bluuebunny/crossref_metadata_2025 huggingface dataset:
DETERMINING NATURAL SCALES OF ECOLOGICAL SYSTEMS
Authors: Habeeb Rebecca L. , Trebilco Jessica , Wotherspoon Simon , Johnson Craig R.
Published: June 2007

A key issue in ecology is to identify the appropriate scale(s) at which to observe trends in ecosystem behavior. The characteristic length scale (CLS) is a natural scale of a system at which the underlying deterministic dynamics are most clearly observed. Any approach to estimating CLSs of a natural system must be able to accommodate complex nonlinear dynamics and must have realistic requirements for data. Here, we compare the robustness of two methods to estimate CLSs of dynamical systems, both of which use attractor reconstruction to account for the complex oscillatory dynamics of ecological systems. We apply these techniques to estimate CLSs of spatial multispecies systems of varying complexity, and show that both methods are robust for the simplest system, but as model complexity increases, the Pascual and Levin metric is more robust than that of Keeling et al. Both methods demonstrate some sensitivity to the choice of species used in the analysis, with closely connected species producing more similar CLSs than loosely connected species. In this context, connectivity is determined both by the topology of the interaction network and spatial organization in the system. Notably, systems showing complex spatial self‐organization can yield multiple CLSs, with larger length scales indicating the emergent dynamics of interactions between patches. While the prediction r2 metric of Pascual and Levin is suitable to estimate CLSs of complex systems, their method is not suitable to apply to most real ecosystems because of the requirement of long time series for attractor reconstruction. We offer two alternatives, both based on prediction r2, but where repetition in space is largely (the “short time series” method) or wholly (the “sliding window” method) substituted for repetition in time in attractor reconstruction. Both methods, and in particular the short time series based on only three or four sequential observations of a system, are robust in detecting the primary length scale of complex systems. We conclude that the modified techniques are suitable for application to natural systems. Thus they offer, for the first time, an opportunity to estimate natural scales of real ecosystems, providing objectivity in important decisions about scaling in ecology.
INVERTEBRATE BIODIVERSITY IN AGRICULTURAL AND URBAN HEADWATER STREAMS: IMPLICATIONS FOR CONSERVATION AND MANAGEMENT
Authors: Moore Aaron A. , Palmer Margaret A.
Published: June 2007

The urbanization of agricultural lands is currently one of the dominant patterns of land use change in developed countries. In the United States and parts of Europe, this has led to the implementation of agricultural land preservation programs and riparian protection and replanting efforts along urban streams. The ecological benefits of such programs for the conservation of freshwater biodiversity have yet to be fully explored. We designed a study to investigate the patterns of stream macroinvertebrate community structure along a gradient of agriculture to urban development, and the patterns among urban streams that vary in the amount of intact riparian buffer. In 2001 and 2002, we sampled the 29 small headwater streams comprising the outlying tributaries of four watersheds just north of Washington, D.C., in Montgomery County, Maryland, USA. This region has had dramatic urban development over the last 50 years, yet significant efforts have been made to maintain riparian buffers and promote preservation of agricultural land.

Macroinvertebrate richness was strongly related to land use, with agricultural streams exhibiting the highest macroinvertebrate diversity. Taxa richness was related negatively and linearly (no statistical threshold) to the amount of impervious surface cover. For the urban streams, there was a strong positive relationship between invertebrate diversity and riparian forest cover. Urban streams with high amounts of intact riparian forest exhibited biodiversity levels more comparable to less urban areas despite high amounts of impervious cover in their catchments. The agricultural headwater streams in this study were not only more diverse than the urban headwaters, but their levels of macroinvertebrate diversity were high compared to other published estimates for agricultural streams. These higher richness values may be due to widespread use of “best management practices” (BMPs), including no‐till farming and the implementation of woody and herbaceous riparian buffers, which may alleviate many acute stressors caused by cultivation. These findings suggest that, if managed properly, the preservation of agricultural land from development may help conserve stream invertebrate biodiversity, and that maintenance of riparian forests even in highly urbanized watersheds may help alleviate ecological disturbances that might otherwise limit macroinvertebrate survival.
WHY SHORT‐TERM EXPERIMENTS MAY NOT ALLOW LONG‐TERM PREDICTIONS ABOUT INTRAGUILD PREDATION
Authors: Briggs Cheryl J. , Borer Elizabeth T.
Published: June 2007

Equilibrium models are increasingly employed in applied ecology, but often because of experimental logistics, only short‐term laboratory experiments are performed. Here, we use simple models to examine the management relevance of this disconnection between theory and experiments in communities with intraguild predation (IGP). Equilibrium theory shows that IGP can promote coexistence of competitors on a shared resource. However, adding the intraguild predator can result in higher resource densities than in a system with the intraguild prey alone with its resource. This has important management implications when the shared resource is a pest species whose population is controlled by natural enemies. Our models demonstrate why short‐term experiments and studies ignoring alternate resources may bear no relationship to a system at equilibrium. Short‐term experiments quantifying only attack rates can predict a broad range of outcomes. By ignoring conversion efficiency, consumer longevity, and immigration, short‐term studies may, for example, cause erroneous decisions about the introduction of natural enemies in biological control. Thus, attack rates, conversion efficiencies, and immigration rates must all be quantified for a thorough, long‐term understanding of IGP in field systems.
GAUSSIAN ERROR PROPAGATION APPLIED TO ECOLOGICAL DATA: POST‐ICE‐STORM‐DOWNED WOODY BIOMASS
Authors: Lo Ernest
Published: June 2007

Error analysis using Gaussian error propagation (GEP) can be used to analytically determine the error or uncertainty produced by multiple and interacting measurements or variables. The technique is especially useful for studies that involve step‐by‐step calculations, where measurements taken at a smaller temporal or spatial scale are used to estimate a value at larger scales (e.g., daily total tree‐crown carbon assimilation is estimated from carbon assimilation rate per unit leaf area per unit time).

