344 research outputs found
Effect of feedback on the decoherence of a Schrödinger cat state: a quantum trajectory description
No full textThe linear stochastic Schrodinger equation of a cavity mode subject to a homodyne measurement and to a phase-sensitive feedback loop realized with part of the output homodyne photocurrent is derived. We show that quantum feedback has stabilizing effects which manifest themselves in a significant retardation of the decoherence of a Schrodinger-cat state
Tie Makers at Camp
No full textPhotograph - A group standing in the snow in front of a log cabin, Pelican Portage, Alberta. Left to right: unknown, unknown, Elsie Goetsch, Bruno Goetsch, unknown and Joe Laflamm
Tuning tissue ingrowth into pro-angiogenic hydrogels via dual modality degradation
No full textThe potential to control the rate of replacement of a biodegradable implant by a tissue would be advantageous.
Here, we demonstrate that tissue invasion can be tuned through the novel approach of overlaying an enzymatically degradable
hydrogel with an increasingly hydrolytically degradable environment. Poly(ethylene glycol) (PEG) hydrogels were formed from
varying proportions of PEG-vinyl sulfone and PEG-acrylate (PEG-AC) monomers via a Michael-type addition reaction with a
dithiol-containing matrix-metalloproteinase-susceptible peptide cross-linker. Swelling studies showed that PEG hydrogels with
similar initial stiffnesses degraded more rapidly as the PEG-AC content increased. The replacement of subcutaneously
implanted PEG hydrogels was also found to be proportional to their PEG-AC content. In addition, it would in many instances
be desirable that these materials have the ability to stimulate their neovascularization. These hydrogels contained covalently
bound heparin, and it was shown that a formulation of the hydrogel that allowed tissue replacement to occur over 1 month
could trap and release growth factors and increase neovascularization by 50% over that time
The mediational role of FOMO syndrome in the relationship between self-esteem and social media addiction in young adults
No full textPsiholoģijaPsiholoģijaPsychologyPsychologyPētījuma mērķis bija izpētīt, vai FOMO sindroms mediē saistību starp pašvērtējumu un atkarību no sociālajiem tīkliem jauniešiem. Lai sasniegtu mērķi, tika izvirzīti sekojoši pētnieciskie uzdevumi: noskaidrot, vai pastāv saistība starp atkarību no sociāliem tīkliem, FOMO sindromu un pašvērtējumu jauniešiem. Kā arī noskaidrot, vai FOMO sindroms mediē saistību starp pašvērējumu un atakrību no sociālajiem tīkliem jauniešiem. Šajā pētījumā pētnieciskie uzdevumi saskan ar pētījuma jautājumiem.Pētījuma teorētiskais pamatojums balstās uz iepriekšējo pētījumu, kura rezultāti norāda uz to, ka FOMO sindroms ir mediators starp pašvērtējumu un atkarību no Facebook. Tomēr pēdējo desmit gadu laikā ir pieaudzis to jauniešu skaits, kuriem ir atkarība no sociālajiem tīkliem un aktuālā statistika liecina, ka daļa no jauniešiem var nebūt aktīvi Facebook platformas lietotāji, bet izmantot citas sociālo tīklu platformas. Tāpēc šajā pētījumā mediācijas modelī tika izpētīta atkarība no dažādiem sociāliem tīkliem.
