Multidimensional Liquid Chromatography Separations

Many mixtures important to research consist of hundreds or even thousands of individual components of interest. These types of mixtures are far too complex to separate by a single chromatographic dimension in any reasonable amount of time. However, if a multidimensional approach is used, where a complex mixture is separated by an initial dimension, simpler fractions of that separation are collected and each of those fractions are analyzed individually, highly complex mixtures can be resolved in relatively short amounts of time. This dissertation serves as a guide to multidimensional chromatography, in particular, two-dimension liquid chromatography. There are many aspects of multidimensional separations that have been investigated to show its aspects, drawbacks and potential ability to separate highly complex mixtures. Measurements for the performance of multidimensional chromatography, the effects of the first and subsequent dimensions and the approaches to pairing dimensions are shown with experimental examples. Fundamental and practical features of multidimensional chromatography are explained as well as theoretical discussions on current and future multidimensional chromatography performance. Experimentally, very high peak capacities were obtained (ca. 7000) and an algorithm to predict how to best optimize a two-dimensional separation based on the time used and performance was created for designing experiments

ECONOMIC ANALYSIS OF TEMIK ON CITRUS IN THE INDIAN RIVER AREA IN SOUTHEASTERN FLORIDA

Temik [R](aldicarb) is a pesticide labeled for use on several citrus crops to control rust mite, whitefly, nematode and brown citrus aphid pests. Analysis of previous research experiments indicates that this pesticide is beneficial to both orange and grapefruit production and that both cost savings and higher yields can be experienced in many types of groves. Actual grove data shows that net returns for mature grapefruit that receive Temik [R] can be $500 per acre greater than net returns for identical acreage that uses other pest control options. Also, based on grove reset data it is shown that with an application of Temik [R] the resulting increased yields for three-year-old trees more than cover the additional cost of applying the Temik [R].mature citrus, resets, revenue-cost, net return, grapefruit, Crop Production/Industries,

Exploring the relationship between adiposity and fitness in young children

PURPOSE: High levels of cardiorespiratory fitness (CRF) may attenuate the association between excessive adiposity and the risks of cardiovascular and metabolic disease. The purpose of this study was to stratify children according to their BMI and adiposity (body fat percentage, BF%) and compare levels of CRF across subgroups. METHODS: This prospective cohort study comprises a cross-sectional and longitudinal analyses of data collected at baseline (n=641) and two years later (n=579) on children (7.4-11.6y) attending public school in Denmark. Levels of CRF were measured using the Andersen test, while BF% was measured by dual-energy x-ray absorptiometry (DXA). RESULTS: There were 560 (87.4%) children classified as normal weight according to BMI at baseline, of which 46 (7.4%) were identified as having excessive BF%. These children had significantly lower CRF (mean [95% Confidence Interval]: −63.1m [−100.2,-25.9]) than children with normal BMI and normal BF%; and the effect of BF% on CRF was significantly worse in boys than girls. Overweight children with high BF%, had significantly lower prospective (2 years) CRF levels (−34.4m [−58.0,-10.7]) than children with normal BMI and BF%. Though children who improved their BMI and/or BF% classification over the two year period achieved CRF levels (8.9m [−30.2,47.9]) which were comparable to children with normal BMI and BF% at both measurement time points. CONCLUSION: The CRF levels in children are impacted by BMI and BF%, although BF% appears to play a greater role. This association between BF% and CRF is sex-dependent, with CRF levels in boys being impacted to a greater extent by BF%. Children identified as ‘normal weight’ by BMI but presenting with excessive BF% had significantly lower CRF than ‘normal weight’ children with low BF%

Big Sagebrush Response to One-Way and Two-Way Chaining in Southeastern Utah

A decadent, mixed stand of Wyoming big sagebrush, Artemisia tridentata wyomingensis, and mountain big sagebrush, Artemisia tridentata vaseyana, located north of Cisco, Utah, was subjected to one-way and two-way chaining treatments in November 1987. The effect of the treatments on plant community characteristics and shrub vigor was documented over a 3-year period. Stand density was reduced 60 percent on sites chained two ways and 43 percent on sites chained over once. Shrubs on one-way chained sites produced more leader growth in 1989 and 1990 than those on untreated sites or sites chained two ways. Browse production on one-way chained sites surpassed that of untreated sites and two-way chained sites by 140 percent and 350 percent, respectively. Over the short term, a one-way chaining was shown to be an effective method for improving sagebrush vigor and production on a critical mule deer winter range

Bilingualism Is Associated with a Delayed Onset of Dementia but Not with a Lower Risk of Developing it: a Systematic Review with Meta-Analyses.

