bluuebunny/crossref_metadata_2025 huggingface dataset:
Attempts to replace nut coke with semi-coke for blast furnace ironmaking
Authors: Meng Qingbo , Meng Fanyu , Zhan Li , Xu Xiuli , Yu Jianglong , Wang Qi
Published: April 2021

Low coke rate for blast furnace operation has been required in response to the rising cost of coking coals. To extend the utilisation of coal resources, semi-coke has been introduced to blast furnace ironmaking process in recent years, however, there are still many issues unclear about the effect of semi-coke on ironmaking process. In this study, the possibilities of using semi-coke as alternative fuel for nut coke were studied. The characteristics of semi-coke including mechanical strength, high-temperature strength/reactivity, carbon gasification as well as direct reduction were studied and compared with small size metallurgical cokes (nut cokes). The results showed that semi-coke has higher CRI values, especially at higher temperatures and in a mix-charging pattern. Semi-coke was found to have a higher gasification reaction rate and depleted at lower temperatures. The reduction results showed that with participating of semi-coke the reaction starts at lower temperatures. In addition, the study suggested that semi-coke exhibits the advantages of low ash and sulphur contents, although it has lower mechanical strength, it would protect the lump coke by shifting the carbon gasification to itself, therefore, mixing semi-coke would benefit the blast furnace operation and lower the coke rate.
Konzepte zu Diagnose, Verlaufs- und Sturzrisikobeurteilung bei neurologischen Gangstörungen
Authors: Wuehr Max , Jooshani Nima , Schniepp Roman
Published: April 2021

Die quantitative Ganganalyse findet zunehmend Einsatz bei der Diagnose, Verlaufsbeurteilung und Risikostratifizierung von neurologischen Gangstörungen. Dabei bleibt oft unklar, welche Messtechnik, Untersuchungsbedingungen und Gangmerkmale geeignet sind, um bestimmte klinische Fragestellungen zu beantworten. Ziel dieses Überblicksartikels ist es, allgemein anwendbare Konzepte und Strategien für die Testung, Analyse und Interpretation der Gangfunktion im klinischen Kontext vorzustellen und ihre Anwendung nah an der klinischen Praxis zu illustrieren. Der erste Abschnitt des Artikels gibt einen Überblick über derzeit verfügbare stationäre und mobile Messtechnologien, die eine Testung von Gang im klinischen Bereich und eine kontinuierliche Erfassung von Mobilität im Alltag der Patienten ermöglichen. Zudem werden Strategien zur Auswahl geeigneter Untersuchungsprotokolle diskutiert und Konzepte vorgestellt, die die Parametrisierung von Gang vereinfachen. Die anschließenden Abschnitte widmen sich konkreten klinischen Anwendungsfeldern der quantitativen Ganganalyse: Anhand von Fallbeispielen aus der aktuellen Studienliteratur wird dargestellt, (1) wie spezifische Muster des Gangbefunds Orientierungspunkte für die Differenzialdiagnose bieten und (2) wie quantitative Gangmerkmale die Früherkennung, Verlaufsbeurteilung und das Therapiemonitoring bei neurologischen Gangstörungen unterstützen können. Abschließend wird (3) der Beitrag von stationärer Gangtestung und mobiler Mobilitätserfassung für die Sturzrisikoprognose bei Patienten mit neurologischen Gangstörungen diskutiert.
COVID-19 Pandemic—What Should Not Be Forgotten
Authors: Koechlin Luca
Published: April 2021

The Swiss Society of Cardiac Surgery (SGHC) has announced a “Special Swiss Young Cardiac Surgeon Award 2020,” with the aim to learn more about the consequences of the coronavirus disease 2019 (COVID-19) pandemic for young Swiss cardiac surgeons. Therefore, the overall goal of this article is to highlight the personal situation and perspective of a young Swiss cardiac surgeon in training during the COVID-19 pandemic. This article reflects the personal opinion of a young Swiss cardiac surgeon discussing the impact of the pandemic for young surgeons in training and potential chances and learning effects.
Comparison of Simulation-Based versus Cadaveric-Tissue-Based Ocular Trauma Training on Novice Ophthalmologists: Repair of Corneal Laceration Model
Authors: Purt Boonkit , Ducey Timothy , Sykes Sean , Pasternak Joseph F. , Ryan Denise S. , Sia Rose K. , Colyer Marcus H.
Published: April 2021

Purpose The aim of this study was to evaluate whether the simulated tissue models may be used in place of animal-based model for corneal laceration repair for surgical skills acquisition.

Design Prospective randomized controlled trial.

Participants Seventy-nine military and civilian 2nd- and 3rd-year ophthalmology residents and 16 staff ophthalmologists participating in the Tri-Service Ocular Trauma Skills Laboratory at the Uniformed Services University (Bethesda, MD).

Methods Resident ophthalmologists underwent preliminary evaluation of their ability to close a 5-mm linear, full-thickness corneal laceration involving the visual axis. They then were randomized to undergo 90 to 120 minutes of either simulator-based (SIM) or swine cadaveric-tissue-based (CADAVER) corneal laceration repair. The same evaluation was performed post training. On a more limited basis, the study was repeated for attending ophthalmologists to act as a pilot for future analysis and test efficacy for “refresher” training.

Main Outcome Measures Successful wound closure with secondary outcomes of suture length, tension, depth, and orientation, as graded by attending ophthalmologists.

