scikit-image: image processing in Python van der Walt, Stéfan; Schönberger, Johannes L; Nunez-Iglesias, Juan ...
PeerJ (San Francisco, CA),
06/2014, Letnik:
2
Journal Article
Recenzirano
Odprti dostop
scikit-image is an image processing library that implements algorithms and utilities for use in research, education and industry applications. It is released under the liberal Modified BSD open ...source license, provides a well-documented API in the Python programming language, and is developed by an active, international team of collaborators. In this paper we highlight the advantages of open source to achieve the goals of the scikit-image library, and we showcase several real-world image processing applications that use scikit-image. More information can be found on the project homepage, http://scikit-image.org.
Most extreme precipitation events that occur along the North American west coast are associated with winter atmospheric river (AR) events. Global climate models have sufficient resolution to simulate ...synoptic features associated with AR events, such as high values of vertically integrated water vapor transport (IVT) approaching the coast. From phase 5 of the Coupled Model Intercomparison Project (CMIP5), 10 simulations are used to identify changes in ARs impacting the west coast of North America between historical (1970–99) and end-of-century (2070–99) runs, using representative concentration pathway (RCP) 8.5. The most extreme ARs are identified in both time periods by the 99th percentile of IVT days along a north–south transect offshore of the coast. Integrated water vapor (IWV) and IVT are predicted to increase, while lower-tropospheric winds change little. Winter mean precipitation along the west coast increases by 11%–18% from 4% to 6% (°C)−1, while precipitation on extreme IVT days increases by 15%–39% from 5% to 19% (°C)−1. The frequency of IVT days above the historical 99th percentile threshold increases as much as 290% by the end of this century.
The interaction of dislocations with Guinier–Preston (GP) zones is a process that contributes to the yield strength of many underaged precipitate-strengthened alloys. Here we use atomistic modeling ...to investigate this process in an Al–Cu alloy using a newly developed interatomic potential. The study focuses on edge dislocation interactions in the athermal limit. The critical shear stress and the mechanism by which dislocations overcome GP zones is found to vary significantly depending upon GP zone size, orientation and offset from the dislocation glide plane. Dislocation cutting, looping, leading partial cutting with trailing partial looping, diffusionless climb and defect nucleation at the dislocation–GP zone contact point are all observed. In the majority of cases dislocation looping is the controlling mechanism, challenging the applicability of traditional continuum dislocation cutting models to the underaged Al–Cu system at 0K.
Crack-tip behaviour in metals is among the most basic problems in mechanics of materials. Yet, long-standing experimental evidence suggests that crack-tip twinning in face-centred-cubic (f.c.c.) ...metals is highly dependent on the material, temperature and loading rate, and previous simulations and models predict twinning in aluminium, where it has never been observed. Here, this discrepancy between theory and experiment is resolved through a new model guided and validated by extensive multiscale simulations. Both the analytic model and simulations reveal a transition from crack-tip twinning at short times to full dislocation formation at long times. Applied to a host of f.c.c. metals, the model agrees with experimental trends as it predicts large differences in the thermal activation needed for full dislocation emission to dominate. More broadly, this work demonstrates the necessity of multiscale modelling and attention to rate dependence for accurate description of material behaviour and computationally guided material design.
The asteroid lightcurve database Warner, Brian D.; Harris, Alan W.; Pravec, Petr
Icarus (New York, N.Y. 1962),
07/2009, Letnik:
202, Številka:
1
Journal Article
Recenzirano
The compilation of a central database for asteroid lightcurve data, i.e., rotation rate and amplitude along with ancillary information such as diameter and albedo (known or estimated), taxonomic ...class, etc., has been important to statistical studies for several decades. Having such a compilation saves the researcher hours of effort combing through any number of journals, some obvious and some not, to check on prior research. Harris has been compiling such data in the Asteroid Lightcurve Database (LCDB) for more than 25 years with Warner and Pravec assisting the past several years. The main data included in the LCDB are lightcurve rotation periods and amplitudes, color indices, H–G parameters, diameters (actual or derived), basic binary asteroid parameters, and spin axis and shape models. As time permits we are reviewing existing entries to enter data not previously recorded (e.g., phase angle data). As of 2008 December, data for 3741 asteroids based on more than 10650 separate detail records derived from entries in various journals were included in the LCDB. Of those 3741 asteroids, approximately 3100 have data of sufficient quality for statistical analysis, including 7 that have “dual citizenship” – meaning that they have (or had) asteroid designations as well comet designations. Here we present a discussion of the nature of LCDB data, i.e., which values are actually measured and which are derived. For derived data, we give our justification for specific values. We also present some analysis based on the LCDB data, including new default albedo (pV) and phase slope parameter (G) values for the primary taxonomic classes and a review of the frequency–diameter distribution of all asteroids as well as some selected subsets. The most recent version of data used in this analysis is available for download from the Collaborative Asteroid Lightcurve Link (CALL) site at http://www.MinorPlanetObserver.com/astlc/default.htm. Other data sets, some only subsets of the full LCDB, are available in the Ephemeris of Minor Planets, The Planetary Data System, and the Minor Planet Center web site.
