bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffusion MRI monitoring of specific structures in the irradiated rat brain
Authors: Constanzo Julie , Dumont Matthieu , Lebel Réjean , Tremblay Luc , Whittingstall Kevin , Masson‐Côté Laurence , Geha Sameh , Sarret Philippe , Lepage Martin , Paquette Benoit , Descoteaux Maxime
Published: February 2018

Purpose

The analysis of biological and mesoscopic structures properties by diffusion MRI (dMRI) in brain after radiation therapy remains challenging. In our study, we described the consequences associated with an unwanted dose to healthy tissue, assessing radiation‐induced brain alterations of living rats with dMRI compared to histopathology and behavioral assays.

Methods

The right primary motor cortex M1 of the rat brain was targeted by stereotactic radiosurgery with a mean radiation dose of 41 Gy. Multidirectional single b‐value dMRI data of the whole brain were acquired with a 7T small‐animal scanner before irradiation until 110 days post‐irradiation. Diffusion tensor imaging metrics, such as fractional anisotropy (FA), mean diffusivity (MD), axial (AD), and radial diffusivity (RD) were compared to brain alterations detected by immunohistochemistry and motor performances measured by a behavioral test.

Results

Between days 90 and 110, radiation necrosis was observed into the white matter spreading into M1. Results showed a reduction of FA in the corpus callosum and in the striatum, which was driven by an increase in RD from 90 to 110 days post‐irradiation, whereas only RD increased in M1. Values of RD and AD increased in the irradiated hippocampus, while FA remained constant. Moreover, an increased MD, AD and RD was observed in the hippocampus that was probably related to inflammation as well as reactive astrogliosis after 110 days post‐irradiation. Finally, rats did not exhibit locomotor deficits.

Conclusions

dMRI metrics can assess brain damage; the sensitivity of dMRI metrics depends on the brain region.
Simultaneous multislice refocusing via time optimal control
Authors: Rund Armin , Aigner Christoph Stefan , Kunisch Karl , Stollberger Rudolf
Published: February 2018

Purpose

Joint design of minimum duration RF pulses and slice‐selective gradient shapes for MRI via time optimal control with strict physical constraints, and its application to simultaneous multislice imaging.

Theory and Methods

The minimization of the pulse duration is cast as a time optimal control problem with inequality constraints describing the refocusing quality and physical constraints. It is solved with a bilevel method, where the pulse length is minimized in the upper level, and the constraints are satisfied in the lower level. To address the inherent nonconvexity of the optimization problem, the upper level is enhanced with new heuristics for finding a near global optimizer based on a second optimization problem.

Results

A large set of optimized examples shows an average temporal reduction of 87.1% for double diffusion and 74% for turbo spin echo pulses compared to power independent number of slices pulses. The optimized results are validated on a 3T scanner with phantom measurements.

Conclusion

The presented design method computes minimum duration RF pulse and slice‐selective gradient shapes subject to physical constraints. The shorter pulse duration can be used to decrease the effective echo time in existing echo‐planar imaging or echo spacing in turbo spin echo sequences.
An 8/15‐channel Tx/Rx head neck RF coil combination with region‐specific B1+ shimming for whole‐brain MRI focused on the cerebellum at 7T
Authors: Pfaffenrot Viktor , Brunheim Sascha , Rietsch Stefan H. G. , Koopmans Peter J. , Ernst Thomas M. , Kraff Oliver , Orzada Stephan , Quick Harald H.
Published: February 2018

Purpose

To design and evaluate an 8/15‐channel transmit/receive (Tx/Rx) head‐neck RF coil combination with region‐specific
shimming for whole‐brain MRI with focus on improved functional MRI of the cerebellum at 7 T.

Methods

An 8‐channel transceiver RF head coil was combined with a 7‐channel receive‐only array. The noise parameters and acceleration capabilities of this 8Tx/15Rx coil setup were compared with a commercially available 1Tx/32Rx RF head coil. Region‐specific 8‐channel
shimming was applied when using the 8Tx/15Rx RF coil. To evaluate the capability for functional MRI of the cerebellum, temporal SNR and statistical nonparametric maps for finger‐tapping experiments with 14 healthy subjects were derived by applying a variable slice thickness gradient‐echo echo‐planar functional MRI sequence.

Results

The 8Tx/15Rx setup had a lower maximum noise correlation between channels, but higher average correlations compared with the 1Tx/32Rx coil. Both RF coils exhibited identical g‐factors in the cerebellum with R = 3 acceleration. The enlarged FOV of the 8Tx/15Rx coil in combination with region‐specific
shimming increased homogeneity of the transmission field and temporal SNR in caudal cerebellar regions. Temporal SNR losses in cranial parts were reduced, resulting in more highly significant voxels in the caudally activated areas and identical patterns in the cranial cerebellar parts during a finger‐tapping task.

Conclusion

Compared with the 1Tx/32Rx RF coil, the presented 8Tx/15Rx RF coil combination successfully improves functional MRI of the human cerebellum at 7 T while maintaining whole‐brain coverage. A clear temporal SNR gain in caudal cerebellar regions is shown.
Simultaneous multislice acquisition without trajectory modification for hyperpolarized 13C experiments
Authors: Lau Angus Z. , Lau Justin Y. C. , Chen Albert P. , Cunningham Charles H.
Published: February 2018

Purpose

To investigate the feasibility of performing large FOV hyperpolarized 13C metabolic imaging using simultaneous multislice excitation.

