Frequency-Dependent Squeezing for Advanced LIGO.

The first detection of gravitational waves by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in 2015 launched the era of gravitational-wave astronomy. The quest for gravitational-wave signals from objects that are fainter or farther away impels technological advances to realize ever more sensitive detectors. Since 2019, one advanced technique, the injection of squeezed states of light, is being used to improve the shot-noise limit to the sensitivity of the Advanced LIGO detectors, at frequencies above ∼50 Hz. Below this frequency, quantum backaction, in the form of radiation pressure induced motion of the mirrors, degrades the sensitivity. To simultaneously reduce shot noise at high frequencies and quantum radiation pressure noise at low frequencies requires a quantum noise filter cavity with low optical losses to rotate the squeezed quadrature as a function of frequency. We report on the observation of frequency-dependent squeezed quadrature rotation with rotation frequency of 30 Hz, using a 16-m-long filter cavity. A novel control scheme is developed for this frequency-dependent squeezed vacuum source, and the results presented here demonstrate that a low-loss filter cavity can achieve the squeezed quadrature rotation necessary for the next planned upgrade to Advanced LIGO, known as "A+."

Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy.

The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).

Protein expression parallels thermal tolerance and ecologic changes in the diversification of a diving beetle species complex.

Physiological changes associated with evolutionary and ecological processes such as diversification, range expansion or speciation are still incompletely understood, especially for non-model species. Here we study differences in protein expression in response to temperature in a western Mediterranean diving beetle species complex, using two-dimensional differential gel electrophoresis with one Moroccan and one Iberian population each of Agabus ramblae and Agabus brunneus. We identified proteins with significant expression differences after thermal treatments comparing them with a reference EST library generated from one of the species of the complex (A. ramblae). The colonisation during the Middle Pleistocene of the Iberian peninsula by A. ramblae, where maximum temperatures and seasonality are lower than in the ancestral north African range, was associated with changes in the response to 27 °C in proteins related to energy metabolism. The subsequent speciation of A. brunneus from within populations of Iberian A. ramblae was associated with changes in the expression of several stress-related proteins (mostly chaperons) when exposed to 4 °C. These changes are in agreement with the known tolerance to lower temperatures of A. brunneus, which occupies a larger geographical area with a wider range of climatic conditions. In both cases, protein expression changes paralleled the evolution of thermal tolerance and the climatic conditions experienced by the species. However, although the colonisation of the Iberian peninsula did not result in morphological change, the speciation process of A. brunneus within Iberia involved genetic isolation and substantial differences in male genitalia and body size and shape.

High potential of symbiotic interactions between native mycorrhizal fungi and the exotic tree Eucalyptus camaldulensis for phytostabilization of metal-contaminated arid soils.

Waste dumps generated by mining activities contain heavy metals that are dispersed into areas leading to significant environmental contamination. The objectives of this study were (i) to survey native plants and their associated AM fungal communities from waste soils in a Moroccan mine site and (ii) to follow Eucalyptus growth in soil collected from the waste-mine. AM spores from native plant species were collected from the mining site and the surrounding uncontaminated areas were multiplied and inoculated onto Eucalyptus camaldulensis. The results showed that (i) the native plant species recorded in the waste did not show an active metal uptake, (ii) the selected native plant species are associated with AM mycorrhizal fungi and (iii) the use of AM fungi adapted to these drastic conditions can improve the growth of the fast-growing tree, E. camaldulensis and its tolerance to high soil Cu content. In conclusion, it is suggested that in order to define efficient low-cost phytostabilization processes, the use of native resources (i.e., mixtures of native mycorrhizal fungi) in combination with fast-growing tree species such as Eucalyptus, could be used to optimize the establishment of a permanent cover plant in contaminated areas.

Differing courses of genetic evolution of Bradyrhizobium inoculants as revealed by long-term molecular tracing in Acacia mangium plantations.

