California State University, Channel Islands
  • Camarillo, California, United States
Recent publications
Surfing has increased in cultural, social, and economic importance through the last century and is now globally significant. Predicated on the natural phenomenon of ocean waves interacting with coasts, surfing’s future is threatened by Earth’s changing climate. This paper provides a comprehensive review of physical processes, including swell generation, wave breaking, and coastal dynamics, relevant for the locations — surf breaks — where surfing occurs and the myriad mechanisms through which each can be affected by a changing climate. We propose an organizing framework for these impacts characterizing them based on their mode of action as direct versus indirect, as well as by their magnitude, and conclude that some impacts (such as sea level rise) may threaten some breaks but on more protracted timelines, whereas other impacts (such as coastal armoring implemented in response to climate change) may pose more immediate, existential threats. This framework underscores the importance of local environmental knowledge of a given surf break for understanding its susceptibility to climate change and informs a Surf Break Vulnerability–Climate Change Assessment Tool (SurfCAT), designed to enable improved wave stewardship by local resource managers and stakeholders in the face of a changing climate.
Supplemental Materials provided by authors for article "The impacts of climate change on surfing resources"
Introduction: To develop an in-house acrylic-based step-wedge phantom with several thickness configurations for calibrating computed tomography (CT) localizer radiographs in order to measure the water-equivalent diameter (D w ) and the size-specific dose estimate (SSDE). Method: We developed an in-house step-wedge phantom using 3 mm thick acrylic, filled with water. The phantom had five steps with thicknesses of 6, 12, 18, 24, and 30 cm. The phantom was scanned using a 64-slice Siemens Definition AS CT scanner with tube currents of 50, 100, 150, 200, and 250 mA. The relationship between pixel value (PV) and water-equivalent thickness (t w ) was obtained for the different step thicknesses. This was used to calibrate the CT localizer radiographs in order to measure D w and SSDE. The results of D w and SSDE from the radiographs were compared with those calculated from axial CT images. Results: The relationship between PV and t w from CT localizer radiographs of the phantom step-wedge produced a linear relationship with R ² > 0.990. The linear relationships of the D w and SSDE values obtained from CT localizer radiographs and axial CT images had R ² values > 0.94 with a statistical test of p -value > 0.05. The D w difference between those from CT localizer radiographs and axial CT images was 3.7% and the SSDE difference between both was 4.3%. Conclusion: We have successfully developed a step-wedge phantom to calibrate the relationship between PV and t w . Our phantom can be easily used to calibrate CT localizer radiographs in order to measure D w and SSDE.
Radiation of thoracic computed tomography (CT) involves the breast although it is not considered an organ of interest. According to the International Commission on Radiological Protection (ICRP) No. 103, the breast is an organ with a high level of sensitivity when interacting with x-rays, increasing the potential risk of breast cancer. Therefore, the radiation dose must be optimized while maintaining image quality. The dose optimization can be accomplished using a radiation shield. This study aims to determine the effect of silicone rubber(SR)-lead (Pb)in various thicknesses as an alternative protective material limiting dose and preserving the image quality of the breast in thoracic CT. SR-Pb was made from SR and Pb by a simple method. The SR-Pb had thicknesses of 3, 6, 9, and 12 mm. The breast dose was measured using a CT dose profiler on the surface of the breast phantom. The CT number and the noise level of the resulting image were determined quantitatively. The dose without the radiation shield was 5.4 mGy. The doses measured using shielding with thicknesses of 3, 6, 9, and 12 mm were 5.2, 4.5, 4.3, and 3.3 mGy, respectively. Radiation shielding with a thickness of 12 mm reduced breast surface dose by up to 38%. The CT numbers and noise levels for the left and right breast phantom images were almost the same as those without radiation shields indicating there were only slight artifacts in the image. Therefore, SR-Pb is considered a good shielding material which can be applied in a clinical setting by placing it directly on the breast surface for dose optimization.
