To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The giant gypsum crystals of Naica cave have fascinated scientists since their discovery in 2000. Human activity has changed the microclimate inside the cave, making scientists wonder about the potential environmental impact on the crystals. Over the last 9 years, we have studied approximately 70 samples. This paper reports on the detailed chemical–structural characterization of the impurities present at the surface of these crystals and the experimental simulations of their potential deterioration patterns. Selected samples were studied by petrography, optical and electronic microscopy, and laboratory X-ray diffraction. 2D grazing incidence X-ray diffraction, X-ray μ-fluorescence, and X-ray μ-absorption near-edge structure were used to identify the impurities and their associated phases. These impurities were deposited during the latest stage of the gypsum crystal formation and have afterward evolved with the natural high humidity. The simulations of the behavior of the crystals in microclimatic chambers produced crystal dissolution by 1–4% weight fraction under high CO2 concentration and permanent fog, and gypsum phase dehydration under air and CO2 gaseous environment. Our work suggests that most surface impurities are of natural origin; the most significant anthropogenic damage on the crystals is the extraction of water from the caves.
Technological and mathematical advances have provided opportunities to investigate new approaches for the holistic quantification of complex biological systems. One objective of these approaches, including the multi-inverse deterministic approach proposed in this paper, is to deepen the understanding of biological systems through the structural development of a useful, best-fitted inverse mechanistic model. The objective of the present work was to evaluate the capacity of a deterministic approach, that is, the multi-inverse approach (MIA), to yield meaningful quantitative nutritional information. To this end, a case study addressing the effect of diet composition on sheep weight was performed using data from a previous experiment on saccharina (a sugarcane byproduct), and an inverse deterministic model (named Paracoa) was developed. The MIA successfully revealed an increase in the final weight of sheep with an increase in the percentage of corn in the diet. Although the soluble fraction also increased with increasing corn percentage, the effective nonsoluble degradation increased fourfold, indicating that the increased weight gain resulted from the nonsoluble substrate. A profile likelihood analysis showed that the potential best-fitted model had identifiable parameters, and that the parameter relationships were affected by the type of data, number of parameters and model structure. It is necessary to apply the MIA to larger and/or more complex datasets to obtain a clearer understanding of its potential.
Psychiatric illnesses have a high prevalence in the general population. Psychiatric illnesses affect the way other medical processes develop: age of onset, distribution by gender, type an evolution, and the training of the psychiatrists in caring for them.
To describe the characteristics and the medical problems of patients who have been consulted by an Internal Medicine Liaison Unit while hospitalized in the Psychiatric Unit of a third level hospital. Comparison of the general profile of these patients and their consultations with that done to patients hospitalizad in the rest of the hospital.
Descriptive retrospective study from September 2007 to May 2010. Use of a centralized database created with of all the administrative and clinical details regarding the consultation. A p ≤ 0.05 has statistical significance.
648 patients were identified (40,7% men). Mean age 52.4 years. Mean stay 3 days. 34,4% were solved in one visit. Mortality rate 0,3%. 94,1% of discharges were due to recovery, the rest were transfered to another service.
Distribution by major diagnostic groups: infectious 16,2%, cardiorespiratory 15,4%, mental illness 12,9%, metabolic 10,4%, tumoral 8,5%, digestive 8,2%, not defined 8,2%, hematologic 5%, others 15,2%.
The psychiatric patient is clearly younger and the female gender is slightly higher (59,3%) than in the control group. In this group the infectious and cardiorespiratoty illnesses predominate. The percentage of psychiatric consultations (34,1%; 648) over our global (1906) is impressive since the number of psychiatric inpatients is not proportional to this number.
Auditory hallucinations in deaf people are known since the XIX century. However, research in this area is scarce.
Auditory hallucinations can be caused by alterations in receptors, stimulus carrying routes or cerebral centres. Therefore, they can take place in persons without mental illness.
Bibliographical review in literature and pub med using as key words: “Auditory hallucinations, Auditory deficit,
– There is always chronic hearing loss caused by an auditory injury.
– Higher prevalence in females with acute or gradual onset.
– Usually unilateral.
– Most common phenomena are musical hallucinations.
– Not associated with other types of hallucinations.
– Can be modified by attention and will.
– It is a hallucinosis.
– Not accompanied by disturbances of consciousness, memory or judgment.
– Treatment of hearing impairment leads to healing. Results are unsatisfactory with psychotropic drugs. Psychoeducation may lead to improvements.
