bluuebunny/crossref_metadata_2025 huggingface dataset:
Sex, outcrossing and mating types: unsolved questions in fungi and beyond
Authors: BILLIARD S. , LÓPEZ‐VILLAVICENCIO M. , HOOD M. E. , GIRAUD T.
Published: April 2012

Variability in the way organisms reproduce raises numerous, and still unsolved, questions in evolutionary biology. In this study, we emphasize that fungi deserve a much greater emphasis in efforts to address these questions because of their multiple advantages as model eukaryotes. A tremendous diversity of reproductive modes and mating systems can be found in fungi, with many evolutionary transitions among closely related species. In addition, fungi show some peculiarities in their mating systems that have received little attention so far, despite the potential for providing insights into important evolutionary questions. In particular, selfing can occur at the haploid stage in addition to the diploid stage in many fungi, which is generally not possible in animals and plants but has a dramatic influence upon the structure of genetic systems. Fungi also present several advantages that make them tractable models for studies in experimental evolution. Here, we briefly review the unsolved questions and extant hypotheses about the evolution and maintenance of asexual vs. sexual reproduction and of selfing vs. outcrossing, focusing on fungal life cycles. We then propose how fungi can be used to address these long‐standing questions and advance our understanding of sexual reproduction and mating systems across all eukaryotes.
Constant, cycling, hot and cold thermal environments: strong effects on mean viability but not on genetic estimates
Authors: KETOLA T. , KELLERMANN V. , KRISTENSEN T. N. , LOESCHCKE V.
Published: April 2012

It has frequently been suggested that trait heritabilities are environmentally sensitive, and there are genetic trade‐offs between tolerating different environments such as hot and cold or constant and fluctuating temperatures. Future climate predictions suggest an increase in both temperatures and their fluctuations. How species will respond to these changes is uncertain, particularly as there is a lack of studies which compare genetic performances in constant vs. fluctuating environments. In this study, we used a nested full‐sib/half‐sib breeding design to examine how the genetic variances and heritabilities of egg‐to‐adult viability differ at high and low temperatures with and without daily fluctuations in temperatures usingDrosophila melanogasteras a model organism. Although egg‐to‐adult viability was clearly sensitive to developmental temperatures, heritabilities were not particularly sensitive to developmental temperatures. Moreover, we found that egg‐to‐adult viabilities at different developmental temperatures were positively correlated, suggesting a common genetic background for egg‐to‐adult viability at different temperatures. Finding both a uniform genetic background coupled with rather low heritabilities insensitive to temperatures, our results suggest evolutionary responses are unlikely to be limited by temperature effects on genetic parameters or negative genetic correlations, but by the direct effects of stressful temperatures on egg‐to‐adult viability accompanied with low heritabilities.
Sequence Diversity in the NSm Gene of Groundnut Bud Necrosis Virus Isolates Originating from Different Hosts and Locations in India
Authors: Akram Mohammad , Naimuddin Kamaal , Jain Rakesh K.
Published: April 2012

The movement protein (NSm) gene of Groundnut bud necrosis virus (GBNV) isolates from pea, mungbean, cowpea, French bean, tomato and potato collected from different locations of India were compared to study their diversity. The NSm gene sequences of all the GBNV isolates were highly conserved and had only 0–3% diversity in amino acids and 0–10% in nucleotides. Comparison of amino acid sequence of NSm gene of 25 GBNV isolates revealed the presence of many conserved regions. Both ‘D‐motif’ and ‘G‐residue’, the conserved regions of ‘30K superfamily’ of virus movement protein, were present in all the isolates. Clustering of the GBNV isolates does not appear to be based on their place of origin and host plant species.
Current Status of Fig Mosaic Disease in Iran
Authors: Shahmirzaie Morteza , Rakhshandehroo Farshad , Zamanizadeh Hamid Reza , Elbeaino Toufic
Published: April 2012

During 2009–2010, a survey was conducted in gardens and commercial fig orchards throughout Iran to determine the prevalence of Fig leaf mottle‐associated virus 1 (FLMaV‐1), Fig leaf mottle‐associated virus 2 (FLMaV‐2), Fig mild mottle‐associated virus (FMMaV), Fig latent virus 1 (FLV‐1) andFig mosaic virus(FMV). Reverse transcription‐polymerase chain reaction and dot immunobinding assay (DIBA) were conducted on 104 fig samples collected from seven provinces. FLV‐1, FLMaV‐1 and FMV were found in 14.5, 11.5 and 8.6% of the samples, respectively, but FLMaV‐2 and FMMaV were absent. The overall average of infection reached 18.3%, with a peak of 42.9% in Semnan Province, followed by Golestan (40%), Tehran (32.3%), Lorestan (28.6%) and Mazandaran (25%) provinces. No infection was found in Fars and Gilan provinces. Fig samples from Varamin and Khorramabad districts showed high levels of mixed infections, 35.7 and 28.6%, respectively. The presence of FMV and FLV‐1 in the sap of symptomatic fig leaves was also ascertained by DIBA. Sequence analysis of amplified DNA from the partial RNA‐dependent RNA polymerase gene of two FMV isolates from Iran showed a low level of nucleotide variability (5%). The Iranian isolates shared a common phylogeny with other Mediterranean FMV isolates and in particular with those originating from Turkey already reported in GenBank. This is the first report on the presence of FLMaV‐1 and FLV‐1 in Iran and offers a preliminary insight into the unsatisfactory health status of fig in this country.
“Is it effective?” to “How to use it?”: the era has changed in probiotics and functional food products against Helicobacter pylori infection
Authors: Matsushima Masashi , Takagi Atsushi
Published: April 2012

