bluuebunny/crossref_metadata_2025 huggingface dataset:
Flip‐avoiding interpolating surface registration for skull reconstruction
Authors: Xie Shudong , Leow Wee Kheng , Lee Hanjing , Lim Thiam Chye
Published: March 2018

Skull reconstruction is an important and challenging task in craniofacial surgery planning, forensic investigation and anthropological studies. Existing methods typically reconstruct approximating surfaces that regard corresponding points on the target skull as soft constraints, thus incurring non‐zero error even for non‐defective parts and high overall reconstruction error. This paper proposes a novel geometric reconstruction method that non‐rigidly registers an interpolating reference surface that regards corresponding target points as hard constraints, thus achieving low reconstruction error. To overcome the shortcoming of interpolating a surface, a flip‐avoiding method is used to detect and exclude conflicting hard constraints that would otherwise cause surface patches to flip and self‐intersect. Comprehensive test results show that our method is more accurate and robust than existing skull reconstruction methods. By incorporating symmetry constraints, it can produce more symmetric and normal results than other methods in reconstructing defective skulls with a large number of defects. It is robust against severe outliers such as radiation artifacts in computed tomography due to dental implants. In addition, test results also show that our method outperforms thin‐plate spline for model resampling, which enables the active shape model to yield more accurate reconstruction results. As the reconstruction accuracy of defective parts varies with the use of different reference models, we also study the implication of reference model selection for skull reconstruction.
A new approach for safe planning transfer using semi‐automatically adjustable instrument guides
Authors: Jeromin Sabine , Vossel Manuel , Rauchholz Christian , Billet Sylvain , Mueller Christian‐Andreas , Lavallée Stéphane , Radermacher Klaus , de la Fuente Mathias
Published: March 2018

Accurate planning transfer is a prerequisite for successful operative care. For different applications, diverse computer‐assisted systems have been developed and clinically evaluated. This paper presents the implementation and evaluation of a new modular concept. The approach is based on passive application specific kinematics that are semi‐automatically adjusted using a universal hand‐held computer controlled Smart Screw Driver.

The system was realized for pedicle screw instrumentation and evaluated according to IEC 60601‐1‐6 (usability engineering). The accuracies of the drill holes achieved were comparable with robotic approaches, while operation time and radiation were reduced compared with conventional operation techniques. The adjustment procedure has proven high learnability and user satisfaction.

The next step will be optimization of the kinematic structure and fixation to the patient in order to increase accuracies of planning transfer as well as evaluation of the overall system by medical staff in preclinical and clinical studies.
Analysis and optimization of bone machining for robotic orthopedic surgeries
Authors: Pell Derek J. , Soshi Masakazu
Published: March 2018

Background

Robot‐assisted joint replacement surgery is becoming increasingly more common worldwide, therefore it is important to characterize and improve the bone‐cutting mechanics of surgical tools.

Methods

Linear coefficients relating cutting force and chip thickness were derived for a surgical spindle. The cutting coefficients were integrated into an analytical simulation which calculated cutting forces, torque, and power consumption. An optimization experiment was performed. High speed video was taken at various tool parameter settings.

Results

Varying machining parameters resulted in lower cutting forces. The surgical spindle stalled at the current spindle speed used in surgery, but did not for the new, optimized conditions. Multiple anomalies were identified in the videos that confirmed observations from the cutting force data.

Conclusions

Improved surgical performance and accuracy were achieved using slower spindle speeds, decreased cutting depth, and increased feed rates, as well as improving motor torque to ensure a smooth cutting process.
Role of pituitary adenylate cyclase‐activating polypeptide in modulating hypothalamic‐pituitary system
Authors: Oride Aki , Kanasaki Haruhiko , Kyo Satoru
Published: March 2018

Background

Pituitary adenylate cyclase‐activating polypeptide (PACAP) is a multifunctional peptide that is isolated and identified from the ovine hypothalamus, whose effects and mechanisms have been elucidated in numerous studies. The PACAP and its receptor are widely expressed, not only in the hypothalamus but also in peripheral organs.

Methods

The studies on the role of PACAP in the hypothalamic‐pituitary system, including those by the authors, were summarized.

Results

In the pituitary gonadotrophs, PACAP increases the gonadotrophin α‐, luteinizing hormoneβ‐, and follicle‐stimulating hormone β‐subunit expression and the expression of gonadotropin‐releasing hormone (GnRH) receptor and its own receptor, PAC1R. Moreover, a low‐frequency GnRH pulse increases the expression of PACAP and PAC1R more than a high‐frequency GnRH pulse in the gonadotrophs. The PACAP stimulates prolactin synthesis and secretion and increases PAC1R in the lactotrophs. In the hypothalamus, PACAP increases the expression of the GnRH receptors, although it is unable to increase the expression of GnRH in the GnRH‐producing neurons.

