bluuebunny/crossref_metadata_2025 huggingface dataset:
MODIFYING DAM OPERATIONS TO RESTORE RIVERS: ECOLOGICAL RESPONSES TO TENNESSEE RIVER DAM MITIGATION
Authors: Bednarek Angela T. , Hart David D.
Published: June 2007

The Tennessee Valley Authority (TVA) initiated a Reservoir Releases Improvement Program in 1991 to increase minimum flows and improve water quality by modifying its dam operations. We compiled a comprehensive data set from ecological monitoring below nine dams to evaluate the effects of these modifications on physicochemical conditions and benthic macroinvertebrate assemblages. Abiotic and biotic data were collected in tailwaters by the TVA for three dam operation “treatments” (i.e., before any modifications, following flow modifications, and following both flow and dissolved oxygen [DO] modifications) at three different stations (Upper, Middle, and Lower) located at increasing longitudinal distances below each dam. Analysis of variance was used to test for differences in ecological conditions among treatments and stations.

Dam modifications had significant effects on both abiotic and biotic variables, and macroinvertebrate assemblages exhibited significant longitudinal differences. Yearly mean DO and mean minimum velocity increased following dam modifications. Across all sampling stations, macroinvertebrate family richness increased and the percentage of pollution‐tolerant macroinvertebrates (% Tolerant) decreased after dam modifications. Family richness also increased, and % Tolerant decreased, with increasing distance below the dams. Total abundance of macroinvertebrates increased after flow modifications and then decreased following changes in DO. The percentage of individuals belonging to the orders Ephemeroptera, Plecoptera, and Trichoptera (% EPT) increased following flow and DO modifications, but only at the Upper station. EPT family richness was unaffected by increased flow alone but increased following increases in both flow and DO. The design of the re‐operation “experiment” made it difficult to ascertain the relative contributions of flow and DO changes to the observed biotic responses, but flow alone appeared to have a smaller beneficial effect than the combined effects of flow and DO.
RANGE CONTRACTION MAY NOT ALWAYS PREDICT CORE AREAS: AN EXAMPLE FROM MARINE FISH
Authors: Shackell Nancy L. , Frank K. T. , Brickman D. W.
Published: June 2007

Our goal was to identify the core areas of six severely depleted marine fish species on the Scotian Shelf, Canada, using the theory of ideal free distribution (IFD). We tested for density‐dependent distribution on both regional and local scales. At the regional scale, a density‐dependent response was observed in the majority of populations. At the local scale, density was expected to remain stable in areas of high density and to change more rapidly in marginal areas, in response to changes in regional abundance. Lower local density responses were associated with areas of higher density, but deviations were evident, in part due to the magnitude of decline and in part due to fishing effects. Former areas of high density can be eroded if the population has severely declined. Fishing directed at an area of high density can cause local depletion when recolonization rates are low relative to the intensity of fishing. Thus, areas occupied during periods of low regional abundance do not of necessity reflect the historical array of core areas. We do not recommend the use of IFD theory to identify core areas of heavily exploited species. Instead, we recommend a precautionary approach that assumes the existence of low‐mixing populations that can be differentially affected by fishing. For species at risk, only data derived before significant population declines should be used to identify high‐density areas. Such areas would represent those with the potential to support higher densities as well as the historical array of subpopulations. Our study provides insight into the practical aspects of analyzing exploited species using ecological theory.
GIS‐BASED ESTIMATES OF FORMER AND CURRENT DEPRESSIONAL WETLANDS IN AN AGRICULTURAL LANDSCAPE
Authors: McCauley Lisa A. , Jenkins David G.
Published: June 2007

Before European settlement, 23% of Illinois (3.2 million of 14 million ha) was covered by wetlands. It is estimated that 90% of those wetlands were lost during conversion of the landscape to agriculture and urban use. Champaign County was one of the most extensively drained counties in Illinois, with 39–60% of original county area estimated to have been drained. Current and future efforts to conserve and restore wetlands would benefit from information on the number and distribution of former wetlands. We used GIS to estimate the spatial extent, density, pattern, and sizes of former and extant depressional wetlands in Champaign County. We derived several models of former wetlands; all models used hydric soils but varied by using Digital Raster Graphics (DRG), 30‐m Digital Elevation Models (DEM), or Digital Orthophotography Quarter Quadrangles (DOQ). We also combined the DRG and DEM models, and we conducted visual field surveys for saturated or ponded conditions to test the models. The DRG model was conservative: it identified fewer and larger wetlands than the DEM model (the DOQ model was judged inadequate). Depending on the model selected, we estimated that 1077–4090 depressional wetlands formerly existed in the county, and that 78.6–91.6% were drained, accounting for 1108–2777 ha of lost wetland habitat in Champaign County alone. Thus, depressional wetlands accounted for the vast majority of historical wetland loss and should be a priority for wetland restoration efforts. Spatial pattern among wetlands also changed: an organism adapted to the former landscape had >50% probability of reaching another wetland within 260 m: today that same species faces a 7.8% probability at that distance. The modern landscape of Champaign County (and others like it) poses potential risk for remaining wetland metapopulations, and GIS models of precise former wetlands locations can be a valuable initial tool for wetland conservation and restoration efforts.
MARINE RESERVE DESIGN AND THE EVOLUTION OF SIZE AT MATURATION IN HARVESTED FISH
Authors: Baskett Marissa L. , Levin Simon A. , Gaines Steven D. , Dushoff Jonathan
Published: June 2007

