Response of the West African Monsoon to the Madden–Julian Oscillation

Observations show that rainfall over West Africa is influenced by the Madden-Julian Oscillation (MJO). A number of mechanisms have been suggested: 1) forcing by equatorial waves; 2) enhanced monsoon moisture supply; and 3) increased African easterly wave (AEW) activity. However, previous observational studies are not able to unambiguously distinguish between cause and effect. Carefully designed model experiments are used to assess these mechanisms. Intraseasonal convective anomalies over West Africa during the summer monsoon season are simulated in an atmosphere-only global circulation model as a response to imposed sea surface temperature (SST) anomalies associated with the MJO over the equatorial warm pool region. 1) Negative SST anomalies stabilize the atmosphere leading to locally reduced convection. The reduced convection leads to negative midtropospheric latent heating anomalies that force dry equatorial waves. These waves propagate eastward (Kelvin wave) and westward (Rossby wave), reaching Africa approximately 10 days later. The associated negative temperature anomalies act to destabilize the atmosphere, resulting in enhanced monsoon convection over West and central Africa. The Rossby waves are found to be the most important component, with associated westward-propagating convective anomalies over West Africa. The eastward-propagating equatorial Kelvin wave also efficiently triggers convection over the eastern Pacific and Central America, consistent with observations. 2) An increase in boundary layer moisture is found to occur as a result of the forced convective anomalies over West Africa rather than a cause. 3) Increased shear on the African easterly jet, leading to increased AEW activity, is also found to occur as a result of the forced convective anomalies in the model

Decision model for U.S.-Mexico border security measures

The Department of Homeland Security (DHS) has invested billions of dollars to prevent illegal drugs, immigration, weapons, and currency from transiting across the U.S.–Mexico border. DHS has not created a sufficient standardized method to measure whether an investment in a security measure is cost-effective when combining assets. To take it one step further, DHS has not created a model that combines cost-effectiveness of a security asset while simultaneously determining how it will contribute to achieving operational control of the border. This study provides an in-depth look into the current risk-based model DHS uses, the administrative and physical infrastructure of U.S.-Mexico border security, and a critical view of DHS’ annual budget. A decision model is presented that will give policymakers a process to choose a combination of border security investments that will achieve operational control of the border while remaining within budgeting constraints. A lot of work needs to be done for DHS to determine the correct security assets to be placed at the U.S.-Mexico Border to maintain operational control and cost-effectiveness. This study does not determine which security assets need to be put into place, but it provides a decision process that will be an asset for policymakers to save federal time and money assigned to border security investments.http://archive.org/details/decisionmodelfor1094556150Lieutenant, United States NavyApproved for public release; distribution is unlimited

Cruise Report C-203 : Scientific data collected aboard SSV Corwith Cramer, Key West – Roatan, Honduras – Key West, 8 February 2006 – 18 March 2006

Key West – Roatan, Honduras – Key West, 8 February 2006 – 18 March 2006This cruise report provides a record of data collected aboard the SSV Corwith Cramer during cruise C-203 (U.S. State Department Cruise 2005-096), which departed from Key West, FL on 8 February 2006 and transited through the Florida Straits, the Sargasso Sea, and the Caribbean Sea before returning to Key West on 18 March 2006 (Figure 1). During the six week voyage we collected samples or data at 84 discrete oceanographic stations (Table 1), surface samples at 110 locations (Table 2), and we continuously sampled water depth and sub-bottom profiles (CHIRP system), upper ocean currents (Acoustic Doppler Current Profiler, or ADCP), and sea surface temperature, salinity and in vivo fluorescence (seawater flow-through system). This report summarizes sea surface chemical and biological characteristics (Tables 2 and 3), chemical properties with depth (Table 4), and surface sediment properties (Table 5). Lengthy CTD, CHIRP, ADCP, and flow-through data are not reported here. All unpublished data can be made available by arrangement with the Sea Education Association (SEA) data archivist (contact information, p. 2). The information in this report is not intended to represent final interpretation of the data and should not be excerpted or cited without written permission from SEA. As part of SEA’s educational program, students conduct oceanographic research at sea for studies they have designed prior to the cruise. Student projects span the four major disciplines of oceanography – physical, chemical, biological, and geological oceanography (Table 6). Student research efforts culminate in a written paper and an oral presentation to the ship’s company. The student research papers from cruise C-203 are available upon request from SEA.NS

Declarative Scheduling for Active Objects

International audienceActive objects are programming constructs that abstract dis- tribution and help to handle concurrency. In this paper, we extend the multiactive object programming model to offer a priority specification mechanism. This mechanism allows programmers to have control on the scheduling of requests. The priority representation is based on a dependency graph which makes it very convenient to use. This article shows how to use this mechanism from the programmer side, and exposes the main properties of the dependency graph. The software architecture of our implementation is also presented, as it can be applied to various scheduling systems. Finally, we validate our approach through a microbenchmark that shows that the overhead of our priority representation is rather low. On the whole, we provide a general pattern to introduce a prioritized scheduling in active objects or in any other con- current systems. The resulting framework is shown to be fine-grained, user-friendly, and efficient

Production, use, and fate of all plastics ever made

© The Author(s), 2017. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Science Advances 3 (2017): e1700782, doi:10.1126/sciadv.1700782.Plastics have outgrown most man-made materials and have long been under environmental scrutiny. However, robust global information, particularly about their end-of-life fate, is lacking. By identifying and synthesizing dispersed data on production, use, and end-of-life management of polymer resins, synthetic fibers, and additives, we present the first global analysis of all mass-produced plastics ever manufactured. We estimate that 8300 million metric tons (Mt) as of virgin plastics have been produced to date. As of 2015, approximately 6300 Mt of plastic waste had been generated, around 9% of which had been recycled, 12% was incinerated, and 79% was accumulated in landfills or the natural environment. If current production and waste management trends continue, roughly 12,000 Mt of plastic waste will be in landfills or in the natural environment by 2050.R.G. was supported by the NSF Chemical, Bioengineering, Environmental and Transport Systems grant #1335478

