Search Results (14)

Surge is a typical aerodynamic instability phenomenon in the compressors of aeroengines. The surge can lead to severe performance degradation and even structural damage to the engine and the air vehicle, making it a longstanding critical concern in the industry. Analyzing and understanding the surge process contributes to enhancing the aerodynamic stability of designed compressors. Previous research in this field often focuses solely on the compressor itself while neglecting the mutual interaction between the compressor and other components in the entire engine system. This study investigates the compressor surge process within an integrated engine environment using a full-engine three-dimensional Unsteady Reynolds-averaged Navier–Stokes (URANS) simulation method for the entire engine system, validated through variable geometry turbine experiments on a small turbojet engine. The result demonstrates that the integrated three-dimensional simulation approach can capture the primary flow characteristics of the compression system during surge within an integrated engine environment. Under the influence of the variable geometry turbine, the studied small turbojet engine enters a state of mild surge. This paper also investigates the changes in aerodynamic forces during surge and reveals the two-regime surge phenomenon that exists during the engine surge. Full article

Small stalls and regulated feedings restrict horses’ natural foraging and locomotion, increasing risks to welfare. Environmental enrichment may promote more naturalistic behavioral time budgets, yet little is known about how enrichment type or timing affects physiology and behavior. This study examined nine stabled Quarter Horses provided with hay feeders, activity balls, or mirrors across randomized trials. Each trial included 30 min observations, four times per day, with enrichment removed between sessions and 5-day washouts between trials. Nightwatch^® Smart Halters™ recorded heart and respiration rates, while behaviors were video-scored using instantaneous scan sampling. Observers were not blind to the treatments. Enrichment effects, item type, time of day, and possible interactions for each variable were tested using a GLMM; Tukey’s HSD multiple comparison procedure was used for post hoc comparisons (at p ≤ 0.05). Enrichment significantly increased heart rate compared with the control (p = 0.03), indicating heightened arousal, with hay feeders producing the strongest effects. Respiration rate was unaffected. Mirrors reduced evening heart rates compared with other times (p = 0.02). Across treatments, enrichment increased foraging (p = 0.01) and locomotion (p = 0.03), while reducing frustration behaviors (p = 0.03). Hay feeders produced time budgets most similar to wild horses, suggesting greater effectiveness at meeting behavioral needs. Effects were most pronounced at 12:00 h and 16:00 h, outside routine meals. Overall, enrichment may improve physiological and behavioral outcomes, supporting its role in promoting welfare for stabled horses. Larger studies are needed to assess item-specific and long-term impacts. Full article

Given the suboptimal responses to medication and cognitive behavioral therapies in the treatment of post-traumatic stress disorder (PTSD), new approaches are needed. Background/Objectives: Therapies that include a somatic component such as Emotional Freedom Techniques (EFT) and Eye Movement Desensitization and Reprocessing (EMDR) have demonstrated efficacy in the treatment of PTSD in numerous clinical trials. This case series introduces the Trauma Reintegration Process (TRP), a psychotherapeutic process developed by the author that can be combined with somatic therapies to enhance their effectiveness, especially in patients with dissociation. Methods: This case series describes the use of TRP in combination with EFT, an energy-based somatic treatment that engages the meridian system of the body through gentle tapping on acupressure points. TRP uses EFT in combination with a focused guided imagery sequence. This case series describes the treatment of two patients: a 20-year-old woman who experienced PTSD and somatic symptoms following a serious motor vehicle accident (MVA) and a 45-year-old woman with a history of severe abuse as a child as well as adult trauma who had also been in a serious MVA. The cases contrast the way TRP can be applied in patients with single versus multiple traumas and who experience dissociation. Results: In both cases, EFT treatment stalled when the patient dissociated. After TRP was introduced, however, the EFT treatment regained momentum, leading to significant improvement in PTSD symptoms including a reduction of nightmares and flashbacks and resolution of other somatic symptoms. Conclusions: The trauma reintegration process (TRP) in combination with EFT has the potential to assist in the memory processing of patients with dissociation and complicated trauma presentation without retraumatizing the client and causing further distress or dissociation. In addition, it provides the patient with a self-empowering method to alleviate any additional traumatic sequelae. Full article

