bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the orientation of narrow-line Seyfert I
Authors: Sbarrato Tullia , Dotti Massimo , Ghirlanda Giancarlo , Tavecchio Fabrizio
Published: May 2018

We study a sample of narrow-line Seyfert 1 galaxies (NLS1) in their optical and radio features to understand the differences between their radio silent, radio-loud, and radio-quiet subclasses. We first show that the different redshift and mass distributions of radio-loud and radio-quiet NLS1s could be ascribed to observational biases. We then present a geometrical model according to which most of the different observational features of radio-loud and radio-quiet NLS1s are ascribed to the orientation of an intrinsically structured jet. We estimate the fraction of intrinsically jetted sources among NLS1s that justifies the observed radio-detected population. Noticeably, under the assumptions of the geometrical model, we derive a fraction of jetted sources significantly larger than in standard AGN.
Non-linear seismic scaling relations
Authors: Kallinger T. , Beck P. G. , Stello D. , Garcia R. A.
Published: May 2018

Context. In recent years the global seismic scaling relations for the frequency of maximum power, νmax ∝ g / √Teff, and for the large frequency separation, Δν ∝ √ρ¯, have drawn attention in various fields of astrophysics. This is because these relations can be used to estimate parameters, such as the mass and radius of stars that show solar-like oscillations. With the exquisite photometry of Kepler, the uncertainties in the seismic observables are small enough to estimate masses and radii with a precision of only a few per cent. Even though this seems to work quite well for main-sequence stars, there is empirical evidence, mainly from studies of eclipsing binary systems, that the seismic scaling relations systematically overestimate the mass and radius of red giants by about 15% and 5%, respectively. Various model-based corrections of the Δν-scaling reduce the problem but do not solve it.

Aims. Our goal is to define revised seismic scaling relations that account for the known systematic mass and radius discrepancies in a completely model-independent way.

Methods. We use probabilistic methods to analyse the seismic data and to derive non-linear scaling relations based on a sample of six red giant branch (RGB) stars that are members of eclipsing binary systems and about 60 red giants on the RGB as well as in the core-helium burning red clump (RC) in the two open clusters NGC 6791 and NGC 6819.

Results. We re-examine the global oscillation parameters of the giants in the binary systems in order to determine their seismic fundamental parameters and we find them to agree with the dynamic parameters from the literature if we adopt non-linear scalings. We note that a curvature and glitch corrected Δνcor should be preferred over a local or average value of Δν. We then compare the observed seismic parameters of the cluster giants to those scaled from independent measurements and find the same non-linear behaviour as for the eclipsing binaries. Our final proposed scaling relations are based on both samples and cover a broad range of evolutionary stages from RGB to RC stars: g / √Teff = (νmax / νmax,⊙)1.0075±0.0021 and √ρ¯ = (Δνcor / Δνcor,⊙)[η − (0.0085 ± 0.0025) log2(Δνcor / Δνcor,⊙)]−1, where g, Teff, and ρ¯ are in solar units, νmax,⊙ = 3140 ± 5 μHz and Δνcor,⊙ = 135.08 ± 0.02 μHz, and η is equal to one in the case of RGB stars and 1.04 ± 0.01 for RC stars.

Conclusions. A direct consequence of these new scaling relations is that the average mass of stars on the ascending giant branch reduces to 1.10 ± 0.03 M⊙ in NGC 6791 and 1.45 ± 0.06 M⊙ in NGC 6819, allowing us to revise the clusters’ distance modulus to 13.11 ± 0.03 and 11.91 ± 0.03 mag, respectively. We also find strong evidence that both clusters are significantly older than concluded from previous seismic investigations.
Kinematics of outer halo globular clusters: M 75 and NGC 6426
Authors: Koch Andreas , Hanke Michael , Kacharov Nikolay
Published: May 2018

Globular clusters (GCs) and their dynamic interactions with the Galactic components provide an important insight into the structure and formation of the early Milky Way. We present a kinematic study of two outer halo GCs based on a combination of VLT/FORS2, VLT/FLAMES, and Magellan/MIKE low- and high-resolution spectroscopy of 32 and 27 member stars, respectively. Although both clusters are located at Galactocentric distances of 15 kpc, they have otherwise very different properties. M 75 is a luminous and metal-rich system at [Fe/H] = −1.2 dex, which is a value that we confirm from the calcium triplet region. This GC shows mild evidence for rotation with an amplitude of Arot ~ 5 km s−1. One of the most metal-poor GCs in the Milky Way (at [Fe II/H] = −2.3 dex), NGC 6426 exhibits marginal evidence of internal rotation at the 2 km s−1 level. Both objects have velocity dispersions that are consistent with their luminosity. Although limited by small-number statistics, the resulting limits on their Arot/σ0 ratios suggest that M 75 is a slow rotator driven by internal dynamics rather than being affected by the weak Galactic tides at its large distances. In this work, M 75 (Arot/σ0 = 0.31) is fully consistent with the properties of other, younger halo clusters. At Arot/σ0 = 0.8 ± 0.4, NGC 6426 appears to have a remarkably ordered internal motion for its low metallicity, but the large uncertainty does not allow for an unambiguous categorization as a fast rotator. An accretion origin of M 75 cannot be excluded, based on the eccentric orbit, which we derived from the recent data release 2 of Gaia, and considering its younger age.
Mehr Sinnhaftigkeit im Leben
Authors: Berlinghof Lena
Published: May 2018

