Risk factors for house-entry by malaria vectors in a rural town and satellite villages in The Gambia.

Background: In the pre-intervention year of a randomized controlled trial investigating the protective effects of house screening against malaria-transmitting vectors, a multi-factorial risk factor analysis study was used to identify factors that influence mosquito house entry. Methods: Mosquitoes were sampled using CDC light traps in 976 houses, each on one night, in Farafenni town and surrounding villages during the malaria-transmission season in The Gambia. Catches from individual houses were both (a) left unadjusted and (b) adjusted relative to the number of mosquitoes caught in four sentinel houses that were operated nightly throughout the period, to allow for night-to-night variation. Houses were characterized by location, architecture, human occupancy and their mosquito control activities, and the number and type of domestic animals within the compound. Results: 106,536 mosquitoes were caught, of which 55% were Anopheles gambiae sensu lato, the major malaria vectors in the region. There were seven fold higher numbers of An. gambiae s.l. in the villages (geometric mean per trap night = 43.7, 95% confidence intervals, CIs = 39.5–48.4) than in Farafenni town (6.3, 5.7–7.2) and significant variation between residential blocks (p < 0.001). A negative binomial multivariate model performed equally well using unadjusted or adjusted trap data. Using the unadjusted data the presence of nuisance mosquitoes was reduced if the house was located in the town (odds ratio, OR = 0.11, 95% CIs = 0.09–0.13), the eaves were closed (OR = 0.71, 0.60–0.85), a horse was tethered near the house (OR = 0.77, 0.73–0.82), and churai, a local incense, was burned in the room at night (OR = 0.56, 0.47–0.66). Mosquito numbers increased per additional person in the house (OR = 1.04, 1.02–1.06) or trapping room (OR = 1.19, 1.13–1.25) and when the walls were made of mud blocks compared with concrete (OR = 1.44, 1.10–1.87). Conclusion: This study demonstrates that the risk of malaria transmission is greatest in rural areas, where large numbers of people sleep in houses made of mud blocks, where the eaves are open, horses are not tethered nearby and where churai is not burnt at night. These factors need to be considered in the design and analysis of intervention studies designed to reduce malaria transmission in The Gambia and other parts of sub-Saharan Africa

Role of Schizosaccharomyces pombe RecQ homolog recombination and checkpoint genes in UV Damage tolerance

The cellular responses to DNA damage are complex and include direct DNA repair pathways that remove the damage and indirect damage responses which allow cells to survive DNA damage that has not been, or cannot be, removed. We have identified the gene mutated in the rad12.502 strain as a Schizosaccharomyces pombe recQ homolog. The same gene (designated rqh1) is also mutated in the hus2.22 mutant. We show that Rqh1 is involved in a DNA damage survival mechanism which prevents cell death when UV-induced DNA damage cannot be removed. This pathway also requires the correct functioning of the recombination machinery and the six checkpoint tad gene products plus the Cds1 kinase. Our data suggest that Rqh1 operates during S phase as part of a mechanism which prevents DNA damage causing cell lethality. This process may involve the bypass of DNA damage sites by the replication fork. Finally, in contrast with the reported literature, we do not find that rqh1 (rad12) mutant cells are defective in UV dimer endonuclease activity

Southern expansion of the brown alga Colpomenia peregrina Sauvageau (Scytosiphonales) in the Northwest Atlantic Ocean

Blackler first recorded Colpomenia peregrina in the Northwest Atlantic based on collections from Nova Scotia, Canada. Five decades later we found large quantities of C. peregrina in Maine, USA, even though it was absent during earlier floristic studies in this region. Thus, C. peregrina has undergone a rapid southern expansion along the Northwest Atlantic coast. While the causes of such an expansion are unknown, it could have a major effect on both shellfish cultivation and native seaweeds within New England because of competitive interactions and increased drag

Infiltration and short-term movement of nitrogen in a silt-loam soil typical of rice cultivation in Arkansas

