bluuebunny/crossref_metadata_2025 huggingface dataset:
Scintillation characteristics of LiCaAlF6-based single crystals under X-ray excitation
Authors: Nikl M. , Bruza P. , Panek D. , Vrbova M. , Mihokova E. , Mares J. A. , Beitlerova A. , Kawaguchi N. , Fukuda K. , Yoshikawa A.
Published: April 2013

LiCaAlF6-based scintillators are studied under X- and soft gamma-ray excitations. Under nanosecond pulsed soft X-ray laser excitation the scintillation decay is measured with extremely high dynamical resolution and broad time scale. The undoped LiCaAlF6 shows complex temperature dependence of exciton luminescence and tunneling-driven energy transfer process in scintillation decay. In both the Ce and Eu-doped LiCaAlF6 the dominant part of measured scintillation decay is due to prompt recombination of electrons and holes at the doped emission centers. Nevertheless, the measured light yield value is considerably lower with respect to the derived upper limits. Possible origin of its deterioration is discussed.
Band offsets of La2O3 on (0001) GaN grown by reactive molecular-beam epitaxy
Authors: Ihlefeld Jon F. , Brumbach Michael , Atcitty Stanley
Published: April 2013

La2O3 films were prepared on (0001)-oriented GaN substrates via reactive molecular-beam epitaxy. Film orientation and phase were assessed using reflection high-energy electron and X-ray diffraction. Films were observed to grow as predominantly hexagonal La2O3 for thicknesses less than 10 nm while film thickness greater than 10 nm favored mixed cubic and hexagonal symmetries. Band offsets were characterized by X-ray photoelectron spectroscopy on hexagonally symmetric films and valence band offsets of 0.63 ± 0.04 eV at the La2O3/GaN interface were measured. A conduction band offset of approximately 1.5 eV could be inferred from the measured valence band offset.
A Short Line Segment Squirms Along a Zigzag Line
Authors: Ito Hiroyuki , Yang Xie
Published: April 2013

When a short straight line segment moves across a zigzag line and is viewed in one's peripheral vision, it appears to exhibit nonrigid squirming motion (the squirm effect). This phenomenon demonstrates that the form, orientation, and motion direction of a short line are influenced by those of a longer one when they are viewed in one's peripheral vision.
Reproductive technologies for the future: a role for epigenetics
Authors: Walker Caroline G. , Mitchell Murray D.
Published: April 2013

Epigenetic mechanisms, such as DNA methylation, regulate gene expression and, subsequently, phenotype, without changing the underlying DNA sequence. It is well established that the environment and nutrition can regulate methylation and, therefore, modify phenotype. In this review, regulation of DNA methylation and in particular, the influence of B-vitamin on one-carbon metabolism is outlined, and how deficiency or supplementation with B-vitamins, such as folate, can influence disease. Evidence is provided for the roles of B-vitamin in regulating reproduction and how deficiency of B-vitamin may be impacting dairy cattle fertility. Results from our laboratory provide evidence for an association between DNA methylation and gene expression in the endometrium during early pregnancy. It is, therefore, hypothesised that DNA methylation may regulate the uterine response to the embryo during early pregnancy and that aberrant DNA methylation during this time may jeopardise pregnancy success. Further research is required to establish if B-vitamin supplementation can improve reproductive success and if this effect is via changes to DNA methylation and gene expression in the endometrium, or via positive effects on oocyte and embryo development.
Interactive effects of boron and NaCl stress on water and nutrient transport in two broccoli cultivars
Authors: del Carmen Rodríguez-Hernández María , Moreno Diego A. , Carvajal Micaela , del Carmen Martínez Ballesta María
Published: April 2013

In arid regions, the water from aquifers usually contains high NaCl levels, and alternative water sources, such as desalination plants, produce boron accumulation and have an adverse effect on crops. We studied the water transport and membrane integrity of two broccoli (Brassica oleracea L.) cultivars (Naxos and Viola) in the response to two boric acid levels, (1.8 mg L–1 and 4.3 mg L–1), alone or in combination with salinity (0 or 80 mM), and the involvement of plasma membrane intrinsic protein (PIP) aquaporins in this response. Nutritional status was also evaluated, as it affects the structural and functional integrity of the membranes. Since B is partly responsible for changes in the concentration and metabolism of phenolic compounds in vascular plants, these compounds were determined. In Naxos, the effect of 1.8 mg L–1 B concentration on the plasma membrane influenced plant salinity tolerance through the associated changes in the root hydraulic conductivity and the recovery of biomass production with regard to the NaCl treatment. By contrast, in Viola, a different PIP abundance pattern was observed indicating that the threshold B concentration differs between Viola and Naxos, resulting in higher sensitivity. In fact, a decreased transpiration and photosynthetic rate observed in Viola after the addition of 4.3 mg L–1 boric acid highlighted the highest sensitivity to boron, although this level had no adverse effect on the plasma membrane. The results suggest that B and NaCl trigger a hydric response involving aquaporins, together with changes in nutrient transport and plasma membrane stability.
Distribution and trend in abundance of the porbeagle (Lamna nasus) in the southern hemisphere
Authors: Semba Yasuko , Yokawa Kotaro , Matsunaga Hiroaki , Shono Hiroshi
Published: April 2013

