Panama City Research Articles

Research and Conservation on an Artificial Island in a Shipping Lane and Elsewhere in the Tropics

Research and Conservation on an Artificial Island in a Shipping Lane and Elsewhere in the Tropics

A hurricane surge risk assessment framework using the joint probability method and surge response functions

Hurricane surge events have caused devastating damage in active-hurricane areas all over the world. The ability to predict surge elevations and to use this information for damage estimation is fundamental for saving lives and protecting property. In this study, we developed a framework for evaluating hurricane flood risk and identifying areas that are more prone to them. The approach is based on the joint probability method with optimal sampling (JPM-OS) using surge response functions (SRFs) (JPM-OS-SRF). Derived from a discrete set of high-fidelity storm surge simulations, SRFs are non-dimensional, physics-based empirical equations with an algebraic form, used to rapidly estimate surge as a function of hurricane parameters (i.e., central pressure, radius, forward speed, approach angle and landfall location). The advantage of an SRF-based approach is that a continuum of storm scenarios can be efficiently evaluated and used to estimate continuous probability density functions for surge extremes, producing more statistically stable surge hazard assessments without adding measurably to epistemic uncertainty. SRFs were developed along the coastline and then used to estimate maximum surge elevations with respect to a set of hurricane parameters. Integrating information such as ground elevation, property value and population with the JPM-OS-SRF allows quantification of storm surge-induced hazard impacts over the continuum of storm possibilities, yielding a framework to create the following risk-based products, which can be used to assist in hurricane hazard management and decision making: (1) expected annual loss maps; (2) flood damage versus return period relationships; and (3) affected business (e.g., number of business, number of employees) versus return period relationships. By employing several simplifying assumptions, the framework is demonstrated at three northern Gulf of Mexico study sites exhibiting similar surge hazard exposure. The framework results reveal Gulfport, MS, USA is at relatively more risk of economic loss than Corpus Christi, TX, USA, and Panama City, FL, USA. Note that economic processes are complex and very interrelated to most other human activities. Our intention here is to present a methodology to quantify the flood damage (i.e., infrastructure economic loss, number of businesses affected, number of employees in these affected businesses and sales volume in these affected businesses) but not to discuss the complex interactions of these damages with other economic activities and recovery plans.

Isolation of Candida auris from 9 patients in Central America: Importance of accurate diagnosis and susceptibility testing.

Candida auris is an emerging multidrug-resistant (MDR) fungus associated with invasive infections and high mortality. This report describes 9 patients from whom C.auris was isolated at a hospital in Panama City, Panama, the first such cases in Central America, and highlights the challenges of accurate identification and methods for susceptibility testing.

Characterizing Transmission Loss Variability During the Target and Reverberation Experiment 2013

A significant driver of uncertainty in sonar performance is the variability in underwater acoustical propagation caused by environmental fluctuations and uncertainty in the position of sources, targets, and receivers. A set of echo-repeat experiments was conducted during the Target and Reverberation Experiment 2013 (TREX13), a sea trial that took place in April to May 2013 in the Gulf of Mexico near Panama City, FL, USA. The variability in measured transmission loss (TL) was characterized using two different methods: Variability with respect to a mean observed TL, and variability with respect to modeled TL. Both one-way and quasi-reciprocal two-way TL measurements at 2250 and 7500 Hz were analyzed to characterize the variability at timescales ranging from less than one second to several days, with the results indicating that the acoustic propagation fluctuates stochastically on all these time scales. The results of statistical tests suggest that the TL variability can be treated as Gaussian fluctuations about a central TL obtained from an acoustic propagation model, with standard deviations of 5 dB over timescales up to one day, or 10 dB over timescales from one to six days.