Methods

A spectral‐spatial multislice excitation pulse was constructed by cosine modulation and incorporated into a 13C spiral imaging sequence. Phantom and in vivo pig experiments were performed to test the feasibility of simultaneous multislice data acquisition and image reconstruction. In vivo cardiac‐gated images of hyperpolarized pyruvate, bicarbonate, and lactate were obtained at 1 × 1 × 1 cm3 resolution over a 48 × 48 × 24 cm3 FOV with 2‐fold acceleration in the slice direction. Sensitivity encoding was used for image reconstruction with both autocalibrated and numerically calculated coil sensitivities.

Results

Simultaneous multislice images obtained with 2‐fold acceleration were comparable to reference unaccelerated images. Retained SNR figures greater than 80% were achieved over the part of the image containing the heart.

Conclusion

This method is anticipated to enable large FOV imaging studies using hyperpolarized 13C substrates, with an aim toward whole‐body exams that have to date been out of reach.
Demographic features of female urethra length
Authors: Pomian Andrzej , Majkusiak Wojciech , Kociszewski Jacek , Tomasik Paweł , Horosz Edyta , Zwierzchowska Aneta , Lisik Wojciech , Barcz Ewa
Published: February 2018

Aims

To determine cohort urethral length, identify epidemiological factors influencing the parameter and to establish the percentage of cases with clinically relevant outsized urethras.

Methods

Prospective cohort study conducted in two tertiary clinical centers between 2013 and 2017. Nine hundred and twenty seven consecutive adult, Caucasian females attending outpatients’ clinics were included. The urethral length has been measured in pelvic floor ultrasound examination. The exclusion criteria were inadequate bladder filling (<200 mL; >400 mL), previous history of pelvic floor surgery, and no consent.

Results

Urethral length varied from 19 to 45 mm. The distribution of the examined parameter was normal. Obese patients had significantly longer urethras as compared to non‐obese subjects. Number of vaginal deliveries was connected with shorter urethral length. The limitations of the study are: analysis only of Caucasian patients and subjects without previous pelvic floor surgeries.

Conclusions

Differences in urethral length in the female population were demonstrated. Thirty percent of patients have atypical urethras that may be a risk factor for sling surgery failure. We therefore postulate introduction of urethral measurement before the procedure.
The role of the mucosa in modulation of evoked responses in the spinal cord injured rat bladder
Authors: Doyle Claire , Cristofaro Vivian , Sack Bryan S. , Mahmood Fabliha , Sullivan Maryrose P. , Adam Rosalyn M.
Published: February 2018

Aims

Mounting evidence indicates that a variety of factors released from the urothelium or suburothelium can modulate smooth muscle activity. Although the relationship between the mucosa and smooth muscle has been investigated, little is known about the pathophysiologic changes in detrusor‐mucosa interactions in neurogenic bladders. The goal of the study was to determine the impact of the mucosa on evoked responses in spinal cord injured (SCI) bladders.

Methods

Urinary bladders were obtained from 6wk SCI rats or age‐matched uninjured controls. Ex vivo isometric tension studies were performed and muscarinic receptor expression was measured in bladder tissue with and without mucosa.

Results

The magnitude and area of nerve evoked responses in SCI tissue with mucosa was higher than without mucosa. The duration and decay time of nerve‐evoked responses were longer in SCI than control tissue irrespective of the mucosa. The level of the muscarinic M2 receptor was decreased in the mucosa of SCI bladders.

Conclusions

Detrusor‐mucosa interactions are substantially altered in the neurogenic bladder. After spinal cord injury, an excitatory modulation of smooth muscle contraction by the mucosa emerges, and could be targeted via intravesical treatment in the context of neurogenic bladder dysfunction.
Weight Stigma Predicts Poorer Psychological Well‐Being Through Internalized Weight Bias and Maladaptive Coping Responses
Authors: Hayward Lydia E. , Vartanian Lenny R. , Pinkus Rebecca T.
Published: February 2018

Objective

Weight‐based stigmatization is associated with negative psychological and behavioral consequences, but individuals respond to stigma in different ways. The present study aimed to understand some of the factors that predict how one will cope with weight stigma and how different coping responses predict psychological well‐being.

Methods

Across four samples, 1,391 individuals who identified as having overweight or obesity completed surveys assessing the frequency of weight stigma experiences, internalized weight bias, coping responses to weight stigma, and psychological distress.

Results

Frequency of weight stigma predicted greater internalized weight bias, which predicted more frequent use of maladaptive coping responses (“disengagement coping”) and less frequent use of adaptive coping responses (“reappraisal coping”), in turn predicting more depression, anxiety, and stress symptoms.

Conclusions

The more that individuals with overweight or obesity experience weight stigma and internalize weight bias, the more they report using maladaptive coping and the less they report using adaptive coping when dealing with weight stigma. Maladaptive coping is strongly associated with poorer psychological well‐being. Thus, those who experience more frequent weight stigma may be more vulnerable to psychological distress because they appear to be at greater risk of employing maladaptive coping strategies.
Longitudinal Increases in Adiposity Contribute to Worsening Adipokine Profile over Time in Mexican Americans
Authors: Black Mary Helen , Shu Yu‐Hsiang , Wu Jun , Koebnick Corinna , MacKay Adrienne , Watanabe Richard M. , Buchanan Thomas A. , Xiang Anny H.
Published: February 2018

Objective

Limited studies have assessed the relationship between longitudinal changes in adiposity and changes in multiple adipokines over time. This study examined changes in BMI, total body fat, and trunk fat associated with changes in 16 circulating adipokines in Mexican Americans at risk for type 2 diabetes.