By significantly changing size‐dependent mortality, fisheries can cause rapid evolution toward earlier maturation in harvested species. Because earlier maturation negatively affects biomass yield and sustainability, ignoring evolutionary changes could significantly reduce the success of fisheries management policy. With a quantitative genetic model of size at maturation that incorporates phenotype plasticity, we examine the impact of different management strategies including traditional effort control and Marine Protected Areas (MPAs). After verifying the model's accuracy, using historical trajectories for size at maturation in cod (Gadus morhua), we test model predictions under different management schemes with life history parameters for red snapper (Lutjanus campechanus) and two rockfish species (Sebastes paucispinis and S. ruberrimus). The model results show that no‐take MPAs can protect against strong fisheries‐based selection for earlier maturation. The potential to protect against anthropogenic selection declines with increasing fragmentation of reserves to networks of small reserves. Accounting for the evolution of size at maturation increases the predicted biomass contribution from MPA populations to harvested populations. Traditional management approaches, such as adjustments to harvest rate and maximum size limits, can lead to equivalent protection against anthropogenic selection and equivalent or greater long‐term biomass yield than establishing MPAs; however, the protection and yield from establishing no‐take MPAs appears more robust to uncertainty.
ASSESSING AND MONITORING ECOLOGICAL COMMUNITY HEALTH IN MARINE SYSTEMS
Authors: Hewitt J. E. , Anderson M. J. , Thrush S. F.
Published: June 2007

The increased potential for long‐term degradative change associated with large‐scale diffuse impacts in urban marine environments highlights the need to develop methods for assessing the ecological significance of any observed changes. This study defines “health” on the basis of the range of communities observed along gradients of anthropogenic impacts. This definition identifies both acute effects and broader scale degradation in community structure. Three multivariate constrained ordination techniques were used to assess changes in communities occurring along an anthropogenic disturbance gradient of stormwater pollution in two different habitats (estuaries and harbors). All three techniques detected changes, even when historical data sets, not specifically designed for the purpose, were utilized. Comparison with five diversity indices suggested that the multivariate approach was more successful in defining change and, thus, ecological health. Moreover, the information can easily be examined for changes in individual species, or for changes in function, trophic status, or biomass/size structure, improving interpretation of the ecological consequences of change. As this multivariate approach allows for monitoring community composition to determine whether sites are improving or degrading over time, it would be useful for aiding management decisions and assessing the efficiency of management actions. While this study occurred in one region only, the approach should be able to be utilized in other marine (or freshwater or terrestrial) systems where commensurable regional‐scale multivariate databases exist.
REGIONAL LEGACIES OF LOGGING: DEPARTURE FROM PRESETTLEMENT FOREST CONDITIONS IN NORTHERN MINNESOTA
Authors: Friedman Steven K. , Reich Peter B.
Published: June 2007

Forests in the Great Lakes region of Canada and the United States have been important timber producing resources for more than 100 years. Logging and fire suppression have caused major, but unquantified change in those forests, which includes both the magnitude of compositional change and its spatial patterns. Hence, a spatially explicit regional‐scale change analysis was conducted using General Land Office Survey records from the late 1800s and the 1990 U.S. Forest Service Inventory and Analysis Survey, for a 3.2 million hectare study area in northeastern Minnesota, USA. These data document altered species abundance, proportional basal area, and spatial distribution patterns. Regionally, the proportionally most abundant species shifted from the presettlement period (spruce, 21%; larch, 15%; and paper birch, 15%) to aspen (30%), spruce (16%), and balsam fir (16%) in 1990. In terms of proportional basal area dominance, white pine declined from 20% to 5%, birch from 16% to 13%, spruce from 14% to 9%, and larch from 12% to 2%, while aspen increased from 8% to 35%. Based on ordination of species abundance and proportional basal area, physiographic zones varying in geology and hydrology were characterized by different species composition in the 19th century and experienced largely parallel rather than convergent shifts in community composition since that time.

Maps were developed for the regional study area using a 10 × 10 km spatial resolution to document spatial patterns of species proportional basal area. White pine co‐dominated (was ranked first or second in proportion of basal area) 45% of the 253 100‐km2 presettlement zones, but none of the 1990 zones. Forest zones co‐dominated by red pine, jack pine, and larch also largely disappeared. These forests were largely supplanted by aspen co‐dominated communities, which accounted for 82% of the 1990 forest zones and represent diminished regional landscape diversity. Although the same 11 species made up the 1990 as well as the 19th century forest, change in their relative abundance and dominance was profound such that 85% of the 253 zones now contain community types (i.e., dominant species pairs) that did not dominate anywhere in the presettlement era.
GPS MEASUREMENT ERROR INFLUENCES ON MOVEMENT MODEL PARAMETERIZATION
Authors: Jerde Christopher L. , Visscher Darcy R.
Published: June 2007

