bluuebunny/crossref_metadata_2025 huggingface dataset:
Facing Off
Authors: Rittelmann Leesa
Published: December 2009

In 1926 Weimar photographer László Moholy-Nagy predicted that the illiteracy of the future would be ignorance not of reading or writing, but of photography. Five years later theorist Walter Benjamin described the ability to compare facial types via portrait photobooks as a vitally important skill. As Germany endured an interregnum identity crisis, the photographic book proved an effective alternative to what were perceived to be the more subjective, traditional “fine arts” of painting and sculpture. More than innocuous collections of fine art photography, these books functioned as physiognomic guidelines for the representation of national identity during Germany's turbulent transition from unstable democracy to totalitarian state. As conservative writer Ernst Jünger observed in 1934, portrait photobooks offered “a particularly effective means of tracking down the enemy's individual character,” because it is “easier to change one's views than one's face.” This essay charts portrait photography's exploitation as evidentiary support for nineteenth-century physiognomic theory and examines a resurgent interest in this outmoded “pseudoscience” in 1920s Germany. My analysis of the production and reception of two popular photobooks, one by Weimar photographer August Sander (The Face of Our Time), and the other by Nazi photographer Erna Lendvai-Dircksen (German Folk Faces), reveals the degree to which both progressive and reactionary factions relied on photography and physiognomy to help redefine a stable or “authentic” face of the nation in an otherwise unstable time. While Hitler's devotion to both photographic propaganda and biological determinism is well known, the fact that progressive Weimar photographers like Sander also believed in the medium's power to lay bare the nation's “true” character and corporeal countenance indicates a surprising cultural continuity between the two regimes downplayed by art history's focus on the Führer's repudiation of modern art. By exploring the way that two ideologically opposed photographers shared a reliance on physiognomic theory, this research demonstrates portrait photography's central importance within the discourse of modern German visual culture and challenges art history's persistent emphasis on aesthetic rupture, rather than cultural continuity, between Weimar and the Third Reich.
Unbowed and Unbroken
Authors: Conway Jack
Published: December 2009

This article is an interview with former Provisional Irish Republican Army active service volunteer and current Sinn Féin activist and visual artist Danny Devenny. Culled from interviews conducted in Belfast between 1998 and 2000, during the Northern Ireland peace process, Danny Devenny reflects on the role of visual arts in the republican movement and discusses how public images framed the IRA prison struggle, connected republican communities to their history and traditions, and helped lay the groundwork for the successful politicization of Sinn Féin.
Let Us Not Call Them Graphic Novels
Authors: Gordon Ian
Published: December 2009

This article examines some recent graphic novels and argues that they should be called comic books. Gordon evaluates the success of different artists at matching the style of art to the subject represented, discusses the representational and narrative possibilities of the comic form, and points to some flat moments in otherwise fine historical works.
Art on the Front Lines
Authors: Gosse Johanna
Published: December 2009

In November 2008, a symposium titled “On the Limits and Possibilities of Politics in Art” was held at the Pennsylvania Academy of Fine Arts (PAFA) in Philadelphia. The event was organized in conjunction with a retrospective exhibition for the American painter Peter Saul, who was one of seven noted artists invited to speak on the role of politics in their work. This essay uses the PAFA symposium as a point of entry into an exploration of the theoretical contradictions surrounding art's engagement with politics and offers a challenge to the notion of “political art” as a discrete category with definable “limits and possibilities.”
Metallo-supramolecular Systems for Synergistic Functions Based on Unique Arrangement of Ligation Sites
Authors: Nabeshima Tatsuya , Akine Shigehisa , Ikeda Chusaku , Yamamura Masaki
Published: December 2009

Pseudomacrocyclic compounds with 2,2′-bipyridine subunits and multimetal-assisting functional molecules with salamo and dipyrrin moieties as the N2O2 ligation moieties are described. The unique and suitable arrangement of these ligation units results in highly synergistic functions in the metallo-supramolecular systems.
Gold Nanoclusters as a Catalyst for Intramolecular Addition of Primary Amines to Unactivated Alkenes under Aerobic Conditions
Authors: Kitahara Hiroaki , Sakurai Hidehiro
Published: December 2009

Gold nanoclusters stabilized by the poly(N-vinyl-2-pyrrolidone) hydrophilic polymer (Au:PVP) catalyzed the intramolecular cycloaddition of primary amines to unactivated alkenes in the presence of formic acid derivatives. The reaction proceeded under neutral to slightly acidic conditions in air.
Complete Hydrodechlorination of DDT and Its Derivatives Using a Hydroxyapatite-supported Pd Nanoparticle Catalyst
Authors: Hashimoto Norifumi , Hara Takayoshi , Shimazu Shogo , Takahashi Yusuke , Mitsudome Takato , Mizugaki Tomoo , Jitsukawa Koichiro , Kaneda Kiyotomi
Published: December 2009

