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26 results on '"HU, P. K."'

1. Extragalactic fast X-ray transient from a weak relativistic jet associated with a Type Ic-BL supernova

Author

Sun, H., Li, W. -X., Liu, L. -D., Gao, H., Wang, X. -F., Yuan, W., Zhang, B., Filippenko, A. V., Xu, D., An, T., Ai, S., Brink, T. G., Liu, Y., Liu, Y. -Q., Wang, C. -Y., Wu, Q. -Y., Wu, X. -F., Yang, Y., Zhang, B. -B., Zheng, W. -K., Ahumada, T., Dai, Z. -G., Delaunay, J., Elias-Rosa, N., Benetti, S., Fu, S. -Y., Howell, D. A., Huang, Y. -F., Kasliwal, M. M., Karambelkar, V., Stein, R., Lei, W. -H., Lian, T. -Y., Peng, Z. -K., Ridnaia, A. V., Svinkin, D. S., Wang, X. -Y., Wang, A. -L., Wei, D. -M., An, J., Andrews, M., Bai, J. -M, Dai, C. -Y., Ehgamberdiev, S. A., Fan, Z., Farah, J., Feng, H. -C., Fynbo, J. P. U., Guo, W. -J., Guo, Z., Hu, M. -K., Hu, J. -W., Jiang, S. -Q., Jin, J. -J., Li, A., Li, J. -D., Li, R. -Z., Liang, Y. -F., Ling, Z. -X., Liu, X., Mao, J. -R., McCully, C., Mirzaqulov, D., Newsome, M., Gonzalez, E. Padilla, Pan, X., Terreran, G., Tinyanont, S., Wang, B. -T., Wang, L. -Z., Wen, X. -D., Xiang, D. -F., Xue, S. -J., Yang, J., Zhu, Z. -P., Cai, Z. -M., Castro-Tirado, A. J., Chen, F. -S., Chen, H. -L., Chen, T. -X., Chen, W., Chen, Y. -H., Chen, Y. -F., Chen, Y., Cheng, H. -Q., Cordier, B., Cui, C. -Z., Cui, W. -W., Dai, Y. -F., Fan, D. -W., Feng, H., Guan, J., Han, D. -W., Hou, D. -J., Hu, H. -B., Huang, M. -H., Huo, J., Jia, S. -M., Jia, Z. -Q., Jiang, B. -W., Jin, C. -C., Jin, G., Kuulkers, E., Li, C. -K., Li, D. -Y., Li, J. -F., Li, L. -H., Li, M. -S., Li, W., Li, Z. -D., Liu, C. -Z, Liu, H. -Y., Liu, H. -Q., Liu, M. -J., Lu, F. -J., Luo, L. -D., Ma, J., Mao, X., Nandra, K., O'Brien, P., Pan, H. -W., Rau, A., Rea, N., Sanders, J., Song, L. -M., Sun, S. -L., Sun, X. -J., Tan, Y. -Y., Tang, Q. -J., Tao, Y. -H., Wang, H., Wang, J., Wang, L., Wang, W. -X., Wang, Y. -L., Wang, Y. -S., Xiong, D. -R., Xu, H. -T., Xu, J. -J., Xu, X. -P., Xu, Y. -F., Xu, Z., Xue, C. -B., Xue, Y. -L., Yan, A. -L., Yang, H. -N., Yang, X. -T., Yang, Y. -J., Zhang, C., Zhang, J., Zhang, M., Zhang, S. -N., Zhang, W. -D., Zhang, W. -J., Zhang, Y. -H., Zhang, Z., Zhang, Z. -L., Zhao, D. -H., Zhao, H. -S., Zhao, X. -F., Zhao, Z. -J., Zhou, Y. -L., Zhu, Y. -X., and Zhu, Z. -C.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