Introducing nitrogen-fixing bacteria as an inoculum in association with legume crops is a common practice in agriculture. However, the question of the evolution of these introduced microorganisms remains crucial, both in terms of microbial ecology and agronomy. We explored this question by analyzing the genetic and symbiotic evolution of two Bradyrhizobium strains inoculated on Acacia mangium in Malaysia and Senegal 15 and 5 years, respectively, after their introduction. Based on typing of several loci, we showed that these two strains, although closely related and originally sampled in Australia, evolved differently. One strain was recovered in soil with the same five loci as the original isolate, whereas the symbiotic cluster of the other strain was detected with no trace of the three housekeeping genes of the original inoculum. Moreover, the nitrogen fixation efficiency was variable among these isolates (either recombinant or not), with significantly high, low, or similar efficiencies compared to the two original strains and no significant difference between recombinant and nonrecombinant isolates. These data suggested that 15 years after their introduction, nitrogen-fixing bacteria remain in the soil but that closely related inoculant strains may not evolve in the same way, either genetically or symbiotically. In a context of increasing agronomical use of microbial inoculants (for biological control, nitrogen fixation, or plant growth promotion), this result feeds the debate on the consequences associated with such practices.

Impact of Sepsis Flow Chip, a novelty fast microbiology method, in the treatment of bacteremia caused by Gram-negative bacilli.

OBJECTIVE: The aim of this study was to assess the impact of the information provided by the new Sepsis Chip Flow system (SFC) and other fast microbiological techniques on the selection of the appropriate antimicrobial treatment by the clinical researchers of an antimicrobial stewardship team. METHODS: Two experienced clinical researchers performed the theoretical exercise of independently selecting the treatment for patients diagnosed by bacteremia due to bacilli gram negative (BGN). At first, the clinicians had only available the clinical characteristics of 74 real patients. Sequentially, information regarding the Gram stain, MALDI-TOF, and SFC from Vitro were provided. Initially, the researchers prescribed an antimicrobial therapy based on the clinical data, later these data were complementing with information from microbiological techniques, and the clinicians made their decisions again. RESULTS: The data provided by the Gram stain reduced the number of patients prescribed with combined treatments (for clinician 1, from 23 to 7, and for clinician 2, from 28 to 12), but the use of carbapenems remained constant. In line with this, the data obtained by the MALDI-TOF also decreased the combined treatment, and the use of carbapenems remained unchanged. By contrast, the data on antimicrobial resistance provided by the SFC reduced the carbapenems treatment. CONCLUSIONS: From the theoretical model the Gram stain and the MALDI-TOF results achieved a reduction in the combined treatment. However, the new system tested (SFC), due to the resistance mechanism data provided, not only reduced the combined treatment, it also decreased the prescription of the carbapenems.

Approaching the motional ground state of a 10-kg object.

The motion of a mechanical object, even a human-sized object, should be governed by the rules of quantum mechanics. Coaxing them into a quantum state is, however, difficult because the thermal environment masks any quantum signature of the object's motion. The thermal environment also masks the effects of proposed modifications of quantum mechanics at large mass scales. We prepared the center-of-mass motion of a 10-kilogram mechanical oscillator in a state with an average phonon occupation of 10.8. The reduction in temperature, from room temperature to 77 nanokelvin, is commensurate with an 11 orders-of-magnitude suppression of quantum back-action by feedback and a 13 orders-of-magnitude increase in the mass of an object prepared close to its motional ground state. Our approach will enable the possibility of probing gravity on massive quantum systems.

The exotic legume tree species Acacia holosericea alters microbial soil functionalities and the structure of the arbuscular mycorrhizal community.