Um jungen Erwachsenen wieder mehr Sinn im Leben zu geben und ihre persönliche Entwicklung zu fördern, wurde auf einer psychiatrischen Station die offene Gesprächsgruppe „SINN macht Sinn“ eingerichtet. Sie vermittelt den Patienten praktisches Wissen, um Alltagsprobleme besser bewältigen zu können. Wir stellen Ihnen das Konzept und die einzelnen Module vor.
Das Team braucht Hilfe
Authors: Heinrich Benjamin
Published: May 2018

Im sechsten Teil unserer Serie geht es um eine suchtkranke Patientin, deren Aggressionsausbrüche durch das rücksichtlose und ungerechte Verhalten eines
Pflegenden gefördert werden, was sich negativ auf die Teamintegrität auswirkt. Lesen Sie, wie das Pflegeteam es schafft, mithilfe der systemischen
Fallbesprechung neue Perspektiven zu entwickeln. Auch hier möchten wir Sie wieder einladen, sich selbst in die verschiedenen Rollen hineinzuversetzen. Fallen
Ihnen weitere Lösungswege ein? Dann schreiben Sie uns an psych.pflegeheute@thieme.de.
Licht und Dunkel
Authors: Lang Friederike
Published: May 2018

Die folgenden Gedanken zum Thema psychische Erkrankung basieren auf meinen persönlichen Erfahrungen und entsprechender Literatur. Als ich im Januar 2017
angefangen habe zu schreiben, war ich gerade in der tiefsten Krankheitsphase. Ich habe beabsichtigt, mich mit dem Schreiben abzulenken und meine Gedanken zu
ordnen. Ich wollte versuchen, mich selbst und die Krankheit besser zu verstehen. Wenn auch Sie, liebe Leserinnen und Leser, dadurch ein wenig mehr Einblick
erhalten und mehr Verständnis für Menschen mit psychischen Erkrankungen entwickeln, dann habe ich mit dem Schreiben mehr erreicht, als ich je gehofft habe.
Angst vor Stigmatisierung
Authors: Mathis Daniel
Published: May 2018

Viele psychisch Erkrankte scheuen sich davor, zur stationären Erstaufnahme in eine Fachklinik zu gehen, weil sie Sorge haben, im Sozial- oder Berufsleben stigmatisiert zu werden. Welche Ängste dahinter stecken und wie sie abgebaut werden könnten, hat unser Autor im Rahmen einer Umfrage herausgefunden.
Aktueller Stellenwert der Antidots unter
NOAK-Therapie
Authors: Gonska Bernd-Dieter
Published: May 2018

Die oralen Nicht-Vitamin-K-Antagonisten (NOAK) sind ein fester Bestandteil der
Therapie des nicht-valvulären Vorhofflimmerns, der Beinvenenthrombose und der
Lungenembolie. Den klar bestehenden Vorteilen steht als Nachteil das Fehlen
spezifischer Antidot gegenüber. Zurzeit ist nur für Dabigatran ein spezifisches
Antidot erhältlich. Idarucizumab ist nach i. v.-Gabe schnell wirksam. Für die
Faktor-Xa-Antagonisten sind spezifische Antidots noch nicht verfügbar.
A Metal-Free Synthesis of 3-Phenoxyimidazo Heterocycles by Catalytic Oxidative Cyclization of 2-Amino-azaarenes with Lignin Models
Authors: Zhao Li , Zhang Jian , Zhong Guofu , Chen Yizhou , Wang Shanlu , Rong Chenyan , Liu Tong , Sun Han , Wang Yuping
Published: May 2018

A metal-free catalytic oxidative cyclization of 2-aminopyridines and 2-aminobenzothiazole with lignin model 2-phenoxyacetophenones was developed, in which inexpensive iodine was used as the catalyst and tert-butyl hydroperoxide (TBHP) was the oxidant. The reaction proceeded smoothly under an air atmosphere to produce valuable 3-phenoxyimidazo[1,2-a]pyridines and 3-phenoxybenzo[d]imidazo[2,1-b]thiazoles, respectively, in moderate to good yields.
The Direct Pd-Catalyzed β-C(sp3)–H Activation of Carboxylic Acids
Authors: van Gemmeren Manuel , Uttry Alexander
Published: May 2018

The carboxylic acid moiety is one of the most versatile and abundant functional groups. However, despite of tremendous progress in the field of C–H functionalization reactions its use as a directing group for C(sp3)–H activation has remained limited. In this Synpact article we present the challenges associated with the carboxylic acid moiety as a native directing group and report on the newest developments in this field, including our recent study in which we developed a generally applicable protocol for the direct palladium catalyzed β-C(sp3)–H arylation of propionic acid and related α-branched aliphatic acids giving access to hydrocinnamic acids derivatives in a highly straightforward manner.

1 Introduction

2 Challenges in the C(sp3)–H Bond Activation of Carboxylic Acids

3 History/State of the Art

4 Studies towards a General β-C(sp3)–H Functionalization of ­Aliphatic Acids

5 Conclusion
Muscle-Tendon-Enthesis Unit
Authors: Huang Brady , Pathria Mini , Tadros Anthony
Published: May 2018

Injuries to the muscle-tendon-enthesis unit are common and a significant source of pain and loss of function. This article focuses on the important anatomical and biomechanical considerations for each component of the muscle-tendon-enthesis unit. We review normal and pathologic conditions affecting this unit, illustrating the imaging appearance of common disorders on magnetic resonance imaging and ultrasound. Knowledge of the anatomy and biomechanics of these structures is crucial for the radiologist to make accurate diagnoses and provide clinically relevant assessments.
Is Right Sleeve Lower Lobectomy Necessary? Is It Safe?
Authors: Kocaturk Celalettin Ibrahim , Saydam Ozkan , Sezen Celal Bugra , Kalafat Cem Emrah , Cansever Levent , Kutluk Ali Cevat , Akin Hasan , Metin Muzaffer
Published: May 2018

Objectives The right sleeve lower lobectomy is the least used of the bronchial sleeve operations. There are only case-based studies in the literature. In this study, we compared this technique to those used in patients who underwent a right lower bilobectomy.