Results No significant difference in CADAVER versus SIM groups in the primary outcome of watertight wound closure of the corneal laceration. CADAVER group performed better than SIM group for certain metrics (suture depth, p = 0.009; length, p = 0.003; and tension, p = 0.043) that are associated with poor wound closure and increased amount of induced corneal astigmatism. For attending ophthalmologists, six of the eight in each group (SIM and CADAVER) retained or improved their skills.

Conclusions For resident ophthalmologists, SIM training is sufficient for achieving the primary outcome of watertight wound closure. However, CADAVER training is superior for wound metrics for the ideal closure. For attending ophthalmologists, SIM training may be useful for retention of skills.
Local and Regional Blocks for Complex Facial Wound Repair
Authors: Obokhare Joy
Published: April 2021

The location, severity, and associated injuries of the head and neck trauma dictate the type and treatment location needed for that particular patient. An in-depth knowledge of local and regional block options is vital to the proper management of facial wounds at the bedside, decreasing need for general anesthesia, anesthesia-related complication, length of hospital stay, and overall hospital costs. This article will discuss local and regional block options for the upper-face, midface, and lower face including dentition; complications of local and regional blocks and how to prevent them; and recent advances in local anesthesia. In addition, conscious sedation as an adjunct to local/regional blocks in children or patients with special needs will be discussed.
Reconstruction of the Mandibular Condyle
Authors: Anderson Spencer R. , Pak Kaitlynne Y. , Vincent Aurora G. , Ong Adrian , Ducic Yadranko
Published: April 2021

The mandibular condyle is an integral structure in the temporomandibular joint (TMJ) serving not only as the hinge point for mandibular opening, but also facilitating mandibular growth and contributing to facial aesthetics. Significant compromise of the TMJ can be debilitating functionally, psychologically, and aesthetically. Reconstruction of the mandibular condyle is rarely straightforward. Multiple considerations must be accounted for when preparing for condylar reconstruction such as ensuring eradication of all chronically diseased or infected bone, proving clear oncologic margins following tumor resection, or achieving stability of the surrounding architecture in the setting of a traumatic injury. Today, there is not one single gold-standard reconstructive method or material; ongoing investigation and innovation continue to improve and transform condylar reconstruction. Herein, we review methods of condylar reconstruction focusing on autologous and alloplastic materials, surgical techniques, and recent technological advances.
Drawing Reproducible Conclusions from Observational Clinical Data with OHDSI
Authors: Hripcsak George , Schuemie Martijn J. , Madigan David , Ryan Patrick B. , Suchard Marc A.
Published: April 2021

Objective: The current observational research literature shows extensive publication bias and contradiction. The Observational Health Data Sciences and Informatics (OHDSI) initiative seeks to improve research reproducibility through open science.

Methods: OHDSI has created an international federated data source of electronic health records and administrative claims that covers nearly 10% of the world’s population. Using a common data model with a practical schema and extensive vocabulary mappings, data from around the world follow the identical format. OHDSI’s research methods emphasize reproducibility, with a large-scale approach to addressing confounding using propensity score adjustment with extensive diagnostics; negative and positive control hypotheses to test for residual systematic error; a variety of data sources to assess consistency and generalizability; a completely open approach including protocol, software, models, parameters, and raw results so that studies can be externally verified; and the study of many hypotheses in parallel so that the operating characteristics of the methods can be assessed.

Results: OHDSI has already produced findings in areas like hypertension treatment that are being incorporated into practice, and it has produced rigorous studies of COVID-19 that have aided government agencies in their treatment decisions, that have characterized the disease extensively, that have estimated the comparative effects of treatments, and that the predict likelihood of advancing to serious complications.

Conclusions: OHDSI practices open science and incorporates a series of methods to address reproducibility. It has produced important results in several areas, including hypertension therapy and COVID-19 research.
Surgical Outcomes of Non-Small Cell Lung Cancer in Single-Zone N2 in the Aortopulmonary Zone
Authors: Lee Kanghoon , Jeong Yong Ho , Ryu Jin-Sook , Kim Yong-Il , Kim Hyeong Ryul , Park Seung-Il
Published: April 2021

Objectives We evaluate the surgical outcome of clinically single-zone N2 lung cancer limited to aortopulmonary zone (AP zone; lymph node #5 or #6).

Patients and Methods We performed a retrospective analysis of patients with non-small cell lung cancer, in whom mediastinal lymph node metastasis was confined to AP zone.

Results A total of 84 patients who underwent upfront surgery were included in final analysis. Among these patients, pathological nodal outcomes were pN0–1 in 27 patients (32.1%), pN2a in 31 (36.9%), and pN2b in 26 (31.0%). In multivariate analysis, adenocarcinoma (p = 0.005) and staging workup without endobronchial ultrasound-transbronchial needle aspiration (p = 0.002) were independent risk factors for unexpected pN2b. The 5-year overall survival (OS) and disease-free survival (DFS) were 55.9 and 54.4%, respectively. There was no survival difference among patients with pN0–1, pN2a, and pN2b (p = 0.717). In survival analysis, there were no significant risk factors for OS. However, female sex and the ratio of positive lymph nodes to removed lymph nodes were significant risk factors for DFS in multivariate analysis (p = 0.032 and p = 0.009).