Methods

Participants included 1,213 individuals with cross‐sectional data and a subset of 368 individuals with follow‐up measures (mean 4.6 ± 1.5 years from baseline). Joint multivariate associations between 3 adiposity measures and 16 adipokines were assessed by canonical correlation analysis.

Results

Longitudinal increases in adiposity were most strongly associated with increasing leptin, C‐reactive protein (CRP), and interleukin 1 receptor antagonist (IL‐1Ra) and decreasing adiponectin and secreted frizzled protein 5 (SFRP5) over time. Participants with BMI ≥ 30 kg/m2 at baseline had greater increases in leptin, CRP, IL‐1Ra, and interleukin 6 (IL‐6) and greater decreases in adiponectin and SFRP5, associated with increasing adiposity over follow‐up, than those with BMI < 30 kg/m2. Associations between adiposity and adipokines were most accounted for by leptin; adjustment for leptin greatly reduced the magnitude of all associations between adiposity and remaining adipokines.

Conclusions

Increasing adiposity contributes to a worsening imbalance of pro‐ and anti‐inflammatory adipokines over time, in which leptin may have an important role as a key mediator of metabolic disease risk in Mexican Americans.
New epoxy composite thermosets with enhanced thermal conductivity and high Tg obtained by cationic homopolymerization
Authors: Isarn Isaac , Gamardella Francesco , Massagués Lluís , Fernàndez‐Francos Xavier , Serra Àngels , Ferrando Francesc
Published: February 2018

Thermal dissipation is a critical aspect for the performance and lifetime of electronic devices. In this work, novel composites based on a cycloaliphatic epoxy matrix and BN fillers, obtained by cationic curing of mixtures of 3,4‐epoxy cyclohexylmethyl 3,4‐epoxy cyclohexane carboxylate (ECC) with several amounts of hexagonal boron nitride (BN) were prepared and characterized. As cationic initiator a commercial benzylanilinium salt was used, which by addition of triethanolamine, exhibited an excellent latent character and storage stability. The effect of the formulation composition was studied by calorimetry and rheological measurements. The variation of thermal conductivity, thermal stability, thermal expansion coefficient, and thermomechanical and mechanical properties of the composites with the load of BN filler (ranging from 10 to 40 wt%) was evaluated. An improvement of an 800% (1.04 W/m·K) in thermal conductivity was reached in materials with glass transition temperatures >200°C without any loss in electrical insulation. POLYM. COMPOS., 39:E1760–E1769, 2018. © 2018 Society of Plastics Engineers
Modeling and simulation of nanocomposite based on poly propylene/graphene
Authors: Manafi Pedram , Manafi Mohammad Reza , Kehtari Karam Sasan
Published: February 2018

The use of multi‐scale model (MSM) which co‐relates the microscopic and microscopic, temperature and morphology of crystals to each other is an important factor for determination of crystallinity in nanocomposite materials. Based on the MSM, an algorithm made of a combination of “finite volume method” (FVM) and the “pixel coloring method” (PCM) is mentioned. FVM technique is used in the large coarse grid for determination of macroscopic temperature degree and PCM is used for fine scale for investigation of the morphology of crystalline structure. In this article, role of cooling rate, the initial temperature and density of nucleation is studied. It is a novel study that is a combination of MSM with a multi‐scale algorithm is utilized for investigation of nanocomposite crystallization. It is proved that nucleation rate is decreased by increasing temperature and consequently spherulites having larger sizes are created. In nanocomposite samples, latent heat is appeared at 240 K, contrasting in the case of pristine polymer. These phenomena are due to the fact that nanoparticles produce a very large number of nucleating sites. POLYM. COMPOS., 40:E993–E1005, 2019. © 2018 Society of Plastics Engineers
Peptide therapeutics that directly target transcription factors
Authors: Inamoto Ichiro , Shin Jumi A.
Published: February 2018

Transcription factors regulate gene expression in cells and control cellular development, function, and death. Dysregulation of transcription factors is often associated with disease, including cancer. As such, transcription factors are attractive targets for design of therapeutics against disease. Transcription factors function using protein‐protein and protein‐DNA interactions that occur over relatively large surface areas: this lack of a small and defined “ligand binding site” has proven to be challenging to target with small molecules. Peptide therapeutics, therefore, provide an alternate approach toward design of inhibitory agents. Transcription factors are conveniently modular by design: just the small domain that is responsible for the transcription factor's DNA binding or a protein‐protein interaction or another function, can serve as the basis for novel peptide therapeutics. In this review, examples of peptides that directly interfere with transcription factors will be discussed.
Meropenem and Vaborbactam: Stepping up the Battle against Carbapenem‐resistant Enterobacteriaceae
Authors: Jorgensen Sarah Christina Jane , Rybak Michael Joseph
Published: February 2018