Knowledge of a species’ distribution is an important element in its effective management and conservation. The porbeagle (Lamna nasus) is a common by-catch shark in the tuna longline fishery in the southern hemisphere, but its distribution and abundance are largely unknown. The investigation of observer data from the tuna longline fishery and other fishery survey data has revealed that (1) porbeagles are distributed in the pelagic waters across the oceans of the southern hemisphere, (2) juveniles and adults are distributed in cooler environments than are neonates, (3) pregnant females occur in the pelagic waters of the Indian Ocean and the Tasman Sea, most being frequently recorded around the Cape of Good Hope between June and July and (4) the standardised catch per unit effort (CPUE) based on tuna longline fishery (1994–2011) and driftnet survey (1982–1990) data indicate no continuous decreasing trend in the abundance of the southern porbeagle, contrary to the declining trend reported in a limited region in the South Atlantic. Considering its circumglobal distribution, stock status of this population should be assessed using information from the areas of its major distribution, including pelagic waters, and international coordination across oceans is necessary for the effective management of this population.
Surveys of white sharks (Carcharodon carcharias) off bathing beaches in Algoa Bay, South Africa
Authors: Dicken M. L. , Booth A. J.
Published: April 2013

The present study provides information on the existence of a possible inshore nursery area for white sharks (Carcharodon carcharias) in Algoa Bay, South Africa. In total, 43 flights were conducted, using a Robinson R22 helicopter, between October 2010 and March 2012. A total of 50 white sharks was sighted, with a maximum sighting rate of seven sharks per hour in October 2010. The majority (96.0%) of sharks observed were less than 2.5 m in length, immature and sighted between October and March (98.0%). A hurdle model, comprising a logistic regression to model presence–absence and a log-normal generalised linear model for abundance showed that water temperature and barometric pressure explained the sightings of sharks, peaking in mid-December. The sighting of sharks was best explained by barometric pressure, month and year. A total of 58 white shark catches was recorded from key informant interviews with shore anglers between July 2009 and December 2011. Sharks ranged in size from 1.5 to 2.5 m in total length, with young-of-the-year sharks (<1.75 m) accounting for 69.0% of the catch. Defining key habitats for young-of-the-year and juveniles is critical for the management and conservation of white sharks worldwide.
Heterosexual partner acquisition rates in the Australian population
Authors: Tothill Nicholas F. H. , Smith Anthony M. A. , Regan David G.
Published: April 2013

The rate of partner acquisition in a population is an important parameter when constructing epidemiological models of sexually transmissible infections. We have analysed the results of a survey of the sexual behaviour of the Australian population to estimate how many people have acquired no new partner, one, two or at least three new partners in the past year, and hence estimated heterosexual partner acquisition rates for the population by gender and age band. Partner acquisition rates are ~0.5 new partners per year for 16- to 19-year-olds, peak at ~0.7 in the 20- to 24-year-old age band, and then decline steadily with age to ~0.2 per year. In all age bands, there are more male respondents reporting three or more new partners in the last year than what is consistent with the rest of the data, which could be interpreted as evidence of an additional population stratum characterised by higher partner acquisition rates.
E4orf4 induces PP2A- and Src-dependent cell death in
Drosophila melanogaster
and at the same time inhibits classic apoptosis pathways
Authors: Pechkovsky Antonina , Lahav Maoz , Bitman Eliya , Salzberg Adi , Kleinberger Tamar
Published: April 2013

Significance

Expression of the adenovirus protein E4orf4 alone in cultured mammalian cells prompts noncanonical apoptosis that is more efficient in oncogene-transformed cells than in normal cells. Here, E4orf4 activity in a whole organism (
Drosophila melanogaster
) is described, leading to three significant conclusions: (
i
) E4orf4-induced cell death is an evolutionarily conserved process; (
ii
) E4orf4 induces a distinctive mode of cell death, differing from well-characterized cell death mechanisms; and (
iii
) E4orf4 activates cell death but concomitantly inhibits it, thus minimizing damage to normal tissues. The last finding suggests a possible explanation for the differential effect of E4orf4 in normal and cancer cells.
Organic-matter loading determines regime shifts and alternative states in an aquatic ecosystem
Authors: Sirota Jennie , Baiser Benjamin , Gotelli Nicholas J. , Ellison Aaron M.
Published: April 2013

