bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of hemiparasitic plant removal on community structure and seedling establishment in semi‐natural grasslands
Authors: Demey Andreas , De Frenne Pieter , Baeten Lander , Verstraeten Gorik , Hermy Martin , Boeckx Pascal , Verheyen Kris
Published: December 2014

Question

Hemiparasitic plants can profoundly affect the structure of the community in which they occur, mainly due to parasitic suppression of hosts. As a consequence, non‐host species have the opportunity to colonize resulting gaps. In contrast to most grassland species, hemiparasites are generally short‐lived and can reach high densities; as a consequence, vegetation gaps are left after their death. These gaps form microsites more suitable for seed germination and therefore might increase recruitment of other species. Which species suffer or profit from parasitism and is there a positive effect on seedling establishment?

Location

Semi‐natural grasslands in northern Belgium.

Methods

We selected two hemiparasitic plant species from contrasting vegetation types: Rhinanthus angustifolius growing in mesotrophic grassland and Pedicularis sylvatica growing in oligotrophic heath‐grassland. A weeding experiment was set up at six sites in which the hemiparasite was repeatedly removed in half of the plots during three growing seasons. The abundance change of individual species was compared between weeded and control plots. After the second growing season, seeds of up to ten species were added. The number of seedlings in the third year was then compared between weeded and control plots.

Results

Rhinanthus removal significantly affected the abundance of species relative to control plots, both positively and negatively, and decreased the species evenness. Pedicularis removal only increased the abundance of some species. Only Juncaceae (but no other graminoid families) increased after Rhinanthus and Pedicularis weeding, and there was considerable variation within functional groups. Moreover, based on our observations, we propose as a new hypothesis that species with persistent clonal spread are more vulnerable to parasitism. Once attached, resources are potentially drawn from a whole network of interconnected ramets. Finally, only half of the sown species successfully established seedlings; hemiparasite removal had a significantly negative effect on seedling number for two of these species.

Conclusions

Effects of hemiparasites on species differ considerably, also within functional groups. Persistent clonal spread emerges as an important plant trait determining vulnerability to hemiparasites. Finally, our results suggest that hemiparasitic plants might have a limited positive effect on seedling establishment in these semi‐natural grasslands where chances for successful establishment were shown to be low.
Blue whale population structure along the eastern South Pacific Ocean: evidence of more than one population
Authors: Torres‐Florez J. P. , Hucke‐Gaete R. , LeDuc R. , Lang A. , Taylor B. , Pimper L. E. , Bedriñana‐Romano L. , Rosenbaum H. C. , Figueroa C. C.
Published: December 2014

Blue whales (Balaenoptera musculus) were among the most intensively exploited species of whales in the world. As a consequence of this intense exploitation, blue whale sightings off the coast of Chile were uncommon by the end of the 20th century. In 2004, a feeding and nursing ground was reported in southern Chile (SCh). With the aim to investigate the genetic identity and relationship of these Chilean blue whales to those in other Southern Hemisphere areas, 60 biopsy samples were collected from blue whales in SCh between 2003 and 2009. These samples were genotyped at seven microsatellite loci and the mitochondrial control region was sequenced, allowing us to identify 52 individuals. To investigate the genetic identity of this suspected remnant population, we compared these 52 individuals to blue whales from Antarctica (ANT, n = 96), Northern Chile (NCh, n = 19) and the eastern tropical Pacific (ETP, n = 31). No significant differentiation in haplotype frequencies (mtDNA) or among genotypes (nDNA) was found between SCh, NCh and ETP, while significant differences were found between those three areas and Antarctica for both the mitochondrial and microsatellite analyses. Our results suggest at least two breeding population units or subspecies exist, which is also supported by other lines of evidence such as morphometrics and acoustics. The lack of differences detected between SCh/NCh/ETP areas supports the hypothesis that eastern South Pacific blue whales are using the ETP area as a possible breeding area. Considering the small population sizes previously reported for the SCh area, additional conservation measures and monitoring of this population should be developed and prioritized.
Demographic inferences using short‐read genomic data in an approximate Bayesian computation framework: in silico evaluation of power, biases and proof of concept in Atlantic walrus
Authors: Shafer Aaron B. A. , Gattepaille Lucie M. , Stewart Robert E. A. , Wolf Jochen B. W.
Published: December 2014

