bluuebunny/crossref_metadata_2025 huggingface dataset:
Modelling wildfire activity in Iberia with different atmospheric circulation weather types
Authors: Trigo Ricardo M. , Sousa Pedro M. , Pereira Mário G. , Rasilla Domingo , Gouveia Célia M.
Published: June 2013

This work focuses on the spatial and temporal variability of burnt area (BA) in the entire Iberian Peninsula (IP) and on the construction of statistical models to reproduce the inter‐annual variability. A novel common dataset was assembled for the whole IP by merging the registered BA from 66 administrative regions of both Portugal and Spain. We applied a cluster analysis to identify larger regions with similar fire regimes and results point to the existence of four clusters (Northwestern, Northern, Southwestern and Eastern) whose spatial patterns and seasonal fire regimes are shown to be related with constraining factors such as topography, vegetation cover and climate conditions. The relationship between BA at monthly time scale with both long‐term climatic pre‐conditions and short‐term synoptic forcing was assessed using correlation and regression analysis based on: (1) temperature and precipitation from 2 to 7 months in advance to fire peak season, (2) synoptic weather patterns derived from 11 distinct Weather Types Classifications (WTC). Different relations were obtained for each IP region with a relevant link being identified between BA and short‐term synoptic forcing for all clusters, while the relation with long‐term climatic preconditioning was relevant for all but one cluster. Stepwise regression models based on the best climatic and synoptic circulation predictors were developed with cross‐validation to avoid over fitting. The performance of the models varies within IP regions, though models exclusively based on WTC tend to better reproduce the annual BA time series than those merely based on pre‐conditioning climatic information. Nevertheless, the use of both synoptic and climatic predictors provides the best results, particularly for the two western clusters, with Pearson correlation coefficient values higher than 0.7. Finally, it is shown that typical synoptic configurations that favour high values of BA correspond to dry and warm wind flows associated with anti‐cyclonic regimes.
Reconstructing Quaternary Rhine–Meuse dynamics in the southern North Sea: architecture, seismo‐lithofacies associations and malacological biozonation
Authors: RIJSDIJK K. F. , KROON I. C. , MEIJER T. , PASSCHIER S. , VAN DIJK T. A. G. P. , BUNNIK F. P. M. , JANSE A. C.
Published: June 2013

Mapping the Middle to Upper Pleistocene Rhine–Meuse sequence in the southern North Sea based on new core and seismic data has allowed a detailed palaeoenvironmental re‐assessment. An integrated seismo‐lithostratigraphic and malacological biostratigraphic framework is correlated with the optically stimulated luminescence‐dated Rhine–Meuse sequence onshore. The data point to a dynamic interplay of fluvial and marine systems in the southern part of the North Sea driven by longer‐term (>100 ka) tectonic and epeirogenic processes and shorter‐term (<10 ka) climatic processes. The final permanent breaching of the Cretaceous chalk at the Strait of Dover during the Saalian (Marine Isotope Stage 6, MIS 6) ice age led to the formation of the ‘Eurogeul’ belt, a gravelly sand belt that represents the largest concentration of gravelly fluvial sediments in the southern North Sea. The formation and preservation of the Rhine–Meuse sequence is related to long‐term (>100 ka) uplift of the Wealden–Artois synclinorium and compaction‐driven subsidence of Tertiary shales within the Voorne Trough. The dominant erosive sedimentary signatures within the Rhine–Meuse sequence resulted through shorter‐term (<10 ka) interplay of Pleistocene transgressions, glaciations and the permanent breaching of the Cretaceous chalk at the Strait of Dover by the Palaeo‐Channel river during the Saalian (MIS 6).
Lipid characterization and properties of protein hydrolysates obtained from discarded Mediterranean fish species
Authors: García‐Moreno Pedro J , Pérez‐Gálvez Raúl , Espejo‐Carpio F Javier , Muñío María M , Guadix Antonio , Guadix Emilia M
Published: June 2013

BACKGROUND

Discards are an important fraction of the by‐products produced by the fishing industry. As a consequence of their low commercial acceptance, it is necessary to provide added value to these underutilized materials. In this study the lipid fraction of three discarded fish species in the western Mediterranean Sea, namely sardine (Sardina pilchardus), mackerel (Scomber colias) and horse mackerel (Trachurus trachurus), was characterized and the angiotensin I‐converting enzyme (ACE)‐inhibitory and antioxidative activities of their protein hydrolysates were evaluated.

RESULTS

Processing of these biomaterials led to oils with a high content of omega‐3 polyunsaturated fatty acids (PUFAs), ranging from 220.5 g kg−1 for horse mackerel to 306.0 g kg−1 for sardine. Regarding the protein fraction, most of the hydrolysates presented ACE inhibition values higher than 60%, corresponding to IC50 values varying from 345 µg protein mL−1 for mackerel to 400 µg protein mL−1 for sardine. Moreover, most of the hydrolysates exhibited acceptable antioxidative activity, namely 35–45% inhibition of 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH).

