Distribution by Scientific Domains
Distribution within Business, Economics, Finance and Accounting

Terms modified by Productive

  • productive area
  • productive efficiency
  • productive firm
  • productive grassland
  • productive habitat
  • productive infection
  • productive lake
  • productive life
  • productive performance
  • productive potential
  • productive process
  • productive relationship
  • productive resource
  • productive role
  • productive site
  • productive system
  • productive use
  • productive value
  • productive way

  • Selected Abstracts

    The Role of Government Policy on Entrepreneurial Activity: Productive, Unproductive, or Destructive?

    Maria Minniti
    This paper serves as an introduction to the special issue of Entrepreneurship Theory and Practice on government policy and entrepreneurial activity. Entrepreneurship is an important engine of growth. Government policy, in turn, shapes the institutional environment in which entrepreneurial decisions are made. Thus, government policy is important for entrepreneurship. But what policies are more conducive to productive entrepreneurship? In spite of a significant amount of work on this and related topics, there is still much we do not know about this important relationship. After reviewing recent literature on entrepreneurship policy, this paper summarizes the contributions included in this volume and puts them in the context of the ongoing research debate. The goal of the special issue is to address important unanswered questions and trigger a constructive debate among diverging views. [source]

    Are Older Workers Less Productive?

    A Case Study of Aged Care Workers in Australia
    Employers are reluctant to employ older workers. Is this because they are less productive than equivalent younger workers? This paper uses data from a 2007 census of residential aged care homes in Australia to examine the productivity differentials of workers at different ages. We estimate production functions that take into account the age profile of the workforce in each aged care residential facility. We find that for the facilities having high care residents only, the productivity of nurses, whose work is more demanding of specialist knowledge, keeps increasing with age while the rate of increase declines after age 50. In contrast, the productivity of carers, whose work is more demanding of physical capacity, is highest in middle age. The facilities with low care residents only provide a much lower level of services because their residents are less frail and more independent. In this case, none of the coefficients regarding the impacts of age on productivity is statistically significant , suggesting that older workers are good substitutes for younger ones. [source]

    Development of a Highly Productive and Scalable Plasmid DNA Production Platform

    K. Listner
    With the applications of DNA vaccines extending from infectious diseases to cancer, achieving the most efficient, reproducible, robust, scalable, and economical production of clinical grade plasmid DNA is paramount to the medical and commercial success of this novel vaccination paradigm. A first generation production process based on the cultivation of Escherichia coli in a chemically defined medium, employing a fed-batch strategy, delivered reasonable volumetric productivities (500,750 mg/L) and proved to perform very well across a wide range of E. coli constructs upon scale-up at industrial scale. However, the presence of monosodium glutamate (MSG) in the formulation of the cultivation and feed solution was found to be a potential cause of process variability. The development of a second generation process, based on a defined cultivation medium and feed solution excluding MSG, was undertaken. Optimization studies, employing a plasmid coding for the HIV gag protein, resulted in cultivation conditions that supported volumetric plasmid titers in excess of 1.2 g/L, while achieving specific yields ranging from 25 to 32 ,g plasmid DNA/mg of dry cell weight. When used for the production of clinical supplies, this novel process demonstrated applicability to two other constructs upon scale-up in 2,000-L bioreactors. This second generation process proved to be scalable, robust, and highly productive. [source]

    "Cultivating Children as You Would Valuable Plants:" The Gardening Governmentality of Child Saving, Toronto, Canada, 1880s,1920s1

    Xiaobei Chen
    An analysis of gardening metaphors contributes to understanding mechanisms of bio-power on the site of child saving. This paper argues that the child saving movement attempted to install a mode of proper parental control that can be described as "the gardening governmentality", it was primarily positive/productive (yet without excluding repressive elements), individualized, intelligent, and localized. [source]

    Dialogic mediation in conflict resolution education

    Claudio Baraldi
    Conflict resolution education is an interesting field for both teachers and experts. This contribution tries to understand how conflict management can be productive in the interaction between adults and children. For this purpose, the results of field research are presented; they concern videotaped interaction in classrooms and formal groups of children coordinated by adults trying to support children's conflict management. The data show the adults' dialogic actions, which may promote children's conflict management, as well as the problems and limitations of these actions, highlighting coordination between adults' dialogic actions and children's agency in conflict resolution education. [source]