Conclusion

The PACAP not only acts directly in each hormone‐producing cell, it possibly might regulate hormone synthesis via the expression of its own receptors or those of other hormones.
Three‐dimensional reconstruction of underwater objects using wide‐aperture imaging SONAR
Authors: Guerneve Thomas , Subr Kartic , Petillot Yvan
Published: March 2018

The estimation of the geometric structure of objects located underwater underpins a plethora of applications such as mapping shipwrecks for archaeology, monitoring the health of coral reefs, detecting faults in offshore oil rigs and pipelines, detection and identification of potential threats on the seabed, etc. Acoustic imaging is the most popular choice for underwater sensing. Underwater exploratory vehicles typically employ wide‐aperture Sound Navigation and Ranging (SONAR) imaging sensors. Although their wide aperture enables scouring large volumes of water ahead of them for obstacles, the resulting images produced are blurry due to integration over the aperture. Performing three‐dimensional (3D) reconstruction from this blurry data is notoriously difficult. This challenging inverse problem is further exacerbated by the presence of speckle noise and reverberations. The state‐of‐the‐art methods in 3D reconstruction from sonar either require bulky and expensive matrix‐arrays of sonar sensors or additional narrow‐aperture sensors. Due to its low footprint, the latter induces gaps between reconstructed scans. Avoiding such gaps requires slow and cumbersome scanning by the vehicles that carry the scanners. In this paper, we present two reconstruction methods enabling on‐site 3D reconstruction from imaging sonars of any aperture. The first of these presents an elegant linear formulation of the problem, as a blind deconvolution with a spatially varying kernel. The second method is a simple algorithmic approach for approximate reconstruction, using a nonlinear formulation. We demonstrate that our simple approximation algorithms perform 3D reconstruction directly from the data recorded by wide‐aperture systems, thus eliminating the need for multiple sensors to be mounted on underwater vehicles for this purpose. Additionally, we observe that the wide aperture may be exploited to improve the coverage of the reconstructed samples (on the scanned object's surface). We demonstrate the efficacy of our algorithms on simulated as well as real data acquired using two sensors, and we compare our work to the state of the art in sonar reconstruction. Finally, we show the employability of our reconstruction methods on field data gathered by an autonomous underwater vehicle.
Conservation impacts of a near real‐time forest monitoring and alert system for the tropics
Authors: Musinsky John , Tabor Karyn , Cano Carlos A. , Ledezma Juan Carlos , Mendoza Eddy , Rasolohery Andriambolantsoa , Sajudin Ermayanti R.
Published: March 2018

Near real‐time (NRT) forest monitoring and alert systems based on remotely sensed data are among the most recently developed tools to help manage and protect forest resources. The use of satellite and airborne remote sensing to quickly and accurately detect activities associated with deforestation has great potential for catalyzing local response teams responsible for assessing and interdicting threats to tropical forest ecosystems. To better understand the utility of NRT monitoring technologies in improving environmental protection and management, from 2008 to 2016 Conservation International conducted a series of surveys and interviews with users of these systems in four countries where wildfires threaten tropical forest ecosystems: Madagascar, Indonesia, Bolivia and Peru. Users reported that NRT forest monitoring systems made significant contributions to improving the ability of conservation and forest management organizations to respond to and reduce the impacts of fire, deforestation and other illegal or undesirable forest activity. Understanding the types of applications for which users successfully employed forest monitoring data, the challenges they faced in accessing, analyzing or disseminating these data, and the lessons learned from our attempts to develop and deploy NRT forest monitoring systems is useful to institutions interested in successfully incorporating NRT monitoring into their work.
Entrepreneurial orientation as a driver of brokerage in external networks: Exploring the effects of risk taking, proactivity, and innovativeness
Authors: Rank Olaf N. , Strenge Michael
Published: March 2018

Research Summary: In this article, we examine to what extent a firm's propensity to acquire brokerage positions in its external knowledge networks is driven by its entrepreneurial orientation. Specifically, we compare the influence of a firm's overall entrepreneurial orientation (EO) to the effects that the individual EO dimensions (i.e., risk taking, proactivity, and innovativeness) have on brokerage. Using a case study design, survey data was gathered from a company cluster in the German photonics industry. Applying a class of exponential random graph models, our results suggest that a firm's overall level of EO does not affect its propensity to obtain a brokerage position. In contrast, brokerage is positively influenced by a firm's willingness to take business‐related risks, whereas a pronounced orientation toward innovation seems to reduce brokerage.

Managerial Summary: While it has often been claimed that a pronounced orientation toward entrepreneurship helps firms succeed, the results of our study suggest that the individual dimensions of entrepreneurial orientation in fact differently influence the ability of firms to obtain brokerage positions in their external collaboration networks with partners. Specifically, obtaining brokerage positions seems to depend on the willingness of firms to take business‐related risks. In contrast to our theoretical considerations, we were unable to find empirical support for our assumption that proactivity would be a similarly important antecedent to network brokerage. Finally, firms should be careful with respect to an extensive orientation toward innovativeness, as they run the risk of neglecting the importance of an advantageous strategic position in their external networks.
Flexible Film Bulk Acoustic Wave Filters toward Radiofrequency Wireless Communication
Authors: Jiang Yuan , Zhao Yuan , Zhang Lin , Liu Bohua , Li Quanning , Zhang Menglun , Pang Wei
Published: March 2018