Approximate Bayesian computation (ABC) is a powerful tool for model‐based inference of demographic histories from large genetic data sets. For most organisms, its implementation has been hampered by the lack of sufficient genetic data. Genotyping‐by‐sequencing (GBS) provides cheap genome‐scale data to fill this gap, but its potential has not fully been exploited. Here, we explored power, precision and biases of a coalescent‐based ABC approach where GBS data were modelled with either a population mutation parameter (θ) or a fixed site (FS) approach, allowing single or several segregating sites per locus. With simulated data ranging from 500 to 50 000 loci, a variety of demographic models could be reliably inferred across a range of timescales and migration scenarios. Posterior estimates were informative with 1000 loci for migration and split time in simple population divergence models. In more complex models, posterior distributions were wide and almost reverted to the uninformative prior even with 50 000 loci. ABC parameter estimates, however, were generally more accurate than an alternative composite‐likelihood method. Bottleneck scenarios proved particularly difficult, and only recent bottlenecks without recovery could be reliably detected and dated. Notably, minor‐allele‐frequency filters – usual practice for GBS data – negatively affected nearly all estimates. With this in mind, we used a combination of FS and θ approaches on empirical GBS data generated from the Atlantic walrus (Odobenus rosmarus rosmarus), collectively providing support for a population split before the last glacial maximum followed by asymmetrical migration and a high Arctic bottleneck. Overall, this study evaluates the potential and limitations of GBS data in an ABC‐coalescence framework and proposes a best‐practice approach.
MHC variation reflects the bottleneck histories of New Zealand passerines
Authors: Sutton Jolene T. , Robertson Bruce C. , Jamieson Ian G.
Published: December 2014

Most empirical evidence suggests that balancing selection does not counter the effects of genetic drift in shaping postbottleneck major histocompatibility complex (MHC) genetic diversity when population declines are severe or prolonged. However, few studies have been able to include data from historical specimens, or to compare populations/species with different bottleneck histories. In this study, we examined MHC class II B and microsatellite diversity in four New Zealand passerine (songbird) species that experienced moderate to very severe declines. We compared diversity from historical samples (collected c. 1884–1938) to present‐day populations. Using a Bayesian framework, we found that the change in genetic diversity from historical to contemporary samples was affected by three main factors: (i) whether the data were based on MHC or microsatellite markers, (ii) species (as a surrogate for bottleneck severity) and (iii) whether the comparison between historical and contemporary samples was made using historical samples originating from the mainland, or using historical samples originating from islands. The greatest losses in genetic diversity occurred for the most severely bottlenecked species, particularly between historical mainland and contemporary samples. Additionally, where loss of diversity occurred, the change was greater for MHC genes compared to microsatellite loci.
Role of Dickeya dadantii 3937 chemoreceptors in the entry to Arabidopsis leaves through wounds
Authors: Río‐Álvarez Isabel , Muñoz‐Gómez Cristina , Navas‐Vásquez Mariela , Martínez‐García Pedro M. , Antúnez‐Lamas María , Rodríguez‐Palenzuela Pablo , López‐Solanilla Emilia
Published: December 2014

Chemotaxis enables bacteria to move towards an optimal environment in response to chemical signals. In the case of plant‐pathogenic bacteria, chemotaxis allows pathogens to explore the plant surface for potential entry sites with the ultimate aim to prosper inside plant tissues and to cause disease. Chemoreceptors, which constitute the sensory core of the chemotaxis system, are usually transmembrane proteins which change their conformation when sensing chemicals in the periplasm and transduce the signal through a kinase pathway to the flagellar motor. In the particular case of the soft‐rot pathogen Dickeya dadantii 3937, jasmonic acid released in a plant wound has been found to be a strong chemoattractant which drives pathogen entry into the plant apoplast. In order to identify candidate chemoreceptors sensing wound‐derived plant compounds, we carried out a bioinformatics search of candidate chemoreceptors in the genome of Dickeya dadantii 3937. The study of the chemotactic response to several compounds and the analysis of the entry process to Arabidopsis leaves of 10 selected mutants in chemoreceptors allowed us to determine the implications of at least two of them (ABF‐0020167 and ABF‐0046680) in the chemotaxis‐driven entry process through plant wounds. Our data suggest that ABF‐0020167 and ABF‐0046680 may be candidate receptors of jasmonic acid and xylose, respectively.
Fusarium brain abscess: case report and literature review
Authors: Garcia Raquel Ramos , Min Zaw , Narasimhan Supriya , Bhanot Nitin
Published: December 2014

Severely immunocompromised patients such as those with haematological malignancies and haematopoietic stem cell transplant recipients are at an increased risk of acquiring invasive mould infections. Fusarium, a ubiquitous fungus, can cause potentially fatal infections in such hosts. It usually manifests as skin lesions, fevers and sino‐pulmonary infections. Brain abscesses have been reported, but are relatively uncommon. We report a case of a 50‐year‐old patient with acute lymphocytic leukaemia and failed autologous peripheral stem cell transplant that presented with new onset seizures and was found to have Fusarium solani brain abscess. Nasal route was the presumed mode of entry of the fungus into the cerebrum. Treatment comprised surgical excision of the lesion, and antimycotic therapy with liposomal amphotericin B and voriconazole. Despite aggressive therapy, patient succumbed to the disease. We have provided an overview of infections secondary to Fusarium, along with a review of the central nervous system involvement by this pathogenic mould.
Arctic fungal communities associated with roots of Bistorta vivipara do not respond to the same fine‐scale edaphic gradients as the aboveground vegetation
Authors: Mundra Sunil , Halvorsen Rune , Kauserud Håvard , Müller Eike , Vik Unni , Eidesen Pernille B.
Published: December 2014

Soil conditions and microclimate are important determinants of the fine‐scale distribution of plant species in the Arctic, creating locally heterogeneous vegetation. We hypothesize that root‐associated fungal (RAF) communities respond to the same fine‐scale environmental gradients as the aboveground vegetation, creating a coherent pattern between aboveground vegetation and RAF.

