U.S. Agricultural Policy in 2004: Ripe for Reform, Repackaging, or Routine?

Agricultural and Food Policy,

Expiratory Flow Limitation in Elite Youth Cyclists

Expiratory flow limitation (EFL) has been reported in pre-pubescent adolescents and elite, adult endurance athletes; however, the occurrence of EFL in elite adolescent endurance athletes has not been determined. Purpose: To determine incidence and severity of EFL in elite youth male cyclists of adolescent age. We hypothesized that elite, endurance trained youth will experience a higher prevalence and severity of EFL and dyspnea compared to an untrained control group. Pulmonary function will be similar pre- to post-exercise with bronchodilation occurring in both groups. Methods: 12 elite endurance- trained (ET) youth male cyclists (16.3 ± 1.0 years; 176.5 ± 6.2 cm; 64.2 ± 5.9 kg) and 12 recreationally active males (CON) (17.6 ± 2.2 years; 177.9 ± 7.1 cm; 74.8 ± 11.2 kg) completed an incremental test to exhaustion to determine peak oxygen consumption (VO2peak) on a cycle ergometer. Heart rate and ventilation (VE) were assessed throughout the exercise test. Dyspnea and ratings of perceived exertion (RPE) were assessed at the end of each stage. Subjects performed maximal flow volume loops (forced vital capacity (FVC), forced expiratory volume in 1-second (FEV1), FEV1/FVC, forced expiratory flow between 25-75% of FVC (FEF25-75%) and peak expiratory flow (PEF)) pre- and post- exercise. The occurrence and severity of EFL was quantified as the percentage of the expiratory tidal volume that overlapped with the maximum flow volume loop. Results: VO2peak in the ET group was 69.4±7.0 mL/kg/min and 45.7±3.9 ml/kg/min in the CON group. Peak power (390 ± 57 W vs. 273 ± 45 W) and peak VE (158 ± 18 L/min) were higher in ET vs. CON (124.7 ± 15.3). The ET group experienced significant EFL at VO2peak (p \u3c 0.001), with 11/12 subjects exhibiting flow limitation. In the CON group, 5/12 subjects exhibited EFL. There was a significant change in pulmonary function from pre- to post-exercise in FEV1 in both groups, with greater post-exercise bronchodilation in the CON group. There was no change in FVC, FEV1/FVC, FEF25-75% of FVC or PEF. The ET cyclists also had higher dyspnea ratings and RPE at peak exercise (8.5 ± 1.2, p \u3c 0.01; 18.5 ± 1.2) than CON (6.3 ± 2.6, 17.2 ± 1.6). Conclusions: Elite youth male cyclists have a higher occurrence of and severity of EFL at maximal exercise than recreationally active counterparts, which may limit exercise tolerance. Considering subjects are of pubertal age, or nearing the end of puberty, the participants may outgrow their flow limitation

Nanoplastic Settling Potential in Saline Environments

Nanoplastics are produced industrially for uses such as cosmetics and also generated by erosion of consumer plastic products. Nanoplastic properties are largely unstudied; understanding how these particles act will allow us to evaluate their environmental impact, design methods of detection, and remediation. Microplastics bioaccumulate and absorb harmful chemicals. Smaller nano-sized plastics may have an even higher affinity for chemical adsorbtion due to high surface areas, making these tiny particles a contaminant of emerging concern.https://digitalcommons.mtech.edu/urp_aug_2017/1003/thumbnail.jp

Improved Cardiorespiratory Fitness Is Associated with Increased Cortical Thickness in Mild Cognitive Impairment

