Generation of intense isolated attosecond pulses at 100 eV

Originally limited to big facilities, nonlinear optics experiments in the extreme ultraviolet (XUV) spectral region with table-top systems are becoming a reality. These fundamentally different sources arise from a process known as high-harmonic generation (HHG). In this process, intense mid-IR to UV radiation is converted into the XUV to soft x-rays spectral region when interacting with a gas medium. The broad bandwidth supported by this process additionally allows the isolation of pulses with durations in the attosecond regime. However, given the low conversion efficiency of the HHG process, reaching the necessary XUV intensities to probe nonlinear effects has proven to be a challenging task. The initial investigations in this direction have been realized with photon energies up to 50 eV, by successfully scaling the XUV pulse energy through the use of multi-terawatt driving lasers. In this thesis, the generation and application of intense attosecond XUV-pulses in the 100 eV spectral region is presented. The XUV pulse energy increase is fundamentally enabled thanks to the development of a 16 TW optical-parametric synthesizer based on a two-color pumping technique, which provides pulse durations below two optical cycles. The achieved pulse energy, short pulse duration and the possibility to independently measure the carrier-envelope phase (CEP), makes this laser system a suitable driver of an XUV attosecond source. Through a careful energy scaling scheme, pulse energies above 20 nJ are routinely achieved in a spectrum spanning from 70 to 130 eV. A continuous spectral region is observed in single-shot between 100-130 eV for the appropriate CEP. This allows the isolation of attosecond pulses through spectral filtering. In addition to these high energies and broadband spectra, the reproducibility and long-term stability of the XUV beam makes it suitable for its use towards applications. As a proof-of-principle experiment, the XUV beam is focused to a measured beam size smaller than 3.1 micrometers,where the intensity is estimated to be above 10e13 W/cm2. At focus, the generation of Xe4+ and Xe5+ ions through the absorption of two photons is demonstrated. This is the first realization of such a measurement at these photon energies with a HHG source, paving the way to future attosecond time-resolved nonlinear spectroscopy of inner-shell electron dynamics

Generation of intense isolated attosecond pulses at 100 eV

Originally limited to big facilities, nonlinear optics experiments in the extreme ultraviolet (XUV) spectral region with table-top systems are becoming a reality. These fundamentally different sources arise from a process known as high-harmonic generation (HHG). In this process, intense mid-IR to UV radiation is converted into the XUV to soft x-rays spectral region when interacting with a gas medium. The broad bandwidth supported by this process additionally allows the isolation of pulses with durations in the attosecond regime. However, given the low conversion efficiency of the HHG process, reaching the necessary XUV intensities to probe nonlinear effects has proven to be a challenging task. The initial investigations in this direction have been realized with photon energies up to 50 eV, by successfully scaling the XUV pulse energy through the use of multi-terawatt driving lasers. In this thesis, the generation and application of intense attosecond XUV-pulses in the 100 eV spectral region is presented. The XUV pulse energy increase is fundamentally enabled thanks to the development of a 16 TW optical-parametric synthesizer based on a two-color pumping technique, which provides pulse durations below two optical cycles. The achieved pulse energy, short pulse duration and the possibility to independently measure the carrier-envelope phase (CEP), makes this laser system a suitable driver of an XUV attosecond source. Through a careful energy scaling scheme, pulse energies above 20 nJ are routinely achieved in a spectrum spanning from 70 to 130 eV. A continuous spectral region is observed in single-shot between 100-130 eV for the appropriate CEP. This allows the isolation of attosecond pulses through spectral filtering. In addition to these high energies and broadband spectra, the reproducibility and long-term stability of the XUV beam makes it suitable for its use towards applications. As a proof-of-principle experiment, the XUV beam is focused to a measured beam size smaller than 3.1 micrometers,where the intensity is estimated to be above 10e13 W/cm2. At focus, the generation of Xe4+ and Xe5+ ions through the absorption of two photons is demonstrated. This is the first realization of such a measurement at these photon energies with a HHG source, paving the way to future attosecond time-resolved nonlinear spectroscopy of inner-shell electron dynamics

A Study Comparing Pre-Ingested L-Leucine and L-Isoleucine on Glycemic Responses in Healthy Inactive Adults: Preliminary Data.

