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1.
Phys Rev E ; 109(1-1): 014140, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38366424

ABSTRACT

This paper solves in one and two dimensions the steady noninteractive active Fokker-Planck (FP) equation and finds that its velocity distribution admits, under limiting cases, a dual behavior. Briefly, when the inertial relaxation time is smaller than the orientation time, the active FP equation admits a bimodal shape, whereas the inverse condition is seen to admit a Gaussian one. Once the velocity distribution functions are available, they are used to find their effect on the system's transport properties, such as its mean-square speed. In the process, a useful mathematical identity for the first kind Bessel function as a sum of bimodal exponential functions is spotted.

2.
Soft Matter ; 19(36): 6885-6895, 2023 Sep 20.
Article in English | MEDLINE | ID: mdl-37671426

ABSTRACT

This work deals with the mechanical properties and dynamics of an active elastic solid defined as a two-dimensional network of active stochastic particles interacting by nonlinear hard springs. By proposing a discrete model, it is numerically found that when activity in the system is turned on, the active solid stiffens as a function of propulsion forces, thus deviating from equilibrium mechanics. To understand this effect a minimal stochastic model is offered, and a physical explanation based on spatial symmetry-breaking is put forward. In addition, the dynamics of the active solid in the absence of an external stress is also studied. From this, three main features are observed to emerge, namely, a collective behavior within the active solid, a time-density fluctuation, and oscillating dynamics of the internal stresses towards a steady state.

3.
Soft Matter ; 19(33): 6287-6297, 2023 Aug 23.
Article in English | MEDLINE | ID: mdl-37554040

ABSTRACT

In this work, the free expansion of an inertial active gas in three dimensions made of spherical non-interactive active Brownian particles with both translational and rotational inertia (IABPs) is studied. After elucidating the active particles' orientational correlation in three dimensions by employing a Fokker-Planck formalism, the diffusion, mean-square speed, persistence length, reorientation time, Swim and Reynolds pressures and total pressure of this system, are obtained theoretically and corroborated by performing Langevin dynamics simulations. Afterwards, a numerical study on particles' distribution and the mechanical pressure exerted by the active gas enclosed in a cubic box and its dependence on inertia is also carried out. This experiment highlights two important observations: first, as inertia in the system grows while fixing activity, a more uniform particle distribution within the box is achieved. In other words, the classical accumulation of active particles at the walls is seen to be suppressed by inertia. Second, an active gas with translational and rotational inertiae and made of spherical particles still has a state equation which is offered here. This is supported by the fact that both the mechanical pressure definition and the bulk pressure definition as the trace of the swim and Reynolds stress tensors, coincide in the thermodynamic limit.

4.
J Med Entomol ; 60(1): 173-184, 2023 01 12.
Article in English | MEDLINE | ID: mdl-36305159

ABSTRACT

Entomological surveillance is a traditional method to measure presence, distribution, and seasonal variation of vectors in urban areas, and is essential to targeted control activities to prevent arbovirus transmission. Ovitraps as one of the main components of surveillance programs, enable determination of female oviposition behavior, as well as identification of seasonal variations of the vector. The goals of this study were 1) to detect the mosquitos (Aedes aegypti Linnaeus) and (Aedes albopictus Skuse) (Diptera:Culicidae), in Paranaguá city, 2) to assess ovitrap positive index (OPI), egg density index (EDI), and their relationship with meteorological variables, and 3) to evaluate the vertical transmission of dengue, Zika, and chikungunya in Ae. aegypti and Ae. albopictus. The study was carried out in urban areas of Paranaguá city, an important port region of Brazil, from June 2017 to November 2018. The city was divided into 16 area-clusters. Three-hundred and thirty-one ovitraps were installed monthly, remaining for four days in selected places. Kernel density maps were done to compare the spatiotemporal distribution of collected eggs. Areas which maintained constant oviposition associated with vector activity were identified and were found to overlap the area-clusters with the highest EDI. As viral RNA was not detected, vertical transmission was likely not a maintenance mechanism of arbovirus circulation in Ae. aegypti and Ae. albopictus vectors. This study reiterates the importance, efficiency, and feasibility of ovitraps to monitor the presence and dynamics of Aedes spp. populations.


