Träningsintensitet hos islandshästar i ridskoleverksamhet

Exercise intensity of Icelandic riding school horses In Sweden, there are a total of 9500 horses at riding schools and a hundred riding schools with Icelandic horses. These horses are performing 5 million hours under rider each year. Despite this, there are very few studies measuring training intensity of horses in riding schools. Riding school horses are commonly participating in competitions during the year. However, there are no present studies on Icelandic horses training intensity at riding schools. The main goal for training is to improve fitness and capacity of the horse to sustain a long and healthy life. To reduce the risk of overtraining, that results in damage to musculoskeletal tissues and potentially cause of lameness, trainers and riders must be aware of tools that can provide a better training schedule for the horse. Heart rate monitors are easy to use and provide a good tool for an objective measuring of condition. In this study training intensity of the Icelandic horse is measured in a riding school environment. The study contains two purposes; To find out how low/high the training intensity is and to see if the horses are well prepared for the type of competition they are competing in. The hypothesis was that the horses would not reach a high intensity during training, meaning they will rarely reach a heart rate frequency over 200 beats per minute and lactate levels around and above 4mmol/ L. The horses will reach a higher heart rate frequency during the competition than during training. Five horses were measured during two weeks, totally at 8 occasions. The horse’s heart rate was measured before, during and after training. Lactate was measured by blood samples at the first occasion, immediately after the highest intensity of the training. Four horses were used to measure the heart rate under a training occasion in comparison to a competition situation. The results of the measurements showed that the horses had a heart rate over 175 beat per minute during 02.18 minutes per training occasion and 03.43 minutes during the competition occasion. The horses had a low training intensity both during training and competition. Ten minutes after the competition the horse’s heartrate had recovered to below 80 beats per minute. They were prepared for the type of competition they were participating in.I Sverige finns det totalt 9500 hästar på ridskolor runt om i landet (Svensk Ridsport 2017) och ett 100-tal ridskolor med islandshästar (Svenska Islandshäst Förbundet 2017). Dessa hästar utför 5 miljoner ridtimmar på ridskola varje år. Trots det höga antalet ridtimmar finns det endast ett fåtal studier utförda på hästarnas träningsintensitet i ridskoleverksamhet. Det är även vanligt att ridskolehästar deltar i tävlingssammanhang under terminerna vilket ställer ytterligare krav på deras fysiska förmågor. Enligt Evans (2000) kan ryttare, med hjälp av hjärtfrekvensmätningar, designa ett individanpassat träningsprogram för varje häst. Hjärtfrekvensmätare hjälper ryttaren kontrollera att hästen får den återhämtning den behöver, samtidigt som den tränar tillräckligt hårt för att förbättra sin kondition. Utan att mäta hjärtfrekvens eller laktatnivå vid träning vet ryttaren aldrig hur mycket hästen anstränger sig. Det är då inte möjligt att kontrollera träningsintensiteten efter de mål som är önskat för hästen. Hastighet och sträcka har även det en betydelse i förhållande till hjärtfrekvensen. Ryttaren behöver veta vilken hastighet och under hur lång sträcka hästen ska arbeta i en viss hjärtfrekvens för att kunna nå resultat med träningen och bygga upp en frisk och hållbar häst. Med hjälp av att kontrollera hästens återhämtning kan ryttaren upptäcka tidiga tecken på om något är fel i hästens kropp. En obalans mellan träning och återhämtning bidrar till en överansträngd häst och resultatet kan då bli t.ex. hälta, viktminskning, brist på tävlingsinstinkt och försämrad prestation (Hyyppä & Pösö 2004). En för låg träningsintensitet kan bidra till att hästen inte når sin önskade kapacitet. Hjärtfrekvens kan mätas med stetoskop eller genom att känna efter hästens hjärtfrekvens t.ex. under käken (Davies 2005). Hjärtfrekvensmätning i form av hjärtfrekvensband och hjärtfrekvensklocka ger möjlighet att mäta hjärtfrekvensen under hela ridpasset inklusive uppvärmning och nedvarvning. De moderna hjärtfrekvensklockorna har även en GPS funktion som mäter distansen på träningspasset samt vilket tempo hästen tränar i. Genom att kunna kontrollera vid vilken hastighet och distans hästen har en viss hjärtfrekvens, kan ryttaren anpassa intensiteten på träningen för att hästen ska hålla sig frisk och prestera efter sin bästa förmåga. Detta är ofta okända parametrar för många ryttare

Large-eddy simulation of a two-layer boundary-layer cloud system from the Arctic Ocean 2018 expedition

