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BACKGROUND: In patients with out-of-hospital cardiac arrest, the effectiveness of drugs such as epinephrine is highly time-dependent. An intraosseous route of drug administration may enable more rapid drug administration than an intravenous route; however, its effect on clinical outcomes is uncertain. METHODS: We conducted a multicenter, open-label, randomized trial across 11 emergency medical systems in the United Kingdom that involved adults in cardiac arrest for whom vascular access for drug administration was needed. Patients were randomly assigned to receive treatment from paramedics by means of an intraosseous-first or intravenous-first vascular access strategy. The primary outcome was survival at 30 days. Key secondary outcomes included any return of spontaneous circulation and favorable neurologic function at hospital discharge (defined by a score of 3 or less on the modified Rankin scale, on which scores range from 0 to 6, with higher scores indicating greater disability). No adjustment for multiplicity was made. RESULTS: A total of 6082 patients were assigned to a trial group: 3040 to the intraosseous group and 3042 to the intravenous group. At 30 days, 137 of 3030 patients (4.5%) in the intraosseous group and 155 of 3034 (5.1%) in the intravenous group were alive (adjusted odds ratio, 0.94; 95% confidence interval [CI], 0.68 to 1.32; P = 0.74). At the time of hospital discharge, a favorable neurologic outcome was observed in 80 of 2994 patients (2.7%) in the intraosseous group and in 85 of 2986 (2.8%) in the intravenous group (adjusted odds ratio, 0.91; 95% CI, 0.57 to 1.47); a return of spontaneous circulation at any time occurred in 1092 of 3031 patients (36.0%) and in 1186 of 3035 patients (39.1%), respectively (adjusted odds ratio, 0.86; 95% CI, 0.76 to 0.97). During the trial, one adverse event, which occurred in the intraosseous group, was reported. CONCLUSIONS: Among adults with out-of-hospital cardiac arrest requiring drug therapy, the use of an intraosseous-first vascular access strategy did not result in higher 30-day survival than an intravenous-first strategy. (Funded by the National Institute for Health and Care Research; PARAMEDIC-3 ISRCTN Registry number, ISRCTN14223494.).
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The living coelacanth Latimeria (Sarcopterygii: Actinistia) is an iconic, so-called 'living fossil' within one of the most apparently morphologically conservative vertebrate groups. We describe a new, 3-D preserved coelacanth from the Late Devonian Gogo Formation in Western Australia. We assemble a comprehensive analysis of the group to assess the phylogeny, evolutionary rates, and morphological disparity of all coelacanths. We reveal a major shift in morphological disparity between Devonian and post-Devonian coelacanths. The newly described fossil fish fills a critical transitional stage in coelacanth disparity and evolution. Since the mid-Cretaceous, discrete character changes (representing major morphological innovations) have essentially ceased, while meristic and continuous characters have continued to evolve within coelacanths. Considering a range of putative environmental drivers, tectonic activity best explains variation in the rates of coelacanth evolution.
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Evolución Biológica , Peces , Fósiles , Filogenia , Animales , Peces/anatomía & histología , Peces/clasificación , Peces/genética , Australia OccidentalRESUMEN
Total parenteral nutrition (TPN) provides lifesaving nutritional support intravenously; however, it is associated with significant side effects. Given gut microbial alterations noted with TPN, we hypothesized that transferring fecal microbiota from healthy controls would restore gut-systemic signaling in TPN and mitigate injury. Using our novel ambulatory model (US Patent: US 63/136,165), 31 piglets were randomly allocated to enteral nutrition (EN), TPN only, TPN + antibiotics (TPN-A), or TPN + intraduodenal fecal microbiota transplant (TPN + FMT) for 14 days. Gut, liver, and serum were assessed through histology, biochemistry, and qPCR. Stool samples underwent 16 s rRNA sequencing. Permutational multivariate analysis of variance, Jaccard, and Bray-Curtis metrics were performed. Significant bilirubin elevation in TPN and TPN-A versus EN (P < 0.0001) was prevented with FMT. IFN-G, TNF-α, IL-ß, IL-8, and lipopolysaccharide (LPS) were significantly higher in TPN (P = 0.009, P = 0.001, P = 0.043, P = 0.011, P < 0.0001), with preservation upon FMT. Significant gut atrophy by villous-to-crypt ratio in TPN (P < 