Cortical atrophy is a biomarker of Alzheimer’s disease (AD) that correlates with clinical symptoms. This study examined changes in cortical thickness from before to after an exercise intervention in mild cognitive impairment (MCI) and healthy elders. Thirty physically inactive older adults (14 MCI, 16 healthy controls) underwent MRI before and after participating in a 12-week moderate intensity walking intervention. Participants were between the ages of 61 and 88. Change in cardiorespiratory fitness was assessed using residualized scores of the peak rate of oxygen consumption (V̇O2peak) from pre- to post-intervention. Structural magnetic resonance images were processed using FreeSurfer v5.1.0. V̇O2peak increased an average of 8.49%, which was comparable between MCI and healthy elders. Overall, cortical thickness was stable except for a significant decrease in the right fusiform gyrus in both groups. However, improvement in cardiorespiratory fitness due to the intervention (V̇O2peak) was positively correlated with cortical thickness change in the bilateral insula, precentral gyri, precuneus, posterior cingulate, and inferior and superior frontal cortices. Moreover, MCI participants exhibited stronger positive correlations compared to healthy elders in the left insula and superior temporal gyrus. A 12-week moderate intensity walking intervention led to significantly improved fitness in both MCI and healthy elders. Improved V̇O2peak was associated with widespread increased cortical thickness, which was similar between MCI and healthy elders. Thus, regular exercise may be an especially beneficial intervention to counteract cortical atrophy in all risk groups, and may provide protection against future cognitive decline in both healthy elders and MCI

The Effects of Country-of-Origin and Attitude Functions on Luxury Brand Purchase

The purpose of this study was to examine the effects of country-of-origin on young consumers’ attitude and luxury brand purchase intentions. This study extends the “Functional Theories of Attitudes” by adding materialistic function to social-adjustive, value-expressive, hedonic, and utilitarian functions. A total of 418 online survey responses were used to test the proposed model. Results identified the utilitarian function was not reliable, but materialistic function was a reliable construct. Results found that attitude is a multidimensional construct consisting of social-adjustive, value-expressive, materialistic, and hedonic functions. Country-of-origin positively influenced attitude toward luxury brand, which positively influenced luxury brand purchase intentions. Further multiple regression analysis found a significant direct path between country-of-origin and luxury brand purchase, which showed much stronger impact than the effect of attitude on purchase intentions. These findings provide theoretical and managerial implications for luxury brand managers

Exercise Training and Functional Connectivity Changes in Mild Cognitive Empairment and Healthy Elders

Background: Effective interventions are needed to improve brain function in mild cognitive impairment (MCI), an early stage of Alzheimer’s disease (AD). The posterior cingulate cortex (PCC)/precuneus is a hub of the default mode network (DMN) and is preferentially vulnerable to disruption of functional connectivity in MCI and AD. Objective: We investigated whether 12 weeks of aerobic exercise could enhance functional connectivity of the PCC/precuneus in MCI and healthy elders. Methods: Sixteen MCI and 16 healthy elders (age range = 60–88) engaged in a supervised 12-week walking exercise intervention. Functional MRI was acquired at rest; the PCC/precuneus was used as a seed for correlated brain activity maps. Results: A linear mixed effects model revealed a significant interaction in the right parietal lobe: the MCI group showed increased connectivity while the healthy elders showed decreased connectivity. In addition, both groups showed increased connectivity with the left postcentral gyrus. Comparing pre to post intervention changes within each group, the MCI group showed increased connectivity in 10 regions spanning frontal, parietal, temporal and insular lobes, and the cerebellum. Healthy elders did not demonstrate any significant connectivity changes. Conclusion: The observed results show increased functional connectivity of the PCC/precuneus in individuals with MCI after 12 weeks of moderate intensity walking exercise training. The protective effects of exercise training on cognition may be realized through the enhancement of neural recruitment mechanisms, which may possibly increase cognitive reserve. Whether these effects of exercise training may delay further cognitive decline in patients diagnosed with MCI remains to be demonstrated

Analyzing Spatio-Temporal Mechanisms of Land Subsidence in the Parowan Valley, Utah, USA