Massive stars end their life as core-collapse supernovae, amongst which some extremes are Type Ic broad-lined supernovae associated with long-duration gamma-ray bursts (LGRBs) having powerful relativistic jets. Their less-extreme brethren make unsuccessful jets that are choked inside the stars, appearing as X-ray flashes or low-luminosity GRBs. On the other hand, there exists a population of extragalactic fast X-ray transients (EFXTs) with timescales ranging from seconds to thousands of seconds, whose origins remain obscure. Known sources that contribute to the observed EFXT population include the softer analogs of LGRBs, shock breakouts of supernovae, or unsuccessful jets. Here, we report the discovery of the bright X-ray transient EP240414a detected by the Einstein Probe (EP), which is associated with the Type Ic supernova SN 2024gsa at a redshift of 0.401. The X-ray emission evolution is characterised by a very soft energy spectrum peaking at < 1.3 keV, which makes it distinct from known LGRBs, X-ray flashes, or low-luminosity GRBs. Follow-up observations at optical and radio bands revealed the existence of a weak relativistic jet that interacts with an extended shell surrounding the progenitor star. Located on the outskirts of a massive galaxy, this event reveals a new population of explosions of Wolf-Rayet stars characterised by a less powerful engine that drives a successful but weak jet, possibly owing to a progenitor star with a smaller core angular momentum than in traditional LGRB progenitors., Comment: 43 pages, 9 figures, 4 tables, submitted. Comments are welcome

Published
2024

2. Massive stars exploding in a He-rich circumstellar medium $-$ X. Flash spectral features in the Type Ibn SN 2019cj and observations of SN 2018jmt

Author

Wang, Z. -Y., Pastorello, A., Maeda, K., Reguitti, A., Cai, Y. -Z., Howell, D. Andrew, Benetti, S., Buckley, D., Cappellaro, E., Carini, R., Cartier, R., Chen, T. -W., Elias-Rosa, N., Fang, Q. -L., Gal-Yam, A., Gangopadhyay, A., Gromadzki, M., Gan, W. -P., Hiramatsu, D., Hu, M. -K., Inserra, C., McCully, C., Nicholl, M., Olivares, F. E., Pignata, G., Pineda-Garc'ia, J., Pursiainen, M., Ragosta, F., Rau, A., Roy, R., Sollerman, J., Tartaglia, L., Terreran, G., Valerin, G., Wang, Q., Wang, S. -Q., Young, D. R., Aryan, A., Bronikowski, M., Concepcion, E., Galbany, L., Lin, H., Melandri, A., Petrushevska, T., Ramirez, M., Shi, D. -D, Warwick, B., Zhang, J. -J., Wang, B., Wang, X. -F., and Zhu, X. -J.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract

We present optical and near-infrared observations of two Type Ibn supernovae (SNe), SN 2018jmt and SN 2019cj. Their light curves have rise times of about 10 days, reaching an absolute peak magnitude of $M_g$(SN 2018jmt) = $-$19.07 $\pm$ 0.37 and $M_V$(SN 2019cj) = $-$18.94 $\pm$ 0.19 mag, respectively. The early-time spectra of SN 2018jmt are dominated by a blue continuum, accompanied by narrow (600$-$1000 km~s$^{-1}$) He I lines with P-Cygni profile. At later epochs, the spectra become more similar to those of the prototypical SN Ibn 2006jc. At early phases, the spectra of SN 2019cj show flash ionisation emission lines of C III, N III and He II superposed on a blue continuum. These features disappear after a few days, and then the spectra of SN 2019cj evolve similarly to those of SN 2018jmt. The spectra indicate that the two SNe exploded within a He-rich circumstellar medium (CSM) lost by the progenitors a short time before the explosion. We model the light curves of the two SNe Ibn to constrain the progenitor and the explosion parameters. The ejecta masses are consistent with either that expected for a canonical SN Ib ($\sim$ 2 M$_{\odot}$) or those from a massive WR star ($>$ $\sim$ 4 M$_{\odot}$), with the kinetic energy on the order of $10^{51}$ erg. The lower limit on the ejecta mass ($>$ $\sim$ 2 M$_{\odot}$) argues against a scenario involving a relatively low-mass progenitor (e.g., $M_{ZAMS}$ $\sim$ 10 M$_{\odot}$). We set a conservative upper limit of $\sim$0.1 M$_{\odot}$ for the $^{56}$Ni masses in both SNe. From the light curve modelling, we determine a two-zone CSM distribution, with an inner, flat CSM component, and an outer CSM with a steeper density profile. The physical properties of SN 2018jmt and SN 2019cj are consistent with those expected from the core collapse of relatively massive, stripped-envelope (SE) stars., Comment: 28 pages, 19 figures, Accepted for publication in Astronomy & Astrophysics

