226 research outputs found
The combinatorics of open covers (II)
We continue to investigate various diagonalization properties for sequences
of open covers of separable metrizable spaces introduced in Part I. These
properties generalize classical ones of Rothberger, Menger, Hurewicz, and
Gerlits-Nagy. In particular, we show that most of the properties introduced in
Part I are indeed distinct. We characterize two of the new properties by
showing that they are equivalent to saying all finite powers have one of the
classical properties above (Hurewicz property in one case and in the Menger
property in other). We consider for each property the smallest cardinality of
metric space which fails to have that property. In each case this cardinal
turns out to equal another well-known cardinal less than the continuum. We also
disprove (in ZFC) a conjecture of Hurewicz which is analogous to the Borel
conjecture. Finally, we answer several questions from Part I concerning
partition properties of covers
Motor (but not auditory) attention affects syntactic choice
Understanding the determinants of syntactic choice in sentence production is a salient topic
in psycholinguistics. Existing evidence suggests that syntactic choice results from an interplay
between linguistic and non-linguistic factors, and a speaker’s attention to the elements
of a described event represents one such factor. Whereas multimodal accounts of attention
suggest a role for different modalities in this process, existing studies examining attention
effects in syntactic choice are primarily based on visual cueing paradigms. Hence, it remains
unclear whether attentional effects on syntactic choice are limited to the visual modality or
are indeed more general. This issue is addressed by the current study. Native English participants
viewed and described line drawings of simple transitive events while their attention
was directed to the location of the agent or the patient of the depicted event by means of
either an auditory (monaural beep) or a motor (unilateral key press) lateral cue. Our results
show an effect of cue location, with participants producing more passive-voice descriptions
in the patient-cued conditions. Crucially, this cue location effect emerged in the motor-cue
but not (or substantially less so) in the auditory-cue condition, as confirmed by a reliable
interaction between cue location (agent vs. patient) and cue type (auditory vs. motor). Our
data suggest that attentional effects on the speaker’s syntactic choices are modality-specific
and limited to the visual and motor, but not the auditory, domain
Static capacitive pressure sensing using a single graphene drum
To realize nanomechanical graphene-based pressure and gas sensors, it is
beneficial to have a method to electrically readout the static displacement of
a suspended graphene membrane. Capacitive readout, typical in
micro-electro-mechanical systems (MEMS), gets increasingly challenging as one
starts shrinking the dimensions of these devices, since the expected
responsivity of such devices is below 0.1 aF/Pa. To overcome the challenges of
detecting small capacitance changes, we design an electrical readout device
fabricated on top of an insulating quartz substrate, maximizing the
contribution of the suspended membrane to the total capacitance of the device.
The capacitance of the drum is further increased by reducing the gap size to
110 nm. Using external pressure load, we demonstrate successful detection of
capacitance changes of a single graphene drum down to 50 aF, and pressure
differences down to 25 mbar
Pesticide exposure: the hormonal function of the female reproductive system disrupted?
Some pesticides may interfere with the female hormonal function, which may lead to negative effects on the reproductive system through disruption of the hormonal balance necessary for proper functioning. Previous studies primarily focused on interference with the estrogen and/or androgen receptor, but the hormonal function may be disrupted in many more ways through pesticide exposure. The aim of this review is to give an overview of the various ways in which pesticides may disrupt the hormonal function of the female reproductive system and in particular the ovarian cycle. Disruption can occur in all stages of hormonal regulation: 1. hormone synthesis; 2. hormone release and storage; 3. hormone transport and clearance; 4. hormone receptor recognition and binding; 5. hormone postreceptor activation; 6. the thyroid function; and 7. the central nervous system. These mechanisms are described for effects of pesticide exposure in vitro and on experimental animals in vivo. For the latter, potential effects of endocrine disrupting pesticides on the female reproductive system, i.e. modulation of hormone concentrations, ovarian cycle irregularities, and impaired fertility, are also reviewed. In epidemiological studies, exposure to pesticides has been associated with menstrual cycle disturbances, reduced fertility, prolonged time-to-pregnancy, spontaneous abortion, stillbirths, and developmental defects, which may or may not be due to disruption of the female hormonal function. Because pesticides comprise a large number of distinct substances with dissimilar structures and diverse toxicity, it is most likely that several of the above-mentioned mechanisms are involved in the pathophysiological pathways explaining the role of pesticide exposure in ovarian cycle disturbances, ultimately leading to fertility problems and other reproductive effects. In future research, information on the ways in which pesticides may disrupt the hormonal function as described in this review, can be used to generate specific hypotheses for studies on the effects of pesticides on the ovarian cycle, both in toxicological and epidemiological settings
Grandiose narcissism associates with higher cognitive performance under stress through more efficient attention distribution: an eye-tracking study
Narcissism is a part of the Dark Triad that consists also of the traits of Machiavellianism and psychopathy. Two main types of narcissism exist: grandiose and vulnerable narcissism. Being a Dark Triad trait, narcissism is typically associated with negative outcomes. However, recent research suggests that at least the grandiose type may be linked (directly or indirectly) to positive outcomes including lower levels of psychopathology, higher school grades in adolescents, deeper and more strategic learning in university students and higher cognitive performance in experimental settings. The current pre-registered, quasi-experimental study implemented eye-tracking to assess whether grandiose narcissism indirectly predicts cognitive performance through wider distribution of attention on the Raven’s Progressive Matrices task. Fifty-four adults completed measures of the Dark Triad, self-esteem and psychopathology. Eight months to one year later, participants completed the Raven’s, while their eye-movements were monitored during high stress conditions. When controlling for previous levels of psychopathology, grandiose narcissism predicted higher Raven’s scores indirectly, through increased variability in the number of fixations across trials. These findings suggest that grandiose narcissism predicts higher cognitive performance, at least in experimental settings, and call for further research to understand the implications of this seemingly dark trait for performance across various settings
