A very-high-energy component deep in the γ-ray burst afterglow.

Gamma-ray bursts (GRBs) are brief flashes of γ-rays and are considered to be the most energetic explosive phenomena in the Universe1. The emission from GRBs comprises a short (typically tens of seconds) and bright prompt emission, followed by a much longer afterglow phase. During the afterglow phase, the shocked outflow-produced by the interaction between the ejected matter and the circumburst medium-slows down, and a gradual decrease in brightness is observed2. GRBs typically emit most of their energy via γ-rays with energies in the kiloelectronvolt-to-megaelectronvolt range, but a few photons with energies of tens of gigaelectronvolts have been detected by space-based instruments3. However, the origins of such high-energy (above one gigaelectronvolt) photons and the presence of very-high-energy (more than 100 gigaelectronvolts) emission have remained elusive4. Here we report observations of very-high-energy emission in the bright GRB 180720B deep in the GRB afterglow-ten hours after the end of the prompt emission phase, when the X-ray flux had already decayed by four orders of magnitude. Two possible explanations exist for the observed radiation: inverse Compton emission and synchrotron emission of ultrarelativistic electrons. Our observations show that the energy fluxes in the X-ray and γ-ray range and their photon indices remain comparable to each other throughout the afterglow. This discovery places distinct constraints on the GRB environment for both emission mechanisms, with the inverse Compton explanation alleviating the particle energy requirements for the emission observed at late times. The late timing of this detection has consequences for the future observations of GRBs at the highest energies.

Relationship between cognition and age at onset of first-episode psychosis: comparative study between adolescents, young adults, and adults.

Psychotic disorders typically manifest from late adolescence to early adulthood, and an earlier onset might be associated with greater symptom severity and a worse long-term prognosis. This study aimed to compare the cognitive characteristics of patients with first-episode psychosis (FEP) by their age at onset. We included 298 patients diagnosed with FEP and classified them as having an early onset (EOS), youth onset (YOS), or adult onset (AOS) based on age limits of ≤ 18 years (N = 61), 19-24 years (N = 121), and ≥ 25 years (N = 116), respectively. Socio-demographic and clinical variables included age at baseline, gender, socio-economic status, antipsychotic medication, DSM-IV diagnoses assessed by clinical semi-structured interview, psychotic symptom severity, and age at onset. Neuropsychological assessment included six cognitive domains: premorbid intelligence, working memory, processing speed, verbal memory, sustained attention, and executive functioning. The EOS group had lower scores than the YOS or AOS groups in global cognition, executive functioning, and sustained attention. Although the scores in the YOS group were intermediate to those in the EOS and AOS groups for most cognitive factors, no statistically significant differences were detected between the YOS and AOS groups. Age at onset results in specific patterns of cognitive interference. Of note, impairment appears to be greater with EOS samples than with either YOS or AOS samples. A longitudinal study with a larger sample size is needed to confirm our findings.

Search for Dark Matter Annihilation Signals in the H.E.S.S. Inner Galaxy Survey.

The central region of the Milky Way is one of the foremost locations to look for dark matter (DM) signatures. We report the first results on a search for DM particle annihilation signals using new observations from an unprecedented γ-ray survey of the Galactic Center (GC) region, i.e., the Inner Galaxy Survey, at very high energies (≳100 GeV) performed with the H.E.S.S. array of five ground-based Cherenkov telescopes. No significant γ-ray excess is found in the search region of the 2014-2020 dataset and a profile likelihood ratio analysis is carried out to set exclusion limits on the annihilation cross section ⟨σv⟩. Assuming Einasto and Navarro-Frenk-White (NFW) DM density profiles at the GC, these constraints are the strongest obtained so far in the TeV DM mass range. For the Einasto profile, the constraints reach ⟨σv⟩ values of 3.7×10^{-26} cm^{3} s^{-1} for 1.5 TeV DM mass in the W^{+}W^{-} annihilation channel, and 1.2×10^{-26} cm^{3} s^{-1} for 0.7 TeV DM mass in the τ^{+}τ^{-} annihilation channel. With the H.E.S.S. Inner Galaxy Survey, ground-based γ-ray observations thus probe ⟨σv⟩ values expected from thermal-relic annihilating TeV DM particles.

Cannabis use influence on peripheral brain-derived neurotrophic factor levels in antipsychotic-naïve first-episode psychosis.

