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We present the detection of directional muon beams produced using a PW laser at the Lawrence Berkeley National Laboratory. The muon source is a multi-GeV electron beam generated in a 30 cm laser plasma accelerator interacting with a high-Z converter target. The GeV photons resulting from the interaction are converted into a high-flux, directional muon beam via pair production. By employing scintillators to capture delayed events, we were able to identify the produced muons and characterize the source. Using theoretical knowledge of the muon production process combined with simulations that show outstanding agreement with the experiments, we demonstrate that the multi-GeV electron beams produce muon beams with GeV energies and fluxes, at a few meters from the source, up to 4 orders of magnitude higher than cosmic ray muons. Laser-plasma-accelerator-based muon sources can therefore enhance muon imaging applications thanks to their compactness, directionality, and high fluxes which reduce the exposure time by orders of magnitude compared to cosmic ray muons. Using the Geant4-based simulation code we developed to gain insight into the experimental results, we can design future experiments and applications based on LPA-generated muons.

We characterize blue straggler stars (BSS) and yellow straggler stars (YSS) of an open cluster (OC) Berkeley 39 using multi-wavelength observations including Swift/UVOT. Our analysis also makes use of ultraviolet (UV) data from GALEX, optical data from Gaia DR3 and Pan-STARRS, and infrared data from 2MASS, Spitzer/IRAC, and WISE. Berkeley 39 is a ~6 Gyr old Galactic OC located at a distance of ~4200 pc. We identify 729 sources as cluster members utilizing a machine learning algorithm, ML-MOC, on Gaia DR3 data. Of these, 17 sources are classified as BSS candidates and four as YSS candidates. We construct multi-wavelength spectral energy distributions (SEDs) of 16 BSS and 2 YSS candidates, within the Swift/UVOT field, to analyze their properties. Out of these, 8 BSS candidates and both the YSS candidates are successfully fitted with single-component SEDs. Five BSS candidates show marginal excess in the near-UV (fractional residual < 0.3 in all but one UVOT filter), whereas three BSS candidates show moderate to significant excess in the near-UV (fractional residual > 0.3 in at least two UVOT filters). We present the properties of the BSS and YSS candidates, estimated based on the SED fits.

We introduce Berkeley Humanoid, a reliable and low-cost mid-scale humanoid research platform for learning-based control. Our lightweight, in-house-built robot is designed specifically for learning algorithms with low simulation complexity, anthropomorphic motion, and high reliability against falls. The robot's narrow sim-to-real gap enables agile and robust locomotion across various terrains in outdoor environments, achieved with a simple reinforcement learning controller using light domain randomization. Furthermore, we demonstrate the robot traversing for hundreds of meters, walking on a steep unpaved trail, and hopping with single and double legs as a testimony to its high performance in dynamical walking. Capable of omnidirectional locomotion and withstanding large perturbations with a compact setup, our system aims for scalable, sim-to-real deployment of learning-based humanoid systems. Please check http://berkeley-humanoid.com for more details., Comment: 12 pages, 9 figures

The classical Cepheids CE Cas A, CE Cas B, CF Cas, and CG Cas are likely members of the binary open cluster comprising NGC 7790 and Berkeley 58. The clusters are of comparable age and in close proximity, as deduced from differentially dereddened $UuB_PBVGR_P$ photometry, and Cepheid period-age relations. Gaia DR3 astrometric and spectroscopic solutions for the clusters are likewise consistent. Conversely, the seemingly adjacent open cluster NGC 7788 is substantially younger and less distant., Comment: To be accepted for publication

We present a multi-wavelength analysis of the young star cluster Berkeley 59 (Be 59) based on the $Gaia$ data and deep infrared (IR) observations with the 3.58-m Telescopio Nazionale Galileo and $Spitzer$ space telescope. The mean proper motion of the cluster is found to be $\mu$$_\alpha$cos$\delta$ $\sim$ -0.63 mas yr$^{-1}$ and $\mu$$_\delta$ $\sim$ -1.83 mas yr$^{-1}$ and the kinematic distance of the cluster, $\sim$ 1 kpc, is in agreement with previous photometric studies. Present data is the deepest available near-IR observations for the cluster so far and reached below 0.03 M$_\odot$. The mass function of the cluster region is calculated using the statistically cleaned color-magnitude diagram and is similar to the Salpeter value for the member stars above 0.4 M$_\odot$. In contrast, the slope becomes shallower ($\Gamma$ $\sim$ 0.01 $\pm$ 0.18) in the mass range 0.04 - 0.4 M$_\odot$, comparable to other nearby clusters. The spatial distribution of young brown dwarfs (BDs) and stellar candidates shows a non-homogeneous distribution. This suggests that the radiation feedback from massive stars may be a prominent factor contributing to the BD population in the cluster Be 59. We also estimated the star-to-BD ratio for the cluster, which is found to be $\sim$ 3.6. The Kolomogorov-Smirnov test shows that stellar and BD populations significantly differ, and stellar candidates are near the cluster center compared to the BDs, suggesting mass segregation in the cluster toward the substellar mass regime., Comment: 18 pages, 11 Figures, accepted for the publication in the AJ

We introduce "$n$-choiceless" supercompact and extendible cardinals in Zermelo-Fraenkel set theory without the Axiom of Choice. We prove relations between these cardinals and Vop\v{e}nka's Principle similar to those of Bagaria's work in his papers "$C^{(n)}$-Cardinals" and "More on the Preservation of Large Cardinals Under Class Forcing." We use these relations to characterize Berkeley cardinals in terms of a restricted form of Vop\v{e}nka's Principle. Finally, we establish the equiconsistency of the "$n$-choiceless" extendible cardinals with their original counterparts, and study the consistency strength of other relevant theories., Comment: 24 pages

