bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of weighted average cost of capital, capital expenditure, and other parameters on future utility‐scale PV levelised cost of electricity
Authors: Vartiainen Eero , Masson Gaëtan , Breyer Christian , Moser David , Román Medina Eduardo
Published: August 2019

Solar photovoltaics (PV) is already the cheapest form of electricity generation in many countries and market segments. Market prices of PV modules and systems have developed so fast that it is difficult to find reliable up to date public data on real PV capital (CAPEX) and operational expenditures (OPEX) on which to base the levelised cost of electricity (LCOE) calculations. This paper projects the future utility‐scale PV LCOE until 2050 in several European countries. It uses the most recent and best available public input data for the PV LCOE calculations and future projections. Utility‐scale PV LCOE in 2019 in Europe with 7% nominal weighted average cost of capital (WACC) ranges from 24 €/MWh in Malaga to 42 €/MWh in Helsinki. This is remarkable since the average electricity day‐ahead market price in Finland was 47 €/MWh and in Spain 57 €/MWh in 2018. This means that PV is already cheaper than average spot market electricity all over Europe. By 2030, PV LCOE will range from 14 €/MWh in Malaga to 24 €/MWh in Helsinki with 7% nominal WACC. This range will be 9 to 15 €/MWh by 2050, making PV clearly the cheapest form of electricity generation everywhere. Sensitivity analysis shows that apart from location, WACC is the most important input parameter in the calculation of PV LCOE. Increasing nominal WACC from 2 to 10% will double the LCOE. Changes in PV CAPEX and OPEX, learning rates, or market volume growth scenarios have a relatively smaller impact on future PV LCOE.
Longitudinal disciplinary and achievement outcomes associated with school‐wide PBIS implementation level
Authors: James Anthony G. , Noltemeyer Amity , Ritchie Rachel , Palmer Katelyn , University Miami
Published: August 2019

Positive behavioral interventions and support (PBIS) is a multitiered framework for behavioral support that is being increasingly implemented in schools. Although research has linked PBIS to improved student outcomes, less research is longitudinal and considers both academic and behavioral outcomes. This study examined the relationships between changes in school‐wide (i.e., Tier I) PBIS implementation level and changes in disciplinary and achievement outcomes over a 2‐year period. Participants included 85 Ohio schools with data on PBIS implementation fidelity (from the tiered fidelity inventory, or TFI), out‐of‐school suspensions (OSSs), and statewide achievement tests for the 2015–2016 and 2016–2017 school years. Linear regressions were conducted to examine the degree to which changes in TFI Tier I scores predicted changes in OSS and achievement scores when controlling for school‐level demographic variables that also were related to the outcome variables. Changes in TFI Tier I scores was found to significantly predict changes in OSS per 100 students but not changes in achievement scores.
An in‐line high frequency flow interrupter applied to nasal CPAP: Improved carbon dioxide clearance in a premature infant lung model
Authors: Sivieri Emidio M. , Eichenwald Eric C. , Rub David M. , Abbasi Soraya
Published: August 2019

Background

Noninvasive respiratory support continues to have high failure rates in small preterm infants. We previously demonstrated significantly improved in vitro CO2 washout by applying oscillations to a high flow nasal cannula system.

Objective

To develop a high frequency flow interrupter that could be applied to commonly used nasal continuous positive airway pressure (NCPAP) devices and to determine the effect of oscillations on end‐tidal carbon dioxide (EtCO2) levels in an infant lung model.

Design/Methods

NCPAP was applied to a premature infant lung simulator using either bubble (BCPAP) or variable‐flow (VCPAP) CPAP. Supply gas was interrupted with a solenoid pinch valve. EtCO2 was measured before and during oscillation and repeated at 4, 6, 8, 10, and 12 Hz oscillation and CPAP pressures of 4, 6, and 8 cm H
2O.

Results

BCPAP and VCPAP EtCO2 levels decreased with oscillation (P < .001). BCPAP EtCO2 was significantly dependent on oscillation frequency (P < .001) with decreases of 18% to 47% and maximum effect at 10 Hz. Optimum VCPAP CO2 clearance occurred at 6 Hz with reductions of 30% and 39% at 6 and 8 cm H2O CPAP respectively. BCPAP and VCPAP mean airway pressures remained unchanged transitioning from nonoscillation to oscillation. Oscillated BCPAP and VCPAP average amplitudes were 8.3 ± 0.5 and 8.4 ± 2.3 SD cm H2O, respectively. Power spectrum analysis of non‐oscillated BCPAP showed bubbling‐only dominant peaks at 10 to 12 Hz corresponding with the maximum BCPAP EtCO2 reductions.

