For multivariate statistical process control with individual observations the usually recommended procedure in retrospective phase is Hotelling's T2 chart. All are pooled to estimate mean vector and covariance matrix. An out-of-control signal results if value of any observation exceeds an upper limit. We show this not effective detecting a shift because matrix badly estimated. Somewhat surprisingly, probability decreases increasingly severe shifts vector. compare several alternative methods...

Soybean, Glycine max (L.) Merr. cv Essex, plants were grown in the field a 2 x factorial design, under ambient and supplemental levels of ultraviolet-B (UV-B) radiation (supplemental daily dose 5.1 effective kilojoules per square meter) either well-watered or subjected to drought. Soil water potentials reduced -2.0 megapascals by exclusion natural precipitation drought plots maintained at approximately -0.5 megapascal irrigation plots. Plant growth gas exchange characteristics affected both...

We investigate the effects of non-normality on statistical performance multivariate exponentially weighted moving average (MEWMA) control chart, and its special case, Hotelling's chi-squared when applied to individual observations monitor mean vector a process variable. show that chart is highly sensitive non-normality. argue most departures from normality with (subgroups size one). observations, therefore, by extension, subgroups any size, MEWMA can be designed robust very effective at...

Two soybean [ Glycine max (L.) Merr.] cultivars, Essex and Williams, were grown in the field for 6 consecutive seasons under ambient supplemental levels of ultravio‐Set‐B radiation to determine potential alterations yield or seed quality with a reduction stratospheric ozone column. The UV‐B fluences simulated 16 25% depletion. data presented here represent first experiment conducted over multiple which assesses effects increased on yield. Overall, cultivar was found be sensitive (yield...

Wheat (Triticum aestivum L. cv Bannock), rice (Oryza sativa IR-36), and soybean (Glycine max [L.] Merr Essex) were grown in a factorial greenhouse experiment to determine if CO2-induced increases photosynthesis, biomass, yield are modified by ultraviolet (UV)-B radiation corresponding stratospheric ozone depletion. The experimental conditions simulated were: (a) an increase CO2 concentration from 350 650 microliters per liter; (b) UV-B 10% depletion at the equator; (c) b combination. Seed...

For honey bees (Apis mellifera), colony maintenance and growth are highly dependent on worker foragers obtaining sufficient resources from flowering plants year round. Despite the importance of floral diversity for proper bee nutrition, urban development has drastically altered resource availability these important pollinators. Therefore, understanding foraged by in urbanized areas is key to identifying promoting that enhance health those environments. In this study, we identified pollen...

Seeds from four plant pairs collected contrasting elevations in Hawaii were grown greenhouses at the University of Maryland UV‐B radiation levels that approximated a 20% and 40% stratospheric ozone depletion anticipated sea level Maui. In general, increases resulted earlier reproductive effort, increased dark respiration maintenance relative water content (RWC), photosynthesis, apparent quantum efficiency (AQE) plants higher where natural is already high. contrast, low elevational ranges...

Interest in the potential consequences of stratospheric ozone depletion has led to numerous studies that have evaluated effects ultraviolet‐B (UV‐B) radiation on plant growth and productivity. However, few been conducted plants from natural ecosystems. Differences solar UV‐B along latitudinal or elevational gradients may resulted diverse habitats developing contrasting sensitivities radiation. In this study, seeds were collected a 3,000‐m gradient Hawaii then germinated grown an unshaded...

ABSTRACT Better understanding of crop responses to projected changes in climate is an important requirement. An experiment was conducted sunlit, controlled environment chambers known as soil–plant–atmosphere–research units determine the interactive effects atmospheric carbon dioxide concentration [CO 2 ] and ultraviolet‐B (UV‐B) radiation on cotton ( Gossypium hirsutum L.) growth, development leaf photosynthetic characteristics. Six treatments were used, comprising two levels (360 720 µ mol...

Ten conifer species were grown in an unshaded greenhouse at the University of Maryland under 3 levels biologically effective ultraviolet‐B radiation. Ultraviolet‐B radiation was supplied by Westinghouse FS‐40 sunlamps and daily doses 0, 12.4, 19.1 kJ m –2 . During irradiation period, seedling growth development stress symptoms monitored. After 22 weeks irradiation, seedlings harvested morphological characteristics analyzed. Visual included needle discoloration stunting three ten tested....

One‐year old loblolly pine ( Pinus taeda L.) seedlings were grown in an unshaded greenhouse for 7 months under 4 levels of ultraviolet‐B (UV‐B) radiation simulating stratospheric ozone reductions 16, 25 and 40% included a control with no UV‐B radiation. Periodic measurements made growth gas exchange characteristics needle chlorophyll UV‐B‐absorbing‐compound concentrations. The effectiveness on seedling physiology varied the irradiance level. Seedlings receiving lowest supplemental showed...

Leaf‐level measurements of gas exchange, chemistry, morphology, and spectral optical properties were acquired at the five instrumented tower sites during three 1994 growing season intensive field campaigns (IFCs) conducted near Prince Albert, Saskatchewan, as part Boreal Ecosystem‐Atmosphere Study (BOREAS). Stands included old young aspen (OA, YA) associated with hazelnut shrub, jack pine (OJP, YJP) stands, an black spruce (OBS) stand; white (at understory herb (dogbane, OJP) also examined....

Absorption or screening of ultraviolet‐B (UV‐B) radiation by the epidermis may be an important protective method which plants avoid damage upon exposure to potentially harmful UV‐B radiation. In present study we examined relationships among epidermal effectiveness, concentration UV‐absorbing compounds, anatomy and growth responses in seedlings loblolly pine ( Pinus taeda L.) sweetgum Liquidambar styraciflua L.). Seedlings each species were grown a greenhouse at University Maryland under...

A preliminary control chart based on individual observations for detecting a shift in either the mean or variance both is developed from likelihood ratio test. The advantages over use of X and moving range are improved detection sustained shifts, addition to diagnostic information indicating multiple shifts whether an out-of-control signal primarily due combination. Approximate limits, determined simulation, given proposed chart.

We examined the effect of supplemental UV-B radiation (290-320 nm) on photosynthetic characteristics different aged needles 3-year-old, field-grown loblolly pine (Pinus taeda L.). Needles in four age classes were examined: I, most recently fully expanded, year 3; II, first flush, III, final 2; and IV, oldest still present, 2. Enhanced caused a statistically significant decrease (6%) ratio variable to maximum fluorescence (F(v)/F(m)) following dark adaptation only from youngest class,...

ABSTRACT The effects of ultraviolet‐B (UV‐B between 290 and 320 nm) on photosynthesis growth characteristics were investigated in field grown cassava ( Manihot esculentum Crantz). Plants at ambient plus a 5.5kJ m −2 d −1 supplementation UV‐B radiation for 95 d. supplemental fluence used this experiment simulated 15% depletion stratospheric ozone the equator (0°N). Carbon dioxide exchange, oxygen evolution, ratio variable to maximum fluorescence (F v /F ) determined fully expanded leaves...

In the historical (or retrospective or Phase I) multivariate data analysis, choice of estimator for variance–covariance matrix is crucial to successfully detecting presence special causes variation. For case individual observations, compounded by lack rational subgroups observations with same distribution. Other research has shown that use sample covariance matrix, all pooled, impairs detection a sustained step shift in mean vector. example, that, probability signal actually decreases below...