Background The co-ingestion of amino acids with a glucose drink has been shown to blunt the elevated post-prandial glucose response. Though not entirely clear, some suggest amino acids will facilitate an incretin-driven insulin response that improves glucose sensitivity. Therefore, the purpose of this study is to examine the “priming” effect of pre-ingested amino acids on glycemic control in healthy inactive adults. We present here some preliminary data from 7 adults. Hypothesis We hypothesize that the pre-ingested amino acids would attenuate the post-prandial rise in glucose during a 75 g glucose tolerance test. Methods To test this, seven healthy adults (Females: n =4, Males: n=3, Age 27.17 ± 4.7 y; Height 165.84 ± 9.53 cm; Weight 82.47 ± 14.63 kg; BMI 30.14 ± 7.54 kg/m2; Lean body mass (LBM) 56.83 ± 20.56 kg; Fasting blood glucose (FBG) 87.43 ± 5.29 mg/dL) completed four trials in a randomized, single blinded fashion. The four trials required participants to ingest either Leucine (LEU), L-Isoleucine (ISO), an equal combination of LEU/ISO combined and lastly a control. Each treatment was ingested 30-min prior to a 2 h 75-g oral glucose tolerance test. The amino acid drink (200 mL) was standardized by the participant LBM (0.3g/kg) while the control consisted of inert stevia and non-amino acid ingredients found in equal amounts as other treatment mixtures (3.54 g). Venous blood samples were taken at baseline, and at 10, 30, 40, 60, 90, 120, and 150-min post-treatment and 75 g glucose drink. Because data collection is ongoing, the researchers are still blinded to the composition of the amino acid drinks and thus results are presented as: Red A, Green B, Yellow C, and control (White D). Plasma glucose (GLU) was analyzed using a YSI 2900 analyzer (Yellow Springs Instruments) and insulin (INS), glucagon (GCG), glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1) concentrations were quantified by fluorescent bead-based technology (MAGPIX, Luminex xMAP technology). A 2-way RMANOVA was used to assess glucose data (Graphpad Software). Results Pre-ingestion of amino acid had no significant treatment effect on GLU compared to control (P = 0.5912). Currently, only 2 individuals have been analyzed for insulin, C-peptide, glucagon, GLP-1Active, and GIPTotal. However, we observed early and promising, non-statistical supported differences in concentrations between trials of insulin (Red A, Yellow C \u3e Green B, White D), GLP-1Active (Red A, Green B, Yellow C \u3e White D), and GIPTotal (Red A \u3e Green B, Yellow C, White D). Conclusion Based on these preliminary results, it appears that pre-ingestion of an amino acid drink does not influence glucose control in healthy and inactive young adults. It remains to be seen if pre-ingestion of the amino acids LEU and ISO, have any definitive effect on incretin secretion or subsequent insulin and glucagon responses

The zika virus disease: An overview

The zika virus, another re-emerging Flavivirus transmitted to humans by mosquitoes, is responsible for the most recent fever outbreak in the Americas and the Pacific, starting in 2015. The immunologically naïve population in the Americas favors the spread of epidemics. The zika fever is characterized by febrile illness, malaise, conjunctivitis and a maculopapular rash. Similar to other arboviroses recently spread in the Americas, there is no specific or effective antiviral therapy and vaccines are still in trials. The only effective preventive measures consist of individual protection against mosquito bites and vector control. This febrile illness increases the epidemiological and public health challenge existing in America, where the population is already fighting against dengue and chikungunya fever. Disease prevention is important due to the economic burden it entails. The fact of sexual and transfusion virus transmission is a great challenge to overcome. Doctors need to distinguish between dengue, chikungunya and other diseases to give a successful treatment and prevent the disease spreading

