We examine the evolution of an inhomogeneous mixture of non-relativistic pressureless cold dark matter (CDM), coupled to dark energy (DE) characterised by the equation of state parameter
w
<
-
1
/
3
..., with the interaction term proportional to the DE density. This coupled mixture is the source of a spherically symmetric Lemaître–Tolman–Bondi (LTB) metric admitting an asymptotic Friedman–Lemaître–Robertson–Walker (FLRW) background. Einstein’s equations reduce to a 5-dimensional autonomous dynamical system involving quasi–local variables related to suitable averages of covariant scalars and their fluctuations. The phase space evolution around the critical points (past/future attractors and five saddles) is examined in detail. For all parameter values and both directions of energy flow (CDM to DE and DE to CDM) the phase space trajectories are compatible with a physically plausible early cosmic times behaviour near the past attractor. This result compares favourably with mixtures with interaction driven by the CDM density, whose past evolution is unphysical for DE to CDM energy flow. Numerical examples are provided describing the evolution of an initial profile that can be associated with idealised structure formation scenarios.
The clam Ameghynomia antiqua is a highly important resource for fisheries due to its high catches volume. It is the bivalve mollusc with the highest fisheries landings from natural beds on the ...Pacific coast of southern South America; however, studies of the reproductive conditions of this species are scarce and date back many years. The object of the present work was to evaluate the reproductive characteristics of the species, analysing its gametogenic and gonadal cycle, and reproductive indices, in fishery locations that present the natural beds with the highest fisheries catches, as well as parasite loads in the species. The gonads of the individuals were sampled monthly over a year and classified into one of three states called: "in development", "ripe" and "spawned". Synchrony between the sexes was observed in the indicators of the Gonadosomatic Index and Condition Index in each of the locations, although no synchrony was observed between locations. In the gametogenic cycle, the "ripe" state was observed in females in spring-summer, followed by rapid recovery to new development of the gonads; in males the "ripe" state was observed throughout the year. It was observed that males entered the "spawned" state one month ahead of females. The presence of digenean parasites in the state of metacercariae was detected in the gonads and mantle. No significant differences were found in the prevalence or intensity of infection when analysed by sex and month. The metacercariae were identified, by sequencing of three DNA regions, as belonging to the clade shared by species of the genus Parvatrema and close to the Gymnophalloides; both these genera belong to the family Gymnophallidae of the superclass Digenea. Infection was observed to reduce the gonadal tissue, in some cases causing castration. This is the first record of the presence of these parasites of A. antiqua, with genetic identification at genus level. These results are relevant for act proper management of this resource, which is important for fishing.
The quasi-local scalar variables approach is applied to a spherically symmetric inhomogeneous Lemaître–Tolman–Bondi metric containing a mixture of non-relativistic cold dark matter and coupled dark ...energy with constant equation of state. The quasi-local coupling term considered is proportional to the quasi-local cold dark matter energy density and a quasi-local Hubble factor-like scalar via a coupling constant
α
. The autonomous numerical system obtained from the evolution equations is classified for different choices of the free parameters: the adiabatic constant of the dark energy
w
and
α
. The presence of a past attractor in a non-physical region of the energy densities phase-space of the system makes the coupling term non physical when the energy flows from the matter to the dark energy in order to avoid negative values of the dark energy density in the past. On the other hand, if the energy flux goes from dark energy to dark matter, the past attractor lies in a physical region. The system is also numerically solved for some interesting initial profiles leading to different configurations: an ever expanding mixture, a scenario where the dark energy is completely consumed by the non-relativistic matter by means of the coupling term, a scenario where the dark energy disappears in the inner layers while the outer layers expand as a mixture of both sources, and, finally, a structure formation toy model scenario, where the inner shells containing the mixture collapse while the outer shells expand.
FGFR3 and Tp53 mutations have been proposed as defining two alternative pathways in the pathogenesis of transitional bladder cancer. FGFR3 mutations are associated with low-grade tumors and a ...favorable prognosis. Tp53 alterations are associated with advanced tumors and, possibly, with a poor prognosis. We focus here on the subgroup of T1G3 superficial tumors because they are a major clinical challenge. Patients (n = 119) were identified from a prospective study of 1,356 cases. Mutations in FGFR3 (exons 7, 10, and 15) and Tp53 (exons 4-9) were analyzed using PCR and direct sequencing. All cases were followed for recurrence and death. Survival was analyzed using Kaplan-Meier curves and multivariable Cox regression. FGFR3 mutations were detected in 20 (16.8%) tumors; 100 mutations in Tp53 were found in tumors from 78 (65.5%) cases. Multiple alterations in Tp53 were present in 19 tumors (16%). Inactivating mutations were present in 58% of tumors. The combined mutation distribution (FGFR3/Tp53) was: wt/wt (34.5%), mut/wt (7.6%), wt/mut (48.7%), and mut/mut (9.2%), indicating that the presence of either mutation did not depend on the other (P value = 0.767). FGFR3 and Tp53 mutations were not associated with clinicopathologic characteristics of patients and did not predict, alone or in combination, recurrence or survival. Taking the risk of the wt/wt group as reference, the mutation-associated risks of cancer-specific mortality were: mut/wt 1.42 (0.15-13.75), wt/mut 0.67 (0.19-2.31), mut/mut 1.62 (0.27-9.59). These molecular features support the notion that T1G3 tumors are at the crossroads of the two main molecular pathways proposed for bladder cancer development and progression.
