College of Charleston
  • Charleston, United States
Recent publications
This conceptual paper puts forth sources of secondary and primary data that can assist destinations in developed countries track and ultimately improve their communities' tourism performance and resilience across four pillars of tourism sustainability: visitor economy, resident support, workforce satisfaction, and environmental health. Such data sources can be used by community leaders to formulate key performance indicators (KPIs) critical in building resilience. The impetus behind these proposed solutions is based on the assumption that the high cost and complexity of collecting and analyzing data on an ongoing basis have plagued the broad adoption of communities engaging in sustainable initiatives. We contend that given access to suitable data, destinations can be better managed as ecosystems in line with sustainable community objectives.
The goals of this paper are: (1) to bring attention to the existence and utility of multiple optimal rankings for the linear ordering problem, (2) to make the case for finding some or all of these multiple optimal rankings, (3) to provide an efficient algorithm that determines the existence of multiple optimal rankings, (4) to provide algorithms that find a sample of all optimal rankings, and (5) to connect multiple optimal rankings to fairness in ranking. We create algorithms to find the two nearest optimal rankings, the two farthest optimal rankings, and a so-called centroid ranking nearest to the centroid, which summarizes the information in all optimal rankings.
Distribution of Earth’s biomes is structured by the match between climate and plant traits, which in turn shape associated communities and ecosystem processes and services. However, that climate–trait match can be disrupted by historical events, with lasting ecosystem impacts. As Earth’s environment changes faster than at any time in human history, critical questions are whether and how organismal traits and ecosystems can adjust to altered conditions. We quantified the relative importance of current environmental forcing versus evolutionary history in shaping the growth form (stature and biomass) and associated community of eelgrass ( Zostera marina ), a widespread foundation plant of marine ecosystems along Northern Hemisphere coastlines, which experienced major shifts in distribution and genetic composition during the Pleistocene. We found that eelgrass stature and biomass retain a legacy of the Pleistocene colonization of the Atlantic from the ancestral Pacific range and of more recent within-basin bottlenecks and genetic differentiation. This evolutionary legacy in turn influences the biomass of associated algae and invertebrates that fuel coastal food webs, with effects comparable to or stronger than effects of current environmental forcing. Such historical lags in phenotypic acclimatization may constrain ecosystem adjustments to rapid anthropogenic climate change, thus altering predictions about the future functioning of ecosystems.
Purpose Recent studies suggest that 24-h urine osmolality (UOsm) for optimal water intake should be maintained < 500 mmol·kg⁻¹. The purpose of this study was to determine the total water intake (TWI) requirement for healthy adults to maintain optimal hydration as indicated by 24-h urine osmolality < 500 mmol·kg⁻¹. Methods Twenty-four-hour UOsm was assessed in 49 men and 50 women residing in the United States (age: 41 ± 14 y, body mass index: 26.3 ± 5.2 kg·m⁻²). TWI was assessed from 7-day water turnover, using a dilution of deuterium oxide, corrected for metabolic water production. The diagnostic accuracy of TWI to identify UOsm < 500 mmol·kg⁻¹ was evaluated using receiver operating characteristic (ROC) analysis in men and women separately. Results Twenty-four-hour UOsm was 482 ± 229 and 346 ± 182 mmol·kg⁻¹ and TWI was 3.57 ± 1.10 L·d⁻¹ and 3.20 ± 1.27 L·d⁻¹ in men and women, respectively. ROC analysis for TWI detecting 24-h UOsm < 500 mmol·kg⁻¹ in men yielded an area under the curve (AUC) of 77.4% with sensitivity, specificity, and threshold values of 83.3%, 64.5%, and 3.39 L·d⁻¹, respectively. The AUC was 82.4% in women with sensitivity, specificity, and threshold values of 85.7%, 72.1%, and 2.61 L·d⁻¹. Conclusion Considering threshold values in men and women of 3.4 L·d⁻¹ and 2.6 L·d⁻¹, respectively, maintaining TWI in line with National Academy of Medicine guidelines of 3.7 L·d⁻¹ in men and 2.7 L·d⁻¹ in women should be sufficient for most individuals in the United States to maintain 24-h UOsm < 500 mmol·kg⁻¹.
