bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the Emergence of RNA
Authors: Krishnamurthy Ramanarayanan 
Published: February 2015

AbstractWhether there was an RNA world or not, it is indisputable that there was RNA; when, where, and how is yet to be settled. The question of whether “pristine” RNA assembled directly from its components (“prebiotic clutter”), or whether it was a descendant of “simpler” ancestral system(s), is central to the ongoing debate about RNA’s origins. In this review, we look at the facts that suggest RNA is an emergent system and that each component of RNA may have been decided at the level of the oligomer/polymer, and not at the level of the prebiotic clutter, nor at the level of monomer nucleotides. The critical interdependence of RNA’s components – ribofuranose, phosphodiester backbone, and purine‐pyrimidine base‐pairing – for the functioning of RNA seems to be evident, and manifests itself only at the level of the polymer. Based on the power of such nuanced selections at the polymer level, and coupling it with the reality of the prebiotic mixtures at the monomer level, a scenario is presented wherein the combinatorial interactions of diverse prebiotic (systems) chemistry leads first to chimeric‐heterogeneous (aka “pre‐RNA”) systems, which can usher in a homogeneous system (RNA), capable of further evolution.
Randomized study of teaching ultrasound‐guided vascular cannulation using a phantom and the freehand versus needle guide–assisted puncture techniques
Authors: Jaffer Usman , Normahani Pasha , Singh Prashant , Aslam Mohammed , Standfield Nigel J. 
Published: February 2015

ABSTRACTPurposeThe task of ultrasound‐guided vessel cannulation can be technically difficult. Needle guides have been designed to facilitate vessel puncture. We aimed to identify and compare the learning curves of participants performing vessel puncture with conventional freehand (FH) and needle guide–assisted (NG) techniques.MethodsThirty‐six participants were randomly allocated to either the FH or the NG group. They were asked to consecutively perform as many as 30 vessel punctures on a simulated phantom model. Quantitative metrics (time taken and number of skin and posterior‐wall punctures) were recorded and compared between the two groups. The cumulative sum and moving F‐test statistical methods were used to delineate the learning curves.ResultsThere was a significantly lower rate of posterior‐wall punctures in the NG group than in the FH group (15% versus 26%; p < 0.0001). Participants in the NG group also performed significantly fewer skin punctures than did those in the FH group (mean, 405 versus 515; p < 0.0001). Cumulative sum statistical method analysis showed that participants in the NG group surmounted the learning curve earlier (13 attempts; interquartile range, 10.3–17.0) than did those in the FH group (19 attempts; interquartile range, 15.0–27.5). The number of attempts to surmount the learning curve was significantly less for the FH group (7.2 versus 16 attempts; p = 0.007) when using the moving F‐test.ConclusionsThe NG puncture allows a greater number of trainees to cross the learning threshold and offers the advantages of fewer posterior‐wall punctures and skin punctures. The use of NG puncture may result in a shorter path to proficiency, allowing trainees to attempt needle puncture earlier and with a greater degree of safety. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 43:469–477 2015
Sonographic appearances of torsion of the appendix testis and appendix epididymis in children
Authors: Lev Mikahl , Ramon Jacob , Mor Yoram , Jacobson Jeffrey M. , Soudack Michalle 
Published: February 2015