Complete hydrodechlorination of 1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane (DDT) and its derivatives 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (DDE) and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethane (DDD) was achieved using a hydroxyapatite-supported Pd nanoparticle catalyst (Pd0HAP) in the presence of molecular hydrogen under mild reaction conditions. The catalytic activity of Pd0HAP was significantly higher than those of previously reported Pd catalysts.
Budding and Fission of Cationic Binary Lipid Vesicles Induced by the Incorporation of Pyranine
Authors: Wang Zhonghua , Yasuhara Kazuma , Ito Hiroshi , Mukai Masaru , Kikuchi Jun-ichi
Published: December 2009

Pyranine, a multivalent anionic fluorescent dye, triggered the budding and production of small vesicles from giant vesicles that consisted of zwitterionic and cationic lipids. Calorimetric analysis and microscopic observations revealed that the binding of pyranine induced domain formations of the lipid bilayer followed by membrane fission.
Photoinduced Particle Size Change of Core–Shell Polymeric Micelle Containing Spirobenzopyran in Its Inner Core
Authors: Arisaka Yoshinori , Tamura Atsushi , Uchida Katsumi , Yajima Hirofumi
Published: December 2009

Amphiphilic diblock copolymers comprising poly(methyl methacrylate-co-spirobenzopyran methacrylate) and poly(ethylene glycol) were synthesized using atom transfer radical polymerization to develop a new photoresponsive drug carrier. The diblock copolymers formed core–shell polymeric micelles with photoresponsive inner cores. Spirobenzopyran in the core was isomerized to the merocyanine form by UV irradiation, which resulted in reduction of the micellar size without decrease in the association number. This inferred that the strongly intermolecular interactions between merocyanine residues caused the conformational change of the core segments, following reduction of the micellar size.
Effects of Removing Residual Chlorine on the Hydrogenation of Aromatic Hydrocarbons over Supported Ru Catalysts
Authors: Nakamura Takashi , Ohshima Masa-aki , Kurokawa Hideki , Miura Hiroshi
Published: December 2009

Hydrogenation activity of aromatic hydrocarbons was remarkably increased when the residual chlorine on Ru/Al2O3 and Ru/SiO2 was removed by washing. On the basis of FT-IR spectra in the CO region, a site active for hydrogenation reactions was created by removal of the residual chlorine.
Synthesis of Substituted Stilbenes via Direct Decarboxylative Coupling of Cinnamic Acids with Arylboronic Acids under Palladium Catalysis
Authors: Yamashita Mana , Hirano Koji , Satoh Tetsuya , Miura Masahiro
Published: December 2009

Readily available cinnamic acids possessing a hydroxy group including ferulic acid efficiently undergo direct decarboxylative arylation under palladium catalysis to form hydroxylated stilbenes. The reaction of related acids is also described.
Exploring the link between reading fiction and empathy: Ruling out individual differences and examining outcomes
Authors: Mar Raymond A. , Oatley Keith , Peterson Jordan B.
Published: December 2009

Readers of fiction tend to have better abilities of empathy and theory of mind (Mar et al., Journal of Personality 74: 1047–1078, 2006). We present a study designed to replicate this finding, rule out one possible explanation, and extend the assessment of social outcomes. In order to rule out the role of personality, we first identified Openness as the most consistent correlate. This trait was then statistically controlled for, along with two other important individual differences: the tendency to be drawn into stories and gender. Even after accounting for these variables, fiction exposure still predicted performance on an empathy task. Extending these results, we also found that exposure to fiction was positively correlated with social support. Exposure to nonfiction, in contrast, was associated with loneliness, and negatively related to social support.
Reality TV as a moral laboratory: A dramaturgical analysis of The Golden Cage
Authors: Krijnen Tonny , Tan Ed
Published: December 2009

Public debates on reality television often address the display of emotion and immoral conduct. Television scholars have recently proposed that while reality television offers its audience an opportunity to learn valuable lessons, they rarely address the issue of the morality of the genre. In this contribution, we analyze the display of emotion and immoral conduct in the Dutch reality show The Golden Cage. Reality television is viewed as constituting a ‘moral laboratory’. The question guiding our research revolved around the kind of exercise this moral laboratory provides for. A dramaturgical study of the display of actions and emotions as part of participant “projects” (Beckerman, Dynamics of drama: Theory and method of analysis, Drama Book Specialists, 1979) was used to answer this question. Results indicate that moral issues and emotions were continuously at stake, and immoral conduct appeared to be coupled with pleasurable emotions. It is concluded that the laboratory of The Golden Cage is at least equally suited for exercising autonomy and identity performance under competitive pressure as it is for the simulation of moral conflicts.
Density and habitat use at different spatial scales of a guanaco population (Lama guanicoe) in the Monte desert of Argentina
Authors: Acebes Pablo , Traba Juan , Malo Juan E. , Ovejero Ramiro , Borghi Carlos E.
Published: December 2009