0.0001) and TPN-A (P = 0.0001) versus EN was prevented by FMT (P = 0.426 vs. EN). Microbiota profiles using principal coordinate analysis demonstrated significant FMT and EN overlap, with the largest separation in TPN-A followed by TPN, driven primarily by Firmicutes and Fusobacteria. TPN-altered gut barrier was preserved upon FMT; upregulated cholesterol 7 α-hydroxylase and bile salt export pump in TPN and TPN-A and downregulated fibroblast growth factor receptor 4, EGF, farnesoid X receptor, and Takeda G Protein-coupled Receptor 5 (TGR5) versus EN was prevented by FMT. This study provides novel evidence of prevention of gut atrophy, liver injury, and microbial dysbiosis with intraduodenal FMT, challenging current paradigms into TPN injury mechanisms and underscores the importance of gut microbes as prime targets for therapeutics and drug discovery.NEW & NOTEWORTHY Intraduodenal fecal microbiota transplantation presents a novel strategy to mitigate complications associated with total parenteral nutrition (TPN), highlighting gut microbiota as a prime target for therapeutic and diagnostic approaches. These results from a highly translatable model provide hope for TPN side effect mitigation for thousands of chronically TPN-dependent patients.
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Colestasis , Trasplante de Microbiota Fecal , Microbioma Gastrointestinal , Nutrición Parenteral Total , Animales , Trasplante de Microbiota Fecal/métodos , Porcinos , Colestasis/terapia , Colestasis/microbiología , Nutrición Parenteral Total/métodos , Atrofia , Modelos Animales de Enfermedad , Hígado/patología , Hígado/metabolismoRESUMEN
Orb-weaver spiders produce upwards of seven different types of silk, each with unique material properties. We focus on the adhesive within orb-weaving spider webs, aggregate glue silk. These droplets are composed of three main components: water, glycoproteins, and a wide range of low molecular mass compounds (LMMCs). These LMMCs are known to play a crucial role in maintaining the material properties of the glycoproteins, aid in water absorption from the environment, and increase surface adhesion. Orb-weavers within the Cyrtarachninae subfamily are moth specialists and have evolved glue droplets with novel material properties. This study investigated the biochemical composition and diversity of the LMMCs present in the aggregate glue of eight moth-specialist species and compared them with five generalist orb-weavers using nuclear magnetic resonance (NMR) spectroscopy. We hypothesized that the novel drying ability of moth-specialist glue was accompanied by novel LMMCs and lower overall percentages by silk weight of LMMCs. We measured no difference in LMMC weight by the type of prey specialization, but observed novel compositions in the glue of all eight moth-catching species. Further, we quantified the presence of a previously reported but unidentified compound that appears in the glue of all moth specialists. These silks can provide insight into the functions of bioadhesives and inform our own synthetic adhesives.
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This study assessed the multifaceted relations between measures of workload, psychological state, and recovery throughout an entire soccer season in female collegiate soccer athletes (19.8±1.2 yrs, 132±12.3 lbs, 63±3.2 in). A prospective longitudinal study was utilized to measure workload (GPS training load, Rate of Perceived Exertion (RPE), psychological state (mental stress, mental fatigue, and mood), and recovery (sleep duration, sleep quality, and soreness), during 90 observations (59 training sessions and 21 games). Separate linear-mixed effect models were used to assess outcomes of RPE, soreness, and sleep duration. A linear mixed-effects model explained 59% of the variance in RPE following each session. Specifically, each standard deviation increase in GPS load and mental stress in the morning prior to training increased RPE by 1.46 (SE=0.08) and 0.29 (SE=0.07), respectively, following that day's training. Furthermore, a significant interaction was found between several predictor variables and chronological day in the season while predicting RPE. Specifically, for each standard deviation increase in GPS load, RPE went up by 0.0055 per day during the season suggesting that load had a higher impact on RPE as the season progressed. In contrast, the interaction of day by mental stress, sleep duration, and soreness continued to be stronger as the season progressed. Each linear mixed-effect model predicted a larger amount of variance when accounting for individual variations in the random effects.
