bluuebunny/crossref_metadata_2025 huggingface dataset:
BathyNet: A Deep Neural Network for Water Depth Mapping from Multispectral Aerial Images
Authors: Mandlburger Gottfried , Kölle Michael , Nübel Hannes , Soergel Uwe
Published: April 2021

Besides airborne laser bathymetry and multimedia photogrammetry, spectrally derived bathymetry provides a third optical method for deriving water depths. In this paper, we introduce BathyNet, an U-net like convolutional neural network, based on high-resolution, multispectral RGBC (red, green, blue, coastal blue) aerial images. The approach combines photogrammetric and radiometric methods: Preprocessing of the raw aerial images relies on strict ray tracing of the potentially oblique image rays, considering the intrinsic and extrinsic camera parameters. The actual depth estimation exploits the radiometric image content in a deep learning framework. 3D water surface and water bottom models derived from simultaneously captured laser bathymetry point clouds serve as reference and training data for both image preprocessing and actual depth estimation. As such, the approach highlights the benefits of jointly processing data from hybrid active and passive imaging sensors. The RGBC images and laser data of four groundwater supplied lakes around Augsburg, Germany, captured in April 2018 served as the basis for testing and validating the approach. With systematic depth biases less than 15 cm and a standard deviation of around 40 cm, the results satisfy the vertical accuracy limit Bc7 defined by the International Hydrographic Organization. Further improvements are anticipated by extending BathyNet to include a simultaneous semantic segmentation branch.
A novel hybrid predictive maintenance model based on clustering, smote and multi-layer perceptron neural network optimised with grey wolf algorithm
Authors: Buabeng Albert , Simons Anthony , Frempong Nana Kena , Ziggah Yao Yevenyo
Published: April 2021

Considering the complexities and challenges in the classification of multiclass and imbalanced fault conditions, this study explores the systematic combination of unsupervised and supervised learning by hybridising clustering (CLUST) and optimised multi-layer perceptron neural network with grey wolf algorithm (GWO-MLP). The hybrid technique was meticulously examined on a historical hydraulic system dataset by first, extracting and selecting the most significant statistical time-domain features. The selected features were then grouped into distinct clusters allowing for reduced computational complexity through a comparative study of four different and frequently used categories of unsupervised clustering algorithms in fault classification. The Synthetic Minority Over Sampling Technique (SMOTE) was then employed to balance the classes of the training samples from the various clusters which then served as inputs for training the supervised GWO-MLP. To validate the proposed hybrid technique (CLUST-SMOTE-GWO-MLP), it was compared with its distinct modifications (variants). The superiority of CLUST-SMOTE-GWO-MLP is demonstrated by outperforming all the distinct modifications in terms of test accuracy and seven other statistical performance evaluation metrics (error rate, sensitivity, specificity, precision, F score, Mathews Correlation Coefficient and geometric mean). The overall analysis indicates that the proposed CLUST-SMOTE-GWO-MLP is efficient and can be used to classify multiclass and imbalanced fault conditions.

Article Highlights

The issue of multiclass and imbalanced class outputs is addressed for improving predictive maintenance.

A multiclass fault classifier based on clustering and optimised multi-layer perceptron with grey wolf is proposed.

The robustness and feasibility of the proposed technique is validated on a complex hydraulic system dataset.
A quantum search decoder for natural language processing
Authors: Bausch Johannes , Subramanian Sathyawageeswar , Piddock Stephen
Published: April 2021

Probabilistic language models, e.g. those based on recurrent neural networks such as long short-term memory models (LSTMs), often face the problem of finding a high probability prediction from a sequence of random variables over a set of tokens. This is commonly addressed using a form of greedy decoding such as beam search, where a limited number of highest-likelihood paths (the beam width) of the decoder are kept, and at the end the maximum-likelihood path is chosen. In this work, we construct a quantum algorithm to find the globally optimal parse (i.e. for infinite beam width) with high constant success probability. When the input to the decoder follows a power law with exponentk> 0, our algorithm has runtimeRnf(R,k), whereRis the alphabet size,nthe input length; heref< 1/2, and$f\rightarrow 0$f→0exponentially fast with increasingk, hence making our algorithm always more than quadratically faster than its classical counterpart. We further modify our procedure to recover a finite beam width variant, which enables an even stronger empirical speedup while still retaining higher accuracy than possible classically. Finally, we apply this quantum beam search decoder to Mozilla’s implementation of Baidu’sDeepSpeechneural net, which we show to exhibit such a power law word rank frequency.
Habitat characteristics and life history explain reproductive seasonality in lagomorphs
Authors: Heldstab Sandra A.
Published: April 2021