ABSTRACTPurposeThe most common cause of acute scrotum in prepubertal boys is torsion of the testicular or epididymal appendages. The purpose of this retrospective study was to characterize the features of these lesions as viewed on sonographic (US) and color Doppler US examination.MethodsDuring a 220‐week period, 527 male patients 0–17 years old had been referred from the pediatric emergency department for scrotal US evaluation. Torsion of the appendix testis or appendix epididymis had been diagnosed in 19 (3.6%) patients, 3–14 years old (mean, 9.4 years); those patients became our study cohort. The clinical diagnoses in 15 of those patients had been suspected testicular torsion (n = 7), trauma (n = 4), suspected epididymitis and/or orchitis (n = 3), and suspected hydrocele (n = 1). The remaining four patients had been referred owing to nonspecific pain. None of the 19 patients had had the “blue‐dot sign” on physical examination.ResultsIn the 19 patients diagnosed with torsion of the intrascrotal appendages, color Doppler US demonstrated a round or oval avascular lesion with heterogeneous echotexture (n = 18), posterior enhancement (n = 13), and hyperemia of the surrounding structures (n = 15). All lesions (appendages) were adjacent (n = 16) or in close proximity (n = 3) to the upper pole of the testis. Fifteen of the appendages were adjacent to both the testis and the epididymis, four were adjacent to the epididymis alone, and none were adjacent to the testis alone. Owing to the close proximity of the upper pole of the testis, the epididymis, and the appendage, differentiation between testicular and epididymal appendages was not possible.ConclusionsTorsion of the intrascrotal appendages has a typical appearance on color Doppler US; thus, we believe that it is the method of choice for diagnosing torsion of the scrotal appendages and safely ruling out other disorders as well as avoiding unwarranted surgical intervention or antibiotic treatment. © 2015 Wiley Periodicals, Inc. J Clin Ultrasound 43:485–489 2015
Do Democracies Tax More? Political Regime Type and Taxation
Authors: Garcia Maria Melody , von Haldenwang Christian 
Published: February 2015

AbstractA growing body of literature suggests that political regime type matters in determining taxation. However, research on the relationship of political regimes to taxation yields mixed results. To what extent does the democratic or authoritarian character of the polity impact on the level of taxation? The paper investigates the relationship between political regimes and tax‐to‐gross domestic product ratio, using a panel dataset of 131 countries and covering the period 1990–2008. Findings suggest that the character of the polity affects taxation, but there is no linear trend in favour of democracy. Rather, the results indicate a U‐shaped relationship between polity and tax ratio. Copyright © 2015 John Wiley & Sons, Ltd.
Impact of the processes of testicular regression and recrudescence in the prostatic complex of the bat Myotis nigricans (Chiroptera: Vespertilionidae)
Authors: Beguelini Mateus R. , Góes Rejane M. , Rahal Paula , Morielle‐Versute Eliana , Taboga Sebastião R. 
Published: February 2015

ABSTRACTMyotis nigricans is a species of vespertilionid bat, whose males show two periods of total testicular regression during the annual reproductive cycle in the northwest São Paulo State, Brazil. Thus, the aim of this study was to investigate the impact of total testicular regression on the prostatic morphophisyology and its regulation. The prostatic complex (PC) of animals from the four periods of the reproductive cycle (active, regressing, regressed, and recrudescence) was analyzed by different histological, morphometric, and immunohistochemical procedures to characterize its variations, analyze its hormonal regulation and evaluate whether the prostate is affected by the processes of testicular regression and recrudescence. The results indicated a decrease in the prostatic parameters from the active to regressed periods, which are related to decreases in the testicular production of testosterone and in the prostatic expression of androgen receptor (AR), estrogen receptor α (ERα) and aromatase. However, in regressed‐recrudescence periods, the prostatic expression of AR, ERα and aromatase increased, indicating the reactivation of the PC. Despite this, the PC appears to have a slower reactivation and seems not to follow the testicular recrudescence in morphological and morphometric terms. With these data, we demonstrate that the prostatic physiology is directly affected by total testicular regression and conclude that it is regulated by testosterone and estrogen, via the production of testosterone by the testes, its conversion to dihydrotestosterone by 5α‐redutase and to estrogen by aromatase, and the activation/deactivation of AR and ERα in epithelial cells, which regulate cell expression and proliferation. J. Morphol. 276:721–732, 2015. © 2015 Wiley Periodicals, Inc.
Setup of a bone aging experimental model in the rabbit comparing changes in cortical and trabecular bone: Morphological and morphometric study in the femur
Authors: Pazzaglia Ugo E. , Sibilia Valeria , Congiu Terenzio , Pagani Francesca , Ravanelli Marco , Zarattini Guido 
Published: February 2015