Conclusion In this study, cN2a in the AP zone with current diagnostic tool exhibited a relatively high false-positive rate (cN2/pN0–1; 32.1%). However, despite the possibility of pN2b, there were no significant differences in survival outcome according to the pathologic nodal stage.
Reproducibility of the Edinburgh Postnatal Depression Scale during the Postpartum Period
Authors: Ezirim Nkechi , Younes Lena K. , Barrett Joel H. , Kauffman Robert P. , Macleay Katie J. , Newton Scott T. , Tullar Paul
Published: April 2021

Objective This study was aimed to evaluate the efficacy of the Edinburgh Postnatal Depression Scale (EPDS) in the immediate postpartum period, which we defined as between 3 and 24 hours postpartum for the purpose of this research. This is such that if it can predict scores obtained at the postpartum visit, it will be an opportunity to access psychiatric services for the patient that may otherwise be more difficult to access in the outpatient setting.

Study Design Longitudinal observational study, which included an analysis of 848 consecutive participants screened with the EPDS in the hospital and at the 6-week postpartum visit.

Results Receiver-operating characteristic (ROC) curve suggested >3 at delivery as a more optimal score to predict depression at the postpartum visit with sensitivity 76.5% and specificity 65.9%. The commonly accepted EPDS cut-off value of >9 was far less sensitive at 28.8% but reasonably specific at 93.2% for predicting elevated scores (>9) 6 weeks postpartum. In subgroup analysis, only a prior mental health disorder was found to be predictive of elevated scores at the postpartum visit (relative risk: 1.97, 95% confidence interval: 1.17–3.32, p = 0.01).

Conclusion The EPDS, originally designed to screen for postpartum depression (PPD) in the outpatient setting, does not predict the development of PPD, as determined by the EPDS (validated at the 6-week postpartum time interval) when administered during hospitalization shortly after delivery.

Key Points
Peripherally Inserted Central Venous Catheters Provide Safe and Easy Central Venous Access in Patients with Head and Neck Cancer
Authors: Sato Ryosuke , Kumai Takumi , Hayashi Ryusuke , Komatsuda Hiroki , Kishibe Kan , Takahara Miki , Katada Akihiro , Hayashi Tatsuya , Harabuchi Yasuaki
Published: April 2021

Purpose The use of peripherally inserted central venous catheters (PICCs) has increased recently; several reports have revealed that they can be easily and safely used in patients with various diseases. However, there are few reports on the use of PICCs in patients with head and neck cancer. This study was aimed at evaluating the safety and feasibility of use of PICCs in patients with head and neck cancer.

Materials and Methods We retrospectively analyzed the date of 118 PICC insertions in 85 patients with head and neck cancer from January 2014 to December 2017. The PICCs have been placed under ultrasound guidance in all cases.

Results The PICC puncture success rate was 95.2%. Catheter-related bloodstream infection occurred in four cases. The most common complication necessitating PICC removal was suspected catheter-related bloodstream infection (24 cases). All cases with confirmed and suspected catheter-related bloodstream infection improved with administration of antimicrobial agents. Phlebitis occurred in five cases, in all of whom the PICC placement had been made via an antecubital vein; the condition improved without treatment in all five cases. Deep vein thrombosis occurred in two cases, both of which improved with oral anticoagulant therapy.

Conclusion This study demonstrated that the complications associated with ultrasound-guided PICC insertion are manageable, and improve with conservative treatment in the majority of cases. Therefore, use of PICCs may be considered for easy and safe central venous access in patients with head and neck cancer, because the insertion success rate was acceptable.
A lift of the Seiberg–Witten equations to Kaluza–Klein five-manifolds
Authors: Hamilton Mark J. D.
Published: April 2021

We consider Riemannian four-manifolds X,gX with a spinc-structure and a suitable circle bundle Y over X such that the spinc-structure on X lifts to a spin-structure on Y. With respect to these structures, a spinor ϕ on X lifts to an untwisted spinor ψ on Y and a U1-gauge field A for the spinc-structure can be absorbed into a Kaluza–Klein metric gYA on Y. We show that irreducible solutions A,ϕ to the Seiberg–Witten equations on X,gX for the given spinc-structure are equivalent to irreducible solutions ψ of a Dirac equation with cubic non-linearity on the Kaluza–Klein circle bundle Y,gYA. As an application, we consider solutions to the equations in the case of Sasaki five-manifolds, which are circle bundles over Kähler–Einstein surfaces.
Dynamics of moving electron vortices and magnetic ring in laser plasma interaction
Authors: Yue D. N. , Chen M. , Geng P. F. , Yuan X. H. , Weng S. M. , Bulanov S. S. , Bulanov S. V. , Mima K. , Sheng Z. M. , Zhang J.
Published: April 2021

Moving electron vortices have been observed in laser interaction with non-uniform near-critical-density plasma by multi-dimensional Particle-in-Cell simulations. In two dimensional geometry, there are two vortices with opposite magnetic polarity, moving perpendicularly to the plasma density gradient direction. The field distribution and particle motion composing such a moving structure have been clearly observed in simulations, which explains the vortex motion. Two components of loop currents are formed around each electron vortex, which dominate the vortex motion. The moving velocity can be as large as a 0.2c level, forming relativistic vortices inside the plasma. Laser plasma conditions such as intensity, polarization, density profile, and external magnetic field effects on the vortex motion and evolution are also studied. In three dimensions, the structure appears as an expanding magnetic ring with an internal magnetic field up to 1000 Tesla. Such vortex structures suggest an interesting way of energy (with more than 5% of the laser energy) transportation to ambient plasmas as far as 50 μm away from the laser-plasma interaction region, which may have applications in laser plasma-based inertial confinement fusion and laboratory astrophysics.
Nanoscale InN clusters and compositional inhomogeneities in InGaN epitaxial layers quantified by tip-enhanced Raman scattering
Authors: Seidlitz D. , Poliani E. , Ries M. , Hoffmann A. , Wagner M. R.
Published: April 2021

