bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of parasites from salmon farms on productivity of wild salmon
Authors: Krkošek Martin , Connors Brendan M. , Morton Alexandra , Lewis Mark A. , Dill Lawrence M. , Hilborn Ray
Published: August 2011

The ecological risks of salmon aquaculture have motivated changes to management and policy designed to protect wild salmon populations and habitats in several countries. In Canada, much attention has focused on outbreaks of parasitic copepods, sea lice (
Lepeophtheirus salmonis
), on farmed and wild salmon in the Broughton Archipelago, British Columbia. Several recent studies have reached contradictory conclusions on whether the spread of lice from salmon farms affects the productivity of sympatric wild salmon populations. We analyzed recently available sea lice data on farms and spawner–recruit data for pink (
Oncorhynchus gorbuscha
) and coho (
Oncorhynchus kisutch
) salmon populations in the Broughton Archipelago and nearby regions where farms are not present. Our results show that sea lice abundance on farms is negatively associated with productivity of both pink and coho salmon in the Broughton Archipelago. These results reconcile the contradictory findings of previous studies and suggest that management and policy measures designed to protect wild salmon from sea lice should yield conservation and fishery benefits.
An integrated model of fixational eye movements and microsaccades
Authors: Engbert Ralf , Mergenthaler Konstantin , Sinn Petra , Pikovsky Arkady
Published: August 2011

When we fixate a stationary target, our eyes generate miniature (or fixational) eye movements involuntarily. These fixational eye movements are classified as slow components (physiological drift, tremor) and microsaccades, which represent rapid, small-amplitude movements. Here we propose an integrated mathematical model for the generation of slow fixational eye movements and microsaccades. The model is based on the concept of self-avoiding random walks in a potential, a process driven by a self-generated activation field. The self-avoiding walk generates persistent movements on a short timescale, whereas, on a longer timescale, the potential produces antipersistent motions that keep the eye close to an intended fixation position. We introduce microsaccades as fast movements triggered by critical activation values. As a consequence, both slow movements and microsaccades follow the same law of motion; i.e., movements are driven by the self-generated activation field. Thus, the model contributes a unified explanation of why it has been a long-standing problem to separate slow movements and microsaccades with respect to their motion-generating principles. We conclude that the concept of a self-avoiding random walk captures fundamental properties of fixational eye movements and provides a coherent theoretical framework for two physiologically distinct movement types.
Conservation of the C-type lectin fold for massive sequence variation in a
Treponema
diversity-generating retroelement
Authors: Le Coq Johanne , Ghosh Partho
Published: August 2011

Anticipatory ligand binding through massive protein sequence variation is rare in biological systems, having been observed only in the vertebrate adaptive immune response and in a phage diversity-generating retroelement (DGR). Earlier work has demonstrated that the prototypical DGR variable protein, major tropism determinant (Mtd), meets the demands of anticipatory ligand binding by novel means through the C-type lectin (CLec) fold. However, because of the low sequence identity among DGR variable proteins, it has remained unclear whether the CLec fold is a general solution for DGRs. We have addressed this problem by determining the structure of a second DGR variable protein, TvpA, from the pathogenic oral spirochete
Treponema denticola
. Despite its weak sequence identity to Mtd (∼16%), TvpA was found to also have a CLec fold, with predicted variable residues exposed in a ligand-binding site. However, this site in TvpA was markedly more variable than the one in Mtd, reflecting the unprecedented approximate 10
20
potential variability of TvpA. In addition, similarity between TvpA and Mtd with formylglycine-generating enzymes was detected. These results provide strong evidence for the conservation of the formylglycine-generating enzyme-type CLec fold among DGRs as a means of accommodating massive sequence variation.
Phylogenetic rate shifts in feeding time during the evolution of
Homo
Authors: Organ Chris , Nunn Charles L. , Machanda Zarin , Wrangham Richard W.
Published: August 2011

Unique among animals, humans eat a diet rich in cooked and nonthermally processed food. The ancestors of modern humans who invented food processing (including cooking) gained critical advantages in survival and fitness through increased caloric intake. However, the time and manner in which food processing became biologically significant are uncertain. Here, we assess the inferred evolutionary consequences of food processing in the human lineage by applying a Bayesian phylogenetic outlier test to a comparative dataset of feeding time in humans and nonhuman primates. We find that modern humans spend an order of magnitude less time feeding than predicted by phylogeny and body mass (4.7% vs. predicted 48% of daily activity). This result suggests that a substantial evolutionary rate change in feeding time occurred along the human branch after the human–chimpanzee split. Along this same branch,
Homo erectus
shows a marked reduction in molar size that is followed by a gradual, although erratic, decline in
H. sapiens
. We show that reduction in molar size in early
Homo
(
H. habilis
and
H. rudolfensis
) is explicable by phylogeny and body size alone. By contrast, the change in molar size to
H. erectus
,
H. neanderthalensis
, and
H. sapiens
cannot be explained by the rate of craniodental and body size evolution. Together, our results indicate that the behaviorally driven adaptations of food processing (reduced feeding time and molar size) originated after the evolution of
Homo
but before or concurrent with the evolution of
H. erectus
, which was around 1.9 Mya.
CD4+T cells from elite suppressors are more susceptible to HIV-1 but produce fewer virions than cells from chronic progressors
Authors: O'Connell Karen A. , Rabi S. Alireza , Siliciano Robert F. , Blankson Joel N.
Published: August 2011