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Fatiga Mental , Mialgia , Esfuerzo Físico , Fútbol , Estrés Psicológico , Carga de Trabajo , Humanos , Fútbol/psicología , Fútbol/fisiología , Femenino , Adulto Joven , Estudios Prospectivos , Carga de Trabajo/psicología , Esfuerzo Físico/fisiología , Estudios Longitudinales , Mialgia/psicología , Acondicionamiento Físico Humano/psicología , Acondicionamiento Físico Humano/fisiología , Afecto/fisiología , Adolescente , Calidad del Sueño , Sistemas de Información GeográficaRESUMEN
Utilising a flexible intracortical microprobe to record/stimulate neurons minimises the incompatibility between the implanted microprobe and the brain, reducing tissue damage due to the brain micromotion. Applying bio-dissolvable coating materials temporarily makes a flexible microprobe stiff to tolerate the penetration force during insertion. However, the inability to adjust the dissolving time after the microprobe contact with the cerebrospinal fluid may lead to inaccuracy in the microprobe positioning. Furthermore, since the dissolving process is irreversible, any subsequent positioning error cannot be corrected by re-stiffening the microprobe. The purpose of this study is to propose an intracortical microprobe that incorporates two compressible structures to make the microprobe both adaptive to the brain during operation and stiff during insertion. Applying a compressive force by an inserter compresses the two compressible structures completely, resulting in increasing the equivalent elastic modulus. Thus, instant switching between stiff and soft modes can be accomplished as many times as necessary to ensure high-accuracy positioning while causing minimal tissue damage. The equivalent elastic modulus of the microprobe during operation is ≈ 23 kPa, which is ≈ 42% less than the existing counterpart, resulting in ≈ 46% less maximum strain generated on the surrounding tissue under brain longitudinal motion. The self-stiffening microprobe and surrounding neural tissue are simulated during insertion and operation to confirm the efficiency of the design. Two-photon polymerisation technology is utilised to 3D print the proposed microprobe, which is experimentally validated and inserted into a lamb's brain without buckling.
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Encéfalo , Fenómenos Mecánicos , Animales , Ovinos , Microelectrodos , Módulo de Elasticidad , Presión , Encéfalo/fisiologíaRESUMEN
For over 70 million years, during the Paleozoic, the placoderms (Greek for 'plated skin'), an extinct group of armoured fishes, were the most abundant and diverse vertebrates on our planet. Some of the first placoderm fossils discovered - such as Bothriolepis with its bone-covered pectoral fins - seemed so bizarre that they were thought to represent turtles or ancient beetles. All placoderms bear thick overlapping dermal plates around the head (called the 'head shield') and an area of the body covered in similar overlapping plates enveloping the pectoral to anal region (called the 'trunk-shield'). Placoderm fossils (Figure 1) are known from every continent on Earth ranging from the early Silurian (â¼438 million years ago) to the end Devonian (â¼359 million years ago) when they became extinct.
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Escarabajos , Ursidae , Animales , Humanos , Fósiles , Planeta Tierra , Extinción Psicológica , PielRESUMEN
Aims: The PARAMEDIC-3 trial evaluates the clinical and cost-effectiveness of an intraosseous first strategy, compared with an intravenous first strategy, for drug administration in adults who have sustained an out-of-hospital cardiac arrest. Methods: PARAMEDIC-3 is a pragmatic, allocation concealed, open-label, multi-centre, superiority randomised controlled trial. It will recruit 15,000 patients across English and Welsh ambulance services. Adults who have sustained an out-of-hospital cardiac arrest are individually randomised to an intraosseous access first strategy or intravenous access first strategy in a 1:1 ratio through an opaque, sealed envelope system. The randomised allocation determines the route used for the first two attempts at vascular access. Participants are initially enrolled under a deferred consent model.The primary clinical-effectiveness outcome is survival at 30-days. Secondary outcomes include return of spontaneous circulation, neurological functional outcome, and health-related quality of life. Participants are followed-up to six-months following cardiac arrest. The primary health economic outcome is incremental cost per quality-adjusted life year gained. Conclusion: The PARAMEDIC-3 trial will provide key information on the clinical and cost-effectiveness of drug route in out-of-hospital cardiac arrest.Trial registration: ISRCTN14223494, registered 16/08/2021, prospectively registered.
