bluuebunny/crossref_metadata_2025 huggingface dataset:
Snapshot Compressive Multispectral Cameras
Authors: Arce Gonzalo R. , Rueda Hoover , Correa Claudia V. , Ramirez Ana , Arguello Henry
Published: February 2017

This article presents an overview of the fundamental optical phenomena behind compressive spectral imaging systems based on coded apertures. The key mathematical concepts embodying the sensing and reconstruction methods, the framework developed to design optimal coded apertures together with the computational spectral imaging strategies for classification, unmixing, and spectral selectivity purposes are also presented. Special attention is given for describing and discussing many practical aspects of compressive spectral imaging, including discretization models of the optical system, optimal parameters design, and physical limitations. The performance of the sensing strategies and computational methods is illustrated in this article with real data and imagery for different applications.
Evaluation of the performance of ionospheric models at solar maximum using COSMIC slant TEC measurements
Authors: Dymond K. F. , Coker C. , Metzler C. , McDonald S. E.
Published: February 2017

We report the results of a model validation study that assessed how well several ionospheric models captured the slant total electron content, especially at low latitudes near the equatorial ionization anomaly, where horizontal and vertical density gradients are large. We assessed NeQuick, IRI‐2007, IRI‐2012, SAMI‐3, and the Utah State University version of the Global Assimilation of Ionospheric Measurements (GAIM) model. We used slant total electron content measurements made by the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) constellation during 5 May to 20 June 2012 to test GAIM, NeQuick, IRI‐2007, and IRI‐2012 and during 1 October 2011 to 31 December 2011 to test SAMI‐3, as the SAMI‐3 model runs were not available for the 2012 time frame. We found that the GAIM data assimilation model showed the lowest biases, although all of the models typically agreed with the COSMIC measurements to ~8% in the worst case. One area of concern with all of the models was that the mean percentage difference between the COSMIC measurements and the calculated total electron content (TEC) showed significant scatter, >15% at the 1 sigma level; this was attributed to all of the models not capturing the density gradients near the equatorial ionization anomaly (EIA). All of the models underestimated the topside electron density and thus also the ionospheric slab thickness. Since ionospheric models are often validated using near‐vertical TEC measurements and the vertical TEC is the product of the electron density at the F region peak and the slab thickness, our results suggest that the peak density values in the models may be too high.
Global and regional fluxes of carbon from land use and land cover change 1850–2015
Authors: Houghton R. A. , Nassikas Alexander A.
Published: February 2017

The net flux of carbon from land use and land cover change (LULCC) is an important term in the global carbon balance. Here we report a new estimate of annual fluxes from 1850 to 2015, updating earlier analyses with new estimates of both historical and current rates of LULCC and including emissions from draining and burning of peatlands in Southeast Asia. For most of the 186 countries included we relied on data from Food and Agriculture Organization to document changes in the areas of croplands and pastures since 1960 and changes in the areas of forests and “other land” since 1990. For earlier years we used other sources of information. We used a bookkeeping model that prescribed changes in carbon density of vegetation and soils for 20 types of ecosystems and five land uses. The total net flux attributable to LULCC over the period 1850–2015 is calculated to have been 145 ± 16 Pg C (1 standard deviation). Most of the emissions were from the tropics (102 ± 5.8 Pg C), generally increasing over time to a maximum of 2.10 Pg C yr−1 in 1997. Outside the tropics emissions were roughly constant at 0.5 Pg C yr−1 until 1940, declined to zero around 1970, and then became negative. For the most recent decade (2006–2015) global net emissions from LULCC averaged 1.11 (±0.35) Pg C yr−1, consisting of a net source from the tropics (1.41 ± 0.17 Pg C yr−1), a net sink in northern midlatitudes (−0.28 ± 0.21 Pg C yr−1), and carbon neutrality in southern midlatitudes.
Reconstruction of coseismic slip from the 2015 Illapel earthquake using combined geodetic and tsunami waveform data
Authors: Williamson Amy , Newman Andrew , Cummins Phil
Published: February 2017

On 16 September 2015, a moment magnitude (Mw) 8.3 earthquake struck off the coast of central Chile, generating a large tsunami with nearby coastal wave heights observed on tide gauges in Chile and Peru of up to 4.7 m and distal observations of over 40 cm in the Kuril Islands across the Pacific Ocean. Through a transcoastal geodetic study, including tsunami time series recorded at open ocean pressure gauges, subaerial deformation observed through interferometric synthetic aperture radar from the Sentinel‐1 A satellite and continuous GPS, we identify the location and extent of coseismic slip. We find that most coseismic slip was concentrated in a patch immediately offshore, with little modeled slip near the trench. This result satisfies the tsunami waveforms measured in the deep ocean north of the rupture area, with wave heights up to 10 cm. While the event exhibits some features of a slow tsunami earthquake (moderately large tsunami and possible slow second‐stage rupture), our inversion results do not require substantial near‐trench rupture. However, the prevalence of large and shallow thrust along subduction megathrusts along central Chile raises the question of the likelihood of future such events and the implications for future hazardous tsunamigenic earthquakes.
Wind modulation of upwelling at the shelf‐break front off Patagonia: Observational evidence
Authors: Carranza M. M. , Gille S. T. , Piola A. R. , Charo M. , Romero S. I.
Published: February 2017

