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Geophysical Research Letters
No full textAbstract We quantify the impact of ocean eddies on the global-mean tropical-cyclone intensity in a 1-year simulation run with a coupled atmosphere-ocean model with quite-realistic seasonal climatology that resolves both Tropical cyclones (TCs) and ocean eddies. We find a significantly lower global-mean intensity and intensification rate for the subset of TCs that spend more time over cold-core eddies than warm-core eddies. While not statistically significant, we also find that TCs that encounter more warm than cold-core eddies display a higher global-mean intensity and intensification rate. The differing impact of warm-core and cold-core ocean eddies are consistent with coherent differences in sea-surface cooling prior to peak intensity. Our results demonstrate that ocean eddies can have a statistically significant impact on the global-mean intensity, suggesting that resolving ocean eddies does matter for global TC statistics
Exploring contemporary pastoral variability through stable isotope analysis in the Turkana Basin, Kenya
No full textIn some contexts, the term “pastoralism” still invokes a perception of unchanging specialized dietary reliance on herd animals. This is despite the fact that research from across multiple disciplines has emphasized pastoral economic heterogeneity and its spatial and temporal variability, consistent with shifting contextual factors. While diverse accounts attest to dynamic subsistence strategies, direct dietary assessments of the complex interactions between herding and cultivating groups in pastoralist contexts and in terms of seasonal subsistence have been limited. This paper uses stable carbon (δ13C), nitrogen (δ15N), and hydrogen (δ2H) isotope analysis of modern human hair from the Turkana of northern Kenya, as well as hair from their herd animals, to explore differences in diet between herders and riverside cultivators—communities involved in different economic activities that are nevertheless part of a single broader sociocultural grouping. Sampling during the wet and dry seasons also facilitates exploration of adaptive responses to precipitation change. Limited dietary differences between more specialized herders and riverside cultivators support views of pastoralism as a highly dynamic adaptive strategy, with greater reliance on herd animals only on a seasonal basis.Katika baadhi ya maeneo, tafsiri ya neno “ufugaji” bado limebeba nadharia ya jamii isiobadilika na inayotegemea mazao ya wanyama tu kama sehemu ya lishe. Mtizamo huu umeendelea kuwepo pamoja na ukweli kwamba tafiti mbalimbali zimekwisha kuainisha na kutilia mkazo mchangamano na utofauti wa kiuchumi wa jamii ya wafugaji kulingana na umri na maeneo husika. Wakati zipo taarifa mbalimbali zinazoainisha uwepo wa utofauti katika dhana ya mazao ya chakula, ushahidi wa moja kwa moja unaonesha misimu ya mwingiliano kati wafugaji na wakulima katika maeneo ya wafugaji bado ni hadimu/hafifu. Makala hii inatumia sampuli za isotopu ya kaboni (δ13C), naitrojeni (δ15N), na hidrojeni (δ2H) zilizokusanywa kwenye nywele za watu wa jamii ya wafugaji na manyoya ya wanyama wawafugao katika eneo la Turkana linalopatikana kaskazini mwa Kenya. Madhumuni ya utafiti huu ilikua kuchunguza utofauti wa mazao ya chakula kati ya jamii ya wafugaji na wakulima wanaoishi kando kando ya mto/vijito ambapo jamii hii pia hujihusisha na shughuli mbalimbali katika mazingira ya eneo moja linalowazunguka. Sampuli zilizokusanywala katika vipindi vya mvua na vipindi vya ukame vinatoa taswira ya namna gani watu wameweza kukabiliana na mabadiliko ya hali ya hewa. Uhaba wa ushahidi wa utofauti wa mavuno ya chakula kati ya jamii ya wafugaji na wakulima ni ushahidi kwamba, jamii ya wafugaji imekua na mkakati wa mabadiliko ya mavuno ya chakula ambapo mazao ya wanyama yanakua tegemezi kwa msimu maalumu tu.Introduction The Turkana Pastoral Economy Investigating Pastoral Lifeways in Eastern Africa Using Stable Isotope Analysis Material and Methods Study Area Hair Sample Collection Interviews Pretreatment of Hair Samples d13C and d15N Analysis d2H Analysis Statistical Analysis Results d13C and d15N Results 2H Results Discussion Conclusio
Conservative Black Hole Scattering at Fifth Post-Minkowskian and Second Self-Force Order
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Purely equatorial lasing in spherical liquid crystal polymer microlasers with engineered refractive index gradient
No full textLiquid crystal whispering gallery mode microlasers show high sensitivity to external stimuli and distinct spectral features, rendering them ideally suited for various sensing applications. They also offer intrinsic anisotropic optical properties, which can be used to shape and manipulate light even inside spatially highly symmetric structures. Here, we report the synthesis and detailed optical characterization of a spherical bipolar liquid crystal polymer microlaser that tightly confines the optical path of whispering gallery modes to the equatorial plane. By controlled anchoring of the liquid crystal mesogens followed by polymerization, a fixed refractive index gradient is formed within the spherical microcavity. Consequently, only transverse electric (TE) modes oscillating in the equatorial plane experience the high extraordinary refractive index, allowing to confine lasing into a single plane. Furthermore, we observe that the refractive index gradient causes a characteristic splitting of the TE modes. By combining hyperspectral imaging and analytical modeling, we demonstrate that the observed splitting is caused by lifting of the energy degeneracy of higher order azimuthal laser modes, enabling direct insights into the complex interplay of refractive index gradients and resulting whispering gallery mode confinement. In addition, the unique ability to confine lasing of a spherical microbead into only a single plane makes these microlasers independent of the exact position of the pump beam, which allows consistent localized sensing especially in combination with fast point scanning microscopes or inside highly dynamic biological environments
The C. elegans nervous system reads the internal state of the hydrogen peroxidedetoxification machinery to trigger escape from this common reactive chemical
No full textHydrogen peroxide (H2O2) is the most common reactive chemical threat faced by organisms. Here, we map the neural circuit that drives chemotactic escape from environmental H2O2 in the nematode C. elegans. Twenty-four neuron classes with sensory endings at the mouth and nose of the animal detect H2O2. Their response dynamics encode stimulus intensity and exposure history, and their partial redundancy makes avoidance resilient to the loss of individual inputs. Sensing begins when H2O2 oxidizes the peroxidatic and resolving cysteines of the cytosolic peroxiredoxin PRDX-2, which relays this oxidative signal to cysteines on the LITE-1 and GUR-3 ion channels, triggering calcium influx in sensory neurons that drive escape. Most of these neurons release glutamate to drive H2O2-dependent excitation of AIA interneurons, whereas others signal through non-glutamatergic routes, providing multiple routes for signal transmission. Thus, the C. elegans nervous system acts as a hydrogen peroxide sentinel that monitors H2O2-induced changes in the intracellular H2O2-detoxification machinery and relays them to interneurons driving organism-wide escape. This raises the possibility that circuit defects in aging and neurodegenerative disease arise from altered peroxiredoxin-mediated H2O2 signaling rather than primarily from direct macromolecular damage