bluuebunny/crossref_metadata_2025 huggingface dataset:
Soft Magnetic Materials
Authors: Fiorillo Fausto , Bertotti Giorgio , Appino Carlo , Pasquale Massimo
Published: November 2016

This article provides a summary of the basic properties and the essential phenomenology of application‐oriented soft magnetic materials. Starting from an introductory section, where the magnetization process and the involved energetic aspects are highlighted, the physical rationale for the soft magnetic behavior of the materials is discussed, and a comparative illustration of their main physical, mechanical, and magnetic parameters is provided, the materials are classified according to their composition. We start from pure iron, the historical benchmark for any magnetic material, and pass through the selected alloys and compounds displaying the right combination of properties, including abundance of raw elements and costs, making them attractive for applications. We thus illustrate preparation methods, physical and magnetic properties, and applicative attributes of the following materials: (i) pure iron and low‐carbon steels; (ii) nonoriented and grain‐oriented Fe–Si alloys; (iii) High‐Si, Fe–Al, and Fe–Al–Si alloys; (iv) soft magnetic composites; (v) amorphous alloys; (vi) nanocrystalline alloys; (vii) Ni–Fe and Co–Fe alloys; (viii) soft ferrites. For each material, we summarize (i) compositional features and intrinsic physical and magnetic properties; (ii) metallurgical aspects and preparation techniques; (iii) magnetization process and magnetic hysteresis; (iv) energy losses and their dependence on the magnetizing frequency; (v) dependence of the magnetic properties on temperature and stress; (vi) mechanical properties; (vii) applications.
Robotic Assistive Devices for Motor Disability Rehabilitation
Authors: Alamdari Aliakbar , Krovi Venkat
Published: November 2016

Mankind has traditionally developed manipulative and locomotive tools to enhance the ability and performance, increase, strength to and reduce performance variability. In a motor rehabilitation context, such devices enable people with disabilities to perform many activities of daily living, to lead independent lives, and play a more productive role in society.

In this article, we present a review of the technology underlying assistive devices for people with manipulative and locomotive disabilities focusing on prosthetic limbs, robotic arms, exoskeletons, braces, and wheelchairs. We highlight the important role that robotics can play in assistive devices. There is another class of assistive devices, called teletheses, that bear a strong resemblance to the multiple degree‐of‐freedom robot arms and to the body‐powered prosthetic limbs. Finally, we discuss the design and manufacturing issues for such devices. The high degree of customization that is required and the one‐of‐a‐kind flavor of these products suggest that a computer‐integrated, automated approach to design and prototyping is necessary for manufacturing.
All‐Optical Wavelength Conversion
Authors: Lazarou Ioannis , Avramopoulos Hercules
Published: November 2016

This article overviews the fundamental principles and attributes of the major all‐optical signal wavelength conversion (AOWC) methods commonly found in the literature over the last 25 years from the system perspective, which are oriented mainly for telecommunications applications. Two principal AOWC categories are analyzed: first, the optically controlled gates based on semiconductor optical amplifiers (SOAs) or electroabsorption modulators (EAMs) and second, the wave‐mixing AOWC schemes exploitingχ(3)orχ(2)material nonlinearities. In the case of the SOA‐based gates, the effects of cross gain modulation (XGM) and cross phase modulation (XPM) – with or without the employment of the offset filtering technique – are explained and a brief description of the regenerative schemes with SOA‐MZI (Mach‐Zehnder interferometer) switches is attempted. For the case of EAM‐based gates, both XAM and XPM effects are mentioned, utilized for efficient AOWC of intensity‐modulated signals. The wave‐mixing methods, covered in Section 2 of the article, start with the four wave mixing (FWM) effect onχ(3)materials, describing methods to implement polarization insensitive operation. Special attention on the AOWC of advanced modulation formats is attempted by explaining methods on minimizing the phase noise induced on the conversion process. For AOWC onχ(2), materials the fundamental effects of difference frequency generation (DFG), sum frequency generation (SFG), and sum harmonic generation (SHG) are explained. In addition, particular focus is put on the attributes and the wavelength mapping of the cascaded cSFG/DFG and cSHG/DFG processes utilized in most AOWC‐schemes based onχ(2)nonlinearities.
Liquid Antennas
Authors: Zou Meng , Hu Zhenxin , Hua Changzhou , Shen Zhongxiang
Published: November 2016

A brief overview of recent activities in the area of liquid antennas has been provided in this article. This article is organized as follows. Section 2 describes the details of the electrical properties of liquids. In Section 3, liquid antennas based on pure water as a dielectric material are introduced. The development of liquid metal antenna is described in Section 4. Section 5 focuses on the design and characterization of seawater antennas. Section 6 concludes the article by suggesting topics for further studies.
Consensus in Multi‐Agent Systems
Authors: Proskurnikov Anton V. , Cao Ming
Published: November 2016

