bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of detection terminal for active millimetre‐wave imaging
Authors: Mei Hanxue , Wang Jinbang , Zhang Tao , Liu Zhiguo
Published: August 2019

The diode is used as the detection unit to receive the millimetre‐wave signal directly. A circuit is made with an operational amplifier OP27 to amplify the signal. The magnification of the OP27 circuit is stable at 100 <100 kHz. The performances of the detection terminal and the low‐pass filter amplifying circuit are compared in different distance between the source and the diode with a polarisation angle of 70°. The result shows good sensitivity of the detection terminal in active millimetre‐wave imaging. A one‐dimensional imaging test on the detection terminal is performed.
General space‐time clutter model for multi‐channel airborne radar
Authors: Xinzhe Li , Wenchong Xie , Yongliang Wang , Jie Ma
Published: August 2019

Ground clutter of looking‐down airborne radar is spread in Doppler because of the platform motion, and thus the interested moving targets may be masked by the ground clutter. In order to enhance the performance of clutter suppression, the clutter characteristics should be analysed in detail. So here, a general clutter model which suits for the conventional‐phased array radar, multiple‐input‐multiple‐output (MIMO) radar, and hybrid MIMO‐phased array radar, all with arbitrary array shape, whether in monostatic or bistatic applications, is developed. Clutter characteristics under two typical scenarios are presented by simulation examples, simultaneously; the effectiveness of the general clutter model is demonstrated.
Features of multi‐fractal structure of high‐altitude lightning discharges in the ionosphere: elves, jets, sprites
Authors: Potapov Alexander A. , Cerman Vitality A.
Published: August 2019

Physical properties of elves, jets and sprites, which are the most interesting types of high‐attitude discharges in the atmosphere, are considered in the work. The results of researches of its fractal characteristics are presented. The obtained results give grounds for a deeper insight of development, relaxation of such atmosphere processes and taking into account of their action on radio systems.
Relations between phenomenological and physical parameters in the hot coronae of AGNs computed with the MoCA code
Authors: Middei R. , Bianchi S. , Marinucci A. , Matt G. , Petrucci P.-O. , Tamborra F. , Tortosa A.
Published: August 2019

Context. The primary X-ray emission in active galactic nuclei (AGNs) is widely believed to be due to Comptonisation of the thermal radiation from the accretion disc in a corona of hot electrons. The resulting spectra can, in first approximation, be modelled with a cut-off power law, the photon index and the high-energy roll-over encoding information on the physical properties of the X ray emitting region. The photon index and the high-energy curvature of AGNs (Γ, Ec) have been largely studied since the launch of X-ray satellites operating above 10 keV. However, high-precision measurements of these two observables have only been obtained in recent years thanks to the unprecedented sensitivity of NuSTAR up to 79 keV.

Aims. We aim at deriving relations between Γ, Ec phenomenological parameters and the intrinsic properties of the X-ray-emitting region (the hot corona), namely the optical depth and temperature.

Methods. We use MoCA (Monte Carlo code for Comptonisation in Astrophysics) to produce synthetic spectra for the case of an AGN with MBH = 1.5 × 108 M⊙ and ṁ = 0.1 and then compared them with the widely used power-law model with an exponential high-energy cutoff.

Results. We provide phenomenological relations relating Γ and Ec with the opacity and temperature of the coronal electrons for the case of spherical and slab-like coronae. These relations give origin to a well defined parameter space which fully contains the observed values. Exploiting the increasing number of high-energy cut-offs quoted in the literature, we report on the comparison of physical quantities obtained using MoCA with those estimated using commonly adopted spectral Comptonisation models. Finally, we discuss the negligible impact of different black hole masses and accretion rates on the inferred relations.
A possibilistic optimization over an integer efficient set within a fuzzy environment
Authors: Menni Assia , Chaabane Djamal
Published: August 2019

Optimizing a linear function over the efficient set of a Multiple Objective Integer Linear Programming (MOILP) problem is known as a difficult problem to deal with, since a discrete efficient set is generally not convex and not explicitly known. Such problem becomes more and more difficult when parameters are defined with uncertainty. In this work, we deal with problems of this type for which parameters are imprecise and are assumed to be trapezoidal fuzzy numbers. The method is based on possibility and necessity measures introduced in the literature by D. Dubois and H. Prade.
Harninkontinenz bei geriatrischen Patienten: Verhaltensintervention, Toilettentraining und physiotherapeutische Interventionen
Authors: Becher Klaus , Bojack Barbara , Ege Sigrid , von der Heide Silke , Kirschner-Hermanns Ruth , Wiedemann Andreas
Published: August 2019

Einleitung 1/2019 wurde ein update der seit 2005 in AWMF eingestellten und fortlaufend aktualisierten Leitlinie „Harninkontinenz bei geriatrischen Patienten – Diagnostik und Therapie“ durch die interdisziplinäre Arbeitsgruppe „Harninkontinenz“ der Deutschen Gesellschaft für Geriatrie (DGG) publiziert. Aus dieser Leitlinie, die als offizielle Leitlinie DGG akkreditiert ist, stellt der vorliegende Artikel das Kapitel „Verhaltensintervention, Toilettentraining, physiotherapeutische Maßnahmen“ dar.

