bluuebunny/crossref_metadata_2025 huggingface dataset:
Suppression of leukemia development caused by PTEN loss
Authors: Guo Wei , Schubbert Suzanne , Chen James Y. , Valamehr Bahram , Mosessian Sherly , Shi Hubing , Dang Nhi H. , Garcia Consuelo , Theodoro Mariana F. , Varella-Garcia Marileila , Wu Hong
Published: January 2011

Multiple genetic or molecular alterations are known to be associated with cancer stem cell formation and cancer development. Targeting such alterations, therefore, may lead to cancer prevention. By crossing our previously established
phosphatase and tensin homolog (Pten)
-
null acute T-lymphoblastic leukemia (T-ALL) model onto the
recombination-activating gene 1
−/−
background, we show that the lack of variable, diversity and joining [V(D)J] recombination completely abolishes the
Tcrα/δ-c-myc
translocation and T-ALL development, regardless of β-catenin activation. We identify mammalian target of rapamycin (mTOR) as a regulator of β-selection. Rapamycin, an mTOR-specific inhibitor, alters nutrient sensing and blocks T-cell differentiation from CD4
−
CD8
−
to CD4
+
CD8
+
, the stage where the
Tcrα/δ-c-myc
translocation occurs. Long-term rapamycin treatment of preleukemic
Pten
-null mice prevents
Tcrα/δ-c-myc
translocation and leukemia stem cell (LSC) formation, and it halts T-ALL development. However, rapamycin alone fails to inhibit mTOR signaling in the c-Kit
mid
CD3
+
Lin
−
population enriched for LSCs and eliminate these cells. Our results support the idea that preventing LSC formation and selectively targeting LSCs are promising approaches for antileukemia therapies.
Is there brief temporal buffering of successive visual inputs?
Authors: Smith Wayne S. , Mollon J. D. , Bhardwaj Rishi , Smithson Hannah E.
Published: January 2011

The part-report advantage has been used to identify short-lived forms of visual storage (Sperling, 1960). We adopt the part-report paradigm to test whether visual memory can preserve, for a brief time, successive inputs and their temporal order. In our experiments, two successive arrays, each of 4 digits, were presented on each trial. The two arrays were spatially coincident, and each was followed by a random pattern-mask. In the part-report conditions, an auditory cue indicated whether the participant should report the first array or the second array. The results consistently showed a part-report advantage, which ranged in size from 16% to 37%. Delaying the cue by 500 ms abolished most of this advantage, in that performance was then similar to that in whole-report conditions. Subsequent experiments confirmed that the part-report superiority we measure is not achieved by (a) making eye movements that spatially displace the second array relative to the first; (b) extracting information from a single snapshot containing an integrated representation of the targets and masks; or (c) transferring a subset of material to a phonological store. We propose instead that observers have access to a limited, rapidly decaying representation of successive visual inputs stored in temporal sequence.
Do Common Systems Control Eye Movements and Motion Extrapolation?
Authors: Makin Alexis D.J. , Poliakoff Ellen
Published: January 2011

People are able to judge the current position of occluded moving objects. This operation is known as motion extrapolation. It has previously been suggested that motion extrapolation is independent of the oculomotor system. Here we revisited this question by measuring eye position while participants completed two types of motion extrapolation task. In one task, a moving visual target travelled rightwards, disappeared, then reappeared further along its trajectory. Participants discriminated correct reappearance times from incorrect (too early or too late) with a two-alternative forced-choice button press. In the second task, the target travelled rightwards behind a visible, rectangular occluder, and participants pressed a button at the time when they judged it should reappear. In both tasks, performance was significantly different under fixation as compared to free eye movement conditions. When eye movements were permitted, eye movements during occlusion were related to participants' judgements. Finally, even when participants were required to fixate, small changes in eye position around fixation (<2°) were influenced by occluded target motion. These results all indicate that overlapping systems control eye movements and judgements on motion extrapolation tasks. This has implications for understanding the mechanism underlying motion extrapolation.
A characterization of the singular time of the mean curvature flow
Authors: Cooper Andrew
Published: January 2011

In this note we investigate the behaviour at finite-time singularities of the mean curvature flow of compact Riemannian submanifolds

M
t
m

↪
(

N

m
+
n

,
h
)

M_t^m\hookrightarrow (N^{m+n},h)

. We show that they are characterized by the blow-up of a trace

A
=
H
⋅
II

A=H\cdot \operatorname {II}

of the square of the second fundamental form.
Foregoing Sub‐therapeutic Antibiotics: the Impact on Broiler Grow‐out Operations
Authors: MacDonald James M. , Wang Sun‐Ling
Published: January 2011

We use data from a recent national survey to analyze the use of sub‐therapeutic antibiotics (STAs) among broiler growers. We estimate that 42% of growers do not use STAs in their feed or water, and instead rely on a set of other practices, including pathogen testing, expanded sanitary protocols, altered feeding regimens, and Hazard Analysis and Critical Control Point HACCP plans to maintain production. Suspending STAs has no statistically significant impact on production given other inputs, but producers who forego STAs receive higher contract fees, suggesting that they bear higher costs to realize a given level of output.
Eisenhower versus the Spin-off Story: Did the Rise of the Military–Industrial Complex Hurt or Help America's Commercial Aircraft Industry?
Authors: Gholz Eugene
Published: January 2011