Many cooperative behaviors of multi‐agent teams emerge fromlocalinteractions among the agents, where an agent interacts with a few “adjacent” teammates, but has no information about the remaining agents. For instance, the self‐organization of many biological populations –including swarms of insects, flocks of birds, and schools of fish –are based on such local interaction rules: the motion and decisions of an individual agent are determined by the behavior of itsnearest neighborsin the population. A special case of multi‐agent coordination isconsensus, that is, the agreement of agents on some quantity of interest or, more generally, the full or partial synchronization of their state trajectories. Establishing consensus is a “benchmark” problem in multi‐agent systems study, which allows to reveal the main principles of multi‐agent coordination and, in particular, the role of the system's interaction graph (or topology). Consensus lies in the heart of many natural phenomena (e.g., synchronous oscillation of neural cells, which maintains a stable heart rhythm) and engineering designs (e.g., attitude synchronization of satellites). In this article, we give a brief review of distributed consensus algorithms, focusing on the basic ideas and relevant mathematical theory, in particular, graph‐theoretic methods.
The Tunnel Field‐Effect Transistor
Authors: Verreck Devin , Groeseneken Guido , Verhulst Anne
Published: November 2016

Scaling of metal‐oxide‐semiconductor field‐effect transistors (MOSFET) is hitting fundamental limits due to power issues. In this article, an alternative transistor concept, the tunnel FET (TFET), is discussed, which employs quantum mechanical band‐to‐band tunneling to reduce power consumption. The main operating principle is explained, followed by a discussion of different modeling approaches. Next, the main performance challenges are presented. Different options to overcome these challenges are discussed. These options include a different material choice and alternative implementations, including dopant pockets, improved gate configurations, and strain. Specific considerations for using TFET in a circuit are highlighted. The article concludes with an overview of experimental realizations.
L‐Probe Patch Antennas on Dielectric Substrate
Authors: Lai Hau Wah , Luk Kwai Man
Published: November 2016

This article introduces the performance of conventional probe‐fed patch antennas with different substrate layers. Then, the geometry of L‐probe fed patch antennas with multiple dielectric layers is discussed. By embedding layers of finite dielectric materials, the L‐probe fed patch antennas achieve wideband performance. The low‐profile characteristic of patch antenna is also retained, and the size of the antenna can be minimized to have a surface area. It is expected that the L‐probe patch antenna design would be attractive in base station antenna design for MIMO (multiple input and multiple output) systems with its characteristics of low profile and compact size.
Photoacoustic Tomography Enhanced by Nanoparticles
Authors: Li Lei , Yao Junjie , Wang Lihong V.
Published: November 2016

Photoacoustic tomography (PAT) is a multicontrast and omniscale imaging modality that can provide anatomical, functional, metabolic, and molecular images of biological tissue ranging from organelles to organs or small‐animal organisms. PAT can provide up to submicrometer spatial resolution at shallow depths and hundreds of micrometer resolution at centimeters depths, employing either endogenous or exogenous contrasts. In particular, nanoparticles, as exogenous contrasts, absorb near‐infrared light much more strongly than endogenous chromophores; thus, they can enhance PAT with significantly improved detection sensitivity, imaging contrasts, and specificity at depths. This article reviews the use of nanoparticles to enhance PAT in various biomedical applications. Taking advantage of nanoparticles engineered with different structures and functions, PAT can target specific molecules or cells. By manipulating nanoparticles with light or ultrasound, enhanced PAT can improve drug delivery efficiency and guide therapy. In summary, nanoparticle‐enhanced PAT shows great potential for high‐sensitivity, high‐specificity deep tissue imaging, especially for cancer diagnosis and therapy, and for treatment monitoring.
Radiation Chemistry of Polymers
Authors: Hill David J. T. , Whittaker Andrew K.
Published: November 2016

Polymeric materials are exposed to high energy radiation either deliberately to alter their properties or inadvertently during their use in high dose environments. As a consequence, an understanding of how radiation modifies polymer structure, and hence properties, is essential for many applications. In addition, the understanding of the degradation of polymers with light or heat can benefit from knowledge of the reaction pathways of radical and charged species formed on irradiation with high energy photons. This article aims to provide a broad overview of the fundamental processes occurring during radiolysis of polymers. This is achieved through a discussion of the interaction of high energy photons with matter, and the subsequent reactions of mainly radical intermediates. Polymers either cross‐link or degrade on exposure to radiation, and the final properties of the polymers depend critically on the balance of these main reaction pathways. Examples are taken from the literature to illustrate how the tendency to undergo cross‐linking or main‐chain scission depends on the polymer structure. The overall yield of reactions can be greatly reduced by the introduction of aromatic groups into the polymer structure. On the other hand, yields can be increased by the inclusion of radiation‐sensitive groups such as sulfones. Similarly, the rates of reactions and the balance between cross‐linking and scission can depend sensitively on the radiolysis temperature. While this review focuses on a discussion of the reactions occurring on radiolysisin vacuo, the effect of the presence of dissolved oxygen on the reaction pathways is also briefly addressed.
Nitroxide‐Mediated Polymerization
Authors: Vivaldo‐Lima Eduardo , Jaramillo‐Soto Gabriel , Penlidis Alexander
Published: November 2016