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A crucial step for validating the utility of an immersive virtual reality (iVR) buffet to study eating behavior is to determine whether variations in food characteristics such as portion size (PS) are relevant predictors of food selection in an iVR buffet. We tested whether manipulating PS in an iVR buffet affects the weight of food selected, and whether this response to PS is similar to participants' measured intake when PS varies at laboratory meals. In a randomized crossover design, 91 adults (18-71 y; 64 females; BMI = 25.3 ± 5.7) used their iVR remote to select lunch and dinner portions from an iVR buffet before consuming a standardized lab meal at two visits separated by one week. The PS in the iVR buffet and lab meals varied between a standard PS and a large PS. This design enabled comparisons of PS effects between iVR and lab settings, despite the scale difference in food weight between the environments. Portion size significantly affected food selection and food intake (p < 0.001). Subjects selected an additional 350 g in iVR and consumed an additional 154 g of food in the lab meals when offered the large portion compared to the small portion. The effect of PS showed a similar percentage increase in iVR (36.5%) and lab meals (39.2%). There was no significant difference in the effect of PS between iVR and lab meals after accounting for scale differences in food weight between the environments. The response to PS was not influenced by subject characteristics such as body mass index, sex, or age. These results demonstrate the utility of iVR for replicating real-world eating behaviors and enhancing our understanding of the intricate dynamics of food-related behaviors in a variety of contexts.
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PURPOSE: To determine the incidence of tympanostomy tube (T-tube) insertion in children who required probing and intubation for congenital nasolacrimal duct obstruction (CNLDO) at a single academic institution and to analyze success rates. METHODS: The medical records of 92 patients who underwent nasolacrimal probing and intubation for CNLDO over a 9-year period were reviewed retrospectively. A preoperative questionnaire was given to the patient's guardian concerning laterality of CNLDO, history of otitis media (OM) antibiotic therapy, history of T-tube placement and number placed. At least 12 months following the initial nasolacrimal duct P&I, a second questionnaire was administered regarding resolution of CNLDO symptoms, additional measures taken to relieve postoperative symptoms if present, and any further history regarding OM episodes or T-tube insertion. RESULTS: Of the 92 children with CNLDO, 37 (40%) required T-tubes either prior to or following nasolacrimal duct probing and intubation, a rate higher than in the general population (P < 0.00001). 21 (56%) of CNLDO probing and intubation patients who required T-tubes required at least two sets, at different times, to relieve OM symptoms. Six of 37 patients (16%) with a history of T-tube placement and 1 of 55 (2%) with no history of T-tube placement had persistent epiphora after nasolacrimal probing and intubation (relative risk, 8.92; P = 0.0388). CONCLUSIONS: In our study cohort, pediatric patients with CNLDO who required nasolacrimal probing and intubation were at higher risk of needing T-tubes for chronic OM than the general population, and those needing T-tubes were at increased risk of residual epiphora.
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Dacriocistorrinostomía , Obstrucción del Conducto Lagrimal , Conducto Nasolagrimal , Niño , Humanos , Lactante , Obstrucción del Conducto Lagrimal/terapia , Obstrucción del Conducto Lagrimal/congénito , Conducto Nasolagrimal/cirugía , Incidencia , Estudios Retrospectivos , Ventilación del Oído Medio , Intubación/métodos , Intubación Intratraqueal , Resultado del TratamientoRESUMEN
Introduction: The modern eating environment has been implicated as a driving force of the obesity epidemic. Mixed reality applications may improve traditional methodological assessments of eating behavior by improving the ecological validity of the laboratory setting. Methods: Research experts evaluated the utility and ecological validity of a mixed reality application that allowed immersion within virtual environments through utilizing the passthrough cameras of the head mounted display to view and interact with real foods. An initial evaluation was conducted that involved three virtual environments: a traditional laboratory booth, a non-textured restaurant, and a full-textured restaurant. The feedback from the initial evaluation was used to create a new virtual restaurant environment and a subsequent evaluation was conducted. Results: Nearly all research experts suggested adding social cues such as people and background noise to create a more authentic and ecologically valid experience. The experts scored the new virtual restaurant environment to be more acceptable than eating or conducting research in a sensory booth but scored lower when compared to conducting research in a real-world restaurant setting. Discussion: The results of this evaluation suggest that mixed reality applications may be a new methodology to assess environmental influences of eating behavior and may be a promising direction for eating behavior and sensory science research.