The objective of this study is to determine whether cannabis influences BDNF levels in patients with psychosis (FEP) and healthy volunteers (HV) to help understand the role of BDNF in psychosis. We assessed the association between BDNF and cannabis in a cohort of FEP antipsychotic-naïve patients and HV, whilst controlling for other potential confounding factors. 70 FEP drug-naive patients and 57 HV were recruited. A sociodemographic variable collection, structured clinical interview, weight and height measurement, substance use determination, and blood collection to determine BDNF levels by ELISA analysis were done. In FEP patients, cannabis use was associated with BDNF levels (high cannabis use was associated with lower BDNF levels). Moreover, cannabis use was statistically significantly associated with age (high use of cannabis was associated with younger age). In HV, no relationship between cannabis use and BDNF levels was observed. Otherwise, cannabis use was significantly associated with tobacco use, so that high cannabis users were also high tobacco users. This study showed a different association between cannabis use and BDNF levels in FEP patients compared with HV, particularly, with high doses of cannabis. These findings may help understand the deleterious effects of cannabis in some vulnerable individuals, as well as discrepancies in the literature.

Search for γ-Ray Line Signals from Dark Matter Annihilations in the Inner Galactic Halo from 10 Years of Observations with H.E.S.S.

Spectral lines are among the most powerful signatures for dark matter (DM) annihilation searches in very-high-energy γ rays. The central region of the Milky Way halo is one of the most promising targets given its large amount of DM and proximity to Earth. We report on a search for a monoenergetic spectral line from self-annihilations of DM particles in the energy range from 300 GeV to 70 TeV using a two-dimensional maximum likelihood method taking advantage of both the spectral and spatial features of the signal versus background. The analysis makes use of Galactic center observations accumulated over ten years (2004-2014) with the H.E.S.S. array of ground-based Cherenkov telescopes. No significant γ-ray excess above the background is found. We derive upper limits on the annihilation cross section ⟨σv⟩ for monoenergetic DM lines at the level of 4×10^{-28} cm^{3} s^{-1} at 1 TeV, assuming an Einasto DM profile for the Milky Way halo. For a DM mass of 1 TeV, they improve over the previous ones by a factor of 6. The present constraints are the strongest obtained so far for DM particles in the mass range 300 GeV-70 TeV. Ground-based γ-ray observations have reached sufficient sensitivity to explore relevant velocity-averaged cross sections for DM annihilation into two γ-ray photons at the level expected from the thermal relic density for TeV DM particles.

H.E.S.S. Limits on Linelike Dark Matter Signatures in the 100 GeV to 2 TeV Energy Range Close to the Galactic Center.

A search for dark matter linelike signals iss performed in the vicinity of the Galactic Center by the H.E.S.S. experiment on observational data taken in 2014. An unbinned likelihood analysis iss developed to improve the sensitivity to linelike signals. The upgraded analysis along with newer data extend the energy coverage of the previous measurement down to 100 GeV. The 18 h of data collected with the H.E.S.S. array allow one to rule out at 95% C.L. the presence of a 130 GeV line (at l=-1.5°, b=0° and for a dark matter profile centered at this location) previously reported in Fermi-LAT data. This new analysis overlaps significantly in energy with previous Fermi-LAT and H.E.S.S. RESULTS: No significant excess associated with dark matter annihilations was found in the energy range of 100 GeV to 2 TeV and upper limits on the gamma-ray flux and the velocity weighted annihilation cross section are derived adopting an Einasto dark matter halo profile. Expected limits for present and future large statistics H.E.S.S. observations are also given.

Search for Dark Matter Annihilations towards the Inner Galactic Halo from 10 Years of Observations with H.E.S.S.

The inner region of the Milky Way halo harbors a large amount of dark matter (DM). Given its proximity, it is one of the most promising targets to look for DM. We report on a search for the annihilations of DM particles using γ-ray observations towards the inner 300 pc of the Milky Way, with the H.E.S.S. array of ground-based Cherenkov telescopes. The analysis is based on a 2D maximum likelihood method using Galactic Center (GC) data accumulated by H.E.S.S. over the last 10 years (2004-2014), and does not show any significant γ-ray signal above background. Assuming Einasto and Navarro-Frenk-White DM density profiles at the GC, we derive upper limits on the annihilation cross section ⟨σv⟩. These constraints are the strongest obtained so far in the TeV DM mass range and improve upon previous limits by a factor 5. For the Einasto profile, the constraints reach ⟨σv⟩ values of 6×10^{-26} cm^{3} s^{-1} in the W^{+}W^{-} channel for a DM particle mass of 1.5 TeV, and 2×10^{-26} cm^{3} s^{-1} in the τ^{+}τ^{-} channel for a 1 TeV mass. For the first time, ground-based γ-ray observations have reached sufficient sensitivity to probe ⟨σv⟩ values expected from the thermal relic density for TeV DM particles.

