bluuebunny/crossref_metadata_2025 huggingface dataset:
High cell density cultivation of Escherichia coli DH5α in shake flasks with a new formulated medium
Authors: Ng Wenfa
Published: March 2018

High cell density cultivation necessitates cell division and biomass formation, the mechanisms of which remain poorly understood, especially from the cellular energetics perspective. Specifically, the sensing of energy abundance and the channelling of nutritional energy into biomass formation and cell maintenance remains enigmatic at the sensory, effector and decision levels. Thus, optimization of cell growth remains an iterative trial and error process where the principal parameters are growth medium composition and incubation temperature. In this study, a new semi-defined formulated medium was shown to be useful for high cell density cultivation of Escherichia coli DH5α (ATCC 53868). Comprising K2HPO4, 12.54; KH2PO4, 2.31; D-Glucose, 4.0; NH4Cl, 1.0; Yeast extract, 12.0; NaCl, 5.0; MgSO4, 0.24; the medium possessed a high capacity phosphate buffer able to moderate pH fluctuations during cell growth known to be detrimental to biomass formation. With glucose and NH4Cl providing the nutrients for initial growth, followed by a lag phase of 3 hours, a maximal optical density of 12.0 was obtained after 27 hours of cultivation at 37 oC and 230 rpm. Yeast extract provides a secondary source of carbon and nitrogen. Maximal optical density obtained in formulated medium was higher than the 10.1, 4.2, and 3.4 obtained in Tryptic Soy Broth, M9 with 1 g/L of yeast extract, and LB Lennox, respectively. Cultivation of E. coli DH5α in formulated medium with 6 g/L of glucose resulted in a longer lag phase of 8 hours and a longer time (68 hours) to attainment of maximal optical density, which marked the upper limit of glucose concentration beyond which biomass formation would be reduced. Specifically, glucose concentration above 6 g/L markedly reduced biomass formation possibly due to the environmental stress arising from low pH in the culture broth. Glucose concentration below 4 g/L, on the other hand, reduced biomass formation through a smaller pool of nutrients serving as biomass building blocks. Deviation from 1:1 molar ratio between glucose and NH4Cl was not detrimental to biomass formation and growth rates. Collectively, a semi-defined formulated medium could increase optical density of E. coli DH5α beyond that of LB Lennox and Tryptic Soy Broth, and may find use in cultivation of cells for applied microbiology research.
Timetable Design for Minimizing Passenger Travel Time and Congestion for a Single Metro Line
Authors: Shen Yi , Ren Gang , Liu Yang
Published: March 2018

This paper brings a proposal for a timetable optimization model for minimizing the passenger travel time and congestion for a single metro line under time-dependent demand. The model is an integer-programming model that systemically considers the passenger travel time, the capacity of trains, and the capacity of platforms. A multi-objective function and a recursive optimization method are presented to solve the optimization problem. Using the model we can obtain an efficient timetable with minimal passenger travel time and minimal number of congestion events on platforms. Moreover, by increasing the number of dispatches, the critical point from congestion state to free-flow state and the optimal timetable with minimal cost for avoiding congestion on platforms can be obtained. The effectiveness of the model is evaluated by a real example. A half-regular timetable with fixed headways in each operation period and an irregular timetable with unfixed headway are investigated for comparison.
Multiple Criteria Evaluation and the Inverse Hierarchy Model for Justifying the Choice of Rail Transport Mode
Authors: Sivilevičius Henrikas , Maskeliūnaitė Lijana
Published: March 2018

The choice of a particular mode of transport as an alternative to another one is subjective and usually based on an individual passenger’s approach to the evaluation of advantages and disadvantages of some particular means of transport. The paper presents the methods of analysing the reasons for passengers’ choice of travelling by train as an alternative to using air transport and the results obtained in the research. The 16 criteria (sub-criteria), describing the advantages of travelling by rail over air travel, are defined. The data of the survey questionnaire filled by 52 passengers of the Vilnius–Moscow train and the ranks assigned by them to the considered criteria are described. The average ranks of all 16 criteria and their normalized subjective weights are calculated by using a new method of average rank transformation into weight (ARTIW). The average ranks assigned by the passengers of the train to sub-criteria and the calculated global weights show what criteria are most important. Using the inverse hierarchy model based on the sub-criteria weights, the most and the least important groups of criteria are determined. The institutions and companies engaged in passenger transportation by rail, which give priority to improving the services described by the most important criteria, can make this mode of transport more attractive to people.
The Impact of Democratization and International Exposure to Indonesian Counter-Terrorism
Authors: Wibisono Ali Abdullah
Published: March 2018