Methodik In einem strukturierten Bewertungsprozess identifizierte eine Literaturrecherche zunächst die vorhandene Literatur im Kontext des „geriatrischen Patienten“, wie er als zumeist über 70jährig und multimorbid oder über 80jährig durch die Fachgesellschaften definiert ist. Primäre Berücksichtigung fanden randomisierte, doppelblinde, plazebokontrollierte Studien sowie bereits vorhandene Leitlinien zum Thema. Wo keine solchen Untersuchungen vorlagen oder aus methodischen Gründen prinzipiell nicht durchführbar sind, wurden auch Publikationen anderen Designs (nicht randomisierte Untersuchungen, Fallkontrollstudien) zur Leitlinienerstellung herangezogen. Die daraus resultierenden Leitlinienempfehlungen wurden in einem strukturierten Abstimmungsprozess unterzogen; das Ergebnis ist in Prozent der zustimmenden Gruppenmitgliedern angegeben.

Ergebnisse Vor dem Hintergrund der Polypharmazie mit ihren Medikamenteninteraktionen und der besonderen Vulnerabilität des hochbetagten, geriatrischen Patienten sind nicht nicht-pharmakologische und nicht-operative Interventionen besonders wichtig. Diese bedürfen jedoch ein Mindestmaß an Compliance und Restmobilität. Vor diesem Hintergrund wurden Verhaltensinterventionen wie Gewichtsabnahme, Flüssigkeitsmanagement, Diuretikaeinsatz, Stuhlregulierung und Toilettentraining sowie aktive und passive physiotherapeutische Maßnahmen im Hinblick auf ihre Wirkung und Anwendbarkeit bei geriatrischen Patienten überprüft und bewertet.

Schlussfolgerungen Verhaltensinterventionen, Toilettentraining und physiotherapeutische Maßnahmen sind besonders vor dem Hintergrund der mit spezifischen Risiken behafteten medikamentösen oder operativen Therapiealternativen wertvolle Bausteine der geriatrischen Inkontinenzbehandlung und sollten in angepasster Form flankierend oder alleinig bei der Therapie geriatrischer Patienten Anwendung finden.
Der „verzögerte Beginn“ einer
Posttraumatischen Belastungsstörung (PTBS) – ein diagnostisches
und gutachterliches Problem mit Bezug zur politischen Inhaftierung in der
DDR
Authors: Frommberger Ulrich , Frommberger Helena , Maercker Andreas
Published: August 2019

Häufiger als vielfach angenommen tritt – nach Berechnungen von 2
Metaanalysen – im Mittel bei ca. 25% der PTBS-Fälle das
Vollbild der Posttraumatischen Belastungsstörung (PTBS) erst nach mehr
als 6 Monaten auf. Die Prävalenzzahlen variieren stark je nach
untersuchter Population. Im militärischen Bereich tritt eine PTBS mit
verzögertem Beginn deutlich häufiger auf als im zivilen (38,2
vs. 15,3%). Für das Spektrum an Prävalenzzahlen werden
Unterschiede in der Definition, der Methodik, den Untersuchungskollektiven wie
auch den Traumaformen selbst verantwortlich gemacht. Je länger die
Beobachtungszeit, um so eher die Erfassung von verzögertem Beginn einer
PTBS. Für die Entstehung und Aufrechterhaltung wurden einige
Einflußfaktoren identifiziert. In der Begutachtung wird bei
verzögertem Beginn die Forderung nach
„Brückensymptomen“ gestellt. Diese sind zwar
häufig, jedoch nicht zwingend erforderlich. Am Beispiel von politischer
Inhaftierung in der DDR werden Verlaufsformen der PTBS wie auch des Subtyps des
„verzögerten Beginns“ dargestellt.
Usefulness of “Nelaton Attachment” for endoscopic submucosal dissection of colorectal neoplasms
Authors: Yoshimoto Taiji , Takihara Hiroshi , Yoshihara Tomoatsu , Inoue Taro , Ishibashi Kohei , Uraoka Masanao , Nakamura Akihiro , Hiramatsu Shinsuke , Baba Shinichi , Abe Shun , Matsuura Ko , Hoshikawa Masato , Taketani Rika , Tanaka Hironori , Motozato Kenichiro , Tanigawa Yuji , Nakao Eisuke , Yokomura Akitaka , Kono Michihito , Kagari Kenji , Furuta Akito , Sunada Asuka , Maejima Kenji , Tsuyuguchi Eri , Yamasaki Yasuo , Shishimoto Takahiro
Published: August 2019

Background and study aims Although colorectal endoscopic submucosal dissection (ESD) has enabled high en bloc resection rates regardless of tumor size, colorectal ESD is still a challenging procedure. We developed a novel device called the Nelaton Attachment, which allows endoscopists to manipulate the ESD knives using two fingers of their left hand while holding the endoscope with their right hand. We retrospectively investigated the efficacy and safety of the Nelaton Attachment for colorectal ESD. We compared efficacy and safety between Nelaton Attachment and non-Nelaton Attachment groups, and also conducted an ex vivo experiment to evaluate the effect of the Nelaton Attachment.

Patients and methods We retrospectively reviewed 36 consecutive patients with 37 colorectal tumors who had undergone ESD at Kishiwada Tokushukai Hospital and Naritatomisato Tokushukai Hospital between April 2016 and September 2018. The Nelaton Attachment was used for 22 of the 37 colorectal ESDs. In the ex vivo experiment, endoscopists inserted and withdrew an ESD knife 2 cm using two fingers of their left hand with and without the Nelaton Attachment.

