Numerical modeling of the multi-stage Stern\unicode{x2013}Gerlach experiment by Frisch and Segr\`e using co-quantum dynamics via the Bloch equation

We numerically study the spin flip in the Frisch\unicode{x2013}Segr\`e experiment, the first multi-stage Stern\unicode{x2013}Gerlach experiment, within the context of the novel co-quantum dynamics theory. We model the middle stage responsible for spin rotation by sampling the atoms with the Monte Carlo method and solving the dynamics of the electron and nuclear magnetic moments numerically according to the Bloch equation. Our results show that, without using any fitting parameters, the co-quantum dynamics closely reproduces the experimental observation reported by Frisch and Segr\`e in 1933, which has so far lacked theoretical predictions.Comment: 9 pages, 6 figure

Numerical modeling of the multi-stage Stern\unicode{x2013}Gerlach experiment by Frisch and Segr\`e using co-quantum dynamics via the Schr\"odinger equation

We use a theory termed co-quantum dynamics (CQD) to numerically model spin flip in the multi-stage Stern\unicode{x2013}Gerlach (SG) experiment conducted by R. Frisch and E. Segr\`e. This experiment consists of two Stern\unicode{x2013}Gerlach apparatuses separated by an inner rotation chamber that varies the fraction of spin flip. To this day, quantum mechanical treatments inadequately predict the Frisch\unicode{x2013}Segr\`e experiment. Here, we account for electron-nuclear interactions according to CQD and solve the associated Schr\"odinger equation. Our simulation outcome agrees with the Frisch\unicode{x2013}Segr\`e experimental observation and supports CQD as a potential model for electron spin evolution and collapse.Comment: 13 pages, 3 figure

Quantum imaging of biological organisms through spatial and polarization entanglement

Quantum imaging can potentially provide certain advantages over classical imaging. Thus far, however, the signal-to-noise ratios (SNRs) are poor; the resolvable pixel counts are low; biological organisms have not been imaged; birefringence has not been quantified. Here, we introduce quantum imaging by coincidence from entanglement (ICE). Utilizing spatially and polarization entangled photon pairs, ICE exhibits higher SNRs, greater resolvable pixel counts, imaging of biological organisms, and ghost birefringence quantification; it also enables 25 times greater suppression of stray light than classical imaging. ICE can potentially empower quantum imaging towards new applications in life sciences and remote sensing.Comment: 57 pages, 4 figures, 18 supplementary figures, 7 supplementary notes, 1 supplementary tabl

Deletion of the Complement C5a Receptor Alleviates the Severity of Acute Pneumococcal Otitis Media following Influenza A Virus Infection in Mice

There is considerable evidence that influenza A virus (IAV) promotes adherence, colonization, and superinfection by S. pneumoniae (Spn) and contributes to the pathogenesis of otitis media (OM). The complement system is a critical innate immune defense against both pathogens. To assess the role of the complement system in the host defense and the pathogenesis of acute pneumococcal OM following IAV infection, we employed a well-established transtympanically-induced mouse model of acute pneumococcal OM. We found that antecedent IAV infection enhanced the severity of acute pneumococcal OM. Mice deficient in complement C1qa (C1qa−/−) or factor B (Bf −/−) exhibited delayed viral and bacterial clearance from the middle ear and developed significant mucosal damage in the eustachian tube and middle ear. This indicates that both the classical and alternative complement pathways are critical for the oto-immune defense against acute pneumococcal OM following influenza infection. We also found that Spn increased complement activation following IAV infection. This was characterized by sustained increased levels of anaphylatoxins C3a and C5a in serum and middle ear lavage samples. In contrast, mice deficient in the complement C5a receptor (C5aR) demonstrated enhanced bacterial clearance and reduced severity of OM. Our data support the concept that C5a-C5aR interactions play a significant role in the pathogenesis of acute pneumococcal OM following IAV infection. It is possible that targeting the C5a-C5aR axis might prove useful in attenuating acute pneumococcal OM in patients with influenza infection

Agency, firm growth, and managerial turnover

We study the relation between firm growth and managerial incentive provision under moral hazard when a long-lived firm is operated by a sequence of managers. In our model, firms replace their managers not only upon poor performance to provide incentives, but also when outside managers are at a comparative advantage to lead the firm through a new growth phase. We show how the optimal contract can be implemented with a system of deferred compensation credit and bonuses, along with dismissal and severance policies. Firms with better investment prospects have higher managerial turnover and rely on more front-loaded compensation schemes. Growth-induced turnover can result in positive severance if the principal needs to incentivize the manager to truthfully report the arrival of a growth opportunity. Realized firm growth depends jointly on the exogenous arrival of growth opportunities and the severity of the moral hazard problem. We also find a new component of agency costs due to the spillover effect of the tenure of the incumbent manager onto the present value of future managers’ compensation

Model simulations of the Bay of Fundy Gyre : 2. Hindcasts for 2005–2007 reveal interannual variability in retentiveness

Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C09005, doi:10.1029/2008JC004948.A persistent gyre at the mouth of the Bay of Fundy results from a combination of tidal rectification and buoyancy forcing. Here we assess recent interannual variability in the strength of the gyre using data assimilative model simulations. Realistic hindcast representations of the gyre are considered during cruises in 2005, 2006, and 2007. Assimilation of shipboard and moored acoustic Doppler current profiler velocities is used to improve the skill of the simulations, as quantified by comparison with nonassimilated drifter trajectories. Our hindcasts suggest a weakening of the gyre system during May 2005. Retention of simulated passive particles in the gyre during that period was highly reduced. A recovery of the dense water pool in the deep part of the basin by June 2006 resulted in a return to particle retention characteristics similar to climatology. Retention estimates reached a maximum during May 2007 (subsurface) and June–July 2007 (near surface). Interannual variability in the strength of the gyre was primarily modulated by the stratification of the dense water pool inside the Grand Manan Basin. These changes in stratification were associated with mixing conditions the preceding fall–winter and/or advectively driven modification of water mass properties.The preparation of this paper was supported by NSF grant OCE-0430724, NIEHS grant 1P50-ES01274201 (Woods Hole Center for Oceans and Human Health), andNOAAgrant NA06NOS4780245 (GOMTOX). Additional support was provided by NSF grant DMS-0417769

Model simulations of the Bay of Fundy Gyre : 1. Climatological results

Author Posting. © American Geophysical Union, 2008. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 113 (2008): C10027, doi:10.1029/2007JC004480.The characteristics of a persistent gyre in the mouth of the Bay of Fundy are studied using model simulations. A set of climatological runs are conducted to evaluate the relative importance of the different forcing mechanisms affecting the gyre. The main mechanisms are tidal rectification and density-driven circulation. Stronger circulation of the gyre occurs during the later part of the stratified season (July–August and September–October). The density-driven flow around the gyre is set up by weak tidal mixing in the deep basin in the central Bay of Fundy and strong tidal mixing on the shallow flanks around Grand Manan Island and western Nova Scotia. Spring river discharge has an important influence on near-surface circulation but only a small effect when averaged over the entire water column. Retention of particles in the gyre is controlled by the residual tidal circulation, increased frontal retention during stratified periods, wind stress, and interactions with the adjacent circulation of the Gulf of Maine. Residence times longer than 30 days are predicted for particles released in the proximity of the gyre.The preparation of this paper was supported by NSF grant OCE-0430724 and NIEHS grant 1P50-ES01274201 (Woods Hole Center for Oceans and Human Health) and NOAA grant NA06NOS4780245 (GOMTOX). Additional support was provided by NSF grant DMS-0417769

Triplet Dispersion in CuGeO_3: Perturbative Analysis

We reconsider the 2d model for CuGeO_3 introduced previously (Phys. Rev. Lett. 79, 163 (1997)). Using a computer aided perturbation method based on flow equations we expand the 1-triplet dispersion up to 10th order. The expansion is provided as a polynom in the model parameters. The latter are fixed by fitting the theoretical result to experimental data obtained by INS. For a dimerization delta = 0.08(1) we find an excellent agreement with experiment. This value is at least 2 to 3 times higher than values deduced previously from 1d chain approaches. For the intrachain frustration alpha_0 we find a smaller value of 0.25(3). The existence of interchain frustration conjectured previously is confirmed by the analysis of temperature dependent susceptibility.Comment: 8 pages, 10 figures, submitted to Phys. Rev.

Sudden massive neck swelling due to hemorrhage of a thyroid adenoma: a case report

<p>Abstract</p> <p>Introduction</p> <p>Sudden swelling of the neck is an emergency situation that can be life-threatening for the patient. Therefore, an understanding of the possible underlying pathology is of great importance. Sudden massive swelling of the neck because of intralesional bleeding of a thyroid adenoma is seldom encountered but must be considered. Such massive swelling caused by spontaneous bleeding of a thyroid adenoma has not yet been described in the literature.</p> <p>Case presentation</p> <p>We report the case of a 71-year-old Caucasian man with sudden massive neck swelling due to intralesional bleeding of a thyroid adenoma. We present his clinical history, physical examination results, computed tomography (CT) scans, and histological findings after surgery. He presented with sudden massive swelling of the left side of his neck after sneezing while working with his hands over his head. An ear, nose, and throat examination showed a painless swelling of the left side of his neck and a displacement of his larynx to the right. CT scans revealed a mass originating from the left lobe of his thyroid gland and the mass displaced his larynx and trachea. A surgical exploration showed a greatly enlarged left lobe of his thyroid gland. A histopathological examination showed a hemorrhagic infarction of a follicular thyroid adenoma.</p> <p>Conclusions</p> <p>Sudden intralesional bleeding of a thyroid adenoma is a rare condition but one that should be considered in cases of sudden and massive swelling of the neck.</p