Artikel ini menjelaskan tentang pengaruh dari perhatian dunia internasional – diwakili oleh Amerika Serikat – terhadap kebijakan Indonesia merespon terorisme di era reformasi. Dua aspek utama dalam kontra-terorisme menjadi pembatas dari perhatian internasional ini, yaitu aspek efektivitas kontra-terorisme dan aspek kepatuhan kepada nilai-nilai Hak Asasi Manusia (HAM). Karena kebutuhannya untuk melakukan sekuritisasi terhadap isu terorisme terjadi pada era demokrasi, pemerintah Indonesia harus mengadopsi nilai-nilai HAM dalam meyakini public dan dunia internasional. Tetapi penggunaan nilai HAM tidak dilakukan untuk memastikan terjaganya pemenuhan HAM, melainkan untuk menjustifikasikan tindakan-tindakan eksepsional dalam kontra-terorisme. Selanjutnya kerjasama dengan Amerika Serikat memfasilitasi terjadinya penguatan kapabilitas koersif kontra-terorisme dalam wujud lembaga criminal justice system yang berkapasitas khusus dalam bidang ini. Ketiadaan tekanan untuk secara serius mempertimbangkan perlindungan HAM dalam kontra-terorisme merupakan salah satu contributor dari rendahnya manifestasi institusional dari kontra-terorisme Indonesia yang ditandai dengan ketiadaan dokumen formal yang secara eksplisit mengartikulasikan strategi (tujuan, ukuran pencapaian dan instrument) kontra-terorisme sehingga kebijakan kontra-terorisme Indonesia pun absen akan evaluasi. Sementara itu bantuan langsung kepada kepolisian dan militer Indonesia juga membuat pemerintah – eksekutif maupun legislative – memberikan otoritas eksepsional kepada aparat keamanan tanpa mekanisme akuntabilitas dalam pelaksanaannya.
Evolusi Konsep Keamanan Energi
Authors: Ramadhani Arshie
Published: March 2018

Konsep keamanan energi bersifat kontekstual dan dapat memiliki makna yang berbeda dalam konteks yang berbeda. Terkait dengan hal tersebut, tulisan ini berusaha mengkaji perkembangan literatur mengenai konsep keamanan energi dari waktu ke waktu. Tulisan ini kemudian akan mengelompokkan literatur-literatur tersebut dengan menggunakan metode kronologi ke dalam tiga periode berbeda, yaitu periode 1970-1990, periode 2000-2010 dan periode pasca 2010. Dari pengelompokkan tersebut, terlihat bahwa terjadi perluasan tema dalam definisi konsep keamanan energi yang awalnya terkait dengan tema ketersediaan dan harga menjadi mencakup tema infrastruktur, lingkungan, dampak sosial, efisiensi, tata kelola dan kebijakan publik, dan sebagainya. Hal ini kemudian menimbulkan perdebatan mengenai apakah konsep keamanan energi perlu diperluas untuk mengakomodasi munculnya tantangan-tantangan baru atau tetap dibatasi agar keamanan tidak kehilangan maknanya. Penulis berargumen bahwa pendefinisan keamanan energi harus tetap dilekatkan dengan definisi keamanan, “survival in the face of existential threat,”agar konsep keamanan itu sendiri tidak kehilangan fokusnya. Dengan menggunakan perspektif kontekstual dan variasi konseptual dari waktu ke waktu, tulisan ini diharapkan dapat menghadirkan perdebatan teoretis mengenai bagaimana isu energi dapat menjadi isu keamanan serta memberikan kontribusi berupa pemetaan konsep keamanan energi sebagai referensi untuk pengambilan kebijakan energi.
Strategi Politik Elektoral Gerakan Buruh Di Korea Selatan (2004-2014)
Authors: Pratiwi Dana
Published: March 2018

Penelitian ini menganalisis penyebab strategi politik elektoral gerakan buruh di Korea Selatan pasca tahun 2004 cenderung tidak efektif. Hal ini dapat dilihat dengan menurunnya jumlah perolehan kursi oleh partai buruh di parlemen nasional, terjadi faksi-faksi dalam internal partai, renggangnya hubungan antara organisasi gerakan buruh dengan partai, partai tidak mampu memperluas basis dukungan dan juga belum mampu mengakomodir isu-isu kebijakan nasional lainnya. Dalam menjawab pertanyaan penelitian tersebut, penulis menggunakan metode kualitatif dan mengacu pada sumber data-data sekunder. Analisis penelitian ini merujuk pada studi yang dilakukan oleh Collins. Menurutnya, terdapat dua aspek yang menentukan sebuah gerakan agar dapat membentuk partai politik yang berhasil dalam politik elektoral. Kedua aspek tersebut yaitu kesempatan politik dan mobilisasi sumber daya yang dilakukan oleh gerakan. Penulis berpendapat bahwa penyebab tidak efektifnya strategi elektoral gerakan buruh di Korea Selatan pasca tahun 2004 adalah adanya hambatan dalam kesempatan politik yang belum menguntungkan bagi gerakan buruh dan dalam mobilisasi sumber daya.
BANHEIRO REQUEER: PROTOCOLO TEATRAL VERBO-VISUAL EM DISCURSO
Authors: Gonçalves Jean Carlos , Araújo Reinaldo Kovalski
Published: March 2018

O artigo trata de uma experiência de formação vivenciada em um grupo de pesquisa no ano de 2013 na Faculdade de Artes do Paraná. O projeto envolveu dez professoras acadêmicas e egressas do curso de Licenciatura em Teatro, e teve por objetivo a montagem de um espetáculo que abordasse as discussões sobre gênero, corpo e identidades, mediadas pelo teatro educação. As narrativas das professoras participantes desse grupo compõem o corpus de uma pesquisa de mestrado, que teve a análise do discurso (AD) na produção de sentidos sobre corpo e identidades a partir de protocolos teatrais confeccionados pelas participantes do projeto.
QUEBRANDO TABUS SOBRE OS JOGOS TEATRAIS DE VIOLA SPOLIN
Authors: Ramaldes Karine
Published: March 2018