This paper presents a flexible radiofrequency filter with a central frequency of 2.4 GHz based on film bulk acoustic wave resonators (FBARs). The flexible filter consists of five air‐gap type FBARs, each comprised of an aluminum nitride piezoelectric thin film sandwiched between two thin‐film electrodes. By transfer printing the inorganic film structure from a silicon wafer to an ultrathin polyimide substrate, high electrical performance and mechanical flexibility are achieved. The filter has a peak insertion loss of −1.14 dB, a 3 dB bandwidth of 107 MHz, and a temperature coefficient of frequency of −27 ppm °C−1. The passband and roll‐off characteristics of the flexible filter are comparable with silicon‐based commercial products. No electrical performance degradation and mechanical failure occur under bending tests with a bending radius of 2.5 mm or after 100 bending cycles. The flexible FBAR filters are believed to be promising candidates for future flexible wireless communication systems.
A New Strategy for Maximizing the Storage Capacity of Lithium in Carbon Materials
Authors: Kang Jun , Kim Han‐Vin , Chae Seen‐Ae , Kim Kwang‐Ho
Published: March 2018

A novel strategy for maximizing the lithium storage capacity of carbon materials is reported. To redesign the interior structure, a large amount of Li, 4 wt%, is doped into the carbon during its synthesis. The Li‐doped carbon is subsequently annealed, during which the diffusion of Li induces a disordered structure, thereby generating many nanocavities. The diffused Li atoms aggregate into a superdense state within the carbon structure; when the Li agglomerates escape from the carbon during the delithiation process, new void spaces are created at their location. Thus, the interior of carbon is evacuated to form a new structure capable of storing a large amount of Li, realizing a high reversible capacity during charging. At a rate of 1 C, the average reversible capacity of the material is three times higher than that of commercial graphite, with a stable cycling performance over 300 cycles. This is a remarkably improved Li storage performance for pure carbon, without the need for the silicon, tin, or transition metal oxide, that are becoming popular as next‐generation materials. Therefore, this novel strategy can potentially aid in the design of high‐performance materials via better carbon material design and combinations with other types of materials.
Design and Realization of 3D Printed AFM Probes
Authors: Alsharif Nourin , Burkatovsky Anna , Lissandrello Charles , Jones Keith M. , White Alice E. , Brown Keith A.
Published: March 2018

Atomic force microscope (AFM) probes and AFM imaging by extension are the product of exceptionally refined silicon micromachining, but are also restricted by the limitations of these fabrication techniques. Here, the nanoscale additive manufacturing technique direct laser writing is explored as a method to print monolithic cantilevered probes for AFM. Not only are 3D printed probes found to function effectively for AFM, but they also confer several advantages, most notably the ability to image in intermittent contact mode with a bandwidth approximately ten times larger than analogous silicon probes. In addition, the arbitrary structural control afforded by 3D printing is found to enable programming the modal structure of the probe, a capability that can be useful in the context of resonantly amplifying nonlinear tip–sample interactions. Collectively, these results show that 3D printed probes complement those produced using conventional silicon micromachining and open the door to new imaging techniques.
MapReduce functions to remote sensing distributed data processing—Global vegetation drought monitoring as example
Authors: Zou Quan , Li Guoqing , Yu Wenyang
Published: March 2018

Global change models for different applications are developed, according to the principle of remote sensing technology. Data for these models are generally remote sensing image, which is multiplatform, multidimentional, multiband, and multisource. Moreover, such data may be in different parts of the world and perhaps up to terabyte or petabyte level. Therefore, a data‐intensive computing problem in the global change has emerged. Distributed computing infrastructures are suitable to store large‐scale datalike satellite images that have to be written only once and read frequently. The emergence of the cloud computing technology brings new information architecture, and global change models implemented in the cloud platform provide users with stable, effective, on‐demand cloud computing services. In this paper, the experiment is carried out on the cloud framework based on open cloud computing platform‐Hadoop. In addition, on this framework, it achieves a prototype example for monitoring global vegetation drought conditions. Oriented to a variety of remote sensing data, we propose an abstract data format to achieve the unified description of remote sensing data. The data abstraction is to discretize the multidimensional remote sensing data for easy‐distributed storage and computation. Using MapReduce paradigm, the complexity of remote sensing algorithms is resolved. Experimental results show that based on the parallel programming method, good scalability changing with the amount of processed data in the Hadoop distributed environment.
Effect of Solidification Pressure on Thermodynamic and Kinetic Parameters of 19Cr14Mn4Mo0.9N High Nitrogen Steel
Authors: Zhu Hong‐Chun , Jiang Zhou‐Hua , Li Hua‐Bing , Wang Peng‐Bo , Zhu Jun‐Hui
Published: March 2018

