30 research outputs found
Stable two-dimensional dispersion-managed soliton
The existence of a dispersion-managed soliton in two-dimensional nonlinear
Schr\"odinger equation with periodically varying dispersion has been explored.
The averaged equations for the soliton width and chirp are obtained which
successfully describe the long time evolution of the soliton. The slow dynamics
of the soliton around the fixed points for the width and chirp are investigated
and the corresponding frequencies are calculated. Analytical predictions are
confirmed by direct PDE and ODE simulations. Application to a Bose-Einstein
condensate in optical lattice is discussed. The existence of a
dispersion-managed matter-wave soliton in such system is shown.Comment: 4 pages, 3 figures, Submitted to Phys. Rev.
Seek Help from Teachers or Fight Back? Student Perceptions of Teachersâ Actions during Conflicts and Responses to Peer Victimization
Previous research has shown that teachersâ actions when addressing conflict on school grounds can shape adolescent perceptions regarding how well the school manages victimization. Our objective in this study was to determine how these perceptions influenced the likelihood that adolescent students would react to victimization scenarios by either seeking help from school authority or physically fighting back. Vignettes describing two events of victimization were administered to 148 ethnic minority adolescents (Latino, African American, and Asian backgrounds; 49% female) attending an urban high school with high rates of conflict. Positive perceptions of teachersâ actions during conflictsâassessed via a questionnaire tapping how teachers manage student conflicts both generally and in a specific instance of strifeâpredicted a greater willingness to seek help from school authority, which in turn negatively predicted self-reported aggressive responses to the victimization scenarios. Path analysis established the viability of this indirect effect model, even when we controlled for sex, beliefs about the acceptability of aggression, and previous levels of reactive aggression. Adolescentsâ perceptions of teachersâ actions during conflicts are discussed in relation to social information processing models, improving studentâteacher relations, and decreasing aggression at schools
Type 2 Immunity and Age Modify Gene Expression of COVID19 Receptors in Eosinophilic Gastrointestinal Disorders
Infection with SARS-CoV-2 can lead to COVID-19. The gastrointestinal tract is now an appreciated portal of infection. SARS-CoV-2 enters host cells via angiotensin converting enzyme-2 (ACE2) and the serine protease TMPRSS2. Eosinophilic gastrointestinal disorders are inflammatory conditions caused by chronic type 2 (T2) inflammation. However, the effects of the T2 atopic inflammatory milieu on SARS-COV-2 viral entry gene expression in the GI tract is poorly understood. We analyzed tissue ACE2 and TMPRSS2 gene expression in pediatric eosinophilic esophagitis (EoE), eosinophilic gastritis (EG) and in normal adult esophagi using publicly available RNA sequencing datasets. Similar to findings evaluating the airway, there was no difference in tissue ACE2/TMPRSS2 expression in EoE or EG when compared to control non-EoE/EG esophagus/stomach. ACE2 gene expression was significantly lower in esophagi from children with or without EoE and from adults with EoE as compared to normal adult esophagi. Type 2 immunity and pediatric age could be protective for infection by SARS-CoV-2 in the gastrointestinal tract due to decreased expression of ACE2
THE A H1N1 INFLUENZA PANDEMIC. A SYSTEMIC ANALYSIS OF ITS GENESIS, EVOLUTION AND SOCIO-ECONOMIC, CULTURAL AND HEALTH CONSEQUENCES IN MEXICO
<!-- /* Font Definitions */ @font-face {font-family:"Cambria Math"; panose-1:2 4 5 3 5 4 6 3 2 4; mso-font-charset:0; mso-generic-font-family:roman; mso-font-pitch:variable; mso-font-signature:-1610611985 1107304683 0 0 159 0;} @font-face {font-family:Calibri; panose-1:2 15 5 2 2 2 4 3 2 4; mso-font-charset:0; mso-generic-font-family:swiss; mso-font-pitch:variable; mso-font-signature:-1610611985 1073750139 0 0 159 0;} /* Style Definitions */ p.MsoNormal, li.MsoNormal, div.MsoNormal {mso-style-unhide:no; mso-style-qformat:yes; mso-style-parent:""; margin-top:0cm; margin-right:0cm; margin-bottom:10.0pt; margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-fareast-font-family:Calibri; mso-bidi-font-family:"Times