Slow changes in underlying state variables can lead to “tipping points,” rapid transitions between alternative states (“regime shifts”) in a wide range of complex systems. Tipping points and regime shifts routinely are documented retrospectively in long time series of observational data. Experimental induction of tipping points and regime shifts is rare, but could lead to new methods for detecting impending tipping points and forestalling regime shifts. By using controlled additions of detrital organic matter (dried, ground arthropod prey), we experimentally induced a shift from aerobic to anaerobic states in a miniature aquatic ecosystem: the self-contained pools that form in leaves of the carnivorous northern pitcher plant,Sarracenia purpurea. In unfed controls, the concentration of dissolved oxygen ([O2]) in all replicates exhibited regular diurnal cycles associated with daytime photosynthesis and nocturnal plant respiration. In low prey-addition treatments, the regular diurnal cycles of [O2] were disrupted, but a regime shift was not detected. In high prey-addition treatments, the variance of the [O2] time series increased until the system tipped from an aerobic to an anaerobic state. In these treatments, replicate [O2] time series predictably crossed a tipping point at ∼45 h as [O2] was decoupled from diurnal cycles of photosynthesis and respiration. Increasing organic-matter loading led to predictable changes in [O2] dynamics, with high loading consistently driving the system past a well-defined tipping point. TheSarraceniamicroecosystem functions as a tractable experimental system in which to explore the forecasting and management of tipping points and alternative regimes.
Serum microRNA-122 level correlates with virologic responses to pegylated interferon therapy in chronic hepatitis C
Authors: Su Tung-Hung , Liu Chen-Hua , Liu Chun-Jen , Chen Chi-Ling , Ting Te-Tien , Tseng Tai-Chung , Chen Pei-Jer , Kao Jia-Horng , Chen Ding-Shinn
Published: April 2013

MicroRNA-122 (miR-122) facilitates hepatitis C virus replication in vitro. Serum miR-122 has been implicated as a biomarker for various liver diseases; however, its role in chronic hepatitis C remains unclear. To address this issue, 126 patients with chronic hepatitis C who completed pegylated IFN plus ribavirin therapy with sustained virologic response (SVR) or nonresponse (NR) were retrospectively included, and their pretreatment clinical profiles and treatment responses were collected. Serum miR-122 was quantified before and during treatment. Another 51 patients in SVR and NR groups were prospectively enrolled for validation. Serum miR-122 was found to be a surrogate for hepatic miR-122 and positively correlated with hepatic necroinflammation. Patients who showed complete early virologic response and SVR had significantly higher pretreatment serum miR-122 levels than those with NR (
P
= 0.001 and
P
= 0.008, respectively), especially in subgroups of patients with hepatitis C virus genotype 2 and IL-28B rs8099917 TT genotype. Patients with IL-28B TT genotype had significantly better treatment responses and higher pretreatment serum miR-122 level than those with GT or GG genotypes. Univariate analysis showed that pretreatment body mass index, γ-glutamyl transpeptidase, triglyceride, IL-28B TT genotype, and serum miR-122 are predictors for SVR. Multivariate analysis specifically in IL-28B TT genotype demonstrated that pretreatment serum miR-122 independently predicted SVR. The validation cohort confirmed a significantly greater pretreatment serum miR-122 level in patients with SVR compared with NR (
P
= 0.025). In conclusion, serum miR-122 may serve as a surrogate of hepatic miR-122, and a higher pretreatment serum miR-122 level can help predict virologic responses to pegylated IFN plus ribavirin therapy.
Autocrine signaling based selection of combinatorial antibodies that transdifferentiate human stem cells
Authors: Xie Jia , Zhang Hongkai , Yea Kyungmoo , Lerner Richard A.
Published: April 2013

We report here the generation of antibody agonists from intracellular combinatorial libraries that transdifferentiate human stem cells. Antibodies that are agonists for the granulocyte colony stimulating factor receptor were selected from intracellular libraries on the basis of their ability to activate signaling pathways in reporter cells. We used a specialized “near neighbor” approach in which the entire antibody library and its target receptor are cointegrated into the plasma membranes of a population of reporter cells. This format favors unusual interactions between receptors and their protein ligands and ensures that the antibody acts in an autocrine manner on the cells that produce it. Unlike the natural granulocyte-colony stimulating factor that activates cells to differentiate along a predetermined pathway, the isolated agonist antibodies transdifferentiated human myeloid lineage CD34+ bone marrow cells into neural progenitors. This transdifferentiation by agonist antibodies is different from more commonly used methods because initiation is agenetic. Antibodies that act at the plasma membrane may have therapeutic potential as agents that transdifferentiate autologous cells.
Effects of Simulated Angler Capture and Live‐Release Tournaments on Walleye Survival
Authors: Loomis John H. , Schramm Harold L. , Vondracek Bruce , Gerard Patrick D. , Chizinski Christopher J.
Published: April 2013

We examined the effects of acclimation water temperature,live‐well (LW) water temperature,and LW dissolved oxygen (DO) concentration on survival of adult Walleyes Sander vitreus subjected to simulated tournament conditions (angling,LW confinement,and weigh‐in procedures) under controlled laboratory conditions. We tested three acclimation temperatures (12,18,and 24°C),and three LW temperature differentials (ΔT = −4,0,and +4°C) were tested at each acclimation temperature. Survival was monitored after 8 h of LW confinement and during a 5‐d retention period in 1,700‐L tanks. None of the Walleyes that were acclimated to 24°C and subjected to simulated tournament procedures survived the 5‐d retention period; for fish subjected only to simulated angling at 24°C,survival during the 5‐d retention period was 29%. Five‐day survival was generally over 70% at acclimation temperatures of 12°C and 18°C,and we observed a significant interaction between acclimation temperature and ΔT; survival was greatest in LWs at −4°C ΔT for fish acclimated to 18°C and in LWs at +4°C ΔT for fish acclimated to 12°C. Best survival of Walleyes subjected to the stress of angling and tournament procedures was obtained at temperatures 6–8°C below the optimum temperature for adult Walleyes (i.e.,optimum = 20–22°C). Five‐day survival exceeded 70% when LW DO was 5 or 12–15 mg/L (at an acclimation and LW temperature of 18°C),but survival was 0% when DO was 2 mg/L. Anglers may increase survival of Walleyes through careful manipulation of LW temperature and DO when ambient temperature is at or below 18°C,but high mortality of angled and LW‐retained Walleyes should be expected when ambient water temperatures are 24°C or greater.
Collective Identity and Despotism: Lessons in Two Plays by Bahram Beyzaie
Authors: Ghanoonparvar M. R.
Published: April 2013

