Constraints on primordial black holes from observation of stars in dwarf galaxies

We propose a way to constrain the primordial black hole (PBH) abundance in the range of PBH masses $m$ around $10^{20}$g based on their capture by Sun-like stars in dwarf galaxies, with subsequent star destruction. We calculate numerically the probability of a PBH capture by a star at the time of its formation in an environment typical of dwarf galaxies. Requiring that no more than a fraction $\xi$ of stars in a dwarf galaxy is destroyed by PBHs translates into an upper limit on the PBH abundance. For the parameters of Triangulum II and $\xi=0.5$ we find that no more than $\sim 30\%$ of DM can consist of PBHs in the mass range $10^{18} - \text{(a few)}\times 10^{21}$g. The constraints depend strongly on the parameter $\xi$ and may significantly improve if smaller values of $\xi$ are established from observations. An accurate determination of $\xi$ from dwarf galaxy modeling is thus of major importance.Comment: 5 pages, 2 figure

Post Conviction Legal Aid in County Jails: A Model Law Student Counseling Program

Authors: Peter Van Name Esser, et al

Post Conviction Legal Aid in County Jails: A Model Law Student Counseling Program

Authors: Peter Van Name Esser, et al

Recent Development in IR Sensor Technology for Monitoring Subsea Methane Discharge

Recently developed methane sensors, based on infrared (IR) absorption technology, were successfully utilized for subsea methane release measurements. Long-term investigation of methane emissions (fluid flux determination) from natural methane seeps in the Hikurangi Margin offshore New Zealand were performed by using seafloor lander technology. Small centimeter-sized seep areas could be sampled at the seafloor by video-guided lander deployment. In situ sensor measurements of dissolved methane in seawater could be correlated with methane concentrations measured in discrete water samples after lander recovery. High backscatter flares determined by lander-based Acoustic Doppler Current Profiler (ADCP) measurement indicate bubble release from the seafloor. Highest methane concentrations determined by the IR sensor coincided with periods of high ADCP backscatter signals. The high fluid release cannot be correlated with tidal changes only. However, this correlation is possible with variability in spatial bubble release, sudden outbursts, and tidal changes in more quiescent seepage phases. A recently developed IR sensor (2,000 m depth-rated) with a detection limit for methane of about 1 ppm showed good linearity in the tested concentration range and an acceptable equilibration time of 10 min. The sensor was successfully operated offshore Santa Barbara by a small work-class ROV at a natural methane seep (Farrar Seep). High background methane concentration of 50 nmol L−1 was observed in the coastal water, which increases up to 560 nmol L−1 in dissolved methane plumes south of the seepage area. ROV- and lander-based sensor deployments have proven the applicability of IR sensor technology for the determination of subsea methane release rates and plume distribution. The wide concentration range, low detection limit, and its robust detection unit enable this technology for both subsea leak detection and oceanographic trace gas investigations

Tomographic reconstruction with non-linear diagonal estimators

In tomographic reconstruction, the inversion of the Radon transform in the presence of noise is numerically unstable. Reconstruction estimators are studied where the regularization is performed by a thresholding in a wavelet or wavelet packet decomposition. These estimators are efficient and their optimality can be established when the decomposition provides a near-diagonalization of the inverse Radon transform operator and a compact representation of the object to be recovered. Several new estimators are investigated in different decomposition. First numerical results already exhibit a strong metrical and perceptual improvement over current reconstruction methods. These estimators are implemented with fast non-iterative algorithms, and are expected to outperform Filtered Back-Projection and iterative procedures for PET, SPECT and X-ray CT devices

Regularization in tomographic reconstruction using thresholding estimators

In tomographic medical devices such as SPECT or PET cameras, image reconstruction is an unstable inverse problem, due to the presence of additive noise. A new family of regularization methods for reconstruction, based on a thresholding procedure in wavelet and wavelet packet decompositions, is studied. This approach is based on the fact that the decompositions provide a near-diagonalization of the inverse Radon transform and of the prior information on medical images. An optimal wavelet packet decomposition is adaptively chosen for the specific image to be restored. Corresponding algorithms have been developed for both 2-D and full 3-D reconstruction. These procedures are fast, non-iterative, flexible, and their performance outperforms Filtered Back-Projection and iterative procedures such as OS-EM