Recollection of family unpredictability in one’s childhood has been associated with depression and/or anxiety (Hood et al., 2019; Ross et al., 2016); however, it is unclear whether low levels of unpredictability are beneficial for our well-being. Following the positive psychology trend, the present study assessed whether less unpredictability (i.e., more predictability) is associated with mental health (life satisfaction, love of life, and happiness) in two samples, and whether these relationships relate to control and personal predictability beliefs. Among college students (N = 161), mental health correlated with more family predictability, weaker unpredictability beliefs, and more internality. In addition, we detected two moderation models in the student sample: stronger personal unpredictability beliefs dampened the relationship between family predictability and life satisfaction, and low internality intensified the relationship between low family predictability and love of life. In a separate study, adults (N = 220) with stronger mental health also reported more family predictability, weaker personal unpredictability beliefs, and internality. Beliefs regarding internality and personal unpredictability mediated the relationship between family unpredictability and both love of life and life satisfaction. Finally, regression analysis indicated a moderation, in that the combination of less family predictability and stronger unpredictability beliefs appears particularly detrimental for adults’ love of life. Taken together, one’s family of origin and current beliefs (that likely develop in the context of that family) relate to current mental health. We conclude with limitations and implications of our findings.
The diet of a potentially omnivorous coastal shark species, the bonnethead (Sphyrna tiburo), was examined in the western Atlantic along the coast of the southeastern United States. A total of 423 stomachs collected from Texas, Alabama, Florida and South Carolina were analyzed using standardized stomach content analysis methods. The diet was dominated by crabs, primarily portunids (Callinectes spp.), across the geographical range analyzed, though the relative importance of crabs varied between regions. Ontogenetic shifts in diet were not observed throughout the region studied. Female and male bonnetheads in South Carolina displayed different diets, particularly in the amount of portunid crabs consumed, with a higher proportion ingested by females. Bonnetheads consumed limited amounts of seagrasses in all regions except in South Carolina, where they occupy habitats without seagrasses in marsh dominated bays and estuaries. This finding indicates that, at least seasonally, seagrasses are not an essential part of the diet of this shark species and may only occur in stomachs as accidental ingestion.
Biological invasions can pose a severe threat to coastal ecosystems, but are difficult to track due to inaccurate species identifications and cryptic diversity. Here, we clarified the cryptic diversity and introduction history of the marine amphipod Ampithoe valida by sequencing a mtDNA locus from 683 individuals and genotyping 10,295 single-nucleotide polymorphisms (SNPs) for 349 individuals from Japan, North America and Argentina. The species complex consists of three cryptic lineages: two native Pacific and one native Atlantic mitochondrial lineage. It is likely that the complex originated in the North Pacific and dispersed to the north Atlantic via a trans-arctic exchange approximately 3 MYA. Non-native A. valida in Argentina have both Atlantic mitochondrial and nuclear genotypes, strongly indicating an introduction from eastern North America. In two eastern Pacific estuaries, San Francisco Bay and Humboldt Bay, California, genetic data indicate human-mediated hybridization of Atlantic and Pacific sources, and possible adaptive introgression of mitochondrial loci, nuclear loci, or both. The San Francisco Bay hybrid population periodically undergoes population outbreaks and profoundly damages eelgrass Zostera marina thalli via direct consumption, and these ecological impacts have not been documented elsewhere. We speculate that novel combinations of Atlantic and Pacific lineages could play a role in A. valida’s unique ecology in San Francisco Bay. Our results reinforce the notion that we can over-estimate the number of non-native invasions when there is cryptic native structure. Moreover, inference of demographic and evolutionary history from mitochondrial loci may be misleading without simultaneous survey of the nuclear genome.
Size-assortative pairing is common across a wide range of taxa. In many cases, both sexes would benefit from pairing with a mate larger than themselves. As males and females cannot simultaneously be larger than their pair mate, size differences within pairs reflect which sex is able to obtain this benefit. Snapping shrimp can be found in pairs year-round, and both males and females would benefit from pairing with larger individuals. Larger females are more fecund; males, then, are likely to benefit from pairing with larger females primarily in the reproductive season. Larger individuals are more successful competitors and females benefit more from shared burrow defense than males; for females, then, benefits of pairing with larger males are likely to accrue year-round. In this study, we use field data to test whether within-pair size differences in snapping shrimp correspond more to male or female interests, and whether this outcome differs between seasons. We find that size-assortative pairing varies seasonally: although body sizes of paired males and females are highly correlated year-round, the within-pair size difference is greater during the reproductive season than the nonreproductive season. Furthermore, within pairs, females are larger than males during the reproductive season, while pairs are size-matched or male-biased during the nonreproductive season. These changes in within-pair size relationships suggest seasonal differences in which sex has greater control over pair formation, and highlight nonreproductive benefits associated with monogamous pairing. In addition, these results underscore the importance of considering temporal variation in studies of size-assortative pairing. Significance statement In many taxa, it is advantageous for both males and females to mate with larger individuals. As both sexes cannot simultaneously mate with larger individuals, size relationships within pairs reflect the outcome of this sexual conflict. In snapping shrimp, pairs cooperate in defending their burrows from invading conspecifics, and larger individuals are better competitors; larger females are also more fecund. Thus, males obtain a reproductive advantage from mating with larger females, while for females, mating with larger males provides social (territorial defense) benefits. Here, we find seasonal differences in within-pair size relationships, such that females are larger than males during the reproductive season, but pairs in the nonreproductive season are size-matched or male-biased. These results suggest seasonal variation in the outcome of conflict over body size within pairs, and highlights the need to consider temporal variation in size-assortative pairing.
