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Latin America faces a shortage in radiotherapy (RT) units and qualified personnel for timely and high-quality treatment of cancer patients. Investing in equitable and inclusive access to RT over the next decade would prevent thousands of deaths. Measuring the investment gap and payoff is necessary for stakeholder discussions and capacity planning efforts.Data were collected from the International Atomic Energy Agency's Directory of Radiotherapy Centers, industry stakeholders, and individual surveys sent to national scientific societies. Nationwide data on available devices and personnel were compiled. The 10 most common cancers in 2020 with RT indication and their respective incidence rates were considered for gap calculations. The gross 2-year financial return on investment (ROI) was calculated based on an average monthly salary across Latin America. A 10-year cost projection was calculated according to the estimated population dynamics for the period until 2030.Eleven countries were included in the study, accounting for 557,213,447 people in 2020 and 561 RT facilities. Approximately 1,065,684 new cancer cases were diagnosed, and a mean density of 768,469 (SD ± 392,778) people per available unit was found. By projecting the currently available treatment fractions to determine those required in 2030, it was found that 62.3% and 130.8% increases in external beam radiotherapy (EBRT) and brachytherapy (BT) units are needed from the baseline, respectively. An overall regional investment of approximately US$349,650,480 in 2020 would have covered the existing demand. Whereas, an investment of US$872,889,949 will be necessary by 2030, with the expectation of a 2-year post-treatment gross ROI of over US$2.1 billion from patients treated in 2030 only.Investment in RT services is lagging in Latin America in terms of the population's needs. An accelerated outlay could save additional lives during the next decade, create a self-sustaining system, and reduce region-wide inequities in cancer care access. Cash flow analyses are warranted to tailor precise national-level intervention strategies.

Educators are beginning to consider the physical learning environment as an additional resource in meeting learning outcomes in modern classrooms. In order to better utilise classroom space, schools have begun to eliminate desks and chairs and to replace ‘traditional’ furniture with ‘flexible’ furniture that is capable of multiple reconfigurations to facilitate teaching and learning. The impact of flexible furniture in elementary classrooms has had little exploration. We investigated the various impacts of flexible furniture paired with teacher professional development (PD) on the elementary classroom. A total of 10 classrooms were included in the study of 3rd and 4th graders (N = 206 students). Classrooms were observed biweekly for 8 weeks and assigned to one of two groups: Group A received PD and flexible furniture, whereas Group B maintained traditional furniture. During observations, three students were randomly selected from each classroom and continuously monitored throughout each observation (n = 30 students). First, a between-groups design and analysis of covariance (ANCOVA) was employed to assess the effect of the intervention using pre-intervention self-assessment results as the covariate. As predicted, students who experienced flexible furniture reported greater satisfaction with the learning environment than did peers with traditional furniture. Secondly, a series of independent samples t test demonstrated that classrooms with flexible furniture provided more opportunities for student autonomy and use of furniture for learning. Insight on flexible furniture, its impact in the elementary classroom, implications and future research are discussed.

