A curvilinear effect of height on reproductive success in human males

Human male height is associated with mate choice and intra-sexual competition, and therefore potentially with reproductive success. A literature review (n = 18) on the relationship between male height and reproductive success revealed a variety of relationships ranging from negative to curvilinear to positive. Some of the variation in results may stem from methodological issues, such as low power, including men in the sample who have not yet ended their reproductive career, or not controlling for important potential confounders (e.g. education and income). We investigated the associations between height, education, income and the number of surviving children in a large longitudinal sample of men (n = 3,578; Wisconsin Longitudinal Study), who likely had ended their reproductive careers (e.g. > 64 years). There was a curvilinear association between height and number of children, with men of average height attaining the highest reproductive success. This curvilinear relationship remained after controlling for education and income, which were associated with both reproductive success and height. Average height men also married at a younger age than shorter and taller men, and the effect of height diminished after controlling for this association. Thus, average height men partly achieved higher reproductive success by marrying at a younger age. On the basis of our literature review and our data, we conclude that men of average height most likely have higher reproductive success than either short or tall men.     

STREAM BASEFLOW PREDICTION BY CONVOLUTION OF ANTECEDENT RAINFALL EFFECTS1

ABSTRACT A method of stream baseflow prediction using a parallel drain theory and convolution techniques was developed. The infiltrating portions of several rain events were superimposed on the ground-water reserves and allowed to drain to the stream as individual baseflow responses. The convolution technique was used in summing the contributions from each rain event to the stream to give the total baseflow at any point in time. A single lumped parameter was adapted from a parallel drain analogy to represent the physical characteristics of a watershed. This parameter determines the time delay between a rainfall event and the resulting baseflow response. The procedure was applied to data from five watersheds. One year of records was used to find the best-fitting runoff delay coefficient, thus calibrating the response function which was subsequently applied to two test years to predict a dry weather low flow sequence. The agreement between predicted and observed flows was reasonably good, but marred by frequent minor rainfalls during the chosen dry periods. The application of the method should be much more successful in the western states where prolonged dry periods are common.     

Ecological implications of the presence of the tube-building polychaete <Emphasis Type="Italic">Lanice conchilega</Emphasis> on soft-bottom benthic ecosystems

The common tube-building polychaete Lanice conchilega is known as a habitat structuring species and can form dense aggregations. The effects of L. conchilega on the surrounding benthic community have received little attention, especially in subtidal areas. Therefore, the presence of L. conchilega in different habitats in the North Sea and its effect on the abundance, species richness, diversity and community structure in these habitats are evaluated in the present paper, based on data from the ICES North Sea Benthos Survey of 2000. Lanice conchilega has a wide geographical distribution and a low habitat specialization, but optimally occurs in shallow fine sands. In the present study, the presence of L. conchilega resulted in a density increase and a significant (positive) correlation of the benthos density with the density of L. conchilega. Furthermore, the species richness (number of species) increased with increasing density of L. conchilega. This trend was, however, not consistent: the number of species reached more or less an asymptotic value or even decreased after reaching a critical density of L. conchilega (>500–1,000 ind/m2), as observed in shallow fine sands. The same overall pattern was detected concerning the expected number of species. The N ₁-diversity index showed similar or slightly higher values in L. conchilega patches compared to patches without L. conchilega. From the results of the community analysis, it can be concluded that the species, which were responsible for the increase of the diversity, belonged to the overall species-pool of that habitat. The effects on density and diversity differed between the four discerned habitats (shallow muddy sand, shallow fine sand, shallow medium sand and deep fine sand), and were most pronounced in shallow fine sands. These patterns can be attributed to the habitat structuring capacity of L. conchilega. The mechanisms responsible for the increase of the habitat quality in patches of L. conchilega can be summarized as (1) changes in the hydrodynamics, (2) increases of the habitat stability and oxygen supply, and (3) a creation of habitat heterogeneity in a uniform environment. In this way, L. conchilega alters the habitat characteristics and affects other organisms, and can therefore even be considered as an ecosystem engineer. In other words, L. conchilega patches are responsible for an increased habitat quality in an otherwise uniform habitat, which results in a higher survival of the surrounding benthic species.     