Neste estudo abordo alguns pontos significativos da metodologia improvisacional dos jogos teatrais de Viola Spolin, a fim de elucidar a relevância de tal metodologia para os diversos fazedores de teatro, tanto os iniciantes como os iniciados. O objetivo é esclarecer que esta metodologia não se refere apenas à iniciação teatral, mas também a preparação do ator no curso de sua profissão. Parto de conceitos utilizados especialmente por Viola Spolin, Ingrid Dormien Koudela e Antônio Januzelli.
A COMÉDIA COMO ESPELHO: THOMAS RANDOLPH E A RECEPÇÃO ELISABETANA DO TEATRO ANTIGO
Authors: Torres Milton Luiz
Published: March 2018

O artigo trata da recepção do antigo drama grego, especialmente a comédia, na Inglaterra elizabetana, durante a assim-chamada controvérsia antiteatral. Para isso, o artigo analisa efeitos dessa controvérsia na peça O espelho das musas, escrita por Thomas Randolph com base na Ética a Nicômaco de Aristóteles, e que recupera a tradição clássica do espelho para apresentar a função formadora da comédia.
Nonlinear Electrostatic Steepening of Whistler Waves: The Guiding Factors and Dynamics in Inhomogeneous Systems
Authors: Agapitov O. , Drake J. F. , Vasko I. , Mozer F. S. , Artemyev A. , Krasnoselskikh V. , Angelopoulos V. , Wygant J. , Reeves G. D.
Published: March 2018

Whistler mode chorus waves are particularly important in outer radiation belt dynamics due to their key role in controlling the acceleration and scattering of electrons over a very wide energy range. The efficiency of wave‐particle resonant interactions is defined by whistler wave properties which have been described by the approximation of plane linear waves propagating through the cold plasma of the inner magnetosphere. However, recent observations of extremely high‐amplitude whistlers suggest the importance of nonlinear wave‐particle interactions for the dynamics of the outer radiation belt. Oblique chorus waves observed in the inner magnetosphere often exhibit drastically nonsinusoidal (with significant power in the higher harmonics) waveforms of the parallel electric field, presumably due to the feedback from hot resonant electrons. We have considered the nature and properties of such nonlinear whistler waves observed by the Van Allen Probes and Time History of Events and Macroscale Interactions define during Substorms in the inner magnetosphere, and we show that the significant enhancement of the wave electrostatic component can result from whistler wave coupling with the beam‐driven electrostatic mode through the resonant interaction with hot electron beams. Being modulated by a whistler wave, the electron beam generates a driven electrostatic mode significantly enhancing the parallel electric field of the initial whistler wave. We confirm this mechanism using a self‐consistent particle‐in‐cell simulation. The nonlinear electrostatic component manifests properties of the beam‐driven electron acoustic mode and can be responsible for effective electron acceleration in the inhomogeneous magnetic field.
Faster Traveling Atmosphere Disturbances Caused by Polar Ionosphere Turbulence Heating
Authors: Liu Jing , Wang Wenbin , Burns Alan , Oppenheim Meers , Dimant Yakov
Published: March 2018

A new module, which includes both the turbulence electron heating and the electron‐neutral cooling rate correction associated with the Farley‐Buneman onstability (FBI) in the National Center for Atmospheric Research‐Thermosphere Ionosphere Electrodynamics Global Circulation Model, enables us, for the first time, to investigate the intimate coupling between polar turbulence electron heating and thermosphere disturbances in the context of a first‐principle, self‐consistent model. Our simulation results show that during geomagnetic storms, after taking the FBI effects into account, Joule heating is almost doubled in the E region at these locations of strong convection electric field. This increases (~6%) the phase speed of traveling atmosphere disturbances at around 400 km that are launched from both hemispheres. Additional heating sources also directly produce a divergence in the zonal wind with magnitudes of 20 m/s in the lower thermosphere. However, the FBI impact on the thermosphere at F region altitudes is not so straightforward. E region anomalous electron heating in association with the FBI can change the phase speeds and magnitudes of traveling atmosphere disturbances from high latitudes in both hemispheres and consequently modify global neutral wind circulation at F region altitudes. This, in turn, can affect the neutral temperature through adiabatic compressional heating and expansive cooling by about 40 K. This study demonstrates how the ionosphere‐thermosphere physical processes across different temporal and spatial scales are tightly coupled together throughout the whole upper atmosphere domain.
A Study of Observations of Ionospheric Upwelling Made by the EISCAT Svalbard Radar During the International Polar Year Campaign of 2007
Authors: David T. W. , Wright D. M. , Milan S. E. , Cowley S. W. H. , Davies J. A. , McCrea I.
Published: March 2018

We have used EISCAT Svalbard Radar data, obtained during the International Polar Year 2007 campaign, to study ionospheric upflow events with fluxes exceeding 1013 m−2 s−1. In this study, we have classified the upflow events into low, medium, and high flux upflows, and we report on the incidence and seasonal distribution of these different classes. It is observed that high upflow fluxes are comparatively rare and low flux upflow events are a frequent phenomenon. Analysis shows that occurrence peaks around local noon at 31%, 16%, and 2% for low, medium, and high‐flux upflow, respectively, during geomagnetically disturbed periods. In agreement with previous studies on vertical and field‐aligned flows, ion upflow is observed to take place over a wide range of geomagnetic conditions, with downflow flux occurrence being lower than upflow occurrence. In contrast to previous observations, however, the upflow occurrence is greater around noon during highly disturbed geomagnetic conditions than for moderate geomagnetic conditions. Analysis of the seasonal distribution reveals that, while high‐flux upflow has its peak around local noon in the summer, with its occurrence being driven predominantly by high geomagnetic disturbance, the occurrence of low‐flux upflow is broadly distributed across all seasons, geomagnetic activity conditions, and times of day. The medium‐flux upflow events, although distributed across all seasons, show an occurrence peak strongly related to high Kp. Furthermore, during highly disturbed conditions, the low‐flux and medium‐flux upflow events show a minimum occurrence during the winter, whereas minimum occurrence for the high‐flux upflow events occurs in autumn.
Assessment of the Impact of FORMOSAT‐7/COSMIC‐2 GNSS RO Observations on Midlatitude and Low‐Latitude Ionosphere Specification: Observing System Simulation Experiments Using Ensemble Square Root Filter
Authors: Hsu C.‐T. , Matsuo T. , Yue X. , Fang T.‐W. , Fuller‐Rowell T. , Ide K. , Liu J.‐Y.
Published: March 2018

