Racetrack inflation with matter fields and cosmic strings

We consider the coupling of racetrack inflation to matter fields as realized in the D3/D7 brane system. In particular, we investigate the possibility of cosmic string formation in this system. We find that strings can form before or at the onset of racetrack inflation is possible, but they are then inflated away. Furthermore, string formation at the end of inflation is prevented by the presence of the moduli sector. As a consequence, no strings survive racetrack inflation

A conserved metalloprotease mediates ecdysis in Caenorhabditis elegans

Molting is required for progression between larval stages in the life cycle of nematodes. We have identified four mutant alleles of a <i>Caenorhabditis elegans</i> metalloprotease gene, <i>nas-37</i>, that cause incomplete ecdysis. At each molt the cuticle fails to open sufficiently at the anterior end and the partially shed cuticle is dragged behind the animal. The gene is expressed in hypodermal cells 4 hours before ecdysis during all larval stages. The <i>NAS-37</i> protein accumulates in the anterior cuticle and is shed in the cuticle after ecdysis. This pattern of protein accumulation places NAS- 37 in the right place and at the right time to degrade the cuticle to facilitate ecdysis. The nas-37 gene has orthologs in other nematode species, including parasitic nematodes, and they undergo a similar shedding process. For example, <i>Haemonchus contortus</i> molts by digesting a ring of cuticle at the tip of the nose. Incubating <i>Haemonchus</i> larvae in extracted exsheathing fluids causes a refractile ring of digested cuticle to form at the tip of the nose. When <i>Haemonchus</i> cuticles are incubated with purified NAS-37, a similar refractile ring forms. NAS-37 degradation of the <i>Haemonchus</i> cuticle suggests that the metalloproteases and the cuticle substrates involved in exsheathment of parasitic nematodes are conserved in free-living nematodes

Cosmic D-Strings and Vortons in Supergravity

Recent developments in string inspired models of inflation suggest that D-strings are formed at the end of inflation. Within the supergravity model of D-strings there are 2(n-1) chiral fermion zero modes for a D-string of winding n. Using the bounds on the relic vorton density, we show that D-strings with winding number n>1 are more strongly constrained than cosmic strings arising in cosmological phase transitions. The D-string tension of such vortons, if they survive until the present, has to satisfy 8\pi G_N \mu \lesssim p 10^{-26} where p is the intercommutation probability. Similarly, D-strings coupled with spectator fermions carry currents and also need to respect the above bound. D-strings with n=1 do not carry currents and evade the bound. We discuss the coupling of D-strings to supersymmetry breaking. When a single U(1) gauge group is present, we show that there is an incompatibility between spontaneous supersymmetry breaking and cosmic D-strings. We propose an alternative mechanism for supersymmetry breaking, which includes an additional U(1), and might alleviate the problem. We conjecture what effect this would have on the fermion zero modes.Comment: 11 page

Global Strings and the Aharonov-Bohm Effect

When a fermion interacts with a global vortex or cosmic string a solenoidal "gauge" field is induced. This results in a non-trivial scattering cross-section. For scalars and non-relativistic fermions the cross-section is similar to that of Aharonov and Bohm, but with corrections. A cosmological example is compared to one in liquid He$^{3}$-A and important differences are discovered.Comment: 11 pages, DAMTP 93-5

Mass of a quantum 't Hooft-Polyakov monopole

The quantum mechanical mass of 't Hooft-Polyakov monopoles in the four-dimensional Georgi-Glashow is calculated non-perturbatively using lattice Monte Carlo simulations. This is done by imposing twisted boundary conditions that ensure there is one unit of magnetic charge on the lattice, and measuring the free energy difference between this ensemble and the vacuum. In the weak-coupling limit, the results can be used to determine the quantum correction to the classical mass, once renormalisation of couplings is taken properly into account. The methods can also be used to study the masses at strong coupling, i.e., near the critical point, where there are hints of a possible electric-magnetic duality.Comment: 17 pages, 4 figures. Typos corrected, one reference adde

Proposing the Communicate Bond Belong Theory: Evolutionary intersections with episodic interpersonal communication

The Communicate Bond Belong (CBB) Theory is an evolutionary and motivational explanation of human communication’s role in the relational functions of social interaction. CBB Theory conceives of all social interactions as energy expending, but posits that only some social interactions are striving behaviors (i.e., actions taken to satiate a need). CBB Theory proposes that social interaction operates within a homeostatic system, developed from internal pressures to satiate a need to belong, shaped by competing desires to invest and conserve social energy, and adaptable to new social circumstances and technological affordances. The theory bridges gaps among evolutionary and social psychology theories and interpersonal communication theories by attending to the multifunctional nature of everyday talk in relation to fundamental human needs