See article in J. Gastroenterol. Hepatol. 2012; 27: 888–892.
Is the dendritic cell a missing piece in the pathogenesis model of post‐infectious irritable bowel syndrome?
Authors: Hisamatsu Tadakazu , Hibi Toshifumi
Published: April 2012

See article in J. Gastroenterol. Hepatol. 2012; 27: 935–944.
Maternal and infant characteristics by mode of vitamin K prophylaxis administration
Authors: Khambalia Amina Z , Roberts Christine L , Bowen Jennifer R , Nassar Natasha
Published: April 2012

Aim:  The aim of this study was to compare maternal and infant characteristics by mode of VK administration.

Methods:  De‐identified computerised birth files of all babies born in New South Wales (NSW), Australia between January 2007 and December 2009 (when VK prophylaxis was measured) were included in the present study. The outcome variable, mode of VK prophylaxis, was recorded by checkbox as oral, IM injection, none or not stated.

Results:  We analysed population‐based birth data from 2007 to 2009 in NSW, Australia and found that IM injection was the most prevalent mode of administration (96.3%, n = 263, 555), followed by oral (2.6%, n = 7023) and none (1.2%, n = 3136). Compared to neonates receiving IM VK, those with oral or none were more likely to have vaginal births without medical interventions at birth centres or planned home births and were less likely to receive hepatitis B vaccination. Among neonates administered oral VK, a larger proportion were preterm births and breastfed at discharge compared to neonates administered VK as an IM injection. Neonates with no VK recorded were more likely to be admitted to neonatal intensive care, but may have received VK later in the birth admission.

Conclusions:  A small proportion of the Australian neonates may be at risk of inadequate protection from VKBD due to parental concerns about the safety of IM injection of VK to neonates.
Clinicopathological features of fatal cardiomyopathy in childhood: An autopsy series
Authors: Roberts Sebastian EA , Pryce Jeremy W , Weber Martin A , Malone Marian , Ashworth Michael T , Sebire Neil J
Published: April 2012

Aim:  Cardiomyopathy, a group of primary myocardial disorders, is an uncommon, but important, cause of death in childhood. This study examines the demographic, clinical and pathological features of fatal cardiomyopathy in childhood with particular reference to its classification and autopsy findings.

Method:  The method of this study was a retrospective structured review of all paediatric autopsies performed at a single specialist centre from 1995 to 2009 inclusive, in order to determine the demographic, clinical and pathological features of fatal cardiomyopathy.

Results:  From a total of 2229 autopsies performed at the centre during the study period on live‐born infants and children, 34 confirmed cases of cardiomyopathy were identified (1.5%). More than half (59%) of these cases occurred in infants (less than 1 year of age). Heart weight of cardiomyopathy cases was significantly greater than those with normal hearts (P < 0.001), and 77% had heart weights above the 95th percentile of the normal expected range for age, including all of those over 1 year age. Of cardiomyopathy cases, 50% were primary dilated cardiomyopathy and 27% were primary hypertrophic cardiomyopathy. Twelve of 34 cases (35%) presented as sudden unexpected death, the diagnosis of cardiomyopathy being only made at autopsy.

Conclusion:  Cardiomyopathy is an uncommon cause of death in infancy and childhood. It can present as sudden unexpected death and encompasses a range of aetiologies. Heart weight above the 95th percentile at autopsy is present in most cases but heart weight may be within the normal range in infants.
A clinical audit of antithrombin concentrate use in a tertiary paediatric centre
Authors: Kozul Christina , Newall Fiona , Monagle Paul , Mertyn Eliza , Ignjatovic Vera
Published: April 2012

Aim:  The aim of this study was to investigate the clinical use of antithrombin concentrate (ATC) in children and specifically to determine the current practice of ATC administration, including dosing and indications for administration.

Methods:  A clinical audit was performed of patients treated with ATC during two 12‐month periods: 1 June 1999–1 June 2000 and 1 June 2009–1 June 2010.

Results:  Thirty‐seven patients whose age ranged from 1 day to 13.5 years (median 30 days) received a median of two doses (range 1–15) with a median dose of 40 units/kg (range 1–200 units). The majority (90%) of patients were located in the intensive care unit, and the major indication (76%) for use of the ATC was in the setting of unfractionated heparin (UFH) resistance. Post‐ATC administration, 32% of the doses given resulted in antithrombin levels reaching age‐specific normative levels. Of the patients administered ATC with the aim of optimising UFH therapy, 28% of patients had their UFH dose reduced without any measurement of UFH effect.

Conclusions:  This data provides the basis for future investigations of the specific biochemical changes accompanying ATC administration and the development of paediatric‐specific evidence‐based guidelines for ATC use.
Survival analysis of pediatric dialysis patients in Taiwan
Authors: LIN HSIN‐HUNG , TSAI CHING‐WEI , LIN PAO‐HSUAN , CHENG KUANG‐FU , WU HONG‐DAR , WANG I‐KWAN , LIN CHING‐YUANG , CHEN WALTER , HUANG CHIU‐CHING
Published: April 2012

Aim:  The long‐term survival of Taiwanese children with end‐stage renal disease (ESRD) has not been reported before. This study aimed to determine the long‐term survival, mortality hazards and causes of death in paediatric patients receiving dialysis.

