Radiative Heating of an Ice-Free Arctic Ocean

During recent decades, there has been dramatic Arctic sea ice retreat. This has reduced the top-of-atmosphere albedo, adding more solar energy to the climate system. There is substantial uncertainty regarding how much ice retreat and associated solar heating will occur in the future. This is relevant to future climate projections, including the timescale for reaching global warming stabilization targets. Here we use satellite observations to estimate the amount of solar energy that would be added in the worst-case scenario of a complete disappearance of Arctic sea ice throughout the sunlit part of the year. Assuming constant cloudiness, we calculate a global radiative heating of 0.71 W/m2 relative to the 1979 baseline state. This is equivalent to the effect of one trillion tons of CO2 emissions. These results suggest that the additional heating due to complete Arctic sea ice loss would hasten global warming by an estimated 25 years

Studies on the immunopathology of tuberculosis

In this presentation, two aspects concerning the immunopathology of tuberculosis at the microanatomical level will be considered. The material for this presentation is drawn from our studies on tuberculous lymphadenitis (450 cases) and skin tuberculosis (270 cases). The first question to be considered is ‘when is it necessary to demonstrate the components of M.tuberculosis in the tissues?’ The second is the question of the involvement of humoral immune factors associated with some of the histological manifestations of tuberculosis

The pathophysiology of the complement system in leprosy

The complement system, which consists of a group of proteins and glycoproteins, generally serves to amplify the effects of the interaction of antigen with antibody. In addition, this system, independent of immune mechanisms, can initiate inflammatory responses and function as an important first line of defence. Furthermore, complement plays a cardinal role in metabolising antigen-antibody complexes. More recently, the immunomodulatory effects of several of its components are also being studied. It is currently held that the elimination of Mycobacterium leprae from the human host is mainly through the T-lymphocytes and macrophages and that the complement system is not involved in this process. Nevertheless, in view of the active interaction of M. leprae with the complement system and the form&on of large amounts of immune complexes(IC) in leprosy, the importance of this system in modulating certain immunopathogenetic phenomena is being recognized now. In this communication, the current state knowledge in this field will be reviewed and an attempt will be made to identify possible areas of future research where lacunae exist

Thermal energy storage systems using fluidized bed heat exchangers

The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described

Evidence of surface cooling from absorbing aerosols

Anthropogenic emissions over the Asian region have grown rapidly with increase in population and industrialization. Air-pollutants from this region lead to a brownish haze over most of the North Indian Ocean and South Asia during winter and spring. The haze, with as much as 10-15 of black carbon (by mass), is known to reduce the surface solar insolation by about 10 (-15 Wm -2) and nearly double the lower atmospheric solar heating. Here we present an analysis of observed surface-temperature variations over the Indian subcontinent, which filters out effects of greenhouse gases and natural variability. The analysis reveals that the absorbing aerosols have led to a statistically significant cooling of about 0.3°C since the 1970s. The seasonally asymmetric cooling, which is consistent with the seasonality of the South Asian aerosol forcing, raises the new possibility that the surface cooling underneath the polluted regions, is balanced by warming elsewhere

Observation of a 2D Bose-gas: from thermal to quasi-condensate to superfluid

We present experimental results on a Bose gas in a quasi-2D geometry near the Berezinskii, Kosterlitz and Thouless (BKT) transition temperature. By measuring the density profile, \textit{in situ} and after time of flight, and the coherence length, we identify different states of the gas. In particular, we observe that the gas develops a bimodal distribution without long range order. In this state, the gas presents a longer coherence length than the thermal cloud; it is quasi-condensed but is not superfluid. Experimental evidence indicates that we observe the superfluid transition (BKT transition).Comment: 5 pages, 6 figure

Evidence of surface cooling from absorbing aerosols

Anthropogenic emissions over the Asian region have grown rapidly with increase in population and industrialization. Air-pollutants from this region lead to a brownish haze over most of the North Indian Ocean and South Asia during winter and spring. The haze, with as much as 10–15% of black carbon (by mass), is known to reduce the surface solar insolation by about 10% (−15 Wm−2) and nearly double the lower atmospheric solar heating. Here we present an analysis of observed surface-temperature variations over the Indian subcontinent, which filters out effects of greenhouse gases and natural variability. The analysis reveals that the absorbing aerosols have led to a statistically significant cooling of about 0.3°C since the 1970s. The seasonally asymmetric cooling, which is consistent with the seasonality of the South Asian aerosol forcing, raises the new possibility that the surface cooling underneath the polluted regions, is balanced by warming elsewhere

Experimental evidence on promotion of electric and improved biomass cookstoves.

Improved cookstoves (ICS) can deliver "triple wins" by improving household health, local environments, and global climate. Yet their potential is in doubt because of low and slow diffusion, likely because of constraints imposed by differences in culture, geography, institutions, and missing markets. We offer insights about this challenge based on a multiyear, multiphase study with nearly 1,000 households in the Indian Himalayas. In phase I, we combined desk reviews, simulations, and focus groups to diagnose barriers to ICS adoption. In phase II, we implemented a set of pilots to simulate a mature market and designed an intervention that upgraded the supply chain (combining marketing and home delivery), provided rebates and financing to lower income and liquidity constraints, and allowed households a choice among ICS. In phase III, we used findings from these pilots to implement a field experiment to rigorously test whether this combination of upgraded supply and demand promotion stimulates adoption. The experiment showed that, compared with zero purchase in control villages, over half of intervention households bought an ICS, although demand was highly price-sensitive. Demand was at least twice as high for electric stoves relative to biomass ICS. Even among households that received a negligible price discount, the upgraded supply chain alone induced a 28 percentage-point increase in ICS ownership. Although the bundled intervention is resource-intensive, the full costs are lower than the social benefits of ICS promotion. Our findings suggest that market analysis, robust supply chains, and price discounts are critical for ICS diffusion

Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze

Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects. The haze particles consisted of several inorganic and carbonaceous species, including absorbing black carbon clusters, fly ash, and mineral dust. The most striking result was the large loading of aerosols over most of the South Asian region and the North Indian Ocean. The January to March 1999 visible optical depths were about 0.5 over most of the continent and reached values as large as 0.2 over the equatorial Indian ocean due to long-range transport. The aerosol layer extended as high as 3 km. Black carbon contributed about 14% to the fine particle mass and 11% to the visible optical depth. The single-scattering albedo estimated by several independent methods was consistently around 0.9 both inland and over the open ocean. Anthropogenic sources contributed as much as 80% (±10%) to the aerosol loading and the optical depth. The in situ data, which clearly support the existence of the first indirect effect (increased aerosol concentration producing more cloud drops with smaller effective radii), are used to develop a composite indirect effect scheme. The Indo-Asian aerosols impact the radiative forcing through a complex set of heating (positive forcing) and cooling (negative forcing) processes. Clouds and black carbon emerge as the major players. The dominant factor, however, is the large negative forcing (-20±4 W m^(−2)) at the surface and the comparably large atmospheric heating. Regionally, the absorbing haze decreased the surface solar radiation by an amount comparable to 50% of the total ocean heat flux and nearly doubled the lower tropospheric solar heating. We demonstrate with a general circulation model how this additional heating significantly perturbs the tropical rainfall patterns and the hydrological cycle with implications to global climate