198 research outputs found
Production of levulinic acid from wet microalgae in a biphasic one-pot reaction processs
No full textThis work addresses the conversion of wet microalgae to levulinic acid (LA) using a one-pot reaction system. Utilizing moisture in microalgae forms a biphasic system with an organic solvent of 1, 2-dichloroethane (DCE) is formed. This system enhances the LA yield by making an acidic environment through the decomposition of DCE in a small quantity and the recovery of products in each aqueous and organic phase. With lipid-richNannochloropsis gaditanaand carbohydrate-richChlorellaspecies, the effects of reaction variables of temperature, water content, and DCE dosage on the LA production were investigated. The LA yield was 30.13 wt% and 28.15 wt% based on the mass of total hexoses (43-47 wt% of convertible hexoses) for the two types of microalgae at 160 degrees C, while the yield of free fatty acids reached 90.13 w/w% at 180 degrees C based on the esterifiable lipid. This biphasic system facilitates the forward reaction and the product recovery for concurrent reaction and separation.
Systematicaly Programmed Adaptive Evolution Revealed the Ptential Role of Carbon and Nitrogen Pathways during Lipid Accumulation in Chlamidomonas reinhardtii
No full textMengapa Bumi Semakin Panas?
No full textSemua berawal dari pendidkan yang berhubungan dengan rasa ingin tahu akan berbagai macam fenomena yang muncul di dalam kehidupan sehari- hari , sangat menarik untuk anak-anak agar mereka terbiasa mengeksplorasi sendiri. Minji datang dari masa depan. Bersama Thunder, robotnya, dia pergi ke masa lalu dengan mesin waktu. Mereka mencari tahu mengapa Bumi Masa depan dipenuhi lautan. Ternyata, di bumi masa lalu terjadi pemanasan global. Hal itu terjadi karena gas karbondioksida dan metana terperangkap di bumi, sehingga bumi lebih panas seperti rumah kaca. Akhirnya, minji tahu hal tersebut menyebabkan masalah-masalah serius, seperti gletser-gletser yang mecair. Kita ikuti kisah minji dan thunder.37 hlm; 21,5x28 c
Network coding for speedup in switches
No full textThesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Includes bibliographical references (p. 69-71).Network coding, which allows mixing of data at intermediate network nodes, is known to increase the throughput of networks. In particular, it is known that linear network coding in a crossbar switch can sustain traffic patterns that cannot be served if network coding were not allowed. Thus, network coding leads to a larger rate region in a multicast crossbar switch. This thesis quantities the gain in rate region in a multicast crossbar switch in terms of speedup. We present a graph theoretic upper bound on speedup needed to achieve 100% throughput in a multicast switch using network coding. By bounding speedup, we show the equivalence between network coding and speedup in multicast switches - i.e. network coding, which is usually implemented using software, can in many cases substitute speedup, which is often achieved by adding extra switch fabrics. This bound is based on an approach to network coding problems called the "enhanced conflict graph". We show that the "imperfection ratio" of the enhanced conflict graph gives an upper bound on speedup. In particular, we apply this result to K x N switches with traffic patterns consisting of unicasts and broadcasts only to obtain an upper bound of min(2K-1/K, 2N/N+1).by MinJi Kim.M.Eng
COPING WITH MULTIPLE STRESSORS: A CLOSER LOOK AT PSYCHOLOGICAL DISTRESS AMONG RACIAL MINORITIES
No full textThis study examined a comprehensive stress and coping model in a sample of 414 racial minority participants in the U.S. Specifically, this study looked at main effects: a) racism-related stress, b) financial stress, c) problem-solving coping, d) avoidance coping and interaction effects: e) racism-related stress and financial stress, f) racism-related stress and problem-solving, g) racism-related stress and avoidance coping, h) financial stress and problem-solving coping, and i) financial stress and avoidance coping in relation to psychological distress in a comprehensive model. A latent variable path analysis of the comprehensive model and post-hoc latent variable path analyses were conducted after diving the larger model into three smaller models. The results showed that racism-related stress, financial stress, and avoidance coping were significant predictors of psychological distress. Moreover, problem-solving coping worked as a significant moderator and stress-buffer between racism-related stress and psychological distress. An extensive literature review of conceptual and methodological elements of the study constructs are presented. Limitations of this study as well as future directions in research and clinical practice are also included
Puerto Rico’s Attempts to Address a Public Health Crisis Struck Down by the United States Court of Appeals for the First Circuit