With an overview of identity as a dominant theme in Bahram Beyzaie's artistic creations, this article examines two of his, arguably, most political plays: Chahar Sanduq (Four Boxes, 1967) and Khaterat-e Honarpisheh-ye Naqsh-e Dovvom (Memoirs of the Actor in a Supporting Role, 1981) to examine his reflections on the nature, function, and vulnerability of collective social, political, and cultural identity in authoritarian societies. Both plays illustrate that the tyrannical rulers of such societies perpetuate their dominance over their subjects through exploiting the individual's self-interests, thereby isolating him and stripping him of collective and, inevitably, individual identity. Beyzaie's allegorical and rather abstract approach in these plays contributes to conveying a less topical, culture-specific, and more universal message.
Array Training in a Categorization Task
Authors: Homa Donald , Powell Derek , Ferguson Ryan
Published: April 2013

Two components of categorization, within-category commonalities and between-category distinctiveness, were investigated in a categorization task. Subjects learned three prototype categories composed of moderately high distortions, by observing arrays containing patterns that belonged either to a common prototype category or to three different categories; a third group learned patterns presented one at a time, mirroring the standard paradigm. Following 6 learning blocks, subjects transferred to old patterns and new patterns at low-, medium-, and high-level distortions of the category prototype. The results showed that array training facilitated learning, especially when patterns in the array belonged to the same category. Transfer results showed a strong gradient effect across pattern distortion level for all conditions, with the highest performance obtained following array training on different category patterns and worst in the control condition. Interestingly, the old training patterns were classified worse than new low and no better than medium distortions. Neither this ordering nor the steepness of the gradient across prototype similarity for each condition could be predicted by the generalized context model. A prototype model better captured the steep gradient and ordinal pattern of results, although the overall fits were only slightly better than the exemplar model. The crucial role played by category commonalities and distinctiveness on categorical representations is addressed.
On the Metaphorical Connectivity of Cultural Sign Systems
Authors: Danesi Marcel
Published: April 2013

Theories of culture based on signs and systems are found across the interdisciplinary spectrum. There seems to be a growing consensus across disciplines that the forms of culture (linguistic, material, aesthetic, ritualistic, etc.) are connected to each other in some way. With the advent of conceptual metaphor theory, this article claims that the cognitive mechanism (metaphor) connecting the forms can be found in this theoretical framework. It also puts forward the notion of metaform as a nonverbal counterpart to a conceptual metaphor. In this way, it is possible to link signs and systems to each other into a network of distributed meanings that constitute a culture.
Citation and Citationality
Authors: Nakassis Constantine V.
Published: April 2013

This essay explores the semiotics of citation. The citation is an act that re-presents some other event of discourse and marks that re-presentation as not(-quite) what it presences. The citation is a play of sameness and difference, identity and alterity, an interdiscursive calibration of an event of citing and a cited event, and is reflexive about that very fact. As such, citational acts can open up new social horizons of possibility, signification, and performative power. This essay investigates the citational underpinnings of the Fregean sense, Austinian performativity, and Derridean deconstruction. I give particular attention to Derrida's reading of Austin, and his development of the concept of citationality. As I argue, Derrida's insistence on the necessary possibility of citationality elides the fact that citations are always already achievements in context, and thus empirical facts about particular (types of) acts in the world. Not all acts are reflexive about their citationality, and this has consequences for their material form and their pragmatics. Finally, the essay turns to the recalcitrance of events of semiosis to being cited, in particular, to taboo speech. Taboo speech presents a case of speech that seemingly cannot be bracketed, where performative effect necessarily and always attains. As such cases show, citation brackets and suspends, but perhaps never totally.
Touching the Past: Materializing Time in Traumatic “Living History” Reenactments
Authors: Auslander Mark
Published: April 2013

Many living history reenactors speak of “touching the past” in their performances. In nearly all instances, these profound experiences of intimate traffic with previous epochs and persons are brought about not through physical contact with historical artifacts but through deployments of replicas and props, including recently produced adornment, weaponry, vehicles, and tools. This essay explores the roles and functions of material reproductions or substitutes of historic artifacts in reenactment performances, and how these object-oriented practices often bring about powerful sensations of historic authenticity on the part of reenactors and their audiences. I give particular attention to the use of physical objects by those who seek to reenact traumatic events and experiences related to American histories of racial injustice, including experiences of slavery and Jim Crow racial violence.
mapDamage2.0: fast approximate Bayesian estimates of ancient DNA damage parameters
Authors: Jónsson Hákon , Ginolhac Aurélien , Schubert Mikkel , Johnson Philip L. F. , Orlando Ludovic
Published: April 2013

