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 gamma-ray survey of the Galactic Center (GC) region, i.e., the Inner Galaxy Survey, at very high energies (& GSIM;100 GeV) performed with the H.E.S.S. array of five ground-based Cherenkov telescopes. No significant gamma-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 (sigma v). 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 (sigma v) values of 3.7 x 10-26 cm3 s-1 for 1.5 TeV DM mass in the W+W- annihilation channel, and 1.2 x 10-26 cm3 s-1 for 0.7 TeV DM mass in the tau+tau- annihilation channel. With the H.E.S.S. Inner Galaxy Survey, ground-based gamma-ray observations thus probe (sigma v) values expected from thermal-relic annihilating TeV DM particles.
Previous research has shown that speakers have superior memory of past referents within a conversation compared to listeners because they invest more cognitive effort into language planning and ...execution than listeners (i.e., speaking benefit; Yoon, et al., 2016; 2021). This phenomenon is consistent with the generation effect in memory literature which suggests that memory is enhanced when items are actively generated than when they are passively received. Less explored is the nature of speaking benefit on memory when language production may be challenging, which may be the case for adults who stutter (AWS). Many people who stutter can anticipate when they are about to stutter and thus may try to avoid the upcoming stutter by, for example, switching words. This may require increased attention and cognitive resources in language production. This hypothesis needs empirical investigation, which was the purpose of this study.The goal of our research was to understand the cognitive mechanisms that support language production in AWS. We aimed to examine how the cognitive effort of language production among AWS affects memory representations of past referents relative to adults who do not stutter (AWNS). Thirty-two AWS and 64 AWNS participated in the study. AWNS were further divided into a control group (N=32) and an attention-divided group (N=32). The attention-divided group was designed to simulate the divided attentional demand AWS often experience in language production due to sound or word avoidance. Thus, there were a total of three groups, including 1) AWS, 2) AWNS, and 3) AWNS with an attention-divided task (AWNS-AD). They participated in a referential communication task in which participants and their partner (i.e., experimenter) collaboratively completed a task-based conversation. Participants’ role (speaking vs. listening) and the discourse context (contrast vs. non-contrast) were manipulated in the task. Participants were asked to describe a target picture among the four pictures on the screen to the experimenter during a block of the trials (i.e., speaking) and to identify the picture that the experimenter described for them during another block of the trials (i.e., listening).Our primary interest was the interplay between the referential expressions produced in the communication task and the accuracy in the subsequent memory test. We hypothesized that if AWS required more cognitive resources to avoid a moment of stuttering during language production, then they would show a decreased speaking benefit in their memory compared to AWNS. Because of the sound avoidances assumed in both the AWS and AWNS-AD groups, we hypothesized that memory performance would be similar between AWS and AWNS-AD.In the memory test, we analyzed the accuracy of target items (i.e., the items described during the communication task). The significant main effect of Role (speaker vs. listener) suggests that speakers have superior memory of past referents compared to listeners, consistent with previous findings (Yoon, et al., 2016; 2021). A significant interaction between Group (AWNS-AD vs. AWS) and Role (speaker vs. listener) was driven by a significant speaking benefit in the AWNS-AD but not in the AWS group. The AWNS-AD group had a significantly higher accuracy for memory of past referents as speakers vs. listeners in conversation, whereas AWS showed no difference in their role as a speaker vs. listener for memory of past referents. In other words, AWS’ memory was equally accurate when speaking and listening.In conclusion, all participants in our study were sensitive to the local discourse context, demonstrating more use of modifiers when there was a related image present vs. absent. Interestingly, AWS generally produced more modifiers regardless of local context than participants in the other two groups. Further, in the memory test, participants in both AWNS and AWNS-AD showed a speaking benefit that they remembered past referents better when speaking vs. listening. However, we observed a novel effect that AWS did not benefit from speaking in their memory. This result suggests that AWS may invest more cognitive efforts in both language production and comprehension compared to AWNS. Given that the memory performance of AWS was better than that of AWNS-AD, the possibility that AWS avoid specific difficult sound or words does not require additional cognitive resources in their processes of language production. These preliminary findings lay the foundation for future individual differences research in which we examine how each individual’s strategy to avoid stuttering may interact with their language production and memory.
