bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiplex obliterative vascular disease. Challenge in diagnostics and in treatment
Authors: Szomják Edit , Dér Henrietta , Kerekes György , Veres Katalin , Tóth Judit , Olvasztó Sándor , Herczku Csaba , Soltész Pál
Published: November 2008

A perifériás artériás érbetegség napjainkban is aluldiagnosztizált kórkép. Kialakulásában és progressziójában számos befolyásolható és nem befolyásolható rizikótényező bír szereppel. Mint rendszerbetegség részjelensége és indikátora is lehet fatális kimenetelű cardio- és cerebrovascularis eseményeknek.
Esetismertetés:
A betegség multilokularitását jól példázza a szerzők által ismertetett 73 éves férfi beteg esete, akinél egyidejű carotisérintettség és az alsó végtagok kritikus végtagischaemiáját okozó és aortobifemoralis bypassra szoruló eltérés mellett a szív vonatkozásában többszörös, mechanikai szövődménnyel társult infarktus, inoperábilis coronariastátus, valamint implantálható cardioverter defibrillátort igénylő kamrai ritmuszavar volt jelen.
Következtetések:
A perifériás artériás érbetegek kezelése során mindenképpen számolni kell a betegség teljes érrendszert involváló természetével, és a körültekintő, komplex terápia mellett is számítani kell a betegség progressziójára, súlyos cardialis, valamint cerebralis események bekövetkeztére, amelyek a beteg halálához is vezethetnek.
Hospital and long-term prognosis of patients with non-ST-segment elevation myocardial infarction
Authors: Jánosi András , Várnai Dániel , Ádám Zsófia , Surman Adrienn , Vas Katalin
Published: November 2008

A szerzők 139, nem ST-elevációs infarktus miatt kezelt betegük adatait elemzik. Vizsgálják a betegek kórházi és késői prognózisát, egyes echokardiográfiás adatok prognózissal való összefüggését, valamint a kórházból elbocsátott betegek esetén a szekunder prevenció szempontjából ajánlott gyógyszeres kezelés gyakoriságát. Az utánkövetés a betegek 98%-ában sikeres volt, a bekövetkezett eseményekről, illetve az utánkövetés idején alkalmazott gyógyszeres kezelésről postai kérdőív útján szereztek adatokat. A nők átlagéletkora 78,6, a férfiaké 71,4 év volt. A kezelt betegeknél gyakori volt a társbetegségek (hypertonia, diabetes mellitus, korábbi ischaemiás szívbetegség) előfordulása. A kórházi kezelés időszakában 30 betegnél (22%) történt koronarográfia, és 29 betegnél revascularisatiós beavatkozásra is sor került. A kórházi halálozás 15% volt, az utánkövetés háromnegyed éve alatt 17%-os halálozást észleltek. A kórházban, illetve az utánkövetési idő alatt meghalt betegek szignifikánsan idősebbek voltak azoknál, akik életben maradtak. Egyes echokardiográfiás adatok (ejekciós frakció, végszisztolés átmérő, szegmentális falmozgászavar és a mitralis insufficientia nagysága) prognosztikus jelentőségűnek bizonyultak, mivel szignifikánsan különböztek az életben maradt és a meghalt betegek esetén. A kórházból elbocsátott betegek igen magas arányban részesültek a másodlagos prevenció szempontjából fontosnak ítélt gyógyszeres kezelésben (aszpirin, béta-blokkoló, ACE-gátló, statin). Az utánkövetés idején sem csökkent ezen gyógyszerek használatának aránya, ami a betegek jó compliance-ét igazolja.
Cirrhosis and cholelithiasis. Laparoscopic or open cholecystectomy?
Authors: Déry Levente , Galambos Zoltán , Kupcsulik Péter , Lukovich Péter
Published: November 2008

Napjainkban az epehólyag-kövesség esetében a laparoszkópos cholecystectomia a standard műtéti megoldás. Az ellenjavallatok köre csökkent, ma már nem számít egyértelmű kontraindikációnak például a korábbi hasi műtét, a súlyos epehólyag-gyulladás, illetve a graviditás sem. A laparoszkópos technika előnye és haszna májcirrhoticus betegek esetében még bizonytalan.
Módszer és betegek:
A Semmelweis Egyetem I. Sebészeti Klinikáján 1996 és 2006 között 52, májcirrhosisban szenvedő és epehólyag-kövesség miatt műtétre került beteg adatait dolgozták fel retrospektív tanulmány formájában. A nő-férfi arány 2,7:1, az átlagéletkor 58,5 év (31–87) volt. A betegek Child szerinti megoszlása: A = 36, B = 14 és C = 2. Huszonhárom hagyományos (open cholecystectomia – OC) és 29 laparoszkópos (LC) cholecystectomiát végeztek, az utóbbiak közül 4 esetben konverzióra kényszerültek.
Eredmények:
Az átlagos műtéti idő Child A, B cirrhoticus betegeknél LC esetében 86,5 perc, hagyományos műtétnél 86,21 perc volt. Child C cirrhoticus betegeknél mindkét esetben nyílt cholecystectomia történt, az átlagos műtéti idő 81,5 perc volt. Posztoperatív szövődmény (Child A, B) 8 esetben fordult elő (LC/1, OC/7), míg a Child C pácienseknél mindkét esetben. Az átlagos kórházi tartózkodás 7,6 (LC), illetve 12,45 (OC) nap volt. Ugyanez a Child C betegeknél 28 napra emelkedett. A posztoperatív szakban 4 beteget vesztettek el, mindegyikük nyílt cholecystectomián esett át, Child B (3 beteg), illetve Child C (1 beteg) stádiumú májcirrhosisban szenvedett, és befolyásolhatatlan hepatorenalis szindróma alakult ki.
Következtetés:
Eredményük alapján kompenzált, Child A és B stádiumú cirrhoticus betegeknél az LC biztonságos eljárás. Bár a májcirrhosis a műtéti kockázatot extrém mértékben megnöveli, valamint a szövődmények lehetőségét, a hospitalizációt és a műtét idejét is emeli, a cirrhoticus betegek szimptómás cholelithiasisa egyértelmű műtéti javallatot képez.
Successful clearing of hepatitis C virus after liver lobectomy in a patient with hepatocellular carcinoma
Authors: Wimmer Alexandra , Fehér János , Lengyel Gabriella
Published: November 2008

