1,464 research outputs found
Quantum density anomaly in optically trapped ultracold gases
We show that the Bose-Hubbard Model exhibits an increase in density with
temperature at fixed pressure in the regular fluid regime and in the superfluid
phase. The anomaly at the Bose-Einstein condensate is the first density anomaly
observed in a quantum state. We propose that the mechanism underlying both the
normal phase and the superfluid phase anomalies is related to zero point
entropies and ground state phase transitions. A connection with the typical
experimental scales and setups is also addressed. This key finding opens a new
pathway for theoretical and experimental studies of water-like anomalies in the
area of ultracold quantum gases
Deep-sea benthic foraminifera of Campos Basin, SE Brazil: distribution, taxonomy and response to climatic and eustatic variations in the late Quaternary
Abstrac
Effects of dual-task interventions on gait performance of patients with parkinson’s disease: a systematic review
OBJECTIVE: Parkinson’s disease is characterized by motor and non-motor symptoms that impair patients’ gait performance, especially while performing dual/concurrent tasks. These deficits impair patients’ daily function, because dual-tasking is a crucial ability in terms of everyday living. The aim of this study was to systematically review the effects of dual task interventions on gait performance of patients with Parkinson’s disease.
METHOD: Studies were retrieved from MEDLINE/PubMed, LILACS and SciELO. We used the PICOS strategy to determine eligibility criteria. The search strategy included an advanced search on the included databases, using the following search query: “Parkinson’s Disease” AND “Double Task” OR “Concurrent Tasks” OR “Gait” AND “Walk”. Study selection was carried out by two independent researchers and a third one was called when consensus was needed.
RESULTS: A total of 188 articles were identified: 169 articles from Medline/PubMed, 10 articles in SciELO, 8 articles in LILACS and 1 item from manual searches. A total of 56 articles were analyzed regarding the eligibility and exclusion criteria based on full text. A final total of 7 studies were included in the systematic review.
CONCLUSION: The different types of dual-task interventions reported (dance, sound stimuli, visual and somatosensory) were associated to improvements in several gait performance indicators of Parkinson’s disease patients, including gait speed, stride time and length, cadence and step length. External stimuli seem to play a critical role on specific training effects on dual-task gait performance.info:eu-repo/semantics/publishedVersio
Liquid crystal phase and waterlike anomalies in a core-softened shoulder-dumbbells system
Using molecular dynamics we investigate the thermodynamics, dynamics and
structure of 250 diatomic molecules interacting by a core-softened potential.
This system exhibits thermodynamics, dynamics and structural anomalies: a
maximum in density-temperature plane at constante pressure and maximum and
minimum points in the diffusivity and translational order parameter against
density at constant temperature. Starting with very dense systems and
decreasing density the mobility at low temperatures first increases, reach a
maximum, then decreases, reach a minimum and finally increases. In the
pressure-temperature phase diagram the line of maximum translational order
parameter is located outside the line of diffusivity extrema that is enclosing
the temperature of maximum density line. We compare our results with the
monomeric system showing that the anisotropy due to the dumbbell leads to a
much larger solid phase and to the appearance of a liquid crystal phase. the
double ranged thermodynamic and dynamic anomalies.Comment: 14 pages, 5 figure
Waterlike density anomaly in fermions
In this work we explore the one-dimensional extended Hubbard model as a fluid
system modelling liquid phases of different densities. This model naturally
displays two length scales of interaction, which are connected with waterlike
anomalies. We analyze the density anomaly as a function of the model
parameters, namely the hopping, on-site and first neighbor interactions. We
show that this anomaly is present for a wide range of model parameters and is
connected to a ground-state liquid-liquid critical point.Comment: 15 pages, 9 figure
Produção e tamanho de grãos de café (Coffea arabica L.) cv Catuaà em diferentes arranjos populacionais e disponibilidades de água no solo
