Tropical cyclone activity enhanced by Sahara greening and reduced dust emissions during the African Humid Period

Tropical cyclones (TCs) can have devastating socioeconomic impacts. Understanding the nature and causes of their variability is of paramount importance for society. However, historical records of TCs are too short to fully characterize such changes and paleo-sediment archives of Holocene TC activity are temporally and geographically sparse. Thus, it is of interest to apply physical modeling to understanding TC variability under different climate conditions. Here we investigate global TC activity during a warm climate state (mid-Holocene, 6,000 yBP) characterized by increased boreal summer insolation, a vegetated Sahara, and reduced dust emissions. We analyze a set of sensitivity experiments in which not only solar insolation changes are varied but also vegetation and dust concentrations. Our results show that the greening of the Sahara and reduced dust loadings lead to more favorable conditions for tropical cyclone development compared with the orbital forcing alone. In particular, the strengthening of the West African Monsoon induced by the Sahara greening triggers a change in atmospheric circulation that affects the entire tropics. Furthermore, whereas previous studies suggest lower TC activity despite stronger summer insolation and warmer sea surface temperature in the Northern Hemisphere, accounting for the Sahara greening and reduced dust concentrations leads instead to an increase of TC activity in both hemispheres, particularly over the Caribbean basin and East Coast of North America. Our study highlights the importance of regional changes in land cover and dust concentrations in affecting the potential intensity and genesis of past TCs and suggests that both factors may have appreciable influence on TC activity in a future warmer climate.National Science Foundation (U.S.) (Grant AGS-1461517

Dark clouds in co-creation, and their silver linings practical challenges we faced in a participatory project in a resource-constrained community in India, and how we overcame (some of) them

BACKGROUND: While any type of field-based research is challenging, building action-oriented, participatory research in resource-constrained settings can be even more so. OBJECTIVE: In this article, we aim to examine and provide insights into some of the practical challenges that were faced during the course of a participatory project based in two non-notified slums in Bangalore, India, aiming to build solutions to indoor air pollution from cooking on traditional cook stoves. METHODS: The article draws upon experiences of the authors as field researchers engaged in a community-based project that adopted an exploratory, iterative design to its planning and implementation, which involved community visits, semi-structured interviews, prioritization workshops, community forums, photo voice activities, chulha-building sessions and cooking trials. RESULTS: The main obstacles to field work were linked to fostering open, continued dialogue with the community, aimed at bridging the gap between the 'scientific' and the 'local' worlds. Language and cultural barriers led to a reliance on interpreters, which affected both the quality of the interaction as well as the relationship between the researchers and the community that was built out of that interaction. The transience in housing and location of members of the community also led to difficulties in following up on incomplete information. Furthermore, facilitating meaningful participation from the people within the context of restricted resources, differing priorities, and socio-cultural diversity was particularly challenging. These were further compounded by the constraints of time and finances brought on by the embeddedness of the project within institutional frameworks and conventional research requirements of a fixed, pre-planned and externally determined focus, timeline, activities and benchmarks for the project. CONCLUSIONS: This article calls for revisiting of scientific conventions and funding prerequisites, in order to create spaces that support flexible, emergent and adaptive field-based research projects which can respond effectively to the needs and priorities of the community

Connecting Word with World: Reading as an Act of Cognitive Exploration

In spite of the many methodologies tried out in the last two centuries in India, the teaching-learning of English is still heavily dependent on reading. The main reason may be attributed to the fact that all subjects including science and technology have their mainstay in reading both in classrooms and at home. Even then, adequate attention has not been paid to reading instruction at the primary and secondary levels; as a result, when the learners reach the tertiary level where they are supposed to work on their own by reading and referring to books and journals, most of them end up as miserable failures just because of their poor and inadequate reading habits. While teachers focus only on the final outcome, tests and examinations solely depend on the learner’s net result of reading which is expected to get reflected in writing. A serious attempt to follow the reader in his course of reading may reveal the myriads of complexities which the act of reading passes through. This paper is just an attempt of making teachers of English aware of the fact that a learner’s success or failure in his academic pursuit is almost determined by his reading efficiency. Therefore this paper outlines the intricate cognitive processes involved in reading a second language

Effects of phosphorus implantation time on the optical, structural, and elemental properties of ZnO thin films and its correlation with the 3.31-eV peak

To study the effects of implantation on ZnO thin films grown on Si substrates, we have subjected it to phosphorous ion implantation for 10, 40, and 70 s through plasma immersion ion implantation and rapid thermal annealing. Low-temperature photoluminescence spectra of the as-implanted samples exhibited a reduction in the donor-bound exciton peak at 3.36 eV with implantation time. The photoluminescence spectrum of the 70 s implanted 1000 degrees C-annealed sample confirmed acceptor-type doping. X-ray diffraction measurements showed a reduction in the c-axis length along the direction with implantation time, evidencing phosphorous-ion incorporation in the implanted films, which was further confirmed by the blue shifting of the E2 high peak in the Raman spectra. XPS measurements affirmed the presence of the P 2p peak, a signature of P-O bond, and confirmed the substitution of Zn atoms by P atoms and the subsequent formation of the Pzn-2Vzn complex essential for acceptor-type conductivity. (C) 2018 Elsevier B.V. All rights reserved

Glass transformation studies in Ge-Se-Bi system

The thermal behavior of bulk glasses in the $Ge_{20}Se_{80-x} Bi_x$ (x = 2.5, 4.0, 6.0 at %) system is studied using modulated differential scanning calorimetry (MDSC). All samples have the same thermal history as a result of heating to a temperature above the glass transition point, equilibrating, and then cooling. The total heat flow, modulated heat flow, reversing heat flow, and nonreversing heat flow under heating and cooling schedules are measured. The glass transition temperature $T_g$, the relaxation enthalpy \Delta H, the specific capacity $C_p$, and the specific heat capacity difference $\Delta C_p=C_{pl} - C_{pg}$, which characterize the thermal events in the glass transition region, are also determined. These parameters reveal an increase with x, which can be attributed to the increase in the average coordination number with an increase in the bismuth content (at \%) in the composite. The ratio of heat capacities $C_{pl} / C_{pg}$ , the width of the glass transition temperature range $\Delta T_g$, and the activation enthalpy for glass transition $\Delta H _{Tg}$ are also studied. The values of the ratio $C_{pl}/C_{pg}$ vary in the range between 1.038 and 1.112. The activation energy of crystallization is evaluated using the Kissinger, modified JMA, and Matusita equations, which is found to be in the range of 100.92 kJ/mol