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Large Plants (large + plant)
Selected AbstractsPRODUCT MARKET AND THE SIZE,WAGE DIFFERENTIAL*INTERNATIONAL ECONOMIC REVIEW, Issue 1 2002SHOUYONG SHI Using directed search to model the product market and the labor market, I show that large plants can pay higher wages to homogeneous workers and earn higher expected profit per worker than small plants, although plants are identical except size. A large plant charges a higher price for its product and compensates buyers with a higher service probability. To capture this size- related benefit, large plants try to become larger by recruiting at high wages. This size,wage differential survives labor market competition because a high wage is harder to get than a low wage. Moreover, the size,wage differential increases with the product demand when demand is initially low and falls when demand is already high. [source] Sex, age, and family differences in the chemical composition of owl monkey (Aotus nancymaae) subcaudal scent secretionsAMERICAN JOURNAL OF PRIMATOLOGY, Issue 1 2008Edith A. MacDonald Abstract Numerous behavioral studies have shown that animals use olfactory cues as inbreeding avoidance or kin avoidance mechanisms, implying that scent is unique to families. However, few studies have analyzed the chemical profile of a scent and ascertained the messages that are conveyed in scent secretions. Owl monkeys (Aotus nancymaae) are socially monogamous primates that utilize scent when interacting with foreign conspecifics. This suggests there is a difference in the chemical composition of scent marks. We chemically analyzed sub-caudal gland samples from three families of captive owl monkeys (Aotus nancymaae). Samples were analyzed by capillary GC-MS and relative retention time and fragment pattern was compared with known standards. Gland samples were high in large plant-based shikikate metabolites and fatty ketones; alcohols, acids, and acetates were virtually absent. Gender, age, and family could be reliably classified using discriminant analysis (92.9, 100, and 100%, respectively). Female scent profiles were greater in concentration of aromatic plant metabolites, possibly the result of a different diet or physiological differences in female metabolism as compared to male. Offspring of adult age still living in their natal group showed a less complex chemical profile than their parents. Finally, each family had its own unique and complex chemical profile. The presence of family scent may play a role in mediating social interactions. Am. J. Primatol. 70:12,18, 2007. © 2007 Wiley-Liss, Inc. [source] PRODUCT MARKET AND THE SIZE,WAGE DIFFERENTIAL*INTERNATIONAL ECONOMIC REVIEW, Issue 1 2002SHOUYONG SHI Using directed search to model the product market and the labor market, I show that large plants can pay higher wages to homogeneous workers and earn higher expected profit per worker than small plants, although plants are identical except size. A large plant charges a higher price for its product and compensates buyers with a higher service probability. To capture this size- related benefit, large plants try to become larger by recruiting at high wages. This size,wage differential survives labor market competition because a high wage is harder to get than a low wage. Moreover, the size,wage differential increases with the product demand when demand is initially low and falls when demand is already high. [source] Recall event timing: Measures of managerial performance in U.S. meat and poultry plantsAGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2005Ratapol Teratanavat This study investigates the performance of meat and poultry plant managers in discovering and responding effectively to food safety problems that lead to product recalls. Timing is used as a performance measure of managers' response to recalls of food, using survival distributions of times between production and recall, and recall case duration. The objectives are to understand how these time periods vary across plants and to determine factors explaining such variability. Survival distributions are estimated using the Kaplan-Meier and life table methods. Subgroups of the population are compared using plots of the estimated survival functions and statistically compared using log-rank and Wilcoxon tests. Managers at large plants, in multi-plant firms, and at plants with prior recall experience do not perform better. Cox regressions indicate that government agency sampling programs enhanced the speed of discovery, and that national distribution networks contributed to the risk that cases remained open for a longer period. [EconLit citations: D210, Q180.] © 2005 Wiley Periodicals, Inc. Agribusiness 21: 351,373, 2005. [source] When and Why do Plants Comply?LAW & POLICY, Issue 2 2005Paper Mills in the 1980s This paper uses census data for 116 pulp and paper mills over the period 1979,1990 to examine the determinants of compliance with air pollution regulations. Several plant