Lagomorphs show extensive seasonal variation in their reproduction. However, the factors causing this large variation have so far mostly been investigated intraspecifically and therefore provide only some exemplary comparisons of lagomorph reproductive seasonality. The present study applies both a categorical description (birth season categories 1–5) and a quantitative measure (birth season length in months) to summarize the degree of birth seasonality in the wild of 69 lagomorph species. Using a comparative approach, I tested the influence of 13 factors, comprising six habitat, five life history and two allometric variables on birth season length in lagomorphs. Leporids mainly show non-seasonal birthing patterns with high intraspecific variation. Their opportunistic breeding strategy with high reproductive output and their large distribution areas across wide latitude and elevation ranges might be the reasons for this finding. Ochotonids reproduce strictly seasonally, likely because they live at northern latitudes, are high-altitude specialists, and occur in limited distribution areas. The most important factors associated with variation in lagomorph birth seasonality are mid-latitude, mean annual temperature and precipitation of a species’ geographical range and life history adaptations including fewer but larger litters in seasonal habitats. Birth seasons become shorter with increasing latitude, colder temperatures, and less precipitation, corresponding to the decreasing length of optimal environmental conditions. Leporid species with shorter breeding seasons force maternal resources into few large litters to maximise reproductive output while circumstances are favourable. Since allometric variables were only weakly associated with reproductive seasonality, life history adaptations and habitat characteristics determine birth seasonality in Lagomorpha.
Architecture and the Senses in the Italian Renaissance
Authors: Karmon David
Published: April 2021

This is the first study of Renaissance architecture as an immersive, multisensory experience that combines historical analysis with the evidence of first-hand accounts. Questioning the universalizing claims of contemporary architectural phenomenologists, David Karmon emphasizes the infinite variety of meanings produced through human interactions with the built environment. His book draws upon the close study of literary and visual sources to prove that early modern audiences paid sustained attention to the multisensory experience of the buildings and cities in which they lived. Through reconstructing the Renaissance understanding of the senses, we can better gauge how constant interaction with the built environment shaped daily practices and contributed to new forms of understanding. Architecture and the Senses in the Italian Renaissance offers a stimulating new approach to the study of Renaissance architecture and urbanism as a kind of 'experiential trigger' that shaped ways of both thinking and being in the world.
World Christianity and Indigenous Experience
Authors: Lindenfeld David
Published: April 2021

In this book, David Lindenfeld proposes a new dimension to the study of world history. Here, he explores the global expansion of Christianity since 1500 from the perspectives of the indigenous people who were affected by it, and helped change it, giving them active agency. Integrating the study of religion into world history, his volume surveys indigenous experience in colonial Latin America, Native North America, Africa and the African diaspora, the Middle East, India, East Asia, and the Pacific. Lindenfeld demonstrates how religion is closely interwoven with political, economic, and social history. Wide-ranging in scope, and offering a synoptic perspective of our interconnected world, Lindenfeld combines in-depth analysis of individual regions with comprehensive global coverage. He also provides a new vocabulary, with a spectrum ranging from resistance to acceptance and commitment to Christianity, that articulates the range and complexity of the indigenous conversion experience. Lindenfeld's cross-cultural reflections provide a compelling alternative to the Western narrative of progressive development.
Aircraft Aerodynamic Design with Computational Software
Authors: Rizzi Arthur , Oppelstrup Jesper
Published: April 2021

This modern text presents aerodynamic design of aircraft with realistic applications, using CFD software and guidance on its use. Tutorials, exercises, and mini-projects provided involve design of real aircraft, ranging from straight to swept to slender wings, from low speed to supersonic. Supported by online resources and supplements, this toolkit covers topics such as shape optimization to minimize drag and collaborative designing. Prepares seniors and first-year graduate students for design and analysis tasks in aerospace companies. In addition, it is a valuable resource for practicing engineers, aircraft designers, and entrepreneurial consultants.
CLARIFYING THE AGE OF INITIAL SETTLEMENT HORIZON IN THE MARIANA ISLANDS AND THE IMPACT OF HARD WATER: A RESPONSE TO CARSON (2020)
Authors: Petchey Fiona , Clark Geoffrey
Published: April 2021

This paper is a response to criticism by Carson (2020) concerning the age of the Unai Bapot archaeological site in the Mariana Islands. Of specific contention are supposed errors in the marine radiocarbon (14C) research reported by Petchey et al. (2017). According to Carson, this work produced marine reservoir offsets (ΔR) of “suspiciously wide variance from each other … and those results were incompatible with the site’s reported stratigraphy and dating (Carson 2008) as well as with other previously calculated marine reservoir corrections in the Mariana Islands (Carson 2010: 3).” This statement is misleading on all three points. Our reply discusses the problems encountered when dating shells from near-shore “marine” environments where terrestrial input, in particular hard water, may complicate date interpretation. We outline a cautionary tale relevant to any researcher using “marine” shell dates to develop regional archaeological chronologies in regions dominated by limestone.
Fourier transforms related to ζ(s)
Authors: Panzone Pablo A.
Published: April 2021

Using some formulas of S. Ramanujan, we compute in closed form the Fourier transform of functions related to Riemann zeta function $\zeta (s)=\sum \nolimits _{n=1}^{\infty } {1}/{n^{s}}$ and other Dirichlet series.
Predicting colostrum and calf blood components based on refractometry
Authors: Hue Do T. , Williams John L. , Petrovski Kiro , Bottema Cynthia D. K.
Published: April 2021