Global positioning system (GPS) technology has increased the accuracy and efficiency in recording animal locations and has provided data used to parameterize movement models. Although numerous studies have investigated the quality and accuracy of location data associated with different brands of GPS collars, none of these studies has investigated the influence of measurement error on the parameters used to create movement models. We used Monte Carlo simulation to quantify the measurement error for estimates of turning angle and step length as a function of distance between consecutive locations. We show that estimates of turning angle and step length are accurate only when the distance between two locations is large relative to the measurement error. Estimates of turning angle are particularly susceptible to error for short step lengths. The consequences of choosing poor data‐collecting schedules are discussed, and suggestions for designing appropriate data‐collecting schedules are provided.
FROM FOREST TO FARMLAND: HABITAT EFFECTS ON AFROTROPICAL FOREST BIRD DIVERSITY
Authors: Waltert Matthias , Bobo K. Serge , Sainge N. Moses , Fermon Heleen , Mühlenberg Michael
Published: June 2007

Although the Guinea–Congolian rain forest region is an important focal point for conservation in Africa, very little information is available on the effects of forest modification and land use on the region's biodiversity. We studied bird communities and vegetation characteristics in 24 sampling stations distributed over two near‐natural forests (near‐primary forest, secondary forest), and two land use types (agroforestry, annual cultures) in the lowlands of the Korup region, Cameroon. Repeated sampling was used to establish near‐complete inventories of bird assemblages for each site. Despite a 90% average drop in tree basal area from forest to farmland, overall bird species richness did not decrease significantly with increasing habitat modification. However, different groups of birds responded in different ways. Frugivorous and omnivorous bird species richness did not differ between habitats, whereas richness in granivorous, flower‐visiting, and nonbreeding species was higher in land use systems compared to forests. In contrast, insectivorous birds, especially terrestrial and large arboreal foliage gleaning insectivores, and ant followers showed a declining species richness from forest to farmland. Also, richness in species of those restricted to the Guinea–Congolian forest biome and of the family Pycnonotidae showed a pronounced decline with increasing habitat modification. Species richness of overall insectivores, terrestrial insectivores, large‐ and medium‐sized arboreal foliage gleaners, ant followers, as well as pycnonotids and biome‐restricted species, were strongly or even very strongly positively correlated with overstory tree density and, in most cases, also with basal area. In contrast, tree density and basal area were strongly negatively correlated with species richness of nonbreeding visitors and flower‐visiting bird species. Species composition was most distinct between near‐primary forest and annual culture sites, and the abundance of 23 out of 165 species was affected by habitat, suggesting considerable partitioning of habitat niches along the habitat gradient. Our results stress the importance of tree cover in tropical land use systems for the maintenance of resident forest bird populations and confirm that natural forest management is more beneficial for global bird conservation compared to other forms of forest exploitation, including agroforestry systems.
DISRUPTION OF WEED BIOLOGICAL CONTROL BY AN OPPORTUNISTIC MIRID PREDATOR
Authors: Hunt-Joshi Tamaru R. , Root Richard B. , Blossey Bernd
Published: June 2007

Species cascades involving generalist predators, biological control herbivores, and invasive plants have great potential to disrupt weed biological control efforts and the ability of herbivores to limit plant invasions. We found that Plagiognathus politis, a mirid bug typically reported as herbivorous and as an agricultural pest, was an avid opportunistic predator of Galerucella calmariensis, an herbivore introduced to North America for biological control of Lythrum salicaria (purple loosestrife). In field cages, adult and immature mirid bugs consumed large numbers of eggs and young larvae of G. calmariensis in addition to feeding on purple loosestrife leaves. We document a species cascade that benefited purple loosestrife; in mesocosms, mirid predation on G. calmariensis allowed purple loosestrife to maintain greater leaf, stem, and reproductive biomass than without predators. In field cages, however, top‐down effects were weaker, probably because G. calmariensis had a temporal refuge from predation. An early‐season window of low predation pressure (where beetle eggs hatched and eclosed earlier than mirids) allowed G. calmariensis to establish and persist within our field cages. Our experiments show that, although mirids initiated a clear species cascade in potted plant mesocosms, this was less evident in field cages, probably due to increased spatial and temporal complexity. However, since mirid predators consume large numbers of eggs and larvae, effectiveness of G. calmariensis as a biological control agent could be greatly suppressed when release sites are inhabited by P. politis. Interference of weed biological control by opportunistic generalist predators is particularly important to document because it is usually subtle and may remain unrecognized even if release efforts fail. However, despite this, herbivore establishment rates in weed control programs could be greatly improved through repeated large‐scale releases that satiate potential predators, thus allowing herbivores to escape their limiting influence.
LAND USE, WATER CHEMISTRY, AQUATIC VEGETATION, AND ZOOPLANKTON COMMUNITY STRUCTURE OF SHALLOW LAKES
Authors: Dodson Stanley I. , Lillie Richard A. , Will-Wolf Susan
Published: June 2007

Landscape–lake interactions, including anthropogenic effects in modern human‐dominated landscapes, are essential elements of our understanding of aquatic community ecology. This study links land use (six categories) to the aquatic environment (30 water chemistry, lake morphology, and vegetation variables) and to zooplankton community richness (32 common taxa) and composition in 73 small and shallow lakes of southeastern Wisconsin, USA. The sites differed most according to two environmental variables (principal components analysis [PCA] ordination): the presence/absence of riparian vegetation and the water source (whether ground or atmospheric). Shallow lakes in different land use categories (reference, urban, and agricultural) differed significantly in terms of the two major environmental variables, especially presence of riparian and aquatic vegetation.

