MULCH EFFECTS ON AVOCADO ROOT ROT

Abstract Hass avocado on three types of rootstock (Duke 7, Thomas, and Toro Canyon) and Zutano seedlings were planted in root rot infested soil and treated (or untreated) with mulch, Aliette or gypsum, as well as all possible combinations. Toro Canyon rootstocks produced the largest trees, Duke 7 the smallest. Mulch and gypsum did not affect tree size, however Aliette stimulated tree growth. Mulched trees had increased diseased symptoms while Aliette-treated trees were less symptomatic. Gypsum had no effect on disease ratings

Possible Interruption of Malaria Transmission, Highland Kenya, 2007–2008

Annual insecticide spraying and artemisinin combination therapy may stop transmission

Fitness consequences of Anopheles gambiae population hybridization

BACKGROUND: The use of transgenic mosquitoes with parasite inhibiting genes has been proposed as an integral strategy to control malaria transmission. However, release of exotic transgenic mosquitoes will bring in novel alleles along with parasite-inhibiting genes that may have unknown effects on native populations. Thus it is necessary to study the effects and dynamics of fitness traits in native mosquito populations in response to the introduction of novel genes. This study was designed to evaluate the dynamics of fitness traits in a simulation of introduction of novel alleles under laboratory conditions using two strains of Anopheles gambiae: Mbita strain from western Kenya and Ifakara strain from Tanzania. METHODS: The dynamics of fitness traits were evaluated under laboratory conditions using the two An. gambiae strains. These two geographically different strains were cross-bred and monitored for 20 generations to score fecundity, body size, blood-meal size, larval survival, and adult longevity, all of which are important determinants of the vector's potential in malaria transmission. Traits were analysed using pair-wise analysis of variance (ANOVA) for fecundity, body size, and blood-meal size while survival analysis was performed for larval survival and adult longevity. RESULTS: Fecundity and body size were significantly higher in the progeny up to the 20(th )generation compared to founder strains. Adult longevity had a significantly higher mean up to the 10(th )generation and average blood-meal size was significantly larger up to the 5(th )generation, indicating that hybrids fitness is enhanced over that of the founder strains. CONCLUSION: Hybridization of the two mosquito populations used in this study led to increased performance in the fitness traits studied. Given that the studied traits are important determinants of the vector's potential to transmit malaria, these results suggest the need to release genetically modified mosquitoes that have the same or very similar backgrounds to the native populations

Surface freshening in the Arctic Ocean's Eurasian Basin : an apparent consequence of recent change in the wind-driven circulation

Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 116 (2011): C00D03, doi:10.1029/2011JC006975.Data collected by an autonomous ice-based observatory that drifted into the Eurasian Basin between April and November 2010 indicate that the upper ocean was appreciably fresher than in 2007 and 2008. Sea ice and snowmelt over the course of the 2010 drift amounted to an input of less than 0.5 m of liquid freshwater to the ocean (comparable to the freshening by melting estimated for those previous years), while the observed change in upper-ocean salinity over the melt period implies a freshwater gain of about 0.7 m. Results of a wind-driven ocean model corroborate the observations of freshening and suggest that unusually fresh surface waters observed in parts of the Eurasian Basin in 2010 may have been due to the spreading of anomalously fresh water previously residing in the Beaufort Gyre. This flux is likely associated with a 2009 shift in the large-scale atmospheric circulation to a significant reduction in strength of the anticyclonic Beaufort Gyre and the Transpolar Drift Stream.This work was funded by the National Science Foundation Office of Polar Programs Arctic Sciences Section under awards ARC‐0519899, ARC‐0856479, and ARC‐ 0806306

The Dynamics and Impact of Ocean Acidification and Hypoxia: Insights from Sustained Investigations in the Northern California Current Large Marine Ecosystem