Results Median procedure time was significantly shorter in the Nelaton Attachment group (38 min [range 6 – 195 min]) compared to the non-Nelaton Attachment group (75 min [range 17 – 198 min]; P = 0.030). Median time to complete the ex vivo experiment five times was significantly faster with the Nelaton Attachment than without the Nelaton Attachment (P = 0.001).

Conclusions Use of the Nelaton Attachment for colorectal ESD is feasible and safe, and may facilitate colorectal ESD procedures.
High proficiency of colonic endoscopic submucosal dissection in Europe thanks to countertraction strategy using a double clip and rubber band
Authors: Jacques Jérémie , Charissoux Aurélie , Bordillon Pierre , Legros Romain , Rivory Jérôme , Hervieu Valérie , Albouys Jérémie , Guyot Anne , Ponchon Thierry , Sautereau Denis , Kerever Sebastien , Pioche Mathieu
Published: August 2019

Background and study aims ESD in the colon is more challenging technically than in other locations. Here, we report the first comparative case series of colon ESD using a systematic countertraction strategy using two clips and a rubber band.

Patients and methods Retrospective comparative study of classic versus countertraction colon ESD performed in colon ESD cases collected prospectively at Lyon Edouard Herriot Hospital and Limoges University Hospital from January 2016 until December 2017.

Results The study included 192 cases (control = 76, countertraction = 116). Countertraction using the double clip and rubber band technique versus the control group resulted in a significant decrease in the procedure time (94.7 vs. 117 min; P = 0.004) and significant increases in procedure speed (28.2 vs. 16.7 mm2/min; P < 0.0001), en bloc resection rate (95.7 % vs. 76.3 %, P < 0.0001), and R0 resection rate (78.5 % vs. 64.5 %, P = 0.04).

At an individual operator point of view, results varied between operators but the double clip countertraction strategy significantly increased the en bloc resection rate, R0 resection rate, and speed of dissection for each of the 4 operators.

Conclusion Systematic countertraction using a double clip and rubber band facilitates colon ESD. This strategy should become the standard for colon ESD.
Primitive neuroectodermal tumor of the esophagus with metastasis in the pineal gland
Authors: Blas Jhon Leonardo , Sánchez-Fayos Paloma , Martín Relloso Maria Jesus , Calero Barón Daniel , Porres Cubero Juan Carlos
Published: August 2019

Primitive neuroectodermal tumors (PNET) are very rare tumors that belong to a family of malignant neoplasms of tiny round cells which are derived from the neural crest. This report discusses a rare case of an adult woman with esophageal PNET, confirmed by immunohistochemistry, that presented with metastasis to the pineal gland. To our knowledge, this is the first case report of a PNET with these features. Despite surgery and chemotherapeutic treatment, our case has shown disease progression.
Is Precise Targeting of the Recipient Artery in a Superficial Temporal Artery–Middle Cerebral Artery Anastomosis Crucial?
Authors: Katano Hiroyuki , Yamada Hiroshi , Nishikawa Yusuke , Yamada Kazuo , Miyachi Shigenori , Mase Mitsuhito
Published: August 2019

Objective To investigate the difference in treatment outcomes according to the method used to select the recipient artery in superficial temporal artery–middle cerebral artery (STA-MCA) anastomoses.

Methods We retrospectively analyzed the cases of 35 patients who underwent an STA-MCA anastomosis for internal carotid artery/MCA occlusion or stenosis. Patients were divided into two groups based on whether the recipient artery was precisely targeted by single-photon emission computed tomography (SPECT group) or less precisely targeted by visual assessment (Visual group). Then the bypass results in both groups were evaluated postoperatively based on changes in the regional cerebral blood flow (rCBF) and clinical outcomes.

Results The delineated recipient artery in magnetic resonance angiography (MRA) matched the intraoperatively selected artery in 87.6% of the SPECT group cases and 83.3% of the Visual group cases. The SPECT group's digital subtraction angiography (DSA) findings coincided with the intraoperative selection in 76.9% of cases, and the MRA findings corresponded with the DSA findings in 92.3%. The postoperative areas with increased rCBF matched the perfused areas of intraoperatively selected arteries in 80.0% of the SPECT group cases and 77.8% of the Visual group cases. Postoperatively increased rCBF areas matching totally or partially with preoperative low-perfusion areas were observed in all cases.

Conclusions The present results revealed no significant differences in the change in rCBF in the low-perfusion area between the patients whose recipient arteries were selected by SPECT or visual assessment.
Fixação intramedular flexível para fraturas diafisárias dos ossos do antebraço em crianças
Authors: Acharya Balakrishnan M. , Devkota Pramod , Thakur Abhishek K. , Gyawali Bidur
Published: August 2019

Objetivos A maioria das fraturas dos ossos do antebraço em crianças é tratada com sucesso de forma conservadora com redução fechada e imobilização gessada. No entanto, alguns pacientes podem necessitar de manipulação adicional da fratura ou intervenção cirúrgica devido a angulações residuais. O presente estudo avalia o resultado clinico e radiológico do tratamento de fraturas com desvio do antebraço em crianças fixadas com haste elástica intramedular de titânio.

Métodos Um total de 31 pacientes com idades entre 7 e 15 anos com fraturas com desvio do antebraço foram submetidos a haste elástica de titânio flexível. Os pacientes foram acompanhados por um período médio de 8,51 meses (variação: 6–12 meses) e avaliados quanto aos resultados funcionais pelos critérios de Price e radiológicos.

