The diverse functional roles of over 6,000 species of extant mammals that range in body size across eight orders of magnitude, from blue whales (Balaenoptera musculus) to tiny Etruscan shrews (Suncus ...etruscus), contribute to shaping Earth's ecosystems. Large mammalian herbivores (e.g., African elephants Loxodonta africana, American bison Bison bison, hippopotamuses Hippopotamus amphibius) and carnivores (e.g., wolves Canis lupus, pumas Puma concolor, sea otters Enhydra lutris) often have significant effects on primary producers in terrestrial, aquatic, and marine systems through nutrient cycling, energy flow, and the exertion of bottom-up and top-down processes. Small mammals, like bats, are important pollinators, dispersers of fruits, and consumers of arthropods, and others, especially rodents and primates, are important predators and dispersers of seeds. Many of these mammal-mediated processes occur simultaneously in the same ecosystem, and have significant effects on community structure of primary producers that in turn alter communities of other vertebrates and invertebrates. Many mammals also are ecosystem engineers (e.g., elephants, American beavers Castor canadensis, porcupines Erithezon dorsatum, prairie dogs Cynomys spp.) that create, significantly modify, or destroy habitat, and by doing so, they alter ecosystem structure and function and increase habitat heterogeneity and biodiversity. The extensive influence mammals have on ecosystems results in important services that contribute to human well-being, such as pollination, insect pest control, and bioturbation of soils. The rapid declines in abundance of many mammal populations and the associated increase in extinction risk raise conservation concerns for mammals. To maintain mammalian diversity and the critical ecosystem processes they provide, scientists need to mobilize concern for their status and strive for more effective and comprehensive conservation action. We provide insights and synthesis on the ecological role of mammals and highlight key research questions and future directions for their conservation.
Cardiovascular disease is a major leading cause of morbidity and mortality in the United States and elsewhere. Alterations in mitochondrial function are increasingly being recognized as a ...contributing factor in myocardial infarction and in patients presenting with cardiomyopathy. Recent understanding of the complex interaction of the mitochondria in regulating metabolism and cell death can provide novel insight and therapeutic targets. The purpose of this statement is to better define the potential role of mitochondria in the genesis of cardiovascular disease such as ischemia and heart failure. To accomplish this, we will define the key mitochondrial processes that play a role in cardiovascular disease that are potential targets for novel therapeutic interventions. This is an exciting time in mitochondrial research. The past decade has provided novel insight into the role of mitochondria function and their importance in complex diseases. This statement will define the key roles that mitochondria play in cardiovascular physiology and disease and provide insight into how mitochondrial defects can contribute to cardiovascular disease; it will also discuss potential biomarkers of mitochondrial disease and suggest potential novel therapeutic approaches.
Recent reports of myocardial recovery after mechanical unloading with left ventricular assist devices (LVADs) have challenged the prevailing notion that end-stage heart failure (HF) is irreversible. ...To improve our understanding of this phenomenon, we comprehensively analysed the structural, functional, and energetic changes in failing human cardiomyocytes after LVAD implantation.
Based on a prospectively registered protocol (PROSPERO-CRD42022380214), 30 eligible studies were identified from 940 records with a pooled population of 648 patients predominantly with non-ischaemic cardiomyopathy.
LVAD led to a substantial regression in myocyte size similar to that of donor hearts (standardised mean difference, −1.29; p<0.001). The meta-regression analysis revealed that HF duration was a significant modifier on the changes in myocyte size. There were some suggestions of fibrosis reversal (−5.17%; p=0.009); however, this was insignificant after sensitivity analysis. Developed force did not improve in cardiac trabeculae (n=5 studies); however, non-physiological isometric contractions were tested. At the myocyte level (n=4 studies), contractile kinetics improved where the time-to-peak force reduced by 41.7%–50.7% and time to 50% relaxation fell by 47.4%–62.1% (p<0.05). Qualitatively, LVAD enhanced substrate utilisation and mitochondrial function (n=6 studies). Most studies were at a high risk of bias.
The regression of maladaptive hypertrophy, partial fibrosis reversal, and normalisation in metabolic pathways after LVAD may be a testament to the heart’s remarkable plasticity, even in the advanced stages of HF. However, inconsistencies exist in force-generating capabilities. Using more physiological force-length work-loop assays, addressing the high risks of bias and clinical heterogeneity are crucial to better understand the phenomenon of reverse remodelling.
