bluuebunny/crossref_metadata_2025_split huggingface dataset:
Receiving Antennas
Authors: Nakano Hisamatsu 
Published: May 2016

Abstract
Antennas are used for transmitting and receiving electromagnetic waves. This chapter focuses on receiving antennas and discusses the following topics: vector effective height, open‐circuit voltage, equivalent circuit, and cross section and aperture efficiency of a receiving antenna. The vector effective height is used for calculating the open‐circuit voltage and cross section of a receiving antenna. The equivalent circuit of the receiving antenna is created using two antennas: an open‐circuit receiving antenna and a transmitting antenna. For better understanding, mathematical expressions for these topics are presented, together with examples. Finally, an exercise regarding the receiving antenna characteristics of a novel rectangular loop is presented. The phase constant of the current on this loop is negative across a specific frequency region, which is not found in conventional loop antennas. The exercise is devoted to the analysis of the receiving antenna characteristics when the loop is illuminated by a circularly polarized plane wave.
Optoelectronic Oscillators
Authors: Chi Yu‐Chieh , Lin Gong‐Ru 
Published: May 2016

Abstract

Without the need of any clock source, an optoelectronic oscillator (OEO) enables to simultaneously generate a high‐repetition‐rate optical clock/pulse train with low jitter and a microwave clock with high spectral purity, and it can be employed to further perform signal processing including data generation, pulse shaping, and clock recovery. Therefore, it becomes the center of attention in the microwave photonic technical area. Numerous techniques have been proposed to reduce the single‐sideband (SSB) phase noise and to improve the frequency stability of the OEO. In this article, a historical review of OEOs including different constructing methods and functionalities is introduced. Subsequently, a Mach–Zehnder modulator (MZM)‐based OEO at 40 GHz is focused to implement a synthesizer‐free 40 Gbit/s return‐to‐zero binary phase‐shifted‐keying (RZ‐BPSK) data generator. As a result, the 40 GHz microwave clock with a
Q
‐factor of up to 2 × 10
8
is observed, and its SSB phase noise can be suppressed to −120 dBc/Hz at 100 kHz frequency offset. Moreover, its spectral quality is almost independent of the intraloop fiber‐induced radio‐frequency (RF) power fading. In addition, the delivered optical RZ carrier with a pulse on/off extinction ratio (ER) of 7.7 dB, a pulse width of 10.5 ps, and a timing jitter of 150 fs is particularly suitable for 40 Gbit/s RZ‐BPSK data transmission. At a requested bit error rate (BER) of 10
−9
, a back‐to‐back receiving power sensitivity of −16.3 dBm is observed, which indicates a power penalty of 4 dB after 25 km single‐mode‐fiber (SMF) transmission.
Investigation of H2AX methylation by the SUV39H2 protein lysine methyltransferase
Authors: Schuhmacher Maren Kirstin , Kudithipudi Srikanth , Jeltsch Albert 
Published: May 2016

The H3K9 protein lysine methyltransferase SUV39H2 was reported to methylate K134 of H2AX and stimulate H2AX phosphorylation during DNA damage response [Sone K et al. (2014) Nat Commun 5, 5691]. However, the sequence context of H2AX‐K134 differs from the specificity of SUV39H2. We performed in vitro methylation reactions with SUV39H2 (and its homolog SUV39H1) using H2AX protein and peptides, but no methylation at K134 or any other lysine in H2AX was detected. Positive controls demonstrated the functionality of the assays. While our data cannot finally exclude H2AX methylation of SUV39H2 in cells, additional experimental evidence is required to validate this claim.
Substructures within a dipolarization front revealed by high‐temporal resolution Cluster observations
Authors: Yao Zhonghua , Fazakerley A. N. , Varsani A. , Rae I. J. , Owen C. J. , Pokhotelov D. , Forsyth C. , Guo R. L. , Bai S. C. , Yao S. T. , Doss N. 
Published: May 2016