Methods:  Paediatric patients (aged 19 years and younger) with incident ESRD who were reported to the Taiwan Renal Registry from 1995 to 2004 were included. A total of 319 haemodialysis (HD) and 156 peritoneal dialysis (PD) patients formed the database. After stratification by dialysis modality, multivariate Cox proportional‐hazards model was constructed with age, sex and co‐morbidity as predictive variables.

Results:  The annual paediatric ESRD incidence rate was 8.12 per million of age‐related populations. The overall 1‐, 5‐, and 10‐year survival rates for PD patients were 98.1%, 88.0% and 68.4%, respectively, and were 96.9%, 87.3% and 78.5% for HD patients. The survival analysis showed no significant difference between HD and PD (P = 0.4878). Using ‘15–19 years’ as a reference group, the relative risk (RR) of the youngest group (0–4 years) was 6.60 (95% CI: 2.50–17.38) for HD, and 5.03 (95% CI: 1.23–20.67) for PD. The death rate was 24.66 per 1000 dialysis patient‐years. The three major causes of death were infection (23.4%), cardiovascular disease (13.0%) and cerebrovascular disease (10.4%). Hemorrhagic stroke (87.5%) was the main type of foetal cerebrovascular accident.

Conclusion:  We conclude that there was no significant difference of paediatric ESRD patient survival between HD and PD treatment in Taiwan. The older paediatric ESRD patients had better survival than younger patients.
Apoptotic cells in peripheral blood and multiple organ injury
Authors: Emura Iwao , Usuda Hiroyuki
Published: April 2012

To evaluate the roles of apoptotic cells in peripheral blood (PB) on multiple organ injury, five patients with hematopoietic stem cell transplantation (HSCT) and one with refractory anemia were examined. The following findings were confirmed. 1) High‐dose alkylating agents were administrated as conditioning regimens to all HSCT patients. 2) Many organs were injured in all cases. 3) Neutrophils accumulated in the capillaries of injured organs, and endothelial cells were extensively injured. 4) Large numbers of apoptotic cells and γH2AX+ cells were observed in the foci of large cells with hyperchromatic nuclei. 5) Increased numbers of apoptotic cells (6/6), γH2AX+ cells (6/6), scavenger receptor A positive (SRA+) cells (6/6), and tumor necrosis factor (TNF)‐α+ cells (5/6) were observed in PB smear preparations. 6) Cytokines exceeded the normal levels in most patients. From these findings, apoptotic cells were considered to be produced by the administration of high‐dose alkylating agents in HSCT patients, and apoptotic cells and SRA+ cells in PB were thought to play important roles in the development of multiple organ injury in HSCT and MDS patients.
Retroperitoneal schwannoma is characterized by a high incidence of cellular type and GFAP‐immunoreactivity
Authors: Hirose Takanori , Ishizawa Keisuke , Sakaki Mika , Fujii Yoshiyuki
Published: April 2012

To clarify the clinicopathologic characteristics of retroperitoneal schwannomas, which are sometimes confused with other spindle cell tumors, 27 cases were studied microscopically and immunohistochemically. The 27 cases consisted of 17 females and 10 males, the ages of whom ranged from 31–79 (mean 57.4) years. Gross examination revealed well‐demarcated, encapsulated tumors, 3–15 cm (mean 8 cm) in diameter. Microscopic review divided them into 13 cases of cellular/fascicular, 3 of conventional, 6 of intermediate, and 5 of ancient type. Cellular/fascicular schwannomas were composed of cellular fascicles of spindle cells, in which nuclear palisading, Antoni B area and cyst were unclear, while numerous foamy cells were intermingled. Immunohistochemical investigation revealed diffuse, strong positivity for S‐100 protein and Sox10 in all tumors studied. In addition, glial fibrillary acidic protein (GFAP) was extensively expressed in 92% of the cellular/fascicular type, while it was less prominent in others. The present study suggests that retroperitoneal schwannoma often occurs in the middle‐aged woman, grows to a large size, exhibits cellular/fascicular microscopic features in half of the cases, and may arise from GFAP‐positive Schwann cells. The presence of hyalinized vessels and dense infiltration of foamy macrophages as well as diffuse immunoreactivity for S‐100 protein and Sox10 are helpful for the differential diagnosis.
Pre‐ and postnatal exposure to kynurenine causes cognitive deficits in adulthood
Authors: Pocivavsek Ana , Wu Hui‐Qiu , Elmer Greg I. , Bruno John P. , Schwarcz Robert
Published: April 2012