Provision of good quality colostrum is essential for the passive immunity and nutrition of newborn calves. In order to better predict the quality of colostrum and the transfer of passive immunity, the relationships between colostrum components and between calf serum components were examined in this study. Samples of bulk tank milk, colostrum pooled from several cows 0–4 d postpartum, and colostrum collected from individual cows twice daily for 3 d post-partum were compared. With the exception of fat percentage, there were strong correlations between the levels of the components in the pooled colostrum and in the individual cow colostrum collected 0–1 d postpartum. The correlations between total solids as measured by Brix refractometry and total protein, immunoglobulin G (IgG), lactose % and protein % in colostrum within 1 d postpartum and pooled colostrum were 0.92, 0.90, −0.88 and 0.98, respectively. These high correlations enabled these colostrum components to be accurately predicted from Brix % and therefore, the volume of colostrum required to feed neonate calves can be optimised based on Brix refractometry to avoid failure of passive immunity transfer. To assess whether the components obtained from colostrum were correlated in calf blood, newborn calves were separated from their dams before suckling and blood sampled before feeding (day 0), and on days 1 and 7, after receiving colostrum or milk twice a day. The correlations between glucose, total protein, IgG, and gamma-glutamyl transferase (GGT) levels in the calf blood were lower than the correlations observed between the colostrum components. The highest correlation was between serum protein measured by refractometer and serum IgG within one week postpartum. GGT activity was not a good indicator of serum IgG levels. However, serum protein refractometer measurements predicted serum IgG level with high accuracy, providing an on-farm test to determine that calves have received sufficient passive immunity and colostrum components.
Differential expression of angiotensin-converting enzyme-2 in human paranasal sinus mucosa in patients with chronic rhinosinusitis
Authors: Kawasumi T , Takeno S , Nishimura M , Ishino T , Ueda T , Hamamoto T , Takemoto K , Horibe Y
Published: April 2021

Objective

Severe acute respiratory syndrome coronavirus-2 uses angiotensin-converting enzyme-2 as a primary receptor for invasion. This study investigated angiotensin-converting enzyme-2 expression in the sinonasal mucosa of patients with chronic rhinosinusitis, as this could be linked to a susceptibility to severe acute respiratory syndrome coronavirus-2 infection.

Methods

Ethmoid sinus specimens were obtained from 27 patients with eosinophilic chronic rhinosinusitis, 18 with non-eosinophilic chronic rhinosinusitis and 18 controls. The angiotensin-converting enzyme-2 and other inflammatory cytokine and chemokine messenger RNA levels were assessed by quantitative reverse transcription polymerase chain reaction. Angiotensin-converting enzyme-2 positive cells were examined immunohistologically.

Results

The eosinophilic chronic rhinosinusitis patients showed a significant decrease in angiotensin-converting enzyme-2 messenger RNA expression. In the chronic rhinosinusitis patients, angiotensin-converting enzyme-2 messenger RNA levels were positively correlated with tumour necrosis factor-α and interleukin-1β (r = 0.4971 and r = 0.3082, respectively), and negatively correlated with eotaxin-3 (r = −0.2938). Angiotensin-converting enzyme-2 immunoreactivity was mainly localised in the ciliated epithelial cells.

Conclusion

Eosinophilic chronic rhinosinusitis patients with type 2 inflammation showed decreased angiotensin-converting enzyme-2 expression in their sinus mucosa. Angiotensin-converting enzyme-2 regulation was positively related to pro-inflammatory cytokines, especially tumour necrosis factor-α production, in chronic rhinosinusitis patients.
Cognitive determinants of community functioning and quality of life in homeless adults with mental illness: 6-year follow-up from the At Home/Chez Soi Study Toronto site
Authors: Gicas K. M. , Mejia-Lancheros C. , Nisenbaum R. , Wang R. , Hwang S. W. , Stergiopoulos V.
Published: April 2021

Background

High rates of physical and mental health comorbidities are associated with functional impairment among persons who are homeless. Cognitive dysfunction is common, but how it contributes to various functional outcomes in this population has not been well investigated. This study examines how cognition covaries with community functioning and subjective quality of life over a 6-year period while accounting for the effects of risk and protective factors.

Methods

Participants were 349 homeless adults (mean age = 39.8) recruited from the Toronto site of the At Home/Chez Soi study, a large Canadian randomized control trial of Housing First. Participants completed up to four clinical evaluations over 6 years. Factor scores were created to index verbal learning and memory (vLM) and processing speed-cognitive flexibility (PSCF). The primary outcomes were community functioning and subjective quality of life. Risk factors included lifetime homelessness, mental health diagnoses, medical comorbidity, and childhood adversity. Linear mixed-effects models were conducted to examine cognition-functional outcome associations over time, with resilience as a moderator.

Results

Better vLM (b = 0.787, p = 0.010) and PSCF (b = 1.66, p < 0.001) were associated with better community functioning, but not with quality of life. Resilience conferred a protective effect on subjective quality of life (b = 1.45, p = 0.011) but did not moderate outcomes.

