8,970 research outputs found
Recommended from our members
Responding to Climate Change: The Economy and Economics - Part of the Problem and Solution
The Climate Change Starterās Guide provides an introduction and overview for education planners and practitioners on the wide range of issues relating to climate change and climate change education, including causes, impacts, mitigation and adaptation strategies, as well as some broad political and economic principles.
The aim of this guide is to serve as a starting point for mainstreaming climate change education into school curricula. It has been created to enable education planners and practitioners to understand the issues at hand, to review and analyse their relevance to particular national and local contexts, and to facilitate the development of education policies, curricula, programmes and lesson plans.
The guide covers four major thematic areas:
1. the science of climate change, which explains the causes and observed changes;
2. the social and human aspects of climate change including gender, health, migration, poverty and ethics;
3. policy responses to climate change including measures for mitigation and adaptation; and
4. education approaches including education for sustainable development, disaster reduction and sustainable lifestyles.
A selection of key resources in the form of publication titles or websites for further reading is provided after each of the thematic sections
Regional cerebral blood flow changes as a function of delta and spindle activity during slow wave sleep in humans
In the present study, we investigated changes in regional cerebral blood flow (rCBF) in humans during the progression from relaxed wakefulness through slow wave sleep (SWS). These changes were examined as a function of spindle (12-15 Hz) and delta (1.5-4.0 Hz) electroencephalographic (EEG) activity of SWS. rCBF was studied with positron emission tomography (PET) using the H215O bolus method. A maximum of six 60 sec scans were performed per subject during periods of wakefulness and stages 1-4 of SWS, as determined by on-line EEG monitoring. Spectral analysis was performed off-line on the EEG epochs corresponding to the scans for computation of activity in specific frequency bands. The relationship between EEG frequency band activity and normalized rCBF was determined by means of a voxel-by-voxel analysis of covariance. delta activity covaried negatively with rCBF most markedly in the thalamus and also in the brainstem reticular formation, cerebellum, anterior cingulate, and orbitofrontal cortex. After the effect of delta was removed, a significant negative covariation between spindle activity and the residual rCBF was evident in the medial thalamus. These negative covariations may reflect the disfacilitation and active inhibition of thalamocortical relay neurons in association with delta and spindles, as well as the neural substrates underlying the progressive attenuation of sensory awareness, motor responsiveness, and arousal that occur during SWS. delta activity covaried positively with rCBF in the visual and auditory cortex, possibly reflecting processes of dream-like mentation purported to occur during SW
TRPV1-expressing primary afferents generate behavioral responses to pruritogens via multiple mechanisms
The mechanisms that generate itch are poorly understood at both the molecular and cellular levels despite its clinical importance. To explore the peripheral neuronal mechanisms underlying itch, we assessed the behavioral responses (scratching) produced by s.c. injection of various pruritogens in PLCĪ²3- or TRPV1-deficient mice. We provide evidence that at least 3 different molecular pathways contribute to the transduction of itch responses to different pruritogens: 1) histamine requires the function of both PLCĪ²3 and the TRPV1 channel; 2) serotonin, or a selective agonist, Ī±-methyl-serotonin (Ī±-Me-5-HT), requires the presence of PLCĪ²3 but not TRPV1, and 3) endothelin-1 (ET-1) does not require either PLCĪ²3 or TRPV1. To determine whether the activity of these molecules is represented in a particular subpopulation of sensory neurons, we examined the behavioral consequences of selectively eliminating 2 nonoverlapping subsets of nociceptors. The genetic ablation of MrgprD^+ neurons that represent ā90% of cutaneous nonpeptidergic neurons did not affect the scratching responses to a number of pruritogens. In contrast, chemical ablation of the central branch of TRPV1+ nociceptors led to a significant behavioral deficit for pruritogens, including Ī±-Me-5-HT and ET-1, that is, the TRPV1-expressing nociceptor was required, whether or not TRPV1 itself was essential. Thus, TRPV1 neurons are equipped with multiple signaling mechanisms that respond to different pruritogens. Some of these require TRPV1 function; others use alternate signal transduction pathways
High affinity germinal center B cells are actively selected into the plasma cell compartment
A hallmark of T cellādependent immune responses is the progressive increase in the ability of serum antibodies to bind antigen and provide immune protection. Affinity maturation of the antibody response is thought to be connected with the preferential survival of germinal centre (GC) B cells that have acquired increased affinity for antigen via somatic hypermutation of their immunoglobulin genes. However, the mechanisms that drive affinity maturation remain obscure because of the difficulty in tracking the affinity-based selection of GC B cells and their differentiation into plasma cells. We describe a powerful new model that allows these processes to be followed as they occur in vivo. In contrast to evidence from in vitro systems, responding GC B cells do not undergo plasma cell differentiation stochastically. Rather, only GC B cells that have acquired high affinity for the immunizing antigen form plasma cells. Affinity maturation is therefore driven by a tightly controlled mechanism that ensures only antibodies with the greatest possibility of neutralizing foreign antigen are produced. Because the body can sustain only limited numbers of plasma cells, this āquality controlā over plasma cell differentiation is likely critical for establishing effective humoral immunity
- ā¦