Levels of kynurenic acid (KYNA), an endogenous product of tryptophan degradation, are elevated in the brain and cerebrospinal fluid of individuals with schizophrenia (SZ). This increase has been implicated in the cognitive dysfunctions seen in the disease, as KYNA is an antagonist of the α7 nicotinic acetylcholine receptor and the N‐methyl‐d‐aspartate receptor, both of which are critically involved in cognitive processes and in a defining neurodevelopmental period in the pathophysiology of SZ. We tested the hypothesis that early developmental increases in brain KYNA synthesis might cause biochemical and functional impairments in adulthood. To this end, we stimulated KYNA formation by adding the KYNA precursor kynurenine (100 mg/day) to the chow fed to rat dams from gestational day 15 to postnatal day 21 (PD 21). This treatment raised brain KYNA levels in the offspring by 341% on PD 2 and 210% on PD 21. Rats were then fed normal chow until adulthood (PD 56–80). In the adult animals, basal levels of extracellular KYNA, measured in the hippocampus by in vivo microdialysis, were elevated (+12%), whereas extracellular glutamate levels were significantly reduced (−13%). In separate adult animals, early kynurenine treatment was shown to impair performance in two behavioral tasks linked to hippocampal function, the passive avoidance test and the Morris water maze test. Collectively, these studies introduce a novel, naturalistic rat model of SZ, and also suggest that increases in brain KYNA during a vulnerable period in brain development may play a significant role in the pathophysiology of the disease.
γ‐Aminobutyric acid receptor A‐mediated inhibition in the honeybee’s antennal lobe is necessary for the formation of configural olfactory percepts
Authors: Choudhary Amir F. , Laycock Ian , Wright Geraldine A.
Published: April 2012

Complex odours often possess perceptual qualities that are distinct from their components. Previous studies in humans, rodents, and insects indicate that the perception of complex odour blends depends on the concentration of the components and the mixture’s complexity. However, we know relatively little about the way that an odour mixture ‘gestalt’ is produced by the olfactory system. Here, using an assay for olfactory conditioning in the honeybee (Apis mellifera), we examine the role of γ‐aminobutyric acid receptor A (GABAA)‐ergic inhibition within the olfactory primary relay, the antennal lobe, in the formation of a unique odour percept for complex odours. We found that honeybees perceive odour mixtures as configural stimuli when the mixtures were of low concentration and when they were composed of more than two odorants. When GABAA receptors were disrupted using the antagonist, picrotoxin, injected directly into the antennal lobe, we observed that bees no longer perceived the mixture as a configural stimulus. Our results imply that synchronization of antennal lobe projection neurons mediated by GABAA receptors is the mechanism responsible for the formation of unique olfactory percepts for complex odours.
Predicting present and future intra‐specific genetic structure through niche hindcasting across 24 millennia
Authors: Espíndola Anahí , Pellissier Loïc , Maiorano Luigi , Hordijk Wim , Guisan Antoine , Alvarez Nadir
Published: April 2012

Ecology Letters (2012) 15: 649–657

Paleoclimatic reconstructions coupled with species distribution models and identification of extant spatial genetic structure have the potential to provide insights into the demographic events that shape the distribution of intra‐specific genetic variation across time. Using the globeflower Trollius europaeus as a case‐study, we combined (1) Amplified Fragment Length Polymorphisms, (2) suites of 1000‐years stepwise hindcasted species distributions and (3) a model of diffusion through time over the last 24,000 years, to trace the spatial dynamics that most likely fits the species’ current genetic structure. We show that the globeflower comprises four gene pools in Europe which, from the dry period preceding the Last Glacial Maximum, dispersed while tracking the conditions fitting its climatic niche. Among these four gene pools, two are predicted to experience drastic range retraction in the near future. Our interdisciplinary approach, applicable to virtually any taxon, is an advance in inferring how climate change impacts species’ genetic structures.
Cultivation of a highly enriched ammonia‐oxidizing archaeon of thaumarchaeotal group I.1b from an agricultural soil
Authors: Kim Jong‐Geol , Jung Man‐Young , Park Soo‐Je , Rijpstra W. Irene C. , Sinninghe Damsté Jaap S. , Madsen Eugene L. , Min Deullae , Kim Jin‐Seog , Kim Geun‐Joong , Rhee Sung‐Keun
Published: April 2012

Nitrification of excess ammonia in soil causes eutrophication of water resources and emission of atmospheric N2O gas. The first step of nitrification, ammonia oxidation, is mediated by Archaea as well as Bacteria. The physiological reactions mediated by ammonia‐oxidizing archaea (AOA) and their contribution to soil nitrification are still unclear. Results of non‐culture‐based studies have shown the thaumarchaeotal group I.1b lineage of AOA to be dominant over both AOA of group I.1a and ammonia‐oxidizing bacteria in various soils. We obtained from an agricultural soil a highly enriched ammonia‐oxidizing culture dominated by a single archaeal population [c. 90% of total cells, as determined microscopically (by fluorescence in situ hybridization) and by quantitative PCR of its 16S rRNA gene]. The archaeon (termed ‘strain JG1’) fell within thaumarchaeotal group I.1b and was related to the moderately thermophilic archaeon, Candidatus Nitrososphaera gargensis, and the mesophilic archaeon, Ca. Nitrososphaera viennensis with 97.0% and 99.1% 16S rRNA gene sequence similarity respectively. Strain JG1 was neutrophilic (growth range pH 6.0–8.0) and mesophilic (growth range temperature 25–40°C). The optimum temperature of strain JG1 (35–40°C) is > 10°C higher than that of ammonia‐oxidizing bacteria (AOB). Membrane analysis showed that strain JG1 contained a glycerol dialkyl glycerol tetraether, GDGT‐4, and its regioisomer as major core lipids; this crenarchaeol regioisomer was previously detected in similar abundance in the thermophile, Ca. N. gargensis and has been frequently observed in tropical soils. Substrate uptake assays showed that the affinity of strain JG1 for ammonia and oxygen was much higher than those of AOB. These traits may give a competitive advantage to AOA related to strain JG1 in oligotrophic environments. 13C‐bicarbonate incorporation into archaeal lipids of strain JG1 established its ability to grow autotrophically. Strain JG1 produced a significant amount of N2O gas – implicating AOA as a possible source of N2O emission from soils. Sequences of archaeal amoA and 16S rRNA genes closely related to those of strain JG1 have been retrieved from various terrestrial environments in which lineage of strain JG1 is likely engaged in autotrophic nitrification.
Linking selenium biogeochemistry to the sulfur‐dependent biological detoxification of arsenic
Authors: Couture Raoul‐Marie , Sekowska Agnieszka , Fang Gang , Danchin Antoine
Published: April 2012

