1,672 research outputs found
Study of the mechanisms of transmission of respiratory-tract pathogenic bacteria
Pulmonary tuberculosis is contracted mainly by
inhalation into the lungs of small airborne infected
dust -particles liberated from handkerchiefs, clothes,
bedding and carpets which have been soiled by the
sputum or by the large projectile cough- droplets of '
patients.
A much less important, but possibly not rare,
mode of infection is by inhalation of small infected
droplet- nuclei introduced into the air by the
coughing of patients.
A third, and probably rare, mode of infection is
by ingestion into the mouth, on fingers or eating
utensils, of tubercle bacilli acquired from patients
by contact, with subsequent aspiration of the bacilli,
probably in small droplets of saliva, from mouth to
lungs via the trachea.
Tubercle bacilli acquired by ingestion, and
invading the body through the tonsils or intestines,
do not give rise to pulmonary tuberculosis apart
from military lung infection due to haematogenous
spread from a primary alimentary-tract lesion
How chimpanzees (Pan troglodytes) share the spoils with collaborators and bystanders
The study was funded by the Max Planck Society. S. Duguid wrote the manuscript supported by a grant awarded to A. P. Melis from the Templeton World Charity Foundation (TWCF0264).Chimpanzees hunt cooperatively in the wild, but the factors influencing food sharing after the hunt are not well understood. In an experimental study, groups of three captive chimpanzees obtained a monopolizable food resource, either via two individuals cooperating (with the third as bystander) or via one individual acting alone alongside two bystanders. The individual that obtained the resource first retained most of the food but the other two individuals attempted to obtain food from the "captor" by begging. We found the main predictor of the overall amount of food obtained by bystanders was proximity to the food at the moment it was obtained by the captor. Whether or not an individual had cooperated to obtain the food had no effect. Interestingly, however, cooperators begged more from captors than did bystanders, suggesting that they were more motivated or had a greater expectation to obtain food. These results suggest that while chimpanzee captors in cooperative hunting may not reward cooperative participation directly, cooperators may influence sharing behavior through increased begging.Publisher PDFPeer reviewe
Phylogeographic structure of brown trout (Salmo trutta) in Britain and Ireland: glacial refugia, post-glacial colonisation, and origins of sympatric populations
The dispersion of spherical droplets in source–sink flows and their relevance to the COVID-19 pandemic
In this paper, we investigate the dynamics of spherical droplets in the
presence of a source-sink pair flow field. The dynamics of the droplets is
governed by the Maxey-Riley equation with Basset-Boussinesq history term
neglected. We find that, in the absence of gravity, there are two distinct
behaviours for the droplets: small droplets cannot go further than a specific
distance, which we determine analytically, from the source before getting
pulled into the sink. Larger droplets can travel further from the source before
getting pulled into the sink by virtue of their larger inertia, and their
maximum travelled distance is determined analytically.
We investigate the effects of gravity, and we find that there are three
distinct droplet behaviours categorised by their relative sizes: small,
intermediate-sized, and large. Counterintuitively, we find that the droplets
with minimum horizontal range are neither small nor large, but of intermediate
size. Furthermore, we show that in conditions of regular human respiration,
these intermediate-sized droplets range in size from a few m to a few
hundred m. The result that such droplets have a very short range could
have important implications for the interpretation of existing data on droplet
dispersion.Comment: 14 pages, 7 figure
Coverage gaps in empiric antibiotic regimens used to treat serious bacterial infections in neonates and children in Southeast Asia and the Pacific
Background: High levels of antimicrobial resistance (AMR) are propagating deaths due to neonatal and paediatric infections globally. This is of particular concern in Southeast Asia and the Pacific, where healthcare resources are constrained and access to newer agents to treat multidrug-resistant pathogens is limited.
Methods: To assess the coverage provided by commonly prescribed empiric antibiotic regimens for children in low- and middle-income countries in Southeast Asia and the Pacific, we built a weighted incidence syndromic combination antibiogram (WISCA), parameterised using data obtained from a systematic review of published literature incorporating WHO-defined SEARO and WPRO regions in Ovid MEDLINE, EMBASE, Global Health and PubMed. Susceptibility data for bacterial pathogens were extracted to provide coverage estimates for pre-specified antibiotics (aminopenicillins, gentamicin, third-generation cephalosporins and carbapenems), reported at the regional level.
Findings: 6648 bacterial isolates from 11 countries across 86 papers were included in the Bayesian WISCA model, which weighted bacterial incidence and antimicrobial susceptibility of relevant isolates. Coverage provided by aminopenicillins in neonatal sepsis/meningitis was 26% (80% credible interval: 16–49) whilst gentamicin coverage was 45% (29–62). Third-generation cephalosporin coverage was only 29% (16–49) in neonatal sepsis/meningitis, 51% (38–64) in paediatric sepsis and 65% (51–77) in paediatric meningitis. Carbapenems were estimated to provide the highest coverage: 81% (65–90) in neonatal sepsis/meningitis, 83% (72–90) in paediatric sepsis and 79% (62–91) in paediatric meningitis.
