306 research outputs found
Immigration Federalism: A Reappraisal
This Article identifies how the current spate of state and local regulation is changing the way elected officials, scholars, courts, and the public think about the constitutional dimensions of immigration law and governmental responsibility for immigration enforcement. Reinvigorating the theoretical possibilities left open by the Supreme Court in its 1875 Chy Lung v. Freeman decision, state and local offi- cials characterize their laws as unavoidable responses to the policy problems they face when they are squeezed between the challenges of unauthorized migration and the federal government’s failure to fix a broken system. In the October 2012 term, in Arizona v. United States, the Court addressed, but did not settle, the difficult empirical, theoretical, and constitutional questions necessitated by these enactments and their attendant justifications. Our empirical investigation, however, discovered that most state and local immigration laws are not organic policy responses to pressing demographic challenges. Instead, such laws are the product of a more nuanced and politicized process in which demographic concerns are neither neces- sary nor sufficient factors and in which federal inactivity and subfederal activity are related phenomena, fomented by the same actors. This Article focuses on the con- stitutional and theoretical implications of these processes: It presents an evidence- based theory of state and local policy proliferation; it cautions legal scholars to rethink functionalist accounts for the rise of such laws; and it advises courts to reassess their use of traditional federalism frameworks to evaluate these sub federal enactments
Specifying computer-supported collaboration scripts
Collaboration scripts are activity programs which aim to foster collaborative learning by structuring interaction between learners. Computer-supported collaboration scripts generally suffer from the problem of being restrained to a specific learning platform and learning context. A standardization of collaboration scripts first requires a specification of collaboration scripts that integrates multiple perspectives from computer science, education and psychology. So far, only few and limited attempts at such specifications have been made. This paper aims to consolidate and expand these approaches in light of recent findings and to propose a generic framework for the specification of collaboration scripts. The framework enables a description of collaboration scripts using a small number of components (participants, activities, roles, resources and groups) and mechanisms (task distribution, group formation and sequencing)
Collaboration scripts - a conceptual analysis
This article presents a conceptual analysis of collaboration scripts used in face-to-face and computer-mediated collaborative learning. Collaboration scripts are scaffolds that aim to improve collaboration through structuring the interactive processes between two or more learning partners. Collaboration scripts consist of at least five components: (a) learning objectives, (b) type of activities, (c) sequencing, (d) role distribution, and (e) type of representation. These components serve as a basis for comparing prototypical collaboration script approaches for face-to-face vs. computer-mediated learning. As our analysis reveals, collaboration scripts for face-to-face learning often focus on supporting collaborators in engaging in activities that are specifically related to individual knowledge acquisition. Scripts for computer-mediated collaboration are typically concerned with facilitating communicative-coordinative processes that occur among group members. The two lines of research can be consolidated to facilitate the design of collaboration scripts, which both support participation and coordination, as well as induce learning activities closely related to individual knowledge acquisition and metacognition. In addition, research on collaboration scripts needs to consider the learners’ internal collaboration scripts as a further determinant of collaboration behavior. The article closes with the presentation of a conceptual framework incorporating both external and internal collaboration scripts
Evaluating teaching effectiveness in nursing education:An Iranian perspective
BACKGROUND: The main objective of this study was to determine the perceptions of Iranian nurse educators and students regarding the evaluation of teaching effectiveness in university-based programs. METHODS: An exploratory descriptive design was employed. 143 nurse educators in nursing faculties from the three universities in Tehran, 40 undergraduate, and 30 graduate students from Tehran University composed the study sample. In addition, deans from the three nursing faculties were interviewed. A researcher-developed questionnaire was used to determine the perceptions of both faculty and students about evaluating the teaching effectiveness of nurse educators, and an interview guide was employed to elicit the views of deans of faculties of nursing regarding evaluation policies and procedures. Data were analyzed using parametric and nonparametric statistics to identify similarities and differences in perceptions within the Iranian nurse educator group and the student group, and between these two groups of respondents. RESULTS: While faculty evaluation has always been a major part of university based nursing programs, faculty evaluation must be approached more analytically, objectively, and comprehensively to ensure that all nursing educators receive the fairest treatment possible and that the teaching-learning process is enhanced. CONCLUSION: Educators and students stressed that systematic and continuous evaluation as well as staff development should be the primary goals for the faculty evaluation process. The ultimate goals is the improvement of teaching by nurse educators
Discovery of a novel inner membrane-associated bacterial structure related to the flagellar type III secretion system
Microbial Biotechnolog
Ignicoccus hospitalis and Nanoarchaeum equitans: ultrastructure, cell–cell interaction, and 3D reconstruction from serial sections of freeze-substituted cells and by electron cryotomography