Objective: To determine the impact of increased load on the temporomandibular joint (TMJ) from mice deficient in the extracellular matrix protease ADAMTS5. Materials and methods: Wire springs exerting 0.5 N for 1 h/day for 5 days (Adamts5+/+ -n = 18; Adamts5-/- n = 19) or 0.8 N for 1 h/day for 10 days (Adamts5+/+-n = 18; Adamts5-/- n = 17) were used to increase murine TMJ load. Safranin O-staining was used to determine mandibular condylar cartilage (MCC) morphology. Chondrogenic factors Sox9 and aggrecan were immunolocalized. Microcomputed topography was employed to evaluate mineralized tissues, and Tartrate-Resistant Acid Phosphatase staining was used to quantify osteoclasts. Results: Increased load on the mandibular condyle of Adamts5-/- mice resulted in an increase in the hypertrophic zone of mandibular condylar cartilage (MCC) compared to normal load (NL) (P < 0.01). In the trabecular bone of the mandibular condyle, the total volume (TV), bone volume (BV), trabecular thickness (TbTh), and trabecular separation (TbSp) of the mandibular condyles in Adamts5-/- mice (n = 27) did not change significantly with increased load, compared to Adamts5+/+ (n = 38) that exhibited significant responses (TV-P < 0.05; BV-P < 0.001; TbTh-P < 0.01; TbSp-P < 0.01). The bone volume fraction (BV/TV) was significantly reduced in response to increased load in both Adamts5-/- (P < 0.05) and Adamts5+/+ mandibular condyles (P < 0.001) compared to NL. Increased load in Adamts5-/- mandibular condyles also resulted in a dramatic increase in osteoclasts compared to Adamts5-/- NL (P < 0.001) and to Adamts5+/+ with increased load (P < 01). Conclusion: The trabeculated bone of the Adamts5-/- mandibular condyle was significantly less responsive to the increased load compared to Adamts5+/+. ADAMTS5 may be required for mechanotransduction in the trabeculated bone of the mandibular condyle.
We derive the precise stability criterion for smooth solitary waves in the b-family of Camassa–Holm equations. The smooth solitary waves exist on the constant background. In the integrable cases b=2 and b=3, we show analytically that the stability criterion is satisfied and smooth solitary waves are orbitally stable with respect to perturbations in H3(R). In the non-integrable cases, we show numerically and asymptotically that the stability criterion is satisfied for every b>1. The orbital stability theory relies on a Hamiltonian formulation of the b-family which is different from the Hamiltonian formulations available for b=2 and b=3.
B2B technology-enabled services, such as telecommunications, depend on buyers' internal practices to manage resources within their branch facilities. This paper introduces the concept of B2B buyer operational capability (B2B-BOC) as the bundle of facility-level practices (strategic emphasis, employee training, infrastructure management, and security) that, together with supplier information quality, are necessary for continuous technology-enabled service delivery (service continuity). We use survey data from 300 buyers in Brazil to test our hypothesis. Results show that (i) B2B-BOC completely mediates the effect of supplier information quality on service continuity and that (ii) B2B-BOC varies significantly among facilities of the same buyer.
The 2020 year-end holidays were a time of much apprehension regarding COVID-19, with U.S. health officials concerned that travel would result in a post-holiday surge of the disease. As such, much effort was expended encouraging people to forego their normal travel. Many Americans, however, ignored this advice and a strong uptick of travel within the U.S. was soon followed by an alarming increase in COVID cases. A U.S. online survey was conducted to better understand those individuals who made the risky decision to travel despite being encouraged by their government not to do so. Those who traveled for the holidays were compared with those who stayed home, based on their attitudes toward COVID, various psychographic characteristics associated with risk, political attitudes, and demographics. The between-group differences, shared herein, were startlingly clear. The findings are of theoretical value and will prove useful when setting policy and messaging during future crises.
