No Change in Perceptual or Chronotropic Outcome When Altering Preferred Step Frequency for a Short Duration

IIntroduction: Millions of individuals incorporate jogging into their physical activity routines as a leisurely pursuit and as a way to achieve positive health outcomes. People appear to choose jogging speed and the associated step frequency on pure, natural preference. Understandably, kinesthetics are important, but another important underlying factor is metabolic cost. The purpose of this work was to investigate if preferred step frequency (at a preferred jogging pace) also minimizes perceived effort (Borg Rating of Perceived Exertion, 6-20; RPE) and chronotropic stress (heart rate; HR) during a ten-minute activity bout when compared with step frequencies altered by 5%. Methods: Recreationally-trained male subjects underwent two testing visits. The first visit was used to establish RPE and HR responses during a 10-minute jogging activity at preferred speed and step frequency. On a subsequent visit, between two and four days later, with preferred speed maintained, subjects were guided by metronome to strike at either 95% or 105% of their preferred step frequency. The 10-minute runs were randomized, crossed-over, and separated by 20 minutes. RPE and HR were analyzed by repeated measures ANOVA. Results: Fourteen subjects (age: 21.1 ± 0.95; body mass index: 23.2 ± 2.5) enrolled. Preferred jogging speed (speed. 6.4 ± 1.0 miles per hour; 10.2 ± 1.6 kilometers per hour) and step frequency (steps. 161.2 ± 10.3 steps/minute) were determined at the first visit, along with RPE (11.3 ± 1.7) and HR (166.4 ± 12.7). At the second visit, preferred speed was maintained while the frequency of foot-strike was altered. Neither differences in RPE (p = 0.252; 11.3 ± 1.7, 11.6 ± 1.9, 11.8 ± 1.5) nor HR (p = 0.547; 166.4 ± 12.7, 164.7 ± 14.9, 165.2 ± 15.3) were different when comparing the preferred, 95%, and 105% step frequency trials, respectively. Although anecdotal, some subjects verbalized displeasure with the change in pace and most all appeared to markedly alter the initial foot strike phase of the gait to meet the directed foot strike tempo. Discussion: Our data must be interpreted cautiously. While altering step frequency by 5% for a short duration does not appear to alter an individual’s RPE or HR appreciably, the result during longer duration activity may not be the same. In addition, the implications for biomechanical loading and metabolic cost were not presently investigated

Impact of Optimized Breastfeeding on the Costs of Necrotizing Enterocolitis in Extremely Low Birthweight Infants

To estimate risk of NEC for ELBW infants as a function of preterm formula and maternal milk (MM) intake and calculate the impact of suboptimal feeding on NEC incidence and costs

Observational Analysis of Extratropical Cyclone Interactions with Northeast Pacific Sea Surface Temperature Anomalies

In 2013, a large upper-ocean thermal anomaly formed in the Gulf of Alaska (GOA) with sea surface temperatures (SSTs) warmer than 4 degrees Celsius above the climatological norm. This warm anomaly persisted for the next three years and has been linked to downstream effects on North American climate and negative impacts to the North Pacific ocean ecosystem. Formation of the anomaly has been associated with a persistent atmospheric high pressure ridge in the GOA which produced a lull in storm activity starting in the boreal winter of 2013 (Bond et al. 2015; Hartmann 2015). Whether this was a normal mode of oscillation within the North Pacific basin is still being debated as this warm anomaly is not unprecedented in the contemporary data record (e.g., Liang, et al. 2017). This ridging was hypothesized to suppress winter ocean heat loss to the atmosphere, leading to an anomalous upper ocean warm pool, colloquially named the blob. While storm activity was anomalously low during this and subsequent winters, we present cases where storms nonetheless significantly shaped the evolution of the GOA sea surface temperature anomalies (SSTa). During the almost four years that the anomaly resided in the GOA, it is shown here that synoptic-scale cyclones significantly eroded its surface signature and manipulated its spatial structure on synoptic timescales. The primary goal of this research is to test the hypothesis that the interaction between the upper ocean thermal anomaly and individual storm events during fall was a significant mechanism for dissipating excess heat from the warm anomaly. Not all storms, however, affected the thermal anomaly equally. Case studies using satellite observations, reanalysis, and ARGO hydrographic observations show that early fall storms produced the largest surface heat fluxes and the greatest cooling of SST compared with storms during other periods. The second goal of this study was to determine how much of the warm anomaly thermal energy was transferred to the atmosphere during individual storm events. Vertically-integrated heat budgets were computed using ARGO upper-ocean temperature profiles and surface turbulent heat and radiative flux estimates from the ECMWF and NCEP reanalyses. Storm-induced surface heat flux anomalies can account for 40-60% of the warm anomaly cooling observed with ARGO profiles during large fall storms. This rapid heat loss occurred over the course of one ARGO profile cycle, which is approximately 11 days. The erosion of the warm SSTa occurred much quicker than predicted by models forced with stochastic atmospheric forcing (Frankignoul and Hasselmann,1977; Wills and Thompson, 2018). Analysis of the individual surface flux terms indicated that the latent heat flux was the dominant contributor to heat exchange with the atmosphere during the early season storms. Given the relative importance of evaporative decay of the warm NEP-SSTa demonstrated by this analysis, this research also seeks to understand how surface latent heat flux during and in-between storm periods have been changing in the North Pacific over a 36-year time period. A monthly, spatially-varying extreme state threshold is used to separate latent heat into two separate states; intra- and inter-event periods. A power law model is used to describe the duration of these different states to determine how the duration of storms, intra-events, are changing as well as the time between storms, inter-events. East Pacific intra-event periods are found to be shorter in duration with larger flux values with respect to the mean latent heat flux during these events. This is in reference to the most recent time period of 2005-2016 relative to 1981-1992. Inter-event periods in the East Pacific were seen be getting longer with weaker fluxes. This type of pattern, if it persists, may create favorable conditions for subsurface thermal anomalies like the NEP-SSTa to be a recurring feature in the future