The GEP technique is not well known and rarely used in ecology. The purpose of this paper is to illustrate the concepts and methods of GEP in a manner that is accessible and relevant to students and researchers in ecology. The technique is also extended to calculate the “error budget” and “sensitivity indices” of error sources. The concept of the “error structure” of an experiment or calculation is introduced, and different partitioning methods and optimization strategies for analyzing and reducing error, which further develop the potential usefulness of GEP, are shown. An example of its application to ecological data is demonstrated using the post‐ice‐storm‐downed woody‐biomass data set, previously reported by M. C. Hooper, K. Arii, and M. J. Lechowicz. Both the data and the error analysis can be viewed as being representative of and relevant to a general class of step‐by‐step and scaling‐up ecological calculations. Finally the use of GEP reveals that the error structure is a scale‐dependent quantity, a result that is relevant to both scaling theory and experimental design.
POPULATION PERSISTENCE OF CALIFORNIA CURRENT FISHES AND BENTHIC CRUSTACEANS: A MARINE DRIFT PARADOX
Authors: Shanks Alan L. , Eckert Ginny L.
Published: June 2007

Because flow in the California Current is unidirectional for months, larvae of coastal species may drift and settle downstream of their parents, potentially causing the parental population to go extinct from upstream to downstream; this is a marine equivalent of the drift paradox in streams. Unidirectional larval drift might, however, be minimized by when, where, and how organisms reproduce. We compiled data on California Current fishes (89 nearshore, 65 shelf/slope) and benthic crustaceans (35 nearshore, 15 shelf/slope) and found three unique sets of life history traits displayed by (1) shelf/slope species, (2) nearshore pelagic‐spawning fishes (all from the Southern California Bight [SCB] and Baja California), and (3) all other nearshore species. Pelagic larval durations (PD) of shelf/slope species are long (∼136 d); offspring are pelagic winter through summer and are found at depth below the mixed layer offshore. Offspring experience northward flow in winter and southward flow in spring/summer, perhaps minimizing net alongshore drift. Adults are both long‐lived and highly fecund. Nearshore species have short PDs (∼45 d), and offspring are pelagic during spring/summer upwelling and are found nearshore and near the bottom. Nearshore larvae may experience southward flow during upwelling and northward flow during relaxation events, minimizing net alongshore transport. Nearshore species have shorter lives and are less fecund than shelf/slope species. Nearshore pelagic‐spawning fishes (all from the SCB and Baja) have short PDs (∼48 d), but in contrast to other nearshore species, their larvae are pelagic from spring into fall and are found far from shore. Adults are long‐lived, highly fecund, and have numerous broods per year. These life history traits may have evolved to exploit eddies and countercurrents present in the SCB and off Baja for larval retention. Each set of life history traits appears to improve chances of offspring recruiting to parental populations. The pelagic phase, rather than being dispersive, may be selected to achieve a migration between larval pelagic and adult benthic habitats.
MULTISCALE CONTROLS ON WOODY PLANT DIVERSITY IN WESTERN OREGON RIPARIAN FORESTS
Authors: Sarr Daniel A. , Hibbs David E.
Published: June 2007

Riparian forests are known to be floristically diverse and influenced by multiscale phenomena, yet few studies have explicitly compared how these factors contribute to various aspects of riparian plant diversity. We analyzed woody riparian plant species and environmental data from four western Oregon watersheds distributed across a wide climate‐driven productivity gradient at three scales (40‐m2 sample plots [alpha diversity], 1‐ha plots, and species pools from 16 1‐ha plots in each watershed) to compare three hypotheses of control on species diversity: (1) local control, (2) direct climatic control, and (3) indirect climatic control. We used a process model (3‐PG) to model gross primary productivity (GPP) as a functional climate index across our study area. We performed multiple linear regression to determine the best predictors of alpha (sample‐plot scale) diversity, compositional change within riparian forests (beta diversity), and hectare‐scale diversity and used path analysis to explore hypothesized causal linkages between climate and other factors and species diversity. We also analyzed a companion data set of gap and forest environments from a subset of the same sites to determine the influence of disturbance on species diversity across the gradient.

We found evidence for strong spatial patterning in woody plant richness consistent with indirect climatic control on woody plant richness. Climate (GPP) showed negative relationships with alpha diversity and hectare richness of trees, shrubs, and woody plant species and was the most commonly selected explanatory variable in regression analyses. GPP and Rubus spectabilis cover increased from the least to most productive climates while understory light and moisture heterogeneity across the riparian area decreased. These environmental changes coincided with declines in alpha, beta, and hectare‐scale diversity. Disturbance gaps yielded higher richness at most sites, but differences in species richness between gap and forest sample plots did not increase at high levels of GPP, as hypothesized.