Reference sites were characterized by the most vegetation and the highest zooplankton richness. Agricultural sites with wide riparian vegetative buffer strips (>30 m) had significantly more zooplankton taxa than agricultural lakes with narrow buffer strips. A nonmetric multidimensional scaling (NMS) ordination of zooplankton community composition suggested a single community among land use categories, with some variation related to vegetation and the water source. The first NMS axis was correlated with PCA1 axis (vegetation) and with zooplankton taxon richness, and the second axis was correlated with PCA2 (water source). The third axis was not strongly correlated with any of the measured environmental factors, suggesting that an unmeasured factor related to disturbance was also important in determining taxon composition. Our analysis supports the hypothesis that zooplankton community structure (taxon richness and composition) is indirectly associated with land use, via the effect of land use on vegetation and the hydrological continuum.
EARLIER RECRUITMENT OR EARLIER DEATH? ON THE ASSUMPTION OF EQUAL SURVIVAL IN RECRUITMENT STUDIES
Authors: Cam Emmanuelle , Cooch Evan G. , Monnat Jean-Yves
Published: June 2007

In species with deferred breeding, the population can be viewed as composed of phenotypes with different underlying age of first breeding defined at birth. The distribution of underlying age of first breeding within cohorts and the realized distribution of age of recruitment in individuals that survived from birth to first breeding (assessed in the breeding segment of the population) may differ. Realized age of recruitment is governed by the product of two demographic components: [local survival probability from birth to age i − 1] × [transition probability from the “prebreeder” state to the “breeder” state between age i − 1 and i]. The usual approach to gain insight into selective pressures shaping age of recruitment is to address covariation of realized age of first breeding with population size or social and environmental factors. Ideally, one should also conduct comparisons among groups of individuals encountering different conditions at a given age as prebreeders. However, in many species with deferred breeding, individuals are not encountered between birth and first breeding. Consequently, approaches to estimating recruitment probability in the absence of data from prebreeders have been developed. Some of these measures of recruitment ignore variation in the size of the pool of prebreeders among groups (as opposed to transition probability). Unless survival before full recruitment is known to be identical in the groups, inferences about the causes of variation in realized age of first breeding among groups are difficult: such differences may result from differences in survival probability before all the individuals make the transition between states.

We assessed the consequences of differences in prebreeding survival among groups on realized age‐specific recruitment probability using numerical simulations. Depending on the specific scenario, realized age‐specific breeding proportions were delayed or advanced compared to those expected according to the true underlying age‐specific transition probabilities. We consider an example of this problem using data from a population of a seabird species, the kittiwake (Rissa tridactyla), where data from prebreeders and breeders were available. Consistent with results from our numerical simulations, we show that transition probabilities directly estimated (the underlying local recruitment probabilities) and those derived from analysis of data from the breeding segment of the population are different.
THE CREATION OF ALTERNATIVE STABLE STATES IN THE SOUTHERN BOREAL FOREST, QUÉBEC, CANADA
Authors: Jasinski J. P. Paul , Payette Serge
Published: June 2007

The southernmost spruce–lichen woodlands in the Parc des Grands‐Jardins, Québec, Canada, are situated 500 km south of their usual range in the northern lichen woodland zone. Their co‐occurrence within a spruce–moss forest matrix suggests the existence of alternative stable states. We investigate the possibility of these spruce–lichen woodlands as an alternative stable state along with the factors contributing to their origin and spatiotemporal distribution. Analysis of plant macrofossils, charcoal, head capsules of defoliating insects, and pollen were used along with vegetation surveys to reconstruct the past and present disturbance dynamics along an east–west transect, corresponding to a precipitation and fire frequency gradient. At each site, spruce budworm head capsules were found preceding the charcoal layer delineating the shift to spruce–lichen woodland, demonstrating the compound disturbance (insect–fire) origin of the lichen woodlands. Moss forests previously occupied all lichen woodland sites, with the oldest record starting ca. 8300–9400 yr BP. A change to a higher fire frequency around 2500 yr BP was evident in the lichen woodland zone of the park. A lower fire frequency west of the lichen woodland zone likely is a result of orographic precipitation. While the spruce budworm affects the entire region, lichen woodlands are found exclusively within an increased fire frequency zone. Thus, it is the superimposition of these two disturbance factors that is responsible both for their creation and spatial distribution. Lichen woodland inception dates range between 580 and 1440 yr BP, demonstrating that these lichen woodlands have maintained their open structure with time and have not transformed into closed forests. Their persistence, along with their previous moss forest histories and current occurrence adjacent to closed moss forests, indicate that they are an alternative stable state to the spruce–moss forests and not a successional stage. In contrast to other examples of reported alternative stable states, this one is a result of natural disturbances inherent to the system and not anthropogenic impacts.
MICROBE‐MEDIATED PLANT–SOIL FEEDBACK CAUSES HISTORICAL CONTINGENCY EFFECTS IN PLANT COMMUNITY ASSEMBLY
Authors: Kardol Paul , Cornips Nelleke J. , van Kempen Monique M. L. , Bakx-Schotman J. M. Tanja , van der Putten Wim H.
Published: June 2007