Subject(s)
Aedes , Arboviruses , Dengue , Zika Virus Infection , Zika Virus , Female , Animals , Brazil , Mosquito Vectors
5.
Int J Sports Med ; 43(11): 971-977, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35760082

ABSTRACT

This study evaluated the feasibility and efficacy of voluntary sustained hyperventilation during rapid ascent to high altitude for the prevention of acute mountain sickness (AMS). Study subjects (n=32) were volunteer participants in a 2-day expedition to Mount Leoneras (4954 m), starting at 2800m (base camp at 4120 m). Subjects were randomized to either: 1) an intervention group using the voluntary hyperventilation (VH) technique targeting an end-tidal CO2 (ETCO2)<20 mmHg; or 2) a group using acetazolamide (AZ). During the expedition, respiratory rate (28±20 vs. 18±5 breaths/min, mean±SD, P<0.01) and SpO2 (95%±4% vs. 89%±5%, mean±SD, P<0.01) were higher, and ETCO2 (17±4 vs. 26±4 mmHg, mean±SD, P<0.01) was lower in the VH group compared to the AZ group - as repeatedly measured at equal fixed intervals during the ascent - showing the feasibility of the VH technique. Regarding efficacy, the incidence of 6 (40%) subjects registering an LLS score≥3 in the VH group was non-inferior to the 3 (18%) subjects in the acetazolamide group (P=0.16, power 28%). Voluntary increase in minute ventilation is a feasible technique, but - despite the underpowered non-inferiority in this small-scale proof-of-concept trial - it is not likely to be as effective as acetazolamide to prevent AMS.


Subject(s)
Altitude Sickness , Acetazolamide/therapeutic use , Acute Disease , Altitude Sickness/epidemiology , Altitude Sickness/prevention & control , Carbon Dioxide , Humans , Hyperventilation
6.
Phys Rev E ; 103(1-1): 012601, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33601560

ABSTRACT

We theoretically and computationally find a Maxwell-Boltzmann-like velocity distribution for noninteracting active matter (NAM). To achieve this, mass and moment of inertia are incorporated into the corresponding noninteracting active Fokker-Planck equation (NAFP), thus solving for the first time, the underdamped scenario of NAM following a Fokker-Planck formalism. This time, the distribution results in a bimodal symmetric expression that contains the effect of inertia on transport properties of NAM. The analytical distribution is further compared to experiments dealing with vibrobots. A generalization of the Brinkman hierarchy for NAFP is also provided and used for systematically solving the NAFP in position space. This work is an important step toward characterizing active matter using an equivalent nonequilibrium statistical mechanics.

7.
J Chem Phys ; 153(4): 044906, 2020 Jul 28.
Article in English | MEDLINE | ID: mdl-32752692

ABSTRACT

In this work, the dynamics of inertial (mass and moment of inertia) active Brownian particles trapped in a harmonic well is studied. This scenario has seen success when characterizing soft passive and active overdamped matter. Motivated by the variety of applications of this system, we analytically find the effect of translational and rotational inertia on the mean-square displacement (MSD), mean-square speed (MSS), swim, Reynolds, and total pressures of a system of inertial active Brownian particles subject to a weak and a strong harmonic trap. Following a Langevin formalism, we explicitly find that as inertia grows, the systems' MSD and total pressure are enhanced, but its MSS and swim pressure decrease. The use of Langevin dynamics simulations enables us to observe that as inertia grows, inertial active matter under a strong trap no longer "condensates" at the "border" of the trap, but it rather tends to uniformly spread in space. Our analytical results are also numerically validated.

8.
Phys Rev E ; 101(3-1): 032103, 2020 Mar.
Article in English | MEDLINE | ID: mdl-32290001

ABSTRACT

We apply the homotopy analysis method to the motion of noninteracting active Brownian particles (ABPs) under a general situation such as in the presence of external fields, external torques, or even moving on non-Euclidean geometries. Within this framework, a general expression as a series solution in time for the probability density function (PDF) satisfying the Fokker-Planck (FP) equation is elucidated. Using the latter PDF, their respective mean values (first and second moments) are also found in general. Applications of the present technique are offered by solving classic ABP situations, namely free noninteracting ABPs, ABPs under a Poiseuille flow, and even ABPs confined to move on any Riemannian manifold. To improve the convergence of the obtained series solution for each situation, Padé approximants are incorporated. It is worth mentioning that the offered methodology may exactly be applied to other fields such as chemistry, biology, or econophysics where a FP equation governs the system.

