230 research outputs found
Scalar diagrammatic rules for Born amplitudes in QCD
We show that all Born amplitudes in QCD can be calculated from scalar
propagators and a set of three- and four-valent vertices. In particular, our
approach includes amplitudes with any number of quark pairs. The quarks may be
massless or massive. The proof of the formalism is given entirely within
quantum field theory.Comment: 20 pages, references adde
One-Loop MHV Amplitudes in Supersymmetric Gauge Theories
Using CSW rules for constructing scalar Feynman diagrams from MHV vertices,
we compute the contribution of chiral multiplet to one-loop
MHV gluon amplitude. The result agrees with the one obtained previously using
unitarity-based methods, thereby demonstrating the validity of the MHV-diagram
technique, in the case of one-loop MHV amplitudes, for all massless
supersymmetric theories.Comment: 20 pages, 5 figure
Recursion relations, Helicity Amplitudes and Dimensional Regularization
Using the method of on-shell recursion relations we compute tree level
amplitudes including D-dimensional scalars and fermions. These tree level
amplitudes are needed for calculations of one-loop amplitudes in QCD involving
external quarks and gluons.Comment: 28 pages, 6 figures, clarifications adde
Species-Related Differences in the Properties of Receptor-Operated TRPC4 Channels in Intestinal Myocytes of Rodents
TRPC4 proteins form receptor-operated cation channels that are activated in synergy by Mâ
and Mâ
acetylcholine (ACh) receptors coupled to Gq/11 and Gi/o proteins, respectively. These
channels are widely expressed in the brain and smooth muscles where they perform a number
of important functions, including control of GABA release from the dendrites and cholinergic
excitation of smooth muscles. The biophysical properties of TRPC4 currents directly activated
by GTPÎłS in mouse cells remain mostly unknown. We, thus, aimed to investigate these
channels in mouse ileal myocytes where a prominent TRPC4-mediated cation current termed
mICAT is observed, and to compare the behavior of this current with that of the better studied
mICAT in guinea-pig myocytes. Although the respective cation current responses to carbachol
(CCh) at â50 mV (i.e., at the value close to the normal resting potential in these cells) were
highly similar, mICAT in the mouse lacked the permissive action of intracellular Ca2+ on channel
opening. The slope factor of the muscarinic cation conductance, which is a defining property
of voltage-dependent behavior, was identical in both species. There were differences in the
potential at which the current peaked at negative potentials, but not in the maximal current
densities. Major differences were found in the kinetics of mICAT voltage-dependent relaxations,
which were much faster in the mouse. The above rodent species employ two different
strategies for the open probability increase by activated G-proteins; the mean open time was
shorter in the mouse compared to that in the guinea-pig (15.1 ± 5.2 msec, n = 8, vs. 80.0 ±
± 19.7 msec, n = 9; P < 0.01). Correspondingly, the instantaneous frequency of channel
opening was much higher in the mouse (154.1 ± 18.8 secâ»Âč vs. 70.2 ± 7.3 secâ»Âč in the guinea-pig;
P < 0.001). These functional differences are based on the differences found in the corresponding
TRPC4 amino acid sequences of the two rodent species, which are mainly clustered in the
cytosolic C-terminus of TRPC4 protein.