Plant–soil feedback affects performance and competitive ability of individual plants. However, the importance of plant–soil feedback in historical contingency processes and plant community dynamics is largely unknown. In microcosms, we tested how six early‐successional plant species of secondary succession on ex‐arable land induced plant‐specific changes in soil community composition. Following one growth cycle of conditioning the soil community, soil feedback effects were assessed as plant performance in soil of their own as compared to soil from a mixture of the other five early‐successional species. Performance was tested in monocultures and in mixed communities with heterospecific competition from mid‐successional species. The role of soil microorganisms was determined by isolating the microbial component from the soil community, re‐inoculating microorganisms into sterilized substrate, and analyzing plant biomass responses of the early‐ and mid‐successional species.

Plant–soil feedback responses of the early‐successional species were negative and significantly increased when the plants were grown in a competitive environment with heterospecifics. In monocultures, three early‐successional species experienced negative feedback in soil with a history of conspecifics, while all early‐successional species experienced negative feedback when grown with interspecific competition. Interestingly, the nonnative forb Conyza canadensis showed the weakest soil feedback effect. Biomass production of the early‐successional plant species was profoundly reduced by the microbial inocula, most strongly when exposed to inocula of conspecific origin. Molecular characterization of the fungal and bacterial rhizosphere communities revealed a relationship between plant biomass production and the composition of the dominant fungal species. Furthermore, our results show that, in early secondary succession, the early‐successional plant species induce changes in the soil microbial community composition that cause historical contingency effects in dominance patterns of mid‐succession plant communities.

We conclude that feedback between early‐successional plant species and soil microorganisms can play a crucial role in breaking dominance of early‐successional plant communities. Moreover the influences on soil microorganism community composition influenced plant community dynamics in the mid‐successional plant communities. These results shed new light on how feedback effects between plants and soil organisms in one successional stage result in a biotic legacy effect, which influences plant community processes in subsequent successional stages.
LIFE HISTORY TYPE AND WATER STRESS TOLERANCE IN NINE CALIFORNIA CHAPARRAL SPECIES (RHAMNACEAE)
Authors: Pratt R. B. , Jacobsen A. L. , Golgotiu K. A. , Sperry J. S. , Ewers F. W. , Davis S. D.
Published: June 2007

Chaparral species of California, USA, exhibit three life history types in response to fire: non‐sprouters (NS), facultative sprouters (FS), and obligate sprouters (OS). Adult non‐sprouters are killed by fire; thus populations reestablish only through fire‐stimulated seed germination and seedling recruitment. Facultative sprouters reestablish by both vegetative sprouting and seed germination. Obligate sprouters reestablish only by vegetative sprouting and do not recruit seedlings post‐fire. Previous data suggest that post‐fire NS and FS seedlings reestablish as open‐canopy gap specialists, whereas OS seedlings primarily reestablish in deep shade during fire‐free intervals. Their non‐refractory seeds are killed by fire. We hypothesized that these differences in life history, compared within the same taxonomic group, would result in a range of relative resistance to water stress such that NS > FS > OS. To test our hypothesis, we estimated resistance to water stress using resistance to xylem cavitation (the water potential at 50% loss in hydraulic conductivity; Ψ50) for stems and roots in nine species of the family Rhamnaceae: Ceanothus megacarpus, C. crassifolius, and C. cuneatus (NS); C. spinosus, C. oliganthus, and C. leucodermis (FS); and Rhamnus ilicifolia, R. crocea, and R. californica (OS). Stems of NS species displayed greater resistance to cavitation (Ψ50 = −8.38 ± 0.47 MPa) compared to both the FS (Ψ50 = −5.07 ± 0.55 MPa) and OS species (Ψ50 = −5.99 ± 0.38 MPa), whereas FS and OS species were not different. For roots, the general pattern was the same, but roots were generally less cavitation resistant than stems. A hydraulic model predicted that water uptake in OS species was limited by extensive cavitation in vulnerable root xylem, consistent with a reliance on deep soil water. Water uptake in cavitation‐resistant NS species was most limited by soil hydraulic resistance, consistent with maximizing extraction of shallow soil water. These results suggest a link between life history and water stress tolerance in chaparral.
Research Testing of Tailored Interventions
Authors: Enderlin Carol A. , Richards Kathy C.
Published: June 2007

