In this investigation, ROS-based robust attitude control is designed for a two-wheeled self-balancing mobile robot (TWSBR) using the active disturbance rejection control (ADRC) technique. The ...designed ROS framework contemplates communication between topics for the desired robot commands and distributed framework design. This open architecture allows the integration of sensors, actuators, and processors. The architecture includes User-Friendly Interface, storage, navigation, control, and drivers. The low-cost robot was designed for educational purposes. It uses an Arduino Mega as a low-level processing unit, a Raspberry Pi 4 as a companion computer where high-level commands are processed, an MPU6050 Inertial Measurement Unit sensor, DC motors GW4058-555 with quadrature type encoder with two phases, the VNH2SP30 controller module used as the power stage and a Lithium Polymer (Li-Po) battery (11.1 V, 2200 mah) is used as the power source. The robust control algorithm is designed through the ADRC methodology based on the extended state observer (ESO). The ESO simultaneously estimates external disturbances, model uncertainties, and unmodeled dynamics such as friction, engine wear, and tire slippage. The stability of the developed controller is analyzed via the Lyapunov stability theory. Real-time experimental results are carried out under the regulation and rejection of external disturbances. The control algorithm is light and easy to implement and adjust in integrated systems with low computer resources.
Abstract
We report the discovery of Pegasus IV, an ultra-faint dwarf galaxy found in archival data from the Dark Energy Camera processed by the DECam Local Volume Exploration Survey. Pegasus IV is a ...compact, ultra-faint stellar system (
r
1
/
2
=
41
−
6
+
8
pc;
M
V
= −4.25 ± 0.2 mag) located at a heliocentric distance of
90
−
6
+
4
kpc
. Based on spectra of seven nonvariable member stars observed with Magellan/IMACS, we confidently resolve Pegasus IV’s velocity dispersion, measuring
σ
v
=
3.3
−
1.1
+
1.7
km s
−1
(after excluding three velocity outliers); this implies a mass-to-light ratio of
M
1
/
2
/
L
V
,
1
/
2
=
167
−
99
+
224
M
⊙
/
L
⊙
for the system. From the five stars with the highest signal-to-noise spectra, we also measure a systemic metallicity of Fe/H =
−
2.63
−
0.30
+
0.26
dex, making Pegasus IV one of the most metal-poor ultra-faint dwarfs. We tentatively resolve a nonzero metallicity dispersion for the system. These measurements provide strong evidence that Pegasus IV is a dark-matter-dominated dwarf galaxy, rather than a star cluster. We measure Pegasus IV’s proper motion using data from Gaia Early Data Release 3, finding (
μ
α
*
,
μ
δ
) = (0.33 ± 0.07, −0.21 ± 0.08) mas yr
−1
. When combined with our measured systemic velocity, this proper motion suggests that Pegasus IV is on an elliptical, retrograde orbit, and is currently near its orbital apocenter. Lastly, we identify three potential RR Lyrae variable stars within Pegasus IV, including one candidate member located more than 10 half-light radii away from the system’s centroid. The discovery of yet another ultra-faint dwarf galaxy strongly suggests that the census of Milky Way satellites is still incomplete, even within 100 kpc.
The liver X receptor agonist, GW3965, improves cognition in Alzheimer’s disease (AD) mouse models. Here, we determined if short-term GW3965 treatment induces changes in the DNA methylation state of ...the hippocampus, which are associated with cognitive improvement. Twenty-four-month-old triple-transgenic AD (3xTg-AD) mice were treated with GW3965 (50 mg/kg/day for 6 days). DNA methylation state was examined by modified bisulfite conversion and hybridization on Illumina Infinium Methylation BeadChip 450 k arrays. The Morris water maze was used for behavioral analysis. Our results show in addition to improvement in cognition methylation changes in 39 of 13,715 interrogated probes in treated 3xTg-AD mice compared with untreated 3xTg-AD mice. These changes in methylation probes include 29 gene loci. Importantly, changes in methylation status were mainly from synapse-related genes (
SYP
,
SYN1
, and
DLG3
) and neurogenesis-associated genes (
HMGB3
and
RBBP7
). Thus, our results indicate that liver X receptors (LXR) agonist treatment induces rapid changes in DNA methylation, particularly in loci associated with genes involved in neurogenesis and synaptic function. Our results suggest a new potential mechanism to explain the beneficial effect of GW3965.