The ILCOR Basic Life Support Task Force and the international drowning research community considered it timely to undertake a scoping review of the literature to identify evidence relating to the ...initial resuscitation, hospital-based interventions and criteria for safe discharge related to drowning.
Medline, PreMedline, Embase, Cochrane Reviews and Cochrane CENTRAL were searched from 2000 to June 2020 to identify relevant literature. Titles and abstracts and if necessary full text were reviewed in duplicate. Studies were eligible for inclusion if they reported on the population (adults and children who are submerged in water), interventions (resuscitation in water/boats, airway management, oxygen administration, AED use, bystander CPR, ventilation strategies, ECMO, protocols for hospital discharge (I), comparator (standard care) and outcomes (O) survival, survival with a favourable neurological outcome, CPR quality, physiological end-points).
The database search yielded 3242 references (Medline 1104, Pre-Medline 202, Embase 1722, Cochrane reviews 12, Cochrane CENTRAL 202). After removal of duplicates 2377 papers were left for screening titles and abstracts. In total 65 unique papers were included. The evidence identified was from predominantly high-income countries and lacked consistency in the populations, interventions and outcomes reported. Clinical studies were exclusively observational in nature.
This scoping review found that there is very limited evidence from observational studies to inform evidence based clinical practice guidelines for drowning. The review highlights an urgent need for high quality research in drowning.
Eukaryotic replication initiation is highly regulated and dynamic. It begins with the Origin Recognition Complex (ORC) binding DNA sites called origins of replication. ORC, together with Cdc6 and ...Cdt1, mediate pre-Replicative Complex (pre-RC) assembly by loading a double hexamer of Mcm2-7: the core of the replicative helicase. Here, we use single-molecule imaging to directly visualize Saccharomyces cerevisiae pre-RC assembly and replisome firing in real time. We show that ORC can locate and stably bind origins within large tracts of non-origin DNA, and that Cdc6 drives ordered pre-RC assembly. We further show that the dynamics of the ORC-Cdc6 interaction dictate Mcm2-7 loading specificity and that Mcm2-7 double hexamers form preferentially at a native origin sequence. Finally, we demonstrate that single Mcm2-7 hexamers propagate bidirectionally, monotonically, and processively as constituents of active replisomes.
•Pivotal steps of replication initiation are studied at the single-molecule level.•Cdc6 dictates the ordered and specific assembly of pre-RC components.•Initiation is tightly regulated, ensuring that sister forks fire simultaneously.•Replisome progression is processive and insensitive to DNA sequence composition.
Seaweed is an important food widely consumed in Asian countries. Seaweed has a diverse array of bioactive compounds, including dietary fiber, carbohydrate, protein, fatty acid, minerals and ...polyphenols, which contribute to the health benefits and commercial value of seaweed. Nevertheless, detailed information on polyphenol content in seaweeds is still limited. Therefore, the present work aimed to investigate the phenolic compounds present in eight seaweeds Chlorophyta (green),
sp.,
sp. and
sp.; Rhodophyta (red),
sp.,
sp. and
sp.; Ochrophyta (brown),
sp.,
sp., using liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS/MS). The total phenolic content (TPC), total flavonoid content (TFC) and total tannin content (TTC) were determined. The antioxidant potential of seaweed was assessed using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assay, a 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) free radical scavenging assay and a ferric reducing antioxidant power (FRAP) assay. Brown seaweed species showed the highest total polyphenol content, which correlated with the highest antioxidant potential. The LC-ESI-QTOF-MS/MS tentatively identified a total of 54 phenolic compounds present in the eight seaweeds. The largest number of phenolic compounds were present in
sp. followed by
sp. and
sp. Using high-performance liquid chromatography-photodiode array (HPLC-PDA) quantification, the most abundant phenolic compound was
-hydroxybenzoic acid, present in
sp. at 846.083 ± 0.02 μg/g fresh weight. The results obtained indicate the importance of seaweed as a promising source of polyphenols with antioxidant properties, consistent with the health potential of seaweed in food, pharmaceutical and nutraceutical applications.
In order for livestock industries to consistently produce high quality meat, there must be an understanding of the factors that cause quality to vary, as well as the contribution of genetics. A brief ...overview of meat tenderness is presented to understand how genotype and environment may interact to influence this trait. Essentially, meat tenderness is determined from the contribution of connective tissue, sarcomere length determined pre-rigor and rate of proteolysis during ageing, as well as contributions from intramuscular fat and post-mortem energy metabolism. The influence of mutations in myostatin, the
callipyge gene, the
Carwell or
rib eye muscle gene as well as the calpain system on meat tenderness is presented. Specific examples of interactions between the production or processing environment and genetics are presented for both sheep and cattle. The day-to-day variation in tenderness is evident across experiments and this variation needs to be controlled in order to consistently produce tender meat.
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