ABSTRACTBone aging was studied in an experimental model (rabbit femur) in three populations aged 0.5, 1.5, and 7.5 years. Cortical bone histology was compared with a data set from a 1.5‐month‐old population of an earlier published paper. From 0.5‐year‐old onward, the mean femur length did not increase further. Thereafter, the mean marrow area increased and the cortical area decreased significantly with aging. This was associated with a structural pattern transformation from plexiform to laminar and then Haversian‐like type. The distal meta‐epiphysis bone trabecular density of the oldest populations also was significantly lower in specific regions of interest (ROI). Percentage sealed primary vascular canals in laminar bone significantly increased with aging without variation of percentage sealed secondary osteons. Remodeling rate reflected by the density of cutting cones did not significantly change among the age populations. These data suggest that laminar bone vascular pattern is more functional in the fast diaphyseal expansion but not much streamlined with the renewal of blood flow during secondary remodeling. Bone aging was characterized by: 1) secondary remodeling subendosteally; 2) increment of sealed primary vascular canals number; 3) increased calcium content of the cortex; 4) cortical and trabecular bone mass loss in specific ROIs. Taken together, the present data may give a morphological and morphometric basis to perform comparative studies on experimental models of osteoporosis in the rabbit. J. Morphol. 276:733–747, 2015. © 2015 Wiley Periodicals, Inc.
Candidate Distributions for Climatological Drought Indices (SPI and SPEI)
Authors: Stagge James H. , Tallaksen Lena M. , Gudmundsson Lukas , Van Loon Anne F. , Stahl Kerstin 
Published: February 2015

AbstractThe Standardized Precipitation Index (SPI), a well‐reviewed meteorological drought index recommended by the World Meteorological Organization (WMO), and its more recent climatic water balance variant, the Standardized Precipitation‐Evapotranspiration Index (SPEI), both rely on selection of a univariate probability distribution to normalize the index, allowing for comparisons across climates. Choice of an improper probability distribution may impart bias to the index values, exaggerating or minimizing drought severity. This study compares a suite of candidate probability distributions for use in SPI and SPEI normalization using the 0.5° × 0.5° gridded Watch Forcing Dataset (WFD) at the continental scale, focusing on Europe. Several modifications to the SPI and SPEI methodology are proposed, as well as an updated procedure for evaluating SPI/SPEI goodness of fit based on the Shapiro–Wilk test. Candidate distributions for SPI organize into two groups based on their ability to model short‐term accumulation (1–2 months) or long‐term accumulation (>3 months). The two‐parameter gamma distribution is recommended for general use when calculating SPI across all accumulation periods and regions within Europe, in agreement with previous studies. The generalized extreme value distribution is recommended when computing the SPEI, in disagreement with previous recommendations.
Influence of homogenized residues of anaerobic digestate on the physicochemical properties of differently textured soils
Authors: Voelkner Amrei , Holthusen Dörthe , Horn Rainer 
Published: February 2015

AbstractBecause of the focus on renewable energy, new biogas digesters are being built with the consequence of an increased production of anaerobic digestates (AD) as a by‐product. Although they can be used as organic fertilizer on arable fields, negative impacts of these digestates also may occur. Therefore, it was the aim of this laboratory study to investigate the effect of a normally applied volume of 30 m3 ha−1 of anaerobic digestates derived from a ground input substrate of maize (Zea mays L.) , sugar beet (Beta vulgaris L.), and wheat (Triticum aestivum L.) in different ratios (100 /80 / 20%) on the properties of two soils. The soils, which were homogenized (sieved to ≤ 2 mm) and placed in columns with a defined bulk density of 1.45 g cm−3, were a Cambic Luvisol (sandy loam) derived from glacial till and a Podzol (sandy sand) derived from glazial outwash. Physicochemical parameters [pH, electrical conductivity (EC)] and the wetting behavior of the soils were analyzed by measuring the contact angle (CA) by using the Wilhelmy–Plate‐Method (WPM) and the Repellency Index (RI) from the sorptivity of water and ethanol. To determine the risk of soil dispersion as a consequence of digestate amendment, the amount of readily dispersible clay (RDC) was determined by detecting the turbidity of a soil suspension. The application of 30 m3 ha−1 of AD decreased the wettability of the sandy sand as compared to the untreated soil, while the wettability of the loamy sand remained unaffected by the digestate amendment. The amount of RDC was higher in the loamy sand compared to the sandy sand, but the AD‐amended soil did not exhibit a significant change in dispersibility. While the loamy soil exhibited acidification of the soil after digestate application, the sandy soil showed an alkalinization of soil columns. Overall, the soil texture was identified to be a main factor controlling the effect of the digestates on soil properties. The results of this lab study showed that this study can be used as a first approach for the quantification of digestate amendment under practical conditions.
Effect of different macronutrient cation ratios on macronutrient and water uptake by melon (Cucumis melo) grown in recirculating nutrient solution
Authors: Neocleous Damianos , Savvas Dimitrios 
Published: February 2015