Pancreatic cancer is a lethal disease, harboring a five-year overall survival rate of only 13%. Current treatment approaches thus require modulation, with attention shifting towards liberating the stalled efficacy of immunotherapies. Select chemotherapy drugs which possess inherent immune-modifying behaviors could revitalize immune activity against pancreatic tumors and potentiate immunotherapeutic success. In this study, we characterized the influence of gemcitabine, a chemotherapy drug approved for the treatment of pancreatic cancer, on tumor antigen presentation by human leukocyte antigen class I (HLA-I). Gemcitabine increased pancreatic cancer cells’ HLA-I mRNA transcripts, total protein, surface expression, and surface stability. Temperature-dependent assay results indicated that the increased HLA-I stability may be due to reduced binding of low affinity peptides. Mass spectrometry analysis confirmed changes in the HLA-I-presented peptide pool post-treatment, and computational predictions suggested improved affinity and immunogenicity of peptides displayed solely by gemcitabine-treated cells. Most of the gemcitabine-exclusive peptides were derived from unique source proteins, with a notable overrepresentation of translation-related proteins. Gemcitabine also increased expression of select immunoproteasome subunits, providing a plausible mechanism for its modulation of the HLA-I-bound peptidome. Our work supports continued investigation of immunotherapies, including peptide-based vaccines, to be used with gemcitabine as new combination treatment modalities for pancreatic cancer. Full article

The surge is a typical aerodynamic instability phenomenon in the compression system, which can lead to serious consequences such as engine performance degradation and structural damage. A deep understanding of the surge process can support the development of a compressor with a wider operating range. In this paper, an experimental study was carried out and high-responding pressure sensors were used to obtain the aerodynamic instability process and the post-surge characteristics of an axial–centrifugal compressor at design and off-design speeds. The evolution of the flow field and instability behavior before and after the surge were analyzed. The results showed that the inlet temperature change can reflect the aerodynamic instability to some extent, and as the operating condition moves from the choke to surge boundary, the inlet temperature undergoes a sudden increase at a certain condition and further increases with the decrease in mass flow rate. At the design speed, the instability of the combined compressor featured a deep surge with an obvious rotating stall behavior before its inception, and the amplitude of the stall cell was gradually enhanced, finally leading to the surge. At the off-design speed, affected by the stage mismatching, the axial stage mainly worked near the unstable operating condition. Therefore, the compressor successively experiences two modes of mild surge and deep surge, and the rotating stall can also be observed during the surge cycle. Full article

For sows introduced into new groups, the aggressive behavior associated with establishing a social hierarchy represents a period of severe stress. The aim of this study was to investigate the effect of providing sows with an improved pen environment (straw in racks and ropes) on aggressive behavior after mixing and to understand the role played by sow back fat thickness and parity order. At 29 d post-service, sows were mixed into IMPROVED or CONTROL pens with individual feeding stalls (6 groups/treatment, 20 sows/group). Aggressive behavior was recorded for 2 h at mixing (T0) and 24 h (T1) and 3 weeks post-mixing (T21). Overall, the sows in the CONTROL pens performed more fighting behavior compared to the IMPROVED sows (p < 0.001). This difference was significant only at T21 (p < 0.001). Additionally, the sows in the CONTROL pens generally initiated more aggressive behaviors than the sows in the IMPROVED pens (p = 0.02). The sows with a low back fat thickness initiated more aggressive behaviors, but parity had no significant effect on any of the aggressive behaviors. These results indicate a beneficial effect of improvements to the pen environment on the aggression performed by group-housed sows between the time of mixing and three weeks later. The effect was reduced on the day of mixing, which is in accordance with the necessity for sows to employ aggression to establish the dominance hierarchy. Full article

This paper presents in-flight measurements of the interaction of the wing wake of a stalled Slingsby T67 Firefly light aircraft with the aircraft tailplane. Tailplane data was recorded by a GoPro360 camera and analyzed using spatial correlation methods. The tailplane movement and corresponding spectra indicate that the aerodynamic wake shedding frequency closely matches the resonant frequency of the tailplane, resulting in a significant excitation of the structure during heavy stall. Large magnitude, lower frequency tailplane movement was also identified by analysis of the pitch attitude from the image data, with results consistent in post-stall behavior reported by previous modelling and measurements. Full article

The predictions of the onset of rotating stall and surge are very important in the preliminary design stage of a compressor. Rotating stall and surge are complex instabilities that cause efficiency loss and reduced pressure rise, and, therefore, compressor designers attempt to avoid them in the design stage. There are many criteria for predicting stability limits, including empirical, theoretical, and numerical investigations in the literature. However, these investigations have important limitations. The present study establishes a new method in which the stall and post-stall behavior of a compressor is estimated by an equivalent reconstructed compressor using special combinations of single-passage flow behavior in different mass flow rates. The combinations are generated such that pre-stall, in-stall, and surge flow regimes and between one and eight stall cells are reproduced in the full-annulus compressor. The method requires the least computational requirements and is time efficient. The results indicate that secondary flow total energy and spectral entropy are indeed correlated with compressor operating conditions. The predictions of the onset of stall and surge for the investigated compressor show good agreement with the experimental data. Full article