AbstractThe dipolarization front (DF), usually observed near the leading edge of a bursty bulk flow (BBF), is thought to carry an intense current sufficient to modify the large‐scale near‐Earth magnetotail current system. However, the physical mechanism of the current generation associated with DFs is poorly understood. This is primarily due to the limitations of conventional plasma instruments which are unable to provide a sufficient number of unaliased 3‐D distribution functions on the timescale of the DF, which usually travels past a spacecraft in only a few seconds. It is thus almost impossible to unambiguously determine the detailed plasma structure of the DF at the usual temporal resolution of such instruments. Here we present detailed plasma measurements using the Cluster Plasma Electron and Current Experiment and Cluster Ion Spectrometry‐Composition and Distribution Function ion data for an event during which it was possible to observe the full pitch angle distribution at a cadence of 1/4 s. The observations clearly show details of plasma substructure within the DF, including the presence of field‐aligned electron beams. In this event, the current density carried by the electron beam is much larger than the current obtained from the curlometer method. We also suggest that the field‐aligned current around the DF obtained from the curlometer method may have been misinterpreted in previous studies. Our results imply that the nature of the DF current system needs to be revisited using high‐resolution particle measurements, such as those observations shortly to be available from the Magnetospheric Multiscale mission.
Insights into complex layered ejecta emplacement and subsurface stratigraphy in Chryse Planitia, Mars, through an analysis of THEMIS brightness temperature data
Authors: Jones Eriita , Caprarelli Graziella , Osinski Gordon R. 
Published: May 2016

AbstractLayered ejecta craters on Mars have been interpreted to indicate the presence of volatiles in the substrate, making them important targets for the investigation of sites of astrobiological significance. If the ejecta are associated with the presence of water in the substratum, specific surface grain size trends are expected. In this study we explore the distribution of grain sizes in the layered ejecta of impact craters located in Chryse Planitia, using Thermal Emission Imaging System (THEMIS) thermal infrared data. Ejecta grain size trends, in conjunction with ejecta mobility and lobateness values, are applied to assess the degree of surface flow of the ejecta, and in turn to constrain the plausible volatile abundance, cohesion, and fine particle content of the target materials. Craters with a larger fraction of small grain sizes in their ejecta showed greater ejecta mobility and lobateness, consistent with a water‐rich and/or a low‐cohesion target. Craters displaying decreasing grain size with increasing radius had smaller diameters and lower ejecta mobility and lobateness, indicating only a minimal component of surface ejecta flow. Ejecta grain size trends varied with crater diameter, from which the presence of vertical compositional stratigraphy in Chryse Planitia is inferred and interpreted. Our observations are synthesized into a number of plausible geologic scenarios for Chryse Planitia.
Influences of riverine and upwelling waters on the coastal carbonate system off Central Chile and their ocean acidification implications
Authors: Vargas Cristian A. , Contreras Paulina Y. , Pérez Claudia A. , Sobarzo Marcus , Saldías Gonzalo S. , Salisbury Joe 
Published: May 2016

AbstractA combined data set, combining data from field campaigns and oceanographic cruises, was used to ascertain the influence of both river discharges and upwelling processes, covering spatial and temporal variation in dissolved inorganic carbon (DIC) and aragonite saturation state. This work was conducted in one of the most productive river‐influenced upwelling areas in the South Pacific coasts (36°S). Additionally, further work was also conducted to ascertain the contribution of different DIC sources, influencing the dynamics of DIC along the land‐ocean range. Six sampling campaigns were conducted across seven stations at the Biobío River basin, covering approximately 200 km. Three research cruises were undertaken simultaneously, covering the adjacent continental shelf, including 12 sampling stations for hydrographic measurements. Additionally, six stations were also sampled for chemical analyses, covering summer, winter, and spring conditions over 2010 and 2011. Our results evidenced that seaward extent of the river plume was more evident during the winter field campaign, when highest riverine DIC fluxes were observed. The carbonate system along the river‐ocean continuum was very heterogeneous varying over spatial and temporal scales. High DIC and pCO2 were observed in river areas with larger anthropogenic effects. CO2 supersaturation at the river plume was observed during all campaigns due to the influence of low pH river waters in winter/spring and high‐pCO2 upwelling waters in summer. δ13CDIC evidenced that main DIC sources along the river and river plume corresponded to the respiration of terrestrial organic matter. We have linked this natural process to the carbonate saturation on the adjacent river‐influenced coastal area, suggesting that Ωaragonite undersaturation in surface/subsurface waters is largely modulated by the influence of both river discharge and coastal upwelling events in this productive coastal area. Conditions of low Ωaragonite might impact negatively physiological traits for marine organisms, such as bivalves, gastropods, and crustaceans. Therefore, local populations from river‐influenced sites could be inherently more tolerant to ocean acidification than organisms living in regions with lower Ωaragonite variability.
Cutin and Suberin Polyesters
Authors: Li‐Beisson Yonghua , Verdier Gaëtan , Xu Lin , Beisson Fred 
Published: May 2016