The response of microbial functional diversity as well as its resistance to stress or disturbances caused by the introduction of an exotic tree species, Acacia holosericea, ectomycorrhized or not with Pisolithus albus, was examined. The results show that this ectomycorrhizal fungus promotes drastically the growth of this fast-growing tree species in field conditions after 7 years of plantation. Compared to the crop soil surrounding the A. holosericea plantation, this exotic tree species, associated or not with the ectomycorrhizal symbiont, induced strong modifications in soil microbial functionalities (assessed by measuring the patterns of in situ catabolic potential of microbial communities) and reduced soil resistance in response to increasing stress or disturbance (salinity, temperature, and freeze-thaw and wet-dry cycles). In addition, A. holosericea strongly modified the structure of arbuscular mycorrhizal fungus communities. These results show clearly that exotic plants may be responsible for important changes in soil microbiota affecting the structure and functions of microbial communities.

Capsular type distribution and susceptibility to antibiotics of Streptococcus pneumoniae clinical strains isolated from Uruguayan children with systemic infections. Pneumococcus Study Group.

Children under 24 months of age are at high risk for serious infection with Streptococcus pneumoniae but they do not elicit effective immune responses to the currently available capsular polysaccharide vaccines. A polysaccharide protein conjugated vaccine involving the most frequent types has become an urgent need. To produce such a vaccine for Latin America, information on type distribution is required. Recently, Uruguay was 1 of the 6 countries in Latin America where surveillance for invasive pneumococcal infections in children under the age of 5 years was carried out. Seventy percent of the 182 invasive S. pneumoniae isolates were recovered from patients under 24 months of age, and 19% were recovered from infants under 6 months. The 7 most frequent types were 14, 5, 1, 6B, 3, 7F, and 19A; representing 80% of invasive isolates. Twenty-one types were identified, 16 in pneumonia and 14 in meningitis. Resistance to penicillin increased during the study period, from 29% in 1994, to 40% in 1995-1996, mainly because of the spread of type 14 strains resistant to penicillin and trimethoprim/sulphamethoxazol (89% of resistant isolates). The high proportion of systemic pneumococcal infections recorded in patients under 24 months of age and the increasing resistance of these agents to first-choice antibiotics point to an urgent need for a capsular polysaccharide protein conjugated vaccine.

Efficacy of bronchodilators administered by nebulizers versus spacer devices in infants with acute wheezing.

The aim of this study was to compare the response of infants with acute wheezing to treatments with inhaled terbutaline when administered by nebulizer or by metered-dose inhaler and spacer device (MDI-spacer). Thirty-four infants between the ages of 1 and 24 months who were seen in our emergency department for acute wheezing were studied in a double-blind, randomized trial. The participants received two treatments of terbutaline at 20-min intervals, either by a nebulizer (2 mg/dose in 2.8 mL of 0.9% saline solution) or by an MDI-spacer device (0.5 mg/dose). The outcome measure was a clinical score, based on respiratory rate, degree of wheezing, retractions, degree of cyanosis, color, and pulse oximetry data measured before treatment, 20 min after the first treatment, and again 20 min after the second treatment. There was no difference in the rate of improvement in the clinical score between infants who received terbutaline by nebulizer and those who received it by MDI-spacer. We conclude that MDI-spacers and nebulizers are equally effective means of delivering beta-2 agonists to infants and small children with acute wheezing.

[Diagnostic utility of radiography in head trauma: a critical review of the literature]. / Utilidad diagnóstica de la radiografía en el traumatismo craneal. Una revisión crítica de la bibliografía.

INTRODUCTION: The indication of distinct imaging studies in pediatric head trauma, and especially the use of skull radiography, is controversial. OBJECTIVE: To assess the effectiveness of skull radiography in the management of head trauma in pediatric patients. To do this, we aimed to determine the predictive value of this procedure in detecting intracranial injuries, independently of patients' symptoms and clinical examination. MATERIAL AND METHODS: We performed a review of the medical literature (MEDLINE) and of other resources available for searching biomedical information. Studies limited to pediatric patients (0-18 years old) that provided information on the diagnostic utility of skull radiography in head injury were selected. The source and characteristics of the populations studied and potential design limitations were taken into account. RESULTS: Twelve original studies were selected, three of which were performed in children younger than two years old. Differences were found in the origin of the sample populations, the prevalence of intracranial injury and skull fracture, the severity of the trauma included, and in the criteria for performing imaging tests. CONCLUSIONS: Because of the limited comparability of the articles, the usefulness of skull radiography was difficult to assess. Although the use of this technique is accepted in some circumstances in patients younger than two years old, the data obtained assign little value to the systematic use of radiography to assess head trauma in pediatric patients. Head computed tomography is indicated when symptoms or signs of possible neurological injury are present.