This study points toward an integrated conceptual model whereby regional and landscape scale controls such as climate and watershed position complement and interact with local controls (i.e., vegetation structure, environmental gradients) to jointly govern woody plant diversity in riparian forests.
TUNDRA CO2 FLUXES IN RESPONSE TO EXPERIMENTAL WARMING ACROSS LATITUDINAL AND MOISTURE GRADIENTS
Authors: Oberbauer Steven F. , Tweedie Craig E. , Welker Jeff M. , Fahnestock Jace T. , Henry Greg H. R. , Webber Patrick J. , Hollister Robert D. , Walker Marilyn D. , Kuchy Andrea , Elmore Elizabeth , Starr Gregory
Published: June 2007

Climate warming is expected to differentially affect CO2 exchange of the diverse ecosystems in the Arctic. Quantifying responses of CO2 exchange to warming in these ecosystems will require coordinated experimentation using standard temperature manipulations and measurements. Here, we used the International Tundra Experiment (ITEX) standard warming treatment to determine CO2 flux responses to growing‐season warming for ecosystems spanning natural temperature and moisture ranges across the Arctic biome. We used the four North American Arctic ITEX sites (Toolik Lake, Atqasuk, and Barrow [USA] and Alexandra Fiord [Canada]) that span 10° of latitude. At each site, we investigated the CO2 responses to warming in both dry and wet or moist ecosystems. Net ecosystem CO2 exchange (NEE), ecosystem respiration (ER), and gross ecosystem photosynthesis (GEP) were assessed using chamber techniques conducted over 24‐h periods sampled regularly throughout the summers of two years at all sites.

At Toolik Lake, warming increased net CO2 losses in both moist and dry ecosystems. In contrast, at Atqasuk and Barrow, warming increased net CO2 uptake in wet ecosystems but increased losses from dry ecosystems. At Alexandra Fiord, warming improved net carbon uptake in the moist ecosystem in both years, but in the wet and dry ecosystems uptake increased in one year and decreased the other. Warming generally increased ER, with the largest increases in dry ecosystems. In wet ecosystems, high soil moisture limited increases in respiration relative to increases in photosynthesis. Warming generally increased GEP, with the notable exception of the Toolik Lake moist ecosystem, where warming unexpectedly decreased GEP >25%. Overall, the respiration response determined the effect of warming on ecosystem CO2 balance. Our results provide the first multiple‐site comparison of arctic tundra CO2 flux responses to standard warming treatments across a large climate gradient. These results indicate that (1) dry tundra may be initially the most responsive ecosystems to climate warming by virtue of strong increases in ER, (2) moist and wet tundra responses are dampened by higher water tables and soil water contents, and (3) both GEP and ER are responsive to climate warming, but the magnitudes and directions are ecosystem‐dependent.
EXPLOITING TEMPORAL VARIABILITY TO UNDERSTAND TREE RECRUITMENT RESPONSE TO CLIMATE CHANGE
Authors: Ibáñez Inés , Clark James S. , LaDeau Shannon , Lambers Janneke Hille Ris
Published: June 2007

Predicting vegetation shifts under climate change is a challenging endeavor, given the complex interactions between biotic and abiotic variables that influence demographic rates. To determine how current trends and variation in climate change affect seedling establishment, we analyzed demographic responses to spatiotemporal variation to temperature and soil moisture in the southern Appalachian Mountains. We monitored seedling establishment for 10 years in five plots located along an elevational gradient of five dominant tree species:Acer rubrum, Betulaspp.,Liriodendron tulipifera, Nyssa sylvatica,andQuercus rubra. A hierarchical Bayes model allowed us to incorporate different sources of information, observation errors, and the inherent variability of the establishment process. From our analysis, spring temperatures and heterogeneity in soil moisture emerge as key drivers, and they act through nonlinear population demographic processes. We found that all species benefited from warmer springs, in particular the species found on dry slopes,N. sylvatica, and those dominant at higher elevations,Betulaspp. andQ. rubra. This last species also benefited from dry environments. Conversely,L. tulipifera, which is abundant on mesic sites, experienced highest establishment rates at high moisture. The mechanisms behind these results may differ among species. Higher temperatures are apparently more important for some, while dry conditions and reduced pathogenic attacks on their seeds and new seedlings have a large impact for others. Our results suggest that only communities found at higher elevations are in danger of regional extinction when their habitats disappear given the current climatic trends. We conclude that the recruitment dynamics of the communities where these species are dominant could be affected by minor changes in climate in ways that cannot be predicted using only climate envelopes, which use different variables and miss the nonlinearities.
Why Do Maize Hybrids Respond Differently to Variations in Plant Density?
Authors: Sarlangue Tomás , Andrade Fernando H. , Calviño Pablo A. , Purcell Larry C.
Published: June 2007

Maize (Zea mays L.) grain yield responds greatly to plant density (D). However, the hybrid–plant density interaction usually found is not well understood. The objective of this work was to analyze responses of different maize hybrids to D considering their biomass plasticity and reproductive partitioning. Responses to D were analyzed during 2 yr in three hybrids with contrasting maturity and plasticity. The relationships between aboveground biomass per plant at maturity (Bp) and D and between grain yield per plant (Yp) and Bp were used to explain hybrid responses to D Optimum D. ranged from 10.3 to 13.7 plants m−2. The hybrid with the lowest optimum D presented the greatest biomass plasticity and reproductive partitioning. Increasing D produced an increase in biomass production per unit area in all hybrids. Contrarily, a greater harvest index (HI) with increasing D was only observed in the hybrids with the least plasticity. Increments in grain yield with increasing D were, in all cases, more associated with increases in biomass production than with increments in HI. Parameters of the equations Bp − D and Yp − Bp were related to optimum D To validate these relationships, an independent data set was used. Some of these parameters were associated with biomass plasticity and reproductive partitioning and could be used to explain and estimate the responses to D
Deficit Irrigation for Optimum Alfalfa Seed Yield and Quality
Authors: Shock Clinton C. , Feibert Erik B. G. , Saunders Lamont D. , Klauzer Jim
Published: June 2007