The purpose of this research was to evaluate the effect of drip irrigation under different population arrangements on the phytometric features, coffee productivity and bean size classification according to sieve retention. The experiment with Coffea arabica L. cv CatuaĂ was carried out in Mococa, SĂŁo Paulo, Brazil. The experimental design was a 6 x 2 factorial scheme in randomized blocks, with four replications. The six densities of plantation were E1 (1.60 x 0.50 m); E2 (1.60 x 0.75 m); E3 (1.60 x 1.00 m); E4 (3.20 x 0.50 m); E5 (3.20 x 0.75 m) and E6 (3.20 x 1.00 m), which were divided according to the availability of water (irrigated - I - or non-irrigated - NI - groups). Data were submitted to analysis of variance and averages compared by Tukey test at 1 and 5% of probability. Descriptive analysis of coffee beans according to sieve classification was performed. Irrigation promoted an increase in plant height, crown diameter and production of processed coffee when compared with the NI group. Interaction between population arrangement and irrigation was observed, with an increase in production and crown diameter as the spacing was decreased. Therefore, irrigation provided significant increase in coffee bean size.O objetivo deste estudo foi avaliar o efeito da irrigação por gotejamento em diferentes arranjos populacionais nas caracterĂsticas fitomĂ©tricas, na produtividade de cafĂ© beneficiado e na classificação dos grĂŁos por tamanho, de acordo com a retenção em peneiras. O experimento foi conduzido em Mococa-SP, com o cafeeiro Coffea arabica L. cv CatuaĂ. Adotou-se o delineamento experimental em blocos ao acaso, em esquema fatorial 6 x 2, com quatro repetições, sendo seis densidades de plantio: E1 (1,60 x 0,50 m); E2 (1,60 x 0,75 m); E3 (1,60 x 1,00 m); E4 (3,20 x 0,50 m); E5 (3,20 x 0,75 m), e E6 (3,20 x 1,00 m), divididas em irrigadas (I) e nĂŁo irrigadas (NI). As variáveis foram submetidas Ă análise de variância, e as mĂ©dias, comparadas entre si pelo teste de Tukey, a 1 e 5% de probabilidade. Foi realizada análise descritiva dos grĂŁos nas classes de peneiras. A irrigação promoveu aumento na altura das plantas, maior diâmetro de copa e produção de cafĂ© beneficiado quando comparado ao sistema nĂŁo irrigado. Houve interação entre arranjo populacional e irrigação, com aumento na produção e no diâmetro da copa, conforme o espaçamento era reduzido. O uso da irrigação propiciou aumentos significativos na granulometria dos grĂŁos de cafĂ©.14515
Water regimes and bean cultivar effects on the soil porous system characteristics
Bean (Phaseolus vulgaris L.) is a crop of great economic and social impacts in Brazil. This crop is extremely appreciated by the Brazilian population and an important source of protein. Usually the small farmers are responsible by the largest production of the bean in Brazil. This work deals with the analysis of the effect of different water regimes (35, 28, 21 and 14%) on the porous system of a soil cropped with two distinct cultivars (Campos Gerais and Tuiuiú). Soil water retention curve (SWRC) and its derivative were utilized with the aim of investigating the changes in the porous system. Pore size distribution was also evaluated. The experiment was carried out at a greenhouse and the soil water content for the different water regimes was monitored by means of a TDR. Four undisturbed samples were collected from each wooden bed (eight) for the physic-hydrical characterization. Discrepancies in the SWRC were noticed for the region of small pressure heads. Differences were not observed between bean cultivars to SWRC. However, the water capacity function was sensitive to show differences in the soil porous system due to the treatments and cultivars. The lowest water regimes promoted the highest volume of fissures (big pores >250 µm) and, consequently, the highest ones had the largest volume of storage pores (<25 µm)
Two New Species of \u3ci\u3eHermeuptychia\u3c/i\u3e from North America and Three Neotype Designations (Nymphalidae: Satyrinae)
Abstract
Two new species of Hermeuptychia Forster, 1964 are described. Hermeuptychia sinuosa Grishin, sp. n. (type locality Guatemala: El Progreso, Morazán) is an isolated member of the genus that does not readily fit into known species groups, as suggested by its distinct male and female genitalia and COI DNA barcode sequences. It is distinguished from its congeners by prominently wavy submarginal lines, rounder wings and distinctive genitalia, and can typically be identified by a white dot, instead of an eyespot, near the ventral hindwing apex. Hermeuptychia occidentalis Grishin, sp. n. (type locality Mexico: Guerrero, Acapulco) belongs to the Hermeuptychia sosybius group as indicated by the presence of androconia on the dorsal surface of the wings, genitalia and COI DNA barcodes, and in addition to DNA characters, differs from its relatives in the shape of the uncus and female genitalia. Neotypes of Oreas strigata canthe Hübner, [1811] (type locality Suriname: Gelderland, Suriname River), Megisto acmenis Hübner, 1823 (type locality Argentina: Buenos Aires), and Satyrus cantheus Godart, [1824] (type locality USA: Florida, Pinellas County, St. Petersburg) and lectotype of Euptychia celmis var. bonaërensis [sic] Burmeister, 1878 (type locality Argentina: Buenos Aires) are designated. These designations establish Hermeuptychia canthe as a valid species widely distributed in South America from Colombia to Bolivia and southeast Brazil, Euptychia celmis var. bonaërensis [sic] Burmeister, 1878 as a junior objective synonym of Yphthimoides acmenis, and S. cantheus as a junior subjective synonym of Hermeuptychia sosybius (Fabricius, 1793). Papilio camerta Cramer, 1780 is treated as nomen dubium requiring further studies to determine an identity that is consistent with the original description, as it may be conspecific with Paryphthimoides poltys (Prittwitz, 1865) instead of being a Hermeuptychia species as currently assumed.