The influence of solidification pressure on the thermodynamic and kinetic parameters of 19Cr14Mn4Mo0.9N high nitrogen steel is clarified by Thermo‐Calc/DICTRA software, including phase diagram, solidification mode, liquidus/solidus temperature, nitrogen solubility, partition coefficient, diffusion coefficient, driving force for nucleation, and diffusion coefficient. On this basis, the effect of pressure on critical nucleation radius and nucleation rate is also revealed. In the calculated vertical sections of 19Cr14Mn4Mo‐xN alloy phase diagram, δ single‐phase region decreases, both γ single‐phase region and three‐phase region L + δ + γ increase with increasing pressure. Additionally, the reaction mode of solidification transition gradually turns from peritectic to eutectic reaction, and the solidification mode changes from FA to A mode. Increasing the partial pressure of nitrogen can suppress the formation of ferrite trap and increase nitrogen solubility. Meanwhile, the partition coefficients of C, N, Cr, and Si increase, that of Mn and Mo decreases, resulting in decrease of C, N, and Cr microsegregation and improvement of Si, Mn, and Mo microsegregation. Pressurization has a small impact on diffusion coefficients, but it obviously promote the driving force for produced phase (δ and γ) nucleation, this lead to the decrease of critical nucleation radius, improvement of nucleation rate, and grain refinement of 19Cr14Mn4Mo0.9N high nitrogen steel.
Effects of Pectin on the Pasting, Rheological, and Textural Properties of Lotus Root Starch
Authors: Zheng Jiong , Liu Min , Zhang Meixia , Kan Jianquan , Zhang Fusheng
Published: March 2018

To determine the effects of hydrocolloids on starch properties, high‐methoxyl pectin (HMP), and low‐methoxyl pectin (LMP) are mixed with lotus root starch (LRS). Changes in pasting, rheological, and textural properties, and microstructure of LRS composites are analyzed. LMP increases final viscosity, peak viscosity, breakdown viscosity, retrogradation value, and peak time of starch paste. HMP increases the peak time, but it decreases all other four pasting parameters. LMP increases shearing stress of LRS paste. The shearing stress of LRS paste is proportional to LMP concentration. With increasing consistency coefficient K, the flow behavior index n decreases. Opposite results are observed in HMP. In the LRS/HMP and LRS/LMP, G′ and G″ are positively correlated with LMP content, but these are negatively correlated with HMP. The minimum tanδ is achieved when LRS:LMP = 8:2, thereby indicating the strongest elasticity features. HMP can well inhibit short‐term retrogradation of LRS. Pectin decreases LRS hardness but increases cohesiveness, thereby forming a softer gel. Variations of adhesiveness and springiness are related with pectin type. According to SEM observation, the involvement of LMP destroys the original structure of LRS and forms a stable network structure, which is rare in the LRS/HMP system.
PGD2/PTGDR2 Signaling Restricts the Self-Renewal and Tumorigenesis of Gastric Cancer
Authors: Zhang Bin , Bie Qingli , Wu Peipei , Zhang Jie , You Benshuai , Shi Hui , Qian Hui , Xu Wenrong
Published: March 2018

The antitumor effect of prostaglandin D2 (PGD2) on gastric cancer (GC) has been known for decades. However, the mechanism of PGD2's control of GC growth is unclear. Cancer stem cells (CSCs) are implicated in tumor neovascularization, invasiveness, and therapeutic resistance. Herein, we discovered that signaling between PGD2 and its receptor (PTGDR2) has the ability to restrict the self-renewal of GC cells in vitro and suppress tumor growth and metastasis in vivo. To obtain these findings, we first determined that PGD2 synthase (L-PTGDS) and PTGDR2 expression were lower in GC tissues than adjacent tissues and was associated with the patients’ prognosis. Moreover, the expression of L-PTGDS and PTGDR2 was negatively correlated with the GC-CSC markers Sall4 and Lgr5 in GC tissues. Second, L-PTGDS and PTGDR2 expression were knocked down in CSC-like cells, resulting in enhanced expression of CSC markers and self-renewal ability. Direct PGD2 stimulation and L-PTGDS overexpression produced the opposite effect. Thirdly, PGD2 inhibited tumor growth and incidence rate in a subcutaneous tumor model and suppressed liver and mesenteric metastasis in a peritoneal metastasis model. Interfering with the expression of PTGDR2 reversed these effects in vivo. Last, a mechanistic study found that PGD2 inhibited STAT3 phosphorylation and nuclear expression. Further experiments revealed that the inhibitory effect of PGD2 on the expression of CSC markers disappeared after mutations were introduced into STAT3 phosphorylation (Thr705) site. In short, this study reveals a novel function of PGD2/PTGDR2 signaling on CSC regulation and provides a new way to control the development of GC.
Stem Cell Defect in Ubiquitin-Green Fluorescent Protein Mice Facilitates Engraftment of Lymphoid-Primed Hematopoietic Stem Cells
Authors: Faltusová Kateřina , Szikszai Katarína , Molík Martin , Linhartová Jana , Páral Petr , Šefc Luděk , Savvulidi Filipp , Nečas Emanuel
Published: March 2018