    Threatened Peripheral Populations in Context: Geographical Variation in Population Frequency and Size and Sexual Reproduction in a Clonal Woody Shrub

    especies en riesgo; límites de distribución; poblaciones periféricas; reproducción sexual; Vaccinium stamineum Abstract:,Geographically peripheral populations of widespread species are often the focus of conservation because they are locally rare within political jurisdictions. Yet the ecology and genetics of these populations are rarely evaluated in a broader geographic context. Most expectations concerning the ecology and evolution of peripheral populations derive from the abundant-center model, which predicts that peripheral populations should be less frequent, smaller, less dense, and have a lower reproductive rate than central populations. We tested these predictions and in doing so evaluated the conservation value of peripheral populations for the clonal shrub Vaccinium stamineum L. (Ericaceae, deerberry), which is listed as threatened in Canada. Based on 51 populations sampled from the center to the northern range limits over 2 years, population frequency and size declined toward the range limit, but ramet density increased. Sexual reproductive output varied widely among populations and between years, with many populations producing very few seeds, but did not decline toward range margins. In fact seed mass increased steadily toward range limit, and this was associated with faster germination and seedling growth, which may be adaptive in seasonal northern environments. Our results did not support the prediction that clonal reproduction is more prevalent in peripheral populations or that it contributed antagonistically to the wide variation in seed production. Peripheral populations of V. stamineum are as productive as central populations and may be locally adapted to northern environments. This emphasizes the importance of a broad geographical perspective for evaluating the ecology, evolution, and conservation of peripheral populations. Resumen:,Las poblaciones geográficamente periféricas de una especie de amplia distribución a menudo son el foco de conservación porque son raras localmente dentro de jurisdicciones políticas. Sin embargo, la ecología y genética de estas poblaciones son evaluadas poco frecuentemente en un contexto geográfico más amplio. La mayoría de las expectaciones relacionadas con la ecología y evolución de las poblaciones periféricas se derivan del modelo centro-abundante, que predice que las poblaciones periféricas son menos frecuentes, más pequeñas, menos densas y menor tasa reproductiva que poblaciones centrales. Probamos estas predicciones y al hacerlo evaluamos el valor de conservación de poblaciones periféricas de una especie de arbusto clonal (Vaccinium stamineum L., Ericaceae), que está enlistada como amenazada en Canadá. Con base en 51 poblaciones muestreadas del centro hacia los límites norteños de su distribución durante 2 años, la frecuencia y tamaño poblacional declinó hacia los límites de su distribución, pero la densidad de rametos aumentó. La reproducción sexual varió ampliamente entre las poblaciones y entre años, con muchas poblaciones produciendo muy pocas semillas, pero no declinó hacia los límites de su distribución. De hecho, la masa de semillas incrementó sostenidamente hacia los límites, y esto se asoció a una acelerada germinación y crecimiento de plántulas, lo cual puede ser adaptativo en ambientes norteños estacionales. Nuestros resultados no sustentaron la predicción de que la reproducción clonal es más prevaleciente en poblaciones periféricas o que contribuye antagónicamente a la amplia variación en la producción de semillas. Las poblaciones periféricas de V. stamineum son tan productivas como las poblaciones centrales y pueden estar adaptadas localmente a ambientes norteños. Esto enfatiza la importancia de una perspectiva geográfica amplia cuando se evalúa la ecología, evolución y conservación de poblaciones periféricas. [source]


    Research Summary: This study details a network analysis of the street gang landscape in Newark, New Jersey. Using individual gang members as the unit of analysis and multiple layers of associations as the linkages within the networks, the results suggest that the gangs in Newark are loosely organized with pockets of cohesion. In addition, there is variation with regard to individual connectedness within the gangs, and certain gang members emerge as "cut-points" or the only connection among gang members or groups of gang members. Policy Implications: The results lend further credence to the notion that problem analysis should precede gang interventions. In particular, the findings suggest that particular groups of gang members may be amenable to the collective accountability tactic, whereas others may become more cohesive as a consequence. Indeed, an intervention focused on individuals may be more productive in Newark. The cut-points within gangs are particularly worthy of attention, both for their capacity to act as communication agents for a deterrence message and for their potential vulnerability to the pulling levers strategy. [source]