We investigate the compositional homogeneity of InGaN thin films with a high In content grown by migration-enhanced plasma-assisted metal-organic chemical vapor deposition. Micro-Raman spectroscopy and tip-enhanced Raman spectroscopy (TERS) are used to analyze the local InGaN composition on the micro- and nanoscale. Based on conventional micro-Raman mapping, the InGaN composition for all samples appears uniform but shows indications for intrinsic phase separations. TERS, a nanoscopic technique with a high spatial resolution far below the diffraction limit, verifies the formation of nanoscale compositional inhomogeneities. The dimensions of these compositional fluctuations observed in TERS are confirmed by scattering-type scanning near-field infrared nanoscopy (s-SNIN). In contrast to s-SNIN, we show that TERS furthermore enables the quantification of the In content in the different compositional regions and even allows the identification of InN nanoclusters near the surface of the epitaxial films.
Disruption avoidance via radio frequency current condensation in magnetic islands produced by off-normal events
Authors: Reiman A. H. , Bertelli N. , Fisch N. J. , Frank S. J. , Jin S. , Nies R. , Rodriguez E.
Published: April 2021

This paper discusses the use of radio frequency (RF) current drive to stabilize large islands, focusing on nonlinear effects that appear when relatively high powers are used to stabilize large islands. We are interested in developing a capability to stabilize large islands via RF driven currents to avoid the need for mitigation to the extent possible. As tokamaks are designed and built with increasing levels of stored energy in the plasma, disruptions become increasingly dangerous. It has been reported that 95% of the disruptions in the Joint European Torus tokamak with the ITER-like wall are preceded by the growth of large locked islands. These large islands are mostly produced by off-normal events other than neoclassical tearing modes. This paper presents theory and modeling for a nonlinear “RF current condensation” effect that can concentrate the RF driven current near the center of a large island, thereby increasing the efficiency of the stabilization. A nonlinear shadowing effect can hinder the stabilization of islands if the aiming of the ray trajectories does not properly consider the nonlinear effects.
A universal criterion for the failure threshold in slowly sheared bulk metallic glasses
Authors: Luo Y. S. , Wang Z. , Eckert J. , Qiao J. W.
Published: April 2021

A theory, bridging the free-volume and shear-transformation zone concepts through mean field theory, is established to predict the failure threshold of bulk metallic glasses (BMGs), and the physical mechanism of slip is investigated. A linear relation between the increment of free-volume and strain rate at small time intervals is found to describe inhomogeneous flow. The room-temperature theoretical failure threshold, Smax, follows a universal material-dependent criterion Smax∼Tgη, where Tg is the glass-transition temperature and η is a constant related to the serrated flow. This criterion is in good accordance with experimental results and provides a quantitative understanding of the failure mechanisms highly dependent on the serrations in BMGs, which is helpful to enhance plasticity via tuning the failure threshold.
Room-temperature two-terminal magnetoresistance ratio reaching 0.1% in semiconductor-based lateral devices with L21-ordered Co2MnSi
Authors: Kudo K. , Yamada M. , Honda S. , Wagatsuma Y. , Yamada S. , Sawano K. , Hamaya K.
Published: April 2021

We report on the highest two-terminal magnetoresistance (MR) ratio at room temperature in semiconductor-based lateral spin-valve devices. From first-principles calculations, we predict energetically stable ferromagnet–semiconductor heterointerfaces consisting of Co2MnSi (CMS) and Ge(111) upon insertion of Fe atomic layers. Using low-temperature molecular beam epitaxy, we demonstrate L21-ordered CMS epilayers at 80 °C on Ge(111), where the CMS layer can be utilized as a spin injector and detector. Two-terminal MR ratios as high as 0.1% are achieved in n-Ge-based lateral spin-valve devices with CMS/Fe/Ge Schottky tunnel contacts annealed at 200 °C. This study will open a path for semiconductor-based spintronic devices with a large MR ratio at room temperature.
Disorder and epitaxial strain control of metamagnetic transition, large saturation magnetization, and magneto-terahertz properties of YMn0.5Cr0.5O3 polycrystals and thin films
Authors: Vagadia Megha , Prajapati G. L. , Kartikeyan Tannu , Othayoth Aswitha , Rana D. S.
Published: April 2021