The Formosa Satellite‐7/Constellation Observing System for Meteorology, Ionosphere, and Climate‐2 (FORMOSAT‐7/COSMIC‐2) Global Navigation Satellite System radio occultation (RO) payload can provide global observations of slant total electron content (sTEC) with an unprecedentedly high spatial temporal resolution. Recently, a new ionospheric data assimilation system, the Community Gridpoint Statistical Interpolation (GSI) Ionosphere, is constructed with the National Oceanic and Atmospheric Administration GSI Ensemble Square Root Filter and the Global Ionosphere Plasmasphere and the Thermosphere Ionosphere Electrodynamic General Circulation Model. The paper demonstrates the capability of the GSI Ionosphere to improve the ionospheric specification and make a quantitative assessment of the impact of FORMOSAT‐7/COSMIC‐2 RO data on the ionospheric observing system simulation experiments conducted to calibrate key Ensemble Square Root Filter parameters that control detrimental effects of the sampling errors, particularly on the ensemble‐based estimation of the correlation between observations and model states, in order to yield high‐quality assimilation analysis. Results from the observing system simulation experiments show that (1) an ensemble size larger than 70 is recommended for assimilation of RO sTEC data with the GSI Ionosphere and (2) localizing the impact of observations around the tangent points in the horizontal direction with a length scale of 5,000 km is effective in improving assimilation analysis quality. Assimilation of sTEC data from FORMOSAT‐7/COSMIC‐2 can considerably improve the global ionospheric specification through the application of the GSI Ionosphere. The GSI Ionosphere can provide instantaneous global pictures of the ionosphere variability and help characterize day‐to‐day variability of the ionosphere and deepen our understanding of the observed day‐to‐day variability.
Quantitative Evaluation of Radial Diffusion and Local Acceleration Processes During GEM Challenge Events
Authors: Ma Q. , Li W. , Bortnik J. , Thorne R. M. , Chu X. , Ozeke L. G. , Reeves G. D. , Kletzing C. A. , Kurth W. S. , Hospodarsky G. B. , Engebretson M. J. , Spence H. E. , Baker D. N. , Blake J. B. , Fennell J. F. , Claudepierre S. G.
Published: March 2018

We simulate the radiation belt electron flux enhancements during selected Geospace Environment Modeling (GEM) challenge events to quantitatively compare the major processes involved in relativistic electron acceleration under different conditions. Van Allen Probes observed significant electron flux enhancement during both the storm time of 17–18 March 2013 and non–storm time of 19–20 September 2013, but the distributions of plasma waves and energetic electrons for the two events were dramatically different. During 17–18 March 2013, the SYM‐H minimum reached −130 nT, intense chorus waves (peak Bw ~140 pT) occurred at 3.5 < L < 5.5, and several hundred keV to several MeV electron fluxes increased by ~2 orders of magnitude mostly at 3.5 < L < 5.5. During 19–20 September 2013, the SYM‐H remained higher than −30 nT, modestly intense chorus waves (peak Bw ~80 pT) occurred at L > 5.5, and electron fluxes at energies up to 3 MeV increased by a factor of ~5 at L > 5.5. The two electron flux enhancement events were simulated using the available wave distribution and diffusion coefficients from the GEM focus group Quantitative Assessment of Radiation Belt Modeling. By comparing the individual roles of local electron heating and radial transport, our simulation indicates that resonant interaction with chorus waves is the dominant process that accounts for the electron flux enhancement during the storm time event particularly near the flux peak locations, while radial diffusion by ultralow‐frequency waves plays a dominant role in the enhancement during the non–storm time event. Incorporation of both processes reasonably reproduces the observed location and magnitude of electron flux enhancement.
Seismicity During Continental Breakup in the Red Sea Rift of Northern Afar
Authors: Illsley‐Kemp Finnigan , Keir Derek , Bull Jonathan M. , Gernon Thomas M. , Ebinger Cynthia , Ayele Atalay , Hammond James O. S. , Kendall J.‐Michael , Goitom Berhe , Belachew Manahloh
Published: March 2018

