Barrier Breakers Research Articles

Building capacity for inclusive informal STEM learning opportunities for autistic learners

BackgroundResearch is needed to better understand the specific challenges for autistic learners in informal STEM learning settings. This study aimed to increase inclusion in STEM museums, with a larger goal of increasing the impact (i.e., learning and application of knowledge during and after visits) of informal STEM learning settings for autistic youth. We conducted an online parent attitudes survey with 93 parents of autistic adolescents and 53 parents of adolescents in the general population to better understand the experiences of autistic adolescents when visiting STEM-related museums. Parent responses informed professional development training for museum staff at four partner museums, which taught strategies to better support autistic learners. Then, autistic adolescents (n = 20) and their parents were randomly assigned to visit one partner and one control museum. They were asked to report their experiences through an online survey and semi-structured interviews.ResultsParticipants who completed the parent attitudes survey indicated significantly lower inclusion, engagement, and general impact of STEM museum visits among autistic adolescents compared to the general population comparison group. Parents of adolescents who visited partner and control museums reported higher STEM impact during visits to partner museums; however, parent-reported inclusion, engagement, and general impact did not differ significantly between partner and control museums. Qualitative analysis identified four themes (Spectrum of Museum Impact; Adolescent-Environment Fit; Barriers to Engagement, and Barrier Breakers), providing context for quantitative findings.ConclusionsFindings underscore the need for increased inclusion for autistic individuals in informal STEM learning environments like museums. This project demonstrated feasibility of professional development training of forward-facing staff and identified several themes that should inform future efforts to improve inclusion in informal STEM learning settings.

The Black Athlete as Hero: American Barrier Breakers From Nine Sports

The Black Athlete as Hero: American Barrier Breakers From Nine Sports

Dahlquist's barriers and much beyond

On the occasion of 60 years to a seminal paper by the Swedish mathematician Germund Dahlquist, this review paper starts by discussing the celebrated Dahlquist's barriers, which are theoretical limitations on the accuracy and stability properties of a broad and important class of time-stepping methods, i.e., Linear Multistep (LMS) methods, for the solution of initial value problems. Perhaps the two most dramatic Dahlquist barriers are the one that precludes an explicit LMS method from being unconditionally stable, and the one that precludes a high-order LMS method from being unconditionally stable. We discuss Dahlquist's barriers and also later barriers proved by other authors. We then discuss some time-stepping methods which seemingly break at least one of Dahlquist's barriers. Of course, the explanation of this “paradox” is that these are not LMS methods, so the barriers do not necessarily apply to them. We relate to two types of barrier breakers: those that break stability barriers (explicit unconditionally-stable methods), and those that break order barriers (high-order explicit or unconditionally-stable methods). We also review some current advanced time-integration techniques which significantly deviate from the LMS format.

Towards a culturally relevant sport pedagogy: lessons learned from African Australian refugee-background coaches in grassroots football

ABSTRACT There is a body of research that indicates the need for community-driven and culturally responsive pedagogies in sport-based interventions. There is much to learn from the pedagogical approaches and experiences of African Australian refugee-background coaches who work with refugee-background young people toward acceptance and affirmation of their cultural and racial identities. This paper explores African Australian refugee-background coaches’ pedagogies in working with African Australian refugee-background young people in a grassroots football programme in Melbourne. Participants included an African Australian refugee-background young woman and four coaches. Data collection spanned a six-month period and included observations and semi-structured interviews. The findings were analysed using Ladson-Billings’ [Ladson-Billings, G. (1995b). Toward a theory of culturally relevant pedagogy. American Educational Research Journal, 32(3), 465–491. https://doi.org/10.3102/00028312032003465; Ladson-Billings, G. (2009). The dreamkeepers : Successful teachers of African American children. Jossey-Bass Publishers; Ladson-Billings, G. (2014). Culturally relevant pedagogy 2.0: A.k.a. The Remix. Harvard Educational Review, 84(1), 74–84. https://doi.org/10.17763/haer.84.1.p2rj131485484751] conceptualisation of Culturally Relevant Pedagogy. The study identified three main themes. First, the coaches considered themselves ‘barrier breakers’: they were able to connect the African Australian refugee-background young people to different resources in and outside of sports contexts to develop their success in football and in life. Second, the coaches considered the sport programme ‘a family’ where they were willing to nurture and support cultural competence by sharing power with the participants and their community. Third, the coaches created spaces for young people to develop awareness that allowed them to critique some of the social inequities experienced. Future studies should continue to move beyond a focus on predominantly white and middle-class providers and coaches in sport-based interventions. By including and foregrounding the voices of coaches who have diverse experiences, more diverse cultural knowledges are validated, enabling the translation of this knowledge into more culturally responsive sport programmes.