We explored how RAF communities of the ectomycorrhizal (ECM) plant Bistorta vivipara and aboveground vegetation structure of arctic plants were affected by biotic and abiotic variables at 0.3–3.0‐m scales. RAF communities were determined using pyrosequencing. Composition and spatial structure of RAF and aboveground vegetation in relation to collected biotic and abiotic variables were analysed by ordination and semi‐variance analyses.

The vegetation was spatially structured along soil C and N gradients, whereas RAF lacked significant spatial structure. A weak relationship between RAF community composition and the cover of two ECM plants, B. vivipara and S. polaris, was found, and RAF richness increased with host root length and root weight.

Results suggest that the fine‐scale spatial structure of RAF communities of B. vivipara and the aboveground vegetation are driven by different factors. At fine spatial scales, neighbouring ECM plants may affect RAF community composition, whereas soil nutrients gradients structure the vegetation.
Understanding Price Stickiness: Firm‐level Evidence on Price Adjustment Lags and Their Asymmetries
Authors: Dias Daniel A. , Marques Carlos Robalo , Martins Fernando , Santos Silva J. M. C.
Published: December 2014

We study the speed of price reactions to positive and negative demand and cost shocks. Our findings suggest that price adjustment lags vary in line with the predictions of optimal price setting models. Moreover, we find that the firms' reactions are asymmetric, and that these asymmetries cannot be fully explained by any single theoretical model of asymmetric price adjustment. Overall, these results suggest that the reaction to monetary policy shocks may depend on which firms or sectors are particularly affected by them and, therefore, that richer models are needed to fully understand the effects of monetary policy.
A positive association between ants and spiders and potential mechanisms driving the pattern
Authors: Marín Linda , Jackson Doug , Perfecto Ivette
Published: December 2014

Biotic interactions play a central role in determining species distribution and abundance. Some ants act as keystone species affecting the distribution and abundance of other species, including spiders. In coffee plantationsPocobletussp. spiders are significantly more abundant in coffee plants patrolled by the aggressive arboreal antsAzteca sericeasur. However, it is unknown if other ant species influence this ant–spider association, how these associates are spatially distributed, and which are the potential drivers of this association. Here we examine the influence of ants,Azteca sericeasurandPheidole synanthropica, and coffee branch density onPocobletusabundance in a coffee farm in southern Mexico. We also analyze the spatial distribution and abundance ofPocobletussp., in relation to the spatial distribution ofA. sericeasurandP. synanthropica. Finally, we examine prey availability and enemy‐free space as potential mechanisms underlying this ant–spider association. Results show thatPocobletusabundance is positively correlated with coffee branch density andA. sericeasurandP. synanthropicapresence. Furthermore, the spatial distribution analysis shows that in 20 × 20 m plotsPocobletusis strongly associated toA. sericeasur,but not toP. synanthropica. Results show that insect abundance in bothPocobletus's webs and sticky traps was significantly higher in the presence ofA. sericeasurwhereas the abundance of the predators ofPocobletusdecreased inA. sericeasur'spresence; suggesting positive direct and indirect effects ofA. sericeasuronPocobletus. Overall, this study highlights the strong influence of ants and plant characteristics on the abundance and spatial distribution of spiders as well their indirect effects on other taxa.
The Shadows of Normative Power in Asia: Framing the International Agency of China, India, and Japan
Authors: Kavalski Emilian
Published: December 2014

While the analysis of normative power has dominated the debates in European international relations studies for the past 20 years, this topic has hardly been broached in the analysis of Asian international affairs. This investigation aims to redress this trend by taking stock of the current state of the art. This exploration therefore contends that normative powers are those actors that are recognized as such by others. This qualifies Ian Manners' oft‐quoted proposition that normative powers are only those actors that have the ability to “shape what can be ‘normal’ in international life.” The proposition is that the definitions of the “normal” are not merely undertaken by normative power, but that they emerge in the context of its interaction with others. Recognition, in this setting, is indicated by the specific reactions of target states. In this respect, the issue is not merely about being and becoming a normative power, but also about being recognized as one by others. The study will detail this proposition by undertaking an analytical parallel assessment of normative power Europe, normative power China, normative power India, and normative power Japan.
Mongolia's Political Change and Human Rights in Five‐Phase Spiral Model: Implications for North Korea
Authors: Heo Man‐ho
Published: December 2014