[Extracapsular cataract extraction and implantation in the capsular sac during vitrectomy in diabetics]. / Extraction extracapsulaire du cristallin et implantation dans le sac capsulaire au cours de la vitrectomie chez le diabétique.

Removal of the lens is often performed during pars plana vitrectomy for complications of proliferative diabetic retinopathy, but correction of aphakia often remains unsatisfactory. Some authors have reported posterior chamber intraocular lens implantation during pars plana vitrectomy in diabetic patients who presented with coexisting cataract and vitreoretinal complications from proliferative diabetic retinopathy. Some patients were operated by pars plana lensectomy and vitrectomy followed by posterior chamber intraocular lens implantation in the ciliary sulcus, others by extracapsular extraction, posterior chamber intraocular lens implantation in the ciliary sulcus, and pars plana vitrectomy. Other authors have described phacoemulsification through the limbus, pars plana vitrectomy and implantation in the capsular bag in one operation in various indications, including complications of proliferative diabetic retinopathy. We inserted a posterior chamber intraocular lens into the capsular bag in 18 eyes of 16 patients with complications of proliferative diabetic retinopathy after extracapsular cataract extraction and pars plana vitrectomy in a single session. A standard extracapsular cataract extraction was performed before pars plana vitrectomy. Sufficient anterior capsule was left in place in order to facilitate implantation in the capsular bag after pars plana vitrectomy. The anterior chamber was filled with sodium hyaluronate in order to maintain anterior chamber depth, corneal clarity, and good mydriasis during the continuation of the procedure. A standard three port pars plana vitrectomy was performed in all cases. After closure of superior sclerotomies, superior corneal incision was partially reopened, an intraocular lens specifically designed for the capsular bag with an optic size of 7 mm was inserted, and the corneal incision was closed with interrupted 10/0 sutures.(ABSTRACT TRUNCATED AT 250 WORDS)

[Pulmonary complications during parenteral feeding via percutaneous silicon catheters]. / Complicaciones pulmonares durante la nutrición parenteral con catéteres siliconados percutáneos.

Percutaneous fine bore silicone central catheters are frequently used in sick full term newborns and in low birth weight premature infants; although their use has some risks. We report two cases of pleural effusion in two prematures of 34 and 33 weeks gestation and birth weight of 1,510 and 1,650 g, respectively; and one case neumonitis in a newborn of a 38 weeks gestation and 2,730 g birth weight. All of them have in common same initial clinical sign: increase mucus secretion of the upper airway a few hours after the beginning of parenteral nutrition using the type of catheter mentioned with the tip abnormally located in pulmonary artery. These complications are probably related to endothelial injury of very slow flow vessels due to the high osmolarity and low pH of the parenteral solutions used; which probably, in turn, produce thrombosis and vascular perforation, and/or extravasation. We suggest to suspect a pulmonary artery abnormally located catheter in patients receiving parenteral nutrition who increase upper airway mucus secretion. The rapid correction of the position would prevent major complications.

[Peribulbar anesthesia in surgery of the vitreous body and retina]. / L'anesthésie péribulbaire dans la chirurgie vitréorétinienne.