CONCLUSION

This study suggests that the three discarded species evaluated are valuable raw materials for the production of bioactive ingredients such as omega‐3 PUFAs and protein hydrolysates exhibiting antihypertensive and antioxidative activities. © 2013 Society of Chemical Industry
Analysis of a conserved cellulase transcriptional regulator reveals inducer‐independent production of cellulolytic enzymes in Neurospora crassa
Authors: Coradetti Samuel T. , Xiong Yi , Glass N. Louise
Published: June 2013

Cellulose is recalcitrant to deconstruction to glucose for use in fermentation strategies for biofuels and chemicals derived from lignocellulose. In Neurospora crassa, the transcriptional regulator, CLR‐2, is required for cellulolytic gene expression and cellulose deconstruction. To assess conservation and divergence of cellulase gene regulation between fungi from different ecological niches, we compared clr‐2 function with its ortholog (clrB) in the distantly related species, Aspergillus nidulans. Transcriptional profiles induced by exposure to crystalline cellulose were similar in both species. Approximately 50% of the cellulose‐responsive genes showed strict dependence on functional clr‐2/clrB, with a subset of 28 genes encoding plant biomass degrading enzymes that were conserved between N. crassa and A. nidulans. Importantly, misexpression of clr‐2 under noninducing conditions was sufficient to drive cellulase gene expression, secretion, and activity in N. crassa, to a level comparable to wild type exposed to Avicel. However, misexpression of clrB in A. nidulans was not sufficient to drive cellulase gene expression under noninducing conditions, although an increase in cellulase activity was observed under crystalline cellulose conditions. Manipulation of clr‐2 orthologs among filamentous fungi may enable regulated cellulosic enzyme production in a wide array of culture conditions and host strains, potentially reducing costs associated with enzyme production for plant cell wall deconstruction. However, this functionality may require additional engineering in some species.
The relationship between cerebral white matter hyperintensities and lower urinary tract function in a population based, geriatric cohort
Authors: Wehrberger Clemens , Jungwirth Susanne , Fischer Peter , Tragl Karl‐Heinz , Krampla Wolfgang , Marlies Wehrberger , Madersbacher Stephan
Published: June 2013

Introduction

White matter hyperintensities (WHM) in cerebral MRI‐scan have been suspected to be involved in the pathogenesis for geriatric LUTS. Aim of this study was to investigate this association in a geriatric cohort.

Materials and Methods

The VITA‐study is a prospective, population‐based study initiated 2000/2001. All inhabitants of a well‐defined area in Vienna aged 75 years were recruited and underwent detailed regular visits including cerebral MRI‐scans. Subcortical and periventricular WMHs were classified according to the Fazekas‐classification. In 2010, all subjects alive were contacted to complete the Bristol LUTS questionnaire.

Results

Two hundred seventeen participants (75 men, 142 women), all 85 years old, entered this analysis. Urgency, frequency, and nocturia was present in 39 (50.7%), 53 (52%), and 55 (73.3%) men and 79 (55.6%), 81 (78.2%), and 68 (47.9%) women, respectively. OAB symptoms were seen in 55% of women and 50% of men. At baseline, WMH were present in 68.2% and this percentage increased to 85.7% at the most recent follow‐up. Several symptoms were more prevalent in participants without WMH as compared to those with WMH, (urgency: 71% vs. 53%, P = 0.06, nocturia: 77% vs. 53%, P = 0.01: OAB‐symptoms: 71% vs. 51%, P = 0.05. Only frequency was more prevalent in participants with WMH (77% vs. 68%, P = 0.27). In general, sub‐categorization into periventricular and subcortical WMH confirmed these data. Furthermore the amount of WMH‐burden did not correlate to LUT dysfunction.

Conclusion

This study failed to demonstrate a clear association between several aspects of LUTS and WMH in a rather healthy, population‐based 85‐year‐old cohort. Neurourol. Urodynam. 33:431–436, 2014. © 2013 Wiley Periodicals, Inc.
A spline‐based enrichment function for arbitrary inclusions in extended finite element method with applications to finite deformations
Authors: Benowitz Brett A. , Waisman Haim
Published: June 2013

A novel enrichment function, which can model arbitrarily shaped inclusions within the framework of the extended finite element method, is proposed. The internal boundary of an arbitrary‐shaped inclusion is first discretized, and a numerical enrichment function is constructed ‘on the fly’ using spline interpolation. We consider a piecewise cubic spline which is constructed from seven localized discrete boundary points. The enrichment function is then determined by solving numerically a nonlinear equation which determines the distance from any point to the spline curve. Parametric convergence studies are carried out to show the accuracy of this approach compared with pointwise and linear segmentation of points for the construction of the enrichment function in the case of simple inclusions and arbitrarily shaped inclusions in linear elasticity. Moreover, the viability of this approach is illustrated on a neo‐Hookean hyperelastic material with a hole undergoing large deformation. In this case, the enrichment is able to adapt to the deformation and effectively capture the correct response without remeshing. Copyright © 2013 John Wiley & Sons, Ltd.
Relationship of food addiction to weight loss and attrition during obesity treatment
Authors: Lent Michelle R. , Eichen Dawn M. , Goldbacher Edie , Wadden Thomas A. , Foster Gary D.
Published: June 2013

Objective

The relationship between food addiction (FA) and weight and attrition outcomes in overweight and obese adults participating in weight loss interventions were prospectively examined in this study.

