The Growth Costs of Malaria

Malaria ranks among the foremost health issues facing tropical countries. In this paper, we explore the determinants of cross-country differences in malaria morbidity, and examine the linkage between malaria and economic growth. Using a classification rule analysis, we confirm the dominant role of climate in accounting for cross-country differences in malaria morbidity. The data, however, do not suggest that tropical location is destiny: controlling for climate, we find that access to rural healthcare and income equality influence malaria morbidity. In a cross-section growth framework, we find a significant negative association between higher malaria morbidity and the growth rate of GDP per capita which is robust to a number of modifications, including controlling for reverse causation. The estimated absolute growth impact of malaria differs sharply across countries; it exceeds a quarter percent per annum in a quarter of the sample countries. Most of these are located in Sub-Saharan Africa (with an estimated average annual growth reduction of 0.55 percent).

Malaria and growth

The authors explore the two-sided link between malaria morbidity and Gross Domestic Product (GDP) per capita growth. Climate significantly affects cross-country differences in malaria morbidity. Tropical location is not destiny, however: greater access to rural health care and greater income equality are associated with lower malaria morbidity. But the interpretation of this link is ambiguous: does greater income inequality allow for improved anti-malaria efforts, or does malaria itself increase income inequality? Allowing for two-sided causation, the authors find a significant negative causal effect running from malaria morbidity to the growth rate of GDP per capita. In about a quarter of their sample countries, malaria is estimated to reduce GDP per capita growth by at least 0.25 percentage point a year.Health Monitoring&Evaluation,Public Health Promotion,Disease Control&Prevention,Early Child and Children's Health,Climate Change,Health Monitoring&Evaluation,Early Child and Children's Health,Climate Change,Poverty and Health,Health Service Management and Delivery

Optimal control of serial, multi-echelon inventory/production systems with periodic batching

We consider a single-item, periodic-review, serial, multi-echelon inventory system, with linear inventory holding and penalty costs. In order to facilitate shipment consolidation and capacity planning, we assume the system has implemented periodic batching: each stage is allowed to order at given equidistant times. Further, for each stage except the most downstream one, the reorder interval is assumed to be an integer multiple of the reorder interval of the next downstream stage. This reflects the fact that the further upstream in a supply chain, the higher setup times and costs tend to be, and thus stronger batching is desired. Our model with periodic batching is a direct generalization of the serial, multi-echelon model of Clark and Scarf (1960). For this generalized model, we prove the optimality of basestock policies, we derive Newsboy-type characterizations for the optimal basestock levels, and we describe an efficient exact solution procedure for the case with mixed Erlang demands. Finally, we present extensions to assembly systems and to systems with a modified fill rate constraint instead of backorder costs. Subject classification: Inventory/Production: Multi-echelon, stochastic demand, periodic batching, optimal policies.

Health literacy, health status, and healthcare utilization of Taiwanese adults: results from a national survey

Abstract Background Low health literacy is considered a worldwide health threat. The purpose of this study is to assess the prevalence and socio-demographic covariates of low health literacy in Taiwanese adults and to investigate the relationships between health literacy and health status and health care utilization. Methods A national survey of 1493 adults was conducted in 2008. Health literacy was measured using the Mandarin Health Literacy Scale. Health status was measured based on self-rated physical and mental health. Health care utilization was measured based on self-reported outpatient clinic visits, emergency room visits, and hospitalizations. Results Approximately thirty percent of adults were found to have low (inadequate or marginal) health literacy. They tended to be older, have fewer years of schooling, lower household income, and reside in less populated areas. Inadequate health literacy was associated with poorer mental health (OR, 0.57; 95% CI, 0.35-0.91). No association was found between health literacy and health care utilization even after adjusting for other covariates. Conclusions Low (inadequate and marginal) health literacy is prevalent in Taiwan. High prevalence of low health literacy is not necessarily indicative of the need for interventions. Systematic efforts to evaluate the impact of low health literacy on health outcomes in other countries would help to illuminate features of health care delivery and financing systems that may mitigate the adverse health effects of low health literacy.http://deepblue.lib.umich.edu/bitstream/2027.42/78252/1/1471-2458-10-614.xmlhttp://deepblue.lib.umich.edu/bitstream/2027.42/78252/2/1471-2458-10-614.pdfPeer Reviewe

Anisotropic hyperfine interaction of surface-adsorbed single atoms

Hyperfine interactions between electron and nuclear spins have been widely used in material science, organic chemistry, and structural biology as a sensitive probe to the local chemical environment through spatial identification of nuclear spins. With the nuclear spins identified, the isotropic and anisotropic components of the hyperfine interactions in turn offer unique insight into the electronic ground-state properties of the paramagnetic centers. However, traditional ensemble measurements of hyperfine interactions average over a macroscopic number of spins with different geometrical locations and nuclear isotopes. Here, we use a scanning tunneling microscope (STM) combined with electron spin resonance (ESR) to measure hyperfine spectra of hydrogenated-titanium (Ti) atoms on MgO/Ag(100) and thereby determine the isotropic and anisotropic hyperfine interactions at the single-atom level. By combining vector-field ESR spectroscopy with STM-based atom manipulation, we characterize the full hyperfine tensor of individual Ti-47 and Ti-49 atoms and identify significant spatial anisotropy of hyperfine interaction for both isotopes when they are adsorbed at low-symmetry binding sites. Density functional theory calculations reveal that the large hyperfine anisotropy arises from a highly anisotropic distribution of the ground-state electron spin density. Our work highlights the power of ESR-STM-enabled single-atom hyperfine spectroscopy as a powerful tool in revealing ground-state electronic structures and atomic-scale chemical environments with nano-electronvolt resolution.Comment: 17 pages, 4 figure

