3,084 research outputs found
Evidence for a Finite Temperature Insulator
In superconductors the zero-resistance current-flow is protected from
dissipation at finite temperatures (T) by virtue of the short-circuit condition
maintained by the electrons that remain in the condensed state. The recently
suggested finite-T insulator and the "superinsulating" phase are different
because any residual mechanism of conduction will eventually become dominant as
the finite-T insulator sets-in. If the residual conduction is small it may be
possible to observe the transition to these intriguing states. We show that the
conductivity of the high magnetic-field insulator terminating superconductivity
in amorphous indium-oxide exhibits an abrupt drop, and seem to approach a zero
conductance at T<0.04 K. We discuss our results in the light of theories that
lead to a finite-T insulator
Modeling truncated pixel values of faint reflections in MicroED images.
The weak pixel counts surrounding the Bragg spots in a diffraction image are important for establishing a model of the background underneath the peak and estimating the reliability of the integrated intensities. Under certain circumstances, particularly with equipment not optimized for low-intensity measurements, these pixel values may be corrupted by corrections applied to the raw image. This can lead to truncation of low pixel counts, resulting in anomalies in the integrated Bragg intensities, such as systematically higher signal-to-noise ratios. A correction for this effect can be approximated by a three-parameter lognormal distribution fitted to the weakly positive-valued pixels at similar scattering angles. The procedure is validated by the improved refinement of an atomic model against structure factor amplitudes derived from corrected micro-electron diffraction (MicroED) images
CaracterĂsticas de los ejercicios de prácticas de laboratorio incluidos en los libros de textos de Ciencias utilizados en Cataluña
The laboratory exercices in science textbooks used in grades 9 to 12 in Catalonian schools were content analyzed by three instruments: The Inquiry Leve1 Index (ILI), the Laboratory Assessment Inventory (LAI) and the Laboratory Dimenssions Inventory (LDI). The analysis was carried out by 24 teachers under the guidance of two science educators as an assignment in an in-service course on teaching and evaluation in the laboratory. It was found that the number of laboratory exercises offered in Catalonian science texbooks is rather small compared with texbooks in countries such as the U. K. and U.S.A. Most of the exercises are of low inquiry level featuring manipulation but missing high other inquiry skills such as formulating questions and hypotheses, designing experiments, etc. The relationship between practical work and theory is hardly indicated and the potential of the laboratory as a means to enhancing concept learning andlor developing social skills are hardly being considered. There is an urgent need to reform laboratory work in Catalonian schools
Emotion Goals: What do Sexual Offenders Want to Feel?
Sexual offenders typically experience more negative emotions and greater difficulties in regulating emotions than non-offenders. However, limited data exist on what sexual offenders want to feel (i.e., their emotion goals). Notably, emotion goals play a key role in emotion regulation and contribute to emotional experience. The present study tested whether sexual offenders (N = 31) reported higher scores for negative emotion goals and lower scores for positive emotion goals, compared with general offenders (N = 26) and non-offenders (N = 26). In addition, we tested whether sexual offenders differed from the other two groups in their perceived pleasantness and perceived utility of emotions. Sexual offenders reported greater scores for the emotion goal of sadness, and lower scores for the emotion goal of excitement, compared with both general offenders and non-offenders. State and trait levels of these emotions could not fully account for these differences. Furthermore, sexual offenders reported lower perceived pleasantness for sadness than general offenders and lower perceived pleasantness for excitement compared with both other groups. Finally, sexual offenders reported greater perceived utility of sadness than non-offenders. These novel findings and their implications for research and interventions are discussed in the context of sexual offenders' emotional dysfunction
The MRI finding of the nerve root sedimentation sign: Its clinical validity and operative relativity for patients with lumbar spinal stenosis
AbstractBackgroundLumbar spinal stenosis (LSS) is increasingly being recognised as a cause of disabling low back and lower extremities pain in adult population. Advanced spinal imaging thought as confirmation tool for the diagnosis and as preoperative tool to delineate the extent and precise location of the pathology. Nerve roots normally sediment, due to gravity, to the dorsal part of the dural sac, which was known as negative sedimentation sign. If there is MRI finding of nerve roots in the ventral part of the dural sac the sedimentation sign is positive.ObjectivesTo evaluate the presence of the MRI finding of positive sedimentation sign in patients clinically suspected to have lumbar spinal stenosis and to follow up operated cases to identify the absence of the radiological signs in the operated cases.Material and methods70 patients clinically suspected to have lumbar spinal stenosis evaluated by MRI lumbosacral spine in supine position. A panel of two radiologists reviewed radiological data. MRI features were agreed by both radiologists in 48 patients. Out of these 48 patients; 25 were operated upon for central decompressive laminectomy, partial medial facetectomy and foraminotomy with instrumented fusion and fixation if indicated. Visual analogue score (VAS) collectively preoperative and postoperative was compared and the walking distance postoperative was reported and follow up MRI studies were done one year after the operation.ResultsOperated patients’ mean age was 58.2years; nineteen patients were operated upon for simple decompressive laminectomy for the affected levels. Walking distance preoperative range 100–700metres, improved postoperative to be 1474.0±601.1. VAS for pain preoperative was 9.28±0.84, improved at 12month follow up to be 0.84±0.62. Postoperative MRI done to evaluate the cross sectional area (CSA) became more than 80mm2 in the absence of the sedimentation sign and was negative in 22 cases.ConclusionThe MRI finding of positive sedimentation sign is a good positive sign to rule in lumbar spinal stenosis with high specificity and sensitivity; negative sedimentation sign can be used in postoperative follow up of decompression patients
MicroED data collection and processing.