A krónikus B- és C-hepatitis talaján gyakran alakul ki hepatocellularis carcinoma. A hepatitis B-vírus direkt módon, a hepatitis C-vírus indirekt módon játszik szerepet a hepatocarcinogenesisben.Célkitűzés:Egy olyan különlegesen érdekes eset demonstrálása, amelynek során az idejében felfedezett duplex hepatocellularis carcinoma műtéti megoldását követően kombinált PEG-interferon és ribavirin kombinált kezelés a hepatitis C-vírus eliminálásához vezetett.Esetbemutatás:Ötvenhárom éves férfi beteg anamnézisében krónikus C-hepatitis-fertőzés szerepel. 1995-ben a szövettani vizsgálat már májcirrhosist igazolt. Egy évre rá hagyományos interferonkezelésre nonreszponder volt. A CT-vizsgálat 2002-ben többgócú térfoglaló folyamatot igazolt a májban. A citológiai vizsgálattal is alátámasztott operábilis hepatocellularis carcinoma miatt bal oldali hepatolobectomia történt. A műtét után 4 évvel egy évig tartó PEG-interferon-α-2a- és ribavirinkezelésre virológiailag negatívvá vált.Következtetés:Krónikus májbetegségekben több gócból is kiindulhat neoplasztikus folyamat egy időben. A PEG-interferon- és ribavirinkezelés hatásos lehet előrehaladott krónikus májfolyamatok esetén is, akár a már kialakult hepatocellularis carcinoma műtéti eltávolítását követően.
Lipedema, a hardly known disease: diagnosis, associated illnesses and therapy
Authors: Wenczl Enikő , Daróczy Judit
Published: November 2008

A lipoedema gyakori, mégis ritkán diagnosztizált vagy számos esetben tévesen elhízásnak véleményezett betegség, amely csaknem kizárólag a nőket érinti. A subcutan zsírszövet szimmetrikus, körülírt, előrehaladott stádiumban torzító felszaporodása jellemzi elsősorban a lábakon, amely lokálisan nyirokoedemával társul. Spontán és nyomásra a bőr fájdalmas, a kis bőrerek rupturája gyakori. A vastag láb, amely igen gyakori panasz, egyik lehetséges oka a lipoedema. Fontos elkülöníteni az obesitas és a lipohypertrophia mellett a primer és a szekunder nyirokoedemától. Gyakran társul krónikus vénás és lymphás elégtelenséggel, korai degeneratív ízületi elváltozásokkal és elhízással. A tünetegyüttest sokszor nem ismerik fel, és a kezelési lehetőségek széles körben nem ismertek. A kezelés nélkül maradt betegek igen frusztrálónak érzik az állapotukat, ami pszichés zavarokhoz vezet. A közelmúltig kizárólag konzervatív kezelés (manuális vagy intermittáló pneumatikus drenázs, kompresszió és gyógytorna kombinációja) volt lehetséges. Napjainkban ez kiegészült sebészi kezeléssel (zsírleszívás). A lipoedema jelentőségét meghatározza a hozzá társuló, illetve az általa szekunder módon okozott társbetegségek (ízületi betegségek, vénás betegségek, nyirokoedema, obesitas, pszichés zavarok) együttese. A betegség prognózisa annál rosszabb, minél több betegség kombinálódik. Ennek megelőzése és késleltetése érdekében elengedhetetlen a kórkép felismerése és a lipoedemás betegek szakszerű kezelése és gondozása.
A Delicate Dance: Negotiating the Doctor-Patient Relationship During Cancer Treatment
Authors: Mariscotti Janine
Published: November 2008

The author reflects on the intricate dance of the patient–oncologist relationship experienced during her cancer journey.
Homeodomain transcription factor NKX2.2 functions in immature cells to control enteroendocrine differentiation and is expressed in gastrointestinal neuroendocrine tumors
Authors: Wang Yu-Cheng , Gallego-Arteche Emerick , Iezza Gioia , Yuan Xiaochen , Matli Mary R , Choo Su-Pin , Zuraek Marlene B , Gogia Ravi , Lynn Francis C , German Michael S , Bergsland Emily K , Donner David B , Warren Robert S , Nakakura Eric K
Published: November 2008