Some studies have linked bilingualism with a later onset of dementia, Alzheimer's disease (AD), and mild cognitive impairment (MCI). Not all studies have observed such relationships, however. Differences in study outcomes may be due to methodological limitations and the presence of confounding factors within studies such as immigration status and level of education. We conducted the first systematic review with meta-analysis combining cross-sectional studies to explore if bilingualism might delay symptom onset and diagnosis of dementia, AD, and MCI. Primary outcomes included the age of symptom onset, the age at diagnosis of MCI or dementia, and the risk of developing MCI or dementia. A secondary outcome included the degree of disease severity at dementia diagnosis. There was no difference in the age of MCI diagnosis between monolinguals and bilinguals [mean difference: 3.2; 95% confidence intervals (CI): -3.4, 9.7]. Bilinguals vs. monolinguals reported experiencing AD symptoms 4.7 years (95% CI: 3.3, 6.1) later. Bilinguals vs. monolinguals were diagnosed with dementia 3.3 years (95% CI: 1.7, 4.9) later. Here, 95% prediction intervals showed a large dispersion of effect sizes (-1.9 to 8.5). We investigated this dispersion with a subgroup meta-analysis comparing studies that had recruited participants with dementia to studies that had recruited participants with AD on the age of dementia and AD diagnosis between mono- and bilinguals. Results showed that bilinguals vs. monolinguals were 1.9 years (95% CI: -0.9, 4.7) and 4.2 (95% CI: 2.0, 6.4) older than monolinguals at the time of dementia and AD diagnosis, respectively. The mean difference between the two subgroups was not significant. There was no significant risk reduction (odds ratio: 0.89; 95% CI: 0.68-1.16) in developing dementia among bilinguals vs. monolinguals. Also, there was no significant difference (Hedges' g = 0.05; 95% CI: -0.13, 0.24) in disease severity at dementia diagnosis between bilinguals and monolinguals, despite bilinguals being significantly older. The majority of studies had adjusted for level of education suggesting that education might not have played a role in the observed delay in dementia among bilinguals vs. monolinguals. Although findings indicated that bilingualism was on average related to a delayed onset of dementia, the magnitude of this relationship varied across different settings. This variation may be due to unexplained heterogeneity and different sources of bias in the included studies. Registration: PROSPERO CRD42015019100

Controls on the 87Sr/86Sr ratios of carbonates in the Garhwal Himalaya, Headwaters of the Ganges

The episodic variation of the seawater 87Sr/86Sr ratio has been attributed to either variations in the Sr flux or the Sr-isotopic composition of the riverine-dissolved load derived from weathering of the continental crust. The discovery that Himalayan rivers are characterized by high concentrations of dissolved Sr concentrations with high 87Sr/86Sr ratios has raised the possibility that collisional orogens play a critical role in moderating the variations in seawater 87Sr/86Sr ratios. Here we describe Himalayan carbonates and calc-silicates from Garhwal, the headwaters of the Ganges, with extreme 87Sr/86Sr ratios (>1.0). Elevated Sr-isotope ratios result from exchange with Rb-rich silicate material during both Himalayan and pre-Himalayan metamorphic episodes, and the carbonates contribute a significant fraction to the Ganges 87Sr flux. Particularly elevated 87Sr/86Sr ratios are found in calc-silicates from the Deoban Formation of the Lesser Himalaya. A detailed traverse of shales and calc-silicates from this unit confirms that carbonate horizons have increased 87Sr/86Sr ratios as a result of isotopic exchange over length scales of 1030 cm. We conclude that metamorphism of carbonates may cause elevation of their 87Sr/86Sr ratios and that uplift of metamorphosed carbonates may be a consequence of collisional orogens, which contributes to the elevation of seawater 87Sr/86Sr ratios

