Screening and the quantitative π-model description of the optical spectra and polarizations of phenyl based oligomers

The long standing problem of the inability of many semiempirical models to correctly predict the polarization of the higher dipole allowed optical transitions of phenyl based π-conjugated polymers and molecules is examined and related to the issue of internal and external screening of π-π electron Coulomb interactions within the molecules. Following a review of previous theoretical and experimental work, π electron only the Complete Neglect of Differential Overlap (CNDO) model is presented which, for the first time, is able to predict accurately the energies and symmetries of all the observed optical transitions of benzene, biphenyl and trans -stilbene, up to ~8-10 eV. In so doing, it is demonstrated that the problem with previous calculations was the noninclusion of screening from outside the p electron system itself. By fitting separately the spectra in hydrocarbon based condensed phases, in the gas phase and in solid rare gas matrices, and comparing the resulting model parameters, we show that, while the effects of screening from the environment are certainly noticeable, the most important spectral features - in particular the ordering of dipole allowed transitions - come from effective screening by the s electrons. We find that both of these effects can be adequately accounted for within a π electron only model by using a dielectric constant and appropriate parameter renormalization

Creating spaces: testimonio, impossible knowledge, and academe

Postprint upload.This article examines what it means to engage seriously with speech and writing events, such as testimonio, articulated by people whose theoretical base lies primarily in experience outside the walls of academe. I argue that we dismiss such unfamiliar scholarship to the detriment of all involved. If we are truly committed to learning, then we must expose ourselves to language forms and cultural norms that are different from those with which we are familiar. We must learn from them how to acknowledge the limits of our analysis and how to find “impossible knowledge” in unaccustomed places

Interferometric Observatories in Earth Orbit

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/76217/1/AIAA-1728-623.pd

Maximal care considerations when treating patients with end-stage heart failure: ethical and procedural quandaries in management of the very sick

Deciding who should receive maximal technological treatment options and who should not represents an ethical, moral, psychological and medico-legal challenge for health care providers. Especially in patients with chronic heart failure, the ethical and medico-legal issues associated with providing maximal possible care or withholding the same are coming to the forefront. Procedures, such as cardiac transplantation, have strict criteria for adequate candidacy. These criteria for subsequent listing are based on clinical outcome data but also reflect the reality of organ shortage. Lack of compliance and non-adherence to lifestyle changes represent relative contraindications to heart transplant candidacy. Mechanical circulatory support therapy using ventricular assist devices is becoming a more prominent therapeutic option for patients with end-stage heart failure who are not candidates for transplantation, which also requires strict criteria to enable beneficial outcome for the patient. Physicians need to critically reflect that in many cases, the patient’s best interest might not always mean pursuing maximal technological options available. This article reflects on the multitude of critical issues that health care providers have to face while caring for patients with end-stage heart failure

The 'lost child' as figure of trauma and recovery in early post-war cinema: Fred Zinnemann's The Search (1948) and Natan Gross's Unzere Kinder (1948)

The article examines the figure of the ‘lost child’ in feature films of the immediate post-war period. The figure’s enormous symbolic value as innocent victim and future generation, granted the ‘lost child’ a key position in post-war discourse, including films which tried to grapple with the moral and physical destruction of the continent after 1945. National film industries, particularly of the perpetrator nation, employed the ‘lost child’ for genre stories in which the post-war chaos is being mastered and a new, masculine national self is re-built. However, films made by victim groups outside a national context rely on the ‘lost child’ to broach the destruction of their identity by war and persecution. Analysing two films, Fred Zinnemann’s The Search (1948) and Nata Gross’s Unzere Kinder (1948), I argue that they use the child figure to deal with traumatization and make it part of the reconstruction of communal intergenerational relations. This does not result in stories of masculine mastery but in narratives that incorporate moments of trauma process emerging around destroyed mother-child relations. The films, encoding traumatization in film language, develop a rich cinematic language along questions of identity and form a first instance of posttraumatic cinema

Emergent Properties of Patch Shapes Affect Edge Permeability to Animals

Animal travel between habitat patches affects populations, communities and ecosystems. There are three levels of organization of edge properties, and each of these can affect animals. At the lowest level are the different habitats on each side of an edge, then there is the edge itself, and finally, at the highest level of organization, is the geometry or structure of the edge. This study used computer simulations to (1) find out whether effects of edge shapes on animal behavior can arise as emergent properties solely due to reactions to edges in general, without the animals reacting to the shapes of the edges, and to (2) generate predictions to allow field and experimental studies to test mechanisms of edge shape response. Individual animals were modeled traveling inside a habitat patch that had different kinds of edge shapes (convex, concave and straight). When animals responded edges of patches, this created an emergent property of responding to the shape of the edge. The response was mostly to absolute width of the shapes, and not the narrowness of them. When animals were attracted to edges, then they tended to collect in convexities and disperse from concavities, and the opposite happened when animals avoided edges. Most of the responses occurred within a distance of 40% of the perceptual range from the tip of the shapes. Predictions were produced for directionality at various locations and combinations of treatments, to be used for testing edge behavior mechanisms. These results suggest that edge shapes tend to either concentrate or disperse animals, simply because the animals are either attracted to or avoid edges, with an effect as great as 3 times the normal density. Thus edge shape could affect processes like pollination, seed predation and dispersal and predator abundance

Effects of steroids and angiotensin converting enzyme inhibition on circumferential strain in boys with Duchenne muscular dystrophy: a cross-sectional and longitudinal study utilizing cardiovascular magnetic resonance

<p>Abstract</p> <p>Background</p> <p>Steroid use has prolonged ambulation in Duchenne muscular dystrophy (DMD) and combined with advances in respiratory care overall management has improved such that cardiac manifestations have become the major cause of death. Unfortunately, there is no consensus for DMD-associated cardiac disease management. Our purpose was to assess effects of steroid use alone or in combination with angiotensin converting enzyme inhibitors (ACEI) or angiotension receptor blocker (ARB) on cardiovascular magnetic resonance (CMR) derived circumferential strain (ε_cc).</p> <p>Methods</p> <p>We used CMR to assess effects of corticosteroids alone (Group A) or in combination with ACEI or ARB (Group B) on heart rate (HR), left ventricular ejection fraction (LVEF), mass (LVM), end diastolic volume (LVEDV) and circumferential strain (ε_cc) in a cohort of 171 DMD patients >5 years of age. Treatment decisions were made independently by physicians at both our institution and referral centers and not based on CMR results.</p> <p>Results</p> <p>Patients in Group A (114 studies) were younger than those in Group B (92 studies)(10 ± 2.4 vs. 12.4 ± 3.2 years, p < 0.0001), but HR, LVEF, LVEDV and LVM were not different. Although ε_ccmagnitude was lower in Group B than Group A (-13.8 ± 1.9 vs. -12.8 ± 2.0, p = 0.0004), age correction using covariance analysis eliminated this effect. In a subset of patients who underwent serial CMR exams with an inter-study time of ~15 months, ε_ccworsened regardless of treatment group.</p> <p>Conclusions</p> <p>These results support the need for prospective clinical trials to identify more effective treatment regimens for DMD associated cardiac disease.</p