9.
Phys Rev E ; 101(1-1): 012606, 2020 Jan.
Article in English | MEDLINE | ID: mdl-32069641

ABSTRACT

It has been discovered that active matter generates novel physical quantities such as the swim pressure. This quantity arises from the exchange of extra momentum between active particles and the boundaries of the system. Given its origin, this quantity can exist at different scales; hence microorganisms and larger organisms like fish or birds generate their own swim pressure. For larger organisms or for high swimming speeds, inertia cannot necessarily be neglected; hence in this paper, we start by calculating analytically the effect of finite translational and rotational particles' inertia on the diffusion of a system of noninteracting spherical active Brownian particles. From this analysis, an enhanced diffusion coefficient due to rotational inertia is obtained, and an alternative effective persistence length and an alternative reorientation time, both sensitive to rotational inertia, are also identified. Afterwards, and to see the implications of finite inertia on bulk properties, the pressure of this system is elucidated by calculating its respective swim and Reynolds pressures. It is found that their sum becomes asymptotically sensitive to the square root of its rotational inertia. To validate our analytical results, Langevin dynamics simulations are also performed showing an excellent agreement between our theoretical predictions and the numerical results.

10.
Hum Immunol ; 81(9): 499-501, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31201078

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 161 Mexicans from the state of Nayarit living in Tepic (N = 97) and rural communities (N = 64), to obtain information regarding allelic and haplotypic frequencies. We find that the ten most frequent haplotypes found in the state of Nayarit include eight Native American and two European haplotypes. Admixture estimates revealed that the main genetic components in the state of Nayarit are Native American (50.79 ±â€¯5.03% by ML; 42.24% of Native American haplotypes) and European (37.04 ±â€¯6.21% by ML; 35.72% of European haplotypes), while African genetic component is less apparent but relatively high (12.17 ±â€¯2.50% by ML; 13.36% of African haplotypes).


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Geography , Haplotypes , Humans , Linkage Disequilibrium , Mexico , Rural Population
11.
Hum Immunol ; 81(9): 475-477, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31201080

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 250 Mexicans from the states of Baja California Norte and Baja California Sur living in Mexicali (N = 100), La Paz (N = 75), Tijuana (N = 25) and rural communities (N = 50) to obtain information regarding allelic and haplotypic frequencies. The most frequent haplotypes for the Baja California region include nine Native American and five European haplotypes. Admixture estimates revealed that the main genetic components are European (50.45 ±â€¯1.84% by ML; 42.03% of European haplotypes) and Native American (43.72 ±â€¯2.36% by ML; 40.24% of Native American haplotypes), while the African genetic component was less apparent (5.83 ±â€¯0.98% by ML; 9.36% of African haplotypes).


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Genotype , Geography, Medical , Haplotypes , Humans , Linkage Disequilibrium , Mexico , Multilocus Sequence Typing
12.
Hum Immunol ; 81(9): 482-484, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31201081

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 286 Mexicans from the state of Sinaloa living in Culiacán (N = 103) and rural communities (N = 183) to obtain information regarding allelic and haplotypic frequencies. We find that the most frequent haplotypes for the state of Sinaloa include ten Native American most probable ancestry and five European most probable ancestry haplotypes. The admixture estimates revealed that the main genetic components in the state of Sinaloa are European (62.39 ±â€¯3.47%) and Native American (37.61 ±â€¯2.85%), while the African genetic component was estimated as virtually absent (0.00 ±â€¯1.86%).


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Genotype , Geography , Haplotypes , Humans , Immunogenetics , Mexico , Rural Population
13.
Hum Immunol ; 81(9): 510-512, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31204089

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 262 Mexicans from the state of Guanajuato living in the cities of Guanajuato (N = 78), León (N = 22) and rural communities (N = 162), to obtain information regarding allelic and haplotypic frequencies. We find that the most frequent haplotypes found in the state of Guanajuato include 12 Native American and three European haplotypes. Admixture estimates revealed that the main genetic components in the state of Guanajuato are Native American (50.64 ±â€¯2.11% by ML, 43.35% of Native American haplotypes) and European (44.14 ±â€¯1.14% by ML; 39.35% of European haplotypes), while African genetic component is less apparent (5.22 ±â€¯2.08% by ML; 8.36% of African haplotypes).


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Geography , Haplotypes , Humans , Linkage Disequilibrium , Mexico , Rural Population
14.
Hum Immunol ; 81(9): 513-515, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31208822

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 104 Mexicans from the state of Colima living in the city of Colima (N = 61) and rural communities (N = 43), to obtain information regarding allelic and haplotypic frequencies. We find that the most frequent haplotypes in the state of Colima include eight Native American, two European and one African haplotype. Admixture estimates revealed that the main genetic components in the state are Native American (52.74 ±â€¯3.88% by ML; 48.10% of Native American haplotypes) and European (37.52 ±â€¯8.94% by ML; 26.66% of European haplotypes), and a relatively high African genetic component (9.74 ±â€¯8.40% by ML; 11.91% of African haplotypes).


