Cardiac parasympathetic activity may be non-invasively investigated using heart rate variability (HRV), although HRV is not widely accepted to reflect sympathetic activity. Instead, cardiac ...sympathetic activity may be investigated using systolic time intervals (STI), such as the pre-ejection period. Although these autonomic indices are typically measured during rest, the "reactivity hypothesis" suggests that investigating responses to a stressor (e.g., exercise) may be a valuable monitoring approach in clinical and high-performance settings. However, when interpreting these indices it is important to consider how the exercise dose itself (i.e., intensity, duration, and modality) may influence the response. Therefore, the purpose of this investigation was to review the literature regarding how the exercise dosage influences these autonomic indices during exercise and acute post-exercise recovery. There are substantial methodological variations throughout the literature regarding HRV responses to exercise, in terms of exercise protocols and HRV analysis techniques. Exercise intensity is the primary factor influencing HRV, with a greater intensity eliciting a lower HRV during exercise up to moderate-high intensity, with minimal change observed as intensity is increased further. Post-exercise, a greater preceding intensity is associated with a slower HRV recovery, although the dose-response remains unclear. A longer exercise duration has been reported to elicit a lower HRV only during low-moderate intensity and when accompanied by cardiovascular drift, while a small number of studies have reported conflicting results regarding whether a longer duration delays HRV recovery. "Modality" has been defined multiple ways, with limited evidence suggesting exercise of a greater muscle mass and/or energy expenditure may delay HRV recovery. STI responses during exercise and recovery have seldom been reported, although limited data suggests that intensity is a key determining factor. Concurrent monitoring of HRV and STI may be a valuable non-invasive approach to investigate autonomic stress reactivity; however, this integrative approach has not yet been applied with regards to exercise stressors.
Human immune system variation Brodin, Petter; Davis, Mark M
Nature reviews. Immunology,
01/2017, Volume:
17, Issue:
1
Journal Article
Peer reviewed
Open access
The human immune system is highly variable between individuals but relatively stable over time within a given person. Recent conceptual and technological advances have enabled systems immunology ...analyses, which reveal the composition of immune cells and proteins in populations of healthy individuals. The range of variation and some specific influences that shape an individual's immune system is now becoming clearer. Human immune systems vary as a consequence of heritable and non-heritable influences, but symbiotic and pathogenic microbes and other non-heritable influences explain most of this variation. Understanding when and how such influences shape the human immune system is key for defining metrics of immunological health and understanding the risk of immune-mediated and infectious diseases.
The science and medicine of human immunology Pulendran, Bali; Davis, Mark M
Science (American Association for the Advancement of Science),
09/2020, Volume:
369, Issue:
6511
Journal Article
Peer reviewed
Open access
Although the development of effective vaccines has saved countless lives from infectious diseases, the basic workings of the human immune system are complex and have required the development of ...animal models, such as inbred mice, to define mechanisms of immunity. More recently, new strategies and technologies have been developed to directly explore the human immune system with unprecedented precision. We discuss how these approaches are advancing our mechanistic understanding of human immunology and are facilitating the development of vaccines and therapeutics for infection, autoimmune diseases, and cancer.
Hadley cell expansion in CMIP6 models Grise, Kevin M; Davis, Sean M
Atmospheric chemistry and physics,
05/2020, Volume:
20, Issue:
9
Journal Article
Peer reviewed
Open access
In response to increasing greenhouse gases, the
subtropical edges of Earth's Hadley circulation shift poleward in global
climate models. Recent studies have found that reanalysis trends in the
Hadley ...cell edge over the past 30–40 years are within the range of trends
simulated by Coupled Model Intercomparison Project Phase 5 (CMIP5) models
and have documented seasonal and hemispheric asymmetries in these trends. In
this study, we evaluate whether these conclusions hold for the newest
generation of models (CMIP6). Overall, we find similar characteristics of
Hadley cell expansion in CMIP5 and CMIP6 models. In both CMIP5 and CMIP6
models, the poleward shift of the Hadley cell edge in response to increasing
greenhouse gases is 2–3 times larger in the Southern Hemisphere (SH),
except during September–November. The trends from CMIP5 and CMIP6 models
agree well with reanalyses, although prescribing observed coupled
atmosphere–ocean variability allows the models to better capture reanalysis
trends in the Northern Hemisphere (NH). We find two notable differences
between CMIP5 and CMIP6 models. First, while both CMIP5 and CMIP6 models
contract the NH summertime Hadley circulation equatorward (particularly over
the Pacific sector), this contraction is larger in CMIP6 models due to their
higher average climate sensitivity. Second, in recent decades, the poleward
shift of the NH annual-mean Hadley cell edge is slightly larger in CMIP6
models. Increasing greenhouse gases drive similar trends in CMIP5 and CMIP6
models, so the larger recent NH trends in CMIP6 models point to the role of
other forcings, such as aerosols.