The multiferroic YMn0.5Cr0.5O3 (YMCO) compound possesses magnetic phases that are debatable for their origin in intrinsic and extrinsic attributes. To extract the contribution of the polycrystalline disorder as well as determine the effect of structural modifications and epitaxial strain on the magnetic properties, we have formed YMCO bulk in polycrystalline pellet and powder forms, and epitaxial thin films with a wide range of compressive and tensile strains. The temperature and field dependent magnetization of polycrystals discards the possibility of magnetization reversal and unveils the presence of multidomain states with soft and hard characters in powder form. The epitaxial YMCO films possess an extraordinary structural control of their magnetic properties, as the tuning of compressive strain results in an increase of 4–5 factors of magnitude in the saturation magnetic moment. This strain engineering further allows a tuning of the magnetic property from spin frustration/short-range ordering to the long-range ordering, which also induces a rare phenomenon of sharp step-like metamagnetic transition. The implementation of magneto-terahertz time-domain spectroscopy on this system does not show the manifestation of any magnon/electromaganon resonance typical of a magnetoelectric phase, thus suggesting either a very weak or lack of coupling between magnetic and electric ordered parameters in polycrystalline YMCO. This study resolves some longstanding issues on the magnetic and magnetoelectric phases in addition to the epitaxial control of large magnetization and metamagnetic transition being potentially relevant in several aspects of spintronics applications.
Identification of TO and LO phonons in cubic natBP, 10BP and 11BP crystals
Authors: Zhu Siqi , Zheng Wei , Lu Xuefang , Cheng Lu , Zhong Wenbin , Huang Feng
Published: April 2021

Cubic boron phosphide (BP) has the physical advantages of ultra-high hardness, high melting point, and high thermal conductivity, which make it greatly potential in device applications under extreme conditions. However, there are still problems about phonon identification of BP with a curious phenomenon found in the Raman spectra of isotopic lattice (the small peak in the Raman spectra of natBP almost or completely disappears in the Raman spectra of isotopic lattice). Faced with this problem, here we report the extremely narrow reststrahlen bands of natBP, 10BP, and 11BP single crystals via infrared reflectance spectrum different from that of cubic BN, α-GaN, and 4H–SiC, and identify their transverse optical phonon (TO) and longitudinal optical phonon (LO), which breaks traditional understanding in this aspect. Through the classical phonon polariton model fitting, the TO-LO splitting in three BP crystals is calculated less than 3 cm−1, which is attributed to their weak ionicity. This research helps to identify the Raman spectra of BP, where the strongest Raman peak is found as a mixed mode of TO(Γ) and LO(Γ).
Defining the primary business measure of liveweight production for beef cows in northern Australia
Authors: Fordyce Geoffry , Barnes Tamsin S. , McGowan Michael R. , Perkins Nigel R. , Smith David R. , McCosker Kieren D.
Published: April 2021

Context Annual liveweight production of a cow is the sum of the weight of its calf at weaning and its own annual liveweight change. Along with value per kg, annual liveweight production constitutes the business income contributed by the animal; however, it is not well described for north Australian beef herds. Aims This study aimed to quantify cow liveweight production and to measure impacts of reproduction and other risk factors. Methods Liveweight production data from 2122 Brahman and tropically adapted composite cows aged 2.5–8.5 years and grazing the four primary country types in northern Australia were analysed as a function of current and previous mating outcomes, mating age, breed, hip height, and body condition or liveweight. Key results Cow liveweight production was highly variable (coefficient of variation 40%) among and within years. Liveweight production of cows averaged 154 kg/year from their first mating, 168 kg/year from their second, and 190 kg/year from subsequent matings; however, production efficiency remained constant, with a liveweight production ratio of 0.31–0.32 kg produced annually per kg of grazing animal. Within environment, average weaner production (kg/cow) approximated the estimated average annual weight gain of yearling cattle. Weight of calves weaned contributed ~87% of annual liveweight production. Liveweight production averaged 103–143 kg higher for cows that weaned a calf than those that lost a calf, with the effect greater in older cows (P < 0.001). Liveweight production averaged 39–43 kg higher for non-pregnant cows than those that lost a calf (P < 0.001). These effects were attenuated by ~20% over a lifetime. Cows weaning a calf from a previous mating had liveweight production 57–85 kg higher (P < 0.001) than those not weaning a calf, having begun the year in poorer condition because of lactation. Calf weaning weight was 25 kg higher in mature cows than in first- and second-lactation cows. Liveweight production advantages of tropical composites over Brahmans appeared primarily associated with consistently higher calf weaning weights, and higher cow growth during their first reproductive year. Conclusions This research successfully demonstrated the concept of liveweight production in breeding beef cows, showing it to be primarily governed by available nutrition and mating outcome. Implications These findings provide a previously unavailable reference point for beef-systems management in northern Australia; for example, liveweight production could be used to determine the potential achievable increases in cow performance for a specific nutritional environment.
Direct validation of dune instability theory
Authors: Lü Ping , Narteau Clément , Dong Zhibao , Claudin Philippe , Rodriguez Sébastien , An Zhishan , Fernandez-Cascales Laura , Gadal Cyril , Courrech du Pont Sylvain
Published: April 2021

Significance

We report a landscape-scale experiment with controlled initial and boundary conditions to reveal incipient dune growth under natural action of wind. We measured growth rate of dunes of different wavelengths for 42 mo in a desert plot of 7,500m2. We identify an early phase in which a clear maximum growth rate occurs for a 15-m dune spacing. Successful comparison with dune instability theory allows us to quantify the size-selection mechanism leading to the emergence of periodic dune patterns, which can be directly related to flow and sand transport properties. An experiment of this type and scale is unprecedented. Its results boost confidence in the existing theory, confirming its application to a variety of planetary landscapes from repeated aerial/orbital imagery.
Platinum(II)
N
-heterocyclic carbene complexes arrest metastatic tumor growth
Authors: Wan Pui-Ki , Tong Ka-Chung , Lok Chun-Nam , Zhang Chunlei , Chang Xiao-Yong , Sze Kong-Hung , Wong Alice Sze Tsai , Che Chi-Ming
Published: April 2021