The South‐Atlantic Patagonian shelf is the largest chlorophyll‐a (Chl‐a) hot spot in Southern Ocean color images. While a persistent 1500 km long band of high Chl‐a along the shelf‐break front (SBF) is indicative of upwelling, the mechanisms that drive it are not entirely known. Along‐front wind oscillations can enhance upwelling and provide a nutrient pumping mechanism at shelf‐break fronts of western boundary currents. Here we assess wind‐induced upwelling at the SBF off Patagonia from daily satellite Chl‐a and winds, historical hydrographic observations, cross‐shelf Chl‐a fluorescence transects from two cruises, and in situ winds and water column structure from a mooring site. Satellite Chl‐a composites segregated by along‐front wind direction indicate that surface Chl‐a is enhanced at the SBF with southerly winds and suppressed with northerly winds. Northerly winds also result in enhanced Chl‐a further offshore (∼25–50 km). Synoptic transects as well as mean hydrographic sections segregated by along‐front winds show isopycnals tilted upward for southerly winds. Spring observations from the mooring also suggest that southerly winds destratify the water column and northerly winds restratify, in agreement with Ekman transport interacting with the front. Moreover, changes in water column temperature lag along‐front wind forcing by 2–4 days. Our results suggest that oscillations in along‐front winds, on timescales typical of atmospheric storms (2–10 days), can significantly modulate the upwelling and Chl‐a concentrations at the SBF off Patagonia, revealing the importance of wind‐induced upwelling for shelf‐slope exchange at shelf‐break fronts of western boundary currents.
Observations and a linear model of water level in an interconnected inlet‐bay system
Authors: Aretxabaleta Alfredo L. , Ganju Neil K. , Butman Bradford , Signell Richard P.
Published: February 2017

A system of barrier islands and back‐barrier bays occurs along southern Long Island, New York, and in many coastal areas worldwide. Characterizing the bay physical response to water level fluctuations is needed to understand flooding during extreme events and evaluate their relation to geomorphological changes. Offshore sea level is one of the main drivers of water level fluctuations in semienclosed back‐barrier bays. We analyzed observed water levels (October 2007 to November 2015) and developed analytical models to better understand bay water level along southern Long Island. An increase (∼0.02 m change in 0.17 m amplitude) in the dominant M2 tidal amplitude (containing the largest fraction of the variability) was observed in Great South Bay during mid‐2014. The observed changes in both tidal amplitude and bay water level transfer from offshore were related to the dredging of nearby inlets and possibly the changing size of a breach across Fire Island caused by Hurricane Sandy (after December 2012). The bay response was independent of the magnitude of the fluctuations (e.g., storms) at a specific frequency. An analytical model that incorporates bay and inlet dimensions reproduced the observed transfer function in Great South Bay and surrounding areas. The model predicts the transfer function in Moriches and Shinnecock bays where long‐term observations were not available. The model is a simplified tool to investigate changes in bay water level and enables the evaluation of future conditions and alternative geomorphological settings.
Slope‐induced tidal straining: Analysis of rotational effects
Authors: Schulz Kirstin , Endoh Takahiro , Umlauf Lars
Published: February 2017

Tidal straining is known to be an important factor for the generation of residual currents and transports of suspended matter in the coastal ocean. Recent modeling studies and field experiments have revealed a new type of “slope‐induced” tidal straining, in which the horizontal density gradient required for this process is induced by the presence of a slope rather than by river runoff (as in classical tidal straining). Slope‐induced tidal straining is investigated here with the help of an idealized numerical model, and results are compared to a recent data set from the East China Sea providing first direct observational evidence. The focus of this study is on the effect of rotation that was ignored in previous investigations. The model is shown to reproduce the key features of the observations, in particular the strain‐induced generation of unstable stratification in the bottom boundary layer during periods of upslope flow. Rotation effects are found to significantly reduce the upslope tidal pumping of suspended material and also give rise to a newly identified pumping mechanism that results in a vigorous transport of suspended material along the slope. It is shown that slope‐induced tidal straining is likely to be relevant for a wide range of oceanic slopes exposed to tidal motions.
Comparison of the ocean surface vector winds from atmospheric reanalysis and scatterometer‐based wind products over the Nordic Seas and the northern North Atlantic and their application for ocean modeling
Authors: Dukhovskoy Dmitry S. , Bourassa Mark A. , Petersen Guðrún Nína , Steffen John
Published: February 2017