ABSTRACT
We re-analyse data from the gravitational-wave event GW170817 and its host galaxy NGC 4993 to demonstrate the importance of accurate total and peculiar velocities when measuring the Hubble ...constant using this nearby standard siren. We show that a number of reasonable choices can be made to estimate the velocities for this event, but that systematic differences remain between these measurements depending on the data used. This leads to significant changes in the Hubble constant inferred from GW170817. We present Bayesian model averaging as one way to account for these differences, and obtain $H_{0}=66.8^{+13.4}_{-9.2}\, \mathrm{km\, s^{-1}\, Mpc^{-1}}$. Adding additional information on the viewing angle from high-resolution imaging of the radio counterpart refines this to $H_{0}=64.8^{+7.3}_{-7.2}\, \mathrm{km\, s^{-1}\, Mpc^{-1}}$. During this analysis, we also present an alternative Bayesian model for the posterior on H0 from standard sirens that works more closely with observed quantities from redshift and peculiar velocity surveys. Our results more accurately capture the true uncertainty on the total and peculiar velocities of NGC 4993 and show that exploring how well different data sets characterize galaxy groups and the velocity field in the local Universe could improve this measurement further. These considerations impact any low-redshift distance measurement, and the improvements we suggest here can also be applied to standard candles like Type Ia supernovae. GW170817 is particularly sensitive to peculiar velocity uncertainties because it is so close. For future standard siren measurements, the importance of this error will decrease as (i) we will measure more distant standard sirens and (ii) the random direction of peculiar velocities will average out with more detections.
At present, transgenes in Caenorhabditis elegans are generated by injecting DNA into the germline. The DNA assembles into a semistable extrachromosomal array composed of many copies of injected DNA. ...These transgenes are typically overexpressed in somatic cells and silenced in the germline. We have developed a method that inserts a single copy of a transgene into a defined site. Mobilization of a Mos1 transposon generates a double-strand break in noncoding DNA. The break is repaired by copying DNA from an extrachromosomal template into the chromosomal site. Homozygous single-copy insertions can be obtained in less than 2 weeks by injecting approximately 20 worms. We have successfully inserted transgenes as long as 9 kb and verified that single copies are inserted at the targeted site. Single-copy transgenes are expressed at endogenous levels and can be expressed in the female and male germlines.
Full text
Available for:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
There is considerable heterogeneity in immunological parameters between individuals, but its sources are largely unknown. To assess the relative contribution of heritable versus non-heritable ...factors, we have performed a systems-level analysis of 210 healthy twins between 8 and 82 years of age. We measured 204 different parameters, including cell population frequencies, cytokine responses, and serum proteins, and found that 77% of these are dominated (>50% of variance) and 58% almost completely determined (>80% of variance) by non-heritable influences. In addition, some of these parameters become more variable with age, suggesting the cumulative influence of environmental exposure. Similarly, the serological responses to seasonal influenza vaccination are also determined largely by non-heritable factors, likely due to repeated exposure to different strains. Lastly, in MZ twins discordant for cytomegalovirus infection, more than half of all parameters are affected. These results highlight the largely reactive and adaptive nature of the immune system in healthy individuals.
Display omitted
•Non-heritable influences explain much of the variation in immune measurements•Immune parameters become more divergent between MZ twins with increasing age•A single non-heritable factor affects more than 50% of all cell subsets and serum proteins•Heritable and non-heritable immune measurements are largely interdependent
An extensive analysis of the immune systems of healthy humans shows that non-heritable factors such as infections, vaccines, and nutrition largely determine immune system variation and that the influence of such non-heritable factors can be both broad and cumulative, overshadowing most heritable influences with time.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
: media-1vid110.1542/5840360268001PEDS-VA_2018-1235
BACKGROUND: Childhood food allergy (FA) is a life-threatening chronic condition that substantially impairs quality of life. This large, ...population-based survey estimates childhood FA prevalence and severity of all major allergenic foods. Detailed allergen-specific information was also collected regarding FA management and health care use.
A survey was administered to US households between 2015 and 2016, obtaining parent-proxy responses for 38 408 children. Prevalence estimates were based on responses from NORC at the University of Chicago's nationally representative, probability-based AmeriSpeak Panel (51% completion rate), which were augmented by nonprobability-based responses via calibration weighting to increase precision. Prevalence was estimated via weighted proportions. Multiple logistic regression models were used to evaluate FA predictors.
Overall, estimated current FA prevalence was 7.6% (95% confidence interval: 7.1%-8.1%) after excluding 4% of children whose parent-reported FA reaction history was inconsistent with immunoglobulin E-mediated FA. The most prevalent allergens were peanut (2.2%), milk (1.9%), shellfish (1.3%), and tree nut (1.2%). Among food-allergic children, 42.3% reported ≥1 severe FA and 39.9% reported multiple FA. Furthermore, 19.0% reported ≥1 FA-related emergency department visit in the previous year and 42.0% reported ≥1 lifetime FA-related emergency department visit, whereas 40.7% had a current epinephrine autoinjector prescription. Prevalence rates were higher among African American children and children with atopic comorbidities.
FA is a major public health concern, affecting ∼8% of US children. However, >11% of children were perceived as food-allergic, suggesting that the perceived disease burden may be greater than previously acknowledged.
PDF