Constraints on an annihilation signal from a core of constant dark matter density around the milky way center with H.E.S.S.

An annihilation signal of dark matter is searched for from the central region of the Milky Way. Data acquired in dedicated on-off observations of the Galactic center region with H.E.S.S. are analyzed for this purpose. No significant signal is found in a total of ∼9 h of on-off observations. Upper limits on the velocity averaged cross section, ⟨σv⟩, for the annihilation of dark matter particles with masses in the range of ∼300 GeV to ∼10 TeV are derived. In contrast to previous constraints derived from observations of the Galactic center region, the constraints that are derived here apply also under the assumption of a central core of constant dark matter density around the center of the Galaxy. Values of ⟨σv⟩ that are larger than 3×10^{-24} cm^{3}/s are excluded for dark matter particles with masses between ∼1 and ∼4 TeV at 95% C.L. if the radius of the central dark matter density core does not exceed 500 pc. This is the strongest constraint that is derived on ⟨σv⟩ for annihilating TeV mass dark matter without the assumption of a centrally cusped dark matter density distribution in the search region.

Spanish adaptation and validation of the Brief Negative Symptoms Scale.

Negative symptoms prevalent in schizophrenia are associated with poor outcome. Developing new instruments to identify new treatments was highlighted at the NIMH-MATRICS Consensus Development Conference on Negative Symptoms. The new Brief Negative Symptoms scale (BNSS) demonstrated strong psychometric properties, but there is a need for validating it in non-English languages. A multi-center study was conducted to validate the Spanish version of the BNSS (BNSS-Sp) in 20 schizophrenia patients, following the original BNSS validation methodology. We found strong inter-rater, test-retest and internal consistency properties (for the total BNSS-Sp, intraclass correlation coefficient=0.97, Pearson's correlation coefficient r=0.95 (p<0.001), Cronbach's alpha=0.98).

Evaluation of the impact of a clinical pathway on the organization of a multidisciplinary dental sleep clinic.

PURPOSE: Clinical pathways are used to organize complex care processes by providing structure and standardization. The multidisciplinary approach of oral appliance (OA) therapy for sleep-disordered breathing (SDB) is a complex and dynamic process suitable for such a structured pathway approach. METHODS: A clinical pathway for patients referred for OA therapy was developed and implemented. The aim of this study was to evaluate the impact of this clinical pathway on the time to delivery of the OA and the organization of the multidisciplinary dental sleep clinic (MDSC). The latter was achieved using the care process self-evaluation tool (CPSET). RESULTS: First, development and implementation of the clinical pathway gave structure and shortened the mean time to delivery by 102 days (240 ± 70 vs. 138 ± 33 days) (Mann-Whitney U: P < 0.001). Second, the CPSET scores were obtained in a cohort of 49 healthcare professionals involved in the pathway. Overall, patient-focused organization received the highest scores (80.5 ± 9.0%), whereas cooperation with primary care received the lowest score (66.7 ± 12.4%). CONCLUSIONS: This is the first project on clinical pathways in OA therapy for SDB. The implementation of the pathway in our MDSC has created a significant shortening of the time to delivery. A first evaluation of the clinical pathway using the CPSET scores indicates that all disciplines involved should be thoroughly informed in an ongoing approach.

Acceleration and transport of relativistic electrons in the jets of the microquasar SS 433.

SS 433 is a microquasar, a stellar binary system that launches collimated relativistic jets. We observed SS 433 in gamma rays using the High Energy Stereoscopic System (H.E.S.S.) and found an energy-dependent shift in the apparent position of the gamma-ray emission from the parsec-scale jets. These observations trace the energetic electron population and indicate that inverse Compton scattering is the emission mechanism of the gamma rays. Our modeling of the energy-dependent gamma-ray morphology constrains the location of particle acceleration and requires an abrupt deceleration of the jet flow. We infer the presence of shocks on either side of the binary system, at distances of 25 to 30 parsecs, and that self-collimation of the precessing jets forms the shocks, which then efficiently accelerate electrons.