    Teaching Treaties as (Un)Usual Narratives: Disrupting the Curricular Commonsense

    CURRICULUM INQUIRY, Issue 5 2008
    This article examines the importance of treaty education for students living in a province entirely ceded through treaty. Specifically, we ask and attempt to answer the questions "Why teach treaties?" and "What is the effect of teaching treaties?" We build on research that explores teachers' use of a treaty resource kit, commissioned by the Office of the Treaty Commissioner in Saskatchewan. Working with six classrooms representing a mix of rural, urban and First Nations settings, the research attempts to make sense of what students understand, know and feel about treaties, about First Nations peoples and about the relationships between First Nations and non,First Nations peoples in Saskatchewan. It is revealing that initially students are unable to make sense of their province through the lens of treaty given the commonsense story of settlement they learn through mandated curricula. We offer a critique of the curricular approach in Saskatchewan which separates social studies, history and native studies into discrete courses. Drawing on critical race theory, particularly Joyce King's notion of "dysconscious" racism, we deconstruct curriculum and its role in maintaining dominance and privilege. We use the term (un)usual narrative to describe the potential of treaty education to disrupt the commonsense. (Un)usual narratives operate as both productive and interrogative, helping students to see "new" stories, and make "new" sense of their province through the lens of treaty. [source]

    Service Businesses and Productivity,

    DECISION SCIENCES, Issue 3 2004
    Roger W. Schmenner
    ABSTRACT The records of superior performance of selected service firms over many years suggest that they may be more productive than others. This article uses the Theory of Swift, Even Flow to explain why that might be true. In the process, this article improves Schmenner's 1986 service process matrix. The redefinition of the axes of this matrix and of the resulting diagonal leads to enhanced understanding of productivity for service operations and helps to explain how some leading service companies have been able to sustain their competitive positions for decades. [source]

    Rubber Erasures, Rubber Producing Rights: Making Racialized Territories in West Kalimantan, Indonesia

    Nancy Lee Peluso
    ABSTRACT This article makes connections between often-disparate literatures on property, violence and identity, using the politics of rubber growing in West Kalimantan, Indonesia, as an example. It shows how rubber production gave rise to territorialities associated with and productive of ethnic identities, depending on both the political economies and cultural politics at play in different moments. What it meant to be Chinese and Dayak in colonial and post-colonial Indonesia, as well as how categories of subjects and citizens were configured in the two respective periods, differentially affected both the formal property rights and the means of access to rubber and land in different parts of West Kalimantan. However, incremental changes in shifting rubber production practices were not the only means of producing territory and ethnicity. The author argues that violence ultimately played a more significant role in erasing prior identity-based claims and establishing the controls of new actors over trees and land and their claims to legitimate access or ,rightfulness'. Changing rubber production practices and reconfigurations of racialized territories and identity-based property rights are all implicated in hiding the violence. [source]

    Nipple preference and contests in suckling kittens of the domestic cat are unrelated to presumed nipple quality

    Robyn Hudson
    Abstract We studied the development of suckling behavior and weight gain in 11 litters (52 kittens) of free-ranging domestic cats until postnatal day 28 just before the start of weaning. In six of these litters, we also recorded milk intake and contests for access to nipples. Already within 12 hr of birth kittens showed a preference for posterior nipples, and by postnatal day 3 each had developed a preference for particular nipples. In fact, 86% of kittens used one particular nipple most often, and even when the mother changed the side she lay on to nurse. Contests for access to nipples occurred throughout the study period at an average rate of one to two contests per kitten per hour of nursing. Contrary to suggestions in the literature that kittens compete for more productive nipples, we found no relation between kittens' use of particular nipples and their weight gain, milk intake, or involvement in contests during suckling. We suggest that kittens' preference for posterior nipples as well as their establishment of an individual "teat order" might function to optimize the number of nipples remaining productive across lactation, and to reduce energetically costly scrambles and potentially injurious contests among littermates. © 2009 Wiley Periodicals, Inc. Dev. Psychobiol 51: 322,332, 2009. [source]

    Characterizing the ADHD phenotype for genetic studies

    Jim Stevenson
    The genetic study of ADHD has made considerable progress. Further developments in the field will be reliant in part on identifying the most appropriate phenotypes for genetic analysis. The use of both categorical and dimensional measures of symptoms related to ADHD has been productive. The use of multiple reporters is a valuable feature of the characterization of psychopathology in children. It is argued that the use of aggregated measures to characterize the ADHD phenotype, particularly to establish its pervasiveness, is desirable. The recognition of the multiple comorbidities of ADHD can help to isolate more specific genetic influences. In relation to both reading disability and conduct disorder there is evidence that genes may be involved in the comorbid condition that are different from pure ADHD. To date, progress with the investigation of endophenotypes for ADHD has been disappointing. It is suggested that extending such studies beyond cognitive underpinnings to include physiological and metabolic markers might facilitate progress. [source]

