High-precision force sensing using a single trapped ion

We introduce quantum sensing schemes for measuring very weak forces with a single trapped ion. They use the spin-motional coupling induced by the laser-ion interaction to transfer the relevant force information to the spin-degree of freedom. Therefore, the force estimation is carried out simply by observing the Ramsey-type oscillations of the ion spin states. Three quantum probes are considered, which are represented by systems obeying the Jaynes-Cummings, quantum Rabi (in 1D) and Jahn-Teller (in 2D) models. By using dynamical decoupling schemes in the Jaynes-Cummings and Jahn-Teller models, our force sensing protocols can be made robust to the spin dephasing caused by the thermal and magnetic field fluctuations. In the quantum-Rabi probe, the residual spin-phonon coupling vanishes, which makes this sensing protocol naturally robust to thermally-induced spin dephasing. We show that the proposed techniques can be used to sense the axial and transverse components of the force with a sensitivity beyond the yN $/\sqrt{\text{Hz}}$ range, i.e. in the xN$/\sqrt{\text{Hz}}$ (xennonewton, $10^{-27}$). The Jahn-Teller protocol, in particular, can be used to implement a two-channel vector spectrum analyzer for measuring ultra-low voltages.Comment: 7 pages, 4 figure

Analytic approximations to the phase diagram of the Jaynes-Cummings-Hubbard model with application to ion chains

We discuss analytic approximations to the ground state phase diagram of the homogeneous Jaynes-Cummings-Hubbard (JCH) Hamiltonian with general short-range hopping. The JCH model describes e.g. radial phonon excitations of a linear chain of ions coupled to an external laser field tuned to the red motional sideband with Coulomb mediated hopping or an array of high-$Q$ coupled cavities containing a two-level atom and photons. Specifically we consider the cases of a linear array of coupled cavities and a linear ion chain. We derive approximate analytic expressions for the boundaries between Mott-insulating and superfluid phases and give explicit expressions for the critical value of the hopping amplitude within the different approximation schemes. In the case of an array of cavities, which is represented by the standard JCH model we compare both approximations to numerical data from density-matrix renormalization group (DMRG) calculations.Comment: 9 pages, 5 figures, extended and corrected second versio

Social Capital and the Paradox of Poor but Healthy Groups in the United States

Increased income strongly correlates with improved health and lower mortality risk. Yet in spite of having a lower mean and median income, both Hispanics and the foreign-born living within the U.S. have higher longevity compared with native-born, non-Hispanics. We explored the role of structural social capital in conferring protection against poor health outcomes among Hispanics and the foreign-born in the US. We used the National Health and Nutrition Examination Survey III 1988–1994 linked to prospective mortality follow up to examine the relationship between five measures of structural social capital and: (1) intermediate health outcomes (blood pressure, plasma fibrinogen, C-reactive protein, and total cholesterol) and (2) a distal outcome (all cause mortality). The foreign-born and Hispanics generally had lower measures of structural social capital relative to native-born non-Hispanics. Additionally, while structural social capital was protective against poor health or mortality among native-born persons, the association disappeared for Hispanics and the foreign-born

What could infant and young child nutrition learn from sweatshops?

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Adequate infant and young child nutrition demands high rates of breastfeeding and good access to nutrient rich complementary foods, requiring public sector action to promote breastfeeding and home based complementary feeding, and private sector action to refrain from undermining breastfeeding and to provide affordable, nutrient rich complementary foods. Unfortunately, due to a lack of trust, the public and private sectors, from both the North and the South, do not work well together in achieving optimal infant and young child nutrition. DISCUSSION: As the current debate in infant and young child nutrition is reminiscent of the "sweatshop" debate fifteen years ago, we argue that lessons from the sweatshops debate regarding cooperation between public and private sectors - and specific organizational experiences such as the Ethical Trading Initiative in which companies, trade unions, and civil society organizations work together to enhance implementation of labour standards and address alleged allegations - could serve as a model for improving cooperation and trust between public, civil society and private groups, and ultimately health, in infant and young child nutrition. SUMMARY: Lessons from the sweatshops debate could serve as a model to promote cooperation and trust between public and private groups, such that they learn to work together towards their common goal of improving infant and young child nutrition