The first density estimates of a peripheral guanaco population and its habitat use at different spatial scales are presented for a protected area of Monte desert, Argentina. Transects were surveyed in the wet and dry seasons of 2005. All guanaco herds observed during systematic surveys using roads and tracks were GPS located and their habitat use was identified. Herd size differed significantly between the dry and wet seasons. Population densities differed between wet (0.10–0.12 individuals/km2) and dry seasons (0.60–0.75 individuals/km2). The population estimates ranged from 75 individuals (dry season) to 388 individuals (wet season). Guanacos showed differential habitat use, the first determinant being abiotic factors, such as topography, soil characteristics or microclimate conditions, animals being detected in rougher rocky substrata in the dry season and in open flat terrain in the wet season, followed by a mesoscale selection defined by plant communities. At the latter scale, guanaco preferentially used mixed creosote bushland and saltbush more intensively during the wet season, and open scrub and columnar-cactus slopes in the dry season. The estimated population of this protected area was small but its population density was within the range of other populations and was relatively high for this dry and unproductive area.
The fruit bats (Chiroptera: Pteropodidae) of the Lesio-Louna Reserve, Bateke Plateau, Republic of Congo
Authors: King Tony , Dallimer Martin
Published: December 2009

We present the results of the first survey of the fruit bats of the Lesio-Louna Reserve in the Republic of Congo, an area representative of the larger Bateke Plateau region of the country. Mist-netting was conducted in 2002 during four seasonal sampling periods: late wet season, early dry season, late dry season and early wet season. Five species were recorded. Two were frequently trapped, Micropteropus pusillus (n=102 individuals) and Epomops franqueti (n=57). The remaining three were captured only occasionally, Myonycteris torquata (n=5), Hypsignathus monstrosus (n=2) and Megaloglossus woermanni (n=2). In agreement with studies of other fauna, our results confirm that the Bateke Plateau supports species associated with both forest and savanna habitats. However, species typical of forested habitats were also netted in forest edge and neighbouring savanna, suggesting that these species utilise surrounding habitat within the forest-savanna mosaic characteristic of the study area. We found statistically significant seasonal variation in juvenile body mass and forearm length in E. franqueti and in adult female nipple length in M. pusillus, suggesting breeding seasonality in both these species in the reserve.
Transcutaneous Bilirubin Levels for the First 120 Postnatal Hours in Healthy Neonates
Authors: Fouzas Sotirios , Mantagou Lito , Skylogianni Eleni , Mantagos Stefanos , Varvarigou Anastasia
Published: December 2009

OBJECTIVE: The objective of this study was to provide data on transcutaneous bilirubin (TcB) levels for the first 120 postnatal hours and to develop an hour-specific TcB nomogram for healthy term and near-term neonates.

METHODS: From September 2005 to August 2008, we obtained 14864 TcB measurements from 2818 healthy neonates (gestational age ≥ 35 weeks and birth weight ≥ 2000 g). All measurements were performed with the BiliCheck bilirubinometer, at designated times from 12 to 120 postnatal hours. TcB percentiles for each designated time were calculated and used for the development of an hour-specific nomogram. TcB percentiles for neonates who required phototherapy are also presented.

RESULTS: The developed TcB nomogram reflects the natural history of TcB levels in healthy neonates up to the fifth postnatal day. A different pattern of TcB increasing rate was noted in neonates who did and did not require phototherapy but with substantial overlap of TcB values between the 2 groups.

CONCLUSIONS: We provide data on TcB levels for the first 120 postnatal hours from a large population of white, healthy, term and near-term neonates. We also present a percentile-based TcB nomogram designated for noninvasive and hour-specific evaluation of neonatal hyperbilirubinemia.
Slower Reaction Times and Impaired Learning in Young Adults With Birth Weight <1500 g
Authors: Strang-Karlsson Sonja , Andersson Sture , Paile-Hyvärinen Maria , Darby David , Hovi Petteri , Räikkönen Katri , Pesonen Anu-Katriina , Heinonen Kati , Järvenpää Anna-Liisa , Eriksson Johan G. , MD Eero Kajantie
Published: December 2009

OBJECTIVE: Children with very low birth weight (VLBW; <1500 g) perform worse on cognitive tests than do children who are born at term. Whether this difference persists into adulthood has been little studied. We assessed core neurocognitive abilities (processing speed, working memory, attention, and learning capacity) in young adults with VLBW and in term-born control subjects.

METHODS: In conjunction with the Helsinki Study of Very Low Birth Weight Adults, 147 VLBW and 171 control subjects who were aged 18 to 27 years and did not have neurosensory impairments performed a computerized test battery (CogState Ltd, Melbourne, Australia). T tests and linear regression models were used. Cohen's d was used to express effect size (ES).

RESULTS: VLBW adults had slower reaction times than did control subjects on all 5 tasks: simple reaction time (mean difference: 4.0% [95% confidence interval (CI): 1.1%–7.0%]; ES: 0.30), choice reaction time (mean difference: 3.2% [95% CI: 0.3%–6.2%]; ES: 0.24), working memory (mean difference: 8.4% [95% CI: 3.7%–13.4%]; ES: 0.40), divided attention (mean difference: 7.2% [95% CI: 2.7%–11.9%]; ES: 0.36), and associated learning reaction time (mean difference: 6.4% [95% CI: 1.3%–11.9%]; ES: 0.28). In addition, VLBW adults showed impaired learning abilities on the associated learning task (percentage of correct responses: 85.7 vs 80.2; P < .001; ES: 0.64). The results were little affected by adjustment for confounders.