Ocean surface vector wind fields from reanalysis data sets and scatterometer‐derived gridded products are analyzed over the Nordic Seas and the northern North Atlantic for the time period from 2000 to 2009. The data sets include the National Center for Environmental Prediction Reanalysis 2 (NCEPR2), Climate Forecast System Reanalysis (CFSR), Arctic System Reanalysis (ASR), Cross‐Calibrated Multiplatform (CCMP) wind product version 1.1 and recently released version 2.0, and QuikSCAT. The goal of the study is to assess discrepancies across the wind vector fields in the data sets and demonstrate possible implications of these differences for ocean modeling. Large‐scale and mesoscale characteristics of winds are compared at interannual, seasonal, and synoptic timescales. A cyclone tracking methodology is developed and applied to the wind fields to compare cyclone characteristics in the data sets. Additionally, the winds are evaluated against observations collected from meteorological buoys deployed in the Iceland and Irminger Seas. The agreement among the wind fields is better for longer time and larger spatial scales. The discrepancies are clearly apparent for synoptic timescales and mesoscales. CCMP, ASR, and CFSR show the closest overall agreement with each other. Substantial biases are found in the NCEPR2 winds. Numerical sensitivity experiments are conducted with a coupled ice‐ocean model forced by different wind fields. The experiments demonstrate differences in the net surface heat fluxes during storms. In the experiment forced by NCEPR2 winds, there are discrepancies in the large‐scale wind‐driven ocean dynamics compared to the other experiments.
The Atlantic Water boundary current north of Svalbard in late summer
Authors: Pérez‐Hernández M. Dolores , Pickart Robert S. , Pavlov Vladimir , Våge Kjetil , Ingvaldsen Randi , Sundfjord Arild , Renner Angelika H. H. , Torres Daniel J. , Erofeeva Svetlana Y.
Published: February 2017

Data from a shipboard hydrographic/velocity survey carried out in September 2013 of the region north of Svalbard in the Nansen Basin are analyzed to characterize the Atlantic Water (AW) boundary current as it flows eastward along the continental slope. Eight meridional transects across the current, spanning an alongstream distance of 180 km, allow for a detailed description of the current and the regional water masses. During the survey the winds were light and there was no pack‐ice. The mean section reveals that the boundary current was O(40 km) wide, surface‐intensified, with a maximum velocity of 20 cm/s. Its mean transport during the survey was 3.11 ± 0.33 Sv, of which 2.31 ± 0.29 Sv was AW. This suggests that the two branches of AW entering the Arctic Ocean via Fram Strait—the Yermak Plateau branch and the Svalbard branch—have largely combined into a single current by 30°E. At this location the boundary current meanders with a systematic change in its kinematic structure during offshore excursions. A potential vorticity analysis indicates that the flow is baroclinically unstable, consistent with previous observations of AW anticyclones offshore of the current as well as the presence of a near‐field cyclone in this data set. Our survey indicates that only a small portion of the boundary current is diverted into the Kvitøya Trough (0.17 ± 0.08 Sv) and that the AW temperature/salinity signal is quickly eroded within the trough.
Modeling thermal emissive bands radiometric calibration impact with application to AVHRR
Authors: Chang Tiejun , Wu Xiangqian , Weng Fuzhong
Published: February 2017

A novel analytical model of the calibration error impact on the Earth radiance measurement from thermal emissive bands of sensors is developed. The goal is to assess the impact of calibration errors, to evaluate those errors and to perform correction. This model is applied in the correction of bias in Advanced Very High Resolution Radiometer (AVHRR) channels 4 and 5 observed from the intercomparison with Infrared Atmospheric Sounding Interferometer measurements. A two‐step regression is used to separate the effects of calibration radiance errors from calibration coefficient errors. In the first step, the calibration radiance error, primarily due to internal calibration target (ICT) imperfections and temperature measurement error, is evaluated using the bias from selected Earth scenes with brightness temperatures close to the ICT temperature. The effects from the ICT imperfections and temperature measurement errors are analyzed collectively. The resulting estimation of the calibration radiance error is 0.30% for channel 4 and 0.33% for channel 5. After correcting the Earth scene radiance for these effects, the errors in the offset and nonlinear coefficient of instrument response are evaluated through the second step of the regression. A weighting function is used to account for the nonuniformity in the data distribution over the Earth radiance range. After the evaluation of the errors, removal of their effects can be achieved either through corrections of the calibration coefficients or correction of the measured radiance. The results are useful for the improvement of the AVHRR IR channel calibration algorithm. This model and two‐step regression approach can also be applied to other similar broadband thermal infrared radiometric sensors.
Closing the scale gap between land surface parameterizations and GCMs with a new scheme, SiB3‐Bins
Authors: Baker I. T. , Sellers P. J. , Denning A. S. , Medina I. , Kraus P. , Haynes K. D. , Biraud S. C.
Published: February 2017

