1,459 research outputs found

    Meet the fribbles: Novel stimuli for use within behavioural research

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    Clinical researchers make use of experimental models for mental disorders. In many cases, these models use stimuli that are relevant to the disorder under scrutiny, which allows one to experimentally investigate the factors that contribute to the development of the disorder. For example, one might use spiders or spider-like stimuli in the study of specific phobia. More broadly, researchers often make use of real-world stimuli such as images of animals, geometrical shapes or emotional words. However, these stimuli are often limited in their experimental controllability and their applicability to the disorder in question. We present a novel set of animal-like stimuli, called Fribbles, for use within behavioural research. Fribbles have desirable properties for use in research because they are similar to real-world stimuli, but due to their novelty, participants will not have had previous experience with them. They also have known properties that can be experimentally manipulated. We present an investigation into similarity between Fribbles in order to illustrate their utility in research that relies on comparisons between similar stimuli. Fribbles offer both experimental control and generalisability to the real world, although some consideration must be made concerning the properties that influence similarity between Fribbles when selecting them along a dimension of similarity. © 2014 Barry, Griffith, De Rossi and Hermans.published_or_final_versio

    What is the numerical nature of pain relief?

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    Pain relief, or a decrease in self-reported pain intensity, is frequently the primary outcome of pain 10 clinical trials. Investigators commonly report pain relief in one of two ways: using raw units (additive) 11 or using percentage units (multiplicative). However, additive and multiplicative scales have different 12 assumptions and are incompatible with one-another. In this work, we describe the assumptions and 13 corollaries of additive and multiplicative models of pain relief to illuminate the issue from statistical 14 and clinical perspectives. First, we explain the math underlying each model and illustrate these points 15 using simulations, for which readers are assumed to have an understanding of linear regression. Next, we 16 connect this math to clinical interpretations, stressing the importance of statistical models that accurately 17 represent the underlying data; for example, how using percent pain relief can mislead clinicians if the data are actually additive. These theoretical discussions are supported by empirical data from four 19 longitudinal studies of patients with subacute and chronic pain. Finally, we discuss self-reported pain 20 intensity as a measurement construct, including its philosophical limitations and how clinical pain differs 21 from acute pain measured during psychophysics experiments. This work has broad implications for 22 clinical pain research, ranging from statistical modeling of trial data to the use of minimal clinically important differences and patient-clinician communication

    Empirical constraints on the nucleosynthesis of nitrogen

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    We derive empirical constraints on the nucleosynthetic yields of nitrogen by incorporating N enrichment into our previously developed and empirically tuned multizone galactic chemical evolution model. We adopt a metallicity-independent (‘primary’) N yield from massive stars and a metallicity-dependent (‘secondary’) N yield from AGB stars. In our model, galactic radial zones do not evolve along the observed [N/O]–[O/H] relation, but first increase in [O/H] at roughly constant [N/O], then move upward in [N/O] via secondary N production. By t ≈ 5 Gyr, the model approaches an equilibrium [N/O]–[O/H] relation, which traces the radial oxygen gradient. Reproducing the [N/O]–[O/H] trend observed in extragalactic systems constrains the ratio of IMF-averaged N yields to the IMF-averaged O yield of core-collapse supernovae. We find good agreement if we adopt |yNCC/yOCC=0.024y_\text{N}^\text{CC}/y_\text{O}^\text{CC}=0.024| and |yNAGB/yOCC=0.062(Z/Z)y_\text{N}^\text{AGB}/y_\text{O}^\text{CC} = 0.062(Z/Z_\odot)|⁠. For the theoretical AGB yields we consider, simple stellar populations release half their N after only ∼250 Myr. Our model reproduces the [N/O]–[O/H] relation found for Milky Way stars in the APOGEE survey, and it reproduces (though imperfectly) the trends of stellar [N/O] with age and [O/Fe]. The metallicity-dependent yield plays the dominant role in shaping the gas-phase [N/O]–[O/H] relation, but the AGB time-delay is required to match the stellar age and [O/Fe] trends. If we add ∼40 per cent oscillations to the star formation rate, the model reproduces the scatter in the gas phase [N/O]–[O/H] relation observed in external galaxies by MaNGA. We discuss implications of our results for theoretical models of N production by massive stars and AGB stars

    Slatted pen floors reduce Salmonella in market swine held in abattoirs

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    The objective of this study was to directly compare Salmonella isolation rates from pig slaughtered after 4 hours holding on slatted or solid concrete floors. Seven truckloads (replicates) of market swine ( 120 kg) from a fully integrated farrow-to-slaughter operation were studied. At unloading, groups of pigs (15-30) were sorted to 1) no-hold (20-45 minutes waiting), 2) pens with solid concrete floors (4 hours), 3) slatted concrete floors (4 hours). Postmortem samples were cultured for Salmonella. Those pigs held in pens with slatted floors (63.6%) had significantly (P \u3c 0.05) less Salmonella in their ceca than those held on solid floors (72.7%)