Elite suppressors/controllers (ES) are HIV-1–infected individuals who maintain stable CD4+T-cell counts and viral loads of <50 copies/mL without antiretroviral therapy. Research has predominantly focused on immune factors contributing to the control of viral replication in these patients. A more fundamental question, however, is whether there are differences in the nature of CD4+T-cell infection in ES compared with viremic patients. Here, we compare chronic progressor (CP), ES, and uninfected donors in terms of three aspects of CD4+T-cell infection: cellular susceptibility to infection, death of infected cells, and production of virus from infected cells. Using multiple methods of infection and both single-cycle and replication-competent virus, we show that unmanipulated CD4+T-cell populations from ES are actually more susceptible to HIV-1 infection than those populations from CP. Depletion of highly susceptible cells in CP may contribute to this difference. Using 7AAD and AnnexinV staining, we show that infected cells die more rapidly than uninfected cells, but the increased death of infected cells from CP and ES is proportional. Finally, using an assay for measuring virus production, we show that virus production by cells from CP is high compared with virus production by cells from ES or uninfected donors. This higher virus production is linked to cellular activation levels. These data identify fundamental differences in chronic infection of ES and CP that likely contribute to differential HIV-1 disease progression.
Cranial asymmetry in Eocene archaeocete whales and the evolution of directional hearing in water
Authors: Fahlke Julia M. , Gingerich Philip D. , Welsh Robert C. , Wood Aaron R.
Published: August 2011

Eocene archaeocete whales gave rise to all modern toothed and baleen whales (Odontoceti and Mysticeti) during or near the Eocene-Oligocene transition. Odontocetes have asymmetrical skulls, with asymmetry linked to high-frequency sound production and echolocation. Mysticetes are generally assumed to have symmetrical skulls and lack high-frequency hearing. Here we show that protocetid and basilosaurid archaeocete skulls are distinctly and directionally asymmetrical. Archaeocete asymmetry involves curvature and axial torsion of the cranium, but no telescoping. Cranial asymmetry evolved in Eocene archaeocetes as part of a complex of traits linked to directional hearing (such as pan-bone thinning of the lower jaws, mandibular fat pads, and isolation of the ear region), probably enabling them to hear the higher sonic frequencies of sound-producing fish on which they preyed. Ultrasonic echolocation evolved in Oligocene odontocetes, enabling them to find silent prey. Asymmetry and much of the sonic-frequency range of directional hearing were lost in Oligocene mysticetes during the shift to low-frequency hearing and bulk-straining predation.
Estrogen receptor α AF-2 mutation results in antagonist reversal and reveals tissue selective function of estrogen receptor modulators
Authors: Arao Yukitomo , Hamilton Katherine J. , Ray Manas K. , Scott Gregory , Mishina Yuji , Korach Kenneth S.
Published: August 2011

The estrogen receptor (ER) is a ligand-dependent transcription factor containing two transcriptional activation domains. AF-1 is in the N terminus of the receptor protein and AF-2 activity is dependent on helix 12 of the C-terminal ligand-binding domain. Two point mutations of leucines 543 and 544 to alanines (L543A, L544A) in helix 12 minimized estrogen-dependent transcriptional activation and reversed the activity of the estrogen antagonists ICI182780 (ICI) and tamoxifen (TAM) into agonists in a similar manner that TAM activated WT ERα through AF-1 activation. To evaluate the physiological role of AF-1 and AF-2 for the tissue-selective function of TAM, we generated an AF-2–mutated ERα knock-in (AF2ERKI) mouse model. AF2ERKI homozygote female mice have hypoplastic uterine tissue and rudimentary mammary glands similar to ERα-KO mice. Female mice were infertile as a result of anovulation from hemorrhagic cystic ovaries and elevated serum LH and E2 levels, although the mutant ERα protein is expressed in the AF2ERKI model. The AF2ERKI phenotype suggests that AF-1 is not activated independently, even with high serum E2 levels. ICI and TAM induced uterotropic and ER-mediated gene responses in ovariectomized AF2ERKI female mice in the same manner as in TAM- and E2-treated WT mice. In contrast, ICI and TAM did not act as agonists to regulate negative feedback of serum LH or stimulate pituitary prolactin gene expression in a different manner than TAM- or E2-treated WT mice. The functionality of the mutant ERα in the pituitary appears to be different from that in the uterus, indicating that ERα uses AF-1 differently in the uterus and the pituitary for TAM action.
Optical imaging in galagos reveals parietal–frontal circuits underlying motor behavior
Authors: Stepniewska Iwona , Friedman Robert M. , Gharbawie Omar A. , Cerkevich Christina M. , Roe Anna W. , Kaas Jon H.
Published: August 2011