Design and Methods

Participants were 178 adults (51.2 ± 11.7 y, 36.1 ± 4.8 kg/m2) in one of two outpatient weight loss treatment programs for approximately 6 months. The Yale Food Addiction Scale (YFAS) assessed FA diagnosis and symptom count. The relationship between FA and weight loss and attrition was assessed.

Results

After controlling for treatment arm, gender, and baseline weight, there was no effect of FA status on weight loss (P = 0.17) or attrition (P = 0.37). Similarly, baseline FA symptom count was not associated with weight loss (P = 0.14) or attrition (P = 0.10).

Conclusions

Neither FA status nor symptom count affects weight loss or attrition during weight loss treatment.
Viral political communication and readability: an analysis of an Italian political blog
Authors: Bigi Alessandro
Published: June 2013

The Internet is widely used by political parties to report events and to send messages to the voting population. Politicians used digital media (websites, blogs, bulletin boards/lists, and chat/instant messaging) in recent elections, together with traditional media (television, newspapers, rallies, etc.). Political blogs represent not only an additional communication channel but also an instrument for spreading editorial content and messages, virally infecting more traditional media channels. A key task for any political party or politician is to make the blog understandable and easy to read as a first step to ignite and spread the right viral effect. To reach this goal, writers must consider both their content and their target audience. This article measures the readability of the text of a political blog to provide insight on the effectiveness of viral communication using blogs. The Beppegrillo.it blog was analyzed from January 2005 to May 2012 and is a unique example of a political blog using a single official media. This blog switched in the period of the study from being a personal blog to a political blog. The posts were divided into two different phases: the former were intended to discuss political topics and were written by a not‐yet‐political contributor; the latter were posts written by an active politician. Content analysis using simple word and sentence counts for every year of posts was undertaken, along with a readability analysis using the Microsoft Word Spelling and Grammar function, and both the Gunning Fog Index and the Gulpease Index. The two different phases were compared to determine if any change occurred in readability, complexity of the text, and volume of communication. In this way, we can explore the differences in the communication techniques used in the political field unofficially and then officially. Finally, our findings indicate that levels of readability of communications, particularly among broad‐based audiences, may be deteriorating significantly when the blog becomes a political one and the communication becomes more institutional. Copyright © 2013 John Wiley & Sons, Ltd.
Preserving cognitive function in epilepsy
Authors: Lanyon Karen
Published: June 2013

Our series of Commentaries from the Primary Care Neurology Society (P‐CNS) provide a primary care perspective on neurology articles featured in Progress. Here, Dr Karen Lanyon discusses the issues raised in ‘Beyond seizures: understanding cognitive deficits in epilepsy’ (see page 31 of this issue).
Continuation therapy for mania: a survey of psychiatrists' current practice
Authors: Young Allan H , Macritchie Karine AN
Published: June 2013

During the Lundbeck satellite symposium at the 12th Latest Advances in Psychiatry meeting in March, Professor Young and Dr Macritchie conducted an audience survey to assess current practice with regard to the duration of continuation treatment following an episode of mania among psychiatrists and the factors that might influence it. This report summarises the main findings of the survey.
Shocks and Coping Strategies in the Urban Squatter Settlements of San Salvador
Authors: Échevin Damien , Tejerina Luis
Published: June 2013

This article provides an assessment of shocks and coping strategies in the urban squatter settlements of San Salvador. Using a multi‐shocks household survey, it is shown that shocks like flooding, landslide, increase in food prices, insecurity, and illness or serious casualty prevail in these areas. Regression results show no significant effects of shocks on current consumption, which may indicate the existence of household consumption‐smoothing behavior. Hence, although coping responses to shocks may be efficient in the short term, covariate shocks may have adverse effects on well‐being in the longer run, especially if households decide to lower food, health, or education expenditures. Indeed, behavior‐based strategies appear to be very common when the shock is an increase in food prices, whereas assistance‐based strategies are more common when households are hit by flooding or landslide.
The Food Stamps Program and Economic Security Among Low‐Income Families, Part II: The Effects of Labor and Income
Authors: Wagle Udaya R.
Published: June 2013

This article is the second part of the analysis on this title, the first of which was published in issue 4.4 of this journal. Using a combination of family‐level micro data and state‐level macro indicators, the goal is to examine the roles of the Food Stamps Program (FSP) in promoting economic security during 2004 and 2007. To account for endogeneity and self‐selection bias likely in models of labor supply, income, and poverty using survey data, panel data models are estimated by instrumenting FSP receipts with TANF receipts at the family level and FSP participation rates at a specific geographic level. While substantiating the widely recognized work‐disincentive effects of FSP, results support its income‐enhancing effects on one hand and poverty‐increasing effects on the other. These seemingly contradictory results reaffirm that FSP supports are typically inadequate to make a significant dent in the economic insecurity of poor families even though they help promote economic security among low‐income but non‐poor families.
A compound‐based computational approach for the accurate determination of hot spots
Authors: Wang Lincong , Hou Yaqin , Quan Haihua , Xu Weiwei , Bao Yongli , Li Yuxin , Fu Yuan , Zou Shuxue
Published: June 2013

