bluuebunny/crossref_metadata_2025 huggingface dataset:
Trend and periodicity of drought over Ethiopia
Authors: Zeleke T. T. , Giorgi F. , Diro G. T. , Zaitchik B. F.
Published: May 2017

We analyse rainfall extreme events in Ethiopia from 1979 to 2014 using the standardized precipitation index (SPI) and the Palmer drought severity index (PDSI) derived from both station and satellite‐based observation data sets. Causal mechanisms of extreme events are also discussed. Trend principal component (TPC), regression, wavelet and composite analyses are used to investigate the trend, frequency and inter/intra‐annual variability of extreme events (dryness/wetness of rainfall) over Ethiopia. All methods of analysis, applied to monthly mean data, show that the north and northwest regions of Ethiopia experienced frequent and more severe drought conditions centred at the year 1983/1984, a recovery in the middle of the study period and a return to moderate dry events in recent years. For the southern and southwestern regions, drought conditions have become more frequent and intense during the study period, particularly since ∼1997. Analysis at the seasonal scale shows that the observed drying trend over the south and southwestern regions of the country is dominated by the spring season, which corresponds to the season of maximum precipitation. No observed long‐term trend is found in the north, northwestern and central mountainous regions of the country. This contrast reflects differing climate sensitivities of these different portions of the country: the observed periodicity of dryness/wetness over the northern regions corresponds largely to ENSO variability in both the spring and summer rainy seasons, while the drying trend in the south and southwest is associated with Atlantic Ocean warming and sea surface temperature gradients across the western Pacific Ocean.
Relationship between the South China Sea summer monsoon onset and tropical cyclone genesis over the western North Pacific
Authors: Huangfu Jingliang , Huang Ronghui , Chen Wen
Published: May 2017

This study investigated the relationship between the onset date of the South China Sea summer monsoon (SCSSM) and tropical cyclone (TC) genesis over the western North Pacific (WNP). The inter‐annual WNP TC genesis numbers in May is significantly negatively correlated with the onset date of the SCSSM for the epoch of 1979–2015. In the early (late) onset SCSSM years, more (less) TCs tend to be generated. The monsoon trough would enter the WNP earlier in the early SCSSM years and its easternmost location would extend to the east of 140°E. This process would enhance the barotropic eddy energy conversions, which would convert more mean kinetic energy into eddy kinetic energy and supply more energy for TC genesis in the WNP in May. A predicted early (late) onset of the SCSSM might correlate with more WNP TC genesis in May.
Directing clinical care using lower extremity biomechanics in patients with ankle osteoarthritis and ankle arthroplasty
Authors: Queen Robin
Published: May 2017

Ankle osteoarthritis is a debilitating disease with approximately 50,000 new cases per year leading to skeletal deformity, severe and recurrent pain, cartilage breakdown, and gait dysfunction limiting patient mobility and well‐being. Although many treatments (total ankle arthroplasty [TAA], ankle fusion [arthrodesis], and ankle distraction arthroplasty) relieve pain, it is not clear that these procedures significantly improve patient mobility. The goal of the research presented here is to summarize what is presently known about lower extremity gait mechanics and outcomes and to quantify the impact of ankle osteoarthritis and TAA have on these measures using an explicitly holistic and mechanistic approach. Our recent studies have explored physical performance and energy recovery and revealed unexpected patterns and sequelae to treatment including incomplete restoration of gait function. These studies demonstrated for the first time the extreme levels and range of gait and balance dysfunction present in ankle osteoarthritis patients as well as quantifying the ways in which the affected joint alters movement and loading patterns not just in the painful joint, but throughout both the ipsilateral and contralateral lower extremity. Through this work, we determined that relieving pain alone through TAA is not enough to restore normal walking mechanics and balance due to underlying causes including limited ankle range of motion and balance deficits leading to long‐term disability despite treatment. The results indicate the need to consider additional therapeutic interventions aimed at restoring balance, ankle range of motion, and movement symmetry in order to improve long‐term health and function. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2345–2355, 2017.
Jaboticaba berry peel intake prevents insulin‐resistance‐induced tau phosphorylation in mice
Authors: Batista Ângela G. , Soares Edilene S. , Mendonça Monique C. P. , da Silva Juliana K. , Dionísio Ana Paula , Sartori Cesar R. , da Cruz‐Höfling Maria Alice , Maróstica Júnior Mário R.
Published: May 2017