Geochemistry often reveals unexpected (anti)correlations. Arsenic (As) and selenium (Se) are cases in point. We explore the hypothesis that bacteria living in an As‐replete environment recruited a biological process involving Se and sulfur to fulfil their need for As detoxification. In analogy with the formation of arsenolipids and arsenosugars, which are common non‐toxic As metabolites derived from microbial and plant metabolism, we attempt to explain the prevalence of novel sulfur‐containing As derivatives, in particular monothioarsenate, in the aqueous environment. Thiolated‐As species have been overlooked so far mainly because of the difficulty of their identification. Based on comparative genomics, we propose a scenario where SelD and SelU proteins, commonly used to make selenophosphate and modify transfer RNA, have been recruited to make monothioarsenate, a relatively innocuous arsenical. This hypothesis is discussed in terms of the relative geochemical distribution of Se and As.
Factors influencing initial choice of insulin therapy in a large international non‐interventional study of people with type 2 diabetes
Authors: Freemantle N. , Balkau B. , Danchin N. , Wang E. , Marre M. , Vespasiani G. , Kawamori R. , Home P. D.
Published: April 2012

Aim: To use baseline characteristics of the Cardiovascular Risk Evaluation in people with type 2 Diabetes on Insulin Therapy study population to identify factors that could explain the choice of insulin therapy when beginning insulin.

Methods: The source, non‐interventional, longitudinal, long‐term study involves 314 centres in 12 countries in five regions. People were enrolled having started any insulin regimen in the previous 12 months. To identify factors associated with the choice of insulin regimen, multivariable backward logistic regression was performed on eligible physician and participant explanatory variables.

Results: Participants (N = 3031) had mean age 62 years, diabetes duration 11 years, body mass index 29.3 kg/m2 and an HbA1c of 9.5%. Participants in Japan had less hypertension, smoked more and used fewer concomitant medications than those of other regions. Only physician location (rural or urban) influenced the choice of insulin in Japan. In the other four‐regions‐combined, physician location, specialty, sex and practice type influenced choice of insulin as did participant location, baseline HbA1c, use of glucose‐lowering therapies and prior insulin secretagogue use.

Conclusion: Choice of initial insulin regimen was influenced by several physician and participant characteristics in Canada and Europe, but only by physician location in Japan.
CARBON GEOGRAPHY: THE POLITICAL ECONOMY OF CONGRESSIONAL SUPPORT FOR LEGISLATION INTENDED TO MITIGATE GREENHOUSE GAS PRODUCTION
Authors: CRAGG MICHAEL I. , ZHOU YUYU , GURNEY KEVIN , KAHN MATTHEW E.
Published: April 2012

Over the last 5 years, the U.S. Congress has voted on several pieces of legislation intended to sharply reduce the nation's greenhouse gas emissions. Given that climate change is a world public bad, standard economic logic would predict that the United States would “free ride” and wait for other nations to reduce their emissions. Within the Congress, there are clear patterns to who votes in favor of mitigating greenhouse gas emissions. This paper presents a political economy analysis of the determinants of “pro‐green” votes on such legislation. Conservatives consistently vote against such legislation. Controlling for a representative's ideology, representatives from richer districts and districts with a lower per‐capita carbon dioxide footprint are more likely to vote in favor of climate change mitigation legislation. Representatives from districts where industrial emissions represent a larger share of greenhouse gas emissions are more likely to vote no. (JEL Q54, Q58, R50)
A constructionism framework for designing game‐like learning systems: Its effect on different learners
Authors: Li Zhong‐Zheng , Cheng Yuan‐Bang , Liu Chen‐Chung
Published: April 2012

Game‐like learning systems such as simulation games and digital toys are increasingly being applied to foster higher‐level abilities in educational contexts, as they may facilitate an active learning experience. However, the effect of such game‐like learning systems is not guaranteed because students may only be interested in the fantasy interfaces and the elaborate scenarios, rather than in the learning tasks. In this vein, the study presented in this paper addresses this issue from the perspective of constructionism. A design framework based on constructionism, which highlights the principles of construction as the goal, low‐threshold–high‐ceiling and computer simulation is proposed for designing game‐like learning systems. An evaluation was conducted to investigate the influence of the framework on the flow experiences and learning strategies of different students. The results of this study show that computer simulation is an integral component to promote exploratory learning activities. The results of this study also indicate that the framework was particularly helpful for those students with low background knowledge in balancing challenge and skill perceptions. For those students with middle and high level background knowledge, it also promoted the learning experience by either reducing the challenge perception or promoting the skill perception. Such findings suggest that the constructionism framework is a particularly important design guideline to engage students of different levels in active learning activities.

Practitioner Notes

What is already known about this topic

Computer games are increasingly being applied to foster higher‐level abilities in educational contexts.