La criopreservación permite la conservación de recursos genéticos de peces en peligro de extinción y mejora procesos reproductivos en cautiverio. El objetivo del estudio fue evaluar semen de dorada con tres crioprotectores internos a dos porcentajes de inclusión. Se utilizaron reproductores en fase espermiación (n=12), inducidos con 5 mg de extracto hipofisario de carpa/Kg. Seis horas después el semen fresco (SF) fue colectado y diluido en soluciones crioprotectores compuesta por glucosa 6%, yema de huevo 12% y los crioprotectores dimetilsulfóxido (DMSO), dimetilacetamida (DMA) y etilenglicol (EG) a porcentajes de inclusión de 5 y 10%; luego empacado en pajillas de 0.5 mL y congelado con vapores de nitrógeno. El semen fue descongelado quince días después en baño serológico. La calidad del SF, precongelado (SP) y descongelado (SD) fue evaluada con el software SCA® (Sperm Class Analyzer). Fue evaluada la movilidad total (Mt), tipos de movilidad, velocidades, progresividad total y concentración espermática. En SD se estimaron los daños en membrana espermática (D-Mem), mitocondria (D-Mit) y fragmentación de DNA (F-DNA) mediante citometría de flujo. La Mt del SF fue de 97.0±7.0%, en SP fue de 82.5±17.9% y en SD de 45.4±13.6%; siendo mayor cuando fue tratado con DMSO10% (p0.05). Los resultados obtenidos permiten inferir que los crioprotectores evaluados incluidos a 5 y 10%, son una alternativa viable para la crioconservación de semen de dorada. Cryopreservation allows the conservation of genetic resources of fish in danger of extinction and improves reproductive processes in captivity. This research aimed to evaluate semen from dorada with three cryoprotectants at two inclusionpercentages. Spermation phase breeding males (n=12) were used, induced with 5 mg of carp pituitary extract/Kg. Six hours later, fresh semen (SF) was collected and diluted in cryoprotectant solutions composed of glucose 6%, egg yolk 12% and thecryoprotectants dimethylsulfoxide (DMSO), dimethylacetamide (DMA) and ethylene glycol (EG) at inclusion percentages of 5 and 10%; then packed in 0.5 mL straws and frozen with nitrogen vapors. The semen was thawed fifteen days later in a serological bath. The quality of the FS, pre-frozen (PS) and thawed (TS) was evaluated with the support of the SCA® software (Sperm Class Analyzer). Total motility (Mt), types of motility, velocities, total progressivity and sperm concentration were evaluated. Damage to the sperm membrane (D-Mem), mitochondria (D-Mit) and DNA fragmentation (F-DNA) were measured by flow cytometry in TS. The Mt of SF was 97.0±7.0%, in SP it was 82.5±17.9% and in SD it was 45.413.6%, being higher when treated with DMSO10% (p 0.05). The results allow us to infer that the evaluated cryoprotectants, including 5 and 10%, are a viable alternative forthe cryopreservation of dorada sperm.

The self-organization of dust grains into stable filamentary dust structures (or "chains") largely depends on dynamic interactions between the individual charged dust grains and the complex electric potential arising from the distribution of charges within the local plasma environment. Recent studies have shown that the positive column of the gas discharge plasma in the Plasmakristall-4 (PK-4) experiment onboard the International Space Station (ISS) supports the presence of fast-moving ionization waves, which lead to variations of plasma parameters by up to an order of magnitude from the average background values. The highly-variable environment resulting from ionization waves may have interesting implications for the dynamics and self-organization of dust particles, particularly concerning the formation and stability of dust chains. Here we investigate the electric potential surrounding dust chains in the PK-4 by employing a molecular dynamics model of the dust and ions with boundary conditions supplied by a Particle-in-Cell with Monte Carlo collisions (PIC-MCC) simulation of the ionization waves. The model is used to examine the effects of the plasma conditions within different regions of the ionization wave and compare the resulting dust structure to that obtained by employing the time-averaged plasma conditions. Comparison between simulated dust chains and experimental data from the PK-4 shows that the time-averaged plasma conditions do not accurately reproduce observed results for dust behavior, indicating that more careful treatment of plasma conditions in the presence of ionization waves is required. It is further shown that commonly used analytic forms of the electric potential do not accurately describe the electric potential near charged dust grains under these plasma conditions., Comment: 15 pages, 14 figures

There is a variety of cases in nature when the action–reaction symmetry is broken. In particular, suitable conditions for this are realized in colloidal suspensions and complex plasmas. Since the first theories and simulations of the nonreciprocal effective interactions between microparticles in complex plasmas were published in 1995–1996, there have been hundreds of studies in the theoretical development of this theme. However, despite such a rich theoretical background, one of the important unsolved problems is a direct experimental determination of the nonreciprocal interparticle interaction forces. Here, we studied experimentally in detail the forces of the nonreciprocal effective interaction between microparticles suspended a radio-frequency produced plasma sheath. For this purpose, an experimental method based on an analysis of the spectral density of random processes in an open dissipative two-particle system was developed. In contrast to previous investigations, the proposed method takes into account random and dissipative processes in the system, does not require a special design of the experimental setup and any external perturbations, pre-measurements of external fields and any assumptions about the type of interaction. We found that even small charge changes of one particle, caused by its thermal motion in a wake field of another particle, can lead to a significant change in the effective (measurable) interaction between the particles.