A low level of extragalactic background light as revealed by gamma-rays from blazars.

The diffuse extragalactic background light consists of the sum of the starlight emitted by galaxies through the history of the Universe, and it could also have an important contribution from the 'first stars', which may have formed before galaxy formation began. Direct measurements are difficult and not yet conclusive, owing to the large uncertainties caused by the bright foreground emission associated with zodiacal light. An alternative approach is to study the absorption features imprinted on the gamma-ray spectra of distant extragalactic objects by interactions of those photons with the background light photons. Here we report the discovery of gamma-ray emission from the blazars H 2356 - 309 and 1ES 1101 - 232, at redshifts z = 0.165 and z = 0.186, respectively. Their unexpectedly hard spectra provide an upper limit on the background light at optical/near-infrared wavelengths that appears to be very close to the lower limit given by the integrated light of resolved galaxies. The background flux at these wavelengths accordingly seems to be strongly dominated by the direct starlight from galaxies, thus excluding a large contribution from other sources-in particular from the first stars formed. This result also indicates that intergalactic space is more transparent to gamma-rays than previously thought.

Discovery of very-high-energy gamma-rays from the Galactic Centre ridge.

The source of Galactic cosmic rays (with energies up to 10(15) eV) remains unclear, although it is widely believed that they originate in the shock waves of expanding supernova remnants. At present the best way to investigate their acceleration and propagation is by observing the gamma-rays produced when cosmic rays interact with interstellar gas. Here we report observations of an extended region of very-high-energy (> 10(11) eV) gamma-ray emission correlated spatially with a complex of giant molecular clouds in the central 200 parsecs of the Milky Way. The hardness of the gamma-ray spectrum and the conditions in those molecular clouds indicate that the cosmic rays giving rise to the gamma-rays are likely to be protons and nuclei rather than electrons. The energy associated with the cosmic rays could have come from a single supernova explosion around 10(4) years ago.

Time-resolved hadronic particle acceleration in the recurrent nova RS Ophiuchi.

Recurrent novae are repeating thermonuclear explosions in the outer layers of white dwarfs, due to the accretion of fresh material from a binary companion. The shock generated when ejected material slams into the companion star's wind can accelerate particles. We report very-high-energy (VHE; [Formula: see text]) gamma rays from the recurrent nova RS Ophiuchi, up to 1 month after its 2021 outburst, observed using the High Energy Stereoscopic System (H.E.S.S.). The temporal profile of VHE emission is similar to that of lower-energy giga-electron volt emission, indicating a common origin, with a 2-day delay in peak flux. These observations constrain models of time-dependent particle energization, favoring a hadronic emission scenario over the leptonic alternative. Shocks in dense winds provide favorable environments for efficient acceleration of cosmic rays to very high energies.

Gray matter volume deficits and correlation with insight and negative symptoms in first-psychotic-episode subjects.

OBJECTIVE: To determine brain areas reduced in first episode of psychotic subjects and its association with lack of insight and negative symptoms. METHOD: Twenty-one drug naive first-episode subjects and 20 controls underwent a structural MRI scan and were clinically assessed. Optimized voxel-based-morphometry analysis (VBM) was implemented to find between-group differences and correlations between GM volume and: (i) lack of insight and (ii) negative symptoms. RESULTS: Patients showed GM reduction in prefrontal and left temporal areas. A significant correlation was found between insight and GM volume in the cerebellum (corrected P = 0.01), inferior temporal gyrus (corrected P = 0.022), medial superior frontal gyrus (corrected P < 0.001), and inferior frontal gyrus (corrected P = 0.012), as the insight decreased, the volume decreased. Negative symptoms correlated with decreased GM volume at cerebellum (corrected P = 0.037) and frontal inferior regions (corrected P < 0.001), the more negative symptoms, the less volume. CONCLUSION: Our findings support an association between prefrontal, temporal, and cerebellar deficits and lack of insight in schizophrenia and confirm previous findings of GM deficits in patients since the first episode of psychosis.

Revealing x-ray and gamma ray temporal and spectral similarities in the GRB 190829A afterglow.

