Post Hurricane Research Articles

Component and Cladding Wind Loads for Soffits

The wind induced failure of soffits of low rise structures is a failure mechanism commonly observed in post hurricane damage investigations. The failure of the soffits has the potential to allow both wind and water to enter the attic space of the building. The current US national wind loading standard (ASCE 7) provides no guidance as to the wind load requirements for the design of soffits. In order to address this deficiency, wind tunnel tests on 1:50 scale models of one-, two-, and three-story hip and gable roof buildings were performed where measurements of the wind induced pressures and suctions on the soffits, roofs, and walls were obtained. The wind tunnel tests were performed in open and suburban terrain conditions, with and without surrounding buildings in place. The results of the tests clearly show that the soffit pressures are nearly fully correlated with nearby wall pressures, and a simple and accurate solution to the soffit loading deficiency in ASCE 7 is to prescribe that the component and cladding pressures for use in the design of soffits be identical to the component and cladding loads used for the design of wall components.

2007 MURDER RATES IN NEW ORLEANS, LOUISIANA

In an earlier estimation of the murder rate for New Orleans, Louisiana, for 2006, I concluded that the best population data available translated the 162 recorded homicides into a 2006 murder rate of 96.6 per 100000—a record high. An alternative measure of 72.5 per 100 000 can be calculated using the US Census Bureau’s 2006 midyear population estimate of 223 388 for the city.2 This US Census Bureau population estimate for midyear 2006 is much higher than the other systematic and well-documented estimates undertaken during 2006. Well-documented population estimates for 2007 are not available, but voter turnout in the fall 2007 and 2003 elections alongside population extrapolations can provide an upper bound to population size in New Orleans in the fall and summer of 2007 and a lower bound for the 2007 murder rate. If turnout had been the same in both elections, this would imply a maximum New Orleans population of 291045 on October 20, 2007. Backward projection using the growth rate implied by this figure and the US Census Bureau 2006 midyear population estimate provides a maximum (highest plausible) population estimate of 273382 for New Orleans in July 2007. The 209 recorded homicides translate to a minimum murder rate of 76.4 per 100000. If one accepts the low figure of 72.5 for the 2006 murder rate, which many city government leaders do, the murder rate in New Orleans during 2007 was higher than that in 2006 by no less than 5% and higher than that in 2004 (the last full year before Hurricane Katrina) by no less than 34%. The above 2007 population figures should be considered upper-bound estimates for the following reasons: the 2007 election took place in a smaller city (where turnouts are higher3), on a day with perfect weather, with the significance of election outcomes never greater, and with substantial post–Hurricane Katrina demographic shifts toward groups more likely to vote. This estimate, based on the assumption of “no difference in turnout,” resulted in the highest plausible population figures for 2007, and the resulting murder rate is the lowest it plausibly could be. In other words, the true population size is most likely to be lower, and the true murder rate is most likely to be higher. The murder rate for New Orleans remains stubbornly elevated at extraordinarily high levels since Hurricane Katrina and has yet to begin a decline to even prestorm levels, which were very high in the first place.

PDA Use by Undergraduate Nursing Students on Pediatrie Clinical Rotations

In the 2005/2006 academic year, library and nursing faculty at Southeastern Louisiana University (SELU) investigated the use of personal digital assistants (PDAs) in undergraduate nursing instruction. This quasi-experimental research study, funded by the National Network/Libraries of Medicine, South Central Region, describes PDA use in pediatrie clinical instruction at three community hospitals, five health care centers in schools, and unanticipated post Hurricane Katrina use at evacuation shelters and East Baton Rouge Public Schools. The project consisted of acquiring hardware and clinical software, instruction in PDA use, development of library procedures for managing equipment, evaluation and analysis, and interdisciplinary collaboration between library and nursing faculty.

Robert W. Woodruff Library of the Atlanta University Center, Custodian of the Morehouse College Martin Luther King, Jr. Collection: “Until Further Notice”

On June 23, 2006, the American Library Association was holding its Annual Conference in New Orleans, Louisiana, the first major conference to return to the city post Hurricane Katrina. My scheduled visit of four days was abruptly cut short as a result of two communications: a call from Walter Massey, President of More-house College in Atlanta, Georgia, and an e-mail from William Potter, Dean of the University of Georgia Libraries. By the time the day was over, I learned that a collection of manuscripts and books documenting many of the writings, speeches, and notes of Dr. Martin Luther King, Jr. . . .