Background: As overdose rates increase, it is critical to better understand the causes and contexts of overdose, particularly for college students who exhibit high rates of alcohol and drug use. The purpose of this study was to examine the social contexts of U.S. college students' overdose experiences (their own, witnessed, and family'/friends'), and to assess the correlates of personal overdose. Methods: A cross-sectional survey containing open- and closed-ended questions about overdose encounters was completed by undergraduate students at a southeastern American university (n = 1,236). Descriptive frequencies assessed prevalence, substance involvement, and fatalities associated with different encounter types. A content analysis of open-ended responses examined the social contexts of encounters. Multivariate logistic regression was used to assess the correlates of personal overdose. Results: Forty-one percent of respondents reported at least one type of overdose encounter and witnessed overdose was most common. Substances involved varied across encounter type and 20-40% of respondents reported overdose-related fatalities. Students who encountered overdose often reported multiple experiences and many attributed overdoses to mixing substances. Respondents commonly encountered overdose as intervening bystanders and overdose events were often perceived to be intentional or the result of using substances to cope with stress/mental health concerns. Personal overdose was significantly associated with having ever mixed alcohol with prescription drugs, been diagnosed with a mental disorder, witnessed an overdose, and had a family member/friend overdose. Conclusion: Findings suggest a need for future research into the contexts and consequences of students' overdose encounters to more effectively tailor overdose prevention/response initiatives within college communities.
The Striatal Beat Frequency (SBF) model of interval timing uses many neural oscillators, presumably located in the frontal cortex (FC), to produce beats at a specific criterion time T c . The coincidence detection produces the beats in the basal ganglia spiny neurons by comparing the current state of the FC neural oscillators against the long-term memory values stored at reinforcement time T c . The neurobiologically realistic SBF model has been previously used for producing precise and scalar timing in the presence of noise. Here we simplified the SBF model to gain insight into the resource allocation problem in interval timing networks. Specifically, we used a noise-free SBF model to explore the lower limits of the number of neural oscillators required for producing accurate timing. Using abstract sine-wave neural oscillators in the SBF-sin model, we found that the lower limit of the number of oscillators needed is proportional to the criterion time T c and the frequency span ( f max − f min ) of the FC neural oscillators. Using biophysically realistic Morris–Lecar model neurons in the SBF-ML model, the lower bound increased by one to two orders of magnitude compared to the SBF-sin model.
Many species, including humans, show both accurate timing − appropriate time estimation in the seconds to minutes range − and scalar timing − time estimation error varies linearly with estimated duration. Behavioral paradigms aimed at investigating interval timing are expected to evaluate these dissociable characteristics of timing. However, when evaluating interval timing in models of neuropsychiatric disease, researchers are confronted with a lack of adequate studies about the parent (background) strains, since accuracy and scalar timing have only been demonstrated for the C57BL/6 strain of mice (Buhusi, Aziz, Winslow, Carter, Swearingen, & Buhusi (2009) Behav. Neurosci., 123 , 1102–1113). We used a peak-interval (PI) procedure with three intervals − a protocol in which other species, including humans, demonstrate accurate, scalar timing − to evaluate timing accuracy and scalar timing in three strains of mice frequently used in genetic and behavioral studies: 129, Swiss-Webster (SW), and C57BL/6. C57BL/6 mice showed accurate, scalar timing, while 129 and SW mice showed departures from accuracy and/or scalar timing. Results suggest that the genetic background/strain of the mouse is a critical variable for studies investigating interval timing in genetically engineered mice. Our study validates the PI procedure with multiple intervals as a proper technique, and the C57BL/6 strain as the most suitable genetic background to date for behavioral investigations of interval timing in genetically engineered mice modeling human disorders. In contrast, studies using mice in 129, SW, or mixed-background strains should be interpreted with caution, and thorough investigations of accuracy and scalar timing should be conducted before a less studied strain of mouse is considered for use in timing studies.
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2,713 members
Sorinel Oprisan
  • Department of Physics and Astronomy
Douglas A. Ferguson
  • Department of Communication
Dean M Connor
  • Department of Physics and Astronomy
Louis E Burnett
  • Department of Biology
Renée Mccauley
  • Department of Computer Science
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