Humpback whales (Megaptera novaeangliae) are well known to form closed lings of bubbles to encircle and concentrate prey for more efficient feeding - both alone and in cooperative groups. Similar ...behavior has been documented in Bryde's whales (Balaenoptera brydei), but the extent to which bubbles are used for prey manipulation is less understood for other rorqual species, including blue (Balaenoptera mussculus), fin (Balaenoptera physalus), and minke (Balaenoptera acutorostrata) whales. While not quantitatively analyzed, the qualitative evidence of regular and perhaps exclusive left-lateral lunge-feeding (LLF) in combination with bubbles contrasts with findings of previous studies that showed a strong preference for RLL feeding in fin whales.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
As halide perovskite materials have emerged at the forefront of optoelectronics development, there is an ongoing need to understand their underlying physics and control their emergent properties. ...Electrochemistry shows promise to both access fundamental parameters of perovskites and to enhance their performance through doping. However, halide perovskites pose a significant challenge to solution-based electrochemistry, as both aqueous solutions and organic solvents are often destructive to thin films of these materials. This work provides a perspective of recent approaches to electrochemical measurements and modifications of halide perovskites with a specific focus on stability and doping. We also report the electrochemistry of methylammonium lead iodide (MAPbI3) thin films relevant for solar applications with a solvent toolkit based on hydrofluoroethers. Both oxidation and reduction peaks are revealed from electrochemical characterization exhibiting the characteristic HOMO/LUMO levels and additional features. This electrochemical driving is found to have little impact on the photoluminescence or underlying morphology of the thin films. Finally, electrochemical lithium salt doping with this solvent toolkit enhanced the conductivity of a thin film device by nearly two orders of magnitude, demonstrating the utility of this approach for optoelectronic applications.
Display omitted
•Brief review of the electrochemistry of perovskites, emphasizing stability and doping.•Results shown with a hydrofluoroether solvent toolkit, a nondestructive electrolyte.•Hydrofluoroether electrochemistry revealed MAPbI3 oxidation and reduction peaks.•Photoluminescence and morphology were preserved in hydrofluoroether electrolyte.•Hydrofluoroether electrochemical doping increased conductivity nearly 100-fold.
Efficient knowledge extraction from Big Data is quite a challenging topic. Recognizing relevant concepts from unannotated data while considering both context and domain knowledge is critical to ...implementing successful knowledge extraction. In this research, we provide a novel platform we call Active Learning Integrated with Knowledge Extraction (ALIKE) that overcomes the challenges of context awareness and concept extraction, which have impeded knowledge extraction in Big Data. We propose a method to extract related concepts from unorganized data with different contexts using multiple agents, synergy, reinforcement learning, and active learning. We test ALIKE on the datasets of the COVID-19 Open Research Dataset Challenge. The experiment result suggests that the ALIKE platform can more efficiently distinguish inherent concepts from different papers than a non-agent-based method (without active learning) and that our proposed approach has a better chance to address the challenges of knowledge extraction with heterogeneous datasets. Moreover, the techniques used in ALIKE are transferable across any domain with multidisciplinary activity.
Conducting marine mammal research can raise several important ethical issues. For example, the continuation of whaling for commercial purposes despite the international moratorium provides ...opportunities for scientists to obtain data and tissue samples. In 2021 we analysed 35 peer-reviewed papers reporting research based on collaborations with Icelandic whalers. Results highlighted little consideration or understanding of the legal and ethical issues associated with the deliberate killing of whales amongst those researchers, funding bodies, universities and journals involved. Ethical statements were rarely provided. Those that were written were incomplete. Whilst research using whaling data may seem acceptable to some, it often becomes hard to justify when subject to scrutiny by the media and the public. Thus, there is a particular danger of reputational harm for early career researchers who may become unwittingly involved in such activities. Here we also consider the broader variety of ethical issues raised by non-lethal research (both historical and recent) on marine mammals including tagging and biopsy. We discuss instances where study animals were harmed or even killed and where the public mistook tags for harpoons. Without clear guidelines, reviewers and journal editors are put in an impossible position when considering whether to reject papers on ethical grounds. We propose that for such studies, universities, funders, journals, and permit issuers must require ethical assessments and that journals more effectively implement their existing policies on publishing ethical statements. The professional marine mammal societies need to work together to produce modern ethical guidance. Such guidance should require transparency in the provenance of data and samples while including advice on law, welfare issues, involvement of local scientists, and offshoring. Furthermore, it should require appraisal of and justification for the absolute necessity of invasive procedures. As is already the case in biomedical disciplines, ethical statements should be required in marine mammal science.