Published
2024
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3. Proliferation-driven mechanical compression induces signalling centre formation during mammalian organ development

Author

Shroff, Neha Pincha, Xu, Pengfei, Kim, Sangwoo, Shelton, Elijah R, Gross, Ben J, Liu, Yucen, Gomez, Carlos O, Ye, Qianlin, Drennon, Tingsheng Yu, Hu, Jimmy K, Green, Jeremy BA, Campàs, Otger, and Klein, Ophir D

Subjects
Biochemistry and Cell Biology, Biological Sciences, 2.1 Biological and endogenous factors, Animals, Female, Pregnancy, Signal Transduction, Incisor, Cell Differentiation, Mammals, Cell Proliferation, Stress, Mechanical, Medical and Health Sciences, Developmental Biology, Biochemistry and cell biology
Abstract

Localized sources of morphogens, called signalling centres, play a fundamental role in coordinating tissue growth and cell fate specification during organogenesis. However, how these signalling centres are established in tissues during embryonic development is still unclear. Here we show that the main signalling centre orchestrating development of rodent incisors, the enamel knot (EK), is specified by a cell proliferation-driven buildup in compressive stresses (mechanical pressure) in the tissue. Direct mechanical measurements indicate that the stresses generated by cell proliferation are resisted by the surrounding tissue, creating a circular pattern of mechanical anisotropy with a region of high compressive stress at its centre that becomes the EK. Pharmacological inhibition of proliferation reduces stresses and suppresses EK formation, and application of external pressure in proliferation-inhibited conditions rescues the formation of the EK. Mechanical information is relayed intracellularly through YAP protein localization, which is cytoplasmic in the region of compressive stress that establishes the EK and nuclear in the stretched anisotropic cells that resist the pressure buildup around the EK. Together, our data identify a new role for proliferation-driven mechanical compression in the specification of a model signalling centre during mammalian organ development.

Published
2024

4. Myosin II mediates Shh signals to shape dental epithelia via control of cell adhesion and movement

Author

Du, Wei, Verma, Adya, Ye, Qianlin, Du, Wen, Lin, Sandy, Yamanaka, Atsushi, Klein, Ophir D, and Hu, Jimmy K

Subjects
Biochemistry and Cell Biology, Biological Sciences, Dental/Oral and Craniofacial Disease, 1.1 Normal biological development and functioning, Animals, Mice, Hedgehog Proteins, Cell Adhesion, Signal Transduction, Myosin Type II, Cell Movement, Epithelium, Morphogenesis, Tooth, Epithelial Cells, Proto-Oncogene Proteins c-akt, Gene Expression Regulation, Developmental, Genetics, Developmental Biology
Abstract

The development of ectodermal organs begins with the formation of a stratified epithelial placode that progressively invaginates into the underlying mesenchyme as the organ takes its shape. Signaling by secreted molecules is critical for epithelial morphogenesis, but how that information leads to cell rearrangement and tissue shape changes remains an open question. Using the mouse dentition as a model, we first establish that non-muscle myosin II is essential for dental epithelial invagination and show that it functions by promoting cell-cell adhesion and persistent convergent cell movements in the suprabasal layer. Shh signaling controls these processes by inducing myosin II activation via AKT. Pharmacological induction of AKT and myosin II can also rescue defects caused by the inhibition of Shh. Together, our results support a model in which the Shh signal is transmitted through myosin II to power effective cellular rearrangement for proper dental epithelial invagination.

Published
2024

7. Disentangling top-down drivers of mortality underlying diel population dynamics of Prochlorococcus in the North Pacific Subtropical Gyre

Author

Beckett, Stephen J., Demory, David, Coenen, Ashley R., Casey, John R., Dugenne, Mathilde, Follett, Christopher L., Connell, Paige, Carlson, Michael C. G., Hu, Sarah K., Wilson, Samuel T., Muratore, Daniel, Rodriguez-Gonzalez, Rogelio A., Peng, Shengyun, Becker, Kevin W., Mende, Daniel R., Armbrust, E. Virginia, Caron, David A., Lindell, Debbie, White, Angelicque E., Ribalet, François, and Weitz, Joshua S.