In his Farewell Address, President Eisenhower warned that the military-industrial complex (MIC) threatened to dominate American research, crowding out commercial innovation. Ironically, a number of analysts point to spin-off benefits of the 1950s' military effort as a crucial source of American high-tech competitiveness, often citing the key example of the relationship between military jet aircraft and the Boeing's 707. But the huge military investment in jet aviation had both benefits and costs for the commercial industry. This article compares the development of the Boeing 707 and its relationship to military projects like the KC-135 tanker to the contemporary development of commercial jet aircraft by other companies that were also integral parts of the military-industrial complex (MIC), including Douglas Aircraft and its commercial DC-8 and Convair and its commercial 880 and 990. Using evidence from archives, interviews with retired company executives, contemporary trade press, and academic studies, the article concludes that membership in the MIC did not offer firms a leg up in commercial markets. President Eisenhower was generally right about the costs of the military effort, but military spending remained low enough to allow commercial industry to thrive in parallel to the defense industry.
Effect of Phosphate Salts on the Pasting Properties of Korean Instant‐Fried Noodle
Authors: Wang Li , Hou Gary G. , Hsu Ya‐Hsuan , Zhou Lirong
Published: January 2011

Up to 15% modified potato starch (MPS) is often added into Korean instant noodle formulas to improve the cooking and eating quality. However, the addition of MPS leads to higher raw material costs. The effect of phosphate salts (PS) on Korean instant‐fried noodle pasting properties was investigated in this research. When 33% of total MPS in the regular Korean instant noodle formula was substituted by a small amount of PS (≤0.3%), the results clearly indicated that all the PS improved the pasting properties of noodle dough and ground instant‐fried noodle powder, especially the peak viscosity of the Rapid ViscoAnalyser (RVA) curves. However, the pasting temperature was affected little by PS except that tripotassium phosphate increased it significantly. The RVA results showed that the pasting properties of ground instant noodle powder were significantly improved when 33% of MPS was substituted by 0.300% dipotassium phosphate. Meanwhile, the pasting properties were close to those of the regular formula ground instant noodle powder when 33% of MPS was substituted by 0.030% monosodium phosphate or 0.300% disodium phosphate. Therefore, we suggest that MPS used in Korea instant‐fried noodle could be partially substituted by the blends of selected PS.
Bacterial Effector HopF2 Suppresses Arabidopsis Innate Immunity at the Plasma Membrane
Authors: Wu Shujing , Lu Dongping , Kabbage Mehdi , Wei Hai-Lei , Swingle Bryan , Records Angela R. , Dickman Martin , He Ping , Shan Libo
Published: January 2011

Many bacterial pathogens inject a cocktail of effector proteins into host cells through type III secretion systems. These effectors act in concert to modulate host physiology and immune signaling, thereby promoting pathogenicity. In a search for additional Pseudomonas syringae effectors in suppressing plant innate immunity triggered by pathogen or microbe-associated molecular patterns (PAMPs or MAMPs), we identified P. syringae tomato DC3000 effector HopF2 as a potent suppressor of early immune-response gene transcription and mitogen-activated protein kinase (MAPK) signaling activated by multiple MAMPs, including bacterial flagellin, elongation factor Tu, peptidoglycan, lipopolysaccharide and HrpZ1 harpin, and fungal chitin. The conserved surface-exposed residues of HopF2 are essential for its MAMP suppression activity. HopF2 is targeted to the plant plasma membrane through a putative myristoylation site, and the membrane association appears to be required for its MAMP-suppression function. Expression of HopF2 in plants potently diminished the flagellin-induced phosphorylation of BIK1, a plasma membrane–associated cytoplasmic kinase that is rapidly phosphorylated within one minute upon flagellin perception. Thus, HopF2 likely intercepts MAMP signaling at the plasma membrane immediately of signal perception. Consistent with the potent suppression function of multiple MAMP signaling, expression of HopF2 in transgenic plants compromised plant nonhost immunity to bacteria P. syringae pv. Phaseolicola and plant immunity to the necrotrophic fungal pathogen Botrytis cinerea.
Inoculation- and Nitrate-Induced CLE Peptides of Soybean Control NARK-Dependent Nodule Formation
Authors: Reid Dugald E. , Ferguson Brett J. , Gresshoff Peter M.
Published: January 2011

Systemic autoregulation of nodulation in legumes involves a root-derived signal (Q) that is perceived by a CLAVATA1-like leucine-rich repeat receptor kinase (e.g. GmNARK). Perception of Q triggers the production of a shoot-derived inhibitor that prevents further nodule development. We have identified three candidate CLE peptide-encoding genes (GmRIC1, GmRIC2, and GmNIC1) in soybean (Glycine max) that respond to Bradyrhizobium japonicum inoculation or nitrate treatment. Ectopic overexpression of all three CLE peptide genes in transgenic roots inhibited nodulation in a GmNARK-dependent manner. The peptides share a high degree of amino acid similarity in a 12-amino-acid C-terminal domain, deemed to represent the functional ligand of GmNARK. GmRIC1 was expressed early (12 h) in response to Bradyrhizobium-sp.-produced nodulation factor while GmRIC2 was induced later (48 to 72 h) but was more persistent during later nodule development. Neither GmRIC1 nor GmRIC2 were induced by nitrate. In contrast, GmNIC1 was strongly induced by nitrate (2 mM) treatment but not by Bradyrhizobium sp. inoculation and, unlike the other two GmCLE peptides, functioned locally to inhibit nodulation. Grafting demonstrated a requirement for root GmNARK activity for nitrate regulation of nodulation whereas Bradyrhizobium sp.-induced regulation was contingent on GmNARK function in the shoot.
Molecular Epidemiology of Plum pox virus in Japan
Authors: Maejima Kensaku , Himeno Misako , Komatsu Ken , Takinami Yusuke , Hashimoto Masayoshi , Takahashi Shuichiro , Yamaji Yasuyuki , Oshima Kenro , Namba Shigetou
Published: January 2011