    Parameters for successful nonoperative management of traumatic aortic injury

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    ObjectiveBlunt traumatic aortic injury is associated with significant mortality, and increased computed tomography use identifies injuries not previously detected. This study sought to define parameters identifying patients who can benefit from medical management.MethodsWe reviewed 4.5 years of blunt traumatic aortic injuries. Injury was classified as grade I (intimal flap or intramural hematoma), II (small pseudoaneurysm <50% circumference), III (large pseudoaneurysm >50% circumference), and IV (rupture/transection). Secondary signs of injury included pseudocoarctation, extensive mediastinal hematoma, and large left hemothorax. Follow-up, including computed tomography, was reviewed.ResultsWe identified 97 patients: 31 grade I, 35 grade II, 24 grade III, and 7 grade IV; 67(69%) male; mean age 47 ± 18.8 years, mean Injury Severity Score 38.8 ± 14.6; overall survival 76 (78.4%). Secondary signs of injury were found in 30 patients. Overall, 52 (53.6%) underwent repair, 45 undergoing thoracic endovascular aortic repair, with 2 (2.22%) procedure-related deaths, and 7 undergoing open repair. Five patients undergoing thoracic endovascular aortic repair required 7 additional procedures. In 45 medically managed patients, there were 14 deaths (31%), all secondary to associated injuries. Injury Severity Scores of survivors and nonsurvivors were 33 ± 10.8 and 48.6 ± 12.8, respectively (P < .001). Follow-up showed resolution or no change in 21 (91%) and a small increase in 2 grade I injuries.ConclusionsAll blunt traumatic aortic injury does not necessitate repair. Stratification by injury grade and secondary signs of injury identifies patients appropriate for medical management. Grade IV injury necessitates emergency procedures and carries high mortality. Grade III injury with secondary signs of injury should be urgently repaired; patients without secondary signs of injury may undergo delayed repair. Grade I and II injuries are amenable to medical management

    Emissions from Smoldering Combustion of Biomass Measured by Open-Path Fourier Transform Infrared Spectroscopy

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    Biomass samples from a diverse range of ecosystems were burned in the Intermountain Fire Sciences Laboratory open combustion facility. Midinfrared spectra of the nascent emissions were acquired at several heights above the fires with a Fourier transform infrared spectrometer (FTIR) coupled to an open multipass cell. In this report, the results from smoldering combustion during 24 fires are presented including production of carbon dioxide, carbon monoxide, methane, ethene, ethyne, propene, formaldehyde, 2-hydroxyethanal, methanol, phenol, acetic acid, formic acid, ammonia, hydrogen cyanide, and carbonyl sulfide. These were the dominant products observed, and many have significant influence on atmospheric chemistry at the local, regional, and global scale. Included in these results are the first optical, in situ measurements of smoke composition from fires in grasses, hardwoods, and organic soils. About one half of the detected organic emissions arose from fuel pyrolysis which produces white smoke rich in oxygenated organic compounds. These compounds deserve more attention in the assessment of fire impacts on the atmosphere. The compound 2-hydroxyethanal is a significant component of the smoke, and it is reported here for the first time as a product of fires. Most of the observed alkane and ammonia production accompanied visible glowing combustion. NH3 is normally the major nitrogen-containing emission detected from smoldering combustion of biomass, but from some smoldering organic soils, HCN was dominant. Tar condensed on cool surfaces below the fires accounting for ∼1% of the biomass burned, but it was enriched in N by a factor of 6–7 over the parent material, and its possible role in postfire nutrient cycling should be further investigated

    Nucleosynthesis signatures of neutrino-driven winds from proto-neutron stars: a perspective from chemical evolution models

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    We test the hypothesis that the observed first-peak (Sr, Y, Zr) and second-peak (Ba) s-process elemental abundances in low-metallicity Milky Way stars, and the abundances of the elements Mo and Ru, can be explained by a pervasive r-process contribution originating in neutrino-driven winds from highly-magnetic and rapidly rotating proto-neutron stars (proto-NSs). We construct chemical evolution models that incorporate recent calculations of proto-NS yields in addition to contributions from AGB stars, Type Ia supernovae, and two alternative sets of yields for massive star winds and core-collapse supernovae. For non-rotating massive star yields from either set, models without proto-NS winds underpredict the observed s-process peak abundances by 0.30.3-1dex1\,\text{dex} at low metallicity, and they severely underpredict Mo and Ru at all metallicities. Models incorporating wind yields from proto-NSs with spin periods P2P \sim 2-5ms5\,\text{ms} fit the observed trends for all these elements well. Alternatively, models omitting proto-NS winds but adopting yields of rapidly rotating massive stars, with vrotv_{\rm rot} between 150150 and 300kms1300\,\text{km}\,\text{s}^{-1}, can explain the observed abundance levels reasonably well for [Fe/H]<2\text{[Fe/H]}<-2. These models overpredict [Sr/Fe] and [Mo/Fe] at higher metallicities, but with a tuned dependence of vrotv_{\rm rot} on stellar metallicity they might achieve an acceptable fit at all [Fe/H]. If many proto-NSs are born with strong magnetic fields and short spin periods, then their neutrino-driven winds provide a natural source for Sr, Y, Zr, Mo, Ru, and Ba in low-metallicity stellar populations. Conversely, spherical winds from unmagnetized proto-NSs overproduce the observed Sr, Y, and Zr abundances by a large factor.Comment: Accepted for publication in MNRA