Published
2024
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10. Severe flooding and cause-specific hospitalization in the United States

Author

Aggarwal, Sarika, Hu, Jie K., Sullivan, Jonathan A., Parks, Robbie M., and Nethery, Rachel C.

Subjects
Statistics - Applications
Abstract

Flooding is one of the most disruptive and costliest climate-related disasters and presents an escalating threat to population health due to climate change and urbanization patterns. Previous studies have investigated the consequences of flood exposures on only a handful of health outcomes and focus on a single flood event or affected region. To address this gap, we conducted a nationwide, multi-decade analysis of the impacts of severe floods on a wide range of health outcomes in the United States by linking a novel satellite-based high-resolution flood exposure database with Medicare cause-specific hospitalization records over the period 2000- 2016. Using a self-matched study design with a distributed lag model, we examined how cause-specific hospitalization rates deviate from expected rates during and up to four weeks after severe flood exposure. Our results revealed that risk of hospitalization was consistently elevated during and for at least four weeks following severe flood exposure for nervous system diseases (3.5 %; 95 % confidence interval [CI]: 0.6 %, 6.4 %), skin and subcutaneous tissue diseases (3.4 %; 95 % CI: 0.3 %, 6.7 %), and injury and poisoning (1.5 %; 95 % CI: -0.07 %, 3.2 %). Increases in hospitalization rate for these causes, musculoskeletal system diseases, and mental health-related impacts varied based on proportion of Black residents in each ZIP Code. Our findings demonstrate the need for targeted preparedness strategies for hospital personnel before, during, and after severe flooding.

Published
2023

12. Quantum Non-Demolition Measurement on the Spin Precession of Laser-Trapped $^{171}$Yb Atoms

Author

Yang, Y. A., Zheng, T. A., Wang, S. -Z., Hu, W. -K., Zou, Chang-Ling, Xia, T., and Lu, Z. -T.

Subjects
Physics - Atomic Physics, Quantum Physics
Abstract

Quantum non-demolition (QND) measurement enhances the detection efficiency and measurement fidelity, and is highly desired for its applications in precision measurements and quantum information processing. We propose and demonstrate a QND measurement scheme for the spin states of laser-trapped atoms. On $^{171}$Yb atoms held in an optical dipole trap, a transition that is simultaneously cycling, spin-state selective, and spin-state preserving is created by introducing a circularly polarized beam of control laser to optically dress the spin states in the excited level, while leaving the spin states in the ground level unperturbed. We measure the phase of spin precession of $5\times10^{4}$ atoms in a bias magnetic field of 20 mG. This QND approach reduces the optical absorption detection noise by $\sim$19 dB, to a level of 2.3 dB below the atomic quantum projection noise. In addition to providing a general approach for efficient spin-state readout, this all-optical technique allows quick switching and real-time programming for quantum sensing and quantum information processing.

Published
2022

14. Optically enhanced discharge excitation and trapping of $^{39}Ar$

Author

Chu, Y. -Q., Wan, Z. -F., Ritterbusch, F., Hu, W. -K., Gu, J. -Q., Hu, S. -M., Jia, Z. -H., Jiang, W., Lu, Z. -T., Sun, L. -T., Tong, A. -M., Wang, J. S., and Yang, G. -M.

Subjects
Physics - Atomic Physics
Abstract

We report on a two-fold increase of the $^{39}Ar$ loading rate in an atom trap by enhancing the generation of metastable atoms in a discharge source. Additional atoms in the metastable $1s_5$ level (Paschen notation) are obtained via optically pumping both the $1s_4$ - $2p_6$ transition at 801 nm and the $1s_2$ - $2p_6$ transition at 923 nm. By solving the master equation for the corresponding six-level system, we identify these two transitions to be the most suitable ones and encounter a transfer process between $1s_2$ and $1s_4$ when pumping both transitions simultaneously. We calculate the previously unknown frequency shifts of the two transitions in $^{39}Ar$ and confirm the results with trap loading measurements. The demonstrated increase in the loading rate enables a corresponding decrease in the required sample size, uncertainty and measurement time for $^{39}Ar$ dating, a significant improvement for applications such as dating of ocean water and alpine ice cores., Comment: arXiv admin note: text overlap with arXiv:2005.11056