Methods We retrospectively reviewed the data of patients who had been operated on due to non-small cell lung cancer (NSCLC) from January 2005 to December 2015 from a dataset that was formed prospectively. Of the 4,166 patients who underwent resections due to NSCLC, the files of those who had a right sleeve lower lobectomy (group S) and those who had a right lower bilobectomy (group B) were evaluated. The remaining 25 patients in group B and 18 patients in group S were compared in terms of demographic data, morbidity, hospitalization time, mortality, histopathology, recurrence, and total survival.

Results No significant differences in the demographic or clinical characteristics were observed between the two groups, except that group S had more female patients. Postoperative complications developed in 52% of the patients in group B and 11.1% of the patients in group S (p = 0.006). Mean hospitalization time was 9.6 ± 3.6 (range, 6–19) days in group B and 6.72 ± 1.5 (range, 4–9) days in group S (p = 0.001). All patients received complete resections. The mean patient follow-up time was 42.9 months. No significant difference was found between local and distant recurrences (p = 1, p = 0.432). Mean survival time was 89.6 months (5-year rate = 73%), which was 90.6 months (5-year rate = 75.3%) in group B and 63.1 months (5-year rate = 69.3%) in group S (p = 0.82).

Conclusion This technique allows for reduced filling of the thoracic cavity by a prolonged air leak and a reduced prevalence of complications. Additionally, the hospitalization time is shortened. It does not produce any additional mortality burden, and total survival and oncological outcomes are reliable. This technique can be used in selected patients at experienced centers.
Global Health Neurology: HIV/AIDS
Authors: Spudich Serena , Patel Payal
Published: May 2018

With the advent of combination antiretroviral therapies, the mortality rate from HIV has declined, while the prevalence of long-term HIV-related neurologic complications continues to rise. Thirty-six million individuals are living with HIV around the world, many of whom reside in resource-limited settings. The majority of studies have focused on individuals residing in the developed world, while the impact of HIV disproportionately affects people living in developing countries. This review focuses on recent domestic and international studies regarding neurologic complications related to HIV, including opportunistic infections, peripheral neuropathy, cerebrovascular disease, and HIV-associated neurocognitive disorders, in light of the growing population affected by these conditions.
Nervous System Infections and the Global Traveler
Authors: Reid Savina , Thompson Haley , Thakur Kiran
Published: May 2018

Neurological complications of infectious diseases are associated with high rates of morbidity and mortality. It is imperative that neurologists be up-to-date on current developments including typical and atypical presentations of neurological infections in travelers, diagnostic and treatment recommendations, and emerging pathogen resistance patterns to avoid fatal outcomes and long-term sequelae. This article will address concepts of emerging and reemerging infectious diseases, and will provide updates on the neurological manifestations of select emerging and reemerging infections, including Ebola virus, bacterial meningitis, enterovirus 71, Zika virus, cerebral malaria, and Japanese encephalitis. Emerging and reemerging neurotropic infectious diseases, including Zika virus, have recently been major global health threats. Factors contributing to the emergence of infectious diseases include closer contact with zoonoses, population growth in cities, globalization, environmental changes, and the rise in antibiotic resistance. Serotype replacement of bacterial meningitis, the possibility of viral persistence in the central nervous system in Ebola virus, antibiotic resistance of malaria, and the evolution of neurovirulent strains of Zika virus display some of the developing challenges that accompany various neurotropic infectious diseases. Neurologists should be aware of the factors contributing to the emergence and reemergence of neurotropic infectious diseases. As emerging and reemerging neurotropic infectious continue to be a major global health security threat, clinicians should be aware of the risks to travelers and current guidelines on prevention and management.
Multiple Sclerosis
Authors: Alroughani Raed , Yamout Bassem
Published: May 2018

Multiple sclerosis (MS) is a chronic central nervous system inflammatory disease of autoimmune etiology, mediated by activated T cells with evolving evidence of a significant contribution from B cells and cells of the innate immune system. The disease is thought to be due to a complex interaction between different genetic and environmental factors. The prevalence of MS is rising all over the world, due on one hand to earlier diagnosis and prolonged survival, and on the other to a true increase in incidence of the disease. The diagnosis of MS remains clinical despite recent advances in diagnostics and relies on demonstrating dissemination in space and time while excluding alternative diagnoses. The Mc Donald diagnostic criteria, with their recent 2017 revision, are currently widely accepted in the MS community. Although no cure is yet available, many disease-modifying therapies (DMTs) have shown different levels of efficacy in preventing relapses, accumulation of lesions on magnetic resonance imaging (MRI), and disability progression. Current treatment strategies include gradual escalation based on clinical and radiological criteria that determine treatment response, or initial induction with high efficacy DMTs especially in patients with an early aggressive course.
Postoperative Aortic Neck Dilation: Myth or Fact?
Authors: Ribner A.S. , Tassiopoulos A.K.
Published: May 2018

