Perovskite crystallization dynamics during spin-casting : an In situ wide-angle x-ray scattering study

In situ wide-angle X-ray scattering (WAXS) has been measured during the spin coating process used to make the precursor films required for the formation of thin films of perovskite. A customized hollow axis spin coater was developed to permit the scattered X-rays to be collected in transmission geometry during the deposition process. Spin coating is the technique most commonly used in laboratories to make thin perovskite films. The dynamics of spin-casting MAPbI3–xClx and FAPbI3–xClx films have been investigated and compared to investigate the differences between the dynamics of MAPbI3–xClx and FAPbI3–xClx film formation. In particular, we focus on the crystallization dynamics of the precursor film formation. When casting MAPbI3–xClx, we observed relatively fast 1D crystallization of the intermediate product MA2PbI3Cl. There was an absence of the desired perovskite phase formed directly; it only appeared after an annealing step that converted the MA2PbI3Cl to MAPbI3. In contrast, slower crystallization via a 3D precursor was observed for FAPbI3–xClx film formation compared to MAPbI3–xClx. Another important finding was that some FAPbI3–xClx perovskite was generated directly during spin-casting before annealing. These findings indicate that there are significant differences between the crystallization pathways for these two perovskite materials. These are likely to explain the differences in the lifetimes of the resulting perovskite solar cell devices produced using FA and MA cations

Epidemiological Features of the Selenium Status in Cattle of Northern California

Selenium (Se) is an essential mineral for animal health. Deficiencies result in white muscle disease (WMD), retained placenta, and ill thrift in cattle. These health problems are known to occur in some northern California herds. This survey was initiated to provide knowledge on the epidemiological features of Se deficiency in cattle in this region. Blood samples were drawn from 10 cows on each of 10 ranches in each of the northern 22 counties. Whole blood Se and glutathione peroxidase (GSH-Px) activities were determined, and these values were statistically compared with each other and with data obtained by questionnaire. The latter included information on animal diseases, soils, forages, and general ranch descriptors like elevation and rainfall. The GSH-Px spot test produced either a positive (+), negative (-) or intermediate (+/-) enzyme activity classification for each cow. Herd classification was identified as + or - if > 70% cow-values fell in that class, otherwise it was identified as +/-. The overall geometric mean blood-Se value was 47.6 ng/ml. Regressions of individual and herd GSH-Px-class against blood-Se values produced r = .75 and r = .82, respectively. Significantly low blood-Se levels were recorded in herds with: 1) negative GSH-Px values, 2) past histories of WMD and ill thrift, 3) predominantly hay diet, 4) pregnant and early lactating cows, and 5) pure bred cows. The Se status of herds using Se-salt blocks was not different from non-supplemented herds. Descriptive ranch variables did not reliably assess the Se status of herds in this study

Epidemiological features of the selenium status in cattle of northern California

Selenium (Se) is an essential mineral for animal health. Deficiencies result in white muscle disease (40), retained placenta, and ill thrift in cattle. These health problems are known to occur in some northern California herds. This survey was initiated to provide knowledge on the epidemiological features of Se deficiency in cattle in this region. Blood samples were drawn from 10 cows on each of 10 ranches in each of the northern 22 counties. Whole blood Se and glutathione peroxidase (GBH-Px) activities were determined, and these values were statistically compared with each other and with data obtained by questionnaire. The latter included information on animal diseases, soils, forages, and general ranch descriptors like elevation and rainfall. The GSH-Px spot test produced either a positive (+), negative (-) or intermediate (+/-) enzyme activity classification for each cow. Herd classification was identified as + or - if >70% cow-values fell in that class, otherwise it was identified as +/-. The overall geometric mean blood-Se value was 47.6 ng/ml. Regressions of individual and herd GSH-Px-class against blood-Se values produced r = .75 and r = .82, respectively. Significantly low blood-Se levels were recorded in herds with: 1) negative GSH-Px values, 2) past histories of WMD and ill thrift, 3) predominantly hay diet, 4) pregnant and early lactating cows, and 5) pure bred cows. The Se status of herds using Se-salt blocks was not different from non- supplemented herds. Descriptive ranch variables did not reliably assess the Se status of herds in this study

Modelling the stroop effect: Dynamics in inhibition of automatic stimuli processing

In this study, we simulate the dynamics of suppressing an automatic stimulus processing which interferes with a different non-automatic target task. The dynamics can be observed in terms of interference and facilitation effects that influence target response processing time. For this purpose, we use Hopfield neural network with varying attention modulation in a colour-word Stroop stimuli processing paradigm. With the biologically realistic features of the network, our model is able to model the Stroop effect in comparison to the human performance

