Some Observations on the Shore Fauna of Baffin Island

A study of shore animals made in the summer 1953, covering Frobisher Bay, Cumberland Sound and Padloping Island. Thirty species of invertebrates and four of fishes are recorded from the area; their habitat and distribution are described and compared with those in Greenland. A detailed itinerary and review of earlier work precede the account

Observations on the Distribution and Ecology of Some Arctic Fish

Reports on work during 1953-1955, mostly in the Coppermine River and delta of Mackenzie District, but extending east to Frobisher Bay, Baffin Island. The 27 species collected and two others observed are listed with notes on their distribution, ecology, and on the taxonomy when specific identification is uncertain. The number of specimens collected, dates, localities, and habitat are cited for each species. Methods are stated

Leptogenesis in the Light of Super-Kamiokande Data and a Realistic String Model

We discuss leptogenesis in the light of indications of neutrino masses and mixings from Super-Kamiokande and other data on atmospheric neutrinos, as well as the solar neutrino deficit. Neutrino masses and mixings consistent with these data may produce in a natural and generic way a lepton asymmetry that is suffient to provide the observed baryon asymmetry, after processing via non-perturbative electroweak effects. We illustrate this discussion in the framework of the string-derived flipped SU(5) model, using particle assignments and choices of vacuum parameters that are known to give realistic masses to quarks and charged leptons. We display one scenario for neutrino masses that also accommodates leptogenesis.Comment: 18 pages, 1 figur

Arctic and Subarctic Examples of Intertidal Zonation

Analysis based on extensive observations of shores on Baffin Island, at Coppermine, and other localities on the north mainland coast and arctic islands of Canada. Populations on rocky shores were found to exist only where shore ice was thinner than tidal amplitude; in the Arctic proper, they are rare and limited to low levels as exemplified from Coronation Gulf - Boothia Peninsula, Admiralty Inlet, etc. In the sub-Arctic they have a mid-littoral zone dominated by Balanus balanoides and fucoids, bordered by infralittoral and supralittoral fringes. Sedimentary shores in the subarctic localities showed dense populations only near low-water level; in the Arctic they are almost barren

Light-Cone Broadening and TeV Scale Extra Dimensions

We examine the effect of light-cone broadening induced by quantum-gravity foam in the context of theories with ``large'' extra dimensions stretching between two parallel brane worlds. We consider the propagation of photon probes on one of the branes, including the response to graviton fluctuations, from both field- and string-theoretical viewpoints. In the latter approach, the dominant source of light-cone broadening may be the recoil of the D-brane, which scales linearly with the string coupling. Astrophysical constraints then place strong restrictions on consistent string models of macroscopic extra dimensions. The broadening we find in the field-theoretical picture seems to be close to the current sensitivity of gravity-wave interferometers, and therefore could perhaps be tested experimentally in the foreseeable future.Comment: 12 pages REVTeX, 2 axodraw figures incorporate

Lower Limits on Soft Supersymmetry-Breaking Scalar Masses

Working in the context of the CMSSM, we argue that phenomenological constraints now require the universal soft supersymmetry-breaking scalar mass m_0 be non-zero at the input GUT scale. This conclusion is primarily imposed by the LEP lower limit on the Higgs mass and the requirement that the lightest supersymmetric particle not be charged. We find that m_0 > 0 for all tan beta if mu 0 only when tan beta sim 8 and one allows an uncertainty of 3+ GeV in the theoretical calculation of the Higgs mass. Upper limits on flavour-changing neutral interactions in the MSSM squark sector allow substantial violations of non-universality in the m_0 values, even if their magnitudes are comparable to the lower limit we find in the CMSSM. Also, we show that our lower limit on m_0 at the GUT scale in the CMSSM is compatible with the no-scale boundary condition m_0 = 0 at the Planck scale.Comment: 11 pages, latex, 6 eps figure

Vanishing Str M^2 in the presence of anomalous U_A(1)

We show that the presence of an anomalous $\rm U_A(1)$ factor in the gauge group of string-derived models may have the new and important phenomenological consequence of allowing the vanishing of ${\rm Str}\,{\cal M}^2$ in the ``shifted" vacuum, that results in the process of cancelling the anomalous $\rm U_A(1)$. The feasibility of this effect seems to be enhanced by a vanishing vacuum energy, and by a ``small" value of ${\rm Str}\,{\cal M}^2$ in the original vacuum. In the class of free-fermionic models with vanishing vacuum energy that we focus on, a necessary condition for this mechanism to be effective is that ${\rm Str}\,{\cal M}^2>0$ in the original vacuum. A vanishing ${\rm Str}\,{\cal M}^2$ ameliorates the cosmological constant problem and is a necessary element in the stability of the no-scale mechanism.Comment: 7 pages, no figures, LaTe

Derivation of a Vacuum Refractive Index in a Stringy Space-Time Foam Model

It has been suggested that energetic photons propagating in vacuo should experience a non-trivial refractive index due to the foamy structure of space-time induced by quantum-gravitational fluctuations. The sensitivity of recent astrophysical observations, particularly of AGN Mk501 by the MAGIC Collaboration, approaches the Planck scale for a refractive index depending linearly on the photon energy. We present here a new derivation of this quantum-gravitational vacuum refraction index, based on a stringy analogue of the interaction of a photon with internal degrees of freedom in a conventional medium. We model the space-time foam as a gas of D-particles in the bulk space-time of a higher-dimensional cosmology where the observable Universe is a D3-brane. The interaction of an open string representing a photon with a D-particle stretches and excites the string, which subsequently decays and re-emits the photon with a time delay that increases linearly with the photon energy and is related to stringy uncertainty principles. We relate this derivation to other descriptions of the quantum-gravitational refractive index in vacuo.Comment: 8 pages, 3 eps figure

Constraints From Gauge Coupling Unification On The Scale Of Supersymmetry Breaking

We reanalyze precision LEP data and coupling constant unification in the minimal supersymmetric $SU(5)$ model including the evolution of the gaugino masses. We derive general bounds on the primordial gaugino supersymmetry-breaking mass-scale $m_{1/2}$ in terms of the various input parameters. The model cannot accommodate m_{1/2}<1\TeV for values of \as < 0.115, even for extreme $1-\sigma$ values of the other inputs. We emphasize the sensitivity of this type of calculations to the various input parameters.Comment: 9 pages, 1 figure not included, ACT-10/9

Flat Directions in Flipped SU(5) I: All-Order Analysis

We present a systematic classification of field directions for the string-derived flipped SU(5) model that are D- and F-flat to all orders. Properties of the flipped SU(5) model with field values in these directions are compared to those associated with other flat directions that have been shown to be F-flat to specific finite orders in the superpotential. We discuss the phenomenological Higgs spectrum, and quark and charged-lepton mass textures.Comment: 22 pages. Late