Venereal syphilis is a multi-stage, sexually transmitted disease caused by the spirochetal bacterium Treponema pallidum (Tp). Herein we describe a cohort of 57 patients (age 18-68 years) with ...secondary syphilis (SS) identified through a network of public sector primary health care providers in Cali, Colombia. To be eligible for participation, study subjects were required to have cutaneous lesions consistent with SS, a reactive Rapid Plasma Reagin test (RPR-titer > or = 1 : 4), and a confirmatory treponemal test (Fluorescent Treponemal Antibody Absorption test- FTA-ABS). Most subjects enrolled were women (64.9%), predominantly Afro-Colombian (38.6%) or mestizo (56.1%), and all were of low socio-economic status. Three (5.3%) subjects were newly diagnosed with HIV infection at study entry. The duration of signs and symptoms in most patients (53.6%) was less than 30 days; however, some patients reported being symptomatic for several months (range 5-240 days). The typical palmar and plantar exanthem of SS was the most common dermal manifestation (63%), followed by diffuse hypo- or hyperpigmented macules and papules on the trunk, abdomen and extremities. Three patients had patchy alopecia. Whole blood (WB) samples and punch biopsy material from a subset of SS patients were assayed for the presence of Tp DNA polymerase I gene (polA) target by real-time qualitative and quantitative PCR methods. Twelve (46%) of the 26 WB samples studied had quantifiable Tp DNA (ranging between 194.9 and 1954.2 Tp polA copies/ml blood) and seven (64%) were positive when WB DNA was extracted within 24 hours of collection. Tp DNA was also present in 8/12 (66%) skin biopsies available for testing. Strain typing analysis was attempted in all skin and WB samples with detectable Tp DNA. Using arp repeat size analysis and tpr RFLP patterns four different strain types were identified (14d, 16d, 13d and 22a). None of the WB samples had sufficient DNA for typing. The clinical and microbiologic observations presented herein, together with recent Cali syphilis seroprevalence data, provide additional evidence that venereal syphilis is highly endemic in this region of Colombia, thus underscoring the need for health care providers in the region to be acutely aware of the clinical manifestations of SS. This study also provides, for the first time, quantitative evidence that a significant proportion of untreated SS patients have substantial numbers of circulating spirochetes. How Tp is able to persist in the blood and skin of SS patients, despite the known presence of circulating treponemal opsonizing antibodies and the robust pro-inflammatory cellular immune responses characteristic of this stage of the disease, is not fully understood and requires further study.
Se estudió la morfología de las escamas situadas en ambas líneas laterales de D. eleginoides y fueron comparadas con las escamas corporales obtenidas de 12 sectores diferentes a lo largo de los ejes ...antero-posterior y dorso-ventral del tronco. Las escamas de ambas líneas son del tipo cicloídeas y ovaladas; están constituidas por una placa de la escama, un tubo central con una abertura anterior (ausente en algunas escamas del sector medio del tronco) y otra posterior. El análisis morfológico no mostró diferencias entre las escamas de ambas líneas; sin embargo, las escamas corporales se diferencian de las escamas de la línea lateral por la ausencia del tubo central. La mayoría de las escamas del sector anterior del cuerpo son cicloídeas y sólo algunas son del tipo ctenoídeas; mientras que en la zona media y posterior es característica la presencia de ambos tipos de escamas en el lado derecho e izquierdo del cuerpo. Los resultados obtenidos entregan nuevos antecedentes morfológicos básicos tanto para las escamas presentes en ambas líneas laterales como las corporales. Es recomendable en el caso de las escamas de las líneas laterales continuar con estudios histológicos para determinar la conexión nerviosa entre ambas y obtener así una visión más completa del sistema mecanosensorial de D. eleginoides.
Ivermectin is widely prescribed as a potential treatment for COVID-19 despite uncertainty about its clinical benefit.
To determine whether ivermectin is an efficacious treatment for mild COVID-19.
...Double-blind, randomized trial conducted at a single site in Cali, Colombia. Potential study participants were identified by simple random sampling from the state's health department electronic database of patients with symptomatic, laboratory-confirmed COVID-19 during the study period. A total of 476 adult patients with mild disease and symptoms for 7 days or fewer (at home or hospitalized) were enrolled between July 15 and November 30, 2020, and followed up through December 21, 2020.
Patients were randomized to receive ivermectin, 300 μg/kg of body weight per day for 5 days (n = 200) or placebo (n = 200).
Primary outcome was time to resolution of symptoms within a 21-day follow-up period. Solicited adverse events and serious adverse events were also collected.
Among 400 patients who were randomized in the primary analysis population (median age, 37 years interquartile range {IQR}, 29-48; 231 women 58%), 398 (99.5%) completed the trial. The median time to resolution of symptoms was 10 days (IQR, 9-13) in the ivermectin group compared with 12 days (IQR, 9-13) in the placebo group (hazard ratio for resolution of symptoms, 1.07 95% CI, 0.87 to 1.32; P = .53 by log-rank test). By day 21, 82% in the ivermectin group and 79% in the placebo group had resolved symptoms. The most common solicited adverse event was headache, reported by 104 patients (52%) given ivermectin and 111 (56%) who received placebo. The most common serious adverse event was multiorgan failure, occurring in 4 patients (2 in each group).
Among adults with mild COVID-19, a 5-day course of ivermectin, compared with placebo, did not significantly improve the time to resolution of symptoms. The findings do not support the use of ivermectin for treatment of mild COVID-19, although larger trials may be needed to understand the effects of ivermectin on other clinically relevant outcomes.
ClinicalTrials.gov Identifier: NCT04405843.
PDF