Gamma-ray bursts (GRBs), which are bright flashes of gamma rays from extragalactic sources followed by fading afterglow emission, are associated with stellar core collapse events. We report the detection of very-high-energy (VHE) gamma rays from the afterglow of GRB 190829A, between 4 and 56 hours after the trigger, using the High Energy Stereoscopic System (H.E.S.S.). The low luminosity and redshift of GRB 190829A reduce both internal and external absorption, allowing determination of its intrinsic energy spectrum. Between energies of 0.18 and 3.3 tera-electron volts, this spectrum is described by a power law with photon index of 2.07 ± 0.09, similar to the x-ray spectrum. The x-ray and VHE gamma-ray light curves also show similar decay profiles. These similar characteristics in the x-ray and gamma-ray bands challenge GRB afterglow emission scenarios.

Search for new bottomlike quark pair decays QQ-->(tW(+)(-))(tW(+)(-)in same-charge dilepton events.

We report the most restrictive direct limits on masses of fourth-generation down-type quarks b{'}, and quarklike composite fermions (B or T{5/3}), decaying promptly to tW{-/+}. We search for a significant excess of events with two same-charge leptons (e, mu), several hadronic jets, and missing transverse energy. An analysis of data from pp collisions with an integrated luminosity of 2.7 fb{-1} collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits m{b{'}}, m{B}>338 GeV/c{2} and m{T{5/3}}>365 GeV/c{2} at 95% confidence level.

High-energy particle acceleration in the shell of a supernova remnant.

A significant fraction of the energy density of the interstellar medium is in the form of high-energy charged particles (cosmic rays). The origin of these particles remains uncertain. Although it is generally accepted that the only sources capable of supplying the energy required to accelerate the bulk of Galactic cosmic rays are supernova explosions, and even though the mechanism of particle acceleration in expanding supernova remnant (SNR) shocks is thought to be well understood theoretically, unequivocal evidence for the production of high-energy particles in supernova shells has proven remarkably hard to find. Here we report on observations of the SNR RX J1713.7 - 3946 (G347.3 - 0.5), which was discovered by ROSAT in the X-ray spectrum and later claimed as a source of high-energy gamma-rays of TeV energies (1 TeV = 10(12) eV). We present a TeV gamma-ray image of the SNR: the spatially resolved remnant has a shell morphology similar to that seen in X-rays, which demonstrates that very-high-energy particles are accelerated there. The energy spectrum indicates efficient acceleration of charged particles to energies beyond 100 TeV, consistent with current ideas of particle acceleration in young SNR shocks.

[New promising caregiver's psychoeducation training program: a Belgian experience in dementing disorders]. / La psychoéducation des accompagnants de patients déments comme nouvelle approche thérapeutique à l'efficacité démontrée.

Facing difficulties due to dementia syndromes, systemic care is necessary. But nevertheless, caregivers are generally lacking in medical welfare. Therapies assessed specifically to caregivers are missing. Amongst these, psychoeducative steps seem to be the strongest effective's one on neuropsychiatrics symptoms. Psychoeducations tend to learn to caregivers to modify their interactions with patients via a better understanding of illnesses and patients. Our training "Pour mieux vivre avec la maladie d'Alzheimer ", done in groups of eight to twelve persons, is constituted of twelve sessions of two hours each. Complete formation includes behavioural and cognitive aspects of the disease and proposes some multidimensional approach which content at least pedagogical, psychological and cognitivo behavioural aspects. We illustrate here with the use of two peculiar cases that our program can reach its objectives. These preliminary results strongly argue for the pursuit and even extension of this kind of caregiver's management.

[Evaluation of our psycho-educative program by participating caregivers]. / Evaluation de notre programme de psychoéducation par les accompagnants de patients déments.

Facing difficulties due to dementia syndromes, systemic care is necessary. Amongst therapies assessed specifically to caregivers, psychoeducative steps seem to be the strongest effective one on neuropsychiatrics symptoms. Psychoeducations tend to teach the caregivers to modify their interactions with patients via a better understanding of illnesses and patients. Our training "Pour mieux vivre avec la maladie d'Alzheimer", applied in groups of eight to twelve persons, consists in twelve sessions of two hours each. To assure the biggest possible availability, we recently incorporated the concomitant coverage of patients into artistic workshops. These sessions of art-therapy realized in parallel to our psychoeducative program will thus be estimated according to the same rigorous methodology. The critical evaluations realized by participants at the end of our program reflect the outcome of our main objective (to teach to modify interactions with the patients) while contributing to the improvement of social contacts and to the learning of calling to existing helps. These preliminary results strongly argue for the pursuit and even extension of this kind of caregiver's management.