Introduction – Female barrier breakers in Pacific region conservation

Introduction – Female barrier breakers in Pacific region conservation

Conservatism in an Innovative Field

The study intention is to understand the nature of digital publishing for children in Sweden and showed, among other things, that digital publishing to a large extent is reproductions of print books. The paper argues that results of the case study can be explained by long-time structures in publishing of print books for children but also that there are barrier breakers. In order to map digital book publishing for children data was gathered from a number of sources and covered digital children’s books published in Swedish 2015–2018. The preliminary results of the study points towards severe gaps in the statistics of children’s digital books and digital publishing in general. Despite the lack of exact statistics observations can be made on the nature of the digital children’s book market in terms of publishing formats, development, publishers and distribution. The results of this study showed a print-based publishing structure of digital books. I argue that this contradiction can be explained by five factors: publishing as a business, copyright, production, authors and audience. These five are linked but provide different perspectives and explanations.

Bile Acids as Modulators of Gut Microbiota Linking Dietary Habits and Inflammatory Bowel Disease: A Potentially Dangerous Liaison

Bile Acids as Modulators of Gut Microbiota Linking Dietary Habits and Inflammatory Bowel Disease: A Potentially Dangerous Liaison

Professional Transitions in the Academy: A Conversation

Journeys are funny things—they do not always take you were you were expecting them to, or even where you want to go. But if you are open to the experience, and committed to reflection, there are interesting lessons to be learned. What does it mean to shift from a practising professional (a lawyer–a social worker) to a discipline-based academic? Or to move beyond a narrow discipline to become a scholar of teaching and learning? What dangers lurk in the swamp of managerialism? How can we escape from the towers of solitude and isolation that characterise debates around academic identity and become true barrier breakers and boundary blenders? The key, for these two travellers, lies in recognising the transformative potential of epistemological fusion.

Language deficit in English and lack of creative education as impediments to Nigeria's breakthrough into the knowledge era

This essay discusses the linguistic and cultural factor that has acted as impediments to Nigeria’s breakthrough into the knowledge era. It identifies language deficit in English by most Nigerians, under- developed state of most Nigerian languages, absence of creative education and the presence of certain cultural taboos which stifles the flourishing of creative thinking as barriers to sustainable development in Nigeria. The essay observes that a paradigm shift from the present rote system of education, transparency in government, drawing up a road map for cultural change as barrier breakers to Nigeria’s inability to break through into the knowledge era. Key words: Language deficit, knowledge era, sustainable development, creativity and innovation skills, modern, knowledge, economy.

Acute Effect of Gamma Irradiation on Gastric Acid Secretion and Gastric Mucosal Integrity in the Rat