Continental rifting is a fundamental component of plate tectonics. Recent studies have highlighted the importance of magmatic activity in accommodating extension during late‐stage rifting, yet the mechanisms by which crustal thinning occurs are less clear. The Red Sea rift in Northern Afar presents an opportunity to study the final stages of continental rifting as these active processes are exposed subaerially. Between February 2011 and February 2013 two seismic networks were installed in Ethiopia and Eritrea. We locate 4,951 earthquakes, classify them by frequency content, and calculate 31 focal mechanisms. Results show that seismicity is focused at the rift axis and the western marginal graben. Rift axis seismicity accounts for ∼64% of the seismic moment release and exhibits a swarm‐like behavior. In contrast, seismicity at the marginal graben is characterized by high‐frequency earthquakes that occur at a constant rate. Results suggest that the rift axis remains the primary locus of seismicity. Low‐frequency earthquakes, indicative of magmatic activity, highlight the presence of a magma complex ∼12 km beneath Alu‐Dalafilla at the rift axis. Seismicity at the marginal graben predominantly occurs on westward dipping, antithetic faults. Focal mechanisms show that this seismicity is accommodating E‐W extension. We suggest that the seismic activity at the marginal graben is either caused by upper crustal faulting accommodating enhanced crustal thinning beneath Northern Afar or as a result of flexural faulting between the rift and plateau. This seismicity is occurring in conjunction with magmatic extension at the rift axis, which accommodates the majority of long‐term extension.
The Challenge of Identifying Controls on Cloud Properties and Precipitation Onset for Cumulus Congestus Sampled During MC3E
Authors: Mechem David B. , Giangrande Scott E.
Published: March 2018

Controls on precipitation onset and the transition from shallow cumulus to congestus are explored using a suite of 16 large‐eddy simulations based on the 25 May 2011 event from the Midlatitude Continental Convective Clouds Experiment (MC3E). The thermodynamic variables in the model are relaxed at various timescales to observationally constrained temperature and moisture profiles in order to better reproduce the observed behavior of precipitation onset and total precipitation. Three of the simulations stand out as best matching the precipitation observations and also perform well for independent comparisons of cloud fraction, precipitation area fraction, and evolution of cloud top occurrence. All three simulations exhibit a destabilization over time, which leads to a transition to deeper clouds, but the evolution of traditional stability metrics by themselves is not able to explain differences in the simulations. Conditionally sampled cloud properties (in particular, mean cloud buoyancy), however, do elicit differences among the simulations. The inability of environmental profiles alone to discern subtle differences among the simulations and the usefulness of conditionally sampled model quantities argue for hybrid observational/modeling approaches. These combined approaches enable a more complete physical understanding of cloud systems by combining observational sampling of time‐varying three‐dimensional meteorological quantities and cloud properties, along with detailed representation of cloud microphysical and dynamical processes from numerical models.
Winter Precipitation Efficiency of Mountain Ranges in the Colorado Rockies Under Climate Change
Authors: Eidhammer Trude , Grubišić Vanda , Rasmussen Roy , Ikdea Kyoko
Published: March 2018

Orographic precipitation depends on the environmental conditions and the barrier shape. In this study we examine the sensitivity of the precipitation efficiency (i.e., drying ratio (DR)), defined as the ratio of precipitation to incoming water flux, to mountain shape, temperature, stability, and horizontal velocity of the incoming air mass. Furthermore, we explore how the DR of Colorado mountain ranges might change under warmer and moister conditions in the future. For given environmental conditions, we find the DR to be primarily dependent on the upwind slope for mountain ranges wider than about 70 km and on both the slope and width for narrower ranges. Temperature is found to exert an influence on the DR for all Colorado mountain ranges, with DR decreasing with increasing temperature, under both the current and future climate conditions. The decrease of DR with temperature under warmer climate was found to be stronger for wider mountains than the narrower ones. We attribute this asymmetry to the sensitivity of DR to reduced horizontal velocity under warmer conditions. Specifically, while DR for wider mountains shows no sensitivity to changes in horizontal velocity, the DR for narrow ranges increases as the horizontal velocity decreases and more time is provided for precipitation to form. Thus, for narrower ranges, the horizontal velocity appears to offset the temperature effect slightly. The percentagewise decrease of DR for all examined mountain ranges is about 4%K−1. In comparison, the increase in precipitation is about 6%K−1 while the vapor flux increase is about 9%K−1.
HCN Production via Impact Ejecta Reentry During the Late Heavy Bombardment
Authors: Parkos Devon , Pikus Aaron , Alexeenko Alina , Melosh H. Jay
Published: March 2018

Major impact events have shaped the Earth as we know it. The Late Heavy Bombardment is of particular interest because it immediately precedes the first evidence of life. The reentry of impact ejecta creates numerous chemical by‐products, including biotic precursors such as HCN. This work examines the production of HCN during the Late Heavy Bombardment in more detail. We stochastically simulate the range of impacts on the early Earth and use models developed from existing studies to predict the corresponding ejecta properties. Using multiphase flow methods and finite‐rate equilibrium chemistry, we then find the HCN production due to the resulting atmospheric heating. We use Direct Simulation Monte Carlo to develop a correction factor to account for increased yields due to thermochemical nonequilibrium. We then model 1‐D atmospheric turbulent diffusion to find the time accurate transport of HCN to lower altitudes and ultimately surface water. Existing works estimate the necessary HCN molarity threshold to promote polymerization that is 0.01 M. For a mixing depth of 100 m, we find that the Late Heavy Bombardment will produce at least one impact event above this threshold with probability 24.1% for an oxidized atmosphere and 56.3% for a partially reduced atmosphere. For a mixing depth of 10 m, the probability is 79.5% for an oxidized atmosphere and 96.9% for a partially reduced atmosphere. Therefore, Late Heavy Bombardment impact ejecta is likely an HCN source sufficient for polymerization in shallow bodies of water, particularly if the atmosphere were in a partially reduced state.
A New Coupled Ocean‐Waves‐Atmosphere Model Designed for Tropical Storm Studies: Example of Tropical Cyclone Bejisa (2013–2014) in the South‐West Indian Ocean
Authors: Pianezze J. , Barthe C. , Bielli S. , Tulet P. , Jullien S. , Cambon G. , Bousquet O. , Claeys M. , Cordier E.
Published: March 2018