The posterior parietal cortex (PPC) of monkeys and prosimian galagos contains a number of subregions where complex, behaviorally meaningful movements, such as reaching, grasping, and body defense, can be evoked by electrical stimulation with long trains of electrical pulses through microelectrodes. Shorter trains of pulses evoke no or simple movements. One possibility for the difference in effectiveness of intracortical microstimulation is that long trains activate much larger regions of the brain. Here, we show that long-train stimulation of PPC does not activate widespread regions of frontal motor and premotor cortex but instead, produces focal, somatotopically appropriate activations of frontal motor and premotor cortex. Shorter stimulation trains activate the same frontal foci but less strongly, showing that longer stimulus trains do not produce less specification. Because the activated sites in frontal cortex correspond to the locations of direct parietal–frontal anatomical connections from the stimulated PPC subregions, the results show the usefulness of optical imaging in conjunction with electrical stimulation in showing functional pathways between nodes in behavior-specific cortical networks. Thus, long-train stimulation is effective in evoking ethologically relevant sequences of movements by activating nodes in a cortical network for a behaviorally relevant period rather than spreading activation in a nonspecific manner.
Nuclear receptor chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII) modulates mesenchymal cell commitment and differentiation
Authors: Xie Xin , Qin Jun , Lin Sue-Hwa , Tsai Sophia Y. , Tsai Ming-Jer
Published: August 2011

The mesenchymal cell is a multipotent stem cell with the capacity to give rise to multiple cell types such as adipocytes, osteoblasts, chondrocytes, and myocytes. However, the molecular events responsible for their lineage specification and differentiation remain obscure. Here we show that inactivation of chicken ovalbumin upstream promoter-transcription factor II (COUP-TFII), a member of the nuclear receptor superfamily, in mesenchymal progenitors favors osteoblast and myoblast development while simultaneously impairing adipogenic and chondrogenic programs. During mouse embryogenesis, COUP-TFII protein is highly detected in the mesenchymal compartment and is involved in mesoderm tissue formation. Ablation of COUP-TFII in mice led to higher bone density, increased muscle mass, and suppression of cartilage and fat formation. We further demonstrate that COUP-TFII directs the plasticity of mesenchymal precursors primarily through the combined modulation of Wnt signaling, Runx2 activity, as well as PPARγ and Sox9 expression. Together, our results provide insight into the mechanisms whereby a single nuclear receptor can fine-tune the lineage-specific differentiation of a progenitor cell.
Drosophila
Inducer of MEiosis 4 (IME4) is required for Notch signaling during oogenesis
Authors: Hongay Cintia F. , Orr-Weaver Terry L.
Published: August 2011

N
6
-methyladenosine is a nonediting RNA modification found in mRNA of all eukaryotes, from yeast to humans. Although the functional significance of N
6
-methyladenosine is unknown, the
Inducer of MEiosis 4
(
IME4
) gene of
Saccharomyces cerevisiae
, which encodes the enzyme that catalyzes this modification, is required for gametogenesis. Here we find that the
Drosophila IME4
homolog,
Dm ime4
, is expressed in ovaries and testes, indicating an evolutionarily conserved function for this enzyme in gametogenesis. In contrast to yeast, but as in
Arabidopsis
,
Dm ime4
is essential for viability. Lethality is rescued fully by a wild-type transgenic copy of
Dm ime4
but not by introducing mutations shown to abrogate the catalytic activity of yeast Ime4, indicating functional conservation of the catalytic domain. The phenotypes of hypomorphic alleles of
Dm ime4
that allow recovery of viable adults reveal critical functions for this gene in oogenesis. Ovarioles from
Dm ime4
mutants have fused egg chambers with follicle-cell defects similar to those observed when Notch signaling is defective. Indeed, using a reporter for Notch activation, we find markedly reduced levels of Notch signaling in follicle cells of
Dm ime4
mutants. This phenotype of
Dm ime4
mutants is rescued by inducing expression of a constitutively activated form of Notch. Our study reveals the function of IME4 in a metazoan. In yeast, this enzyme is responsible for a crucial developmental decision, whereas in
Drosophila
it appears to target the conserved Notch signaling pathway, which regulates many vital aspects of metazoan development.
Concerted action of two avirulent spore effectors activates
Reaction to Puccinia graminis 1
(
Rpg1
)
-
mediated cereal stem rust resistance
Authors: Nirmala Jayaveeramuthu , Drader Tom , Lawrence Paulraj K. , Yin Chuntao , Hulbert Scot , Steber Camille M. , Steffenson Brian J. , Szabo Les J. , von Wettstein Diter , Kleinhofs Andris
Published: August 2011

The barley stem rust resistance gene
Reaction to Puccinia graminis 1
(
Rpg1
), encoding a receptor-like kinase, confers durable resistance to the stem rust pathogen
Puccinia graminis
f. sp.
tritici
. The fungal urediniospores form adhesion structures with the leaf epidermal cells within 1 h of inoculation, followed by hyphae and haustorium formation. The RPG1 protein is constitutively expressed and not phosphorylated. On inoculation with avirulent urediniospores, it is phosphorylated in vivo within 5 min and subsequently degraded. Application of arginine-glycine-aspartic acid peptide loops prevented the formation of adhesion structures for spore attachment, the phosphorylation of RPG1, and germination of the viable spores. Arginine-glycine-aspartic acid affinity chromatography of proteins from the ungerminated avirulent rust spores led to the purification and identification of a protein with fibronectin type III and breast cancer type 1 susceptibility protein domains and a vacuolar protein sorting-associated protein 9 with a coupling of ubiquitin to endoplasmic reticulum degradation domain. Both proteins are required to induce in vivo phosphorylation and degradation of RPG1. Combined application of both proteins caused hypersensitive reaction on the stem rust-resistant cultivar Morex but not on the susceptible cultivar Steptoe. Expression studies indicated that mRNA of both genes are present in ungerminated urediniospores and are constitutively transcribed in sporelings, infected leaves, and haustoria in the investigated avirulent races. Evidence is presented that RPG1, in yeast, interacts with the two protein effectors from the urediniospores that activate cooperatively the stem rust resistance protein RPG1 long before haustoria formation.
Transcriptional programs in transient embryonic zones of the cerebral cortex defined by high-resolution mRNA sequencing
Authors: Ayoub Albert E. , Oh Sunghee , Xie Yanhua , Leng Jing , Cotney Justin , Dominguez Martin H. , Noonan James P. , Rakic Pasko
Published: August 2011