Conclusion

Application of high frequency oscillation to NCPAP improves CO2 clearance in a premature infant lung model. This simple modification to NCPAP delivery devices may prove to be an effective enhancement of this mode of noninvasive respiratory support.
Mitigating the effect of language in the assessment of science: A study of English‐language learners in primary classrooms in the United Kingdom
Authors: Afitska Oksana , Heaton Timothy J.
Published: August 2019

Children coming from homes where English is not their first language constitute a significant and increasing proportion of classrooms worldwide. Providing these English‐language learners (ELLs) with equitable assessment opportunities is a challenge. We analyze the performance of 485 students, both English‐native‐speakers (ENSs) and ELLs, across five schools within the United Kingdom in the 7–11‐year age group on standardized summative Science assessment tasks. Logistic regression with random effects assesses the impact of English‐language proficiency, and its interactions with question traits, on performance. Traits investigated were: question focus; need for active language production; presence/absence of visuals; and question difficulty. Results demonstrated that, while ELLs persistently performed more poorly, the gap to their ENS peers depended significantly upon assessment traits. ELLs were particularly disadvantaged when responses required active language production and/or when assessed on specific scientific vocabulary. Presence of visual prompts did not help ELL performance. There was no evidence of an interaction between topic difficulty and language ability suggesting lower ELL performance is not related to capacity to understand advanced topics. We propose assessment should permit flexibility in language choice and production type for ELLs with low English language proficiency; while simultaneously recommend subject‐specific teaching of scientific language begins at lower stages of schooling.
Toward a practice‐based theory for how professional learning communities engage in the improvement of tools and practices for scientific modeling
Authors: Thompson Jessica J. , Hagenah Sara , McDonald Scott , Barchenger Christie
Published: August 2019

To organize for the improvement of science instruction teachers need opportunities to collaboratively learn from practice, in practice, and to engage in the revision of classroom tools. In this paper, we examine how a professional learning community (PLC), comprised of middle school teachers and researchers, worked on the improvement of Ambitious Science Teaching (AST) practices and developed instructional practices and tools supporting model‐based inquiry. This paper focuses on the first year of a 5‐year research–practice partnership in which teachers and researchers routinely coplanned, cotaught, and codebriefed science lessons via improvement cycles. We conducted an analysis of teacher‐designed tools, reflective talk, and classroom observations. All teachers engaged in increasingly sophisticated forms of AST practices over the year and began to use a similar tool to scaffold scientific modeling with students. Yet, there were two distinct variations that evolved with grade‐level teams. One team developed a practice and tool supporting students’ final form articulation of ideas with models and the other team developed a practice and tools supporting the revision of models over a unit of instruction. We argue that both grade‐level teams engaged in productive learning and that PLC benefited from having different perspectives on relatively similar practices for scaffolding students’ scientific modeling. On the basis of the findings, we propose three key components to a practice‐based theory for how PLCs negotiate tools as a part of the improvement of teaching practices: anchoring improvement in a particular tool and practice, supporting variation in teacher learning and making teachers’ pedagogical reasoning explicit.
A tale of two camps: A mixed methods investigation into racially disparate outcomes in a nanotechnology research experience
Authors: Mutegi Jomo W. , Sorge Brandon , Fore Grant A. , Gibau Gina S.
Published: August 2019

This mixed methods study reports data from the implementation of a 2‐week nanotechnology camp for secondary level students. The camp, Nanotechnology Experiences for Students and Teachers, had the overarching goal of increasing science, technology, engineering, and mathematics (STEM) interest among the next generation of potential STEM professionals. Statistical pre‐ and postsurvey data indicate that overall the camp was successful in fostering increased STEM interest among participants. However, early analysis of ethnographic data showed that African American students were observed to have radically different experiences than the non‐African American students. To better understand why the camp yielded such divergent outcomes, we examined ethnographic data focusing specifically on incidents of microaggressions. We were particularly interested in the impact that microaggressions had on African American students’ camp experience and learning. Our data show that microaggressions were pervasive; they came from students, instructors, and the environment; and in response, African American students adopted detachment‐coping strategies. Together these factors worked against African American students’ success. We conclude with suggestions for practice.
Synthesis of H4Mn5O12 Nanotubes Lithium Ion Sieve and Its Adsorption Properties for Li+ from Aqueous Solution
Authors: Xu Naicai , Li Sixia , Guo Min , Qian Zhiqiang , Li Wu , Liu Zhong
Published: August 2019

Li4Mn5O12 with nanotubes morphology was successfully prepared by hydrothermal and solid phase reaction. The as‐obtained adsorbent was determined by X‐ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) and N2 ad/desorption technologies. The characterization results indicated that spinel H4Mn5O12 took on two‐dimensional nanotubes morphology with the diameter of pore ∼200 nm, BET surface area is 92.997 m2⋅g−1, and the corresponding pore size centers at 3.4, 35.9 and 156.5 nm. The adsorption experimental results showed that the maximum Li+ adsorption capacity of H4Mn5O12 was as high as 37.0 mg⋅g−1, and the adsorption process fit well with Langmuir model. In addition, adsorption kinetic experimental data were well fitted by the pseudo‐second‐order model, which indicated the adsorption process followed chemisorption involving in ion exchange. The effects of co‐existing cations on lithium recovery suggested that Na+, K+, Ca2+ and Mg2+ ions had very small effect on recovery of lithium. The regeneration of H4Mn5O12 for the multicyclic Li+ adsorption and desorption were also assessed. The result implied that most of Li+ could be desorbed within 40 min, but the adsorption capacity decreased when the number of cycles was five, which indicated that the structure of H4Mn5O12 was needed to be improved. Lithium adsorption onto H4Mn5O12 could be attributed to electrostatic interaction and ion exchange between Li+ and H+ according to the results of adsorption isotherm and kinetics properties.
A Light‐Up Fluorescent Probe for Detection of Formaldehyde in Serum and Gaseous Based on d‐PeT Process
Authors: Chen Hui , Zhou Yang , Zheng Kaibo , Zhang Nuonuo , Tan Xuecai , Chen Weifeng
Published: August 2019