The hyperphosphorylation of microtubule‐associated protein tau (tau) in the hippocampus can be caused by central and peripheral insulin resistance and these alterations are related to the development of tauopathies, such as Alzheimer's disease. In this study, we used a high‐fat diet to induce obesity and insulin resistance in adult Swiss mice and checked whether supplementation with Myrciaria jaboticaba berry peel for 10 weeks could improve insulin sensitivity, learning/memory performance, and prevent tau phosphorylation in the hippocampus. Furthermore, adipocytokines, inflammatory markers, and oxidative stress were assessed. Myrciaria jaboticaba peel has phenolic compounds (e.g., cyanidin, ellagic acid), dietary fiber and carotenoids, which contribute to great antioxidant capacity. Supplementation of the high‐fat diet with 4% M. jaboticaba peel prevented fat weight gain and reduced peripheral insulin resistance. The treated group also showed lower tau phosphorylation in the hippocampus corroborating better learning/memory performance in the Morris water maze test. Maintenance of neuronal viability, lower levels of hippocampal inflammatory markers, and improved brain antioxidant defenses were also related to the consumption of M. jaboticaba peel. These findings contribute to a better understanding of how a high‐fat diet supplemented with jaboticaba berry peel counteracts the impairment of cognitive functions caused by high‐fat diet intake and diet‐induced insulin resistance.
β‐Cryptoxanthin exerts greater cardioprotective effects on cardiac ischemia‐reperfusion injury than astaxanthin by attenuating mitochondrial dysfunction in mice
Authors: Pongkan Wanpitak , Takatori Osamu , Ni Yinhua , Xu Liang , Nagata Naoto , Chattipakorn Siriporn C. , Usui Soichiro , Kaneko Shuichi , Takamura Masayuki , Sugiura Minoru , Chattipakorn Nipon , Ota Tsuguhito
Published: May 2017

Scope

β‐Cryptoxanthin and astaxanthin are antioxidant carotenoid pigments that inhibit lipid peroxidation as potently as vitamin E. We hypothesized that acute treatment with β‐cryptoxanthin and astaxanthin causes similar reductions in the sizes of cardiac infarcts caused by ischemia‐reperfusion (I/R) injury by attenuating oxidative stress and cardiac mitochondrial dysfunction.

Methods and results

C57BL/6 mice (n = 36) were randomized to receive vehicle, β‐cryptoxanthin, astaxanthin, or vitamin E at 50 mg/kg by gavage feeding prior to I/R injury. Cardiac I/R was induced by left anterior descending coronary artery ligation followed by reperfusion. All treatments significantly reduced infarct sizes by 36–57%, attenuated apoptosis and also attenuated cardiac mitochondrial dysfunction in the treated groups compared to the control group. Although astaxanthin and vitamin E exhibited similar efficacy with respect to cardioprotection, β‐cryptoxanthin exhibited greater efficacy than its counterparts, as it reduced infarct sizes by 60%. β‐Cryptoxanthin was more effective than astaxanthin and vitamin E because it reduced cardiac mitochondrial swelling, mitochondrial depolarization, the Bax/Bcl‐2 ratio, and plasma and cardiac thiobarbituric acid reactive substances levels more significantly than its counterparts.

Conclusion

Acute β‐cryptoxanthin treatment exhibits greater cardioprotective efficacy against I/R injury than astaxanthin and vitamin E by reducing infarct sizes and attenuating apoptosis, oxidative stress, and mitochondrial dysfunction.
Experimental characterization of a direct conversion amorphous selenium detector with thicker conversion layer for dual‐energy contrast‐enhanced breast imaging
Authors: Scaduto David A. , Tousignant Olivier , Zhao Wei
Published: May 2017

Purpose

Dual‐energy contrast‐enhanced imaging is being investigated as a tool to identify and localize angiogenesis in the breast, a possible indicator of malignant tumors. This imaging technique requires that x‐ray images are acquired at energies above the k‐shell binding energy of an appropriate radiocontrast agent. Iodinated contrast agents are commonly used for vascular imaging, and require x‐ray energies greater than 33 keV. Conventional direct conversion amorphous selenium (a‐Se) flat‐panel imagers for digital mammography show suboptimal absorption efficiencies at these higher energies.

Methods

We use spatial‐frequency domain image quality metrics to evaluate the performance of a prototype direct conversion flat‐panel imager with a thicker a‐Se layer, specifically fabricated for dual‐energy contrast‐enhanced breast imaging. Imaging performance was evaluated in a prototype digital breast tomosynthesis (DBT) system. The spatial resolution, noise characteristics, detective quantum efficiency, and temporal performance of the detector were evaluated for dual‐energy imaging for both conventional full‐field digital mammography (FFDM) and DBT.

Results

The zero‐frequency detective quantum efficiency of the prototype detector is improved by approximately 20% over the conventional detector for higher energy beams required for imaging with iodinated contrast agents. The effect of oblique entry of x‐rays on spatial resolution does increase with increasing photoconductor thickness, specifically for the most oblique views of a DBT scan. Degradation of spatial resolution due to focal spot motion was also observed. Temporal performance was found to be comparable to conventional mammographic detectors.