Characterizing the genetic programs that specify development and evolution of the cerebral cortex is a central challenge in neuroscience. Stem cells in the transient embryonic ventricular and subventricular zones generate neurons that migrate across the intermediate zone to the overlying cortical plate, where they differentiate and form the neocortex. It is clear that not one but a multitude of molecular pathways are necessary to progress through each cellular milestone, yet the underlying transcriptional programs remain unknown. Here, we apply differential transcriptome analysis on microscopically isolated cell populations, to define five transcriptional programs that represent each transient embryonic zone and the progression between these zones. The five transcriptional programs contain largely uncharacterized genes in addition to transcripts necessary for stem cell maintenance, neurogenesis, migration, and differentiation. Additionally, we found intergenic transcriptionally active regions that possibly encode unique zone-specific transcripts. Finally, we present a high-resolution transcriptome map of transient zones in the embryonic mouse forebrain.
Transcription factor AP4 modulates reversible and epigenetic silencing of the
Cd4
gene
Authors: Egawa Takeshi , Littman Dan R.
Published: August 2011

CD4 coreceptor expression is negatively regulated through activity of the
Cd4
silencer in CD4
–
CD8
–
double-negative (DN) thymocytes and CD8
+
cytotoxic lineage T cells. Whereas
Cd4
silencing is reversed during transition from DN to CD4
+
CD8
+
double-positive stages, it is maintained through heritable epigenetic processes following its establishment in mature CD8
+
T cells. We previously demonstrated that the Runx family of transcription factors is required for
Cd4
silencing both in DN thymocytes and CD8
+
T cells. However, additional factors that cooperate with Runx proteins in the process of
Cd4
silencing remain unknown. To identify collaborating factors, we used microarray and RNAi-based approaches and found the basic helix–loop–helix ZIP transcription factor AP4 to have an important role in
Cd4
regulation. AP4 interacts with Runx1 in cells in which
Cd4
is silenced, and is required for
Cd4
silencing in immature DN thymocytes through binding to the proximal enhancer. Furthermore, although AP4-deficient CD8
+
T cells appeared to normally down-regulate CD4 expression, AP4 deficiency significantly increased the frequency of CD4-expressing effector/memory CD8
+
T cells in mice harboring point mutations in the
Cd4
silencer. Our results suggest that AP4 contributes to
Cd4
silencing both in DN and CD8
+
T cells by enforcing checkpoints for appropriate timing of CD4 expression and its epigenetic silencing.
Ten-Eleven-Translocation 2 (TET2) negatively regulates homeostasis and differentiation of hematopoietic stem cells in mice
Authors: Ko Myunggon , Bandukwala Hozefa S. , An Jungeun , Lamperti Edward D. , Thompson Elizabeth C. , Hastie Ryan , Tsangaratou Angeliki , Rajewsky Klaus , Koralov Sergei B. , Rao Anjana
Published: August 2011

The
Ten-Eleven-Translocation 2
(
TET2
) gene encodes a member of TET family enzymes that alters the epigenetic status of DNA by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). Somatic loss-of-function mutations of
TET2
are frequently observed in patients with diverse myeloid malignancies, including myelodysplastic syndromes, myeloproliferative neoplasms, and chronic myelomonocytic leukemia. By analyzing mice with targeted disruption of the
Tet2
catalytic domain, we show here that Tet2 is a critical regulator of self-renewal and differentiation of hematopoietic stem cells (HSCs).
Tet2
deficiency led to decreased genomic levels of 5hmC and augmented the size of the hematopoietic stem/progenitor cell pool in a cell-autonomous manner. In competitive transplantation assays,
Tet2
-deficient HSCs were capable of multilineage reconstitution and possessed a competitive advantage over wild-type HSCs, resulting in enhanced hematopoiesis into both lymphoid and myeloid lineages. In vitro,
Tet2
deficiency delayed HSC differentiation and skewed development toward the monocyte/macrophage lineage. Our data indicate that Tet2 has a critical role in regulating the expansion and function of HSCs, presumably by controlling 5hmC levels at genes important for the self-renewal, proliferation, and differentiation of HSCs.
Internal and external factors in the child L2 development of the German determiner phrase
Authors: Hopp Holger
Published: August 2011

This paper studies the development of the German determiner phrase (DP) in 60 child second-language (L2) learners of German between the ages of 3;5 and 7;0. We consider case and gender marking as well as gender concord and test for effects of internal (age, age of onset) and external (length of exposure) factors. Further, developmental patterns are compared between child L1 and L2 acquisition. The results show no contingency of child L2 performance and age factors, yet strong correlations with length of exposure. Like child L1 acquirers, child L2 learners are found to proceed through similar developmental stages, and they establish lexical gender distinctions before syntactic case distinctions in inflection. These findings are discussed in the context of current generative approaches and the role of age in child and adult L2 acquisition.
The production and processing of determiner–noun agreement in child L2 Dutch
Authors: Blom Elma , Vasić Nada
Published: August 2011