The effect of 3- or 6-Gray (Gy) whole-body gamma irradiation on basal and stimulated gastric acid secretion was studied in pylorus-ligated rats. Different groups of rats were irradiated with a single 3- or 6-Gy fraction and examined 7 days after irradiation. Exposure to 3-Gy fraction led to marked increase in basal (nonstimulated) gastric acid output in the 4-h pylorus-ligated rat (47.5% compared with unirradiated controls). After exposure to 6 Gy, only 18.2% increase in gastric acid output was noted compared with unirradiated controls. Under pentagastrin or histamine stimulation, gastric acid secretion in those irradiated with 3- or 6-Gy fraction was markedly reduced compared to that of unirradiated controls. Exposure to 3- or 6-Gy gamma irradiation intensified the degree of gastric mucosal injury evoked by indomethacin or 50% ethanol in a dose-dependent manner. It is concluded that in the pylorus-ligated rat model, lower doses of gamma irradiation increase basal gastric acid secretion and impair the gastric mucosal barrier with marked increase in its permeability to H+ following stimulation of acid secretion or exposure to barrier breakers. Exposure to irradiation is likely to result in failure of the parietal cell to respond to direct stimulation with histamine or pentagastrin.

African American golfers during the Jim Crow era

Preface Introduction Sports and Discrimination The Development of Black Golf From Caddie to Professional: The Making of a Black Golf Pro Golf and the Black Elite The Organization of Black Golf: The United Golfers Association (UGA) Joe Louis: Black Golf Ambassador The Nature of Black Golf Jim Crow Era Golfers in the Black Press Jim Crow Era Golfers Speak in Their Own Words Desegregation Battles The Push to Desegregate Public Golf Courses Barrier Breakers and White Resistance Conclusions Black Golf and White Racism Bibliography Index

A new technique for continuous measurement and recording of gastric potential difference in the rat: Evaluation of NSAID-induced gastric mucosal damage

Disruption of the gastric mucosal barrier by the so-called “barrier breakers” such as ethanol, aspirin, and bile is associated with an increase in gastric potential difference (GPD), that is, a decrease in its negativity. Because a good correlation between the degree of histological damage and changes in GPD has been observed, this parameter has been used increasingly as an index of mucosal integrity. However, the current methodology for measuring GPD is laborious due to the preparation and checking of KCl-agarose bridges prior to each experiment, and calculations—usually handmade—are time-consuming and inaccurate. In this paper, a new method allowing simultaneous measurement and recording of GPD in the rat is described. The method allows a simultaneous recording of intragastric pH and an automatic data analysis. The new technique has been validated by studying mucosal damage induced by aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) (namely indomethacin and droxicam) as well as the mucosal protective activity of an antacid and sucralfate. The similarity between the results obtained in this rat model and those derived from human experiments clearly show that the developed methodology yields results that are predictive for human pharmacology.

Overcoming Barriers to Successful Constructability Implementation Efforts

A barrier to constructability is any significant inhibitor that prevents effective implementation of the constructability program. Barriers to successful implementation of constructability programs are present in almost all organizations at both corporate and project levels. Treatment of constructability barriers should involve a three-phase cycle: identification, mitigation, and review. Initial efforts should focus on determining the presence and relative significance of constructability barriers. Recognition of barriers to constructability has been identified as one of 15 significant parameters critical for effective constructability implementation. Once barriers to constructability are identified within an organization or a project team, they may be mitigated or overcome with certain tactics, known as “barrier breakers.” Such breakers should be both effective in combating the barriers and should be implementable or relatively easy to apply. This paper describes the development, evaluation, characterization, and application of barrier breakers for the seven most prevalent barriers to successful implementation of constructability efforts.

Mucosal secretion and cytoprotection of the rat gastric mucosa.

