Local Histories/Global Designsis an extended argument about the "coloniality" of power by one of the most innovative Latin American and Latino scholars. In a shrinking world where sharp dichotomies, ...such as East/West and developing/developed, blur and shift, Walter Mignolo points to the inadequacy of current practices in the social sciences and area studies. He explores the crucial notion of "colonial difference" in the study of the modern colonial world and traces the emergence of an epistemic shift, which he calls "border thinking." Further, he expands the horizons of those debates already under way in postcolonial studies of Asia and Africa by dwelling in the genealogy of thoughts of South/Central America, the Caribbean, and Latino/as in the United States. His concept of "border gnosis," or sensing and knowing by dwelling in imperial/colonial borderlands, counters the tendency of occidentalist perspectives to manage, and thus limit, understanding.
In a new preface that discussesLocal Histories/Global Designsas a dialogue with Hegel's Philosophy of History, Mignolo connects his argument with the unfolding of history in the first decade of the twenty-first century.
We construct perturbative classical solutions of the Yang-Mills equations coupled to dynamical point particles carrying color charge. By applying a set of color to kinematics replacement rules first ...introduced by Bern, Carrasco and Johansson, these are shown to generate solutions of d-dimensional dilaton gravity, which we also explicitly construct. Agreement between the gravity result and the gauge theory double copy implies a correspondence between non-Abelian particles and gravitating sources with dilaton charge. When the color sources are highly relativistic, dilaton exchange decouples, and the solutions we obtain match those of pure gravity. We comment on possible implications of our findings to the calculation of gravitational waveforms in astrophysical black hole collisions, directly from computationally simpler gluon radiation in Yang-Mills theory.
A brief history of masting research Koenig, Walter D
Philosophical transactions of the Royal Society of London. Series B. Biological sciences,
12/2021, Letnik:
376, Številka:
1839
Journal Article
Recenzirano
Odprti dostop
Although it has long been recognized that seed production by many forest trees varies greatly from year to year, masting (along with 'mast fruiting', 'mast seeding' and 'masting behaviour') as a ...concept referring to such variability is a relatively recent development. Here, I provide a brief history of masting research, highlighting some of the early contributions by foresters, zoologists and others that paved the way for the burgeoning number of studies currently being conducted by researchers around the world. Of particular current interest is work attempting to understand the proximate mechanisms, evolutionary drivers and community effects of this important ecological phenomenon as well as the ways that climate change may influence masting behaviour in the future. This article is part of the theme issue 'The ecology and evolution of synchronized seed production in plants'.
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bstract
We extend Shen’s recent formulation (arXiv:1806.07388) of the classical double copy, based on explicit color-kinematic duality, to the case of finite-size sources with non-zero spin. For ...the case of spinning Yang-Mills sources, the most general consistent double copy consists of gravitating objects which carry pairs of spin degrees of freedom. We find that the couplings of such objects to background fields match those of a classical (i.e. heavy) closed bosonic string, suggesting a string theory interpretation of sources related by color-kinematics duality. As a special case, we identify a limit, corresponding to unoriented strings, in which the 2-form Kalb-Ramond axion field decouples from the gravitational side of the double copy. Finally, we apply the classical double copy to extended objects, described by the addition of finite-size operators to the worldline effective theory. We find that consistency of the color-to-kinematics map requires that the Wilson coefficients of tidal operators obey certain relations, indicating that the extended gravitating objects generated by the double copy of Yang-Mills are not completely generic.
Once upon a time scholars assumed that the knowing subject in the disciplines is transparent, disincorporated from the known and untouched by the geo-political configuration of the world in which ...people are racially ranked and regions are racially configured. From a detached and neutral point of observation (that Colombian philosopher Santiago Castro-Gómez describes as the hubris of the zero point ), the knowing subject maps the world and its problems, classifies people and projects into what is good for them. Today that assumption is no longer tenable, although there are still many believers. At stake is indeed the question of racism and epistemology. And once upon a time scholars assumed that if you ‘come’ from Latin America you have to ‘talk about’ Latin America; that in such a case you have to be a token of your culture. Such expectation will not arise if the author ‘comes’ from Germany, France, England or the US. As we know: the first world has knowledge, the third world has culture; Native Americans have wisdom, Anglo Americans have science. The need for political and epistemic de-linking here comes to the fore, as well as decolonializing and decolonial knowledges, necessary steps for imagining and building democratic, just, and nonimperial/colonial societies.
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bstract
We generalize the worldline EFT formalism developed in 4–9 to calculate the non-conservative tidal effects on spinning black holes in a long wavelength approximation that is valid to all ...orders in the magnitude of the spin. We present results for the rate of change of mass and angular momentum in a background field and find agreement with previous calculations obtained by different techniques. We also present new results for both the non-conservative equations of motion and power loss/gain for a binary inspiral, which start at 5PN and 2.5PN order respectively and manifest the Penrose process.
