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  1. Abstract

    We present our photometric search for potential nuclear star clusters (NSCs) in ultra-diffuse galaxies (UDGs) as an extension of the SMUDGes catalog. We identify 325 SMUDGes galaxies with NSCs and, from the 144 with existing distance estimates, identify 33 NSC hosts as UDGs (μ0,g≥ 24 mag arcsec−2,re≥ 1.5 kpc). The SMUDGes with NSCs lie on the galaxy red sequence, satisfy the relationship between NSC and host galaxy stellar masses, have a mean NSC stellar mass fraction of 0.02 but reach as high as 0.1, have NSCs that are displaced from the host center with a standard deviation of 0.10re, and weakly favor higher-density environments. All of these properties are consistent with previous results from higher surface brightness galaxy samples, allowing for at most a relatively weak dependence of NSC behavior on host galaxy surface brightness.

     
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  2. Minimally Invasive Surgeries can benefit from having miniaturized sensors on surgical graspers to provide additional information to the surgeons. In this work, a 6 mm ultrasound transducer was added to a surgical grasper, intended to measure acoustic properties of the tissue. However, the ultrasound sensor has a ringing artifact arising from the decaying oscillation of its piezo element, and at short travel distances, the artifact blends with the acoustic echo. Without a method to remove the artifact from the blended signal, this makes it impossible to measure one of the main characteristics of an ultrasound waveform – Time of Flight. In this paper, six filtering methods to clear the artifact from the ultrasound waveform were compared: Bandpass filter, Adaptive Least Mean Squares (LMS) filter, Spectrum Suppression (SPS), Recurrent Neural Network (RNN), Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU). Following each filtering method, four time of flight extraction methods were compared: Magnitude Threshold, Envelope Peak Detection, Cross-correlation and Short-time Fourier Transform (STFT). The RNN with Cross-correlation method pair was shown to be optimal for this task, performing with the root mean square error of 3.6 %. 
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    Free, publicly-accessible full text available July 18, 2024
  3. Abstract

    The evolution of the hominin hand has been widely linked to the use and production of flaked stone tool technologies. After the earliest handheld flake tools emerged, shifts in hominin hand anatomy allowing for greater force during precision gripping and ease when manipulating objects in-hand are observed in the fossil record. Previous research has demonstrated how biometric traits, such as hand and digit lengths and precision grip strength, impact functional performance and ergonomic relationships when using flake and core technologies. These studies are consistent with the idea that evolutionary selective pressures would have favoured individuals better able to efficiently and effectively produce and use flaked stone tools. After the advent of composite technologies during the Middle Stone Age and Middle Palaeolithic, fossil evidence reveals differences in hand anatomy between populations, but there is minimal evidence for an increase in precision gripping capabilities. Furthermore, there is little research investigating the selective pressures, if any, impacting manual anatomy after the introduction of hafted composite stone technologies (‘handles’). Here we investigated the possible influence of tool-user biometric variation on the functional performance of 420 hafted Clovis knife replicas. Our results suggest there to be no statistical relationships between biometric variables and cutting performance. Therefore, we argue that the advent of hafted stone technologies may have acted as a ‘performance equaliser’ within populations and removed (or reduced) selective pressures favouring forceful precision gripping capabilities, which in turn could have increased the relative importance of cultural evolutionary selective pressures in the determination of a stone tool’s performance.

     
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  4. Abstract

    Elaborate and skilled movements of the body have been selected in a variety of species as courtship and rivalry signals. One roadblock in studying these behaviors has been a lack of resources for understanding how they evolved at the genetic level. The Bornean rock frog (Staurois parvus) is an ideal species in which to address this issue. Males wave their hindlimbs in a “foot-flagging” display when competing for mates. The evolution of foot flagging in S. parvus and other species is accompanied by increases in the expression of the androgen receptor gene within its neuromuscular system, but it remains unclear what genetic or transcriptional changes are associated with this behavioral phenotype. We have now assembled the genome of S. parvus, resulting in 3.98 Gbp of 22,402 contigs with an N50 of 611,229 bp. The genome will be a resource for finding genes related to the physiology underlying foot flagging and to adaptations of the neuromuscular system. As a first application of the genome, we also began work in comparative genomics and differential gene expression analysis. We show that the androgen receptor is diverged from other anuran species, and we identify unique expression patterns of genes in the spinal cord and leg muscle that are important for axial patterning, cell specification and morphology, or muscle contraction. This genome will continue to be an important tool for future -omics studies to understand the evolution of elaborate signaling behaviors in this and potentially related species.

