Blazar spectral variability as explained by a twisted inhomogeneous jet.

Blazars are active galactic nuclei, which are powerful sources of radiation whose central engine is located in the core of the host galaxy. Blazar emission is dominated by non-thermal radiation from a jet that moves relativistically towards us, and therefore undergoes Doppler beaming. This beaming causes flux enhancement and contraction of the variability timescales, so that most blazars appear as luminous sources characterized by noticeable and fast changes in brightness at all frequencies. The mechanism that produces this unpredictable variability is under debate, but proposed mechanisms include injection, acceleration and cooling of particles, with possible intervention of shock waves or turbulence. Changes in the viewing angle of the observed emitting knots or jet regions have also been suggested as an explanation of flaring events and can also explain specific properties of blazar emission, such as intra-day variability, quasi-periodicity and the delay of radio flux variations relative to optical changes. Such a geometric interpretation, however, is not universally accepted because alternative explanations based on changes in physical conditions-such as the size and speed of the emitting zone, the magnetic field, the number of emitting particles and their energy distribution-can explain snapshots of the spectral behaviour of blazars in many cases. Here we report the results of optical-to-radio-wavelength monitoring of the blazar CTA 102 and show that the observed long-term trends of the flux and spectral variability are best explained by an inhomogeneous, curved jet that undergoes changes in orientation over time. We propose that magnetohydrodynamic instabilities or rotation of the twisted jet cause different jet regions to change their orientation and hence their relative Doppler factors. In particular, the extreme optical outburst of 2016-2017 (brightness increase of six magnitudes) occurred when the corresponding emitting region had a small viewing angle. The agreement between observations and theoretical predictions can be seen as further validation of the relativistic beaming theory.

The 2021 SIIM-FISABIO-RSNA Machine Learning COVID-19 Challenge: Annotation and Standard Exam Classification of COVID-19 Chest Radiographs.

We describe the curation, annotation methodology, and characteristics of the dataset used in an artificial intelligence challenge for detection and localization of COVID-19 on chest radiographs. The chest radiographs were annotated by an international group of radiologists into four mutually exclusive categories, including "typical," "indeterminate," and "atypical appearance" for COVID-19, or "negative for pneumonia," adapted from previously published guidelines, and bounding boxes were placed on airspace opacities. This dataset and respective annotations are available to researchers for academic and noncommercial use.

Could land cover influence Aedes aegypti mosquito populations?

Aedes aegypti is mainly found in urban environments, where human activity guarantees the permanent availability of potential larval habitats. The present study aimed to test for a possible association between Ae. aegypti infestation and land cover classes. From 23 February to 22 May 2015, immature mosquitoes (except eggs) were sampled in artificial containers identified in dwellings in Córdoba city, Argentina. The proportion of each land cover class was determined by SPOT-5 (Satellites Pour 1'Observation de la Terre or Earth-observing Satellites) image classification. Generalized linear models were developed to assess a suite of predetermined hypotheses and identified cover class variables associated with Ae. aegypti infestation. Arboreal vegetation was identified as the land cover with the greatest relative importance, negatively associated with Ae. aegypti mosquitoes. More infestation was find in areas with less arboreal vegetation, which corresponds to more urbanized areas.

Selecting native perennial plants for ecological intensification in Mediterranean greenhouse horticulture.

Natural control by predators and parasitoids provides an important and often unnoticed ecosystem service to agricultural landscapes by reducing pest populations in crops. The current model of horticultural intensification in south-eastern Spain produces high yields but has also resulted in a landscape almost completely covered by plastic. Promoting natural areas among greenhouses could enhance biodiversity, by being beneficial insects, and reduce pest pressure outdoors. The first step is to ascertain how pests and their natural enemies (NEs) use Mediterranean vegetation for selecting the best plants for pest suppression outdoors. The abundance of the two major horticultural pests, the tobacco whitefly, Bemisia tabaci, and the western flower thrips, Frankliniella occidentalis, together with their NEs, were assayed in 22 flowering perennial plants, which were newly planted in an experimental field surrounded by greenhouses. Eight plant species were identified as the most critical species for sustaining pest populations outdoors. A set of five plant species supported a medium level of pests, and another set of ten plant species supported the lowest level of both pests. Tobacco whitefly occurred in a few plants species, whereas western flower thrips occurred on almost all the plant species studied, and was favoured by the presence of flowers in perennial plants. The results suggest that plant diversity may provide relatively few acceptable host plants for tobacco whitefly than for western flower thrips. NEs were generally collected in plants that also supported abundance of pests, indicating that host/prey availability, more than food resources from flowers, was a stronger predictor of NE abundance in perennial plants. Field trials using the plants with the lowest host acceptance by pests are needed in order to ascertain whether pest abundance outdoors is reduced.