De-noising SPECT/PET Images Using Cross-Scale Regularization

De-noising of SPECT and PET images is a challenging task due to the inherent low signal-to-noise ratio of acquired data. Wavelet based multi-scale denoising methods typically apply thresholding operators on sub-band coefficients to eliminate noise components in spatial-frequency space prior to reconstruction. In the case of high noise levels, detailed scales of sub-band images are usually dominated by noise which cannot be easily removed using traditional thresholding schemes. To address this issue, a cross-scale regularization scheme is introduced, which takes into account cross-scale coherence of structured signals. Preliminary results show promising performance in denoising clinical SPECT and PET images for liver and brain studies. Wavelet thresholding was also compared to denoising with a brushlet expansion. The proposed regularization scheme eliminates the need for threshold parameter settings, making the denoising process less tedious and suitable for clinical practice

Identifying the Drivers Behind the Dissemination of Online Misinformation: A Study on Political Attitudes and Individual Characteristics in the Context of Engaging With Misinformation on Social Media

The increasing dissemination of online misinformation in recent years has raised the question which individuals interact with this kind of information and what role attitudinal congruence plays in this context. To answer these questions, we conduct surveys in six countries (BE, CH, DE, FR, UK, and US) and investigate the drivers of the dissemination of misinformation on three noncountry specific topics (immigration, climate change, and COVID-19). Our results show that besides issue attitudes and issue salience, political orientation, personality traits, and heavy social media use increase the willingness to disseminate misinformation online. We conclude that future research should not only consider individual’s beliefs but also focus on specific user groups that are particularly susceptible to misinformation and possibly caught in social media “fringe bubbles.

Frequency of Sexual Problems and Related Psychosocial Characteristics in Cancer Patients—Findings From an Epidemiological Multicenter Study in Germany

Background: Multimodal cancer treatments are often associated with sexual problems. Identifying patients with sexual problems could help further elucidate serious issues with their sexuality and thus promote or maintain patients’ sexual health. We aimed to assess the occurrence of sexual problems in patients across different tumor locations and to explore associated sociodemographic, medical and psychosocial factors. Methods: We included 3,677 cancer patients (mean age 58 years, age range 18– 75 years, 51.4% women) from a large epidemiological multicenter study in Germany on average 13.5 months after cancer diagnosis. The occurrence and frequency of sexual problems were assessed via a binary item on the problem checklist of the Distress Thermometer (DT). Controlled associations of these problems with sociodemographic, medical and psychosocial factors including distress (DT), anxiety (GAD-7), depression (PHQ-9), quality of life (EORTC-QLQ-C30), and social support (SSUK-8) are analyzed using logistic regression analysis. Results: We found that 31.8% of patients reported sexual problems, with a significant higher proportion in men (40.5%) compared to women (23.7%), OR 2.35, 95% CI [1.80– 3.07] and a higher proportion in patients with a partner (35.6%) compared to those without a partner (3.5%), OR 2.83, 95% CI [2.17–3.70]. Tumor location was associated with occurrence of sexual problems: patients with cancer, affecting the male genital organs had the highest chance for sexual problems, OR 2.65, 95% CI [1.18–3.95]. There was no significant difference in the occurrence of sexual problems between age groups OR 0.99, 95% CI [2.13–3.53] and type of therapy (e.g., operation OR 0.91, 95% CI [0.72–1.15]). Sexual problems were further associated with elevated levels of anxiety, OR 1.05, 95% CI [1.02–1.10], less social support, OR 0.93, 95% CI [0.90–0.97] and lower quality of life in terms of impaired functioning (e.g., social function, OR 0.99, 95% CI [0.99–1.00]). Conclusions: Sexual problems are commonly reported by patients. Male patients and those living with a partner are more likely to report sexual problems. Sexual problems are associated with different aspects of well-being. The findings imply the practical relevance to screen for sexual problems among patients and identified groups that should be particularly monitored

The anomalous Hall effect in non-collinear antiferromagnetic Mn3_{3}NiN thin films

We have studied the anomalous Hall effect (AHE) in strained thin films of the frustrated antiferromagnet Mn$_{3}$NiN. The AHE does not follow the conventional relationships with magnetization or longitudinal conductivity and is enhanced relative to that expected from the magnetization in the antiferromagnetic state below $T_{\mathrm{N}} = 260$\,K. This enhancement is consistent with origins from the non-collinear antiferromagnetic structure, as the latter is closely related to that found in Mn$_{3}$Ir and Mn$_{3}$Pt where a large AHE is induced by the Berry curvature. As the Berry phase induced AHE should scale with spin-orbit coupling, yet larger AHE may be found in other members of the chemically flexible Mn$_{3}A$N structure