Resumen
Se describe dos nuevas especies de Hermeuptychia Forster, 1964. Hermeuptychia sinuosa Grishin, sp. n. (localidad tipo Guatemala: El Progreso, Morazán), es un componente aislado del gĂ©nero que no encaja fácilmente en los grupos de especies conocidas, como lo indica su distintiva genitalia masculina y femenina y las secuencias de ADN del cĂłdigo de barras COI. Se distingue de sus congĂ©neres por tener lĂneas submarginales prominentemente onduladas, alas más redondas y genitales diferentes, y se puede identificar tĂpicamente por un punto blanco, en lugar de una mancha ocular, cerca del ápice ventral del ala anterior. Hermeuptychia occidentalis Grishin, sp. n. (localidad tipo MĂ©xico: Guerrero, Acapulco) pertenece al grupo de Hermeuptychia sosybius como lo indica la presencia de androconia en las alas anteriores, la estructura genital y secuencias de ADN de la regiĂłn del cĂłdigo de barras COI, y además de caracteres del ADN, se diferencia de sus parientes en la forma del uncus y la genitalia femenina. Se designa neotipos para Oreas strigata canthe HĂĽbner, [1811] (localidad tipo Surinam: Gelderland, RĂo Surinam), Megisto acmenis HĂĽbner, 1823 (localidad tipo Argentina: Buenos Aires), y Satyrus cantheus Godart, [1824] (localidad tipo Estados Unidos: Florida, Pinellas County, St. Petersburg), y el lectotipo de Euptychia celmis var. bonaĂ«rensis [sic] Burmeister, 1878 (localidad tipo Argentina: Buenos Aires). Estas designaciones establecen a Hermeuptychia canthe como una especie válida ampliamente distribuida en AmĂ©rica del Sur desde Colombia hasta Bolivia y el sureste de Brasil, a Euptychia celmis var. bonaĂ«rensis [sic] Burmeister, 1878 como sinĂłnimo objetivo más reciente de Yphthimoides acmenis, y a S. cantheus como sinĂłnimo subjetivo más reciente de Hermeuptychia sosybius (Fabricius, 1793). Papilio camerta Cramer, 1780 es tratado como un nomen dubium requiriendo más estudios para determinar una identidad que sea consistente con la descripciĂłn original, ya que puede ser coespecĂfica con Paryphthimoides poltys (Prittwitz, 1865) en lugar de ser una especie de Hermeuptychia como se asume actualmente.
COI = c oxidase subunit
Aerodynamic analysis of human walking, running and sprinting by numerical simulations
The drag in walking, running, and sprinting locomotion can be assessed by analytical procedures and experimental techniques. However, assessing the drag variations by these three main locomotion’s (i.e., walking, running, and sprinting) were not found using computational fluid dynamics. (CFD). Thus, the aim of this study was two-fold: (1) to assess the aerodynamics of human walking, running, and sprinting by CFD technique; 2) compare such aerodynamic characteristics between walking and running. Three 3D models were produced depicting the walking, running, and sprinting locomotion techniques, converted to computer aided design models and meshed. The drag varied with 4 locomotion type. Walking had the lowest drag, followed-up by running and then sprinting. At the same velocities, the drag was larger in walking than in running and increased with velocity. In conclusion, drag varied with locomotion type. Walking had the lowest drag, followed-up by running and then sprinting. At the same velocities, the drag was larger in walking than in running and increased with velocity.This project was founded by the Portuguese Foundation for Science and Technology, I.P. (project UIDB04045/2020)info:eu-repo/semantics/publishedVersio
Effect of an Er,Cr:YSGG laser on the surface of implants: a descriptive comparative study of 3 different tips and pulse energies
Peri-implant diseases are one of the main complications of dental implants. There are no well-established guidelines regarding laser parameters for implant decontamination. The aim was to compare two different settings of irradiation of the Er,Cr:YSGG laser on dental implants regarding surface alterations and determine the best settings for less damage on the surface. An in vitro study was performed and 30 areas of dental implants were irradiated with two different regimes of energy per pulse 50 and 84 mJ (1.5 W/30 Hz and 2.5 W/30 Hz). A total of 30 sites of implants were irradiated with three different tips (10 surfaces per tip): conical (RTF3-17 mm), side firing (SFT8-18 mm) and cylindrical (MGG6-6 mm). The following descriptive classification on surface damage was employed: no damage (class A), minimal effects (class B), metal fall with melting (class C), and destruction with carbonization (class D). The assessment was made through a descriptive scanning electron microscope (SEM) analysis. Side firing and conical tips at 50 mJ were classified as class A. Side firing at 84 mJ and cylindrical tips 50 mJ and 84 mJ were classified as class B. Finally, class C defects were found in the areas where the conical tip was used at 84 mJ. Side firing and conical tips at 50 mJ do not seem to damage the implant surface
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