Progressive plasticity during colorectal cancer metastasis.

Metastasis is the principal cause of cancer death, yet we lack an understanding of metastatic cell states, their relationship to primary tumor states, and the mechanisms by which they transition. In a cohort of biospecimen trios from same-patient normal colon, primary and metastatic colorectal cancer, we show that while primary tumors largely adopt LGR5 + intestinal stem-like states, metastases display progressive plasticity. Loss of intestinal cell states is accompanied by reprogramming into a highly conserved fetal progenitor state, followed by non-canonical differentiation into divergent squamous and neuroendocrine-like states, which is exacerbated by chemotherapy and associated with poor patient survival. Using matched patient-derived organoids, we demonstrate that metastatic cancer cells exhibit greater cell-autonomous multilineage differentiation potential in response to microenvironment cues than their intestinal lineage-restricted primary tumor counterparts. We identify PROX1 as a stabilizer of intestinal lineage in the fetal progenitor state, whose downregulation licenses non-canonical reprogramming.

Influence of high power ultrasound on natural microflora, pathogen and lactic acid bacteria in a raw meat emulsion.

Raw meat emulsions may have natural, spoilage and pathogenic microorganisms due to the origin and characteristics of this food matrix. All of these microorganisms must be minimized during industrial processing to make food consumption safe and meet quality regulations. Therefore, in this research, the effect of probe ultrasound on the inactivation of three kinds of microorganisms in a raw meat emulsion is evaluated. The microorganisms are: natural microflora NAM, Listeria monocytogenes LIS, and Lactobacillus delbrueckii LAC. A high-intensity probe ultrasound system was used, during 1.0, 2.5, 5.0, 7.5 and 10 min, with pulsed waves of 0.0, 10, 20 and 30 seg, and 200, 250, 300, 350 and 400 W of power. The interrelation between time, wave pulse cycle, and power factors was assessed. The results showed a positive linear independence effect in the treatments without wave pulse for each microorganism, and a quadratic interaction with the time and the ultrasound power for the inactivation of the three kinds of microorganisms. Besides, the desirability function for the inactivation reached up to 60% of the microbial population with the probe ultrasound treatment, with 10 min, a 7.56 s wave pulse and 400 W of power. Thus, these results could be useful to decide the incorporation of mild and emerging technologies in a meat industry line process.

Fractal dimension and mechanism of aggregation of apple juice particles.

Turbidity of freshly squeezed apple juice is produced by a polydisperse suspension of particles coming from the cellular tissue. After precipitation of coarse particles by gravity, only fine-colloidal particles remain in suspension. Aggregation of colloidal particles leads to the formation of fractal structures. The fractal dimension is a measure of the internal density of these aggregates and depends on their mechanism of aggregation. Digitized images of primary particles and aggregates of depectinized, diafiltered cloudy apple juice were obtained by scanning electron microscopy (SEM). Average radius of the primary particles was found to be a = 40 ± 11 nm. Maximum radius of the aggregates, R(L), ranged between 250 and 7750 nm. Fractal dimension of the aggregates was determined by analyzing SEM images with the variogram method, obtaining an average value of D(f) = 2.3 ± 0.1. This value is typical of aggregates formed by rapid flocculation or diffusion limited aggregation. Diafiltration process was found to reduce the average size and polydispersity of the aggregates, determined by photon correlation spectroscopy. Average gyration radius of the aggregates before juice diafiltration was found to be R(g) = 629 ± 87 nm. Average number of primary particles per aggregate was calculated to be N = 1174.

Surgical treatment of periprosthetic humerus fractures and algorithm. / Tratamiento quirúrgico de las fracturas periprotésicas de húmero y algoritmo de actuación.

