2,166 research outputs found
Analysis of pressure blips in aft-finocyl solid rocket motor
Ballistic anomalies have frequently occurred during the firing of several solid rocket motors (SRMs) (Inertial Upper Stage, Space Shuttle Redesigned SRM (RSRM) and Titan IV SRM Upgrade (SRMU)), producing even relevant and unexpected variations of the SRM pressure trace from its nominal profile. This paper has the purpose to provide a numerical analysis of the following possible causes of ballistic anomalies in SRMs: an inert object discharge, a slag ejection, and an unexpected increase in the propellant burning rate or in the combustion surface. The SRM configuration under investigation is an aft-finocyl SRM with a first-stage/small booster design. The numerical simulations are performed with a quasi-one-dimensional (Q1D) unsteady model of the SRM internal ballistics, properly tailored to model each possible cause of the ballistic anomalies. The results have shown that a classification based on the head-end pressure (HEP) signature, relating each other the HEP shape and the ballistic anomaly cause, can be made. For each cause of ballistic anomalies, a deepened discussion of the parameters driving the HEP signatures is provided, as well as qualitative and quantitative assessments of the resultant pressure signals
On the generality of the effect of experiencing prior gains and losses on the Iowa gambling task: A study on young and old adults
Prospect Theory predicts that people tend to be more risk seeking if their reference point is perceived as a loss and more risk averse when the reference point is perceived as a gain. In line with this prediction, Franken, Georgieva, Muris and Dijksterhuis (2006) showed that young adults who had a prior experience of monetary gains make more safe choices on subsequent decisions than subjects who had an early experience of losses. There are no experimental studies on how experiencing prior gains and losses differently influences young and older adults on a subsequent decision-making task (the Iowa Gambling Task). Hence, in the current paper, adapting the methodology employed by Franken et al.’s (2006), we intended to test the generality of their effect across the life span. Overall, we found that subjects who experienced prior monetary gains or prior monetary losses did not display significant differences in safe/risky choices on subsequent performance in the Iowa Gambling task. Furthermore, the impact of prior gains and losses on risky/safe card selection did not significantly differ between young and older adults. These results showed that the effect found in the Franken et al.’s study (2006) is limited in its generality
The impact of failures and successes on affect and self-esteem in young and older adults
Little is known about the impact of success and failure events on age-related changes in affect states and, particularly, in self-esteem levels. To fill this gap in the literature, in the present study changes in affect and self-esteem in 100 young (19 - 30 years) and 102 older adults (65-81 years) were assessed after participants experienced success and failure in a demanding cognitive task. Overall, the success-failure manipulation induced changes on affect states and on state self-esteem, not on trait self-esteem. Regarding age differences, older and young adults were affected to the same extent by experiences of successes and failures. Theoretical considerations of the empirical findings are provided in the general discussion
I Progetti Pilota della Conferenza Episcopale Italiana.
I Progetti Pilota della Conferenza Episcopale Italiana: il bilancio di una esperienza conclusa sei anni fa con l’ultima edizione del concorso che ha visto la progettazione di tre complessi parrocchiali distribuiti tra Nord, Centro e Sud Italia
Immune-metabolic-inflammatory markers in Holstein cows exposed to a nutritional and environmental stressing challenge
Preliminary results on the influence of laterality in ponies during a two choice palatability test
Protective effects of exosomes derived from lyophilized porcine liver against acetaminophen damage on HepG2 cells
Background: Recently, extracellular vesicles have come to the fore following their emerging role in cell communication, thanks to their ability to reach cells into the human body without dissipating their cargo, transferring biological active molecules, such as proteins, nucleic acids, lipids, etc. They appear as a promising tool in medicine, because of their capability to modulate cellular response in recipient cells. Moreover, a considerable number of publications suggests that exosome uptake is selective but not specific, and it can cross species and cell-type boundaries. This study aims to explore the potential role of porcine liver derived extracellular vesicles, exosomes in particular, to protect human cells from acute damage induced by acetaminophen. Methods: Extracellular vesicles were isolated from porcine lyophilized liver using polymer-based precipitation and a further enrichment was performed using affinity beads. The effects of obtained fractions, total extracellular vesicles and enriched extracellular vesicles, were assessed on human liver derived HepG2 cells. Cell growth and survival were tested, with MTT and area coverage analysis designed by us, as well as protein expression, with immunofluorescence and Western blot. Oxidative stress in live cells was also measured with fluorogenic probes. Results: After proving that porcine extracellular vesicles did not have a toxic effect on HepG2, quite the contrary total extracellular vesicle fraction improved cell growth, we investigated their protective capability with a preconditioning strategy in APAP-induced damage. EVs displayed not only the ability to strongly modulate cell survival responses, but they also were able to boost cell cycle progression. Conclusions: Extracellular vesicles derived from farm animal food derivatives are able to modulate human hepatic cell metabolism, also improving cell survival in a damaged context
Prevalence and time course of post-stroke pain: A multicenter prospective hospital-based study
OBJECTIVE:
Pain prevalence data for patients at various stages after stroke.