A new Light‐Up fluorescent probe (FA‐P) for detection of formaldehyde was designed and synthesized based on the donor‐excited photo induced electron transfer (d‐PeT) process. The probe FA‐P was constructed by integrating a benzothiazole derivatives as the fluorescent skeleton and homoallylamino group as the specific recognition site. It showed the unique advantages of easy‐preparation, and excellent selectivity response toward formaldehyde. Besides, The probe FA‐P can not only detect formaldehyde gas through the prepared test paper, but also detect formaldehyde in serum solution.
Mg2+ and Ti4+ Co–Doped Spinel LiMn2O4 as Lithium‐Ion Battery Cathode
Authors: Yang Zengrong , Wang Yujie , Chen Xianchun , Wu Hao , Zhang Yun
Published: August 2019

Herein, Mg2+ and Ti4+ co‐doped spinel LiMn2O4 lithium‐ion cathode material was prepared via a simple high‐temperature solid‐state route, presenting the high specific capacity, upgraded cyclability, and enhanced rate capability contemporaneously. The introduction of Mg2+ reducing the relative content of Mn3+ in the LiMn2O4 material could not only well restrain the Jahn‐Teller effect due to the average‐valence increment of manganese, but also highly maintain the stability of cubic spinel structure upon cycling by virtue of stronger bond energy of Mg−O compared with Mn−O. What's more, Ti4+ doping with a replacement of Mn4+ increases the lattice parameter of LiMn2O4 which could facilitate the insertion and deinsertion of Li+, and could also offer a positive effect to suppress the dissolution of manganese via changing the surface microstructure of material. Therefore, the co‐doped LiMn2O4 electrode exhibits a high Li+ storage capacity (124 mAh g−1 at 0.1 C), good capacity‐retention rate (97% after 100 cycles at 5 C), enhanced rate capability (85 mAh g−1 at 5 C) and improved cycling performance (80 mAh g−1 after 100 cycles at 5 C).
Size‐, Water‐, and Defect‐Regulated Potassium Manganese Hexacyanoferrate with Superior Cycling Stability and Rate Capability for Low‐Cost Sodium‐Ion Batteries
Authors: Zhou Aijun , Xu Zemin , Gao Hongcai , Xue Leigang , Li Jingze , Goodenough John B.
Published: August 2019

Potassium manganese hexacyanoferrate (KMHCF) is a low‐cost Prussian blue analogue (PBA) having a rigid and open framework that can accommodate large alkali ions. Herein, the synthesis of KMHCF and its application as a high‐performance cathode in sodium‐ion batteries (NIBs) is reported. High‐quality KMHCF with low amounts of crystal water and defects and with homogeneous microstructure is obtained by controlling the nucleation and grain growth by using a high‐concentration citrate solution as a precipitation medium. The obtained KMHCF exhibits superior cycling and rate performance as a NIB cathode, showing 80% capacity retention after 1000 cycles at 1 C and a high capacity of 95 mA h g−1 at 20 C. Unlike conventional single‐cation batteries, the hybrid NIB with KMHCF as cathode and Na as anode in Na‐ion electrolyte displays three reversible plateaus that involve stepwise insertion/extraction of both K+ and Na+ in the PBA framework. In later cycling, the K+–Na+ cointercalated phase is partially converted into a cubic sodium manganese hexacyanoferrate (NaMHCF) phase due to the increasing replacement of Na+ for K+.
High Amplification of the Antiviral Activity of Curcumin through Transformation into Carbon Quantum Dots
Authors: Lin Chin‐Jung , Chang Lung , Chu Han‐Wei , Lin Han‐Jia , Chang Pei‐Ching , Wang Robert Y. L. , Unnikrishnan Binesh , Mao Ju‐Yi , Chen Shiow‐Yi , Huang Chih‐Ching
Published: August 2019

It is demonstrated that carbon quantum dots derived from curcumin (Cur‐CQDs) through one‐step dry heating are effective antiviral agents against enterovirus 71 (EV71). The surface properties of Cur‐CQDs, as well as their antiviral activity, are highly dependent on the heating temperature during synthesis. The one‐step heating of curcumin at 180 °C preserves many of the moieties of polymeric curcumin on the surfaces of the as‐synthesized Cur‐CQDs, resulting in superior antiviral characteristics. It is proposed that curcumin undergoes a series of structural changes through dehydration, polymerization, and carbonization to form core–shell CQDs whose surfaces remain a pyrolytic curcumin‐like polymer, boosting the antiviral activity. The results reveal that curcumin possesses insignificant inhibitory activity against EV71 infection in RD cells [half‐maximal effective concentration (EC50) >200 µg mL−1] but exhibits high cytotoxicity toward RD cells (half‐maximal cytotoxic concentration (CC50) <13 µg mL−1). The EC50 (0.2 µg mL−1) and CC50 (452.2 µg mL−1) of Cur‐CQDs are >1000‐fold lower and >34‐fold higher, respectively, than those of curcumin, demonstrating their far superior antiviral capabilities and high biocompatibility. In vivo, intraperitoneal administration of Cur‐CQDs significantly decreases mortality and provides protection against virus‐induced hind‐limb paralysis in new‐born mice challenged with a lethal dose of EV71.
Cobalt Nanoparticles and Atomic Sites in Nitrogen‐Doped Carbon Frameworks for Highly Sensitive Sensing of Hydrogen Peroxide
Authors: Li Zehui , Liu Rongji , Tang Cheng , Wang Zhuoya , Chen Xiao , Jiang Yuheng , Wang Chizhong , Yuan Yi , Wang Wenbo , Wang Dongbin , Chen Shuning , Zhang Xiaoyuan , Zhang Qiang , Jiang Jingkun
Published: August 2019