“Troublemaking,” “Making Trouble,” and “Making It” Through Institutionalized Schooling: Critical Pedagogy as a Transformational Exodus

This article examines the quality of public schooling in primarily low socio-economic status (SES) areas of El Paso, Texas and reflects on the dismal realities established by the hegemonic social order

Quantum transport in quantum networks and photosynthetic complexes at the steady state

Recently, several works have analysed the efficiency of photosynthetic complexes in a transient scenario and how that efficiency is affected by environmental noise. Here, following a quantum master equation approach, we study the energy and excitation transport in fully connected networks both in general and in the particular case of the Fenna-Matthew-Olson complex. The analysis is carried out for the steady state of the system where the excitation energy is constantly "flowing" through the system. Steady state transport scenarios are particularly relevant if the evolution of the quantum system is not conditioned on the arrival of individual excitations. By adding dephasing to the system, we analyse the possibility of noise-enhancement of the quantum transport.Comment: 10 pages, single column, 6 figures. Accepted for publication in Plos On

Base-specific mutational intolerance near splice sites clarifies the role of nonessential splice nucleotides

Variation in RNA splicing (i.e., alternative splicing) plays an important role in many diseases. Variants near 5' and 3' splice sites often affect splicing, but the effects of these variants on splicing and disease have not been fully characterized beyond the two "essential" splice nucleotides flanking each exon. Here we provide quantitative measurements of tolerance to mutational disruptions by position and reference allele-alternative allele combinations. We show that certain reference alleles are particularly sensitive to mutations, regardless of the alternative alleles into which they are mutated. Using public RNA-seq data, we demonstrate that individuals carrying such variants have significantly lower levels of the correctly spliced transcript, compared to individuals without them, and confirm that these specific substitutions are highly enriched for known Mendelian mutations. Our results propose a more refined definition of the "splice region" and offer a new way to prioritize and provide functional interpretation of variants identified in diagnostic sequencing and association studies.Peer reviewe

Association of accelerometer-derived sleep measures with lifetime psychiatric diagnoses : A cross-sectional study of 89,205 participants from the UK Biobank

Funding Information: The authors acknowledge Milos Milic for data curation assistance. MW and SJT acknowledge support from the Kavli Foundation, Krembil Foundation, CAMH Discovery Fund, the McLaughlin Foundation, NSERC (RGPIN-2020-05834 and DGECR-2020-00048) and CIHR (NGN-171423). DF is supported by the Michael and Sonja Koerner Foundation New Scientist Program, Krembil Foundation, CAMH Discovery Fund, and the McLaughlin Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. This research was conducted under the auspices of UK Biobank application 61530, ?Multimodal subtyping of mental illness across the adult lifespan through integration of multi-scale whole-person phenotypes?. The authors acknowledge Milos Milic for data curation assistance. This research was conducted under the auspices of UK Biobank application 61530, ?Multimodal subtyping of mental illness across the adult lifespan through integration of multi-scale whole-person phenotypes.? Publisher Copyright: Copyright: © 2021 Wainberg et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background Sleep problems are both symptoms of and modifiable risk factors for many psychiatric disorders. Wrist-worn accelerometers enable objective measurement of sleep at scale. Here, we aimed to examine the association of accelerometer-derived sleep measures with psychiatric diagnoses and polygenic risk scores in a large community-based cohort. Methods and findings In this post hoc cross-sectional analysis of the UK Biobank cohort, 10 interpretable sleep measures—bedtime, wake-up time, sleep duration, wake after sleep onset, sleep efficiency, number of awakenings, duration of longest sleep bout, number of naps, and variability in bedtime and sleep duration—were derived from 7-day accelerometry recordings across 89,205 participants (aged 43 to 79, 56% female, 97% self-reported white) taken between 2013 and 2015. These measures were examined for association with lifetime inpatient diagnoses of major depressive disorder, anxiety disorders, bipolar disorder/mania, and schizophrenia spectrum disorders from any time before the date of accelerometry, as well as polygenic risk scores for major depression, bipolar disorder, and schizophrenia. Covariates consisted of age and season at the time of the accelerometry recording, sex, Townsend deprivation index (an indicator of socioeconomic status), and the top 10 genotype principal components. We found that sleep pattern differences were ubiquitous across diagnoses: each diagnosis was associated with a median of 8.5 of the 10 accelerometer-derived sleep measures, with measures of sleep quality (for instance, sleep efficiency) generally more affected than mere sleep duration. Effect sizes were generally small: for instance, the largest magnitude effect size across the 4 diagnoses was β = −0.11 (95% confidence interval −0.13 to −0.10, p = 3 × 10−56, FDR = 6 × 10−55) for the association between lifetime inpatient major depressive disorder diagnosis and sleep efficiency. Associations largely replicated across ancestries and sexes, and accelerometry-derived measures were concordant with self-reported sleep properties. Limitations include the use of accelerometer-based sleep measurement and the time lag between psychiatric diagnoses and accelerometry. Conclusions In this study, we observed that sleep pattern differences are a transdiagnostic feature of individuals with lifetime mental illness, suggesting that they should be considered regardless of diagnosis. Accelerometry provides a scalable way to objectively measure sleep properties in psychiatric clinical research and practice, even across tens of thousands of individuals.Peer reviewe

