner first had more severe back pain than those who consulted another practitioner first. Following the general practitioner visit, the women with more severe back pain were more likely to be referred to a conventional specialist, and those with less severe back pain were more likely to be referred to a physiotherapist. Conclusions: Our findings suggest that women with more severe back pain are likely to visit a conventional practitioner first, whereas women with less severe back pain are likely to explore a range of treatment options including CAM practitioners. The improvement of back pain over time following the various possible sequencing of consultations with different types of health practitioners is a topic with implications for ensuring safe and effective back pain care and worthy of further detailed investigation

The effectiveness of complementary manual therapies for pregnancy-related back and pelvic pain A systematic review with meta-analysis

© 2016 the Author(s). Published by Wolters Kluwer Health, Inc. All rights reserved. Background: Low back pain and pelvic girth pain are common in pregnancy and women commonly utilize complementary manual therapies such as massage, spinal manipulation, chiropractic, and osteopathy to manage their symptoms. Objective: The aim of this systematically review was to critically appraise and synthesize the best available evidence regarding the effectiveness of manual therapies for managing pregnancy-related low back and pelvic pain. Methods: Seven databases were searched from their inception until April 2015 for randomized controlled trials. Studies investigating the effectiveness of massage and chiropractic and osteopathic therapies were included. The study population was pregnant women of any age and at any time during the antenatal period. Study selection, data extraction, and assessment of risk of bias were conducted by 2 reviewers independently, using the Cochrane tool. Separate meta-analyses were conducted to compare manual therapies to different control interventions. Results: Out of 348 nonduplicate records, 11 articles reporting on 10 studies on a total of 1198 pregnant women were included in this meta-analysis. The therapeutic interventions predominantly involved massage and osteopathic manipulative therapy. Metaanalyses found positive effects for manual therapy on pain intensity when compared to usual care and relaxation but not when compared to sham interventions. Acceptability did not differ between manual therapy and usual care or sham interventions. Conclusions: There is currently limited evidence to support the use of complementary manual therapies as an option for managing low back and pelvic pain during pregnancy. Considering the lack of effect compared to sham interventions, further high-quality research is needed to determine causal effects, the influence of the therapist on the perceived effectiveness of treatments, and adequate dose-response of complementary manual therapies on low back and pelvic pain outcomes during pregnancy

High-throughput discovery of fluoride-ion conductors via a decoupled, dynamic, and iterative (DDI) framework

Fluoride-ion batteries are a promising alternative to lithium-ion batteries with higher theoretical capacities and working voltages, but they have experienced limited success due to the poor ionic conductivities of known electrolytes and electrodes. Here, we report a high-throughput computational screening of 9747 fluoride-containing materials in search of fluoride-ion conductors. Via a combination of empirical, lightweight DFT, and nudged elastic band (NEB) calculations, we identified >10 crystal systems with high fluoride mobility. We applied a search strategy where calculations are performed in any order (decoupled), computational resources are reassigned based on need (dynamic), and predictive models are repeatedly updated (iterative). Unlike hierarchical searches, our decoupled, dynamic, and iterative framework (DDI) began by calculating high-quality barrier heights for fluoride-ion mobility in a large and diverse group of materials. This high-quality dataset provided a benchmark against which a rapid calculation method could be refined. This accurate method was then used to measure the barrier heights for 6797 fluoride-ion pathways. The final dataset has allowed us to discover many fascinating, high-performance conductors and to derive the design rules that govern their performance. These materials will accelerate experimental research into fluoride-ion batteries, while the design rules will provide an improved foundation for understanding ionic conduction

Effect of substrate thermal resistance on space-domain microchannel

In recent years, Fluorescent Melting Curve Analysis (FMCA) has become an almost ubiquitous feature of commercial quantitative PCR (qPCR) thermal cyclers. Here a micro-fluidic device is presented capable of performing FMCA within a microchannel. The device consists of modular thermally conductive blocks which can sandwich a microfluidic substrate. Opposing ends of the blocks are held at differing temperatures and a linear thermal gradient is generated along the microfluidic channel. Fluorescent measurements taken from a sample as it passes along the micro-fluidic channel permits fluorescent melting curves to be generated. In this study we measure DNA melting temperature from two plasmid fragments. The effects of flow velocity and ramp-rate are investigated, and measured melting curves are compared to those acquired from a commercially available PCR thermocycler