Keywords: muscarinic receptors, receptor-oĐŃĐŸŃĐ”ŃĐœĐž TRPC4 ŃĐŸŃĐŒŃŃŃŃ ŃĐ”ŃДпŃĐŸŃĐșĐ”ŃĐŸĐČĐ°ĐœŃ ĐșĐ°ŃŃĐŸĐœĐœŃ ĐșĐ°ĐœĐ°Đ»Đž, ŃĐșŃ Đ°ĐșŃĐžĐČŃŃŃŃŃŃ ŃĐžĐœĐ”ŃĐłŃŃĐœĐŸŃ ĐŽŃŃŃ ĐœĐ° Mâ
- ŃĐ° Mâ
-
Đ°ŃĐ”ŃОлŃ
ĐŸĐ»ŃĐœĐŸĐČŃ ŃĐ”ŃДпŃĐŸŃĐž, ĐČŃĐŽĐżĐŸĐČŃĐŽĐœĐŸ ĐżĐŸĐČâŃĐ·Đ°ĐœŃ Đ· Gq/11-
ŃĐ° Gi/o-ĐżŃĐŸŃĐ”ŃĐœĐ°ĐŒĐž. ĐŠŃ ĐșĐ°ĐœĐ°Đ»Đž ŃĐžŃĐŸĐșĐŸ Đ”ĐșŃĐżŃĐ”ŃĐŸĐČĐ°ĐœŃ ĐČ
ĐŒĐŸĐ·ĐșŃ ŃĐ° ĐłĐ»Đ°ĐŽĐ”ĐœŃĐșĐžŃ
ĐŒâŃĐ·Đ°Ń
, ĐŽĐ” ĐČĐŸĐœĐž ĐČĐžĐșĐŸĐœŃŃŃŃ ŃĐžŃĐ»Đ”ĐœĐœŃ
ŃŃĐœĐșŃŃŃ, ĐČ ŃĐŸĐŒŃ ŃĐžŃĐ»Ń Đ·Đ°Đ±Đ”Đ·ĐżĐ”ŃŃŃŃĐž ĐșĐŸĐœŃŃĐŸĐ»Ń ĐČĐžĐČŃĐ»ŃĐœĐ”ĐœĐœŃ
ĐĐĐĐ ŃĐ· ĐŽĐ”ĐœĐŽŃĐžŃŃĐČ ŃĐ° Ń
ĐŸĐ»ŃĐœĐ”ŃĐłŃŃĐœĐ” збŃĐŽĐ¶Đ”ĐœĐœŃ ĐłĐ»Đ°ĐŽĐ”ĐœŃĐșĐžŃ
ĐŒâŃĐ·ŃĐČ. ĐŃĐŸŃŃĐ·ĐžŃĐœŃ ĐČлаŃŃĐžĐČĐŸŃŃŃ ŃŃŃŃĐŒŃĐČ ŃĐ”ŃДз TRPC4-
ĐșĐ°ĐœĐ°Đ»Đž, ŃĐœĐŽŃĐșĐŸĐČĐ°ĐœĐžŃ
Ń ĐșĐ»ŃŃĐžĐœĐ°Ń
ĐŒĐžŃŃ ĐżŃŃĐŒĐŸŃ ĐŽŃŃŃ
ĐйЀγS, залОŃĐ°ŃŃŃŃŃ ĐČДлОĐșĐŸŃ ĐŒŃŃĐŸŃ ĐœĐ”ĐČŃĐŽĐŸĐŒĐžĐŒĐž. ĐąĐŸĐŒŃ ĐŒĐž
ĐŽĐŸŃĐ»ŃЎжŃĐČалО ŃŃ ĐșĐ°ĐœĐ°Đ»Đž ĐČ ĐŒŃĐŸŃĐžŃĐ°Ń
ŃĐŸĐœĐșĐŸĐłĐŸ ĐșĐžŃĐșŃĐČĐœĐžĐșĐ°
ĐŒĐžŃŃ, ĐČ ŃĐșĐžŃ
ŃĐżĐŸŃŃĐ”ŃŃгаŃŃŃŃŃ Đ·ĐœĐ°ŃĐœĐžĐč ĐșĐ°ŃŃĐŸĐœĐœĐžĐč ŃŃŃŃĐŒ, ĐŸĐżĐŸŃĐ”ŃДЎĐșĐŸĐČĐ°ĐœĐžĐč TRPC4 ŃĐ° ĐœĐ°Đ·ĐČĐ°ĐœĐžĐč mICAT. ĐĐž ĐżĐŸŃŃĐČĐœŃĐČалО
ĐČлаŃŃĐžĐČĐŸŃŃŃ ĐŽĐ°ĐœĐŸĐłĐŸ ŃŃŃŃĐŒŃ Đ· ĐČлаŃŃĐžĐČĐŸŃŃŃĐŒĐž ĐșŃĐ°ŃĐ” ĐČĐžĐČŃĐ”ĐœĐŸĐłĐŸ mICAT Ń ĐŒŃĐŸŃĐžŃĐ°Ń
ĐŒĐŸŃŃŃĐșĐŸŃ ŃĐČĐžĐœĐșĐž. ĐДзĐČажаŃŃĐž ĐœĐ° ŃĐ” ŃĐŸ ĐșĐ°ŃŃĐŸĐœĐœŃ ŃŃŃŃĐŒĐž ĐżŃŃĐ»Ń Đ°ĐżĐ»ŃĐșĐ°ŃŃŃ ĐșĐ°ŃбаŃ
ĐŸĐ»Ń ĐżŃĐž ĐżĐŸŃĐ”ĐœŃŃĐ°Đ»Ń â50 ĐŒĐ (ŃĐŸĐ±ŃĐŸ ĐżŃĐž Đ·ĐœĐ°ŃĐ”ĐœĐœŃ, блОзŃĐșĐŸĐŒŃ
ĐŽĐŸ ĐœĐŸŃĐŒĐ°Đ»ŃĐœĐŸĐłĐŸ ĐżĐŸŃĐ”ĐœŃŃĐ°Đ»Ń ŃĐżĐŸĐșĐŸŃ ĐČ ŃĐžŃ
ĐșĐ»ŃŃĐžĐœĐ°Ń
) бŃлО
ĐŽŃжД ĐżĐŸĐŽŃĐ±ĐœĐžĐŒĐž, ĐČплОĐČ ĐČĐœŃŃŃŃŃĐœŃĐŸĐșĐ»ŃŃĐžĐœĐœĐŸĐłĐŸ ĐșĐ°Đ»ŃŃŃŃ
ĐœĐ° ĐČŃĐŽĐșŃĐžĐČĐ°ĐœĐœŃ ĐŽĐŸŃĐ»ŃЎжŃĐČĐ°ĐœĐžŃ
ĐșĐ°ĐœĐ°Đ»ŃĐČ ĐżŃĐŽ ŃĐ°Ń ĐČŃĐŽĐČĐ”ĐŽĐ”ĐœĐœŃ
mICAT Ń ĐŒĐžŃŃ Đ±ŃĐČ ĐČŃĐŽŃŃŃĐœŃĐŒ. ĐšĐČОЎĐșŃŃŃŃ Đ·ĐŒŃĐœĐž ĐŒŃŃĐșĐ°ŃŃĐœĐŸĐČĐŸŃ
ĐșĐ°ŃŃĐŸĐœĐœĐŸŃ ĐżŃĐŸĐČŃĐŽĐœĐŸŃŃŃ, ĐșĐŸŃŃĐ° Ń ĐČĐžĐ·ĐœĐ°ŃĐ°Đ»ŃĐœĐžĐŒ ŃĐ°ĐșŃĐŸŃĐŸĐŒ
ŃĐŸĐŽĐŸ ĐżĐŸŃĐ”ĐœŃŃĐ°Đ»Đ·Đ°Đ»Đ”Đ¶ĐœĐŸŃ ĐżĐŸĐČДЎŃĐœĐșĐž ĐșĐ°ĐœĐ°Đ»ŃĐČ, Ń ĐŽĐČĐŸŃ
Đ·ĐłĐ°ĐŽĐ°ĐœĐžŃ
ĐČОЎŃĐČ ĐłŃОзŃĐœŃĐČ Đ±Ńла ĐżŃĐ°ĐșŃĐžŃĐœĐŸ ŃĐŽĐ”ĐœŃĐžŃĐœĐŸŃ. ĐĄĐżĐŸŃŃĐ”ŃŃгалОŃŃ
ĐżĐŸĐŒŃŃĐœŃ ŃĐŸĐ·Đ±ŃĐ¶ĐœĐŸŃŃŃ Đ·ĐœĐ°ŃĐ”ĐœŃ ĐœĐ”ĐłĐ°ŃĐžĐČĐœĐžŃ
ĐżĐŸŃĐ”ĐœŃŃĐ°Đ»ŃĐČ,
ĐżŃĐž ŃĐșĐžŃ
ŃŃŃŃĐŒ ĐŽĐŸŃŃгаĐČ ĐŒĐ°ĐșŃĐžĐŒŃĐŒŃ, алД ĐŒĐ°ĐșŃĐžĐŒĐ°Đ»ŃĐœŃ
ŃŃĐ»ŃĐœĐŸŃŃŃ ŃŃŃŃĐŒŃĐČ Đ±ŃлО ĐżĐŸĐŽŃĐ±ĐœĐžĐŒĐž. ĐĐ°ĐčбŃĐ»ŃŃŃ ĐČŃĐŽĐŒŃĐœĐœĐŸŃŃŃ
бŃлО ĐČĐžŃĐČĐ»Đ”ĐœŃ ĐČ ĐșŃĐœĐ”ŃĐžŃŃ ĐżĐŸŃĐ”ĐœŃŃĐ°Đ»Đ·Đ°Đ»Đ”Đ¶ĐœĐŸŃ ŃДлаĐșŃĐ°ŃŃŃ
mICAT, ĐșĐŸŃŃĐ° Ń ĐŒĐžŃŃ Đ±Ńла Đ·ĐœĐ°ŃĐœĐŸ ŃĐČОЎŃĐŸŃ. ĐŁ ĐČĐșĐ°Đ·Đ°ĐœĐžŃ
ĐČОЎŃĐČ ĐłŃОзŃĐœŃĐČ ĐČĐžĐșĐŸŃĐžŃŃĐŸĐČŃŃŃŃŃŃ ĐŽĐČŃ ĐČŃĐŽĐŒŃĐœĐœŃ ŃŃŃĐ°ŃДгŃŃ
ĐżŃĐŽĐČĐžŃĐ”ĐœĐœŃ ĐČŃŃĐŸĐłŃĐŽĐœĐŸŃŃŃ ĐČŃĐŽĐșŃĐžŃĐŸĐłĐŸ ŃŃĐ°ĐœŃ ĐŽĐŸŃĐ»ŃЎжŃĐČĐ°ĐœĐžŃ
ĐșĐ°ĐœĐ°Đ»ŃĐČ ĐżŃĐž Đ°ĐșŃĐžĐČĐ°ŃŃŃ G-ĐżŃĐŸŃĐ”ŃĐœŃĐČ. ĐĄĐ”ŃĐ”ĐŽĐœŃ Đ·ĐœĐ°ŃĐ”ĐœĐœŃ ŃĐ°ŃŃ
ĐČŃĐŽĐșŃĐžŃĐŸĐłĐŸ ŃŃĐ°ĐœŃ Ń ĐŒĐžŃŃ Đ±ŃĐ»ĐŸ Đ·ĐœĐ°ŃĐœĐŸ ĐŒĐ”ĐœŃĐžĐŒ ĐżĐŸŃŃĐČĐœŃĐœĐŸ Đ·