    Between court and counts: Carolingian Catalonia and the aprisio grant, 778,897

    Cullen J. Chandler
    In the late eighth century, Charlemagne issued a new kind of land grant in Septimania and the Spanish March to refugees fleeing Muslim Spain. This grant, the aprisio, was made from fiscal land in deserted areas and included special rights and immunities. Previous scholars have interpreted the aprisio in economic and military terms as a mechanism to entice settlers to the region in order to make the land productive and to provide warriors to defend the Frankish frontier. This article suggests that political concerns also may have played an important role, arguing that the aprisio grant was an attempt by Carolingian kings to limit the power exercised by very powerful marcher counts. [source]

    Effects of summer grazing by reindeer on composition of vegetation, productivity and nitrogen cycling

    ECOGRAPHY, Issue 1 2001
    Johan Olofsson
    In this study, we investigated the effect of reindeer grazing on tundra heath vegetation in northern Norway. Fences, erected 30 yr ago, allowed us to compare winter grazed, lightly summer grazed and heavily summer grazed vegetation at four different sites. At two sites, graminoids dominated the heavily grazed zone completely, while ericoid dwarf shrubs had almost disappeared. In the other two areas, the increase of graminoids was almost significant. At one of the sites where graminoids dominated the heavily grazed area, we also measured plant biomass, primary production and nitrogen cycling. In this site, heavy grazing increased primary production and rate of nitrogen cycling, while moderate grazing decreased primary production. These results were inconsistent with the view that the highest productivity is found at intermediate grazing pressure. These results rather support the hypothesis that intensive grazing can promote a transition of moss-rich heath tundra into productive, graminoid-dominated steppe-like tundra vegetation. Moreover the results suggests that intermittent intensive reindeer grazing can enhance productivity of summer ranges. [source]

    The Impact of the Demand for Clinical Productivity on Student Teaching in Academic Emergency Departments

    Todd J. Berger MD
    Objective: Because many emergency medicine (EM) attending physicians believe the time demands of clinical productivity limit their ability to effectively teach medical students in the emergency department (ED), the purpose of this study was to determine if there is an inverse relationship between clinical productivity and teaching evaluations. Methods: The authors conducted a prospective, observational, double-blind study. They asked senior medical students enrolled in their EM clerkship to evaluate each EM attending physician who precepted them at three academic EDs. After each shift, students anonymously evaluated 10 characteristics of clinical teaching by their supervising attending physician. Each attending physician's clinical productivity was measured by calculating their total relative value units per hour (RVUs/hr) during the nine-month study interval. The authors compared the total RVUs/hr for each attending physician to the medians of their teaching evaluation scores at each ED using a Spearman rank correlation test. Results: Seventy of 92 students returned surveys, evaluating 580 shifts taught by 53 EM attending physicians. Each attending physician received an average of 11 evaluations (median score, 5 of 6) and generated a mean of 5.68 RVUs/hr during the study period. The correlation between evaluation median scores and RVUs/hr was ,0.08 (p = 0.44). Conclusions: The authors found no statistically significant relationship between clinical productivity and teaching evaluations. While many EM attending physicians perceive patient care responsibilities to be too time consuming to allow them to be good teachers, the authors found that a subset of our more productive attending physicians are also highly rated teachers. Determining what characteristics distinguish faculty who are both clinically productive and highly rated teachers should help drive objectives for faculty development programs. [source]

    The governance and performance of universities: evidence from Europe and the US

    ECONOMIC POLICY, Issue 61 2010
    Philippe Aghion
    Summary We test the hypothesis that universities are more productive when they are both more autonomous and face more competition. Using survey data, we construct indices of university autonomy and competition for both Europe and the United States. We show that there are strong positive correlations between these indices and multiple measures of university output. To obtain causal evidence, we investigate exogenous shocks to US universities' expenditures over three decades. These shocks arise through the political appointment process, which we use to generate instrumental variables. We find that an exogenous increase in a university's expenditure generates more output, measured by either patents or publications, if the university is more autonomous and faces more competition. Exploiting variation over time in the ,stakes' of competitions for US federal research grants, we also find that universities generate more output for a given expenditure when research competitions are high stakes. We draw lessons, arguing that European universities could benefit from a combination of greater autonomy and greater accountability. Greater accountability might come through increased reliance on competitive grants, enhanced competition for students and faculty (promoted by reforms that increase mobility), and yardstick competitions (which often take the form of assessment exercises). --- Philippe Aghion, Mathias Dewatripont, Caroline Hoxby, Andreu Mas-Colell and André Sapir [source]

    Social Contacts and Occupational Choice

    ECONOMICA, Issue 305 2010
    Social contacts help to find jobs, but not necessarily in the occupations where workers are most productive. Hence social contacts can generate mismatch between workers' occupational choices and their productive advantage. Accordingly, social networks can lead to low labour force quality, low returns to firms' investment and depressed aggregate productivity. We analyse surveys from both the US and Europe including information on job finding through contacts. Consistent with our predictions, contacts reduce unemployment duration by 1,3 months on average, but they are associated with wage discounts of at least 2.5%. We also find some evidence of negative externalities on aggregate productivity. [source]