For a molecular epidemiological study based on complete genome sequences, 37 Plum pox virus (PPV) isolates were collected from the Kanto region in Japan. Pair-wise analyses revealed that all 37 Japanese isolates belong to the PPV-D strain, with low genetic diversity (less than 0.8%). In phylogenetic analysis of the PPV-D strain based on complete nucleotide sequences, the relationships of the PPV-D strain were reconstructed with high resolution: at the global level, the American, Canadian, and Japanese isolates formed their own distinct monophyletic clusters, suggesting that the routes of viral entry into these countries were independent; at the local level, the actual transmission histories of PPV were precisely reconstructed with high bootstrap support. This is the first description of the molecular epidemiology of PPV based on complete genome sequences.
Disgust as an adaptive system for disease avoidance behaviour
Authors: Curtis Valerie , de Barra Mícheál , Aunger Robert
Published: January 2011

Disgust is an evolved psychological system for protecting organisms from infection through disease avoidant behaviour. This ‘behavioural immune system’, present in a diverse array of species, exhibits universal features that orchestrate hygienic behaviour in response to cues of risk of contact with pathogens. However, disgust is also a dynamic adaptive system. Individuals show variation in pathogen avoidance associated with psychological traits like having a neurotic personality, as well as a consequence of being in certain physiological states such as pregnancy or infancy. Three specialized learning mechanisms modify the disgust response: the Garcia effect, evaluative conditioning and the law of contagion. Hygiene behaviour is influenced at the group level through social learning heuristics such as ‘copy the frequent’. Finally, group hygiene is extended symbolically to cultural rules about purity and pollution, which create social separations and are enforced as manners. Cooperative hygiene endeavours such as sanitation also reduce pathogen prevalence. Our model allows us to integrate perspectives from psychology, ecology and cultural evolution with those of epidemiology and anthropology. Understanding the nature of disease avoidance psychology at all levels of human organization can inform the design of programmes to improve public health.
An evaluation of the concept of innateness
Authors: Mameli Matteo , Bateson Patrick
Published: January 2011

The concept of innateness is often used in explanations and classifications of biological and cognitive traits. But does this concept have a legitimate role to play in contemporary scientific discourse? Empirical studies and theoretical developments have revealed that simple and intuitively appealing ways of classifying traits (e.g. genetically specified versus owing to the environment) are inadequate. They have also revealed a variety of scientifically interesting ways of classifying traits each of which captures some aspect of the innate/non-innate distinction. These include things such as whether a trait is canalized, whether it has a history of natural selection, whether it developed without learning or without a specific set of environmental triggers, whether it is causally correlated with the action of certain specific genes, etc. We offer an analogy: the term ‘jade’ was once thought to refer to a single natural kind; it was then discovered that it refers to two different chemical compounds, jadeite and nephrite. In the same way, we argue, researchers should recognize that ‘innateness’ refers not to a single natural kind but to a set of (possibly related) natural kinds. When this happens, it will be easier to progress in the field of biological and cognitive sciences.
Unity and diversity in human language
Authors: Fitch W. Tecumseh
Published: January 2011

Human language is both highly diverse—different languages have different ways of achieving the same functional goals—and easily learnable. Any language allows its users to express virtually any thought they can conceptualize. These traits render human language unique in the biological world. Understanding the biological basis of language is thus both extremely challenging and fundamentally interesting. I review the literature on linguistic diversity and language universals, suggesting that an adequate notion of ‘formal universals’ provides a promising way to understand the facts of language acquisition, offering order in the face of the diversity of human languages. Formal universals are cross-linguistic generalizations, often of an abstract or implicational nature. They derive from cognitive capacities to perceive and process particular types of structures and biological constraints upon integration of the multiple systems involved in language. Such formal universals can be understood on the model of a general solution to a set of differential equations; each language is one particular solution. An explicit formal conception of human language that embraces both considerable diversity and underlying biological unity is possible, and fully compatible with modern evolutionary theory.
Endless forms: human behavioural diversity and evolved universals
Authors: Smith Eric Alden
Published: January 2011