Significance

Metastasis is a common cause of cancer mortality yet a daunting challenge in oncology. We have discovered a cytotoxic platinum(II)
N
-heterocyclic carbene complex that not only suppressed primary tumor growth in mice but also impeded metastatic growth of breast cancer and melanoma with long-term tolerance attributable to its eventual biotransformation into less-toxic, excretable products. It directly engages the cytoskeletal protein vimentin that plays pivotal roles in cancer stemness, survival, and invasion. It binds vimentin noncovalently via the distinct structural scaffold with a dissociation constant of 1 µM as determined by surface plasmon resonance, NMR, and molecular dynamics simulations, revealing the significance of harnessing noncovalent interactions of metal compounds with important molecular targets in the development of new anticancer metal medicines.
Structural basis for backtracking by the SARS-CoV-2 replication–transcription complex
Authors: Malone Brandon , Chen James , Wang Qi , Llewellyn Eliza , Choi Young Joo , Olinares Paul Dominic B. , Cao Xinyun , Hernandez Carolina , Eng Edward T. , Chait Brian T. , Shaw David E. , Landick Robert , Darst Seth A. , Campbell Elizabeth A.
Published: April 2021

Significance

The COVID-19 pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 genome is replicated and transcribed by its RNA-dependent RNA polymerase (RdRp), which is the target for antivirals such as remdesivir. We use a combination of approaches to show that backtracking (backward motion of the RdRp on the template RNA) is a feature of SARS-CoV-2 replication/transcription. Backtracking may play a critical role in proofreading, a crucial process for SARS-CoV-2 resistance against many antivirals.
Production de tilapia marin en circuit ferme en eau verte: le Système Aquacole à Recyclage Integral (SARI).
Authors: Wilde Nicolas de , Gilles Sylvain
Published: April 2021

The Integral Recycling Aquaculture System (SARI) is an artificial ecosystem that combines closed-circuit farming of marine tilapia Sarotherodon melanotheron heudelotii with plankton lagooning in brackish water. Compared to conventional closed circuits in clear water, it provides significant advantages in terms of fresh water and energy savings, as well as in terms of health by limiting the introduction of pathogens. A prototype of the SARI located at the IRD Center in Mbour, Senegal, has made it possible to study the functioning of this breeding system. The tilapia S. m. heudelotii, when raised in intensive or semi-intensive mode, promotes the production of the green algae Chlorella sp. which purifies the environment of nitrogenous waste produced by fish. The algal population is regulated by the production of the rotifer Brachionus plicatilis, which itself serves as a complementary feed for the fry in rearing.
Production of marine tilapia in a green-water, closed system in Senegal: the integrated recycling aquaculture system.
Authors: de Wilde Nicolas , Gilles Sylvain
Published: April 2021

The Integrated Recycling Aquaculture System (Système Aquacole à Recyclage Intégral, or SARI) is a photosynthetic suspended growth system that combines rearing of euryhaline tilapia (Sarotherodon melanotheron heudelotii) with a recirculating brackish planktonic wastewater treatment. Compared with classical clear-water closed recirculating systems, it brings important advantages in terms of fresh water and energy savings, and biosecurity, by limiting invasion and growth of pathogens. A prototype of SARI was installed and studied at the IRD Centre at Mbour, Senegal. When reared in intensive or semi-intensive conditions, S. melanotheron heudelotii enhances production of green algae, Chlorella spp., which reduce the water levels of ammonia from fish excretion. The algae population is controlled by the rotifer, Brachionus plicatilis, which is also fed to reared fingerlings.
Case study on the National Aquaculture Strategic Plan in Malawi.
Authors: Banda Lisungu E. , Kang'ombe Jeremiah , Kaunda Emmanuel K. W.
Published: April 2021

This case study provides an analysis of the implementation of the National Aquaculture Strategic Plan (NASP) for Malawi. The NASP is a strategic document for aquaculture development in Malawi that was created in response to a request from the Government of Malawi (GoM) to the Japan International Cooperation Agency (JICA) to conduct a Master Plan Study on Aquaculture Development. The NASP was set to improve aquaculture development from 2005 to 2015. The aquaculture sector plays a significant role as a source of food, income and employment to Malawi's population. It is estimated that the sector provides about 2% of the nation's fish production and, among fish farming households, to contribute up to 17% of household income, depending on fish farming activities. Fish from both aquaculture and capture fisheries contribute about 4% to the country's GDP and provide almost 70% of animal protein and 40% of total protein thereby contributing to the country's food security and livelihood strategies. The purpose of the case study was to provide a clear understanding of the existing state of the NASP. The case study involves a number of stakeholders that were chosen randomly from the NASP document as partners in its implementation. The study analyses the progress of the NASP implementation by looking at whether the implementation structure was functioning, it also assessed the knowledge of the stakeholders on the document, the linkage of the stakeholders, the coordination among stakeholders and developments in fish production through aquaculture. The results show that the institutional structures that were proposed to implement and monitor all the NASP strategies and activities have not been formed. This has led to lack of knowledge of the document by some stakeholders. Poor coordination and networking among the stakeholders has also led to the failure of the strategic plan. The case study concludes that there is an urgent need for the formulation of a separate institutional structure to look into aquaculture development in Malawi with the help of the Departement of Fisheries (DoF) and all the stakeholders so as to help review and process the NASP action plans if quantitative progress is to be achieved.
Development of seaweed cultivation in Tanzania: the role of the University of Dar es Salaam and other institutions.
Authors: Msuya Flower E
Published: April 2021