The existence of auditory hallucinations with consciousness of unreality rules out an organic pathology. It is important to assess hearing, because an entity has been defined by musical auditory hallucinations with unreality conscious and with preserved judgment, memory and consciousness, in patients with acquired hearing loss, mainly women and elderly, called by many professionals ACBS. Awareness of this entity by specialists in otolaryngology and psychiatry is essential.
We studied the genetic diversity and the population structure of human isolates of Histoplasma capsulatum, the causative agent of histoplasmosis, using a randomly amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) assay to identify associations with the geographic distribution of isolates from Mexico, Guatemala, Colombia and Argentina. The RAPD-PCR pattern analyses revealed the genetic diversity by estimating the percentage of polymorphic loci, effective number of alleles, Shannon's index and heterozygosity. Population structure was identified by the index of association (IA) test. Thirty-seven isolates were studied and clustered into three groups by the unweighted pair-group method with arithmetic mean (UPGMA). Group I contained five subgroups based on geographic origin. The consistency of the UPGMA dendrogram was estimated by the cophenetic correlation coefficient (CCCr = 0.94, P = 0.001). Isolates from Mexico and Colombia presented higher genetic diversity than isolates from Argentina. Isolates from Guatemala grouped together with the reference strains from the United States of America and Panama. The IA values suggest the presence of a clonal population structure in the Argentinian H. capsulatum isolates and also validate the presence of recombining populations in the Colombian and Mexican isolates. These data contribute to the knowledge on the molecular epidemiology of histoplasmosis in Latin America.
To examine snacking patterns, food sources and nutrient profiles of snacks in low- and middle-income Chilean children and adolescents.
Cross-sectional. Dietary data were collected via 24 h food recalls. We determined the proportion of snackers, snacks per day and energy from top food and beverage groups consumed. We compared the nutrient profile (energy, sodium, total sugars and saturated fat) of snacks v. meals.
South-east region of Chile.
Children and adolescents from two cohorts: the Food Environment Chilean Cohort (n 958, 4–6 years old) and the Growth and Obesity Cohort Study (n 752, 12–14 years old).
With a mean of 2·30 (se 0·03) snacks consumed daily, 95·2 % of children and 89·9 % of adolescents reported at least one snacking event. Snacks contributed on average 1506 kJ/d (360 kcal/d) in snacking children and 2218 kJ/d (530 kcal/d) in snacking adolescents (29·0 and 27·4 % daily energy contribution, respectively). Grain-based desserts, salty snacks, other sweets and desserts, dairy foods and cereal-based foods contributed the most energy from snacks in the overall sample. For meals, cereal-based foods, dairy beverages, meat and meat substitutes, oils and fats, and fruits and vegetables were the top energy contributors.
Widespread snacking among Chilean youth provides over a quarter of their daily energy and includes foods generally considered high in energy, saturated fat, sodium and/or total sugars. Future research should explore whether snacking behaviours change as the result of Chile’s national regulations on food marketing, labelling and school environments.
Thousands of new asteroids are discovered every year and the rate of discovery is by far larger than the determination rate of their physical properties. In 2015 a group of researchers and students of several Mexican institutions have established an observational program to study asteroids photometrically. The program, named Mexican Asteroid Photometry Campaign, is aiming to derive rotation periods of asteroids based on optical photometric observations. Since then four campaigns have been carried out. The results obtained throughout these campaigns, as well as future work, are presented.
Human papillomavirus (HPV) is a DNA virus linked to mucosal and cutaneous carcinogenesis. More than 200 different HPV types exist. We carried out a transversal study to investigate the prevalence of HPV types in two regions of Mexico. A total of 724 genital and non-genital samples from women (F) and men (M) were studied; 241 (33%) from North-Eastern (NE) and 483 (66%) from South-Central (SC) Mexico. The overall prevalence was 87%. In genital lesions from females, the NE group showed a prevalence of HPV types 16 (37%), 6 (13%), 59 (6%), 11, 18 and 66 (5.4% each); and the SC group showed types 6 (17%), 16 (15%), 11 (14.5%), 18 (12%) and 53 (6%). In the genital lesions from males, NE group showed types 16 (38%), 6 (21%), 11 (13%) and 59 plus 31 (7.5%) and the SC group showed types 6 (25%), 11 (22%), 18 (17%) and 16 (11.5%). When the two regions were compared, a higher prevalence of low-risk HPV 6 and 11 was found in the SC region and of high-risk HPV 59, 31 and 66 (the latter can also be present in benign lesions) in the NE region. Our findings complement efforts to understand HPV demographics as a prerequisite to guide and assess the impact of preventive interventions.