Conclusions

Our findings suggest a need to consider the unique determinants of community functioning and quality of life among homeless adults. Cognition should be prioritized as a key intervention target within existing service delivery models to optimize long-term functional outcomes.
SIGNATURES OF MULTI-STATE SYSTEMS BASED ON A SERIES/PARALLEL/RECURRENT STRUCTURE OF MODULES
Authors: Yi He , Balakrishnan Narayanaswamy , Li Xiang
Published: April 2021

In this paper, we consider multi-state coherent systems that can be regarded as a series/parallel/recurrent connection of multi-state modules with binary/multi-state components. The multi-state (survival) signatures of such systems are presented in terms of multi-state (survival) signatures of related modules based on the structures. For a recurrent structure, the multi-state survival signature of the structure is also needed. The results established here are finally illustrated with a number of examples.
Climate change exposure of waterbird species in the African-Eurasian flyways
Authors: NAGY SZABOLCS , BREINER FRANK T. , ANAND MIRA , BUTCHART STUART H. M. , FLÖRKE MARTINA , FLUET-CHOUINARD ETIENNE , GUISAN ANTOINE , HILARIDES LAMMERT , JONES VICTORIA R. , KALYAKIN MIKHAIL , LEHNER BERNHARD , PEARCE-HIGGINS JAMES W. , VOLTZIT OLGA
Published: April 2021

Climate change presents a particularly complex challenge in the context of flyway scale conservation of migratory bird species as it requires coordinated action by multiple countries along these species’ migratory routes. Coordinating conservation responses requires understanding the vulnerability of species and their habitats to climate change at the flyway scale throughout each species’ annual cycle. To contribute to such understanding, we used species distribution models to assess the exposure to climate change of waterbird species that are the focus of the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA). We found that the species with the smallest proportion of their current range projected to be climatically suitable by 2050 (those whose distributions respond to changes in water availability but that do not perform synchronised migration) are dispersive species in the Afrotropical biogeographic realm, and migratory species in their breeding season, particularly Arctic breeding waders. These species also have the most limited availability of newly suitable areas. Projections for most other Palearctic migratory waterbird species suggest that losses of suitable areas in their current passage and wintering ranges may be largely offset by new areas becoming climatically suitable. The majority of migratory Palearctic waterbirds in the breeding season and Afrotropical waterbirds are widely dispersed with only a small proportion of their populations currently supported by ‘Critical Sites’ (i.e. sites that are either important for Globally Threatened Species or support 1% of the bioregional population of any waterbird species). This makes it unlikely that climate change adaptation measures focusing only on key sites will be sufficient to counter the predicted range losses. Therefore, climate change adaptation responses should also be implemented at the landscape scale for Afrotropical waterbirds and for breeding populations of Palearctic migrant waterbirds.
Asian-Americans Remain Low Utilizers of County Mental Health Services
Authors: Hoang Julia Luu , Lee Richard J.
Published: April 2021

The National Latino and Asian American Study (NLAAS, 2002–2003, n =2095) indicated that Asian-Americans (AA) use mental health services less frequently than the general population (8.6% vs. 17.95%). Even AA who have been diagnosed with mental health disorders use mental health services less frequently than their non-AA counterparts (34.1% versus 41.1%)2. AA in Riverside County count for 7.4% of the population, or about 181,356 individuals, according to the 2018 census estimates. The objective of the study is to examine and compare rates of utilization of mental health services by AA specifically in the Riverside County setting. This study utilizes data on patients’ ethnicity, age, gender, and diagnosis as collected annually by the Riverside County Department of Mental Health from the fiscal year of 2017–2018. It compares the prevalence of psychiatric disorders and the rate of utilization of mental health services by AA in the county to the data collected by the NLAAS. The total number of AA using mental health services in Riverside County is 669, which totals 1.73% of all individuals accessing the same services. The number of AA using mental health services represented 0.45% of the total AA population in Riverside County. AA in Riverside County are utilizing MH services even less than the national rates (0.45% vs 8.6% nationally from NLAAS data). The gap in care illustrated by these results exemplifies not only the disparity in utilization of MH services seen in this particular ethnic group, but portrays the stagnant results from Riverside County s attempts to address this issue. Possible reasons for the disparity include lack of access, stigma, recovery, migration, and a lack of culturally-competent care. A reimagined outreach initiative may help to better address this issue. Riverside County already has implemented an AA Task Force, holds health fairs at local churches in the communities, supports a UCR School of Medicine student-run free clinic, and is active in NAMI events.
SLOW-BURNING INSTABILITIES OF DUFORT–FRANKEL FINITE DIFFERENCING
Authors: GALLOWAY DAVID , IVERS DAVID
Published: April 2021

DuFort–Frankel averaging is a tactic to stabilize Richardson’s unstable three-level leapfrog timestepping scheme. By including the next time level in the right-hand-side evaluation, it is implicit, but it can be rearranged to give an explicit updating formula, thus apparently giving the best of both worlds. Textbooks prove unconditional stability for the heat equation, and extensive use on a variety of advection–diffusion equations has produced many useful results. Nonetheless, for some problems the scheme can fail in an interesting and surprising way, leading to instability at very long times. An analysis for a simple problem involving a pair of evolution equations that describe the spread of a rabies epidemic gives insight into how this occurs. An even simpler modified diffusion equation suffers from the same instability. Finally, the rabies problem is revisited and a stable method is found for a restricted range of parameter values, although no prescriptive recipe is known which selects this particular choice.
Inhibited Manganese Oxide Formation Hinders Cobalt Scavenging in the Ross Sea
Authors: Oldham Véronique E. , Chmiel Rebecca , Hansel Colleen M. , DiTullio Giacomo R. , Rao Deepa , Saito Mak
Published: April 2021