Learning with a game is sensitive to individual differences.

What this paper adds

A game design framework based on constructionism is proposed to illustrate how low‐threshold–high‐ceiling principle and computer simulations may be used to help students of different levels learn with games.

Implications for practice and/or policy

Computer simulation is an integral component to promote exploratory learning activities.

The constructionism framework was mostly helpful for those students with low background knowledge in balancing challenge and skill perceptions.

The low‐threshold–high‐ceiling principle is a particularly important design guideline to engage students of different levels in active learning activities.
Discriminating factors between completers of and dropouts from online learning courses
Authors: Lee Youngju , Choi Jaeho , Kim Taehyun
Published: April 2012

This study examined the differences between persistent and dropout students enrolled in an online course with five factors: support from family and work, academic locus of control, academic self‐efficacy, time and environment management skills, and metacognitive self‐regulation skills. Moreover, this study investigated the most significant factors discriminating students' success in their online course completion. A total of 169 adult students participated in the study. We used online surveys, which consisted of 27 items adopted from the literature, to measure the level of five factors of which students perceive. The analysis showed persistent students had higher levels of academic locus of control and metacognitive self‐regulation skills than dropout students. Our finding suggests that these factors are the most significant factors influencing students' persistence in an online course.

Practitioner Notes

What is already known about this topic

Student dropout rates in online learning are much higher than ones in conventional learning environment.

To explain or predict dropout in online courses, several conceptual models were suggested: Tinto's (1975) Student Integration Model, Bean and Metzner's (1985) Student Attrition Mode and Rovai's (2003) Composite Persistence Model.

Research found several significant predictors of dropout: locus of control, metacognitive strategies, self‐efficacy, resource management skills, and support from family and work.

What this paper adds

This study suggested an integrated approach to assess the effects of multiple predictors simultaneously using multivariate analysis of variance.

Results of this study revealed the relative powers of these factors to predict dropout.

In addition, this study provided empirical results for Rovai's conceptual model, supporting the original design partly.

Implications for practice and/or policy

Students' entry characteristics including academic locus of control and metacognitive strategies need to be assessed in the beginning of a semester to better address students' weakness during the course.

Depending on students' preparedness for online courses, teachers and administrators could provide necessary support, such as technical supports, interactive learning activities and student‐centered web design.

Interactive web design and learning activities could improve self‐regulated learning skills of online students.
Mounce and Winch on Understanding (or Not Understanding) an Indigenous Society
Authors: Burley Mikel
Published: April 2012

Howard Mounce and Peter Winch both made novel and illuminating contributions to discussions about how, or whether, we can understand societies very different from our own – societies that would, these days, be referred to as “indigenous,”“tribal,”“traditional” or “small‐scale.” This paper aims to elucidate some disagreements between Mounce and Winch while also critically engaging in the debate. The concepts of “practice” and “language‐game” are considered in connection with magic‐related activities among the Azande of north‐central Africa, and Mounce's contention that the Azande's whole way of speaking about magic and witchcraft is “hardly intelligible” is examined. I challenge Mounce's interpretations of certain analogies that he uses, and propose that his argument relies on what is probably an underestimation of the degree to which magic and witchcraft are integral to Azande culture as a whole.
Exchange Rates and Long‐Term Bonds*
Authors: Alexius Annika , Sellin Peter
Published: April 2012

There is tentative evidence to suggest that the well‐documented empirical failure of uncovered interest parity (UIP) is confined to short‐term interest rates. However, tests of UIP for long‐term bonds are thwarted by various data problems. These data problems can be avoided by focusing on short investments in long‐term bonds. This paper concerns the relationship between changes in the US dollar–Deutsche Mark exchange rate and returns to short investments in US and German long‐term government bonds. The hypothesis that expected returns to investments in bonds denominated in the two currencies are equal is not rejected, and the estimated slope coefficients are positive. For corresponding short‐term interest rates, the typical finding of negative and large Fama coefficients is confirmed. We conclude that it is the maturity of the asset, rather than the investment horizon, that matters for the results.
Parametric Inference in Stationary Time Series Models with Dependent Errors
Authors: SHAO XIAOFENG
Published: April 2012

This article is concerned with inference for the parameter vector in stationary time series models based on the frequency domain maximum likelihood estimator. The traditional method consistently estimates the asymptotic covariance matrix of the parameter estimator and usually assumes the independence of the innovation process. For dependent innovations, the asymptotic covariance matrix of the estimator depends on the fourth‐order cumulants of the unobserved innovation process, a consistent estimation of which is a difficult task. In this article, we propose a novel self‐normalization‐based approach to constructing a confidence region for the parameter vector in such models. The proposed procedure involves no smoothing parameter, and is widely applicable to a large class of long/short memory time series models with weakly dependent innovations. In simulation studies, we demonstrate favourable finite sample performance of our method in comparison with the traditional method and a residual block bootstrap approach.
Organisation‐level policy towards older workers in Poland
Authors: Perek‐Białas Jolanta , Turek Konrad
Published: April 2012

Perek‐Białas J, Turek K. Organisation‐level policy towards older workers in Poland