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Geography , Haplotypes , Humans , Linkage Disequilibrium , Mexico , Rural Population
15.
Hum Immunol ; 81(9): 519-521, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31174911

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 95 Mexicans from the state of Aguascalientes to obtain information regarding allelic and haplotypic frequencies and their linkage disequilibrium. We find that the most frequent haplotypes in the state of Aguascalientes include four Native American, three European and one Asian haplotypes. Admixture estimates revealed that the main genetic components in the state of Aguascalientes are Native American (54.53 ±â€¯3.22% by ML; 44.21% of Native American haplotypes) and European (44.34 ±â€¯0.45% by ML; 40.53% of European haplotypes), and a relatively low African genetic component (1.13 ±â€¯2.33% by ML; 5.26% of African haplotypes).


Subject(s)
Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Ethnicity , Gene Frequency , Geography , Haplotypes , Humans , Linkage Disequilibrium , Mexico
16.
Hum Immunol ; 81(9): 506-509, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31174912

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 498 Mexicans from the state of Michoacán living in the city of Morelia (N = 150) and rural communities (N = 348), to obtain information regarding allelic and haplotypic frequencies. We find that the ten most frequent haplotypes found in the state of Michoacán include 12 Native American and two European haplotypes. Admixture estimates revealed that the main genetic components in the state of Michoacán are Native American (48.79 ±â€¯1.44%) and European (43.10 ±â€¯0.86%), while African genetic component is less apparent (8.11 ±â€¯0.85%). Our findings add to the growing knowledge on the population genetics of Western Mexico and provide new HLA data on populations from Michoacán.


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Geography , Haplotypes , Humans , Linkage Disequilibrium , Mexico , Rural Population
17.
Hum Immunol ; 81(9): 502-505, 2020 Sep.
Article in English | MEDLINE | ID: mdl-31174913

ABSTRACT

We studied HLA class I (HLA-A, -B) and class II (HLA-DRB1, -DQB1) alleles by PCR-SSP based typing in 2046 Mexicans from the state of Jalisco living in the city of Guadalajara (N = 1189), Tlajomulco (N = 30), Tlaquepaque (N = 39), Tonalá (N = 35), Zapopan (N = 168) and rural communities (N = 585), to obtain information regarding allelic and haplotypic frequencies. We find that the most frequent haplotypes found in the state of Jalisco include nine Native American most probable ancestry and three European haplotypes. Admixture estimates revealed that the main genetic components in the state of Jalisco are European (48.45 ±â€¯1.18% by ML; 41.66% of European haplotypes) and Native American (44.02 ±â€¯1.24% by ML; 39.86% of Native American haplotypes), while African genetic component is less apparent (7.53 ±â€¯0.30% by ML; 9.62% of African haplotypes).


Subject(s)
Ethnicity/genetics , Genetic Variation , Genetics, Population , HLA Antigens/genetics , Alleles , Gene Frequency , Geography , Haplotypes , Humans , Linkage Disequilibrium , Mexico , Rural Population
18.
Soft Matter ; 14(48): 9928-9936, 2018 Dec 12.
Article in English | MEDLINE | ID: mdl-30488931

ABSTRACT

We formulate the dynamics of overdamped Brownian active particles (swimmers) moving on any Riemannian 2-manifold. To characterize such dynamics at short times, an analytical expression for the variance of swimmers diffusing on any Riemmanian 2-manifold is derived. To show the generality of the present work, we apply the latter dynamics to swimmers moving on the surface of a spheroid and a torus, and offer analytical expressions for both their long-time variances and steady angular marginal probability density functions. Finally, Brownian dynamics simulations are used to validate our theoretical findings.

19.
Phys Rev E ; 97(3-1): 032603, 2018 Mar.
Article in English | MEDLINE | ID: mdl-29776142

ABSTRACT

We present analytical expressions for the mean-square displacement of self-driven particles in general linear flows and trapped in a harmonic potential. The general expressions are applied to three types of linear flows, namely, shear flow, solid-body rotation flow, and extensional flow. By using Brownian dynamics simulations, the effect of trapping and external linear flows on the particles' distribution is also elucidated. These simulations also enabled us to validate our theoretical results.

20.
Phys Rev E ; 96(2-1): 022606, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28950475

ABSTRACT

We present the dynamics of overdamped Brownian self-propelled particles moving on the surface of a sphere. The effect of self-propulsion on the diffusion of these particles is elucidated by determining their angular (azimuthal and polar) mean-square displacement. Short- and long-times analytical expressions for their angular mean-square displacement are offered. Finally, the particles' steady marginal angular probability density functions are also elucidated.

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