Rice production in Arkansas is one of the top three crop commodities in terms of cash receipts. Researchers and farmers report that nitrogen (N) needs to be managed according to a variety of factors with two important ones being soil and fertilizer type. The objectives of this experiment were to determine: 1) the degree to which floodwater-incorporated N applied as urea or as ammonium sulfate infiltrates intact cores (7.2-cm dia., 10-cm depth) containing DeWitt siltloam soil, and 2) the distribution of N during 12 h of ponding. Inorganic-N concentrations were analyzed at 2-cm depth intervals in cores following removal of the flood. Nitrogen from applied fertilizer was recovered as ammonium. Ammonium sulfate-N remained in the top 4 cm of soil with concentrations of 375 µg N g-1 in the surface 2 cm and 300 µg N g-1 at the 2 - 4 cm depth after 12 hr of ponding. At all depth intervals below 4 cm, ammonium sulfate-N remained below 30 µg N g-1. In contrast, after 12 h of ponding, N in soil receiving urea was 105 µg N g-1 in the top 2 cm and 173 µg N g-1 at 2-4 cm. At 4-6, 6-8, and 8-10 cm, N was 109, 108, and 35 µg N g-1, respectively, after 12 h of ponding. These results demonstrate immediate and deeper movement of ammonium into silt loam soil receiving urea as compared to ammonium sulfate, demonstrating how the form of N in fertilizer affects its movement into the soil profile

Structural studies of hydrated samples of amorphous calcium phosphate and phosphoprotein nanoclusters

There are abundant examples of nanoclusters and inorganic microcrystals in biology. Their study under physiologically relevant conditions remains challenging due to their heterogeneity, instability, and the requirements of sample preparation. Advantages of using neutron diffraction and contrast matching to characterize biomaterials are highlighted in this article. We have applied these and complementary techniques to search for nanocrystals within clusters of calcium phosphate sequestered by bovine phosphopeptides, derived from osteopontin or casein. The neutron diffraction patterns show broad features that could be consistent with hexagonal hydroxyapatite crystallites smaller than 18.9 Å. Such nanocrystallites are, however, undetected by the complementary X-ray and FTIR data, collected on the same samples. The absence of a distinct diffraction pattern from the nanoclusters supports the generally accepted amorphous calcium phosphate structure of the mineral core

Mid-IR continuous-wave fiber-laser-pumped optical parametric oscillators

We review recent developments in continuous-wave mid-infrared optical parametric oscillators pumped by fiber lasers. Such devices are potentially valuable spectroscopic sources providing high output powers and rapid, wide-range tuning in the mid-infrared molecular fingerprint region

Climate Science, Development Practice, and Policy Interactions in Dryland Agroecological Systems

The literature on drought, livelihoods, and poverty suggests that dryland residents are especially vulnerable to climate change. However, assessing this vulnerability and sharing lessons between dryland communities on how to reduce vulnerability has proven difficult because of multiple definitions of vulnerability, complexities in quantification, and the temporal and spatial variability inherent in dryland agroecological systems. In this closing editorial, we review how we have addressed these challenges through a series of structured, multiscale, and interdisciplinary vulnerability assessment case studies from drylands in West Africa, southern Africa, Mediterranean Europe, Asia, and Latin America. These case studies adopt a common vulnerability framework but employ different approaches to measuring and assessing vulnerability. By comparing methods and results across these cases, we draw out the following key lessons: (1) Our studies show the utility of using consistent conceptual frameworks for vulnerability assessments even when quite different methodological approaches are taken; (2) Utilizing narratives and scenarios to capture the dynamics of dryland agroecological systems shows that vulnerability to climate change may depend more on access to financial, political, and institutional assets than to exposure to environmental change; (3) Our analysis shows that although the results of quantitative models seem authoritative, they may be treated too literally as predictions of the future by policy makers looking for evidence to support different strategies. In conclusion, we acknowledge there is a healthy tension between bottom-up/ qualitative/place-based approaches and top-down/quantitative/generalizable approaches, and we encourage researchers from different disciplines with different disciplinary languages, to talk, collaborate, and engage effectively with each other and with stakeholders at all levels

In the Right Ballpark? Assessing the Accuracy of Net Price Calculators

Large differences often exist between a college’s sticker price and net price after accounting for financial aid. Net price calculators (NPCs) were designed to help students more accurately estimate their actual costs to attend a given college. This study assesses the accuracy of information provided by net price calculators. Specifically, we compare NPC estimates of financial aid to actual aid packages for a sample of low-income, first-time college students at seven postsecondary institutions which all utilize the federal template NPC. We find that NPC estimates of grant aid correlate highly with actual grant aid on average, but variation in individual financial aid packages among socioeconomically similar students can be substantial. We offer four recommendations. First, NPC aid estimates should include information on variability, and potentially, on sources of that variability. Second, a basic metric of academic merit such as SAT/ACT scores and GPA should be an optional addition to the federal template NPC. Third, institutions should update the data underlying their NPCs annually. Finally, we recommend that institutions use the “Explanations and Caveats” options on the federal NPC template to include additional information that may be helpful for students and families in anticipating their likely college aid and expenses. Our findings have implications for federal policy related to NPCs