CIT-5: a high-silica zeolite with 14-ring pores

The synthesis and structure of a new zeolite, CIT-5 (California Institute of Technology Number Five), is described, which possesses one-dimensional pores comprised of 14 T-atoms (tetrahedrally coordinated silicon or aluminium atoms)

Crush syndrome

AbstractThe first detailed cases of crush syndrome were described in 1941 in London after victims trapped beneath bombed buildings presented with swollen limbs, hypovolemic shock, dark urine, renal failure, and ultimately perished. The majority of the data and studies on this topic still draw from large databases of earthquake victims. However, in Africa, a continent with little seismic activity, the majority of crush syndrome cases are instead victims of severe beatings rather than earthquake casualties, and clinical suspicion by emergency personnel must be high in this patient group presenting with oliguria or pigmenturia. Damaged skeletal muscle fibres and cell membranes lead to an inflammatory cascade resulting in fluid sequestration in the injured extremity, hypotension, hyperkalemia and hypocalcemia and their complications, and renal injury from multiple sources. Elevations in the serum creatinine, creatine kinase (CK), and potassium levels are frequent findings in these patients, and can help guide critical steps in management. Fluid resuscitation should begin prior to extrication of trapped victims or as early as possible, as this basic intervention has been shown to in large part prevent progression of renal injury to requiring haemodialysis. Alkalinization of the urine and use of mannitol for forced diuresis are recommended therapies under specific circumstances and are supported by studies done in animal models, but have not been shown to change clinical outcomes in human crush victims. In the past 70years the crush syndrome and its management have been studied more thoroughly, however clinical practice guidelines continue to evolve

Resource Use by American Black Bears in Suburbia: A Landholder Step Selection Approach

Range expansion of American black bears (Ursus americanus; bear) and residential development have increased the bear presence in suburbia. Suburban landscapes exhibiting patchworks of variable-sized parcels and habitats and owned by landowners with diverse values can create large areas of suitable habitats with limited public access. These landscapes may limit the effectiveness of hunting as a traditional bear population management tool. Managers require better information regarding landowner attitudes about hunting before implementing harvest regulations intended to mitigate conflicts in suburban areas. To address this need, in 2013, we surveyed landowners to identify properties that allowed bear hunting in 3 suburban areas of Pennsylvania, USA where bear sightings or human–bear conflicts have increased. We then used location data obtained for 29 bears equipped with global positioning system transmitters from 2010 to 2012 to model their resource selection in the study area. We assessed the influence of hunting access, housing density, land cover, and topographic variables on radio-marked black bears monitored 10 days before, during, and after the bear hunting season. We found that resource selection of radio-marked bears was similar for all 3 periods and bears selected for forested land in all 3 seasons and herbaceous cover in the pre-hunting and hunting periods. Resource selection by bears was not influenced by hunting access in the pre-hunting and hunting periods. For the post-hunting period, lands closed to hunting had support as the second-best model. All of the radio-marked bears in our study were vulnerable to harvest. However, they did not change resource selection during the hunting season, nor did they avoid areas open to hunting. Integrating human dimension data with bear habitat use studies, especially in suburban landscapes, has the potential to address bear space use and population management needs often overlooked by traditional research designs

State anxiety and cortisol reactivity to skydiving in novice versus experienced skydivers

Previous studies have suggested that skydiving, a naturalistic stressor, is associated with increases in self-reported stress, anxiety and cortisol levels. However, it has not been established whether this stress reactivity is altered as a function of repeated exposure to skydiving. This is of interest due to previous observations that cortisol reactivity becomes habituated with repeated exposure to laboratory stressors, however, few studies have investigated such habituation to naturalistic stressors. State anxiety and cortisol reactivity to skydiving were measured in 11 first-time skydivers and 13 experienced skydivers (≥ 30 jumps, mean jumps = 397.6), who were to complete a solo skydive. The novice skydivers reported significantly greater levels of state anxiety prior to the jump; however, there were no differences in pre-jump levels of salivary cortisol. Both groups exhibited significantly elevated salivary cortisol levels immediately post-jump, relative to i) pre-jump and ii) recovery. However, the two groups were indistinguishable with regard to their cortisol reactivity to the skydive. These findings support previous research demonstrating that skydiving elicits acute cortisol activation. Further, they suggest that i) cortisol reactivity does not habituate in experienced jumpers, and ii) that there is lack of concordance between self-reported levels of anxiety and biological stress reactivity in experienced skydivers

Strategies from Dramatherapy supervision to augment newly qualified secondary school teachers' experience of self-efficacy and coping strategies in their new role