ĐČŃĐŽĐżĐŸĐČŃĐŽĐœĐžĐŒ ĐżĐŸĐșĐ°Đ·ĐœĐžĐșĐŸĐŒ Ń ĐŒĐŸŃŃŃĐșĐŸŃ ŃĐČĐžĐœĐșĐž (15.1 ± 5.2 ĐŒŃ,
n = 8, vs 80.0 ± 19.7 ĐŒŃ, n = 9; P < 0.01). ĐŃĐŽĐżĐŸĐČŃĐŽĐœĐŸ, Ń
ĐŒĐžŃŃ ĐŒĐžŃŃŃĐČĐ° ŃĐ°ŃŃĐŸŃĐ° ĐČŃĐŽĐșŃĐžĐČĐ°ĐœŃ ĐșĐ°ĐœĐ°Đ»ŃĐČ Đ±Ńла Đ·ĐœĐ°ŃĐœĐŸ ĐČĐžŃĐŸŃ, ĐœŃж Ń ĐŒĐŸŃŃŃĐșĐŸŃ ŃĐČĐžĐœĐșĐž (154.1 ± 18.8 Ńâ»Âč vs 70.2 ±
± 7.3 Ńâ»Âč; P < 0.001). ĐŠŃ ŃŃĐœĐșŃŃĐŸĐœĐ°Đ»ŃĐœŃ ŃŃĐ·ĐœĐžŃŃ ŃĐŸĐ·ĐłĐ»ŃĐŽĐ°ŃŃŃŃŃ ŃĐș ĐœĐ°ŃĐ»ŃĐŽĐŸĐș ŃŃŃŃĐșŃŃŃĐœĐžŃ
ŃĐŸĐ·Đ±ŃĐ¶ĐœĐŸŃŃĐ”Đč ĐČŃĐŽĐżĐŸĐČŃĐŽĐœĐžŃ
ĐżĐŸŃĐ»ŃĐŽĐŸĐČĐœĐŸŃŃĐ”Đč Đ°ĐŒŃĐœĐŸĐșĐžŃĐ»ĐŸŃĐœĐžŃ
залОŃĐșŃĐČ Ń Đ±ŃĐ»ĐșĐ°Ń
TRPC4
ĐŽĐČĐŸŃ
ĐČĐșĐ°Đ·Đ°ĐœĐžŃ
ĐČОЎŃĐČ ĐłŃОзŃĐœŃĐČ. ĐĐ°ĐœŃ ŃĐŸĐ·Đ±ŃĐ¶ĐœĐŸŃŃŃ ĐČ ĐŸŃĐœĐŸĐČĐœĐŸĐŒŃ ŃĐșĐŸĐœŃĐ”ĐœŃŃĐŸĐČĐ°ĐœŃ ĐČ ŃĐžŃĐŸĐ·ĐŸĐ»ŃĐœĐžŃ
C-Đ·Đ°ĐșŃĐœŃĐ”ĐœĐœŃŃ
пДŃĐČĐžĐœĐœĐžŃ
ĐżĐŸŃĐ»ŃĐŽĐŸĐČĐœĐŸŃŃĐ”Đč ĐżŃĐŸŃĐ”ŃĐœŃĐČ TRPC4
Commensal Neisseria species share immune suppressive mechanisms with Neisseria gonorrhoeae
Neisseria gonorrhoeae is a highly adapted human sexually transmitted pathogen that can cause symptomatic infections associated with localized inflammation as well as asymptomatic and subclinical infections, particularly in females. Gonococcal infection in humans does not generate an effective immune response in most cases, which contributes to both transmission of the pathogen and reinfection after treatment. Neisseria gonorrhoeae is known to evade and suppress human immune responses through a variety of mechanisms. Commensal Neisseria species that are closely related to N. gonorrhoeae, such as N. cinerea, N. lactamica, N. elongata, and N. mucosa, rarely cause disease and instead asymptomatically colonize mucosal sites for prolonged periods of time without evoking clearing immunologic responses. We have shown previously that N. gonorrhoeae inhibits the capacity of antigen-pulsed dendritic cells to induce CD4+ T cell proliferation in vitro. Much of the suppressive effects of N. gonorrhoeae on dendritic cells can be recapitulated either by outer-membrane vesicles released from the bacteria or by purified PorB, the most abundant outer-membrane protein in Neisseria gonorrhoeae. We show here that three commensal Neisseria species, N. cinerea, N. lactamica and N. mucosa, show a comparable capacity to suppress dendritic cell-induced T cell proliferation in vitro through mechanisms similar to those demonstrated previously for N. gonorrhoeae, including inhibition by purified PorB. Our findings suggest that some immune-evasive properties of pathogenic N. gonorrhoeae are shared with commensal Neisseria species and may contribute to the ability of both pathogens and commensals to cause prolonged mucosal colonization in humans
3D in Vitro Ultrasound Super-Resolution Imaging Using a Clinical System