Transgenic mice expressing green fluorescent protein (GFP) are useful in transplantation experiments. When we used ubiquitin-GFP (UBC-GFP) transgenic mice to study the availability of niches for transplanted hematopoietic stem and progenitor cells, the results were strikingly different from the corresponding experiments that used congenic mice polymorphic in the CD45 antigen. Analysis of these unexpected results revealed that the hematopoiesis of UBC-GFP mice was outcompeted by the hematopoiesis of wild-type (WT) mice. Importantly, UBC-GFP mice engrafted the transplanted bone marrow of WT mice without conditioning. There was a significant bias toward lymphopoiesis in the WT branch of chimeric UBC-GFP/WT hematopoiesis. A fraction of immature Sca-1+ cells in the spleen of UBC-GFP mice expressed GFP at a very high level. The chimeric hematopoiesis was stable in the long term and also after transplantation to secondary recipient mice. The article thus identifies a specific defect in the hematopoiesis of UBC-GFP transgenic mice that compromises the lymphoid-primed hematopoietic stem cells in the bone marrow and spleen.
Optimized synthesis of cost‐effective, controllable oil system architectures for turbofan engines
Authors: Hambley Christopher J. , Jones Bryn L. , Griffin Ian , Mills Andrew R. , Kadirkamanathan Visakan
Published: March 2018

Turbofan oil systems are used to provide lubrication and cooling in the engine . There is an increasing interest in oil system architectures which utilize electric pumps and/or valves to give optimized control of flows to individual oil chambers, leading to improved thermal management of oil and lubrication efficiency. The challenges here lie in the trade‐off between increasing controllability and minimizing the addition of new components, which adds unwanted production and maintenance costs. This paper formulates the oil system architecture design as a constrained, multiobjective optimization problem. An architecture is described using a graph with nodes representing components and edges representing interconnections between components. A fixed set of nodes called the architecture template is provided as an input and the edges are optimized for a multicriteria objective function. A heuristic method for determining similarities between the different oil chamber flow requirements is presented. This is used in the optimization to evaluate the controllability objective based on the structure of the valve architecture. The methodology provides benefits to system designers by selecting cheaper architectures with fewer valves when the need to control oil chambers separately is small. The effect of manipulating the cost/controllability criteria weightings is investigated to show the impact on the resulting architecture.
Harnessing expert knowledge: Defining a Bayesian network decision model with limited data–Model structure for the vibration qualification problem
Authors: Rizzo Davinia B. , Blackburn Mark R.
Published: March 2018

As systems become more complex, systems engineers rely on experts to inform decisions. There are few experts and limited data in many complex new technologies. This challenges systems engineers as they strive to plan activities such as qualification in an environment where technical constraints are coupled with the traditional cost, risk, and schedule constraints. Bayesian network (BN) models provide a framework to aid systems engineers in planning qualification efforts with complex constraints by harnessing expert knowledge and incorporating technical factors. By quantifying causal factors, a BN model can provide data about the risk of implementing a decision supplemented with information on driving factors. This allows a systems engineer to make informed decisions and examine “what‐if” scenarios. This paper discusses a novel process developed to define a BN model structure based primarily on expert knowledge supplemented with extremely limited data (25 data sets or less). The model was developed to aid qualification decisions—specifically to predict the suitability of six degrees of freedom (6DOF) vibration testing for qualification. The process defined the model structure with expert knowledge in an unbiased manner. Validation during the process execution and of the model provided evidence the process may be an effective tool in harnessing expert knowledge for a BN model.
A historical perspective on systems engineering
Authors: Honour Eric C.
Published: March 2018

With 20 years of theSystems Engineeringjournal completed, this short article considers its impact on the discipline of systems engineering (SE) as a whole. It reviews the founding principles of this journal and assesses how well it has advanced those principles. In a broader sense, it also reviews 70 years of existence of the SE discipline and then looks ahead for its promises. After several decades of rapid growth, SE appears to have partially stagnated in the 1990s and 2000s in the face of process control pressures. The use of first principles has dwindled. Resurgence in the field, however, has been coincident with the time frame of this journal, as first principles are being redeveloped and new methods are arising. This journal successfully acts as a stimulus for that resurgence.
Can Single‐Pass Electrofishing Replace Three‐Pass Depletion for Population Trend Detection?
Authors: Hanks R. Daniel , Kanno Yoichiro , Rash Jacob M.
Published: March 2018

Since changes in climate and land use operate at broad spatial scales, efficient monitoring of temporal trends in fisheries resources over large geographic areas is vital to appropriate management. We compared the statistical power of single‐ versus three‐pass electrofishing surveys in detecting temporal trends of age‐1 and older Brook Trout Salvelinus fontinalis populations in western North Carolina. Empirical estimates of abundance and capture probabilities were obtained from annual three‐pass depletion surveys at 14 headwater stream sites between 2012 and 2017. The CVs in abundance averaged 26% (SD = 14.2%) across study sites, and the mean capture probability per pass was 0.72 (range = 0.57–0.84, SD = 0.09). Captures from single‐pass sampling and abundance estimates from three‐pass removal sampling were highly correlated (r2 = 0.98). In simulations, under the range of years sampled (5–25 years) and annual declines (2.5–7.5%) considered, the power to detect temporal trends was similar (∆ power < 0.1) between the two methods when five or more sites were monitored. An additional set of simulations with varying capture probabilities demonstrated that differences in power between the two methods increased as mean capture probabilities decreased (0.8, 0.5, and 0.2) accompanied by larger variation in capture probabilities among the samples, indicating results obtained with Brook Trout populations in North Carolina might not be applicable to other habitat types or species. Variation in fish abundance did not affect the difference in power between the two methods. Single‐pass electrofishing surveys can be an efficient survey method to monitor temporal population trends for habitat types and species characterized with high capture probabilities and low variation among samples. However, single‐pass data would not typically allow for inferences of capture probabilities and thus abundance. This can be problematic when environmental factors vary and when data sets collected using different protocols are compared. This trade‐off should be carefully considered when designing monitoring programs.
STEM career aspirations in Black, Hispanic, and White ninth‐grade students
Authors: Gottlieb Jessica J.
Published: March 2018