This study aims to investigate if strategies from Dramatherapy supervision can augment newly qualified teachers’ (NQTs) experience of self-efficacy and coping strategies in their new role. This research study sets out to explore the growing necessity for a more specific form of reflective practice for two separate cohorts of NQTs n =10 (per group) over the course of two consecutive academic years. According to recent research, teacher turnover is more prevalent in disadvantaged urban schools as a result of contextual factors: ‘an increasing workload’, ‘school situation’, the ‘turbulent student-teacher classroom dynamics’, as well as the ‘conflicting agendas between teachers and educational reform’. The study’s theoretical framework draws from teacher education, psychodynamic theory and Dramatherapy supervision theory and practice, to help NQTs develop coping pathways for self-exploration and personal growth, to obtain an increased awareness of the social and emotional processes involved in teaching and learning and to manage both individual and contextual factors that influence their sense of efficacy in their new role as a teacher. The study uses mixed methods to ascertain the efficacy of strategies from Dramatherapy supervision. Quantitative outcome measures are employed to ascertain overall self-efficacy, coping strategies and job satisfaction. Interpretative phenomenological Analyses is used to analyse the qualitative findings amassed from the post-intervention interviews with the NQTs. Autoethnography is employed to bracket the researcher’s personal reflections on the fieldnotes and to study the process of change over time in three case studies, in relation to the NQTs’ sense of efficacy and coping skills. Conclusions drawn from the results highlight that methods from Dramatherapy supervision can be beneficial for developing NQTs’ self-awareness, deepening their understanding of the challenging interpersonal dynamics and providing them with a reflective ‘meditative’ space created through creative techniques. However, the success of these findings is dependent on a number of internal and external variables that influence the NQTs’ sense of efficacy. Recommendations for education include: addressing the impact that the target driven educational climate has on the emotional well-being of teachers and subsequently their pupils, implementing compulsory regular group reflection into teacher practice based on the intervention of ‘strategies from Dramatherapy supervision’ with particular focus on mode 2 of the double matrix model of supervision and embedding training in school communities about and how to be in relationships

Preparation and characterization of zeolite thin films and membranes

A novel technique for the fabrication of zeolite thin films and membranes has been developed. The method utilizes colloidal suspensions of zeolite nanocrystals (nanosols) for deposition of precursor-films. These films can be either supported or self-supported. Following the precursor formation, the films are exposed to a controlled hydrothermal seeded growth (secondary growth) which promotes the formation of thin, continuous, and intergrown zeolite layers at the surface of the precursor-film. Decoupling film deposition from crystal growth provided added flexibility for tailoring film microstructure. This technique has been demonstrated for two distinct structure-types: zeolite L (LTL) and silicalite (MFI). For the case of zeolite L, an asymmetric self-supported film was prepared. The film was composed of a thin (200 nm) and intergrown layer of zeolite L crystals at the film surface. The crystal grain size decreased and interzeolitic porosity increased proceeding from the intergrown surface down into the bulk of the film. However, the films were not continuous enough for molecular sieving membrane applications. For silicalite, a thin (500-1500 nm), intergrown, continuous and oriented silicalite membrane was grown on both supported and self-supported precursor films. The microstructure (i.e., thickness, continuity, orientation) of the films was investigated using electron microscopy and x-ray diffraction. The orientation of the crystals at the surface was found to be such that both straight and sinusoidal channel networks run nearly parallel to the membrane surface. Permeation characteristics of both supported and self-supported silicalite membranes were investigated for several single gas and binary mixtures. Several membranes exhibited ideal selectivities for H\sb2 over N\sb2 as high as 60 at 150\sp\circC and O\sb2 over N\sb2 as high as 3.5 at 185\sp\circC. Both supported and self-supported membranes demonstrated these trends which are attributed to the microstructure of the thin molecular sieving layer

Threading the needle: How humans influence predator–prey spatiotemporal interactions in a multiple-predator system

Perceived predation risk and the resulting antipredator behaviour varies across space, time and predator identity. Communities with multiple predators that interact and differ in their use of space, time of activity and hunting mode create a complex landscape for prey to avoid predation. Anthropogenic presence and disturbance have the potential to shift interactions among predators and prey and the where and when encounters occur. We examined how white-tailed deer Odocoileus virginianus fawn spatiotemporal antipredator behaviour differed along an anthropogenic disturbance gradient that had black bears Ursus americanus, coyotes Canis latrans, bobcats Lynx rufus and humans present. We quantified (a) spatial co-occurrence in species distributions, (b) temporal overlap across the diel cycle and (c) spatiotemporal associations between humans, bears, coyotes, bobcats, adult male deer and fawns. We also examined how deer vigilance behaviour changed across the anthropogenic disturbance gradient and survey duration. Anthropogenic disturbance influenced spatiotemporal co-occurrence across multiple scales, often increasing spatiotemporal overlap among species. In general, species’ spatial co-occurrence was neutral or positive in anthropogenically disturbed environments. Bears and fawns, coyotes and adult male deer, and bobcats and fawns all had higher temporal overlap in the agriculture-development matrix sites. In addition, factors that influenced deer vigilance (e.g. distance to forest edge and predator relative abundance) in the agriculture-development matrix sites did not in the forest matrix site. By taking into account the different antipredator behaviours that can be detected and the different scales these behaviours might occur, we were able to gain a more comprehensive picture of how humans reduce available niche space for wildlife, creating the neutral and positive spatiotemporal associations between species that studies have been seeing in more disturbed areas

Characterization of Zeolite L Nanoclusters

Zeolite L (structure code LTL) crystals are synthesized starting from homogeneous potassium aluminosilicate solutions. Particle size and shape of the formed zeolite L are examined by high-resolution transmission electron microscopy, field emission-scanning electron microscopy, X-ray diffraction, and dynamic light scattering. The synthesis conditions reported lead to nanoclusters of aligned zeolite crystalline domains of dimensions ~40 nm in the channel direction and ~15 nm in the direction perpendicular to the zeolite channels. The nanoclusters have sizes of ~60 nm. Electron microscopy of the nanoclusters reveals the presence of inhomogeneities (intercrystalline porosity) on length scales ranging from 2 to 60 nm. The N_2 and cyclohexane adsorption capacities and the thermal stability of the crystals synthesized are correlated with their microstructure. The preparation of colloidal suspensions of the zeolite L nanoclusters in water is described along with their use in seeded growth and film formation