MicroED, a method at the intersection of X-ray crystallography and electron cryo-microscopy, has rapidly progressed by exploiting advances in both fields and has already been successfully employed to determine the atomic structures of several proteins from sub-micron-sized, three-dimensional crystals. A major limiting factor in X-ray crystallography is the requirement for large and well ordered crystals. By permitting electron diffraction patterns to be collected from much smaller crystals, or even single well ordered domains of large crystals composed of several small mosaic blocks, MicroED has the potential to overcome the limiting size requirement and enable structural studies on difficult-to-crystallize samples. This communication details the steps for sample preparation, data collection and reduction necessary to obtain refined, high-resolution, three-dimensional models by MicroED, and presents some of its unique challenges
Mask exposure during COVID-19 changes emotional face processing
Faces are one of the key ways that we obtain social information about others. They allow people to identify individuals, understand conversational cues, and make judgements about others’ mental states. When the COVID-19 pandemic hit the United States, widespread mask-wearing practices were implemented, causing a shift in the way Americans typically interact. This introduction of masks into social exchanges posed a potential challenge—how would people make these important inferences about others when a large source of information was no longer available? We conducted two studies that investigated the impact of mask exposure on emotion perception. In particular, we measured how participants used facial landmarks (visual cues) and the expressed valence and arousal (affective cues), to make similarity judgements about pairs of emotion faces. Study 1 found that in August 2020, participants with higher levels of mask exposure used cues from the eyes to a greater extent when judging emotion similarity than participants with less mask exposure. Study 2 measured participants’ emotion perception in both April and September 2020 –before and after widespread mask adoption—in the same group of participants to examine changes in the use of facial cues over time. Results revealed an overall increase in the use of visual cues from April to September. Further, as mask exposure increased, people with the most social interaction showed the largest increase in the use of visual facial cues. These results provide evidence that a shift has occurred in how people process faces such that the more people are interacting with others that are wearing masks, the more they have learned to focus on visual cues from the eye area of the face
Genetic analysis of milk yield in first-lactation Holstein-Friesian in Ethiopia: A lactation average vs random regression test-day model analysis
201
Feeding live prey to zoo animals: response of zoo visitors in Switzerland
In summer 2007, with the help of a written questionnaire, the attitudes of more than 400 visitors to the zoological garden of Zurich, Switzerland, toward the idea of feeding live insects to lizards, live fish to otters, and live rabbits to tigers were investigated. The majority of Swiss zoo visitors agreed with the idea of feeding live prey (invertebrates and vertebrates) to zoo animals, both off- and on-exhibit, except in the case of feeding live rabbits to tigers on-exhibit. Women and frequent visitors of the zoo disagreed more often with the on-exhibit feeding of live rabbits to tigers. Study participants with a higher level of education were more likely to agree with the idea of feeding live invertebrates and vertebrates to zoo animals
off-exhibit. In comparison to an earlier study undertaken in Scotland, zoo visitors in Switzerland were more often in favor of the live feeding of vertebrates. Feeding live prey can counter the loss of hunting skills of carnivores and improve the animals’ well-being. However, feeding enrichments have to strike a balance between optimal living conditions of animals and the quality of visitor experience.
Our results show that such a balance can be found, especially when live feeding of mammals is carried out off-exhibit. A good interpretation of food enrichment might help zoos to win more support for the issue, and for re-introduction programs and conservation
- …