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British crossbred steers (nâ =â 3,072; initial body weight [BW]â =â 358â ±â 37 kg) were used to evaluate the effects of chromium propionate supplementation to yearling steers in a commercial feedyard on growth performance, carcass characteristics, and health. Steers were blocked by initial BW; pens were assigned randomly to one of two dietary treatments within block. Treatments, replicated in 15 pens per treatment with 75 to 135 heads per pen, included 1) control, 0 mg supplemental Cr/kg dietary dry matter (DM) (CTL); 2) 0.50 mg supplemental Cr/kg diet DM (chromium propionate; KemTRACE Chromium 0.4%, Kemin Industries, Des Moines, IA) (chromium propionate, CR). Final BW (638 vs. 641 kg), average daily gain (1.81 vs. 1.82 kg), DM intake (11.02 vs. 11.02 kg), and gain efficiency (0.164 vs. 0.165) did not differ between CTL and CR, respectively (Pâ ≥â 0.75). No differences among treatments for hot carcass weight (407 vs. 408 kg, CTL and CR, respectively), dressing percentage, longissimus muscle area, or yield grade were observed (Pâ ≥â 0.15). Twelfth-rib fat thickness tended (Pâ =â 0.10) to be greater for CR vs. CTL (1.55 vs. 1.29 cm, respectively). A trend (Pâ =â 0.10) for marbling score to be higher for CR vs. CTL was detected (452 vs. 440, respectively). Distribution of quality grade was similar between CR and CTL; 1.52% of carcasses graded prime (Pâ =â 0.68), and 87.2% of carcasses graded choice (Pâ =â 0.68). Respiratory morbidity was low (1.93%) and not different among treatments (Pâ =â 0.20); likewise, there was no difference in respiratory treatment rates between treatments (Pâ ≥â 0.18). Supplementing Cr to high-performing yearling steers did not alter growth performance, carcass characteristics, or health outcomes.
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Jensen et al. (1) question evidence presented of a chambered heart within placoderms, citing its small size and apparently ventral atrium. However, they fail to note the belly-up orientation of the placoderm within one nodule, and the variability of heart morphology within extant taxa. Thus, we remain confident in our interpretation of the mineralized organ as the heart.
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Evolución Biológica , Fósiles , Corazón , Preservación Biológica , Animales , Peces/fisiologíaRESUMEN
BACKGROUND: The clinical narrative in electronic health records (EHRs) carries valuable information for predictive analytics; however, its free-text form is difficult to mine and analyze for clinical decision support (CDS). Large-scale clinical natural language processing (NLP) pipelines have focused on data warehouse applications for retrospective research efforts. There remains a paucity of evidence for implementing NLP pipelines at the bedside for health care delivery. OBJECTIVE: We aimed to detail a hospital-wide, operational pipeline to implement a real-time NLP-driven CDS tool and describe a protocol for an implementation framework with a user-centered design of the CDS tool. METHODS: The pipeline integrated a previously trained open-source convolutional neural network model for screening opioid misuse that leveraged EHR notes mapped to standardized medical vocabularies in the Unified Medical Language System. A sample of 100 adult encounters were reviewed by a physician informaticist for silent testing of the deep learning algorithm before deployment. An end user interview survey was developed to examine the user acceptability of a best practice alert (BPA) to provide the screening results with recommendations. The planned implementation also included a human-centered design with user feedback on the BPA, an implementation framework with cost-effectiveness, and a noninferiority patient outcome analysis plan. RESULTS: The pipeline was a reproducible workflow with a shared pseudocode for a cloud service to ingest, process, and store clinical notes as Health Level 7 messages from a major EHR vendor in an elastic cloud computing environment. Feature engineering of the notes used an open-source NLP engine, and the features were fed into the deep learning algorithm, with the results returned as a BPA in the EHR. On-site silent testing of the deep learning algorithm demonstrated a sensitivity of 93% (95% CI 66%-99%) and specificity of 92% (95% CI 84%-96%), similar to published validation studies. Before deployment, approvals were received across hospital committees for inpatient operations. Five interviews were conducted; they informed the development of an educational flyer and further modified the BPA to exclude certain patients and allow the refusal of recommendations. The longest delay in pipeline development was because of cybersecurity approvals, especially because of the exchange of protected health information between the Microsoft (Microsoft Corp) and Epic (Epic Systems Corp) cloud vendors. In silent testing, the resultant pipeline provided a BPA to the bedside within minutes of a provider entering a note in the EHR. CONCLUSIONS: The components of the real-time NLP pipeline were detailed with open-source tools and pseudocode for other health systems to benchmark. The deployment of medical artificial intelligence systems in routine clinical care presents an important yet unfulfilled opportunity, and our protocol aimed to close the gap in the implementation of artificial intelligence-driven CDS. TRIAL REGISTRATION: ClinicalTrials.gov NCT05745480; https://www.clinicaltrials.gov/ct2/show/NCT05745480.