Direct Measurements of Sediment Sound Speed and Attenuation in the Frequency Band of 2–8 kHz at the Target and Reverberation Experiment Site

The sediment acoustic-speed measurement system is designed to measure in situ sediment sound speed and attenuation within the surficial 3 m of sediments in the frequency band of 2–8 kHz. Measurements were carried out during the Target and Reverberation EXperiment 2013 (TREX13) off Panama City, FL, USA. During TREX13, nine deployments at five selected sites were made along the 20-m isobath, termed the main reverberation track. The sediment types at the five selected sites ranged from coarse sand to a mixture of soft mud over sand, and the measured results show a spread of 80 m/s in sediment sound speed among the different types of sediments for all frequencies. Between 2–8 kHz, about 3% dispersion was observed at the sandy sites, whereas little dispersion was observed at the sites with mud. Preliminary attenuation results show 0.5–3.3 dB/m at the sandy sites, and 0.5–1.0 dB/m at the sites with mud in the same frequency band.

Observations of Water Column and Bathymetric Effects on the Incident Acoustic Field Associated With Shallow-Water Reverberation Experiments

As a part of the 2013 Targets and Reverberation Experiment (TREX13), measurements of the acoustic field generated by a source used in midfrequency (1.8–3.6 kHz) reverberation experiments are studied at 5 and 6 km range. The TREX13 reverberation sources were placed off the coast of Panama City, FL, USA, in waters ∼20 m deep, and data discussed here are from a 2-h period in the late afternoon on April 28, 2013. The observed coda of the source signal is partitioned into an initial primary arrival, and a distinct second arrival delayed by roughly 2 s. Characteristics of the two arrivals are studied in terms of the effective number of modes, interference features, and the direction of acoustic intensity, which was directly measured by a vector sensor located at 5 km range. A shift in frequency within the primary arrival is observed over the 2-h measurement period. Frequency shifts are related to a change in range of dislocations, defined as points of complete destructive interference in the acoustic field, that modulate with tidal variation in the sound-speed profile. Precise frequencies are identified with the vector property called circularity, a nondimensional measure of acoustic intensity curl, that is maximal within the vortex-like intensity field within a dislocation. Using the waveguide invariant β, the frequency shift is used to estimate the tidal change in the thermocline depth. These interference features are absent in the second arrival, which is postulated to be an acoustic path horizontally refracted by the gently sloping bathymetry (∼0.4°) forming the coastal environment. A description of the refraction using modal rays is developed, and the transition of the mode from being trapped to leaky is handled as a transition to a virtual mode near the cutoff depth. Models of the primary and refracted arrivals are presented to support the conclusions.

The Background Noise Environment During the 2013 Target and REverberation eXperiment

This paper presents an analysis of the time- and frequency-domain properties of a multiday series of background noise during the Target and REverberation eXperiment (TREX13) that took place off the coast of Panama City, FL, USA. Background noise was measured at two locations approximately 5 and 6 km south-east of the location of the R/V Sharp where monostatic reverberation was measured. The median spectral density level estimated for a frequency band centered at 2.7 kHz with a bandwidth of 1800 Hz was comparable to the median level at 3.5 kHz averaged over a bandwidth of 100 Hz; both were estimated to be 60 dB re 1 $\mu$ Pa $^2$ /Hz when averaged during the day or night. In contrast, the level at 4.5 kHz, estimated by averaging over a bandwidth of 100 Hz, increased by 14 dB at night. While the data suggest a degree of consistency in the background environment for the purposes of modeling, when assessing levels in the 80–8000 Hz frequency band, time of day was found to be influential. The median spectral levels presented may be used to assess the influence of background noise at a given time of day. Biological noise likely from fish was revealed to be a significant contributor to background noise at night, and daytime background noise levels were primarily influenced by wind.

The complete genome sequence of human adenovirus 84, a highly recombinant new Human mastadenovirus D type with a unique fiber gene

A novel human adenovirus was isolated from a pediatric case of acute respiratory disease in Panama City, Panama in 2011. The clinical isolate was initially identified as an intertypic recombinant based on hexon and fiber gene sequencing. Based on the analysis of its complete genome sequence, the novel complex recombinant Human mastadenovirus D (HAdV-D) strain was classified into a new HAdV type: HAdV-84, and it was designated Adenovirus D human/PAN/P309886/2011/84[P43H17F84]. HAdV-D types possess usually an ocular or gastrointestinal tropism, and respiratory association is scarcely reported. The virus has a novel fiber type, most closely related to, but still clearly distant from that of HAdV-36. The predicted fiber is hypothesised to bind sialic acid with lower affinity compared to HAdV-37. Bioinformatic analysis of the complete genomic sequence of HAdV-84 revealed multiple homologous recombination events and provided deeper insight into HAdV evolution.