Vaborbactam (VAB; formerly RPX7009) is a novel beta‐lactamase inhibitor based on a cyclic boronic acid pharmacophore with potent inhibitory activity against Ambler class A and C beta‐lactamases. It has been co‐formulated with meropenem to restore its activity against Klebsiella pneumoniae carbapenemases (KPC). VAB does not inhibit class B or D carbapenemases, nor does it improve the activity of meropenem against multidrug‐resistant nonfermenting gram‐negative bacilli, notably Acinetobacter spp. and Pseudomonas aeruginosa. The purpose of this article is to review existing data pertaining to the biochemistry, mechanism of action, pharmacokinetics/pharmacodynamics, in vitro activity, and current progress in clinical trials of meropenem and VAB (MV). Phase 1 studies have demonstrated single and multiple doses of VAB up to 2000 mg, alone or in combination with meropenem 2000 mg administered as a prolonged infusion over 3 hours, are well tolerated with an adverse effect profile similar to that of meropenem monotherapy. The available data suggest preexisting resistance among KPC‐producing isolates is rare. Strains with elevated MICs have been characterized by multiple resistance determinants including porin defects, increased drug efflux, and increased blaKPC expression. It remains uncertain whether multifactorial resistance will emerge during MV treatment and with more widespread use. Early data are positive for complicated urinary tract infections and MV compared with best available therapy in patients with serious carbapenem‐resistant Enterobacteriaciae (CRE) infections. As clinicians contemplate how to incorporate MV into CRE treatment strategies, it will be important to track and understand resistance, discern the role, if any, of combination therapy in enhancing efficacy and/or preserving activity, and define the specific therapeutic niche of MV among the expanding anti‐CRE armamentarium.
Dispersion of carbon nanotubes in ultrahigh‐molecular‐weight polyethylene by melt mixing dominated by elongation stress
Authors: Xiaochun Yin , Yang Li , Guangjian He , Yanhong Feng , Jingsong Wen
Published: February 2018

A novel melt‐mixing method and corresponding mixer for polymer materials are reported. The effects of carbon nanotube (CNT) loading, rotation rate and mixing time on the morphology and properties of CNTs/ultrahigh‐molecular‐weight polyethylene (UHMWPE) nanocomposites were experimentally investigated in detail using the mixer. Homogeneous dispersion of CNTs in intractable UHMWPE is successfully realized without the aid of any additives or solvents. Differential scanning calorimetry results showed that the crystallinity increases 13.8% when 1 wt% of CNTs is added into the composites. The maximum crystallinity increased 13.5% and then decreased slightly with increasing rotation rate. The mixing time had little effect on crystallinity. Rheological tests reveal that the effect of CNT loading on the storage modulus/complex viscosity is a result of competition between the viscosity decrease due to the selective adsorption of UHMWPE onto CNT surfaces and the viscosity increase caused by the formation of an interconnected polymer–nanotube network. The storage modulus/complex viscosity decreased with increasing rotation rate/mixing time. This is a synergic result of the selective adsorption of the long molecular chains onto the CNT surface and their thermomechanical degradation. The results showed that the mixing process dominated by elongation stress is a simple, efficient green way to prepare CNTs/UHMWPE nanocomposites via melt mixing. © 2018 Society of Chemical Industry
Effects of crosslinking agents on the physical properties of polyimide/amino‐functionalized graphene oxide hybrid films
Authors: Jeong Keuk‐Min , Li Yuheng , Yoo Dae‐Geon , Lee Nam‐Kyoung , Lee Hyeok‐Gi , Ando Shinji , Ha Chang‐Sik
Published: February 2018

The effects of crosslinking agents (crosslinkers) on polyimide (PI)/graphene oxide (GO) hybrid films were extensively investigated. The surface of GO was modified with amino groups using 4‐aminobenzylamine to improve compatibility with pyromellitic dianhydride/4,4′‐oxydianiline PI, and two kinds of crosslinkers were used: tris(4‐aminophenyl)amine and 1,3,5‐triazine‐2,4,6‐triamine (melamine). The mechanical, thermal and optical properties of the PI hybrid films were investigated. In particular, the transparency and physical properties of the PI hybrid films containing amino‐functionalized GO with homogeneous dispersion were improved. As the content of the crosslinker increased, a crosslinking network was formed between the PI chains, and the stiffness of the hybrid films was increased. The glass transition temperature, heat resistance and mechanical properties were also enhanced. The PI hybrids prepared with a rigid crosslinker exhibited higher optical transparency due to the reduction of the intermolecular charge transfer interactions with increasing interchain spacing between the PI chains. © 2018 Society of Chemical Industry
Comparing side chain packing in soluble proteins, protein‐protein interfaces, and transmembrane proteins
Authors: Gaines J. C. , Acebes S. , Virrueta A. , Butler M. , Regan L. , O'Hern C. S.
Published: February 2018