CONCLUSIONS: Nonimpaired VLBW individuals exhibited slower psychomotor speed and lower accuracy on the associated learning task. These results indicate that very preterm birth, even when obvious neurosensory deficits are absent, may have long-term consequences on core neurocognitive abilities.
Quantitative Polymerase Chain Reaction (PCR) Assays for a Bacterial Thiaminase I Gene and the Thiaminase-Producing Bacterium Paenibacillus thiaminolyticus
Authors: Richter Catherine A. , Wright-Osment Maureen K. , Zajicek James L. , Honeyfield Dale C. , Tillitt Donald E.
Published: December 2009

The thiaminase I enzyme produced by the gram-positive bacterium Paenibacillus thiaminolyticus isolated from the viscera of Lake Michigan alewives Alosa pseudoharengus is currently the only defined source of the thiaminase activity linked to thiamine (vitamin B1) deficiency in early mortality syndrome (EMS) in the larvae of Great Lakes salmonines. Diets of alewife or isolated strains of P. thiaminolyticus mixed in a semipurified diet and fed to lake trout Salvelinus namaycush have been shown to produce EMS in fry. We utilized quantitative polymerase chain reaction (Q-PCR) to aid in studies of the sources of P. thiaminolyticus and thiaminase I. Quantitative PCR assays were established to detect the thiaminase I gene of P. thiaminolyticus, the 16S rRNA gene from most species of bacteria, and the 16S rRNA gene specifically from P. thiaminolyticus and a few closely related taxa. The Q-PCR assays are linear over at least six orders of magnitude and can detect the thiaminase I gene of P. thiaminolyticus from as few as 1,000 P. thiaminolyticus cells/g of sample or the Paenibacillus 16S rRNA gene from as few as 100 P. thiaminolyticus cells/g of sample. The initial results from alewife viscera samples with high thiaminase activity yielded unexpectedly low densities of P. thiaminolyticus cells; Paenibacillus thiaminolyticus was detectable in 2 of 6 alewife viscera tested at densities on the order of 100 cells/g out of 100,000,000 total bacterial cells/g. The low numbers of P. thiaminolyticus detected suggest that alewives contain additional non–P. thiaminolyticus sources of thiaminase activity.
Linking Egg Thiamine and Fatty Acid Concentrations of Lake Michigan Lake Trout with Early Life Stage Mortality
Authors: Czesny Sergiusz , Dettmers John M. , Rinchard Jacques , Dabrowski Konrad
Published: December 2009

The natural reproduction of lake trout Salvelinus namaycush in Lake Michigan is thought to be compromised by nutritional deficiency associated with inadequate levels of thiamine (vitamin B1) in their eggs. However, mortality driven by thiamine deficiency (commonly referred to as early mortality syndrome (EMS)) is not the only significant cause of low lake trout survival at early life stages. In this study, we sought to better understand the combined effects of variable levels of thiamine and fatty acids in lake trout eggs on prehatch, posthatch, and swim-up-stage mortality. We sampled the eggs of 29 lake trout females from southwestern Lake Michigan. The concentrations of free thiamine and its vitamers (e.g., thiamine monophosphate (TMP) and thiamine pyrophosphate (TPP)) as well as fatty acid profiles were determined in sampled eggs. Fertilized eggs and embryos were monitored through the advanced swim-up stage (1,000 degree-days). Three distinct periods of mortality were identified: prehatch (0–400 degree-days), immediately posthatch (401–600 degree-days), and swim-up (601–1,000 degree-days). Stepwise multiple regression analysis revealed (1) that cis-7-hexadecenoic acid in both neutral lipids (NL) and phospholipids (PL) correlated with prehatch mortality, (2) that docosapentaenoic acid in PL and docosahexaenoic acid in NL correlated with posthatch mortality, and (3) that total lipids, TPP, and palmitoleic acid in NL, linoleic acid, and palmitic acid in PL correlated with the frequency of EMS. These results indicate the complexity of early life stage mortality in lake trout and suggest that inadequate levels of key fatty acids in eggs, along with variable thiamine content, contribute to the low survival of lake trout progeny in Lake Michigan.
Gizzard Shad Thiaminase Activity and Its Effect on the Thiamine Status of Captive American Alligators Alligator mississippiensis
Authors: Ross J. Perran , Honeyfield Dale C. , Brown Scott B. , Brown Lisa R. , Waddle Amanda Rice , Welker Michael E. , Schoeb Trenton R.
Published: December 2009

