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Abstract We have searched for radio pulsations toward 49 Fermi Large Area Telescope (LAT) 1FGL Catalogγ-ray sources using the Green Bank Telescope at 350 MHz. We detected 18 millisecond pulsars (MSPs) in blind searches of the data; 10 of these were discoveries unique to our survey. 16 are binaries, with eight having short orbital periodsP_B< 1 day. No radio pulsations from young pulsars were detected, although three targets are coincident with apparently radio-quietγ-ray pulsars discovered in LAT data. Here, we give an overview of the survey and present radio andγ-ray timing results for the 10 MSPs discovered. These include the only isolated MSP discovered in our survey and six short-P_Bbinary MSPs. Of these, three have very-low-mass companions (M_c≪ 0.1M_⊙) and hence belong to the class of black widow pulsars. Two have more massive, nondegenerate companions with extensive radio eclipses and orbitally modulated X-ray emission consistent with the redback class. Significantγ-ray pulsations have been detected from nine of the discoveries. This survey and similar efforts suggest that the majority of Galacticγ-ray sources at high Galactic latitudes are either MSPs or relatively nearby nonrecycled pulsars, with the latter having on average a much smaller radio/γ-ray beaming ratio as compared to MSPs. It also confirms that past surveys suffered from an observational bias against finding short-P_BMSP systems. 

Roughly 85% of mammalian herbivore species in southern Kenya were replaced by smaller, more adaptable species at some time between 400,000 years ago (400ka) and 500 ka. While this major taxonomic turnover has been attributed to a shift to more a more arid and variable climate and tectonic activity, we wondered if a particularly abrupt shift, a “tipping point,” in climate at some time between 400 and 500 ka was the cause. We analyzed the highest resolution paleoclimate record available in East Africa, Lake Malawi drill core MAL05-1B, for organic geochemical proxies, including branched glycerol dialkyl glycerol tetraethers (GDGTs) and leaf wax deuterium isotopic records to develop the temperature and precipitation history, respectively, between 600 and 200 ka. Results show an abrupt temperature increase of ~6°C occurring in less than 3000 years during Glacial Termination V, which is the Marine Isotope Stage (MIS) 12 to MIS 11 transition at ~430 ka. Surprisingly, even more intense warming occurred during Glacial Termination VI around 510 ka. Notably, these deglacial warmings coincide with enriched leaf wax deuterium isotopic values suggesting a shift to more arid conditions in interglacials MIS 13 and 11 than in glacials MIS 14 and 12, respectively. These changes from cold/wet glacials to warm/dry interglacials contrast with the cool/dry pattern of the Last Glacial Maximum (LGM) in East Africa that transitioned to a warm/wet Holocene. We propose that the major warming and drying during Termination V in the Malawi basin represents a significant abrupt change that impacted much of eastern Africa around 430 ka and was a likely driver of the major faunal turnover noted in the region. 

We report the first detection of coherent elastic neutrino-nucleus scattering (CEvNS) on natural germanium, measured at the Spallation Neutron Source at Oak Ridge National Laboratory. The Ge-Mini detector of the COHERENT collaboration employs large-mass, low-noise, high-purity germanium spectrometers, enabling excellent energy resolution, and an analysis threshold of 1.5 keV electron-equivalent ionization energy. We observe an on-beam excess of ${20.6}_{-6.3}^{+7.1}$counts with a total exposure of 10.22 GWhkg, and we reject the no-CEvNS hypothesis with $3.9\sigma$significance. The result agrees with the predicted standard model of particle physics signal rate within $2\sigma$. Published by the American Physical Society2025 

Using the newly introduced ``occupation kernels,'' the present manuscript develops an approach to dynamic mode decomposition (DMD) that treats continuous time dynamics, without discretization, through the Liouville operator. The technical and theoretical differences between Koopman based DMD for discrete time systems and Liouville based DMD for continuous time systems are highlighted, which includes an examination of these operators over several reproducing kernel Hilbert spaces. 

This paper introduces robustness verification for semantic segmentation neural networks (in short, semantic segmentation networks [SSNs]), building on and extending recent approaches for robustness verification of image classification neural networks. Despite recent progress in developing verification methods for specifications such as local adversarial robustness in deep neural networks (DNNs) in terms of scalability, precision, and applicability to different network architectures, layers, and activation functions, robustness verification of semantic segmentation has not yet been considered. We address this limitation by developing and applying new robustness analysis methods for several segmentation neural network architectures, specifically by addressing reachability analysis of up-sampling layers, such as transposed convolution and dilated convolution. We consider several definitions of robustness for segmentation, such as the percentage of pixels in the output that can be proven robust under different adversarial perturbations, and a robust variant of intersection-over-union (IoU), the typical performance evaluation measure for segmentation tasks. Our approach is based on a new relaxed reachability method, allowing users to select the percentage of a number of linear programming problems (LPs) to solve when constructing the reachable set, through a relaxation factor percentage. The approach is implemented within NNV, then applied and evaluated on segmentation datasets, such as a multi-digit variant of MNIST known as M2NIST. Thorough experiments show that by using transposed convolution for up-sampling and average-pooling for down-sampling, combined with minimizing the number of ReLU layers in the SSNs, we can obtain SSNs with not only high accuracy (IoU), but also that are more robust to adversarial attacks and amenable to verification. Additionally, using our new relaxed reachability method, we can significantly reduce the verification time for neural networks whose ReLU layers dominate the total analysis time, even in classification tasks. 

Tellurium (Te) stable isotope measurements have the potential to serve as tracers of Te mobility and redox conditions in modern and ancient environments. Here, we present a method to measure Te isotope ratios by MC-ICP-MS utilizing a hydride generation system to efficiently deliver Te to the plasma, in combination with a 120 Te– 124 Te double spike. This approach allows for precise δ 130 Te/ 126 Te (2 σ : 0.09‰) measurements while using less than 8.75 ng of natural Te. Although hydride generation methods usually produce higher sensitivity than more conventional methods, for Te, the sensitivity is similar, on our instrument, to that achieved using a desolvating nebulizer. Nonetheless, hydride generation has an advantageous ability to exclude interfering elements such as Ba and allow analysis of samples without chemical separation of Te in some cases. We also demonstrate successfully a modified ion exchange procedure to separate various matrix components and isobaric interferences from Te in natural sediments. Analyses of multiple digestions of USGS standard reference materials, mine tailings, ancient sediments, and soils utilizing this approach show the largest spread in terrestrial Te isotopic composition to date (δ 130 Te/ 126 Te ∼ 1.21‰) and a lack of detectable mass-independent fractionation. 

We consider the potential for a 10 kg undoped cryogenic CsI detector operating at the Spallation Neutron Source to measure coherent elastic neutrino-nucleus scattering and its sensitivity to discover new physics beyond the standard model (BSM). Through a combination of increased event rate, lower threshold, and good timing resolution, such a detector would significantly improve on past measurements. We considered tests of several BSM scenarios such as neutrino nonstandard interactions and accelerator-produced dark matter. This detector’s performance was also studied for relevant questions in nuclear physics and neutrino astronomy, namely the weak charge distribution of Cs and I nuclei and detection of neutrinos from a core-collapse supernova. Published by the American Physical Society2024