Human populations have extraordinary capabilities for generating behavioural diversity without corresponding genetic diversity or change. These capabilities and their consequences can be grouped into three categories: strategic (or cognitive), ecological and cultural-evolutionary. Strategic aspects include: (i) a propensity to employ complex conditional strategies, some certainly genetically evolved but others owing to directed invention or to cultural evolution; (ii) situations in which fitness payoffs (or utilities) are frequency-dependent, so that there is no one best strategy; and (iii) the prevalence of multiple equilibria, with history or minor variations in starting conditions (path dependence) playing a crucial role. Ecological aspects refer to the fact that social behaviour and cultural institutions evolve in diverse niches, producing various adaptive radiations and local adaptations. Although environmental change can drive behavioural change, in humans, it is common for behavioural change (especially technological innovation) to drive environmental change (i.e. niche construction). Evolutionary aspects refer to the fact that human capacities for innovation and cultural transmission lead to diversification and cumulative cultural evolution; critical here is institutional design, in which relatively small shifts in incentive structure can produce very different aggregate outcomes. In effect, institutional design can reshape strategic games, bringing us full circle.
Parental investment and the optimization of human family size
Authors: Lawson David W. , Mace Ruth
Published: January 2011

Human reproductive behaviour is marked by exceptional variation at the population and individual level. Human behavioural ecologists propose adaptive hypotheses to explain this variation as shifting phenotypic optima in relation to local socioecological niches. Here we review evidence that variation in fertility (offspring number), in both traditional and modern industrialized populations, represents optimization of the life-history trade-off between reproductive rate and parental investment. While a reliance on correlational methods suggests the true costs of sibling resource competition are often poorly estimated, a range of anthropological and demographic studies confirm that parents balance family size against offspring success. Evidence of optimization is less forthcoming. Declines in fertility associated with modernization are particularly difficult to reconcile with adaptive models, because fertility limitation fails to enhance offspring reproductive success. Yet, considering alternative measures, we show that modern low fertility confers many advantages on offspring, which are probably transmitted to future generations. Evidence from populations that have undergone or initiated demographic transition indicate that these rewards to fertility limitation fall selectively on relatively wealthy individuals. The adaptive significance of modern reproductive behaviour remains difficult to evaluate, but may be best understood in response to rising investment costs of rearing socially and economically competitive offspring.
The Pepper Mannose-Binding Lectin Gene CaMBL1 Is Required to Regulate Cell Death and Defense Responses to Microbial Pathogens
Authors: Hwang In Sun , Hwang Byung Kook
Published: January 2011

Plant mannose-binding lectins (MBLs) are crucial for plant defense signaling during pathogen attack by recognizing specific carbohydrates on pathogen surfaces. In this study, we isolated and functionally characterized a novel pepper (Capsicum annuum) MBL gene, CaMBL1, from pepper leaves infected with Xanthomonas campestris pv vesicatoria (Xcv). The CaMBL1 gene contains a predicted Galanthus nivalis agglutinin-related lectin domain responsible for the recognition of high-mannose N-glycans but lacks a middle S-locus glycoprotein domain and a carboxyl-terminal PAN-Apple domain. The CaMBL1 protein exhibits binding specificity for mannose and is mainly localized to the plasma membrane. Immunoblotting using a CaMBL1-specific antibody revealed that CaMBL1 is strongly expressed and accumulates in pepper leaves during avirulent Xcv infection. The transient expression of CaMBL1 induces the accumulation of salicylic acid (SA), the activation of defense-related genes, and the cell death phenotype in pepper. The G. nivalis agglutinin-related lectin domain of CaMBL1 is responsible for cell death induction. CaMBL1-silenced pepper plants are more susceptible to virulent or avirulent Xcv infection compared with unsilenced control plants, a phenotype that is accompanied by lowered reactive oxygen species accumulation, reduced expression of downstream SA target genes, and a concomitant decrease in SA accumulation. In contrast, CaMBL1 overexpression in Arabidopsis (Arabidopsis thaliana) confers enhanced resistance to Pseudomonas syringae pv tomato and Alternaria brassicicola infection. Together, these data suggest that CaMBL1 plays a key role in the regulation of plant cell death and defense responses through the induction of downstream defense-related genes and SA accumulation after the recognition of microbial pathogens.
${\rm MgB}_{2}/{\rm MgO/MgB}_{2}$

 Josephson Junctions for High-Speed Circuits
Authors: Chen Ke , Zhuang C. G. , Li Qi , Weng X. , Redwing J. M. , Zhu Y. , Voyles P. M. , Xi X. X.
Published: January 2011

MgB2/MgO/MgB2sandwich-type Josephson junctions have been fabricated using MgB2films grown by hybrid physical-chemical vapor deposition (HPCVD). The MgO barrier and the insulating layer between wiring layers were made by RF magnetron sputtering. The junctions exhibit non-vanishingJcup to 40 K, theTcof MgB2. MgB2wiring is achieved without significantly changing the junction properties. The fabrication and properties of the junctions are described in detail. TheI-Vcurves of the junctions are hysteretic at temperatures below 25 K and are RSJ-like above 25 K. Multiple Andreev reflection was observed, manifested by subgap peaks in the dI/dV-Vcurves and in good agreement with the theory. TheJcspread (1σ) of 10 junctions on one chip is better than 10%, which is likely due to the defects inside the MgO barrier as identified by transmission electron microscopy. Superconducting circuits made of these junctions may be expected to work at frequencies up to 1 THz or at temperatures over 20 K.
Allometric growth and reproductive biology traits of pikeperch Sander lucioperca at the southern edge of its range
Authors: M'Hetli M. , Ben Khemis I. , Hamza N. , Turki B. , Turki O.
Published: January 2011