Recent research has shown that children who learn Dutch as their second language (L2) have difficulties with Dutch grammatical gender. This study shows that six to nine year old L2 Dutch children whose first language (L1) is Turkish noticed incorrect gender agreement between determiner and noun only if gender was marked on the noun. The L1 Turkish L2 Dutch children made more errors with determiner-noun agreement than monolingual L1 controls with matching language abilities. Unlike monolingual controls, L2 children’s accuracy with determiner-noun agreement was not facilitated by word frequency and vocabulary size. Children in both groups made fewer errors with neuter nouns if a cue on the noun marked a noun’s gender. We conclude that there is an asymmetry between L2 children’s processing and production of determiner-noun agreement, that grammatical gender develops gradually and that L2 children’s delay is rather caused by external factors related to a heterogeneous language environment than by internal factors.
Formulaic jokes in interaction
Authors: Bird Christy
Published: August 2011

While both humor and prosody in interaction have received scholarly attention in recent years, the prosody of humor has not been extensively explored. This study begins to fill this gap by investigating whether prosodic cues can be identified for riddles told in interaction, focusing on wh-questions in riddles versus ordinary conversation. The analysis demonstrates that in comparison to conversational wh-questions, riddles have less pitch variation both within the utterance and at the syllable level. It is argued that riddles do not contain such wide pitch excursions because they do not require contextual disambiguation. While this study provides no evidence that riddles must be prosodically packaged in a specific way, the analysis suggests that the pitch of riddles is constrained due to interactional context. This constrained pitch is argued to work in conjunction with the formulaic syntax and content of riddle questions to signal to hearers that a joke is being told.
Verbal irony in the wild
Authors: Bryant Gregory A.
Published: August 2011

Verbal irony constitutes a rough class of indirect intentional communication involving a complex interaction of language-specific and communication-general phenomena. Conversationalists use verbal irony in conjunction with paralinguistic signals such as speech prosody. Researchers examining acoustic features of speech communication usually focus on how prosodic information relates to the surface structure of utterances, and often ignore prosodic phenomena associated with implied meaning. In the case of verbal irony, there exists some debate concerning how these prosodic features manifest themselves in conversation. A form-function approach can provide a valuable tool for understanding speakers’ varied vocal strategies in this domain. Here I describe several ways conversationalists employ prosodic contrasts, laughter, and other speech characteristics in their attempts to communicate effectively and efficiently. The presented examples, culled from spontaneous conversation recordings, reveal just a small sample of the enormous variation in delivery styles speakers adopt when communicating with ironic language.
Does prosody play a specific role in conversational humor?
Authors: Bertrand Roxane , Priego-Valverde Béatrice
Published: August 2011

In this paper we use Conversation Analysis (CA) to investigate conversational humor in talk-in-interaction. We attempt to better understand how the latter is produced and co-constructed by participants in accounting for the devices used by participants in their sequential environment. The framework of CA enables us to take into account the various means available to speakers to communicate, orient to the others, etc. From our data, reported speech, confirmation request/answer, and repetitions appear as the main discursive devices to create humor (presented as the result of the appearance of the incongruity). We focused on prosodic cues that are strongly involved in these devices and then contribute to the humorous tonality of the talk. Finally, the co-construction of conversational humor is mainly described through the notion of orientation and prosodic orientation.
MAPPING THE ACTIVISM OF ETHNIC AND NATIONAL MINORITIES IN POLAND
Authors: Jasiewicz Joanna
Published: August 2011

For more than 40 years, minorities in Poland were deprived of the opportunity to publicly voice their demands and explicitly address mounting concerns over ethnic problems. For several decades, the ethnic presence in the public arena was restricted to a folkloric and apolitical façade. This article demonstrates that the tide of change brought about by the momentous year of 1989 has opened novel opportunities for minority groups. The article's objectives are twofold. First, it examines the boundaries of the national discursive structure in the minority rights area in Poland demonstrating that it is deeply embedded in Poland's history. Second, it explores the identity of actors who contributed to the debate in the field of ethnic politics in Poland and reveals that ethnic groups and state representatives are the most active players in the game when the regulation of minorities’ social and political position in contemporary Poland is at stake. The article shows that using minority language as an auxiliary one in contacts with public authorities and the issue of topographic double-naming are major sources of political contention. On the other hand, it reveals that minorities address these topics by pushing for more rights in the contentious area of the auxiliary function of ethnic languages.
Representation of squares by monic second degree polynomials in the field of 𝑝-adic meromorphic functions
Authors: Pasten Hector
Published: August 2011

We prove a result on the representation of squares by monic second degree polynomials in the field ofpp-adic meromorphic functions in order to solve positively Büchi’snnsquares problem in this field. Using this result, we prove the non-existence of an algorithm to decide whether a system of diagonal quadratic forms overZ[z]\mathbb {Z}[z]represents or not in the ring ofpp-adic entire functions (in the variablezz) a given vector of polynomials inZ[z]\mathbb {Z}[z], and a similar result forpp-adic meromorphic functions when the systems allow vanishing conditions on the unknowns. This improves the known negative answers for the analogue of Hilbert’s Tenth Problem for these structures. We also improve some results by Vojta concerning the case of complex meromorphic functions, the case of function fields and finally the case of number fields, and we show an intimate relation of the latter with Bombieri’s Conjecture for surfaces over number fields.
Do Shocks Change Organizations? The Case of NASA
Authors: Donahue Amy K. , O'Leary Rosemary
Published: August 2011