While alfalfa (Medicago sativa L.) seed yield is known to respond positively to moderate deficit irrigation, the effects of deficit irrigation on seed viability and seed size are not known. Minimum seed viability for certification in Oregon is 85% germination plus hard seed. Two alfalfa cultivars (‘Tango’ and ‘Accord’) were planted in 2000 and were subjected to four subsurface drip irrigation treatments in 2001, 2002, and 2003 in eastern Oregon. Before flowering, the field was irrigated uniformly to replace approximately 65% of the accumulated alfalfa evapotranspiration (ETc). After the onset of flowering, four irrigation levels (80, 60, 40, and 20% of the accumulated ETc) were applied every 3 to 4 d to plots arranged in a randomized complete block design with five replicates. Seed yield showed a quadratic response to ETc replacement level and was maximized by an ETc replacement of 50% over the 3 yr. While germination decreased with increasing ETc replacement, hard and abnormal seed increased with increasing ETc replacement. The highest viable seed was achieved with an ETc replacement level of 32%, over the 3 yr. Seed weight increased with increasing ETc replacement level, but the largest increase occurred from 20 to 60% ETc replacement. With an ETc replacement of 50% that maximized yield, seed quality met or exceeded the minimum certification standard of 85% viable seed each year. The results suggest that alfalfa seed production can be optimized with 50% ETc replacement using drip irrigation.
Phosphorus Extraction by Cotton Fertilized with Broiler Litter
Authors: Tewolde H. , Sistani K. R. , Rowe D. E. , Adeli A.
Published: June 2007

Knowledge of the magnitude of P extracted and removed by harvested crop is an important component of effectively managing poultry litter to minimize or prevent the buildup of P in soil. This knowledge does not exist or is not well documented in cotton fertilized with litter as the primary fertilizer. The objective of this research was to quantify the magnitude of P extracted by cotton when fertilized with broiler litter and to determine whether supplementing litter with inorganic N improves P extraction. The research was conducted from 2002 to 2004 on two commercial farms representing a conventional‐till at Cruger and a no‐till at Coffeeville, MS, USA. At each location, the treatments consisted of an unfertilized control; a farm standard (STD) fertilized with inorganic fertilizers; and broiler litter of 2.2, 4.5, and 6.7 Mg ha−1 in an incomplete factorial combination with 0, 34, or 67 kg ha−1 N as urea ammonium nitrate (UAN) solution. The unfertilized control extracted an average across years of 27.7 kg P ha−1 at Cruger and 26.0 kg P ha−1 at Coffeeville. Application of both litter and UAN‐N decreased tissue P concentration but increased extracted amount of P because of increases in dry weight. The largest end‐of‐season P extraction in this research, which included 53.9 kg P ha−1 in 2004 at Cruger and 49.3 kg P ha−1 in 2002 at Coffeeville, was recorded for the treatment that received the largest litter rate of 6.7 Mg ha−1 supplemented with 34 or 67 kg ha−1 UAN‐N. Applied P always exceeded extracted P in all 3 yr at both locations when the litter rate was 4.5 or 6.7 Mg ha−1. Extracted P equaled or exceeded applied P when 2.2 Mg ha−1 litter was applied. Increasing litter rate decreased phosphorus extraction efficiency (PEE) while supplemental UAN‐N increased PEE. An average of 53% of the total P extracted was partitioned to seed with an additional 2.4% partitioned to lint for a total of 55% that would be removed with harvested crop. Nitrogen fertilization appeared to shift P partitioning from vegetative to reproductive parts. Supplementing litter with inorganic N may be an effective strategy not only in extracting additional P from soils but also in increasing the fraction partitioned to seed so that more P is removed from the field.
DUDE: A User‐Friendly Crop Information System
Authors: Yan Weikai , Tinker Nicholas A.
Published: June 2007

A crop information system facilitates the storage, retrieval, and utilization of historical crop performance data. Here, we report a user‐friendly crop information system entitled Data Unification and Distillation Engine (DUDE), which (i) converts data from spreadsheet formats to a relational database, (ii) allows editing of tables in the database, (iii) simplifies the construction and execution of queries from the database, (iv) formats queried data into a variety of file structures for data analyses, and (v) simplifies maintenance and corrections of data in the database. DUDE runs on any personal computer that operates with Windows 2000 or later versions of Microsoft Windows. DUDE is freely available from the authors.
Using Relative Chlorophyll Meter Values to Determine Nitrogen Application Rates for Corn
Authors: Hawkins J. A. , Sawyer J. E. , Barker D. W. , Lundvall J. P.
Published: June 2007

Determining specific N fertilization rates to achieve optimal return is difficult. Crop N stress sensing uses the plant as an indicator of N fertilization need and has potential to improve N management. However, for making N rate decisions, a calibrated relationship between measured N stress and optimum N rate is required. Corn (Zea mays L.) plant N stress was determined with a chlorophyll meter (CM) at 102 site‐years of N rate trials conducted from 1999–2005 with corn following soybean [Glycine max (L.) Merr.] (SC) and continuous corn (CC). Normalizing CM readings to relative chlorophyll meter (RCM) values reduced variation and improved the calibration of N stress with the nitrogen rate difference (ND) from the economic optimum nitrogen rate (EONR). With SC the adjusted R2 (adjR2) was 0.53 for CM readings and 0.73 for RCM values, and with CC the adjR2 was 0.57 for CM readings and 0.76 for RCM values. The same statistically significant (P < 0.001) relationship between RCM values and ND was found for both SC and CC, indicating RCM critical values of 0.97 and 0.98, respectively. This indicates the same calibration for N rate determination based on RCM values can be used for both rotations. Evaluation of RCM values at multiple corn growth stages indicated the same relationship to ND at the fifteenth leaf and silking growth stages, suggesting a period of time during mid‐to‐late vegetative growth to collect CM readings, and make in‐season N rate decisions and applications. The calibration of RCM values to the rate differential from optimum N can be used by producers to determine in‐season N applications for corn across varying production conditions.
Tetrahydronaphthalene-1,4-dione and its Chromiumtricarbonyl Complex
Authors: García Álvaro Enríquez , Kündig E. Peter , Lomberget Thierry , Bragg Ryan , Poulard Cyril , Bernardinelli Gerald
Published: June 2007