Published
2022
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15. Cell Layers: uncovering clustering structure in unsupervised single-cell transcriptomic analysis

Author

Blair, Andrew P, Hu, Robert K, Farah, Elie N, Chi, Neil C, Pollard, Katherine S, Przytycki, Pawel F, Kathiriya, Irfan S, and Bruneau, Benoit G

Subjects
Biological Sciences, Genetics, Biotechnology, Generic health relevance
Abstract

MotivationUnsupervised clustering of single-cell transcriptomics is a powerful method for identifying cell populations. Static visualization techniques for single-cell clustering only display results for a single resolution parameter. Analysts will often evaluate more than one resolution parameter but then only report one.ResultsWe developed Cell Layers, an interactive Sankey tool for the quantitative investigation of gene expression, co-expression, biological processes and cluster integrity across clustering resolutions. Cell Layers enhances the interpretability of single-cell clustering by linking molecular data and cluster evaluation metrics, providing novel insight into cell populations.Availability and implementationhttps://github.com/apblair/CellLayers.

Published
2022

19. The effects of computer-aided cognitive rehabilitation combined with virtual reality technology on event-related potential P300 and cognitive function of patients with cognitive impairment after stroke.

Author

SHI, J., MA, S.-J., HU, J., HU, Z.-K., XIA, J.-Y., and XU, H.-Y.

Abstract

OBJECTIVE: The aim of this study was to explore the effects of computer-aided cognitive rehabilitation (CACR) combined with virtual reality (VR) technology on event-related potential P300 and cognitive function in patients with cognitive impairment after stroke. PATIENTS AND METHODS: Clinical data from 94 patients with post-stroke cognitive impairment, admitted to our hospital from January 2020 to March 2023, were retrospectively analyzed. Of them, 45 patients received routine rehabilitation training (Control group), and 49 patients received CACR combined with VR technology (Observation group). Cognitive rehabilitation status, event-related potential P300 examination status, biochemical indices levels, and daily living activity scores of the two groups were evaluated and compared. RESULTS: After treatment, cognitive function significantly improved in the Observation group compared to the Control group. The amplitude of P300 in the Observation group was significantly higher, and the latency was significantly lower compared to the Control group. The levels of brain-derived neurotrophic factor (BDNF) in the Observation group were significantly higher (p<0.05), while the levels of cystatin C (Cys-C) and neuron-specific enolase (NSE) were significantly lower than those in the Control group (p<0.05 each). Patients in the Observation group demonstrated a significantly higher ability to perform daily living activities compared to the Control group (p<0.05). CONCLUSIONS: Compared with conventional rehabilitation training, the combination of CACR and VR technology in the treatment of stroke-induced cognitive impairment is more effective in improving patients' cognitive function, regulating BDNF, Cys-C, and NSE levels, and enhancing patients' ability to perform daily living activities. [ABSTRACT FROM AUTHOR]

Published
2023

20. Study on rolling forming mechanism and influencing factors of blanks with arc-shaped

Author

Zhang, X. Y., Wang, Y., Hu, P. K., Zhang, X. Y., Wang, Y., and Hu, P. K.

Abstract

In this paper, the influence law was analyzed, the effective parameter range was determined. Based on the significance analysis of the orthogonal experiment with three factors and three levels, the order of the influence degree of each parameter on the forming quality of the end is obtained. According to the optimized simulation analysis in the effective scheme, the optimal forming process parameters were determined. The results show that the order of the influence of various factors on the diameter of the roll cut is as follows: roll cutting speed> friction factor> baffle gap; the best combination of process parameters is A2B1C1, the friction factor is 0,5, the roll cutting speed is 1/rad · s-1and the baffle gap is 0,1/mm.