Gossip in organisations: Contexts, consequences and controversies

This article examines the key themes surrounding gossip including its contexts, the various outcomes (positive and negative) of gossip as well as a selection of challenges and controversies. The challenges which are highlighted revolve around definitional issues, methodological approaches, and ethical considerations. Our analysis suggests that the characteristics and features of gossip lend itself to a process-oriented approach whereby the beginning and, particularly, end points of gossip are not always easily identified. Gossip about a subject or person can temporarily disappear only for it to re-surface at some later stage. In addition, questions pertaining to the effects of gossip and ethical-based arguments depend on the nature of the relationships within the gossip triad (gossiper, listener/respondent and target)

Functionally Inert HIV-Specific Cytotoxic T Lymphocytes Do Not Play a Major Role in Chronically Infected Adults and Children

The highly sensitive quantitation of virus-specific CD8+ T cells using major histocompatibility complex–peptide tetramer assays has revealed higher levels of cytotoxic T lymphocytes (CTLs) in acute and chronic virus infections than were recognized previously. However, studies in lymphocytic choriomeningitis virus infection have shown that tetramer assays may include measurement of a substantial number of tetramer-binding cells that are functionally inert. Such phenotypically silent CTLs, which lack cytolytic function and do not produce interferon (IFN)-γ, have been hypothesized to explain the persistence of virus in the face of a quantitatively large immune response, particularly when CD4 help is impaired. In this study, we examined the role of functionally inert CTLs in chronic HIV infection. Subjects studied included children and adults (n = 42) whose viral loads ranged from <50 to >100,000 RNA copies/ml plasma. Tetramer assays were compared with three functional assays: enzyme-linked immunospot (Elispot), intracellular cytokine staining, and precursor frequency (limiting dilution assay [LDA]) cytotoxicity assays. Strong positive associations were observed between cell numbers derived by the Elispot and the tetramer assay (r = 0.90). An even stronger association between tetramer-derived numbers and intracellular cytokine staining for IFN-γ was present (r = 0.97). The majority (median 76%) of tetramer-binding cells were consistently detectable via intracellular IFN-γ cytokine staining. Furthermore, modifications to the LDA, using a low input cell number into each well, enabled LDAs to reach equivalence with the other methods of CTL enumeration. These data together show that functionally inert CTLs do not play a significant role in chronic pediatric or adult HIV infection

The evolution of language: a comparative review

For many years the evolution of language has been seen as a disreputable topic, mired in fanciful &quot;just so stories&quot; about language origins. However, in the last decade a new synthesis of modern linguistics, cognitive neuroscience and neo-Darwinian evolutionary theory has begun to make important contributions to our understanding of the biology and evolution of language. I review some of this recent progress, focusing on the value of the comparative method, which uses data from animal species to draw inferences about language evolution. Discussing speech first, I show how data concerning a wide variety of species, from monkeys to birds, can increase our understanding of the anatomical and neural mechanisms underlying human spoken language, and how bird and whale song provide insights into the ultimate evolutionary function of language. I discuss the ‘‘descended larynx’ ’ of humans, a peculiar adaptation for speech that has received much attention in the past, which despite earlier claims is not uniquely human. Then I will turn to the neural mechanisms underlying spoken language, pointing out the difficulties animals apparently experience in perceiving hierarchical structure in sounds, and stressing the importance of vocal imitation in the evolution of a spoken language. Turning to ultimate function, I suggest that communication among kin (especially between parents and offspring) played a crucial but neglected role in driving language evolution. Finally, I briefly discuss phylogeny, discussing hypotheses that offer plausible routes to human language from a non-linguistic chimp-like ancestor. I conclude that comparative data from living animals will be key to developing a richer, more interdisciplinary understanding of our most distinctively human trait: language

Factors Associated with Revision Surgery after Internal Fixation of Hip Fractures

Background: Femoral neck fractures are associated with high rates of revision surgery after management with internal fixation. Using data from the Fixation using Alternative Implants for the Treatment of Hip fractures (FAITH) trial evaluating methods of internal fixation in patients with femoral neck fractures, we investigated associations between baseline and surgical factors and the need for revision surgery to promote healing, relieve pain, treat infection or improve function over 24 months postsurgery. Additionally, we investigated factors associated with (1) hardware removal and (2) implant exchange from cancellous screws (CS) or sliding hip screw (SHS) to total hip arthroplasty, hemiarthroplasty, or another internal fixation device. Methods: We identified 15 potential factors a priori that may be associated with revision surgery, 7 with hardware removal, and 14 with implant exchange. We used multivariable Cox proportional hazards analyses in our investigation. Results: Factors associated with increased risk of revision surgery included: female sex, [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.25-2.50; P = 0.001], higher body mass index (fo