Nitroxide‐mediated polymerization (NMP) has been studied abundantly in the past three decades. There are several very good and recent reviews on the topic available in the literature. Although in this article we provide an overview on the research efforts focused on the polymer chemistry of NMP, our emphasis is placed on research aspects of NMP from a polymer reaction engineering perspective. Namely, we emphasize the use of engineering tools (such as mathematical modeling) on the design, analysis, and control of NMP processes (process engineering) and the well‐defined microstructures obtained by NMP (product engineering). These aspects are not sufficiently discussed or even included in previous reviews on NMP. Despite of all the intensive research programs carried out in academia and industrial research centers over 30 years, there are still several issues that limit the commercial exploitation of NMP. These issues, which include slow polymerization rates, reduced amount of monomers amenable for polymerization by NMP, low molecular weights, and insufficient commercial availability of NMP controllers, are also discussed.
Heme binding and peroxidase activity of a secreted minicatalase
Authors: Mori Giulia , Doniselli Nicola , Faroldi Federica , Percudani Riccardo
Published: November 2016

Microbial pathogens often require efficient and robust H2O2 scavenger activities to survive in the presence of reactive oxygen species generated by inflammatory responses. In addition to catalases and peroxidases, enzymes known to scavenge H2O2, a novel class of secreted minicatalases is found in diderm bacteria. Here, we characterize the Helicobacter pylori (Hp) minicatalase: a monomeric hemoprotein with catalase core homology. Overexpression of Hp minicatalase rescued a catalase/peroxidase‐deficient Escherichia coli phenotype under aerobic conditions and limited H2O2 stress. The purified enzyme lacks catalase activity, but has strong (kcat > 100 s−1) H2O2‐dependent peroxidase activity toward a variety of organic substrates. Our investigations into heme binding revealed that the heme cofactor is assembled in the periplasm to form the functional holoprotein. Furthermore, we observed the presence of a disulfide bond near the heme cavity of Hp minicatalase, which is conserved in secreted minicatalases and, therefore, may play a role in heme binding.
Both bulk and cancer stem cell subpopulations in triple‐negative breast cancer are susceptible to Wnt, HDAC, and ERα coinhibition
Authors: Sulaiman Andrew , Sulaiman Brandon , Khouri Lara , McGarry Sarah , Nessim Carolyn , Arnaout Angel , Li Xuguang , Addison Christina , Dimitroulakos Jim , Wang Lisheng
Published: November 2016

Development of targeted therapies for triple‐negative breast cancer (TNBC, a more aggressive subtype) is an unmet medical need. We analyzed data from 887 patients with invasive breast cancer and observed that increased Wnt and histone deacetylase (HDAC) activities are associated with estrogen receptor 1 (ESR1) and progesterone receptor (PGR) repression, poor survival, and increased relapse. The inverse correlation between Wnt signaling and repression of ESR1 and PGR expression was found to be magnified in cancer stem cell (CSC) subpopulations in TNBC cell lines. Cosuppression of Wnt, HDAC, and ESR1 using clinically relevant low‐dose inhibitors effectively repressed both bulk and CSC subpopulations and converted CSCs to non‐CSCs in TNBC cells without affecting MCF‐10A mammary epithelial cells.
Strengths and weaknesses of temporal stability analysis for monitoring and estimating grid‐mean soil moisture in a high‐intensity irrigated agricultural landscape
Authors: Ran Youhua , Li Xin , Jin Rui , Kang Jian , Cosh Michael H.
Published: November 2016

Monitoring and estimating grid‐mean soil moisture is very important for assessing many hydrological, biological, and biogeochemical processes and for validating remotely sensed surface soil moisture products. Temporal stability analysis (TSA) is a valuable tool for identifying a small number of representative sampling points to estimate the grid‐mean soil moisture content. This analysis was evaluated and improved using high‐quality surface soil moisture data that were acquired by a wireless sensor network in a high‐intensity irrigated agricultural landscape in an arid region of northwestern China. The performance of the TSA was limited in areas where the representative error was dominated by random events, such as irrigation events. This shortcoming can be effectively mitigated by using a stratified TSA (STSA) method, proposed in this paper. In addition, the following methods were proposed for rapidly and efficiently identifying representative sampling points when using TSA. (1) Instantaneous measurements can be used to identify representative sampling points to some extent; however, the error resulting from this method is significant when validating remotely sensed soil moisture products. Thus, additional representative sampling points should be considered to reduce this error. (2) The calibration period can be determined from the time span of the full range of the grid‐mean soil moisture content during the monitoring period. (3) The representative error is sensitive to the number of calibration sampling points, especially when only a few representative sampling points are used. Multiple sampling points are recommended to reduce data loss and improve the likelihood of representativeness at two scales.
Was breaking the taboo on research on climate engineering via albedo modification a moral hazard, or a moral imperative?
Authors: Lawrence Mark G. , Crutzen Paul J.
Published: November 2016