Published
2022

21. Comparing the efficacy of povidone-iodine and normal saline in incisional wound irrigation to prevent superficial surgical site infection: a randomized clinical trial in gastric surgery.

Author

Zhao, L-Y., Zhang, W-H., Liu, K., Chen, X-L., Yang, K., Chen, X-Z., and Hu, J-K.

Abstract

Background: Prevention of surgical site infection (SSI) after gastrectomy has received increasing attention. Prophylactic incisional wound irrigation has been advocated to reduce SSI, but the choice of solution remains under debate.Aims: To compare the efficacies of wound irrigation with normal saline (NS) and povidone-iodine (PVI) for the prevention of SSI after gastrectomy, and to identify the risk factors for SSI.Methods: This randomized, single-centre clinical trial included 340 patients with gastric cancer. They were assigned at random into two groups (ratio 1:1) to receive either 0.9% NS or 1.0% PVI solution for incisional irrigation before wound closure. The primary endpoint was postoperative SSI within 30 days of gastrectomy, and the secondary endpoint was the length of hospital stay.Findings: In total, 333 patients were included in the modified intent-to-treat group, and the SSI rate did not differ significantly between the PVI group (11/167, 6.59%) and the NS group (9/166, 5.42%) [odds ratio (OR) 1.131, 95% confidence interval (CI) 0.459-3.712; P=0.655]. Moreover, the difference between the two groups in terms of length of hospital stay was not significant (P=0.301). Body mass index (BMI) (OR 2.639, 95% CI 1.040-6.694; P=0.041) and postoperative complications (OR 2.565, 95% CI 1.023-6.431; P=0.045) were identified as independent risk factors for SSI.Conclusions: NS and PVI had similar efficacy as prophylactic wound irrigation for the prevention of SSI after gastrectomy. The risk of SSI was higher in patients with high BMI or postoperative complications. [ABSTRACT FROM AUTHOR]

Published
2023
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22. Two‐Step Electron Acceleration During a Flux Rope Crossing of Earth's Bow Shock

Author

Hu, D. K., Liu, Y. Y., Cao, J. B., and Liu, C. M.

Abstract

The generation of cosmic ray particles with ultra‐relativistic energies is a crucial issue in astrophysical and space physics. Shocks have been acknowledged as efficient accelerators in the universe which can produce energetic particles through a variety of mechanisms, such as diffusive shock acceleration (DSA), shock surfing acceleration (SSA) and shock drift acceleration (SDA). Using the data set obtained by the Magnetospheric Multiscale mission, we report an unusually sharp enhancement of energetic electron flux in the upstream region of Earth's bow shock, associated with a bipolar variation of the interplanetary magnetic field. To explain these observations, we propose a two‐step acceleration scenario where electrons trapped in a flux rope (FR) first undergo head‐on collisions and are further accelerated by FR contraction as the FR crosses the shock. Such a scenario can well explain the spacecraft observations. This work can improve our understanding of particle acceleration processes at shocks. The cosmic ray comprises ions and electrons with energies up to 1,020 eV and thus its generation mechanism is an important issue. A conventional theory known as diffusive shock acceleration is a promising candidate but it needs seed electrons with sufficient initial energies. How these electrons are generated is still unclear. In this study, we report an unusually sharp enhancement of energetic electron flux with a large variation of magnetic field direction in the upstream region of Earth's bow shock, and propose a two‐step acceleration scenario to explain the spacecraft measurements. Electrons first gain energies from the head‐on collisions with the bow shock, and then bounce between the two ends of a circular magnetic field of shrinkage, analogous to a ball reflecting between two converging walls. This scenario has been mathematically confirmed and shows good agreement with the spacecraft measurements. Efficient electron acceleration is observed when a flux rope collides with the Earth's bow shockElectrons trapped in the flux rope are successively accelerated by the head‐on reflection at shock front and the flux rope contractionThis two‐step acceleration scenario is mathematically reproduced and fit the spacecraft observations well Efficient electron acceleration is observed when a flux rope collides with the Earth's bow shock Electrons trapped in the flux rope are successively accelerated by the head‐on reflection at shock front and the flux rope contraction This two‐step acceleration scenario is mathematically reproduced and fit the spacecraft observations well

Published
2024
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23. A statistical method for treating the "negative-age" and "negative-atom-number" conundrums in radioisotope dating.