Quaternary intertidal and supratidal crabs (Decapoda, Brachyura) from tropical America and the systematic affinities of fossil fiddler crabs

Concentrations of fully articulated crabs are rare in the fossil record, especially for terrestrial and semi-terrestrial taxa, which tend to be represented by scarce, fragmentary and poorly preserved fossils due to preservational biases. A newly discovered fossiliferous locality at Bahia Bique, west of Panama City, Panama, yielded a collection of supratidal, intertidal and shallow subtidal invertebrates and vertebrates of mid-Holocene age. Notable discoveries include the first fossils of the sally lightfoot crab Grapsus, the first for the land crab Cardisoma in the Eastern Pacific and, remarkably, the most complete and abundant collection of fossil fiddler crabs, Uca, yet discovered. The abundance and exceptional preservation of fossil male, female, juvenile and adult individuals of Uca aff. ornata in eroded burrow infills suggest that rapid entombment and early diagenesis were crucial for their preservation. The habitat preference of extant U. ornata for soft muds of open intertidal mudflats indicates that part of Bahía Bique must have been a large estuarine mudflat with close proximity to freshwater influx, in contrast to the present-day gravel field where the fossils are found as ex situ boulders, cobbles and gravel-sized clasts eroded from rocks of the poorly known Pacific Muck. We examine the systematic relationships of fossil fiddler crabs from Bahía Bique via synthetic and cladistic approaches, and conclude that they were from an extinct population of the extant Uca ornata. The fidelity of living–death assemblages between the Bique faunule and extant faunas of the tropical Eastern Pacific confirm the Quaternary age of the assemblage, and stimulate a detailed discussion of the preservation and palaeoecology of terrestrial and semi-terrestrial crabs in tropical assemblages.

The 1925 Tenants’ Strike in Panama:West Indians, the Left, and the Labor Movement

In September-October 1925, there occurred in Panama a tenants' strike that helped define the development of the left and workers' movement in that nation. This article presents an overview of the strike—important because no synthetic English-language account exists—and then analyzes the role of black West Indians in the event. West Indians were prominent among the ranks of workers in Panama, and among the slums of Panama City and Colón. Nonetheless, they were not central to the rent strike. This absence reflects the historic relationship between West Indian and Hispanic workers in the isthmus, the effect of the recent defeat of strikes led by West Indians in the Panama Canal Zone, and the lack of attention paid to attracting West Indian support by the Hispanic leadership of the tenants' strike. This division between the West Indian population and the broader labor movement in Panama had lasting effects in the history of the Panamanian left, reinforcing divisions between the struggle for Panamanian self-determination and the struggle against racist oppression of West Indians and their descendants in Panama.

PA/LTC Goes Around the World in Online Communities

PA/LTC Goes Around the World in Online Communities

Soil trace gas fluxes along orthogonal precipitation and soil fertility gradients in tropical lowland forests of Panama

Abstract. Tropical lowland forest soils are significant sources and sinks of trace gases. In order to model soil trace gas flux for future climate scenarios, it is necessary to be able to predict changes in soil trace gas fluxes along natural gradients of soil fertility and climatic characteristics. We quantified trace gas fluxes in lowland forest soils at five locations in Panama, which encompassed orthogonal precipitation and soil fertility gradients. Soil trace gas fluxes were measured monthly for 1 (NO) or 2 (CO2, CH4, N2O) years (2010–2012) using vented dynamic (for NO only) or static chambers with permanent bases. Across the five sites, annual fluxes ranged from 8.0 to 10.2 Mg CO2-C, −2.0 to −0.3 kg CH4-C, 0.4 to 1.3 kg N2O-N and −0.82 to −0.03 kg NO-N ha−1 yr−1. Soil CO2 emissions did not differ across sites, but they did exhibit clear seasonal differences and a parabolic pattern with soil moisture across sites. All sites were CH4 sinks; within-site fluxes were largely controlled by soil moisture, whereas fluxes across sites were positively correlated with an integrated index of soil fertility. Soil N2O fluxes were low throughout the measurement years, but the highest emissions occurred at a mid-precipitation site with high soil N availability. Net negative NO fluxes at the soil surface occurred at all sites, with the most negative fluxes at the low-precipitation site closest to Panama City; this was likely due to high ambient NO concentrations from anthropogenic sources. Our study highlights the importance of both short-term (climatic) and long-term (soil and site characteristics) factors in predicting soil trace gas fluxes.

