Anharmonic phonons in few layer MoS2_2: Raman spectroscopy of ultra low energy compression and shear modes

Molybdenum disulfide (MoS$_2$) is a promising material for making two-dimensional crystals and flexible electronic and optoelectronic devices at the nanoscale. MoS$_2$ flakes can show high mobilities and have even been integrated in nanocircuits . A fundamental requirement for such use is efficient thermal transport. Electronic transport generates heat which needs to be evacuated, more crucially so in nanostructures. Anharmonic phonon-phonon scattering is the dominant intrinsic limitation to thermal transport in insulators. Here, using appropriate samples, ultra-low energy Raman spectroscopy and first principles calculations, we provide a full experimental and theoretical description of compression and shear modes of few-layer (FL) MoS$_2$. We demonstrate that the compression modes are strongly anharmonic with a marked enhancement of phonon-phonon scattering as the number of layers is reduced, most likely a general feature of nanolayered materials with weak interlayer coupling.Comment: 6 pages, 5 figure

The impacts of corporatisation of healthcare on medical practice and professionals in Maharashtra, India

A heterogeneous private sector dominates healthcare provision in many middle-income countries. In India the contemporary period has seen this sector undergo corporatisation processes characterised by emergence of large private hospitals and the takeover of medium-sized and charitable hospitals by corporate entities. Little is known about the operations of these private providers and the effects on healthcare professions as employment shifts from practitioner-owned small and medium hospitals to larger corporate settings. This article uses data from a mixed-methods study in two large cities in Maharashtra, India, to consider the implications of these contemporary changes for the medical profession. Data were collected from semi-structured interviews with 43 respondents who have detailed knowledge of healthcare in Maharashtra, and from a witness seminar on the topic of transformation in Maharashtra’s healthcare system. Transcripts from the interviews and witness seminar were analysed thematically through a combination of deductive and inductive approaches. Our findings point to a restructuring of medical practice in Maharashtra as training shifts towards private education and employment to those corporate hospitals. The latter is fuelled by substantial personal indebtedness, dwindling appeal of government employment, reduced opportunities to work in smaller private facilities, and the perceived benefits of work in larger providers. We describe a ‘re-professionalisation’ of medicine encompassing changes in employment relations, performance targets and constraints placed on professional autonomy within the private healthcare sector, that is accompanied by trends in cost inflation, medical malpractice, and distrust in doctor-patient relationships. The accompanying ‘re-stratification’ within this part of the profession affords prestige and influence to ‘star doctors’ while eroding the status and opportunity for young and early career doctors. The research raises important questions about the role that government and medical professionals’ bodies can, and should, play in contemporary transformation of private healthcare, and the implications of these trends for health systems more broadly

Making Private Health Care Accountable: Mobilising Civil Society and Ethical Doctors in India

Though the private sector dominates health care in India, it lacks social accountability and effective regulation. Hence, health activists and health-care professionals have adopted a three-pronged approach of mobilising civil society for patients’ rights, networking with ethical doctors towards social responsiveness, and advocating with government for accountable regulation. Health movement strategies adopted mainly in Maharashtra State include organising a regional public hearing in collaboration with the National Human Rights Commission; developing ‘Citizen–Doctor Forums’; mobilising citizens around patients’ rights through a ‘people’s poll’; and campaigning for people-oriented regulatory legislation. A national network of doctors is also being developed to promote ethical health care. Key lessons include: identifying patient rights as popular idiom for citizens’ mobilisation, relevance of ethical voices within the medical profession to complement social accountability of private health care, potential of moving beyond citizen–doctor adversarial positions to promote accountable health-care options, and placing participatory social regulation on the agenda.Open Society Foundations, Vozes Desiguais/Unequal Voices, Future Health Systems consortium, the Impact Initiative and Health Systems Globa

Methods of Material and Surface Analysis for the Evaluation of Failure Modes for Electrical Connectors