The article gives a brief outline of the rediscovery of tetrahydronaphthalene-1,4-dione, a stable tautomer which has been known for over half a century but has not been applied in synthesis. Desymmetrization is readily achieved via enantioselective reduction. Synthetic potential
apart, the dione and its chromiumtricarbonyl complex are of theoretical interest. Thus, whereas dihydroxynaphthalene requires quite harsh conditions and leads to a 1:1 mixture of the two tautomers, the chromiumtricarbonyl complex of dihydroxynaphthalene tautomerizes under very mild conditions
to the tetrahydronaphthalene-1,4-dione complex. An earlier literature report showed that in trifluoroacetic acid, the dione tautomer is present exclusively. This has now been used to isolate multigram quantities of the compound.
Light-Induced Spin Crossover Probed by Ultrafast Optical and X-ray Spectroscopies
Authors: Gawelda Wojciech , Cannizzo Andrea , Pham Van-Thai , El Nahhas Amal , Milne Christopher J. , Van der Veen Renske , Bressler Christian , Chergui Majed
Published: June 2007

The photoinduced energy and structural relaxation of aqueous iron(II)-tris-bipyridine ([FeII(bpy)3]2+), upon excitation into its singlet metal-to-ligand charge transfer (1MLCT) band, and the population of its short-lived (?0.6 ns) high-spin
excited state have been characterized by combined ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence up-conversion reveals a very short lived 1MLCT emission band, which decays in ?20 fs by intersystem crossing to a 3MLCT, whose very
weak emission is also observed. Transient absorption studies show that the latter decays in
Syntheses of Fluorescent Vitamin B12-Pt(II) Conjugates and their Pt(II) Release in a Spectroelectrochemical Assay
Authors: Ruiz-Sánchez Pilar , Mundwiler Stefan , Alberto Roger
Published: June 2007

The cisplatin adduct of vitamin B12, cis-[PtCl(NH3)2B12]+ (1) reacts with dansyl-imidazole to form cis-[Pt(dansyl-imidazole)(NH3)2B12] (2). In a spectroelectrochemical
assay, Co(III) in 2 was reduced to Co(II) under concomitant release of the Pt(II) complex. Since similar reduction occurs in the intracellular space, 2 can be used for studying cell uptake monitored by fluorescent microscopy. The insertion of a fluorescent marker into the platinum
moiety will also facilitate the isolation of the platinum complex released from B12 and therefore to characterize its chemical authenticity.
New Scholarship on the Holocaust
Authors: Langenbacher Eric
Published: June 2007

Over the six decades since the demise of the Nazi regime, thousands of pages have been written about the genocide of European Jews in almost every genre and intellectual forum. Eva Hoffman even concludes that "the Holocaust is the most documented event in history" (192). Nevertheless, the magnitude and complexity of the trauma and its aftereffects—on survivors, their descendents and the political cultures of many countries—left numerous lacunae and taboos that surrounded discourse and scholarship. Only relatively recently have more unconstrained questions been possible and various silences exposed. The three books examined in this review essay all contribute to the ongoing quest for comprehension, delving expertly into previously unexamined issues, while revealing how much still remains to work through the defining event of the 20th century.
The Ulenspiegel and anti-American Discourse in the American Sector of Berlin
Authors: Goldstein Cora Sol
Published: June 2007

In December 1945, less than six months after the unconditional defeat of the Third Reich and the military occupation of Germany, two anti-Nazi German intellectuals, Herbert Sandberg and Günther Weisenborn, launched the bimonthly journal, Ulenspiegel: Literatur, Kunst, und Satire (Ulenspiegel: Literature, Art and Satire), in the American sector of Berlin. Sandberg, the art editor, was a graphic artist. He was also a Communist who had spent ten years in Nazi concentration camps—the last seven in Buchenwald. Weisenborn, a Social Democrat and the literary editor, was a playwright, novelist, and literary critic. He had been a member of the rote Kapelle resistance group, was captured and imprisoned by the Gestapo in 1942, and was liberated by the Red Army in 1945.
Physical aggression as a function of perceived fighting ability and provocation: an experimental investigation
Authors: Archer John , Benson David
Published: June 2007

In three studies, Resource Holding Power (RHP) and provocation were manipulated in scenarios involving a young person in a bar with friends. In Study 1, teenage men reported lower likelihood of responding with physical aggression when insulted as levels of three RHP cues (size, allies and reputation) increased, effects that were accentuated by combinations of high‐RHP cues; in the second part of this study, they consistently rated an insult to their girlfriend as the most provoking from a range of possible provocations, chosen on theoretical and empirical grounds. Study 2 replicated the results of the first part of Study 1 in samples of men and women in their twenties, although the effects were weaker at low levels of RHP. Study 3 combined a high‐ or low‐provoking event, with low, medium or high RHP, and a wider range of response choices. As expected, direct aggression increased as provocation increased and RHP decreased. Delayed aggressive responses, including revenge fantasies, were highest in response to high provocation and high RHP. Findings are discussed in relation to theoretical models of aggressive motivation. Aggr. Behav. 34:9–24, 2008. © 2007 Wiley‐Liss, Inc.
Sliding mode control for an induction machine submitted to large variations of mechanical configuration
Authors: Betin Franck , Capolino Gérard‐André
Published: June 2007