AbstractThe aim of the present study was to determine uptake ratios between macronutrients and water for melon (Cucumis melo L. cv. Dikti) grown in a closed soilless cropping system. The obtained data can be used to establish standard nutrient solution compositions for melon crops grown in closed hydroponic systems under Mediterranean climatic conditions. Nutrient and water uptake by plants in the closed hydroponic system was compensated for by supplying replenishment nutrient solutions (RNS) differing either in the concentrations of K+, Ca2+, and Mg2+ or in their mutual ratio. The RNS, used as control treatment, had an electrical conductivity (EC) of 1.74 dS m−1 and contained 6.5 mM K+, 2.8 mM Ca2+, and 1.0 mM Mg2+ (K+ : Ca2+ : Mg2+ = 0.63 : 0.27 : 0.10). Control RNS was compared with two other RNS, both with a high Ca2+ level (4.2 mM). The K+ and Mg2+ levels in these two RNSs were: (1) not altered (corresponding to a ratio of K+ : Ca2+ : Mg2+ = 0.55 : 0.36 : 0.09; EC = 2.0 dS m−1) or (2) increased to maintain the same K+ : Ca2+ : Mg2+ ratio as in the control RNS (EC = 2.45 dS m−1). Nutrient to water uptake ratios, commonly termed uptake concentrations (UCs), were assessed by two alternative methods, i.e., (1) estimating the ratio between nutrient and water removal from the system or (2) estimating the ratio between the mass of the nutrient that was recovered from plant biomass and the water consumption. Over the two methods, mean UCs for N, P, K, Ca and Mg were 15.4, 1.31, 5.47, 3.78, and 1.02 mmol L−1, respectively, and tissue analysis resulted in a K : Ca : Mg molar ratio of = 0.55 : 0.34 : 0.11 in the whole plant. Moreover, the UCs tended to decrease as the crop aged although, in absolute values, the mass of nutrients absorbed increased following dry‐weight accumulation. Based on the obtained results, adapting the composition of the nutrient solution at least three times during the cropping period of melon is recommended. Further, the results revealed that the damage caused by the increase of the EC when attempting to maintain a target K+ : Ca2+ : Mg2+ ratio in the replenishment NS is higher than the benefits from the optimal cation ratio. Increasing K+ and Mg2+ concentration in addition to that of Ca2+ to maintain a standard K+ : Ca2+ : Mg2+ ratio raises the EC in the root zone (4.62 dS m−1), due to increased accumulation of nutrients, thereby reducing the mean fruit weight and concomitantly the total fruit yield (20% decrease). Leaf gas exchange, chlorophyll parameters and fruit taste quality were not influenced by the differences in macronutrient cation concentrations or ratios in the RNS, whereas phenolics and antioxidant capacity in melon fruit were enhanced by the increased root‐zone EC.
Involvement of nitrogen in salt resistance of Atriplex portulacoides is supported by split‐root experiment data and exogenous application of N‐rich compounds
Authors: Benzarti Maali , Rejeb Kilani Ben , Messedi Dorsaf , Abdelly Chedly , Debez Ahmed 
Published: February 2015

AbstractUsing a split‐root system, we aimed to identify the limiting factors for the growth of the halophyte Atriplex portulacoides L. under extreme salinity (800 mM NaCl) conditions. One half of the root system was immersed in complete nutrient solution at 0 or 800 mM NaCl and the other half was immersed in NaCl‐free medium, containing all nutrients or deprived of potassium (K+) or calcium (Ca2+) or nitrogen (N). Data indicate that at high salinity levels A. portulacoides growth is limited by the restrictions imposed by NaCl on N uptake. Next, the alleviation of the adverse impact by salt stress (800 mM NaCl) on plant growth was investigated through urea (U) and/or thiourea (TU) external addition through foliar application. Whether separately or supplied together, both components mitigated the negative impact of salinity on the plant growth by significantly improving the photosynthetic activity parameters [CO2 assimilation rate, stomatal conductance and maximum quantum efficiency of PSII photochemistry (Fv/Fm)], as well as shoot N concentration and the photosynthetic nitrogen‐use efficiency (PNUE). A concomitant increase of protein and free amino acid concentrations was also observed. As a whole, the present study highlights the significance of N in A. portulacoides response to high salinity and suggests that combined application of U and TU could promote the growth of this halophyte potentially useful for saline soil reclamation and revegetation purposes.
Effects of gestational age at enrollment in pregnancy exposure registries
Authors: Margulis Andrea V. , Mittleman Murray A. , Glynn Robert J. , Holmes Lewis B. , Hernández‐Díaz Sonia 
Published: February 2015