Introduction: The male smoking rate in China declined moderately through the 1990s and early 2000s, but the decline has since stagnated. It is unclear why the decline stalled and whether it stalled uniformly across all social strata. Theories that view socioeconomic status as a fundamental cause of health predict that socioeconomic gaps in smoking may widen, but theories emphasizing the cultural context of health behavior cast doubt on the prediction. We investigated changes in the socioeconomic gaps in smoking during recent decades in China. Methods: We applied growth-curve models to examine inter- and intra-cohort changes in socioeconomic gaps in male smoking in China using data from a national longitudinal survey spanning 25 years. Results: We found diverging trends in smoking in men with different education levels among the post-1980 cohorts; for high-education men, smoking participation consistently declined, but for low-education men, the decline stopped and possibly reversed. The stagnation in the decline in overall smoking rate since 2010 was mostly due to the stalling of the decline of smoking among low-education men in the most recent cohorts. The diverging trends were a continuation of a general trend in expanding educational gaps in smoking that emerged in the cohorts born after 1960. Our analysis also identified widening educational gaps over age within each cohort. Conclusion: We identified a long-term widening in educational gaps in smoking in China. An effective way to reduce smoking, social inequality in smoking and possibly health disparities in China is to target the smoking behavior of vulnerable groups. Full article

The overall unemployment rate in South Africa was impacted by the coronavirus (COVID-19) pandemic, which led many people to resort to informal work such as street trading opportunities in big cities. However, this work is located in the same cities where air pollution is of concern. Furthermore, literature has indicated the lack of regulation of the informal trading sector as compared to the formal sector. An analytical cross-sectional study is proposed to be conducted amongst all of the informal food street vendors (indoor/inside buildings and outdoor/street pavements stalls) in the inner city of Johannesburg, South Africa. By adopting a total sampling method of 746 vendor stalls, this study’s key focus is on inhalation as an occupational exposure. In addition, the study aims to assess the respiratory risk factors amongst informal food street vendors’ stalls and their impact on vendors’ respiratory health. The risk factors to be assessed include the five common air pollutants: street vendor’s infrastructure; socioeconomic factors; personal behavior such as tobacco smoking and handwashing practices; wearing of respiratory protective equipment; and vendors’ exposure duration. The data collection will follow three phases using quantitative methods. In the pre-assessment phase, it will include a pilot study to test the walkthrough survey checklist and the respiratory symptoms and diseases questionnaire. The assessment phase includes a total of eight area samples, which will be taken in a 1-day event over four yearly seasons, as well as thirty personal samples taken in winter over an 8-h work shift. The post-assessment phase will be the development of a risk impact assessment and a risk management model. The study is essential for healthy occupational conditions as indicated in the Occupational Health and Safety (OHS) Act (no. 85 of 1993) and the Regulations governing general hygiene requirements for food premises, the transport of food, and related matters (no. R638 of 22 June 2018). Full article

This prospective and longitudinal study aimed to identify spontaneous post-orchiectomy pain behaviors in horses regardless of the effects of anesthesia, analgesia, and recording time of day. Twenty-four horses divided into four groups were submitted to: inhalation anesthesia only (GA), or combined with previous analgesia (GAA), or orchiectomy under pre (GCA), or postoperative (GC) analgesia. The data obtained from the subtraction of frequency and/or duration of 34 behaviors recorded during seven 60-min time-points in the 24 h after the anesthesia from those recorded in the mirrored time-points in the 24 h before the anesthesia (delta) were compared over time and among groups by Friedman and Kruskal–Wallis tests, respectively (p < 0.05). Time of day influenced the behaviors of walk, look out the window, rest the pelvic limb, and rest standing still. The only pain-related behaviors were decreased mirrored proportional differences in time spent drinking, and eating, and increased mirrored proportional differences in the frequency or duration of look at the wound, retract the pelvic limb, expose the penis, and look at the back of the stall. In conclusion, confounding factors rather than pain may influence several suggestive pain-related behaviors documented in the literature. Full article