INTRODUCTION: Periprosthetic humerus fractures are infrequent and sometimes difficult to treat. There is limited literature and no consensus on the handling of these fractures. The objective of this study was to compare our results with those published in the literature, in order to improve our care and propose a management algorithm. MATERIAL AND METHOD: Observational study of 10cases of periprosthetic humerus fractures with a mean follow-up of the patients of 23months. An analysis of sociodemographic, radiological and surgical variables was performed. They were reviewed clinically and by telephone using the UCLA Shoulder Score and Quick-DASH scales. A systematic search was made in Pubmed for periprosthetic humerus fractures, for a literature review with which to compare our series. RESULTS: We analysed 10patients with an average age of 69.4years (37-91). Of the patients, 90% underwent surgery through open reduction and internal fixation. Nine of the ten patients consolidated in a mean time of 6.2months (range 5-12), the remaining suffered a new fracture 5months after the intervention, who were reoperated and a new osteosynthesis performed with bone allograft. In the UCLA scale there was a decrease of 10.66points, and an increase of 27.3points in the Quick-DASH, at the end of the follow-up. CONCLUSIONS: In our series of cases we found similarities in the literature, in relation to demographic aspects and obtaining good radiographic results, which do not correspond to the functional outcome of patients.

Structure and evolution of magnetohydrodynamic solitary waves with Hall and finite Larmor radius effects.

Nonlinear and low-frequency solitary waves are investigated in the framework of the one-dimensional Hall-magnetohydrodynamic model with finite Larmor effects and two different closure models for the pressures. For a double adiabatic pressure model, the organization of these localized structures in terms of the propagation angle with respect to the ambient magnetic field θ and the propagation velocity C is discussed. There are three types of regions in the θ-C plane that correspond to domains where either solitary waves cannot exist, are organized in branches, or have a continuous spectrum. A numerical method valid for the two latter cases, which rigorously proves the existence of the waves, is presented and used to locate many waves, including bright and dark structures. Some of them belong to parametric domains where solitary waves were not found in previous works. The stability of the structures has been investigated by performing a linear analysis of the background plasma state and by means of numerical simulations. They show that the cores of some waves can be robust, but, for the parameters considered in the analysis, the tails are unstable. The substitution of the double adiabatic model by evolution equations for the plasma pressures appears to suppress the instability in some cases and to allow the propagation of the solitary waves during long times.

Organic matter humification by vermicomposting of cattle manure alone and mixed with two-phase olive pomace.

The chemical changes occurring in a cattle manure (CM) and a mixture of two-phase olive pomace and CM (OP+CM) after vermicomposting with Eisenia andrei for eight months were evaluated. Further, humic acid (HA)-like fractions were isolated from the two substrates before and after the vermicomposting process, and analyzed for elemental and acidic functional group composition, and by ultraviolet/visible, Fourier transform infrared and fluorescence spectroscopies. Before vermicomposting, the HA-like fractions featured a prevalent aliphatic character, large C contents, small O and acidic functional group contents, a marked presence of proteinaceous materials and polysaccharide-like structures, extended molecular heterogeneity and small degrees of aromatic ring polycondensation, polymerisation and humification. After vermicomposting, the total extractable C and HA-C contents in the bulk substrates increased, and the C and H contents, aliphatic structures, polypeptidic components and carbohydrates decreased in the HA-like fractions, whereas O and acidic functional group contents increased. Further, an adequate degree of maturity and stability was achieved after vermincomposting, and the HA-like fractions, especially that from OP+CM, approached the characteristics typical of native soil HA. Vermicomposting was thus able to promote organic matter humification in both CM alone and in the mixture OP+CM, thus enhancing the quality of these materials as soil organic amendments.

Hydrolytic enzyme activities of extracted humic substances during the vermicomposting of a lignocellulosic olive waste.

Humic substances and three hydrolytic enzymes (beta-glucosidase, phosphatase and urease) were extracted by neutral sodium pyrophosphate from an olive waste (dry olive cake), alone or mixed with municipal biosolids, during a nine month vermicomposting process. Easily degradable compounds decreased during the vermicomposting process because of microbial consumption. When municipal biosolids were added to dry olive cake, microbial activity increased and the amounts of compounds extracted by pyrophosphate were three times lower than olive cake alone. In both instances, beta-glucosidase, phosphatase and urease activities of the organic extracts either increased or remained the same after a nine month period of vermicomposting, thus suggesting that the humus enzyme complexes resisted microbial and earthworm attack. It is known that humus immobilised enzymes also remain active in soil environments, reactivating the nutrient cycles in soil. The use as amendments of vermicomposted olive cake, alone or when mixed with biosolids, could be a good alternative to reactivate the C, P and N-cycles in degraded soils for regeneration purposes.

Cloning of a ras-related gene from Hydra which responds to head-specific signals.