The abdominal aorta is the most common site of an aortic aneurysm. The visceral and most proximal infrarenal segment (aneurysm neck) are usually spared and considered more resistant to aneurysmal degeneration. However, if an abdominal aortic aneurysm (AAA) is left untreated, the natural history of the aortic neck is progressive dilatation and shortening. This may have significant implications for patients undergoing endovascular repair of AAAs (EVAR) as endograft stability and integrity of the repair are dependent on an intact proximal seal zone. Compromised seal zones, caused by progressive diameter enlargement and foreshortening of the aortic neck, may lead to distal endograft migration, type Ia endoleak, aortic sac repressurization, and, ultimately, aortic rupture.
Treatment Outcome of Reconstruction for Isolated Posterior Cruciate Injury: Subjective and Objective Evaluations
Authors: Ochiai Satoshi , Hagino Tetsuo , Senga Shinya , Yamashita Takashi , Haro Hirotaka
Published: May 2018

There is no consensus regarding the treatment method and outcome of posterior cruciate ligament (PCL) injury. We hypothesized that although the outcome of PCL reconstruction was favorable in terms of knee stability, the outcome was unsatisfactory in terms of patient-based assessments. The purpose of this study is to evaluate the treatment outcomes of knees that underwent reconstruction for PCL injury by subjective and objective assessments, and to analyze the correlation between various assessments. Twenty-three patients who underwent PCL reconstruction were studied. All reconstructions were performed arthroscopically by the single-bundle technique using a hamstring tendon autograft. Patients were evaluated clinically before operation and 24 months after operation using the 36-Item Short Form Health Survey (SF-36) which is a patient-based health assessment survey, Lysholm score, tibial translation ratio, Visual Analogue Scale (VAS) for pain, and range of motion (ROM) in the knee. The correlation of these assessment methods was analyzed. For the SF-36 survey, significant improvement was observed after operation in only 3 of 7 subscales compared with before surgery. Furthermore, the scores reached the national standard scores in only 3 subscales. While the Lysholm score and tibial translation ratio were improved significantly, no significant improvement in the VAS pain score was observed. For ROM assessment, approximately 30% of the patients had flexion restriction after operation, and the degree of restriction correlated positively with the VAS score. The present results indicated that although the outcome of PCL reconstruction was favorable in terms of knee stability and motor function, the outcome was unsatisfactory in terms of patient-based assessments. Since pain associated with flexion restriction appears to be a poor prognostic factor and there is a dissociation between subjective and objective assessments, improvement of the surgical method is necessary.
Anterior Cruciate Ligament Reconstruction with LARS Artificial Ligament—Clinical Results after a Long-Term Follow-Up
Authors: Parchi Paolo , Ciapini Gianluca , Paglialunga Carlo , Giuntoli Michele , Picece Carmine , Chiellini Fabio , Lisanti Michele , Scaglione Michelangelo
Published: May 2018

Purpose The aim of this retrospective study was to evaluate the subjective and functional outcome of anterior cruciate ligament (ACL) reconstruction with the synthetic Ligament Advanced Reinforcement System (LARS) ligament.

Methods Twenty-six patients were reviewed at an average follow-up of 11.6 years. Objective clinical evaluation was performed with stability tests. Patient-reported outcomes (Visual Analogue Scale, Knee Injury and Osteoarthritis Outcome Score, and Cincinnati Knee Rating Scale) were used to assess subjective and functional outcomes.

Results Overall satisfactory results were obtained in 22 cases (84.6%). Four patients (15.4%) showed mechanical failure of the graft. No cases of synovitis or infection were reported.

Conclusion LARS ligament can be considered a safe and suitable option for ACL reconstruction in carefully selected cases, especially elderly patients needing a rapid postoperative recovery.

Level of Evidence Level IV, retrospective case series.
The Modified Iliopubic Tract Repair—A Pain-Free Alternative
Authors: Ali Iqbal , Dikshit Vashisht , Manerikar Kshitij , Dholakia Mirat , Save Maitreyee
Published: May 2018

Background The open preperitoneal repair offers the benefits of placing the mesh in the preferred position while avoiding the disadvantages of laparoscopic repair.

Methods A total of 60 patients with bilateral inguinal hernias were randomized to undergo either the standard Lichtenstein meshplasty or the modified iliopubic tract repair in a teaching hospital. Outcomes measured were immediate postoperative pain, return to activity, and delayed neurological complications.

Results Patients who underwent the iliopubic tract repair walked out of bed faster than the Lichtenstein group (6.3 hours vs 7.4 hours, p < 0.0001) and experienced significant lower pain as charted by visual analogue scale scores (3.28 vs 2.71 on day 1, 2.16 vs 1.71 on day 2, 1.92 vs 1.08 on day 3; p < 0.05). Delayed complications like chronic inguinal pain and numbness were not seen in the iliopubic tract group. However, this difference was not statistically significant (p > 0.05).