AbstractPurposeThis study aims to explore the influence of gestational age at enrollment, and enrollment before or after prenatal screening, on the estimation of drug effects in pregnancy exposure registries.MethodsWe assessed the associations between first trimester antiepileptic drug (AED) exposure and risk of spontaneous abortion and major congenital malformations in the North American AED Registry (1996–2013). We performed logistic regression analyses, conditional or unconditional on gestational age at enrollment, to estimate relative risk (RR) for first trimester AED users compared with non‐users. We also compared first trimester users of valproic acid and lamotrigine. Analyses were repeated in women who enrolled before prenatal screening.ResultsEnrollment occurred earlier among 7029 AED users than among 581 non‐users; it was similar among AEDs. Comparing AED users with non‐users, RR (95% confidence interval) of spontaneous abortion (n = 359) decreased from 5.1 (2.3–14.1) to 2.0 (0.9–5.6) after conditioning on gestational week at enrollment and to 1.9 (0.8–5.4) upon further restriction to before‐screening enrollees. RR of congenital malformations (n = 216) changed from 3.1 (1.4–8.5) to 3.2 (1.4–9.0) after conditioning on gestational week at enrollment and to 2.0 (0.7–10.1) upon further restriction to before‐screening enrollees. When comparing valproic acid users and lamotrigine users, the RR of congenital malformations was not substantially changed by conditioning or restricting.ConclusionsSpontaneous abortion rates were sensitive to gestational age at enrollment. Estimates of congenital malformation risks for AED users relative to non‐users were sensitive to before/after‐screening enrollment. This difference was not apparent between active drugs, likely due to similar gestational age at enrollment. Copyright © 2015 John Wiley & Sons, Ltd.
Balance and Gait in People with Multiple Sclerosis: A Comparison with Healthy Controls and the Immediate Change after an Intervention based on the Bobath Concept
Authors: Ilett P. , Lythgo N. , Martin C. , Brock K. 
Published: February 2015

AbstractBackground and purposeThe objective of this study is to compare the balance and gait of 11 people with multiple sclerosis (MS) to 11 healthy controls and to investigate the immediate change after a single intervention based on the Bobath concept on these activities in the MS group.MethodsBalance was assessed by ground reaction forces (GRF) and centre of pressure movements during single limb standing (SLS), the Lateral Reach Test (LRT) and the Four Square Step Test (FSST). Gait was evaluated by GRF, ankle kinematics and spatiotemporal measures.ResultsBaseline measures in the MS group showed significantly greater vertical GRF variability (p = 0.008) during SLS reached less distance on the LRT (p = 0.001) and were slower completing the FSST (p < 0.001). During gait, the MS group walked slower (p = 0.005) and had less ankle plantarflexion (PF) (p = 0.001) than the control group. Less peak vertical GRF (p < 0.001) and peak propulsive GRF (p = 0.004) at terminal stance and increased vertical GRF in midstance (p = 0.005) were observed. The measures of balance and gait were re‐assessed in the MS group immediately after a 20‐min intervention based on the Bobath concept delivered to the most impaired foot and ankle. After the intervention, the MS group had significant changes towards the control group values with reduced mediolateral (p = 0.002) and vertical (p = 0.016) GRF variability in the SLS task, faster FSST time (p = 0.006) and increased ankle PF during gait (p = 0.002).DiscussionThis study provides further evidence of balance and gait limitations in people with MS and indicates that a single treatment based on principles of the Bobath concept to the foot and ankle can result in immediate improvements in balance and ankle PF during gait in people with MS. Copyright © 2015 John Wiley & Sons, Ltd.