Abstract

Cutin and suberin are cell wall‐associated glycerolipid polymers that are specific to plants. Cutin forms the framework of the cuticle sealing the aerial epidermis, while suberin is present in the periderm of barks and underground organs. Suberised walls are also found in the root endodermis. Barriers based on cutin and suberin restrict the transport of water and solutes across cell walls and limit pathogen invasions. Chemical analysis shows that both polymers are polyesters composed mostly of fatty hydroxyacids, diacids and epoxyacids esterified to each other and to glycerol. Suberin, whose best‐known form is cork, usually differs from cutin (which has C16 and C18 fatty acids) by a higher content of C20–C24 aliphatics and aromatics. In the last 10 years, the identification of mutants of Arabidopsis or other model plants affected in cutin and/or suberin content has allowed the construction of a more complete picture of the polyester biosynthesis pathways, which currently include acyltransferases with unique specificities, fatty acid hydroxylases, acyl‐CoA synthetases, fatty acid elongases, fatty acyl‐CoA reductases, feruloyl transferases, ABC transporters and extracellular transacylases.

Key Concepts

The epidermal cells of plant aerial organs and periderm/endoderm cells synthesise the protective cell wall lipid polymers cutin and suberin respectively.

Cutin and suberin are both polyesters containing glycerol and oxygenated fatty acids.

Cutin structure is not completely understood and suberin structure remains controversial.

Oxygenated fatty acid monomers are produced by fatty acid oxidases of the cytochrome P450 superfamily.

Acylation of oxygenated fatty acids to glycerol is catalysed by special glycerol‐3‐phosphate acyltransferases.

Cutin acylglycerol building blocks are exported to the cell wall and polymerised by extracellular transacylases.

How suberin precursors are assembled is still unknown.
Digital Image Analysis
Authors: Burri Olivier , Guiet Romain , Seitz Arne 
Published: May 2016

Abstract

Light microscopy offers life sciences the possibility to study a variety of organisms on widely differing spatial and temporal scales. Recent years have seen the appearance of a multitude of important light microscopy techniques. To characterise and describe biological processes, however, sheer visualisation of images is inadequate. The assembly of image‐processing algorithms, so‐called workflows, is needed to extract meaningful quantitative data. These workflows are as important as image acquisition and, therefore, are critical components for data acquisition and sample preparation. Here, we describe a variety of image‐processing workflows covering a large part of the biological landscape pointing out common themes and outlining a generic template for workflow assembly.

Key Concepts

Digital image analysis is an important tool to extract meaningful data out of an image.

Digital image analysis is the last component of a workflow comprising sample preparation and image acquisition.

Segmentation allows to identify objects in an image.

Filtering is needed to reduce noise in images from biological samples.

Digital image analysis is the key for reproducible workflows in life sciences.
Gene Therapy for Haemoglobinopathies
Authors: Goodman Michael A , Malik Punam 
Published: May 2016

Abstract

Haemoglobinopathies, including thalassaemia and sickle cell anaemia, are common genetic diseases with significant associated morbidity and mortality. The potentially curative modality, haematopoietic stem cell (HSC) transplant, is restricted to a minority with matched donors, and has potential immunological adverse sequelae. Autologous HSC‐based therapies, using a patient's own genetically modified HSCs as donor cells, eliminates the need for an allogeneic matched donor and the immunological adverse effects of allogeneic HSC transplants. Gene therapy for haemoglobinopathies can be categorised as: (1) gene addition, (2) gene disruption, (3) gene correction, or (4) gene modification resulting in pharmacological upregulation of foetal haemoglobin. Currently, additive gene therapies are in clinical trials, while promising therapies based on gene disruption, editing and modulation of gene regulation are currently under development. Many of these therapies use the latest innovations in gene editing, the designer nucleases, including zinc‐fingers, transcription activator‐like effector nucleases, and clustered regularly interspaced short palindromic repeats/Cas technologies.