Coincident Measurement of the Energy Spectra of Doppler-Shifted Annihilation Gamma Quanta and Positron-Induced Secondary Electrons

Preliminary results are presented from a new positron beam system currently under development at the University of Texas at Arlington for the coincident energy measurement of Doppler-shifted annihilation quanta and positron-induced Auger electrons. We report data based on an analysis of the pulses resulting from the detection of positron induced secondary electrons by a micro-channel plate detector in coincidence with the pulses resulting from the detection of associated annihilation gamma rays in a NaI(Tl) gamma detector.Comment: Presented at 18th International Conference on Positron Annihilation, August 19-24, 2018 | Orlando, USA. The following article has been accepted by AIP Conference Proceedings. After it is published, it will be found at https://aip.scitation.org/journal/ap

European Corn Borer, Ostrinia nubilalis (Hbn.) Populations in Field Corn, Zea mays (L.) in the North Central United States

A long-range study of the annual changes in corn borer populations in the North Central States was started in Minnesota, Iowa, Kansas and Nebraska in 1955 and in Missouri and Ohio in 1956. This investigation was a phase of a broader Regional Project, NC-20, entitled Factors Influencing Corn Borer Populations and was undertaken to measure by standardized procedures the seasonal changes in abundance of the European corn borer, Ostrinia nubilalis (Hbn.), under cropping procedures in different locations within, the North Central States. Much valuable information has been accumulated on the abundance and effects of various physical and biotic factors on corn borer populations. Results obtained from 1955 through 1959 are summarized in a regional publication (Chiang et al. 1961). The present compilation and summary is offered as a companion bulletin containing data for the years 1960 through 1964. Although the primary purpose of the present bulletin is to present results for the 1960 to 1964 period, it seemed pertinent to include statements of comparison with the preceding 5-year\u27s work and to analyze in a rather gross way certain aspects of the population changes for the entire 10-year period. Studies of this nature are long-time projects requiring many years of work in order to evaluate population fluctuations and factors influencing them. Hence the examination of the recent 5-year period becomes more meaningful when compared with the previous 5-year period or when considered as a single 10-year period

Empathic Accuracy in Female Adolescents with Conduct Disorder and Sex Differences in the Relationship Between Conduct Disorder and Empathy

Funder: Economic and Social Research Council; doi: http://dx.doi.org/10.13039/501100000269Abstract: Research on empathy in youth with Conduct Disorder (CD) has primarily focused on males, with the few studies that have investigated empathy in females relying on questionnaire measures. Our primary aim was to investigate whether females with CD show empathy deficits when using a more ecologically-valid task. We used an empathic accuracy (EA) paradigm that involved watching videos of actors recalling emotional experiences and providing continuous ratings of emotional intensity (assessing EA), naming the emotion expressed (emotion recognition), and reporting whether they shared the emotion expressed (affective empathy). We compared 23 females with CD and 29 typically-developing (TD) adolescents aged 13–18 years. The CD sample was divided into subgroups with higher (CD/CU+) versus lower (CD/CU−) levels of callous-unemotional traits. Females with CD did not differ from TD females in EA or emotion recognition but exhibited reduced affective empathy responses (ps < 0.01, rs ≥ 0.39). The CD/CU+ and CD/CU− subgroups did not differ on any empathy measure. We also assessed for sex differences in CD-empathy associations by comparing the present data with archive data from males. CD adolescents exhibited impairments in EA relative to their TD counterparts overall (p < 0.05, ηp2 = 0.06), but there was no sex-by-diagnosis interaction. While females with CD were only impaired in affective empathy, males with CD exhibited emotion recognition and affective empathy deficits. This study demonstrates that females with CD show relatively specific impairments in affective empathy on an ecologically-valid task, whereas males with CD display more global empathic difficulties