Methodological issues in testing the marginal productivity theory

Previous tests of the marginal productivity theory have been criticized on several grounds reviewed by the authors. One important deficiency has been the small number of factor inputs entered in the production functions. In 1978 Gottschalk suggested a method to estimate production functions with many inputs by assuming that the production process can be split into subprocesses. This reduces the probability of multicollinearity. The authors show that the method depends on an additional assumption. Tinbergen has developed a method for avoiding this assumption. Its application to American cross-section (state) data did not alter the estimated coefficients greatly

Feeding regimens in finishing phase of beef cattle on corporal development and meat quality.

Despite to be a traditional activity in southern Brazil, beef cattle production based exclusively in natural grasslands normally presents low animal productivity, reflecting a misunderstanding of basic management practices like control of forage allowance and or lack of utilization of others possibilities of foraging

Polycyclic aromatic hydrocarbons in the dwarf galaxy IC 10

Infrared observations from the Spitzer Space Telescope archive are used to study the dust component of the interstellar medium in the IC~10 irregular galaxy. Dust distribution in the galaxy is compared to the distributions of H$\alpha$ and [SII] emission, neutral hydrogen and CO clouds, and ionizing radiation sources. The distribution of polycyclic aromatic hydrocarbons (PAH) in the galaxy is shown to be highly non-uniform with the mass fraction of these particles in the total dust mass reaching 4%. PAHs tend to avoid bright HII regions and correlate well with atomic and molecular gas. This pattern suggests that PAHs form in the dense interstellar gas. We propose that the significant decrease of the PAH abundance at low metallicity is observed not only globally (at the level of entire galaxies), but also locally (at least, at the level of individual HII regions). We compare the distribution of the PAH mass fraction to the distribution of high-velocity features, that we have detected earlier in wings of H$\alpha$ and SII lines, over the entire available galaxy area. No conclusive evidence for shock destruction of PAHs in the IC~10 galaxy could be found.Comment: Accepted for publication in Astronomy Report

A Region of Violent Star Formation in the Irr Galaxy IC 10: Structure and Kinematics of Ionized and Neutral Gas

We have used observations of the galaxy IC 10 at the 6-m telescope of the Special Astrophysical Observatory with the SCORPIO focal reducer in the Fabry-Perot interferometer mode and with the MPFS spectrograph to study the structure and kinematics of ionized gas in the central region of current intense star formation. Archive VLA 21-cm observations are used to analyze the structure and kinematics of neutral gas in this region. High-velocity wings of the H-alpha and [SII] emission lines were revealed in the inner cavity of the nebula HL 111 and in other parts of the complex of violent star formation. We have discovered local expanding neutral-gas shells around the nebulae HL 111 and HL 106.Comment: 22 pages, 10 figures; accepted in Astronomy Report

Impact of age norms and stereotypes on managers' hiring decisions of retirees

Purpose -Our study investigates the role of managers in the re-employment of early retirees and asks what the effect is of managers’ age norms and stereotypes on managers’ employment decisions. Design/methodology/approach- A combination of a factorial study and a survey was conducted. First, information on the age norms and stereotypes was collected. Secondly, profiles of hypothetical retired job applicants were presented to the employers, who were asked to make a specific hiring decision. The information collected during both studies was combined in the analysis and multilevel models were estimated. Findings -The results indicate that higher age norms result in a higher propensity to hire an early retiree. Stereotypes, by contrast, do not influence managers’ decisions. Early retirees’ chances for re-employment are also related to their own circumstances (physical appearance and relevant experience) and organisational forces, as they are hired when organisations face labour force shortages. Research limitation / implications – with the use of vignettes study we deal with hypothetical hiring situation. Originality value- Although the effect of age norms and age stereotypes has been often suggested, not much empirical evidence was presented to support this notion. Our study estimates the effect of age norms and stereotypes on hiring decision. key words: bridge employment; early retirees; age norms; age stereotypes; multilevel models.

Dialectics and difference: against Harvey's dialectical post-Marxism

David Harvey`s recent book, Justice, nature and the geography of difference (JNGD), engages with a central philosophical debate that continues to dominate human geography: the tension between the radical Marxist project of recent decades and the apparently disempowering relativism and `play of difference' of postmodern thought. In this book, Harvey continues to argue for a revised `post-Marxist' approach in human geography which remains based on Hegelian-Marxian principles of dialectical thought. This article develops a critique of that stance, drawing on the work of Jacques Derrida, Gilles Deleuze and Felix Guattari. I argue that dialectical thinking, as well as Harvey's version of `post-Marxism', has been undermined by the wide-ranging `post-' critique. I suggest that Harvey has failed to appreciate the full force of this critique and the implications it has for `post-Marxist' ontology and epistemology. I argue that `post-Marxism', along with much contemporary human geography, is constrained by an inflexible ontology which excessively prioritizes space in the theory produced, and which implements inflexible concepts. Instead, using the insights of several `post-' writers, I contend there is a need to develop an ontology of `context' leading to the production of `contextual theories'. Such theories utilize flexible concepts in a multilayered understanding of ontology and epistemology. I compare how an approach which produces a `contextual theory' might lead to more politically empowering theory than `post-Marxism' with reference to one of Harvey's case studies in JNGD

Lives on track? Long-term earnings returns to selective school placement in England and Denmark

We explore the influence of between-school ability placement at lower secondary education on earnings across the life course in England and Denmark. We go beyond the mid-career snapshot provided by previous studies by exploiting the availability of four decades worth of earnings data for individuals born in the mid-1950s. Members of this cohort who were judged to be among the most academically able attended grammar schools in England (19 percent) and advanced secondary schools (Realskole) in Denmark (51 percent) prior to the start of comprehensivisation. This key difference makes England and Denmark interesting cases for comparison, not least since pro-selection policies have re-emerged in England based on the claim that grammar schools lead to better educational and labour market outcomes. Our analysis of the influence of selective school placement on earnings finds little support for this contention. We find that those from socioeconomically disadvantaged backgrounds were strikingly under-represented in schools ear-marked for higher ability pupils in both countries, even after taking into account social class differences in measured ability. Our analysis for England finds only modest earnings returns to attending a grammar school, totalling just £39,000 across the life course, while in Denmark the lifetime earnings returns to attending Realskole are somewhat larger (£194,000). Because those from advantaged backgrounds were substantially over-represented at grammar schools and Realskoles, these returns accrue disproportionately to pupils from more advantaged backgrounds. Lower secondary school placement in Denmark accounts for forty percent of the intergenerational reproduction of socioeconomic advantage and disadvantage, more than half of which is due to selection into school types based on socioeconomic background rather than measured ability. Our findings question the wisdom of expanding grammar schools when they appear to do little to improve individuals’ earnings or increase social mobility