Key Concepts

Haemoglobin exists as a heterotetramer of two α‐globin subfamily peptides and two β‐globin subfamily peptides; adult haemoglobin primarily composed of α
2
β
2.

Haemoglobinopathies are genetic diseases that affect either the function or level of globin peptides.

Haemoglobinopathies are the most prevalent genetic diseases with significant morbidity and mortality.

Of these, β‐globinopathies (sickle cell anaemia and β‐thalassaemia) are the most common monogenic diseases worldwide and manifest within 6–12 months of birth.

Severity of haemoglobinopathies can be ameliorated through the expression of the missing haemoglobin subunit beta (HBB), additional β‐like globins, or genes that upregulate alternative globins.

Additive gene therapy using lentivirus vectors has proven to be successful for both β‐thalassaemia and sickle cell anaemia clinically.

Gene editing strategies, using ZFNs, TALENs or CRISPR/Cas, can be used as a ‘fix and run’ approach and have the advantage over additive gene therapies by avoiding insertional genotoxicity and restoring innate regulatory mechanisms.

Erythroid‐specific modulation of
BCL11A
has been shown to increase expression of haemoglobin subunits gamma 1 (HBG1) and gamma 2 (HBG2), and may be a viable alternative treatment modality.
Nonparametric Estimation and Comparison of Species Richness
Authors: Chao Anne , Chiu Chun‐Huo 
Published: May 2016

Abstract

Species richness (the number of species) in an assemblage is a key metric in many research fields of ecology. Simple counts of species in samples typically underestimate the true species richness and strongly depend on sampling effort and sample completeness. Based on possibly unequal‐sampling effort and incomplete samples that miss many species, there are two approaches to infer species richness and make fair comparisons among multiple assemblages,: (1) An asymptotic approach via species richness estimation. This approach aims to compare species richness estimates across assemblages. We focus on the nonparametric estimators that are universally valid for all species abundance distributions. (2) A non‐asymptotic approach via the sample‐size‐ and coverage‐based rarefaction and extrapolation on the basis of standardised sample size or sample completeness (as measured by sample coverage). This approach aims to compare species richness estimates for equally large or equally complete samples. Two R packages (SpadeR and iNEXT) are applied to beetle data for illustration.

Key Concepts

Due to sampling limitation, there are undetected species in almost every biodiversity survey.

Empirical species counts underestimate species richness and highly depend on sampling efforts and sample completeness.

Based on incomplete samples, species richness (observed plus undetected) is statistically difficult to estimate accurately especially for highly diverse assemblages with many rare species.

Abundant species (which are certain to be detected in samples) contain almost no information about the undetected species richness.

Rare species (which are likely to be either undetected or infrequently detected) contain nearly all the information about the undetected species richness.

Most nonparametric estimators of the number of undetected species are based on the frequency counts of the detected rare species, e.g. singletons and doubletons for abundance data.

Nonparametric estimators of species richness are universally valid for all species abundance distributions and thus are more robust than parametric estimators that are based on specified parametric abundance models.

Rarefaction and extrapolation methods allow for fair and meaningful comparison of species richness estimates for standardised samples on the basis of sample size or sample completeness.

Sample‐size‐based rarefaction and extrapolation methods aim to compare species richness estimates for equally large samples determined by samplers.

