New photogrammetric sensors for precision agriculture: the use of hyperspectral cameras

Photogrammetric and remote sensing techniques are increasingly getting used in precision agriculture to improve monitoring and management of the crops and at the same time to increase the crop yield and reduce the environmental impacts derived from the treatments.The entire production sector can benefit from the advance in technologies and the development of lightweight sensors for UAV (uncrewed aerial vehicles) with a higher spectral and spatial resolution such as the hyperspectral sensors. The hyperspectral sensors' ability for measuring hundreds of bands has impacts on the complexity and the data processing. Indeed, it is necessary to handle a considerable quantity of acquired data and select the relevant information for interventions in the agricultural area. The aims of this work are providing a survey of the UAV-based hyperspectral sensors available on the market and their acquisition technology and a global view of possible applications in the agriculture field. Moreover, the paper highlights future research developments related to this new type of device

Sled-Pull Training Decreases Rate of Force Development in Men and Women Soccer Players

Sled-pull training is a popular training method thought to increase lower extremity strength and power in athletes. Lower extremity strength and power are factors for success in sport, particularly soccer. Asymmetry is thought to negatively impact athletes, by increasing their risk of injury, and should be the focus of any training program. PURPOSE: To determine the impact of a 12-week sled pull training intervention on isometric leg rate of force development (RFD) and RFD asymmetry. METHODS: Thirty men (n = 15; 20 ± 1.5yrs, 168.28 ± 5.17cm, 73.44 ± 3.46kg) and women (n = 15; 19.58 ± 1yr, 167.07 ± 3.81cm, 62.46 ± 8.41kg) soccer players followed a 12-week sled-pull training program with sled pulls performed at 80% body weight, three times a week for six weeks, followed by a six-week maintenance phase of sled pulls at 50% bodyweight. Isometric mid-thigh pulls were performed on force platforms to measure rate of force development pre- and post-intervention. RESULTS: Sled-pull training decreased RFD from pre- to post-training in the left leg (-137.8 ± 61.5 N/s; p = 0.03), but did not significantly change RFD in the right leg (-100.2 ± 52.6 N/s; p = 0.07). Additionally, the sled-pull intervention did not significantly change RFD asymmetry from pre- to post-training (p \u3e 0.05). CONCLUSION: Sled pull training decreases the rate of force development in left leg but not the right leg in soccer athletes. Furthermore, there was no significant difference in asymmetry as a result of the training. The use of 80% body weight in sled-pull training may decrease training velocity and detrimentally impact force development

Positive and negative regulation by SLP-76/ADAP and Pyk2 of chemokine-stimulated T-lymphocyte adhesion mediated by integrin α4β1

Stimulation by chemokines of integrin α4β1-dependent T-lymphocyte adhesion is a crucial step for lymphocyte trafficking. The adaptor Vav1 is required for chemokine-activated T-cell adhesion mediated by α4β1. Conceivably, proteins associating with Vav1 could potentially modulate this adhesion. Correlating with activation by the chemokine CXCL12 of T-lymphocyte attachment to α4β1 ligands, a transient stimulation in the association of Vav1 with SLP-76, Pyk2, and ADAP was observed. Using T-cells depleted for SLP-76, ADAP, or Pyk2, or expressing Pyk2 kinase-inactive forms, we show that SLP-76 and ADAP stimulate chemokine-activated, α4β1-mediated adhesion, whereas Pyk2 opposes T-cell attachment. While CXCL12-promoted generation of high-affinity α4β1 is independent of SLP-76, ADAP, and Pyk2, the strength of α4β1-VCAM-1 interaction and cell spreading on VCAM-1 are targets of regulation by these three proteins. GTPase assays, expression of activated or dominant-negative Rac1, or combined ADAP and Pyk2 silencing indicated that Rac1 activation by CXCL12 is a common mediator response in SLP-76-, ADAP-, and Pyk2-regulated cell adhesion involving α4β1. Our data strongly suggest that chemokine-stimulated associations between Vav1, SLP-76, and ADAP facilitate Rac1 activation and α4β1-mediated adhesion, whereas Pyk2 opposes this adhesion by limiting Rac1 activation.This work was supported by grants SAF2011-24022 from Ministerio de Economía y Competitividad, RD12/0036/0061, and S2010/BMD-2314 from Comunidad de Madrid to J.T.Peer Reviewe