The interaction of land with the atmosphere is sensitive to soil moisture (W). Evapotranspiration (ET) reacts to soil moisture in a nonlinear way, f(W), as soils dry from saturation to wilt point. This nonlinear behavior and the fact that soil moisture varies on scales as small as 1–10 m in nature, while numerical general circulation models (GCMs) have grid cell sizes on the order of 1 to 100s of kilometers, makes the calculation of grid cell‐average ET problematic. It is impractical to simulate the land in GCMs on the small scales seen in nature, so techniques have been developed to represent subgrid scale heterogeneity, including: (1) statistical‐dynamical representations of grid subelements of varying wetness, (2) relaxation of f(W), (3) moderating f(W) with approximations of catchment hydrology, (4) “tiling” the landscape into vegetation types, and (5) hyperresolution. Here we present an alternative method for representing subgrid variability in W, one proven in a conceptual framework where landscape‐scale W is represented as a series of “Bins” of increasing wetness from dry to saturated. The grid cell‐level f(W) is defined by the integral of the fractional area of the wetness bins and the value of f(W) associated with each. This approach accounts for the spatiotemporal dynamics of W. We implemented this approach in the SiB3 land surface parameterization and then evaluated its performance against a control, which assumes a horizontally uniform field of W. We demonstrate that the Bins method, with a physical basis, attenuates unrealistic jumps in model state and ET seen in the control runs.
Understanding watershed hydrogeochemistry: 2. Synchronized hydrological and geochemical processes drive stream chemostatic behavior
Authors: Li Li , Bao Chen , Sullivan Pamela L. , Brantley Susan , Shi Yuning , Duffy Christopher
Published: February 2017

Why do solute concentrations in streams remain largely constant while discharge varies by orders of magnitude? We used a new hydrological land surface and reactive transport code, RT‐Flux‐PIHM, to understand this long‐standing puzzle. We focus on the nonreactive chloride (Cl) and reactive magnesium (Mg) in the Susquehanna Shale Hills Critical Zone Observatory (SSHCZO). Simulation results show that stream discharge comes from surface runoff (Qs), soil lateral flow (QL), and deeper groundwater (QG), with QL contributing >70%. In the summer, when high evapotranspiration dries up and disconnects most of the watershed from the stream, Cl is trapped along planar hillslopes. Successive rainfalls connect the watershed and mobilize trapped Cl, which counteracts dilution effects brought about by high water storage (Vw) and maintains chemostasis. Similarly, the synchronous response of clay dissolution rates (Mg source) to hydrological conditions, maintained largely by a relatively constant ratio between “wetted” mineral surface area Aw and Vw, controls Mg chemostatic behavior. Sensitivity analysis indicates that cation exchange plays a secondary role in determining chemostasis compared to clay dissolution, although it does store an order‐of‐magnitude more Mg on exchange sites than soil water. Model simulations indicate that dilution (concentration decrease with increasing discharge) occurs only when mass influxes from soil lateral flow are negligible (e.g., via having low clay surface area) so that stream discharge is dominated by relatively constant mass fluxes from deep groundwater that are unresponsive to surface hydrological conditions.
A cellular automata‐based deterministic inversion algorithm for the characterization of linear structural heterogeneities
Authors: Fischer P. , Jardani A. , Lecoq N.
Published: February 2017

Inverse problem permits to map the subsurface properties from a few observed data. The inverse problem can be physically constrained by a priori information on the property distribution in order to limit the nonuniqueness of the solution. The geostatistical information is often chosen as a priori information; however, when the field properties present a spatial locally distributed high variability, the geostatistical approach becomes inefficient. Therefore, we propose a new method adapted for fields presenting linear structures (such as a fractured field). The Cellular Automata‐based Deterministic Inversion (CADI) method is, as far as we know when this paper is produced, the first inversion method which permits a deterministic inversion based on a Bayesian approach and using a dynamic optimization to generate different linear structures iteratively. The model is partitioned in cellular automaton subspaces, each one controlling a different zone of the model. A cellular automata subspace structures the properties of the model in two units (“structure” and “background”) and control their dispensing direction and their values. The partitioning of the model in subspaces permits to monitor a large‐scale structural model with only a few pilot‐parameters and to generate linear structures with local direction changes. Thereby, the algorithm can easily handle with large‐scale structures, and a sensitivity analysis is possible on these structural pilot‐parameters, which permits to considerably accelerate the optimization process in order to find the best structural geometry. The algorithm has been successfully tested on simple, to more complex, theoretical models with different inversion techniques by using seismic and hydraulic data.
Response of the lower troposphere to moisture intrusions into the Arctic
Authors: Johansson Erik , Devasthale Abhay , Tjernström Michael , Ekman Annica M. L. , L'Ecuyer Tristan
Published: February 2017

Water vapor intrusions (WVIs) explain a significant fraction of total moisture transport and its variability in the Arctic. WVIs can precondition the Arctic atmosphere for accelerated melting of sea ice through effects on surface longwave radiation. Using data from the NASA's A‐Train convoy of satellites to estimate the response of the lower troposphere to WVIs into the Arctic, we show that WVIs are associated with a surface warming of up to 5.3 K (±3.3 K) in winter and 2.3 K (±1.6 K) in summer, when averaged over the entire Arctic Ocean. The intrusions also lead to additional cloud radiative heating of up to 0.15 K/d via up to 30% increased cloudiness in the vertical and also cause a weakening of the stability in the lower troposphere. The lower tropospheric and surface warming during winter and spring highlights the importance of understanding contribution of preconditioning to accelerated ice melt in the Arctic.
Messenger
RNA
Splicing Signals
Authors: Cygan Kamil J , Taggart Allison J , Fairbrother William G , Mount Stephen M
Published: February 2017