Author

Hu, W.-K., Jiang, W., and Lu, Z.-T.

Subjects
RADIOISOTOPES, ATOM trapping, TRACE analysis
Abstract

In radioisotope dating, statistical fluctuations of atom counts or decay counts can sometimes lead to unphysical results, such as negative counts after subtracting the background or negative apparent ages near the boundaries of the dating range. How to treat these boundary cases with a unified approach and give proper estimates on age limits and confidence intervals is an important issue in radioisotope dating. In this work, we combine the Feldman-Cousins likelihood-ratio ordering method for interval estimation, a Frequentist approach to make consistent transitions from the choice of one-sided limits to two-sided confidence intervals, and a Bayesian method to treat the background uncertainties. This data treatment method naturally eliminates the unphysical results. We use 81Kr dating and Atom Trap Trace Analysis as an example to illustrate the advantages. This method can be generalized to other radioisotopes and ultra-sensitive analysis techniques. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Microbial eukaryotic predation pressure and biomass at deep-sea hydrothermal vents

Author

Hu, Sarah K, Anderson, Rika E, Pachiadaki, Maria G, Edgcomb, Virginia P, Serres, Margrethe H, Sylva, Sean P, German, Christopher R, Seewald, Jeffrey S, Lang, Susan Q, and Huber, Julie A

Abstract

Deep-sea hydrothermal vent geochemistry shapes the foundation of the microbial food web by fueling chemolithoautotrophic microbial activity. Microbial eukaryotes (or protists) play a critical role in hydrothermal vent food webs as consumers and hosts of symbiotic bacteria, and as a nutritional source to higher trophic levels. We measured microbial eukaryotic cell abundance and predation pressure in low-temperature diffuse hydrothermal fluids at the Von Damm and Piccard vent fields along the Mid-Cayman Rise in the Western Caribbean Sea. We present findings from experiments performed under in situpressure that show cell abundances and grazing rates higher than those done at 1 atmosphere (shipboard ambient pressure); this trend was attributed to the impact of depressurization on cell integrity. A relationship between the protistan grazing rate, prey cell abundance, and temperature of end-member hydrothermal vent fluid was observed at both vent fields, regardless of experimental approach. Our results show substantial protistan biomass at hydrothermally fueled microbial food webs, and when coupled with improved grazing estimates, suggest an important contribution of grazers to the local carbon export and supply of nutrient resources to the deep ocean.Graphical Abstract

Published
2024
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25. Nail mesenchyme: Tipping the hand on regeneration

Author

Hu, Jimmy K.

Abstract

Digit tip regeneration rebuilds amputated structures in some mammals if the nail organ is preserved. In recently published Cell Reportspapers, Castilla-Ibeas et al., Johnson et al., and Mahmud et al. define the patterning function and regenerative capacity of the dorsal nail mesenchyme in this process.

Published
2023
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26. cis-Regulatory changes in locomotor genes are associated with the evolution of burrowing behavior

Author

Hu, Caroline K., York, Ryan A., Metz, Hillery C., Bedford, Nicole L., Fraser, Hunter B., and Hoekstra, Hopi E.

Abstract

How evolution modifies complex, innate behaviors is largely unknown. Divergence in many morphological traits, and some behaviors, is linked to cis-regulatory changes in gene expression. Given this, we compare brain gene expression of two interfertile sister species of Peromyscusmice that show large and heritable differences in burrowing behavior. Species-level differential expression and allele-specific expression in F1hybrids indicate a preponderance of cis-regulatory divergence, including many genes whose cis-regulation is affected by burrowing behavior. Genes related to locomotor coordination show the strongest signals of lineage-specific selection on burrowing-induced cis-regulatory changes. Furthermore, genetic markers closest to these candidate genes associate with variation in burrow shape in a genetic cross, suggesting an enrichment for loci affecting burrowing behavior near these candidate locomotor genes. Our results provide insight into how cis-regulated gene expression can depend on behavioral context and how this dynamic regulatory divergence between species may contribute to behavioral evolution.

Published
2022
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