129 research outputs found
How diet portfolio shifts combined with land-based climate change mitigation strategies could reduce climate burdens in Germany
Many studies have analysed the environmental impact of vegan, vegetarian, or reduced meat diets. To date, literature has not evaluated how diet shifts affect environmental impacts by utilising portfolios which reflect personal nutrition preferences. Further, changing diets could alter the available land for non-food uses. This paper defines novel diet portfolios to outline alternative diet transitions and choices within the population and finds their effect on greenhouse gas (GHG) emissions, primary energy use, and land use in Germany. The aim of this study is to capture how these diet shifts affect land availability and increase the options for land-based climate change mitigation strategies. To do so, a contextualisation is made to compare the use of freed-up land for afforestation or biomethane production (with and without carbon capture and storage). The investigated diet portfolios lead to a reduction of the investigated impacts (GHG emissions: 7–67%; energy use: 5–46%; land use: 6–64%). Additionally, afforestation of freed-up land from each diet portfolio leads to further emission removals of 4–37%. In comparison, using the land to produce energy crops for biomethane production could lead to 2–23% further CO2-eq emission reductions when replacing fossil methane. If biomethane production is paired with carbon capture and storage, emission abatement is increased to 3–34%. This research indicates various short-term pathways to reduce GHG emissions with portfolio diet shifts. Utilising freed-up land for climate change mitigation strategies could prove essential to meet climate targets, but trade-offs with, e.g. biodiversity and ecosystem services exist and should be considered
Deformed Skyrme Crystals
The Skyrme crystal, a solution of the Skyrme model, is the lowest
energy-per-charge configuration of skyrmions seen so far. Our numerical
investigations show that, as the period in various space directions is changed,
one obtains various other configurations, such as a double square wall, and
parallel vortex-like solutions. We also show that there is a sudden "phase
transition" between a Skyrme crystal and the charge 4 skyrmion with cubic
symmetry as the period is gradually increased in all three space directions.Comment: 13 pages, 6 figures. To be published in JHE
Magnetothermodynamics of BPS baby skyrmions
The magnetothermodynamics of skyrmion type matter described by the gauged BPS
baby Skyrme model at zero temperature is investigated. We prove that the BPS
property of the model is preserved also for boundary conditions corresponding
to an asymptotically constant magnetic field. The BPS bound and the
corresponding BPS equations saturating the bound are found. Further, we show
that one may introduce pressure in the gauged model by a redefinition of the
superpotential. Interestingly, this is related to non-extremal type solutions
in the so-called fake supersymmetry method. Finally, we compute the equation of
state of magnetized BSP baby skyrmions inserted into an external constant
magnetic field and under external pressure , i.e., , where
is the "volume" (area) occupied by the skyrmions. We show that the BPS baby
skyrmions form a ferromagnetic medium.Comment: Latex, 39 pages, 14 figures. v2: New results and references added,
physical interpretation partly change
Exotic Anti-Decuplet of Baryons: Prediction from Chiral Solitons
We predict an exotic Z^+ baryon (having spin 1/2, isospin 0 and strangeness
+1) with a relatively low mass of about 1530 MeV and total width of less than
15 MeV. It seems that this region of masses has avoided thorough searches in
the past.Comment: Revised version, to appear in Z. fuer Phys. A. The importance of 1/Nc
corrections to antidecuplet widths is demonstrated. 21 pages, 1 LaTeX figur
Charm CP Violation and the Electric Dipole Moments from the Charm Scale
The reported CP asymmetry in D->K^+K^- / pi^+pi^- is argued to be too large
to naturally fit the SM. If so, a new source of CP violation is implied in the
Delta C=1 sector with a milliweak strength. CP-odd interactions in the
flavor-diagonal sector are strongly constrained by the EDMs placing severe
limitations on the underlying theory. While the largest effects usually come
from the New Physics energy scale, they are strongly model-dependent. Yet the
interference of the CP-odd forces manifested in D decays with the conventional
CP-even Delta C=1 weak interaction generates at the charm scale a background
level. It has been argued that the d_n in the SM is largely generated via such
an interference, with mild KM-specific additional suppression. The reported CP
asymmetry is expected to generate d_n of 30 to 100 times larger than in the SM,
or even higher in certain model yet not quite natural examples. In the SM the
charm-induced loop-less |d_n| is expected around 10^{-31}e*cm. On the technical
side, we present a compact Ward-identity--based derivation of the induced
scalar pion-nucleon coupling in the presence of the CP-odd interactions, which
appears once the latter include the right-handed light quarks.Comment: 29pages, 5 figure
Labour Market Outcomes of Second Generation Immigrants: How Heterogeneous are They Really?
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