The topic of increasing the reflectivity of the Earth as a measure to counteract global warming has been the subject of high‐level discussions and preliminary research since several decades, though prior to the early 2000s there was only very limited research on the topic. This changed in the mid‐2000s, particularly following the publication of a special section of Climatic Change with a lead paper by Crutzen [2006], which posited the idea of stratospheric aerosol injections as a possible solution to a policy dilemma. The discussions around the publication of Crutzen [2006] demonstrated how contentious the topic was at that time. The special section of Climatic Change contributed to breaking the “taboo” on albedo modification research that was perceived at that time, and scientific publications on the topic have since proliferated, including the development of several large national and international projects, and the publication of several assessment reports over the last decade. Here we reflect on the background and main conclusions of the publications in 2006, the developments since then, and on some of the main developments over the next decade that we anticipate for research and dialogue in support of decision‐making and policy development processes.
Fire and deforestation dynamics in Amazonia (1973–2014)
Authors: van Marle Margreet J. E. , Field Robert D. , van der Werf Guido R. , Estrada de Wagt Ivan A. , Houghton Richard A. , Rizzo Luciana V. , Artaxo Paulo , Tsigaridis Kostas
Published: November 2016

Consistent long‐term estimates of fire emissions are important to understand the changing role of fire in the global carbon cycle and to assess the relative importance of humans and climate in shaping fire regimes. However, there is limited information on fire emissions from before the satellite era. We show that in the Amazon region, including the Arc of Deforestation and Bolivia, visibility observations derived from weather stations could explain 61% of the variability in satellite‐based estimates of bottom‐up fire emissions since 1997 and 42% of the variability in satellite‐based estimates of total column carbon monoxide concentrations since 2001. This enabled us to reconstruct the fire history of this region since 1973 when visibility information became available. Our estimates indicate that until 1987 relatively few fires occurred in this region and that fire emissions increased rapidly over the 1990s. We found that this pattern agreed reasonably well with forest loss data sets, indicating that although natural fires may occur here, deforestation and degradation were the main cause of fires. Compared to fire emissions estimates based on Food and Agricultural Organization's Global Forest and Resources Assessment data, our estimates were substantially lower up to the 1990s, after which they were more in line. These visibility‐based fire emissions data set can help constrain dynamic global vegetation models and atmospheric models with a better representation of the complex fire regime in this region.
Mapping of hydrocarbons and H3+ emissions at Jupiter's north pole using Galileo/NIMS data
Authors: Altieri F. , Dinelli B. M. , Migliorini A. , Moriconi M. L. , Sindoni G. , Adriani A. , Mura A. , Fabiano F.
Published: November 2016

In this paper we report the mapping of H3+, C2H2, and CH4 as derived by an unexploited Galileo/Near‐Infrared Mapping Spectrometer (NIMS) data set. As previously observed, hydrocarbons emissions appear to be located in the internal part of the auroral main oval, where CH4 3 µm vibrational band intensity ratios suggest that nonthermal excitation mechanisms, such as auroral particle precipitation and/or Joule heating, are responsible for the observed emissions. Temperature estimation are in good agreement for the CH4‐emitting region on the hot spot, while the values obtained for H3+ are lower in comparison with Cassini/visual and infrared mapping spectrometer and ground‐based data. C2H2 emission overlaps the CH4 one only at higher latitudes >75°N, indicating that different energetic particles are at work inside the main oval polar ward. CH4 is also found on the northern section of the main oval (135°< longitude <190°, 60°< latitude <90°N). The present investigation results have implications on the Juno/Jovian InfraRed Auroral Mapper observation planning as well as on the codes that will be used to retrieve temperatures and densities of all the emitting species involved in the Jupiter auroral processes.
Where the continent ends
Authors: Paris Paul J. , Walsh J. P. , Corbett D. Reide
Published: November 2016

The Earth's continents and islands are bordered by shallow ocean plains that are arguably the most environmentally, economically, and politically important parts of the sea. Yet in spite of this, they remain poorly defined and understood. A quantitative approach is employed here to map and analyze these plains, or shelves. The Earth's ocean bathymetry was used to determine the continent‐ocean basin transition at ~1200 m and then parsed with a novel geospatial terrain classification concept/method borrowed from the field of image analysis: the geomorphic phonotype, or geomorphon. The technique is less subjective than visual interpretation and digitization and here illustrates that the ocean coastal plains are deeper, wider, and more steeply sloped than previously recognized. Their variable form is related to tectonics and latitude and ultimately affects function and habitat.
Storm impact on sea surface temperature and chlorophyll a in the Gulf of Mexico and Sargasso Sea based on daily cloud‐free satellite data reconstructions
Authors: Shropshire Taylor , Li Yizhen , He Ruoying
Published: November 2016

Upper ocean responses to tropical storms/hurricanes have been extensively studied using satellite observations. However, resolving concurrent sea surface temperature (SST) and chlorophyll a (chl a) responses along storm tracks remains a major challenge due to extensive cloud coverage in satellite images. Here we produce daily cloud‐free SST and chl a reconstructions based on the Data INterpolating Empirical Orthogonal Function method over a 10 year period (2003–2012) for the Gulf of Mexico and Sargasso Sea regions. Daily reconstructions allow us to characterize and contrast previously obscured subweekly SST and chl a responses to storms in the two main storm‐impacted regions of the Atlantic Ocean. Statistical analyses of daily SST and chl a responses revealed regional differences in the response time as well as the response sensitivity to maximum sustained wind speed and translation speed. This study demonstrates that SST and chl a responses clearly depend on regional ocean conditions and are not as universal as might have been previously suggested.
Lithosphere thinning induced by slab penetration into a hydrous mantle transition zone
Authors: Wang Zhensheng , Kusky Timothy M. , Capitanio Fabio A.
Published: November 2016