Splicing is a post‐transcriptional processing step in which intervening sequences (introns) are excised and coding sequences (exons) are ligated together to create the mature mRNA (messenger ribonucleic acid) molecule. It is a sequential process that is facilitated by the information in the RNA (ribonucleic acid) sequence (splicing regulatory elements/signals) and numerous RNA‐binding proteins (trans factors). Splicing occurs through two biochemical steps, and is catalysed by a large ribonucleoprotein known as the spliceosome. The spliceosomal machinery recognises the core splicing signals and assembles in a stepwise fashion on the premRNA molecule. These signals include the obligate 5′ splice site, 3′ splice site and branch site sequence, as well as enhancer and silencer sequences which functionally interact with RNA binding proteins. A current research application in the field uses computational approaches to study splicing signals and predict the effect of single nucleotide variations on message processing.

Key Concepts

Splicing is a post‐transcriptional process in which certain sections of RNA (known as introns) are removed and other sections (known as exons) are ligated together, producing the mature mRNA molecule.

Splicing is catalysed by a large macromolecular machine known as the spliceosome.

The major elements required for splicing include the 5′ splice site (5′ss), the 3′ splice site (3′ss), the polypyrimidine tract and the branch site.

Most introns begin with a ‘GT’ sequence and end with an ‘AG’ sequence; however, there exists a class of intron with different boundary sequences that are recognised by a parallel spliceosome.

Outside of these major elements, there are additional enhancer and suppressor signals that interact with RNA‐binding proteins (RBPs) and affect splicing outcome.

Different combinations and positions of binding of RBPs can result in different splicing outcome.

Scientists do not yet have a complete understanding of all of the different splicing signals, and this topic is an area of active research.

Researchers are using computational machine learning approaches to predict the effects of sequence variation on splicing outcome.

Researchers are also using new methods of sequencing to determine which RNA sequences the RBPs are recognising.
Seabird Island Ecology
Authors: Anderson Wendy B , Mulder Christa PH , Ellis Julie C
Published: February 2017

Seabird islands house large colonies of seabirds that feed at sea but return to land to breed. Seabirds deposit large amounts of nutrients of marine origin onto islands; many species also disturb soil and vegetation during the building and maintenance of nests. Nutrient subsidies and physical disturbance by seabirds alter island soils and vegetation and modify plant and animal communities. Introduction of non‐native predators has resulted in population decreases or local extinction of many seabird species. Recent efforts at eradication of introduced seabird predators have been successful, but re‐establishment of seabirds and seabird island communities will likely take additional active restoration. Many other factors impact seabird populations such as overfishing, seabirds caught as by‐catch, increases in sea surface temperature, sea level rise, and various sorts of marine pollution, including plastics consumed by seabirds. These factors directly and indirectly affect the ecology of seabird islands.

Key Concepts

Seabirds deposit nutrients of marine origin in terrestrial environments.

Seabirds impose physical disturbance on soils and vegetation in the process of building and maintaining nests.

Seabird islands often house endemic and native plants and animals that are no longer found on the mainland.

The presence of seabirds selects for plants that are tolerant of high‐disturbance and high‐nutrient (i.e. nitrogen and phosphorus) conditions and that increase primary and secondary productivity.

Introduced mammalian predators have eradicated seabirds and other species on many seabird islands.

The reduction of seabird populations by introduced predators alters plant and animal communities and nutrient cycling.

Eradication of seabird predators is a necessary first step towards restoration of seabird islands.

Restoration of seabird islands often requires active management of seabirds, other animals and plant populations.

Protection of seabird islands will require international cooperation on land and at sea.

Several marine environmental issues impact seabird populations and thus also the island communities that are tightly associated with seabird presence.
Testing Children for Genetic Carrier Status
Authors: Vears Danya F
Published: February 2017

A number of studies have shown that some parents of children with a genetic condition are interested in knowing the carrier status of their other, unaffected children. The majority of international guidelines suggest that carrier testing in childhood is inappropriate and should be delayed until the child reaches the age of majority. These recommendations are often based on theoretical concerns and ethical considerations as there is a lack of evidence in the literature that performing carrier testing in childhood leads to any psychosocial harm. There is also evidence that carrier testing does take place in some circumstances. The different guidelines and position statements of professional bodies regarding carrier testing in childhood are reviewed. The views of both health professionals and parents about whether carrier testing is appropriate are described, along with the current evidence regarding the psychosocial impacts of performing carrier testing in children.

Key Concepts

The majority of international guidelines recommend against carrier testing in childhood.

Despite the guidelines, carrier testing does take place in some children in the context of an affected sibling.

Health professionals' willingness to test children for carrier status depends on a range of different factors, including the genetic condition.

Some parents want to know the carrier status of their unaffected children following the diagnosis of an affected child.

Parents express a range of motivations for desiring this information, although many want to communicate the carrier information to their child.