Resultados Dos 31 pacientes, 21 foram submetidos a redução fechada e 10 necessitaram de abertura mínima do local da fratura durante a redução. Um total de 29 pacientes tiveram excelentes resultados com arco de movimento normal, e 2 pacientes apresentaram bons resultados. Em todos os pacientes, a consolidação ocorreu em um tempo médio de 7,9 semanas. Cinco pacientes tiveram complicações menores, como irritação da pele sobre a haste proeminente (n = 2), infecção superficial do local de inserção no rádio (n = 2) e recuo da haste ulnar (n = 1), que exigiu remoção precoce.

Conclusão A haste flexível é um método eficiente para tratamento da fratura do antebraço em crianças, permitindo mobilização precoce e retorno às atividades normais dos pacientes, com baixas e tratáveis complicações.
Implementation of Transforaminal Endoscopic Lumbar Sequestrectomy in a German University Hospital Setting: A Long and Rocky Road
Authors: Bender Michael , Gramsch Carolin , Herrmann Lukas , Kim Seong Woong , Uhl Eberhard , Schöller Karsten
Published: August 2019

Objective Microsurgical diskectomy/sequestrectomy is the standard procedure for the surgical treatment of lumbar disk herniations. The transforaminal endoscopic sequestrectomy technique is a minimally invasive alternative with potential advantages such as minimal blood loss and tissue damage, as well as early mobilization of the patient. We report the implementation of this technique in a German university hospital setting.

Methods One single surgeon performed transforaminal endoscopic sequestrectomy from February 2013 to July 2016 for lumbar disk herniation in 44 patients. Demographic as well as perioperative, clinical, and radiologic data were analyzed from electronic records. Furthermore, we investigated complications, intraoperative change of the procedure to microsurgery, and reoperations. The postoperative course was analyzed using the Macnab criteria, supplemented by a questionnaire for follow-up. Pre- and postoperative magnetic resonance imaging volumetric analyses were performed to assess the radiologic efficacy of the technique.

Results Our study population had a median age of 52 years. The median follow-up was 15 months, and the median length of hospital stay was 4 days. Median duration of surgery was 100 minutes with a median blood loss of 50 mL. Surgery was most commonly performed at the L4–L5 level (63%) and in caudally migrated disk herniations (44%). In six patients, surgery was performed for recurrent disk herniations. The procedure had to be changed to conventional microsurgery in four patients. We observed no major complications. Minor complications occurred in six patients, and in four patients a reoperation was performed. Furthermore, a significantly lower Oswestry Disability Index score (p = 0.03), a lower Short Form 8 Health Survey (SF-8) score (p = 0.001), a lower visual analog scale (VAS) lower back pain score (p = 0.03) and VAS leg pain score (p = 0.0008) at the 12-month follow-up were observed in comparison with the preoperative examination. In MRI volumetry, we detected a median postoperative volume reduction of the disk herniation of 57.1% (p = 0.02).

Conclusions The transforaminal endoscopic sequestrectomy can be safely implemented in a university hospital setting in selected patients with primary and recurrent lumbar disk herniations, and it leads to good clinical and radiologic results. However, learning curve, caseload, and residents' microsurgical training requirements clearly affect the implementation process.
Maxillofacial Injuries Related to Road Traffic Accidents: A Five Year Multi Center Analysis
Authors: Gurung Utsav Singh , Singh Gaurav , Mishra Madan , Mondal Shubhamoy , Gaur Amit
Published: August 2019

The purpose of this study was to assess the epidemiological data on maxillofacial injuries related to road traffic accidents from two multispecialty medical centers in India, and then evaluate their incidence and pattern. Data were extracted from the medical records of all road traffic accident victims with maxillofacial injuries who reported to the centers between January 2013 and December 2017. Descriptive statistics and chi-square test were used for statistical analysis; significance was set at p < 0.05. Out of 1,110 patients, highest incidence of injuries was observed in the males of age group 20 to 29 years with mean age of 25.95 years (standard deviation, 9.35 years). Head injury, laceration, and tooth luxation were the most common forms of associated injuries. The use of protective helmets and seatbelts was extremely low which was associated to higher risk of facial bone fractures. Violation of traffic rules was the most common etiology behind these accidents. These findings were statistically significant ( p < 0.05). The ever increasing incidence of maxillofacial injuries related to road traffic accidents suggests the need to deal with them promptly and wisely. Keeping an update on the changing pattern of these injuries by continuous recording and periodic evaluation of epidemiological data is helpful in the primary prevention of trauma by evolving a better trauma care program and effective treatment protocol focused on the target groups. The updated data can guide treating physicians in anticipating and diagnosing maxillofacial injuries.
Cardiac Health Awareness Among Women Presenting for Routine Health Checkup at Tertiary Care Center: Time Trends Over 15 Years
Authors: Chhabra Shibba Takkar , Kaur Gurleen , Kapoor Samir , Nagi Gagandeep , Kajal Devanshi , Bansal Mamta , Bansal Namita , Kaur Baljeet , Kaur Jaswinder , Tandon Rohit , Singh Gurbhej , Singh Bhupinder , Goyal Abhishek , Aslam Naved , Mohan Bishav , Wander Gurpreet S. ,   Gurinder
Published: August 2019

Background Women have been thought to be protected against the perils of cardiovascular disease (CVD) till late in their lives. But the literature suggests quite the opposite with CVD being a major cause of death even in young women. In contrast, the lack of awareness among women is disheartening and needs to be addressed radically.