This study describes some biological traits (allometric relationship, reproductive biology and condition factor) of pikeperch Sander lucioperca at the southern edge of its range. Data were compiled from field studies between January 1997 and January 2009 in three Tunisian reservoirs. Overall, 1497 fish were caught, from which 1308 specimens were sampled and dissected. Sexually undetermined, male and female fish from the different sites exhibited similar allometric growth, expressed through the equation MT = 5 × 10−6LT3·06, where MT is the total mass and LT is the total length. The exponent value is slightly but significantly greater than 3, indicating positive allometric growth. Sex ratio (males:females) was 47:53 but remained balanced only up to 55 cm LT and changed with increasing size towards female dominance. Spawning occurred in March and early April according to the changes in female size‐adjusted gonad mass or corresponding gonado‐somatic index (IG) values. Thermal conditions seemed favourable in February, but March corresponded to the period of equal day and night lengths and the switch towards longer days in terms of photoperiod. Changes in both size‐adjusted MT or Fulton's condition factor and size‐adjusted liver mass or hepato‐somatic index (IH) were clearly associated with reproduction. Reserves were consumed during spring in association with spawning efforts. Nevertheless, the delay before the reconstitution of reserves seemed relatively long (from early spring to late summer) although both thermal and trophic conditions could be considered favourable for active feeding of the fish.
Regulators of G‐protein signalling inFusarium verticillioidesmediate differential host–pathogen responses on nonviable versus viable maize kernels
Authors: MUKHERJEE MALA , KIM JUNG‐EUN , PARK YONG‐SOON , KOLOMIETS MICHAEL V. , SHIM WON‐BO
Published: January 2011

GBB1, a heterotrimeric G‐protein β‐subunit gene, was shown to be a key regulator of fumonisin B1(FB1) biosynthesis in the maize pathogenFusarium verticillioides. In this study, we performed functional analyses of genes that encode putative RGS (regulators of G‐protein signalling) proteins and PhLPs (phosducin‐like proteins) inF. verticillioides. These proteins are known to regulate heterotrimeric G‐protein activity by altering the intrinsic guanosine triphosphatase (GTPase) activity, which, in turn, influences the signalling mechanisms that control fungal growth, virulence and secondary metabolism. Our aim was to isolate and characterize gene(s) that are under the transcriptional control ofGBB1, and to test the hypothesis that these genes are directly associated with FB1regulation and fungal development inF. verticillioideson maize kernels. We first identified eight genes (two PhLPs and six RGSs) in theF. verticillioidesgenome, and a subsequent transcriptional expression study revealed that three RGS genes were up‐regulated in thegbb1deletion (Δgbb1) mutant and one RGS gene was up‐regulated in the wild‐type. To characterize their function, we generated knockout mutants using a homologous recombination strategy. When grown on autoclaved nonviable kernels, two mutants (ΔflbA2 and ΔrgsB) produced significantly higher levels of FB1compared with the wild‐type progenitor, suggesting that the two mutated genes are negative regulators of FB1biosynthesis. ΔflbA2 also showed a severe curly conidia germination pattern, which was contradictory to that observed in the Δgbb1 strain. Strikingly, when these mutants were grown on live maize kernels, we observed contrasting FB1and conidiation phenotypes in fungal mutants, which strongly suggests that these G‐protein regulators have an impact on howF. verticillioidesresponds to host/environmental factors. Our data also provide evidence that fungal G‐protein signalling is important for modulating the ethylene biosynthetic pathway in maize kernels.
Hospitalisation of and mortality from bleeding peptic ulcer in Sweden: a nationwide time‐trend analysis
Authors: Åhsberg K. , Ye W. , Lu Y. , Zheng Z. , Staël von Holstein C.
Published: January 2011

Aliment Pharmacol Ther 2011; 33: 578–584

Background  Time‐trend analyses of incidence and mortality in bleeding peptic ulcer show divergent results.

Aim  To conduct a detailed national analysis of hospitalisation of and mortality from bleeding peptic ulcer in Sweden.

Method  Data from all hospitalisations at departments with primary responsibility for patients with bleeding ulcer in Sweden, with main diagnosis or co‐diagnosis of bleeding ulcer from 1987 to 2005 were retrieved from the Hospital Discharge Register. A validation study was performed due to an uncertainty in diagnostic setting after the introduction of ICD‐10 in 1997. Annual hospitalisation rates per 100 000 inhabitants in relation to gender, age and ulcer location were calculated as well as age‐standardised 30‐day mortality rates.

Results  Hospitalisations for bleeding ulcer decreased from 63.9 to 35.3 per 100 000 inhabitants per year during the study period. The decrease was greater among men (men: from 80.4 to 40.9; women: from 47.7 to 29.7) and in younger age groups. Bleeding gastric ulcer decreased in both genders, and bleeding duodenal ulcer decreased most among men, but was stable in a subgroup of elderly women. Median age increased from 70 to 76 years. Standardised 30‐day mortality increased from 5.3% to 6.2%. The increased mortality was found in those aged more than 65 years and with duodenal ulcer disease, whereas mortality remained unchanged in those with bleeding gastric ulcer.