Chemoresistance and plasticity of tumor-initiating stem-like cells (TICs) promote tumor recurrence and metastasis. The gut-originating endotoxin-TLR4-NANOG oncogenic axis is responsible for the genesis of TICs. This study investigated mechanisms as to how TICs arise through transcriptional, epigenetic, and post-transcriptional activation of oncogenic TLR4 pathways. Here, we expressed constitutively active TLR4 (caTLR4) in mice carrying pLAP-tTA or pAlb-tTA, under a tetracycline withdrawal-inducible system. Liver progenitor cell induction accelerated liver tumor development in caTLR4-expressing mice. Lentiviral shRNA library screening identified histone H3K4 methylase SETD7 as central to activation of TLR4. SETD7 combined with hypoxia induced TLR4 through HIF2 and NOTCH. LIN28 post-transcriptionally stabilized TLR4 mRNA via de-repression of let-7 microRNA. These results supported a LIN28-TLR4 pathway for the development of HCCs in a hypoxic microenvironment. These findings not only advance our understanding of molecular mechanisms responsible for TIC generation in HCC, but also represent new therapeutic targets for the treatment of HCC.
We investigated the accuracy of automatic measurements of the effective diameter (Deff) using IndoseCT software with axial computed tomography (CT) images of polyester-resin (PESR) phantoms of various diameters. The phantoms used PESR as the base material mixed with Methyl Ethyl Ketone Peroxide (MEKP) as the catalyst. The phantom diameters were 8, 16, 24, and 32 cm. The phantoms were scanned with a CT scanner from edge-to-edge position with field of views (FOVs) of 30, 35, 40, 45, and 50 cm. The Deff was measured from all slices along the z-axis. It was found that the automatic Deff measurements were very accurate. The Deff values were different by less than 0.02 cm for all diameters and all FOVs used. The maximum difference was obtained a ta diameter of 16 cm and FOV of 35 cm. We found that the precision of Deff measurements along the z-axis was very good with a maximum standard deviation of 0.01 cm. The relationships between phantom diameter and measured Deff for all FOVs had p-values < 0.001 and r 2 = 1.000. Therefore, the IndoseCT is able to accurately and precisely measure Deff to facilitate estimating the patient dose in the SSDE metric.
The aim of this study is to measure the volumetric computed tomography dose index (CTDIvol) for different tube voltages for a polyester-resin (PESR) phantom, and to compare it to values for a standard polymethyl methacrylate (PMMA) phantom. Both phantoms are head phantoms with a diameter of 16 cm. The phantoms were scanned by a CT scanner (GE Revolution EVO 64/128 slice) with tube voltages of 80, 100, 120, and 140 kV. The other scan parameters were constant (i.e. tube current of 100 mA, rotation time of 1 s, and collimation width of 10 mm). The CTDI100,c and CTDI100,p were obtained by measuring the dose with an ionization chamber inserted into five holes within the phantoms. The CTDIvol was calculated based on the CTDI100,c and CTDI100,p values. The measurements were repeated three times for each hole. It was found that the CTDIvol values for the PESR phantom were dependent on tube voltage value, and were similar to the dependency in a PMMA phantom. The maximum CTDIvol difference between the PESR and PMMA phantoms was 7.5%. We conclude that the dose measured in the PESR phantom is similar to that in the PMMA phantom and that the PESR phantom can be used as an alternative if the PMMA phantom is not available.
Dauphin Island, Alabama is a particularly egregious example of moral hazard and maldevelopment and the policies and practices that allow this to take place. The west end of Dauphin Island offers a clear case study of such practices and illustrates the crucial role that State and local regulation play in curtailing many of the moral hazard effects of federal disaster relief funding in promoting maldevelopment. Where unrestricted, moral hazard can act as an incentive to build or rebuild in at-risk areas, and unlike many other coastal areas, Dauphin Island lacks policies and requirements which restrict such development. Using the richest dataset available for the island and geospatial visualization, this analysis presents Dauphin Island as a case study of the potential consequences of unrestricted, heavily subsidized maldevelopment, and outlines the policies that enabled it to take place. Dauphin Island demonstrates that Federal disaster relief programs other than the National Flood Insurance Program (NFIP) can contribute to maldevelopment. On Dauphin Island, Federal disaster relief from a combination of programs created a continual cycle of rebuilding on the island since 1979. Crucially, local coastal management policy acts as a valve restricting and directing the flow of federal funds. On Dauphin Island, those funds have not been directed towards resiliency, but towards maintaining and rebuilding the most vulnerable portion of the island. Geospatial visualization of current parcel development patterns clearly shows the consequences of these incentives to build and rebuild in areas that are known to be risky in terms of future storms and flooding. In particular, this analysis indicates that the “typical” property on the island is: (1) not owned by island residents, and (2) is a second home either rented out or used seasonally. Thus, a significant portion of the State, Local, and Federal expenditures designed for local disaster relief benefit property owned by off-island and out-of-state residents used for second homes. These high-value, high-risk properties result in the island receiving disproportionately high (FEMA) expenditures.