This study examines the changes in Mongolia's human rights policy in relation to its political change, using the “five‐phase spiral model” proposed by Thomas Risse and colleagues, which offers a framework to explain the process whereby repressive governments adopt human rights. As a result, my findings clarify the theoretical relevance and deviance of the model in the case of Mongolia, while identifying possible implications for the case of North Korea. According to the model, the process whereby international human rights norms are internalized and affect domestic institutional change requires sustained pressure from bilateral and multilateral networks on the repressive government in the first and second phases to induce policy changes in the third phase, “tactical concessions.” I examine the extent to which Mongolia followed such a process, along with the role of its regime change as a requisite for its successive move from the third to the fourth phase, “prescriptive status.” When Mongolian human rights policy moved from the second phase, “denial,” to the third phase, transnational human rights networks were not dominant actors. Yet, clear changes in human rights occurred in the aftermath of the regime change, suggesting that this transition was, indeed, a prerequisite. As to whether the change in the Mongolian government's human rights policy was also a result of “boomerang effects” brought about by a developed civil society and transnational networks, the effects were found to be reserved under the socialist regime, yet positive after democratization. Therefore, the Mongolian experience suggests the need for an engagement policy with North Korea, based on its significantly extended “second social sphere,” in order to facilitate a civil society and social networks, democratization of the governing party, and the emergence of a moderate government in North Korea with a self‐sacrificing supreme leader like Jambyn Batmonkh.
Simulated fluid resuscitation for toddlers and young children: effect of syringe size and hand fatigue
Authors: Toshniwal Gokul , Ahmed Zulfiqar , Sengstock David
Published: December 2014

Background

In small children, fluid resuscitation requires rapid administration of a relatively large fluid volume. This is often achieved manually. The optimal syringe size is unknown.

Objectives

The purpose of this study was to determine which syringe delivers fluid in the shortest time. The secondary outcome was to determine which syringe was associated with hand fatigue.

Methods

Participants (n = 20) performed a simulated fluid resuscitation using four syringe sizes: 5 ml, 10 ml, 20 ml, and 60 ml. The ‘pull and push’ method was used to transfer 250 ml of lactated Ringer's solution from a bag, through IV tubing, into a container. Fluid transfer time (seconds) and hand fatigue were measured.

Results

A ‘U’‐shaped curve was identified between syringe size and transfer time (P < 0.0001). The 10‐ml and 20‐ml syringes did not differ significantly (231 ± 43 vs 228 ± 45 s, P > 0.2, respectively). The 5‐ml and 60‐ml syringes did not differ significantly (273 ± 69 s vs 295 ± 64, P = 0.2, respectively). However, the 5‐ml syringe required significantly more time than the 10‐ml (by 42 s, P = 0.002) or the 20‐ml (by 45 s, P = 0.001) syringes. The 60‐ml syringe also required significantly more time than the 10‐ml (by 64 s, P < 0.0001) or 20‐ml (by 67 s, P = 0.0001) syringe. Although all participants transferred the 250 ml, hand fatigue increased as syringe size increased: 5 ml (n = 3), 10 ml (n = 4), 20 ml (n = 7), and 60 ml (n = 15). Most participants preferred using the 10‐ml syringe (n = 11/20), followed by 20‐ml (n = 6/20), 5‐ml (n = 3/20), and 60‐ml (n = 0/20) syringes.

Conclusion

Manual fluid resuscitation using the ‘pull and push’ method is most rapidly accomplished with the 10‐ml or 20‐ml syringes. The 60‐ml syringe is associated with the most hand fatigue. Participants most preferred the 10‐ml or 20‐ml syringes.
The Portuguese version of the Outcome Questionnaire (OQ‐45): Normative data, reliability, and clinical significance cut‐offs scores
Authors: Machado Paulo P. P. , Fassnacht Daniel B.
Published: December 2014

Objectives

The Outcome Questionnaire (OQ‐45) is one of the most extensively used standardized self‐report instruments to monitor psychotherapy outcomes. The questionnaire is designed specifically for the assessment of change during psychotherapy treatments. Therefore, it is crucial to provide norms and clinical cut‐off values for clinicians and researchers. The current study aims at providing study provides norms, reliability indices, and clinical cut‐off values for the Portuguese version of the scale.

Method

Data from two large non‐clinical samples (high school/university, N = 1,669; community, N = 879) and one clinical sample (n = 201) were used to investigate psychometric properties and derive normative data for all OQ‐45 subscales and the total score.

Results

Significant and substantial differences were found for all subscales between the clinical and non‐clinical sample. The Portuguese version also showed adequate reliabilities (internal consistency, test–retest), which were comparable to the original version. To assess individual clinical change, clinical cut‐off values and reliable change indices were calculated allowing clinicians and researchers to monitor and evaluate clients' individual change.

Conclusion

The Portuguese version of the OQ‐45 is a reliable instrument with comparable Portuguese norms and cut‐off scores to those from the original version. This allows clinicians and researchers to use this instrument for evaluating change and outcome in psychotherapy.

Practitioner points

This study provides norms for non‐clinical and clinical Portuguese samples and investigates the reliability (internal consistency and test–retest) of the OQ‐45.

Cut‐off values and reliable change index are provided allowing clinicians to evaluate clinical change and clients' response to treatment, monitoring the quality of mental health care services.