Currently there is no evidence of harm from performing carrier testing in childhood, although further research is warranted.
Conjugate Families of Distributions
Authors: Chakraborty Sayan , Maiti Tapabrata
Published: February 2017

The idea of a parameterized family of probability distributions conjugate to a given sampling process was proposed by Raiffa and Schlaifer in their influential monograph. Their work was based largely on exploring the benefits of conjugacy, which include mathematically tractable closed‐form expressions for many important quantities used in Bayesian inference and decision analysis. When statistical data are to be analyzed in Bayesian theory, a “prior” distribution must be chosen to model a person's belief concerning unknown parameters in the sampling process. The modeled uncertainty is that which exists prior to observation of the statistical data. There is no sense of innate a “priori” knowledge, or knowledge based on pure logical reasoning free of experience. Previous statistical data, for example, may be considered when choosing a prior distribution. If a conjugate family is rich enough, a prior distribution chosen from the family can provide a useful approximation to the actual considered opinion.
Small‐Area Estimation
Authors: Rao J. N. K.
Published: February 2017

This article provides an overview of methods for estimating small‐area means or totals when the area‐specific sample sizes are small. Methods studied include indirect methods based on implicit models and methods based on explicit models.
Stratified Sampling
Authors: Parsons Van L.
Published: February 2017

Stratified sampling is a probability sampling method that is implemented in sample surveys. The target population's elements are divided into distinct groups or strata where within each stratum the elements are similar to each other with respect to select characteristics of importance to the survey. Stratification is also used to increase the efficiency of a sample design with respect to survey costs and estimator precision. In this article, the foundations of stratified sampling are discussed in the framework of simple random sampling. Topics include the forming of the strata and optimal sample allocation among the strata. Practical implementation issues for stratified sampling are discussed and include systematic sampling, implicit stratification, and the construction of strata using modern software. The importance of using stratified sampling in practice is demonstrated by its usage in five major large‐scale health surveys conducted in the United States and the United Kingdom. For these surveys, details of the stratification and sampling methods are provided. Topics include multistage cluster sampling within strata and the use of systematic and probability proportional to size sampling.
Model‐Based Inference
Authors: Chambers Raymond L. , Clark Robert G.
Published: February 2017

A basic problem in survey sampling is that of inferring the value of the population totalTof a variableYusing sample data. A model‐based approach grounds this inference primarily on a statistical model for the population values ofY. Where appropriate, this model also allows for the variability associated with the sampling method.
Nearest Neighbor Methods: Overview with Examples
Authors: Dixon Philip M.
Published: February 2017

This article discusses nearest neighbor (NN) methods for the analysis of spatial point patterns and the analysis of field experiments. The distance from a point to its NN, or quantities derived from that distance, can be used to test whether the observed locations are a realization of a specific spatial point process. Edge effects, caused by recording data only within a bounded study area, can be important. When locations are marked (e.g., by the species of plant), NN methods provide information on the relationship between the marks. NN methods for field experiments can be used to model local spatial variability and improve estimates of treatment effects.
Women in Statistics
Authors: Golbeck Amanda L. , Ramírez Ramírez Lilia L. , Gel Yulia R.
Published: February 2017

Women's presence in the statistical sciences and other STEM disciplines made dramatic gains in the past few decades. However, there still exists the so‐called pyramid effect, that is, the number of women statisticians dramatically plummets as one climbs up the career ladder. One of the key constraints on this path is insufficient number of role models, that is, women statisticians and their successes tend to be “unseen.” We aim to bridge the gap on role models and provide a broad (nonexhaustive) overview on the impact of women in the history of statistical sciences.
Highly Efficient Three Primary Color Organic Single‐Crystal Light‐Emitting Devices with Balanced Carrier Injection and Transport
Authors: Ding Ran , Feng Jing , Dong Feng‐Xi , Zhou Wei , Liu Yang , Zhang Xu‐Lin , Wang Xue‐Peng , Fang Hong‐Hua , Xu Bin , Li Xian‐Bin , Wang Hai‐Yu , Hotta Shu , Sun Hong‐Bo
Published: February 2017

Organic single crystals have a great potential in the field of organic optoelectronics because of their advantages of high carrier mobility and high thermal stability. However, the application of the organic single crystals in light‐emitting devices (OLEDs) has been limited by single‐layered structure with unbalanced carrier injection and transport. Here, fabrication of a multilayered‐structure crystal‐based OLED constitutes a major step toward balanced carrier injection and transport by introducing an anodic buffer layer and electron transport layer into the device structure. Three primary color single‐crystal‐based OLEDs based on the multilayered structure and molecular doping exhibit a maximum luminance and current efficiency of 820 cd cm−2 and 0.9 cd A−1, respectively, which are the highest performance to date for organic single‐crystal‐based OLEDs. This work paves the way toward high‐performance organic optoelectronic devices based on the organic single crystals.
Nanoengineering Hybrid Supramolecular Multilayered Biomaterials Using Polysaccharides and Self‐Assembling Peptide Amphiphiles
Authors: Borges João , Sousa Maria P. , Cinar Goksu , Caridade Sofia G. , Guler Mustafa O. , Mano João F.
Published: February 2017