Motivation: Ancient DNA (aDNA) molecules in fossilized bones and teeth, coprolites, sediments, mummified specimens and museum collections represent fantastic sources of information for evolutionary biologists, revealing the agents of past epidemics and the dynamics of past populations. However, the analysis of aDNA generally faces two major issues. Firstly, sequences consist of a mixture of endogenous and various exogenous backgrounds, mostly microbial. Secondly, high nucleotide misincorporation rates can be observed as a result of severe post-mortem DNA damage. Such misincorporation patterns are instrumental to authenticate ancient sequences versus modern contaminants. We recently developed the user-friendly mapDamage package that identifies such patterns from next-generation sequencing (NGS) sequence datasets. The absence of formal statistical modeling of the DNA damage process, however, precluded rigorous quantitative comparisons across samples.

Results: Here, we describe mapDamage 2.0 that extends the original features of mapDamage by incorporating a statistical model of DNA damage. Assuming that damage events depend only on sequencing position and post-mortem deamination, our Bayesian statistical framework provides estimates of four key features of aDNA molecules: the average length of overhangs (λ), nick frequency (ν) and cytosine deamination rates in both double-stranded regions () and overhangs (). Our model enables rescaling base quality scores according to their probability of being damaged. mapDamage 2.0 handles NGS datasets with ease and is compatible with a wide range of DNA library protocols.

Availability: mapDamage 2.0 is available at ginolhac.github.io/mapDamage/ as a Python package and documentation is maintained at the Centre for GeoGenetics Web site (geogenetics.ku.dk/publications/mapdamage2.0/).

Contact:  jonsson.hakon@gmail.com

Supplementary information:  Supplementary data are available at Bioinformatics online.
CellAging: a tool to study segregation and partitioning in division in cell lineages of Escherichia coli
Authors: Häkkinen Antti , Muthukrishnan Anantha-Barathi , Mora Andre , Fonseca Jose M. , Ribeiro Andre S.
Published: April 2013

Motivation: Cell division in Escherichia coli is morphologically symmetric. However, as unwanted protein aggregates are segregated to the cell poles and, after divisions, accumulate at older poles, generate asymmetries in sister cells’ vitality. Novel single-molecule detection techniques allow observing aging-related processes in vivo, over multiple generations, informing on the underlying mechanisms.

Results: CellAging is a tool to automatically extract information on polar segregation and partitioning in division of aggregates in E.coli, and on cellular vitality. From time-lapse, parallel brightfield and fluorescence microscopy images, it performs cell segmentation, alignment of brightfield and fluorescence images, lineage construction and pole age determination, and it computes aging-related features. We exemplify its use by analyzing spatial distributions of fluorescent protein aggregates from images of cells across generations.

Availability: CellAging, instructions and an example are available at http://www.cs.tut.fi/%7esanchesr/cellaging/.

Contact:  andre.ribeiro@tut.fi

Supplementary information:  Supplementary data are available at Bioinformatics online.
Marshall in Iberia. Industrial Districts and Leading Firms in the Creation of Competitive Advantage in Fashion Products
Authors: Catalan Jordi , Ramon-Muñoz Ramon
Published: April 2013

Firms dealing with “Made in Spain” fashion products (e.g., textiles, apparel, and footwear) have increased their presence in the world market over the last two decades. This paper focuses on the origins of this process. After constructing a new database of export districts, it first investigates the sources of the international competitiveness of these districts. Second, it explores whether industrial districts boosted the internationalization of Spanish fashion firms. The paper concludes that most of today’s outstanding Spanish firms in fashion-related international markets emerged from 1980s’ districts, which could have benefited from classical Marshallian externalities, while also taking advantage of the organizational capabilities of leading firms.
A predominance of hypertensive heart failure in the Abuja Heart Study cohort of urban Nigerians: a prospective clinical registry of 1515 de novo cases
Authors: Ojji Dike , Stewart Simon , Ajayi Samuel , Manmak Mamven , Sliwa Karen
Published: April 2013

Aims

Even though cardiovascular disease is gradually becoming the major cause of morbidity and mortality in sub‐Saharan Africa, there are very few data on the pattern of heart disease in this part of the world. We therefore decided to determine the pattern of heart disease in Abuja, which is one of the fastest growing and most westernized cities in Nigeria, and compare our findings with those of the Heart of Soweto Study in South Africa.

Methods and results

Detailed clinical data were consecutively captured from 1515 subjects of African descent, residing in Abuja, and equivalent Soweto data from 4626 subjects were available for comparison. In Abuja, male subjects were on average, ∼2 years older than female subjects. Hypertension was the primary diagnosis in 45.8% of the cohort, comprising more women than men [odds ratio (OR) 1.96, 95% confidence interval (CI) 1.26–2.65], and hypertensive heart failure (HF) was the most common form of HF in 61% of cases. On an age‐ and sex‐adjusted basis, compared with the Soweto cohort, the Abuja cohort were more likely to present with a primary diagnosis of hypertension (adjusted OR 2.10, 95% CI 1.85–2.42) or hypertensive heart disease/failure (OR 2.48, 95% CI 2.18–2.83); P < 0.001 for both. They were, however, far less likely to present with CAD (OR 0.04, 95% CI 0.02–0.11) and right heart failure (2.5% vs. 27%).