     
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  5. Free, publicly-accessible full text available May 22, 2024
  6. Digitalization shapes the ways of learning, working, and entertainment. The Internet, which enables us to connect and socialize is evolving to become the metaverse, a post-reality universe, enabling virtual life parallel to reality. In addition to gaming and entertainment, industry and academia have noticed the metaverse’s benefits and possibilities. For industry, the metaverse is the enabler of the future digital workplace, and for academia, digital learning spaces enable realistic virtual training environments. A connection bridging the virtual world with physical production systems is required to enable digital workplaces and digital learning spaces. In this publication, extended reality–digital twin to real use cases are presented. The presented use cases utilize extended reality as high-level user interfaces and digital twins to create a bridge between virtual environments and robotic systems in industry, academia, and underwater exploration.

     
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    Free, publicly-accessible full text available June 1, 2024
  7. Stably stratified roughness sublayer flows are ubiquitous yet remain difficult to represent in models and to interpret using field experiments. Here, continuous high‐frequency potential temperature profiles from the forest floor up to 6.5 times the canopy height observed with distributed temperature sensing (DTS) are used to link eddy topology to roughness sublayer stability correction functions and coupling between air layers within and above the canopy. The experiments are conducted at two forest stands classified as hydrodynamically sparse and dense. Near‐continuous profiles of eddy sizes (length scales) and effective mixing lengths for heat are derived from the observed profiles using a novel conditional sampling approach. The approach utilizes potential temperature isoline fluctuations from a statically stable background state. The transport of potential temperature by an observed eddy is assumed to be conserved (adiabatic movement) and we assume that irreversible heat exchange between the eddy and the surrounding background occurs along the (vertical) periphery of the eddy. This assumption is analogous to Prandtl's mixing‐length concept, where momentum is transported rapidly vertically and then equilibrated with the local mean velocity gradient. A distinct dependence of the derived length scales on background stratification, height above ground, and canopy characteristics emerges from the observed profiles. Implications of these findings for (1) the failure of Monin–Obukhov similarity in the roughness sublayer and (2) above‐canopy flow coupling to the forest floor are examined. The findings have practical applications in terms of analysing similar DTS data sets with the proposed approach, modelling roughness sublayer flows, and interpreting nocturnal eddy covariance measurements above tall forested canopies. 
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  8. Abstract

    We have uncovered a role for the promyelocytic leukemia (PML) gene and novel PML-like DEDDh exonucleases in the maintenance of genome stability through the restriction of LINE-1 (L1) retrotransposition in jawed vertebrates. Although the mammalian PML protein forms nuclear bodies, we found that the spotted gar PML ortholog and related proteins in fish function as cytoplasmic DEDDh exonucleases. In contrast, PML proteins from amniote species localized both to the cytoplasm and formed nuclear bodies. We also identified the PML-like exon 9 (Plex9) genes in teleost fishes that encode exonucleases. Plex9 proteins resemble TREX1 but are unique from the TREX family and share homology to gar PML. We also characterized the molecular evolution of TREX1 and the first non-mammalian TREX1 homologs in axolotl. In an example of convergent evolution and akin to TREX1, gar PML and zebrafish Plex9 proteins suppressed L1 retrotransposition and could complement TREX1 knockout in mammalian cells. Following export to the cytoplasm, the human PML-I isoform also restricted L1 through its conserved C-terminus by enhancing ORF1p degradation through the ubiquitin-proteasome system. Thus, PML first emerged as a cytoplasmic suppressor of retroelements, and this function is retained in amniotes despite its new role in the assembly of nuclear bodies.

     
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  9. Abstract

    In Europe, the increase in temperatures caused by climate change has been particularly fast in the cold season. Although the magnitude of this change is relatively well known, less research has been done on how the increase of temperatures is manifested in different large‐scale weather types, called weather regimes. For example, one could expect that the weather patterns in which air is flowing from the rapidly‐warming Arctic would have warmed faster than other weather patterns in recent decades. Here we show that such an asymmetric warming actually occurs in the four Euro‐Atlantic weather regimes. In northern Europe, the weather regime which is typically associated with cold airmasses from the Arctic (NAO–) has warmed about 25% faster than the cold‐season days on average, and about 60% faster than the regime where the air flows from the North Atlantic (NAO+). Consequently, the weather regime that on average brings the coldest weather is warming the fastest in a large part of northern Europe. In contrast, the weather regime that typically brings the warmest weather has warmed the slowest, especially in the continental Europe. Our results provide a new perspective on the reported decrease of sub‐seasonal temperature variability.

     
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