Noise Pollution in the Operating Room

Introduction: Noise pollution in the operating room (OR) poses a threat to both patients and providers. Sound levels often exceed recommended standards set forth by the National Institute for Occupational Safety and Health (NIOSH) and the Occupational Safety and Health Administration (OSHA). The purpose of this project was to examine current evidence and implement education for student registered nurse anesthetists (SRNAs) regarding noise pollution in the OR. The education module emphasized the effect of increased noise levels on the delivery of an anesthetic, with a focus on resultant sequelae. Methods: A literature review produced 117 articles, of which thirty-five were included for analysis. Systematic reviews, randomized and non-randomized control trials, cohort studies, case studies, qualitative studies and expert opinion were all considered. A research based education module was delivered to SRNAs. A pre-test and post-test methodology was utilized to assess the efficacy of the education module for SRNAs. Analysis of Results: Results generated from the education module illustrate a knowledge deficient of student registered nurse anesthetists pertaining to noise reduction, cognitive demand, and attention allocation. Post-test scores (M=90%) for SRNAs who completed the education module were significantly greater than pre-test scores (M=60%).  t(39)= 10.1, p = 1.88 x 10-12. Recommendations for Practice: Noise pollution is a complex, multifactorial problem. The physical, psychological and emotional effects of noise pollution are the inability to critically think, impaired team communication, chronic hearing loss, increased incidence of cardiovascular disease, and medical error. Emphasis placed on sustaining and integrating noise reduction education into curriculum schemas of nurse anesthesia programs is prudent. Educational content delivered to all anesthesia providers and the interdisciplinary care team in the operating room would be a comprehensive plan. Although several national initiatives are in place to reduce noise, it is imperative that knowledge is shared and interventions implemented to protect both provider and patient. Furthermore, there should be a collaboration amongst a variety of surgical specialties to continue research pertaining to the production of noise in the operating room. Keywords: Anesthesia, Noise, Noise pollution, Operating room, Occupational safet

First Measurements of Surface Nuclear Magnetic Resonance Signals in a Grounded Bipole

Surface nuclear magnetic resonance (surface NMR) soundings are geophysical techniques that offer direct detection of groundwater. Ordinary surface NMR soundings are achieved with a wire loop that acts as both transmitter and receiver. We extend the capability of the technique by using a grounded electrical bipole as the measurement sensor. We provide the first successful measurements of surface NMR signals taken with a grounded electrode pair on a beach outside Perth, Western Australia. Simple changes to existing equations are sufficient to provide forward models for the changes in measurement technique, and the resulting groundwater models are consistent with coincident loop soundings. Our result opens the field for novel sounding techniques of surface NMR signals that could have broad impact on near-surface groundwater investigations

Fermionic Zero Modes of Supergravity Cosmic Strings

Recent developments in string theory suggest that cosmic strings could be formed at the end of brane inflation. Supergravity provides a realistic model to study the properties of strings arising in brane inflation. Whilst the properties of cosmic strings in flat space-time have been extensively studied there are significant complications in the presence of gravity. We study the effects of gravitation on cosmic strings arising in supergravity. Fermion zero modes are a common feature of cosmic strings, and generically occur in supersymmetric models. The corresponding massless currents can give rise to stable string loops (vortons). The vorton density in our universe is strongly constrained, allowing many theories with cosmic strings to be ruled out. We investigate the existence of fermion zero modes on cosmic strings in supergravity theories. A general index theorem for the number of zero modes is derived. We show that by including the gravitino, some (but not all) zero modes disappear. This weakens the constraints on cosmic string models. In particular, winding number one cosmic D-strings in models of brane inflation are not subject to vorton constraints. We also discuss the effects of supersymmetry breaking on cosmic D-strings.Comment: 33 page

Constraints on holographic multifield inflation and models based on the Hamilton-Jacobi formalism

In holographic inflation, the 4D cosmological dynamics is postulated to be dual to the renormalization group flow of a 3D Euclidean conformal field theory with marginally relevant operators. The scalar potential of the 4D theory—in which inflation is realized—is highly constrained, with use of the Hamilton–Jacobi equations. In multifield holographic realizations of inflation, fields additional to the inflaton cannot display underdamped oscillations (that is, their wave functions contain no oscillatory phases independent of the momenta). We show that this result is exact, independent of the number of fields, the field space geometry, and the shape of the inflationary trajectory followed in multifield space. In the specific case where the multifield trajectory is a straight line or confined to a plane, it can be understood as the existence of an upper bound on the dynamical masses m of extra fields of the form m≤3H/2 up to slow roll corrections. This bound corresponds to the analytic continuation of the well-known Breitenlohner–Freedman bound found in anti–de Sitter spacetimes in the case when the masses are approximately constant. The absence of underdamped oscillations implies that a detection of “cosmological collider” oscillatory patterns in the non-Gaussian bispectrum would not only rule out single-field inflation, but also holographic inflation or any inflationary model based on the Hamilton–Jacobi equations. Hence, future observations have the potential to exclude, at once, an entire class of inflationary theories, regardless of the details involved in their model building.Article / Letter to editorLeiden Instituut Onderzoek NatuurkundeUniversity of Chil