1,184 research outputs found
Some properties of canonical correlations and variates in infinite dimensions
AbstractIn this paper the notion of functional canonical correlation as a maximum of correlations of linear functionals is explored. It is shown that the population functional canonical correlation is in general well defined, but that it is a supremum rather than a maximum, so that a pair of canonical variates may not exist in the spaces considered. Also the relation with the maximum eigenvalue of an associated pair of operators and the corresponding eigenvectors is not in general valid. When the inverses of the operators involved are regularized, however, all of the above properties are restored. Relations between the actual population quantities and their regularized versions are also established. The sample functional canonical correlations can be regularized in a similar way, and consistency is shown at a fixed level of the regularization parameter
Global assessment of nitrogen deposition effects on terrestrial plant diversity : a synthesis
Atmospheric nitrogen (N) deposition is it recognized threat to plant diversity ill temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems. from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future. This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such its direct toxicity of nitrogen gases and aerosols long-term negative effects of increased ammonium and ammonia availability, soil-mediated effects of acidification, and secondary stress and disturbance are more ecosystem, and site-specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase. in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas. Critical loads are effect thresholds for N deposition. and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America. especially for the more sensitive ecosystem types. including several ecosystems of high conservation importance. The results of this assessment Show that the Vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and Southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe). and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted Studies are required in low background areas, especially in the G200 ecoregions
The Effect of Substituting High Oil Corn as a Replacement for Normal Corn in Nursery Pig Diets
The objective of this study was to determine the production and monetary effects of using High Oil Corn (HOC) in a nursery phase feeding program and monitor growth performance differences through marketing. Two groups of weaned crossbred pigs (n = 293 trial 1; n = 265 trial 2) were segregated by sex and weight into small, medium and heavy groups and allotted to 12 nursery pens. Pigs received one of two dietary treatments which included; a transitional phase I diet for 7 days; a commercial corn soy based phase II diet (NCII) for 14 days and a phase III diet (NCIII) for 7 days; a HOC soy based phase II diet for 21 days and the NCIII diet for 7 days. Body weight, Average daily feed intake and Gain/Feed (G/F) ratios were measured weekly during the nursery period. Pigs were transferred to a grow/finish barn on d 28 post-weaning. Body weight, Backfat (BF) and Longissimus Muscle Area (LMA) at the 10th and last ribs were ultrasonically evaluated 4 times prior to market. Average daily gain of nursery pigs on the three-phase NC diet was greater than pigs fed the HOC two-phase diet at d 21 post-weaning (p = .0034) and 28 post-weaning (p = .0128). ADG for heavy pigs was greater (p = .0001) than that of medium and lightweight pigs and no treatment�weight group interactions were observed (p = .2043). Pigs fed the three-phase diet had greater G/F ratios than pigs fed the HOC two-phase diet at d 21 (p = .0137) and 28 (p = .0134). LEA for pigs fed the three-phase diet was greater than pigs fed the HOC two-phase diet when measured on d 28 at the 10th (p = .0565) and last rib (p = .0370). Even though pigs were fed alike in the grow-finish period, ADG of pigs fed the three-phase nursery diet was greater (p = .0106) than that of pigs fed the HOC two-phase nursery diet. There were no differences in the predicted 114 kg weight (p = .2658). However, economic differences were noted for the two treatments with the HOC two-phase diet lowering the cost of production of marketed animals. There were no treatment differences for average daily lean growth per day (p = .8611) or percentage lean of carcasses (p = .2865). The results did not support removal of the transitional phase I diet and the substitution of HOC for NC in a phase II diet fed to nursery pigs for maximal nursery growth, nor was carcass composition of pigs at marketing adversely affected
A method for determining cross-measurements of motor neurons
This new triangulation technique allows the investigator to make cross-measurements of individual cells quickly and easily with a high degree of accuracy and reliability.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/42644/1/18_2005_Article_BF01927636.pd
An absolute determination of the 235U fission cross section at 964 keV
An absolute measurement of the 235U fission cross section has been carried out using a 24Na---Be photoneutron source with median neutron energy of 964 keV. A symmetric two-foil experiment was set up to measure the fission rate in a low-albedo laboratory, and variations in the source-to-foil spacing used to determine the room background. Fission fragments passing through a limited solid angle aperture were recorded from each foil by solid state tracketch techniques. The photoneutron source was calibrated after each run using the manganese bath method and the secondary national standard source NBS-II. A computed neutron source spectrum with 32 keV FWHM was derived by the Monte Carlo method and used in reducing the data to a cross section at 964 keV. The final value of 1.21 +/- 0.025 barns is absolute in that, except for small corrections, its determination was independent of any other cross section data.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22187/1/0000618.pd
Changes in soil carbon sequestration in <i>Pinus massoniana</i> forests along an urban-to-rural gradient of southern China
Urbanization is accelerating globally, causing a variety of environmental changes such as increases in air temperature, precipitation, atmospheric CO<sub>2</sub>, and nitrogen (N) deposition. However, the effects of these changes on forest soil carbon (C) sequestration remain largely unclear. Here, we used urban-to-rural environmental gradients in Guangdong Province, southern China, to address the potential effects of these environmental changes on soil C sequestration in <i>Pinus massoniana</i> forests. In contrast to our expectations and earlier observations, soil C content in urban sites was significantly lower than that in suburban and rural sites. Lower soil C pools in urban sites were correlated with a significant decrease in fine root biomass and a potential increase in soil organic C decomposition. Variation of soil C pools was also a function of change in soil C fractions. Heavy fraction C content in urban sites was significantly lower than that in suburban and rural sites. By contrast, light fraction C content did not vary significantly along the urban-to-rural gradient. Our results suggest that urbanization-induced environmental changes may have a negative effect on forest soil C in the studied region
Illegitimate recombination generates a class switch from C mu to C delta in an IgD-secreting plasmacytoma.
Psychometric Properties of the Hoarding Rating Scale-Interview
The present study tested the psychometric properties of an expanded version of the Hoarding Rating Scale (HRS-I), a semistructured interview for hoarding disorder (HD). Eighty-seven adults with HD and 44 healthy control (HC) participants were assessed using the HRS-I and completed a battery of self-report measures of HD severity, negative affect, and functional impairment. All interviews were audio recorded. From the HD participants, 21 were randomly selected for inter-rater reliability (IRR) analysis and 11 for test-retest reliability (TRR) analysis. The HRS-I showed excellent internal consistency (α = 0.87). IRR and TRR in the HD sample were good (intra-class coefficients = 0.81 and 0.85, respectively). HRS-I scores correlated strongly with scores on the self-report Saving Inventory-Revised (SI-R); partial correlations indicated that the HRS-I clutter, difficulty discarding, and acquiring items correlated significantly and at least moderately with corresponding SI-R subscales, when controlling for the other SI-R subscales. The HD group scored significantly higher on all items than did the HC group, with large effect sizes (d = 1.28–6.58). ROC analysis showed excellent sensitivity (1.00) and specificity (1.00) for distinguishing the HD and HC groups with a cutoff score of 11. Results and limitations are discussed in light of prior research
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