Optics, particles, stratification, and storms on the New England continental shelf

In situ beam attenuation and chlorophyll fluorescence were correlated with concentration and bulk composition of particles in shelf waters during summer and spring under different physical forcing conditions to determine if optical parameters could be used as an additional tracer in examining the process of mixing in shelf waters. Time series measurements were made for two 18 day periods during high stratification (late summer 1996, Δσt = ∼3.0 kg m−3 surface to bottom) and low but rapidly developing stratification (spring 1997, Δσt = 0.05 to 0.5 kg m−3) in 70 m of water in a midshelf environment south of Martha's Vineyard, Massachusetts. When defined by hydrography and optical profiles, four layers were identified during the summer: the surface mixed layer, the particle/chlorophyll maximum, the midwater particle minimum, and the bottom nepheloid layer. Fast moving solitons perturbed the water column briefly, but no storms perturbed the system until large surface swells from Hurricane Edouard intensified and thickened the nepheloid layer. Bulk composition and optics of particles in and above the nepheloid layer were distinctly different after the passage of Hurricane Edouard. The hurricane passage demonstrated that intense atmospheric forcing greatly influences both hydrographic and optical properties in the entire water column, even when highly stratified (Δσt = ∼3.0 kg m−3, decreasing to 0.8 kg m−3 post hurricane), and causes massive resuspension, due initially to wave shear stress that was later dominated by current shear. Restratification progressed rapidly after the hurricane passed. During spring the water column started as a weakly stratified two‐layer system hydrographically and optically but evolved into three layers as stratification developed. Strong spring storms affected both surface and bottom layers but with decreasing impact as the water column stratified.

Contrasting Growth Rate Patterns in Eighteen Tree Species From a Post‐Hurricane Forest in Nicaragua1

ABSTRACTHurricane Joan struck the Caribbean Coast of Nicaragua in October 1988 causing extensive damage to the lowland rain forest of the zone. Six permanent plots were established in 1990 and the growth rates of all individuals in a total area of 6000 m2 monitored for six years. Eighteen of the species were abundant enough to measure species‐specific growth rates. The post hurricane successional process included a great deal of resprouting of pre‐existing individuals and the current state of the forest includes a low but very dense canopy, suggesting that competition is entering an intensive phase. Specific growth rates between the time of the hurricane and the present thus represent establishment or regenerative growth rates and provide an indication of whether or not distinct regeneration niches exist. Three distinct patterns of growth rate seem apparent, fast‐growing heliophyles (eight species), slow‐growing resprouters (nine species), and vochysia ferruginea, which seems to have a special pattern.

Disturbance and neutral competition theory in rain forest dynamics

Subsequent to a disturbance in a tropical rain forest, many new stems arrive, either as new seedlings, previously established seedlings, small saplings, newly germinating seeds that were in the seed bank previously, or as newly germinating seeds that arrived after the disturbance. As the new stems grow, they eventually enter a stage of intense competition, at which point competitive thinning occurs. To describe the various patterns this process may take, a theoretical focus is proposed in which the neutrality of competition among different species of rain forest trees is assumed. Using the total biomass and total number of stems as state variables, the dynamic interaction between these two variables in the post hurricane forest is described. Using this model, six distinct patterns of post disturbance succession are recognized and discussed. Data from post hurricane succession in a tropical rain forest in Nicaragua are applied to one aspect of the theory.

Damage and Responsiveness of Jamaican Montane Tree Species after Disturbance by a Hurricane

A severe hurricane affected Jamaican montane rain forests in 1988. We made local and widespread measurements of tree condition in three periods: prehurricane 1974–1984 (preh.); hurricane 1984—1989 (h.); and post—hurricane 1989—1992 (post—h.). In the h. period, 7.22% of stems and 4.72% of the total basal area died; crown loss was the most frequent cause of mortality. Among individual tree species, the hurricane caused a large range in mortality (0—26%) and non—fatal damage. Post—h. mortality was greater than mortality in the h. period, and varied among species. Post—h. stem growth rates (all species combined) were more than double the prehurricane rates, but species showed a considerable range from no significant increase to eight times greater. We classified 20 common tree species using damage scores (normalized h. mortality, plus normalized change in mortality from preh. to post—h., plus normalized complete crown loss in h.) and response scores (normalized change, preh. to post—h., in recruitment to the ≥ 3 cm dbh size class, plus normalized change in growth rate from preh. to post—h., plus normalized frequency of sprouts). Species were assigned to one of four groups: resistant (11 species), with low damage and low response; susceptible (5 species), with high damage and low response; resilient (1 species), with high damage and high response; and usurpers (3 species), with low damage and high responsiveness. The grouping of species was broadly related to their regeneration requirements. Most species with seedlings usually found under closed canopy were resistant; three of the four species with seedlings usually found on landslides were also resistant. Species with seedlings most frequently found in gaps included resilient, susceptible, and usurper species, but were not usually resistant. It is likely that the three species classified as usurpers will increase their relative abundance in the forest in the next decades and that Cyathea pubescens, which was very susceptible, will decrease in relative abundance of adults. Most of the other species are likely to have small changes in their relative abundances. Thus, at present, hurricanes have few long—term effects on the forests, although a change in the disturbance regime may alter this.