Protocol for a systematic review and meta-analysis of human exposure to pesticide residues in honey and other bees' products
Background: The presence of pesticides in honey and related products is an increasing concern for consumers and producers, although there is lack of data on the current burden of exposure of the general human population through these products. We present a protocol for a systematic review and meta-analysis of contamination to insecticides, herbicides and fungicides of products from honeybees, and an estimation of how much the consumption of these products contributes to the ADI (Acceptable Daily Intake) of selected substances. Objectives: We aim to systematically review and meta-analyse studies on the contamination to plant protection products in honey, royal jelly, beeswax and propolis, applying the Navigation Guide and WHO-ILO systematic review methodology as an organizing framework. Data sources: We will search electronic academic databases for potentially relevant records from PubMed, TOXNET and EMBASE. We will include quantitative studies analysing the contamination from insecticides, herbicides and fungicides in honey, propolis, royal jelly and beeswax. In particular, we will evaluate the presence of the following substances and classes of pesticides: Glyphosate, Chlorpyrifos, pyrethroid and neonicotinoid pesticides, fungicides and acaricides. Study appraisal and synthesis methods: At least two authors will independently screen titles and abstracts at a first stage of review, and full texts at a second stage, of potentially eligible records against the eligibility criteria; data extraction of included studies will then be performed by at least two authors, in blind. At least two authors will assess risk of bias and the quality of evidence, using the most suited tools currently available. The data on prevalence of contaminated samples and concentration of pesticides in the products will be combined using meta-analysis: when more than three studies reporting the necessary measures to fit the models are available, meta-analysis will be performed separately by product and by exposure; otherwise, weighted descriptive analysis will be performed. We will report the results using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines (PRISMA)
The European Registered Toxicologist (ERT) : Current status and prospects for advancement
Acknowledgements We would like to thank the participants of the five workshops in which the issues presented in this paper were discussed and the revised guidelines prepared, as well as the EUROTOX Executive Committee and the societies of toxicology of Sweden, the Netherlands, Switzerland, Austria and France for their support which allowed the workshops to take place.Peer reviewedPostprin
HBM4EU chromates study - the measurement of hexavalent and trivalent chromium in exhaled breath condensate samples from occupationally exposed workers across Europe
The aim of this study was to investigate the practicability of exhaled breath condensate (EBC) as a biological matrix to detect and measure hexavalent chromium (Cr(VI)) and trivalent chromium (Cr(III)) in workers occupationally exposed to Cr(VI). EBC samples were collected from workers in France, Finland, Italy, The Netherlands and the United Kingdom from three different target activities: chrome platers, stainless steel welders and surface treatment workers. Pre and post working week EBC samples were collected from 177 exposed workers and 98 unexposed workers (control group). Hyphenated chromatography systems with inductively coupled plasma - mass spectrometry (ICP-MS) were for the analysis. The results showed that the occupationally exposed workers had significantly higher levels of Cr(VI) and Cr(III) than the control group. Chrome platers exhibited the highest Cr(VI) levels in their EBC samples, with a significant increase from their pre to post samples for both Cr(VI) and Cr(III). A significant difference was also found between pre and post EBC samples for Cr(III) in welders. This study has shown that EBC has the potential to be a valid, non-invasive biological matrix to assess occupational exposure to Cr(VI) and Cr(III) for biological monitoring assessment, with the ability to detect low level inhalation exposures.This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 733032 and received co-funding from the author’s organizations and/or Ministries.S
Examining the antecedents of challenge and threat states: The influence of perceived required effort and support availability
To date, limited research has explicitly examined the antecedents of challenge and threat states proposed by the biopsychosocial model. Thus, the aim of the present study was to examine the influence of perceived required effort and support availability on demand/resource evaluations, challenge and threat states, and motor performance. A 2 (required effort; high, low) � 2 (support availability; available, not available) between-subjects design was used with one hundred and twenty participants randomly assigned to one of four experimental conditions. Participants received instructions designed to manipulate perceptions of required effort and support availability before demand/resource evaluations and cardiovascular responses were assessed. Participants then performed the novel motor task (laparoscopic surgery) while performance was recorded. Participants in the low perceived required effort condition evaluated the task as more of a challenge (i.e., resources outweighed demands), exhibited a cardiovascular response more indicative of a challenge state (i.e., higher cardiac output and lower total peripheral resistance), and performed the task better (i.e., quicker completion time) than those in the high perceived required effort condition. However, perceptions of support availability had no significant impact on participants' demand/resource evaluations, cardiovascular responses, or performance. Furthermore, there was no significant interaction effect between perceptions of required effort and support availability. The findings suggest that interventions aimed at promoting a challenge state should include instructions that help individuals perceive that the task is not difficult and requires little physical and mental effort to perform effectively
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