In this paper, a variable structure control (VSC) algorithm with a time‐varying switching surface is combined with an indirect field‐oriented control in order to control the position of an induction machine shaft submitted to large variations of mechanical configuration such as inertia or load torque changes. The introduction of a time‐varying switching surface guarantees the existence of a sliding mode since the beginning of the shaft motion without any chattering effects. Indeed, this moving switching surface allows the reaching phase elimination and the motor behaviour is insensitive to unknown mechanical configuration changes. The algorithm has been first tested in simulation and then implemented using a low‐cost DSP platform combined with a numerical coprocessor. Finally, an advanced test bed is used in order to evaluate the tracking properties and the robustness capacities of the VSC law with variations of the mechanical configuration. Copyright © 2007 John Wiley & Sons, Ltd.
Nanostructured photoactive films synthesized by a flame aerosol reactor
Authors: Thimsen Elijah , Biswas Pratim
Published: June 2007

A flame aerosol reactor (FLAR) system was used to deposit nanostructured photocatalytic films of titanium dioxide with well controlled morphologies. Nanoparticles were generated in the aerosol phase and then deposited onto a water‐cooled substrate via thermophoresis. Two important parameters that influenced film characteristics were the titanium precursor feed rate and substrate temperature, through their effect on particle sintering dynamics on the substrate. The size of the particles as they arrived at the substrate was controlled by varying the titanium precursor feed rate. When the size was below ∼8 nm, sintering was completed in the time available to obtain films with columnar nanostructures. Larger particle sizes resulted in granular, particulate films. The temperature of the substrate was also an important parameter as it controlled the sintering rate and the resultant crystal phase of the film. The thickness of the films was controlled by varying the precursor feed rate and deposition time. The performance of the as‐synthesized photocatalytic films was established by measuring the resultant photocurrents. Well sintered columnar morphologies and thicker films (in the range of 40–900 nm) resulted in the largest photocurrents. © 2007 American Institute of Chemical Engineers AIChE J, 2007
Human skeletal remains from Sabana de Bogotá, Colombia: A case of Paleoamerican morphology late survival in South America?
Authors: Neves Walter A. , Hubbe Mark , Correal Gonzalo
Published: June 2007

Human skeletal remains of the first Americans are scarce, especially in North America. In South America the situation is less dramatic. Two important archaeological regions have generated important collections that allow the analysis of the cranial morphological variation of the Early Americans: Lagoa Santa, Brazil, and Sabana de Bogotá, Colombia. Human crania from the former region have been studied by one of us (WAN) and collaborators, showing that the cranial morphology of the first South Americans was very different from that prevailing today in East Asia and among Native Americans. These results have allowed for proposing that the New World may have been colonized by two different biological populations in the final Pleistocene/early Holocene. In this study, 74 human skulls dated between 11.0 and 3.0 kyr, recovered in seven different sites of Sabana de Bogotá, Colombia, were compared with the world cranial variation by different multivariate techniques: Principal Components Analysis, Multidimensional Scaling, and Cluster of Mahalanobis distance matrices. The Colombian skeletal remains were divided in two chronological subgroups: Paleocolombians (11.0–6.0 kyr) and Archaic Colombians (5.0–3.0 kyr). Both quantitative techniques generated convergent results: the Paleocolombians show remarkable similarities with Lagoa Santa and with modern Australo‐Melanesians. Archaic Colombians exhibited the same morphological patterns and associations. These findings support our long‐held proposition that the early American settlement may have involved two very distinct biological populations coming from Asia. On the other hand, they suggest the possibility of late survivals of the Paleoamerican pattern not restricted to isolated or marginal areas, as previously thought. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
Role of wild plant foods among late Holocene hunter‐gatherers from Central and North Patagonia (South America): An approach from dental evidence
Authors: Bernal Valeria , Novellino Paula , Gonzalez Paula N. , Perez S. Ivan
Published: June 2007

This study evaluates the role of plant foods in the subsistence of hunter‐gatherers that inhabited the Central East, Northwest, and Northeast Patagonia (Argentina) during the late Holocene (ca. 3,000–500 years BP). The goal of the present study is to assess the temporal variation of dental caries ratio and wear rate in skeletal samples to ascertain if the biological information supports the dietary shift toward greater consumption of wild plant foods around 1,500 years BP, suggested by other types of evidence. The authors registered caries, antemortem and postmortem tooth loss, and tooth wear from eight samples belonging to hunter‐gatherers from Patagonia for which chronological sequences from early late Holocene (ca. 3,000–1,500 years BP) up to final late Holocene (ca. 1,500–500 years BP) are available. The results indicate that caries percentages in Patagonian samples fall within the range established for hunter‐gatherers but there are significant geographical differences. In addition, caries ratio does not change significantly through time, so the amount of carbohydrates consumed seems to have remained fairly constant since 3,000 years BP. In contrast, there is a marked temporal trend toward the reduction of wear rates in the three areas, suggesting a faster rate in early late Holocene than in final late Holocene. These results would reflect a change to less hard and/or abrasive diets in the final late Holocene, probably owing to differences in food processing methods employed. Am J Phys Anthropol, 2007. © 2007 Wiley‐Liss, Inc.
The stochastic unit root model and fractional integration: An extension to the seasonal case
Authors: Caporale Guglielmo Maria , Gil‐Alana Luis A.
Published: June 2007