Adult mortality and low egg hatch rate were observed among American alligators Alligator mississippiensis in Lake Griffin, Florida, between 1998 and 2003. Previous studies show that the alligator mortality is due to neurological impairment associated with thiamine (vitamin B1) deficiency. This study determined the rate of thiaminase activity in gizzard shad Dorosoma cepedianum, a fish often eaten by alligators, and examined the thiamine status of captive adult alligators fed only gizzard shad. We found that the thiaminase activity of gizzard shad in Lake Griffin is 16,409 ± 2,121 pmol/g/min (mean ± 2SEs). This high rate of thiaminase activity was present in most months and across a wide range of shad sizes. Seven alligators were captured in the wild from Lake Griffin and Lake Woodruff, held in captivity, and fed gizzard shad. We monitored blood and muscle thiamine levels throughout the experiment and liver thiamine at the end. Over a period of 6–12 months, all of the alligators maintained weight but blood and muscle thiamine levels decreased to 25–50% of the original (healthy) values. Three animals with the greatest reduction in thiamine died, demonstrating mobility impairment and neural histopathology similar to those seen in wild alligators in Lake Griffin. Two alligators were fed shad for 10 months but then treated with thiamine. These animals showed a reduction in thiamine while eating shad, but treatment restored their thiamine levels to the initial values, which were comparable to those of normal wild Lake Griffin alligators. We demonstrated that thiamine deficiency can be induced by a diet of gizzard shad and cause neurological signs and death in alligators in captivity. We conclude that the thiaminase activity in gizzard shad is high enough to cause thiamine deficiency in wild alligators when shad are a major part of their diet.
Egg Fatty Acid Composition from Lake Trout Fed Two Lake Michigan Prey Fish Species
Authors: Honeyfield Dale C. , Fitzsimons John D. , Tillitt Donald E. , Brown Scott B.
Published: December 2009

We previously demonstrated that there were significant differences in the egg thiamine content in lake trout Salvelinus namaycush fed two Lake Michigan prey fish (alewife Alosa pseudoharengus and bloater Coregonus hoyi). Lake trout fed alewives produced eggs low in thiamine, but it was unknown whether the consumption of alewives affected other nutritionally important components. In this study we investigated the fatty acid composition of lake trout eggs when females were fed diets that resulted in different egg thiamine concentrations. For 2 years, adult lake trout were fed diets consisting of four combinations of captured alewives and bloaters (100% alewives; 65% alewives, 35% bloaters; 35% alewives, 65% bloaters; and 100% bloaters). The alewife fatty acid profile had higher concentrations of arachidonic acid and total omega-6 fatty acids than the bloater profile. The concentrations of four fatty acids (cis-13, 16-docosadienoic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids) were higher in bloaters than in alewives. Although six fatty acid components were higher in lake trout eggs in 2001 than in 2000 and eight fatty acids were lower, diet had no effect on any fatty acid concentration measured in lake trout eggs in this study. Based on these results, it appears that egg fatty acid concentrations differ between years but that the egg fatty acid profile does not reflect the alewife–bloater mix in the diet of adults. The essential fatty acid content of lake trout eggs from females fed alewives and bloaters appears to be physiologically regulated and adequate to meet the requirements of developing embryos.
Weed Seed Contamination of Cotton Gin Trash
Authors: Norsworthy Jason K. , Smith Kenneth L. , Steckel Lawrence E. , Koger Clifford H.
Published: December 2009

Cotton gins in Arkansas, western Tennessee, and western Mississippi were sampled for weed seed contamination of gin trash in fall 2007. A total of 473 samples were collected, with 453 samples from Arkansas. The objectives of this research were to determine the weed species most frequently found in gin trash and determine what means gin operators are using to dispose of gin trash. There were 25 weed species found in the gin trash samples—11 grass and 14 broadleaf weeds. Grass and broadleaf weeds were present in 41.4 and 8.5% of the samples, respectively. The most frequently found species were large crabgrass (19.0%), barnyardgrass (14.0%), goosegrass (12.9%), red sprangletop (8.2%) and Palmer amaranth (4.2%). Viable seeds of barnyardgrass, large crabgrass, Palmer amaranth, and prickly sida were present in the surface layer (0- to 25-cm depth) of gin trash piles after 1 yr of composting. Viable Palmer amaranth seeds were present in the surface layer of gin trash piles after 2 yr of composting, but no germinable seeds were found deeper than 25 cm following 1 yr of composting. Gin trash disposal involved application of the material to crop fields during the fall or winter months; composting followed by application of the compost as mulch or a soil amendment to gardens, flower beds, or crop fields; use as cattle feed; and coverage for landfills to reduce erosion and encourage growth of vegetation. Because of the demonstrated potential for weed seed dispersal via gin trash, including composted material, development of technologies to ensure disposal of a gin-trash product free of viable weed seed are justified.
Rapoport's rule, species tolerances, and the latitudinal diversity gradient: geometric considerations
Authors: Šizling Arnošt L. , Storch David , Keil Petr
Published: December 2009

The most pervasive species‐richness pattern, the latitudinal gradient of diversity, has been related to Rapoport's rule, i.e., decreasing latitudinal extent of species' ranges toward the equator. According to this theory, species can have narrower tolerances in more stable climates, leading to smaller ranges and allowing coexistence of more species. We show, using a simple geometric model, that the postulated decrease of species' potential range sizes toward the tropics would itself lead to a latitudinal gradient opposite to that observed. In contrast, an increase in extent of potential ranges toward the tropics would lead to the observed diversity gradient. Moreover, in the presence of geographic barriers constraining actual species' ranges, Rapoport's rule emerges if the latitudinal trend in extents of potential ranges (as defined by climatic tolerance) is opposite to that postulated or if variability in potential range extents decreases toward the poles. A strong implicit latitudinal diversity gradient (i.e., higher concentration of midpoints of species' potential ranges in the tropics), however, produces both observed macroecological patterns without the contribution of any latitudinal trends in species climatic tolerances or in potential range sizes. Our model underscores the necessity of discriminating theoretical processes and principles from the patterns we observe, and it is well supported by data on global distribution of species' range sizes.
A new method to track seed dispersal and recruitment using 15N isotope enrichment
Authors: Carlo Tomás A. , Tewksbury Joshua J. , del Río Carlos Martínez
Published: December 2009