These can be used, in routine clinical practice, as benchmarks for treatment progress and to empirically base clinical decisions such as continuation of treatment or considering termination.
Overexpression of ubiquitin‐like LpHUB1 gene confers drought tolerance in perennial ryegrass
Authors: Patel Minesh , Milla‐Lewis Susana , Zhang Wanjun , Templeton Kerry , Reynolds William C. , Richardson Kim , Biswas Margaret , Zuleta Maria C. , Dewey Ralph E. , Qu Rongda , Sathish Puthigae
Published: December 2014

HUB1, also known as Ubl5, is a member of the subfamily of ubiquitin‐like post‐translational modifiers. HUB1 exerts its role by conjugating with protein targets. The function of this protein has not been studied in plants. A HUB1 gene, LpHUB1, was identified from serial analysis of gene expression data and cloned from perennial ryegrass. The expression of this gene was reported previously to be elevated in pastures during the summer and by drought stress in climate‐controlled growth chambers. Here, pasture‐type and turf‐type transgenic perennial ryegrass plants overexpressing LpHUB1 showed improved drought tolerance, as evidenced by improved turf quality, maintenance of turgor and increased growth. Additional analyses revealed that the transgenic plants generally displayed higher relative water content, leaf water potential, and chlorophyll content and increased photosynthetic rate when subjected to drought stress. These results suggest HUB1 may play an important role in the tolerance of perennial ryegrass to abiotic stresses.
Geach's Three Most Inspiring Errors Concerning Medieval Logic
Authors: Klima Gyula
Published: December 2014

This paper analyses the import of three claims extracted from Geach's works concerning (i) theories of predication and the reference of common terms, (ii) the notions of being or existence, and (iii) the force/content distinction and theories of valid inference, respectively. The paper highlights the theoretical and historical errors involved in these claims as well as their enormous influence and inspiration in the field of the philosophical study of medieval logic and metaphysics.
Evaluation of Nursing Interventions Designed to Impact Knowledge, Behaviors, and Health Outcomes for Rural African‐Americans: An Integrative Review
Authors: Abbott Laurie S.
Published: December 2014

Objective

The purpose of this review is to evaluate published nursing research reports of effective health promotion strategies for preventing cardiovascular disease, cancer and stroke among rural African Americans.

Design and Sample

A review of the nursing literature was conducted to select intervention studies published within the past decade (2004‐2014). An integrative review method was adapted to evaluate, analyze, and synthesize the nursing research articles that met the inclusion criteria.

Results

Data evaluation encompassed displaying the data in a literature matrix for the appraisal of research components employed in the studies. The major intervention strategies reported in the health promotion studies were reduced, displayed in tables, and synthesized. The resultant comparison of the studies can potentially guide nurse researchers in designing health promotion interventions targeting rural African Americans.

Discussion

Public health nurses are uniquely qualified to assist in the national goals of eliminating health disparities for population groups at risk for poor health outcomes by the development and implementation of evidence‐based health promotion interventions. Assisting healthy individuals within community settings reduce risk factors for cardiovascular disease and cancer can potentially decrease mortality rates associated with these diseases and improve health equity for disadvantaged populations.
Effects of Substituents on Synthetic Analogs of Chlorophylls. Part 4: How Formyl Group Location Dictates the Spectral Properties of Chlorophylls b, d and f
Authors: Yuen Jonathan M. , Harris Michelle A. , Liu Mengran , Diers James R. , Kirmaier Christine , Bocian David F. , Lindsey Jonathan S. , Holten Dewey
Published: December 2014

Photosynthetic organisms are adapted to light characteristics in their habitat in part via the spectral characteristics of the associated chlorophyll pigments, which differ in the position of a formyl group around the chlorin macrocycle (chlorophylls b, d, f) or no formyl group (chlorophyll a). To probe the origin of this spectral tuning, the photophysical and electronic structural properties of a new set of synthetic chlorins are reported. The zinc and free base chlorins have a formyl group at either the 2‐ or 3‐position. The four compounds have fluorescence yields in the range 0.19–0.28 and singlet excited‐state lifetimes of ca 4 ns for zinc chelates and ca 8 ns for the free base forms. The photophysical properties of the 2‐ and 3‐formyl zinc chlorins are similar to those observed previously for 13‐formyl or 3,13‐diformyl chlorins, but differ markedly from those for 7‐formyl analogs. Molecular‐orbital characteristics obtained from density functional theory (DFT) calculations were used as input to spectral simulations employing the four‐orbital model. The analysis has uncovered the key changes in electronic structure engendered by the presence/location of a formyl group at various macrocycle positions, which is relevant to understanding the distinct spectral properties of the natural chlorophylls a, b, d and f.
Germination sensitivities to water potential among co‐existing C3 and C4 grasses of cool semi‐arid prairie grasslands
Authors: Mollard F. P. O. , Naeth M. A.
Published: December 2014