© 2018 IEEE. Assessment of complex and disordered tumour vasculature requires full 3D visualization. Ultrasound super-resolution techniques are able to image microvascular structure and flow beyond the diffraction limit. Existing demonstrations have been predominantly 2D, where the elevational resolution remains restricted to around the millimeter range, while 3D demonstrations have either used mechanical scanning, or have required customized or state-of-the-art research systems to achieve true super-resolution in the third dimension. In this study, 3D super-resolution and velocity tracking is demonstrated in vitro using an ultrasound imaging system currently available in the clinic. This was performed at 1.25 MHz transmit frequency, with a frame rate of 54 Hz in contrast enhanced imaging mode. Three-dimensional super-resolved volumetric imaging of a twisted micro-vessel phantom was demonstrated at 3.5 cm depth, where between 66-70% of localizations where estimated to fall within the vessel internal diameter. Demonstration of 3D ultrasound super-resolution using a system currently available in the clinic demonstrates a fast route for clinical translation and application. In the future, 3D localization using microbubble signal onset could allow considerably improved microvascular visualization to aid early disease detection, diagnosis, and intervention for micro-vascular related diseases like cancer
3-D Motion Correction for Volumetric Super-Resolution Ultrasound Imaging
© 2018 IEEE. Motion during image acquisition can cause image degradation in all medical imaging modalities. This is particularly relevant in 2-D ultrasound imaging, since out-of-plane motion can only be compensated for movements smaller than elevational beamwidth of the transducer. Localization based super-resolution imaging creates even a more challenging motion correction task due to the requirement of a high number of acquisitions to form a single super-resolved frame. In this study, an extension of two-stage motion correction method is proposed for 3-D motion correction. Motion estimation was performed on high volumetric rate ultrasound acquisitions with a handheld probe. The capability of the proposed method was demonstrated with a 3-D microvascular flow simulation to compensate for handheld probe motion. Results showed that two-stage motion correction method reduced the average localization error from 136 to 18 Όm
Modern temporal network theory: A colloquium
The power of any kind of network approach lies in the ability to simplify a
complex system so that one can better understand its function as a whole.
Sometimes it is beneficial, however, to include more information than in a