Exposure to prenatal hypoxia in rats leads to intrauterine growth restriction (IUGR), decreases fetal cardiomyocyte proliferation and increases the risk to develop cardiovascular diseases (CVD) later in life. The tumor necrosis factor-related weak inducer of apoptosis (TWEAK) induces cardiomyocyte proliferation through activation of the fibroblast growth factor-inducible molecule 14 (Fn-14) receptor. The TWEAK/Fn-14 pathway becomes quiescent shortly after birth, however, it becomes upregulated with CVD; suggesting that it could be a link between the increased susceptibility to CVD in pregnancies complicated by hypoxia/IUGR. We hypothesized that offspring exposed to prenatal hypoxia will exhibit reduced cardiomyocyte proliferation due to reduced Fn-14 expression and that the TWEAK/Fn-14 pathway will be expressed in those adult offspring. We exposed pregnant Sprague Dawley rats to control (21% oxygen) or hypoxic (11% oxygen) conditions from gestational days 15 to 21. Ventricular cardiomyocytes were isolated from male and female, control and hypoxic offspring at postnatal day 1. Proliferation was assessed in the presence or absence of r-TWEAK (72 h, 100 ng/ml). Prenatal hypoxia was not associated with differences in Fn-14 protein expression in either male or female offspring. Cardiomyocytes from prenatal hypoxic male, but not female, offspring had decreased proliferation compared with controls. Addition of r-TWEAK increased cardiomyocyte proliferation in all offspring. In adult offspring of all groups, the TWEAK/Fn-14 pathway was not detectable. Cardiomyocyte proliferation was reduced in only male offspring exposed to prenatal hypoxia but this was not due to changes in the Fn-14 pathway. Studies addressing other pathways associated with CVD and prenatal hypoxia are needed.
The care of patients with CHD remains a challenge in low- and middle-income countries. Their health systems have not been able to achieve consistently high performance in this field. The large volume of patients, manpower constraints, inconsistencies in the level and type of background training of the teams caring for this patient population, and the inadequate quality control systems are some of the barriers to achieving excellence of care. We describe three different international projects supporting the paediatric cardiac surgical and paediatric cardiac intensive care programmes in Latin America, Asia, and the Caribbean.
TAOS II is a next-generation occultation survey with the goal of measuring the size distribution of the small end of the Kuiper Belt (objects with diameters 0.5–30 km). Such objects have magnitudes r > 30, and are thus undetectable by direct imaging. The project will operate three telescopes at San Pedro Mártir Observatory in Baja California, México. Each telescope will be equipped with a custom-built camera comprised of a focal-plane array of CMOS imagers. The cameras will be capable of reading out image data from 10,000 stars at a cadence of 20 Hz. The telescopes will monitor the same set of stars simultaneously to search for coincident occultation detections, thus minimising the false-positive rate. This talk described the project, and reported on the progress of the development of the survey infrastructure.
Core subset selection from collections hosted by seed banks, grow in importance as the number of accessions and genetic marker information rapidly increases. A data set of 20,526 single-nucleotide polymorphism (SNP) markers characterizing 7986 Mexican creole wheat landraces, was used to test 11 methods for core subset selection, through optimization criteria containing average genetic distance and genetic diversity. Allele richness was used as an additional criterion to qualify the generated core subsets. Three replications with random samples of 1500 SNP loci, each comprising a maximum of 3000 alleles, were used to perform the method evaluations through four different objective functions. The LR greedy search (LR) and LR with random first pair (LRSemi) were consistently best across all assays for maximizing the objective functions, and they performed well even for criteria not included in those functions. The Tukey's HSD (honest significant difference) multiple comparisons grouped those methods together with the sequential forward selection (SFS) and SFS with random first pair (SFSSemi) strategies as the top set of approaches. All of them are simple heuristic maximization algorithms, and outperformed two more sophisticated optimization approaches: parallel mixed replica exchange and replica exchange Monte Carlo. For their efficiency to optimize the objective functions and computing speed, the LRSemi and SFSSemi methods demonstrated to be good alternatives for core subset selection from large collections of highly homozygous accessions characterized by many biallelic markers.
To evaluate the agreement between the current National Healthcare Safety Network (NHSN) definition for ventriculitis and others found in the literature among patients with an external ventricular drain (EVD)
Retrospective cohort study from January 2009 to December 2014
Neurology and neurosurgery intensive care unit of a large tertiary-care center
Patients with an EVD were included. Patients with an infection prior to EVD placement or a permanent ventricular shunt were excluded.
We reviewed the charts of patients with positive cerebrospinal fluid (CSF) cultures and/or abnormal CSF results while they had an EVD in place and applied various ventriculitis definitions.