The 50-year history of the National Aeronautics and Space Administration's (NASA) spaceflight program is marked by spectacular accomplishments and devastating tragedy. NASA has suffered three major disasters, each of which destroyed a spacecraft and killed its crew. In the wake of each accident, investigators and analysts identified causes and recommended technical and organizational improvements that NASA should undertake. The NASA case presents an opportunity to examine the question: Do shocks change organizations? The article reviews three prominent theoretical models of organizational change. Then, using data derived from 5 years of participant observation, as well as government reports, academic investigations, and news articles, we present an analysis of whether the factors required for change identified in the literature were and are present at NASA. The results of this examination suggest that in the wake of these shocks, the agency undertook many technical and procedural changes, but that, as the literature predicts, there are also barriers embedded in the fabric of the agency that are likely to thwart change. We conclude by examining the prospects for understanding change in public, private, and nonprofit organizations of all sizes that experience shocks and offer propositions for future research.
Coagulation and fibrinolytic disturbances are related to carotid intima thickness and arterial blood pressure in Turner syndrome
Authors: Gravholt Claus H. , Mortensen Kristian H. , Andersen Niels H. , Ibsen Liselotte , Ingerslev Jørgen , Hjerrild Britta E.
Published: August 2011

Objective  Turner syndrome (TS) is characterized by growth retardation, hypogonadism and a high risk of cardiovascular complications and atherosclerosis; case reports suggest that thrombo‐embolic complications may be present.

Design  Cross‐sectional study.

Patients  Sixty women with TS.

Measurements  We characterized the activities of the haemostatic system, elucidated by the assessment of a panel of clotting factors and thrombosis risk factors and related these findings to carotid intima thickness (CIMT) and blood pressure.

Results  Most (81%) received hormone replacement therapy. The medians of all measured factors and inflammatory parameters were not different from normative data, but many cases displayed values of C‐reactive protein (CRP) (40%), fibrinogen (15%), fibrin D‐dimer (15%), factor VIII (25%), von Willebrand factor (vWF) (15%), cholesterol and liver parameters that were greater than normative limits. CRP, fibrinogen, vWF, factor VIII and liver parameters were highly and positively correlated. Haemostatic variables were positively related to both CIMT and blood pressure. The Factor V Leiden G1691A gene polymorphism heterozygosity was detected in 12·5%.

Conclusion  We describe a significant proportion of individual TS females having high levels of vWF, factor VIII, fibrinogen and CRP (15–40%) and an increased frequency of the Leiden mutation, with important associations with CIMT and blood pressure, suggesting that a subset of TS may have an unfavourable haemostatic balance, which may contribute to the increased risk of premature ischaemic heart disease and possibly increase the risk of deep venous and portal vein thrombosis.
Termination of Vibrio cholerae virulence gene expression is mediated by proteolysis of the major virulence activator, ToxT
Authors: Abuaita Basel H. , Withey Jeffrey H.
Published: August 2011

Vibrio cholerae is the causative agent of cholera, a severe diarrhoeal illness. V. cholerae produces two major virulence factors: the cholera toxin, which directly causes diarrhoea, and the toxin‐coregulated pilus, which is required for intestinal colonization. Production of these virulence factors is dependent on the major virulence regulator, ToxT. Under virulence‐inducing growth conditions, transcription factors ToxR and TcpP initially activate transcription of toxT. However, once ToxT has been expressed, it produces more of itself independent of ToxR and TcpP by activating transcription of the long tcpA operon, within which toxT is located. It is known that V. cholerae terminates virulence gene expression prior to escape from the host, but it is unknown how this ToxT‐positive feedback loop is broken, an essential step in terminating virulence gene expression. To better understand how ToxT protein activity is regulated, we monitored ToxT accumulation and activity under virulence‐inducing and ‐repressing growth conditions. Our results suggest that ToxT protein undergoes proteolytic degradation to terminate virulence gene expression. This directed degradation of ToxT supports a model for terminating V. cholerae virulence gene expression late in infection, with both ToxT and TcpP undergoing proteolysis prior to escape from the host.
Skin rejuvenating effects of chemical peeling: a study in photoaged hairless mice
Authors: Han Sung Hyup , Kim Hong Jig , Kim Si Yong , Kim You Chan , Choi Gwang Seong , Shin Jeong Hyun
Published: August 2011

Background  Chemical peeling is a dermatologic treatment for skin aging. However, the mechanism by which the chemical peel achieves its results is not clear. We investigated the effects of chemical peeling and the mechanism of wrinkle reduction in photoaged hairless mice skin.

Methods  After inducing photoaged skin in hairless mice by repetitive ultraviolet‐B irradiation applied over 14 weeks, we applied trichloroacetic acid (TCA) 30%, TCA 50%, and phenol on areas of the same size on the backs of the mice. Punch biopsies were obtained 7, 14, 28, and 60 days after the procedure for histologic and immunohistochemical analyses.