In situ monitoring of hydrogen peroxide (H2O2) during its production process is needed. Here, an electrochemical H2O2 sensor with a wide linear current response range (concentration: 5 × 10−8 to 5 × 10−2 m), a low detection limit (32.4 × 10−9 m), and a high sensitivity (568.47 µA mm−1 cm−2) is developed. The electrocatalyst of the sensor consists of cobalt nanoparticles and atomic Co‐Nx moieties anchored on nitrogen doped carbon nanotube arrays (Co‐N/CNT), which is obtained through the pyrolysis of the sandwich‐like urea@ZIF‐67 complex. More cobalt nanoparticles and atomic Co‐Nx as active sites are exposed during pyrolysis, contributing to higher electrocatalytic activity. Moreover, a portable screen‐printed electrode sensor is constructed and demonstrated for rapidly detecting (cost ≈40 s) H2O2 produced in microbial fuel cells with only 50 µL solution. Both the synthesis strategy and sensor design can be applied to other energy and environmental fields.
Phosphorus and Yttrium Codoped Co(OH)F Nanoarray as Highly Efficient and Bifunctional Electrocatalysts for Overall Water Splitting
Authors: Zhang Gengwei , Wang Bin , Li Lu , Yang Shengchun
Published: August 2019

Rational design and synthesis of bifunctional electrocatalysts with high efficiency and low‐cost for overall water splitting is still a challenge. A simple approach is reported to prepare a phosphorus and yttrium codoped cobalt hydroxyfluoride (YP‐Co(OH)F) nanoarray on nickel foam, which displays high‐performance for both hydrogen evolution reaction (HER) and oxygen evolution reaction in alkaline solution. The codoping of yttrium and phosphorus into Co(OH)F leads to a tuned electronic environment and favorable electron transfer, thus resulting in superior water splitting activity. The YP‐Co(OH)F electrode only requires an overpotential of 238 mV to reach a current density of 10 mA cm−2 (η10), much smaller than RuO2 (302 mV). Moreover, it displays an overpotential of 55 mV at η10 for HER, similar to that of Pt/C. When YP‐Co(OH)F is used as both anode and cathode in a two‐electrode configuration, it only demands a cell potential of 1.54 V at η10, lower than the IrO2||Pt/C couple (1.6 V) as well as other recently reported electrocatalysts. It even maintains stable water splitting for 300 h. Such a two‐electrode device can be easily driven by a 1.5 V silicon solar cell in sunlight, proving the potential of the promising catalyst for large‐scale electrolytic water splitting.
A security risk mitigation framework for cyber physical systems
Authors: Zahid Maryam , Inayat Irum , Daneva Maya , Mehmood Zahid
Published: August 2019

Cyber physical systems (CPSs) are safety‐critical, be it weapon systems, smart medical devices, or grid stations. This makes ensuring security of all the components constituting a CPS unavoidable. The rise in the demand of interconnectedness has made such systems vulnerable to attacks, ie, cyberattacks. Over 170 cases of cyber‐security breaches in CPS were reported over the past two decades. An increase in the number of cyberattack incidents on CPS makes them more exposed and less trustworthy. However, identifying the security requirements of the CPS to pinpoint the relevant risks may help to counteract the potential attacks. Literature reveals that the most targeted security requirements of CPS are authentication, integrity, and availability. However, little attention has been paid on certain crucial security attributes such as data freshness and nonrepudiation. One major reason of security breaches in CPS is the lack of custom or generalized countermeasures. Therefore, we propose a security risk mitigation framework for a CPS focused on constraints, ie, authentication, data integrity, data freshness, nonrepudiation, and confidentiality. Furthermore, we evaluate the proposed work using a case study of a safety critical system. The results show a decrease in the severity of the identified security risks, ie, man‐in‐the‐middle attack, spoofing, and data tempering.
Experimental Investigation on Partition Induction Heating of High‐Strength Boron Alloyed Steel Blanks
Authors: Bao Li , Liu Weijie , Li Qi , Gu Yu , Wu Jian
Published: August 2019

To manufacture B pillars with tailored properties of car body‐in‐white, a new partition induction heating process for 22MnB5 blanks is proposed. After 30 s of heating, different temperature zones are formed on the blanks under the impact of two magnetizer shapes. The low‐temperature zone exists in the two‐phase zone, whereas the high‐temperature zone reaches the austenitic temperature. Different microstructures are formed in different temperature zones after the water quenching, as the mixed microstructures (F + M) appear in the low‐temperature zones, and 100% martensite is formed in the high‐temperature zones. As for mechanical properties, the ultimate tensile strengths in the low‐temperature zones with the presence of magnetic rings and sheets are 896 and 1038 MPa, corresponding to elongation rates of 18.6% and 17.4%, respectively. The tensile strengths in the high‐temperature zones are 1665 and 1654 MPa, corresponding to elongation rates of 16% and 16.4%, respectively. In contrast with the mechanical properties obtained in a conventional heat treatment, the new partition induction heating improves the tensile strength in the high‐temperature zones by more than 100 MPa as well as the ductility. These experimental results well underlie the subsequent experiments on randomly tailoring the low strength with higher ductility zones and shapes.
Effect of Refractory on Nonmetallic Inclusions in Si–Mn‐Killed Steel
Authors: Deng Zhiyin , Cheng Liu , Chen Lei , Zhu Miaoyong
Published: August 2019

