1,500 research outputs found
To Complicity… and Beyond! Passive Assistance and Positive Obligations in International Law
Despite an apparent determination by the International Court of Justice that complicity under Article 16 ASR can only result from positive acts, it will be argued that a State may be responsible for complicity through passive assistance. Though complicity by omission has received academic acknowledgement, the concept is unduly restricted; posited as contingent on a pre-existing positive obligation to act, and thus necessarily entailing a violation of this primary norm. If this is so, complicity creates a duality of responsibility and is arguably rendered redundant, as it will always be easier to show that a State violated this positive obligation, than successfully leap the many hurdles of Article 16 ASR. This understanding of passive complicity will be challenged on a number of grounds, ultimately leading to the assertion that international law does recognise a useful concept of passive assistance, distinct and untethered from positive obligations. This is termed ‘complicity by inaction’ – passive assistance that is not per se wrongful
Morphometric parameters of clavicles among adult Black people in Tanzania
Morphological clavicular variation has been studied extensively by orthopaedic surgeons, anatomic and forensic experts to explain developmental, gender and age-related differences. The design of fixation devices for displaced clavicular fracture management depends largely on anatomic characteristics of clavicle. Eighty-one unpaired clavicles of unknown sex were studied, 42 clavicles were of right side and 39 clavicles of left side. All the clavicles were collected from adult cadavers which were dissected in Departments of Anatomy at Muhimbili and Herbert Kairuki Memorial Universities. The length of clavicle was measured by a vernier calliper; the middle point of this length was taken as the point where midclavicular circumference was measured with the help of a measuring thread and the angle of curvature of clavicle was measured by using protractors. The average lengths of the left and right clavicles were 15.23±1.12 cm and 15.43±1.01cm respectively. The average medial angle of curvature of left clavicle was 155.33° ± 4.39°and that of right clavicle was 153.40° ± 3.96°. The mean total angle of curvature of left clavicle was 293.54˚± 9.55°and the average total angle of curvature of right clavicle was 290.05±8.94°. The average midclavicular circumference of left clavicle was 3.88cm ± 0.33cm and that of right clavicle was 3.94cm±0.33cm. The right clavicle was longer than the left clavicle, the average medial angle of curvature of left clavicle was greater than medial angle of right clavicle, the average lateral angle of curvature of left clavicle was more than the average lateral angle of curvature of right clavicle and the mean of midclavicular circumference of right clavicle was greater than that of left clavicle.
Keywords: Morphometric, clavicle, curvatures, circumference 
Living with ghosts in Lorentz invariant theories
We argue that theories with ghosts may have a long lived vacuum state even if
all interactions are Lorentz preserving. In space-time dimension D = 2, we
consider the tree level decay rate of the vacuum into ghosts and ordinary
particles mediated by non-derivative interactions, showing that this is finite
and logarithmically growing in time. For D > 2, the decay rate is divergent
unless we assume that the interaction between ordinary matter and the ghost
sector is soft in the UV, so that it can be described in terms of non-local
form factors rather than point-like vertices. We provide an example of a
nonlocal gravitational-strength interaction between the two sectors, which
appears to satisfy all observational constraints.Comment: 17 pages, comments and references adde
Ferromagnetic properties of charged vector boson condensate
Bose-Einstein condensation of W bosons in the early universe is studied. It
is shown that, in the broken phase of the standard electroweak theory,
condensed W bosons form a ferromagnetic state with aligned spins. In this case
the primeval plasma may be spontaneously magnetized inside macroscopically
large domains and form magnetic fields which may be seeds for the observed
today galactic and intergalactic fields. However, in a modified theory, e.g. in
a theory without quartic self interactions of gauge bosons or for a smaller
value of the weak mixing angle, antiferromagnetic condensation is possible. In
the latter case W bosons form scalar condensate with macroscopically large
electric charge density i.e. with a large average value of the bilinear product
of W-vector fields but with microscopically small average value of the field
itself.Comment: Some numerical estimates and discussions are added according to the
referee's suggestions. This version is accepted for publication in JCA
Black hole variability and the star formation-active galactic nucleus connection : do all star-forming galaxies host an active galactic nucleus?