ABSTRACT
We report on a search for persistent radio emission from the one-off fast radio burst (FRB) 20190714A, as well as from two repeating FRBs, 20190711A and 20171019A, using the MeerKAT radio ...telescope. For FRB 20171019A, we also conducted simultaneous observations with the High-Energy Stereoscopic System (H.E.S.S.) in very high-energy gamma rays and searched for signals in the ultraviolet, optical, and X-ray bands. For this FRB, we obtain a UV flux upper limit of $1.39 \times 10^{-16}~{\rm erg\, cm^{-2}\, s^{-1}}$Å−1, X-ray limit of $\sim 6.6 \times 10^{-14}~{\rm erg\, cm^{-2}\, s^{-1}}$ and a limit on the very high energy gamma-ray flux $\Phi (E\gt 120\, {\rm GeV}) \lt 1.7\times 10^{-12}\, \mathrm{erg\, cm^{-2}\, s^{-1}}$. We obtain a radio upper limit of ∼15 $\mu$Jy beam−1 for persistent emission at the locations of both FRBs 20190711A and 20171019A with MeerKAT. However, we detected an almost unresolved (ratio of integrated flux to peak flux is ∼1.7 beam) radio emission, where the synthesized beam size was ∼ 8 arcsec size with a peak brightness of $\sim 53\, \mu$Jy beam−1 at MeerKAT and $\sim 86\, \mu$Jy beam−1 at e-MERLIN, possibly associated with FRB 20190714A at z = 0.2365. This represents the first detection of persistent continuum radio emission potentially associated with a (as-yet) non-repeating FRB. If the association is confirmed, one of the strongest remaining distinction between repeaters and non-repeaters would no longer be applicable. A parallel search for repeat bursts from these FRBs revealed no new detections down to a fluence of 0.08 Jy ms for a 1 ms duration burst.
PSR B1259–63/LS 2883 is a gamma-ray binary system that hosts a pulsar in an eccentric orbit, with a 3.4 yr period, around an O9.5Ve star (LS 2883). At orbital phases close to periastron passages, the ...system radiates bright and variable non-thermal emission, for which the temporal and spectral properties of this emission are, for now, poorly understood. In this regard, very high-energy (VHE) emission is especially useful to study and constrain radiation processes and particle acceleration in the system. We report on an extensive VHE observation campaign conducted with the High Energy Stereoscopic System, comprised of approximately 100 h of data taken over five months, from t p − 24 days to t p + 127 days around the system’s 2021 periastron passage (where t p is the time of periastron). We also present the timing and spectral analyses of the source. The VHE light curve in 2021 is consistent overall with the stacked light curve of all previous observations. Within the light curve, we report a VHE maximum at times coincident with the third X-ray peak first detected in the 2021 X-ray light curve. In the light curve – although sparsely sampled in this time period – we see no VHE enhancement during the second disc crossing. In addition, we see no correspondence to the 2021 GeV flare in the VHE light curve. The VHE spectrum obtained from the analysis of the 2021 dataset is best described by a power law of spectral index Γ = 2.65 ± 0.04 stat ± 0.04 sys , a value consistent with the spectral index obtained from the analysis of data collected with H.E.S.S. during the previous observations of the source. We report spectral variability with a difference of ΔΓ = 0.56 ± 0.18 stat ± 0.10 sys at 95% confidence intervals, between sub-periods of the 2021 dataset. We also detail our investigation into X-ray/TeV and GeV/TeV flux correlations in the 2021 periastron passage. We find a linear correlation between contemporaneous flux values of X-ray and TeV datasets, detected mainly after t p + 25 days, suggesting a change in the available energy for non-thermal radiation processes. We detect no significant correlation between GeV and TeV flux points, within the uncertainties of the measurements, from ∼ t p − 23 days to ∼ t p + 126 days. This suggests that the GeV and TeV emission originate from different electron populations.
Abstract
We report on the observations of four well-localized binary black hole (BBH) mergers by the High Energy Stereoscopic System (H.E.S.S.) during the second and third observing runs of Advanced ...LIGO and Advanced Virgo, O2 and O3. H.E.S.S. can observe 20 deg
2
of the sky at a time and follows up gravitational-wave (GW) events by “tiling” localization regions to maximize the covered localization probability. During O2 and O3, H.E.S.S. observed large portions of the localization regions, between 35% and 75%, for four BBH mergers (GW170814, GW190512_180714, GW190728_064510, and S200224ca). For these four GW events, we find no significant signal from a pointlike source in any of the observations, and we set upper limits on the very high energy (>100 GeV)
γ
-ray emission. The 1–10 TeV isotropic luminosity of these GW events is below 10
45
erg s
−1
at the times of the H.E.S.S. observations, around the level of the low-luminosity GRB 190829A. Assuming no changes are made to how follow-up observations are conducted, H.E.S.S. can expect to observe over 60 GW events per year in the fourth GW observing run, O4, of which eight would be observable with minimal latency.
Abstract
Primordial Black Holes (PBHs) are hypothetical black holes predicted to have been formed from density fluctuations in the early Universe.
PBHs with an initial mass around 10
14
–10
15
g are ...expected to end their evaporation at present times in a burst of particles and very-high-energy (VHE) gamma rays.
Those gamma rays may be detectable by the High Energy Stereoscopic System (H.E.S.S.), an array of imaging atmospheric Cherenkov telescopes.
