186 research outputs found
Timing and documentation of key events in neonatal resuscitation
Only a minority of babies require extended resuscitation at birth. Resuscitations concerning babies who die or who survive with adverse outcomes are increasingly subject to medicolegal scrutiny. Our aim was to describe real-life timings of key resuscitation events observed in a historical series of newborns who required full resuscitation at birth. Twenty-seven babies born in our centre over a 10-year period had an Apgar score of 0 at 1 min and required full resuscitation. The median (95% confidence interval) postnatal age at achieving key events were commencing cardiac compressions, 2.0 (1.5–4.0) min; endotracheal intubation, 3.8 (2.0–6.0) min; umbilical venous catheterisation 9.0 (7.5–12.0) min; and administration of first adrenaline dose 10.0 (8.0–14.0) min. Conclusion: The wide range of timings presented from real-life cases may prove useful to clinicians involved in medical negligence claims and provide a baseline for quality improvements in resuscitation training
Criteria for Drugs Used in Pre-Exposure Prophylaxis Trials against HIV Infection
The authors formulate criteria for an optimal pre-exposure prophylaxis drug candidate, and evaluate existing antiviral drug classes for their suitability
Enzymatic Activities and DNA Substrate Specificity of Mycobacterium tuberculosis DNA Helicase XPB
XPB, also known as ERCC3 and RAD25, is a 3′→5′ DNA repair helicase belonging to the superfamily 2 of helicases. XPB is an essential core subunit of the eukaryotic basal transcription factor complex TFIIH. It has two well-established functions: in the context of damaged DNA, XPB facilitates nucleotide excision repair by unwinding double stranded DNA (dsDNA) surrounding a DNA lesion; while in the context of actively transcribing genes, XPB facilitates initiation of RNA polymerase II transcription at gene promoters. Human and other eukaryotic XPB homologs are relatively well characterized compared to conserved homologs found in mycobacteria and archaea. However, more insight into the function of bacterial helicases is central to understanding the mechanism of DNA metabolism and pathogenesis in general. Here, we characterized Mycobacterium tuberculosis XPB (Mtb XPB), a 3′→5′ DNA helicase with DNA-dependent ATPase activity. Mtb XPB efficiently catalyzed DNA unwinding in the presence of significant excess of enzyme. The unwinding activity was fueled by ATP or dATP in the presence of Mg2+/Mn2+. Consistent with the 3′→5′ polarity of this bacterial XPB helicase, the enzyme required a DNA substrate with a 3′ overhang of 15 nucleotides or more. Although Mtb XPB efficiently unwound DNA model substrates with a 3′ DNA tail, it was not active on substrates containing a 3′ RNA tail. We also found that Mtb XPB efficiently catalyzed ATP-independent annealing of complementary DNA strands. These observations significantly enhance our understanding of the biological roles of Mtb XPB
Cutaneous lesions of the external ear
Skin diseases on the external aspect of the ear are seen in a variety of medical disciplines. Dermatologists, othorhinolaryngologists, general practitioners, general and plastic surgeons are regularly consulted regarding cutaneous lesions on the ear
Dating the Origin of Language Using Phonemic Diversity
Language is a key adaptation of our species, yet we do not know when it evolved. Here, we use data on language phonemic diversity to estimate a minimum date for the origin of language. We take advantage of the fact that phonemic diversity evolves slowly and use it as a clock to calculate how long the oldest African languages would have to have been around in order to accumulate the number of phonemes they possess today. We use a natural experiment, the colonization of Southeast Asia and Andaman Islands, to estimate the rate at which phonemic diversity increases through time. Using this rate, we estimate that present-day languages date back to the Middle Stone Age in Africa. Our analysis is consistent with the archaeological evidence suggesting that complex human behavior evolved during the Middle Stone Age in Africa, and does not support the view that language is a recent adaptation that has sparked the dispersal of humans out of Africa. While some of our assumptions require testing and our results rely at present on a single case-study, our analysis constitutes the first estimate of when language evolved that is directly based on linguistic data
Context, cognition and communication in language
Questions pertaining to the unique structure and organisation of language have a
long history in the field of linguistics. In recent years, researchers have explored
cultural evolutionary explanations, showing how language structure emerges from
weak biases amplified over repeated patterns of learning and use. One outstanding
issue in these frameworks is accounting for the role of context. In particular,
many linguistic phenomena are said to to be context-dependent; interpretation
does not take place in a void, and requires enrichment from the current state
of the conversation, the physical situation, and common knowledge about the
world. Modelling the relationship between language structure and context is
therefore crucial for developing a cultural evolutionary approach to language.
One approach is to use statistical analyses to investigate large-scale, cross-cultural
datasets. However, due to the inherent limitations of statistical analyses, especially
with regards to the inadequacy of these methods to test hypotheses about
causal relationships, I argue that experiments are better suited to address questions
pertaining to language structure and context. From here, I present a series
of artificial language experiments, with the central aim being to test how
manipulations to context influence the structure and organisation of language.
Experiment 1 builds upon previous work in iterated learning and communication
games through demonstrating that the emergence of optimal communication systems
is contingent on the contexts in which languages are learned and used. The
results show that language systems gradually evolve to only encode information
that is informative for conveying the intended meaning of the speaker - resulting
in markedly different systems of communication. Whereas Experiment 1 focused
on how context influences the emergence of structure, Experiments 2 and 3 investigate
under what circumstances do manipulations to context result in the loss
of structure. While the results are inconclusive across these two experiments,
there is tentative evidence that manipulations to context can disrupt structure,
but only when interacting with other factors. Lastly, Experiment 4 investigates
whether the degree of signal autonomy (the capacity for a signal to be interpreted without recourse to contextual information) is shaped by manipulations
to contextual predictability: the extent to which a speaker can estimate and exploit
contextual information a hearer uses in interpreting an utterance. When
the context is predictable, speakers organise languages to be less autonomous
(more context-dependent) through combining linguistic signals with contextual
information to reduce effort in production and minimise uncertainty in comprehension.
By decreasing contextual predictability, speakers increasingly rely on
strategies that promote more autonomous signals, as these signals depend less on
contextual information to discriminate between possible meanings. Overall, these
experiments provide proof-of-concept for investigating the relationship between
language structure and context, showing that the organisational principles underpinning
language are the result of competing pressures from context, cognition,
and communication
THE ANTIPREDATOR VOCALIZATIONS OF ADULT EASTERN SCREECH-OWLS
Volume: 28Start Page: 93End Page: 9
Outcome of babies with no detectable heart rate before 10 minutes of age, and the effect of gestation
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