The PROBIES diagnostic is a new, highly flexible, imaging and energy spectrometer designed for laser-accelerated protons. The diagnostic can detect low-mode spatial variations in the proton beam profile while resolving multiple energies on a single detector or more. When a radiochromic film stack is employed for “single-shot mode,” the energy resolution of the stack can be greatly increased while reducing the need for large numbers of films; for example, a recently deployed version allowed for 180 unique energy measurements spanning ∼3 to 75 MeV with <0.4 MeV resolution using just 20 films vs 180 for a comparable traditional film and filter stack. When utilized with a scintillator, the diagnostic can be run in high-rep-rate (>Hz rate) mode to recover nine proton energy bins. We also demonstrate a deep learning-based method to analyze data from synthetic PROBIES images with greater than 95% accuracy on sub-millisecond timescales and retrained with experimental data to analyze real-world images on sub-millisecond time-scales with comparable accuracy.
While cannabis legalization in the United States has become more commonplace, differences in attitudes toward its use persist. Negative attitudes toward cannabis create barriers to care for those seeking its use for therapeutic purposes. Existing research regarding the attitudes surrounding cannabis is specific to medical cannabis (MC) use or cannabis use in general. To address this gap, the present research sought to explore the demographic factors that influence attitudes toward recreational cannabis, including gender, age, ethnicity, race, level of education, marital status, number of children, the legal status of cannabis in the state of residency, employment status, political party affiliation, political view, and religion. The Recreational Cannabis Attitudes Scale (RCAS) was used to measure participants' attitudes toward recreational cannabis. A one-way analysis of variance (ANOVA) or one-way Welch ANOVA was used to determine variations in RCAS scores between different demographic groups. Data from 645 participants indicated that gender (P = 0.039), employment status (P = 0.016), political party affiliation (P = 0.002), political view (P = 0.0005), the legal status of the state of residence (P = 0.003), religion (P = 0.0005), and experience with cannabis (P = 0.0005) had significant variations between groups regarding attitudes toward recreational cannabis. Understanding the factors that inform attitudes is critical to efforts to destigmatize cannabis use. Education about cannabis is an effective measure in reducing stigma, and paired with demographic information, advocacy efforts can be more accurately targeted.
Lorena V. Márquez’s La Gente: Struggles for Empowerment and Community Self-Determination in Sacramento is a solid, well-researched book that introduces readers to grassroots activists they have not heard or read about, but whose experiences illuminate the rich diversity and complexity of the Chicana/o Movement. It’s a refreshing intervention to the historiography of the Chicana/o Movement that remains wedded to charismatic male leaders, well-known organizations, and big events. These everyday folks, or la gente, who resided in Sacramento’s barrios, attended public schools and colleges, and labored in the canneries, were just as pivotal to the Chicana/o Movement. Like David Montejano’s Quixote’s Soldiers: A Local History of the Chicano Movement, 1966–1981 (2010), Márquez examines a broad range of participants in the Chicana/o Movement; however, La Gente focuses on the greater Sacramento Valley that includes urban and rural communities. By adopting a translocal and regional approach, Márquez uncovers new sites of struggle that have received little attention by scholars.
This article presents results from an experimental study of workers tasked with evaluating professionals with identical workplace performances who differed with respect to hours worked and gender, isolating two mechanisms through which overwork leads to workplace inequality. Evaluators allocated greater organizational rewards to overworkers and perceived overworkers more favorably compared to full-time workers who performed similarly in less time, a practice that disproportionately rewards men over equivalently performing, more efficient women. Additionally, the magnitude of the overwork premium is greater for men than for women. We then use path analyses to explore the processes by which evaluators make assumptions about worker characteristics. We find overwork leads to greater organizational rewards primarily because employees who overwork are perceived as more committed—and, to a lesser extent, more competent—than full-time workers, although women’s overwork does not signal commitment or competence to the same extent as men’s overwork.