The homeodomain transcription factor NKX2.2 is necessary for neuroendocrine (NE) differentiation in the central nervous system and pancreas. NE tumors derived from the gut are defined by their NE phenotype, which is used for diagnosis and contributes to tumorigenicity. We hypothesized that NKX2.2 is important for NE differentiation in normal and neoplastic gut. NKX2.2 and NE marker expression was investigated in the small intestine of embryonic and adult mice using immunofluorescence (IF). To determine the role of NKX2.2 in NE differentiation of the intestine, the phenotype of Nkx2.2 (−/−) mice was examined by IF and real-time (RT)-PCR. NKX2.2 and NE marker expression in human NE tumors of the gut and normal tissues were evaluated by immunohistochemistry and qRT-PCR. NKX2.2 expression was detected in the intervillus/crypt regions of embryonic and adult mouse intestine. Co-expression of Nkx2.2 with neurogenin3 (NEUROG3) and hormones was observed in the adult intestinal crypt compartment, suggesting NKX2.2 functions in NEUROG3-positive endocrine progenitors and newly differentiated endocrine cells. In the intestine of Nkx2.2 (−/−) mice, we found a dramatic reduction in the number of cells producing numerous hormones, such as serotonin, gastrin, cholecystokinin, somatostatin, glucagon-like peptide 1 (GLP-1), and secretin, but an increase in cells producing ghrelin. NKX2.2 was expressed in most (24 of 29) human NE tumors derived from diverse primary sites. We conclude NKX2.2 functions in immature endocrine cells to control NE differentiation in normal intestine and is expressed in most NE tumors of the gut, and is therefore a novel target of diagnosis for patients with gastrointestinal NE tumors.
Cell cycle control of pituitary development and disease
Authors: Quereda Victor , Malumbres Marcos
Published: November 2008

The pituitary gland regulates diverse physiological functions, including growth, metabolism, reproduction, stress response, and ageing. Early genetic models in the mouse taught us that the pituitary is highly sensitive to genetic alteration of specific cell cycle regulators such as the retinoblastoma protein (pRB) or the cell cycle inhibitor p27Kip1. The molecular analysis of human pituitary neoplasias has now corroborated that cell cycle deregulation is significantly implicated in pituitary tumorigenesis. In particular, proteins involved in cyclin-dependent kinase regulation or the pRB pathway are altered in nearly all human pituitary tumors. Additional cell cycle regulators such as PTTG1/securin may have critical roles in promoting genomic instability in pituitary neoplasias. Recent experimental data suggest that these cell cycle regulators may have significant implications in the biology of putative progenitor cells and pituitary homeostasis. Understanding how cell cycle regulation controls pituitary biology may provide us with new therapeutic approaches against pituitary diseases.
Shining a Light on Sediment‐Associated Algae
Authors: MacIntyre Hugh L.
Published: November 2008

Kromkamp, Jacco C., Jody F. C. de Brouwer, Gérard F. Blanchard, Rodney M. Forster, and Véronique Créach, editors. 2006. Functioning of microphytobenthos in estuaries. The University of Chicago Press, Chicago, Illinois. x + 262 p. $78.00, ISBN: 90‐6984‐453‐2 (alk. paper).
ARCTIC CLIMATE CHANGE AND ITS IMPACTS ON THE ECOLOGY OF THE NORTH ATLANTIC
Authors: Greene Charles H. , Pershing Andrew J. , Cronin Thomas M. , Ceci Nicole
Published: November 2008

Arctic climate change from the Paleocene epoch to the present is reconstructed with the objective of assessing its recent and future impacts on the ecology of the North Atlantic. A recurring theme in Earth's paleoclimate record is the importance of the Arctic atmosphere, ocean, and cryosphere in regulating global climate on a variety of spatial and temporal scales. A second recurring theme in this record is the importance of freshwater export from the Arctic in regulating global‐ to basin‐scale ocean circulation patterns and climate. Since the 1970s, historically unprecedented changes have been observed in the Arctic as climate warming has increased precipitation, river discharge, and glacial as well as sea‐ice melting. In addition, modal shifts in the atmosphere have altered Arctic Ocean circulation patterns and the export of freshwater into the North Atlantic. The combination of these processes has resulted in variable patterns of freshwater export from the Arctic Ocean and the emergence of salinity anomalies that have periodically freshened waters in the North Atlantic. Since the early 1990s, changes in Arctic Ocean circulation patterns and freshwater export have been associated with two types of ecological responses in the North Atlantic. The first of these responses has been an ongoing series of biogeographic range expansions by boreal plankton, including renewal of the trans‐Arctic exchanges of Pacific species with the Atlantic. The second response was a dramatic regime shift in the shelf ecosystems of the Northwest Atlantic that occurred during the early 1990s. This regime shift resulted from freshening and stratification of the shelf waters, which in turn could be linked to changes in the abundances and seasonal cycles of phytoplankton, zooplankton, and higher trophic‐level consumer populations. It is predicted that the recently observed ecological responses to Arctic climate change in the North Atlantic will continue into the near future if current trends in sea ice, freshwater export, and surface ocean salinity continue. It is more difficult to predict ecological responses to abrupt climate change in the more distant future as tipping points in the Earth's climate system are exceeded.
THE TRANS‐ATLANTIC HISTORY OF DIVERSITY AND BODY SIZE IN ECOLOGICAL GUILDS
Authors: Vermeij Geerat J. , Dietl Gregory P. , Reid David G.
Published: November 2008

Geographically separate biotas often show differences in species composition, diversity, and adaptations. Such differences, which often reflect historical differences in regimes of productivity and selection, have received little attention from ecologists. Here we concentrate on diversity and maximum body size in 18 guilds of shallow‐water marine shell‐bearing mollusks and barnacles from the European and North American sides of the temperate North Atlantic. These guilds represent suspension‐feeders (epifaunal, shallow infaunal, and deep infaunal), chemosymbiotic bivalves, predators, and grazers. Geographic patterns among Recent guilds were compared to those during Pliocene and early Miocene time in order to determine how diversity and maximum size changed over the last 17 million years in the face of high levels of extinction and species invasion.