Conclusions

Increasing the a‐Se thickness in direct conversion flat‐panel imagers results in better performance for dual‐energy contrast‐enhanced breast imaging. The reduction in spatial resolution due to oblique entry of x‐rays is appreciable in the most extreme clinically relevant cases, but may not profoundly affect reconstructed images due to the algorithms and filters employed. Degradation to projection domain spatial resolution is thus outweighed by the improvement in detective quantum efficiency for high‐energy x‐rays.
Simultaneous measurement of T1/B1 and pharmacokinetic model parameters using active contrast encoding (ACE)‐MRI
Authors: Zhang Jin , Winters Kerryanne , Reynaud Olivier , Kim Sungheon Gene
Published: May 2017

The aim of this study was to assess the feasibility of combining dynamic contrast enhanced‐magnetic resonance imaging (DCE‐MRI) with the measurement of the radiofrequency (RF) transmit field B1 and pre‐contrast longitudinal relaxation time T10. A novel approach has been proposed to simultaneously estimate B1 and T10 from a modified DCE‐MRI scan that actively encodes the washout phase of the curve with different amounts of T1 and B1 weighting using multiple flip angles and repetition times, hence referred to as active contrast encoding (ACE)‐MRI. ACE‐MRI aims to simultaneously measure B1 and T10, together with contrast kinetic parameters, such as the transfer constant Ktrans, interstitial space volume fraction ve and vascular space volume fraction vp. The proposed method was tested using numerical simulations and in vivo studies with mouse models of breast cancer implanted in the flank and mammary fat pad, and glioma in the brain. In the numerical simulation study with a signal‐to‐noise ratio of 10, both B1 and T10 were estimated accurately with errors of 5.1 ± 3.5% and 12.3 ± 8.8% and coefficients of variation (CV) of 14.9 ± 8.6% and 15.0 ± 5.0%, respectively. Using the same ACE‐MRI data, the kinetic parameters Ktrans, ve and vp were also estimated with errors of 14.2 ± 8.3% (CV = 13.5 ± 4.6%), 14.7 ± 9.9% (CV = 13.3 ± 4.5%) and 14.0 ± 9.3% (CV = 14.0 ± 4.5%), respectively. For the in vivo tumor data from 11 mice, voxel‐wise comparisons between ACE‐MRI and DCE‐MRI methods showed that the mean differences for the five parameters were as follows: ΔKtrans = 0.006 (/min), Δve = 0.016, Δvp = 0.000, ΔB1 = −0.014 and ΔT1 = −0.085 (s), which suggests a good agreement between the two methods. When compared with separately measured B1 and T10, and DCE‐MRI estimated kinetic parameters as a reference, the mean relative errors of ACE‐MRI estimation were B1 = −0.3%, T10 = −8.5%, Ktrans = 11.4%, ve = 14.5% and vp = 4.5%. This proof‐of‐concept study demonstrates that the proposed ACE‐MRI method can be used to estimate B1 and T10, together with contrast kinetic model parameters.
A dynamic variational multiscale method for viscoelasticity using linear tetrahedral elements
Authors: Zeng Xianyi , Scovazzi Guglielmo , Abboud Nabil , Colomés Oriol , Rossi Simone
Published: May 2017

In this article, we develop a dynamic version of the variational multiscale (D‐VMS) stabilization for nearly/fully incompressible solid dynamics simulations of viscoelastic materials. The constitutive models considered here are based on Prony series expansions, which are rather common in the practice of finite element simulations, especially in industrial/commercial applications. Our method is based on a mixed formulation, in which the momentum equation is complemented by a pressure equation in rate form. The unknown pressure, displacement, and velocity are approximated with piecewise linear, continuous finite element functions. To prevent spurious oscillations, the pressure equation is augmented with a stabilization operator specifically designed for viscoelastic problems, in that it depends on the viscoelastic dissipation. We demonstrate the robustness, stability, and accuracy properties of the proposed method with extensive numerical tests in the case of linear and finite deformations.
Effect of particle–particle and polymer–particle interactions on nanosilica aggregation in polystyrene
Authors: Sanjari Shahrezaei Mohamad Ali , Goharpey Fatemeh , Foudazi Reza
Published: May 2017

In this work, we show that the particle–particle interactions are more effective than polymer–particle interactions on the dispersion of both hydrophobic and hydrophilic nanosilica in polystyrene (PS) nanocomposites. The surface hydrophobization of nanoparticles weakens the particle‐particle interaction and prevents nanoparticle aggregation. Rheological measurements are employed to study the aggregation behavior of samples. A comparative faster stress relaxation modulus G(t) indicates the lower extent of aggregation and a weaker polymer particle network. Additionally, the structure of the particle network is studied by using the percolation and fractal models. The results demonstrate that particles with higher hydrophobicity form aggregates with lower fractal dimension and have higher percolation threshold. The amount of adhered polymer chain is affected by particle's surface chemistry. The contribution of adhered chains on the particles to the dynamic modulus is also studied theoretically. POLYM. COMPOS., 39:2904–2914, 2018. © 2017 Society of Plastics Engineers
Bond behavior of NiTiNb SMA wires embedded in CFRP composites
Authors: El‐Tahan M. , Dawood M.
Published: May 2017