In a recent paper, Yoon (Working Paper, Department of Economics and Related Studies, University of York, 2003. Presented at the ESF‐EMM Second Annual Meeting, Rome, Italy, 2003) asserts that the stochastic unit root (STUR) model is closely related to long memory processes, and, in particular, that it is a special case of an I(d) process, with d = 1.5. In this paper we question this claim by using parametric and semiparametric techniques for modelling long memory. We extend the analysis by considering both non‐normality and seasonality, and shed light, theoretically and by means of Monte Carlo methods, on the relationship between the seasonal STUR and the seasonal I(d) models. The results show that methods that are specifically designed for testing I(d) statistical models are not appropriate for testing the STUR model. Moreover, they have in some cases very low power against STUR alternatives. Copyright © 2007 John Wiley & Sons, Ltd.
Analysis of peptide design in four‐, five‐, and six‐helix bundle template assembled synthetic protein molecules
Authors: Seo Emily S. , Sherman John C.
Published: June 2007

Four‐, five‐, and six‐helix bundle template assembled synthetic proteins (TASPs) have been synthesized using disulfide bonds between cavitand templates and peptides, and characterized in terms of stability and structural specificity. The peptide sequence (CGGGEELLKKLEE LLKKG) used was originally designed for a four‐helix bundle. The TASPs were analyzed using CD spectroscopy, chemical denaturation studies, NMR spectroscopy, sedimentation equilibria studies, and hydrophobic dye binding studies to determine the effect of a single peptide sequence when incorporated into bundles with different numbers of helices. If the design was indeed idealized for a four‐helix bundle, then the five‐ and six‐helix bundles should be less stable and manifest lower conformational specificity. The TASPs all demonstrated high stability and cooperative unfolding. However, the four‐helix bundle was found to be significantly more stable and nativelike compared to the five‐ and six‐helix bundles. This suggests that the peptide sequence is specific to the four‐helix bundle, as designed. This result demonstrates the ability to design de novo proteins with specified structure, not just generic stability. © 2007 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 88: 774–779, 2007.

This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Über die Synthese von Pyridazino Pyridazion [3.2‐b] chinazolonen‐(10)
Authors: Beyer Hans , Völcker Carlhyphen;Eduard
Published: June 2007

3‐Halogen‐pyridazine reagieren mit Anthranilsäure oder Anthranilsäure‐äthyl‐ester zu Pyridazino[3.2‐b ]chinazolonen‐(10), deren Eigenschaften beschrieben werden.
Zur Kenntnis der Chemie der Metallcarbonyle in flüssigem Ammoniak, XII. Die Reaktionen der Hexacarbonyle der Chromgruppe und ihrer Bipyridyl‐(2.2′)‐ und 1.10‐Phenanthrolin‐Substitutionsprodukte im Ammonosystem
Authors: Behrens Helmut , Harder Norbert
Published: June 2007

Die Hexacarbonyle M(CO)6 (M=Cr, Mo, W) setzen sich bei 120° mit flüssigem NH3 zu den Tricarbonyltriamminverbindungen M(CO)3(NH3)3 um; nur beim Cr(CO) 6 ist bei 80° auch Cr(CO)5NH3 zugänglich. Bei den Reaktionen von M(CO)4bipy und M(CO)4phen (bipy = Bipyridyl‐(2.2′), phen = 1.10‐Phenanthrolin) mit flüssigem NH3 erfolgt bei 120° Substitution einer CO‐Molekel unter Bildung der Verbindungstypen M(CO)3 bipyNH3 bzw. M(CO)3phenNH3. Bei den Umsetzungen von M(CO)4bipy mit Kaliumcyanid in flüssigem NH3 wird bei 60° bipy vollständig durch CN⊖ ersetzt. Hierbei werden mit Cr(CO)4bipy K2[Cr0(CO) 4(CN)2], mit Mo(CO)4bipy und W(CO)4bipy unter gleichzeitiger CO‐Substitution K3[M0(CO) 3(CN)3] gebildet.
Synthese substituierter Benzoesäuren, Benzonitrile und Benzaldehyde
Authors: Effenberger Franz , Gleiter Rolf
Published: June 2007

Substituierte Benzoesäuren, Benzonitrile und Benzaldehyde sind auf einfache Weise über die substituierten N‐Alkyl‐bzw. N‐Aryl‐benzoesäureamide zugänglich.
Arylsulfonylimine: Darstellung, Eigenschaften und Reaktivität
Authors: Albrecht Rudolf , Kresze Günter , Mlakar Bogdan
Published: June 2007

Zwei neue Wege zu N‐Arylsulfonyl‐iminen bzw. ‐formamidinen werden beschrieben.
Über die Umsetzung einiger α‐Aminoimidsäureester mit Hydrazin
Authors: Westermann Peter
Published: June 2007

Die Imidsäureester des N‐Tosyl‐ und N‐Cbo‐glycins sowie der von N‐Tosyl‐phenylaminoessigsäure geben mit äthanolischem Hydrazin substituierte Dihydro‐s‐tetrazine (Ia–c) und substituierte 1.2.4‐Triazole (IIa–c), die N‐Tosyl‐Verbindungen der α‐Amino‐ buttersäure und ‐isobuttersäure dagegen nur die Dihydrotetrazine Id und e.
Zur Epimerisierung von Galanthamin
Authors: Volpp Gert P. , Bubewa‐Iwanowa Lilia
Published: June 2007

Das kürzlich als 2‐Hydroxy‐4.5‐epoxy‐6‐O‐methyl‐tetrahydro‐apogalanthamin beschriebene Abbauprodukt aus Galanthamin wurde als (–)‐Epigalanthamin identifiziert.
Die Reaktion von Natrium‐bis‐trimethylsilyl‐amid mit Carbonylchloriden
Authors: Pump Joachim , Rochow Eugene G.
Published: June 2007