Developing complex supramolecular biomaterials through highly dynamic and reversible noncovalent interactions has attracted great attention from the scientific community aiming key biomedical and biotechnological applications, including tissue engineering, regenerative medicine, or drug delivery. In this study, the authors report the fabrication of hybrid supramolecular multilayered biomaterials, comprising high‐molecular‐weight biopolymers and oppositely charged low‐molecular‐weight peptide amphiphiles (PAs), through combination of self‐assembly and electrostatically driven layer‐by‐layer (LbL) assembly approach. Alginate, an anionic polysaccharide, is used to trigger the self‐assembling capability of positively charged PA and formation of 1D nanofiber networks. The LbL technology is further used to fabricate supramolecular multilayered biomaterials by repeating the alternate deposition of both molecules. The fabrication process is monitored by quartz crystal microbalance, revealing that both materials can be successfully combined to conceive stable supramolecular systems. The morphological properties of the systems are studied by advanced microscopy techniques, revealing the nanostructured dimensions and 1D nanofibrous network of the assembly formed by the two molecules. Enhanced C2C12 cell adhesion, proliferation, and differentiation are observed on nanostructures having PA as outermost layer. Such supramolecular biomaterials demonstrate to be innovative matrices for cell culture and hold great potential to be used in the near future as promising biomimetic supramolecular nanoplatforms for practical applications.
Ultrathin Nickel–Cobalt Phosphate 2D Nanosheets for Electrochemical Energy Storage under Aqueous/Solid‐State Electrolyte
Authors: Li Bing , Gu Peng , Feng Yongcheng , Zhang Guangxun , Huang Kesheng , Xue Huaiguo , Pang Huan
Published: February 2017

2D materials are ideal for constructing flexible electrochemical energy storage devices due to their great advantages of flexibility, thinness, and transparency. Here, a simple one‐step hydrothermal process is proposed for the synthesis of nickel–cobalt phosphate 2D nanosheets, and the structural influence on the pseudocapacitive performance of the obtained nickel–cobalt phosphate is investigated via electrochemical measurement. It is found that the ultrathin nickel–cobalt phosphate 2D nanosheets with an Ni/Co ratio of 4:5 show the best electrochemical performance for energy storage, and the maximum specific capacitance up to 1132.5 F g−1. More importantly, an aqueous and solid‐state flexible electrochemical energy storage device has been assembled. The aqueous device shows a high energy density of 32.5 Wh kg−1 at a power density of 0.6 kW kg−1, and the solid‐state device shows a high energy density of 35.8 Wh kg−1 at a power density of 0.7 kW kg−1. These excellent performances confirm that the nickel–cobalt phosphate 2D nanosheets are promising materials for applications in electrochemical energy storage devices.
A Lyotropic Liquid‐Crystal‐Based Assembly Avenue toward Highly Oriented Vanadium Pentoxide/Graphene Films for Flexible Energy Storage
Authors: Liu Haiqing , Tang Yanping , Wang Chi , Xu Zhixiao , Yang Chongqing , Huang Tao , Zhang Fan , Wu Dongqing , Feng Xinliang
Published: February 2017

A novel lyotropic liquid‐crystal (LC) based assembly strategy is developed for the first time, to fabricate composite films of vanadium pentoxide (V2O5) nanobelts and graphene oxide (GO) sheets, with highly oriented layered structures. It is found that similar lamellar LC phases can be simply established by V2O5 nanobelts alone or by a mixture of V2O5 nanobelts and GO nanosheets in their aqueous dispersions. More importantly, the LC phases can be retained with any proportion of V2O5 nanobelts and GO, which allows facile optimization of the ratio of each component in the resulting films. Named VrGO, composite films manifest high electrical conductivity, good mechanical stability, and excellent flexibility, which allow them to be utilized as high performance electrodes in flexible energy storage devices. As demonstrated in this work, the VrGO films containing 67 wt% V2O5 exhibit excellent capacitance of 166 F g−1 at 10 A g−1; superior to those of the previously reported composites of V2O5 and nanocarbon. Moreover, the VrGO film in flexible lithium ion batteries delivers a high capacity of 215 mAh g−1 at 0.1 A g−1; comparable to the best V2O5 based cathode materials.
Near‐Infrared Laser‐Triggered Nitric Oxide Nanogenerators for the Reversal of Multidrug Resistance in Cancer
Authors: Guo Ranran , Tian Ye , Wang Yajun , Yang Wuli
Published: February 2017

The potential therapeutic implications of nitric oxide (NO) for diverse diseases have been under consideration for years; however, the development of precisely controllable NO generation system with potential for clinical application has remained elusive. Herein, intelligent near‐infrared (NIR) laser‐triggered NO nanogenerators for the treatment of multidrug‐resistant (MDR) cancer are fabricated by integrating photothermal agents and heat‐sensitive NO donors into a single nanoparticle. Such nanogenerators can absorb 808 nm NIR photons and convert them into ample heat to trigger NO release. The generated NO molecules are demonstrated to successfully achieve multidrug‐resistance reversal by inhibiting the expression of P‐glycol protein. Consequently, the intracellular accumulation of doxorubicin is effectively increased, resulting in high toxicity to MDR cancer cells in vitro. By virtue of surface modification with targeting ligands, these nanoparticles are able to selectively accumulate in tumor tissue. The therapeutic effects of the nanogenerators are validated in a humanized MDR cancer model. The in vivo experiment indicates that the nanoparticles possess excellent tumor suppression functionality with few side effects upon NIR laser exposure. Therefore, this novel photothermal conversion‐based NO‐releasing platform is expected to be a potential alternative to clinical MDR cancer treatment and may provide insights with regard to other NO‐relevant medical treatments.
Tweezing of Magnetic and Non‐Magnetic Objects with Magnetic Fields
Authors: Timonen Jaakko V. I. , Grzybowski Bartosz A.
Published: February 2017