characteristics are significant: large plants, old plants, and pulp mills comply less frequently, as do plants with water pollution or OSHA violations, but firm characteristics generally are not significant. Enforcement activity increases compliance, but in a heterogeneous way: pulp mills are less sensitive to inspections, while plants owned by larger firms are less sensitive to inspections and more sensitive to "other" enforcement actions, consistent with the authors' expectations and prior research results. [source] Nutrient versus pollination limitation in Platanthera bifolia and Dactylorhiza incarnata (Orchidaceae)OIKOS, Issue 2 2000Elisa Mattila Availability of resources and pollination services have been demonstrated to have impact on reproductive success in some orchid species, but to our knowledge no studies have examined the effects of nutrient application and pollination limitation in the same experiment. In this study, factors limiting reproductive success were studied with two terrestrial orchid species in Central Finland during 1996 and 1997. In a field experiment using a factorial design, plants of nectar-producing Platanthera bifolia and nectarless Dactylorhiza incarnata were treated with nutrient application and hand-pollination. Inflorescence size was considered as an indicator of attractiveness to pollinators as well as of the general condition of the plant. In 1996, fertilizer treatment increased relative capsule production in P. bifolia plants with small inflorescences, indicating poorer store of resources in the underground corm and dependence on nutrient availability during capsule maturation, which was not found in large plants. Hand-pollination and large inflorescence size in P. bifolia did not affect capsule initiation, but increased the proportion of mature capsules. P. bifolia may thus be regarded as both resource- and pollination-limited within a year. Pollination success was observed to be the only factor limiting reproduction of the nectarless D. incarnata within a year, because hand-pollination increased capsule production, and there were no significant effects of fertilizer treatment or inflorescence size in 1996. Capsule production in 1996 did not affect the probability of P. bifolia flowering in the following year, while high capsule production decreased the subsequent probability of flowering in D. incarnata. Species with different pollination strategies differed in the use of resources. The nectar-producing P. bifolia had a lower fruit/flower ratio than the nectarless D. incarnata, also after hand-pollination. [source] Herbivory and Abiotic Factors Affect Population Dynamics of Arabidopsis thaliana in a Sand Dune AreaPLANT BIOLOGY, Issue 5 2005A. Mosleh Arany Abstract: Population dynamics of the annual plant Arabidopsis thaliana (L.) Heynh. were studied in a natural habitat of this species on the coastal dunes of the Netherlands. The main objective was to elucidate factors controlling population dynamics and the relative importance of factors affecting final population density. Permanent plots were established and plants were mapped to obtain data on survival and reproductive performance of each individual, with special attention to herbivore damage. In experimental plots we studied how watering, addition of nutrients, artificial disturbance, and natural herbivores affected survival and growth. Mortality was low during autumn and early winter and high at the time of stem elongation, between February and April. A key factor analysis showed a high correlation between mortality from February to April and total mortality. The specialist weevils Ceutorhyncus atomus and C. contractus (Curculionidae) were identified as the major insect herbivores on A. thaliana, reducing seed production by more than 40 %. These herbivores acted in a plant size-dependent manner, attacking a greater fraction of the fruits on large plants. While mortality rates were not affected by density, fecundity decreased with density, although the effect was small. Adding water reduced mortality in rosette and flowering plant stages. Soil disturbance did not increase seed germination, but did have a significant positive effect on survival of rosette and flowering plants. Seed production of A. thaliana populations varied greatly between years, leading to population fluctuations, with a small role for density-dependent fecundity and plant size-dependent herbivory. [source] Carbon use efficiency depends on growth respiration, maintenance respiration, and relative growth rate.PLANT CELL & ENVIRONMENT, Issue 9 2003A case study with lettuce ABSTRACT Carbon use efficiency (CUE, the ratio between the amount of carbon incorporated into dry matter to the amount of carbon fixed in gross photosynthesis) is an important parameter in estimating growth rate from photosynthesis data or models. It previously has been found to be relatively constant among species and under different environmental conditions. Here it is shown that CUE can be expressed