Results  Histologic examination showed an increase in dermal thickness, collagen fibers, and elastic fibers in the dermis of intervention groups compared with control groups. These increases were maintained significantly for 60 days.

Conclusions  This study demonstrates that chemical peeling reduces wrinkles and regenerates skin by increasing dermal thickness and the amount of collagen and elastic fibers in photoaged skin.
Pregnancy outcome in women with vitiligo
Authors: Horev Amir , Weintraub Adi Y. , Sergienko Ruslan , Wiznitzer Arnon , Halevy Sima , Sheiner Eyal
Published: August 2011

Background  Vitiligo, characterized by destruction of melanocytes, causes a patchy depigmentation of the skin. It has been hypothesized to have an autoimmune pathogenesis. Autoimmune disorders are more common among women and may be associated with adverse pregnancy outcomes, such as recurrent abortions, intrauterine growth restriction (IUGR), and pre‐eclampsia.

Objective  The purpose of this study was to investigate whether patients with vitiligo have increased rates of gestational complications.

Methods  A retrospective comparative study was undertaken comparing pregnancy complications of patients with and without vitiligo. The population was composed of all singleton deliveries that occurred at the Soroka University Medical Center in Israel during the years 1988–2006. Women lacking prenatal care and multiple gestations were excluded from the study. A multivariable logistic regression model was constructed to control for confounders.

Results  Of 186,222 singleton deliveries, 79 (0.04%) were patients with vitiligo. Vitiligo was not found to be associated with adverse pregnancy outcomes, including obstetric risk factors, labor characteristics and complications, and birth outcome. Using multivariable analysis, only grand multiparity (above five deliveries) was independently associated with vitiligo (OR = 2.01; 95% CI 1.2–3.2; P = 0.007).

Limitations  Retrospective analysis was a limitation.

Conclusion  Vitiligo is not associated with adverse pregnancy outcomes. Accordingly, patients with vitiligo should not be managed differently from the general obstetric population.
Treatment of reticulated acropigmentation of Kitamura with Q‐switched alexandrite laser
Authors: Fahad Al Saif , Al Shahwan Hissah , Dayel Salman Bin
Published: August 2011

Background  Reticulated acropigmentation of Kitamura (RAPK) is a pigmentary disorder of autosomal dominant inheritance, occurring predominantly within the Japanese population, for which no successful treatment has been described.

Objective  The objective was to describe a 23‐year‐old Saudi woman with reticulated acropigmentation of Kitamura (RAPK), who was successfully treated with a 75‐nm Q‐switched alexandrite laser.

Method  To report a 23‐year‐old Saudi woman with reticulated acropigmentation of kitamura (RAPK) who was treated with two sessions of the Q‐switched alexandrite laser, six weeks apart with no recurrence after two years.

Results  Cutaneous pigmentation of reticulated acropigmentation of kitamura (RAPK) almost resolved completely in two laser sessions. Side effects were limited to transient post inflammatory hypopigmentation.

Conclusion  Cutaneous pigmentation of reticulated acropigmentation of kitamura (RAPK) can be effectively treated by Q‐switched alexandrite (755‐nm) laser, which shows a promising result, and it can be considered as treatment option, although further studies are required to confirm the effectiveness of this treatment modality with other Q‐switched laser; e.g. Q‐switched ND:YAG or Q‐switch Ruby.
New topics in bradykinin research
Authors: Maurer M. , Bader M. , Bas M. , Bossi F. , Cicardi M. , Cugno M. , Howarth P. , Kaplan A. , Kojda G. , Leeb‐Lundberg F. , Lötvall J. , Magerl M.
Published: August 2011

To cite this article: Maurer M, Bader M, Bas M, Bossi F, Cicardi M, Cugno M, Howarth P, Kaplan A, Kojda G, Leeb‐Lundberg F, Lötvall J, Magerl M. New topics in bradykinin research. Allergy 2011; 66: 1397–1406.

Bradykinin has been implicated to contribute to allergic inflammation and the pathogenesis of allergic conditions. It binds to endothelial B1 and B2 receptors and exerts potent pharmacological and physiological effects, notably, decreased blood pressure, increased vascular permeability and the promotion of classical symptoms of inflammation such as vasodilation, hyperthermia, oedema and pain. Towards potential clinical benefit, bradykinin has also been shown to exert potent antithrombogenic, antiproliferative and antifibrogenic effects. The development of pharmacologically active substances, such as bradykinin receptor blockers, opens up new therapeutic options that require further research into bradykinin. This review presents current understanding surrounding the role of bradykinin in nonallergic angioedema and other conditions seen by allergists and emergency physicians, and its potential role as a therapeutic target.
Reconstructing savanna tree cover from pollen, phytoliths and stable carbon isotopes
Authors: Aleman Julie , Leys Bérangère , Apema Roger , Bentaleb Ilham , Dubois Marc A. , Lamba Barthélémy , Lebamba Judicaël , Martin Céline , Ngomanda Alfred , Truc Loïc , Yangakola Jean‐Michel , Favier Charly , Bremond Laurent
Published: August 2011

Aim

To calibrate a model of the relationship between bio‐proxies (pollen, phytoliths and δ13C of soil organic matter) and woody cover, measured as the leaf area index (LAI). This relationship, applied in palaeosequences, enables reconstruction of past savanna tree cover.