EJEMPLOS DE MEMORIA, MNEMOTECNIA, PALIMPSESTO E HIPERTEXTO EN PANAMÁ Y EL MUNDO: UNA METODOLOGÍA PARA LA CONSERVACIÓN

En este artículo se analizarán los conceptos de memoria, mnemotecnia, palimpsesto e hipertexto. Sebastien Marot (2003), profesor de la École d’Architecture de la Ville & des Territoires – Marne-la-Vallée (Francia), explica que estos cuatro reflejos son una nueva forma de afrontar un programa de diseño en arquitectura, el cual da prioridad al emplazamiento. Estos mismos conceptos –memoria, mnemotecnia, palimpsesto, hipertexto– están relacionados con la conservación, ya sea en un contexto urbano o arquitectónico. El objetivo de este trabajo es dar ejemplos (en su mayoría en Ciudad de Panamá) de su uso en esta disciplina, y vincular estos reflejos o características a un método para desarrollar un proyecto de conservación. Mediante estos ejemplos se explicará cómo la memoria y la mnemotecnia mantienen el espíritu del lugar, cómo un palimpsesto representa la historia de las transformaciones de un territorio, ciudad o edificio, y cómo ayuda un hipertexto a organizar un proyecto de conservación.

Suez to extend Panama City's wastewater treatment plant

The Ministry of Health of the Republic of Panama (MINSA) has awarded Suez a €195 million contract to build and operate an extension to the Juan Diaz wastewater treatment plant in Panama City.

Historical development of side scan sonar

The seabed mapping side scan sonar, conceived and developed in the 1950s at the U.S. Navy Mine Defense Laboratory (USNMDL) [Commander and Sternlicht, J. Acoust. Soc. Am. 137, 2307 (2015)], was inspired by the Royal Navy ASDIC Type-162, a late-WWII hull mounted side-looking sonar capable of recording the silhouettes of bottomed U-boats. The commissioned U.S. Navy C-MK-1 SHADOWGRAPH, which operated in the Megahertz band and employed curved apertures for cross-track focusing, represents the first in a long history of military and commercial innovations. Commercial side scan sonars, typically operating in the tens or hundreds of Kilohertz, reached the marketplace in the 1960s. The SHADOWGRAPH series led to the Navy’s AN/AQS-14 and French DUBM-series mine detection sonars, and the active tow vehicles of the C-MK-1 served as test platforms for the first synthetic aperture sonars (SAS) fielded at USNMDL (now the Naval Surface Warfare Center Panama City Division) during the 1970s. Through the present day these systems, military and commercial, have been augmented by revolutionary: developments in swath bathymetry side scan sonar, multi-beam echo sounders, and SAS; signal processing advances in acoustic tomography and spectroscopy; and information processing advances in environmental characterization, automatic target recognition and seabed change detection.

Occurrence of the mite Ophionyssus natricis (Acari: Macronyssidae) on captive snakes from Panama

We report for the first time the presence of the snake mite, Ophionyssus natricis (Gervais) (Mesostigmata: Macronyssidae) on captive snakes kept in Panama City, Panama. This occurrence adds a new record to the geographical distribution of O. natricis as well as confirming its high prevalence on captive reptiles. Several Boidae species, Boa constrictor, Epicrates maurus, Corallus ruschenbergerii, Corallus caninus and a Pythonidae, Python regius were found infested with intensities varying from 10 to 2200 mites each. These findings represent the second record of O. natricis for Central America.