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Nearly all fish have flexible bodies that bend as a result of internal muscular forces and external fluid forces that are dynamically coupled with the mechanical properties of the body. Swimming is therefore strongly influenced by the body's flexibility, yet we do not know how fish species vary in their flexibility and in their ability to modulate flexibility with muscle activity. A more fundamental problem is our lack of knowledge about how any of these differences in flexibility translate into swimming performance. Thus, flexibility represents a hidden axis of diversity among fishes that may have substantial impacts on swimming performance. Although engineers have made substantial progress in understanding these fluid-structure interactions using physical and computational models, the last biological review of these interactions and how they give rise to fish swimming was carried out more than 20 years ago. In this Review, we summarize work on passive and active body mechanics in fish, physical models of fish and bioinspired robots. We also revisit some of the first studies to explore flexural stiffness and discuss their relevance in the context of more recent work. Finally, we pose questions and suggest future directions that may help reveal important links between flexibility and swimming performance.
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Aletas de Animales , Peces , Animales , Fenómenos Biomecánicos , Aletas de Animales/fisiología , Peces/fisiología , Natación/fisiologíaRESUMEN
OBJECTIVE: To assess viewer engagement of a food advertising campaign on the live streaming platform Twitch.tv, a social media platform that allows creators to live stream content and communicate with their audience in real time. DESIGN: Observational analysis of chat comments across the Twitch platform containing the word 'Wendy's' or 'Wendys' during a 5-day ad campaign compared with two 5-day non-campaign time periods. Comments were categorised as positive, negative or neutral in how their sentiment pertained to the brand Wendy's. SETTING: Twitch chatrooms. PARTICIPANTS: None. RESULTS: There were significantly more chatroom messages related to the Wendy's brand during the campaign period. When considering all messages, the proportion of messages was statistically different (x2 = 1417·41, P < 0·001) across time periods, with a higher proportion of neutral and positive messages and a lower proportion of negative messages during the campaign compared with the comparison periods. Additionally, the proportion of negative messages following the campaign was lower than before the campaign. When considering only positive and negative messages, the proportion of messages was statistically different (x2 = 366·38, P < 0·001) across each time period with a higher proportion of positive messages and a lower proportion of negative messages during the campaign when compared with the other time periods. Additionally, there was a higher proportion of positive messages and a lower portion of negative messages following the campaign when compared with before the campaign. CONCLUSIONS: This study demonstrates the impact and sustained impact of a fast-food brand ad campaign on brand engagement on the live streaming platform Twitch.
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Spiders use various combinations of silks, adhesives, and behaviors to ensnare and trap prey. A common but difficult to catch prey in most spider habitats are moths. They easily escape typical orb-webs because their bodies are covered in sacrificial scales that flake off when in contact with the web's adhesives. This defense is defeated by spiders of the sub-family of Cyrtarachninae, moth-catching specialists who combine changes in orb-web structure, predatory behavior, and chemistry of the aggregate glue placed in those webs. The most extreme changes in web structure are shown by bolas spiders, who create a solitary capture strand containing only one or two glue droplets at the end of a single thread. They prey on male moths by releasing pheromones to draw them within range of their bolas, which they flick to ensnare the moth. We used a high-speed video camera to capture the behavior of the bolas spider Mastophora hutchinsoni. We calculated the kinematics of spiders and moths in the wild to model the physical and mechanical properties of the bolas during prey capture, the behavior of the moth, and how these factors lead to successful prey capture. We created a numerical model to explain the mechanical behavior of the bolas silk during prey capture. Our kinematic analysis shows that the material properties of the aggregate glue bolas of M. hutchinsoni are distinct from that of the other previously analyzed moth-specialist, Cyrtarachne akirai. The spring-like behavior of the M. hutchinsoni bolas suggests it spins a thicker liquid.