as a function of the relative growth rate (rGR) and the growth (gr) and maintenance respiration coefficients (mr): 1/CUE = 1 + gr + mr/rGR. Net daily carbon gain (Cdg), rGR, and CUE were estimated from whole-plant gas exchange measurements on lettuce (Lactuca sativa L.) ranging from 24 to 66 d old. Carbon use efficiency decreased from 0.6 to 0.2 with increasing dry mass, but there was no correlation between CUE and Cdg. The decrease in CUE with increasing dry mass was correlated with a simultaneous decrease in rGR. From the above equation, gr and mr were estimated to be 0.48 mol mol,1 and 0.039 g glucose g,1 dry matter d,1, respectively. Based on the gr estimate, the theoretical upper limit for CUE of these plants was 0.68. The importance of maintenance respiration in the carbon balance of the plants increased with increasing plant size. Maintenance accounted for 25% of total respiration in small plants and 90% in large plants. [source] Population dynamics of an endangered heathland shrub, Epacris stuartii (Epacridaceae): Recruitment, establishment and survivalAUSTRAL ECOLOGY, Issue 1 2002David A. Keith Abstract The only known population of the endangered shrub Epacris stuartii Stapf was studied from 1994 to 2001 using demographic census techniques. The effects of substrate, a fire and a storm on the emergence and survival of seedlings and the survival of established plants of different sizes were examined using failure-time analyses and logit-linear models. Ninety-five per cent of seedling emergence was delayed until the second post-fire spring, an unusual response among species with persistent soil seed banks. Mortality of seedlings was extreme compared with larger-seeded species, but diminished significantly with age. Seedling mortality varied significantly between substrates: 40% of seedlings persisted for more than 5 years in mineral soil, whereas less than 10% lived more than a year on rock and intermediate substrates. However, seedling numbers and local densities were lower on soils than other substrates. Background mortality of established plants was lower on soil and intermediate substrates (0.5% per year) than on rock (3% per year). Small plants may be more susceptible than large plants on rock, but not on soil. Both the fire and the storm resulted in elevated mortality of established plants. The population exhibited a variable response to fire, with plants on rock and intermediate substrates behaving as obligate seeders, whereas plants in soil resprouted. This appears to be the first report of microhabitat variation in fire response at sympatric scales. The effects of the storm were apparently independent of substrate and plant size. The essentially independent disturbance regimes comprising recurring fires and storms are likely to have a profound effect on the long-term population dynamics of E. stuartii. Over the 7-year census period, recruitment has failed to compensate for mortality, resulting in a 30% net decline in the population. The demographic census has proved to be crucial in the detection and diagnosis of this decline. [source] Climate, size and flowering history determine flowering pattern of an orchidBOTANICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 4 2006MARION PFEIFER The flowering pattern of plant species, including orchid species, may fluctuate irregularly. Several explanations are given in the literature to explain that pattern, including: costs associated with reproduction, herbivory effects, intrinsically triggered unpredictable variation of the system, and external conditions (i.e. weather). The influence of age is discussed, but is difficult to determine because relevant long-term field observations are generally absent in the literature. The influence of age, size, reproductive effort and climatic conditions on flowering variability of Himantoglossum hircinum are examined using data collected in a long-term project (1976,2001) in Germany. PCA and multiple regression analysis were used to analyse variability in flowering pattern over the years as a function of size and weather variability. We studied future size after flowering to quantify costs of reproduction. Flowering probability was strongly determined by plant size, while there was no significant influence of age class on flowering probability of the population. Costs associated with reproduction resulted in a decrease in plant size, causing reduced flowering probability of the plants in the following year. The weather explained about 50% of the yearly variation in the proportion of large plants and thus had an indirect, strong influence on the flowering percentage. We conclude that variability in flowering is caused mainly by the variability of weather conditions in the previous and current year, whereby reproductive effort causes further variability in flowering at the individual and, consequently, the population levels. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 151, 511,526. [source] | |||||||||||||||||||||||||