The purpose of this article is to offer rationale to support the argument for research testing of tailored interventions. The individualization of nursing interventions is used as a basis for discussion of the emergent need to test tailored interventions at the research rather than practice level. Both justification of efficacy and feasibility support the research testing of tailored interventions, in support of an evolving nursing process. In order to retain its patient-centered focus and yet meet scientific standards for practice, nursing must evaluate the individualization of care through more theory-based and systematic research processes. The testing of tailored interventions at the research level would provide a means to achieve these ends.
Beef Cattle Production, Nutritional Quality, and Economics of Windrowed Forage vs. Baled Hay During Winter
Authors: Nayigihugu V. , Schleicher A. D. , Koch D. W. , Held L. J. , Flake J. W. , Hess B. W.
Published: June 2007

Production expenses associated with harvesting and feeding hay account for a large proportion of annual production costs for ruminant livestock systems. A 2‐yr experiment compared windrow grazing, as a potential method to reduce winter cost, with feeding baled hay to beef cows. Two irrigated meadows (16.2 and 10.1 ha) consisting of a mixture of ‘Garrison’ creeping foxtail (Alopecurus arundinaceus Poir.) and other introduced and native forage species were either baled and removed or windrowed and left in place 26 Aug. 1999 and 27 July 2000. Forage samples were collected from windrows and baled hay at harvest and then monthly until January. Beginning in November 1999 and 2000, 64 and 54 pregnant cows, respectively, were assigned to windrowed or baled forage for 42 d. Forage acid detergent fiber (ADF) was greater (P < 0.01) in 1999 and neutral detergent fiber (NDF) tended to be greater (P = 0.09) in 2000 for windrowed than baled forage. Crude protein (CP) tended to be greater in windrowed (100 g kg−1) than baled (93 g kg−1) forage in 2000 (P = 0.08), but was similar (windrows, 89 g kg−1; bales, 90 g kg−1) in 1999 (P = 0.11). In 1999, cows offered windrowed forage had greater average daily gain (ADG = 1 kg d−1; P = 0.04) and body condition score (BCS = 5.5; P = 0.02) than cows fed baled forage [ADG = 0.66 kg−d; BCS = 5.3]. In 2000, cattle offered windrows (−0.42 kg−d) had lower (P = 0.03) ADG compared with cattle fed baled forage (0.1 kg−d). Windrow grazing was less economical under the study and management conditions than bale feeding due to high cost of watering livestock and forage wastage.
Comparison between Organic and Mineral Fertilization for Soil Fertility Levels, Crop Macronutrient Concentrations, and Yield
Authors: Herencia J. F. , Ruiz‐Porras J. C. , Melero S. , Garcia‐Galavis P. A. , Morillo E. , Maqueda C.
Published: June 2007

Interest in soil organic fertilization has grown appreciably in recent years; however, few studies have been performed in greenhouses. A comparative study of organic vs. mineral fertilization in a greenhouse has been conducted for 9 yr in a calcareous loamy soil classified as Xerofluvent in the Guadalquivir River Valley, Seville, Spain. The nutrient availability in the soil, macronutrient concentration in the edible part of the plants, and yield were examined. The organic fertilizer used was vegetal compost and green residue of previous crops that came from the experimental farm and did not depend on external inputs. The use of organic fertilizer resulted in higher soil organic matter, soil N content, and available P and K. However few differences were found in the macronutrient concentration in the edible part of the crops, independent of the type of fertilization. The nitrate concentration in the edible parts was significantly lower for the crops grown in the organically fertilized plots. Crop yield was not statistically different between fertilizer treatments. This study demonstrated that long‐term use of organic compost in greenhouse soil improved soil fertility and produced similar yields and nutrient composition in the edible portion of crops compared with mineral fertilization.
Placement of Preplant Liquid Nitrogen and Phosphorus Fertilizer and Nitrogen Rate Affects No‐Till Wheat Following Different Summer Crops
Authors: Kelley K. W. , Sweeney D. W.
Published: June 2007

Because of improved equipment technology, many producers in the eastern Great Plains are planting winter wheat (Triticum aestivum L.) no‐till (NT) into previous crop residues, but management of fertilizer N and P remains critical. This field study was conducted from 1998 through 2003 in southeastern Kansas on a Parsons silt loam soil (fine, mixed, thermic, Mollic Albaqualf). The objectives were to determine effects and interactions of previous crop [corn, Zea mays L.; grain sorghum, Sorghum bicolor (L.); and soybean, Glycine max (L.) Merr.], preplant placement method of liquid N–P fertilizer [subsurface‐knife (KN), surface‐band (SB), and surface‐broadcast (BC)], and fertilizer N rate (22, 45, 90, and 134 kg N ha−1) on NT winter wheat yield, yield components, and nutrient uptake in a 2‐yr cropping rotation. Wheat yields averaged 3.73, 3.56, and 2.97 Mg ha−1 following soybean, corn, and grain sorghum, respectively. However, as fertilizer N rate increased, yield differences between previous crops decreased. Grain yields also were influenced by placement of N–P fertilizer, averaging 3.68 Mg ha−1 for KN, 3.40 Mg ha−1 for SB, and 3.19 Mg ha−1 for BC. Plant and grain N responses indicated that grain yield differences were primarily related to greater immobilization of both fertilizer and soil N following grain sorghum, compared with soybean and corn, and to better utilization of KN N–P than surface‐applied. Fertilizing with greater N rates applied as a subsurface band, especially if following grain sorghum, may be necessary to maximize NT wheat yield potential in the eastern Great Plains.
Influence of Planting Date and Weed Interference on Sweet Corn Growth and Development
Authors: Williams Martin M. , Lindquist John L.
Published: June 2007