Abstract
We present the discovery of a candidate ultra-faint Milky-Way satellite, Eridanus IV (DELVE J0505−0931), detected in photometric data from the DECam Local Volume Exploration survey (DELVE). ...Eridanus IV is a faint (
M
V
= − 4.7 ± 0.2), extended (
r
1
/
2
=
75
−
13
+
16
pc
), and elliptical (
ϵ
= 0.54 ± 0.1) system at a heliocentric distance of
76.7
−
6.1
+
4.0
kpc
, with a stellar population that is well described by an old, metal-poor isochrone (age of
τ
∼ 13.0 Gyr and metallicity of Fe/H ≲ − 2.1 dex). These properties are consistent with the known population of ultra-faint Milky-Way satellite galaxies. Eridanus IV is also prominently detected using proper-motion measurements from Gaia Early Data Release 3, with a systemic proper motion of
(
μ
α
cos
δ
,
μ
δ
)
=
(
+
0.25
±
0.06
,
−
0.10
±
0.05
)
mas yr
−1
measured from its horizontal branch and red-giant-branch member stars. We find that the spatial distribution of likely member stars hints at the possibility that the system is undergoing tidal disruption.
Ports are gateways for many marine organisms transported by ships worldwide, especially non-indigenous species (NIS). In this study carried out in North Iberian ports (Cantabrian Sea, Bay of Biscay) ...we have observed 38% of exotic macroinvertebrates. Four species, namely the barnacle Austrominius modestus, the tubeworm Ficopomatus enigmaticus, the Pacific oyster Crassostrea gigas and the pygmy mussel Xenostrobus securis, exhibited clear signs of invasiveness. A total of 671 barcode (cytochrome oxidase subunit I or 18S rRNA) genes were obtained and confirmed the species status of some cryptic NIS. Negative and significant correlation between diversity estimators of native biota and proportion of NIS suggests biotic resistance in ports. This could be applied to management of port biota for contributing to prevent the settlement of biopollutants in these areas which are very sensitive to biological invasions.
•Marine biological invasions often use ports as gateways.•Fouling macrobiota was sampled from eight ports within south Bay of Biscay.•DNA barcoding helped to identify phenotypically plastic species.•Negative correlation between native biodiversity and frequency of exotics was found.•Results suggest native biodiversity protects against invasions in ports.
► MIF polymorphisms are involved in rheumatoid arthritis susceptibility. ► −794 CATT7 allele is associated with early onset RA. ► MIF and TNFα soluble levels correlate positively in RA. ► MIF levels ...correlated negatively with years of disease duration.
Macrophage migration inhibitory factor (MIF) is an upstream pro-inflammatory cytokine that is associated with the pathogenesis of autoimmune inflammatory diseases including rheumatoid arthritis (RA). Two polymorphisms in the upstream region exist in the MIF gene and are associated with RA susceptibility or severity in different populations. In this case-control study, we investigated whether MIF polymorphisms are associated with RA susceptibility or activity in a western Mexican population .The relationship of MIF levels with clinical features of disease also was assessed. Genotyping of the −794 CATT5–8 (rs5844572) and the −173 G>C (rs755622) polymorphisms was performed by PCR and PCR-RFLP respectively on 226 RA patients and 210 healthy subjects. Serum MIF levels were determined by ELISA. We found a significant association between the −794 CATT5–8 6,7 MIF genotype with RA. Moreover, we detected an association between the −794 CATT7 allele with early onset RA. The −794 CATT7 and −173*C alleles, which are in linkage disequilibrium, were associated with high disease activity on RA patients. A positive correlation between circulating MIF levels and C-reactive protein, erythrocyte sedimentation rate, rheumatoid factor, anti-citrullinated protein/peptides antibodies and TNFα was detected. MIF levels appear to be associated with disease progression rather than disease activity, which is distinct from the established relationship between disease activity and TNFα levels. In conclusion, the MIF gene and protein are associated with RA in a western Mexican population, with a main contribution onto early onset and early stages of disease.