Mechanisms of mast seeding Pearse, Ian S.; Koenig, Walter D.; Kelly, Dave
The New phytologist,
November 2016, Letnik:
212, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Mast seeding is a widespread and widely studied phenomenon. However, the physiological mechanisms that mediate masting events and link them to weather and plant resources are still debated. Here, we ...explore how masting is affected by plant resource budgets, fruit maturation success, and hormonal coordination of cues including weather and resources. There is little empirical support for the commonly stated hypothesis that plants store carbohydrates over several years to expend in a high-seed year. Plants can switch carbohydrates away from growth in high-seed years, and seed crops are more probably limited by nitrogen or phosphorus. Resources are clearly involved in the proximate mechanisms driving masting, but resource budget (RB) models cannot create masting in the absence of selection because some underlying selective benefit is required to set the level of a ‘full’ seed crop at greater than the annual resource increment. Economies of scale (EOSs) provide the ultimate factor selecting for masting, but EOSs probably always interact with resources, which modify the relationship between weather cues and reproduction. Thus, RB and EOS models are not alternative explanations for masting – both are required. Experiments manipulating processes that affect mast seeding will help clarify the physiological mechanisms that underlie mast seeding.
This Commentary article deals with the important role of large‐amplitude, short‐duration (<1 hr) and southwardly directed magnetic field incursions within the Sheath region of an interplanetary ...coronal mass ejection, which were recently shown to have led to extreme auroral activity during the early part of the Halloween storm (Ohtani, 2022, https://doi.org/10.1029/2022ja030596). For such largely geoeffective magnetic field structures some suggestions are given toward their possible interplanetary causes, which could also be associated with the origin of similar Sheath‐structures observed during other events with very intense geomagnetic activity. A particular attention is given to a Sheath‐incorporated and largely geoeffective flux rope‐hypothesis. At the end we add some comments on further related magnetospheric and space weather issues.
Plain Language Summary
In this Commentary article suggestions are given on possible interplanetary processes that could be associated with the formation of short‐lived and strongly geoeffective (very intense geomagnetic activity) magnetic field structures that were observed in the Sheath (frontside) region of an interplanetary coronal mass ejection that arrived at the Earth's magnetosphere early during the very intense geomagnetically‐active time interval of October 29‐30, 2003, also known a “Halloween storm.” The suggested interplanetary processes are also expected to be associated with the origin of similar Sheath‐structures observed during other events with extreme and short‐lasting geomagnetic activity. At the end we add some comments on further related magnetospheric and space weather issues.
Key Points
This article deals with the role of large‐amplitude, short‐duration and southwardly directed Interplanetary magnetic field within the Sheath region of an interplanetary coronal mass ejection
A Sheath‐incorporated and largely geoeffective flux rope‐hypothesis is suggested
Some implications of the commented material on related magnetospheric and space weather issues are also presented
We extend the perturbative double copy between radiating classical sources in gauge theory and gravity to the case of spinning particles. We construct, to linear order in spins, perturbative ...radiating solutions to the classical Yang-Mills equations sourced by a set of interacting color charges with chromomagnetic dipole spin couplings. Using a color-to-kinematics replacement rule proposed earlier by one of the authors, these solutions map onto radiation in a theory of interacting particles coupled to massless fields that include the graviton, a scalar (dilaton) ϕ and the Kalb-Ramond axion field Bμν. Consistency of the double copy imposes constraints on the parameters of the theory on both the gauge and gravity sides of the correspondence. In particular, the color charges carry a chromomagnetic interaction which, in d=4, corresponds to a gyromagnetic ratio equal to Dirac’s value g=2. The color-to-kinematics map implies that on the gravity side, the bulk theory of the fields (ϕ,gμν,Bμν) has interactions which match those of d-dimensional “string gravity,” as is the case both in the BCJ double copy of pure gauge theory scattering amplitudes and the KLT relations between the tree-level S-matrix elements of open and closed string theory.
We extend the perturbative classical double copy to the analysis of bound systems. We first obtain the leading order perturbative gluon radiation field sourced by a system of interacting color ...charges in arbitrary time dependent orbits, and test its validity by taking relativistic bremsstrahlung and nonrelativistic bound state limits. By generalizing the color to kinematic replacement rules recently used in the context of classical bremsstrahlung, we map the gluon emission amplitude to the radiation fields of dilaton gravity sourced by interacting particles in generic (self-consistent) orbits. As an application, we reproduce the leading post-Newtonian radiation fields and energy flux for point masses in nonrelativistic orbits from the double copy of gauge theory.
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