Conclusion The iliopubic tract repair offers an excellent alternative to the Lichtenstein meshplasty, and is associated with lower postoperative pain, earlier return to work, and lower delayed neurological complications.
Fabrication of GaN single crystals at 700°C using Na-Li-Ca mixed flux system
Authors: Wu Xi , Hao Hangfei , Li Zhenrong , Fan Shiji , Xu Zhuo
Published: May 2018

GaN single crystals were grown in Na-Li-Ca flux system of which Li-Ca gradually replaces Na. X-ray powder diffraction analysis confirmed that the structure of GaN samples was wurtzite. As concentration of Li-Ca in flux increased, the shape of GaN crystals was changed from pyramidal, prism to platelets in sequence, and the color of them became transparent gradually. Among of them, the transparent prism crystals were grown first at 700°C when the concentration of Li-Ca was 31.6 mol% and 48.9 mol% in flux solution, respectively. Raman spectra implied that these crystals were stress-free and the transparent crystal grown in the high concentration of Li-Ca solution had high structural quality or low impurity concentrations.
Charge breeding of radioactive isotopes at the CARIBU facility with an electron beam ion source
Authors: Vondrasek R. C. , Dickerson C. A. , Hendricks M. , Ostroumov P. , Pardo R. , Savard G. , Scott R. , Zinkann G.
Published: May 2018

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed at Argonne National Laboratory as part of the californium rare ion breeder upgrade. For the past year, the EBIS-CB has been undergoing commissioning as part of the ATLAS accelerator complex. It has delivered both stable and radioactive beams with A/Q < 6, breeding times <30 ms, low background contamination, and charge breeding efficiencies >18% into a single charge state. The operation of this device, challenges during the commissioning phase, and future improvements will be discussed.
Wideband luminescence from bandgap-matched Mg-based Si core-shell geometry nanocomposite
Authors: Kocyigit Adem , Elhalawany Noha , Bahceci Ersin , Enders Brian , Puthalath Krithik , Abuhassan Laila , Yamani Zain , Nayfeh Munir
Published: May 2018

We use wet treatment to integrate red-luminescent Si nanoparticles with Mg-based wide-bandgap insulators Mg(OH) and MgO (5.7 and 7.3 eV respectively). In the process, Mg2+ is reduced on Si nanoparticle clusters, while suffering combustion in water, producing a spatially inhomogeneous Mg(OH)2/MgO-Si nanoparticle composite with an inner material predominantly made of Si, and a coating consisting predominantly of magnesium and oxygen (“core-shell” geometry). The nanocomposite exhibit luminescence covering nearly entire visible range. Results are consistent with formation of Mg(OH)2/MgO phase with direct 3.43-eV bandgap matching that of Si, with in-gap blue-green emitting states of charged Mg and O vacancies. Bandgap match with nanocomposite architecture affords strong enough coupling for the materials to nearly act as a single hybrid material with novel luminescence for photonic and photovoltaic applications.
How many hydrogen molecules (H2) can be stored in a clathrate hydrate cage?
Authors: Li Dapeng , Wang Shuqing , Du Qishi , Huang Ribo
Published: May 2018

Storage of hydrogen gas (H2) in clathrate hydrate at ambient conditions has many potential applications, such as clean energy, environment and ecology protection, submarine, and space rocket. In this research article, the hydrogen gas hydrate is studied by using higher level quantum chemical methods such as MP2, CCSD, and CCSD(T). The interaction energy terms in the hydrate cage and the guest molecular cluster are calculated and analyzed. Some useful conclusion points are summarized as follows: (1) The capacity and stability of the hydrogen molecular clusters in hydrate cages are determined by three energy terms: the hydrogen bond energy (ΔEH-b) of water molecules, the interaction energy (ΔEcage-clst) between the hydrate cage and the guest molecular cluster, and the interaction energy (ΔEclst) of the guest molecular cluster in the cage. (2) The energy term ΔEclst of the hydrogen molecular cluster in the hydrate cage is the only repulsive energy contribution (positive values) to the stability of the gas-hydrate cages, which increases with the number of hydrogen molecules and decreases with the size of the cage volume. (3) The strong hydrogen bond energy ΔEH-b remains constant in a broad range of 2.74 Å to 2.86 Å, in which the change in ΔEH-b is less than ±5 kJmol−1. (4) Capacity of hydrogen molecules in the hydrate cage depends on the volume of the hydrate cages. When the side length RO-O is 2.82 Å, at most 4 hydrogen molecules can be stored in the 512 cage. In large hydrate cages (51262 and 51264), more hydrogen molecules can be stored.
Abnormal global and local event detection in compressive sensing domain
Authors: Wang Tian , Qiao Meina , Chen Jie , Wang Chuanyun , Zhang Wenjia , Snoussi Hichem
Published: May 2018

Abnormal event detection, also known as anomaly detection, is one challenging task in security video surveillance. It is important to develop effective and robust movement representation models for global and local abnormal event detection to fight against factors such as occlusion and illumination change. In this paper, a new algorithm is proposed. It can locate the abnormal events on one frame, and detect the global abnormal frame. The proposed algorithm employs a sparse measurement matrix designed to represent the movement feature based on optical flow efficiently. Then, the abnormal detection mission is constructed as a one-class classification task via merely learning from the training normal samples. Experiments demonstrate that our algorithm performs well on the benchmark abnormal detection datasets against state-of-the-art methods.
The stretch to stray on time: Resonant length of random walks in a transient
Authors: Falcke Martin , Friedhoff Victor Nicolai
Published: May 2018