Airborne exposure to wheat allergens: optimised elution for airborne dust samples

Well-validated methods for measuring airborne occupational allergens are essential for effective control and reduction of allergen exposures. For wheat flour allergens, specific immunoassays are available, but there is a need for optimisation and standardization of sample processing procedures. Wheat flour allergen elution and storage were studied using airborne dust samples collected in bakeries with a new parallel sampler. Forty-eight series of 9 parallel filters were subjected to extraction procedures varying in elution medium, shaking method, extraction vial, and centrifugation speed. Wheat allergens were measured with enzyme immunoassays, and the effect of various procedures evaluated by mixed regression analyses. The stability of the eluted allergens was assessed after storage for 20 days and 4 months at -20 degrees C, in the presence or absence of casein in the medium. Only the type of elution medium had significant effects on allergen recovery: addition of Tween-20 resulted in 3- to 100-fold increased levels, an effect that was most pronounced at low concentrations. Allergen levels in extracts were stable for at least 4 months at -20 degrees C, irrespective of the presence of casein in the medium. Addition of Tween-20 to the elution medium is essential for optimal extraction of wheat allergen. The recommended procedure further includes the use of conventional polystyrene tubes, simple shaking methods, and centrifugation after extraction. Wheat dust extracts in PBS-Tween can be stored frozen for at least 4 months, and addition of a stabilising protein is not required.     

PCDD/F and PCB in spruce forests of the Alps

PCDD/F and PCB concentrations in remote mountainous spruce stands of the Central European Alps show strong geographic variation. Independent of the matrix (0.5 year old needles, humus or mineral soil), the highest pollutant levels were always found at the lateral zones of the mountain range. High levels coincided with strong precipitation, particularly along the northern margin of the study region. The most volatile PCB congener propagated farther into the colder, drier central Alps than the heavier species. Matrices with different accumulation history (needles and humus) repeatedly reflected different spatial immission patterns. Consistent with its much longer exposure, pollutant levels in humus exceeded those of needles by up to two orders of magnitude. Needle contamination varied with altitude but the vertical trends were highly variable between transsects and changed between years, too.     

Expert knowledge-based assessment of farming practices for different biotic indicators using fuzzy logic

The study presented here describes a modeling approach for the ex-ante assessment of farming practices with respect to their risk for several single-species biodiversity indicators. The approach is based on fuzzy-logic techniques and, thus, is tolerant to the inclusion of sources of uncertain knowledge, such as expert judgment into the assessment. The result of the assessment is a so-called Index of Suitability (IS) for the five selected biotic indicators calculated per farming practice. Results of IS values are presented for the comparison of crops and for the comparison of several production alternatives per crop (e.g., organic vs. integrated farming, mineral vs. organic fertilization, and reduced vs. plow tillage). Altogether, the modeled results show that the different farming practices can greatly differ in terms of their suitability for the different biotic indicators and that the farmer has a certain scope of flexibility in opting for a farming practice that is more in favor of biodiversity conservation. Thus, the approach is apt to identify farming practices that contribute to biodiversity conservation and, moreover, enables the identification of farming practices that are suitable with respect to more than one biotic indicator.     

Investigation of uranium binding forms in selected German mineral waters

Cryogenic time-resolved laser-induced fluorescence spectroscopy was successfully used to identify uranium binding forms in selected German mineral waters of extremely low uranium concentrations (<2.0 μg/L). The measurements were performed at a low temperature of 153 K. The spectroscopic data showed a prevalence of aquatic species Ca₂UO₂(CO₃)₃ in all investigated waters, while other uranyl–carbonate complexes, viz, UO₂CO_3(aq) and UO₂(CO₃)₂ ^2?, only existed as minor species. The pH value, alkalinity (CO₃ ^2?), and the main water inorganic constituents, specifically the Ca²⁺ concentration, showed a clear influence on uranium speciation. Speciation modeling was performed using the most recent thermodynamic data for aqueous complexes of uranium. The modeling results for the main uranium binding form in the investigated waters indicated a good agreement with the spectroscopy measurements.     

Performance and dilemmas of urban containment strategies in the transformation context of Beijing

The implementation of urban containment policies is increasingly attracting attention in environment management. Rapid urban growth and the coexistence of decentralisation and marketisation challenge containment strategies that are implemented to control urban sprawl. This challenge is likely to be greater in a transformation country than in developed countries. This paper evaluates the performance of containment strategies in Beijing. The analysis shows that, to a large extent, containment strategies perform well; however, the decreased compactness of the fringes of the inter-suburban areas, caused by dispersed and illegal development, suggest that municipal containment strategies are being challenged by new trends towards local autonomy. Two similar dilemmas to those faced by developed countries are confronting those involved in the implementation of containment strategies in the current transformation process in Beijing: first, the municipal environmental goal might not be achieved by all local jurisdictions when local economic motivations are involved; and second, macro-scale containment policies are unlikely to control an urban sprawl fuelled by the growing power of market forces.