Fluorescent analysis of photosynthetic microbes and Polycyclic Aromatic Hydrocarbons linked to optical remote sensing

Fluorescence analysis, being a non-invasive technique, has become one of the most powerful and widely used techniques for microbiologists and chemists to study various types of sample from photosynthetic microbes to hydrocarbons. The work reported here focuses on experimental results of fluorescent features of photosynthetic microbial species (cyanobacteria) and also five different crude oil samples. The cyanobacteria samples were collected from the Baltic Sea at the end of July 2011 and were associated with cyanobacterial bloom events, and the crude oil samples were from various oil spill events. The aim of the study was to find fluorescent biosignatures of cyanobacteria (initially a species specific to the Baltic Sea) and the fingerprints of crude oil; oil spills can be difficult to differentiate from biogenic films when using Synthetic Aperture Radar (SAR) or sunglint contaminated optical imagery. All samples were measured using a Perkin Elmer LS55 Luminescence spectrometer over a broad range of excitation and emission wavelength from ultraviolet (UV) to near infrared (NIR). The results are presented in Excitation Emission Matrices (EEMs) that exhibit the fluorescent features of each sample. In the EEM of the seawater sample containing cyanobacteria, there is an intense emission peak from tryptophan with fluorescent excitation and emission peaks at 285 and 345 nm respectively. In addition, fluorescent signatures of phycocyanin and chlorophyll-a are present with excitation and emission centre wavelengths at 555 nm, 645 nm and 390 nm, 685 nm, respectively. Additionally, the fluorescence signatures of Polycyclic Aromatic Hydrocarbons (PAHs) are present in the EEMs of crude oil samples with excitation and emission peaks at 285 nm and 425 nm. This study underpins further research on how to distinguish cyanobacteria species by their fluorescence signatures and the potential role that PAHs play in detection of cyanobacteria fluorescence features

Ontogenetic Investigation of Underwater Hearing Capabilities in Loggerhead Sea Turtles (Caretta caretta) Using a Dual Testing Approach

Sea turtles reside in different acoustic environments with each life history stage and may have different hearing capacity throughout ontogeny. For this study, two independent yet complementary techniques for hearing assessment, i.e. behavioral and electrophysiological audiometry, were employed to (1) measure hearing in post-hatchling and juvenile loggerhead sea turtles Caretta caretta (19-62 cm straight carapace length) to determine whether these migratory turtles exhibit an ontogenetic shift in underwater auditory detection and (2) evaluate whether hearing frequency range and threshold sensitivity are consistent in behavioral and electrophysiological tests. Behavioral trials first required training turtles to respond to known frequencies, a multi-stage, time-intensive process, and then recording their behavior when they were presented with sound stimuli from an underwater speaker using a two-response forced-choice paradigm. Electrophysiological experiments involved submerging restrained, fully conscious turtles just below the air-water interface and recording auditory evoked potentials (AEPs) when sound stimuli were presented using an underwater speaker. No significant differences in behavior-derived auditory thresholds or AEP-derived auditory thresholds were detected between post-hatchling and juvenile sea turtles. While hearing frequency range (50-1000/1100 Hz) and highest sensitivity (100-400 Hz) were consistent in audiograms pooled by size class for both behavior and AEP experiments, both post-hatchlings and juveniles had significantly higher AEP-derived than behavior-derived auditory thresholds, indicating that behavioral assessment is a more sensitive testing approach. The results from this study suggest that post-hatchling and juvenile loggerhead sea turtles are low-frequency specialists, exhibiting little differences in threshold sensitivity and frequency bandwidth despite residence in acoustically distinct environments throughout ontogeny

Noxious weed monitoring at the U.S. Air Force Academy: year 4 results

Prepared for: U.S. Air Force Academy, Dept. of Natural Resources.August 15, 2009.Includes bibliographical references

An assessment of high touch object cleaning thoroughness using a fluorescent marker in two Australian hospitals

An Unassigned Group, An Unassigned DepartmentFull Tex

How does Labrador Sea Water enter the deep western boundary current?

Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 968-983, doi:10.1175/2007JPO3807.1.Labrador Sea Water (LSW), a dense water mass formed by convection in the subpolar North Atlantic, is an important constituent of the meridional overturning circulation. Understanding how the water mass enters the deep western boundary current (DWBC), one of the primary pathways by which it exits the subpolar gyre, can shed light on the continuity between climate conditions in the formation region and their downstream signal. Using the trajectories of (profiling) autonomous Lagrangian circulation explorer [(P)ALACE] floats, operating between 1996 and 2002, three processes are evaluated for their role in the entry of Labrador Sea Water in the DWBC: 1) LSW is formed directly in the DWBC, 2) eddies flux LSW laterally from the interior Labrador Sea to the DWBC, and 3) a horizontally divergent mean flow advects LSW from the interior to the DWBC. A comparison of the heat flux associated with each of these three mechanisms suggests that all three contribute to the transformation of the boundary current as it transits the Labrador Sea. The formation of LSW directly in the DWBC and the eddy heat flux between the interior Labrador Sea and the DWBC may play leading roles in setting the interannual variability of the exported water mass.We are also grateful to the NSF for their support of this research