As opposed to inorganic counterparts, organic quantum dots often exhibit lower fluorescence efficiencies and are complex to synthesize. Here we develop nitrogen‐doped (N‐GQDs) and nitrogen–sulfur ...codoped (NS‐GQDs) graphene quantum dots exhibiting high‐yield visible and near‐IR emission that are synthesized via a single‐step microwave‐assisted hydrothermal technique with a single glucosamine‐HCl starting material (thiourea precursor used for NS‐GQDs). As‐synthesized N‐GQDs and NS‐GQDs are well‐dispersed (average sizes of 5.50 and 3.90 nm) with high crystallinity and pronounced G‐band. Formed by the bottom‐up assembly of glucosamine, they contain amine linkage and a variety of oxygen‐containing functional groups assessed by Fourier‐transform infrared spectroscopy with ≈2% sulfur for NS‐GQDs. The synthetic procedure allows varying their size and the bandgap. Unlike other graphene‐based quantum dots, these GQDs exhibit bright, stable fluorescence both in the visible and near‐IR with high quantum yields of up to 60%. Excitation‐dependent visible fluorescence is attributed to size‐dependent bandgaps, with near‐IR emission potentially arising from the emissive defect states/their arrangements. Advantageous properties of these GQDs are utilized to develop exciton recombination layer for organic light‐emitting devices exhibiting both photoluminescence and electroluminescence in the visible. Produced by ecofriendly one‐step scalable synthesis brightly‐emissive N‐GQDs and NS‐GQDs become a promising material for novel organic optoelectronics.
Nitrogen‐doped and nitrogen–sulfur codoped graphene quantum dots are synthesized by a one‐step scalable microwave‐assisted hydrothermal method. The quantum dots show excitation‐dependent bright and stable fluorescence in the visible and NIR regime with quantum yields up to 60%. These quantum dots are further used to fabricate light‐emitting diodes that exhibit electroluminescence with high current density and moderate turn‐on voltage.
To describe chorea/ballism triggered by a hyperglycemic event.
We used the electronic records system at Mayo Clinic–Rochester to identify patients diagnosed with chorea or ballism from January 1st, ...2000 through December 31st, 2014. Each record was reviewed to confirm chorea/ballism. From these cases we selected those that developed chorea/ballism within a month after a hyperglycemic episode (blood glucose >300 mg/dL). Clinical, laboratory, and imaging findings were analyzed.
Of the 596 chorea cases, we identified 7 patients (5 women) whose chorea was preceded by a hyperglycemic episode (range 3–30 days) during 15 years of surveillance, including new-onset diabetes in four cases. Median age was 80 years (range, 53–86). The chorea/ballism was unilateral in 6/7 cases and half of these unilateral cases had contralateral putamen T1-hyperintensity on brain MRI. After glucose correction, the chorea resolved within one week without recurrence in only one case. Among the 6 cases with persistent chorea, it was controlled with dopamine blocking/depleting medications.
Chorea triggered by hyperglycemia is a rare complication of diabetes, with only seven cases identified at our tertiary medical center during 15 years of surveillance. This comprised about 1% of all chorea cases at our center during this time. Hyperglycemic chorea primarily developed in later life, with new-onset diabetes in the majority (4/7). Although MRI putamen T1-hyperintensity is reportedly typical, it was only seen in 3/6 cases. This MRI appearance may be mistaken for a hemorrhagic stroke, given the usual unilateral presentation. The chorea was controlled with dopamine blocking/depleting medications.
•Hyperglycemia causes about 1% of acquired chorea, which is usually persistent.•Chorea developing within 1 month of an episode of hyperglycemia is suggestive.•Putamen T1 hyperintensity occurs in half and is often misdiagnosed as hemorrhage.•Advanced age and newly diagnosed type 2 diabetes are commonly seen.•Most cases are unilateral and responsive to dopamine blocking or depleting agents.
For cetaceans to be sentinels of environmental change, reliable methods to assess overall health and physiological state are required. Blubber lipid content of remotely darted biopsies has been used ...to approximate energy stores and overall health. However, studies on beluga (
Delphinapterus leucas
), fin (
Balaenoptera physalus
) and killer whales (
Orcinus orca
) found a sampling effect (lipid-loss) biasing blubber biopsy lipid content. To determine if this applies to all cetaceans, we conducted a literature review, comparing the lipid content of outer blubber from biopsy (darted) and stranding (excised) samples for 27 species. For 16 species of five taxa (Balaenidae, Balaenopteridae, Delphinidae, Physeteridae and Ziphiidae), independent observations (
n
= 1346) of both biopsies and strandings were available. With taxon as a factor, a beta regression model (pseudo-
R
2
= 0.638) determined that the mean lipid content of biopsies is 11.1 ± 1.9% lower than that of strandings. Post hoc Šidák tests confirmed that the difference among sampling methods was statistically significant (
α
= 0.05) for all taxa (
p
< 0.001). This is a universal problem, likely due to tissue disruption associated with the force of the biopsy dart resulting in lipid loss and confirms that biopsy lipid content estimates are unreliable indicators of health or body condition. Our results have unexplored implications for the quantification of blubber biopsy lipid fractions for fatty acid or contaminant analyses, for example. There is a welfare and conservation imperative to develop alternative markers of overall health and physiological state from biopsies. In this regard, emerging technologies such as ‘omics analyses look particularly promising.
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