We compare side chain prediction and packing of core and non‐core regions of soluble proteins, protein‐protein interfaces, and transmembrane proteins. We first identified or created comparable databases of high‐resolution crystal structures of these 3 protein classes. We show that the solvent‐inaccessible cores of the 3 classes of proteins are equally densely packed. As a result, the side chains of core residues at protein‐protein interfaces and in the membrane‐exposed regions of transmembrane proteins can be predicted by the hard‐sphere plus stereochemical constraint model with the same high prediction accuracies (>90%) as core residues in soluble proteins. We also find that for all 3 classes of proteins, as one moves away from the solvent‐inaccessible core, the packing fraction decreases as the solvent accessibility increases. However, the side chain predictability remains high (80% within
) up to a relative solvent accessibility,
, for all 3 protein classes. Our results show that
% of the interface regions in protein complexes are “core”, that is, densely packed with side chain conformations that can be accurately predicted using the hard‐sphere model. We propose packing fraction as a metric that can be used to distinguish real protein‐protein interactions from designed, non‐binding, decoys. Our results also show that cores of membrane proteins are the same as cores of soluble proteins. Thus, the computational methods we are developing for the analysis of the effect of hydrophobic core mutations in soluble proteins will be equally applicable to analyses of mutations in membrane proteins.
Minimum explosible concentrations of mist and dust clouds
Authors: Britton Laurence G. , Harrison Benjamin Keith
Published: February 2018

When hot vapor condenses the nucleation particles initially formed coalesce rapidly and exothermically. Most of the heat of coalescence is released in less than a millisecond while droplets are less than 100 nm diameter. Consequently, the heat is released close to the source of the vapor and has no effect on dispersion. Coagulation rate is governed by an inverse square law with respect to number density; calculations showed that a vapor cloud initially within its flammable range should produce droplets smaller than 10 µm after a minute of coalescence. Such micronized droplets completely vaporize in flame preheat zones and behave as premixed vapors rather than as individual droplets; this characteristic is not due to the increased surface energy accompanying subdivision into micronized droplets but to short evaporation times in the thick preheat zones of limit flames. Droplet growth time is a nonlinear function of cloud mass concentration and if the latter exceeds about 10 times the minimum explosible concentration (MEC), droplets quickly grow to above 20–40 µm. These larger droplets tend to burn individually and the estimation of MEC becomes complicated, although rain‐out of large droplets might hasten dispersal to below the MEC.

With the assumption that micronized crystalline organic materials behave similarly to liquid droplets, we derive “intrinsic” MEC values for both hydrocarbons and a series of CHOxfuels having increasing O:C ratios. In each case, the MEC attains a constant “terminal value” as carbon number is increased. Terminal MEC values are 40 g m−3for CH (hydrocarbons), 50 g m−3for CHO (aldehydes, ethers, etc.), 60 g m−3for CHOO (esters), 67 g m−3(polyethylene glycols), and 103 g m−3(carbohydrates). MEC values for CHO and CHOO decrease rapidly with increased carbon number since additional hydrocarbon units dilute the functional oxygen group. For polyethylene glycols and carbohydrates, the MEC is less dependent on carbon number since oxygen is contained in a repeating group. Although scission and/or decomposition replace simple evaporation as carbon number increases, flash pyrolysis data for polyethylene in air show that the products of decomposition can have little effect on MEC. Nevertheless, owing to experimental deficiencies published MEC values for polyethylene are as low as 10–30 g m−3. Of the many factors affecting MEC tests, we focus on the effects of gravity and flame radiation. Radiation not only affects MEC but also the burning rates of metal dusts such as titanium; such tests should be carried out on an adequately large scale. © 2017 American Institute of Chemical Engineers Process Process Saf Prog 37:4–17, 2018
Development of an attract‐and‐infect system to control Rhynchophorus ferrugineus with the entomopathogenic fungus Beauveria bassiana
Authors: Dembilio Óscar , Moya Pilar , Vacas Sandra , Ortega‐García Lola , Quesada‐Moraga Enrique , Jaques Josep A , Navarro‐Llopis Vicente
Published: February 2018

BACKGROUND

A new Beauveria bassiana‐based attract and infect device (AID) to control Rhynchophorus ferrugineus Olivier (Coleoptera: Curculionidae) was developed. The virulence and persistence of the fungal formulation used in the AID were evaluated in the laboratory. Semi‐field and field trials were carried out to validate the results and establish the potential of this device as a control tool.

RESULTS

In laboratory conditions, a 50% lethal time (LT50) of 4.33 days was obtained when adults (7–10 days old) were exposed to the inoculation tunnel (IT) containing 1 × 1010 conidia g–1 in an oil‐based fungal formulation. This formulation maintained conidium viability at 50% for up to 2 months. Moreover, when adults were exposed to 2.5‐month field‐aged ITs, mortality still reached 50% 40 days after exposure. In addition, no differences were observed between ITs aged in early spring and those aged in summer, suggesting that the fungal formulation is not strongly affected by environmental factors in Mediterranean basin conditions. Semi‐field assays showed that the device allowed an easy transit of weevils through the IT, which were effectively attracted and infected. Using the AIDs in 4‐ha plot field trials, a reduction of >50% in the percentage of infested sentinel palms was obtained.