This article summarizes the details of an experimental and analytical program that was conducted to study the bond behavior between nickel‐titanium‐niobium shape memory alloy wires and fiber reinforced polymer composites. Understanding this bond behavior will facilitate the design of composite systems that are fabricated using both materials and which would exhibit unique properties that cannot be achieved using either material separately. A total of nine pull‐out specimens were fabricated and tested. A digital image correlation (DIC) noncontact measurement system was used to identify the onset and propagation of the debonding. The experimental results indicated that the interfacial bond transfer consists of two components: cohesion (before the onset of debonding) and friction (after the onset of debonding). A 3‐D nonlinear finite element analysis (FEA) was conducted to investigate the debonding mechanism of the pull‐out specimens. A trilinear cohesive zone model was used to model the interface taking into account the cohesive and friction components of the stress transfer at the interface. The debonding mechanism predicted by the FEA matches the experimental observations that were obtained using conventional instruments and the DIC system, well. POLYM. COMPOS., 39:3780–3791, 2018. © 2017 Society of Plastics Engineers
The influence of irradiated recycled polypropylene compatibilizer on the impact fracture behavior of recycled polypropylene/microcrystalline cellulose composites
Authors: Lazim N. H. , Samat N.
Published: May 2017

The poor compatibility between a thermoplastic matrix and natural fiber reinforcement has been a limitation in the optimization of natural fiber‐filled composites. Electron beam irradiation is used to modify the structure of materials. However, most researches have focused on the effect of irradiation after the fabrication of composites. Hence, this study was aimed at investigating the effect of irradiated recycled polypropylene (i‐rPP) as a compatibilizer in recycled polypropylene (rPP) composites. The rPP were irradiated at different doses before the compounding process. The rPP matrices were prepared by mixing the unirradiated and irradiated rPP at ratios of 90:10 and 50:50, before they were compounded with different amounts of microcrystalline cellulose (MCC) fibers (5, 20, and 40 wt%). Radiation crosslinking, functional groups, radical formations, thermal, and impact strength characterizations were carried out. The results showed that the simultaneous incorporation of the i‐rPP and MCC fibers significantly improved the impact resistance of the rPP. The synergistic combination of a higher MCC content (40 wt%) and low irradiation dose (10 kGy) at a ratio of 50:50 caused a higher degree of crosslinking and a lower radical concentration. The thermal stability was acceptable and the sub‐impact fracture surface analysis revealed the effects of crack blunting. POLYM. COMPOS., 40:E24–E34, 2019. © 2017 Society of Plastics Engineers
Assessing the prevalence of dexamethasone use in patients undergoing surgery, and subsequent glucose measurements: a retrospective cohort study
Authors: Sudlow Alexis , O'Connor Henry M , Narwani Vishal , Swafe Leyla , Dhatariya Ketan
Published: May 2017

A single dose of glucocorticoid can cause hyperglycaemia. Hyperglycaemia is associated with poor outcomes in all surgical specialties. Dexamethasone is widely used to prevent postoperative nausea and vomiting. We aimed to assess how many individuals were given dexamethasone as part of their general anaesthetic regimen, and how many had a subsequent capillary blood glucose concentration measured during the next 24 hours.

We undertook a retrospective case‐note analysis, set in a single centre teaching hospital, of all patients undergoing surgery during one week in August 2013. In terms of interventions and measurements, we assessed how many patients were given dexamethasone perioperatively and the number of patients who had a capillary blood glucose concentration measured during the subsequent 24 hours.

It was found that 373 patients had had a general anaesthetic; 18 sets of case notes were unavailable. A total of 234 patients (66%) had dexamethasone. Twenty of the 355 (5.7%) had a blood glucose measured prior to surgery, 14 of whom had diabetes. Only 16/355 (4.5%) people had a blood glucose level measured during the first 24 hours after surgery. All of these had diabetes.

Despite evidence that postoperative hyperglycaemia is associated with harm, and that glucocorticoids are associated with hyperglycaemia, glucose levels are not commonly measured after dexamethasone administration. Copyright © 2017 John Wiley & Sons.
Production of doxycycline‐loaded gelatin microspheres through thermal treatment in inverse suspensions
Authors: Way Débora Vieira , Nele Márcio , Pinto José Carlos
Published: May 2017

Doxycycline is a broad‐spectrum antibiotic. The development of a polymer matrix that can allow for the controlled release of this drug can bring many benefits to veterinary and human medicine. For this reason, in the present study doxycycline was encapsulated in situ with gelatin through thermal treatments performed in inverse suspension, using distinct gelatin concentrations in the suspended aqueous phase. To characterize the performances of the obtained products, controlled release tests were performed. The effect of adding formaldehyde and glucose into the reaction medium to enhance gelatin crosslinking was analyzed, although obtained results indicated that addition of crosslinking agents is not necessary because addition of doxycycline is sufficient to promote the physical gelatin crosslinking. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers
Suicide attempts and self‐injurious behaviours in adolescent and adult patients with borderline personality disorder
Authors: Goodman Marianne , Tomas Irene Alvarez , Temes Christina M. , Fitzmaurice Garrett M. , Aguirre Blaise A. , Zanarini Mary C.
Published: May 2017

Objective

Prevalence data on self‐mutilation and suicide attempts for adolescent borderline personality disorder (BPD) are currently not available. The purpose of this paper was to determine the frequency and methods of two forms of physically self‐destructive acts (i.e. self‐mutilation and suicide attempts) reported by adolescent borderline inpatients in one of the largest samples to date and to compare these results with a similarly diagnosed and assessed group of adult borderline inpatients.