Recent European guilds are generally more diverse than their American counterparts, a finding consistent with previous biota‐wide analyses. Diversity within Pliocene guilds was often higher on the American side, but this stems in part from the large subtropical component in preserved temperate Pliocene guilds in Virginia but not in Europe.

The largest species in hard‐bottom guilds in Europe reach greater sizes than those in comparable American guilds, but for sand‐bottom guilds, American species almost always attain greater sizes than their European counterparts. These size differences have changed little since early Miocene time despite high levels of Pliocene and Pleistocene extinction in invasion, particularly on the American side. Large‐bodied species are overrepresented among both extinct and invading lineages, meaning that lineage replacement has been the rule for the largest species in guilds on both sides of the Atlantic.

Together with previous studies, these results may imply that sand‐bottom environments in North America have been more productive and have experienced more far‐reaching escalation between shell‐bearing species and their predators than their European counterparts since early Miocene time. The Pliocene to Recent record of hard‐bottom guilds implies that productivity and/or escalation in these systems may have been higher on the European side than in eastern North America. Shallow‐water guilds on opposite sides of the Atlantic have retained differences despite great upheavals caused by extinctions and invasions during the last 3 million years.
THE RELATION BETWEEN PRODUCTIVITY AND SPECIES DIVERSITY IN TEMPERATE–ARCTIC MARINE ECOSYSTEMS
Authors: Witman Jon D. , Cusson Mathieu , Archambault Philippe , Pershing Andrew J. , Mieszkowska Nova
Published: November 2008

Energy variables, such as evapotranspiration, temperature, and productivity explain significant variation in the diversity of many groups of terrestrial plants and animals at local to global scales. Although the ocean represents the largest continuous habitat on earth with a vast spectrum of primary productivity and species richness, little is known about how productivity influences species diversity in marine systems. To search for general relationships between productivity and species richness in the ocean, we analyzed data from three different benthic marine ecosystems (epifaunal communities on subtidal rock walls, on navigation buoys in the Gulf of St. Lawrence, and Canadian Arctic macrobenthos) across local to continental spatial scales (<20 to >1000 km) using a standardized proxy for productivity, satellite‐derived chlorophyll α Theoretically, the form of the function between productivity and species richness is either monotonically increasing or decreasing, or curvilinear (hump‐ or U‐shaped). We found three negative linear and three hump‐shaped relationships between chlorophyll α and species richness out of 10 independent comparisons. Scale dependence was suggested by more prevalent diversity–productivity relationships at smaller (local, landscape) than larger (regional, continental) spatial scales. Differences in the form of the functions were more closely allied with community type than with scale, as negative linear functions were restricted to sessile epifauna while hump‐shaped functions occurred in Arctic macrobenthos (mixed epifauna, infauna). In two of the data sets, (St. Lawrence epifauna and Arctic macrobenthos) significant effects of chlorophyll α co‐varied with the effects of salinity, suggesting that environmental stress as well as productivity influences diversity in these marine systems. The co‐varying effect of salinity may commonly arise in broad‐scale studies of productivity and diversity in marine ecosystems when attempting to sample the largest range of productivity, often encompassing a coastal–oceanic gradient.
THE INFLUENCE OF CLIMATE AND SPECIES COMPOSITION ON THE POPULATION DYNAMICS OF TEN PRAIRIE FORBS
Authors: Adler Peter B. , HilleRisLambers Janneke
Published: November 2008

Understanding the relative roles of climate and species interactions in regulating population dynamics, one of the oldest challenges in ecology, is now a prerequisite for predicting species responses to climate change. A lack of case studies limits our ability to generalize about the factors that have regulated populations in the past and will be important in the future. Here, we take a first step toward identifying the drivers of plant population dynamics by studying the influence of climate and species interactions on the recruitment and survival of ten forb species from a Kansas (USA) prairie. Combining a long‐term demographic data set with a Bayesian hierarchical‐modeling approach, we fit models in which annual survival and recruitment rates are driven by precipitation, temperature, and species composition. Although the effects of these covariates differed among species, three general patterns emerged. First, climate had a greater influence than species composition on historical population dynamics. Second, forecasted increases in mean temperatures are likely to impact the population growth of these species more than future changes in precipitation or composition. Third, the significant effects of both climate and species composition on recruitment suggest that range expansions will be particularly difficult to forecast. Based on these patterns, we recommend field experiments to evaluate the ability of plant species to recruit at expanding range margins under warmer temperatures.
PLANT AND MICROBIAL CONTROLS ON NITROGEN RETENTION AND LOSS IN A HUMID TROPICAL FOREST
Authors: Templer Pamela H. , Silver Whendee L. , Pett-Ridge Jennifer , M. DeAngelis Kristen , Firestone Mary K.
Published: November 2008