Methods The study was designed and conducted as retrospective cohort at a tertiary care center. Data was collected from patients presenting for routine cardiac health checkup over the past 15 years. The parameters observed included age at presenting, symptoms and/or signs, plus area of residence or domicile.

Results A total of 32,831 patients presented for routine cardiac health checkup, of which 9,211 (28.1%) patients were women and 23,620 (71.9%) were men. On 5 yearly cumulative assessment, the mean attendance of women was 28.1 ± 2.5% as compared with 71.9 ± 2.6% men. Trend observed over the past 15 years revealed little change in the number of women versus men presenting for cardiac health checkup annually. Statistical significance was seen at p < 0.01. Among the women presenting for the checkup, it was observed that most women were in the postmenopausal age group (42.8%), followed by perimenopausal age group (34.6%), and least in premenopausal age group (22.5%) during the timeline of the study. A similar trend was observed in the male attendance; the input of males being higher at all instances. Noteworthy were trends of urban women (69.6%) presenting for health checkup more often as compared with 30.4% visiting from rural residence.

Conclusions Coronary artery disease (CAD) is not uncommon in female gender. It is accompanied by varying symptom presentation with high mortality. It is seen that cardiac health awareness is significantly lacking among women as compared with men. There are almost static trends observed over the past 15 years, especially in premenopausal age group and rural domicile. Corrective actions inclining toward campaigns and communication to distribute information on cardiac disease prevention and treatment modalities among women are needed to curb CAD. This may promote early detection of CAD leading to early interventions to promote a healthy heart among women. Recommendations and necessary actions steps for a woman oriented cardiac program are the need of the hour.
Correction: Palgrave Communications, volume 5
Authors:   Palgrave Communications
Published: August 2019

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Adaptive frequency control with variable speed wind turbines using data-driven method
Authors: Verij Kazemi Mohammad , Gholamian Seid Asghar , Sadati Jalil
Published: August 2019

The increasing penetration of variable speed wind turbines which use the traditional controllers reduces the inertia of power systems. Consequently, the maintenance of the frequency stability of power systems would be an important challenge. Currently, droop and inertial control methods have been used in variable speed wind turbines to control the frequency of the power network. Adjusting the gains on the droop and inertia control loops is very influential on the performance of wind turbines. However, due to the variable wind speed and power system conditions, the adjustment of the control coefficients which produces the best response in all situations seems to be impossible. In this paper, a new method for the adaptive adjustment of droop and inertia control loop gains in the doubly fed induction generator is presented. In order to eliminate the defects and problems of the power system and wind turbine modeling, it is also proposed to use the data-driven method, which only operates based on the input and output of the system. The second derivative of the error can be used to provide the adaptive adjustment of the droop and inertia control loop gains. This is done to enable faster control and to prevent frequency drooping. In the proposed control method, through implementing the K-vector nearest neighborhood, the output of the next moment is estimated. Then, the coefficients of the frequency control loops are adjusted adaptively, using the Hessian matrix. Simulation results demonstrated the proper performance of a data-driven based adaptive approach to increase the frequency nadir and to decrease the frequency variations of the power system in a steady state and a transient state.
Clebsch-Lagrange variational principle and geometric constraint analysis of relativistic field theories
Authors: Diez Tobias , Rudolph Gerd
Published: August 2019

Inspired by the Clebsch optimal control problem, we introduce a new variational principle that is suitable for capturing the geometry of relativistic field theories with constraints related to a gauge symmetry. Its special feature is that the Lagrange multipliers couple to the configuration variables via the symmetry group action. The resulting constraints are formulated as a condition on the momentum map of the gauge group action on the phase space of the system. We discuss the Hamiltonian picture and the reduction in the gauge symmetry by stages in this geometric setting. We show that the Yang–Mills–Higgs action and the Einstein–Hilbert action fit into this new framework after a (1 + 3)-splitting. Moreover, we recover the Gauß constraint of Yang–Mills–Higgs theory and the diffeomorphism constraint of general relativity as momentum map constraints.
Global existence of discretely self-similar solutions to the generalized MHD system in Besov space
Authors: Zhang Jingjing , Zhang Ting
Published: August 2019

In this article, we consider the existence of discretely self-similar solutions and self-similar solutions to the 3D generalized magnetohydrodynamics (MHD) system with fractional dissipative terms (−Δ)αv and (−Δ)αH, 78<α<54. Using the Brouwer fixed-point theorem and Littlewood analysis method, we prove the global existence of discretely self-similar solutions and self-similar solutions to the 3D generalized MHD system when the initial data are in the critical space Lw32α−1 or the critical Besov space Ḃp,∞1−2α+3p, where 32α−1<p<65−4α, p<3α−1 when 76≤α<54.
Rank-one basis made from matrix-product states for a low-rank approximation of molecular aggregates
Authors: Nishio Soichiro , Kurashige Yuki
Published: August 2019