Ocean‐Waves‐Atmosphere (OWA) exchanges are not well represented in current Numerical Weather Prediction (NWP) systems, which can lead to large uncertainties in tropical cyclone track and intensity forecasts. In order to explore and better understand the impact of OWA interactions on tropical cyclone modeling, a fully coupled OWA system based on the atmospheric model Meso‐NH, the oceanic model CROCO, and the wave model WW3 and called MSWC was designed and applied to the case of tropical cyclone Bejisa (2013–2014). The fully coupled OWA simulation shows good agreement with the literature and available observations. In particular, simulated significant wave height is within 30 cm of measurements made with buoys and altimeters. Short‐term (< 2 days) sensitivity experiments used to highlight the effect of oceanic waves coupling show limited impact on the track, the intensity evolution, and the turbulent surface fluxes of the tropical cyclone. However, it is also shown that using a fully coupled OWA system is essential to obtain consistent sea salt emissions. Spatial and temporal coherence of the sea state with the 10 m wind speed are necessary to produce sea salt aerosol emissions in the right place (in the eyewall of the tropical cyclone) and with the right size distribution, which is critical for cloud microphysics.
VHF Radar Images of Artificial Field‐Aligned Ionospheric Irregularities in the Subauroral E Region
Authors: Hysell D. L. , Munk J. , McCarrick M.
Published: March 2018

Artificial E region field‐aligned plasma density irregularities (AFAIs) have been generated using the High‐frequency Active Auroral Research Program (HAARP) ionospheric modification facility in Gakona and observed with a 30 MHz coherent scatter radar imager in Homer, Alaska. The AFAIs were generated using a distinctive, twisted‐beam antenna pattern that illuminated a particularly broad volume overhead. The broad beam facilitates studies of natural sporadic E layer patches when they are present. The center of the pattern was pointed at different angles between zenith and magnetic zenith to examine the effects on the AFAI morphology. Radar images of AFAIs generally resemble the radiation pattern of the high‐frequency source, but the irregularities are strongest within a narrow range of zenith angles bounded approximately by the Spitze angle. A number of factors which might influence AFAI generation and detection are examined. The most important is most likely the requirement for the pump mode to have a standing‐wave component for thermal parametric instability to operate.
H
alosiccatus
Authors: Amoozegar Mohammad Ali , Ventosa Antonio
Published: March 2018

Ha.lo.sic.ca'tus. Gr. n.
hals halos
, salt; L. adj.
siccatus
, dried‐up; N.L. masc. n.
Halosiccatus
, organism from dried salt.

Euryarchaeota / Halobacteria / Halobacteriales / Halobacteriaceae / Halosiccatus

The genus
Halosiccatus
is classified within the family
Halobacteriaceae
, order
Halobacteriales
, in the class
Halobacteria
. The cells are pleomorphic, from tiny rods to triangles or disk‐shaped, and Gram‐stain‐negative. Colonies are pale orange pigmented. They are obligate aerobes and extreme halophiles. At least 2.5 M NaCl and 0.02 M MgCl
2
are required for growth. The cells are growing over the pH range and the temperature range 7.0–8.5 and 25–55°C, respectively. Polar lipids include phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, phosphatidic acid, three unidentified glycolipids, and one unidentified phospholipid. The respiratory lipoquinone present is MK‐8 (II‐H
2
). The genus
Halosiccatus
is most closely related to the genera
Halomicrobium
,
Halosimplex
, and
Halorientalis
according to the phylogenetic analysis of 16S rRNA gene and four housekeeping genes. Currently, the genus consists of one species,
Halosiccatus urmianus
, which is the type species of the genus and has been isolated from brine sample of the Urmia hypersaline lake in Iran.

DNA G + C content (mol%)
: 68.1 (HPLC).

Type species
:
Halosiccatus urmianus
Mehrshad, Amoozegar, Makhdoumi, Shahzadeh Fazeli, Farahani, Asadi, Schumann and Ventosa 2016, 729
VP
.
Integration processes during frequency graph comprehension: Performance and eye movements while processing tree maps versus pie charts
Authors: Huestegge Lynn , Pötzsch Tristan Herbert
Published: March 2018

Frequency graph types differ in the way how data are translated into visual representations. We compared 2 visualization methods, a traditional circular representation (pie chart) and a rectangular representation (constant column width tree map), which were hypothesized to differ regarding the cognitive ease of visual comparison processes. Performance was evaluated in tasks involving proportion and comparison judgments under both highly controlled and more realistic circumstances. The results showed performance benefits (in terms of reduced response times or error rates) for rectangular representations. Additional eye movement analyses revealed that this benefit was mainly due to a facilitation of scanning the graph for relevant information. The results suggest that facilitating comparison processes by representing the critical variable in less complex visual dimensions (i.e., straight length with constant orientation instead of surface area or curved length) eventually enhances the efficiency of integration processes during graph comprehension.
Effect of Pulse Duration on Corrosion and Impression Creep Properties of AA5083‐H111 Al–Mg Alloy Weldments Processed by P‐GTAW
Authors: Umar­ Mustafa , Sathiya Paulraj
Published: March 2018