Humid tropical forests are generally characterized by the lack of nitrogen (N) limitation to net primary productivity, yet paradoxically have high potential for N loss. We conducted an intensive field experiment with 15NH4 and 15NO3 additions to highly weathered tropical forest soils in Puerto Rico to determine the relative importance of N retention and loss mechanisms. Over one‐half of all the NH4+ produced was rapidly converted to NO3− via the process of gross nitrification. During the first 24 hours, plant roots took up 28% of the inorganic N produced, dominantly as NH4+, and were a greater sink for N than soil microbial biomass. Soil microbes were not a significant sink for added 15NH4+ or 15NO3− during the first 24 hours, and only for 15NH4+ after 7 days. Patterns of microbial community composition, as determined by terminal restriction fragment length polymorphism analysis (TRFLP), were weakly but significantly correlated with nitrification and denitrification to N2O. Rates of dissimilatory NO3− reduction to NH4+ (DNRA) were high in this forest, accounting for up to 25% of gross NH4+ production and 35% of gross nitrification. DNRA was a major sink for NO3−, which may have contributed to the lower rates of N2O and leaching losses. Despite considerable N conservation via DNRA and plant NH4+ uptake, the fate of ∼45% of the NO3− produced and 4% of the NH4+ produced were not measured in our fluxes, suggesting that other important pathways for N retention and loss (e.g., denitrification to N2) are important in this system. The high proportion of mineralized N that was rapidly nitrified and the fates of that NO3− highlight the key role of gross nitrification as a proximate control on N retention and loss in humid tropical forest soils. Furthermore, our results demonstrate the importance of the coupling between DNRA and plant uptake of NH4+ as a potential N‐conserving mechanism within tropical forests.
ENVIRONMENTAL FLUCTUATIONS INDUCE SCALE‐DEPENDENT COMPENSATION AND INCREASE STABILITY IN PLANKTON ECOSYSTEMS
Authors: Downing Amy L. , Brown Bryan L. , Perrin Elizabeth M. , Keitt Timothy H. , Leibold Mathew A.
Published: November 2008

The temporal stability of aggregate community and ecosystem properties is influenced by the variability of component populations, the interactions among populations, and the influence of environmental fluctuations on populations. Environmental fluctuations that enhance population variability are generally expected to destabilize community and ecosystem properties, but this will depend on the degree to which populations are synchronized in their dynamics. Here we use seminatural experimental ponds to show that reduced synchrony among zooplankton taxa increases the temporal stability of zooplankton density, abundance, and ecosystem productivity in fluctuating environments. However, asynchrony only occurs at long timescales (∼80‐day periods) and under recurring environmental perturbations. At shorter timescales (∼10‐day periods) and in constant environments, synchronous dynamics dominate. Our findings support recent theory indicating that compensatory dynamics can stabilize communities and ecosystems. They further indicate that environmental fluctuations can enhance the likelihood of long‐period asynchrony and thus stabilize community and ecosystem properties despite their short term destabilizing effects.
TRANSITIONS FROM STABLE EQUILIBRIA TO CHAOS, AND BACK, IN AN EXPERIMENTAL FOOD WEB
Authors: Becks Lutz , Arndt Hartmut
Published: November 2008

The question of whether deterministic chaos occurs in natural populations has been discussed since the 1970s following the discovery that simple population models can generate chaotic dynamics. Natural populations undergo a diverse mixture of deterministic and stochastic processes that define population dynamics. In most habitats populations are also exposed to changes in biotic and abiotic parameters. Models predict that shifts in ecological parameters may lead to a transition between deterministic chaos, stable equilibria, and limit cycles, yet clear examples from empirical studies are rare. However, such transitions should be considered when discussing the occurrence of chaos in nature because ecological time series are in general short and have large sampling intervals. Here we document short‐term transitions in population dynamics to and from chaos in an experimental system. Manipulation of only one experimental parameter (chemostat dilution rate) in a multi‐species food web of two bacteria and a bacterivorous ciliate showed that switching between different dynamic behaviors occured with surprising rapidity in the microbial populations. Thus, short periods of chaotic dynamics may easily be overlooked in field observations.
FLORIVORES LIMIT COST OF MUTUALISM IN THE YUCCA–YUCCA MOTH ASSOCIATION
Authors: Segraves Kari A.
Published: November 2008

Multispecies interactions may have important consequences for the ecology and evolution of mutualism by changing the cost‐to‐benefit ratio. Here I determine whether florivorous beetles can limit moth populations and influence the costs of the mutualism between yuccas and their pollinating moths. Yucca moths actively pollinate yucca flowers, and their larvae feed on a portion of the seeds. I used a manipulative field experiment to examine the hypothesis that the characteristic feeding behavior of the florivorous beetle Hymenorus densus may increase mortality of pollinator moth eggs and reduce the costs incurred by the plant. The results indicated that H. densus consumes moth eggs and that the consumption rate matches levels of moth mortality typically observed in these populations. On average, beetles consumed 1–2 eggs per flower, which translates into an increase in seed production of ∼16–32% per fruit. Counterintuitively, these results suggest that florivores can limit moth populations and reduce the costs incurred by the plant.
EVALUATING SIGNATURES OF GLACIAL REFUGIA FOR NORTH ATLANTIC BENTHIC MARINE TAXA
Authors: Maggs Christine A. , Castilho Rita , Foltz David , Henzler Christy , Jolly Marc Taimour , Kelly John , Olsen Jeanine , Perez Kathryn E. , Stam Wytze , Väinölä Risto , Viard Frédérique , Wares John
Published: November 2008