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The origin and early diversification of jawed vertebrates involved major changes to skeletal and soft anatomy. Skeletal transformations can be examined directly by studying fossil stem gnathostomes; however, preservation of soft anatomy is rare. We describe the only known example of a three-dimensionally mineralized heart, thick-walled stomach, and bilobed liver from arthrodire placoderms, stem gnathostomes from the Late Devonian Gogo Formation in Western Australia. The application of synchrotron and neutron microtomography to this material shows evidence of a flat S-shaped heart, which is well separated from the liver and other abdominal organs, and the absence of lungs. Arthrodires thus show the earliest phylogenetic evidence for repositioning of the gnathostome heart associated with the evolution of the complex neck region in jawed vertebrates.
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Evolución Biológica , Bagres , Fósiles , Animales , Bagres/anatomía & histología , Bagres/clasificación , Maxilares/anatomía & histología , Filogenia , Australia OccidentalRESUMEN
The lobe-finned fish, lungfish (Dipnoi, Sarcoptergii), have persisted for ~400 million years from the Devonian Period to present day. The evolution of their dermal skull and dentition is relatively well understood, but this is not the case for the central nervous system. While the brain has poor preservation potential and is not currently known in any fossil lungfish, substantial indirect information about it and associated structures (e.g. labyrinths) can be obtained from the cranial endocast. However, before the recent development of X-ray tomography as a palaeontological tool, these endocasts could not be studied non-destructively, and few detailed studies were undertaken. Here, we describe and illustrate the endocasts of six Palaeozoic lungfish from tomographic scans. We combine these with six previously described digital lungfish endocasts (4 fossil and 2 recent taxa) into a 12-taxon dataset for multivariate morphometric analysis using 17 variables. We find that the olfactory region is more highly plastic than the hindbrain, and undergoes significant elongation in several taxa. Further, while the semicircular canals covary as an integrated module, the utriculus and sacculus vary independently of each other. Functional interpretation suggests that olfaction has remained a dominant sense throughout lungfish evolution, and changes in the labyrinth may potentially reflect a change from nektonic to near-shore environmental niches. Phylogenetic implications show that endocranial form fails to support monophyly of the 'chirodipterids'. Those with elongated crania similarly fail to form a distinct clade, suggesting these two paraphyletic groups have converged towards either head elongation or truncation driven by non-phylogenetic constraints.
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Evolución Biológica , Fósiles , Animales , Encéfalo/diagnóstico por imagen , Peces , Paleontología , Cráneo/anatomía & histología , Cráneo/diagnóstico por imagenRESUMEN
Morphological structures and extended phenotypes are made possible by materials that are encoded by the genome. Nearly all biomaterials are viscoelastic, which means that to understand performance, one must understand the strain rate-dependent properties of these materials in relevant ecological interactions, as the behavior of a material can vary dramatically and rapidly. Spider silks are an example of materials whose properties vary substantially intra- and inter-specifically. Here, we focus on aggregate silk, which functions as a biological adhesive. As a case study to understand how a material manifests from genome through organism to ecology, we highlight moth-specialist spiders, the Cyrtarachninae, and their glues as an ideal experimental system to investigate the relationship between genomics and ecologically variable performance of a biological material. There is a clear eco-evolutionary innovation that Cyrtarachne akirai and related species have evolved, a unique trait not found in other spiders, a glue which overcomes the scales of moths. By examining traditional orb-weavers, C. akirai and other subfamily members using biomechanical testing and genomic analysis, we argue that we can track the evolution of this novel bioadhesive and comment on the selection pressures influencing prey specialization. The importance of the ecological context of materials testing is exemplified by the poor performance of C. akirai glue on glass and the exceptional spreading ability and adhesive strength on moths. The genetic basis for these performance properties is experimentally tractable because spider silk genes are minimally pleiotropic and advances in genomic technologies now make possible the discovery of complete silk gene sequences.