Can global warming make Indian monsoon weather less predictable?

Reliable medium range prediction of monsoon weather is crucial for disaster preparedness. Weather in tropics, controlled by fast growing convective instabilities is, however, intrinsically less predictable than that in extra-tropics. Increased frequency and intensity of extreme rain events in the tropics in the backdrop of global warming has a potential for further decreasing the potential predictability of the tropical weather. Using nonlinear dynamical techniques on gridded daily rainfall data over India for 104 years (1901-2004), here we show that the deterministic predictability of monsoon weather over central India in the latest quarter of the period has indeed decreased significantly compared to that in the earlier three quarters. The decrease of initial error doubling time from approximately 3.0 days to 1.5 days is consistent with higher frequency of extreme events and increased potential instability of the atmosphere in the recent quarter. To overcome the increased difficulty in predicting monsoon weather, significant increase in efforts to improve models, observations and enhancement of computing power would be required

On Some properties of Di-hadronic states

The binding energies of di- hadronic states have been calculated assuming a 'molecular' interaction provided by the asymptotic expression of the residual confined gluon exchange potential between the component hadrons in the system. Meson- meson and meson- baryon states have been studied in detail and a mass formula has been used to calculate total mass of the 'molecules'.Comment: 11 page

Struggling to a monumental triumph : Re-assessing the final stages of the smallpox eradication program in India, 1960-1980

The global smallpox program is generally presented as the brainchild of a handful of actors from the WHO headquarters in Geneva and at the agency's regional offices. This article attempts to present a more complex description of the drive to eradicate smallpox. Based on the example of India, a major focus of the campaign, it is argued that historians and public health officials should recognize the varying roles played by a much wider range of participants. Highlighting the significance of both Indian and international field officials, the author shows how bureaucrats and politicians at different levels of administration and society managed to strengthen—yet sometimes weaken—important program components. Centrally dictated strategies developed at WHO offices in Geneva and New Delhi, often in association with Indian federal authorities, were reinterpreted by many actors and sometimes changed beyond recognition

Monsoon Intraseasonal Oscillations as simulated by the Superparameterized Community Atmosphere Model

The relative success of the Community Atmosphere Model with superparameterized convection (SP-CAM) in simulating the space-time characteristics of the Madden Julian Oscillation encourages us to examine its simulation of the Indian summer monsoon and monsoon intraseasonal oscillations (MISOs). While the model simulates the onset and withdrawal of the Indian monsoon realistically, it has a significant wet bias in boreal summer precipitation over the Asian monsoon region. The space-time characteristics of the MISOs simulated by the SP-CAM are examined in detail and compared with those of the observed MISO to gain insight into the model's bias in simulating the seasonal mean. During northern summer, the model simulates a 20 day mode and a 60 day mode in place of the observed 15 and 45 day modes, respectively. The simulated 20 day mode appears to have no observed analog with a baroclinic vertical structure and strong northward propagation over Indian longitudes. The simulated 60 day mode seems to be a lower-frequency version of the observed 45 day mode with relatively slower northward propagation. The model's underestimation of light rain events and overestimation of heavy rain events are shown to be responsible for the wet bias of the model. More frequent occurrence of heavy rain events in the model is, in turn, related to the vertical structure of the higher-frequency modes. Northward propagation of the simulated 20 day mode is associated with a strong cyclonic vorticity at low levels north of the heating maximum associated with a smaller meridional scale of the simulated mode. The simulated vertical structure of heating indicates a strong maximum in the upper troposphere between 200 and 300 hPa. Such a heating profile seems to generate a higher-order baroclinic mode response with smaller meridional structure, stronger low-level cyclonic vorticity, enhanced low-level moisture convergence, and higher precipitation. Therefore, the vertical structure of heating simulated by the cloud-resolving model within SP-CAM may hold the key for improving the precipitation bias in the model

Prospect of determining the Dirac/Majorana state of neutrino by Multi-OWL experiment