An untested theory states that C4 grass seeds could germinate under lower water potentials (Ψ) than C3 grass seeds. We used hydrotime modelling to study seed water relations of C4 and C3 Canadian prairie grasses to address Ψ divergent sensitivities and germination strategies along a risk‐spreading continuum of responses to limited water. C4 grasses were Bouteloua gracilis, Calamovilfa longifolia and Schizachyrium scoparium; C3 grasses were Bromus carinatus, Elymus trachycaulus, Festuca hallii and Koeleria macrantha. Hydrotime parameters were obtained after incubation of non‐dormant seeds under different Ψ PEG 6000 solutions. A t‐test between C3 and C4 grasses did not find statistical differences in population mean base Ψ (Ψb(50)). We found idiosyncratic responses of C4 grasses along the risk‐spreading continuum. B. gracilis showed a risk‐taker strategy of a species able to quickly germinate in a dry soil due to its low Ψb(50) and hydrotime (θH). The high Ψb(50) of S. scoparium indicates it follows the risk‐averse strategy so it can only germinate in wet soils. C. longifolia showed an intermediate strategy: the lowest Ψb(50) yet the highest θH. K. macrantha, a C3 grass which thrives in dry habitats, had the highest Ψb(50), suggesting a risk‐averse strategy for a C3 species. Other C3 species showed intermediate germination patterns in response to Ψ relative to C4 species. Our results indicate that grasses display germination sensitivities to Ψ across the risk‐spreading continuum of responses. Thus seed water relations may be poor predictors to explain differential recruitment and distribution of C3 and C4 grasses in the Canadian prairies.
Alternative Politics and Attitudes toward the Welfare State: Theory and Empirical Findings from Israel
Authors: Mizrahi Shlomo , Yuval Fany , Cohen Nissim
Published: December 2014

This article introduces and explores two interesting phenomena: the phenomenon of alternative politics and attitudes toward the welfare state. The concept of alternative politics refers to a “do‐it‐yourself” approach where citizens on their own adopt extra‐legal, and often illegal, strategies to improve the services provided by the government. Through a theoretical framework and empirical model, we explore the extent to which attitudes toward alternative politics strategies are influenced by sociodemographic variables and attitudes toward the welfare state. The study utilizes the distinction between normative perceptions (imputed preferences) and induced preferences. We show that short‐term activities guided by the motivation of narrow self‐interests do not necessarily reflect public attitudes or the values and norms that people hold vis‐à‐vis the public sphere. This finding may reflect the (mis)interpretation that politicians and decision makers make by concluding that short‐term actions are indicative of long‐term attitudes.
Storing Fresh Produce for Fast Retrieval in an Automated Compact Cross‐Dock System
Authors: Zaerpour Nima , Yu Yugang , deKoster René B.M.
Published: December 2014

We study temporary storage of fresh produce in a cross‐dock center. In order to minimize cooling cost, compact storage systems are used. A major disadvantage of these systems is that additional retrieval time is needed, caused by necessary reshuffles due to the improper storage sequence of unit loads. In practice therefore, a dedicated storage policy is used in which every storage lane in the system accommodates only one product. However, this policy does not use the planned arrival time information of the outbound trucks. To exploit this information, this study proposes a mathematical model for a shared storage policy that minimizes total retrieval time. The policy allows different products to share the same lane. In order to solve real‐sized problems, an effective and efficient heuristic is proposed, based on a greedy construction and an improvement part, which provides near optimal solutions. The gaps between the results of the heuristic and the lower bound are mostly less than 1%. The resulting shared storage policy is generally robust against disturbances in arrival or departure times. We compare our shared storage heuristic with dedicated storage to determine which policy performs best under which circumstances. For most practical cases, shared storage appears to outperform dedicated storage, with a shorter response time and better storage lane utilization.
Up Then Down: Bid‐Price Trends in Revenue Management
Authors: Pang Zhan , Berman Oded , Hu Ming
Published: December 2014

In the classic revenue management (RM) problem of selling a fixed quantity of perishable inventories to price‐sensitive non‐strategic consumers over a finite horizon, the optimal pricing decision at any time depends on two important factors: consumer valuation and bid price. The former is determined exogenously by the demand side, while the latter is determined jointly by the inventory level on the supply side and the consumer valuations in the time remaining within the selling horizon. Because of the importance of bid prices in theory and practice of RM, this study aims to enhance the understanding of the intertemporal behavior of bid prices in dynamic RM environments. We provide a probabilistic characterization of the optimal policies from the perspective of bid‐price processes. We show that an optimal bid‐price process has an upward trend over time before the inventory level falls to one and then has a downward trend. This intertemporal up‐then‐down pattern of bid‐price processes is related to two fundamental static properties of the optimal bid prices: (i) At any given time, a lower inventory level yields a higher optimal bid price, which is referred to as the resource scarcity effect; (ii) Given any inventory level, the optimal bid price decreases with time; that is referred to as the resource perishability effect. The demonstrated upward trend implies that the optimal bid‐price process is mainly driven by the resource scarcity effect, while the downward trend implies that the bid‐price process is mainly driven by the resource perishability effect. We also demonstrate how optimal bid price and consumer valuation, as two competing forces, interact over time to drive the optimal‐price process. The results are also extended to the network RM problems.
Predicting Political Influence on State Ethics Commissions: Of Course We Are Ethical—Nudge Nudge, Wink Wink
Authors: Rauh Jonathan
Published: December 2014