    Strategic Use of Corporate Venturing

    Jeffrey G. Covin
    Corporate venturing (CV) is said to be most productive as a path to superior corporate performance when practiced in a strategic manner. Unfortunately, considerable ambiguity exists concerning what it means in an organizational practice sense to strategically pursue CV. The result is a failure of many companies to fully leverage CV for strategic purposes. Based on a review of the CV literature and findings from a field study of 15 Swedish, U.K., and U.S. corporations, this article describes several models that depict the ways in which CV and business strategy coexist as organizational phenomena. Empirically derived propositions are offered to suggest how some companies are strategically engaged in their CV efforts. [source]


    EVOLUTION, Issue 5 2004
    Ken R. Helms
    Abstract A recent study by Fournier et al. (2003) provides important new information on sex allocation in the ant Pheidole pallidula, and proposes a new scenario for sex-ratio evolution in P. pallidula and similar species. However, Helms proposed to the authors that two important conclusions of the study were questionable because of potential problems with the analyses. Here we provide new data and a reanalysis that strengthens the conclusion that colony sex ratio is associated with breeding system (i.e., polygyny or monogyny). However, the proposal that colonies shift from monogyny to polygyny when they become larger and more productive is weakened because there is substantial overlap in productivity between monogynous and polygynous colonies. [source]

    Culture-based fisheries in non-perennial reservoirs in Sri Lanka: production and relative performance of stocked species

    Abstract, In Sri Lanka, there is a great potential for the development of culture-based fisheries because of the availability of around 12 000 non-perennial reservoirs in the dry zone (<187 cm annual rainfall) of the island. These reservoirs fill during the north-east monsoonal period in October to December and almost completely dry up during August to October. As these non-perennial reservoirs are highly productive, hatchery-reared fish fingerlings can be stocked to develop culture-based fisheries during the water retention period of 7,9 months. The present study was conducted in 32 non-perennial reservoirs in five administrative districts in Sri Lanka. These reservoirs were stocked with fingerlings of Indian (catla Catla catla Hamilton and rohu Labeo rohita Hamilton) and Chinese (bighead carp Aristichthys nobilis Richardson) major carps, common carp Cyprinus carpio L., genetically improved farmed tilapia (GIFT) strain of Nile tilapia, Oreochromis niloticus (L.) and post-larvae of giant freshwater prawn, Macrobrachium rosenbergii De Man, at three different species combinations and overall stocking densities (SD) ranging from 218 to 3902 fingerlings ha,1, during the 2002,2003 culture cycle. Of the 32 reservoirs stocked, reliable data on harvest were obtained from 25 reservoirs. Fish yield ranged from 53 to 1801 kg ha,1 and the yields of non-perennial reservoirs in southern region were significantly (P < 0.05) higher than those in the northern region. Naturally-recruited snakehead species contributed the catches in northern reservoirs. Fish yield was curvilinearly related to reservoir area (P < 0.05), and a negative second order relationship was evident between SD and yield (P < 0.05). Chlorophyll- a and fish yield exhibited a positive second order relationship (P < 0.01). Bighead carp yield impacted positively on the total yield (P < 0.05), whereas snakehead yield impact was negative. Bighead carp, common carp and rohu appear suitable for poly-culture in non-perennial reservoirs. GIFT strain O. niloticus had the lowest specific growth rate among stocked species and freshwater prawn had a low return. [source]

    Differing body size between the autumn and the winter,spring cohorts of neon flying squid (Ommastrephes bartramii) related to the oceanographic regime in the North Pacific: a hypothesis

    Taro Ichii
    Abstract The neon flying squid (Ommastrephes bartramii), which is the target of an important North Pacific fishery, is comprised of an autumn and winter,spring cohort. During summer, there is a clear separation of mantle length (ML) between the autumn (ML range: 38,46 cm) and the winter,spring cohorts (ML range: 16,28 cm) despite their apparently contiguous hatching periods. We examined oceanic conditions associated with spawning/nursery and northward migration habitats of the two different-sized cohorts. The seasonal meridional movement of the sea surface temperature (SST) range at which spawning is thought to occur (21,25°C) indicates that the spawning ground occurs farther north during autumn (28,34°N) than winter,spring (20,28°N). The autumn spawning ground coincides with the Subtropical Frontal Zone (STFZ), characterized by enhanced productivity in winter because of its close proximity to the Transition Zone Chlorophyll Front (TZCF), which move south to the STFZ from the Subarctic Boundary. Hence this area is thought to become a food-rich nursery ground in winter. The winter,spring spawning ground, on the other hand, coincides with the Subtropical Domain, which is less productive throughout the year. Furthermore, as the TZCF and SST front migrate northward in spring and summer, the autumn cohort has the advantage of being in the SST front and productive area north of the chlorophyll front, whereas the winter,spring cohort remains to the south in a less productive area. Thus, the autumn cohort can utilize a food-rich habitat from winter through summer, which, we hypothesize, causes its members to grow larger than those in the winter,spring cohort in summer. [source]