Water plays an important role in deformation and partial melting of Earth's mantle. The mantle transition zone (MTZ) is a deep reservoir of bound water from subducting slabs. When this reservoir is perturbed by subducting slabs, water is released, impacting the rheology and dynamics of the mantle. We model the role of released water from the MTZ in lithospheric destruction, deformation and deep‐source magmatism. Comparing the model results from the North China Craton, we infer that the first peak period of magmatism during craton destruction and lithospheric removal (135–115 Ma) resulted from the subducting Izanagi plate perturbing the strongly hydrous MTZ, whereas the second peak period of magmatism (80 Ma‐Cenozoic) is related to extension and asthenospheric partial melting caused by Pacific slab rollback.
High‐accuracy measurements of total column water vapor from the Orbiting Carbon Observatory‐2
Authors: Nelson Robert R. , Crisp David , Ott Lesley E. , O'Dell Christopher W.
Published: November 2016

Accurate knowledge of the distribution of water vapor in Earth's atmosphere is of critical importance to both weather and climate studies. Here we report on measurements of total column water vapor (TCWV) from hyperspectral observations of near‐infrared reflected sunlight over land and ocean surfaces from the Orbiting Carbon Observatory‐2 (OCO‐2). These measurements are an ancillary product of the retrieval algorithm used to measure atmospheric carbon dioxide concentrations, with information coming from three highly resolved spectral bands. Comparisons to high‐accuracy validation data, including ground‐based GPS and microwave radiometer data, demonstrate that OCO‐2 TCWV measurements have maximum root‐mean‐square deviations of 0.9–1.3mm. Our results indicate that OCO‐2 is the first space‐based sensor to accurately and precisely measure the two most important greenhouse gases, water vapor and carbon dioxide, at high spatial resolution (1.3 × 2.3 km2) and that OCO‐2 TCWV measurements may be useful in improving numerical weather predictions and reanalysis products.
On the frequency of the 2015 monsoon season drought in the Indo‐Gangetic Plain
Authors: Mishra Vimal , Aadhar Saran , Asoka Akarsh , Pai Sivananda , Kumar Rohini
Published: November 2016

The 2015 drought in the Indo‐Gangetic Plain posed new challenges related to food and water security and affected the lives of millions. All‐India monsoon rainfall in 2015 was the tenth driest year on record (1906–2015) with a deficit of 14.5%, and the Indo‐Gangetic Plain witnessed a rainfall deficit of 25.8% (third rank event). Drought severity was amplified by deficits from the previous years in the Indo‐Gangetic Plain and other parts of India. The Indo‐Gangetic Plain faced a 2 year cumulative deficit of 51%, and the drought of 2014–2015 was unprecedented with a return period of 542 years. The GRACE data showed the occurrence of consecutive negative terrestrial water storage and groundwater anomalies in 2014 and 2015, mainly centered over the Indo‐Gangetic Plain region. Notwithstanding uncertainty in future projections, the multiyear droughts in the same regions can pose challenges for water resources and agriculture.
Visualizing and verifying probabilistic forecasts of the Madden‐Julian Oscillation
Authors: Marshall Andrew G. , Hendon Harry H. , Hudson Debra
Published: November 2016

We describe a new approach for presenting probabilistic forecasts of the Madden‐Julian Oscillation (MJO) based on the community standard Real‐time Multivariate MJO (RMM) index, using forecasts from version 2 of the Predictive Ocean Atmosphere Model for Australia. This new display overcomes the difficulty of interpreting a dispersive ensemble plume and directly quantifies the probability for the MJO to occur in each of its eight RMM‐defined phases as well as the weak phase. Beyond monitoring and interpreting predictions of the MJO, this new approach also provides a basis for forecast verification using probability‐based skill scores. Here we present a clear and concise quantitative summary of this innovative method for accessing probability of the state of the MJO in an ensemble forecast. This new method compliments the traditional MJO ensemble forecast display and verification and will benefit global forecasting centers, international MJO working groups, and the World Meteorological Organization Subseasonal to Seasonal Project.
Surface elevation change and mass balance of Icelandic ice caps derived from swath mode CryoSat‐2 altimetry
Authors: Foresta L. , Gourmelen N. , Pálsson F. , Nienow P. , Björnsson H. , Shepherd A.
Published: November 2016