Interpretation: These findings reveal alarmingly high rates of resistance to commonly prescribed empirical therapies for neonatal and paediatric sepsis and meningitis in the Asia–Pacific region
A sense of embodiment is reflected in people's signature size
BACKGROUND: The size of a person's signature may reveal implicit information about how the self is perceived although this has not been closely examined. METHODS/RESULTS: We conducted three experiments to test whether increases in signature size can be induced. Specifically, the aim of these experiments was to test whether changes in signature size reflect a person's current implicit sense of embodiment. Experiment 1 showed that an implicit affect task (positive subliminal evaluative conditioning) led to increases in signature size relative to an affectively neutral task, showing that implicit affective cues alter signature size. Experiments 2 and 3 demonstrated increases in signature size following experiential self-focus on sensory and affective stimuli relative to both conceptual self-focus and external (non-self-focus) in both healthy participants and patients with anorexia nervosa, a disorder associated with self-evaluation and a sense of disembodiment. In all three experiments, increases in signature size were unrelated to changes in self-reported mood and larger than manipulation unrelated variations. CONCLUSIONS: Together, these findings suggest that a person's sense of embodiment is reflected in their signature size
Current and Calcium Responses to Local Activation of Axonal NMDA Receptors in Developing Cerebellar Molecular Layer Interneurons
In developing cerebellar molecular layer interneurons (MLIs), NMDA increases spontaneous GABA release. This effect had been attributed to either direct activation of presynaptic NMDA receptors (preNMDARs) or an indirect pathway involving activation of somato-dendritic NMDARs followed by passive spread of somatic depolarization along the axon and activation of axonal voltage dependent Ca2+ channels (VDCCs). Using Ca2+ imaging and electrophysiology, we searched for preNMDARs by uncaging NMDAR agonists either broadly throughout the whole field or locally at specific axonal locations. Releasing either NMDA or glutamate in the presence of NBQX using short laser pulses elicited current transients that were highly sensitive to the location of the spot and restricted to a small number of varicosities. The signal was abolished in the presence of high Mg2+ or by the addition of APV. Similar paradigms yielded restricted Ca2+ transients in interneurons loaded with a Ca2+ indicator. We found that the synaptic effects of NMDA were not inhibited by blocking VDCCs but were impaired in the presence of the ryanodine receptor antagonist dantrolene. Furthermore, in voltage clamped cells, bath applied NMDA triggers Ca2+ elevations and induces neurotransmitter release in the axonal compartment. Our results suggest the existence of preNMDARs in developing MLIs and propose their involvement in the NMDA-evoked increase in GABA release by triggering a Ca2+-induced Ca2+ release process mediated by presynaptic Ca2+ stores. Such a mechanism is likely to exert a crucial role in various forms of Ca2+-mediated synaptic plasticity
Adsorption of mono- and multivalent cat- and anions on DNA molecules
Adsorption of monovalent and multivalent cat- and anions on a deoxyribose
nucleic acid (DNA) molecule from a salt solution is investigated by computer
simulation. The ions are modelled as charged hard spheres, the DNA molecule as
a point charge pattern following the double-helical phosphate strands. The
geometrical shape of the DNA molecules is modelled on different levels ranging
from a simple cylindrical shape to structured models which include the major
and minor grooves between the phosphate strands. The densities of the ions
adsorbed on the phosphate strands, in the major and in the minor grooves are
calculated. First, we find that the adsorption pattern on the DNA surface
depends strongly on its geometrical shape: counterions adsorb preferentially
along the phosphate strands for a cylindrical model shape, but in the minor
groove for a geometrically structured model. Second, we find that an addition
of monovalent salt ions results in an increase of the charge density in the
minor groove while the total charge density of ions adsorbed in the major
groove stays unchanged. The adsorbed ion densities are highly structured along
the minor groove while they are almost smeared along the major groove.
Furthermore, for a fixed amount of added salt, the major groove cationic charge
is independent on the counterion valency. For increasing salt concentration the
major groove is neutralized while the total charge adsorbed in the minor groove
is constant. DNA overcharging is detected for multivalent salt. Simulations for
a larger ion radii, which mimic the effect of the ion hydration, indicate an
increased adsorbtion of cations in the major groove.Comment: 34 pages with 14 figure
The Web will kill them all: new media, digital utopia, and political struggle in the Italian 5-Star Movement
This article examines the role of discourses about
new media technology and the Web in the
rise of the 5-Star Movement (Movimento 5 Stelle, or
M5S) in Italy. Founded by comedian and
activist Beppe Grillo and Web entrepreneur Gianrobe
rto Casaleggio in 2009, this movement
succeeded in becoming the second largest party at t
he 2013 national elections in Italy. This
article aims to discuss how elements of digital uto
pia and Web-centric discourses have been
inserted into the movement’s political message, and
how the construction of the Web as a myth
has shaped the movement’s discourse and political p
ractice. The 5-Star Movement is compared
and contrasted with other social and political move
ments in Western countries which have
displayed a similar emphasis on new media, such as
the Occupy movement, the Indignados
movement, and the Pirate Parties in Sweden and Germ
any. By adopting and mutating cyber-
utopian discourses from the so-called Californian i
deology, the movement symbolically identifies
itself with the Web. The traditional political esta
blishment is associated with “old” media
(television, radio, and the printed press), and rep
resented as a “walking dead,” doomed to be
superseded and buried by a Web-based direct democra
cy
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