    Advanced Heritage Learners of Spanish: A Sociolinguistic Profile for Pedagogical Purposes

    Irma Alarcón
    Abstract: This article reports on an extensive survey administered to advanced heritage language (HL) learners to examine their language behaviors, attitudes, and backgrounds. To date, there have been no detailed categorizations of advanced HL learners to guide classroom instruction and curriculum design. Thus the present study is a first attempt to fill this gap by providing a sociolinguistic profile of these speakers, including their identifying characteristics, linguistic needs, and similarities and differences with lower-proficiency speakers. Survey responses indicate that advanced HL learners possess both productive and receptive skills in the HL, always use Spanish at home, are fluent speakers of a standard variety, already have basic academic skills in Spanish, and are therefore primarily interested in perfecting their academic writing skills. [source]

    Effects of Word and Fragment Writing During L2 Vocabulary Learning

    Joe Barcroft
    This study examined how writing (copying) target words and word fragments affects intentional second language (L2) vocabulary learning. English-speaking first-semester learners ofSpanish attempted to learn 24 Spanish nouns via word-picture repetition in three conditions: (1) word writing, (2) fragment writing, and (3) no writing. After the learning phase, the participants completed productive (picture-to-L2) and recpectively oriented (L2-to-first language) posttests. Vocabulary learning scores in the no-writing condition were higher than in the other two conditions and higher in the word-writing condition than in the fragment-writing condition. These fmdings provide new evidence on how forced Output without access to meaning can detract from early word learning by exhausting processing resources needed to encode new word forms. The pedagogical implications of the study call for language instructors to rethink the practice of encouraging students to write down a word to remember it. [source]

    Effects of sequential depositional basins on lake response to urban and agricultural pollution: a palaeoecological analysis of the Qu'Appelle Valley, Saskatchewan, Canada

    FRESHWATER BIOLOGY, Issue 3 2000
    Aruna S. Dixit
    1. Palaeolimnological analyses of fossil diatoms and pigments were conducted in four lakes of the Qu'Appelle Valley, Saskatchewan, Canada, to quantify the effect of upstream depositional basins on lake response to urban and agricultural human activities. Pasqua, Echo, Mission and Katepwa lakes exhibit similar modern limnological characteristics, lie sequentially downstream from urban point sources of growth-limiting nitrogen (N), yet drain similarly large areas of farmland (38,40 × 103 km2). 2. Analyses indicated that all lakes were naturally productive, contained eutrophic diatoms (i.e. Stephanodiscus niagarae, S. hantzchii, S. parvus and Aulacoseira granulata), and supported blooms of colonial (as myxoxanthophyll) and potentially toxic N-fixing cyanobacteria (aphanizophyll), even prior to the onset of European settlement (ca. 1890) and urban development (ca. 1930). 3. The onset of agricultural practices ca. 1890 had only modest effects on algal communities in the Qu'Appelle lakes, with subtle increases in eutrophic diatom species (Pasqua, Mission and Katepwa lakes) and 25,50% increases in pigment-inferred algal abundance (Echo, Mission and Katepwa lakes). 4. Despite naturally high production, total algal abundance (,-carotene) in upstream Pasqua Lake increased by more than 350% after intense urbanization beginning ca. 1930, while eutrophic diatoms became more common and cyanobacteria populations increased ten-fold. Principal components analysis (PCA) explained 64% of diatom variance, and identified three eras corresponding to baseline, pre-agricultural communities (1776,1890), an era of high production (ca. 1925,1960) and recent variable community composition following tertiary treatment of urban sewage (ca. 1977,1990). 5. Analyses of three downstream lakes demonstrated that urban impacts following 1930 remained evident in fossil profiles of ,-carotene and myxoxanthophyll, but that large blooms of N-fixing cyanobacteria were restricted to the past 25 years at downstream Mission and Katepwa lakes. Similarly, PCA showed that fossil diatom assemblages exhibited little directional variation until the 1970s. 6. Together, these analyses support the hypothesis that upstream lakes were effective at reducing the impacts of point-source urban nutrients on downstream lakes. In contrast, diffuse agricultural activities had only limited impacts on water quality and these were less well ameliorated by upstream basins. [source]