We apply swath processing to CryoSat‐2 interferometric mode data acquired over the Icelandic ice caps to generate maps of rates of surface elevation change at 0.5 km postings. This high‐resolution mapping reveals complex surface elevation changes in the region, related to climate, ice dynamics, and subglacial geothermal and magmatic processes. We estimate rates of volume and mass change independently for the six major Icelandic ice caps, 90% of Iceland's permanent ice cover, for five glaciological years between October 2010 and September 2015. Annual mass balance is highly variable; during the 2014/2015 glaciological year, the Vatnajökull ice cap (~70% of the glaciated area) experienced positive mass balance for the first time since 1992/1993. Our results indicate that between glaciological years 2010/2011and 2014/2015 Icelandic ice caps have lost 5.8 ± 0.7 Gt a−1 on average, ~40% less than the preceding 15 years, contributing 0.016 ± 0.002 mm a−1 to sea level rise.
Response of Jupiter's inner magnetosphere to the solar wind derived from extreme ultraviolet monitoring of the Io plasma torus
Authors: Murakami Go , Yoshioka Kazuo , Yamazaki Atsushi , Tsuchiya Fuminori , Kimura Tomoki , Tao Chihiro , Kita Hajime , Kagitani Masato , Sakanoi Takeshi , Uemizu Kazunori , Kasaba Yasumasa , Yoshikawa Ichiro , Fujimoto Masaki
Published: November 2016

Because Jupiter's magnetosphere is huge and is rotationally dominated, solar wind influence on its inner part has been thought to be negligible. Meanwhile, dawn‐dusk asymmetric features of this region have been reported. Presence of dawn‐to‐dusk electric field is one of the leading explanations of the asymmetry; however, the physical process of generating such an intense electric field still remains unclear. Here we present long and continuous monitoring of the extreme ultraviolet emissions from the Io plasma torus in Jupiter's inner magnetosphere made by the Hisaki satellite between December 2013 and March 2014. We found five occasions where the dusk/dawn brightness ratio was enhanced above 2.5 in response to rapid increase of the solar wind dynamic pressure. The enhancement is achieved as the dusk region brightens and the dawn region dims. The observation indicates that dawn‐to‐dusk electric field in the inner magnetosphere is enhanced under compressed conditions.
Transmitted, reflected, quasi‐reflected, and multiply reflected ions in low‐Mach number shocks
Authors: Gedalin M.
Published: November 2016

The dependence of ion dynamics on the cross‐shock potential and upstream βi in low‐Mach number marginally critical shocks is studied using advanced test particle analysis,. The directly transmitted ions provide the main contribution to the downstream ion pressure. The fraction of reflected ions increases with the increase of the cross‐shock potential and βi. This fraction is small and their contribution to the downstream ion pressure is negligible in marginally critical shocks. A population of quasi‐reflected ions is identified. These ions make a loop inside the ramp and do not appear upstream. They acquire energies comparable to the energies of the true reflected ions, are observed as a halo in the downstream ion distribution, and contribute significantly to the downstream pressure. Thus, the transmitted and quasi‐reflected ions shape the downstream magnetic profile. At higher cross‐shock potentials and βi the reflected ions cause formation of a magnetic dip just ahead of the ramp. A small fraction of ions are multiply reflected at the shock front. All these ions escape into the upstream region and all escaping ions are mutliply reflected.
Geomagnetically induced currents in the Irish power network during geomagnetic storms
Authors: Blake Seán P. , Gallagher Peter T. , McCauley Joe , Jones Alan G. , Hogg Colin , Campanyà Joan , Beggan Ciarán D. , Thomson Alan W. P. , Kelly Gemma S. , Bell David
Published: November 2016

Geomagnetically induced currents (GICs) are a well‐known terrestrial space weather hazard. They occur in power transmission networks and are known to have adverse effects in both high‐latitude and midlatitude countries. Here we study GICs in the Irish power transmission network (geomagnetic latitude 54.7–58.5°N) during five geomagnetic storms (6–7 March 2016, 20–21 December 2015, 17–18 March 2015, 29–31 October 2003, and 13–14 March 1989). We simulate electric fields using a plane wave method together with two ground resistivity models, one of which is derived from magnetotelluric measurements (magnetotelluric (MT) model). We then calculate GICs in the 220, 275, and 400 kV transmission network. During the largest of the storm periods studied, the peak electric field was calculated to be as large as 3.8 V km−1, with associated GICs of up to 23 A using our MT model. Using our homogenous resistivity model, those peak values were 1.46 V km−1 and 25.8 A. We find that three 400 and 275 kV substations are the most likely locations for the Irish transformers to experience large GICs.
Demasking the integrated information of discharge: Advancing sensitivity analysis to consider different hydrological components and their rates of change
Authors: Guse Björn , Pfannerstill Matthias , Gafurov Abror , Fohrer Nicola , Gupta Hoshin
Published: November 2016

Discharge as an integrated representation of all hydrological processes is the most common response variable used in sensitivity analyses. However, due to overlaying effects of all hydrological processes, the sensitivity signal of certain parameters to discharge can be masked. A more informative form of sensitivity analysis can be achieved by investigating how parameter sensitivities are related to individual modeled hydrological components. In our study, the TEDPAS (TEmporal Dynamics of PArameter Sensitivity) methodology is used to calculate daily sensitivities to modeled hydrological components and to detect temporal variations in dominant parameters. As a further enhancement to consider both magnitude and dynamics, temporal variations in parameter dominance are analyzed, both for magnitudes and rates of change of hydrological components. For this purpose, regime curves for parameter sensitivities are constructed. The results demonstrate that sensitivities of parameters increase when using the corresponding hydrological component instead of discharge as response variable. For each hydrological component, seasonal patterns of parameter dominance are detected using both magnitude and rate of change as response variable. Major differences are detected for certain capacity parameters, which are less pronounced using rates of change. Overall, we show that disentangling the diagnostic information hidden in the integrated signal of discharge can lead to a more informative signal regarding the sensitivity of hydrological components. Such advancements in sensitivity analysis can lead to a better understanding of how model parameters control the individual hydrological components in time.
Chromosome Mechanics
Authors: LeClair Renée J , Best Robert G
Published: November 2016