Conclusion

As in Soweto, but more so, hypertension is the most common cause of de novo HF presentations in Abuja, Nigeria.
The importance of accurate muscle modelling for biomechanical analyses: a case study with a lizard skull
Authors: Gröning Flora , Jones Marc E. H. , Curtis Neil , Herrel Anthony , O'Higgins Paul , Evans Susan E. , Fagan Michael J.
Published: April 2013

Computer-based simulation techniques such as multi-body dynamics analysis are becoming increasingly popular in the field of skull mechanics. Multi-body models can be used for studying the relationships between skull architecture, muscle morphology and feeding performance. However, to be confident in the modelling results, models need to be validated against experimental data, and the effects of uncertainties or inaccuracies in the chosen model attributes need to be assessed with sensitivity analyses. Here, we compare the bite forces predicted by a multi-body model of a lizard (Tupinambis merianae) within vivomeasurements, using anatomical data collected from the same specimen. This subject-specific model predicts bite forces that are very close to thein vivomeasurements and also shows a consistent increase in bite force as the bite position is moved posteriorly on the jaw. However, the model is very sensitive to changes in muscle attributes such as fibre length, intrinsic muscle strength and force orientation, with bite force predictions varying considerably when these three variables are altered. We conclude that accurate muscle measurements are crucial to building realistic multi-body models and that subject-specific data should be used whenever possible.
Functional Conservation of MIKC*-Type MADS Box Genes in Arabidopsis and Rice Pollen Maturation
Authors: Liu Yuan , Cui Shaojie , Wu Feng , Yan Shuo , Lin Xuelei , Du Xiaoqiu , Chong Kang , Schilling Susanne , Theißen Günter , Meng Zheng
Published: April 2013

There are two groups of MADS intervening keratin-like and C-terminal (MIKC)-type MADS box genes, MIKCC type and MIKC* type. In seed plants, the MIKCC type shows considerable diversity, but the MIKC* type has only two subgroups, P- and S-clade, which show conserved expression in the gametophyte. To examine the functional conservation of MIKC*-type genes, we characterized all three rice (Oryza sativa) MIKC*-type genes. All three genes are specifically expressed late in pollen development. The single knockdown or knockout lines, respectively, of the S-clade MADS62 and MADS63 did not show a mutant phenotype, but lines in which both S-clade genes were affected showed severe defects in pollen maturation and germination, as did knockdown lines of MADS68, the only P-clade gene in rice. The rice MIKC*-type proteins form strong heterodimeric complexes solely with partners from the other subclade; these complexes specifically bind to N10-type C-A-rich-G-boxes in vitro and regulate downstream gene expression by binding to N10-type promoter motifs. The rice MIKC* genes have a much lower degree of functional redundancy than the Arabidopsis thaliana MIKC* genes. Nevertheless, our data indicate that the function of heterodimeric MIKC*-type protein complexes in pollen development has been conserved since the divergence of monocots and eudicots, roughly 150 million years ago.
A cocrystal of two MoVIcomplexes bearing different diastereomers of the 2,4-di-tert-butyl-6-{[(1-oxido-1-phenylpropan-2-yl)(methyl)amino]methyl}phenolate ligand derived from (+)-ephedrine
Authors: Sillanpää Reijo , Hänninen Mikko M.
Published: April 2013

The title cocrystal contains two chiral conformational diastereomers,viz.(1S,2R,RN)- and (1S,2R,SN)-, of [2,4-di-tert-butyl-6-{[(1-oxido-1-phenylpropan-2-yl)(methyl)amino]methyl}phenolato](methanol)-cis-dioxidomolybdenum(VI), [Mo(C25H35NO2)O2(CH3OH)], representing the first example of a structurally characterized molybdenum complex with enantiomerically pure ephedrine derivative ligands. The MoVIcations exhibit differently distorted octahedral coordination environments, with two oxide ligands positionedcisto each other. The remainder of the coordination comprises phenoxide, alkoxide and methanol O atoms, with an amine N atom completing the octahedron. The distinct complexes are linked by strong intermolecular O—H...O hydrogen bonds, resulting in one-dimensional molecular chains. Furthermore, the phenyl rings are involved in weak T-shaped/edge-to-face π–π interactions with each other.
What's the ticker symbol for farmland?
Authors: Sherrick Bruce J. , Mallory Mindy L. , Hopper Timothy
Published: April 2013

Purpose

Relatively high recent returns to farmland investments have led to substantially elevated interest in farmland investments. Absent, however, is a well‐functioning equity market in farmland real estate, or well‐developed indexes of farmland returns that might contribute to the development of tradable shares tied to farmland returns, or to methods to hedge the value of owned agricultural assets. The purpose of this study is to empirically present relevant measures related to farmland returns and other financial assets to provide a broad context for evaluation of farmland investments in a portfolio context. Issues related to the development of a farmland fund and index construction are discussed along with major risk and transactional factors that are somewhat unique to the asset class.