The Southern Ocean plays a critical role in regulating global uptake of atmospheric CO2. Trace elements like iron (Fe), cobalt (Co), and manganese (Mn) have been shown to modulate this primary productivity. Despite limited data, the vertical profiles for Mn, Fe, and Co in the Ross Sea show no evidence of scavenging, as typically observed in oceanic sites. This was previously attributed to low‐particle abundance and/or by mixing rates exceeding scavenging rates. Scavenging of some trace metals such as cobalt (Co) is thought to be largely governed by Mn (oxyhydr)oxides, assumed to be the main component of particulate Mn (pMn). However, our data show that pMn has an average oxidation state below 3 and with nondetectable Mn oxides. In addition, soluble Co profiles show no evidence of scavenging and Co uptake measurements show little Co uptake in the euphotic zone and low/no scavenging at depth. Instead, high concentrations of dissolved Mn (dMn, up to 90 nM), which is primarily complexed as Mn(III)‐L (up to 100%), are observed. Average dMn concentrations (10 ± 14 nM) are highest in bottom and surface waters. Manganese sources may include sediments and sea‐ice melt, as elevated dMn was measured in sea ice (12 nM) compared to its surrounding waters (3 nM), and sea ice dMn was 97% Mn(III)‐L. We contend that the lack of Co scavenging in the Ross Sea is due to a unique Mn redox cycle that favors the stabilization of Mn(III)‐complexes at the expense of Mn oxide particle formation.
Signal and Noise Separation From Satellite Magnetic Field Data Through Independent Component Analysis: Prospect of Magnetic Measurements Without Boom and Noise Source Information
Authors: Imajo S. , Nosé M. , Aida M. , Matsumoto H. , Higashio N. , Tokunaga T. , Matsuoka A.
Published: April 2021

We propose an application of the independent component analysis (ICA) to separate satellite‐induced time‐varying stray fields from magnetic field data obtained using onboard multiple magnetometers. The ICA is a method for estimating source signals at multiple sites so that the estimated source signals can become statistically independent of each other. Since stray field variations are statistically independent of external natural field variations, the ICA method is expected to separate the natural variations from stray fields. Thus, we applied the ICA to magnetic field data from the first Quasi‐Zenith Satellite, which has two triaxial fluxgate magnetometers, without using an extendable boom. First, we removed the long‐period trend from the original data to create detrended data. Then, we applied the FastICA algorithm to the detrended data and obtained six independent components (ICs). The stray fields were successfully separated into three ICs (noise ICs), and the natural signals were represented by the other three ICs (signal ICs). Finally, we restored the observed signals from the signal ICs, and confirmed that the natural phenomena variations were not altered by the processing step. We also proposed a selection method of the noise ICs using the C coefficient, which is the coefficient of the variance of the mixing vectors. There was a large difference in C between the ICs whose C coefficients are the largest third and fourth ones. Overall, these results demonstrate the possibility that the ICA method can support for boom‐less magnetic observations in future satellite missions.
Wind Variations in the Mesosphere and Lower Thermosphere Near 60°S Latitude During the 2019 Antarctic Sudden Stratospheric Warming
Authors: Liu Guiping , Janches Diego , Lieberman Ruth S. , Moffat‐Griffin Tracy , Mitchell Nicholas J. , Kim Jeong‐Han , Lee Changsup
Published: April 2021

Sudden stratospheric warmings (SSWs) could act as an important mediator in the vertical coupling of atmospheric regions and dramatic variations in the mesosphere and lower thermosphere (MLT) in response to SSWs have been documented. However, due to rare occurrences, SSWs in the Southern Hemisphere (SH) and their impacts on the MLT dynamics are not well understood. This study presents an analysis of MLT winds at ∼80–98 km altitudes measured by meteor radars located at Tierra del Fuego (53.7°S, 67.7°W), King Edward Point (54.3°S, 36.5°W) and King Sejong Station (62.2°S, 58.8°W) near 60°S latitude during the Antarctic winter. Eastward zonal winds from these stations are observed to decrease significantly near the peak date of the 2019 Antarctic SSW, and both zonal and meridional winds in 2019 exhibit considerable differences to the mean winds averaged over other non‐SSW years. A quasi 6‐day oscillation is observed at all three radar locations, being consistent with the presence of the westward propagating zonal wave‐1 planetary wave. The vertical wavelength of this wave is estimated to be ∼55 km, and the enhancement of the wave amplitude during this SSW is noticeable. Evidence of the interaction between the 6‐day wave and the semidiurnal diurnal tide is provided, which suggests a possible mechanism for SSWs to impact the upper atmosphere. This study reports the large‐scale variations in winds in the MLT region at SH midlatitudes to high latitudes in a key dynamic but largely unexplored latitudinal band in response to the 2019 Antarctic SSW.
Global Ionospheric Response to a Periodic Sequence of HSS/CIR Events During the 2007–2008 Solar Minimum
Authors: Negrea C. , Munteanu C. , Echim M. M.
Published: April 2021