Coastal upwelling ecosystems around the world are defined by wind-generated currents that bring deep, nutrient-rich waters to the surface ocean where they fuel exceptionally productive food webs. These ecosystems are also now understood to share a common vulnerability to ocean acidification and hypoxia (OAH). In the California Current Large Marine Ecosystem (CCLME), reports of marine life die-offs by fishers and resource managers triggered research that led to an understanding of the risks posed by hypoxia. Similarly, unprecedented losses from shellfish hatcheries led to novel insights into the coastal expression of ocean acidification. Partnership for Interdisciplinary Studies of Coastal Oceans (PISCO) scientists and other researchers in the CCLME responded to the rise of OAH with new ocean observations and experiments. This work revealed insights into the expression of OAH as coupled environmental stressors, their temporal and spatial variability, and impacts on species, ecological communities, and fisheries. Sustained investigations also deepened the understanding of connections between climate change and the intensification of hypoxia, and are beginning to inform the ecological and eco-evolutionary processes that can structure responses to the progression of ocean acidification and other pathways of global change. Moreover, because the severity of the die-offs and hatchery failures and the subsequent scientific understanding combined to galvanize public attention, these scientific advances have fostered policy advances. Across the CCLME, policymakers are now translating the evolving scientific understanding of OAH into new management actions

Wind-driven inner-shelf circulation off central Oregon during summer

Velocity measurements from 17 deployments of moored acoustic Doppler current profilers obtained during four summer upwelling seasons are used to describe the crossshelf divergence of Ekman transport in the inner shelf off Oregon. For each deployment the measured surface and bottom cross-shelf transports were compared with estimates of the theoretical Ekman transports to find the fraction of full theoretical Ekman transport present. In general, in 15 m of water at 1–2 km offshore, measured transport was 25% of the full Ekman transport. Measured transports reached full Ekman transport 5–6 km offshore in 50 m of water. This result indicates that the region of active upwelling marked by the divergence of Ekman transport was limited to a narrow region along the coast. With small wind stress curl and no major headlands in the region, no along-shelf trends in the transport fractions were observed. Average transport fractions at each station were similar from year to year with one exception. The interannual variability seen at this particular site was most likely a result of local along-shelf bathymetric features. In addition, a weak linear relationship was found between the ambient stratification and the fraction of full Ekman transport. Reduced cross-shelf transport occurred at times of decreased stratification. This type of ‘‘shutdown’’ of the inner-shelf cross-shelf circulation has significant biological implications, sequestering production in the nearshore and reducing larval cross-shelf transport

Combined electroejaculation and in vitro fertilization in the evaluation and treatment of anejaculatory infertility

Seven couples underwent combined electroejaculation and in vitro fertilization for anejaculatory infertility after a failed regimen of electroejaculation and intrauterine insemination. Two pregnancies resulted, one proceeding to a term vaginal delivery and one ending in a 6-week spontaneous abortion. Poor sperm binding and no fertilization were seen in two of the couples. Fertilization of the oocytes but no subsequent pregnancy were seen in the other three couples. Combined in vitro fertilization and gamete intrafallopian transfer was performied in four of the couples. The combination of electroejaculation and in vitro fertilization offers the opportunity to evaluate the female pelvis, observe the sperm-oocyte interaction, and achieve a pregnancy in couples with anejaculatory infertility.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44644/1/10815_2005_Article_BF01133886.pd

Intercomparison of snow depth retrievals over Arctic sea ice from radar data acquired by Operation IceBridge

Since 2009, the ultra-wideband snow radar on Operation IceBridge (OIB; a NASA airborne mission to survey the polar ice covers) has acquired data in annual campaigns conducted during the Arctic and Antarctic springs. Progressive improvements in radar hardware and data processing methodologies have led to improved data quality for subsequent retrieval of snow depth. Existing retrieval algorithms differ in the way the air–snow (a–s) and snow–ice (s–i) interfaces are detected and localized in the radar returns and in how the system limitations are addressed (e.g., noise, resolution). In 2014, the Snow Thickness On Sea Ice Working Group (STOSIWG) was formed and tasked with investigating how radar data quality affects snow depth retrievals and how retrievals from the various algorithms differ. The goal is to understand the limitations of the estimates and to produce a well-documented, long-term record that can be used for understanding broader changes in the Arctic climate system. Here, we assess five retrieval algorithms by comparisons with field measurements from two ground-based campaigns, including the BRomine, Ozone, and Mercury EXperiment (BROMEX) at Barrow, Alaska; a field program by Environment and Climate Change Canada at Eureka, Nunavut; and available climatology and snowfall from ERA-Interim reanalysis. The aim is to examine available algorithms and to use the assessment results to inform the development of future approaches. We present results from these assessments and highlight key considerations for the production of a long-term, calibrated geophysical record of springtime snow thickness over Arctic sea ice