A plethora of both experimental and computational methods have been proposed in the past 20 years for the identification of hot spots at a protein–protein interface. The experimental determination of a protein–protein complex followed by alanine scanning mutagenesis, though able to determine hot spots with much precision, is expensive and has no guarantee of success while the accuracy of the current computational methods for hot‐spot identification remains low. Here, we present a novel structure‐based computational approach that accurately determines hot spots through docking into a set of proteins homologous to only one of the two interacting partners of a compound capable of disrupting the protein–protein interaction (PPI). This approach has been applied to identify the hot spots of human activin receptor type II (ActRII) critical for its binding toward Cripto‐I. The subsequent experimental confirmation of the computationally identified hot spots portends a potentially accurate method for hot‐spot determination in silico given a compound capable of disrupting the PPI in question. The hot spots of human ActRII first reported here may well become the focal points for the design of small molecule drugs that target the PPI. The determination of their interface may have significant biological implications in that it suggests that Cripto‐I plays an important role in both activin and nodal signal pathways.
Resistive switching characteristics of sol–gel based ZnO nanorods fabricated on flexible substrates
Authors: Park Soyun , Lee Jae Hyuk , Kim Hee‐Dong , Hong Seok Man , An Ho‐Myoung , Kim Tae Geun
Published: June 2013

The authors report the resistive switching characteristics of sol–gel based ZnO nanorods (NRs) fabricated on flexible substrates. A resistance ratio of 10, endurance of over 100 cycles, and narrower dispersion in the ON/OFF voltages and resistances compared to ZnO thin‐film devices are demonstrated. Furthermore, the resistive switching characteristics on flexible substrates are maintained under severe substrate bending because of the ductile properties of the nanorods. Devices composed of the Au/sol–gel based NRs/Au structure have the potential for low‐temperature flexible nonvolatile memory applications. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photodynamic oxidation of Staphylococcus warneri membrane phospholipids: new insights based on lipidomics
Authors: Alves Eliana , Melo Tânia , Simões Cláudia , Faustino Maria A. F. , Tomé João P. C. , Neves Maria G. P. M. S. , Cavaleiro José A. S. , Cunha Ângela , Gomes Newton C. M. , Domingues Pedro , Domingues M. Rosário M. , Almeida Adelaide
Published: June 2013

RATIONALE

The photodynamic process involves the combined use of light and a photosensitizer, which, in the presence of oxygen, originates cytotoxic species capable of oxidizing biological molecules, such as lipids. However, the effect of the photodynamic process in the bacterial phospholipid profile by a photosensitizer has never been reported. A lipidomic approach was used to study the photodynamic oxidation of membrane phospholipids of Staphylococcus warneri by a tricationic porphyrin [5,10,15‐tris(1‐methylpyridinium‐4‐yl)‐20‐(pentafluorophenyl)porphyrin triiodide, Tri‐Py+‐Me‐PF].

METHODS

S. warneri (108 colony forming units mL–1) was irradiated with white light (4 mW cm–2, 21.6 J cm–2) in the presence of Tri‐Py+‐Me‐PF (5.0 μM). Non‐photosensitized bacteria were used as control (irradiated without porphyrin). After irradiation, total lipids were extracted and separated by thin‐layer chromatography (TLC). Isolated fractions of lipid classes were quantified by phosphorus assay and analyzed by mass spectrometry (MS): off‐line TLC/ESI‐MS, hydrophilic interaction (HILIC)‐LC/MS and MS/MS.

RESULTS

The most representative classes of S. warneri phospholipids were identified as phosphatidylglycerols (PGs) and cardiolipins (CLs). Lysyl‐phosphatidylglycerols (LPGs), phosphatidylethanolamines (PEs), phosphatidylcholines (PCs) and phosphatidic acids (PAs) were also identified. After photodynamic treatment, an overall increase in the relative abundance of PGs was observed as well as the appearance of new oxidized species from CLs, including hydroxy and hydroperoxy derivatives. Formation of high amounts of lipid hydroperoxides was confirmed by FOX2 assay. Photodynamic oxidation of phospholipid standards revealed the formation of hydroperoxy and dihydroperoxy derivatives, confirming the observed CL oxidized species in S. warneri.

CONCLUSIONS

Membrane phospholipids of S. warneri are molecular targets of the photoinactivation process induced by Tri‐Py+‐Me‐PF. The overall modification in the relative amount of phospholipids and the formation of lipid hydroxides and hydroperoxides indicate the lethal damage caused to photosensitized bacterial cells. Copyright © 2013 John Wiley & Sons, Ltd.
The Effect of Argumentative Task Goal on the Quality of Argumentative Discourse
Authors: GARCIA‐MILA MERCE , GILABERT SANDRA , ERDURAN SIBEL , FELTON MARK
Published: June 2013

In argumentative discourse, there are two kinds of activity–dispute and deliberation–that depend on the argumentative task goal. In dispute the goal is to defend a conclusion by undermining alternatives, whereas in deliberation the goal is to arrive at a conclusion by contrasting alternatives. In this study, we examine the impact of these tasks goals on the quality of argumentative discourse. Sixty‐five junior high school students were organized into dyads to discuss sources of energy. Dyads were formed by members who had differing viewpoints and were distributed to one of two conditions: 31 dyads were asked to discuss with the goal to persuade the partner, and 34 were asked to reach consensus. Argumentation was analyzed using a schema based on Toulmin (1958). Eleven different argumentative structures resulted from the combination of Toulmin's basic elements. Students in the consensus group scored significantly higher than students in the persuasion group in 5/6 argumentative structures that included rebuttals. The major implication of the present work is that, similar to Mercer's (2000) claim about types of classroom conversation, not all classroom argumentation tasks promote scientific reasoning equally. © 2013 Wiley Periodicals, Inc. Sci Ed 97:497–523, 2013
The Relationship Between Time Allocated for Science in Elementary Schools and State Accountability Policies
Authors: JUDSON EUGENE
Published: June 2013