Parowan Valley, Utah (USA), is an agricultural region experiencing rapid subsidence due to extensive groundwater extraction from aquifers with a significant portion of fine-grained sediments. To analyze the subsidence spatio-temporally, time-series Interferometric Synthetic Aperture Radar (InSAR) of 155 Sentinel-1 C-band scenes were processed. These data showed approximately 30 cm of ground subsidence in Parowan Valley from 2014 to 2020. Because of the high temporal sampling rate of the Sentinel-1 satellite (12-day cycle), it is possible to determine the seasonal changes of ground deformation and relate this to groundwater extraction. To better understand the relationship between ground deformation and groundwater extraction in the Parowan Valley, temporal changes in hydraulic head data from US Geological Survey observation wells were monitored. Additionally, well logs were analyzed and used to construct a map that showed the percentage of fine-grained material in the subsurface. The investigation of hydraulic head and geology, together with InSAR-derived ground displacement data, indicates that the most subsidence occurs where there is a co-occurrence of high groundwater demand and a high percentage of fine-grained sediments, but recharge likely plays a role in mitigating subsidence in some areas. The subsidence developed in Parowan Valley shows a long-term trend as well as seasonal variation and appears to be influenced by both agricultural activity and annual precipitation

A New Class of non-Hermitian Quantum Hamiltonians with PT Symmetry

In a remarkable development Bender and coworkers have shown that it is possible to formulate quantum mechanics consistently even if the Hamiltonian and other observables are not Hermitian. Their formulation, dubbed PT quantum mechanics, replaces hermiticity by another set of requirements, notably that the Hamiltonian should be invariant under the discrete symmetry PT, where P denotes parity and T denotes time reversal. All prior work has focused on the case that time reversal is even (T^2 = 1). We generalize the formalism to the case of odd time reversal (T^2 = -1). We discover an analogue of Kramer's theorem for PT quantum mechanics, present a prototypical example of a PT quantum system with odd time reversal, and discuss potential applications of the formalism. Odd time reversal symmetry applies to fermionic systems including quarks and leptons and a plethora of models in nuclear, atomic and condensed matter physics. PT quantum mechanics makes it possible to enlarge the set of possible Hamiltonians that physicists could deploy to describe fundamental physics beyond the standard model or for the effective description of condensed matter phenomena.Comment: Replaced submitted version with accepted version; to appear in Phys Rev

Detecting Chameleon Dark Energy via Electrostatic Analogy

The late-time accelerated expansion of the universe could be caused by a scalar field that is screened on small scales, as in chameleon or symmetron scenarios. We present an analogy between thin shell configurations of such scalar fields and electrostatics, which allows calculation of the field profile for general extended bodies. Interestingly, the field demonstrates a `lightning rod' effect, where it becomes enhanced near the ends of a pointy or elongated object. Drawing from this correspondence, we show that non-spherical test bodies immersed in a background field will experience a net torque caused by the scalar field. This effect, with no counterpart in the gravitational case, can be potentially tested in future experiments.Comment: journal accepted versio

Palatability of teff grass by horses

Most forages commonly used to feed horses have potential detriments including blister beetles or excessive fiber concentrations. Teff grass (T), a warm-season annual forage, has the potential to be a good alternative for horses because of its lack of observed disorders. Our objective was to compare preference by horses for T harvested under different conditions with that of bermudagrass (B) harvested at two maturities. Six different forages were evaluated: T harvested at the late vegetative stage (TLV), at late bloom but that incurred 33 mm of rainfall between mowing and baling (TLBR), with caryopsis visible (TES), or at soft dough (TSD), and B harvested at late vegetative (BLV) and mid-bloom (BMB) growth stages. Five mature horses were used in a balanced incomplete block design where each horse received a different combination of 4 forages each day for 6 d. The 4 different forages were suspended in hay nets in each corner of each stall, and each hay was offered at 50% of the average daily hay consumption measured during a 12-d adaptation period. Forage preference as measured by individual forage dry matter (DM) consumption (kg and % of total DM consumed across the 4 forages) was greatest (P \u3c 0.05) from TLV followed by BLV. Preference (kg and % of total DM consumed) of BMB was greater (P \u3c 0.05) than that of TMBR, TES, and TSD, which did not differ from each other (P ≥ 0.63). Therefore, within a specific growth stage, horses apparently preferred teff grass, but effects of maturity and rainfall had a more dramatic effect on preference by horses than forage species