We developed a software to automatically measure the linearity between the CT numbers and densities of objects using an ACR 464 CT phantom, and investigated the CT number linearity of 16 different CT scanners. The software included a segmentation-rotation method. After segmenting five objects within the phantom image, the software computed the mean CT number of each object and plotted a graph between the CT numbers and densities of the objects. Linear regression and coefficients of regression, R 2 , were automatically calculated. The software was used to investigate the CT number linearity of 16 CT scanners from Toshiba, Siemens, Hitachi, and GE installed at 16 hospitals in Indonesia. The linearity of the CT number obtained on most of the scanners showed a strong linear correlation (R 2 > 0.99) between the CT numbers and densities of the five phantom materials. Two scanners (Siemens Emotion 16) had the strongest linear correlation with R 2 = 0.999, and two Hitachi Eclos scanners had the weakest linear correlation with R 2 < 0.99.
Purpose: This study aims to develop a software tool for investigating patient centering profiles of axial CT images and to implement it to evaluate practices in three hospitals in Indonesia. Methods: The evaluation of patient centering accuracy was conducted by comparing the center coordinate of the patient’s image to the center coordinates of the axial CT image. This process was iterated for all slices to yield an average patient mis-centering in both the x- and y-axis. We implemented the software to evaluate the profile of centering on 268 patient images from the head, thorax, and abdomen examinations taken from three hospitals. Results: We found that 82% of patients were mis-centered in the y-axis (i.e., placed more than 5 mm from the iso-center), with 49% of patients placed 10–35 mm from the iso-center. Most of the patients had a tendency to be placed below the iso-centers. In head examinations, patients were more precisely positioned than in the other examinations. We did not find any significant difference in mis-centering between males and females. We found that there was a slight difference between mis-centering in adult and pediatric patients. Conclusion: Software for automated patient centering was successfully developed. Patients in three hospitals in Indonesia had a tendency to be placed under the iso-center of the gantry.
Public programs have been charged with implementation of evidence-based practices (EBPs) to improve outcomes for children with autism. However, research indicates that scale-up of EBPs poses challenges. This study identifies perceived variables linked to effective statewide scale-up of EBPs in special education by exploring implementation climate and leadership across special education organization types (e.g., schools, districts, and regional consortiums). A simultaneous QUAL + QUAN mixed methods design was employed with the primary function of convergence and triangulation. Data included focus groups with 30 special educators and a statewide survey completed by 656 school personnel. In general, perceptions of implementation climate and leadership are weak in special education organizations with strengths at regional levels focused on special education and increased challenges at the school and district levels. Implications for practice and future research are identified.
The marine intertidal mussel Mytilus californianus aggregates to form beds along the Pacific shores of North America. As a sessile organism it must cope with fluctuations in temperature during aerial exposure during low-tide events, which elevates maintenance costs and negatively affects their overall energy budget. The function of their digestive gland is to release enzymes that break apart ingested polymers for subsequent nutrient absorption. The effects of elevated aerial warming acclimation on the functioning of digestive gland enzymes are not well studied. In this study we asked whether digestive gland carbohydases and proteases could be overstimulated in warm condition to mitigate the costs related to the heat-shock response. We compared mussels acclimated to a + 9 °C heat-shock during daily low-tide aerial exposure to mussels acclimated to isothermal tidal conditions in a simulated intertidal system. The results showed fairly consistent activities of cellulase, trypsin, and amino-peptidase across tidal variation and between thermal treatments; however, amylase activity was lower in warmed versus cool mussels across low and high-tide. We also observed the expression of heat-shock genes in gill tissue during warm tidal conditions, suggestive that moderate temperatures during aerial exposure can induce a stress response.
Universities have embraced the use of social media around the world. Higher education has incorporated social media and its’ use as an online platform that supports formal and informal communication. Education has embraced the use of social media globally. Social media in higher education is used by universities to communicate with, students, as a support or main “platform” for teaching and learning or as a way of sharing information from university academic based center. This entry on the use of social media in teaching and learning and the associated benefits and challenges.
Institution pages aggregate content on ResearchGate related to an institution. The members listed on this page have self-identified as being affiliated with this institution. Publications listed on this page were identified by our algorithms as relating to this institution. This page was not created or approved by the institution. If you represent an institution and have questions about these pages or wish to report inaccurate content, you can contact us here.
1,488 members
Sonsoles de Lacalle
  • Health Science
Sean Q Kelly
  • Department of Political Science
Houman Dallali
  • Department of Computer Science
Tiina Itkonen
  • School of Education, Dept. of Political Science
Kiki Patsch
  • Department of Environmental Science and Resource Management
One University Drive, 93012, Camarillo, California, United States