Conclusion  Hospitalisation rates for bleeding peptic ulcer have markedly decreased in Sweden in all age groups. The 30‐day mortality is low compared with other nationwide studies in the western world, but has increased among patients with duodenal ulcer disease.
Native herbivores and plant facilitation mediate the performance and distribution of an invasive exotic grass
Authors: Cushman J. Hall , Lortie Christopher J. , Christian Caroline E.
Published: January 2011

1. Exotic plant species have become increasingly prominent features of ecological landscapes throughout the world, and their interactions with native and exotic taxa in these novel environments may play critical roles in mediating the dynamics of such invasions.

2. Here, we summarize results from comparative and experimental studies that explore the effects of two factors – herbivory and facilitation – on the performance and distribution of an invasive South African grass,Ehrharta calycina, in a coastal foredune system in northern California, USA.

3. Using a 2‐year exclosure experiment, we show that a native herbivore, black‐tailed jackrabbits (Lepus californicus), significantly reduced the height, shoot production, fecundity and above‐ground biomass of this exotic grass.

4. Data from two comparative studies and a neighbour‐removal experiment revealed thatEhrhartafrequently escaped herbivores by associating with three neighbouring plant species – an exotic perennial grass,Ammophila arenaria, an exotic perennial succulent,Carpobrotus edulis, and a native perennial shrub,Baccharis pilularis.Ehrhartagrowing in association with neighbours was taller, had fewer grazed shoots, produced greater numbers of spikelets and had greater above‐ground biomass than unassociated individuals. Furthermore, removing neighbours generally eliminated these benefits in 7 months, although effects differed among neighbour species.

5. An additional neighbour‐removal experiment conducted in the absence of jackrabbits indicated that neighbour removals did not have significant impacts onEhrhartaheight, shoot production, spikelet production or above‐ground dry biomass. These results suggest that the primary means by whichEhrhartabenefits from neighbouring plants is protection from herbivores – either because they are less apparent to herbivores or less accessible – and thatEhrhartalikely incurred minimal costs from associating with neighbours.

6. Ehrhartawas more frequently associated with neighbours than expected due to chance, and less frequently found in open dune habitat. These results are consistent with the hypothesis that the effects of herbivory and facilitation have been sufficiently strong to shape the local distribution of this invader in the landscape.

7. Synthesis. Our research has demonstrated that herbivory and facilitation have jointly influenced the dynamics of a biological invasion, and highlights the importance of evaluating the effects of multiple interactions on invasions in a single system.
Abrupt ombrotrophication of a boreal aapa mire triggered by hydrological disturbance in the catchment
Authors: Tahvanainen Teemu
Published: January 2011

1. Hydrological changes due to drainage and climate warming can have great impact on the ecosystem balance of boreal mires. The possibility of ombrotrophication, i.e. the development from fen to bog, in response to altered hydrology has not been previously tested. Here, recent changes in vegetation and surface peat are studied in an aapa mire, a typical boreal mire system dominated by fen vegetation. Drainage in the catchment from 1968 onwards led to the change from richly minerogenous to ombrogenous hydrology, thus providing a long‐term ombrotrophication experiment.

2. A sequence of aerial photographs (1941, 1953, 1965, 1974, 1984, 1995, 2005) revealed a dramatic shift from fen vegetation to the nearly complete dominance of peat mosses (Sphagnum) within two decades after the catchment disturbance.

3. A distinct change from Carex peat to Sphagnum peat at the average depth of 23.3 cm (SE 0.8 cm) was found in 18 peat cores. All of the new Sphagnum peat had accumulated within the last four decades. This was verified by the relationship of age and rooting depth of 37 small pines (Pinus sylvestris) and by two pollen density profiles. The ratio Ca/Mg diminished towards the surface of peat profiles indicating change from minerogenous to ombrogenous hydrology. In accordance, extremely low pH (range 3.8–4.2) and conductivity (average 14.5 μs cm−1) were measured in the surface pore water.

4. The average total dry mass of new Sphagnum peat was 7042 g m−2 (SE 442) and the recent apparent rate of carbon accumulation was 100.6 g m−2 year−1 (SE 6.3), as calculated for a 35‐year period and 50% carbon content.

5. Synthesis. Remarkable potential for vegetation change and increase of peat growth is demonstrated in boreal aapa mires. Ombrotrophication can be initiated within a few decades in response to reduced input of minerogenous water. Future changes in the hydrological cycle, as indicated by climate change models, are similar to the impact of catchment disturbance in aapa mires. Diminished total water budgets during the summer cause a decrease of minerogenous input and a draw‐down of water level, both of which may promote the growth of Sphagnum over fen vegetation.
Construct validity of the SF‐12 in three different samples
Authors: Jakobsson Ulf , Westergren Albert , Lindskov Susanne , Hagell Peter
Published: January 2011

Rationale, aims and objectives  Studies have challenged the validity and underlying measurement model of the physical and mental component summary scores of the 36‐item Short‐Form Health Survey in, for example the elderly and people with neurological disorders. However, it is unclear to what extent these observations translate to physical and mental component summary scores derived from the 12‐item short form (SF‐12) of the 36‐item Short‐Form Health Survey. This study evaluated the construct validity of the SF‐12 in elderly people and people with Parkinson's disease (PD) and stroke.

Methods  SF‐12 data from a general elderly (aged 75+) population (n = 4278), people with PD (n = 159) and stroke survivors (n = 89) were analysed regarding data quality, reliability (coefficient alpha) and internal construct validity. The latter was assessed through item‐total correlations, exploratory and confirmatory factor analyses.