The lead authors failed to name two collaborators as co-authors. The authors listed should include: Miss Claudia L. Compean-Gonzalez (ORCID: 0000-0002-2367-8450) and Dr. Giacomo Ceccone (ORCID: 0000-0003-4637-0771). These co-authors participated in VAMAS project A27, provided data that were analyzed and presented in this publication (and supporting information), and reviewed the manuscript before submission.

The self-diffusion phenomenon in a two-dimensional dusty plasma at extremely strong (effective) magnetic fields is studied experimentally and by means of molecular dynamics simulations. In the experiment the high magnetic field is introduced by rotating the particle cloud and observing the particle trajectories in a co-rotating frame, which allows reaching effective magnetic fields up to 3000 Tesla. The experimental results confirm the predictions of the simulations: (i) super-diffusive behavior is found at intermediate time-scales and (ii) the dependence of the self-diffusion coefficient on the magnetic field is well reproduced., Comment: accepted by Physical Review E

Spontaneous formation of spinning pairs of particles, or torsions was studied in a single-layer complex plasma crystal by reducing the discharge power at constant neutral gas pressure. At higher gas pressures, torsions spontaneously formed below a certain power threshold. Further reduction of the discharge power led to the formation of multiple torsions. However, at lower gas pressures the torsion formation was preceded by the mode-coupling instability (MCI). The crystal dynamics were studied with the help of the fluctuation spectra of crystal particles’ in-plane velocities. Surprisingly, the spectra of the crystal with torsions and MCI are rather similar and contain “hot spots” at similar locations on the (k, ω) plane, despite very different appearances of the respective particle trajectories. The torsion rotation speed was close (slightly below) to the maximum frequency of the in-plane compressional mode. When multiple torsions formed, their rotation speeds were distributed in a narrow range slightly below the maximum frequency.

This paper presents a case study of an existing water pipeline with five pumping stations each equipped with five pumps. In order to study the pipeline behavior prior to putting the system into operation, several transient simulations for different scenarios were developed. Results revealed that the most serious situation occurred when a simultaneous failure of the five pumps occur at each station caused by power cut, producing negative pressure waves because the system for control of hydraulic transients of the pipeline was insufficient to suppress downsurge pressures, due to the moment of inertia of all the pumps being erroneously considered during the design stage. The necessity to start supplying water to the population led to attempt an unconventional form of protecting the line against low pressures. The solution was to operate two of the five pumps per plant, and permit air to enter through combination air valves located along the pipeline. Air entrained formed pockets that remained stationary at the air valves locations, acting as air cushions that absorbed the energy of transient pressure waves. Computational simulations were conducted considering that two pumps are in operation at each plant and suddenly these fail simultaneously caused by power failure. The program was verified by comparing the calculated results with those registered during field pressure measurements. It was noticed that the surge modelling results are in good agreement with the measured data, furthermore, these show the air pockets in combination with existing devices for transient control protect the system adequately, avoiding potential damage to the pipeline.

In this experiment, falling particle trajectories within and without a glass box placed on the lower electrode in a Gaseous Electronics Conference reference cell are recorded and analyzed, and the electrostatic forces exerted on the dust particles are measured and compared. Experimental results show that, for particles falling in a complex plasma with no glass box, only a single force balance point (i.e., the position where the gravitational force is balanced by the electrostatic force) exists in the vertical direction while, for particles falling inside a glass box, this force balance spans an extended vertical range.