This article presents the results of studies on organisation‐level strategies towards older workers in Poland. The analyses were based on a national and representative sample survey of 1,037 companies (public and private sectors) – the first of its kind in Poland. The question of the survey was: How do Polish employers deal with an ageing workforce and how can management tap into their potential through various measures? The analyses revealed three different strategies: (i) improvement of productivity – trying to improve the skills and competencies of older workers, increase their effective use of and adjustment to the workplace, plan individual career moves and avoid work burn‐out; (ii) the pushing out of older workers – attempting to rid the workplace of older workers as quickly as possible; (iii) accommodation and reduction of labour costs – slowly preparing senior workers for retirement and creating conditions that would meet their actual needs.
Early menopause and risk of osteoporosis, fracture and mortality: a 34‐year prospective observational study in 390 women
Authors: Svejme O , Ahlborg HG , Nilsson J‐Å , Karlsson MK
Published: April 2012

Please cite this paper as: Svejme O, Ahlborg H, Nilsson J, Karlsson M. Early menopause and risk of osteoporosis, fracture and mortality: a 34‐year prospective observational study in 390 women. BJOG 2012;119:810–816.

Objective  A prospective evaluation of the long‐term effects of early menopause on mortality, risk of fragility fracture and osteoporosis.

Design  Prospective population‐based observational study.

Setting  Malmö, Sweden.

Population  A total of 390 white north European women aged 48 years at the start of the study.

Methods  At baseline, bone mineral density (BMD) was measured by single‐photon absorptiometry (SPA) in the distal forearm and menopausal status was noted. Menopause was determined according to the World Health Organization criterion of a minimum of 12 months of continuous amenorrhoea. Women were divided into early menopause (occurring before age 47 years) and late menopause (occurring at age 47 years or later). At age 77, forearm BMD was re‐measured by SPA and proximal femur and lumbar spine BMD were measured by dual‐energy X‐ray absorptiometry (DXA). The prevalence of osteoporosis was determined using the DXA data. Mortality rate and the incidence of fractures were registered up until age 82. Data are presented as means with 95% confidence intervals (95% CI).

Main outcome measures  Incidence of fragility fractures, mortality, prevalence of osteoporosis at age 77.

Results  Women with early menopause had a risk ratio of 1.83 (95% CI 1.22–2.74) for osteoporosis at age 77, a risk ratio of 1.68 (95% CI 1.05–2.57) for fragility fracture and a mortality risk of 1.59 (95% CI 1.04–2.36).

Conclusions  Menopause before age 47 is associated with increased mortality risk and increased risk of sustaining fragility fractures and of osteoporosis at age 77.
Effect of tillage and crop on arbuscular mycorrhiza colonization of winter wheat and triticale under Mediterranean conditions
Authors: Brito I. , Goss M. J. , De Carvalho M.
Published: April 2012

Large‐scale inoculation with arbuscular mycorrhizal fungi (AMF) is generally impractical in most regions and we have little understanding of the factors that determine inoculation success. Nevertheless, the ability to take full advantage of indigenous AMF for sustainable production needs to be developed within cropping systems. We used part of a long‐term field experiment to understand the influence of tillage and the preceding crop on AMF colonization over the growing season. Arbuscular mycorrhiza colonization rate was more affected by treatment (tillage or the combination of crop and preceding crop) than by the total number of AMF spores in the soil. Conventional tillage (CT) had a statistically significant negative effect (P ≤ 0.05) on spore numbers isolated from the soil, but only in the first year of study. However, the AMF colonization rate was significantly reduced by CT, and the roots of wheat, Triticum aestivum, L, cv. Coa after sunflower, Helianthus annuus L., were less well colonized than were those of triticale, X Triticosecale Wittmack, cv. Alter after wheat, but the affect of tillage was more pronounced than was the effect of crop combination. Under no‐till there was a significant increase in AMF colonization rate throughout the sampling period in both wheat and triticale, indicating that the extraradical mycelium previously produced acted as a source of inoculum. In general, triticale showed greater AMF colonization than wheat, despite the preceding crop being less mycotrophic. Under these experimental conditions, typical of Mediterranean agricultural systems, AMF colonization responded more strongly to tillage practices than to the combination of crop and preceding crop.
Science, scientific instruments and questions of method in nineteenth‐century British geography
Authors: Withers Charles W J
Published: April 2012

The paper explores the promotion of method in nineteenth‐century British geography. Attention is paid to the emphasis accorded scientific instruments in a period when scientific subjects were, in practice and in personnel, ‘disciplining’ themselves. The role ascribed to scientific instruments and method is examined with reference to the work in the Royal Geographical Society of Julian R. Jackson and hisWhat to observe, or the traveller’s remembrancer(1841), and William Hamilton’s essay on geographical methods in John Herschel’sManual of scientific enquiry(1849). These works are further explored with reference to two related texts, the Society’sHints to travellers(Raper and Fitzroy 1854) and Francis Galton’sThe art of travel(1855). The paper for the first time brings together evidence for the place of scientific instruments within geography’s methodological pronouncements with scholarship in the history of technology and the history of science. In doing so, the paper highlights the importance of critical histories of geography’s methods, instruments and associated practices. The conclusion addresses the implications of such research for providing yet richer histories of geography that might address not just the subject’s cognitive content and institutional context but matters of epistemological procedure, moral conduct and authorial regimen in relation to precision instrumentation.
Characterization of DDRI‐18 (3,3′‐(1H,3′H‐5,5′‐bibenzo[d]imidazole‐2,2′‐diyl)dianiline), a novel small molecule inhibitor modulating the DNA damage response
Authors: Jun DW , Jeong YS , Kim HJ , Jeong K‐C , Kim S , Lee C‐H
Published: April 2012

BACKGROUND AND PURPOSE

Recently, the DNA damage response (DDR) has emerged as a promising target for anticancer drug development. In our previous study, we identified several DDR‐inhibiting compounds via high‐content screening of a small molecule library using γH2AX foci as a biomarker. Here, we studied the effects of the DNA damage response inhibitor DDRI‐18 (3,3′‐(1H,3′H‐5,5′‐bibenzo[d]imidazole‐2,2′‐diyl)dianiline) on DDR.