A goal of phylogeography is to relate patterns of genetic differentiation to potential historical geographic isolating events. Quaternary glaciations, particularly the one culminating in the Last Glacial Maximum ∼21 ka (thousands of years ago), greatly affected the distributions and population sizes of temperate marine species as their ranges retreated southward to escape ice sheets. Traditional genetic models of glacial refugia and routes of recolonization include these predictions: low genetic diversity in formerly glaciated areas, with a small number of alleles/haplotypes dominating disproportionately large areas, and high diversity including “private” alleles in glacial refugia. In the Northern Hemisphere, low diversity in the north and high diversity in the south are expected. This simple model does not account for the possibility of populations surviving in relatively small northern periglacial refugia. If these periglacial populations experienced extreme bottlenecks, they could have the low genetic diversity expected in recolonized areas with no refugia, but should have more endemic diversity (private alleles) than recently recolonized areas. This review examines evidence of putative glacial refugia for eight benthic marine taxa in the temperate North Atlantic. All data sets were reanalyzed to allow direct comparisons between geographic patterns of genetic diversity and distribution of particular clades and haplotypes including private alleles. We contend that for marine organisms the genetic signatures of northern periglacial and southern refugia can be distinguished from one another. There is evidence for several periglacial refugia in northern latitudes, giving credence to recent climatic reconstructions with less extensive glaciation.
ANTI‐HERBIVORE PROTECTION BY MUTUALISTIC SPIDERS AND THE ROLE OF PLANT GLANDULAR TRICHOMES
Authors: Romero Gustavo Q. , Souza José César , Vasconcellos-Neto João
Published: November 2008

Although specific associations between spiders and particular types of plants have been reported for several taxonomic groups, their consequences for spiders and plants are still poorly understood. The most common South American lynx spiders, Peucetia flava and P. rubrolineata, live strictly associated with various plant species that have glandular trichomes. To understand more about these spider–plant relationships, we investigated the influence of the spiders on the fitness of a neotropical glandular shrub (Trichogoniopsis adenantha) and on the arthropod community structure on the plant. We also tested whether glandular hairs provided any benefit to the spiders. Spiders reduced the abundance of several species and guilds of herbivores on the leaves and inflorescences. Consequently, damage to the leaves, capitula, ovaries, corollas, and stigmas caused by leaf‐mining and chewing insects, as well as endophagous insects, were strongly reduced in the presence of Peucetia spp. Although the spiders fed on flower visitors, their negative influence on ovary fertilization was only marginally nonsignificant (P = 0.065). Spiders on plants of Trichogoniopsis adenantha that fed on common fruit flies that had died before adhering to the glandular trichomes did not lose body mass. However, those living on plants without stalked glandular trichomes (Melissa officinalis) did not feed on dead flies and lost 13–20% of their biomass. These results indicate that Peucetia spiders are effective plant bodyguards and that when there is limited live prey they may feed on insect carcasses adhered to glandular trichomes. Since several spider species of the genus Peucetia live strictly associated with glandular trichome‐bearing plants in neotropical, Neartic, Paleartic, and Afrotropical regions, this type of facultative mutualism involving Peucetia and glandular plants may be common worldwide.
THE COST OF REPRODUCTION AND EXPERIENCE‐DEPENDENT VITAL RATES IN A SMALL PETREL
Authors: Sanz-Aguilar Ana , Tavecchia Giacomo , Pradel Roger , Mínguez Eduardo , Oro Daniel
Published: November 2008

Life history theory predicts that higher levels of reproductive investment entail higher reproductive costs especially among young and inexperienced individuals that might not optimize reproductive investment. Using a long‐term individual and state‐dependent capture–recapture data on Storm Petrels (Hydrobates pelagicus) we analyzed whether breeding experience and current breeding investment were associated with the expression of the cost of reproduction in terms of reduced survival and/or future breeding performance. We found a positive relationship between current breeding investment, breeding experience, and future survival and an improvement in breeding performance with individual experience independently of the previous breeding outcome. Our results suggest that the survival cost paid by first‐time breeders and the positive correlation between reproduction and survival corresponds to selection against low quality birds unrelated to the breeding effort. Our work outlines the need to investigate the effect of multiple individual traits on different life history trade‐offs simultaneously.
CLIMATE AND RECRUITMENT OF ROCKY SHORE INTERTIDAL INVERTEBRATES IN THE EASTERN NORTH ATLANTIC
Authors: Broitman Bernardo R. , Mieszkowska Nova , Helmuth Brian , Blanchette Carol A.
Published: November 2008

Studies of the impacts of climate and climate change on biological systems often attempt to correlate ecological responses with basin‐scale indices such as the North Atlantic Oscillation (NAO). However, such correlations, while useful for detecting long‐term trends, are unable to provide a mechanism linking the physical environment and ecological processes. Here we evaluate the effects of the NAO on recruitment variability of rocky intertidal invertebrates in the North Atlantic examining two possible climate‐related pathways. Using a highly conservative test we interpret associations with the NAO integrated over a season (three months) as an indicator of atmospheric effects on newly settled recruits (NAO3), and the effects of the NAO integrated over six months (NAO6) as an indicator of changes in ocean circulation affecting patterns of larval transport. Through an extensive literature survey we found 13 time series, restricted to southwest Ireland and Britain and comprising five species, that could be used for statistical analysis. Significant correlations with NAO3, our proxy for atmospheric effects, were observed in the south‐central domain of our study region (southwest Ireland and south England). Significant correlations with NAO6, the proxy for ocean circulation effects, were detected on southwest Ireland. The associations were detected for three (two barnacles and a topshell) at two sites. These results suggest that the NAO can have effects on the recruitment of intertidal invertebrates through different pathways linked to climate and be distributed heterogeneously in space. Based on previous evidence and the sign and geographic location of significant correlations, we suggest that winter NAO effects are likely to occur as a result of effects on the survival of early life stages settling during spring or through changes in phenology. Our results argue that a combination of modeling and synthesis can be used to generate hypotheses regarding the effects of climate on recruitment and aid in the design of field‐based tests of explicit ecological mechanisms.
Seven Decades of Calcium Depletion in Organic Horizons of Adirondack Forest Soils
Authors: Johnson A. H. , Moyer A. , Bedison J. E. , Richter S. L. , Willig Sarah Andersen
Published: November 2008