CONCLUSION

Based on the results obtained in terms of the efficacy and persistence of this new AID in the field and its potential in reducing R. ferrugineus populations and palm infestation, this device could become a key tool for the management of R. ferrugineus. © 2018 Society of Chemical Industry
A probabilistic verification score for contours: Methodology and application to Arctic ice‐edge forecasts
Authors: Goessling H. F. , Jung T.
Published: February 2018

We introduce a verification score for probabilistic forecasts of contours – the Spatial Probability Score (SPS). Defined as the spatial integral of local (Half) Brier Scores, the SPS can be considered the spatial analogue of the Continuous Ranked Probability Score (CRPS). Applying the SPS to idealized ensemble forecasts of the Arctic sea‐ice edge in a global coupled climate model, we demonstrate that the metric responds in a meaningful way to ensemble size, spread, and bias. When applied to individual forecasts or ensemble means (or quantiles), the SPS is reduced to the ‘volume’ of mismatch, which in the case of the ice edge corresponds to the Integrated Ice Edge Error (IIEE). By comparing initialized forecasts with climatological and persistence forecasts, we confirm earlier findings on the potential predictability of the Arctic sea‐ice edge from a probabilistic viewpoint. We conclude that the SPS is a promising probabilistic verification metric, for contour forecasts in general and for ice‐edge forecasts in particular.
Towards an along‐track validation of HOAPS precipitation using OceanRAIN optical disdrometer data over the Atlantic Ocean
Authors: Burdanowitz Jörg , Klepp Christian , Bakan Stephan , Buehler Stefan A.
Published: February 2018

The Hamburg Ocean Atmosphere Parameters and fluxes from Satellite data (HOAPS) passive‐microwave precipitation scan product is compared with the Ocean Rainfall And Ice‐phase precipitation measurement Network (OceanRAIN) surface‐based precipitation reference dataset over the global ocean. For the first time, we apply statistical point‐to‐area adjustments and along‐track averaging to ship‐based OceanRAIN precipitation data over the Atlantic Ocean to represent collocated precipitation rates better within a HOAPS satellite pixel. The statistical adjustments reduce the HOAPS–OceanRAIN root‐mean‐square error strongly from 2.65 to 1.01 mm/hr. Overall, the point‐to‐area effect impacts HOAPS–OceanRAIN differences more strongly than the precipitation regime. Higher‐resolution satellite data indicate that these adjustments work best for the most convective‐like precipitation cases, while some rather stratiform‐like precipitation cases would need no adjustment. Excluding precipitation rates below the HOAPS sensitivity threshold of 0.3 mm/hr reduces the difference in average precipitation rates between HOAPS hits and false detections combined and OceanRAIN hits and misses combined to 2%. This precipitation‐rate difference lies below the uncertainty obtained from resampling of about 10%. Without false detections, the HOAPS precipitation rate of hits‐only exceeds that of OceanRAIN by 50%. Most of the HOAPS false detections follow from cases when precipitation occurs within the HOAPS pixel but off the ship track. Consequently, these apparent false detections lead to an overestimation of HOAPS precipitation rates compared with OceanRAIN, particularly in the inner Tropics and partly the midlatitudes, where clustered convective precipitation occurs most frequently. Misses cause underestimated HOAPS precipitation rates, mainly in mid and high latitudes. However, for a HOAPS validation, apparent false detections need to be considered in addition to hits of OceanRAIN precipitation rates, to which we successfully applied statistical point‐to‐area adjustments.
Revisiting Fisher's approach to the handling of horizontal spatial correlations of observation errors in a variational framework
Authors: Michel Yann
Published: February 2018

A long‐standing issue in atmospheric data assimilation is that only a fraction of the available observations are used in the analysis. This is especially true for satellite data, which undergo channel selection and are thinned to coarser spatial and temporal resolutions. Up to now, horizontal spatial correlations of observation errors have not been fully accounted for. However, we may expect progress in forecast quality from the assimilation of spatially dense no‐thinned data while accounting for correlated errors, as this may provide a better constraint on the initial conditions at smaller scales.

This article addresses the handling of the observation‐error covariance matrix when the number of observations is large (e.g. above a few thousand). In variational methods, the analysis usually requires evaluation of products with the inverse observation‐error covariance matrix; however, the lack of structure and the size of the problem make it difficult to invert this matrix with direct approaches.

A method has been proposed several years ago by M. Fisher, in which an observation‐error covariance matrix is built from a sequence of operators. The Lanczos algorithm is then used to provide a low‐rank eigenvalue decomposition of the correlation matrix, which is regularized and explicitly inverted. This article elaborates on this method, with application to the so‐called Spinning Enhanced Visible and Infrared Imager (SEVIRI) on board Meteosat Second Generation for the convective‐scale model of Météo‐France.

We analyze the implications of truncating the eigenspectrum. We show that both the modelled spatial correlations and the variances are affected by truncation noise. The noise in the variance, in particular, is linked with the local density of the observations. Overall, several hundred eigenpairs may be required to obtain a fair representation of the covariances. While computationally expensive, this method can be used as a baseline to evaluate other approaches.
Megha‐tropiques SAPHIR radiances in a hybrid 4D‐Var data assimilation system: Study of forecast impact
Authors: Kumar Sumit , Indira Rani S. , George John P. , Rajagopal E. N.
Published: February 2018