In this paper a Fractional PID Control is presented. This control was designed for a hydropower plant with six generation units working in an alternation scheme. The parameters and other features of ...such a set of hydrogeneration units have been used to perform the respective tuning up. In order to assess the behavior of this controlled system, a model of such nonlinear plant is regulated through a classical PID by classical linearization of its set points, and then a pseudo-derivative part is substituted into a Fractional PID. Both groups of signals contain variations of voltage suggesting some abrupt changes in the supply of electricity fed to the network. Both sets of resulting signals are compared; the simulations show that the Fractional PID has a faster response with respect to those plots obtained from the classical PID used.
•Nonlinear modeling of a hydroelectric pumped-storage station.•Hybrid reduced order model of a hydroelectric pumped-storage station.•Evaluation of Gain Scheduling Predictive Controller in a ...hydropower station model.
This work deals with the evaluation of the performance of a predictive control applied to a nonlinear model of Dinorwig a pumped storage hydropower plant. The controller uses a piecewise-linear plant model for prediction and is gain-scheduled according to the number of active hydro-generation Units (ranging from 1 to 6). Simulated results are presented to evaluate the performance of the predictive controller, which is compared with a gain-scheduled PI controller that has anti-windup features; this controller was tuned using the current practical values. The results show that the response, to various changes in the plant operating conditions, obtained with the predictive controller is faster and less sensitive than the one obtained from the PI controller. The results also show how reduced-order models can be used for prediction, allowing the reduction of the computing time (or the computing cost) without compromising the closed-loop performance control signal.
Daytime restricted feeding (2 h of food access from 12.00 to 14.00 hours for 3 weeks) is an experimental protocol that modifies the relationship between metabolic networks and the circadian molecular ...clock. The precise anatomical locus that controls the biochemical and physiological adaptations to optimise nutrient use is unknown. We explored the changes in liver oxidative lipid handling, such as β-oxidation and its regulation, as well as adaptations in the lipoprotein profile. It was found that daytime restricted feeding promoted an elevation of circulating ketone bodies before mealtime, an altered hepatic daily rhythmicity of 14CO2 production from radioactive palmitic acid, and an up-regulation of the fatty acid oxidation activators, the α-subunit of AMP-activated protein kinase (AMPK), the deacetylase silent mating type information regulation homolog 1, and the transcriptional factor PPARγ-1α coactivator. An increased localisation of phosphorylated α-subunit of AMPK in the periportal hepatocytes was also observed. Liver hepatic lipase C, important for lipoprotein transformation, showed a change of daily phase with a peak at the time of food access. In serum, there was an increase of LDL, which was responsible for a net elevation of circulating cholesterol. We conclude that our results indicate an enhanced fasting response in the liver during daily synchronisation to food access, which involves altered metabolic and cellular control of fatty acid oxidation as well a significant elevation of serum LDL. These adaptations could be part of the metabolic input that underlies the expression of the food-entrained oscillator.
Visible-light photoactive (Na
0.5
Bi
0.5
)TiO
3
(NBT)-based heterojunctions have demonstrated their applicability in environmental remediation. The photocatalytic properties of NBT-based coatings are ...here reported. NBT-based materials were deposited by oxyacetylene flame spray (FS). The physicochemical properties were analyzed as a function of the spraying parameters: fuel/oxygen ratio (F/O), stand-off distance (SOD), and total gas flow (TF). A flame with reducing characteristics promotes the formation of TiO
2
(anatase and rutile) and Bi
4
Ti
3
O
12
, while an oxidizing flame results in coatings rich in NBT and Bi
4
Ti
3
O
12
. The SOD mainly influences the degree of crystallinity, which is higher at shorter distances. Optical properties estimated by UV–VIS diffuse reflectance confirmed an increase in light absorption after the FS process, with an
E
g
red shift from 3.32 eV of the NBT powder to 2.63-2.96 eV of the coatings. These values are dependent on the F/O, with a significant
E
g
narrowing under reducing conditions. Photoelectrochemical measurements revealed that faster electron collection is obtained due to the transformations occurring throughout the FS process while still retaining nearly 70 and 88% of the photocurrent density (
j
ph
) at UV and visible light, respectively. These results suggest the great potential of the FS methodology to produce multiphase photocatalytic coatings by tuning the processing parameters.
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