Seed dispersal has a powerful influence on population dynamics, genetic structuring, evolutionary rates, and community ecology. Yet, patterns of seed dispersal are difficult to measure due to methodological shortcomings in tracking dispersed seeds from sources of interest. Here we introduce a new method to track seed dispersal: stable isotope enrichment. It consists of leaf‐feeding plants with sprays of 15N‐urea during the flowering stage such that seeds developed after applications are isotopically enriched. We conducted a greenhouse experiment with Solanum americanum and two field experiments with wild Capsicum annuum in southern Arizona, USA, to field‐validate the method. First, we show that plants sprayed with 15N‐urea reliably produce isotopically enriched progeny, and that δ15N (i.e., the isotopic ratio) of seeds and seedlings is a linear function of the 15N‐urea concentration sprayed on mothers. We demonstrate that three urea dosages can be used to distinctly enrich plants and unambiguously differentiate their offspring after seeds are dispersed by birds. We found that, with high urea dosages, the resulting δ15N values in seedlings are 103–104 times higher than the δ15N values of normal plants. This feature allows tracking not only where seeds arrive, but in locations where seeds germinate and recruit, because δ15N enrichment is detectable in seedlings that have increased in mass by at least two orders of magnitude before fading to normal δ15N values. Last, we tested a mixing model to analyze seed samples in bulk. We used the δ15N values of batches (i.e., combined seedlings or seeds captured in seed traps) to estimate the number of enriched seeds coming from isotopically enriched plants in the field. We confirm that isotope enrichment, combined with batch‐sampling, is a cheap, reliable, and user‐friendly method for bulk‐processing seeds and is thus excellent for the detection of rare dispersal events. This method could further the study of dispersal biology, including the elusive, but critically important, estimation of long‐distance seed dispersal.
Food supply influences offspring provisioning but not density‐dependent fecundity in a marine fish
Authors: Samhouri Jameal Farouq
Published: December 2009

Replenishment of many marine populations occurs through the entry of juveniles to adult populations following a pelagic larval stage. Because mortality during the pelagic stage is thought to be high and density independent, larval abundance and traits of individual larvae should have strong effects on overall population dynamics in marine organisms. Surprisingly, few experiments have tested how localized interactions among breeding adults affect the quantity and phenotypic traits of larvae they produce. Here I experimentally test for the influence of food competition, mate limitation, and population density on somatic growth, fecundity, and offspring provisioning (larval length and energy reserves) in a planktivorous, territorial coral reef damselfish, Stegastes partitus. I manipulated food supply and adult S. partitus density on isolated patch reefs in the Bahamas and also made behavioral observations of S. partitus occurring on nearby natural reefs at a range of population densities. On the experimental reefs, females experienced density‐dependent growth and fecundity; male reproductive success was density dependent, but male growth was not. Density‐dependent growth and reproduction were not moderated by food supplementation, and density‐dependent reproduction was not influenced by mate availability. On natural reefs, the frequency of aggressive interactions, particularly involving females, increased with population density, implicating aggression‐related energetic costs as the source of both forms of density dependence in the experiments. Food supplementation increased female somatic growth and larval energy reserves, suggesting that females allocated surplus energy to future reproductive potential and enhanced offspring quality. Neither experimental treatment affected larval length. By altering patterns of reproduction, the interplay between spatial variation in food availability and population density may drive population dynamics in a broad range of benthic marine organisms.
A framework for assessing ecosystem dynamics in response to chronic resource alterations induced by global change
Authors: Smith Melinda D. , Knapp Alan K. , Collins Scott L.
Published: December 2009

In contrast to pulses in resource availability following disturbance events, many of the most pressing global changes, such as elevated atmospheric carbon dioxide concentrations and nitrogen deposition, lead to chronic and often cumulative alterations in available resources. Therefore, predicting ecological responses to these chronic resource alterations will require the modification of existing disturbance‐based frameworks. Here, we present a conceptual framework for assessing the nature and pace of ecological change under chronic resource alterations. The “hierarchical‐response framework” (HRF) links well‐documented, ecological mechanisms of change to provide a theoretical basis for testing hypotheses to explain the dynamics and differential sensitivity of ecosystems to chronic resource alterations. The HRF is based on a temporal hierarchy of mechanisms and responses beginning with individual (physiological/metabolic) responses, followed by species reordering within communities, and finally species loss and immigration. Each mechanism is hypothesized to differ in the magnitude and rate of its effects on ecosystem structure and function, with this variation depending on ecosystem attributes, such as longevity of dominant species, rates of biogeochemical cycling, levels of biodiversity, and trophic complexity. Overall, the HRF predicts nonlinear changes in ecosystem dynamics, with the expectation that interactions with natural disturbances and other global‐change drivers will further alter the nature and pace of change. The HRF is explicitly comparative to better understand differential sensitivities of ecosystems, and it can be used to guide the design of coordinated, cross‐site experiments to enable more robust forecasts of contemporary and future ecosystem dynamics.
Associations between species and groups of sites: indices and statistical inference
Authors: Cáceres Miquel De , Legendre Pierre
Published: December 2009