The development of autonomous vehicles and the integration of new information and communication technologies are making the reliability of electrical systems and components in modern vehicles increasingly important. Electrical connectors are a crucial component in an electrical on-board system. They are exposed to a wide variety of influences by the environment and operating conditions. Thus, the degradation of electrical connectors can occur. Material and surface analysis methods are the tools used to analyze the degradation mechanisms in connectors after lifetime tests, as well as in field operations. Within the framework of this study, a wide variety of methods from the analytical scope are presented and discussed. The connector surfaces degraded by different failure mechanisms are analyzed using various material and surface analysis methods. The quality and the nature of the analyses results obtained from various analysis methods are compared. Also, this study deals with the benefits and limitations, as well as the effort and the specific challenges of different material and surface analytical methods for the evaluation of failure mechanisms from the point of view of a material and surface analyst

Effect of ethrel spray on the ripening behaviour of mango (Mangifera indica L.) variety 'Dashehari'

An experiment was carried out to investigate the effect of post harvest spray of different concentrations (100, 200, 400, 600 and 800 ppm) of ethrel (2-chloroethyl phosphonic acid) on ripening and colour development in ‘Dashehari’ mango fruits harvested in second week of June, 2015. The treated fruits were assessed for physico-chemical parameters such as physiological loss in weight (%), firmness (Kg/cm2), TSS (°Brix), titrable acidity (%), total carotenoids (mg/100g) and peel chlorophyll (mg/100g) and observations were recorded at 2 days interval during 8 days storage at ambient temperature. Changes in total soluble solids (8.5 to 23.23° Brix), total carotenoids (0.807 to 7.12 mg/100g) and PLW (14.58%) showed increasing trends up to 8 days during storage whereas fruit firmness (8.5 to 0.68 Kg/cm2), titrable acidity (1.26 to 0.08%) and total peel chlorophyll (5.2 to 0.14 mg/100g) showed decreasing trends. At the end of the storage period for 8 days, Ethrel spray at 600 ppm induced uniform ripening with attractive yellow colour within 4 days while untreated control fruits failed to ripen uniformly and remain light green even after 8 days of storage. Ripening advances by 4 days in fruits sprayed with 600 ppm ethrel com-pared to unsprayed control fruits

Metal-ligand interplay in strongly-correlated oxides: a parametrized phase diagram for pressure induced spin transitions

We investigate the magnetic properties of archetypal transition-metal oxides MnO, FeO, CoO and NiO under very high pressure by x-ray emission spectroscopy at the K\beta line. We observe a strong modification of the magnetism in the megabar range in all the samples except NiO. The results are analyzed within a multiplet approach including charge-transfer effects. The pressure dependence of the emission line is well accounted for by changes of the ligand field acting on the d electrons and allows us to extract parameters like local d-hybridization strength, O-2p bandwidth and ionic crystal field across the magnetic transition. This approach allows a first-hand insight into the mechanism of the pressure induced spin transition.Comment: 5 pages, 3 figure

Graphene made easy: high quality, large-area samples

We show that by using an original method, bulk graphite can be bonded onto borosilicate glass or potentially any insulating substrate with ionic conductivity and then cleaved off to leave single or few layer graphene on the substrate, identified optically and with Raman spectroscopy. This simple, inexpensive and fast method leads to the preparation of large area graphene and single or few-layer films of layered materials in general. We have prepared mm size few-layer graphene samples and also measured I-V characteristics in a FET. This opens up perspectives both for fundamental research as well as for applications.Comment: 11 pages, 4 figures,Solid State Communications, In pres

Temperature and pressure-induced spin-state transitions in LaCoO3

We report the continuous variation of the spin moment of cobalt in LaCoO3 across its temperature and pressure-induced spin transitions evidenced with K\beta emission spectra. The first thermal transition is best described by a transition to an orbitally nondegenerate intermediate spin (S=1) state. In parallel, continuous redistribution of the 3d electrons is also indicated by partial fluorescence yield X-ray absorption spectra. At high pressure, our study confirms that the material becomes low spin between 40 and 70 kbar at room temperature