Some laboratory experiments are carried out to study the effect of different refractories on the original and exogenous inclusions in Si–Mn‐killed steel. As expected, it is found that Al2O3 refractory causes high melting points of both SiO2–Al2O3‐MnO system and SiO2–Al2O3‐CaO system inclusions, while MgO crucible reduces the melting points of both systems of inclusions to a certain extent. The purity of MgO refractory is crucial for tire cord steel grades, and even 0.3% of Al2O3 impurity in refractory results in an evident increase (by 10%‐20%) of Al2O3 content in the inclusions. Similar to Al‐killed steel grades, MgO·Al2O3 spinel can also be stable in Si–Mn‐killed steel due to the effect of MgO refractory, and MgO and Al2O3 inclusions can transform into MgO·Al2O3 spinel. These inclusions should be strictly controlled during refining process. High‐purity and high‐quality MgO refractory as well as high‐quality alloys are recommended for Si–Mn‐killed steel grades, and Al2O3‐based refractory should be avoided.
Development and application of a new discrete element into simulation of nonlinear behavior of concrete
Authors: Mehrpay Saeid , Wang Zhao , Ueda Tamon
Published: August 2019

A new element based on the concept of Rigid Body Spring Model (RBSM) that inherently incorporates Poisson effect is developed and utilized to simulate the nonlinear behavior of concrete. Initially, the behavior of element in linear state is successfully verified. For the nonlinear applications in simulation of concrete, nonlinear material models are implemented based on mesoscale modeling technique that does not suffer from complexity of macroscopic models based on volumetric and deviatoric stress and strain tensors separation. Beside capability of incorporating the Poisson's ratio of the material, with the new material models implemented, the new element can represent the complex behavior of concrete. The uniaxial compressive and tensile test beside splitting tensile test on concrete specimen were simulated successfully and similar cracking patterns to the experiments were observed in the simulations.
Cellular mechanisms of epithelial stem cell self‐renewal and differentiation during homeostasis and repair
Authors: Das Diya , Fletcher Russell B. , Ngai John
Published: August 2019

Epithelia in adult mammals exhibit remarkable regenerative capacities owing to the presence of adult stem cells, which self‐renew and differentiate to replace cells lost to normal turnover or injury. The mechanisms supporting tissue homeostasis and injury‐induced repair often differ from each other as well as from those used in embryonic development. Recent studies have also highlighted the phenomenon of cellular plasticity in adult tissues, in which differentiated cells can change fate and even give rise to new stem cell populations to complement the canonical stem cells in promoting repair following injury. Signaling pathways such as WNT, bone morphogenetic protein, and Sonic Hedgehog play critical roles in stem cell maintenance and cell fate decisions across diverse epithelia and conditions, suggesting that conserved mechanisms underlie the regenerative capacity of adult epithelial structures.

This article is categorized under:

Gene Expression and Transcriptional Hierarchies > Regulatory Mechanisms

Adult Stem Cells, Tissue Renewal, and Regeneration > Tissue Stem Cells and Niches

Adult Stem Cells, Tissue Renewal, and Regeneration > Stem Cell Differentiation and Reversion

Adult Stem Cells, Tissue Renewal, and Regeneration > Regeneration
Bound electron stopping power model of partially stripped ions in partially ionized plasmas
Authors: Gil Juan Miguel , Beltrán Pablo R. , Rodríguez Rafael , Espinosa Guadalupe , Barriga‐Carrasco Manuel D. , González‐Gallego Luis
Published: August 2019

In this work, an expression for the bound electron stopping power of partially ionized highly energetic ions for partially ionized plasmas in the context of the Bethe approximation, in both local thermodynamic equilibrium and nonequilibrium, is presented and studied. The mean excitation energy of the stopping power incorporates a detailed description of the bound electron states of both the ion beam and plasma under different thermodynamic regimes. In the analysis carried out, we focus our attention on fully stripped ion beams in partially ionized aluminum plasmas. The temperature and electron density ranges considered were 4–100 eV and 1016–1022 cm−3, respectively.
Visions of Clean and Green
Authors: Rowe Peter G. , Hee Limin
Published: August 2019

Against this background, Lee Kuan Yew at the head of the People’s Action Party (PAP), now in the seat of power in the new Republic of Singapore, prosecuted his insight that Singapore should become a clean and green city. This was motivated, as mentioned earlier, by putting the right face on the attraction of outside foreign investment and tourism upon which Singapore was to depend. He also saw ‘clean greening’ to be a tangible way of addressing inequality throughout the island and, finally, as an opportunity to create an identity for residents and a sense of national pride. As elsewhere, this underlying narrative or metaphor for island-city development went through subsequent transformations. The ‘Garden City’ idea, for instance, moved on to be a ‘City in a Garden’ and then towards the end of the twentieth-century, ‘a Tropical City of Excellence’ envisioned by the URA with strong connotations of its vegetative and ‘geographical ‘green-blue’ aspect. More recently, more of a convergence into a ‘city in nature’ is emerging, with greater emphasis strongly on the identity aspect of an altogether tropical landscape in which living takes place befitting Singapore’s geographic and otherwise natural location. This latest ‘turn’ on ‘garden’ and ‘city’ also argues for greater complementarity of green and blue aspects of Singapore’s intrinsic environment. It involves efforts to intensify the planting of more native and more diversified plant species; and through multi-layered heights of plants to emulate the forest structure and to create more ecosystems providing niches for different fauna species. The plantings are thus carefully curated in the beginning but will be left to grow and evolve naturally to produce a naturalistic rather than garden-like setting. It may also provide the rest of us with a clearer view into the successful occupation of ‘hyperobjectivity’ by beginning to invert the usual dominance of constructed over ‘natural’ environments in city making. Of course, Singapore is not alone in this strong metaphorical and influential presence of ‘natural and cultivated’ landscape qualities with those of a more constructed and technological kind, nor of the transformation of such juxtapositions over time. American ‘pastoralism’, for instance, giving way to the ‘machine in the garden’ is another such instance. Also, various rounds of ‘citta’ in ‘compagna’ in the Italian ecumen is another along with other European schemes. Indeed, it seems as if such poetics of occupied and environmental space are leit motifs of civilization. The key point here, though, is that what Singapore is beginning to tackle, so to speak, is unique and of its own making.
Parton branching at amplitude level
Authors: Forshaw Jeffrey R. , Holguin Jack , Plätzer Simon
Published: August 2019