Guest Editorial Target and Reverberation Experiment 2013 (TREX13)—Part I

The articles in this special section focus on research and development related to the Target and Reverberation Experiment (TREX13) conducted in the Gulf of Mexico off Panama City, FL, USA, in spring 2013. The primary goal of the experiment was to measure midfrequency (2–10 kHz), shallow-water reverberation with full companion environmental measurements such that models and data could be compared without ambiguity. While a number of other major field efforts, such as the Acoustic Reverberation Special Research Program and the Acoustic Clutter Reconnaissance Experiment, have been conducted to study low- to midfrequency reverberation, it has been difficult to measure and account for all of the relevant reverberation mechanisms in a single experiment.

A Normal Mode Reverberation and Target Echo Model to Interpret Towed Array Data in the Target and Reverberation Experiments

Reverberation measurements obtained with towed arrays are a valuable tool to extract information about the ocean environment. By superimposing a polar plot of reverberation beam time series on bathymetry maps, bottom features (often uncharted) can be located. As part of Rapid Environmental Assessment exercises, Preston and Ellis used directional reverberation measurements to extract environmental information using model-data comparisons. This early work used range-independent (flat bottom) ray-based models for the model-data comparisons, while current work includes range-dependent models based on adiabatic normal modes. Here, we discuss a range-dependent shallow-water reverberation model using adiabatic normal modes that has been developed to handle bottom scattering and clutter echoes in a range-dependent environment. Beam time series similar to those measured on a horizontal line array can be produced. Comparisons can then directly be made with data, features identified, and estimates of the scattering obtained. Of particular interest will be data obtained on the triplet line array during the 2013 Target and Reverberation EXperiments in the Gulf of Mexico off Panama City, FL, USA, where interesting effects in sea bottom sand dunes were observed. Particular attention has been paid to calibration to get estimates of scattering strengths. In addition to the reverberation, a preliminary investigation of the target echo is presented.

Experimental Implementation of an Echo Repeater for Continuous Active Sonar

The 2013 Target and Reverberation Experiment (TREX13) sea trial was held just off the coast of Panama City, FL, USA, in May 2013. One of Defence Research and Development Canada's primary objectives was comparing the performance of continuous active sonar (CAS) and pulsed active sonar (PAS) in shallow water, where reverberation and clutter challenge sonar systems. The only option for a moving target during the trial was an echo repeater towed from a ship; however, this posed a serious challenge because before the trial there were no known echo repeater solutions that were compatible with CAS. Existing echo repeaters required short-duration waveforms as used in PAS, and even then they introduced range errors that caused a mismatch in reverberation background and made localization problematic. This paper presents three echo repeater techniques developed for TREX13 and tested on Canadian Forces Auxiliary research vessel CFAV Quest during the trial. Experimental results presented in this paper demonstrate detection of the echo repeater by a monostatic CAS system on R/V Hugh R Sharp .

Modeling and Observations of Sand Ripple Formation and Evolution During TREX13

Ripples on the seafloor affect acoustic scattering and transmission loss, wave attenuation, and the amount of sediment transported in shallow water. Historically, seafloor roughness (a function of ripples, bedforms, sediment type, and size) is assumed to be spatially homogeneous and temporally static in hydrodynamic and acoustic models despite the often dynamic nature of the seafloor in the nearshore region. We present a spectral ripple model, Navy Seafloor Evolution Archetype (NSEA), which simulates the variations in seafloor roughness given measured or predicted wave conditions in sandy environments. NSEA simulates sand ripple formation and evolution based on bottom velocities either measured or predicted by a wave model. The time dependency is a function of equilibrium ripple geometries and the amount of sediment transport needed to reach an equilibrium state, which is dependent on the relict ripples. Spectral decay due to bioturbation is incorporated as a diffusive process. NSEA was validated with time series observations obtained in water depths of 7.5 and 20 m from April 20, 2013 to May 23, 2013 during the 2013 Target and Reverberation Experiment (TREX13) offshore of Panama City, FL, USA. The model predicted spectral ripple wavelengths that were in good agreement with observed spectral ripple wavelengths obtained using a fixed platform, high-frequency (2.25 MHz) sector scanning sonar. Likewise, the variations in the predicted normalized ripple heights and orientations were similar to the normalized spectral decay and orientations estimated from the sector scanning sonar imagery.