Methods

A total of 104 adolescent inpatients with BPD and 290 adult inpatients with BPD were interviewed about their lifetime history of physically self‐destructive acts.

Results

The overall rates of self‐mutilation (about 90%) and suicide attempts (about 75%) were similar during index admission for both adolescent and adult borderline patients. However, adolescents reported significantly higher rates of extreme levels of lifetime self‐mutilation (e.g. >25 and >50 episodes) and cutting in particular, as compared with adult BPD. In contrast, borderline adults were significantly more likely to report a history of numerous (five or more) suicide attempts than adolescents with BPD.

Conclusions

Self‐mutilation and suicide attempts among adolescent borderline patients are prevalent and serious. Taken together, these results suggest that extreme levels of self‐mutilation distinguish adolescent BPD from adults with BPD. Copyright © 2017 John Wiley & Sons, Ltd.
A rapid expression and purification condition screening protocol for membrane protein structural biology
Authors: Sjöstrand Dan , Diamanti Riccardo , Lundgren Camilla A. K. , Wiseman Benjamin , Högbom Martin
Published: May 2017

Membrane proteins control a large number of vital biological processes and are often medically important—not least as drug targets. However, membrane proteins are generally more difficult to work with than their globular counterparts, and as a consequence comparatively few high‐resolution structures are available. In any membrane protein structure project, a lot of effort is usually spent on obtaining a pure and stable protein preparation. The process commonly involves the expression of several constructs and homologs, followed by extraction in various detergents. This is normally a time‐consuming and highly iterative process since only one or a few conditions can be tested at a time. In this article, we describe a rapid screening protocol in a 96‐well format that largely mimics standard membrane protein purification procedures, but eliminates the ultracentrifugation and membrane preparation steps. Moreover, we show that the results are robustly translatable to large‐scale production of detergent‐solubilized protein for structural studies. We have applied this protocol to 60 proteins from an E. coli membrane protein library, in order to find the optimal expression, solubilization and purification conditions for each protein. With guidance from the obtained screening data, we have also performed successful large‐scale purifications of several of the proteins. The protocol provides a rapid, low cost solution to one of the major bottlenecks in structural biology, making membrane protein structures attainable even for the small laboratory.
Experimental charge density from electron microscopic maps
Authors: Wang Jimin
Published: May 2017

The charge density (CD) distribution of an atom is the difference per unit volume between the positive charge of its nucleus and the distribution of the negative charges carried by the electrons that are associated with it. The CDs of the atoms in macromolecules are responsible for their electrostatic potential (ESP) distributions, which can now be visualized using cryo‐electron microscopy at high resolution. CD maps can be recovered from experimental ESP density maps using the negative Laplacian operation. CD maps are easier to interpret than ESP maps because they are less sensitive to long‐range electrostatic effects. An ESP‐to‐CD conversion involves multiplication of amplitudes of structure factors as Fourier transforms of these maps in reciprocal space by 1/d2, wheredis the resolution of reflections. In principle, it should be possible to determine the charges carried by the individual atoms in macromolecules by comparing experimental CD maps with experimental ESP maps.
Korean Red Ginseng Extract Enhances the Anticancer Effects of Sorafenib through Abrogation of CREB and c‐Jun Activation in Renal Cell Carcinoma
Authors: Kim Chulwon , Lee Jong Hyun , Baek Seung Ho , Ko Jeong‐Hyeon , Nam Dongwoo , Ahn Kwang Seok
Published: May 2017

Although application of sorafenib in the treatment of human renal cell carcinoma (RCC) remains one of the best examples of successful targeted therapy, majority of RCC patients suffer from its side effects as well as develop resistance to this targeted therapy. Thus, there is a need to promote novel alternative therapies for the treatment of RCC. In this study, we investigated whether Korean red ginseng extract (KRGE) could inhibit the proliferation and induce chemosensitization in human renal cancer cells. Also, we used a human phospho‐antibody array containing 46 antibodies against signaling molecules to examine a subset of phosphorylation events after KRGE and sorafenib combination treatment. Korean red ginseng extract suppressed the proliferation of two RCC cell lines; activated caspase‐3; caused poly(ADP‐ribose) polymerase cleavage; abrogated the expression of B‐cell lymphoma 2, B‐cell lymphoma extra large, survivin, inhibitors of apoptosis proteins‐1/2, cyclooxygenase‐2, cyclin D1, matrix metallopeptidase‐9, and vascular endothelial growth factor; and upregulated pro‐apoptotic gene products. Interestingly, KRGE enhanced the cytotoxic and apoptotic effects of sorafenib in RCC cells. The combination treatment of KRGE and sorafenib more clearly suppressed cyclic adenosine monophosphate response element‐binding protein and c‐Jun phosphorylation and induced phosphorylation of p53 than did the individual treatment regimen. Our results clearly demonstrate that KRGE can enhance the anticancer activity of sorafenib and may have a substantial potential in the treatment of RCC. Copyright © 2017 John Wiley & Sons, Ltd.
Introducing independent patterns into the Stochastically Perturbed Parametrization Tendencies (SPPT) scheme
Authors: Christensen H. M. , Lock S.‐J. , Moroz I. M. , Palmer T. N.
Published: May 2017