Abstract

We present an algorithm that evolves hard processes at the amplitude level by dressing them iteratively with (massless) quarks and gluons. The algorithm interleaves collinear emissions with soft emissions and includes Coulomb/Glauber exchanges. It includes all orders in N

c
, is spin dependent and is able to accommodate kinematic recoils. Although it is specified at leading logarithmic accuracy, the framework should be sufficient to go beyond. Coulomb exchanges make the factorisation of collinear and soft emissions highly non-trivial. In the absence of Coulomb exchanges, we show how factorisation works out and how a partial factorisation is manifest in the presence of Coulomb exchanges. Finally, we illustrate the use of the algorithm by deriving DGLAP evolution and computing the resummed thrust, hemisphere jet mass and gaps-between-jets distributions in e
+
e
−.
Octagons I: combinatorics and non-planar resummations
Authors: Bargheer Till , Coronado Frank , Vieira Pedro
Published: August 2019

Abstract

We explain how the ’t Hooft expansion of correlators of half-BPS operators can be resummed in a large-charge limit in

$$ \mathcal{N} $$

N

= 4 super Yang-Mills theory. The full correlator in the limit is given by a non-trivial function of two variables: One variable is the charge of the BPS operators divided by the square root of the number N

c
of colors; the other variable is the octagon that contains all the ’t Hooft coupling and spacetime dependence. At each genus g in the large N

c
expansion, this function is a polynomial of degree 2g + 2 in the octagon. We find several dual matrix model representations of the correlators in the large-charge limit. Amusingly, the number of colors in these matrix models is formally taken to zero in the relevant limit.
Investigating the application of reactive polymers in fluid loss control
Authors: Trifunoski Tony , Mostofi Masood
Published: August 2019

Water reactive polymers are rapid setting fluids that exhibit high viscosity after being exposed to water to control severe fluid loss. In this study, the performance of a water reactive polymer is studied through a series of fluid loss experiments. Various unconsolidated and permeable formations were simulated using different sand size grades, with the change in permeability being recorded after applying the reactive polymer under different operating conditions. The results showed 62–100% permeability reductions depending on the initial value of permeability and operating conditions. In addition, the setting time of the reactive polymer was obtained at different water concentrations and temperatures by monitoring the viscosity of the reactive polymer using a Brookfield viscometer. The results indicate that a hydration time of 30 min is satisfactory to reach an acceptable viscosity for all hydration volumes tested. At lower hydration volumes, the viscosity increased rapidly at the same rate and reached the same maximum viscosity. As hydration volume increased, both the rate of increase and maximum viscosity were reduced.
Relationships between sociocultural factors (gender, immigrant and socioeconomic background), peer relatedness and positive affect in adolescents
Authors: Alivernini Fabio , Cavicchiolo Elisa , Girelli Laura , Lucidi Fabio , Biasi Valeria , Leone Luigi , Cozzolino Mauro , Manganelli Sara
Published: August 2019

Introduction

During adolescence, experiencing positive emotions at school is important for motivation as well as for academic success and psychological well‐being. In the present study, on the basis of Self‐Determination Theory (SDT), we investigated the relationships between sociocultural factors (gender, immigrant and socioeconomic background), peer relatedness (acceptance and friendship) and positive affect at school.

Methods

Data was based on a random sample of 36,712 tenth grade Italian adolescents. Their average age was 15.6 years (SD = 0.77), 50.6% were males, while 6.1% were first‐generation immigrants and 3.8% were second‐generation immigrants. Firstly, comparing latent means, we established peer relatedness and positive affect profiles of adolescents with different sociocultural backgrounds. Subsequently, we tested a structural equation model, based on SDT, according to which the effects of sociocultural factors on experiencing positive affect at school are mediated by peer relatedness dimensions.

Results

Latent mean comparisons showed that immigrant adolescents, students with a lower‐SES and girls had fewer friendships with their classmates, lower levels of positive affect at school and were less accepted by their peers. A well‐fitting structural equation model corroborated the mediating role of acceptance and friendship, which accounted for 16% of variance in positive affect.