DESIGN:
Repeated cross-sectional, observational epidemiological study.
SETTING:
Hospital-based multicenter study.
SUBJECTS:
Four hundred forty-three prospectively enrolled stroke survivors.
METHODS:
All patients underwent bedside clinical examination. The different types of post-stroke pain (central post-stroke pain, musculoskeletal pains, shoulder pain, spasticity-related pain, and headache) were diagnosed with widely accepted criteria during the acute, subacute, and chronic stroke stages. Differences among the three stages were analyzed with χ(2)-tests.
RESULTS:
The mean overall prevalence of pain was 29.56% (14.06% in the acute, 42.73% in the subacute, and 31.90% in the chronic post-stroke stage). Time course differed significantly according to the various pain types (P < 0.001). The prevalence of musculoskeletal and shoulder pain was higher in the subacute and chronic than in the acute stages after stroke; the prevalence of spasticity-related pain peaked in the chronic stage. Conversely, headache manifested in the acute post-stroke stage. The prevalence of central post-stroke pain was higher in the subacute and chronic than in the acute post-stroke stage. Fewer than 25% of the patients with central post-stroke pain received drug treatment.
CONCLUSIONS:
Pain after stroke is more frequent in the subacute and chronic phase than in the acute phase, but it is still largely undertreated
Time-budget of horses reared for meat production: Influence of stocking density on behavioural activities and subsequent welfare
Horses reared for meat production can be kept in intensive breeding farms where they are
housed in group pens at high stocking densities. The present study aimed to evaluate whether the
expressed behaviours correlated with stocking density, and to compare their time-budget with that
of wild-living horses. An ethogram of 13 mutually exclusive behavioural activities was developed.
Behavioural observations were performed over a 72 h period on group pens selected on the basis
of stocking density and the homogeneity of breed, age, height at the withers, and time since
arriving at the farm. Scan sampling (n = 96 scans/horse/day) was used on 22 horses. The mean
frequency (%) standard deviation (SD) for each behavioural activity was calculated to obtain
the time-budget. The associations between time-budget and stocking density were evaluated
using a bivariate analysis. The relationships were analysed by Pearson’s correlation coecient (r).
Our results show that locomotion, playing, and self-grooming positively correlated with a reduction
in stocking density, indicating the potential to use these behaviours as positive welfare indicators for
young horses kept in group pens. The data also revealed an unusual time-budget, where the main
behavioural activity expressed was standing (30.56% 6.56%), followed by feeding (30.55% 3.59%),
lying (27.33% 2.05%), and locomotion (4.07% 1.06%)
Evaluation of macular pigment optical density following femtosecond laser-assisted cataract surgery
Background: To evaluate macular pigment optical density (MPOD) after bimanual femtosecond laser-assisted cataract surgery (FLACS) compared to standard bimanual phacoemulsification (B-MICS). Methods: Aprospective, casematched, comparative cohort study conducted at theInstitute of Ophthalmology, University of Modena and Reggio Emilia (Italy); 30 eyes under wentbimanual FLACS with low-energy Ziemer LDV Z8 (FLACS) and 30 underwent B-MICS standard technique (B-MICS). All interventions were conducted by the same expert surgeon. MPOD using the Macular Pigment Screener II (MPS II) was evaluated at baseline, 7 and 30 days after surgery. As secondary outcomes, we considered best corrected visual acuity (BCVA) and central macular thickness (CMT) obtained using optical coherence tomography. Results: In all cases, a BunnyLens AF IOL was safely implanted in the capsular bag through a1.4 mm incision. We found asignificant reductionin MPOD in both groups at 7 and 30 days; 0.16 ±0.14 and 0.10±0.12 (FLACS) and 0.18±0.13 and 0.15±0.14 (B-MICS), respectively (P<0.05). However, there was no significant difference between the two groups at either 7 (P=0.52) or 30 days (P=0.18). BCVA improved significantly in both groups and CMT increased in both groups (P<0.001, P<0.001, respectively). BCVA and CMT were similar between the groups with a significant difference in CMT in favor of the FLACS group at 30 days (P=0.017). Conclusions: MPOD was reduced in both groups without any significant difference between the FLACS and B-MICS cataract interventions. FLACS is associated with a significantly higher increase of macular thickness at 30 days compared to B-MICS
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