In the United States, student achievement results from mathematics and reading are always included in high‐stakes accountability calculations. Because of this, it has been argued that other subjects have been minimized due to assessment and accountability policies. In this study, the accountability practices of states were differentiated into three groups based on the degree to which science achievement contributed to accountability formulas. Data from National Assessment of Educational Progress Teacher Questionnaires were evaluated to assess the amount of time fourth‐grade teachers devoted to mathematics and reading in 2003 and 2011, as well as to science in 2005 and 2009. Teachers from the three groups of states reported spending equivalent amounts of time on mathematics and reading. However, the frequency of teachers reporting spending at least 4 hours of weekly instructional time on science was significantly higher in states that integrated fourth‐grade science achievement into accountability formulas versus states where science did not figure in high‐stakes accountability. Implications of this significant difference are discussed and are related to states’ applications to receive waivers from No Child Left Behind and to alignment with the goals of the Next Generation Science Standards. © 2013 Wiley Periodicals, Inc. Sci Ed 97:621–636, 2013
Love It or Leave It: Norwegian Students’ Motivations and Expectations for Postcompulsory Physics
Authors: BØE MARIA VETLESETER , HENRIKSEN ELLEN KAROLINE
Published: June 2013

In response to insufficient participation and female underrepresentation in physics education, this article uses questionnaire data from Norwegian physics students in upper secondary (N = 585) and first‐year tertiary (N = 278) education to characterize the “physics choosers.” An expectancy‐value perspective is adopted to describe the motivations and expectations behind the respondents’ physics choice. Three choice profiles were identified among secondary students. The intrinsic and extrinsic profile, broadly motivated by interest‐enjoyment, expectation of success, and utility for university admission; the extrinsic profile emphasizing mainly utility; and the intrinsic profile emphasizing mainly interest‐enjoyment. Females were underrepresented in the intrinsic profile. Many secondary students did not know what kind of job they wanted, but those who did, aspired to go into medicine (particularly females) or engineering (particularly males). Tertiary students were motivated by a passion for physics and high expectation of enjoyment, and many of them planned to go into research. Tertiary students were more likely than secondary students to value idealistic purposes in a future career. The results imply that participation in physics may be improved by targeting students with a broader motivation than interest alone, through inclusive classroom practices, support of students’ self‐concepts, and examples of physics applications and physics‐related careers available. © 2013 Wiley Periodicals, Inc. Sci Ed 97:550–573, 2013
Publishing and sharing encrypted data with potential friends in online social networks
Authors: Shuai Huimin , Zhu Wen Tao , Liu Xin
Published: June 2013

Making friends by publishing and sharing personal data in a special interest group has become popular in online social networks. Data security is a major concern, as digital content can be easily accessed from all over the Internet, and the online social network service provider is often for profit and semi‐trusted. The standard solution to data security is encryption, but sharing of encrypted data then becomes a challenging task. In this paper, employing attribute‐based encryption (ABE), we propose Masque+, a novel hierarchical and fine‐grained access control mechanism. On the basis of key policy ABE, the service provider manages users on the system level, but without being able to access their sensitive data. On the basis of ciphertext policy ABE, members of an interest group may customize their own access policies specifically. Masque+ features pragmatic functionalities like user revocation on the system level and the group level, respectively. We also build a prototype to validate the cryptographic algorithms involved in Masque+ and evaluate their performances. Real experimental data show that Masque+ incurs fairly reasonable costs even in cases where the access control policy is significantly complex. Copyright © 2013 John Wiley & Sons, Ltd.
Hypoxia induces re-entry of committed cells into pluripotency
Authors: Mathieu Julie , Zhang Zhan , Nelson Angelique , Lamba Deepak A. , Reh Thomas A. , Ware Carol , Ruohola-Baker Hannele
Published: June 2013

Adult stem cells reside in hypoxic niches, and embryonic stem cells (ESCs) are derived from a low oxygen environment. However, it is not clear whether hypoxia is critical for stem cell fate since for example human ESCs (hESCs) are able to self-renew in atmospheric oxygen concentrations as well. We now show that hypoxia can govern cell fate decisions since hypoxia alone can revert hESC- or iPSC-derived differentiated cells back to a stem cell-like state, as evidenced by re-activation of an Oct4-promoter reporter. Hypoxia-induced “de-differentiated” cells also mimic hESCs in their morphology, long-term self-renewal capacity, genome-wide mRNA and miRNA profiles, Oct4 promoter methylation state, cell surface markers TRA1–60 and SSEA4 expression, and capacity to form teratomas. These data demonstrate that hypoxia can influence cell fate decisions and could elucidate hypoxic niche function.
MicroRNA-200C and -150 play an important role in endothelial cell differentiation and vasculogenesis by targeting transcription repressor ZEB1
Authors: Luo Zhenling , Wen Guanmei , Wang Gang , Pu Xiangyuan , Ye Shu , Xu Qingbo , Wang Wen , Xiao Qingzhong
Published: June 2013