This paper reports on the search for evaporation bursts of VHE gamma rays with H.E.S.S., ranging from 10 to 120 seconds, as expected from the final stage of PBH evaporation and using a total of 4816 hours of observations.
The most constraining upper limit on the burst rate of local PBHs is
2000 pc
-3
yr
-1
for a burst interval of 120 seconds, at the 95% confidence level. The implication of these measurements for PBH dark matter are also discussed.
Galaxy clusters contain an abundance of dark matter making them attractive laboratories for indirect DM searches. This work details a search for signals of pair annihilation from WIMP dark matter in ...the GeV gamma ray regime. We perform this search in five low
z
z
and high galactic latitude galaxy clusters (Centaurus, Coma, Virgo, Perseus and Fornax); using nearly 12 years of Fermi/LAT data. Through the non-detection of this characteristic signal, we derive constraints on the annihilation cross-section of DM pair annihilation into the
b\overline{b}
b
b
‾
,
W^+W^-
W
+
W
−
and
\gamma\gamma
γ
γ
channels. The limits obtained are of a comparable magnitude to those of recently derived from Fermi/LAT observations of dwarf spheroidal galaxies.
Purpose Selected patients with bladder cancer with pelvic lymphadenopathy (cN1-3) are treated with induction chemotherapy followed by radical cystectomy. However, the data on clinical outcomes in ...these patients are limited. In this study we assess pathological and survival outcomes in patients with cN1-3 disease treated with induction chemotherapy and radical cystectomy. Materials and Methods Data were collected on patients from 19 North American and European centers with cT1-4aN1-N3 urothelial carcinoma who received chemotherapy followed by radical cystectomy between 2000 and 2013. The primary end points were pathological complete (pT0N0) and partial (pT1N0 or less) response rates, with overall survival as a secondary end point. Logistic regression and Cox proportional hazard ratios were used for multivariate analysis of factors predicting these outcomes. Results The total of 304 patients had clinical evidence of lymph node involvement (cN1-N3). Methotrexate/vinblastine/doxorubicin/cisplatin was used in 128 (42%), gemcitabine/cisplatin in 132 (43%) and other regimens in 44 (15%) patients. The pN0 rate was 48% (cN1—56%, cN2—39%, cN3—39%, p=0.03). The complete and partial pathological response rates for the entire cohort were 14.5% and 27%, respectively. The estimated median overall survival time for the cohort was 22 months (IQR 8.0, 54). On Cox regression analysis overall survival was associated with pN0, negative surgical margins, removal of 15 or more pelvic nodes and cisplatin therapy. Conclusions Complete pathological nodal response can be achieved in a proportion of patients with cN1-3 disease receiving induction chemotherapy. The best survival outcomes are observed in male patients on cisplatin regimens with subsequent negative radical cystectomy margins and complete nodal response (pN0) with excision of 15 or more pelvic nodes.
Purpose We assessed survival dependent on pathological response after neoadjuvant chemotherapy in a large multicenter patient cohort, with a particular focus on the difference between the absence of ...residual cancer (pT0) and the presence of only nonmuscle invasive residual cancer (pTa, pTis, pT1). Materials and Methods We retrospectively reviewed records of patients with urothelial cancer who received neoadjuvant chemotherapy and underwent radical cystectomy at 19 contributing institutions from 2000 to 2013. Patients with cT2-4aN0M0 and eventual pN0 disease were selected for this analysis. Estimated overall survival was compared between patients with pT0 and pTa/Tis/T1 disease. A multivariable Cox proportional hazards regression model for overall survival was generated to evaluate hazard ratios for variables of interest. Results Of 1,543 patients treated with neoadjuvant chemotherapy and radical cystectomy during the study period 257 had pT0N0 and 207 had pTa/Tis/T1N0 disease. The Kaplan-Meier mean estimates of overall survival for pT0 and pTa/Tis/T1 cases were 186.7 months (95% CI 145.9–227.6, median 241.1) and 138 months (95% CI 118.2–157.8, median 187.4), respectively (p=0.58). In the Cox proportional hazards regression model for overall survival pTa/Tis/T1N0 status (HR 0.36, 95% CI 0.23–0.67) and pT0N0 status (HR 0.28, 95% CI 0.17–0.47) compared to pT2N0 pathology, positive surgical margin (HR 1.75, 95% CI 1.07–2.86), and receiving a methotrexate, vinblastine, doxorubicin and cisplatin regimen compared to an “other” regimen (HR 0.45, 95% CI 0.27–0.76) were predictors of overall survival. Conclusions pTa/Tis/T1N0 and pT0N0 stage on the final cystectomy specimen are strong predictors of survival in patients treated with neoadjuvant chemotherapy and radical cystectomy. We did not discern a statistically significant difference in overall survival when comparing these 2 end points.
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