We investigate the effect of active galactic nucleus (AGN) variability on the observed connection between star formation and black hole accretion in extragalactic surveys. Recent studies have reported relatively weak correlations between observed AGN luminosities and the properties of AGN hosts, which has been interpreted to imply that there is no direct connection between AGN activity and star formation. However, AGNs may be expected to vary significantly on a wide range of timescales (from hours to Myr) that are far shorter than the typical timescale for star formation (gsim100 Myr). This variability can have important consequences for observed correlations. We present a simple model in which all star-forming galaxies host an AGN when averaged over ~100 Myr timescales, with long-term average AGN accretion rates that are perfectly correlated with the star formation rate (SFR). We show that reasonable prescriptions for AGN variability reproduce the observed weak correlations between SFR and L AGN in typical AGN host galaxies, as well as the general trends in the observed AGN luminosity functions, merger fractions, and measurements of the average AGN luminosity as a function of SFR. These results imply that there may be a tight connection between AGN activity and SFR over galaxy evolution timescales, and that the apparent similarities in rest-frame colors, merger rates, and clustering of AGNs compared to "inactive" galaxies may be due primarily to AGN variability. The results provide motivation for future deep, wide extragalactic surveys that can measure the distribution of AGN accretion rates as a function of SFR
Distribution of local density of states in disordered metallic samples: logarithmically normal asymptotics
Asymptotical behavior of the distribution function of local density of states
(LDOS) in disordered metallic samples is studied with making use of the
supersymmetric --model approach, in combination with the saddle--point
method. The LDOS distribution is found to have the logarithmically normal
asymptotics for quasi--1D and 2D sample geometry. In the case of a quasi--1D
sample, the result is confirmed by the exact solution. In 2D case a perfect
agreement with an earlier renormalization group calculation is found. In 3D the
found asymptotics is of somewhat different type: P(\rho)\sim
\exp(-\mbox{const}\,|\ln^3\rho|).Comment: REVTEX, 14 pages, no figure
Relic Backgrounds of Gravitational Waves from Cosmic Turbulence
Turbulence may have been produced in the early universe during several kind
of non-equilibrium processes. Periods of cosmic turbulence may have left a
detectable relic in the form of stochastic backgrounds of gravitational waves.
In this paper we derive general expressions for the power spectrum of the
expected signal. Extending previous works on the subject, we take into account
the effects of a continuous energy injection power and of magnetic fields. Both
effects lead to considerable deviations from the Kolmogorov turbulence
spectrum. We applied our results to determine the spectrum of gravity waves
which may have been produced by neutrino inhomogeneous diffusion and by a first
order phase transition. We show that in both cases the expected signal may be
in the sensitivity range of LISA.Comment: 25 pages, 1 figur
Leptogenesis from Pseudo-Scalar Driven Inflation
We examine recent claims for a considerable amount of leptogenesis, in some
inflationary scenarios, through the gravitational anomaly in the lepton number
current. We find that when the short distances contributions are properly
included the amount of lepton number generated is actually much smaller.Comment: JHEP style, 11 pages. Corrected typ
Non-Abelian Vortices, Super-Yang-Mills Theory and Spin(7)-Instantons
We consider a complex vector bundle E endowed with a connection A over the
eight-dimensional manifold R^2 x G/H, where G/H = SU(3)/U(1)xU(1) is a
homogeneous space provided with a never integrable almost complex structure and
a family of SU(3)-structures. We establish an equivalence between G-invariant
solutions A of the Spin(7)-instanton equations on R^2 x G/H and general
solutions of non-Abelian coupled vortex equations on R^2. These vortices are
BPS solitons in a d=4 gauge theory obtained from N=1 supersymmetric Yang-Mills
theory in ten dimensions compactified on the coset space G/H with an
SU(3)-structure. The novelty of the obtained vortex equations lies in the fact
that Higgs fields, defining morphisms of vector bundles over R^2, are not
holomorphic in the generic case. Finally, we introduce BPS vortex equations in
N=4 super Yang-Mills theory and show that they have the same feature.Comment: 14 pages; v2: typos fixed, published versio
Predictions from Quantum Cosmology
The world view suggested by quantum cosmology is that inflating universes
with all possible values of the fundamental constants are spontaneously created
out of nothing. I explore the consequences of the assumption that we are a
`typical' civilization living in this metauniverse. The conclusions include
inflation with an extremely flat potential and low thermalization temperature,
structure formation by topological defects, and an appreciable cosmological
constant.Comment: (revised version), 15 page
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