In this study, we investigate the global ionospheric impact of high‐speed solar wind streams/corotating interaction regions (HSS/CIR). A series of 10 such events are identified between December 1, 2007 and April 29, 2008, characterized in the frequency domain by the main spectral peaks corresponding to 27, 13.5, 9, and 6.75 days. The spectra of solar wind magnetic field, speed, and proton density, as well as those of the geomagnetic indices AE and SYM‐H, are solely dominated by these features. By contrast, the ionospheric NmF2 and to a lesser extent the hmF2 spectra have a much more complex structure, with secondary peaks adding to or replacing the main ones. We argue that this is evidence of the nonlinear nature of the magnetosphere‐ionosphere coupling, highlighted particularly in the NmF2 ionospheric response. Additionally, we show that hmF2 is more closely correlated than NmF2 to all parameters describing the solar wind and geomagnetic activity. Finally, the ionospheric response shows a higher correlation with Bz than any other solar wind parameter, and higher with SYM‐H than AE, indicating that for the low‐frequency part of the spectrum, high‐latitude Joule heating and particle precipitation play a secondary role to that of prompt penetration electric fields in dictating the ionospheric response to geomagnetic activity, in the case of this sequence of HSS/CIR events.
Effects of Sediment‐Induced Density Gradients on the Estuarine Turbidity Maximum in the Yangtze Estuary
Authors: Zhu Chunyan , van Maren Dirk Sebastiaan , Guo Leicheng , Lin Jianliang , He Qing , Wang Zheng Bing
Published: April 2021

An estuarine turbidity maximum (ETM) is a region of elevated suspended sediment concentration (SSC) resulting from residual transport mechanisms driven by river flow, tides, and salinity‐induced density gradients (SalDG). However, in energetic and highly turbid environments such as the Yangtze Estuary, SedDG may also substantially contribute to the formation and maintenance of the ETM. Since this mechanism is relatively poorly understood, we develop a three‐dimensional model to explore the effect of SedDG on tidal dynamics and sediment transport. By running sensitivity simulations considering SalDG and/or SedDG, we conclude that the longitudinal SedDG leads to degeneration and landward movement of the ETM. Moreover, two effects of the vertical SedDG are identified to be responsible for sediment trapping: One by enhancing the vertical sediment concentration gradients, and another by additionally affecting hydrodynamics including the water levels, velocities and salinities. The longitudinal and vertical SedDG leads to seasonal and spring‐neap variations of upstream migration of the salt wedge: Vertical SedDG is more pronounced at neap tides in the wet season due to stronger stratification effects, whereas longitudinal SedDG is more pronounced at intermediate tides in the dry season due to weaker mixing and limited deposition. These findings imply that the SedDG contributes substantially to channel siltation and salt intrusion in highly turbid systems, and need to be accounted for when numerically modeling such phenomena.
Constraints on the Slip Distribution of the 1938 MW 8.3 Alaska Peninsula Earthquake From Tsunami Modeling
Authors: Freymueller Jeffrey T. , Suleimani Elena N. , Nicolsky Dmitry J.
Published: April 2021

We simulated tsunami propagation for several scenario slip distributions for the 1938 MW 8.3 earthquake along the Alaska Peninsula and compared these to the observed records at Unalaska/Dutch Harbor and Sitka. The Sitka record is sensitive to the depth of slip but not the along‐strike location and is fit best by slip at shallow depth. The Unalaska record is sensitive mainly to the along‐strike location of slip and is fit best by slip that is concentrated in the eastern part of the presumed 1938 rupture zone. The tsunami data show that the actual 1938 earthquake rupture zone was likely ∼200 km in length or shorter and had no slip near the Shumagin Islands or in the 2020 Simeonof earthquake's rupture zone. The rupture models that best predict the 1938 tsunami lie within the region of high present day slip deficit inferred from GPS.
Deep Neural Networks With Convolutional and LSTM Layers for SYM‐H and ASY‐H Forecasting
Authors: Collado‐Villaverde Armando , Muñoz Pablo , Cid Consuelo
Published: April 2021

Geomagnetic indices quantify the disturbance caused by the solar activity on a planetary scale or in particular regions of the Earth. Among them, the SYM‐H and ASY‐H indices represent the (longitudinally) symmetric and asymmetric geomagnetic disturbance of the horizontal component of the magnetic field at midlatitude with a 1‐min resolution. Their resolution, along with their relation to the solar wind parameters, makes the forecasting of the geomagnetic indices a problem that can be addressed through the use of Deep Learning, particularly using Deep Neural Networks (DNNs). In this work, we present two DNNs developed to forecast respectively the SYM‐H and ASY‐H indices. Both networks have been trained using the Interplanetary Magnetic Field (IMF) and the related index for the solar storms occurred in the last two solar cycles. As a result, the networks are able to accurately forecast the indices 2 h in advance, considering the IMF and indices values for the previous 200 min. The evaluation of both networks reveals a great forecasting precision, including good predictions for large storms that occurred during the solar cycle 23 and comparing with the persistence model for the period 2013–2020.
UTMOST, a single and cross-tissue TWAS (Transcriptome Wide Association Study), reveals new ASD (Autism Spectrum Disorder) associated genes
Authors: Rodriguez-Fontenla Cristina , Carracedo Angel
Published: April 2021