We carried out a series of experiments to test the hypothesis that many examples of gastric cytoprotection result from the ability of protective agents to elevate mucosal secretion. Specifically, such protection would be effective against barrier breakers that act directly on the mucosal surface. We have previously observed that the protection found to result, in our rat gastric chamber model, from luminal stasis or from sucralfate, was accompanied by increases in the thickness of a juxtamucosal pH gradient. The pH gradient was measured with antimony microelectrodes and was about 900 microns thick over chambered gastric mucosae that had not had the luminal solution stirred for at least 5 min. When the solution was stirred (200 rpm) for 10 min with a plastic paddle, the thickness of the pH gradient was decreased to about 400 microns but recovered to more than 90% of the starting value within 5 min. The thickness of the pH gradient varied from site to site, with a range from about 500 microns to 1,800 microns. However, the thickness was constant at a given site when it was remeasured after about 1 h. Capsaicin at a concentration of 640 microM rapidly increased both gastric blood flow and the thickness of the juxtamucosal pH gradient by about 50%. However, 25 min after removal of the capsaicin the gastric blood flow approached pre-capsaicin levels, and the thickness of the gradient remained increased by nearly 50%. In a third set of experiments, the vulnerability of specific sites on the chambered mucosae to acidified sodium taurocholate was correlated with the thickness of the juxtamucosal pH gradient before exposure to taurocholate.(ABSTRACT TRUNCATED AT 250 WORDS)

Rapid repair of the surface epithelium in human gastric mucosa after acute superficial injury.

Morphologic changes associated with rapid epithelial repair in human gastric mucosa were examined by light and transmission electron microscopy in samples obtained at biopsy. A timed series of samples covering six intervals (3-30 min) after exposure to 50% (vol/vol) ethanol was available. Samples exposed to 25% ethanol and to acidified sodium taurocholate were also studied. Changes indicative of epithelial repair were first seen in samples fixed 15 min after ethanol. In samples fixed 30 and 45 min after exposure to barrier breakers, there were widespread changes indicative of epithelial repair. We have tentatively identified three morphologically distinct types of repair: lateral movement of the epithelial cell basal plasma membrane, which maintains close contact with the basal lamina and which may occur only in the presence of continued vascular perfusion; migration of shortened, cuboidal cells with blunt pseudopods and lamellipodia. This morphology predominated over sites of vascular congestion; and the formation of epithelial arches in which the epithelial cells did not make contact with the underlying basal lamina. Rapid repair by cell migration was observed only at sites in which a grossly intact basal lamina was present.

Mechanisms of gastric mucosal protection in peptic ulcer formation

The purpose of this study is to investigate the relationship between gastric mucosal blood flow (GMBF) and hydrogen ion back diffusion (HBD) during the formation of acute gastric mucosal lesion (AGML) induced by intragastric instillation of gastric mucosal barrier breakers such as HCl and/or ethanol in rats. By increasing the concentration of HCl and/or ethanol in the test solution, the decrease in GMBF became evident 5 minutes after the instillation. This decrease was parallel with the simultaneous increase in the HBD and HCO3- secretion together with the increase in AGML in a dose-response manner. These findings indicate that promotion of HBD is in fact related to the decrease of GMBF in AGML induced by HCl and ethanol. Furthermore, to evaluate the mechanism of the cytoprotection, the effects of 16, 16-dimethyl prostaglandin E2 (16, 16-dmPGE2) on decreased GMBF and promoted HBD during impairment of the gastric mucosal barrier were assessed. In addition, the amount of acid (HCl) neutralized by HCO3- secretion, which was included in the decrease in the HBD, was determined. Administration of 16, 16-dmPGE2 markedly inhibited the formation of gastric lesions macroscopically, but had no significant effects on decreased GMBF. Though promotion of HBD was also inhibited dose-dependently, the HBD did not recover to that of the control group not treated by ethanol. HCO3- secretion was increased dose-dependently by administration of 16, 16-dmPGE2, and its maximal secretion was 10% of the decrease in the acid by HBD. These results show that cytoprotection by 16, 16-dmPGE2 is strongly related to factors other than the improvement of GMBF, such as inhibition of HBD and stimulation of HCO3- secretion.