    A multimerizing transcription factor of sea urchin embryos capable of looping DNA

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    SpGCF1 is a recently cloned sea urchin transcription factor that recognizes target sites in several different sea urchin genes. We find that in gel-shift experiments this factor is able to multimerize. A quantitative simulation of the gel-shift results suggests that SpGCF1 molecules that are bound to DNA target sites may also bind to one another, thus associating several DNA probe molecules. SpGCF1 might therefore be able to loop DNA molecules bearing its target sites at distant locations. We demonstrate this prediction by electron microscopy, and using the well-characterized cis-regulatory domain of the CyIIIa cytoskeletal actin gene, we show that the loop conformations predicted from the known SpGCF1 target site locations are actually formed in vitro. We speculate that the multimerization of this factor in vivo may function to bring distant regions of extended regulatory domains into immediate proximity so that they can interact with one another

    Peracute Infection of Swine With Salmonella

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    It has recently been experimentally demonstrated that pigs exposed naturally to Salmonella on the floor of abattoir holding pens can become infected between two and six hours after being placed in the pens. In addition we have demonstrated that tonsillar tissue are almost immediately culture positive following such exposure under experimental conditions. The objective of this study was to determine the shortest amount of time necessary for infection of selected tissues and to determine if the tonsil served as a route for Salmonella entry into lymphoid tissues draining the tonsil. Forty-four Salmonella-negative, market age pigs (90 to 110 kg) were fasted overnight and exposed to approximately 2 X 106 Salmonella enterica serotype Typhimurium strain X4232 (nalidixic acid resistant). The bacteria were mixed with a fecal slurry and the slurry spread on the floor of the pens. Pigs were euthanized at 15, 30, 45, 60 and 120 minutes following initial exposure. Tonsil of the soft palate, medial retropharyngeal lymph node, ileocecal lymph node, a five centimeter section of the terminal ileum, cecal contents and 100 ml of blood were cultured for Salmonella. Strain X4232 was isolated from 98 % (43/44) of tonsils. Strain X4232 was isolated from the ileocecal lymph node within 45 minutes (2/9 pigs), terminal ileum within 15 minutes (1/9 pigs), cecal contents within 15 minutes (1/9 pigs), and blood within 45 minutes (1/9 pigs). Strain X4232 was not recovered from the medial retropharyngeal lymph node, indicating that the organism did not move rapidly into this node from the tonsil of the soft palate. Results of this study indicate that Salmonella can be recovered from selected tissues in market age swine in less than the normal two hour abattoir holding time

    The effects of nonsuicidal self-injury on parenting behaviors: A longitudinal analyses of the perspective of the parent

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    Background: The present study is the first to examine predictors and consequences of nonsuicidal self-injury (NSSI) in adolescence using parent-reported data in a longitudinal design. Across three time points, we examined the reciprocal effects of parent-reported parenting behaviors as they are related to adolescents' NSSI. Methods: The present study is a three-wave prospective study in a large sample of community adolescents and their parents. At time 1 (age 12), the sample consisted of 1396 adolescent reports and 1438 parent reports. Time 2 (age 13) included 827 adolescent and 936 parent reports. At time 3 (age 14), 754 adolescent and 790 parent reports were obtained. Engagement in NSSI (adolescent report) was determined by an affirmative response to the item 'Have you intentionally injured yourself (e.g., cut, burn, scratch) this year, without the intent to die?'. Parental awareness of NSSI at age 13 and 14 was examined using a single-item screening question. Parenting behaviors were examined by the parent versions of the Parental Behavior Scale. Results: Results showed that although NSSI was reported by 10 % of the adolescents, only 3 % of the parents were aware of the NSSI behaviors of their children. Cross-lagged analyses showed a reciprocal relationship between NSSI and parenting behaviors over time. We found a significant effect of both positive parenting and controlling parenting on the presence of NSSI at time 2. But vice versa NSSI also has an effect on parenting behaviors over time. Results showed that NSSI at time 1 has an impact on controlling parenting behaviors, namely punishment at time 2. NSSI at time 2 showed an impact on parent's perception of positive parenting, parental rule setting, punishment and harsh punishment. Conclusions: The present study examined predictors and consequences of NSSI in a longitudinal design, and emphasized the importance of examining reciprocal interactions between NSSI and parenting behaviors. Furthermore, it is the first study to examine parent-reported data in a longitudinal design and gives insight into parents' perspectives
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