In this work, the corrosion and impression creep properties of weldments are determined using potentiodynamic polarization test and impression creep test. It is evident that the shorter pulse duration results in comparatively finer grains and reduces the loss of magnesium in fusion zone, which facilitates an increase in precipitation of anodic β‐phase (Al3Mg2) and Mg2Si particles in the grain boundaries. It leads to the formation of pits by dissolving Mg atoms and propagate along the interdendritic region and finally corrode the surface thoroughly. On contrary, the increase in pulse duration results in uniform distribution of iron‐rich Al6(Fe,Mn) intermetallics as well as Fe and Mn particles in the interdendritic region which induce localized cathodic reaction and these localized cathodes assisted in achieving noble corrosion resistance by increasing the width of passive region. Also, an increase in creep resistance is attained with an increase in activation energy at a temperature of 573 K owing to the uniform dispersion of iron‐rich Al6(Fe,Mn) intermetallics in the grain boundaries of weldments processed with longer pulse duration. Hence, it is inferred from this research that the rise in pulse duration improves the corrosion and creep resistance of weldments by altering the morphology and surface distribution of intermetallics.
Unique Shape Memory Elastomer Associated with Reversible Sacrificial Hydrogen Bonds: Tough and Flexible When below Its Tg
Authors: Lin Tengfei , Li Siyuan , Ke Jinhuang , Zheng Yuying , Yu Yan
Published: March 2018

Thermally induced shape memory polymers (SMPs) are fragile and brittle when cooling to a low temperature to generate temporary shapes. In the present study, the authors implement a new design strategy for fabricating elastomeric SMPs with low‐temperature flexibility by engineering reversible sacrificial hydrogen bonds into a chemically crosslinked network. Compatible, amorphous, hindered phenol moieties (Irganox 1010) are incorporated into epoxidized natural rubber (ENR) and the ENR composites are cured with zinc diacrylate (ZDA). Such reversible sacrificial bonds can rupture prior to the rupture of the bonds of the crosslinked network during stretching, which will dissipate energy and facilitate reorientation of the rubber chains. Based on the functional mechanisms, ENR composites exhibit unusual toughness and flexibility and can undergo large deformations even when below their Tg. Irganox 1010 can also be used to tune the glass transition temperature (Tg) and improve the chain mobility of the elastomer sample by providing sufficient intermolecular hydrogen bonding interactions. ENR composites demonstrate thermally triggered shape memory performance. Moreover, the dissociation/reformation of hydrogen bonds upon stretching/cooling can endow the elastomer sample with unique reversible plastics shape memory (RPSM) performance. These SMPs possess excellent shape fixity and recovery.
Tuning the Molecular Weight of the Electron Accepting Polymer in All‐Polymer Solar Cells: Impact on Morphology and Charge Generation
Authors: Deshmukh Kedar D. , Matsidik Rukiya , Prasad Shyamal K. K. , Connal Luke A. , Liu Amelia C. Y. , Gann Eliot , Thomsen Lars , Hodgkiss Justin M. , Sommer Michael , McNeill Christopher R.
Published: March 2018

Molecular weight is an important factor determining the morphology and performance of all‐polymer solar cells. Through the application of direct arylation polycondention, a series of batches of a fluorinated naphthalene diimide‐based acceptor polymer are prepared with molecular weight varying from Mn = 20 to 167 kDa. Used in conjunction with a common low bandgap donor polymer, the effect of acceptor molecular weight on solar cell performance, morphology, charge generation, and transport is explored. Increasing the molecular weight of the acceptor from Mn = 20 to 87 kDa is found to increase cell efficiency from 2.3% to 5.4% due to improved charge separation and transport. Further increasing the molecular weight to Mn = 167 kDa however is found to produce a drop in performance to 3% due to liquid–liquid phase separation which produces coarse domains, poor charge generation, and collection. In addition to device studies, a systematic investigation of the microstructure and photophysics of this system is presented using a combination of transmission electron microscopy, grazing‐incidence wide‐angle X‐ray scattering, near‐edge X‐ray absorption fine‐structure spectroscopy, photoluminescence quenching, and transient absorption spectroscopy to provide a comprehensive understanding of the interplay between morphology, photophysics, and photovoltaic performance.
Polyampholyte Hydrogels with pH Modulated Shape Memory and Spontaneous Actuation
Authors: Zhang Yuancheng , Liao Jiexin , Wang Tao , Sun Weixiang , Tong Zhen
Published: March 2018

Polyampholyte hydrogels are synthesized by one‐step copolymerization of cationic monomer 3‐(methacryloylamino)propyltrimethylammonium chloride, anionic monomers sodium p‐styrenesulfonate (NaSS), and methacrylic acid (MAA) without chemical crosslinker and adding salts. The hydrogels exhibit pH responsive shape memory behavior; the temporary shape of the hydrogel is formed manually after immersing in NaOH solution and fixed in HCl solution, while the shape recovery occurs by immersing in NaOH again. Most interestingly, the hydrogel shows a spontaneous shape change after the first shape memory cycle. When the recovered hydrogel with a little residual deformation is immersed in HCl again, it twists spontaneously and rapidly to the previous temporary shape. The spontaneous twisting and recovering can be repeated for ten times. Furthermore, the hydrogel swells quickly and is strengthened in HCl, while shrinks and weakens in NaOH during the shape change procedure. This unique synergistic effect of fast swelling, residual helical deformation, and increased strength plays a significant role in the spontaneous shape alternation. This new finding will initiate a new prosperous design for new soft actuators requiring successive actions.
Tumor Cells‐Selective Bionic Nanodevice Exploiting Heparanase Combats Metastatic Breast Cancer
Authors: Lang Tianqun , Ran Wei , Dong Xinyue , Zheng Zhong , Liu Yiran , Yin Qi , Li Yaping
Published: March 2018

