Search results for "VARIABILITY"
showing 10 items of 904 documents
Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years
2021
Significance The variability of the Asian summer monsoon (ASM) is important for the functioning of ecological and societal systems at regional to continental scales, but the long-term evolution and interannual variability of this system is not well understood. Here, we present a stable isotope–based reconstruction of ASM variability covering 4680 BCE to 2011 CE. Superimposed on a gradual drying trend, a rapid drop in mean annual precipitation (>40%) toward persistently drier conditions occurred in ∼1675 BCE. This megadrought caused regional forest deterioration and enhanced aeolian activity affecting Chinese ecosystems. We argue that this abrupt aridification starting ∼2000 BCE triggered wa…
Climate variability, innovation and firm performance: evidence from the European agricultural sector
2021
Abstract It is generally accepted that adaptation to climate variability requires a technological advancement strategy. However, the innovation process has received little explicit consideration in this framework. We employ a panel endogenous switching regression model to explore whether and to what extent climate variability affects firm performance through the ability to induce the development of adaptation innovations in key resource-based sectors in Europe during the period 2007–2017. Our findings confirm that the knowledge generation process at the heart of climate change adaptation technologies enhances firm performance, especially for firms in the aquaculture and fishing sub-sectors …
Evidence for a link between the Atlantic Multidecadal Oscillation and annual asthma mortality rates in the US
2019
AbstractAn association between climatic conditions and asthma mortality has been widely assumed. However, it is unclear whether climatic variations have a fingerprint on asthma dynamics over long time intervals. The aim of this study is to detect a possible correlation between climatic indices, namely the Atlantic Multidecadal Oscillation and Pacific Decadal Oscillation, and asthma mortality rates over the period from 1950 to 2015 in the contiguous US. To this aim, an analysis of non-stationary and non-linear signals was performed on time series of US annual asthma mortality rates, AMO and PDO indices to search for characteristic periodicities. Results revealed that asthma death rates evalu…
Polygenic association between attention-deficit/hyperactivity disorder liability and cognitive impairments.
2022
AbstractBackgroundA recent genome-wide association study (GWAS) identified 12 independent loci significantly associated with attention-deficit/hyperactivity disorder (ADHD). Polygenic risk scores (PRS), derived from the GWAS, can be used to assess genetic overlap between ADHD and other traits. Using ADHD samples from several international sites, we derived PRS for ADHD from the recent GWAS to test whether genetic variants that contribute to ADHD also influence two cognitive functions that show strong association with ADHD: attention regulation and response inhibition, captured by reaction time variability (RTV) and commission errors (CE).MethodsThe discovery GWAS included 19 099 ADHD cases …
Shift-Invariant Canonical Polyadic Decomposition of Complex-Valued Multi-Subject fMRI Data with a Phase Sparsity Constraint
2020
Canonical polyadic decomposition (CPD) of multi-subject complex-valued fMRI data can be used to provide spatially and temporally shared components among groups with both magnitude and phase information. However, the CPD model is not well formulated due to the large subject variability in the spatial and temporal modalities, as well as the high noise level in complex-valued fMRI data. Considering that the shift-invariant CPD can model temporal variability across subjects, we propose to further impose a phase sparsity constraint on the shared spatial maps to denoise the complex-valued components and to model the inter-subject spatial variability as well. More precisely, subject-specific time …
Heart rate variability in marketing research: A systematic review and methodological perspectives
2022
Abstract Heart rate variability is a promising physiological measurement that accesses psychophysiological variations in response to a marketing stimulus. While its application spans diverse fields, there is a limited understanding of the usability and interpretation of heart rate variability in marketing research. Therefore, this hybrid literature review provides an overview of the emerging use of heart rate variability in marketing research, along with essential methodological considerations. In this context, we blend marketing mix framework with stimulus-organism-response theory, segregating the use of heart rate variability in various marketing research contexts. We follow the preferred…
A meta-analysis on heart rate variability biofeedback and depressive symptoms
2021
Heart rate variability biofeedback (HRVB) has been used for a number of years to treat depressive symptoms, a common mental health issue, which is often comorbid with other psychopathological and medical conditions. The aim of the present meta-analysis is to test whether and to what extent HRVB is effective in reducing depressive symptoms in adult patients. We conducted a literature search on Pubmed, ProQuest, Ovid PsycInfo, and Embase up to October 2020, and identified 721 studies. Fourteen studies were included in the meta-analysis. Three meta-regressions were also performed to further test whether publication year, the questionnaire used to assess depressive symptoms, or the interval of …
Glycaemic variability (measured by 48h continous glucose monitoring) in subjects with metabolic syndrome, with ot withoout diabetes,is indipendently …
2007
Postprandial hyperglycaemia induces endothelial dysfunction thus contributing to the appearance of atherosclerotic lesions and to the high cardiovascular risk of diabetic subjects. Subjects who develop diabetes have an increased cardiovascular risk even before the appearance of diabetes. Insulin resistant subjects with metabolic syndrome (MS) are at both high cardiovascular and diabetes risk and it cannot be excluded that higher postprandial glycaemic excursions might induce endothelial dysfunction in this condition. Furthermore, adipose tissue is known to release factors (adipokines) that are able to influence both insulin sensitivity and endothelial function. The glycaemic variability is …