Chromosome mechanics describes the processes of chromosome replication and interactions during somatic cell division and gametogenesis. Mitosis can be divided into two phases consisting of nuclear and cytoplasmic division ultimately producing identical diploid somatic cells. Segregation during mitosis is largely dependent on chromosomal attachment to the mitotic spindle with a fully developed kinetochore structure. This is in contrast to meiosis where cells undergo two rounds of nuclear division to produce haploid germ cells. During this process, homologous chromosomes pair at the cellular midline allowing for exchange of deoxyribonucleic acid (DNA) between parental alleles and stabilisation of the chromosome structures during separation. Aberrations occurring in either mitosis or meiosis can result in numerical abnormalities (from nondisjunction events) which often result in nonviable offspring. However, there are some aneuploidies that are viable with trisomy 21 being the most common example of this. Similarly, unrepaired DNA damage resulting in chromosomal breakage and structural rearrangements. These large‐scale genetic changes reduce the genetic efficacy of a cell ultimately leading to cancer or cell death. In summary, mitosis and meiosis are integral parts of the cellular life cycle and both processes are essential at maintaining genomic stability within an organism.

Key Concepts

The cell cycle comprises two main phases: mitosis, where cell division occurs, and interphase, which includes DNA replication and the expression of many essential proteins. Interphase can be further divided into G1, S and G2.

Cyclin‐dependent kinases regulate progression through the cell cycle at three major checkpoints: G1, G2 and a spindle checkpoint during mitosis.

Mitosis is the process of cell division resulting in two identical diploid cells and can be divided into prophase, metaphase, anaphase and telophase.

Meiosis is the process of cell division that results in germline cells where following one round to DNA replication, the cell undergoes two cell divisions.

Meiosis in males results in four identical haploid cells, while meiosis in females produces a single mature ovum and three polar bodies.

Aberrations in either mitosis or meiosis can result in nondisjunction resulting in aneuploidy.

Defects in DNA repair mechanisms can also result in chromosome damage or breaking which will negatively impact the process of cell division.
Sequencing the Human Genome: Novel Insights into Its Structure and Function
Authors: Kehrer‐Sawatzki Hildegard , Cooper David N
Published: November 2016

The availability of the human genome sequence has had an enormous impact on biomedical research. New discoveries emanating directly from the elucidation of the human genome sequence have included the unexpectedly low total number of genes, the existence of numerous transcribed but noncoding sequences and the multiplicity of low‐copy repeats and segmental duplications. The Human Genome Project has also spawned new research projects such as Encyclopedia of DNA Elements (ENCODE), Haplotype Map (HapMap) 1000 Genomes Project and the Human Variome Project which together are helping to reveal the remarkable complexity and diversity of the human genome. Finally, comparison of the human reference genome sequence with the genomes of other human species such as the Neanderthal and Denisovan or with other vertebrates has opened up numerous research avenues in evolutionary biology.

Key Concepts

The Human Genome Project has yielded a high‐quality sequence of the human genome which has been available to researchers for more than 10 years.

The 3 billion nucleotide reference assembly has been a prerequisite for the annotation of >22 800 different protein‐coding genes as well as thousands of RNA genes and transcripts of unknown function.

Some 16 000 pseudogenes have also been identified, some of which could encode novel proteins or regulatory RNAs.

Tens of millions of single‐nucleotide polymorphisms have been described as well as tens of thousands of structural variants.

The genome has been found to contain a multitude of structural features such as segmental duplications, transposon‐derived repeats, processed pseudogenes, simple sequence repeats and the blocks of tandemly repeated sequences at the centromeres and telomeres.

Now that the basic structure of the human genome has been elucidated, the focus has switched to trying to understand the function of its components.

The human genome contains noncoding ultraconserved elements which may represent long‐range enhancers of gene expression. The recognition of such elements is serving to change our conception of the nature of the gene.
Pathological Variations in 3′‐Untranslated Regions of Human Genes
Authors: Pal Jayanta K , Chatterjee Sangeeta , Rao Shilpa J
Published: November 2016

The 3′‐untranslated regions (UTRs) of messenger ribonucleic acids (mRNAs) play a critical role in the stabilisation, localisation and translation of mRNAs. Mutations that disrupt functional elements of the 3′‐UTR of mRNAs such as polyadenylation signal, microribonucleic acid (miRNA) target sites and AU‐rich elements lead to production of nonfunctional proteins or reduced amounts of functional proteins. Genetic variations in the 3′‐UTR are associated with disease risk or diseases such as spinocerebellar ataxia 8, Parkinson disease, breast cancer, atopic dermatitis, papillary thyroid carcinoma and many others. With the advent of genetic counselling and promise of personalised medicine, genetic variation in this region of mRNAs is the focus of intense research. Current research shows that this region is of immense significance in the context of translational research.