To investigate the role of miRNA in controlling human embryonic stem (hES) cell differentiation toward the endothelial lineage and chick embryonic blood vessel formation, undifferentiated hES cells were first cultured on Matrigel-coated flasks and in endothelial cell growth medium-2 (EGM-2) to initiate endothelial cell (EC) differentiation. CD146+ cells were isolated from differentiating hES cells and expanded in vitro. The in vitro expanded CD146+ cells were positive for EC markers, capable of Ac-LDL uptake, lectin binding, and the formation of vascular structures in vitro and in vivo. miRNA gain/loss-of-function analyses revealed that miR-150 and miR-200c were crucial in EC differentiation. Transcriptional repressor zinc finger E-box-binding homeobox 1 (ZEB1) was identified as the communal target gene of miRNA-200C and −150, and inhibition of ZEB1 was required for miRNA-200C or −150 mediated EC gene expressions. Moreover, we demonstrated that ZEB1 could transcriptionally repress EC gene expression through direct binding to promoters of EC genes. Finally, we also demonstrated that miRNA-200c and −150 played an important role in chick embryonic blood vessel formation by in vivo inhibition of miRNA-200C or −150 in developing chick embryos, and blocking ZEB1 signaling in CD146-positive cells could rescue the inhibitory effects of miR-200c inhibiton in in vivo vasculogenesis. Our findings revealed that miR-150 and miR-200c play an important role in human endothelial lineage specification and chick embryonic vasculogenesis by targeting ZEB1.
Defined extracellular matrix components are necessary for definitive endoderm induction
Authors: Taylor-Weiner Hermes , Schwarzbauer Jean E. , Engler Adam J.
Published: June 2013

Differentiation methods often rely exclusively on growth factors to direct mouse embryonic stem cell (ESC) fate, but the niche also contains fibrillar extracellular matrix (ECM) proteins, including fibronectin (FN) and laminin, which could also direct cell fate. Soluble differentiation factors are known to increase ECM expression, yet ECM's ability to direct ESC fate is not well understood. To address the extent to which these proteins regulate differentiation when assembled into a matrix, we examined mouse ESC embryoid bodies (EBs) and found that their ability to maintain pluripotency marker expression was impaired by soluble serum FN. EBs also showed a spatiotemporal correlation between expression of FN and GATA4, a marker of definitive endoderm (DE), and an inverse correlation between FN and Nanog, a pluripotency marker. Maintenance of mouse ESC pluripotency prevented fibrillar matrix production, but induction medium created lineage-specific ECM containing varying amounts of FN and laminin. Mouse ESC-derived matrix was unlike conventional fibroblast-derived matrix, which did not contain laminin. Naïve mouse ESCs plated onto ESC- and fibroblast-derived matrix exhibited composition-specific differentiation. With exogenously added laminin, fibroblast-derived matrix is more similar in composition to mouse ESC-derived matrix and lacks residual growth factors that mouse ESC matrix may contain. Naïve mouse ESCs in DE induction medium exhibited dose-dependent DE differentiation as a function of the amount of exogenous laminin in the matrix in an α3 integrin-dependent mechanism. These data imply that fibrillar FN is necessary for loss of pluripotency and that laminin within a FN matrix improves DE differentiation.
Constitutive activation of RANK disrupts mammary cell fate leading to tumorigenesis
Authors: Pellegrini Pasquale , Cordero Alex , Gallego Marta Ines , Dougall William C. , Purificación Muñoz , Pujana Miguel Angel , Gonzalez-Suarez Eva
Published: June 2013

Receptor Activator of NF-kappa B (RANK) pathway controls mammary gland development in mice but its role in mammary stem cell fate remains undefined. We show that constitutive RANK signaling expands luminal and basal mammary compartments including mammary stem and luminal progenitor cell pools and interferes with the generation of CD61+ and Sca1+ luminal cells and Elf5 expression. Impaired mammary cell commitment upon RANK overexpression leads to the accumulation of progenitors including K14+K8+ bipotent cells and the formation of heterogeneous tumors containing hyperplastic basal, luminal, and progenitor cells. RANK expression increases in wild-type mammary epithelia with age and parity, and spontaneous preneoplastic lesions express RANK and accumulate K14+K8+ cells. In human breast tumors, high RANK expression levels are also associated with altered mammary differentiation. These results suggest that increased RANK signaling interferes with mammary cell commitment, contributing to breast carcinogenesis.
Osteoblast-Targeted suppression of PPARγ increases osteogenesis through activation of mTOR signaling
Authors: Sun Hongli , Kim Jin Koo , Mortensen Richard , Mutyaba Lorraine P. , Hankenson Kurt D. , Krebsbach Paul H.
Published: June 2013