Autism spectrum disorders (ASD) is a complex neurodevelopmental disorder that may significantly impact on the affected individual’s life. Common variation (SNPs) could explain about 50% of ASD heritability. Despite this fact and the large size of the last GWAS meta-analysis, it is believed that hundreds of risk genes in ASD have yet to be discovered. New tools, such as TWAS (Transcriptome Wide Association Studies) which integrate tissue expression and genetic data, are a great approach to identify new ASD susceptibility genes. The main goal of this study is to use UTMOST with the publicly available summary statistics from the largest ASD GWAS meta-analysis as genetic input. In addition, an in silico biological characterization for the novel associated loci was performed. Our results have shown the association of 4 genes at the brain level (CIPC, PINX1, NKX2-2, and PTPRE) and have highlighted the association of NKX2-2, MANBA, ERI1, and MITF at the gastrointestinal level. The gastrointestinal associations are quite relevant given the well-established but unexplored relationship between ASD and gastrointestinal symptoms. Cross-tissue analysis has shown the association of NKX2-2 and BLK. UTMOST-associated genes together with their in silico biological characterization seems to point to different biological mechanisms underlying ASD etiology. Thus, it would not be restricted to brain tissue and it will involve the participation of other body tissues such as the gastrointestinal.
DNMT3A-mediated silence in ADAMTS9 expression is restored by RNF180 to inhibit viability and motility in gastric cancer cells
Authors: Sun Weilin , Ma Gang , Zhang Li , Wang Pengliang , Zhang Nannan , Wu Zizhen , Dong Yinping , Cai Fenglin , Chen Liqiao , Liu Huifang , liang Han , Deng Jingyu
Published: April 2021

ADAMTS9 belongs to the ADAMTS (a disintegrin and metalloproteinase with thrombospondin motifs) protein family, and its expression is frequently silenced due to promoter hypermethylation in various human cancers. However, the underlying mechanisms remain largely unknown. In this study, we investigated the inhibitory effects of ADAMTS9 on gastric cancer (GC) cells. We initially examined ADAMTS9 protein level in 135 GC and adjacent normal tissue pairs, showing that ADAMTS9 was strikingly decreased in the malignant specimens and patients with low ADAMTS9 expression exhibited more malignant phenotypes and poorer outcome. ADAMTS9 expression was restored in AGS and BGC-823 cells, which then markedly suppressed cellular viability and motility in vitro and in vivo. As ADAMTS9 was enriched in the nuclei of gastric mucosal cells, RNA-sequencing experiment showed that ADAMTS9 significantly altered gene expression profile in BGC-823 cells. Additionally, DNA methyltransferase 3α (DNMT3A) was identified to be responsible for the hypermethylation of ADAMTS9 promoter, and this methyltransferase was ubiquitinated by ring finger protein 180 (RNF180) and then subject to proteasome-mediated degradation. In conclusion, we uncovered RNF180/DNMT3A/ADAMTS9 axis in GC cells and showed how the signaling pathway affected GC cells.
Magnetically induced currents and aromaticity in ligand-stabilized Au and AuPt superatoms
Authors: López-Estrada Omar , Zuniga-Gutierrez Bernardo , Selenius Elli , Malola Sami , Häkkinen Hannu
Published: April 2021

Understanding magnetically induced currents (MICs) in aromatic or metallic nanostructures is crucial for interpreting local magnetic shielding and NMR data. Direct measurements of the induced currents have been successful only in a few planar molecules but their indirect effects are seen in NMR shifts of probe nuclei. Here, we have implemented a numerically efficient method to calculate gauge-including MICs in the formalism of auxiliary density functional theory. We analyze the currents in two experimentally synthesized gold-based, hydrogen-containing ligand-stabilized nanoclusters [HAu9(PPh3)8]2+ and [PtHAu8(PPh3)8]+. Both clusters have a similar octet configuration of Au(6s)-derived delocalized “superatomic” electrons. Surprisingly, Pt-doping in gold increases the diatropic response of the superatomic electrons to an external magnetic field and enhances the aromaticity of [PtHAu8(PPh3)8]+. This is manifested by a stronger shielding of the hydrogen proton in the metal core of the cluster as compared to [HAu9(PPh3)8]2+, causing a significant upfield shift in agreement with experimental proton NMR data measured for these two clusters. Our method allows the determination of local magnetic shielding properties for any component in large 3D nanostructures, opening the door for detailed interpretation of complex NMR spectra.
Intersystem crossing and exciton–defect coupling of spin defects in hexagonal boron nitride
Authors: Smart Tyler J. , Li Kejun , Xu Junqing , Ping Yuan
Published: April 2021

Despite the recognition of two-dimensional (2D) systems as emerging and scalable host materials of single-photon emitters or spin qubits, the uncontrolled, and undetermined chemical nature of these quantum defects has been a roadblock to further development. Leveraging the design of extrinsic defects can circumvent these persistent issues and provide an ultimate solution. Here, we established a complete theoretical framework to accurately and systematically design quantum defects in wide-bandgap 2D systems. With this approach, essential static and dynamical properties are equally considered for spin qubit discovery. In particular, many-body interactions such as defect–exciton couplings are vital for describing excited state properties of defects in ultrathin 2D systems. Meanwhile, nonradiative processes such as phonon-assisted decay and intersystem crossing rates require careful evaluation, which competes together with radiative processes. From a thorough screening of defects based on first-principles calculations, we identify promising single-photon emitters such as SiVV and spin qubits such as TiVV and MoVV in hexagonal boron nitride. This work provided a complete first-principles theoretical framework for defect design in 2D materials.
Variability in stem taper surface topography affects the degree of corrosion and fretting in total hip arthroplasty
Authors: Stockhausen Kilian Elia , Riedel Christoph , Belinski Alex Victoria , Rothe Dorothea , Gehrke Thorsten , Klebig Felix , Gebauer Matthias , Amling Michael , Citak Mustafa , Busse Björn
Published: April 2021