This article explores the ability of elected officials to affect the autonomy of state ethics commissions. The author examines autonomy as a function of the capacity of ethics commissions to control their finances and personnel decisions and how the presence or absence of that capacity affects whether bureaucratic structures can function independently of politics. Using data from the 2011 State Integrity Investigation, the analysis extends previous arguments concerning political actors’ desire to affect ethics commissions. Findings suggest that elected officials use their positions to control the makeup of commission leadership and financial resources, with the goal of decreasing commissions’ ability to act autonomously.
Portfolio Analysis of Layered Security Measures
Authors: Chatterjee Samrat , Hora Stephen C. , Rosoff Heather
Published: December 2014

Layered defenses are necessary for protecting the public from terrorist attacks. Designing a system of such defensive measures requires consideration of the interaction of these countermeasures. In this article, we present an analysis of a layered security system within the lower Manhattan area. It shows how portfolios of security measures can be evaluated through portfolio decision analysis. Consideration is given to the total benefits and costs of the system. Portfolio diagrams are created that help communicate alternatives among stakeholders who have differing views on the tradeoffs between security and economic activity.
The Effects of Urban Form on Ambient Air Pollution and Public Health Risk: A Case Study in Raleigh, North Carolina
Authors: Mansfield Theodore J. , Rodriguez Daniel A. , Huegy Joseph , MacDonald Gibson Jacqueline
Published: December 2014

Since motor vehicles are a major air pollution source, urban designs that decrease private automobile use could improve air quality and decrease air pollution health risks. Yet, the relationships among urban form, air quality, and health are complex and not fully understood. To explore these relationships, we model the effects of three alternative development scenarios on annual average fine particulate matter (PM2.5) concentrations in ambient air and associated health risks from PM2.5 exposure in North Carolina's Raleigh‐Durham‐Chapel Hill area. We integrate transportation demand, land‐use regression, and health risk assessment models to predict air quality and health impacts for three development scenarios: current conditions, compact development, and sprawling development. Compact development slightly decreases (−0.2%) point estimates of regional annual average PM2.5 concentrations, while sprawling development slightly increases (+1%) concentrations. However, point estimates of health impacts are in opposite directions: compact development increases (+39%) and sprawling development decreases (−33%) PM2.5‐attributable mortality. Furthermore, compactness increases local variation in PM2.5 concentrations and increases the severity of local air pollution hotspots. Hence, this research suggests that while compact development may improve air quality from a regional perspective, it may also increase the concentration of PM2.5 in local hotspots and increase population exposure to PM2.5. Health effects may be magnified if compact neighborhoods and PM2.5 hotspots are spatially co‐located. We conclude that compactness alone is an insufficient means of reducing the public health impacts of transportation emissions in automobile‐dependent regions. Rather, additional measures are needed to decrease automobile dependence and the health risks of transportation emissions.
On the Effectiveness of Security Countermeasures for Critical Infrastructures
Authors: Hausken Kjell , He Fei
Published: December 2014

A game‐theoretic model is developed where an infrastructure ofNtargets is protected against terrorism threats. An original threat score is determined by the terrorist's threat against each target and the government's inherent protection level and original protection. The final threat score is impacted by the government's additional protection. We investigate and verify the effectiveness of countermeasures using empirical data and two methods. The first is to estimate the model's parameter values to minimize the sum of the squared differences between the government's additional resource investment predicted by the model and the empirical data. The second is to develop a multivariate regression model where the final threat score varies approximately linearly relative to the original threat score, sectors, and threat scenarios, and depends nonlinearly on the additional resource investment. The model and method are offered as tools, and as a way of thinking, to determine optimal resource investments across vulnerable targets subject to terrorism threats.
The Choice of Dialysate Sodium is Influenced by Hemodialysis Frequency and Duration: What Should It Be and For What Modality?
Authors: Thomson Benjamin K. A. , Huang Shih‐Han S. , Lindsay Robert M.
Published: December 2014

Cardiovascular disease is the leading cause of mortality in hemodialysis patients. A chronic state of volume and pressure overload contributes, and central to this is the net sodium balance over the course of a hemodialysis. Of recent interest is the contribution of the dialysate sodium concentration (Dial‐Na+) to clinical outcomes. Abundant evidence confirms that in thrice‐weekly conventional hemodialysis, higher Dial‐Na+ associates with increased intradialytic weight gain, blood pressure, and cardiovascular morbidity and mortality. On the other hand, low Dial‐Na+ associates with intradialytic hypotension in the same patient population. However, the effect of Dial‐Na+ in short hours daily hemodialysis (SHD; often referred to as “quotidian” dialysis), or nocturnal dialysis (FHND) is less well studied. Increased frequency and duration of exposure to a diffusive sodium gradient modulate the way in which DPNa+ alters interdialytic weight gain, predialysis blood pressure, and intradialytic change in blood pressure. Furthermore, increased dialysis frequency appears to decrease the predialysis plasma sodium setpoint (SP), which is considered stable in conventional thrice‐weekly patients. This review discusses criteria to determine optimal Dial‐Na+ in conventional, SHD and FHND patients, and identifies areas for future research.
US Wage Inequality and Low‐Wage Import Competition
Authors: Rigby David , Kemeny Tom , Cooke Abigail
Published: December 2014