Location

The samples are from tropical Africa. Modern soil samples are from the Central African Republic and past samples are from sediments of lakes in Senegal and Congo.

Methods

We analysed the pollen and phytolith content and stable carbon isotope values of 17 soil samples taken from three short transects in the Central African Republic; LAI was measured on the same transects. The indices used were the AP/NAP ratio of arboreal (AP) to non‐arboreal (NAP) pollen, the D/P ratio of ligneous dicotyledons (D) to Poaceae (P) phytoliths, and the δ13C of soil organic matter, i.e. the 13C/12C ratio.

Results

A multi‐proxy model was calibrated. The best model included only a combination of pollen and phytolith as proxies, excluding organic matter δ13C because of its long mean residence time in the soil. The model was then applied to two palaeosequences in Africa, and a time series of relative LAI changes was obtained, providing new information about vegetation changes.

Conclusion

This model can be applied in palaeosequences to reconstruct relative time series of LAI in African savannas and can help interpret vegetation changes quantitatively. This approach is complementary to the description of pollen and phytolith assemblages.
Shape Factors of Cylindrical Piezometers in Uniform Soil
Authors: Silvestri Vincenzo , Abou‐Samra Ghassan , Bravo‐Jonard Christian
Published: August 2011

This article presents the analytical solution of Laplace equation for the steady flow around open‐ended cylindrical piezometers located in an infinite, isotropic, and incompressible saturated soil. Shape factors are obtained for piezometers with varying length‐to‐diameter ratios. Comparisons are made with published factors obtained by means of approximate analytical solutions, numerical approaches, and measurements in electric analog models. It is shown that some expressions that are currently used in practice are inadequate and should be abandoned.
Cannabinoids attenuate hippocampal gamma oscillations by suppressing excitatory synaptic input onto CA3 pyramidal neurons and fast spiking basket cells
Authors: Holderith Noémi , Németh Beáta , Papp Orsolya I. , Veres Judit M. , Nagy Gergő A. , Hájos Norbert
Published: August 2011

Non‐Technical Summary  Administration of cannabinoids can impair several cognitive functions, including memory by altering synchronous activities in cortical networks. We show that the gamma frequency (40 Hz) oscillations in hippocampal slices, that are prominent oscillations in electroencephalogram during awake states in vivo, are reduced by cannabinoids. This effect can be explained by the suppression of the excitatory synaptic transmission onto fast spiking basket cells, GABAergic cells that are key players in oscillogenesis. The reduced excitatory drive onto these interneurons leads to a reduction in neuronal firing frequency and precision, and thus to smaller field potentials. Our data further our understanding of the synaptic mechanisms of how cannabinoids alter neuronal operation.
Purinergic signalling mobilizes mitochondrial Ca2+ in mouse Sertoli cells
Authors: Veitinger Sophie , Veitinger Thomas , Cainarca Silvia , Fluegge Daniela , Engelhardt Corinna H. , Lohmer Stefan , Hatt Hanns , Corazza Sabrina , Spehr Jennifer , Neuhaus Eva M. , Spehr Marc
Published: August 2011

Non‐Technical Summary  In mammalian testes, Sertoli cells play a key physiological role in germ cell development. Previous research has implicated local ATP release as a potential mechanism of Sertoli cell stimulation. We show that, in mouse Sertoli cells, two different receptor proteins are activated by ATP. Receptor activation, in turn, causes elevation of calcium ion levels inside the cells. By using a novel method to visualize such calcium signals, we identify mitochondria as essential elements of calcium regulation in the testis.
Computational Fluid Dynamics Analysis of Cooling Tower Inlets
Authors: Reuter H. C. R. , Kröger D. G.
Published: August 2011

Cooling tower inlet losses are the flow losses or viscous dissipation of mechanical energy affected directly by the cooling tower inlet design, which according to the counterflow natural draft wet-cooling tower performance analysis example given in Kröger (Kröger, 2004, Air-Cooled Heat Exchangers and Cooling Towers: Thermal-Flow Performance Evaluation, Pennwell Corp., Tulsa, OK), can be more than 20% of the total cooling tower flow losses. Flow separation at the lower edge of the shell results in a vena contracta with a distorted inlet velocity distribution that causes a reduction in effective fill or heat exchanger flow area. In this paper, a two-dimensional (axi-symmetric) computational fluid dynamic (CFD) model is developed using the commercial CFD code ANSYS FLUENT, to simulate the flow patterns, loss coefficients and effective flow diameter of circular natural draft cooling tower inlets under windless conditions. The CFD results are compared with axial velocity profile data, tower inlet loss coefficients and effective diameters determined experimentally by Terblanche (Terblanche, 1993, “Inlaatverliese by Koeltorings,” M. Sc. Eng. thesis, Stellenbosch University, Stellenbosch, South Africa) on a cylindrical scale sector model as well as applicable empirical relations found in Kröger, determined using the same experimental apparatus as Terblanche. The validated CFD model is used to investigate the effects of Reynolds number, shell-wall thickness, shell wall inclination angle, fill loss coefficient, fill type, inlet diameter to inlet height ratio and inlet geometry on the flow patterns, inlet loss coefficient and effective diameter of full-scale cooling towers. Ultimately, simple correlations are proposed for determining the cooling tower inlet loss coefficient and inlet effective flow diameter ratio of full-scale cooling towers excluding the effect of rain zones and the structural supports around the cooling tower entrance.