Assimilation of microwave humidity channels from various satellites plays a key role in numerical weather prediction (NWP), especially over the Tropics. This article examines various characteristics and the impact of assimilation of Megha‐Tropiques SAPHIR (Sondeur Atmosphérique du Profil ďHumidité Intertropicale par Radiométrie) microwave radiances on model forecasts along with that of other similar microwave humidity sensors. A hybrid 4D‐Var scheme is used for assimilation of these observations, and forecasts are carried out using an advanced global atmospheric model, National Centre for Medium Range Weather Forecasting (NCMRWF) Unified Model (NCUM). The impact of SAPHIR radiances along with similar kinds of sensors have been studied using adjoint‐based Forecast Sensitivity to Observations (FSO) and Observing System Experiments (OSEs). The lowest altitude peaking channel of SAPHIR (183 ± 11 GHz) has the highest beneficial impact on the forecast compared to other channels of the same instrument and other similar instruments on board other satellites. FSO experiments show SAPHIR and Microwave Humidity Sounder (MHS) observations complement each other by having the higher beneficial impact in the lower and upper troposphere, respectively. The other microwave humidity sounders have less or negligible impact in comparison to SAPHIR/MHS, both globally and over the Indian region. An OSE shows that SAPHIR radiances assimilation influences the humidity and wind forecast of the tropical troposphere, while its impact on temperature is negligible.
Impacts of afternoon and evening sea‐breeze fronts on local turbulence, and on CO2 and radon‐222 transport
Authors: Arrillaga Jon A. , de Arellano Jordi Vilà‐Guerau , Bosveld Fred , Baltink Henk Klein , Yagüe Carlos , Sastre Mariano , Román‐Cascón Carlos
Published: February 2018

We investigated sharp disruptions of local turbulence and scalar transport due to the arrival of sea‐breeze fronts (SBFs). To this end, we employed a comprehensive 10‐year observational database from the Cabauw Experimental Site for Atmospheric Research (CESAR, the Netherlands). Sea‐breeze (SB) days were selected using a five‐filter algorithm, which accounts for large‐scale conditions and a clear mesoscale‐frontal signal associated with the land–sea contrast. Among those days (102 in all, 8.3%), based on the value of the sensible‐heat flux at the onset of SB, we identified three atmospheric boundary‐layer (ABL) regimes: convective, transition and stable. In the convective regime, the thermally driven convective boundary layer is only slightly altered by a small enhancement of the shear when the SBF arrives. Regarding the transition regime, we found that the ABL afternoon transition is accelerated. This was quantified by estimating the contributions of shear and buoyancy to the turbulent kinetic energy. Other relevant disruptions are the sharp reduction in ABL depth (∼250 m/hr) and the sudden increase in average wind speed (> 2 m/s). In the stable regime, the arrival of the SB leads to disturbances in the wind profile at the surface layer. We observed a deviation of more than 1 m/s in the observed surface‐layer wind profile compared with the profile calculated using Monin–Obukhov Similarity Theory (MOST). Our findings furthermore reveal the determinant role of the SB direction in the transport of water vapour, CO2 and 222Rn. The return of continental air masses driven by the SB circulation generates sharp CO2 increases (up to 14 ppm in half an hour) in a few SB events. We suggest that the variability in 222Rn evolution may also be influenced by other non‐local processes such as the large‐scale footprint from more remote sources.
How well were the early 2017 California Atmospheric River precipitation events captured by satellite products and ground‐based radars?
Authors: Wen Yixin , Behrangi Ali , Chen Haonan , Lambrigtsen Bjorn
Published: February 2018

In January and February of 2017, California experienced multiple heavy storms that caused serious destruction of facilities and economic loss, although it also helped to reduce water storage deficit due to prolonged drought in previous years. These extreme precipitation events were mainly associated with Atmospheric Rivers (ARs) and brought about 174 km3 of water to California according to ground observations. This article evaluates the performance of six commonly used satellite‐based precipitation products (IMERG, 3B42RT, PERSIANN, CCS, CMORPH and GSMaP), as well as ground‐based radar products (Radar‐only and Radar‐lgc) in capturing the ARs precipitation rate and distribution. It is found that precipitation maps from all products present heavy precipitation in January and February, with more consistent observations over ocean than land. Though large uncertainties exist in quantitative precipitation estimation (QPE) over land, the ensemble mean of different remote‐sensing precipitation products over California is consistent with gauge measurements. Among the six satellite‐based products, IMERG correlates the best with gauge observations both in the detection and quantification of precipitation, but it is not the best product in terms of root‐mean‐square error or bias. Compared to satellite products, ground weather radar shows better precipitation detectability and estimation skill. However, neither radar nor satellite QPE products have good performances in quantifying the peak precipitation intensity during the extreme events, suggesting that further advancement in quantification of extremely intense precipitation associated with ARs in the western United States is needed.
An observational study of the variability of East African rainfall with respect to sea surface temperature and soil moisture
Authors: Wenhaji Ndomeni C. , Cattani E. , Merino A. , Levizzani V.
Published: February 2018

Rainfall from the October–November–December (OND) short rains season over East Africa (EA, 5°S–20°N, 28–52°E) were analysed during the 1983–2010 period using state‐of‐the‐art observational datasets. Links among satellite‐derived rainfall (Climate Hazards group InfraRed Precipitation with Station data, CHIRPS), sea surface temperature (Hadley Centre Sea ice and Sea Surface Temperature, HadISST1‐SST), soil moisture (Climate Change Initiative, CCI‐SM), and dynamical variables (European Centre for Medium‐Range Weather Forecasts Re‐Analysis, ERA‐Interim) are investigated to disentangle their specific role in shaping the rainfall variability over the region. In general, interannual rainfall variability is highest in the area during OND. Empirical orthogonal function (EOF) analysis is applied to the rainfall dataset to extract the dominant spatial and temporal patterns of variability. Results show that the rainfall variability is directly influenced by the SST variability in the Indian Ocean (Indian Ocean Dipole, IOD) and in the Pacific Ocean (El Niño–Southern Oscillation, ENSO), and by the local SM. The strong positive correlation (0.78) between EA short rain index and the IOD index indicates that the positive‐phase IOD (IOD+) plays a dominant role in driving OND rainfall. Moreover, IOD+ usually coincides with El Niño events and becomes stronger as the intensity of El Niño increases for years of joint events, and the Walker circulation is shifted accordingly. Furthermore, El Niño alone brings a reduction of rainfall over EA. The physical mechanism explaining the IOD+ link to EA rainfall consists of a Gill‐type response to warm western Indian Ocean SST anomalies that induces anomalous low‐level easterlies over the IO and leads to moisture convergence over EA. In general, the response of rainfall is opposite during the negative phase of the events (IOD− and La Niña).
Variational particle smoothers and their localization
Authors: Morzfeld M. , Hodyss D. , Poterjoy J.
Published: February 2018

