Bichromatically driven double well: parametric perspective of the strong-field control landscape reveals the influence of chaotic states

The aim of this work is to understand the influence of chaotic states in control problems involving strong fields. Towards this end, we numerically construct and study the strong field control landscape of a bichromatically driven double well. A novel measure based on correlating the overlap intensities between Floquet states and an initial phase space coherent state with the parametric motion of the quasienergies is used to construct and interpret the landscape features. "Walls" of no control, robust under variations of the relative phase between the fields, are seen on the control landscape and associated with multilevel interactions involving chaotic Floquet states.Comment: 9 pages and 6 figures. Rewritten and expanded version of arXiv:0707.4547 [nlin.CD]. Accepted for publication in J. Chem. Phys. (2008

Intramolecular vibrational energy redistribution as state space diffusion: Classical-quantum correspondence

We study the intramolecular vibrational energy redistribution (IVR) dynamics of an effective spectroscopic Hamiltonian describing the four coupled high frequency modes of CDBrClF. The IVR dynamics ensuing from nearly isoenergetic zeroth-order states, an edge (overtone) and an interior (combination) state, is studied from a state space diffusion perspective. A wavelet based time-frequency analysis reveals an inhomogeneous phase space due to the trapping of classical trajectories. Consequently the interior state has a smaller effective IVR dimension as compared to the edge state.Comment: 5 pages, 3 figure

Diagnostic utility of fecal calprotectin as a biomarker of gut inflammation in neonates to predict necrotizing enterocolitis: A prospective study

Background: Necrotizing enterocolitis (NEC) is a neonatal emergency that affects preterm newborns during the 1st weeks of life.Diagnosis is made mainly by clinical criteria since no specific diagnostic tests are available. Objective: The objective was to evaluatefecal calprotectin (fCal) as a biomarker of gut inflammation to predict NEC in preterm neonates. Methods: Design: Diagnostic testevaluation. Inclusion criteria: 102 preterm neonates <36 weeks gestation and within 7 days of birth admitted in Level III neonatalintensive care unit (NICU) were recruited from January 2010 to May 2011. Exclusion criteria: Congenital anomalies and overt infection.Paired stool samples at day 3 and 7 were analyzed by lateral quantum blue rapid calprotectin assay. Cut-off values of fCal weredetermined among 30 term healthy infants. A structured questionnaire which included gestational age, symptoms at admission, andmodified Bell’s staging was used to record NEC episodes on day 3 and 7 of admission. Septic screen and radiological tools were doneas per NICU protocol. Results: 48% were above 34 weeks gestation; 31.3% were of very low birth weight. As per modified Bell’sstaging on day 3 and 7, 22 and 11 neonates had 1a or above stage, respectively. 15 had features of NEC; of these, 12 were managedappropriately and discharged and 3 died. In the receiver-operated curve with fCal >279 μg/g as cutoff, the area under the curve was0.652 (95% confidence interval: 0.516-0.789). Day 3 fCal levels were high in 65.7% neonates. Using NEC as outcome, sensitivity of thetest was 93.3%; specificity was 39%; positive predictive value was 20.8% and negative predictive value was 97.14%. Conclusion: fCalhas high sensitivity for diagnosing NEC in preterm neonates. However, further research is needed to establish its clinical usefulness

Atypical presentation of Niemann-Pick disease

Niemann-Pick (NP) disease is a distinct disorder with specific clinical and morphological manifestations. We report a 2-year-oldgirl who presented with normal development, acute onset of pallor, lethargy, and massive splenomegaly, which made us to think ofhemolytic anemia as the initial diagnosis. Her bone marrow done, after initial hematological work up being normal, showed NP cells.As the child did not have any neurological abnormality, she was diagnosed as NP Type B (NPD-B) storage disease. We report it as atypical presentation of NPD-B