First-passage times in random walks have a vast number of diverse applications in physics, chemistry, biology, and finance. In general, environmental conditions for a stochastic process are not constant on the time scale of the average first-passage time or control might be applied to reduce noise. We investigate moments of the first-passage time distribution under an exponential transient describing relaxation of environmental conditions. We solve the Laplace-transformed (generalized) master equation analytically using a novel method that is applicable to general state schemes. The first-passage time from one end to the other of a linear chain of states is our application for the solutions. The dependence of its average on the relaxation rate obeys a power law for slow transients. The exponent ν depends on the chain length N like ν=−N/(N+1) to leading order. Slow transients substantially reduce the noise of first-passage times expressed as the coefficient of variation (CV), even if the average first-passage time is much longer than the transient. The CV has a pronounced minimum for some lengths, which we call resonant lengths. These results also suggest a simple and efficient noise control strategy and are closely related to the timing of repetitive excitations, coherence resonance, and information transmission by noisy excitable systems. A resonant number of steps from the inhibited state to the excitation threshold and slow recovery from negative feedback provide optimal timing noise reduction and information transmission.
Nonlinear localized modes in a plate of a layered superconductor
Authors: Apostolov S. S. , Kadygrob D. V. , Maizelis Z. A. , Nikolaenko A. A. , Yampol'skii V. A.
Published: May 2018

We present a theoretical study of nonlinear localized electromagnetic modes in a plate of a layered superconductor. Despite the symmetry of the system, the plate is assumed to be in a homogenous dielectric environment, with superconducting layers lying perpendicular to the plate surface and the modes propagating across the layers. Due to the nonlinearity of the Josephson plasma, the plate can contain localized modes that are symmetric, antisymmetric and nonsymmetric with respect to the magnetic field. It is shown that under certain conditions the dispersion of the localized modes can be anomalous whereas the group velocity vanishes. By virtue of the nonlinearity, the dispersion relations contain the amplitude of the localized mode. This opens the possibility of observing the stopping of mode light in a plate of a layered superconductor.
[Cu(aq)]2+ is structurally plastic and the axially elongated octahedron goes missing
Authors: Frank Patrick , Benfatto Maurizio , Qayyum Munzarin
Published: May 2018

High resolution (k = 18 Å−1 or k = 17 Å−1) copper K-edge EXAFS and MXAN (Minuit X-ray Absorption Near Edge) analyses have been used to investigate the structure of dissolved [Cu(aq)]2+ in 1,3-propanediol (1,3-P) or 1,5-pentanediol (1,5-P) aqueous frozen glasses. EXAFS analysis invariably found a single axially asymmetric 6-coordinate (CN6) site, with 4×Oeq = 1.97 Å, Oax1 = 2.22 Å, and Oax2 = 2.34 Å, plus a second-shell of 4×Owater = 3.6 Å. However, MXAN analysis revealed that [Cu(aq)]2+ occupies both square pyramidal (CN5) and axially asymmetric CN6 structures. The square pyramid included 4×H2O = 1.95 Å and 1×H2O = 2.23 Å. The CN6 sites included either a capped, near perfect, square pyramid with 5×H2O = 1.94 ± 0.04 Å and H2Oax = 2.22 Å (in 1,3-P) or a split axial configuration with 4×H2O = 1.94, H2Oax1 = 2.14 Å, and H2Oax2 = 2.28 Å (in 1,5-P). The CN6 sites also included an 8-H2O second-shell near 3.7 Å, which was undetectable about the strictly pyramidal sites. Equatorial angles averaging 94° ± 5° indicated significant departures from tetragonal planarity. MXAN assessment of the solution structure of [Cu(aq)]2+ in 1,5-P prior to freezing revealed the same structures as previously found in aqueous 1M HClO4, which have become axially compressed in the frozen glasses. [Cu(aq)]2+ in liquid and frozen solutions is dominated by a 5-coordinate square pyramid, but with split axial CN6 appearing in the frozen glasses. Among these phases, the Cu–O axial distances vary across 1 Å, and the equatorial angles depart significantly from the square plane. Although all these structures remove the dx2-y2, dz2 degeneracy, no structure can be described as a Jahn-Teller (JT) axially elongated octahedron. The JT-octahedral description for dissolved [Cu(aq)]2+ should thus be abandoned in favor of square pyramidal [Cu(H2O)5]2+. The revised ligand environments have bearing on questions of the Cu(i)/Cu(ii) self-exchange rate and on the mechanism for ligand exchange with bulk water. The plasticity of dissolved Cu(ii) complex ions falsifies the foundational assumption of the rack-induced bonding theory of blue copper proteins and obviates any need for a thermodynamically implausible protein constraint.
Patterning and manipulating microparticles into a three-dimensional matrix using standing surface acoustic waves
Authors: Nguyen T. D. , Tran V. T. , Fu Y. Q. , Du H.
Published: May 2018

A method based on standing surface acoustic waves (SSAWs) is proposed to pattern and manipulate microparticles into a three-dimensional (3D) matrix inside a microchamber. An optical prism is used to observe the 3D alignment and patterning of the microparticles in the vertical and horizontal planes simultaneously. The acoustic radiation force effectively patterns the microparticles into lines of 3D space or crystal-lattice-like matrix patterns. A microparticle can be positioned precisely at a specified vertical location by balancing the forces of acoustic radiation, drag, buoyancy, and gravity acting on the microparticle. Experiments and finite-element numerical simulations both show that the acoustic radiation force increases gradually from the bottom of the chamber to the top, and microparticles can be moved up or down simply by adjusting the applied SSAW power. Our method has great potential for acoustofluidic applications, building the large-scale structures associated with biological objects and artificial neuron networks.
Manipulating the magnetism and resistance state of Mn:ZnO/Pb(Zr0.52Ti0.48)O3 heterostructured films through electric fields
Authors: Li Yong-Chao , Wu Jun , Pan Hai-Yang , Wang Jue , Wang Guang-Hou , Liu Jun-Ming , Wan Jian-Guo
Published: May 2018