Un contact vibratoire avec les éléments Claire Revol; Pascaline Thiollière; Sébastien de Pertat ...
Socio-anthropologie,
12/2023, Letnik:
48
Journal Article
Recenzirano
Odprti dostop
This contribution looks at occidental geomancy practices called « geobiology », based on a survey initiated in 2020 in the Alpine region around the Grenoble urban region. Geobiology refers to a set ...of ways of feeling that are attentive to terrestrial, telluric and cosmic energies, mobilized for the purpose of caring for humans and animals or harmonizing the habitat. Based on a few examples of how we come into contact with these phenomena mobilizing different modalities of internal senses and somatic experience, we’ll show that they involve cosmologies that situate human beings between sky and earth, and manifest themselves in sensitive relationships with living environments.
Background
Nonalcoholic fatty liver disease (NAFLD) is linked to a raised risk of cardiovascular diseases (CVD), although the underlying mechanisms are not completely known. A reduced myocardial ...mechano‐energetic efficiency (MEE) has been found to be an independent predictor of CVD.
Objective
To evaluate the association between NAFLD and a compromised MEE.
Methods
Myocardial MEE was assessed by a validated echocardiography‐derived measure in 699 nondiabetic individuals subdivided into two groups according to ultrasonography defined presence of NAFLD.
Results
Subjects with NAFLD displayed higher levels of systolic (SBP) and diastolic blood pressure (DBP), triglycerides, fasting and postload glucose, high‐sensitivity C‐reactive protein (hsCRP), insulin resistance (IR) estimated by HOMA‐IR and liver IR index, and lower values of high‐density lipoprotein (HDL) in comparison with those without NAFLD. Presence of NAFLD was associated with increased levels of myocardial oxygen demand and reduced values of MEE. MEE was negatively correlated with male sex, age, BMI, waist circumference, SBP, DBP, total cholesterol, triglycerides, fasting and postload glucose, HOMA‐IR and liver IR index, hsCRP and positively with HDL levels. In a multivariable regression analysis, presence of NAFLD was associated with MEE regardless of several cardio‐metabolic risk factors such as age, gender, waist circumference, SBP, DBP, total and HDL cholesterol, triglycerides, glucose tolerance and hsCRP (β = −0.09, P = 0.04), but not independently of IR estimates.
Conclusion
Ultrasound‐defined presence of NAFLD is associated with a decreased MEE, a predictor of adverse cardiovascular events. The relationship between NAFLD and a compromised MEE is dependent of IR.
•Intraseasonal fluctuations in the abyssal South China Sea are characterized.•The variabilities are closely related to topographic and planetary Rossby waves.•Surface perturbations serve as the major ...energy source for the deep fluctuations.•Energy is radiated across layers through pressure work and damped by dissipation.•This study highlights a universality in the intraseasonal energetics of deep ocean.
Energetics of the abyssal ocean account greatly for the redistribution and dissipation of global oceanic energy. In this study, we characterize the intraseasonal fluctuations in the deep South China Sea (SCS) and evaluate the relevant energy budget using observations and numerical simulations. The results indicate substantial geographical inhomogeneity in the intraseasonal energy reservoir. The high-energy zones are located in the northwest of the Luzon Strait, northern slopes, deep western boundary current region, and southwestern cyclonic gyre region, where the intraseasonal fluctuations account for about 70% of the deep energy variability. Vorticity and divergence patterns of the intraseasonal motions are suggestive of quasigeostrophic dynamics, which are mostly attributed to the hybrid topographic–planetary Rossby waves. The flow field exhibits a weak lateral shear and appears to have symmetric instability with negative vorticity skewness, particularly over the sloping topography. Energetics analysis demonstrates that the intraseasonal fluctuations in the abyssal SCS obtain energy primarily from the upper layer through pressure work, while secondarily from advective transport and cross-scale transfer due to instability of the deep circulation. To reach equilibrium, the energy gained is mostly damped by dissipations. As another reference in the marginal sea with intensive mixing, our study highlights the potential universality in how the intraseasonal energy is fueled and dissipated in the abyss.
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