Design/methodology/approach

Returns data from a broad set of financial categories and broad set of agricultural returns measures are developed and presented in multiple frameworks to convey temporal persistence, relatedness, and portfolio considerations related to farmland. Issues related to the construction of claims based on agricultural assets are discussed.

Findings

Agricultural real estate investments have performed well compared to most other financial assets on most traditional measures of risk adjusted performance. However, the difficulties in direct investment remain and the need to develop securitized conduit exposures to farmland returns is identified.

Originality/value

The study presents a unique set of farmland returns measures and examines the stability of the statistics used to describe these through time. Novel characterizations of the data compared to traditional assets helps investors and asset owners accurately understand the exposure to farmland returns.
Farmland rental markets: trends in contract type, rates, and risk
Authors: Paulson Nicholas D. , Schnitkey Gary D.
Published: April 2013

Purpose

This article aims to explore recent trends in farmland rental markets using data for the state of Illinois. Trends in the types of rental agreements used and the relationship between the rental rate for those contracts, land values, crop revenues, production costs, and farm returns are examined.

Design/methodology/approach

Data from various sources and at different levels of aggregation for the state of Illinois are used to provide illustrations of historical trends in farmland rental agreements and rental rates, and how they are related to various market and industry factors. Focus is placed on the more recent period since 2005 characterized by high commodity price levels and volatility.

Findings

The majority of farmland in the Midwest is controlled under rental agreements which are increasingly of the fixed cash rent type. Rental rates have increased, but at a slower rate than farm returns. Average rental and interest rates imply that land values are consistent with the current market environment. Aggregate rental rates mask considerable variation in farm‐level rents, only a portion of which can be explained by differences in soil productivity. Given the current level of price volatility, the tenure position of a farm operation has a significant effect on downside risk exposure.

Originality/value

The illustrations provided in this paper should be of interest to researchers working in the area of farmland values and rental agreements, as well as to practitioners including farmers, landowners, and professional farm managers. The findings should motivate additional research and recognition of the importance of tenure position to the performance and risk exposure of grain farms.
Financial performance of publicly‐traded agribusinesses
Authors: Katchova Ani L. , Enlow Sierra J.
Published: April 2013

Purpose

Agribusinesses represent a fundamental link in connecting farmers with retailers and consumers, yet little research has been done to examine the historical financial performance of these food processing firms. This paper aims to address this issue.

Design/methodology/approach

The authors' research examines how publicly‐traded agribusinesses perform financially compared to all firms over the period from 1961 to 2011. The authors utilize several indicators of company success, including financial ratios and balance sheet/income statement items, to compare agribusiness firms to all firms in the market. The authors perform the analysis over time and also for companies with low, median, and high performance. They also perform Du Pont analysis to compare return on equity components between agribusinesses and all firms.

Findings

The authors find that agribusinesses outperform at the median the sample of all firms in terms of financial ratios related to profitability, liquidity, and market ratios, but have slightly lower liquidity and debt ratios. The Du Pont analysis shows that the higher return on equity for agribusinesses is mostly due to higher asset turnover ratios, indicating higher operating efficiency of agribusinesses. The strong financial performance of food manufacturing agribusinesses makes them valuable companies in an investment portfolio.

Originality/value

This study provides a basic overview of financial ratios used to examine the financial performance of publicly‐traded agribusinesses. The authors' findings show that agribusinesses outperform all firms in terms of key financial indicators.
Accounting for short samples and heterogeneous experience in rating crop insurance
Authors: Borman Julia I. , Goodwin Barry K. , Coble Keith H. , Knight Thomas O. , Rejesus Rod
Published: April 2013

Purpose

The purpose of this paper is to be an academic inquiry into rating issues confronted by the US Federal Crop Insurance program stemming from changes in participation rates as well as the weighting of data to reflect longer‐run weather patterns.

Design/methodology/approach

The authors investigate two specific approaches that differ from those adopted by the Risk Management Agency, building upon standard maximum likelihood and Bayesian estimation techniques that consider parametric densities for the loss‐cost ratio.

Findings

Both approaches indicate that incorporating weights into the priors for Bayesian estimation can inform the distribution.

Originality/value

In most cases, the authors' results indicate that including weighting into priors for Bayesian estimation implied lower premium rates than found using standard methods.
Determinants of the patronage refund decision of Farm Credit System associations
Authors: Zhang Tianwei , Mallory Mindy , Barry Peter
Published: April 2013

Purpose

The authors aim to investigate what influences a Farm Credit System association to make a patronage refund payment. In particular, they seek to investigate what causes the regional heterogeneity in the patronage refund payment decision. It is unclear whether patronage refunds have been used more as a capital management tool or as a member recruitment and retention tool. This study aims to bring some clarity to this issue.

Design/methodology/approach

The authors use an empirical logistic model to estimate the probability of a positive patronage refund payment by a Farm Credit System association, controlling for variables related to the associations' balance sheet as reported in the associations' quarterly call reports.