The clinical application of the cytotoxic chemotherapeutic agents in the treatment of metastatic breast cancer is limited by their poor selectivity to cancer cells. In this work, a bionic nanodevice consisting of the docetaxel (DTX)‐heparan sulfate (HS) conjugate (HS‐DTX) micelle with a red blood cells membrane (RBC) coating on its surface, termed as rHS‐DTX, is first constructed. It is found that the cytotoxicity of DTX is concealed by HS in human mammary epithelial Michigan Cancer Foundation (MCF)‐10A cells but restored in human mammary cancer MCF‐7 cells because HS is hydrolyzed by heparanase (Hpa), which is overexpressed only in MCF‐7 but not MCF‐10A cells. The RBC coating enhances the cellular uptake of HS‐DTX and endows it with the long circulating ability in blood. In the MCF‐7 metastatic breast cancer mice model, rHS‐DTX exhibits 6.35‐fold higher intratumor DTX accumulation than the free DTX injection and achieves a tumor inhibiting rate of 98.2% and a lung metastasis suppression rate of 99.6%. No severe toxicity is observed in the major organs and blood of mice treated with rHS‐DTX. In summary, rHS‐DTX can provide a promising strategy for targeting therapy of metastatic breast cancer by improving the tumor‐suppressing efficacy of DTX.
Simultaneously Excited Downshifting/Upconversion Luminescence from Lanthanide‐Doped Core/Shell Fluoride Nanoparticles for Multimode Anticounterfeiting
Authors: Liu Jing , Rijckaert Hannes , Zeng Min , Haustraete Katrien , Laforce Brecht , Vincze Laszlo , Van Driessche Isabel , Kaczmarek Anna M. , Van Deun Rik
Published: March 2018

This work presents a novel anticounterfeiting strategy based on a material changing its emission color in response to a change in the excitation sources—where a single ultraviolet (UV) or near‐infrared (NIR) light source are employed or simultaneously using two excitation sources (xenon lamp and NIR laser). Following this approach, various combinations of lanthanide (Ln3+)‐doped LiLuF4/LiYF4 core/shell nanoparticles are prepared, providing a promising route to design flexible nanomaterials, as well as already a small library of luminescent materials, which change color when varying the excitation source (UV, NIR or both UV and NIR). Aside from excitation source‐dependent color change, these materials additionally show excitation‐source power‐dependent color change. This work exploits the possibility of developing a new class of multimode anticounterfeit nanomaterials, with excellent performance, which would be almost impossible to mimic or replicate, providing a very high level of security.
Kinetics of Decelerated Melting
Authors: Wondraczek Lothar , Pan Zhiwen , Palenta Theresia , Erlebach Andreas , Misture Scott T. , Sierka Marek , Micoulaut Matthieu , Hoppe Uwe , Deubener Joachim , Greaves G. Neville
Published: March 2018

Melting presents one of the most prominent phenomena in condensed matter science. Its microscopic understanding, however, is still fragmented, ranging from simplistic theory to the observation of melting point depressions. Here, a multimethod experimental approach is combined with computational simulation to study the microscopic mechanism of melting between these two extremes. Crystalline structures are exploited in which melting occurs into a metastable liquid close to its glass transition temperature. The associated sluggish dynamics concur with real‐time observation of homogeneous melting. In‐depth information on the structural signature is obtained from various independent spectroscopic and scattering methods, revealing a step‐wise nature of the transition before reaching the liquid state. A kinetic model is derived in which the first reaction step is promoted by local instability events, and the second is driven by diffusive mobility. Computational simulation provides further confirmation for the sequential reaction steps and for the details of the associated structural dynamics. The successful quantitative modeling of the low‐temperature decelerated melting of zeolite crystals, reconciling homogeneous with heterogeneous processes, should serve as a platform for understanding the inherent instability of other zeolitic structures, as well as the prolific and more complex nanoporous metal–organic frameworks.
Wafer Scale Transfer of Ultrathin Silicon Chips on Flexible Substrates for High Performance Bendable Systems
Authors: Navaraj William Taube , Gupta Shoubhik , Lorenzelli Leandro , Dahiya Ravinder
Published: March 2018

This paper presents an innovative approach for wafer scale transfer of ultrathin silicon chips on flexible substrates. The methodology is demonstrated with various devices (ultrathin chip resistive samples, metal oxide semiconductor (MOS) capacitors and n‐channel metal oxide semiconductor field effect transistors (MOSFETs)) on wafers up to 4″ diameter. This is supported by extensive electromechanical characterization and theoretical analysis, including finite element simulation, to evaluate the effect of bending and the critical breaking radius of curvature. The ultrathin chips on polyimide did not break until the radius of curvature of 1.437 mm. In the case of MOS capacitors the measured capacitance increases with increase in bending load. The changes in the transfer and output characteristics of ultrathin MOSFETs closely match with the theoretical model utilizing empirically determined parameters. Overall, the work demonstrates the efficacy of the new methodology presented here for wafer scale transfer of ultrathin chips on flexible substrates. The presented research will be useful for obtaining high performance and compact circuits needed in many futuristic flexible electronics applications such as implantable electronics and flexible displays. Further, it will open new avenues for realizing multilayered multimaterial (foil‐to‐foil) integrated bendable electronics.