Nuclear receptor peroxisome proliferator-activated receptor-γ (PPARγ) is an essential transcription factor for adipocyte differentiation. In mesenchymal stem cells, PPARγ has been assumed to play a negative role in osteoblastic differentiation, by working in an adipogenesis dependent manner, due to the reciprocal relationship between osteoblast and adipocyte differentiation. However, the direct role of PPARγ in osteoblast function is not fully understood, due in part to inadequate model systems. Here, we describe an adenoviral-mediated PPARγ knockout system in which suppression of PPARγ in mesenchymal stem cells enhanced osteoblast differentiation and inhibited adipogenesis in vitro. Consistent with this in vitro observation, lipoatrophic A-ZIP/F1 mice, which do not form adipocytes, displayed a phenotype in which both cortical and trabecular bone was significantly increased compared with wild-type mice. We next developed an inducible osteoblast-targeted PPARγ knockout (Osx Cre/flox- PPARγ) mouse to determine the direct role of PPARγ in bone formation. Data from both in vitro cultures of mesenchymal stem cells and in vivo µCT analysis of bones suggest that suppression of PPARγ activity in osteoblasts significantly increased osteoblast differentiation and trabecular number. Endogenous PPARγ in mesenchymal stem cells and osteoblasts strongly inhibited Akt/mammalian target of rapamycin (mTOR)/p70S6k activity and led to decreased osteoblastic differentiation. Therefore, we conclude that PPARγ modulates osteoblast differentiation and bone formation through both direct and indirect mechanisms. The direct mode, as shown here, involves PPARγ regulation of the mTOR pathway, while the indirect pathway is dependent on the regulation of adipogenesis.
A gentle critique of the Greenhouse Development Rights framework
Authors: Shockley Kenneth E.
Published: June 2013

The Greenhouse Development Rights (GDR) framework provides a promising attempt at fairly distributing the burdens of climate change. This brief review critically examines the framework, with a particular focus on the individualism that the authors take to provide much of the moral justification for their account. The review concludes that the particular role played by individualism in GDR both blinds the framework to certain crucial features of development and leads to difficulties in attributing historical emissions more properly tied to states and collective entities than to individuals. WIREs Clim Change 2013, 4:225–231. doi: 10.1002/wcc.215

This article is categorized under:

Climate, Nature, and Ethics > Climate Change and Global Justice
Lost in the problem: the role of boundary organisations in the governance of climate change
Authors: Hoppe Rob , Wesselink Anna , Cairns Rose
Published: June 2013

In this article, we explore how climate change science is connected to climate change governance. When formally institutionalized, as in Intergovernmental Panel on Climate Change (IPCC) or UN Framework Convention on Climate Change (UNFCCC), these sites may be referred to asboundary organizations. These institutions engage not only in the quality assessment of scientific research, but also in the design of innovative policy instruments, or evaluation of policy impacts—activities that we refer to asboundary work. Boundary work is inherently ‘tricky business’. Science and politics are normally demarcated spheres with different sacred stories. Scientists aspire to ‘speak truth to power’, while policymakers want ‘politics on top and science on tap’. Boundary work endeavors to coordinate these apparently incompatible aspirations. In this article, we describe, analyze, and assess whether, to what extent, and how the major international and some national boundary organizations in climate change governance have been able to avoid over‐politicization and over‐scientization. We demonstrate that the nature and success of boundary organizations and the ways they work depend on: (1) the degree to which the climate change problem is defined as ‘wicked’ or unstructured, or as (relatively) ‘tame’ and structured; (2) the stage of the policy process; and (3) characteristics of the policy network and the socio‐political context: the degree to which relevant players insist on strict separation and a linear relation from science to politics, or, alternatively, are tolerant of a blurring of the boundaries and hence a two‐way, coproductive relation between science and politics. Anna Wesselink's contribution to this article was financially supported by the European Union (European Commission, European Reintegration Grant PERG08‐GA‐2010‐276934).WIREs Clim Change2013, 4:283–300. doi: 10.1002/wcc.225

This article is categorized under:

Policy and Governance > Multilevel and Transnational Climate Change Governance

Social Status of Climate Change Knowledge > Climate Science and Decision Making
Contrasting frames in policy debates on climate change adaptation
Authors: Dewulf Art
Published: June 2013

The process by which issues, decisions, or events acquire different meanings from different perspectives has been studied as framing. In policy debates about climate change adaptation, framing the adaptation issue is a challenge with potentially far‐reaching implications for the shape and success of adaptation projects. From the available literature on how the meaning of climate change adaptation is constructed and debated, three key dimensions of frame differences were identified: (1) the tension between adaptation and mitigation as two contrasting but interrelated perspectives on climate change; (2) the contrast between framing climate change adaptation as a tame technical problem, and framing climate change as a wicked problem of governance; and (3) the framing of climate change adaptation as a security issue, contrasting state security frames with human security frames. It is argued that the study of how climate change adaptation gets framed could be enriched by connecting these dimensions more closely with the following themes in framing research: (1) how decision‐making biases that to framing issues as structured technical problems; (2) the process of scale framing by which issues are situated at a particular scale level; and (3) the challenge of dealing with the variety of frames in adaptation processes.WIREs Clim Change2013, 4:321–330. doi: 10.1002/wcc.227

This article is categorized under:

Perceptions, Behavior, and Communication of Climate Change > Social Amplification/Attenuation of Climate Risks

Vulnerability and Adaptation to Climate Change > Values‐Based Approach to Vulnerability and Adaptation
Lessons from adaptation to sustain freshwater environments in the Murray–Darling Basin, Australia
Authors: Pittock J.
Published: June 2013