Degradation at the modular head-neck interface in total hip arthroplasty (THA) is predominately expressed in the form of corrosion and fretting, potentially causing peri-prosthetic failure by adverse reactions to metal debris. This retrieval study aimed to quantify variations in stem taper surface topographies and to assess the influence on the formation of corrosion and/or fretting in titanium alloy stem tapers combined with metal and ceramic heads. Four hip stem designs (Alloclassic, CLS, Bicontact and SL-Plus) were characterized using high-resolution 3D microscopy, and corrosion and fretting were rated using the Goldberg scoring scheme. Quantification of the taper surface topographies revealed a high variability in surface characteristics between threaded stem tapers: Alloclassic and CLS tapers feature deeply threaded trapezoid-shaped profiles with thread heights over 65 µm. The sawtooth-shaped Bicontact and triangular SL-Plus taper are characterized by low thread heights below 14 µm. Significantly lower corrosion and fretting scores were observed in lightly threaded compared to deeply threaded tapers in ceramic head combinations. No significant differences in corrosion or fretting scores with thread height were found in pairings with metal heads. Understanding the relationship between stem taper surface topography and the formation of corrosion and fretting could help to improve the performance of modern THAs and lead to longer-lasting clinical results.
Future rice farming threatened by drought in the Lower Mekong Basin
Authors: Kang Hyunwoo , Sridhar Venkataramana , Mainuddin Mohammed , Trung Le Duc
Published: April 2021

The Lower Mekong River basin (LMB) has experienced droughts in recent decades, causing detrimental economic losses and food security conundrums. This study quantified the impact of climate change on drought, and rainfed rice production in the LMB. The Soil and Water Assessment Tool (SWAT) and AquaCrop models were used to evaluate long-term drought indices and rainfed rice yields under historical and future climate conditions (1954–2099) with four climate models and two emission scenarios (RCP 4.5 and RCP8.5) from the Coupled Model Intercomparison Project Phase 5 (CMIP5). We found that rice yield might increase (24–43%) due to the elevated levels of atmospheric CO2 concentration (+ 34.3 to + 121.9%) and increases in precipitation. Contrastingly, considerable decreases in rice yield up to 1.5 ton/ha in the Vietnam Central High Plain (VCHP) region could be expected resulting from reduced precipitation by about 34% during drought years. To avert any major food crisis, an expansion of irrigation areas could be required to compensate for the expected reduction in rice yields. We conclude that a framework combining hydrology and crop models to assess climate change impacts on food production is key to develop adaptation strategies in the future.
High precise dating on the variation of the Asian summer monsoon since 37 ka BP
Authors: Li Ting-Yong , Wu Yao , Shen Chuan-Chou , Li Jun-Yun , Chiang Hong-Wei , Lin Ke , Tan Liang-Cheng , Jiang Xiu-Yang , Cheng Hai , Edwards R. Lawrence
Published: April 2021

Comprehensive comparison of paleoclimate change based on records constrained by precise chronology and high-resolution is essential to explore the correlation and interaction within earth climate systems. Here, we propose a new stalagmite-based multidecadal resolved Asian summer monsoon (ASM) record spanning the past thirty-seven thousand years (ka BP, beforead1950) from Furong Cave, southwestern China. This record is consistent with the published Chinese stalagmite sequences and shows that the dominant controls of the ASM dynamics include not only insolation and solar activity but also suborbital-scale hydroclimate events in the high latitudes of the northern hemisphere, such as the Heinrich events, Bølling-Allerød (BA), and Younger Dryas (YD). Benefit from the unprecedented accurate chronology, the timings of these events are precisely dated, with uncertainties of, at most, 40 years (2σ). The onset of the weak ASM during the YD began at 12.92 ka BP and lasted for 430 years. The occurrence of the 200-yr Older Dryas during the BA period was dated from 13.87 to 14.06 ka BP. The durations of the three Heinrich (H) events, H1, H2, and H3, are 14.33–18.29, 23.77–24.48, and 28.98–30.46 ka BP, respectively. Furong record shows surprisingly variable onset transitions of 980, 210, and 40 years for the corresponding weak ASM events. These discrepancies suggest different influences of the H events on ASM dynamics. During the periods of H 1–3, the obvious difference between our Furong record and NGRIP δ18O record indicated the decoupling correlation between the mid-low latitudes and high latitudes. On the other hand, synchronous climate change in high and low latitudes suggests another possibility which different to the dominant role of Northern high latitudes in triggering global climate change. Our high quality records also indicate a plausible different correlation between the high and mid-low latitudes under glacial and inter-glacial background, especially for the ASM regimes.