Using the “rotodust” experimental setup [1] at the Hypervelocity Impacts and Dusty Plasmas Lab (HIDPL) of the Center for Astrophysics, Space Physics, and Engineering Research (CASPER) at Baylor University we have realized effective magnetization of single layer dusty plasma systems in the strongly coupled state up to thousands of Teslas of magnetic induction. The self-diffusion in these ensembles of 300 to 400 particles was derived by measuring the cage correlation function [2] in the central region and utilizing the recently found connection between the variation of particle environments (cages) and the diffusion coefficient [3]. Systems parameters (Γ coupling and κ screening in the Yukawa OCP model) were determined using the pair distribution and the velocity autocorrelation functions [4].

Dust particles often form vertical chains due to the influence of the wakefield produced by streaming ions in the plasma sheath produced within an experimental dusty plasma. These particle chains are proving to be a unique diagnostic tool for investigating the physics behind the basic properties of the ion wakefield in the plasma sheath. In this paper, an experimental method is presented for investigating the wakefield employing a new oscillation technique designed to perturb a two-particle vertical chain. Damped attenuated oscillations are generated via an external dc bias on the lower electrode. A fast Fourier transform is used to produce a spectrum of the oscillation data collected, and a center of mass oscillation is identified.

The exoplanet Kepler 22b

Background To evaluate arteriovenous graft patency when failing grafts are treated with Viabahn covered stents vs percutaneous angioplasty (PTA) alone. Methods A retrospective review of all patients that underwent endovascular interventions for failing grafts at a single institution between January 2010 and July 2013 was performed. Forty-four patients were identified who were treated with PTA alone (11) and with Viabahn stent grafts (33) for stenoses in the venous to graft anastomoses. Patient demographics, procedural success, and intraoperative complications were recorded as well as graft patency at 3, 6, and 12 months. Graft patency was reviewed and compared with PTA alone. Results There was no statistically significant difference between the 2 groups regarding gender, frequency of diabetes, hypertension, coronary artery disease, or peripheral arterial disease. Primary technical success defined as residual stenosis 10% or less was achieved in 100% of the cases. Follow-up was determined by flow velocities during dialysis and ultrasound imaging in the vascular laboratory. At 12 months 87.8% (29/33) grafts with stents were functional vs 36.4% (4/11) of those with PTA alone. Primary patency of the stent group was 61%, 52%, and 42% at 3, 6, and 12 months respectively vs the PTA group 64%, 45%, and 9%. Conclusions Grafts treated with Viabahn covered stents for outflow stenosis have a superior patency to PTA alone, 12 months after treatment; although earlier post treatment results are comparable.

In this paper we construct effective invariants for braid monodromy of affine curves. We also prove that, for some curves, braid monodromy determines their topology. We apply this result to find a pair of curves with conjugate equations in a number field but which do not admit any orientation-preserving homeomorphism.

Small quasi-two-dimensional (2D) dust clusters consisting of three to eleven particles are formed in an argon plasma under varying rf power. Their normal modes are investigated through their mode spectra obtained from tracking thermal motion of the particles. Detailed coupling patterns between their horizontal and vertical modes are detected for particle numbers up to seven and discrete instabilities are found for dust clusters with particle number greater than nine, as predicted in previous theory on ion-flow induced mode coupling in small clusters. The instabilities are proven to be induced by resonance between coupled horizontal and vertical normal modes., Comment: 9 pages, 4 figures

Understanding the agglomeration of dust particles in complex plasmas requires a knowledge of the basic properties such as the net electrostatic charge and dipole moment of the dust. In this study, dust aggregates are formed from gold coated mono-disperse spherical melamine-formaldehyde monomers in a radio-frequency (rf) argon discharge plasma. The behavior of observed dust aggregates is analyzed both by studying the particle trajectories and by employing computer models examining 3D structures of aggregates and their interactions and rotations as induced by torques arising from their dipole moments. These allow the basic characteristics of the dust aggregates, such as the electrostatic charge and dipole moment, to be determined. It is shown that the experimental results support the predicted values from computer models for aggregates in these environments., 6 pages, 7 figures