Seaweed farming in Tanzania was initiated through research by a University of Dar es Salaam (UDSM) professor in the 1970s and early 1980's. This was followed by commercial cultivation, which was started by private entrepreneurs in 1989. By 1996 seaweed was being farmed all along the coast of Tanzania. Production in 2008 was 6000-7000 tonnes annually, with Eucheuma denticulatum and Kappaphycus alvarezii as the main cultivated species. Tanzanian seaweed is exported mainly to the USA, France, Denmark, and Spain. While UDSM continues to play a big role in this industry through research and development working with coastal communities, the government and other institutions also play a big role in not only research and development but also uniting farmers and exporters, and providing extension service. This case study looks at the start and running of the seaweed farming industry and the role of the UDSM and other institutions on the development of seaweed farming in Tanzania.
History and development of shellfish cultivation in Walvis Bay, Namibia.
Authors: Mapfumo Blessing
Published: April 2021

Namibia is one of the countries in Africa with a favourable natural environment for mariculture operations, particularly shellfish production. The nutrient-rich Benguela upwelling system of the Atlantic Ocean gives the Namibian coast a competitive advantage over other worldwide producers of shellfish, especially, oysters, mussels, abalone, scallops and others. Walvis Bay is Namibia 's biggest harbour town on the western Atlantic coast, where a well established commercial fisheries industry exists along side the country's largest mariculture centre. Other centres of mariculture production include Luderitz, (another fishing town on the southernmost part of the coastline), Swakopmund (30 km from Walvis Bay) and Henties Bay (100 km from Walvis Bay). Shellfish production in Walvis Bay is principally oyster farming and the species produced are the Pacific Oyster (Crassotrea gigas) and the European flat oyster (Ostrea edulis). These have been described as the best oysters in the world due to their exceptional taste and favourable meat-to-shell ratio (Hempel, 2006) and Namibia was ranked amongst the top 20 world leading exporters of oysters (FAO FishSTAT Commodities and Trade, 2006). However, production in 2008 significantly declined due to unexpected harmful algal blooms, the so called red tide phenomenon that resulted in the death of over 75% of all farmed oyster stock. Farmers are currently recuperating from this catastrophe. Besides oysters, mariculture production of other shellfish species in Walvis Bay is negligible but includes the Black mussel (Choromytilus meridionalis), the indigenous clams (Venerupis spp), indigenous scallops (Pecten spp). Cultivation of other shellfish such as abalone (Haliotis midae) and finfish such as Cobia (Rachycentron canadum), dusky kob (Argyrosomus japonicus) and turbot (Psetta maxima) is still being investigated. So far, the mariculture of shellfish in Walvis Bay is believed to have created over 120 jobs, both directly and indirectly.
Elevage en eau recyclée du poisson-chat africain Clarias gariepinus au Bénin: historique et situation actuelle de la société Royal Fish SA du Benin.
Authors: Dandjinou Maurice
Published: April 2021

Aquaculture, the cultivation of aquatic animal and plant organisms is a booming sector worldwide. The annual production of fish, crustaceans, molluscs and algae by aquaculture is estimated at 47% in 2006 according to the FAO, 2009. It is today the animal production showing the strongest growth (+ 8.7% per year since 1970 excluding China). Due to the depletion of wild stocks and the establishment of international fishing quotas, aquaculture must develop further to meet the growing global demand for fish and other aquatic organisms. In Benin, the fishing sector remains one of the poor relatives of the economy (2% of GDP - Proinvest 2002Agro-ind 2002) and fishermen (around 50,000) and fish wholesalers (around 20,000) mostly women are among the most deprived sections of the country. The fish production of water bodies continues to decrease despite the intensification of fishing (117 fishermen per km² against 9 in the sub-region: Source MAEP - State of play on Fishing) and the fish needs of the population continues to grow, hence the constant and massive importation of frozen fish by very powerful private companies. Large fish species (mostly catfish) are overexploited and have nowadays become very rare in the various fresh and brackish water fisheries of the country. As part of the diversification of the livelihoods of fishermen in order to sustainably reduce the pressure exerted on the water bodies, the current Ministry of Agriculture, Fisheries and Livestock has provided in its program of activities to pay particular attention to the promotion of aquaculture production and the repopulation of overexploited water bodies in Benin. The company Royal Fish Benin SA, by choosing to first develop the culture of African catfish - Clarias gariepinus - is part of this dynamic encouraged by the State of Benin which aims to reduce poverty in Benin. Royal Fish Benin is a Beninese public limited company specializing in the production, breeding, sale of African catfish Clarias gariepinus in different forms: fry, fresh table fish, smoked fish etc. It also ensures the sale of high-performance, quality food at the best cost. Finally, it offers training courses for local actors and producers. Royal Fish Benin has a production capacity of around 220 tonnes of table fish and over 1,000,000 fingerlings. This innovative project began on April 21, 2008 and saw the first sales of table fish in September 2008. Today the results obtained allow us to conclude that the project exceeded its expectations in terms of production and distribution. However, it is still too early to comment on the economic viability of the company.
Wastewater-fed aquaculture systems in Ho Chi Minh city, Vietnam: status and trends.
Authors: Huynh Pham Viet Huy
Published: April 2021