Meningioma DNA methylation groups identify biological drivers and therapeutic vulnerabilities

Meningiomas are the most common primary intracranial tumors. There are no effective medical therapies for meningioma patients, and new treatments have been encumbered by limited understanding of meningioma biology. Here, we use DNA methylation profiling on 565 meningiomas integrated with genetic, transcriptomic, biochemical, proteomic and single-cell approaches to show meningiomas are composed of three DNA methylation groups with distinct clinical outcomes, biological drivers and therapeutic vulnerabilities. Merlin-intact meningiomas (34%) have the best outcomes and are distinguished by NF2/Merlin regulation of susceptibility to cytotoxic therapy. Immune-enriched meningiomas (38%) have intermediate outcomes and are distinguished by immune infiltration, HLA expression and lymphatic vessels. Hypermitotic meningiomas (28%) have the worst outcomes and are distinguished by convergent genetic and epigenetic mechanisms driving the cell cycle and resistance to cytotoxic therapy. To translate these findings into clinical practice, we show cytostatic cell cycle inhibitors attenuate meningioma growth in cell culture, organoids, xenografts and patients

Impact of Optimized Breastfeeding on the Costs of Necrotizing Enterocolitis in Extremely Low Birthweight Infants

ObjectiveTo estimate risk of necrotizing enterocolitis (NEC) for extremely low birth weight (ELBW) infants as a function of preterm formula (PF) and maternal milk intake and calculate the impact of suboptimal feeding on the incidence and costs of NEC.Study designWe used aORs derived from the Glutamine Trial to perform Monte Carlo simulation of a cohort of ELBW infants under current suboptimal feeding practices, compared with a theoretical cohort in which 90% of infants received at least 98% human milk.ResultsNEC incidence among infants receiving ≥98% human milk was 1.3%; 11.1% among infants fed only PF; and 8.2% among infants fed a mixed diet (P = .002). In adjusted models, compared with infants fed predominantly human milk, we found an increased risk of NEC associated with exclusive PF (aOR = 12.1, 95% CI 1.5, 94.2), or a mixed diet (aOR 8.7, 95% CI 1.2-65.2). In Monte Carlo simulation, current feeding of ELBW infants was associated with 928 excess NEC cases and 121 excess deaths annually, compared with a model in which 90% of infants received ≥98% human milk. These models estimated an annual cost of suboptimal feeding of ELBW infants of $27.1 million (CI$24 million, $30.4 million) in direct medical costs,$563 655 (CI $476 191,$599 069) in indirect nonmedical costs, and $1.5 billion (CI$1.3 billion, $1.6 billion) in cost attributable to premature death.ConclusionsAmong ELBW infants, not being fed predominantly human milk is associated with an increased risk of NEC. Efforts to support milk production by mothers of ELBW infants may prevent infant deaths and reduce costs

Impact of Optimized Breastfeeding on the Costs of Necrotizing Enterocolitis in Extremely Low Birthweight Infants

To estimate risk of NEC for ELBW infants as a function of preterm formula and maternal milk (MM) intake and calculate the impact of suboptimal feeding on NEC incidence and costs