This paper revisits the link between trade and wage inequality motivated by two changes in the structure of trade. First, trade today is shaped as much by the exchange of components as finished goods. Second, low‐wage country imports into advanced economies like the US have risen dramatically since the early 1990s. We pay special attention to the timing of trade impacts. Consistent with prior work, technological change is confirmed as the key driver of inequality before 1990. After 1990 the growth of wage inequality is primarily a consequence of rising import competition from low‐wage economies. We account for the growing fragmentation of production using a panel model focusing on within rather than between‐industry shifts in inequality. Lags of key variables are used as instruments, and our results appear robust to broad concerns with endogeneity and to different measures of skill‐biased technological change.
Chronic wound repair and healing in older adults: Current status and future research
Authors: Gould Lisa , Abadir Peter , Brem Harold , Carter Marissa , Conner‐Kerr Teresa , Davidson Jeff , DiPietro Luisa , Falanga Vincent , Fife Caroline , Gardner Sue , Grice Elizabeth , Harmon John , Hazzard William R. , High Kevin P. , Houghton Pamela , Jacobson Nasreen , Kirsner Robert S. , Kovacs Elizabeth J. , Margolis David , McFarland Horne Frances , Reed May J. , Sullivan Dennis H. , Thom Stephen , Tomic‐Canic Marjana , Walston Jeremy , Whitney JoAnne , Williams John , Zieman Susan , Schmader Kenneth
Published: December 2014

The incidence of chronic wounds is increased among older adults, and the impact of chronic wounds on quality of life is particularly profound in this population. It is well established that wound healing slows with age. However, the basic biology underlying chronic wounds and the influence of age‐associated changes on wound healing are poorly understood. Most studies have used in vitro approaches and various animal models, but observed changes translate poorly to human healing conditions. The impact of age and accompanying multi‐morbidity on the effectiveness of existing and emerging treatment approaches for chronic wounds is also unknown, and older adults tend to be excluded from randomized clinical trials. Poorly defined outcomes and variables, lack of standardization in data collection, and variations in the definition, measurement, and treatment of wounds also hamper clinical studies. The Association of Specialty Professors, in conjunction with the National Institute on Aging and the Wound Healing Society, held a workshop, summarized in this paper, to explore the current state of knowledge and research challenges, engage investigators across disciplines, and identify key research questions to guide future study of age‐associated changes in chronic wound healing.
On Risk-Based Design of Complex Engineering Systems: An Analytical Extreme Event Framework
Authors: Golbayani Hami , Kazerounian Kazem
Published: December 2014

In this work, a novel analytical framework is proposed for the risk-based design of complex engineering systems. The risk based-design process is the reverse process of risk propagation that entails the optimum allocation of the desired risk of failure of the system to all of its components. This paper studies the challenges in the design process of complex systems, the mathematical modeling of their topological architecture, and their unique behaviors. These characteristics make it impossible for the designer to use the common reliability and risk methodologies in the design process. The fundamental development of this work is an analytical upper bound for the distribution of risk of failure in the subsystem or element level. This upper bound satisfies the subadditivity condition of a coherent measure of risk. Additionally, its simplicity and low computational cost provide an appropriate framework as a fundamental building block for the risk-based design of complex systems. The proposed methodology is applied to three examples with insignificant desired probability of failure and its accuracy is compared with the Monte Carlo simulation, demonstrating its effectiveness and value.
Infrastructure Decay Modeling With the Input-Output Inoperability Model
Authors: Valencia Vhance V. , Thal Alfred E. , Colombi John M. , Sitzabee William E.
Published: December 2014

Asset management and infrastructure interdependency concepts are found to be useful in the study of infrastructure decay. As such, infrastructure decay is modeled with the input-output inoperability model (IIM), which is a method of analysis that captures cascading effects of a disturbance in interdependent infrastructure systems. This paper presents an extension to the IIM that simplifies the construction of the interdependency matrix central to the model and integrates the use of component decay curves for each component in the system. The revised model results in the ability of infrastructure asset managers to recognize the effect of decay across an entire infrastructure network or multiple networks.
Modeling and Simulations of the Supercavitating Vehicle With Its Tail-Slaps
Authors: Zou Wang , Liu Hua
Published: December 2014

It is one of the most important stable motion modes to move with tail-slaps for supercavitating vehicle. The periodical tail-slaps provide lift and restoring moment to keep a dynamic equilibrium of the vehicle. Research on the mode is significant to the stability and controllability of supercavity and its vehicle. The effect of the tail-slaps on supercavity is modeled to establish a supercavity model, combining with effects of gravity and angle of attack (AOA). Hydrodynamic forces acting on the vehicle are also formulated in the longitudinal plane based on the supercavity model and rigid body dynamics, considering its tail-slaps and control surfaces. The vehicle, which has a fixed periodical tail-slap, is simulated to calculate its hydrodynamic forces at a constant horizontal speed for different maximum pitch angles using the cavitation number embedded coefficient correction algorithm. The supercavity model is finally verified to some extent by comparing numerical results with experimental ones.