This study identifies factors that are significantly related to student intentions to enter science, technology, engineering, and mathematics (STEM) occupations by age 30, and examines how those factors differ across definitions of STEM occupation, educational attainment levels, and student demographics. Data from 2009 High School Longitudinal Study base year were used, and were analyzed using multinomial logistic regression. Expectancy‐value theory is the theoretical framework for this study. The findings from this study suggest that depending on the definition of STEM careers operationalized in the analysis, variation can be observed in the impact of gender, while the role of the expectancy‐value constructs remains largely consistent across multiple definitions of STEM careers. The results also suggest that while expectancy‐value constructs such as utility, interest, and attainment value are significantly related to the STEM career plans of White students, fewer significant relationships between expectancy‐value constructs and the STEM career plans of Black and Hispanic students were identified. Additionally, findings from this study raise questions about the extent to which STEM career choices at the sub‐bachelor's degree level can be understood as achievement‐related choices, and thus the extent to which expectancy‐value theory is a suitable framework for understanding those choices.
Development and performance analysis of dual‐input DC–DC converters for DC microgrid application
Authors: Athikkal Sivaprasad , Sundaramoorthy Kumaravel , Sankar Ashok
Published: March 2018

Hybridization of energy sources provides better reliability and flexibility for the power generation system. To integrate different sources, a suitable power electronic interface and a power management strategy are mandatory requirements. In this paper, two types of dual‐input–single‐output DC–DC converters to integrate two different V‐I characteristic sources for DC microgrid application are presented. The analysis of the converters based on the voltage and current stress of the power switches available in the circuit has been carried out for the appropriate selection of power switches. The software simulation of the proposed converters is performed on a MATLAB/Simulink platform in a detailed manner, and an experimental prototype of the presented converters has been built to validate the simulation results. The experimental results are well matched with the simulation results, which demonstrate the efficient performance of the converters. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Sliding mode variable structure control strategy of bearingless induction motor based on inverse system decoupling
Authors: Bu Wenshao , Zhang Xiaofeng , He Fangzhou
Published: March 2018

A bearingless induction motor is a multivariable, nonlinear and strong coupling object. To achieve its dynamic decoupling control with high performance and improve the system stability, a sliding mode variable structure (SMVS) control strategy based on inverse system decoupling is proposed. First, taking the stator current as the control variable, by means of inverse system method, the bearingless induction motor system is decoupled into four pseudolinear subsystems, including motor speed subsystem, rotor flux‐linkage subsystem and two radial displacement component subsystems. Then, according to the SMVS control theory, the regulator is designed for each subsystem. To overcome the chattering problem of the system, an exponential reaching law is introduced to the SMVS regulator; based on Lyapunov theory, system stability is analyzed. From the simulation experimental results, it is clear that the system has better dynamic decoupling control performance, a stronger ability to resist load disturbance and stronger robustness to the variation of motor parameters. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Design and simulation of a new model for air‐gapped current transformers
Authors: Wu Yahui , Dong Xinzhou , Mirsaeidi Sohrab
Published: March 2018

Current transformers (CTs) with air gaps in their iron cores are mainly applied in power systems to prevent saturation‐caused malfunctions of current‐based relays. However, performing reliable power system studies necessitates accurate modeling of air‐gapped CTs. This paper presents a new model for air‐gapped CTs based on the Preisach Theory, which has the ability to represent the role of air gaps of different lengths in the performance of a CT. The salient feature of this study in comparison with other published works is that it does not require measuring the magnetization curves of the air‐gapped core, which is often difficult. In order to validate the effectiveness of the proposed method, several simulations have been performed using PSCAD/EMTDC and MATLAB software packages. Simulation results indicate that the proposed model can accurately represent the characteristics of saturation as well as remanence of air‐gapped CTs. © 2018 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
Scaffolding Evidence‐Based Writing for English Learners in Three Steps
Authors: Lee Soyoung
Published: March 2018

Evidence‐based writing is a complex standard in the Common Core State Standards that has taken center stage in the writing curriculum. Students must demonstrate proficiency in making claims based on evidence and explain how the evidence supports their claim. This is a challenging task for all students, but for English learners, it can be especially overwhelming. The author describes a series of lessons that teachers can use to introduce evidence‐based writing in three steps to English learners. The author developed the three‐step lessons for use with English learners after observing teachers and students struggling with evidence‐based writing in linguistically diverse settings. The lessons incorporate literature on best practices in writing development for second‐language learners, and the descriptions of the lessons are supported with examples from a sixth‐grade English as a Second Language classroom.
Reconstruction of high‐resolution climate data over China from rainfall and snowfall records in the Qing Dynasty
Authors: Hao Zhixin , Yu Yingzhuo , Ge Quansheng , Zheng Jingyun
Published: March 2018