An efficient low-rank approximation to complete active space (CAS) wavefunctions for molecular aggregates is presented. Molecular aggregates usually involve two different characteristic entanglement structures: strong intramolecular entanglement and weak intermolecular entanglement. In the method, low-lying electronic states of molecular aggregates are efficiently expanded by a small number of rank-one basis states that are direct products of monomolecular wavefunctions, each of which is written as a highly entangled state such as the matrix product state (MPS). The complexities raised by strong intramolecular entanglement are therefore encapsulated by the MPS and eliminated from the degree of freedom of the effective Hamiltonian of molecular aggregates. It is demonstrated that the excitation energies of low-lying excited states of a pair of bacteriochlorophyll units with CAS(52e, 50o) are accurately reproduced by only five rank-one basis states. Because the rank-one basis states naturally have diabatic character and reproduce the low-lying spectrum of the CAS space, off-diagonal elements of the Hamiltonian are expected to give accurate diabatic couplings. It is also demonstrated that the energy splitting and the diabatic couplings in anthracene dimer systems are improved by augmenting with additional rank-one basis states.
A first principles study of a spin-polarized two-dimensional polar metal at the SrVO3/PbTiO3 heterostructure interface
Authors: Shen Menglan , Weng Yakui , Yi Yingwei , Geng Qingfeng , Yan Wei , Wang Haiyun , Yang Jianping , Li Xing’ao
Published: August 2019

The electronic structure, magnetic properties, and atomic structure of SrVO3/PbTiO3 superlattices along different crystallographic orientations are investigated using density functional theory. It is revealed that Ti ions in the PbTiO3 layers exhibit a weak ferromagnetic order. Such ferromagnetism in the PbTiO3 layers near the interface is related to charge transfer from V to Ti and the ferroelectric polarization of PbTiO3. The electronic structure of the superlattices indicates that spin-polarized two-dimensional polar metals are obtained for all orientations. In addition, different superlattice orientations correspond to different bandwidths of 3d orbitals of SrVO3 due to the dimensional confinement effect. The present work suggests a possible scenario by which two-dimensional polar metals and the coupling between the structural, electronic, and magnetic degrees of freedom in oxide superlattices can be extensively explored.
Current-feedback-stabilized laser system for quantum simulation experiments using Yb clock transition at 578 nm
Authors: Takata Y. , Nakajima S. , Kobayashi J. , Ono K. , Amano Y. , Takahashi Y.
Published: August 2019

We developed a laser system for the spectroscopy of the clock transition in ytterbium (Yb) atoms at 578 nm based on an interference-filter stabilized external-cavity diode laser (IFDL) emitting at 1156 nm. Owing to the improved frequency-to-current response of the laser-diode chip and the less sensitivity of the IFDL to mechanical perturbations, we succeeded in stabilizing the frequency to a high-finesse ultra-low-expansion glass cavity with a simple current feedback system. Using this laser system, we performed high-resolution clock spectroscopy of Yb and found that the linewidth of the stabilized laser was less than 320 Hz.
As-related stability of the band gap temperature dependence in N-rich GaNAs
Authors: Zdanowicz E. , Ciechanowicz P. , Opolczynska K. , Majchrzak D. , Rousset J.-G. , Piskorska-Hommel E. , Grodzicki M. , Komorowska K. , Serafinczuk J. , Hommel D. , Kudrawiec R.
Published: August 2019

GaNAs layers with a low As concentration (As ≤ 0.6%) have been grown by molecular beam epitaxy and studied by structural and optical methods. It has been observed that the incorporation of a small amount of As atoms into the GaN host leads to a significant reduction of the bandgap due to the formation of an As-related band above the valence band of the GaN host. The position of this band does not change with temperature, and therefore, a reduced temperature dependence of the bandgap is observed for As-diluted GaN compared to the pure GaN host, which is ∼40 meV vs ∼70 meV in the 10–295 K temperature range. The observed effect is explained within the band anticrossing model. It is expected that the reduced temperature dependence of the bandgap in As-diluted GaN can be utilized in lasers with improved thermal stability.
Competing factors in grain boundary loop shrinkage: Two-dimensional hard sphere colloidal crystals
Authors: Guo Ziwei , Kindt James T.
Published: August 2019

A grain boundary (GB) loop in a two-dimensional solid is the boundary of a domain or grain whose lattice orientation is mismatched with its uniform surroundings. Understanding the factors that influence the rate at which the interior of a GB loop relaxes to the orientation of its surroundings is an important step toward control and predictability of grain coarsening in general. Recent computational and experimental studies looking at the rate of GB loop shrinkage in two-dimensional colloidal hard sphere solids have uncovered contradictory trends: in experiments, GB loops with low misorientation angles shrank the fastest, while in simulations, they persisted the longest. In this study, the computational system’s behavior is brought into qualitative agreement with the experimental results through increasing the lateral packing pressure, decreasing the domain size, and mimicking the experimental protocol used to form the GB loop. Small GB loops with the same misorientation, but displaying either a hexagonal or starlike grain shape depending on the orientation of their six dislocations, are shown to differ in their rates of shrinkage by two orders of magnitude. The evidence suggests that both the barrier to generating new dislocations as well as the pattern of dislocations formed by different GB loop preparation methods will determine which trend is observed.
Multipole-based distance-dependent screening of Coulomb integrals
Authors: Irmler Andreas , Pauly Fabian
Published: August 2019

We derive a new estimate for two-electron repulsion integrals (ERIs), when evaluated within a local atomic basis set. It is based on the multipole expansion and provides a rigorous upper bound of an ERI for well-separated charge distributions. The scheme is generally applicable in any formalism that uses ERIs. We employ it here to screen for potentially negligible contributions in the calculation of the Fock exchange matrix. Using Gaussian basis functions, we show that the estimate allows us to accelerate the construction of the exchange matrix by up to a factor of two without introducing further approximations.
Influences of sintering atmosphere on the magnetic and electrical properties of barium hexaferrites
Authors: Zhang Xiaozhi , Zhang Yao , Yue Zhenxing , Zhang Jincang
Published: August 2019