Given the success of 4D‐variational methods (4D‐Var) in numerical weather prediction, and recent efforts to merge ensemble Kalman filters with 4D‐Var, we revisit how one can use importance sampling and particle filtering ideas within a 4D‐Var framework. This leads us to variational particle smoothers (varPS) and we study how weight‐localization can prevent the collapse of varPS in high‐dimensional problems. We also discuss the relevance of (localized) weights in near‐Gaussian problems. We test our ideas on the Lorenz'96 model of dimensions n = 40, n = 400, and n = 2,000. In our numerical experiments the localized varPS does not collapse and yields results comparable to ensemble formulations of 4D‐Var, while tuned EnKFs and the local particle filter lead to larger estimation errors. Additional numerical experiments suggest that using localized weights may not yield significant advantages over unweighted or linearized solutions in near‐Gaussian problems.
Parameter and state estimation with ensemble Kalman filter based algorithms for convective‐scale applications
Authors: Ruckstuhl Y. M. , Janjić T.
Published: February 2018

Representation of clouds in convection‐permitting models is sensitive to numerical weather prediction (NWP) model parameters that are often very crudely known (for example roughness length). Our goal is to allow for uncertainty in these parameters and estimate them from data using the ensemble Kalman filter (EnKF) approach. However, to deal with difficulties associated with convective‐scale applications, such as non‐Gaussianity and constraints on state and parameter values, modifications to classical EnKF are necessary. In this article, we evaluate and extend several recently developed EnKF‐based algorithms that either incorporate constraints such as mass conservation and positivity of precipitation explicitly or introduce higher order moments on the joint state and parameter estimation problem. We compare their results with the localized EnKF for a common idealized test case. The test case uses perfect model experiments with the one‐dimensional modified shallow‐water model, which was designed to mimic important properties of convection. We use a stochastic dynamical model for parameters, in order to prevent underdispersion in parameter space. To deal with localization for estimation of parameters, we introduce a method called global updating, which is a computationally cheap modification of spatial updating and was proven successful in this context. The sensitivity of the results to the number of ensemble members and localization, as well as observation coverage and frequency, is shown. Although all algorithms are capable of reducing the initial state and parameter errors, it is concluded that mass conservation is important when the localization radius is small and/or the observations are sparse. In addition, accounting for higher order moments in the joint space and parameter estimation problem is beneficial when the ensemble size is large enough or when applied to parameter estimation only.
Experimental measurements of charge separation under wet growth conditions
Authors: Luque M. Y. , Bürgesser R. E. , Ávila E. E.
Published: February 2018

In this work we present the results of experimental measurements of the charge transferred to simulated graupel under wet growth conditions. The range of temperature was between −7 and −18 °C. The speeds of collision employed in the measurements were between 8 and 13 m/s with the goal of representing graupel of different initial densities. The aim of this study was to corroborate the existence of charge transfer under wet growth. The results show the presence of positive charge when graupel reaches partial wet growth, and the magnitude of this charge is comparable to the charge transferred under dry growth conditions. On the other hand, when total wet growth is reached no charge transfer is registered. This leads to the conclusion that the non‐inductive mechanism could be working under partial wet growth conditions when the ice crystals collide with the dry regions of the graupel surface and then bounce off.
Humanitarian Logistics at a Crossroads: How Logisticians Reconcile Their Professional and Humanitarian Identities in Response to Tougher Host Government Regulations
Authors: Dube Nonhlanhla , Broekhuis Manda
Published: February 2018

Humanitarian aid workers increasingly experience pressure to professionalize their services in order to ensure more efficient and effective assistance to disaster victims. Particularly for logisticians, this pressure is also the result of increasingly tough regulations imposed by host governments. This causes a dilemma for aid workers: Professionalization can be at odds with their humanitarian values and principles, such as providing unhindered assistance, without discrimination, to whoever needs it. This research explores how humanitarian logisticians experience and deal with this dilemma. In particular, how they reconcile humanitarian values and principles on the one hand with their (developing) professional standards and practices on the other. Theoretical concepts on professionalization, social identity, and so‐called boundary work are used to analyze the problem. Results show that individual logisticians adopt one of four distinct identities when approaching reconciliation, namely: Professional‐dominance, intersection, union, or humanitarian‐dominance identities. The associated approaches inform how they engage with stakeholders and make decisions. Each approach has its benefits and shortcomings in various operational settings. This implies there is a need to further establish the settings in which each approach delivers the best logistics performance.