We identified 48 patients with a total of 52 cases of ventriculitis (41 CSF culture-positive cases and 11 cases based on abnormal CSF test results) using the NHSN definition. The most common organisms causing ventriculitis were gram-positive commensals (79.2%); however, 45% showed growth of only 1 colony on 1 piece of media. Approximately 60% of the ventriculitis cases by the NHSN definition met the Honda criteria, approximately 56% met the Gozal criteria, and 23% met Citerio’s definition. Cases defined using Honda versus Gozal definitions had a moderate agreement (κ=0.528; P<.05) whereas comparisons of Honda versus Citerio definitions (κ=0.338; P<.05) and Citerio versus Gozal definitions (κ=0.384; P<.05) had only fair agreements.
The agreement between published ventriculostomy-associated infection (VAI) definitions in this cohort was moderate to fair. A VAI surveillance definition that better defines contaminants is needed for more homogenous application of surveillance definitions between institutions and better comparison of rates.
Dynamic mechanical properties of polypropylene (PP) and grafted polypropylene (PP-g-MA) composites reinforced with acetylated wheat straw fibers (WSF) is reported in this work. The materials were prepared with different fiber particle sizes (40, 80 and 140 U.S. mesh) and at different fiber contents (5, 10 and 15 wt.%). The PP and PP-g-MA composites, where anhydride maleic (MA) was used as coupling agent, were obtained using a twin-screw extruder; whereas an injection-molding machine molded the composite pellets into testing specimens. To observe the morphology of the composites, micrographs were taken with an optical microscope. The Dynamic mechanical properties were analyzed using a torsional rheometer. The morphological analysis showed a high porous structure somehow similar to foamed materials. The storage modulus (G′) increased by increasing the fiber content, and decreased with fiber particle sizes for the PP composites. Meanwhile, the use of the coupling agent additive promoted a modulus increase due to higher fiber-polymer interaction, from better adhesion and chemical bonds formation between the fibers-coupling agent-PP.
The role of the initial bacterial inoculates on the biocorrosion of API X52 pipeline steel coupons was evaluated by electrochemical noise technique. The experiments were performed under laboratory conditions using an aerobic bacteria identified as Achromobacter xylosoxidans. Inoculations in the interval strain of 1x104 – 1x108 CFU/ml were evaluated. Environmental scanning electron microscopy (ESEM) analysis was carried out to evaluate the corrosive effects induced on the API X52 electrodes. The results show that all corroded surfaces show sites of localized corrosion, however, the density of de sites of localized corrosion have different grades depending of the initial inoculation used during the experiments. The maximum density sites of localized corrosion were obtained in the experiments with 1x105 CFU/ml. From inoculates of 1x106 CFU/ml the density sites of localized corrosion diminished constantly. The results show that with inoculates over 1x106 CFU/ml, the oxygen demand for the bacterial strain limits the presence of oxygen available into the metallic surface to maintain the corrosion reactions. The results were supported by the EDX analysis of the corrosion products formed on the metallic surfaces where the oxygen peaks diminished as the bacterial inoculation increases.
Exoplanetary transit observations were carried out for the first time with all the three telescopes at the San Pedro Mártir National Astronomical Observatory in Baja California, Mexico.
We present preliminary results on WASP-39 and WASP-43, two Hot Jupiters known for the presence of a highly-inflated radius. Using the defocused photometry technique, we observed these systems, achieving photometric precision of ± 3–5mmag peak-to-valley. The preliminary fit of their lightcurves shows physical and orbital parameters consistent with published results.
Cadmium sulfide (CdS) films were deposited onto glass substrates by chemical bath deposition (CBD) from a bath containing cadmium acetate, ammonium acetate, thiourea, and ammonium hydroxide. The CdS thin films were annealed in argon (neutral atmosphere) or hydrogen (reducing atmosphere) for 1 h at various temperatures (300, 350, 400, 450 and 500 °C). The changes in optical and electrical properties of annealed treated CdS thin films were analyzed. The results showed that, the band-gap and resistivity depend on the post-deposition annealing atmosphere and temperatures. Thus, it was found that these properties of the films, were found to be affected by various processes with opposite effects, some beneficial and others unfavorable. The energy gap and resistivity for different annealing atmospheres was seen to oscillate by thermal annealing. Recrystallization, oxidation, surface passivation, sublimation and materials evaporation were found the main factors of the heat-treatment process responsible for this oscillating behavior. Annealing over 400 °C was seen to degrade the optical and electrical properties of the film.