Ecologists often face the task of studying the association between single species and one or several groups of sites representing habitat types, community types, or other categories. Besides characterizing the ecological preference of the species, the strength of the association usually presents a lot of interest for conservation biology, landscape mapping and management, and natural reserve design, among other applications. The indices most frequently employed to assess these relationships are the phi coefficient of association and the indicator value index (IndVal). We compare these two approaches by putting them into a broader framework of related measures, which includes several new indices. We present permutation tests to assess the statistical significance of species–site group associations and bootstrap methods for obtaining confidence intervals. Correlation measures, such as the phi coefficient, are more context‐dependent than indicator values but allow focusing on the preference of the species. In contrast, the two components of an indicator value index directly assess the value of the species as a bioindicator because they can be interpreted as its positive predictive value and sensitivity. Ecologists should select the most appropriate index of association strength according to their objective and then compute confidence intervals to determine the precision of the estimate.
Linking populations to landscapes: richness scenarios resulting from changes in the dynamics of an ecosystem engineer
Authors: Wright Justin P.
Published: December 2009

Predicting the effects of the loss of individual species on diversity represents one of the primary challenges facing community ecology. One pathway by which organisms of one species affect the distribution of species is ecosystem engineering. Changes in the dynamics of ecosystem engineers that lead to changes in the distribution of the patches of altered habitat are likely to lead to changes in diversity. I link data on the distribution of plant species found in the riparian zone of the Adirondacks (New York, USA) in patches modified by beaver and in unmodified forest patches to a model connecting the dynamics of ecosystem engineers to the dynamics of the patches that they create. These analyses demonstrate that changes in key parameters of the model, such as decreases in beaver colonization rates and rate of patch abandonment, lead to changes in species richness of up to 45% at the landscape scale, and that these changes are likely to occur over long time scales. This general approach of linking the population dynamics or behavior of a single species to changes in species richness at the landscape scale provides a means for both testing the importance of ecosystem engineering in different systems and developing scenarios to predict how changes in the dynamics of a single species are likely to affect species richness.
Hierarchical movement decisions in predators: effects of foraging experience at more than one spatial and temporal scale
Authors: Amano Tatsuya , Katayama Naoki
Published: December 2009

Animal movements in heterogeneous environments play a crucial role in a variety of ecological processes. Although a hierarchical structure to the scale of movements has been observed in many animal species, few studies to date have revealed what causes such multi‐spatial scale movements within the framework of optimal theories. Using detailed information on movement paths and prey captures by Intermediate Egrets in rice fields, this study explored the effects of individual experience at multi‐temporal scales on subsequent movement parameters. The results supported three predictions based on optimal foraging theories: (1) movement distances at small and large spatial scales are determined by past foraging experiences over short (one minute) and long (seven to eight minutes) temporal scales, respectively; (2) responses to prey encounters vary between temporal scales, e.g., prey attacks in the previous one minute caused egrets to walk away (i.e., area‐avoided search), whereas those in the preceding eight minutes caused egrets to stay around (i.e., area‐restricted search); and (3) the probability of patch departure by flying increases with decreasing intake rates in the previous seven minutes, and the quitting intake rate is mostly lower than the long‐term average, not including travel time. These results suggest that egrets make different adaptive decisions at different spatial scales: in response to a clumped prey distribution at a large spatial scale, and to a dispersed distribution or behavioral depression of prey at a small spatial scale. This study showed that the framework of optimal foraging theories is useful for comprehensively explaining the different movement modes in animals. It should also be emphasized that considering both area‐avoided and restricted searches at multi‐temporal scales is important for understanding movement decisions, particularly in organisms searching for hierarchically distributed resources.
Intraspecific competition between co‐infecting parasite strains enhances host survival in African trypanosomes
Authors: Balmer Oliver , Stearns Stephen Curtis , Schötzau Andreas , Brun Reto
Published: December 2009

It is becoming increasingly clear that under natural conditions parasitic infections commonly consist of co‐infections with multiple conspecific strains. Multiple‐strain infections lead to intraspecific interactions and may have important ecological and evolutionary effects on both hosts and parasites. However, experimental evidence on intraspecific competition or facilitation in infections has been scarce because of the technical challenges of distinguishing and tracking individual co‐infecting strains. To overcome this limitation, we engineered transgenic strains of the protozoan parasiteTrypanosoma brucei, the causal agent of human African sleeping sickness. Different strains were transfected with fluorescence genes of different colors to make them visually distinguishable in order to investigate the effects of multiple‐strain infections on parasite population dynamics and host fitness. We infected mice either with each strain alone or with mixes of two strains. Our results show a strong mutual competitive suppression of co‐infectingT. bruceistrains very early in infection. This mutual suppression changes within‐host parasite dynamics and alleviates the effects of infection on the host. The strength of suppression depends on the density of the co‐infecting strain, and differences in life‐history traits between the strains determine the consequences of strain–strain competition for the host. Unexpectedly, co‐infection with a less virulent strain significantly enhances host survival (+15%). Analysis of the strain dynamics reveals that this is due to the suppression of the density of the more virulent strain (−33%), whose degree of impact ultimately determines the physical condition of the host. The competitive suppression is likely caused by allelopathic interference or by apparent competition mediated by strain‐specific immune responses. These findings highlight the importance of intraspecific variation for parasite−parasite and parasite−host interactions. To fully understand parasite and disease dynamics, the genetic diversity of infections must be taken into account. Through changes in parasite dynamics, intraspecific variation may further affect transmission dynamics and select for increased virulence of each strain. The precise mechanisms underlying mutual suppression are not yet understood but may be exploitable to fight this devastating parasite. Our results are therefore not only of basic ecological interest investigating an important form of intraspecific competition, but may also have applied relevance for public health.
Restoration of eroded surfaces in Serbian ski-areas
Authors: Ristic Ratko , Radic Boris , Vasiljevic Nevena
Published: December 2009