    Ecotype adaptation and acclimation of leaf traits to rainfall in 29 species of 16-year-old Eucalyptus at two common gardens

    FUNCTIONAL ECOLOGY, Issue 6 2006
    C. R. WARREN
    Summary 1Relationships of leaf traits with rainfall at the place of origin of seed (RPO) are a function of acclimation and adaptation. To disentangle these effects we studied 29 species of 16-year-old Eucalyptus at a productive and an unproductive common garden (mean annual increments of above-ground stem volume = 21 ± 11 and 8 ± 5 m3 ha,1 years,1, respectively). We tested three hypotheses: (i) leaf traits vary between sites, but relationships among them do not; (ii) relationships of leaf traits with RPO do not vary between sites; and (iii) ecotypes originating from low-rainfall areas allocate a small fraction of nitrogen to thylakoid proteins and Rubisco, and have small SLA, small and narrow leaves, and large water-use efficiency (WUE). 2Eleven leaf traits (leaf area, leaf thickness, leaf width/length, specific leaf area, fresh weight/dry weight, N, chlorophyll a/b, carotenoids/chlorophyll, thylakoid N%, Rubisco N%, WUE derived from 13C content) were measured in 1-year-old sun leaves. 3Site had a large effect on not only the absolute values of leaf traits, but also relationships between pairs of traits. There were 20 significant correlations between pairs of traits. Three of the correlations had different slopes between sites, while a further nine had different intercepts. Hence the majority of significant correlations were not independent of site. 4Leaf area and leaf width/length were the only traits related to RPO. There was no evidence that N allocation to Rubisco or thylakoid proteins was related to RPO, or that WUE was greater in ecotypes from dry areas. 5For Eucalyptus, and perhaps other genera, physiological leaf traits may play a minor role in adaptation to water availability. There is large phenotypic plasticity in many leaf traits affecting not only the absolute values of traits, but also relationships among them. [source]

    Prostitution as a Male Object of Epistemological Pain

    Hugo Letiche
    It is not, in the first place, prostitutes' physical and psychological pain that is examined in this article, but the pain encountered in trying to come to terms with the studying of prostitution. Prostitution upsets consciousness' efforts and confuses its epistemes of representation. It reveals issues of (male) avoidance and over-rationalization that apply just as well to how business and organization are (not) studied, as to prostitution. Following Artaud, we examine how, because prostitution is both consciousness (idea, theory, representation) and body (sex, body, the physiology of the brain), it poses the problem of doubling. How can one apprehend both: (i) that one is the physical hyle (materiality) of thought and also (ii) remain aware of the contents of consciousness? Artaud claimed that only in ,cruelty' and the ,scream' could the mind and body be grasped at once. By contrast, Derrida proposes via the subjectile to glide over the space between consciousness and body, trying to acknowledge but not be stymied by the double. Finally, we turn to Irigaray who has accepted doubling and has made it epistemologically productive. [source]

    Conformational switching of Escherichia coli RNA polymerase-promoter binary complex is facilitated by elongation factor GreA and GreB

    GENES TO CELLS, Issue 5 2001
    Ranjan Sen
    Background The initiation arrest at a modified ,PR promoter is caused by irreversible divergence of the reaction pathway into productive and arrested branches. Escherichia coli GreA and GreB induce cleavage of the nascent transcript and relieve arrest in elongation. They also reduce abortive synthesis at several promoters and relieve initiation arrest. Their mechanism of action during initiation, and its relationship to the branched initiation pathway are unknown. Results The Gre factors mitigated initiation arrest only when they were added to the binary complex of the holoenzyme bound to the ,PR promoter, prior to RNA synthesis. They exerted little effect when they were added to ternary initiation complexes. They accelerated the exchange of the binary complex with its free components by 6,9-fold. When they are present, a high concentration of the initiating nucleotide increased yield of the full-length transcript, whereas a low concentration did not. Conclusions All the results presented above can be explained by a model where the productive and arrested pathways diverge at the binary complex stage. The Gre factors relieve the initiation arrest by introducing reversibility between subspecies of the binary complex that are precursors of the two pathways. RNA cleavage is unlikely to cause relief of initiation arrest. [source]

    An Ordovician age for the Muggort's Bay Lower Palaeozoic inlier, County Waterford, Ireland,the southernmost exposure of the Irish Caledonides

