Search results for "41"
showing 10 items of 3365 documents
Rotational State Change of Acetonitrile Vapor on MCM-41 upon Capillary Condensation with the aid of Time-Correlation Function Analysis of IR Spectros…
2000
The infrared spectra of adsorbed acetonitrile on MCM-41 (porewidth = 3.2 nm) were measured at 303 K. In the CN stretching ν2 region, two bands were observed at 2265 cm− 1 and 2254 cm− 1, assigned to hydrogen-bonded molecules on surface hydroxyls of MCM-41, and physisorbed molecules in mesopores, respectively. We designate here the 2265 cm− 1 band as the ν2α band and the 2254 cm− 1 band as the ν2β band. The bandwidth of the fundamental transition ν2fβ, was obtained by removing the overlap with hot band transitions of the same mode, ν2α band, and other modes by least-squares fitting. Before capillary condensation, the relaxation time τ obtained from the bandwidth of the ν2fβ band was smaller …
Synthesis of novel fluorinated building blocks via halofluorination and related reactions.
2020
A study exploring halofluorination and fluoroselenation of some cyclic olefins, such as diesters, imides, and lactams with varied functionalization patterns and different structural architectures is described. The synthetic methodologies were based on electrophilic activation through halonium ions of the ring olefin bonds, followed by nucleophilic fluorination with Deoxo-Fluor®. The fluorine-containing products thus obtained were subjected to elimination reactions, yielding various fluorine-containing small-molecular entities.
Ring-opening metathesis of some strained bicyclic systems; stereocontrolled access to diolefinated saturated heterocycles with multiple stereogenic c…
2018
Ring-opening metathesis (ROM) of various unsaturated, constrained bicyclic ring systems has been investigated with the use of commercial ruthenium-based catalysts. Starting from various cyclodienes, the corresponding derived bicyclic lactone, lactam, and isoxazoline derivatives were submitted to ROM under ethenolysis. These functionalized, strained bicyclic systems afforded novel highly-functionalized diolefinated heterocyclic scaffolds in ROM reactions with stereocontrol, through the conservation of the configuration of the stereogenic centers of the starting compounds.
Guardia y custodia compartida impuesta
2018
Cuando una pareja con hijos comunes menores de edad deja de convivir surge la necesidad de determinar las reglas o normas por las que se regirá la nueva situación familiar. Estas normas pueden ser de carácter económico o personal. Entre las personales, y una sobre las que más les cuesta decidir a los progenitores, es la relativa al cuidado de los hijos y a cómo se va a dar continuidad a las relaciones con ellos una vez se haya producido la separación. Lo mejor sería que los propios progenitores pudieran llegar a un acuerdo al respecto ya que ellos son los que mejor conocen a sus hijos y los mejores conocedores de la situación que están viniendo. Pero en defecto de acuerdo será necesario det…
La mafia come metodo e come fine: la circostanza aggravante dell'art. 7 d.l. 152/1991, convertito nella l. 203/1991
2008
Sommario: 1. Considerazioni introduttive. - 2. La circostanza aggravante c.d. del metodo mafioso: una rilettura “territoriale”. Il contesto sociale come supporto ermeneutico per la valutazione dell’idoneità della condotta. - 2.1. La “cerchia dei destinatari” dell’aggravante del metodo mafioso. Compatibilità tecnico-giuridica con la partecipazione all’associazione mafiosa (art. 416 bis c.p.). - 3. La variante dell’agevolazione mafiosa. Il delitto-base come “morfema” materiale della finalità agevolatrice? - 3.1. Segue: l’accertamento di un «coefficiente di idoneità obiettiva» o di «pericolosità potenziale». - 3.2 La “cerchia dei destinatari” dell’aggravante dell’agevolazione mafiosa. Compatib…
Highly cited educational technology journal articles: A descriptive and critical analysis
2022
Citations are valuable capital in the academy as the number of citations is the most frequently used indicator in evaluating the quality of papers, journals, researchers, and universities. Thus, the characteristics of highly cited articles (HCA) have become a common research topic but the approach has been mainly descriptive with no profound critical reflection of what kind of research is cited, where the research is from, where the research is published, and what do these things mean for edtech research. This paper contributes to this need by providing a descriptive and critical analysis of 200 highly cited articles from 10 edtech journals. To summarize the key findings, a ‘typical’ edtech…
¿Quién decide qué y cómo? el conflicto en torno a la participación ciudadana en el contexto del desarrollo de la iniciativa urbana: Cuenca-San Antón …
2018
This article describes the main results of an ethnographic study on citizen participation carried out in the context of the development of the Urban Initiative (2007-2015): Cuenca-Barrio de San Antón. Managed by the City Council of Cuenca and financed by the European Regional Development Funds (FEDER) under the Ministry of Economy and Finance at the Government of Spain The results of the research show how in the context of the application of neoliberal policies, citizen participation becomes the trigger for new conflicts between institutions and citizens. In this sense, it is worth noting how, in practice, institutions in their capacity as experts and not willing to dis-empower themselves, …
Multiscale variation in drought controlled historical forest fire activity in the boreal forests of eastern Fennoscandia
2017
Forest fires are a key disturbance in boreal forests, and characteristics of fire regimes are among the most important factors explaining the variation in forest structure and species composition. The occurrence of fire is connected with climate, but earlier, mostly local-scale studies in the northern European boreal forests have provided little insight into fire-climate relationship before the modern fire suppression period. Here, we compiled annually resolved fire history, temperature, and precipitation reconstructions from eastern Fennoscandia from the mid-16th century to the end of the 19th century, a period of strong human influence on fires. We used synchrony of fires over the network…
Long-term decrease in Asian monsoon rainfall and abrupt climate change events over the past 6,700 years
2021
Significance The variability of the Asian summer monsoon (ASM) is important for the functioning of ecological and societal systems at regional to continental scales, but the long-term evolution and interannual variability of this system is not well understood. Here, we present a stable isotope–based reconstruction of ASM variability covering 4680 BCE to 2011 CE. Superimposed on a gradual drying trend, a rapid drop in mean annual precipitation (>40%) toward persistently drier conditions occurred in ∼1675 BCE. This megadrought caused regional forest deterioration and enhanced aeolian activity affecting Chinese ecosystems. We argue that this abrupt aridification starting ∼2000 BCE triggered wa…
Participant characteristics associated with the effects of a physical and cognitive training program on executive functions
2022
Background: Physical and cognitive interventions have been shown to induce positive effects on older adults’ executive functioning. However, since participants with different background characteristics may respond differently to such interventions, we investigated whether training effects on executive functions were associated with sex, training compliance, and age. We also investigated if change in global cognition was associated with physical and cognitive training intervention-induced changes in executive functions. Methods: Exploratory data from a randomized controlled trial were analyzed. Participants were 70–85-year-old men and women who received a 12-month physical (PT) or physical a…