We report complex plasma experiments, assisted by numerical simulations, providing an alternative qualitative link between the macroscopic response of polycrystalline solid matter to small shearing forces and the possible underlying microscopic processes. In the stationary creep regime we have determined the exponents of the shear rate dependence of the shear stress and defect density, being $\alpha = 1.15 \pm 0.1$ and $\beta = 2.4 \pm 0.4$, respectively. We show that the formation and rapid glide motion of dislocation pairs in the lattice are dominant processes., Comment: 5 pages, 5 figures accepted by PRL

Using dust grains as probes in gas discharge plasma is a very promising, but at the same time very challenging method, as the individual external control of dust grains has to be solved. We propose and demonstrate the applicability of the RotoDust experiment, where the well controlled centrifugal force is balanced by the horizontal confinement field in plane electrode argon radio frequency gas discharges. We have reached a resolution of 0.1 V/cm for the electric field. This technique is used to verify numerical simulations and to map symmetry properties of the confinement in dusty plasma experiments using a glass box., accepted by Plasma Sources Science and Technology

Objetivo. Determinar la relacion de los valores hematologicos maternos y neonatales en casos de reservas maternas de hierro bajas, moderadas y normales. Material y metodos. Diseno transversal en el que se incluyo a 163 mujeres embarazadas y sus neonatos de termino, derechohabientes del Hospital de Ginecologia y Obstetricia numero 15 del Instituto Mexicano del Seguro Social (IMSS) en Chihuahua, Chih., Mexico. Se analizaron antecedentes maternos. Se determinaron niveles de hemoglobina, hematocrito y ferritina serica en muestras maternas y de cordon umbilical. Se definieron reservas de hierro maternas de acuerdo a ferritina (µg /l): bajas o = 20.1. Se utilizo la prueba de Kruskal Wallis para establecer diferencias entre grupos, ji cuadrada para diferencia de proporciones y r de Pearson para establecer la relacion entre reservas de hierro maternas y del recien nacido. Resultados. Se determino una debil correlacion entre la ferritina materna y neonatal r=0.14 (p=0.07). Las medias geometricas de ferritina neonatal respecto a las reservas maternas bajas, moderadas y normales fue de 4.77, 4.85 y 5.02, respectivamente (p=0.12). Las reservas de hierro maternas se modificaron con el suplemento de hierro (p=0.01). Conclusiones. Las reservas de hierro en el recien nacido estan en estrecha relacion con las maternas. Las mujeres que toman suplementos con hierro durante la gestacion tienen reservas mayores al final del embarazo. El texto completo en ingles de este articulo esta disponible en: http://www.insp.mx/salud/index.html

Dust aggregates are formed in a laboratory plasma as monodisperse spheres are accelerated in a self-excited dust density wave. The asymmetric charge on the aggregates causes them to rotate as they interact with the sheath electric field or other aggregates The charge and dipole moment can be estimated and compared to numerical models. "Dust molecules", where two particles are electrostatically bound but not physically touching, are also observed.

Fistula-in-ano is an abnormal connection between the inner surface of the anal canal and the perineal skin.Between 2001 and 2010, seventeen patients with fistula-in-ano were surgically managed by a single surgeon within the University Pediatric Hospital and HIMA-San Pablo Hospital.There were 16 males and 1 female. The mean age at the time of operation was four years divided between infants (71%) and school children (29%). Fistulas were located on the midline right side in 5 patients, midline left side in 3 patients, midline bilaterally in 2 patients, in the anterior raphe in 4 patients and in the posterior raphe in 3 patients. Two patients of the infant group and two patients of the children group developed a perianal abscesses prior to the occurrence of fistula. All patients were managed with either fistulotomy or fistulectomy with six of them combined with Seton placement. There were no recurrence or complications.Fistulotomy is still considered the standard of care.

Wandering spleen is a rare birth defect characterized by absence or weakness of one or more of the ligaments that hold the spleen in its normal position. In this report we present the case of a 6-year-old girl admitted with diffuse abdominal pain, fever and emesis. Ultrasound and CT scan revealed the spleen was not found in its normal anatomical position. An enlarged spleen was identified displaced anteriorly and inferiorly at the L3 to L5-S1 level. Doppler ultrasonography of the splenic vessels revealed no blood flow consistent with infarction. Patient was taken to the operation room for a laparoscopic splenectomy. Treatment of choice for splenoptosis is surgery, either splenopexy or splenectomy. Decision to perform splenopexy or splenectomy depends on the viability of the spleen after detorsion. If the spleen appears infarcted, a splenectomy should be performed. Splenopexy is a reasonable option when the spleen appears viable after detorsion.