EXPERIMENTAL APPROACH

Osteosarcoma U2OS cells were treated with etoposide to induce DDR. The nuclear foci of γH2AX and other signalling molecules in DDR were visualized by immunofluorescence and quantified using an IN Cell Analyzer. The DNA repair capacity of cells was analysed using the comet assay and in vivo DNA end‐joining assay. Cell survival after drug treatment was quantified using the MTT assay, and apoptotic cell death was analysed by Annexin V staining and flow cytometry.

KEY RESULTS

DDRI‐18 inhibited the non‐homologous end‐joining (NHEJ) DNA repair process and delayed the resolution of DNA damage‐related proteins (γH2AX, ATM and BRCA1) from DNA lesions at a later phase of DDR. Furthermore, DDRI‐18 enhanced the cytotoxic effects of anticancer DNA‐damaging drugs, including etoposide, camptothecin, doxorubicin and bleomycin. This synergistic effect on cell death was shown to be due to caspase‐dependent apoptosis.

CONCLUSIONS AND IMPLICATIONS

We identified a chemical compound, DDRI‐18, that has chemosensitization activity. Although the target molecule and mechanism of action of DDRI‐18 remain unknown, DDRI‐18 is an effective chemosensitizing agent and may improve the therapy with classical anticancer drugs.
Ostracod palaeoecology and environmental change in the Laptev and Kara seas (Siberian Arctic) during the last 18 000 years
Authors: Stepanova Anna , Taldenkova Ekaterina , Bauch Henning A.
Published: April 2012

Fossil ostracod assemblages were investigated in five AMS 14
C‐dated cores from various water depths of the Laptev and Kara seas ranging from the upper continental slope (270 m) to the present‐day shelf depth (40 m). Six fossil assemblages were distinguished. These represent the varying environmental conditions at the North Siberian continental margin since about 18 ka. In the cores from the shelf the ostracod assemblages reflect the gradual transition from an estuarine brackish‐water environment to modern marine conditions since 12.3 ka, as induced by the regional early Holocene transgression. The core from the upper continental slope dates back to c. 17.6 ka and contains assemblages that are absent in the shelf cores. The assemblage older than 10 ka stands out as a specific community dominated by relatively deep‐water Arctic and North Atlantic species that also contains euryhaline species. Such an assemblage provides evidence for past inflows of Atlantic‐derived waters from as early as c. 17.2 ka, probably facilitated by upwelling in coastal polynyas, and a considerable riverine freshwater influence with enhanced surface water stratification owing to the proximity of the palaeocoastline until early Holocene times. In all studied cores, relative increases in euryhaline species dominant in the inner‐shelf regions are recorded in the mid–late Holocene sediments (<7 ka), which otherwise already contain modern‐like ostracod assemblages with relatively deep‐water species. This observation suggests euryhaline species to be largely sea‐ice‐ and/or iceberg‐rafted and therefore may provide evidence for a climate cooling trend.
An Incompletely Penetrant Novel Mutation in COL7A1 Causes Epidermolysis Bullosa Pruriginosa and Dominant Dystrophic Epidermolysis Bullosa Phenotypes in an Extended Kindred
Authors: Yang Catherine S. , Lu Yin , Farhi Anita , Nelson‐Williams Carol , Kashgarian Michael , Glusac Earl J. , Lifton Richard P. , Antaya Richard J. , Choate Keith A.
Published: April 2012

Abstract:  Epidermolysis bullosa pruriginosa (EBP) is a rare subtype of dystrophic epidermolysis bullosa (DEB) characterized by intense pruritus, nodular or lichenoid lesions, and violaceous linear scarring, most prominently on the extensor extremities. Remarkably, identical mutations in COL7A1, which encodes an anchoring fibril protein present at the dermal–epidermal junction, can cause both DEB and EBP with either autosomal dominant or recessive inheritance. We present one family with both dystrophic and pruriginosa phenotypes of epidermolysis bullosa. The proband is a 19‐year‐old Caucasian woman who initially presented in childhood with lichenoid papules affecting her extensor limbs and intense pruritus consistent with EBP. Her maternal grandmother saw a dermatologist for similar skin lesions that developed without any known triggers at age 47 and mostly resolved spontaneously after approximately 10 years. The proband’s younger brother developed a small crop of pruritic papules on his elbows, dorsal hands, knees, and ankles at age 13. Her second cousin once removed, however, reported a mild blistering disease without pruritus consistent with DEB. Genetic sequencing of the kindred revealed a single dominant novel intron 47 splice site donor G>A mutation, c.4668 + 1 G>A, which we predict leads to exon skipping. Incomplete penetrance is confirmed in her clinically unaffected mother, who carries the same dominant mutation. The wide diversity of clinical phenotypes with one underlying genotype demonstrates that COL7A1 mutations are incompletely penetrant and strongly suggests that other genetic and environmental factors influence clinical presentation.