Governance of Australia's Murray–Darling Basin (the Basin) is frequently lauded as an example to other river managers globally. Freshwater environments in the Basin are particularly vulnerable to water scarcity and change. In this paper, governmental responses are assessed to draw global lessons on climate change adaptation for rivers. A range of climate change adaptation measures for freshwater ecosystem conservation in the Basin are outlined namely: higher, long‐term allocations of water to the environment; reviewing water allocation on a cyclical basis; allocating an equal or greater share of available water to the environment in dry years; and environmental works and measures to use less water to conserve wetlands. Examples of poor translation of science into policy that do not adequately consider the risks, costs, and benefits of adaptation interventions are explored. Adaptation policy in the Basin illustrates the risks of heavy reliance on infrastructure, of the high costs of trade‐offs between environmental measures versus socio‐economic and political concerns, and of dependence on too few measures. Lessons include the need for rigorous evaluation of risks, costs, and benefits to minimize perverse outcomes, and for adequate incentives and penalties for implementation of adaptation policies across governance scales. It is concluded that rather than a focus on only a few interventions, such as environmental flows, better adaptation practice requires deployment of a suite of different but complementary measures that spreads risk and maximizes resilience to climate variability and change. WIREs Clim Change 2013, 4:429–438. doi: 10.1002/wcc.230

This article is categorized under:

Vulnerability and Adaptation to Climate Change > Learning from Cases and Analogies
Joint resource reconfiguration and robust routing for cognitive radio networks: a robust optimization approach
Authors: Xue Liang , Yang Bo , Zhao Jijun , Liu Zhixin , Guan Xinping
Published: June 2013

Cognitive radio (CR) networks comprise a number of spectrum agile nodes with the capability of spectrum detection. Applying techniques of spectrum sharing in CR networks can achieve the efficient utilization of network resources. Usually, data rates of user sessions are time varied because of the dynamic behaviors of CR networks. It is expected that the occurrence of link outage should be avoided and incorporated into the routing design under conditions of increasingly crowded spectrum. This paper proposes an integral framework, which considers these two correlated schemes (resource reconfiguration and robust routing) simultaneously. For that, the resource reconfiguration scheme is developed for the efficient usage of network resources and aims at reducing the occupancy of licensed bands. The link outage, resulting from random session rate, is confined within an acceptable range by using strategy of virtual ‘network portfolio’. A robust optimization approach is proposed to guarantee reliable data transmission among possible interfering links. Both these two items (resource reconfiguration and robust routing) are formulated in a framework of cross‐layer optimization. The evolutionary process of CR network states is provided in simulations, where the results show that the joint design proposal can achieve the least interferences among different licensed users while realizing robust routing. Copyright © 2013 John Wiley & Sons, Ltd.
Optimal Markov chain Monte Carlo sampling
Authors: Chen Ting‐Li
Published: June 2013

This article is a review article on the optimal Markov chain Monte Carlo (MCMC) sampling. The focus is on homogeneous Markov chains. This article first reviews the problem of finding the optimal transition matrix, which is defined to minimize the asymptotic variance of MCMC estimators. The article later reviews the locally optimal sampler (LOS), an MCMC sampling that performs local updates based on the optimal transition matrix. We conducted a simulation study to compare the LOS with the Metropolis–Hastings and the Gibbs Sampler. The LOS was shown to provide an improved rate of convergence over these two most popular sampling schemes. The implementation of the LOS requires only minor modifications in existing Gibbs sampling code. WIREs Comput Stat 2013. doi: 10.1002/wics.1265

This article is categorized under:

Statistical and Graphical Methods of Data Analysis > Markov Chain Monte Carlo (MCMC)
Percutaneous Flexible Double Pinning (Py–Desmanet's Procedure) for Pediatric Distal Radius Fractures
Authors: Sano Kazufumi , Hashimoto Tomohisa , Kimura Kazumasa , Ozeki Satoru
Published: June 2013

Purpose

The purpose of this study is to report the results of percutaneous flexible double pinning for pediatric distal radius fractures.

Methods

Thirteen unstable fractures (three physeal and ten metaphyseal) of the distal radius in which the physeal plate could be still identified were treated with percutaneous flexible double pinning between 2008 and 2011. The average age of these cases was 9.8 years (range, 2–16 years). According as Py–Demanet's original technique, the fracture was fixed with two percutaneous transepiphyseal intramedullary wires. Kirschner wires or c-wires of 1.4–1.6 mm in diameter were used in each case depending on age. Operative and short follow-up outcomes were assessed.

Results

The average operative duration was 23 min (range, 5–45 min). Comorbid distal ulnar fractures were further stabilized by intramedullary pinning. Additional external splintage was administered in all cases for 6 weeks postoperatively. Wires were removed after an average of 7.2 weeks (range, 4–10 weeks). Bone union was achieved in all cases. Neither malunion nor early epiphyseal closure of the distal radius was identified at mean follow-up of 12 months (range, 3–51 months).

Discussion

Flexible double pinning has been successfully used for distal radius fractures in adults. Since this technique is minimally invasive, quick, and technically easy, it is also a good treatment option for unstable distal radius fractures in children. Level of clinical evidence: Therapeutic Level IV