Mn:ZnO/Pb(Zr0.52Ti0.48)O3 (PZT) heterostructured films have been prepared on Pt/Ti/SiO2/Si wafers by a sol-gel process. Nonvolatile and reversible manipulation of the magnetism and resistance by electric fields has been realized. Compared with the saturation magnetic moment (Ms) in the +3.0 V case, the modulation gain of Ms can reach 270% in the −3.0 V case at room temperature. The resistance change is attributed to the interfacial potential barrier height variation and the formation of an accumulation (or depletion) layer at the Mn:ZnO/PZT interface, which can be regulated by the ferroelectric polarization direction. The magnetism of Mn:ZnO originates from bound magnetic polarons. The mobile carrier variation in Mn:ZnO, owing to interfacial polarization coupling and the ferroelectric field effect, enables the electric manipulation of the magnetism in the Mn:ZnO/PZT heterostructured films. This work presents an effective method for modulating the magnetism of magnetic semiconductors and provides a promising avenue for multifunctional devices with both electric and magnetic functionalities.
Electromagnetic fluctuations during guide field reconnection in a laboratory plasma
Authors: v. Stechow A. , Fox W. , Jara-Almonte J. , Yoo J. , Ji H. , Yamada M.
Published: May 2018

Electromagnetic fluctuations are studied during magnetic reconnection in a laboratory plasma for a range of guide magnetic fields from nearly zero up to normalized guide fields Bg/Bup=1.2. The predominant fluctuations are identified as right-hand polarized whistler modes, which become increasingly organized and less intermittent, and obtain larger amplitude with the increasing guide field. The fluctuation amplitude also increases with the reconnecting magnetic field, implying a relatively constant conversion of upstream magnetic energy to turbulent fluctuations of ≲1% across guide field strengths.
Efficient calculation of beyond RPA correlation energies in the dielectric matrix formalism
Authors: Beuerle Matthias , Graf Daniel , Schurkus Henry F. , Ochsenfeld Christian
Published: May 2018

We present efficient methods to calculate beyond random phase approximation (RPA) correlation energies for molecular systems with up to 500 atoms. To reduce the computational cost, we employ the resolution-of-the-identity and a double-Laplace transform of the non-interacting polarization propagator in conjunction with an atomic orbital formalism. Further improvements are achieved using integral screening and the introduction of Cholesky decomposed densities. Our methods are applicable to the dielectric matrix formalism of RPA including second-order screened exchange (RPA-SOSEX), the RPA electron-hole time-dependent Hartree-Fock (RPA-eh-TDHF) approximation, and RPA renormalized perturbation theory using an approximate exchange kernel (RPA-AXK). We give an application of our methodology by presenting RPA-SOSEX benchmark results for the L7 test set of large, dispersion dominated molecules, yielding a mean absolute error below 1 kcal/mol. The present work enables calculating beyond RPA correlation energies for significantly larger molecules than possible to date, thereby extending the applicability of these methods to a wider range of chemical systems.
Polydyne displacement interferometer using frequency-modulated light
Authors: Arablu Masoud , Smith Stuart T.
Published: May 2018

A radio-frequency Frequency-Modulated (FM) signal is used to diffract a He-Ne laser beam through an Acousto-Optic Modulator (AOM). Due to the modulation of the FM signal, the measured spectra of the diffracted beams comprise a series of phase-synchronized harmonics that have exact integer frequency separation. The first diffraction side-beam emerging from the AOM is selected by a slit to be used in a polydyne displacement interferometer in a Michelson interferometer topology. The displacement measurement is derived from the phase measurement of selected modulation harmonic pairs. Individual harmonic frequency amplitudes are measured using discrete Fourier transform applied to the signal from a single photodetector. Phase signals are derived from the changes in the amplitudes of different harmonic pairs (typically odd-even pairs) with the phase being extracted using a standard quadrature method. In this study, two different modulation frequencies of 5 and 10 kHz are used at different modulation depths. The measured displacements by different harmonic pairs are compared with a commercial heterodyne interferometer being used as a reference for these studies. Measurements obtained from five different harmonic pairs when the moving mirror of the interferometer is scanned over ranges up to 10 μm all show differences of less than 50 nm from the reference interferometer measurements. A drift test was also used to evaluate the differences between the polydyne interferometer and reference measurements that had different optical path lengths of approximately 25 mm and 50 mm, respectively. The drift test results indicate that about half of the differences can be attributed to temperature, pressure, and humidity variations. Other influences include Abbe and thermal expansion effects. Rough magnitude estimates using simple models for these two effects can account for remaining observed deviations.
Atomistic interpretation of the ac-dc crossover frequency in crystalline and glassy ionic conductors
Authors: Marple M. A. T. , Avila-Paredes H. , Kim S. , Sen S.
Published: May 2018

A comprehensive analysis of the ionic dynamics in a wide variety of crystalline and glassy ionic conductors, obtained in recent studies using a combination of electrochemical impedance and nuclear magnetic resonance spectroscopic techniques, is presented. These results demonstrate that the crossover frequency, between the frequency-independent dc conductivity and the frequency-dependent ac conductivity, corresponds to the time scale of “successful” diffusive hops of the mobile ions between the trapping sites in the structure. These inter-site hops are typically compound in nature and consist of several elementary hops in the intervening region between the neighboring trapping sites.
Tolman lengths and rigidity constants of multicomponent fluids: Fundamental theory and numerical examples
Authors: Aasen Ailo , Blokhuis Edgar M. , Wilhelmsen Øivind
Published: May 2018