Prostaglandins and cellular restitution in the gastric mucosa

Topical application of "barrier breakers," including drugs such as aspirin and ethanol, produces widespread destruction of the surface epithelium of the stomach. Such damage does not usually develop into hemorrhagic erosions because the integrity of the surface epithelium is reestablished within a few minutes to hours by the process of epithelial restitution. This process involves active migration of cells from the gastric pits and upper regions of the glands. Restitution is independent of cell division but probably requires an intact basal lamina (basement membrane). The process also depends, in vivo, on adequate microvascular perfusion and can be prevented by high local concentrations of acid. Prostaglandins do not appear to directly affect the restitution process. It is unlikely that prostaglandins either "cytoprotect" the epithelium or accelerate the rate of epithelial migration. Exogenous prostaglandins can, however, protect against the development of hemorrhagic erosions by maintaining an environment in which restitution can proceed. By preventing disruption of the mucosal microvasculature, prostaglandins ensure that the migrating epithelial cells are provided with nutrients and oxygen necessary for cellular activity.

Correlations between changes in indicators of gastric mucosal barrier integrity at time of exposure to "barrier breakers" and extent of hemorrhagic erosions one hour later.

We have examined the effects of seven different "barrier breakers" (including ethanol, aspirin, salicylic acid, isobutyric acid, Na taurocholate, thermal injury, and hyperosmotic glucose) on chambered gastric mucosae of rats in an attempt to identify variations in accepted indicators of mucosal barrier integrity which would accurately predict the extent of subsequent hemorrhagic erosion. When results from all experimental groups were considered, only the initial decrease in transmucosal potential difference (PD) showed significant correlation with final damage (lesion area). When the results were analyzed as separate subgroups, significant correlations were also found between net K+ efflux during the first 10 min after luminal infusion and final lesion area. Only in the subgroup containing ethanol, salicylates, and thermal injury was there a correlation between net loss of luminal H+ (back-diffusion) and lesion area. These results are considered in terms of their implications for the ulcerogenic actions of each group of agents.

Gastric mucosal barrier: hydrophobic lining to the lumen of the stomach.

The contact angle subtended between a droplet of aqueous fluid and nonwettable surfaces provides a direct estimation of their degree of hydrophobicity. The mean contact angle recorded in dogs at the oxyntic mucosal surface was 85.2 degrees, a value characteristic of acid-resistant substances such as polyethylene. This indicates that the mucosal surface of the stomach has a hydrophobic lining that may be attributed to the surface-active phospholipids known to be present in both the gastric mucosa and juice. Barrier breakers such as bile and aspirin were found virtually to eliminate the hydrophobicity. Hydrophobicity was found to be different in the esophagus, antrum, proximal and distal duodenum, and the colon but consistent with their resistance to acid attack. Endogenous surfactants are discussed for their capability to provide a cohesive and strongly adsorbed protective monolayer--a physical model for the gastric mucosal barrier compatible with the major properties of the gastric lining and many features of ulcerogenesis, including the protection afforded by prostaglandins.

Acid back-diffusion and mucosal H+ handling in the rat stomach under normal and stress-induced conditions.

We determined acid back-diffusion and pepsin output simultaneously in vagotomized rats after instillation of HCl into the stomach under normal and stress-induced conditions. With exposure to 6 ml of 100 mM HCl, spontaneous acid back-diffusion increased with the duration of the experiment under both conditions, and the magnitude of the acid back-diffusion was decreased significantly by stress. There was no change in the output of pepsin. While disappearance of luminal acid caused by aspirin or taurocholic acid was not altered by stress, the pepsin output in response to H+ increased significantly in the stressed rats. With exposure to various concentrations of HCl for 3 hr, disappearance of the luminal acid increased linearly with the grade of HCl under both conditions. Except for the concentration of 300 mM, the magnitude of the acid back-diffusion was triple in the normal condition, and the ratio of pepsin output/net flux of H+ was significantly increased by stress. Thus, (1) spontaneous acid back-diffusion decreased with stress, while diffusion induced by chemical barrier breakers remained the same; (2) the action of H+ diffused back into the mucosa did not always parallel the amount of diffusion determined from the loss of H+ in the lumen; (3) intramucosal H+ may be largely dissipated in normal mucosa; and (4) the initiation or aggravation of drug-induced mucosal damages by stress may be related to insufficiency of the H+ dissipating mechanisms.