Fano resonances in saturable waveguide arrays

We study a waveguide array with an embedded nonlinear saturable impurity. We solve the impurity problem in closed form and find the nonlinear localized modes. Next, we consider the scattering of a small-amplitude plane wave by a nonlinear impurity mode, and discover regions in parameter space where transmission is fully suppressed. We relate these findings with Fano resonances and propose this setup as a mean to control the transport of light across the array.Comment: 3 pages, 4 figures, submitted to Optics Letter

Stylolites and stylolite networks as primary controls on the geometry and distribution of carbonate diagenetic alterations

There is ongoing debate on whether stylolites act as barriers, conduits, or play no role in fluid transport. This problem can be tackled by examining the spatial and temporal relationships between stylolites and other diagenetic products at multiple scales. Using the well-known Lower Cretaceous Benicàssim case study area (Maestrat Basin, E. Spain), we provide new field and petrographic observations of how bedding-parallel stylolites can influence different diagenetic processes during basin evolution. The results reveal that stylolites can serve as baffles or inhibitors for different carbonate diagenetic reactions, and act as fronts for dolomitization, dolomite recrystallization and dolomite calcitization processes. Anastomosing stylolites that pre-date burial dolomitization probably acted as a collective baffle for dolomitization fluids in the study area, resulting in stratabound replacement geometries at the metre-to-kilometre scale. The dolomitization front coincides with stylolites, and can be traced along consecutive anastomosing ones. Such anastomosing stylolites are typical of mud-dominated facies that characterize limestone-dolostone transition zones. Conversely, dolostone bodies tend to correspond to more grain-dominated facies characterized by parallel (non-anastomosing) stylolites. Stylolites subsequently acted as fluid flow conduits and barriers when the burial and stress conditions changed. Stylolitic porosity enhanced by dissolution within dolostones close to faults appears filled with saddle dolomite riming the stylolite pore, and high-temperature blocky calcite cements filling the remaining porosity. The fluids responsible for these reactions were likely released from below at high pressure, causing hydraulic brecciation, and were channelised through stylolites, which acted as fluid conduits. Stylolites are also found acting as baffles for subsequent dolomite calcitization reactions during meteoric diagenesis and occasionally appear filled with iron oxides likely released by calcitization. This example demonstrates how the same type of stylolites (bedding-parallel) can act as barriers/inhibitors and/or conduits for different types of diagenetic reactions through time, and how important it is to consider their collective role when they form networks