We used repeated sampling of the forest floor to determine if there was a net loss of Ca from organic horizons of Adirondack forest soils between 1930 and 2004. In 1984, we established 48 permanent plots in spruce–fir, northern hardwood, and pine stands located in areas sampled by Carl C. Heimburger in the early 1930s. Following Heimburger's protocols and analytical methods, we measured pH and dilute‐HCl‐extractable Ca in Oe and Oa horizons, and determined that there was a statistically significant decrease in Ca concentration during the 1932 to 1984 interval. In the 36 plots that we could locate in 2004, we again sampled organic horizons. During the >70‐yr interval, HCl‐extractable Ca concentrations in the Oe and Oa horizons decreased in each forest type (P < 0.05). We also measured NH4Cl‐extractable Ca and Al in the 1984 and 2004 samples and found a significant decrease in Ca concentration in the pooled Oe horizons. High‐elevation spruce–fir plots showed a Ca loss rate between 1984 and 2004 of 7.6 to 9.8 kg ha−1 yr−1 This compares well with a 4‐yr Ca cycling study conducted in an equivalent spruce–fir forest at Whiteface Mt. in the Adirondacks, which showed an annual forest floor Ca loss of 8.4 kg ha−1 yr−1 Based on uptake and anion flux data from the Whiteface Mt. study, we estimated that about 25 to 30% of the 1984 to 2004 forest floor Ca loss in the spruce–fir plots is attributable to leaching driven by atmospheric SO42− deposition.
Soil Profile Properties in Relation to Soil Redistribution by Intense Tillage on a Steep Hillslope
Authors: Zhang J. H. , Nie X. J. , Su Z. A.
Published: November 2008

Little is known about soil redistribution by tillage and its impact on the properties of soil profiles with thin soil layers on hillslopes. In this study, consecutive tillage by hoeing was performed 5 and 15 times on an Orthic Regosol within a steep hillslope landscape of the Sichuan Basin, China, to simulate the impact of short‐ and long‐term tillage on soil profile properties at different slope positions. After intense tillage, significant changes in 137Cs inventories of the soil occurred in the summit and toeslope positions. The soil profile (originally ≤0.3 m in depth) disappeared on the slope summit due to intense soil downslope translocation, and the soil profile was truncated in upper slope positions in the proximity of the summit, while a thickened soil profile was present in toeslope positions, where the original soil profile was buried. The summit was characterized by an exposure of bedrock corresponding to areas of 4.77 and 10.0% of the experimental plot for 5 and 15 tillage operations, respectively. Soil organic C (SOC) and P were completely depleted with the disappearance of soil profiles at the summit position, while a substantial increase in SOC and extractable P inventories of the post‐tillage soil profile was found in the toeslope position. Intense tillage caused remarkable soil redistribution within the landscape of the steep slope, resulting in net soil loss and gain close to the upslope and downslope boundaries of the field, respectively. Tillage results in an intense transformation of soil profiles and the variation in soil properties in steeply sloping fields.
Near‐Saturated Hydraulic Properties in the Surface Layer of a Sandy Loam Soil under Conventional and Reduced Tillage
Authors: Daraghmeh O. A. , Jensen J. R. , Petersen C. T.
Published: November 2008

Information on the quantitative tillage effects on pore space and near‐saturated hydraulic characteristics is important to improve decision support systems for soil and environmental management. The purpose of this study was to determine the effect of conventional (CT) and reduced tillage (RT) on water retention and infiltration properties of an Agrudalf sandy loam surface soil under long‐term winter wheat (Triticum aestivum L.) cropping. Using tension disk infiltrometry, with supply pressure heads (h) from −15 to −120 mm, the steady‐state infiltration rate [i(h)] and hydraulic conductivity [K(h)] were highest shortly after tillage in October, followed by a steep decrease to minimum values in winter and a recovery to intermediate values during spring and early summer. The range in the temporal variation in saturated K was about 65 to 5 and 52 to 8 mm h−1 under CT and RT, respectively. Compared with CT, K(h) under RT was slightly lower shortly after tillage, similar during winter, and considerably higher during early summer. Changes in K were accompanied by temporal variations in pore space characteristics, indicating structural collapse during late autumn and early winter followed by structural recovery with aggregation during spring and summer. The air‐entry pressure head was highest under RT. The effective porosities were found to be smaller, by two to three orders of magnitude, than the equivalent fractional pore volumes estimated from the water retention curves determined on soil cores in the laboratory. Wheel traffic was found to obliterate any differences in hydraulic properties between the tillage treatments. Therefore, compared with CT, RT is likely to improve water availability and soil resilience but offers no comparative advantage for controlling wheel‐traffic‐induced topsoil compaction.
Testing a Grid‐Based Soil Erosion Model across Topographically Complex Landscapes
Authors: Bonilla Carlos A. , Norman John M. , Molling Christine C. , Karthikeyan K. G. , Miller Paul S.
Published: November 2008