Ultrastructure and intercellular interaction of Ignicoccus hospitalis and Nanoarchaeum equitans were investigated using two different electron microscopy approaches, by three-dimensional reconstructions from serial sections, and by electron cryotomography. Serial sections were assembled into 3D reconstructions, for visualizing the unusual complexity of I. hospitalis, its huge periplasmic space, the vesiculating cytoplasmic membrane, and the outer membrane. The cytoplasm contains fibres which are reminiscent to a cytoskeleton. Cell division in I. hospitalis is complex, and different to that in Euryarchaeota or Bacteria. An irregular invagination of the cytoplasmic membrane is followed by separation of the two cytoplasms. Simultaneous constriction of cytoplasmic plus outer membrane is not observed. Cells of N. equitans show a classical mode of cell division, by constriction in the mid-plane. Their cytoplasm exhibits two types of fibres, elongated and ring-shaped. Electron micrographs of contact sites between I. hospitalis and N. equitans exhibit two modes of interaction. One is indirect and mediated by thin fibres; in other cells the two cell surfaces are in direct contact. The two membranes of I. hospitalis cells are frequently seen in direct contact, possibly a prerequisite for transporting metabolites or substrates from the cytoplasm of one cell to the other. Rarely, a transport based on cargo vesicles is observed between I. hospitalis and N. equitans
Genome-Wide Mutagenesis of Xanthomonas axonopodis pv. citri Reveals Novel Genetic Determinants and Regulation Mechanisms of Biofilm Formation
Xanthomonas axonopodis pv. citri (Xac) causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale study of Xac biofilm formation in which we identified 92 genes, including 33 novel genes involved in biofilm formation and 7 previously characterized genes, colR, fhaB, fliC, galU, gumD, wxacO, and rbfC, known to be important for Xac biofilm formation. In addition, 52 other genes with defined or putative functions in biofilm formation were identified, even though they had not previously reported been to be associated with biofilm formation. The 92 genes were isolated from 292 biofilm-defective mutants following a screen of a transposon insertion library containing 22,000 Xac strain 306 mutants. Further analyses indicated that 16 of the novel genes are involved in the production of extracellular polysaccharide (EPS) and/or lipopolysaccharide (LPS), 7 genes are involved in signaling and regulatory pathways, and 5 genes have unknown roles in biofilm formation. Furthermore, two novel genes, XAC0482, encoding a haloacid dehalogenase-like phosphatase, and XAC0494 (designated as rbfS), encoding a two-component sensor protein, were confirmed to be biofilm-related genes through complementation assays. Our data demonstrate that the formation of mature biofilm requires EPS, LPS, both flagellum-dependent and flagellum-independent cell motility, secreted proteins and extracellular DNA. Additionally, multiple signaling pathways are involved in Xac biofilm formation. This work is the first report on a genome-wide scale of the genetic processes of biofilm formation in plant pathogenic bacteria. The report provides significant new information about the genetic determinants and regulatory mechanism of biofilm formation
Training in crisis communication and volcanic eruption forecasting:Design and evaluation of an authentic role-play simulation
We present an interactive, immersive, authentic role-play simulation designed to teach tertiary geoscience students
in New Zealand to forecast and mitigate a volcanic crisis. Half of the participating group (i.e., the Geoscience Team)
focuses on interpreting real volcano monitoring data (e.g., seismographs, gas output etc.) while the other half of the
group (i.e., the Emergency Management Team) forecasts and manages likely impacts, and communicates emergency
response decisions and advice to local communities. These authentic learning experiences were aimed at enhancing
upper-year undergraduate students’ transferable and geologic reasoning skills. An important goal of the simulation was
specifically to improve students’ science communication through interdisciplinary team discussions, jointly prepared,
and delivered media releases, and real-time, high-pressure, press conferences.
By playing roles, students experienced the specific responsibilities of a professional within authentic organisational
structures. A qualitative, design-based educational research study was carried out to assess the overall student experience
and self-reported learning of skills. A pilot and four subsequent iterations were investigated.
Results from this study indicate that students found these role-plays to be a highly challenging and engaging learning
experience and reported improved skills. Data from classroom observations and interviews indicate that the students
valued the authenticity and challenging nature of the role-play although personal experiences and team dynamics
(within, and between the teams) varied depending on the students’ background, preparedness, and personality.
During early iterations, observation and interviews from students and instructors indicate that some of the goals of the
simulation were not fully achieved due to: A) lack of preparedness, B) insufficient time to respond appropriately, C)
appropriateness of roles and team structure, and D) poor communication skills. Small modifications to the design of
Iterations 3 and 4 showed an overall improvement in the students’ skills and goals being reached.
A communication skills instrument (SPCC) was used to measure self-reported pre- and post- communication competence
in the last two iterations. Results showed that this instrument recorded positive shifts in all categories of self-perceived
abilities, the largest shifts seen in students who participated in press conferences. Future research will be aimed
at adapting this curricula to new volcanic and earthquake scenarios
Leitura/compreensão, escrita e sucesso acadêmico: um estudo de diagnóstico em quatro universidades portuguesas
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