Climate change is particularly noticeable in the Arctic. The most common type of cloud at these latitudes is mixed-phase stratocumulus. These clouds occur frequently and persistently during all seasons and play a critical role in the Arctic energy budget. Previous observations in the central (north of 80&deg; N) Arctic have shown a high occurrence of prolonged periods of a shallow, single-layer mixed-phase stratocumulus at the top of the boundary layer (BL; altitudes ~300 to 400 m). However, recent observations from the summer of 2018 instead showed a prevalence of a two-layer boundary-layer cloud system. Here we use large-eddy simulation to examine the maintenance of one of the cloud systems observed in the summer of 2018 as well as the sensitivity of the cloud layers to different micro- and macro-scale parameters. We find that the model generally reproduces the observed thermodynamic structure well, with two near-neutrally stratified layers in the BL caused by a low cloud (located within the first few hundred meters) capped by a lower temperature inversion, and an upper cloud layer (based around one km or slightly higher) capped by the main temperature inversion of the BL. The investigated cloud structure is persistent unless there are low aerosol number concentrations (&le; 5 cm-3), which cause the upper cloud layer to dissipate, or high large-scale wind speeds (greater than or equal 8.5 m s-1), which erode the lower inversion and the related cloud layer. These types of changes in cloud structure lead to a substantial reduction of the net longwave radiation at the surface due to a lower emissivity or higher altitude of the remaining cloud layer. The findings highlight the importance of better understanding and representing aerosol sources and sinks over the central Arctic Ocean. Furthermore, they underline the significance of meteorological parameters, such as the large-scale wind speed, for maintaining the two-layer boundary-layer cloud structure encountered in the lower atmosphere of the central Arctic.</p

Aerosol number-size distributions during clear and fog periods in the summer high Arctic: 1991, 1996 and 2001

The present study covers submicrometer aerosol size distribution data taken during three Arctic icebreaker expeditions in the summers of 1991, 1996 and 2001. The size distributions of all expeditions were compared in log-normally fitted form to the statistics of the marine number size distribution provided by Heintzenberg et al. (2004) yielding rather similar log-normal parameters of the modes. Statistics of the modal concentrations revealed strong concentration decreases of large accumulation mode particles with increasing length of time spent over the pack ice. The travel-time dependencies of both Aitken and ultrafine modes strongly indicate, as other studies did before, the occurrence of fine-particle sources in the inner Arctic. With two approaches evidence of fog-related aerosol source processeswas sought for in the data sets of 1996 and 2001 because they included fog drop size distributions. With increasing fog intensity modes in interstitial particle number concentrations appeared in particular in the size range around 80 nm that was nearly mode free in clear air. A second, dynamic approach revealed that Aitken mode concentrations increased strongly above their respective fog-period medians in both years before maximum drop numbers were reached in both years. We interpret the results of both approaches as strong indications of fog-related aerosol source processes as discussed in Leck and Bigg (1999) that need to be elucidated with further data from dedicated fog experiments in future Arctic expeditions in order to understand the life cycle of the aerosol over the high Arctic pack ice area

A transitioning Arctic surface energy budget: the impacts of solar zenith angle, surface albedo and cloud radiative forcing

Snow surface and sea-ice energy budgets were measured near 87.5°N during the Arctic Summer Cloud Ocean Study (ASCOS), from August to early September 2008. Surface temperature indicated four distinct temperature regimes, characterized by varying cloud, thermodynamic and solar properties. An initial warm, melt-season regime was interrupted by a 3-day cold regime where temperatures dropped from near zero to -7°C. Subsequently mean energy budget residuals remained small and near zero for 1 week until once again temperatures dropped rapidly and the energy budget residuals became negative. Energy budget transitions were dominated by the net radiative fluxes, largely controlled by the cloudiness. Variable heat, moisture and cloud distributions were associated with changing air-masses. Surface cloud radiative forcing, the net radiative effect of clouds on the surface relative to clear skies, is estimated. Shortwave cloud forcing ranged between -50 W m-2 and zero and varied significantly with surface albedo, solar zenith angle and cloud liquid water. Longwave cloud forcing was larger and generally ranged between 65 and 85 W m-2, except when the cloud fraction was tenuous or contained little liquid water; thus the net effect of the clouds was to warm the surface. Both cold periods occurred under tenuous, or altogether absent, low-level clouds containing little liquid water, effectively reducing the cloud greenhouse effect. Freeze-up progression was enhanced by a combination of increasing solar zenith angles and surface albedo, while inhibited by a large, positive surface cloud forcing until a new air-mass with considerably less cloudiness advected over the experiment area. © 2010 Springer-Verlag

Niche- and gender-dependent immune reactions in relation to the microbiota profile in pediatric patients with otitis media with effusion

