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What are Special Collections?
Special collections refer to unique materials that provide both primary and secondary sources to people conducting original research. Our collections are special due to their scarcity or rarity, historical value, monetary value, or research value. Archives are collections of original records created throughout the lifespan of a person, family, organization, or business. These materials essentially provide evidence of the activities, events, functions, and/or responsibilities of the creator(s). Archives and special collections differ from libraries in the types of materials collected and the ways in which they are acquired, organized, described, and made publicly accessible. These differences prompt us to create specific policies and procedures to ensure that our collections can continue to be used for decades or even centuries to come. Special collections refer to unique materials that provide both primary and secondary sources to people conducting original research. Our collections are special due to their scarcity or rarity, historical value, monetary value, or research value. Archives are collections of original records created throughout the lifespan of a person, family, organization, or business. These materials essentially provide evidence of the activities, events, functions, and/or responsibilities of the creator(s). Archives and special collections differ from libraries in the types of materials collected and the ways in which they are acquired, organized, described, and made publicly accessible. These differences prompt us to create specific policies and procedures to ensure that our collections can continue to be used for decades or even centuries to come. Answered by: Kelly Larson

Database Listing

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Discovery

2065163
Optimal harvest strategies with catch-dependent pricing for chub mackerel in South Korea
Chub mackerel (Scomber japonicus) is a key commercial species in South Korea. However, the catch volume of chub mackerel has experienced significant fluctuations over the past few decades, with current trends indicating a decline. Despite regulatory measures such as closed seasons, resource depletion remains a concern, thereby highlighting the requirement for effective management strategies. Numerous previous studies have proposed optimal harvest strategies by assuming constant prices. However, as large catches of mackerel tend to have lower prices, it is crucial to develop optimal harvest strategies that account for this decrease. Thus, we aim to develop a monthly optimal harvest strategy for chub mackerel that considers catch-dependent pricing. We define logarithmic, rational, and irrational catch-dependent price functions and their corresponding objective functions. In addition, we develop an optimal control system based on a discrete age-structured model. We use Pontryagin’s maximum principle to prove the necessary conditions for the optimal harvest strategy under the three catch-dependent pricing functions and perform simulations using the forward–backward sweep method. We compare the optimal harvest strategies under the three catch-dependent pricing scenarios with those under a constant price. The optimal harvest strategies with the rational and irrational price functions are similar to those with a constant price, where the fishing effort increases immediately after spawning and then gradually decreases. In contrast, the optimal harvest strategy with the logarithmic price function involves a gradual increase in fishing effort from July immediately after the spawning period, with the maximum effort in June before the next spawning season. In addition, we compare the effects of monthly closed seasons across the four pricing scenarios. A closed season in July immediately after spawning provides the highest resource recovery efficiency. In contrast, a closed season in June provides the highest catch and profit efficiencies. As the cost per unit of effort increases, the fishing effort, catch, and profit decrease, while the biomass increases, and the profit decrease is smallest under the logarithmic price function. Our method can improve monthly optimal harvest strategies for other species using catch-dependent pricing functions as well as significantly contribute to enhancing fishers’ profit.
Effectiveness of catch-up vaccination from 2009 to 2011 on incidence of hepatitis B in Guangzhou, China: a time series analysis
Background: The high prevalence of hepatitis B weighs heavily on public health in China. In 2009, a catch-up vaccination program for children aged 8–15y was implemented to curb hepatitis B, while the effectiveness of this intervention has not been investigated. We aimed to evaluate the effectiveness of catch-up vaccination on the incidence of hepatitis B in Guangzhou, China.Methods: We obtained individual data of all hepatitis B cases from 2005 to 2019 in Guangzhou from Guangzhou Center for Diseases Control and Prevention. Based on daily reported number of cases, we constructed generalized linear models to estimate the effectiveness of the intervention on the incidence of hepatitis B in each age group from 11 to 25 years. We further estimated the age-standardized effectiveness. Finally, we examined the effectiveness in different subgroups by sex and clinical types of hepatitis B.Results: A total of 58,204 hepatitis B cases among individuals aged 11–25y were reported in Guangzhou from 2005 to 2019, with an average annual age-standardized incidence of 117.30 cases per 100,000 individuals. The catch-up vaccination contributed to an age-standardized 20.02% (95% confidence interval: 15.97%, 23.87%) decrease in the hepatitis B incidence among individuals aged 11–25y and prevented an annual age-standardized average of 17.40 (95% empirical confidence interval [eCI]: 9.24, 23.78) cases per 100,000 individuals from hepatitis B during the study period. The intervention could better protect males (excess incidence rate [EIR]: -21.82 [95% eCI: -30.51, -10.15] cases per 100,000 individuals), and prevent chronic cases (EIR: -24.27 [95% eCI: -30.62, -16.09] cases per 100,000 individuals).Conclusions: The massive catch-up vaccination against hepatitis B among children plays an important role in alleviating the burden of hepatitis B.
Catch crops promote soil physical recovery after forage crop grazing
Soil compaction-induced physical degradation is a threat to sustainable crop production and environmental performance. While measures have been evaluated to alleviate compaction, the impact of catch crops establishment on soil physical recovery following winter grazing remains underexplored. Six New Zealand trials over different years investigated: (1) the effects of soil compaction induced by winter forage crop grazing on soil health, and (2) the effectiveness of catch crops establishment in facilitating soil recovery. Our findings revealed that winter grazing resulted in significant soil physical degradation in the top 10 cm, evidenced by significant reduction in total porosity, macroporosity, available water content, saturated hydraulic conductivity (Ks), and soil quality S index. The degree of soil degradation was higher under increased grazing intensity (fodder beet grazing compared with kale grazing) and wetter conditions. For example, in Te Pirita-2019 with kale, changes in Ks were not significant. However, in Te Pirita-2019 with fodder beet, Ks decreased significantly from 1548 mm day⁻¹ to 88 mm day⁻¹, representing a 94.3 % reduction. Compared with fallow after grazing, growing catch crops promoted soil restoration. Conventional moldboard ploughing and the recently introduced single-pass ‘spader-drill’ outperformed direct drill for soil recovery. This study highlighted the importance of catch crop establishment using conventional tillage and spade drill to mitigate soil degradation resulting from winter forage crop grazing. The spader-drill, where soil conditions allow, is preferred because it allows earlier sowing of catch crops, leading to broader benefits such as increased crop biomass and reduced nitrogen leaching.