This study was conducted to evaluate the overall performance of the Precision Agricultural‐Landscape Modeling System (PALMS) for calculating runoff and soil loss under cropped conditions. The PALMS model uses a lognormal distribution of saturated hydraulic conductivity across the fields to simulate typical soil heterogeneity within soil texture classes. Runoff and soil loss data were collected in three farm fields for a total of 75 runoff events during 2 yr under six cropping scenarios (alfalfa [Medicago sativa L.] and corn [Zea mays L.] no‐tilled, corn and soybean [Glycine max (L.) Merr.] moldboard plowed, and alfalfa and corn chisel plowed). For individual storms, calculated runoff and sediment loss from PALMS were compared with corresponding measurements for each farm during the entire cropping season. The coefficient of determination (r2) between runoff calculations and measurements was 0.84. The r2 between soil loss calculations and measurements with the storm‐by‐storm simulations during both seasons was 0.78. Based on these continuous simulation results, the PALMS calculations appear to have lower relative errors with large events than small events, a desirable result because large events are most important in assessing the environmental consequences of management practices.
Iron Oxyhydroxide Reduction in Simulated Wetland Soils: Effects of Mineralogical Composition of IRIS Paints
Authors: Rabenhorst Martin C. , Bourgault Rebecca R. , James Bruce R.
Published: November 2008

Reducing conditions in soils can be documented by the voltage measured between Pt and reference electrodes (Eh) or by using dyes like α,α‐dipyridyl for identifying reduced species (such as Fe2+). Indicator of Reduction in Soils (IRIS) tubes have been recently introduced as an alternative approach for documenting reducing conditions in soils, where a synthetic Fe oxyhydroxide painted on polyvinyl chloride tubes can be reduced, dissolved, and removed by respiring soil microorganisms. In order for the Fe oxyhydroxide paint to adhere to the tubes, it must be synthesized as a mixture of ferrihydrite and goethite. Based on thermodynamics, ferrihydrite is predicted to be more easily reduced at higher redox potentials than goethite. We hypothesized that IRIS tubes made using paint composed of different proportions of ferrihydrite and goethite would perform differently in wetland soils. This experiment evaluated the performance of IRIS tubes created using nine Fe oxyhydroxide paints with different proportions of ferrihydrite and goethite ranging from 15.2 to 70.9 mol % goethite. Tubes were evaluated following placement in mesocosms in the laboratory using two different wetland soil materials for 13 d. An ANOVA indicated that there were highly significant differences (P < 0.0001) in full or intermediate removal of paint due to paint type. In general, the extent of paint removal was inversely related to goethite content. The minimum goethite content needed to successfully manufacture IRIS tubes is approximately 40%, and we recommend that IRIS tubes not be used when the goethite content is beyond the range of 40 to 60 mol %.
Improved Analytical Techniques for Carbohydrates, Amino Compounds, and Phenols: Tools for Understanding Soil Processes
Authors: Olk Dan C.
Published: November 2008

A process‐level understanding of soil C and N cycling will be facilitated by accurate measurement of biochemical compounds in soil organic matter. This review summarizes some recent developments in analytical procedures for measuring soil carbohydrates, amino compounds (amino acids and amino sugars), and phenols. The emphasis is on methods for soil carbohydrates and amino compounds involving anion chromatography and pulsed amperometry, a sensitive form of detection that has otherwise not been widely used in soil science. This carbohydrate procedure has become a leading method, with high resolution, sensitivity, and reproducibility. The pulsed amperometry analysis for amino compounds may be incrementally better than the conventional approach by HCl extraction, cation exchange chromatography, ninhydrin derivatization, and detection by visible light absorption. The two amino approaches need more rigorous comparison with regard to extraction efficiency and sensitivity for each amino compound. The pulsed amperometry approach also needs evaluation in a wider range of research settings. A recently developed procedure for measuring soil phenols is based on plant biochemistry studies and distinguishes ether‐linked phenols (mostly vanillyl and syringyl) from ester‐linked phenols (mostly coumaric acid and ferulic acid). Its applications in a limited number of studies linked specific phenols to soil aggregation and C sequestration. It needs calibration with other phenol methods favored by soil scientists and biogeochemists, and it needs to be evaluated in a range of research settings. Like the pulsed amperometry analysis for amino compounds, this distinction of ether‐ and ester‐linked phenols is likely to complement existing techniques. A future goal will be the integration of results from complementary analyses for these biochemical compounds to help us better understand soil processes.
A New Method of Poultry Litter Application to Perennial Pasture: Subsurface Banding
Authors: Warren Jason G. , Sistani Karamat R. , Way Thomas R. , Mays David A. , Pote Daniel H.
Published: November 2008

Recently, incorporation of poultry litter by subsurface band application into pasture has been shown to reduce surface runoff transport of nutrients; however, data to evaluate the impact of this potential management strategy on forage production, forage nutrient concentrations, or the accumulation of soil nutrients after multiyear applications is limited. Therefore, two experiments, one in bermudagrass [Cynodon dactylon (L.) Pers.] and one in tall fescue (Festuca arundinacea Schreb.) were initiated in which treatments included (i) a standard commercial fertilizer application, (ii) a surface broadcast litter application, (iii) poultry litter applied in subsurface bands placed 25 cm apart, and (iv) poultry litter applied in subsurface bands placed 38 cm apart. The experiments were conducted for 3 yr on a Hartsells (fine‐loamy, siliceous, subactive, thermic Typic Hapludult) soil at Crossville, AL, and showed that subsurface band applications resulted in forage yields equivalent to those achieved by conventional broadcast litter applications. Subsurface band applications also did not generally impact forage N, P, and K concentrations compared with surface litter applications. Three years of subsurface band applications to a depth of approximately 4 cm did not significantly alter the Mehlich 3 extractable nutrient content of soils collected at a depth of 0 to 15 cm. Data suggest, however, that subsurface band application would allow increases in subsurface movement of nutrients, as was evidenced by increased Cu concentrations at the 15‐ to 30‐cm depth. The data suggest that the environmental benefits of subsurface band application of poultry litter into grass production systems are achieved without detrimental impacts on forage productivity or nutrient concentrations.