    GEOLOGICAL JOURNAL, Issue 5 2005
    P. M. Brück
    Abstract The most southerly exposed Lower Palaeozoic strata in Ireland occur on the southwest coast of County Waterford along a 2.5,km long coastal section at Muggort's Bay where they are surrounded by Devonian rocks. Five formations can be distinguished which, in ascending order, are: the Ballycurreen, Carrickbrean, Rathnameenagh, Moanbrack and Killinoorin formations. The total thickness of the succession is over 1800,m. No macrofossils are present, but the lithologies are largely fine-grained turbidites and subordinate volcanic rocks which closely resemble the Ribband Group seen elsewhere in southeast Ireland and have previously therefore been classified with it. Palynological analysis was undertaken on 25 samples collected from Muggort's Bay, of which eight were productive. Diagnostic microfossils, comprising acritarchs, chitinozoans and scolecodonts, indicate an Early to Middle Ordovician age for both the Rathnameenagh and the Moanbrack formations. These ages confirm that the strata are part of the Ribband Group which elsewhere has been biostratigraphically dated as ranging from Mid-Cambrian to Mid-Ordovician. Reworked mid-Middle Cambrian acritarchs occur in the Moanbrack Formation and reworked late Middle to early Late Cambrian acritarchs in the Rathnameenagh Formation. Despite generally poor preservation of the organic matter, some 20 acritarch species have been distinguished. Among these, three species belong to the herein revised genus Retisphaeridium for which an emended diagnosis is proposed together with two new combinations, Retisphaeridium capsulatum (Jankauskas, 1976) Vanguestaine nov. comb. and Retisphaeridium pusillum (Moczydlowska, 1998) Vanguestaine nov. comb. Copyright © 2005 John Wiley & Sons, Ltd. [source]

    Climatic signals in growth and its relation to ENSO events of two Prosopis species following a latitudinal gradient in South America

    Abstract Semiarid environments throughout the world have lost a major part of their woody vegetation and biodiversity due to the effects of wood cutting, cattle grazing and subsistence agriculture. The resulting state is typically used for cattle production, but the productivity of these systems is often very low, and erosion of the unprotected soil is a common problem. Such dry-land degradation is of great international concern, not only because the resulting state is hardly productive but also because it paves the way to desertification. The natural distribution of the genus Prosopis includes arid and semiarid zones of the Americas, Africa and Asia, but the majority of the Prosopis species are, however, native to the Americas. In order to assess a likely gradient in the response of tree species to precipitation, temperature and their connection to El Niño southern oscillation (ENSO) events, two Prosopis species were chosen along a latitudinal gradient in Latin America, from northern Peru to central Chile: Prosopis pallida from a semi-arid land in northern and southern Peru and P. chilensis from a semiarid land in central Chile. Growth rings of each species were crossdated at each sampling site using classical dendrochronological techniques. Chronologies were related with instrumental climatic records in each site, as well as with SOI and N34 series. Cross-correlation, spectral and wavelet analysis techniques were used to assess the relation of growth with precipitation and temperature. Despite the long distance among sites, the two Prosopis species presented similar responses. Thus, the two species' growth is positively correlated to precipitation, while with temperature it is not. In northern Peru, precipitation and growth of P. pallida present a similar cyclic pattern, with a period of around 3 years. On the other hand, P. pallida in southern Peru, and P. chilensis also present this cyclic pattern, but also another one with lower frequency, coinciding with the pattern of precipitation. Both cycles are within the range of the ENSO band. [source]

    Innovation and Regional Growth in the Enlarged Europe: The Role of Local Innovative Capabilities, Peripherality, and Education

    GROWTH AND CHANGE, Issue 4 2005
    ABSTRACT In this paper, a formal model for the relationship between innovation and growth in European Union regions is developed drawing upon the theoretical contribution of the systems of innovation approach. The model combines the analytical approach of the regional growth models with the insights of the systemic approach. The cross-sectional analysis, covering all the Enlarged Europe (EU-25) regions (for which data are available), shows that regional innovative activities (for which a specific measure is developed) play a significant role in determining differential regional growth patterns. Furthermore, the model sheds light on how geographical accessibility and human capital accumulation, by shaping the regional system of innovation, interact (in a statistically significant way) with local innovative activities, thus allowing them to be more (or less) effectively translated into economic growth. The paper shows that an increase in innovative effort is not necessarily likely to produce the same effect in all EU-25 regions. Indeed, the empirical analysis suggests that in order to allow innovative efforts in peripheral regions to be as productive as in core areas, they need to be complemented by huge investments in human capital. [source]