The Stochastically Perturbed Parametrization Tendencies (SPPT) scheme is used at weather and climate forecasting centres worldwide to represent model uncertainty that arises from simplifications involved in the parametrization process. It uses spatio‐temporally correlated multiplicative noise to perturb the sum of the parametrized tendencies. However, SPPT does not distinguish between different parametrization schemes, which do not necessarily have the same error characteristics. A generalization to SPPT is proposed, whereby the tendency from each parametrization scheme can be perturbed using an independent stochastic pattern. This acknowledges that the forecast errors arising from different parametrizations are not perfectly correlated. Two variations of this ‘independent SPPT’ (iSPPT) approach are tested in the Integrated Forecasting System (IFS). The first perturbs all parametrized tendencies independently, while the second groups tendencies before perturbation. The iSPPT schemes lead to statistically significant improvements in forecast reliability in the Tropics in medium‐range weather forecasts. This improvement can be attributed to a large, beneficial increase in ensemble spread in regions with significant convective activity. The iSPPT schemes also lead to improved forecast skill in the extratropics for a set of cases in which the synoptic initial conditions were more likely to result in European ‘forecast busts’. Longer 13 month simulations are also considered to indicate the effect of iSPPT on the mean climate of the IFS.
A note on apparent solar time and the seasonal cycle of atmospheric solar tides
Authors: Hamilton Kevin , Sakazaki Takatoshi
Published: May 2017

Both observations and comprehensive model simulation data of atmospheric fields are generally available at fixed Mean Solar Times through the day, which is convenient as the notional ‘mean sun’ progresses around the Earth each day in exactly 24 h. This article reports on a simple investigation of the effect of correcting data taken in Mean Solar Time to account for the difference in position between the actual (or ‘apparent’) sun and the mean sun, with a focus on characterizing atmospheric tidal oscillations. In particular, we found that the annual cycle in the phase of the semidiurnal atmospheric tidal oscillation of surface pressure near the Equator is almost entirely explained by the difference between Mean Solar Time and Apparent Solar Time. This result was confirmed in raw barometric observations as well as in several global reanalysis datasets.
Role of large eddies in the breakdown of the Reynolds analogy in an idealized mildly unstable atmospheric surface layer
Authors: McColl Kaighin A. , van Heerwaarden Chiel C. , Katul Gabriel G. , Gentine Pierre , Entekhabi Dara
Published: May 2017

While the breakdown in similarity between turbulent transport of heat and momentum (or Reynolds analogy) is not disputed in the atmospheric surface layer (ASL) under unstably stratified conditions, the causes of this breakdown are still debated. One reason for the breakdown is differences between how coherent structures transport heat and momentum, and their differing responses to increasing instability. Monin—Obukhov Similarity Theory (MOST), which hypothesizes that only local length‐scales play a role in ASL turbulent transport, implicitly assumes that large‐scale structures are inactive, despite their large energy content. Widely adopted mixing‐length models also rest on this assumption in the ASL. The difficulty of characterizing low‐wavenumber turbulent motions with field measurements motivates the use of high‐resolution Direct Numerical Simulation (DNS), which is free from subgrid‐scale parametrizations and adhoc assumptions near the boundary. Despite the low Reynolds number and idealized geometry of the DNS, DNS‐estimated MOST functions are consistent with ASL field experiments, as are low‐frequency features of the spectra. Parsimonious spectral models for MO stability correction functions for momentum (φm) and heat (φh) are derived, based on idealized vertical velocity variance and buoyancy variance spectra fit to the corresponding DNS spectra. For φm, a spectral model, based only on local length‐scales, matches DNS and field measurements well. In contrast, for φh, the model is substantially biased unless contributions from larger length‐scales are also included. These results are supported by sensitivity analyses based on field measurements that are independent of the DNS. They show that ASL heat transport is not MO‐similar, even under mild stratification, and in the absence of entrainment, non‐stationarity and canopy effects. It further suggests that the breakdown of the Reynolds analogy is at least partially caused by the influence of large eddies on turbulent heat transport.
Hollow Mesoporous Carbon Microparticles and Micromotors with Single Holes Templated by Colloidal Silica‐Assisted Gas Bubbles
Authors: Huang Xiaoxi , Zhang Tao , Asefa Tewodros
Published: May 2017

A simple, new synthetic method that produces hollow, mesoporous carbon microparticles, each with a single hole on its surface, is reported. The synthesis involves unique templates, which are composed of gaseous bubbles and colloidal silica, and poly(furfuryl alcohol) as a carbon precursor. The conditions that give these morphologically unique carbon microparticles are investigated, and the mechanisms that result in their unique structures are proposed. Notably, the amount of colloidal silica and the type of polymer are found to hugely dictate whether or not the synthesis results in hollow asymmetrical microparticles, each with a single hole. The potential application of the particles as self‐propelled micromotors is demonstrated.
Albumin‐Templated Manganese Dioxide Nanoparticles for Enhanced Radioisotope Therapy
Authors: Tian Longlong , Chen Qian , Yi Xuan , Chen Jiawen , Liang Chao , Chao Yu , Yang Kai , Liu Zhuang
Published: May 2017