Although strong magnetic fields cannot be conveniently “focused” like light, modern microfabrication techniques enable preparation of microstructures with which the field gradients – and resulting magnetic forces – can be localized to very small dimensions. This ability provides the foundation for magnetic tweezers which in their classical variant can address magnetic targets. More recently, the so‐called negative magnetophoretic tweezers have also been developed which enable trapping and manipulations of completely nonmagnetic particles provided that they are suspended in a high‐magnetic‐susceptibility liquid. These two modes of magnetic tweezing are complimentary techniques tailorable for different types of applications. This Progress Report provides the theoretical basis for both modalities and illustrates their specific uses ranging from the manipulation of colloids in 2D and 3D, to trapping of living cells, control of cell function, experiments with single molecules, and more.
Cellulose Nanopaper and Nanofoam for Patient‐Tailored Drug Delivery
Authors: Löbmann Korbinian , Wohlert Jakob , Müllertz Anette , Wågberg Lars , Svagan Anna J.
Published: February 2017

The development of drug delivery systems with tailored drug release can be very challenging especially in the case of problematic drugs. To address this problem, pharmaceutical scientists frequently use different formulation approaches and excipients, often involving a complex and multistep preparation. In this study, new cellulose nanofiber (CNF) based drug formulations are developed that allow controlled drug release in a facile and fast way, i.e., by simply casting drug/CNF dispersions. Altering the processing conditions and utilizing the unique inherent chemicophysical properties of cationic CNF at interfaces, it is possible to produce either drug‐loaded CNF nanopapers (containing 21 or 51 wt% drug) or nanofoams (containing 21 wt% drug). The different formulations exhibit tailored release kinetics of the poorly water‐soluble model drug indomethacin from immediate (nanopapers, 10–20 min) to slow release (nanofoams, ≈24 h). The fast release, from the nanopapers, is a result of the interplay of the molecular and supramolecular structure of indomethacin in addition to observed enhanced intrinsic dissolution of drug in the presence of CNF. The slower drug release is achieved by changing the hierarchical structure, i.e., creating a CNF based foam (porosity 99.2 wt%), and the prolonged release is mainly due to an extended drug diffusion path.
Synthesis of 2‐Alkylaminoquinolines and 1,8‐Naphthyridines by Successive Ruthenium‐Catalyzed Dehydrogenative Annulation and N‐Alkylation Processes
Authors: Lv Wan , Xiong Biao , Jiang Huanfeng , Zhang Min
Published: February 2017

A new one‐pot synthetic protocol, enabling the facile access to 2‐alkylaminoquinolines and 1,8‐naphthyridines by successive ruthenium‐catalyzed dehydrogenative annulation and N‐alkylation processes, has been demonstrated. A series of 2‐aminoarylmethanols were efficiently converted in combination with different types of nitriles and alcohols into various desired products in moderate to excellent yields after isolation. Advantageously, the synthesis proceeds with high atom‐efficiency, broad substrate scope, operational simplicity, no need for external hydrogen sources and less environmentally benign halogenated reagents, thus offering a practical approach to access these two types of compounds that are currently difficult to prepare with the conventional methods.

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Global effects of income and income inequality on adult height and sexual dimorphism in height
Authors: Bogin Barry , Scheffler Christiane , Hermanussen Michael
Published: February 2017

Objectives

Average adult height of a population is considered a biomarker of the quality of the health environment and economic conditions. The causal relationships between height and income inequality are not well understood. We analyze data from 169 countries for national average heights of men and women and national‐level economic factors to test two hypotheses: (1) income inequality has a greater association with average adult height than does absolute income; and (2) neither income nor income inequality has an effect on sexual dimorphism in height.

Methods

Average height data come from the NCD‐RisC health risk factor collaboration. Economic indicators are derived from the World Bank data archive and include gross domestic product (GDP), Gross National Income per capita adjusted for personal purchasing power (GNI_PPP), and income equality assessed by the Gini coefficient calculated by the Wagstaff method.

Results

Hypothesis 1 is supported. Greater income equality is most predictive of average height for both sexes. GNI_PPP explains a significant, but smaller, amount of the variation. National GDP has no association with height. Hypothesis 2 is rejected. With greater average adult height there is greater sexual dimorphism.

Conclusions

Findings support a growing literature on the pernicious effects of inequality on growth in height and, by extension, on health. Gradients in height reflect gradients in social disadvantage. Inequality should be considered a pollutant that disempowers people from the resources needed for their own healthy growth and development and for the health and good growth of their children.