In recent years, researchers studying historical climates have given an increasing amount of attention to the Yu‐Xue‐Fen‐Cun record of the Qing Dynasty of China. These records play an important role in the quantitative reconstruction of the climate from the past 300 years in China due to their uniform recording formats and measurement methods. As a result of collective effort, methods for climate reconstruction are constantly improving, and regions with reconstructed high‐resolution historical climate data are expanding. This study reviews the features of the Yu‐Xue‐Fen‐Cun record and summarizes the progress and primary results achieved over the past 20 years. Studies showed that temperature variations over eastern China had three stages: a relatively cold phase in the 18th century, the coldest phase in the 19th century, and the warmest phase during and after the 20th century. However, the amplitudes between the maximum and minimum temperatures differed from 4.2 to 5.7 °C among different regions and sites. The variation in annual precipitation in North China showed an opposite phase to the Meiyu rainfall in the middle and lower reaches of the Yangtze River in the periods of 1736–1767, 1916–1948, and after 1955, and a consistent phase in the periods of 1792–1836 and 1845–1885. The rainband regularly moved away from South China in early May to the middle and lower reaches of the Yangtze River in mid‐June, and then finally arrived in North China in early July.

This article is categorized under:

Paleoclimates and Current Trends > Modern Climate Change
Harmonic balance Navier‐Stokes aerodynamic analysis of horizontal axis wind turbines in yawed wind
Authors: Drofelnik Jernej , Da Ronch Andrea , Campobasso Michele Sergio
Published: March 2018

Multimegawatt horizontal axis wind turbines often operate in yawed wind transients, in which the resulting periodic loads acting on blades, drive‐train, tower, and foundation adversely impact on fatigue life. Accurately predicting yawed wind turbine aerodynamics and resulting structural loads can be challenging and would require the use of computationally expensive high‐fidelity unsteady Navier‐Stokes computational fluid dynamics. The high computational cost of this approach can be significantly reduced by using a frequency‐domain framework. The paper summarizes the main features of the COSA harmonic balance Navier‐Stokes solver for the analysis of open rotor periodic flows, presents initial validation results on the basis of the analysis of the NREL Phase VI experiment, and it also provides a sample application to the analysis of a multimegawatt turbine in yawed wind. The reported analyses indicate that the harmonic balance solver determines the considered periodic flows from 30 to 50 times faster than the conventional time‐domain approach with negligible accuracy penalty to the latter.
A wind‐tunnel study of the wake development behind wind turbines over sinusoidal hills
Authors: Hyvärinen Ann , Lacagnina Giovanni , Segalini Antonio
Published: March 2018

In the present work, the wake development behind small‐scale wind turbines is studied when introducing local topography variations consisting of a series of sinusoidal hills. Additionally, wind‐tunnel tests with homogeneous and sheared turbulent inflows were performed to understand how shear and ambient turbulence influence the results. The scale of the wind‐turbine models was about 1000 times smaller than full‐size turbines, suggesting that the present results should only be qualitatively extrapolated to real‐field scenarios. Wind‐tunnel measurements were made by means of stereoscopic particle image velocimetry to characterize the flow velocity in planes perpendicular to the flow direction. Over flat terrain, the wind‐turbine wake was seen to slowly approach the ground while it propagated downstream. When introducing hilly terrain, the downward wake deflection was enhanced in response to flow variations induced by the hills, and the turbulent kinetic energy content in the wake increased because of the speed‐up seen over the hills. The combined wake observed behind 2 streamwise aligned turbines was more diffused and when introducing hills, it was more prone to deflect towards the ground compared to the wake behind an isolated turbine. Since wake interactions are common at sites with multiple turbines, this suggested that it is important to consider the local hill‐induced velocity variations when onshore wind farms are analysed. Differences in the flow fields were seen when introducing either homogeneous or sheared turbulent inflow conditions, emphasizing the importance of accounting for the prevailing turbulence conditions at a given wind‐farm site to accurately capture the downstream wake development.
Sound propagation through the wake flow of a hilltop wind turbine—A numerical study
Authors: Heimann Dietrich , Englberger Antonia , Schady Arthur
Published: March 2018

The sound propagation from a wind turbine situated on the top of a hill into the downwind domain is studied by numerical simulations for 13 cases with varying hill geometry and inflow conditions. The influence of the hill on the atmospheric flow and the wake due to the rotor are simulated by precursory large‐eddy simulations. In addition to the combined consideration of hill and turbine wake effects, these effects are also separately evaluated. The results show that placing the turbine on top of a hill leads to slightly lower sound levels on the downwind plane, although the wake alone supports downward refraction and tends to increase the sound impact near the ground at greater distance. Variations of the hill geometry and the inflow conditions do not have significant effects on the near‐ground sound levels in the downwind domain.
Silver Vanadyl(IV) ortho‐Pyrophosphate: Synthesis, Crystal Structure, and Characterization of the (V≡O)2+ Group
Authors: Wittich Knut , NejatyJahromy Yaser , Abdullin Dinar , Schiemann Olav , Karpov Andrey , Dobner Katharina , Rosowski Frank , Glaum Robert
Published: March 2018