Findings

The authors find there is evidence that Farm Credit Service associations use patronage refunds as a capital management tool, at least in part. However, they also find that there are still significant regional differences in the patronage refund payment decision even after controlling for variables affecting the associations' balance sheet. The authors conclude that this likely represents member heterogeneity in preferences for patronage refunds versus a discounted interest rate.

Originality/value

The present study is one of the few empirical papers to examine a broad panel of financial cooperatives. Because of this, the authors' paper provides valuable insight into the aggregate behavior of Farm Credit Service associations, particularly into whether they use patronage refunds as a capital management tool, or as a marketing and retention tool.
Agricultural lending and early warning models of bank failures for the late 2000s Great Recession
Authors: Li Xiaofei , Escalante Cesar L. , Epperson James E. , Gunter Lewell F.
Published: April 2013

Purpose

The late 2000s Great Recession led to a surge of bank failures in the USA with nearly 300 banks failing from 2009 to 2010. Recalling the farm crises of the 1980s where the farm sector was pinpointed as one of the major precursors of such crises, this study is an attempt to validate if the agricultural sector can once again be considered as a major instigator of the current financial crises.

Design/methodology/approach

An early warning model is developed based on factors that may cause bank failures, with special attention given to the role of the agricultural lending portfolios of commercial banks. The model will have several time period versions that will determine the length of time prior to the actual bank bankruptcy declarations that early warning signals could be detected.

Findings

The empirical results indicate that credit exposure to the farm sector does not necessarily enhance a bank's tendency to fail or its probability of success or survival. This lends support to the reality that agricultural loan delinquency rates are consistently below the banks' overall loan delinquency rates, thus confirming that agricultural lenders are in relatively stronger financial health. This study instead finds that costly funding arrangements, increasing interest rate risk, and declining asset quality can be possible early warning signals that can be detected as far back as two or three years before eventual bank failure.

Originality/value

This study differentiates itself from previous studies by its special focus on the role of the agricultural finance industry in the ensuing economic crises. This study's early warning model also presents an extended version of previous empirical models as it accounts for measures of capital adequacy, asset quality, management risk, profitability, liquidity risk, loan portfolio composition and risk, funding arrangement, structural and macroeconomic variables.
Weather risk management by Saskatchewan agriculture producers
Authors: Khan Saqib , Rennie Morina , Charlebois Sylvain
Published: April 2013

Purpose

The purpose of this research is to study the weather risk management practices of agriculture producers. In particular, the authors look at the extent to which farmers use weather derivatives to complement insurance. Unlike insurance, weather derivatives mitigate risk associated with low intensity, high probability events and therefore offer the potential of a more complete hedge than insurance alone.

Design/methodology/approach

The authors conducted a survey of grain farmers in the province of Saskatchewan, Canada, a typical jurisdiction in which farmers tend to face weather events that are high in frequency but low in severity, to study the usage of weather derivatives compared to insurance and identify the hurdles to their usage.

Findings

The authors find that fewer than 10 percent of their respondents use weather derivatives. Consistent with previous literature in other contexts, they identify participation costs, especially lack of awareness, to be the most significant hurdle to their usage.

Research limitations/implications

A limitation of this study is that the data were collected using a survey methodology and are therefore subject to the usual risks of bias associated with that approach. Moreover, because the authors' survey was delivered online, it may have favoured the participation of farmers that were more comfortable with technology and some bias may have also been introduced into the data as a result.

Practical implications

The authors' findings suggest that there is significant potential to improve farmers' ability to hedge weather risk and thereby improve economic outcomes if the major barriers to the usage of weather derivatives can be overcome. The study paves the way for further research to support the development of public policy strategies that could help farmers take advantage of weather derivatives as part of their inventory of risk management tools.

Originality/value

To the authors' knowledge this is the first study that quantifies the usage of weather derivatives by agriculture producers and identifies the hurdles.
Testing for speculative bubbles in agricultural commodity prices: a regime switching approach
Authors: Liu Xiaoliang , Filler Guenther , Odening Martin
Published: April 2013

Purpose

The authors' paper aims to deal with the question whether speculative bubbles are present in agricultural commodity prices.

Design/methodology/approach

The authors apply a regime switching regression model to test the hypothesis that agricultural prices contain periodically collapsing bubbles. Using daily futures prices for six agricultural commodities, the authors calculate net convenience yields from which price fundamentals are derived.

Findings

The authors discover pronounced deviations between observed prices and their fundamental values. However, they do not find evidence for the presence of periodically and partially collapsing speculative bubbles for five of six commodities. Except for soybeans, the signs and the significance of the estimated coefficients are not entirely in line with the predictions of the theoretical model.

Originality/value

The authors' study adds to the heated discussion on the impact of speculative behavior on agricultural commodity prices. So far, most contributions in the literature either use theoretical arguments for the (non‐) existence of bubbles or apply indirect tests which are plagued by low statistical reliability. In contrast, the authors apply a direct test. They find that the outcome of empirical bubble tests depends on the considered bubble type and on the testing procedure. In view of these ambiguities, definite statements on the presence of speculative bubbles as well as demands for limitations of speculative positions in commodity futures markets should be carefully reconsidered.