Otitis media with effusion (OME) is a common inflammatory disease, primarily affecting children. OME is defined as a chronic low-grade inflammation of the middle ear (ME), without any signs of infection and with effusion persisting in the ME for more than three months. The precise pathogenesis is, however, not fully understood. Here, we comprehensively characterized and compared the host immune responses (inflammatory cells and mediators) and the overall microbial community composition (microbiota) present in matched middle ear effusion samples (MEE), external ear canal lavages, and nasopharynx (NPH) samples from children with OME. Female patients had significantly increased percentages of T lymphocytes and higher levels of a wide array of inflammatory mediators in their MEEs compared to male patients, which was unrelated to microbiota composition. The relative abundances of identified microorganisms were strongly associated with their niche of origin. Furthermore, specific inflammatory mediators were highly correlated with certain bacterial species. Interestingly, some organisms displayed a niche-driven inflammation pattern, where presence of Haemophilus spp and Corynebacterium propinquum in MEEs was accompanied by pro-inflammatory mediators, whereas their presence in NPH was accompanied by anti-inflammatory mediators. For Turicella and Alloiococcus we found exactly the opposite results, i.e., an anti-inflammatory profile when present in MEEs, whereas their presence in the NPH was accompanied by a pro-inflammatory profile. Altogether, our results indicate that immune responses in children with OME are highly niche- and microbiota-driven, but gender-based differences were also observed, providing novel insight into potential pathogenic mechanisms behind OME

Aerosols indirectly warm the Arctic

On average, airborne aerosol particles cool the Earth’s surface directly by absorbingand scattering sunlight and indirectly by influencing cloud reflectivity, life time, thicknessor extent. Here we show that over the central Arctic Ocean, where there is frequentlya lack of aerosol particles upon which clouds may form, a small increase in aerosol5loading may enhance cloudiness thereby likely causing a climatologically significantwarming at the ice-covered Arctic surface. Under these low concentration conditionscloud droplets grow to drizzle sizes and fall, even in the absence of collisions andcoalescence, thereby diminishing cloud water. Evidence from a case study suggeststhat interactions between aerosol, clouds and precipitation could be responsible for10attaining the observed low aerosol concentrations.ISSN:1680-7375ISSN:1680-736

The Arctic Summer Cloud-Ocean Study (ASCOS): Overview and experimental design

The climate in the Arctic is changing faster than anywhere else on Earth. Poorly un-derstood feedback processes relating to Arctic clouds and aerosol-cloud interactionscontribute to a poor understanding of the present changes in the Arctic climate system,and also to a large spread in projections of future climate in the Arctic. The problem is exacerbated by the paucity of research-quality observations in the central Arctic. Im-proved formulations in climate models require such observations, which can only comefrom measurements in-situ in this difficult to reach region with logistically demandingenvironmental conditions.The Arctic Summer Cloud-Ocean Study (ASCOS) was the most extensive central Arctic Ocean expedition with an atmospheric focus during the International Polar Year(IPY) 2007–2008. ASCOS focused on the study of the formation and life cycle of low-level Arctic clouds. ASCOS departed from Longyearbyen on Svalbard on 2 August andreturned on 9 September 2008. In transit into and out of the pack ice, four short re-search stations were undertaken in the Fram Strait; two in open water and two in the marginal ice zone. After traversing the pack-ice northward an ice camp was set up on12 August at 87◦21′N 01◦29′W and remained in operation through 1 September, drift-ing with the ice. During this time extensive measurements were taken of atmosphericgas and particle chemistry and physics, mesoscale and boundary-layer meteorology,marine biology and chemistry, and upper ocean physics. ASCOS provides a unique interdisciplinary data set for development and testing ofnew hypotheses on cloud processes, their interactions with the sea ice and ocean andassociated physical, chemical, and biological processes and interactions. For exam-ple, the first ever quantitative observation of bubbles in Arctic leads, combined withthe unique discovery of marine organic material, polymer gels with an origin in the ocean, inside cloud droplets suggest the possibility of primary marine organically de-rived cloud condensation nuclei in Arctic stratocumulus clouds. Direct observations ofsurface fluxes of aerosols could, however, not explain observed variability in aerosol concentrations and the balance between local and remote aerosols sources remainsopen. Lack of CCN was at times a controlling factor in low-level cloud formation, andhence for the impact of clouds on the surface energy budget. ASCOS provided de-tailed measurements of the surface energy balance from late summer melt into theinitial autumn freeze-up, and documented the effects of clouds and storms on the surface energy balance during this transition. In addition to such process-level studies, theunique, independent ASCOS data set can and is being used for validation of satelliteretrievals, operational models, and reanalysis data sets.ISSN:1680-7375ISSN:1680-736