No full textThis RCD discusses a recent decision by the United States Court of Appeals for the First Circuit that struck down Puerto Rico’s Act 90-2019, which aimed to regulate pay structures for Medicare Advantage insurers in Puerto Rico. The court found that the provision in Act 90, known as the “Mandated Price Provision,” is preempted by federal law. However, the author argues that the court’s decision did not adequately consider the congressional intent of the Medicare Advantage Act in weighing the public health crisis in Puerto Rico. The RCD provides background on the Medicare Advantage program and Act 90 and explains how Act 90 aimed to eliminate insurers’ practice of paying providers at rates below the CMS’s minimum reimbursement rates under the traditional Medicare program. The article concludes that the court’s decision inadequately considered the larger purpose of the Medicare Advantage Act and the relevant public health crisis in Puerto Rico.Published versio
Moving Forward: Addressing stress, positive resources, and gender
No full textThis study examined a comprehensive stress-buffering model in a sample of 200 college students. Specifically, this study looked at social support and optimism as moderators between different types of stress and psychological health while controlling for gender given prior research that has demonstrated gender differences among the study constructs. Hierarchical regression analyses found that social support, but not optimism, worked as a significant moderator between different stressors, developmental challenge stress, time pressure stress, and social mistreatment stress, and psychological health. Supplemental analyses found in an independent samples t-test analysis that female college students had higher mean levels of time pressure stress than male college students. An extensive literature review of the study constructs including conceptual and methodological information and areas of improvement are delineated. Limitations of this study as well as future directions in research and clinical practice are also included
Dietary antigens limit mucosal immunity by inducing regulatory T cells in the small intestine
No full textDietary antigens are normally rendered nonimmunogenic through a poorly understood "oral tolerance" mechanism that involves immunosuppressive regulatory T (T-reg) cells, especially Treg cells induced from conventional T cells in the periphery (pT(reg) cells). Although orally introducing nominal protein antigens is known to induce such pTreg cells, whether a typical diet induces a population of pT(reg) cells under normal conditions thus far has been unknown. By using germ-free mice raised and bred on an elemental diet devoid of dietary antigens, we demonstrated that under normal conditions, the vast majority of the small intestinal pT(reg) cells are induced by dietary antigens from solid foods. Moreover, these pT(reg) cells have a limited life span, are distinguishable from microbiota-induced pT(reg) cells, and repress underlying strong immunity to ingested protein antigens.1110976Nsciescopu
Factors Influencing Preventive Behavior of COVID-19 among Nursing Students in South Korea
No full textWe aimed to identify factors influencing the preventive behavior of COVID-19 among nursing students. A survey was conducted through an online questionnaire in December 2021 for students in the department of nursing at a university located in C city. An online questionnaire was distributed to 189 nursing students who voluntarily agreed to participate in the study, and data from 179 of them were used for the final analysis. The research tools used were COVID-19 stress scale for Korean people, COVID-19 risk-perception scale, self-efficacy scale, and COVID-19 prevention behavior scale. Data were analyzed by descriptive statistics, t-test, analysis of variance, Mann–Whitney and Kruskal–Wallis test, as well as Spearman correlation coefficient and multiple linear regression with SPSS 23.0 program. Factors significantly influencing the preventive behavior of COVID-19 were self-efficacy (β = 0.53, p < 0.001) and COVID-19 stress (β = 0.25, p = 0.001). The explanatory power of related variables was 45.0%. We found that self-efficacy and COVID-19 stress had a significant effect on the preventive behavior of nursing students. Therefore, to promote the preventive behavior of COVID-19, it is necessary to improve the self-efficacy of nursing students and manage COVID-19 stress well
Collective magnetic Higgs excitation in a pyrochlore ruthenate
No full textThe emergence of scalar Higgs-type amplitude modes in systems where symmetry
is spontaneously broken has been a highly successful, paradigmatic description
of phase transitions, with implications ranging from high-energy particle
physics to low-energy condensed matter systems. Here, we uncover two successive
high temperature phase transitions in the pyrochlore magnet NdRuO
at K and K, that lead to giant phonon
instabilities and culminate in the emergence of a highly coherent excitation.
This coherent excitation, distinct from other phonons and from conventional
magnetic modes, stabilizes at a low energy of 3 meV. We assign it to a
collective Higgs-type amplitude mode, that involves bond energy modulations of
the Ru tetrahedra. Its striking two-fold symmetry, incompatible with the
underlying crystal structure, highlights the possibility of multiple entangled
broken symmetries
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