Key Concepts

3′‐Untranslated regions (UTRs) are noncoding regions of mRNAs.

The 3′‐UTR is delimited by stop codon (UAA or UAG or UGA) at the 5′‐end and poly (A) tail at the 3′‐end.

Motifs such as AU‐rich elements, polyadenylation signal, iron responsive elements and others are involved in mRNA stability, localisation and translation.

Mutations are changes in the DNA/gene of an organism which are heritable.

Mutations in the AU‐rich elements lead to atypical stabilisation of mRNA and associated diseases.

Mutations that lead to abolition of canonical polyadenylation signal interfere with efficient transcription termination and polyadenylation of mRNA.

Mutations in the 3′‐UTR may alter the binding sites of interacting miRNAs or proteins resulting in deregulation of mRNA translation.

Single‐nucleotide polymorphisms (SNPs) in the 3′‐UTR are associated with individual's drug response and disease risk.
TLymphocytes: Plasticity of Subsets
Authors: Mosmann Tim R , Rebhahn Jonathan A
Published: November 2016

The initial characterisation of both mouse and human T cells described distinct and sharply defined cytokine patterns that were relatively stable and were functionally specialised for successfully attacking different pathogens. Additional phenotypes were then described, extending the range of functional types. However, more recently there have been many reports of further changes in cytokine patterns, and it is clear that all the recognised phenotypes were more plastic than originally thought. In particular, many intermediates between established subsets have been reported, for example Th1/Th17 cells expressing both IFNγ (interferon‐gamma) and IL (interleukin)‐17. This plasticity provides extra versatility for the immune system to adapt to changing infections and to altered requirements in different locations. A model of stochastic differentiation is presented, to visualise potential differentiation modes in the framework of a landscape model and to try to encourage discussion and experimentation regarding different mechanisms for plasticity.

Key Concepts

Initial models of highly stable T‐cell subsets were useful but underestimated diversity.

Flexibility is overlaid on partial stability.

Many intermediate phenotypes can be induced.

Several questions remain regarding temporary versus long‐term plasticity alterations.

Models for visualising differentiation need to be modified to include flexibility around a theme.

Incorporation of stochastic trends may give a more useful representation of differentiation.
Molecular Genetics of
DNA
Polymerase Gamma‐associated Neurodegeneration
Authors: Tzoulis Charalampos , Bindoff Laurence A
Published: November 2016

Polymerase gamma (POLG) mutations are a common cause of mitochondrial disease and have also been linked to neurodegeneration and ageing. POLG mutations impair the maintenance of mitochondrial deoxyribonucleic acid (mtDNA) in cells causing a combination of quantitative mtDNA depletion, which can present in infancy, and the accumulation of deletions and point mutations, which gradually build up over time. In neurones, this increased somatic mtDNA mutagenesis compromises neuronal respiration, primarily in the form of complex I deficiency, which in turn primes neurones for injury. These two distinct but overlapping biological processes are best described as acute on chronic neurodegeneration. The chronic process affects the cerebellum, deep nuclei such as the dopaminergic cells of the substantia nigra and spinal cord and is reflected clinically by progressive spinocerebellar ataxia. In contract, the acute cortical lesions associated with focal neuronal necrosis occur widely and appear to be triggered and or worsened by epileptic seizures.

Key Concepts

Polymerase gamma is the only enzyme that replicates and repairs mitochondrial DNA and comprises one catalytic subunit (pol γ A) encoded by the POLG gene and two accessory subunits (pol γ B) encoded by the POLG1 gene.

POLG dysfunction is a common cause of mitochondrial disease and has been associated with ageing and neurodegeneration.

POLG mutations impair mtDNA homeostasis.

MtDNA loss, depletion, is an early event often present from infancy, whereas deletions and point mutations accumulate gradually during the course of the disease.

Accumulating mtDNA damage leads to respiratory dysfunction and in particular complex I deficiency, compromising ATP production in neurones.

Neuronal populations that are most vulnerable to ATP deficiency, including those in the cerebellum, thalamus and substantia nigra, exhibit a chronic progressive neurodegeneration and a progressive spinocerebellar ataxia.

In spite of severe substantia nigra degeneration and nigrostriatal depletion, patients do not develop clinical parkinsonism, suggesting this is compensated by dysfunction elsewhere in the brain.

Acute cortical lesions appear to be triggered by epileptic seizures and underlie episodes with severe, rapidly progressive encephalopathy, focal neurological dysfunction and high morbidity and mortality.

The most important predictors of prognosis are the presence of a compound heterozygous genotype, an age of onset before 2 years and the presence of epilepsy; these are associated with severe disease, rapid progression and highest mortality rate.

No disease modulating therapy exists for POLG encephalopathy. Efficient control of the epilepsy is the cornerstone of treatment.