The Experience of Traumatic Stress among Urban Firefighters

Findings provide evidence that it is possible for emergency responders to become ‘locked into’ a regular cycle of trauma exposure that includes rapid returns to operationally ready status (i.e. being made available for another turnout immediately, or soon after returning from a previous emergency situation). Without the opportunity to interrupt the emotional reaction of an earlier traumatic response, a downward spiral of inescapable stress response may be instigated and with ongoing exposure. This paper details evidence suggesting the existence of a relationship between the work tasks of the fire fighters and a propensity for certain physiological responses and stress reactions noted during on-the-job research. Sensitivity to such processes may be gradually built up among emergency responders as their career progresses. The work suggests that in addition to instances of critical incident stress, that could be expected among emergency workers, the turn-out mechanism used actually pre-disposes the fire fighters to ongoing traumatic responses

Remarks on the Cosmological Constant

The acceleration of the surface of last scatter (SLS) must somehow reflect the energy content within it. A test particle at the SLS is assumed to experience a linear combination of two forces: one Newtonian, the other pseudo-Newtonian describable by a cosmological constant ${\Lambda}$ in general relativity. In the ${\Lambda}$ description, which is surely too unimaginative, the size of ${\Lambda}$ reflects only the comparable magnitudes of the Newtonian and pseudo-Newtonian forces; any claim of fine tuning due to quantum mechanics is probably illusory.Comment: 6 pages, no figures; improved versio

Modeling Autistic Features in Animals

A variety of features of autism can be simulated in rodents, including the core behavioral hallmarks of stereotyped and repetitive behaviors, and deficits in social interaction and communication. Other behaviors frequently found in autism spectrum disorders (ASDs) such as neophobia, enhanced anxiety, abnormal pain sensitivity and eye blink conditioning, disturbed sleep patterns, seizures, and deficits in sensorimotor gating are also present in some of the animal models. Neuropathology and some characteristic neurochemical changes that are frequently seen in autism, and alterations in the immune status in the brain and periphery are also found in some of the models. Several known environmental risk factors for autism have been successfully established in rodents, including maternal infection and maternal valproate administration. Also under investigation are a number of mouse models based on genetic variants associated with autism or on syndromic disorders with autistic features. This review briefly summarizes recent developments in this field, highlighting models with face and/or construct validity, and noting the potential for investigation of pathogenesis, and early progress toward clinical testing of potential therapeutics. Wherever possible, reference is made to reviews rather than to primary articles

Dark Energy from Strings

A long-standing problem of theoretical physics is the exceptionally small value of the cosmological constant $\Lambda \sim 10^{-120}$ measured in natural Planckian units. Here we derive this tiny number from a toroidal string cosmology based on closed strings. In this picture the dark energy arises from the correlation between momentum and winding modes that for short distances has an exponential fall-off with increasing values of the momenta. The freeze-out by the expansion of the background universe for these transplanckian modes may be interpreted as a frozen condensate of the closed-string modes in the three non-compactified spatial dimensions.Comment: 10 pages LaTeX. Talk at Coral Gables Conference, December 12-16, 200

String Theory and Unification

The use of the AdS/CFT correspondence to arrive at quiver gauge field theories is discussed. An abelian orbifold with the finite group $Z_{p}$ can give rise to a nonsupersymmetric $G = U(N)^p$ gauge theory with chiral fermions and complex scalars in different bi-fundamental representations of $G$. The precision measurements at the $Z$ resonance suggest the values $p = 12$ and $N = 3$, and a unifications scale $M_U \sim 4$ TeV. Dedicated to the 65th birthday of Pran Nath.Comment: 11 pages, 2 figures, talk at PASCOS 2004 / Nath Fes