BaFe12O19 (BaM) hexaferrite has drawn increasing attention due to the high magneto-crystalline anisotropy and chemical stability, being a promising candidate in the field of magnetic microwave devices and magnetoelectric multiferroics. In this work, we studied the differences in microstructure and physical properties of BaM ceramics sintered in different atmospheres of nitrogen and air. It is found that N2 atmosphere does not significantly affect the morphology and magnetic properties of BaM, but dramatically reduces the resistivity from ∼ 1010 to ∼ 105 Ω·cm. By virtue of X-ray photoelectron and impedance analysis, the reduced resistance and increased permittivity value of the N2-sintered BaM were ascribed to the electron hopping mechanism caused by the formation of Fe2+ from Fe3+ ions.
Inverse design of charged colloidal particle interactions for self assembly into specified crystal structures
Authors: Kumar Rajneesh , Coli Gabriele M. , Dijkstra Marjolein , Sastry Srikanth
Published: August 2019

We study the inverse problem of tuning interaction parameters between charged colloidal particles interacting with a hard-core repulsive Yukawa potential, so that they assemble into specified crystal structures. Here, we target the body-centered-cubic (bcc) structure which is only stable in a small region in the phase diagram of charged colloids and is, therefore, challenging to find. In order to achieve this goal, we use the statistical fluctuations in the bond orientational order parameters to tune the interaction parameters for the bcc structure, while initializing the system in the fluid phase, using the Statistical Physics-inspired Inverse Design algorithm. We also find that this optimization algorithm correctly senses the fluid-solid phase boundaries for charged colloids. Finally, we repeat the procedure employing the covariance matrix adaptation-evolution strategy, a cutting edge optimization technique, and compare the relative efficacy of the two methods.
Coherent structures in tornado-like vortices
Authors: Karami M. , Hangan H. , Carassale L. , Peerhossaini H.
Published: August 2019

The dynamics of tornadolike vortices is investigated through a set of novel physical experiments and modal analyses for a wide range of swirl ratios (0.22 ≤ S ≤ 0.96). Various physical phenomena such as wandering, vortex breakdown, or transition from one-cell to two-cell structures are observed. To investigate the coherent structure of the tornado vortices, two different decomposition methods are applied: (i) proper orthogonal decomposition (POD), also referred to as principle component analysis, and (ii) a novel dynamic proper orthogonal decomposition to provide time evolutions of the POD modes. To foster the physical interpretation of these POD modes, we also applied modal decomposition on a simulated synthetic vortex. The results show that at low swirl ratios before vortex breakdown, the flow is characterized by a single vortex which is tilted at lower heights. For intermediate swirls, before vortex touchdown, the flow is characterized by a recirculation bubble with a single spiral rotating around it. By further increasing the swirl ratio, transition from a single spiral to a double spiral (one-cell to two-cell structures) occurs. Based on these observations, a simple vortex structure of tornadolike vortex is put forward which can be used to generate a low order, large scale turbulence model for these types of flows.
High harmonic generation spectroscopy via orbital angular momentum
Authors: Troß Jan , Trallero-Herrero Carlos A
Published: August 2019

We present an experimental technique using orbital angular momentum (OAM) in a fundamental laser field to drive high harmonic generation (HHG). The mixing of beams with different OAM allows us to generate two laser foci tightly spaced which generate harmonics that interfere in the far field. Thus, this technique is an OAM based in situ HHG interferometric spectroscopic method. With this tool, we measure the phase and amplitude of the angle dependent multiorbital HHG emission in molecular nitrogen.
Low frequency cyclical potentials for fine tuning insulator-based dielectrophoretic separations
Authors: Lentz Cody J. , Hidalgo-Caballero Samuel , Lapizco-Encinas Blanca H.
Published: August 2019

In this study, we demonstrate the use of cyclical low frequency signals with insulator-based dielectrophoresis (iDEP) devices for the separation of particles of similar characteristics and an experimental method for estimating particle DEP mobilities. A custom signal designer program was created using Matlab® and COMSOL Multiphysics® for the identification of specific low frequency signals aimed at separating particle mixtures by exploiting slight differences in surface charge (particle zeta potential) or particle size. For the separation by surface charge, a mixture of two types of 10 μm particles was analyzed and effectively separated employing both a custom step signal and a sawtooth left signal. Notably, these particles had the same shape, size, and surface functionalization as well as were made from the same substrate material. For the separation by size, a sample containing 2 μm and 5 μm particles was successfully separated using a custom step signal; these particles had the same shape, surface functionalization, were made from the same substrate materials, and had only a small difference in zeta potential (10 mV). Additionally, an experimental technique was developed to estimate the dielectrophoretic mobility of each particle type; this information was then utilized by the signal designer program. The technique developed in this study is readily applicable for designing signals capable of separating micron-sized particles of similar characteristics, such as microorganisms, where slight differences in cell size and the shape of surface charge could be effectively exploited. These findings open the possibility for applications in microbial screening using iDEP devices.
Adaptable microfluidic device improves the measurement of cancer cell migration and trapping
Authors: Mandel Savannah
Published: August 2019