Conclusions

Due to sociocultural factors, some groups of adolescents proved to be more at risk of being socially excluded and of experiencing less positive affect at school. Moreover, our findings support the claim of SDT that the satisfaction of basic psychological needs, such as relatedness, is more important than sociocultural factors in determining adolescents’ psychological well‐being.
The neuroprotective role of melatonin in a gestational hypermethioninemia model
Authors: Figueiró Paula W. , Moreira Daniella de S. , dos Santos Tiago M. , Prezzi Caroline A. , Rohden Francieli , Faccioni‐Heuser Maria Cristina , Manfredini Vanusa , Netto Carlos A. , Wyse Angela T.S.
Published: August 2019

Elevated levels of methionine in blood characterize the hypermethioninemia, which may have genetic or non‐genetic origin, as for example from high protein diet. Born rats from hypermethioninemic mothers presented cerebral oxidative stress, inhibition of Na+,K+‐ATPase, memory deficit and ultrastructure cerebral changes. Melatonin is a hormone involved in circadian rhythm and has antioxidant effects. The aim of this study was to verify the possible neuroprotective effects of melatonin administration in hypermethioninemic pregnant rats on damage to biomolecules (Na+,K+‐ATPase, sulfhydryl content and DNA damage index) and behavior (open field, novel object recognition and water maze tasks), as well as its effect on cells morphology by electron microscopy in offspring. Wistar female rats received methionine (2.68 μmol/g body weight) and/or melatonin (10 mg/kg body weight) by subcutaneous injections during entire pregnancy. Control rats received saline. Biochemical analyzes were performed at 21 and 30 days of life of offspring and behavioral analyzes were performed only at 30 days of age in male pups. Results showed that gestational hypermethioninemia diminished Na+,K+‐ATPase activity and sulfhydryl content and increased DNA damage at 21 and 30 days of life. Melatonin was able to totally prevent Na+,K+‐ATPase activity alteration at 21 days and partially prevent its alteration at 30 days of rats life. Melatonin was unable in to prevent sulfhydryl and DNA damage at two ages. It also improved DNA damage, but not at level of saline animals (controls). Regarding to behavioral tests, data showed that pups exposed to gestational hypermethioninemia decreased reference memory in water maze, spent more time to the center of the open field and did not differentiate the objects in the recognition test. Melatonin was able to prevent the deficit in novel object recognition task. Electron microscopy revealed ultrastructure alterations in neurons of hypermethioninemic at both ages of offspring, whose were prevented by melatonin. These findings suggest that melatonin may be a good neuroprotective to minimize the harmful effects of gestational hypermethioninemia on offspring.
The Value of the Risk to Life in the Context of Crime
Authors: Picasso Emilio , Conte Grand Mariana
Published: August 2019

The value of the risk to life is a key element for benefit-cost analysis, enabling more rational public policy decisions in diverse areas as environmental, health, and crime. We value the risk to life in the context of crime using a discrete choice experiment (CE). The method has clear advantages in that it applies to the whole population and does not require vast data from labor markets, for example. Such data are not always available even in developed economies. Combining the stated preference approach with contingent valuation (CV), CE offer advantages yet to be explored in the context of crime. We demonstrate the application in a developing economy, where similar valuations are not available. The best estimate obtained for Argentina is an average of 1.5 million in 2015 US dollars per statistical life with a confidence interval ($1.1–$2.3). This result is consistent with estimates for the developed world, after appropriate transfer. We also analyze demographic factors in the risk to life, finding a positive influence of income, risk aversion, previous victimization experience and family size on the value of a statistical life, as well as a negative impact of individualism.
Dynamic Benefit-Cost Analysis for Uncertain Futures
Authors: Dudley Susan E. , Pérez Daniel R. , Mannix Brian F. , Carrigan Christopher
Published: August 2019

“Uncertain futures” refers to a set of policy problems that possess some combination of the following characteristics: (i) they potentially cause irreversible changes; (ii) they are widespread, so that policy responses may make sense only on a global scale; (iii) network effects are difficult to understand and may amplify (or moderate) consequences; (iv) time horizons are long; and (v) the likelihood of catastrophic outcomes is unknown or even unknowable. These characteristics tend to make uncertain futures intractable to market solutions because property rights are not clearly defined and essential information is unavailable. These same factors also pose challenges for benefit-cost analysis (BCA) and other traditional decision analysis tools. The diverse policy decisions confronting decision-makers today demand “dynamic BCA,” analytic frameworks that incorporate uncertainties and trade-offs across policy areas, recognizing that: perceptions of risks can be uninformed, misinformed, or inaccurate; risk characterization can suffer from ambiguity; and experts’ tendency to focus on one risk at a time may blind policymakers to important trade-offs. Dynamic BCA – which recognizes trade-offs, anticipates the need to learn from experience, and encourages learning – is essential for lowering the likelihoods and mitigating the consequences of uncertain futures while encouraging economic growth, reducing fragility, and increasing resilience.
From Football to Oil Rigs: Risk Assessment for Combined Cyber and Physical Attacks
Authors: Roberts Fred S.
Published: August 2019

Although cyber security has become widely recognized as a serious threat to our modern world, there are new threats to our security that combine cyber with other modes of “attack.” This article explores the increasingly important theme in homeland and national security that future attacks will be multimodal, in particular including both a cyber and a physical component, where the cyber attack is intended to make it easier to succeed in the physical attack, and is not an end in itself. The article describes sample scenarios of combined cyber and physical attacks in two sectors where even just cyber security efforts have lagged behind: sports stadiums and the maritime transportation system. It presents an approach to comparing the risk of a combined cyber followed by physical attack and that of a “traditional” physical attack on the same target. It then analyzes the different stadium and maritime examples from the point of view of this risk assessment approach.
Magnetic Source Imaging Localization of 14 and 6 Hz Positive Bursts
Authors: Jain Puneet , Ochi Ayako , Sharma Rohit , Otsubo Hiroshi
Published: August 2019