New Roman"; mso-ansi-language:ES-MX; mso-fareast-language:EN-US;} .MsoChpDefault {mso-style-type:export-only; mso-default-props:yes; font-size:10.0pt; mso-ansi-font-size:10.0pt; mso-bidi-font-size:10.0pt; mso-ascii-font-family:Calibri; mso-fareast-font-family:Calibri; mso-hansi-font-family:Calibri;} @page Section1 {size:612.0pt 792.0pt; margin:70.85pt 3.0cm 70.85pt 3.0cm; mso-header-margin:36.0pt; mso-footer-margin:36.0pt; mso-paper-source:0;} div.Section1 {page:Section1;} --> In April 2009 a health emergency was declared in Mexico City, as a new influenza virus (AH1N1) began to spread. This new virus was similar to the Spanish Influenza virus which caused the death of more than 40 million persons in 1918-1919. The 2009 health emergency declaration in Mexico imposed the suspension of activities in crowded areas such as schools, restaurants, sports and recreational areas, during several days, causing important economic loses and deep seated fears in many persons. This paper presents a systemic analysis of the genesis and evolution of this pandemic and proposes some preliminary conclusions and recommendations. This pandemic situation was not as grave as expected, but the alert flags continue to be raised, at the world level, because the spread a very dangerous influenza epidemic is feared by the World Health Organization specialists
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Seek Help from Teachers or Fight Back? Student Perceptions of Teachersâ Actions during Conflicts and Responses to Peer Victimization
Previous research has shown that teachersâ actions when addressing conflict on school grounds can shape adolescent perceptions regarding how well the school manages victimization. Our objective in this study was to determine how these perceptions influenced the likelihood that adolescent students would react to victimization scenarios by either seeking help from school authority or physically fighting back. Vignettes describing two events of victimization were administered to 148 ethnic minority adolescents (Latino, African American, and Asian backgrounds; 49% female) attending an urban high school with high rates of conflict. Positive perceptions of teachersâ actions during conflictsâassessed via a questionnaire tapping how teachers manage student conflicts both generally and in a specific instance of strifeâpredicted a greater willingness to seek help from school authority, which in turn negatively predicted self-reported aggressive responses to the victimization scenarios. Path analysis established the viability of this indirect effect model, even when we controlled for sex, beliefs about the acceptability of aggression, and previous levels of reactive aggression. Adolescentsâ perceptions of teachersâ actions during conflicts are discussed in relation to social information processing models, improving studentâteacher relations, and decreasing aggression at schools
Recommended from our members
Type 2 Immunity and Age Modify Gene Expression of Coronavirus-induced Disease 2019 Receptors in Eosinophilic Gastrointestinal Disorders.
Infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) can lead to coronavirus-induced disease 2019 (COVID-19). The gastrointestinal (GI) tract is now an appreciated portal of infection. SARS-CoV-2 enters host cells via angiotensin-converting enzyme-2 (ACE2) and the serine protease TMPRSS2. Eosinophilic gastrointestinal disorders (EGIDs) are inflammatory conditions caused by chronic type 2 (T2) inflammation. the effects of the T2 atopic inflammatory milieu on SARS-COV-2 viral entry gene expression in the GI tract is poorly understood. We analyzed tissue ACE2 and TMPRSS2 gene expression in pediatric eosinophilic esophagitis (EoE), eosinophilic gastritis (EG), and in normal adult esophagi using publicly available RNA-sequencing datasets. Similar to findings evaluating the airway, there was no difference in tissue ACE2/TMPRSS2 expression in EoE or EG when compared with control non-EoE/EG esophagus/stomach. ACE2 gene expression was significantly lower in esophagi from children with or without EoE and from adults with EoE as compared with normal adult esophagi. Type 2 immunity and pediatric age could be protective for infection by SARS-CoV-2 in the gastrointestinal tract because of decreased expression of ACE2