Although nanoparticle‐based drug delivery systems have been widely explored for tumor‐targeted delivery of radioisotope therapy (RIT), the hypoxia zones of tumors on one hand can hardly be reached by nanoparticles with relatively large sizes due to their limited intratumoral diffusion ability, on the other hand often exhibit hypoxia‐associated resistance to radiation‐induced cell damage. To improve RIT treatment of solid tumors, herein, radionuclide 131I labeled human serum albumin (HSA)‐bound manganese dioxide nanoparticles (131I‐HSA‐MnO2) are developed as a novel RIT nanomedicine platform that is responsive to the tumor microenvironment (TME). Such 131I‐HSA‐MnO2 nanoparticles with suitable sizes during blood circulation show rather efficient tumor passive uptake owing to the enhanced permeability and retention effect, as well as little retention in other normal organs to minimize radiotoxicity. The acidic TME can trigger gradual degradation of MnO2 and thus decomposition of 131I‐HSA‐MnO2 nanoparticles into individual 131I‐HSA with sub‐10 nm sizes and greatly improves intratumoral diffusion. Furthermore, oxygen produced by MnO2‐triggered decomposition of tumor endogenous H2O2 would be helpful to relieve hypoxia‐associated RIT resistant for those tumors. As the results, the 131I‐HSA‐MnO2 nanoparticles appear to be a highly effective RIT agent showing great efficacy in tumor treatment upon systemic administration.
A new cynodont from the Santa Maria formation, south Brazil, improves Late Triassic probainognathian diversity
Authors: Martinelli Agustín G. , Eltink Estevan , Da‐Rosa Átila A. S. , Langer Max C.
Published: May 2017

The fossil record of non‐mammaliaform probainognathian cynodonts is outstanding in the Late Triassic rocks of Brazil and Argentina. Approximately 15 genera are known, providing unique insights in the study of the major skeletal transformations prior to the mammalian condition. Globally, the diversity of probainognathians is possibly under‐represented, as the discovery of small‐ to very small‐sized taxa based on relatively well‐preserved specimens is rare. Several species, for example much of the Laurasian record, are based on isolated teeth and jaw fragments. Here, we describe a new probainognathian from the Late Carnian Hyperodapedon Assemblage Zone of the Santa Maria Formation, south Brazil. Alemoatherium huebneri gen. et sp. nov. is based on a left lower jaw with almost complete dentition that exhibits a combination of features not seen in any other known probainognathian. Its slender lower jaw, anterodorsally bent process of the dentary, high number of lower incisors, reduced canine, triconodont‐like postcanine teeth with mesiolingual and distolingual cingular cusps are all features that support the inclusion of A. huebneri as a member of the Prozostrodontia clade. This new find highlights the conspicuous probainognathian cynodont fossil record in southern Brazil, with a plethora of forms near the mammalian origin.
Improved technical success, postnatal outcome and refined predictors of outcome for fetal aortic valvuloplasty
Authors: Friedman K. G. , Sleeper L. A. , Freud L. R. , Marshall A. C. , Godfrey M. E. , Drogosz M. , Lafranchi T. , Benson C. B. , Wilkins‐Haug L. E. , Tworetzky W.
Published: May 2017

Objectives

Fetal aortic valvuloplasty (FAV) may prevent progression of mid‐gestation aortic stenosis to hypoplastic left heart syndrome (HLHS). The aim of this study was to evaluate whether technical success and biventricular (Biv) outcome after FAV have changed from an earlier (2000–2008) to a more recent (2009–2015) era and identify pre‐FAV predictors of Biv outcome.

Methods

We evaluated procedural and postnatal outcomes in 123 fetuses that underwent FAV for evolving HLHS at Boston Children's Hospital between 2000 and 2015. The primary outcome measure was circulation type (Biv vs single ventricle) at the time of neonatal hospital discharge. Classification and regression tree (CART) analysis was performed to construct a stratification algorithm to predict Biv circulation based on pre‐FAV fetal variables.

Results

The FAV procedure was technically successful in 101/123 (82%) fetuses, with a higher technical success rate in the more recent era than in the earlier one (49/52 (94%) vs 52/71 (73%); P = 0.003). In liveborn patients, the incidence of Biv outcome was higher in the recent than in the earlier era, both in the entire liveborn cohort (29/49 (59%) vs 16/62 (26%); P = 0.001) and in those in whom the procedure was technically successful (27/46 (59%) vs 15/47 (32%); P = 0.007). Independent predictors of Biv outcome were higher left ventricular (LV) pressure, larger ascending aorta, better LV diastolic function and higher LV long‐axis Z‐score. On CART analysis, fetuses with LV pressure > 47 mmHg and ascending aorta Z‐score ≥ 0.57 had a 92% probability of Biv outcome (n = 24). Those with a lower LV pressure, or mitral dimension Z‐score < 0.1 and mitral valve inflow time Z‐score < –2 (n = 34) were unlikely to have Biv (probability of 9%). The remainder of the patients had an intermediate (∼40–60%) likelihood of Biv circulation.