Ag6(VIVO)2(PO4)2(P2O7) was obtained by reaction of Ag3PO4 and (VO)2P2O7 (sealed ampoule, 550 °C, 3 d). The crystal structure of the new mixed ortho‐pyrophosphate was determined from X‐ray single‐crystal data [Pnma, Z = 4, a = 12.759(3) Å, b = 17.340(4) Å, c = 6.418(1) Å, R1 = 0.071, wR2 = 0.184 for 3174 unique reflections with Fo > 4σ(Fo), 141 variables]. Ag+ ions are located in between layers [(VIVO)2(PO4)2(P2O7)]6–. Equilibrium relations of the new phosphate to neighboring phases were determined. The electronic structure of the (VIV≡O)2+ group was investigated by polarized electronic absorption spectroscopy (ν̃1a = 9450 cm–1, ν̃1b = 9950 cm–1, ν̃2 = 14750 cm–1), EPR spectroscopy [X‐ and Q‐band, powder and single crystal, orthorhombic crystal g‐tensor with g1 = 1.9445(3), g2 = 1.9521(3), g3 = 1.9695(3)], and magnetic measurements (powder, μexp/μB = 1.71, Θp = –1.7 K).
Rapid and stable production of 2,3-butanediol by an engineered Saccharomyces cerevisiae strain in a continuous airlift bioreactor
Authors: Yamada Ryosuke , Nishikawa Riru , Wakita Kazuki , Ogino Hiroyasu
Published: March 2018

Utilization of renewable feedstocks for the production of bio-based bulk chemicals, such as 2,3-butanediol (2,3-BDO), by engineered strains of the non-pathogenic yeast, Saccharomyces cerevisiae, has recently become an attractive option. In this study, to realize rapid production of 2,3-BDO, a flocculent, 2,3-BDO-producing S. cerevisiae strain YPH499/dPdAdG/BDN6-10/FLO1 was constructed from a previously developed 2,3-BDO-producing strain. Continuous 2,3-BDO fermentation was carried out by the flocculent strain in an airlift bioreactor. The strain consumed more than 90 g/L of glucose, which corresponded to 90% of the input, and stably produced more than 30 g/L of 2,3-BDO over 380 h. The maximum 2,3-BDO productivity was 7.64 g/L/h at a dilution rate of 0.200/h, which was higher than the values achieved by continuous fermentation using pathogenic bacteria in the previous reports. These results demonstrate that continuous 2,3-BDO fermentation with flocculent 2,3-BDO-producing S. cerevisiae is a promising strategy for practical 2,3-BDO production.
Correction to: Nickel hyperaccumulation in Antidesma montis‐silam: from herbarium discovery to collection in the native habitat
Authors: Nkrumah Philip Nti , Echevarria Guillaume , Erskine Peter Damian , van der Ent Antony
Published: March 2018

The article “Nickel hyperaccumulation in Antidesma montis‐silam: from herbarium discovery to collection in the native habitat”, written by Philip Nti Nkrumah, Guillaume Echevarria, Peter Damian Erskine, Antony van der Ent, was originally published electronically on the publisher's internet portal (currently SpringerLink) on 08 December 2017 without open access.
Can neuropsychological testing facilitate differential diagnosis between at-risk mental state (ARMS) for psychosis and adult attention-deficit/hyperactivity disorder (ADHD)?
Authors: Studerus Erich , Corbisiero Salvatore , Mazzariello Nadine , Ittig Sarah , Leanza Letizia , Egloff Laura , Beck Katharina , Heitz Ulrike , Andreou Christina , Stieglitz Rolf-Dieter , Riecher-Rössler Anita
Published: March 2018

Background:

Patients with an at-risk mental state (ARMS) for psychosis and patients with attention-deficit/hyperactivity disorder (ADHD) have many overlapping signs and symptoms and hence can be difficult to differentiate clinically. The aim of this study was to investigate whether the differential diagnosis between ARMS and adult ADHD could be improved by neuropsychological testing.

Methods:

168 ARMS patients, 123 adult ADHD patients and 109 healthy controls (HC) were recruited via specialized clinics of the University of Basel Psychiatric Hospital. Sustained attention and impulsivity were tested with the Continuous Performance Test, verbal learning and memory with the California Verbal Learning Test, and problem solving abilities with the Tower of Hanoi Task. Group differences in neuropsychological performance were analyzed using generalized linear models. Furthermore, to investigate whether adult ADHD and ARMS can be correctly classified based on the pattern of cognitive deficits, machine learning (i.e. random forests) was applied.

Results:

Compared to HC, both patient groups showed deficits in attention and impulsivity and verbal learning and memory. However, in adult ADHD patients the deficits were comparatively larger. Accordingly, a machine learning model predicted group membership based on the individual neurocognitive performance profile with good accuracy (AUC = 0.82).

Conclusions:

Our results are in line with current meta-analyses reporting that impairments in the domains of attention and verbal learning are of medium effect size in adult ADHD and of small effect size in ARMS patients and suggest that measures of these domains can be exploited to improve the differential diagnosis between adult ADHD and ARMS patients.