Results  Completeness of data was high (93–98.8%) and reliability was acceptable (0.78–0.85). Item‐total correlations argued against the suggested items‐to‐summary scores structure in all three samples. Exploratory factor analyses failed to support a two‐dimensional item structure among elderly and stroke survivors, and cross‐loadings of items were seen in all three samples. Confirmatory factor analyses showed lack of fit between empirical data and the proposed items‐to‐summary measures structure in all samples.

Conclusions  These observations challenge the validity and interpretability of SF‐12 scores among the elderly, people with PD and stroke survivors. The standard orthogonally weighted SF‐12 scoring algorithm is cautioned against. Instead, when the assumed two‐dimensional structure is supported in the data, oblique scoring algorithms appear preferable. Failure to consider basic scoring assumptions may yield misleading results.
Effect of visit length and a clinical decision support tool on abdominal aortic aneurysm screening rates in a primary care practice
Authors: Eaton John , Reed Darcy , Angstman Kurt B. , Thomas Kris , North Frederick , Stroebel Robert , Tulledge‐Scheitel Sidna M. , Chaudhry Rajeev
Published: January 2011

Rationale, aims and objectives  In 2005, the US Preventive Services Task Force issued recommendations for one‐time abdominal aortic aneurysm (AAA) screening using abdominal ultrasonography in men aged 65 to 75 years with a history of smoking. However, despite a mortality rate of up to 80% for ruptured AAAs, providers order the screening for a minority of patients. We examined AAA screening rates among providers and investigated the role of visit duration and other factors in whether patients received screening. We also looked for potential interventions to improve compliance.

Methods  We retrospectively reviewed the records of patients who visited our clinic over a 4‐month period and met the US Preventive Services Task Force criteria for AAA screening when our practice had a real‐time decision support tool implemented to identify patients due for the screening. We also surveyed our clinic's providers about their knowledge and attitudes regarding AAA screening.

Results  Despite the use of physician reminders, providers ordered screening for only 12.9% of eligible patients. Screening was more likely to be ordered during longer visits versus shorter ones (24% vs. 6%). When surveyed, most providers (70.6%) indicated that a nurse‐directed ordering system would improve compliance.

Conclusions  This study illustrates that physician reminders alone are not sufficient to improve care and that more time is needed for preventive services. This provides additional support for the use of a multidisciplinary approach to preventive screening, as in a patient‐centred medical home. In a patient‐centred medical home, a care team of physicians, nurses and office staff use technology such as clinical decision support to provide comprehensive, coordinated patient care.
Hepatitis C virus infection during pregnancy and the newborn period – are they opportunities for treatment?
Authors: Arshad M. , El‐Kamary S. S. , Jhaveri R.
Published: January 2011

Summary. The worldwide prevalence of hepatitis C virus (HCV) infection in pregnant women is estimated to be between 1 and 8% and in children between 0.05% and 5%. While parenteral transmission is still common in children living in developing countries, perinatal transmission is now the leading cause of HCV transmission in developed countries. The absence of an HCV vaccine or approved therapy during pregnancy means that prevention of vertical transmission is still not possible. However, a low vertical transmission rate of 3–5%, a high rate of spontaneous clearance (25–50%) and delayed morbidity have resulted in HCV being overlooked in pregnant women and their infants. Yet a study of the natural history in mothers and children demonstrates that the prognosis of HCV can vary greatly and should be taken seriously. Factors known to increase the risk of perinatal transmission include HIV coinfection and higher maternal viral loads, while elective C‐section and withholding breastfeeding have not been demonstrated to reduce vertical transmission. Current guidelines for the diagnosis of persistent perinatal infection require a positive anti‐HCV test in infants born to infected mothers after 12 months or two positive HCV RNA tests at least 6 months apart. Current HCV treatment options using pegylated interferon and ribavirin are both unsuitable for use in pregnancy and infancy. However, new agents currently in preclinical phases of development, along with the recently identified association between single‐nucleotide polymorphisms within the IL28 gene and treatment response, may serve to create a therapeutic window for these patients.
Wild immunology
Authors: PEDERSEN AMY B. , BABAYAN SIMON A.
Published: January 2011

In wild populations, individuals are regularly exposed to a wide range of pathogens. In this context, organisms must elicit and regulate effective immune responses to protect their health while avoiding immunopathology. However, most of our knowledge about the function and dynamics of immune responses comes from laboratory studies performed on inbred mice in highly controlled environments with limited exposure to infection. Natural populations, on the other hand, exhibit wide genetic and environmental diversity. We argue that now is the time for immunology to be taken into the wild. The goal of ‘wild immunology’ is to link immune phenotype with host fitness in natural environments. To achieve this requires relevant measures of immune responsiveness that are both applicable to the host–parasite interaction under study and robustly associated with measures of host and parasite fitness. Bringing immunology to nonmodel organisms and linking that knowledge host fitness, and ultimately population dynamics, will face difficult challenges, both technical (lack of reagents and annotated genomes) and statistical (variation among individuals and populations). However, the affordability of new genomic technologies will help immunologists, ecologists and evolutionary biologists work together to translate and test our current knowledge of immune mechanisms in natural systems. From this approach, ecologists will gain new insight into mechanisms relevant to host health and fitness, while immunologists will be given a measure of the real‐world health impacts of the immune factors they study. Thus, wild immunology can be the missing link between laboratory‐based immunology and human, wildlife and domesticated animal health.
The Relationship Between Interferon‐γ Gene Polymorphism and Acute Kidney Allograft Rejection
Authors: Zibar L. , Wagner J. , Pavlinić D. , Galić J. , Pasini J. , Juras K. , Barbić J.
Published: January 2011