The environmental impacts in Serbian ski areas are very strong, leading to landscape degradation and functionality losses. Construction or improvement works cause serious destruction of topsoil and native vegetation. Some activities enhance erosion production and sediment yield: clear cuttings; trunk transport down the slope; road construction and large excavations. Also, lack of erosion control works in ski areas, especially between April and October, result in various forms of land degradation such as furrows, gullies, landslides, or debris from rock weathering. The consequences of mismanagement in ski areas are noticeable in downstream sections of river beds, causing floods and bed-load deposition. Planning and designing activities, with the application of technical and biotechnical erosion control structures, through the concept of restoration, are necessary measures in the protection of ski areas.
Characteristics of soil types on small river islands in the central Danube basin
Authors: Galic Zoran , Ivanisevic Petar , Pekec Sasa , Kebert Marko , Stojnic Srdjan
Published: December 2009

Determination of soil characteristics orginated on small river islands in the alluvial plane of the Danube river is done in this paper. High content of silt+clay fractions was found in all the profiles in the humus?accumulative horizon. Textural class in the surface horizons ranged from sand?clay to clay. Below this horizon sand layers of different depths have been found. By the depth of profiles fraction of fine sand was found most often. In these horizons the capacity for air was increased. Processes of oxidoreduction have been determined by the depth of the entire profile on all small river islands and referred to the high degree of moistening during the vegetation season. Chemical properties of soil, originated on small river islands were in accordance with the characteristics of fluvisol in the alluvial plain of the Danube river. Soils characterized by the dominant sedimentation process (continuous flooding), high accumulation of organic matter, which is characterized by high production potential of forest ecosystems.
Density and vulnerability of capercaillie (Tetrao urogallus) in the area of Vitoroga in the Republika Srpska
Authors: Zubic Goran
Published: December 2009

Capercaillie is a threatened species over the greater part of Europe. The main causes of its vulnerability are, inter alia, habitat changes and forest operations. The aim of this paper is to estimate the capercaillie population size in the south?eastern part of Mt. Vitorog, and to make a comparative analysis of forest state so as to assess the impact of forest operations on this micropopulation. Its spring density (0.7?1.3 birds per km2) is lower compared to other Eurasian habitats (1.0?3.0 birds per km2). This was significantly contributed by the habitat changes and by the frequent disturbances of birds caused by forest operations. The present state of forests in FMU 'Vitoroga' is characterized by canopy thinning, changed mixture proportion (percentage of spruce increased on the account of fir), decrease in wood volume and increase in the number of smaller?diameter trees. Our results show that forestry operations are not harmonised with the biological demands of the capercaillie.
Analysis of forest soil acidification processes in the area of NP 'Kopaonik'
Authors: Kadovic Ratko , Belanovic Snezana , Knezevic Milan , Belojica Jelena , Knezevic Jasmina
Published: December 2009

In the last two decades, S and N critical loads have been used as indicators of ecosystem sustainability to soil acidification. The effect of acidification on the soil in forest ecosystems and their further development was the subject of numerous studies, based on which several mathematical models were developed. This paper presents the results of the analysis of acidification processes in brown podzolic soil on granodiorites in the stands of spruce and spruce and fir in the area of NP 'Kopaonik'. Critical loads of sulphur and nitrogen in these soils are presented using VSD model.
Spatial distribution of spruce trees in the nature reserve 'Jankove bare' on mt. Kopaonik
Authors: Stajic Branko , Vuckovic Milivoj , Smiljanic Marko
Published: December 2009

The methodology and applicability of the study of spatial distribution of trees in Serbian forestry have been insufficiently reported and presented. This paper, based on mathematical?statistical principles, analyses the method of spatial distribution of spruce trees in the Nature Reserve 'Jankove Bare' in the National Park 'Kopaonik'. The following methods in the group of distance methods were applied: Kotar's method (1993), T2?method, and the index of distance dispersion (Johnson, Zimmer, 1985). The study results in a pure uneven-aged spruce stand based on all three methods showed that spruce trees are randomly distributed over the stand area. Therefore, environmental conditions in the study stand can be regarded as homogeneous and equally suitable for tree growth, and there are no significant interactions between the trees, which could cause a higher competition between the trees for nutrients, water, etc.