Members of the Ras family of proteins are important components of signal transduction pathways responding to external signals and leading to changes in cell behavior. Analysis of two ras-related genes in the phylogenetically old metazoan Hydra indicates that in normal animals both genes are expressed in all body regions of the polyp. Upon head removal, however, the transcript level of one of the two genes, ras2, decreases rapidly in the upper gastric region which is adjacent to the former head. The decrease is transient and specific for ras2, since no changes could be observed in the transcript level of the related ras1 gene or any other gene. The disappearance of the ras2 mRNA can be prevented completely by brief exposure of decapitated polyps to the protein kinase C activator TPA, which previously was shown to be capable of converting gastric tissue into head tissue [Müller, W.A. In: Othmer, H.G. (Ed.) Experimental and Theoretical Advances in Biological Pattern Formation. Plenum Press, New York, NY, 1993, pp. 237-253]. The finding that Hydra ras2 expression is strongly dependent on a signal from the head provides the first evidence for ras expression being regulated in pattern formation.

Detection of Trichinella infection in slaughter horses by ELISA and western blot analysis.

In order to determine the presence of Trichinella infections in horses slaughtered at an abattoir in Mexico, 147 serum samples were examined by two immunoenzymatic methods. Specific antibodies were detected by ELISA in 7% of the serum samples at a dilution 1:400 and in 10% at lower dilutions (1:20, 1:40) using Trichinella spiralis muscle larvae (ML) excretory/secretory (E/S) products. Serum samples from four naturally infected horses (confirmed by direct methods) gave negative O.D. values in an ELISA at a 1:400 dilution and only two of them were positive at a 1:20 and 1:40 dilutions. Serum samples from experimentally infected horses reacted by Western blotting with ML components with molecular weights of 47, 52, 59, 67, 72 and 105 kDa which correspond to the TSL-1 antigens. Serum samples from the four naturally infected horses and from the abattoir horses that were positive in ELISA using E/S antigens recognized several ML components, some of them reacted with all the TSL-1 antigens mentioned above and others recognized preferentially two or three of these molecules. Since the serologic assays may not offer the sensitivity required in the diagnosis of horses trichinellosis and the direct methods had not always been useful in the detection of larvae in horsemeat related to trichinellosis outbreaks in Europe, it is proposed that additional assays are performed to determine Trichinella infection in horses. These can include detection of parasite antigens by ELISA and Dot ELISA or PCR, which in turn may also help to determine the presence of the parasite in early and late infections of horses.

Detection of Trichinella spiralis muscle larvae in naturally infected horses.

Human trichinellosis outbreaks related to horsemeat consumption have been reported in France and Italy in recent years. In order to determine if Trichinella is present in horses slaughtered at an abattoir in the State of Mexico, diaphragm muscle tissue samples (22-37 g) from 80 horses were examined by artificial digestion. Four of these samples had larvae that were characterized as Trichinella sp. by morphological criteria and as Trichinella spiralis by the polymerase chain reaction.

[Analysis criteria's influence on incidence and factors associated tuberculin conversion in health care workers]. / Influencia del criterio de análisis sobre la incidencia y los factores de riesgo de conversión tuberculínica en personal sanitario.

BACKGROUND: To know from two different criteria, CDC's and Spanish national consensus (NC), the tuberculin conversion rate and the factors associated to this phenomenon. PATIENTS AND METHODS: A retrospective cohort study was designed over 475 health care workers. Risk factors were identified by using a Cox's proportional hazards model for each criteria. RESULTS: Not being vaccinated with BCG appears to be a risk factor in NC model 5.37 (CI 95%: 2.21-13.00) and does not in CDC. There was a difference of 45% between both incidence density rates. CONCLUSIONS: We did not find a total concordance between the results from the two models.

[Corn starch in the treatment of patients with glycogenosis type I and III]. / Almidón de maíz crudo en el tratamiento de pacientes con glucogenosis tipo I y III.

RATIONALE: Administering raw corn starch can maintain normoglycemia for long periods after being ingested, thus facilitating control in patients with type I and III glycogenosis. METHODS: The metabolic effects and the effects on the nutritional status of a treatment with fractionated administrations of raw starch are assessed in two patients with type I glycogenosis (ages 18 and 12 years) and one patient with type III glycogenosis (aged 13 years). In the first two cases the response was previously studied after administering a load of raw corn starch in a water suspension, in an amount similar to the estimated rate of endogenous glucose production during the fasting period (5 mg/kg/minute). RESULTS: The results of the overload of starch showed a normoglycemia and an absence of lactoacidosis between 4 and 6 hours after its ingestion. The three patients were given two doses of raw corn starch (2 g/kg/dose) at 1.00 and 5.00 hours during the night. After one year of treatment, all patients showed glycemia levels at 9.00 AM that were greater than 90 mg/dl and lactic acid levels that were lower than 2.4 mmol/l. Moreover, in two of the cases there was an increase in the growth rate. In all cases the amount of the hepatomegaly decreased as did the size of the hepatic adenomas that were present in two of the cases. CONCLUSIONS: In patients with type I and III glycogenosis, raw corn starch can balance the results of the nightly gastric glucose infusion, both with regard to the metabolic control and with regard to the growth.