Conclusions

The proportion of patients achieving Biv outcome after FAV has increased, probably owing to an improved technical success rate and modified selection criteria. Fetal factors, including LV pressure, size of the ascending aorta and diastolic function, are associated with likelihood of Biv circulation after FAV. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.
Contributions and perspectives from geography to the study of climate
Authors: Randalls Samuel
Published: May 2017

Geographers have played an important and sometimes controversial role in the study of climate during the 20th century. This review traces the historical contributions of geographical scholarship to the study of climate in two primary areas: statistical, descriptive climatology and research in climate and society. It draws out the specifically geographical nature of climatological work in the 20th century, looking at the role of maps, classifications, and historical statistics in describing and potentially explaining climatic cycles, patterns, and processes. Geographers were keen to demonstrate the broader linkages between climate and the physical environment and humankind, such that applications of climatological expertise were crucial to economic development, imperialism and local scales, particularly the urban scale. This led geographers into insightful interdisciplinary applications, but also rather more awkward themes such as climatic determinism. The review draws out both the positive and negative aspects of geography's contribution to understandings of climate. WIREs Clim Change 2017, 8:e466. doi: 10.1002/wcc.466

This article is categorized under:

Climate, History, Society, Culture > Disciplinary Perspectives
The influence of time since introduction on the population growth of introduced species and the consequences for management
Authors: Yokomizo Hiroyuki , Takada Takenori , Fukaya Keiichi , Lambrinos John G.
Published: May 2017

Several processes likely act to change the demographic rates of introduced species over time, and this changing demography could influence the optimal management of invasive populations. Optimal management strategies should be derived based on the demography. However, we have a poor understanding of the degree to which the demography of introduced species changes following initial introduction. We used published matrix population models of introduced plant populations to test how population growth rate and elasticity change with time since introduction. We did not find a significant relationship between population growth rate and time since introduction. However, elasticity to stasis increased while elasticity to growth decreased with time since introduction. Broadly, as time since introduction progressed the elasticities of the introduced plant populations became more similar to those that have been reported for native species. These results suggest that the optimal management strategy should be derived incorporating elasticity through time, especially when the time scope of management is long or the available demographic data were obtained in the past.
Fed-batch hydrolysate addition and cell separation by settling in high cell density lignocellulosic ethanol fermentations on AFEX™ corn stover in the Rapid Bioconversion with Integrated recycling Technology process
Authors: Sarks Cory , Jin Mingjie , Balan Venkatesh , Dale Bruce E
Published: May 2017

The Rapid Bioconversion with Integrated recycling Technology (RaBIT) process uses enzyme and yeast recycling to improve cellulosic ethanol production economics. The previous versions of the RaBIT process exhibited decreased xylose consumption using cell recycle for a variety of different micro-organisms. Process changes were tested in an attempt to eliminate the xylose consumption decrease. Three different RaBIT process changes were evaluated in this work including (1) shortening the fermentation time, (2) fed-batch hydrolysate addition, and (3) selective cell recycling using a settling method. Shorting the RaBIT fermentation process to 11 h and introducing fed-batch hydrolysate addition eliminated any xylose consumption decrease over ten fermentation cycles; otherwise, decreased xylose consumption was apparent by the third cell recycle event. However, partial removal of yeast cells during recycle was not economical when compared to recycling all yeast cells.
Parental Perspectives on Pharmacological Clinical Trials: a Qualitative Study in Down Syndrome and Fragile X Syndrome
Authors: Reines Victoria , Charen Krista , Rosser Tracie , Eisen Arri , Sherman Stephanie L. , Visootsak Jeannie
Published: May 2017

Research studies focusing on parents’ perspectives of pharmacological clinical trials have not kept pace with the number of emerging pharmacologic clinical trials in Down syndrome (DS) and Fragile X syndrome (FXS). Since individuals with DS or FXS have limited cognitive ability to make decisions about their participation in clinical trials, it is important to consider the parents’ perspectives and explore the ways in which decisions are made for their children. Using a semi‐structured interview, we enrolled 9 parents of a child(ren) with FXS and 15 with a child with DS to analyze their views, experiences, and knowledge of pharmacological clinical trials. Although our study is preliminary in nature, it revealed that parents are generally supportive of pharmacological clinical trials, yet there may be concerns about safety and long‐term implications and consideration for their child in the decision process. There is also parental misunderstanding of the objectives of pharmacological clinical trials; thus, it is important for pharmaceutical companies, study investigators, clinicians/medical professionals, and parent advocacy groups to collaborate to provide appropriate and up‐to‐date educational resources that fully explain the risks and benefits of clinical trials.
Regularized Generalized Canonical Correlation Analysis: A Framework for Sequential Multiblock Component Methods
Authors: Tenenhaus Michel , Tenenhaus Arthur , Groenen Patrick J. F.
Published: May 2017

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