Crop planting date and canopy density influence interactions between weeds and sweet corn (Zea mays L.); however, little is known about sweet corn growth response to weed interference. Field studies were conducted in 2004 and 2005 near Urbana, IL, to quantify the influence of planting date and weed interference on growth of sweet corn height, leaf area, aboveground biomass, and phenological development. Crop growth response to weed interference (presence or absence) was determined for sweet corn planted early May (EARLY) and late June (LATE). Dominant weed species included barnyardgrass [Echinochloa crus‐galli (L.) Beauv.], common lambsquarters (Chenopodium album L.), common purslane (Portulaca oleracea L.), green foxtail [Setaria viridus (L.) Beauv.], redroot pigweed (Amaranthus retroflexus L.), and velvetleaf (Abutilon theophrasti Medicus) at densities ranging from 95 to 256 plants m−2. Weed interference reduced sweet corn's absolute height growth rate, maximum leaf area index (LAI), absolute LAI growth rate, with some of the largest effects on crop growth observed in the EARLY planting date. Silk emergence was delayed by weeds for EARLY planted sweet corn, but not LATE. Moreover, the LATE planting date resulted in 9% taller crop plants with 36% lower maximum LAI. Relative to an EARLY planting date, lower yield losses due to weeds for LATE sweet corn correspond to greater resiliency of crop growth and silk emergence to weed interference.
Microcontact Processing for Microtechnology and Biology
Authors: Delamarche Emmanuel
Published: June 2007

Processes occurring on surfaces are ubiquitous both in everyday life and in the research activities of many scientists. When these processes can be mastered with sufficient spatial resolution, they are employed for the manufacture of electronic devices, displays, data storage equipment,
optical equipment, sensors, diagnostic devices, etc. A new class of surface-patterning techniques in which chemistry is localized by means of micropatterned stamps or microfluidic elements is emerging. These techniques might be increasingly applied to complement 'conventional' microfabrication
techniques and to create high-performance, miniaturized bio-analytical systems.
Discovery of Highly Potent and Selective CXCR4 Inhibitors Using Protein Epitope Mimetics (PEM) Technology
Authors: Lederer Alexander , Robinson John A. , Moehle Kerstin , Klimkait Thomas , Hamy François , Brondani Vincent , Lociuro Sergio , Obrecht Jean-Pierre , Vrijbloed Jan Willem , Ludin Christian , Gombert Frank O. , Brianza Federico , Zumbrunn Jürg , Mukherjee Reshmi , Romagnoli Barbara , Henze Heiko , DeMarco Steven J. , Obrecht Daniel
Published: June 2007

Novel, highly potent CXCR4 inhibitors with good pharmacokinetic properties were obtained by applying PEM technology starting from the naturally occurring ?-hairpin peptide polyphemusin II. The design involved incorporation of key residues from polyphemusin II into a macrocyclic
template-bound ?-hairpin mimetic. Using a parallel synthesis approach, the potency and ADME properties of the mimetics were optimized, resulting in CXCR4 inhibitors such as POL2438 and POL3026. Their activities were confirmed in a series of in vitro HIV-1 infection assays. Besides
high selectivity for CXCR4, POL3026 had excellent plasma stability and favorable pharmacokinetic properties in dogs. In a murine model POL3026 was highly efficacious in hematopoietic stem cell mobilization. Hence, PEM-based CXCR4 inhibitors have the potential to become therapeutic agents for
the treatment of HIV infections (as entry inhibitor), cancer (e.g. for inhibition of metastasis), stem cell transplant and inflammation.
Alcohols and Water as Reducing Agents in Radical Reactions
Authors: Pozzi Davide , Renaud Philippe
Published: June 2007

The radical reduction of B-alkylcatecholboranes into alkanes using alcohols and water as hydrogen atom source is described. This process involves a completely unexpected mechanism: the alcohol (or water) complexed to a borate derivative acts as a reducing agent. The complexation activates
the alcohol resulting in a decrease of the O–H bond dissociation energy. This approach offers promising opportunities for the development of tin-free radical reducing agent. Closely related reports from the recent literature involving boron and titanium derivatives are also presented.
Electron Transfer Properties from Atomistic Simulations and Density Functional Theory
Authors: VandeVondele Joost , Sulpizi Marialore , Sprik Michiel
Published: June 2007