Peribulbar anaesthesia was used in 40 patients undergoing vitreoretinal surgery; two injections of a mixture of bupivacaine 0.5% and hyaluronidase were performed in the lower and the upper eyelid. Results were judged very satisfactory in 38 of these 40 cases, for anaesthesia as well as for akinesia; no local or systemic complications were observed. Peribulbar anaesthesia is one of the methods of choice, because of its safety; it seems well appropriate for vitreoretinal surgery, provided that its indications are judicious.

Emergence of KPC-producing Klebsiella pneumoniae in Uruguay: infection control and molecular characterization.

We describe the first outbreak of Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-KP), the infection control measures adopted and the shift in resistance patterns of isolates during antibiotic treatment. The ST258 KPC-KP strain exhibited a multiresistant antibiotic phenotype including co-resistance to gentamycin, colistin and tigecycline intermediate susceptibility. Isolates before and after treatment had different behaviour concerning their antibiotic susceptibility and the population analysis profile study. A progressive increase in the aminoglycosides (acquiring amicacin resistance) and ß-lactam MICs, and a decreased susceptibility to fosfomycin was observed throughout the administration of combined antimicrobial regimens including meropenem. A high meropenem resistance KPC-KP homogeneous population (MIC 256 Jg/mL), could arise from the meropenem heterogeneous low-level resistance KPC-KP population (MIC 8 Jg/mL), by the selective pressure of the prolonged meropenem therapy. The kpc gene was inserted in a Tn4401 isoform a, and no transconjugants were detected. The core measures adopted were successful to prevent evolution towards resistance dissemination.

Genetic diversity of symbiotic Bradyrhizobium elkanii populations recovered from inoculated and non-inoculated Acacia mangium field trials in Brazil.

Acacia mangium is a legume tree native to Australasia. Since the eighties, it has been introduced into many tropical countries, especially in a context of industrial plantations. Many field trials have been set up to test the effects of controlled inoculation with selected symbiotic bacteria versus natural colonization with indigenous strains. In the introduction areas, A. mangium trees spontaneously nodulate with local and often ineffective bacteria. When inoculated, the persistence of inoculants and possible genetic recombination with local strains remain to be explored. The aim of this study was to describe the genetic diversity of bacteria spontaneously nodulating A. mangium in Brazil and to evaluate the persistence of selected strains used as inoculants. Three different sites, several hundred kilometers apart, were studied, with inoculated and non-inoculated plots in two of them. Seventy-nine strains were isolated from nodules and sequenced on three housekeeping genes (glnII, dnaK and recA) and one symbiotic gene (nodA). All but one of the strains belonged to the Bradyrhizobium elkanii species. A single case of housekeeping gene transfer was detected among the 79 strains, suggesting an extremely low rate of recombination within B. elkanii, whereas the nodulation gene nodA was found to be frequently transferred. The fate of the inoculant strains varied depending on the site, with a complete disappearance in one case, and persistence in another. We compared our results with the sister species Bradyrhizobium japonicum, both in terms of population genetics and inoculant strain destiny.

Responses of soil microbial catabolic diversity to arbuscular mycorrhizal inoculation and soil disinfection.

Although it is usually admitted that arbuscular mycorrhizal (AM) fungi are key components in soil bio-functioning, little is known on the response of microbial functional diversity to AM inoculation. The aims of the present study were to determine the influence of Glomus intraradices inoculum densities on plant growth and soil microflora functional diversity in autoclaved soil or non-disinfected soil. Microbial diversity of soil treatments was assessed by measuring the patterns of in situ catabolic potential of microbial communities. The soil disinfection increased sorghum growth, but lowered catabolic evenness (4.8) compared to that recorded in the non-disinfected soil (6.5). G. intraradices inoculation induced a higher plant growth in the autoclaved soil than in the non-disinfected soil. This AM effect was positively related to inoculum density. Catabolic evenness and richness were positively correlated with the number of inoculated AM propagules in the autoclaved soil, but negatively correlated in the non-disinfected soil. In addition, after soil disinfection and AM inoculation, these microbial functionality indicators had higher values than in the autoclaved or in the non-disinfected soil without AM inoculation. These results are discussed in relation to the ecological influence of AM inoculation, with selected fungal strains and their associated microflora on native soil microbial activity.