This note provides a negative answer to the following question of A. H. Durfee [Invent. Math. 28 (1975), 231–241; ]: Is it true for arbitrary polynomials F(x,y,z) having an isolated singularity at the origin that the local monodromy is of finite order if and only if a resolution of F(x,y,z)=0 contains no cycles? Here "the monodromy'' means the action on the cohomology of the Milnor fiber of F corresponding to the degeneration F(x,y,z)=t. The authors consider the following example: F(x,y,z)=(xz−y2)3−((y−x)x2)2+z6. They calculate the graph of the resolution (which is a tree) and invariant polynomials of the monodromy (showing the presence of Jordan blocks of a size greater than 1). The key point in these calculations is that this singularity belongs to the class of superisolated (SIS) surface singularities which was studied in detail by the first named author [Mem. Amer. Math. Soc. 109 (1994), no. 525, x+84 pp.;]. SISs are the singularities of the form F(x,y,z)=f(x,y,z)+lN, where l is a generic linear form, N is a sufficiently large integer and f(x,y,z)=0 is a projective plane algebraic curve, the cone over which is the tangent cone of the singularity F(x,y,z). The main step in detecting that the order of the monodromy of a SIS is infinite is the calculation of the Alexander polynomial [A. S. Libgober, Duke Math. J. 49 (1982), no. 4, 833–851;] of the plane curve f(x,y,z)=0. In the authors' example, the plane sextic (xz−y2)3−((y−x)x2)2 has two singularities with local types u3=v10 and u2=v3 respectively and has as its Alexander polynomial t2−t+1. The latter yields that the monodromy of F has an infinite order. The paper is concluded with a series of other interesting observations on the relation between the topology of resolution and monodromy of SIS singularities.

We report a series of complex (dusty) plasma experiments, aimed at the study of the detailed time evolution of the re-crystallisation process following a rapid quench of a two dimensional dust liquid. The experiments were accompanied by large-scale (million particle) molecular dynamics simulations, assuming Yukawa type inter-particle interaction. Both experiment and simulation show a $\propto t^\alpha$ (power law) dependence of the linear crystallite domain size as measured by the bond-order correlation length, translational correlation length, dislocation (defect) density, and a direct size measurement algorithm. The results show two stages of order formation: on short time-scales individual particle motion dominates; this is a fast process characterized by $\alpha=0.93\pm0.1$. At longer time-scales, small crystallites undergo collective rearrangement, merging into bigger ones, resulting in a smaller exponent $\alpha=0.38\pm0.06$., Comment: 4 pages, 3 figures. Submitted to PRL

Employing an attenuated oscillation method, the anisotropic interaction force between two vertically aligned dust particles located in the sheath of a complex plasma was measured experimentally based on a linear approximation to the interaction force. Experimental data shows that although both particles experience a repulsive interaction force, the upper particle experiences a stronger magnitude force than does the lower. This result can be explained by the ion wakefield since the lower particle resides within the ion wakefield generated by the streaming ions passing through the sheath and around the upper particle.

Summary form only given. Complex plasmas are known to exist in a variety of natural and laboratory environments. Within an experimentally produced complex plasma such as that found in a GEC rf reference cell in a laboratory, it has been shown that dust particles often form two-, three-, or even longer particle chains, vertically aligned within the sheath. Of these, the two-particle chain remains the simplest structure. The interparticle (interlayer) interaction between upper and lower particles is of great interest and not yet completely understood. This paper discusses this interaction, providing data produced by perturbing such particle chains employing a modulated DC bias on the lower (powered) electrode. Using upper and lower particles having different masses (resulting in different charges), the resonant frequencies of each will be examined and analyzed.