There are currently eight types of wastewater-fed aquaculture (WFA) systems in Ho Chi Minh City: seed production, fish-livestock, fish-water mimosa, fish-lotus, rice-fish, fish-only, water spinach, and fish-water spinach. Some utilize wastewater efficiently as a nutrient source, while some others have to control carefully the intake of wastewater. WFA has attracted farmers on their own initiative. Although it provides a living for a significant number of urban farmers and plays important roles in farmers' livelihoods, it is now under threat from the process of economic development of the city. The impacts of urbanization on former WFA sites in inner city zone of district 6 and district 8 where it is disappearing rapidly indicate what is likely to happen to current WFA sites in the city. Urbanization has also created livelihood uncertainties for farmers. The attraction of high prices of land and the impacts of urbanization projects are the main constraints, resulting in the decline in WFA areas. Pollution from uncontrolled and dispersed industrialization is another threat for WFA.
Shrimp farming with pen enclosures in south Brazil.
Authors: Suplicy Felipe
Published: April 2021

Native shrimp farming has been considered as an important alternative source of income for artisanal fishers and farmers in the Patos Lagoon estuary, southern Brazil. Considering the potential of estuarine areas for shrimp farming, the application of a low-cost structure to culture shrimp such as a pen is being proposed to complement capture fisheries and agriculture. From an economic standpoint, the use of pens has several advantages over a traditional pond-based culture system as land, water pumping and artificial aeration devices are not required. Relatively inexpensive materials may be employed for pen construction and running costs are minimized by the use of by-products from capture fishing to feed shrimps. These factors represent important points in lowering costs, which may turn small-scale shrimp farming into an economically feasible activity. Although this activity is in its initial stages of development, there is a strong tendency for the spread of this practice in coastal lagoons and estuaries in southern Brazil.
Seed production and grow-out of walking catfish (Clarias macrocephalus).
Authors: Pham Van Khanh
Published: April 2021

Ponds for catfish broodstock range in size from 500 to 1,000 m2, with a depth of 1-1.2 m. The stocking density of broodstock ranges from 0.2 to 0.3 kg m-2. The catfish are fed with fresh feeds such as snails, small prawns and trash fish. Farm-made feeds are also used for feeding. In the artificial spawning process, the ripe eggs are obtained by gently pressing the abdomen of the gravid females. The testis from the male has to be taken out from the fish to fertilize the eggs. The fertilized eggs are spread on the surface of a net in running water for incubation and hatching will occur in 22-24 hours. Nursing from fry to fingerlings is carried out in earthen ponds, which range in size from 500 to 1,000 m2 at a density of 200-500 fish m-2. Natural feed is cultured in the pond before stocking the fry for nursing. Supplementary feed, which is homemade, is also given during the nursing period. The fish reach 3.5-5.0 cm after 25-30 days of nursing. For grow-out ponds that range in size from 500 to 1,000 m2, stocking density is from 25 to 30 fish m-2. The fish are fed with trash fish, small prawns, snails, slaughterhouse by-products and commercial feed pellets. Fish reach marketable size of 350-400 g, or above, after 7-8 months of culture.
Research on combined cage-in-pond culture systems for South-East Asia.
Authors: Diana James
Published: April 2021

Submerging a cage within a pond and intensively feeding fish in the cage is one method of using the waste products from cage culture in semi-intensive pond culture. Using hybrid walking catfish, Clarias macrocephalus x C. gariepinus, in cages and Nile tilapia, Oreochromis niloticus, at large in ponds, treatments of one or two cages per pond produced better results than higher stocking densities. These treatments resulted in net fish yields as high as 56 tonnes ha-1 yr-1, and the most efficient system in terms of nutrient retention was using one cage per pond. The systems with one cage per pond delivered 3.7 kg of nitrogen (N) and 1.0 kg of phosphorus (P) ha-1 d-1, and retained 48% of the N added in fish, whereas two cages resulted in 34% N retention. For P, the results were 61 and 42% retained in fish, respectively. This aquaculture system resulted in some reduction in nutrient enrichment of ponds compared to feeding alone. A second series of experiments conducted using large Nile tilapia in cages, with small Nile tilapia in the pond, showed the best results when cages were stocked at 50 fish m-3 and the pond at 1.4 fish m-3. Survival was 98.8% for caged tilapia, which grew from 120 to 456 g in 90 days, with a net annual yield of 18 tonnes ha-1. Open-pond tilapia grew from 16 to 124 g with 92% survival and a net annual yield of 6.2 tonnes ha-1. The daily waste loading rate was approximately 1.7 kg of N and 0.37 kg of P ha-1, lower than the optimal fertilization rate proposed by CRSP experiments of 4 kg of N and 1 kg of P. Caged and pond fish accounted for about 50% of the N applied to the pond and about 60% of the P. The dynamics of oxygen, ammonium and plankton were evaluated against total loading rates for all culture combinations. Oxygen levels declined dramatically (about 75-100%) in all loading rates of ponds and never reached levels approaching zero decline in oxygen. N increased with increased loading density of fish and a level of zero change in ammonium would occur at a loading rate of about 0.8 kg m-3. Plankton dynamics showed similar results, and a fish loading rate with zero change in chlorophyll a should occur at a loading rate of about 0.3 kg m-3. These results indicate that it may be possible to reduce N and plankton contents in effluent water, but doing so would require loading rates that are not economically feasible.