Coverage‐based rarefaction and extrapolation methods aim to compare species richness estimates for equally complete samples or equal fractions of population individuals reliably estimated from data.
Towards local governance of marine resources and ecosystems on Easter Island
Authors: Aburto Jaime A. , Gaymer Carlos F. , Cundill Georgina 
Published: May 2016

Abstract

Social‐ecological system sustainability depends in part upon the fit between ecosystems and institutions.
In 2014, the local community on Easter Island started a bottom‐up process to improve marine resources conservation and management.
Local stakeholders formed a working group that has regular meetings and goals, such as creating a sea council and some basic action plans, thus initiating a local governance transformation process.
A participatory process was conducted together with a local organization that led the marine conservation issues on the island to define the factors that could favour and/or undermine the formation of the sea council. Also, the stakeholders that must be present in such a sea council were identified.
Twelve factors that could facilitate or hinder the implementation of a sea council were identified. The lack of representativeness of public institutions is a major challenge.
Public institutions are designed to ensure compliance with central government strategies, but the decisions do not represent the worldview of islanders.
The results showed the potential value of conducting a participatory process to identify the key issues that could hinder or favour a desired governance transformation process. The participatory process also highlighted governance mismatches that are important to consider in attempts to pursue more effective fishery governance on Easter Island, and other Island communities.
Centralized governance systems do not respond rapidly to locally observed social and ecological dynamics. By contrast, a local decision‐making system based on traditional laws and local governance can more rapidly respond to observed changes.
The participatory process presented here holds the potential to support local people in their planning and coordination for marine conservation and management in order to optimize bottom‐up change processes involving multiple stakeholders with different interests, values and levels of power.
Copyright © 2016 John Wiley & Sons, Ltd.
Development of the Heart Endocardium at an Early Stage of Chick Embryos Evaluated at Light‐ and Electron‐Microscopic Levels
Authors: Hara Yaiko , Wake Kenjiro , Inoue Kouji , Kuroda Noriyuki , Sato Akie , Inamatsu Mutsumi , Tateno Chise , Sato Tetsuji 
Published: May 2016

ABSTRACTDevelopment of the endocardium in the heart of 4 to 4·1/2‐day‐incubated chick embryos was observed light and electron microscopically, and these results were evaluated by immunohistochemistry for desmin, FLK1 (VEGFR‐2) or CD31, and by in situ hybridization assays for flk1‐mRNA expression. At this developmental stage, the atrium and the ventricle were already discriminated by formation of the atrio‐ventricular junction. The cardiac wall consisted of three layers; the inner endocardium, the middle myocardium, and the outer epicardium. The developing endocardium was seen as a chain of single‐layered endocardial cells. Along its inner surface, numerous clusters of blood corpuscles were distributed, which seemed to contain some undifferentiated endocardial cells estimated from their characteristic ultrastructure and histological topography. Several blood corpuscles were in directly contact with the myocardium at the missing portions of the developing endocardial cell‐chains. Differentiating endocardial cells individually showed roundish, small and large crescent, or flat in shapes. Such a prominent change of cell shapes appeared to be in parallel with their secretory activity during the transformation from the undifferentiated cells to the endocardial cells. Furthermore, immunohistochemistry for FLK1 or CD31, and in situ hybridization assays for flk1‐mRNA labeled the cells composing developing endocardial cell‐chains. Though these expressional analyses could not document clearly the transition of precursor cells into endocardial cells, the present study provided for the first time some important information regarding the morphological transition process toward endocardial cells at ultrastructural levels. Anat Rec, 299:1080–1089, 2016. © 2016 Wiley Periodicals, Inc.
Efficient recombinant expression of SFTI‐1 in bacterial cells using intein‐mediated protein trans‐splicing
Authors: Li Yilong , Aboye Teshome , Breindel Leonard , Shekhtman Alexander , Camarero Julio A. 
Published: May 2016

AbstractWe report for the first time the recombinant expression of bioactive wild‐type sunflower trypsin inhibitor 1 (SFTI‐1) inside E. coli cells by making use of intracellular protein trans‐splicing in combination with a high efficient split‐intein. SFTI‐1 is a small backbone‐cyclized polypeptide with a single disulfide bridge and potent trypsin inhibitory activity. Recombinantly produced SFTI‐1 was fully characterized by NMR and was observed to actively inhibit trypsin. The in‐cell expression of SFTI‐1 was very efficient reaching intracellular concentration ≈ 40 µM. This study clearly demonstrates the possibility of generating genetically encoded SFTI‐based peptide libraries in live E. coli cells, and is a critical first step for developing in‐cell screening and directed evolution technologies using the cyclic peptide SFTI‐1 as a molecular scaffold. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 818–824, 2016.