Šājā pētījumā piedalījās 230 cilvēki vecumā no 18-25 gadam (M = 20,92; SD = 2,34), no kuriem 50% bija vīrieši. Dati tika ievākti, izmantojot Google veidlapu no 9.02.2024 līdz 15.03.2024. Aptaujā tika izmantotā demogrāfisko datu aptauja, “Sociālo Tīklu Atkarības Skala” (Social Networking Addiction Scale; SNAS; Shahnawaz, M. G., & Rehman, U., 2020; Latvijā šo aptauju ir adaptējusi Fjodorova, P., 2024), “Rozenberga pašcieņas skala” (Rosenberg self- esteem scale, Rosenberg, M., 1965; Latvijā šo aptauju ir adaptējusi Miltuze, A., 1996), ka arī FOMO aptauja (Fear of Missing Out, FoMO; Przybylski, A., Murayama, K., DeHaan, C. & Gladwell, V., 2013; Latvijā šo aptauju ir adaptējusi Goetsch, A., K., 2024). Rezultāti parādīja, ka starp mainīgiem pastāv saistība. Zems pašvērtējums prognozē gan atkarību no sociālajiem tīkliem, gan FOMO sindromu , kas savukārt prognozē atkarību no sociāliem tīkliem. Mediācijas analīze, izmantojot (Baron & Kenny, 1986) metodi parādīja, ka FOMO sindromam ir daļējs nekonsekvents mediācijas efekts uz saistību starp pašvērtējumu un atkarību no sociāliem tīkliem. Tika secināts, ka jauniešiem, kuriem ir zems pašvērtējums salīdzina savus dzīves pieredzes ar apkārtējo dzīves pieredzi, kas rada vēlmi sekot līdzi notikumiem citu dzīvē sociālajos tīklos, kas rezultātā izraisa atkarību no sociāliem tīkliem. Iegūtās zināšanas praktiski var palīdzēt izstrādāt psiholoģiskās intervences, kas mērķēta uz sociālo tīklu atkarību jauniešos.This study aimed to investigate if the FOMO syndrome mediates the relationship between self-esteem and social media addiction in young people. The following research tasks were proposed to achieve the aim: To find out if there is a relationship between social media addiction, self-esteem and FOMO syndrome in young people. Next, to clarify whether the FOMO syndrome mediates the relationship between self-esteem and social media addiction in young people. In this study, the research tasks were consistent with the research issues.The theoretical background of the study is based upon the previous research that has shownthat the FOMO syndrome is a mediator between the self-esteem and Facebook addiction. However, over the past ten years, the number of young people who are addicted to social media has increased, and current statistics show that many young people may not be active users of Facebook platform while actively using other social media platforms. Therefore, in this study, addiction to other social media platforms was investigated within a mediation model.
A total of 230 respondents aged 18 to 25 (M = 20,92; SD = 2,34) took part in this study, 50% of whom were men. Data were collected using Google Forms between 9.02.2024 and 15.03.2024. Respondents reported demographic information, completed “Social Networking Addiction Scale”; SNAS; Shahnawaz, M. G., & Rehman, U., 2020.; In Latvia, this survey was adapted by Fyodorova, P., 2024, “Rosenberg self-esteem scale” Rosenberg, M., 1965; In Latvia this survey was adapted by Miltuze, A., 1996, as well as the FOMO survey “Fear of Missing Out, FoMO”; Przybylski, A., Murayama, K., DeHaan, C. & Gladwell, V., 2013; In Latvia this survey was adapted by Goetsch, A., K., 2024.
The results show that there is a relationship between the variables. Self-esteem predicts both the social media addiction and the FOMO syndrome, which in turn predicts social media addiction. Furthermore, mediation analysis using Baron & Kenny (1986) method showed that FOMO has a partial and inconsistent mediation effect on the relationship between self-esteem and social media addiction. It was concluded that young people with low self-esteem compare their life experiences with the life experiences of others, which creates a desire to follow events in their lives on social networks, which in turn results in the addiction to social networks. The acquired knowledge can practically help to develop psychological interventions aimed at social network addiction for young people
Synthetic extracellular matrix mimic hydrogel improves efficacy of mesenchymal stromal cell therapy for ischemic cardiomyopathy.
No full textBACKGROUND:
Mesenchymal stromal cells (MSC) repair infarcted hearts mainly through paracrine mechanisms. Low cell engraftment limits the release of soluble paracrine factors (SF) over time and, consequently, MSC efficacy. We tested whether a synthetic extracellular matrix mimic, a hydrogel containing heparin (H-HG), could ameliorate MSC engraftment and binding/release of SF, thus improving MSC therapy efficacy.