The curvature dependence of the surface tension can be described by the Tolman length (first-order correction) and the rigidity constants (second-order corrections) through the Helfrich expansion. We present and explain the general theory for this dependence for multicomponent fluids and calculate the Tolman length and rigidity constants for a hexane-heptane mixture by use of square gradient theory. We show that the Tolman length of multicomponent fluids is independent of the choice of dividing surface and present simple formulae that capture the change in the rigidity constants for different choices of dividing surface. For multicomponent fluids, the Tolman length, the rigidity constants, and the accuracy of the Helfrich expansion depend on the choice of path in composition and pressure space along which droplets and bubbles are considered. For the hexane-heptane mixture, we find that the most accurate choice of path is the direction of constant liquid-phase composition. For this path, the Tolman length and rigidity constants are nearly linear in the mole fraction of the liquid phase, and the Helfrich expansion represents the surface tension of hexane-heptane droplets and bubbles within 0.1% down to radii of 3 nm. The presented framework is applicable to a wide range of fluid mixtures and can be used to accurately represent the surface tension of nanoscopic bubbles and droplets.
Increase of intrinsic emittance induced by multiphoton photoemission from copper cathodes illuminated by femtosecond laser pulses
Authors: An Chenjie , Zhu Rui , Xu Jun , Liu Yaqi , Hu Xiaopeng , Zhang Jiasen , Yu Dapeng
Published: May 2018

Electron sources driven by femtosecond laser have important applications in many aspects, and the research about the intrinsic emittance is becoming more and more crucial. The intrinsic emittance of polycrystalline copper cathode, which was illuminated by femtosecond pulses (FWHM of the pulse duration was about 100 fs) with photon energies above and below the work function, was measured with an extremely low bunch charge (single-electron pulses) based on free expansion method. A minimum emittance was obtained at the photon energy very close to the effective work function of the cathode. When the photon energy decreased below the effective work function, emittance increased rather than decreased or flattened out to a constant. By investigating the dependence of photocurrent density on the incident laser intensity, we found the emission excited by pulsed photons with sub-work-function energies contained two-photon photoemission. In addition, the portion of two-photon photoemission current increased with the reduction of photon energy. We attributed the increase of emittance to the effect of two-photon photoemission. This work shows that conventional method of reducing the photon energy of excited light source to approach the room temperature limit of the intrinsic emittance may be infeasible for femtosecond laser. There would be an optimized photon energy value near the work function to obtain the lowest emittance for pulsed laser pumped photocathode.
Performance limit of daytime radiative cooling in warm humid environment
Authors: Suichi Takahiro , Ishikawa Atsushi , Hayashi Yasuhiko , Tsuruta Kenji
Published: May 2018

Daytime radiative cooling potentially offers efficient passive cooling, but the performance is naturally limited by the environment, such as the ambient temperature and humidity. Here, we investigate the performance limit of daytime radiative cooling under warm and humid conditions in Okayama, Japan. A cooling device, consisting of alternating layers of SiO2 and poly(methyl methacrylate) on an Al mirror, is fabricated and characterized to demonstrate a high reflectance for sunlight and a selective thermal radiation in the mid-infrared region. In the temperature measurement under the sunlight irradiation, the device shows 3.4 °C cooler than a bare Al mirror, but 2.8 °C warmer than the ambient of 35 °C. The corresponding numerical analyses reveal that the atmospheric window in λ = 16 ∼ 25 μm is closed due to a high humidity, thereby limiting the net emission power of the device. Our study on the humidity influence on the cooling performance provides a general guide line of how one can achieve practical passive cooling in a warm humid environment.
Soft X-ray harmonic lasing self-seeded free electron laser at Pohang Accelerator Laboratory X-ray free electron laser
Authors: Nam Inhyuk , Min Chang-Ki , Kim Changbum , Yang Haeryong , Kim Gyujin , Heo Hoon , Kwon Soonnam , Park Sang Han , Kang Heung-Sik
Published: May 2018

The demonstration of a harmonic lasing self-seeded free-electron laser (HLSS FEL) scheme in the soft X-ray range at the Pohang Accelerator Laboratory X-ray Free Electron Laser is presented. We report the experimental results of HLSS FEL radiation with the shortest wavelength of 1 nm by using the optimized phase shift of 2/3π. The key feature of the HLSS scheme is that the mode number is decreased (the longitudinal coherence length is enhanced) which is directly observed using a single-shot spectrometer. The spectral brightness is enhanced by a factor of 1.7 compared to the self-amplified spontaneous emission FEL because of the narrowed bandwidth. Our results show a good agreement with the theoretical expectation and simulations. The HLSS mode is a promising standard operation mode to generate a stable and high-brightness X-ray FEL that will provide more benefits to users for various applications.
Effect of growth interruption in 1.55 μm InAs/InAlGaAs quantum dots on InP grown by molecular beam epitaxy
Authors: Jung Daehwan , Ironside Daniel J. , Bank Seth R. , Gossard Arthur C. , Bowers John E.
Published: May 2018

We report the effect of growth interruptions on the structural and optical properties of InAs/InAlGaAs/InP quantum dots using molecular beam epitaxy. We find that the surface quantum dots experience an unintended ripening process during the sample cooling stage, which reshapes the uncapped InAs nanostructures. To prevent this, we performed a partial capping experiment to effectively inhibit structural reconfiguration of surface InAs nanostructures during the cooling stage, revealing that InAs nanostructures first form quantum dashes and then transform into quantum dots via a ripening process. Our result suggests that the appearance of buried InAs/InAlGaAs nanostructures can be easily misunderstood by surface analysis.