Swine trichinellosis in slaughterhouses of the metropolitan area of Toluca.

In order to determine the prevalence of Trichinella spiralis infections in abattoirs of the metropolitan area of Toluca where pigs from commercial farms as well as backyard pigs are slaughtered, 539 swine diaphragm tissue samples were collected and examined by trichinoscopy and artificial digestion. Serum samples from the same animals were analyzed by ELISA using somatic and excretory/secretory antigens, and by Western blot analysis. T. spiralis muscle larvae were not found by trichinoscopy or artificial digestion. However, specific antibodies were detected by ELISA and confirmed by Western blotting in 12.4% of the serum samples examined. Analysis of risk factors showed no association of seropositive results with sex. However, significant higher risk was observed in swine seven to 12 months old and in backyard pigs, compared with pigs from commercial farms.

[Survival analysis following the addition of temozolomide to surgery and radiotherapy in patients with glioblastoma multiforme]. / Análisis de la supervivencia global al añadir temozolamida al tratamiento quirúrgico y radioterápico en pacientes con glioblastoma multiforme.

OBJECTIVES: To analyze the effect of different therapies -surgery, radiotherapy, and chemotherapy (temozolomide)- on the survival of various groups of patients with glioblastoma multiforme (GBM). METHOD: The overall survival of a total of 85 patients with histopathological diagnosis of GBM was analyzed (descriptive statistics, Kaplan-Meier). Patients were divided into 4 treatment groups: group 1 (n=12), untreated patients (" no treatment" option was chosen by the family); group 2 (n=22), patients undergoing surgery only (retrospective series from the 1980s); group 3 (n=24), patients undergoing surgery + standard radiotherapy (control group, partially effective treatment); group 4 (n=27), patients undergoing surgery + radiotherapy + chemotherapy (temozolomide [TMZ]) (current study group). RESULTS: Mean age (one-way ANOVA) showed no significant difference between the groups. Mean/median survival (weeks) was as follows: group 1, 18/16; group 2, 23/14; group 3, 48/42; group 4, 70/64. The Kaplan-Meier analysis yielded the following 50% survival cutoffs (weeks): group 1, 16.00; group 2, 14.29; group 3, 42.00; group 4, 64.43. This demonstrated a significant difference when radiotherapy (group 3) was added to surgery (group 2) or no treatment (group 1), and a significant difference (p < 0.001) in survival when TMZ (group 4) was added to the so far considered as being the standard treatment (group 3: surgery + radiotherapy). CONCLUSIONS: Surgery alone does not result in a higher survival rate for GBM patients. However, surgery allows to establish a histopathological diagnosis, to improve signs and symptoms which are attributable to intracranial hypertension or tumour topography, and to reduce the number of target cells for adjunctive therapies. Radiotherapy improves survival and TMZ chemotherapy that is given after radiotherapy adds further survival benefit for patients.

[Congenital absence of the vagina. Mayer-Rokitansky-Kuster-Hauser syndrome. Presentation of a case and review of the literature]. / Ausencia congénita de vagina. Síndrome Mayer-Rokitansky-Kuster-Hauser. Presentación de un caso y revisión de la literatura.

The normal development of the feminine reproductive tract depends on complete interaction between genetic, hormonal and environmental factors to produce the differentiation of the Müellerian, Wolff and urogenital sinus. The alteration in this balance result in a wide spectrum of the reproductive tract anomalies including imperforated hymen, vaginal septum, vaginal atresia, incomplete fusion of the Müellerian conducts and Müellerian aplasia. In order to evaluate the feminine genital tract disorders, we studied a feminine with amenorrhea and primary sterility. Ultrasonography and diagnosis laparoscopy where performed. Incomplete fusion of Müellerian conducts was observed. Blood genetics tests plus biopsy of ovarian tissue were taken which reported 46 XX karyotype with no structural anomalies. Conservative evaluation and management.