Marcus theory of electron transfer is the quintessential example of a successful theory in physical chemistry. In this paper, we describe the theoretical approach we have adopted to compute key parameters in Marcus theory. In our method, based on molecular dynamics simulations and density
functional theory, the redox center and its environment are treated at the same level of theory. Such a detailed atomistic model describes specific solvent–solute interactions, such as hydrogen bonding, explicitly. The quantum chemical nature of our computations enables us to study the
effect of chemical modifications of the redox centers and deals accurately with the electronic polarization of the environment. Based on results of previous work, we will illustrate that quantitative agreement with experiment can be obtained for differences in redox potentials and solvent
reorganization energies for systems ranging from small organic compounds to proteins in solution.
Biphasic Catalysis in Aqueous and Ionic Liquid Media
Authors: Fellay Céline
Published: June 2007

An overview of recent developments from the Laboratory of Organometallic and Medicinal Chemistry at the EPFL in biphasic catalysis, involving aqueous solutions and ionic liquids, and in CO2 reduction is presented. Progress in the use of ionic liquids, either by catalyst modification
or by the design of task-specific ionic liquids is described. The application of high pressure methods to provide fundamental data and mechanistic insights into reactions and processes in these solvents is also described.
Preparation of Star-Shaped Pentapyridyl Ligands for the Formation of Giant Fullerene-Like Molecules by Coordination Chemistry
Authors: Jarrosson Thibaut , Oms Olivier , Bernardinelli Gérald , Williams Alan F.
Published: June 2007

We present the syntheses of two new star-shaped penta-ligands containing five pyridyls, which may be considered as starting materials for the preparation of fullerene-like molecules by coordination chemistry. One synthetic strategy is similar to that used for pentaphenylferrocenyl di-tert-butylphosphine.
The penta-4-pyridyl derivative was prepared in two steps from ferrocene. A second strategy involving a Suzuki cross-coupling reaction with a penta-bromoaryl scorpionate is presented.
New Trends in Fast Liquid Chromatography
Authors: Nguyen Dao T.-T. , Guillarme Davy , Rudaz Serge , Veuthey Jean-Luc
Published: June 2007

Analytical laboratories are currently interested in enhancing overall productivity by increasing sample throughput and reducing analysis time. Different approaches are proposed in liquid chromatography (LC) to perform fast or ultra-fast separations with cycle times of less than 5 or
1 min, respectively. Among these approaches, the use of monolithic supports, high temperature LC (HTLC), short columns and ultra-performance LC (UPLC) are described and compared in this study. A comparison of the above LC approaches is presented through Knox curves and pressure plots based
on experimental data. Fast separations of pharmaceutical compounds are presented in order to illustrate the interest of these techniques and compare them with conventional LC separations.
Mimetics of Sialyl Lewisx: The Pre-Organization of the Carboxylic Acid is Essential for Binding to Selectins
Authors: Titz Alexander , Ernst Beat
Published: June 2007

Selectins play a key role in leukocyte trafficking during the inflammatory response of the organism, i.e. the recruitment and extravasation of leukocytes from the blood stream into inflamed tissue. Antagonizing the interaction of selectins with their physiological ligands was
shown to be a validated approach for the treatment of inflammatory disorders like rheumatoid arthritis, stroke or reperfusion injuries. Although numerous research efforts to identify small molecule selectin antagonists have been reported, no successful drug has been identified so far. This
mini-review describes selectin antagonists, where the N-acetylneuraminic acid moiety of the natural ligand sialyl Lewisx is replaced by mimetics containing the essential carboxylic acid function. The prerequisite of a pre-organization of the carboxylate in the bioactive conformation
is discussed.
A Few Bad Apples or a Spoiled Barrel? The CDU Party Finance Scandal Five Years Later
Authors: Clemens Clay
Published: June 2007

It was the biggest political scandal in postwar German history. As revelation followed revelation in late 1999, the Christian Democratic Union (CDU) party finance (Parteifinanz) affair tarnished careers, most notably those of former chancellor Helmut Kohl and, separately, his longtime heir apparent Wolfgang Schäuble. When both fell, their party gained a new cadre of leaders. Most analysts expected the fallout ultimately to spread much further, fatally crippling the CDU and perhaps destroying it altogether. Voices could be heard to the effect that this scandal was on the same scale as one that rocked Italy a decade earlier, when the "Clean Hands" investigation unearthed massive evidence of bribery and corruption.
The Development of Light‐Emitting Dendrimers for Displays
Authors: Burn P. L. , Lo S.‐C. , Samuel I. D. W.
Published: June 2007

Dendrimers are now an important class of light‐emitting material for use in organic light‐emitting diodes (OLEDs). Dendrimers are branched macromolecules that consist of a core, one or more dendrons, and surface groups. The different parts of the macromolecule can be selected to give the desired optoelectronic and processing properties. The first light‐emitting dendrimers were fluorescent but more recently highly efficient phosphorescent dendrimers have been developed. OLEDs containing light‐emitting dendrimers have been reported to have external quantum efficiencies of up to 16 %. The solubility of the dendrimers opens the way for simple processing and a new class of flat‐panel displays. In this Review we show how the structure of the light‐emitting dendrimers controls key features such as intermolecular interactions and charge transport, which are important for all OLED materials. The advantages of the dendrimer architecture for phosphorescent emitters and the way the structure can be varied to enhance materials performance and device design are illustrated.