The UV colours of high-redshift early-type galaxies: evidence for recent star formation and stellar mass assembly over the last 8 billion years

We combine deep UBVRIzJK photometry from the Multiwavelength Survey by Yale-Chile (MUSYC) with redshifts from the COMBO-17 survey to perform a large-scale study of the rest-frame ultraviolet (UV) properties of 674 high-redshift (0.5<z<1) early-type galaxies, drawn from the Extended Chandra Deep Field South (E-CDFS). Galaxy morphologies are determined through visual inspection of Hubble Space Telescope (HST) images taken from the GEMS survey. We harness the sensitivity of the UV to young (<1 Gyr old) stars to quantify the recent star formation history of early-type galaxies across a range of luminosities (-23.5 < M(V) < -18). Comparisons to simple stellar populations forming at high redshift indicate that only ~1.1 percent of early-types in this sample are consistent with purely passive ageing since z=2. Parametrising the recent star formation (RSF) in terms of the mass fraction of stars less than a Gyr old, we find that the early-type population as a whole shows a typical RSF between 5 and 13% in the redshift range 0.5<z<1. Early-types on the UV red sequence show RSF values less than 5% while the reddest early-types are virtually quiescent with RSF values of ~1%. We find compelling evidence that early-types of all luminosities form stars over the lifetime of the Universe, although the bulk of their star formation is already complete at high redshift. This tail-end of star formation is measurable and not negligible, with luminous (-23<M(V)<-20.5) early-types potentially forming 10-15% of their mass since z=1, with their less luminous (M(V)>-20.5) counterparts potentially forming 30-60 percent of their mass in the same redshift range. (abridged)Comment: Submitted to MNRA

A coincidence of disturbed morphology and blue UV colour: minor-merger driven star formation in early-type galaxies at z~0.6

We exploit multi-wavelength photometry of early-type galaxies (ETGs) in the COSMOS survey to demonstrate that the low-level star formation activity in the ETG population at intermediate redshift is likely to be driven by minor mergers. Splitting the ETGs into galaxies that show disturbed morphologies indicative of recent merging and those that appear relaxed, we find that ~32% of the ETG population appears to be morphologically disturbed. While the relaxed objects are almost entirely contained within the UV red sequence, their morphologically disturbed counterparts dominate the scatter to blue UV colours, regardless of luminosity. Empirically and theoretically determined major-merger rates in the redshift range z<1 are several times too low to account for the fraction of disturbed ETGs in our sample, suggesting that minor mergers represent the principal mechanism driving the observed star formation activity in our sample. The young stellar components forming in these events have ages between 0.03 and 0.3 Myrs and typically contribute <10% of the stellar mass of the remnant. Together with recent work which demonstrates that the structural evolution of nearby ETGs is consistent with one or more minor mergers, our results indicate that the overall evolution of massive ETGs may be heavily influenced by minor merging at late epochs and highlights the need to systematically study this process in future observational surveys.Comment: MNRAS in press (significant revisions to version 1

Supernova Shock Breakout from a Red Supergiant

Massive stars undergo a violent death when the supply of nuclear fuel in their cores is exhausted, resulting in a catastrophic "core-collapse" supernova. Such events are usually only detected at least a few days after the star has exploded. Observations of the supernova SNLS-04D2dc with the Galaxy Evolution Explorer space telescope reveal a radiative precursor from the supernova shock before the shock reached the surface of the star and show the initial expansion of the star at the beginning of the explosion. Theoretical models of the ultraviolet light curve confirm that the progenitor was a red supergiant, as expected for this type of supernova. These observations provide a way to probe the physics of core-collapse supernovae and the internal structures of their progenitor starsComment: Science, in press. 32 pages, 7 figure

Spectral Evidence for Emergent Order in Ba1−x_{1-x}Nax_xFe2_2As2_2

We report an angle-resolved photoemission spectroscopy study of the iron-based superconductor family, Ba$_{1-x}$Na$_x$Fe$_2$As$_2$. This system harbors the recently discovered double-Q magnetic order appearing in a reentrant C$_4$ phase deep within the underdoped regime of the phase diagram that is otherwise dominated by the coupled nematic phase and collinear antiferromagnetic order. From a detailed temperature-dependence study, we identify the electronic response to the nematic phase in an orbital-dependent band shift that strictly follows the rotational symmetry of the lattice and disappears when the system restores C$_4$ symmetry in the low temperature phase. In addition, we report the observation of a distinct electronic reconstruction that cannot be explained by the known electronic orders in the system