Hierarchy formation in domestic sows results in aggression and stress, which might be ameliorated through nutritional satiety. The effect on aggression in group housed, gestating sows provided a standard or high volume of a “standard” diet, or diet enhanced with lignocellulose before, at, and after mixing was studied. Ninety-six Large White cross Landrace weaned sows were allocated to: control diet (CON), high volume diet (HI), and lignocellulose-enhanced diet before and at mixing (LC), and after mixing (LCM) (24 sows per treatment). Sows were housed in stalls for 10 days before mixing, when the CON, HI, and LCM groups were fed a standard diet, and in the LC group, a diet enhanced with lignocellulose at 2.5% was given. At mixing, the CON group continued on a standard diet at 2.5 kg/sow per day, HI were fed the standard diet at 4 kg/sow per day for the first four days and 2.5 kg/sow per day thereafter, and LC and LCM were fed the lignocellulose-enhanced diet at 2.5 kg/sow per day. Behavior, salivary cortisol concentrations, lesion number, and condition were recorded on M0, M1, M6, and M14. Reproduction was assessed using pregnancy rate and progesterone measurements. There were several treatment effects on aggression in the sows following mixing. There were significantly lower fight numbers (CON = 0.34 ± 0.03 Log (1 + x) transformed mean and SEM (1.49 untransformed adjusted mean), LC = 0.31 ± 0.04 (1.14), LCM = 0.42 ± 0.04 (0.28), HI = 0.35 ± 0.04 (1.64); p = 0.001) and longer individual fight durations in the LCM group compared to the CON and LC group (CON = 0.88 s ± 0.07 Log transformed mean and SEM (10.31 s, untransformed adjusted mean), LC = 0.89 ± 0.09 (13.51), LCM = 1.16 ± 0.07 (21.43), HI = 01.03 ± 0.07 (16.42); p = 0.04), and overall higher injury numbers in the LC and LCM groups than the HI. Time spent eating was significantly lower in the CON group than both HI and LC (CON = 7.79 ± 0.37, LC = 8.91 ± 0.38, LCM = 8.49 ± 0.42, HI = 9.55 ± 0.39; p = 0.007). The time spent drinking was also affected by treatment, with more time spent drinking in CON than LC (p = 0.024). The condition score of the sows was affected by diet, with higher condition scores in the HI group than LCM and LC (CON = 2.98 ± 0.11, LC = 2.75 ± 0.10, LCM = 2.74 ± 0.10, HI = 3.12 ± 0.10; p = 0.017). These results suggest that feeding a diet containing 2.5% lignocellulose and a standard diet at a high feeding level for four days post-mixing may affect overall aggression and possibly satiety levels. Our data found decreased fight numbers and increased fight duration in the LCM compared to the LC treatment, and therefore, feeding the fiber source before mixing affects aggression levels differently than when fed just after mixing. A further understanding of different fiber sources and how their physiochemical properties affect digestion and sow satiety would enable critical evaluation and use of fiber sources for benefits in reducing aggression at mixing. Full article

Rotational effects are known to influence severely the aerodynamic performance of the inboard region of rotor blades. The underlying physical mechanisms are however far from being well understood. The present work addresses this problem using Reynolds averaged Navier–Stokes computations and experimental results of the MEXICO (Model Experiments in Controlled Conditions) rotor. Four axisymmetric inflow cases with wind speeds ranging from pre-stall to post-stall conditions are computed and compared with pressure and particle image velocimetry (PIV) experimental data, obtaining, in general, consistent results. At low angles of attack, the aerodynamic behavior of all of the studied blade sections resembles the one from the corresponding 2D airfoils. However, at high angles of attack, rotational effects lead to stall delay and/or lift enhancement at inboard positions. Such effects are shown to occur only in the presence of significant radial flows. Interestingly, the way in which rotational effects influence the aerodynamics of the MEXICO blades differs qualitatively in certain aspects from the descriptions found in the literature about this topic. The presented results provide new insights that are useful for the development of advanced and physically-sound correction models. Full article

Although fisheries production and seafood trade are global in scope, with billions of dollars in exports, the rebuilding of collapsed fisheries often focus on national fisheries policy and management measures, with little attention to global supply chains and international consumer markets. Even with two moratoria and two decades of policy changes since the Northern Gulf cod fisheries collapsed in eastern Canada, rebuilding has stalled and the fishing industry and coastal communities continue to undergo challenges with economic viability and resource sustainability. This paper examines and analyzes the global supply chain and marketing dimension of Northern Gulf cod fisheries. Drawing upon fisheries bioeconomics and governance theory, a pre- and post-collapse analysis is undertaken to understand key drivers and institutional mechanisms along global fish supply chains for an effective and successful rebuilding. Findings indicate that the collapse of the cod fishery has cascading effects that go beyond ecosystem changes to new harvesting activities, industry restructuring, supply chain reorganization, new global markets and consumer preference for certified seafood. This suggests that a holistic rebuilding approach is necessary, one that integrates institutional and behavioral changes for both producers and consumers at various scales of fisheries production, political economy issues, as well as cross-scale policies on marine conservation and regional economic development. Full article