Cytokine gene polymorphisms have been associated with modified gene expression and cytokine production. Gamma interferon (IFN‐γ) plays an important role in the pathogenesis of kidney transplant rejection. This study evaluated the association between IFN‐γ gene polymorphisms and the history of acute allograft rejection in 53 adult first‐transplant recipients receiving cadaveric kidney grafts. They were followed up in a single centre until 2006, for a median time of 4 years after transplantation (1–22 years). IFN‐γ gene polymorphisms +874 T/A (rs2430561) were determined by polymerase chain reaction (PCR). T/T high IFN‐γ genotype was found in 12, intermediate T/A in 29 and low A/A in 12 patients. Twenty‐six acute kidney rejection episodes were evidenced in 20 patients, of which none occurred in the 12 patients with low IFN‐γ genotype A/A. Age, gender, number of HLA (human leukocyte antigen) mismatches, ABO blood groups, HLA, time after transplantation, creatinine clearance and immunosuppressive regimens were excluded as confounding factors associated with IFN‐γ genotype distribution between rejectors and non‐rejectors. IFN‐γ gene polymorphisms could be an important risk factor for acute kidney transplant rejection, whereas the low A/A IFN‐γ genotype could be protective against rejection.
Functional implication of the MYB transcription factor RVE8/LCL5 in the circadian control of histone acetylation
Authors: Farinas Benoit , Mas Paloma
Published: January 2011

Despite our increasing understanding of the molecular determinants essential for circadian clock function, we still lack a complete picture of the mechanisms contributing to clock progression in plants. Here, we explore the role of REVEILLE8/LHY‐CCA1‐LIKE5 (RVE8/LCL5) within the Arabidopsis circadian system. RVE8/LCL5 encodes a MYB‐like transcription factor similar to CIRCADIAN CLOCK‐ASSOCIATED1 (CCA1) and ELONGATED HYPOCOTYL (LHY), which are essential regulators of the Arabidopsis circadian clock. Consistent with the sequence similarity, the rhythmic expression of RVE8/LCL5 shows a morning acrophase comparable to that of CCA1 and LHY. Plants mis‐expressing RVE8/LCL5 display a variety of circadian phenotypes, including altered circadian gene expression and photoperiodic flowering time. Similar to CCA1, RVE8/LCL5 regulates the expression of the oscillator gene TOC1 (TIMING OF CAB EXPRESSION1) by associating with the TOC1 promoter and by modulating the pattern of histone 3 (H3) acetylation. However, the mechanisms of RVE8/LCL5 and CCA1 activity in this regulation differ markedly. Indeed, the use of chromatin immunoprecipitation and pharmacological inhibition assays reveals that RVE8/LCL5 favours a hyper‐acetylated state of H3 at the TOC1 promoter, which may facilitate the rising phase of TOC1. In contrast, CCA1 represses TOC1 expression by promoting histone deacetylation. Thus, despite the sequence homology and the similar morning phase of expression, RVE8/LCL5 and CCA1 have opposing regulatory functions within the Arabidopsis circadian clock, although CCA1 has a more predominant role. We propose that contrasting chromatin compaction and transcriptional modulation through the opposing activities of RVE8/LCL5 and CCA1 might provide a fine‐tuning mechanism for precisely shaping the TOC1 circadian waveform in Arabidopsis.
Methanol is an endogenous elicitor molecule for the synthesis of tryptophan and tryptophan‐derived secondary metabolites upon senescence of detached rice leaves
Authors: Kang Kiyoon , Park Sangkyu , Natsagdorj Uyanga , Kim Young Soon , Back Kyoungwhan
Published: January 2011

During senescence of detached rice leaves, tryptophan (Trp) and Trp‐derived secondary metabolites such as serotonin and 4‐coumaroylserotonin accumulated in concert with methanol (MeOH) production. This senescence‐induced MeOH induction was closely associated with levels of pectin methylesterase (PME)1 mRNA and PME enzyme activity. Exogenous challenge of detached rice leaves with 1% MeOH accelerated Trp and serotonin biosynthesis with induction of the corresponding genes. No other solvents, including ethanol, resulted in a Trp‐inducing effect. This MeOH‐induced Trp synthesis was positively regulated by abscisic acid but negatively regulated by cytokinin, suggesting hormonal involvement in the action of MeOH. Endogenous overproduction or suppression of MeOH either by PME1 overexpression or RNA interference (RNAi) gene silencing revealed that PME1 overexpressing lines produced twofold higher Trp levels with elevated Trp biosynthetic gene expression, whereas RNAi lines showed twofold reduction in Trp level in healthy control rice leaves, suggesting that MeOH acts as an endogenous elicitor to enhance Trp biosynthesis. Among many transcription factors induced following MeOH treatment, the WRKY family showed significant induction patterns, of which WRKY14 appeared to play a key regulatory role in MeOH‐induced Trp and Trp‐derived secondary metabolite biosynthesis.