The Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX): overview and preliminary results

While the demand for enhancing rainfall through cloud seeding is strong and persistent in the country, considerable uncertainty exists on the success of such an endeavour at a given location. To understand the pathways of aerosol-cloud interaction through which this might be achieved, a national experiment named Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) in two phases, was carried out. The rationale of CAIPEEX, the strategy for conducting the experiment, data quality and potential for path-breaking science are described in this article. Pending completion of quality control and calibration of the CAIPEEX phase-II data, here we present some initial results of CAIPEEX phase-I aimed at documenting the prevailing microphysical characteristics of aerosols and clouds and associated environmental conditions over different regions of the country and under different monsoon conditions with the help of an instrumented research aircraft. First-time simultaneous observations of aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) over the Ganges Valley during monsoon season show very high concentrations (> 1000 cm-3) of CCN at elevated layers. Observations of elevated layers with high aerosol concentration over the Gangetic valley extending up to 6 km and relatively less aerosol concentration in the boundary layer are also documented. We also present evidence of strong cloud- aerosol interaction in the moist environments with an increase in the cloud droplet effective radius. Our observations also show that pollution increases CDNC and the warm rain depth, and delays its initiation. The critical effective radius for warm rain initiation is found to be between 10 and 12 µm in the polluted clouds and it is between 12 and 14 µm in cleaner monsoon clouds

Spectral correlations in a random distributed feedback fibre laser

Random distributed feedback fibre lasers belong to the class of random lasers, where the feedback is provided by amplified Rayleigh scattering on sub-micron refractive index inhomogenities randomly distributed over the fibre length. Despite the elastic nature of Rayleigh scattering, the feedback mechanism has been insofar deemed incoherent, which corresponds to the commonly observed smooth generation spectra. Here, using a real-time spectral measurement technique based on a scanning Fabry-Pérot interferometer, we observe long-living narrowband components in the random fibre laser's spectrum. Statistical analysis of the ∼104 single-scan spectra reveals a preferential interspacing for the components and their anticorrelation in intensities. Furthermore, using mutual information analysis, we confirm the existence of nonlinear correlations between different parts of the random fibre laser spectra. The existence of such narrowband spectral components, together with their observed correlations, establishes a long-missing parallel between the fields of random fibre lasers and conventional random lasers

A design for cancer case–control studies using only incident cases: experience with the GEM study of melanoma

BACKGROUND: The population-based case-control study is not suited to the evaluation of rare genetic (or environmental) factors. The use of a novel case-control design in which cases have second primaries and controls are cancer survivors has been proposed for this purpose. METHODS: We report results from an international study of melanoma that involved population-based ascertainment of incident cases of second or subsequent primary melanoma as the 'case' group and incident cases of first primary melanoma as the 'control' group. We evaluate the validity of the study design by comparing the results obtained for phenotypic factors that have been shown consistently to be associated with melanoma in previous conventional studies with the results from a conventional case-control study conducted in Connecticut and from literature reviews. RESULTS: All but one of the known risk factors for melanoma were shown to be significantly associated with melanoma in our study, though the individual odds ratios appear to be somewhat attenuated relative to the magnitudes typically observed in the literature. CONCLUSIONS: Patients with a second or subsequent primary cancer of a single type represent a potentially valuable and under-utilized resource for the study of cancer aetiology

Local diversity in settlement, demography and subsistence across the southern Indian Neolithic-Iron Age transition: site growth and abandonment at Sanganakallu-Kupgal

The Southern Indian Neolithic-Iron Age transition demonstrates considerable regional variability in settlement location, density, and size. While researchers have shown that the region around the Tungabhadra and Krishna River basins displays significant subsistence and demographic continuity, and intensification, from the Neolithic into the Iron Age ca. 1200 cal. BC, archaeological and chronometric records in the Sanganakallu region point to hilltop village expansion during the Late Neolithic and ‘Megalithic’ transition period (ca. 1400–1200 cal. BC) prior to apparent abandonment ca. 1200 cal. BC, with little evidence for the introduction of iron technology into the region. We suggest that the difference in these settlement histories is a result of differential access to stable water resources during a period of weakening and fluctuating monsoon across a generally arid landscape. Here, we describe well-dated, integrated chronological, archaeobotanical, archaeozoological and archaeological survey datasets from the Sanganakallu-Kupgal site complex that together demonstrate an intensification of settlement, subsistence and craft production on local hilltops prior to almost complete abandonment ca. 1200 cal. BC. Although the southern Deccan region as a whole may have witnessed demographic increase, as well as subsistence and cultural continuity, at this time, this broader pattern of continuity and resilience is punctuated by local examples of abandonment and mobility driven by an increasing practical and political concern with water

The cloud aerosol interaction and precipitation enhancement experiment (CAIPEEX): Overview and preliminary results

While the demand for enhancing rainfall through cloud seeding is strong and persistent in the country, considerable uncertainty exists on the success of such an endeavour at a given location. To understand the pathways of aerosol-cloud interaction through which this might be achieved, a national experiment named Cloud Aerosol Interaction and Precipitation Enhancement EXperiment (CAIPEEX) in two phases, was carried out. The rationale of CAIPEEX, the strategy for conducting the experiment, data quality and potential for path-breaking science are described in this article. Pending completion of quality control and calibration of the CAIPEEX phase-II data, here we present some initial results of CAIPEEX phase-I aimed at documenting the prevailing microphysical characteristics of aerosols and clouds and associated environmental conditions over different regions of the country and under different monsoon conditions with the help of an instrumented research aircraft. First-time simultaneous observations of aerosol, cloud condensation nuclei (CCN) and cloud droplet number concentration (CDNC) over the Ganges Valley during monsoon season show very high concentrations (> 1000 cm-3) of CCN at elevated layers. Observations of elevated layers with high aerosol concentration over the Gangetic valley extending up to 6 km and relatively less aerosol concentration in the boundary layer are also documented. We also present evidence of strong cloud- aerosol interaction in the moist environments with an increase in the cloud droplet effective radius. Our observations also show that pollution increases CDNC and the warm rain depth, and delays its initiation. The critical effective radius for warm rain initiation is found to be between 10 and 12 μm in the polluted clouds and it is between 12 and 14 μm in cleaner monsoon clouds

Ambient UV, personal sun exposure and risk of multiple primary melanomas

Sun exposure is the main cause of melanoma in populations of European origin. No previous study has examined the effect of sun exposure on risk of multiple primary melanomas compared with people who have one melanoma

Electrons, Photons, and Force: Quantitative Single-Molecule Measurements from Physics to Biology

Single-molecule measurement techniques have illuminated unprecedented details of chemical behavior, including observations of the motion of a single molecule on a surface, and even the vibration of a single bond within a molecule. Such measurements are critical to our understanding of entities ranging from single atoms to the most complex protein assemblies. We provide an overview of the strikingly diverse classes of measurements that can be used to quantify single-molecule properties, including those of single macromolecules and single molecular assemblies, and discuss the quantitative insights they provide. Examples are drawn from across the single-molecule literature, ranging from ultrahigh vacuum scanning tunneling microscopy studies of adsorbate diffusion on surfaces to fluorescence studies of protein conformational changes in solution