We consider the non-radiative two body decay of a neutrino to a daughter neutrino with degraded energy and a very light particle (Majoron). Ultrahigh energy neutrinos from an astrophysical source like a Gamma Ray Burst undergoing this decay process are found to produce different number of events in the detector depending on whether they are Majorana or Dirac particles. The next generation large scale experiments like Multi-OWL is expected to provide us an accurate determination of the flux of neutrinos from astrophysical sources and this may enable us to distinguish between the Dirac and Majorana nature of neutrino.Comment: 18 pages latex, no figure. Journal of Phys. G in pres

From Free Fields to AdS -- II

We continue with the program of hep-th/0308184 to implement open-closed string duality on free gauge field theory (in the large $N$ limit). In this paper we consider correlators such as \la \prod_{i=1}^n \Tr\Phi^{J_i}(x_i)\ra. The Schwinger parametrisation of this $n$-point function exhibits a partial gluing up into a set of basic skeleton graphs. We argue that the moduli space of the planar skeleton graphs is exactly the same as the moduli space of genus zero Riemann surfaces with $n$ holes. In other words, we can explicitly rewrite the $n$-point (planar) free field correlator as an integral over the moduli space of a sphere with $n$ holes. A preliminary study of the integrand also indicates compatibility with a string theory on $AdS$. The details of our argument are quite insensitive to the specific form of the operators and generalise to diagrams of higher genus as well. We take this as evidence of the field theory's ability to reorganise itself into a string theory.Comment: 26 pages, 2 figures; v2. some additional comments, references adde

Assessment of the Albumin-Bilirubin (ALBI) Grade as a Prognostic Indicator for Hepatocellular Carcinoma Patients Treated With Radioembolization.

OBJECTIVE: As the utility of Child-Pugh (C-P) class is limited by the subjectivity of ascites and encephalopathy, we evaluated a previously established objective method, the albumin-bilirubin (ALBI) grade, as a prognosticator for yttrium-90 radioembolization (RE) treatment for patients with hepatocellular carcinoma (HCC). MATERIALS AND METHODS: A total of 117 patients who received RE for HCC from 2 academic centers were reviewed and stratified by ALBI grade, C-P class, and Barcelona Clinic Liver Cancer stage. The overall survival (OS) according to these 3 criteria was evaluated by Kaplan-Meier survival analysis. The utilities of C-P class and ALBI grade as prognostic indicators were compared using the log-rank test. Multivariate Cox regression analysis was performed to identify additional predictive factors. RESULTS: Patients with ALBI grade 1 (n=49) had superior OS than those with ALBI grade 2 (n=65) (P=0.01). Meanwhile, no significant difference was observed in OS between C-P class A (n=100) and C-P class B (n=14) (P=0.11). For C-P class A patients, the ALBI grade (1 vs. 2) was able to stratify 2 clear and nonoverlapping subgroups with differing OS curves (P=0.03). Multivariate Cox regression test identified alanine transaminase, Barcelona Clinic Liver Cancer stage, and ALBI grade as the strongest prognostic factors for OS (P\u3c0.10). CONCLUSIONS: ALBI grade as a prognosticator has demonstrated clear survival discrimination that is superior to C-P class among HCC patients treated with RE, particularly within the subgroup of C-P class A patients. ALBI grade is useful for clinicians to make decisions as to whether RE should be recommended to patients with HCC

Second Generation of Composite Fermions in the Hamiltonian Theory

In the framework of a recently developed model of interacting composite fermions restricted to a single level, we calculate the activation gaps of a second generation of spin-polarized composite fermions. These composite particles consist each of a composite fermion of the first generation and a vortex-like excitation and may be responsible for the recently observed fractional quantum Hall states at unusual filling factors such as nu=4/11,5/13,5/17, and 6/17. Because the gaps of composite fermions of the second generation are found to be more than one order of magnitude smaller than those of the first generation, these states are less visible than the usual states observed at filling factors nu=p/(2ps+1). Their stability is discussed in the context of a pseudopotential expansion of the composite-fermion interaction potential.Comment: 5 pages, 3 figures; after publication in PRB, we have realized that a factor was missing in one of the expressions; the erroneous results are now corrected; an erratum has been sent to PR