simple graph of only nodes and links. Adding information about times of
interactions can make predictions and mechanistic understanding more accurate.
The drawback, however, is that there are not so many methods available, partly
because temporal networks is a relatively young field, partly because it more
difficult to develop such methods compared to for static networks. In this
colloquium, we review the methods to analyze and model temporal networks and
processes taking place on them, focusing mainly on the last three years. This
includes the spreading of infectious disease, opinions, rumors, in social
networks; information packets in computer networks; various types of signaling
in biology, and more. We also discuss future directions.Comment: Final accepted versio
Search for jet extinction in the inclusive jet-pT spectrum from proton-proton collisions at s=8 TeV
Published by the American Physical Society under the terms of the Creative Commons Attribution 3.0 License. Further distribution of this work must maintain attribution to the author(s) and the published articles title, journal citation, and DOI.The first search at the LHC for the extinction of QCD jet production is presented, using data collected with the CMS detector corresponding to an integrated luminosity of 10.7ââfbâ1 of proton-proton collisions at a center-of-mass energy of 8 TeV. The extinction model studied in this analysis is motivated by the search for signatures of strong gravity at the TeV scale (terascale gravity) and assumes the existence of string couplings in the strong-coupling limit. In this limit, the string model predicts the suppression of all high-transverse-momentum standard model processes, including jet production, beyond a certain energy scale. To test this prediction, the measured transverse-momentum spectrum is compared to the theoretical prediction of the standard model. No significant deficit of events is found at high transverse momentum. A 95% confidence level lower limit of 3.3 TeV is set on the extinction mass scale
Population and fertility by age and sex for 195 countries and territories, 1950â2017: a systematic analysis for the Global Burden of Disease Study 2017
Background: Population estimates underpin demographic and epidemiological research and are used to track progress on numerous international indicators of health and development. To date, internationally available estimates of population and fertility, although useful, have not been produced with transparent and replicable methods and do not use standardised estimates of mortality. We present single-calendar year and single-year of age estimates of fertility