Improvement of Cupressus atlantica Gaussen growth by inoculation with native arbuscular mycorrhizal fungi.

AIMS: The study aimed to determine whether inoculation with native arbuscular mycorrhizal (AM) fungi could improve survival and growth of seedlings in degraded soils of Morocco. METHODS AND RESULTS: Soil samples were collected from the rhizosphere of Cupressus atlantica trees in the N'Fis valley (Haut Atlas, Morocco). AM spores were extracted from the soil, identified and this mixture of native AM fungi was propagated on maize for 12 weeks on a sterilized soil to enrich the fungal inoculum. Then C. atlantica seedlings were inoculated with and without (control) mycorrhizal maize roots, cultured in glasshouse conditions and further, transplanted into the field. The experiment was a randomized block design with one factor and three replication blocks. The results showed that a high AM fungal diversity was associated with C. atlantica; native AM fungi inoculation was very effective on the growth of C. atlantica seedlings in glasshouse conditions and this plant growth stimulation was maintained for 1 year after outplanting. CONCLUSIONS: Inoculation of C. atlantica with AM fungi increased growth and survival in greenhouse and field. SIGNIFICANCE AND IMPACT OF THE STUDY: The data indicate that use of native species of AM fungi may accelerate reforestation of degraded soils. Further studies have to be performed to determine the persistence of these mycorrhizae for a longer period of plantation and to measure the effects of this microbial inoculation on soil biofunctioning.

Ectomycorrhizal symbiosis enhanced the efficiency of inoculation with two Bradyrhizobium strains and Acacia holosericea growth.

Two strains of Bradyrhizobium sp., Aust 13C and Aust 11C, were dually or singly inoculated with an ectomycorrhizal fungus, Pisolithus albus to assess the interactions between ectomycorrhizal symbiosis and the nodulation process in glasshouse conditions. Sequencing of strains Aust 13C and Aust 11C confirmed their previous placement in the genus Bradyrhizobium. After 4 months' culture, the ectomycorrhizal symbiosis promoted plant growth and the nodulation process of both Bradyrhizobium strains, singly or dually inoculated. PCR/RFLP analysis of the nodules randomly collected in each treatment with Aust 13C and/or Aust 11C: (1) showed that all the nodules exhibited the same patterns as those of the Bradyrhizobium strains, and (2) did not detect contaminant rhizobia. When both Bradyrhizobium isolates were inoculated together, but without P. albus IR100, Aust 11C was recorded in 13% of the treated nodules compared to 87% for Aust 13C, whereas Aust 11C and Aust 13C were represented in 20 and 80% of the treated nodules, respectively, in the ectomycorrhizal treatment. Therefore Aust 13C had a high competitive ability and a great persistence in soil. The presence of the fungus did not significantly influence the frequencies of each Bradyrhizobium sp. root nodules. Although the mechanisms remain unknown, these results showed that the ectomycorrhizal and biological nitrogen-fixing symbioses were very dependent on each other. From a practical point of view, the role of ectomycorrhizal symbiosis is of great importance to N2 fixation and, consequently, these kinds of symbiosis must be associated in any controlled inoculation.

Founder-effect speciation theory: failure of experimental corroboration.

The theory of founder-effect speciation proposes that colonization by very few individuals of an empty habitat favors rapid genetic changes and the evolution of a new species. We report here the results obtained in a 10-year-long and large-scale experiment with Drosophila pseudoobscura designed to test the theory. In our experimental protocol, populations are established with variable numbers of very few individuals and allowed to expand greatly for several generations until conditions of severe competition for resources are reached and the population crashes. A few random survivors are then taken to start a new population expansion and thus initiate a new cycle of founding events, population flushes, and crashes. Our results provide no support for the theories proposing that new species are very likely to appear as by-products of founder events.