METHODS AND RESULTS:
In vitro, rat bone-marrow MSC (rBM-MSC) were seeded and grown into H-HG. Under normoxia, the hydrogel did not affect cell survival (rBM-MSC survival >90% at each time point tested); vice versa, under hypoxia the biomaterial resulted to be protective for the cells (p < .001 vs rBM-MSC alone). H-HG or control PEG hydrogels (HG) were incubated with VEGF or bFGF for binding/release quantification. Data showed significantly higher amount of VEGF and bFGF bound by H-HG compared with HG (p < .05) and a constant release over time. In vivo, myocardial infarction (MI) was induced in female Sprague Dawley rats by permanent coronary ligation. One week later, saline, rBM-MSC, H-HG or rBM-MSC/H-HG were injected in the infarct zone. The co-injection of rBM-MSC/H-HG into infarcted hearts significantly increased cardiac function. Importantly, we observed a significant gain in MSC engraftment, reduction of ventricular remodeling and stimulation of neo-vasculogenesis. We also documented higher amounts of several pro-angiogenic factors in hearts treated with rBM-MSC/H-HG.
CONCLUSIONS:
Our data show that H-HG increases MSC engraftment, efficiently fine tunes the paracrine MSC actions and improves cardiac function in infarcted rat hearts.
STATEMENT OF SIGNIFICANCE:
Transplantation of MSC is a promising treatment for ischemic heart disease, but low cell engraftment has so far limited its efficacy. The enzymatically degradable H-HG that we developed is able to increase MSC retention/engraftment and, at the same time, to fine-tune the paracrine effects mediated by the cells. Most importantly, the co-transplantation of MSC and H-HG in a rat model of ischemic cardiomyopathy improved heart function through a significant reduction in ventricular remodeling/scarring and amelioration in neo-vasculogenesis/endogenous cardiac regeneration. These beneficial effects are comparable to those obtained by others using a much greater number of cells, strengthening the efficacy of the biomaterial used in increasing the therapeutic effects of MSC. Given its efficacy and safety, documented by the absence of immunoreaction, our strategy appears readily translatable to clinical scenarios
Determining hydrogen peroxide exposure of employees at Company XYZ
No full textPlan BThe significance of this study stems from the plethora of health effects associated with the exposure of industrial hydrogen peroxide concentrations. An extensive literature review established the serious health effects resulting from both acute and chronic hydrogen peroxide exposure. Monitoring was performed using Draeger-Tubes® and a Pac III measuring device. Previous Draeger-Tube® and time weighted average data was also obtained to help make informed conclusions. Results lead the researcher to conclude that employees at Company XYZ are being overexposed to hydrogen peroxide only during the start-up stage when the equipment is being sterilized. Several control options are recommended for consideration, each having benefits as well as concerns. Engineering controls are preferred, but respiratory protection usage is practical under the circumstances. The study found that the threat of hydrogen peroxide overexposure is in fact true at certain operational stages and that such exposure may lead to serious health effects in future
Bus Transit Dwell Time Under a Complex Fare Structure and Bus Transit On-Time Performance
No full textIn the years to come, federal financial aid to mass transit most likely will be cut to reduce the federal budget deficit. Facing this problem, the mass transit industry is looking for ways to accommodate the losses. Two methods of improving bus service will be examined in this thesis. This thesis is divided into two parts. The first part (Chapters 2 and 3) deals with the effect on bus passenger dwell time from a complicated fare structure, using the Southeastern Michigan Transportation Authority (SEMTA) as a case study. The SEMTA, which serves more than 750,000 people in suburban Detroit, uses a zone fare system. Separate analyses were conducted for alighting and boarding. First, a comparison of boarding times as a function of fare payment method was made. Next, regression analyses were performed to find the relationship between alighting or boarding times and the number of passengers. Finally, the distribution of overall dwell times was determined. The second part of the thesis (Chapters 4 and 5) deals with bus transit on-time performance. The Milwaukee County Transit System was chosen for this study. Frequency and other statistical packages of SPSSx were used to analyze the data. An analysis was performed to compare the arriving times at different points along a route, at different times of day, and in different directions. Also, an analysis was made to find the probability distribution of on-time performance
Implementing Distance-Based Fares on Bus Transit
No full textPresently, the bus transit industry of the United States is facing stiff challenges caused by fiscal constraints. Rising operating deficits in urban bus transit have necessitated an increased external fiscal support. The Federal government is continually providing financial assistance to the transit industry. A major challenge faced by the industry is to provide needed service in the most efficient and equitable manner. Distance-based fare structures are considered to provide the greatest equity to the passengers. However, implementation of distance based fare structures requires sophisticated fare collection equipment. Interest in implementing equitable fare structures has prompted the research need to explore the possibilities of instituting distance-based fare structures
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