and population by sex with standardised and replicable methods. Methods: We estimated population in 195 locations by single year of age and single calendar year from 1950 to 2017 with standardised and replicable methods. We based the estimates on the demographic balancing equation, with inputs of fertility, mortality, population, and migration data. Fertility data came from 7817 location-years of vital registration data, 429 surveys reporting complete birth histories, and 977 surveys and censuses reporting summary birth histories. We estimated age-specific fertility rates (ASFRs; the annual number of livebirths to women of a specified age group per 1000 women in that age group) by use of spatiotemporal Gaussian process regression and used the ASFRs to estimate total fertility rates (TFRs; the average number of children a woman would bear if she survived through the end of the reproductive age span [age 10â54 years] and experienced at each age a particular set of ASFRs observed in the year of interest). Because of sparse data, fertility at ages 10â14 years and 50â54 years was estimated from data on fertility in women aged 15â19 years and 45â49 years, through use of linear regression. Age-specific mortality data came from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 estimates. Data on population came from 1257 censuses and 761 population registry location-years and were adjusted for underenumeration and age misreporting with standard demographic methods. Migration was estimated with the GBD Bayesian demographic balancing model, after incorporating information about refugee migration into the model prior. Final population estimates used the cohort-component method of population projection, with inputs of fertility, mortality, and migration data. Population uncertainty was estimated by use of out-of-sample predictive validity testing. With these data, we estimated the trends in population by age and sex and in fertility by age between 1950 and 2017 in 195 countries and territories. Findings: From 1950 to 2017, TFRs decreased by 49\ub74% (95% uncertainty interval [UI] 46\ub74â52\ub70). The TFR decreased from 4\ub77 livebirths (4\ub75â4\ub79) to 2\ub74 livebirths (2\ub72â2\ub75), and the ASFR of mothers aged 10â19 years decreased from 37 livebirths (34â40) to 22 livebirths (19â24) per 1000 women. Despite reductions in the TFR, the global population has been increasing by an average of 83\ub78 million people per year since 1985. The global population increased by 197\ub72% (193\ub73â200\ub78) since 1950, from 2\ub76 billion (2\ub75â2\ub76) to 7\ub76 billion (7\ub74â7\ub79) people in 2017; much of this increase was in the