New system allows control over seeding cancer cells at specific locations, assuring reliable location data and enabling the use of 1D migration assays.
Interaction between herbage mass and time of herbage allocation modifies milk production, grazing behaviour and nitrogen partitioning of dairy cows
Authors: Beltrán Ignacio E. , Gregorini Pablo , Morales Alvaro , Balocchi Oscar A. , Pulido Rubén G.
Published: August 2019

The objective of the present study was to evaluate the interaction effects between herbage mass and time of herbage allocation on milk production, grazing behaviour and nitrogen partitioning in lactating dairy cows. Forty-four Holstein Friesian cows were grouped according to milk production (24.7 ± 2.8 kg), bodyweight (580.6 ± 51.7 kg), days in milk (74 ± 17.1) and body condition score (3.1 ± 0.3), and then assigned randomly to one of four treatments: (1) L-AM: access to new herbage allocation after morning milking with herbage mass of 2000 kg DM/ha, (2) L-PM: access to new herbage allocation after afternoon milking with herbage mass of 2000 kg DM/ha, (3) M-AM: access to new herbage allocation after morning milking with herbage mass of 3000 kg DM/ha, and (4) M-PM: access to new herbage allocation after afternoon milking with herbage mass of 3000 kg DM/ha. All cows received a daily low herbage allowance of 21 kg DM measured above ground level, 3.0 kg DM of grass silage and 3.5 kg DM of concentrate. Herbage intake was similar between treatments, averaging 8.3 kg DM/day (P > 0.05). Total grazing time was lower for M-PM compared with other treatments (P < 0.01). Milk production was greater for M-AM and M-PM compared with L-PM (P < 0.05). Urea in milk and plasma were greater for L-AM than L-PM and M-PM (P < 0.01). Similarly, rumen ammonia was greater for L-AM compared with M-PM and M-AM (P < 0.05). Nitrogen intake was 13.6% greater for L-AM than L-PM, and 17.5% greater for L-AM than M-PM (P < 0.05). Nitrogen use efficiency was 22.1% greater for M-PM than L-AM, and 11.8% greater for M-PM than L-PM (P < 0.01). In conclusion, the best management combination was observed when a medium herbage mass was delivered in the afternoon, maintaining a low nitrogen intake, low urinary nitrogen excretion and high milk production.
Automatically monitoring of dietary effects on rumination and activity of finishing heifers
Authors: Giaretta E. , Mordenti A. L. , Canestrari G. , Palmonari A. , Formigoni A.
Published: August 2019

Rumination and activity behaviours are important welfare indexes in beef-cattle housing. The main objective of the present study was to assess whether the automatic collars are able to reliably assess the rumination and activity patterns of beef heifers. For this purpose, individual rumination time and activity (RT and AT respectively) were continuously recorded using an automatic neck-collar system (Hr-Tag, SCR Engineers Ltd, Israel) on the three trials performed. For Experiment 1, 60 Italian crossbred heifers were randomly assigned to one of two experimental diets for 9 months: the corn–silage diet (CS), which included 50% forage on a dry-matter (DM) basis (43% corn–silage, 7% wheat straw) and the hay diet (HAY), with 57% forage on DM basis (28.5% grass hay, 28.5% alfalfa hay). Heifers consuming HAY diet showed greater (P < 0.05) RT (min/day) and AT (bits/day) than did those on CS diet. Rumination time per kilogram of dry matter and per kilogram of amylase- and sodium sulfite-treated neutral detergent fibre corrected for ash residue (aNDFom) intake were similar in the two experimental groups, while RT per kilogram of physical effective NDF (peNDF) intake was greater (P < 0.05) in the CS group than in the HAY one. Daily rumination and activity patterns (min/2 h and bits/2 h respectively) were significantly different between CS and HAY groups. In the second experiment, 32 beef heifers were randomly allocated in two homogeneous pens, each containing eight animals, and two non-homogeneous ones, in which animals were added at different periods. The AT of non-homogeneous pens was significantly higher than that of the homogeneous ones, suggesting a distress condition for values higher than 309 bits/day AT. In the third experiment, RT and AT of three animals with respiratory disease were collected using the automatic collar system and compared with AT and RT of the healthy animals. Sick animals presented a significantly lower RT and higher AT than did the healthy ones. The cut-off to distinguish sick from healthy heifers was set to 537 bits/day AT and 381 min/day RT. In conclusion, the present study demonstrated that automatic collars can reliably monitor different rumination and activity behaviours of beef animals in various management conditions and different health statuses.
Creating a low enteric methane emission ruminant: what is the evidence of success to the present and prospects for developing economies?
Authors: Goopy J. P.
Published: August 2019

Enteric methane emissions from livestock constitute a greater part of anthropogenic greenhouse gases (GHGs) in Africa, than in more industrialised economies, providing a strong incentive for the development of low methane phenotype ruminants. Although dietary and husbandry options already exist for lowering methane production, means of changing ‘methane status’ of animals enduringly has a strong appeal. This paper is a critical review the empirical success to date of attempts to alter this status. Introduction of reductive acetogens, defaunation, anti-methanogen vaccines, early life programming and genetic selection at both the rumen and animal level are considered in turn. It is concluded that to date, there is little in vivo evidence to support the practical success of any of these strategies, save selective breeding, and this at a high cost with unknown efficacy. Finally, it is suggested that for developing economies management and nutritional strategies to reduce emissions will have the greatest and most immediate impact, at the lowest cost.