A 16-year-old boy with learning disability presented with nocturnal pharmaco-resistant focal seizures consisting of right arm/axilla pain, sometimes followed by tonic-clonic movements of right arm/leg since 8 years of age. He was on valproate and levetiracetam and had failed multiple drugs in the past. Family history and examination were unremarkable.
The role of mentors in addressing issues of work–life integration in an academic research environment
Authors: Durbin Dennis R. , House Stephanie C. , Meagher Emma A. , Rogers Jenna Griebel
Published: August 2019

Introduction:

There is growing evidence for both the need to manage work–life conflict and the opportunity for mentors to advise their mentees on how to do this in an academic research environment.

Methods:

A multiphase approach was used to develop and implement an evidence-informed training module to help mentors guide their mentees in issues of work–life conflict. Analysis of existing data from a randomized controlled trial (RCT) of a mentor training curriculum (n = 283 mentor/mentee dyads) informed the development of a work–life mentoring module which was incorporated into an established research mentor training curriculum and evaluated by faculty at a single academic medical center.

Results:

Only 39% of mentors and 36% of mentees in the RCT indicated high satisfaction with the balance between their personal and professional lives. The majority (75%) of mentors and mentees were sharing personal information as part of the mentoring relationship which was significantly associated with mentees’ ratings of the balance between their personal and professional lives. The effectiveness of the work–life module was assessed by 60 faculty mentors participating in a mentor training program at an academic medical center from 2013 to 2017. Among the respondents to the post-training survey, 82.5% indicated they were very/somewhat comfortable addressing work–life issues with their mentees as a result of the training, with significant improvements (p = 0.001) in self-assessments of mentoring skill in this domain.

Conclusions:

Our findings indicate that a structured training approach can significantly improve mentors’ self-reported skills in addressing work–life issues with their mentees.
Characterizing health researcher barriers to sharing results with study participants
Authors: McElfish Pearl A. , Long Christopher R. , James Laura P. , Scott Aaron J. , Flood-Grady Elizabeth , Kimminau Kim S. , Rhyne Robert L. , Burge Mark R. , Purvis Rachel S.
Published: August 2019

Introduction:

Research participants want to receive results from studies in which they participate. However, health researchers rarely share the results of their studies beyond scientific publication. Little is known about the barriers researchers face in returning study results to participants.

Methods:

Using a mixed-methods design, health researchers (N= 414) from more than 40 US universities were asked about barriers to providing results to participants. Respondents were recruited from universities with Clinical and Translational Science Award programs and Prevention Research Centers.

Results:

Respondents reported the percent of their research where they experienced each of the four barriers to disseminating results to participants: logistical/methodological, financial, systems, and regulatory. A fifth barrier, investigator capacity, emerged from data analysis. Training for research faculty and staff, promotion and tenure incentives, and funding agencies supporting dissemination of results to participants were solutions offered to overcoming barriers.

Conclusions:

Study findings add to literature on research dissemination by documenting health researchers’ perceived barriers to sharing study results with participants. Implications for policy and practice suggest that additional resources and training could help reduce dissemination barriers and increase the return of results to participants.
Validity and reliability of an online self-report 24-h dietary recall method (Intake24): a doubly labelled water study and repeated-measures analysis
Authors: Foster Emma , Lee Clement , Imamura Fumiaki , Hollidge Stefanie E. , Westgate Kate L. , Venables Michelle C. , Poliakov Ivan , Rowland Maisie K. , Osadchiy Timur , Bradley Jennifer C. , Simpson Emma L. , Adamson Ashley J. , Olivier Patrick , Wareham Nick , Forouhi Nita G. , Brage Soren
Published: August 2019

Online self-reported 24-h dietary recall systems promise increased feasibility of dietary assessment. Comparison against interviewer-led recalls established their convergent validity; however, reliability and criterion-validity information is lacking. The validity of energy intakes (EI) reported using Intake24, an online 24-h recall system, was assessed against concurrent measurement of total energy expenditure (TEE) using doubly labelled water in ninety-eight UK adults (40–65 years). Accuracy and precision of EI were assessed using correlation and Bland–Altman analysis. Test–retest reliability of energy and nutrient intakes was assessed using data from three further UK studies where participants (11–88 years) completed Intake24 at least four times; reliability was assessed using intra-class correlations (ICC). Compared with TEE, participants under-reported EI by 25 % (95 % limits of agreement −73 % to +68 %) in the first recall, 22 % (−61 % to +41 %) for average of first two, and 25 % (−60 % to +28 %) for first three recalls. Correlations between EI and TEE were 0·31 (first), 0·47 (first two) and 0·39 (first three recalls), respectively. ICC for a single recall was 0·35 for EI and ranged from 0·31 for Fe to 0·43 for non-milk extrinsic sugars (NMES). Considering pairs of recalls (first two v. third and fourth recalls), ICC was 0·52 for EI and ranged from 0·37 for fat to 0·63 for NMES. EI reported with Intake24 was moderately correlated with objectively measured TEE and underestimated on average to the same extent as seen with interviewer-led 24-h recalls and estimated weight food diaries. Online 24-h recall systems may offer low-cost, low-burden alternatives for collecting dietary information.