proportion of the global population in south Asia and sub-Saharan Africa. The global annual rate of population growth increased between 1950 and 1964, when it peaked at 2\ub70%; this rate then remained nearly constant until 1970 and then decreased to 1\ub71% in 2017. Population growth rates in the southeast Asia, east Asia, and Oceania GBD super-region decreased from 2\ub75% in 1963 to 0\ub77% in 2017, whereas in sub-Saharan Africa, population growth rates were almost at the highest reported levels ever in 2017, when they were at 2\ub77%. The global average age increased from 26\ub76 years in 1950 to 32\ub71 years in 2017, and the proportion of the population that is of working age (age 15â64 years) increased from 59\ub79% to 65\ub73%. At the national level, the TFR decreased in all countries and territories between 1950 and 2017; in 2017, TFRs ranged from a low of 1\ub70 livebirths (95% UI 0\ub79â1\ub72) in Cyprus to a high of 7\ub71 livebirths (6\ub78â7\ub74) in Niger. The TFR under age 25 years (TFU25; number of livebirths expected by age 25 years for a hypothetical woman who survived the age group and was exposed to current ASFRs) in 2017 ranged from 0\ub708 livebirths (0\ub707â0\ub709) in South Korea to 2\ub74 livebirths (2\ub72â2\ub76) in Niger, and the TFR over age 30 years (TFO30; number of livebirths expected for a hypothetical woman ageing from 30 to 54 years who survived the age group and was exposed to current ASFRs) ranged from a low of 0\ub73 livebirths (0\ub73â0\ub74) in Puerto Rico to a high of 3\ub71 livebirths (3\ub70â3\ub72) in Niger. TFO30 was higher than TFU25 in 145 countries and territories in 2017. 33 countries had a negative population growth rate from 2010 to 2017, most of which were located in central, eastern, and western Europe, whereas population growth rates of more than 2\ub70% were seen in 33 of 46 countries in sub-Saharan Africa. In 2017, less than 65% of the national population was of working age in 12 of 34 high-income countries, and less than 50% of the national population was of working age in Mali, Chad, and Niger. Interpretation: Population trends create demographic dividends and headwinds (ie, economic benefits and detriments) that affect national economies and determine national planning needs. Although TFRs are decreasing, the global population continues to grow as mortality declines, with diverse patterns at the national level and across age groups. To our knowledge, this is the first study to provide transparent and replicable estimates of population and fertility, which can be used to inform decision making and to monitor progress. Funding: Bill & Melinda Gates Foundation
- âŠ