Science-based health innovation in Tanzania: bednets and a base for invention

<p>Abstract</p> <p>Background</p> <p>Tanzania is East Africa’s largest country. Although it is socially diverse, it has experienced general political stability since independence in 1964. Despite gradual economic development and Tanzania’s status as one of the biggest recipients of aid in Africa, health status remains poor. This paper explores Tanzania’s science-based health innovation system, and highlights areas which can be strengthened.</p> <p>Methods</p> <p>Qualitative case study research methodology was used. Data were collected through reviews of academic literature and policy documents, and through open-ended, face-to-face interviews with 52 people from across the science-based health innovation system over two visits to Tanzania from July to October 2007.</p> <p>Results and discussion</p> <p>Tanzania has a rich but complex S&T governance landscape, with the public sector driving the innovation agenda through a series of different bodies which are not well-coordinated. It has some of the leading health research on the continent at the University of Dar es Salaam, Muhimbili University of Health and Applied Sciences, the National Institute for Medical Research and the Ifakara Medical Institute, with strong donor support. Tanzania has found developing an entrepreneurial culture difficult; nevertheless projects such as the clusters initiative at the University of Dar es Salaam are encouraging low-tech innovation and overcoming knowledge-sharing barriers. In the private sector, one generics company has developed a South-South collaboration to enable technology transfer and hence the local production of anti-retrovirals. Local textile company A to Z Textiles is now manufacturing 30 million insecticide impregnated bednets a year.</p> <p>Conclusions</p> <p>To have a coherent vision for innovation, Tanzania may wish to address some key issues: coordination across stakeholders involved with health research, increasing graduates in health-related disciplines, and building capabilities in biological testing, preclinical testing, formulation and standardization, and related areas important to moving from basic research to applications. The private sector can be encouraged to innovate through improved access to financing, and incentives for R&D. The diaspora community represents an untapped source for partnerships and access to other developing world markets and technology. The government may wish to set up mechanisms to encourage south-south collaborations, and to bring the public and private sector together around specific projects to help realize the country’s innovation potential.</p

Turning science into health solutions: KEMRI’s challenges as Kenya’s health product pathfinder

BACKGROUND: A traditional pathway for developing new health products begins with public research institutes generating new knowledge, and ends with the private sector translating this knowledge into new ventures. But while public research institutes are key drivers of basic research in sub-Saharan Africa, the private sector is inadequately prepared to commercialize ideas that emerge from these institutes, resulting in these institutes taking on the role of product development themselves to alleviate the local disease burden. In this article, the case study method is used to analyze the experience of one such public research institute: the Kenya Medical Research Institute (KEMRI). DISCUSSION: Our analysis indicates that KEMRI's product development efforts began modestly, and a manufacturing facility was constructed with a strategy for the facility's product output which was not very successful. The intended products, HIV and Hepatitis B diagnostic kits, had a short product life cycle, and an abrupt change in regulatory requirements left KEMRI with an inactive facility. These problems were the result of poor innovation management capacity, variability in domestic markets, lack of capital to scale up technologies, and an institutional culture that lacked innovation as a priority.However, KEMRI appears to have adapted by diversifying its product line to mitigate risk and ensure continued use of its manufacturing facility. It adopted an open innovation business model which linked it with investors, research partnerships, licensing opportunities, and revenue from contract manufacturing. Other activities that KEMRI has put in place over several years to enhance product development include the establishment of a marketing division, development of an institutional IP policy, and training of its scientists on innovation management. SUMMARY: KEMRI faced many challenges in its attempt at health product development, including shifting markets, lack of infrastructure, inadequate financing, and weak human capital with respect to innovation. However, it overcame them through diversification, partnerships and changes in culture. The findings could have implications for other research institutes in Sub-Saharan Africa seeking to develop health products. Such institutes must analyze potential demand and uptake, yet be prepared to face the unexpected and develop appropriate risk-mitigating strategies

Access and use of human tissues from the developing world: ethical challenges and a way forward using a tissue trust

<p>Abstract</p> <p>Background</p> <p>Scientists engaged in global health research are increasingly faced with barriers to access and use of human tissues from the developing world communities where much of their research is targeted. In part, the problem can be traced to distrust of researchers from affluent countries, given the history of 'scientific-imperialism' and 'biocolonialism' reflected in past well publicized cases of exploitation of research participants from low to middle income countries.</p> <p>Discussion</p> <p>To a considerable extent, the failure to adequately engage host communities, the opacity of informed consent, and the lack of fair benefit-sharing have played a significant role in eroding trust. These ethical considerations are central to biomedical research in low to middle income countries and failure to attend to them can inadvertently contribute to exploitation and erode trust. A 'tissue trust' may be a plausible means for enabling access to human tissues for research in a manner that is responsive to the ethical challenges considered.</p> <p>Summary</p> <p>Preventing exploitation and restoring trust while simultaneously promoting global health research calls for innovative approaches to human tissues research. A tissue trust can reduce the risk of exploitation and promote host capacity as a key benefit.</p