Natrium‐bis‐trimethylsilyl‐amid reagiert mit Carbonylchloriden unter Bildung der entsprechenden N‐Trimethylsilyl‐carbimidsäure‐trimethylsilylester: magnified image Darstellung und Eigenschaften einer Reihe von Verbindungen werden beschrieben und die Struktur auf Grund der in Abhängigkeit von der Temperatur auf‐genommenen NMR‐ und IR‐Spektren diskutiert.
Über β‐Amino‐propionamidine und einige andere Umwandlungsprodukte von β‐Acylamino‐propionitrilen
Authors: Hilgetag Günter , Paul Heinz , Günther Joachim , Witt Margarete
Published: June 2007

β‐Tosyl(Cbo)amino‐propionitrile lassen sich in Amide oder Thioamide sowie Imidsäureester überführen. Vom β‐[p‐Tosylamino]‐propionimidsäureester werden mit Ammoniak das Amidin, mit anderen Aminen entsprechend substituierte Amidine zugänglich. Nach Abspaltung der Schutzgruppe wird das β‐Amino‐propionamidin in Form von Salzen erhalten.
Alkali‐Phosphorverbindungen und ihr reaktives Verhalten, XXIV. P.P‐Cyclohexylsubstituierte Phosphide von Titan(II), Vanadin(III) und Chrom(III)
Authors: Issleib Kurt , Wenschuh Eberhard
Published: June 2007

LiPR2 (R = c‐C6H11) reagiert mit TiCl3 · 3 THF bzw. TiCl4 · 2 THF zu Ti(PR2)2 und R2P – PR2, mit VCl3 · 3 THF und CrCl3 · 3 THF zu V(PR2)3 bzw. Cr(PR2. Die Umsetzung von Ti(PR2)3 als Oxydationsprodukte; überschüssiges Jod spaltet die Metallphosphor‐Bindung unter Bildung von R2PJ bzw. R2PJ3 Aus Cr(PR2)3 und Eisessig entstehen Cr(Ch3CO2)2 und R2PH. Der Spaltungsverlauf mit Methyljodid erlaubt Rückschlüsse auf die Stabilität der Metall‐Phosphor‐Bindung.
Über Osonhydrazone, XIV. Darstellung von Osonhydrazon‐oximen
Authors: Henseke Günter , Pelz Hans‐Werner
Published: June 2007

Oson‐1‐hydrazone und Osazone, die nur asymmetrisch disubstituierte Hydrazinreste enthalten, reagieren mit Hydroxylamin unter Bildung von Oson‐1‐hydrazon‐2‐oximen. Mit primären Hydrazinen lassen sich daraus Mischosazone herstellen. Vergleichend wird über entsprechende Derivate des Methylglyoxals berichtet.
Über Bildungsweisen und Verhalten pentaarylierter Spiroarsene
Authors: Wittig Georg , Hellwinkel Dieter
Published: June 2007

Mit Hilfe der Tosylimin‐Methodik wurde eine Reihe Pentaarylarsene synthetisiert, von denen III, VI und X eingehender auf ihr Verhalten gegenüber elektrophilen Reagenzien und bei thermischen Abwandlungen untersucht wurden. Da sich das Aniliniumsalz XIX nicht in optische Antipoden zerlegen ließ, stellte man die Spiroarsoniumhalogenide XX, XXIII und XXIV her, von denen XXIV in einer rechts‐ und linksdrehenden Komponente gewonnen werden konnte. Beide lieferten mit Phenylithium das racemische Spiroarsen XXV.
Polyacetylenverbindungen, LII. Über den Mechanismus der oxydativen Dimerisierung von Acetylenverbindungen
Authors: Bohlmann Ferdinand , Schönowsky Hubert , Inhoffen Eberhard , Grau Gerhard
Published: June 2007

Der Mechanismus der oxydativen Dimerisierung von Acetylenverbindugen untersucht. Bei wachsender Zahl von konjugierten Dreifachbindungen werden die Reaktions‐geschwindigkeiten im alkalischen Bereich größer, im sauren Bereich aber kleiner. Diese überraschende Tatsache läßt sich jedoch befriedigend durch einen. Mechanismus deuten, der durch eine oxydative Cyclisierung sowie gemischte Dimerisierungen gestützt wird.
Die Umsetzung ungesättigter Kohlenwasserstoffe mit 2.4‐Dinitro‐benzoldiazoniumsalz, I
Authors: Marxmeier Harald , Pfeil Emanuel
Published: June 2007

Unter günstigen Reaktionsbedingungen wird eine größere Zahl von Derivaten des Äthylens bei der Einwirkung von 2.4‐ Dinotro‐benzoldiazoniumsalzen in Carbonylverbindung und Dinitrophenylhydrazon gespalten. Die Abhängigkeit der Reaktion von den Experimentellen Faktoren und der Struktur des Äthylens wird untersucht.
Säureamid‐Reaktionen, XXXIX. Synthese des Imidazols
Authors: Bredereck Hellmut , Gompper Rudolf , Bangert Rolf , Herlinger Heinz
Published: June 2007

Eine einfache Synthese des Imidazols aus Bromacetaldlehyd‐äthylenacetal und Formamid in Gegenwart von Ammoniak wird beschrieben.
Synthesen mit Kohlenmonoxyd, II. Lactone durch Hydroformylierung ungesättigter Carbonsäureester
Authors: Falbe Jürgen , Huppes Nicolaas , Korte Friedhelm
Published: June 2007

Aliphatische bzw. alicyclische α.β‐und β‐γ‐ungesättigte Carbonsäureester liefern in Gegenwart von Co2(CO)8 als Katalysator mit Synthesegas bei 200–250β gesättigte mono‐ bzw. bicyclische Lactone. Bei längerkettigen α.β‐ungesättigten Estern werden infolge Isomerisierung während der Reaktion neben γ‐ auch δ‐Lactone erhalten.