We observed the Galactic open cluster Berkeley 50 in order to determine its stellar content, distance, and age. We obtained UBV photometry of 1145 stars in a 12.3' $\times$ 12.3' field, and used Gaia proper motions and parallaxes to identify 64 members, of which we obtained spectra of the 17 brightest members. The majority of the observed population we classified as B dwarfs, with the exception of a newly identified red supergiant star, which our spectroscopy shows has a B-type companion. Our study establishes the distance as 3.8 kpc, with an average color-excess $E(B-V)=0.9$. Comparison of the physical properties of the cluster with the Geneva evolutionary tracks places the age of the cluster as 50-60 Myr, with its most massive members being $\sim7M_\odot$., Comment: Astronomical Journal, in press. This revision contains additional acknowledgements

Following \cite{bagaria2019large}, given cardinals $\kappa<\lambda$, we say $\kappa$ is a club $\lambda$-Berkeley cardinal if for every transitive set $N$ of size $<\lambda$ such that $\kappa\subseteq N$, there is a club $C\subseteq \kappa$ with the property that for every $\eta\in C$ there is an elementary embedding $j: N\rightarrow N$ with crit$(j)=\eta$. We say $\kappa$ is $\nu$-club $\lambda$-Berkeley if $C\subseteq \kappa$ as above is a $\nu$-club. We say $\kappa$ is $\lambda$-Berkeley if $C$ is unbounded in $\kappa$. We show that under AD$^+$, (1) every regular Suslin cardinal is $\omega$-club $\Theta$-Berkeley (see \rthm{main theorem}), (2) $\omega_1$ is club $\Theta$-Berkeley (see \rthm{main theorem lr} and \rthm{main theorem}), and (3) the ${\tilde\delta}^1_{2n}$'s are $\Theta$-Berkeley -- in particular, $\omega_2$ is $\Theta$-Berkeley (see \rrem{omega2}). Along the way, we represent regular Suslin cardinals in direct limits as cutpoint cardinals (see \rthm{char extenders}). This topic has been studied in \cite{MPSC} and \cite{jackson2022suslin}, albeit from a different point of view. We also show that, assuming $V=L(\mathbb{R})+{\mathrm{AD}}$, $\omega_1$ is not $\Theta^+$-Berkeley, so the result stated in the title is optimal (see \rthm{lr optimal} and \rthm{thetareg optimal}).

Computational microscopy, in which hardware and algorithms of an imaging system are jointly designed, shows promise for making imaging systems that cost less, perform more robustly, and collect new types of information. Often, the performance of computational imaging systems, especially those that incorporate machine learning, is sample-dependent. Thus, standardized datasets are an essential tool for comparing the performance of different approaches. Here, we introduce the Berkeley Single Cell Computational Microscopy (BSCCM) dataset, which contains over ~12,000,000 images of 400,000 of individual white blood cells. The dataset contains images captured with multiple illumination patterns on an LED array microscope and fluorescent measurements of the abundance of surface proteins that mark different cell types. We hope this dataset will provide a valuable resource for the development and testing of new algorithms in computational microscopy and computer vision with practical biomedical applications.

The following essay details a debate between UC Berkeley and a Regent who made charges of discrimination against Asian American students that are similar to the current legal challenges facing Harvard University. The crux of such charges: on average, that one racial or ethnic group is more "qualified" than other groups, often underrepresented minorities, yet they have lower admissions rates. In 2004, Regent John Moores, convinced of discriminatory practices toward Asian-American students in the admissions process at Berkeley, did his own analysis of UC admissions data focused on SAT scores and that he publicized in the "LA Times" and other venues. Moores claimed his investigation provided clear evidence of discrimination. In the aftermath of California's Proposition 209 barring the use of race in admissions, Moores complained that Berkeley's adoption of a "holistic" review of applications reduced the importance of test scores by elevating subjective "measurements" that served as possibly illegal proxies for race and ethnicity. Conjuring memories of charges of discrimination in the 1980s by the Asian-American community regarding Berkeley's admissions processes, Moores asked, "How did the university get away with discriminating so blatantly against Asians?" For anti-affirmative action advocates, like Moores, standardized test scores were, and are, seen as the gold standard of academic ability since it is a "universal" measure unlike grades that are local assessments of abilities and subject to grade inflation. However, when compared to grades in high school, test scores have proven weak indicators of subsequent academic success at highly selective universities that must choose among a large pool of highly qualified students. Test scores also are not necessarily good measures for predicting the future engagement of students in the wide range of experiences and opportunities offered by major universities -- including public service, undergraduate research, and co-curricular activities. Anti-affirmative action advocates largely see admissions as a reward based on test scores and are not terribly concerned with the predictive validity of other admissions criteria. This essay concludes with a brief discussion of the similarities of Moores' analysis and charge of discrimination in admissions with that at Harvard, and the probable legal path toward a new Supreme Court decision on affirmative action.

The current plan divides the UC Berkeley (UCB) campus energy system into five nodes, where the Business and Law node was studied because of an open field site for borehole installation. The Pacific Northwest National Laboratory's Commercial Prototype Building Models were used to estimate heating and cooling load requirements for UCB campus building types by considering model characteristics (for example, high base load from hospitals, high DHW in hotels) corresponding to the ASHRAE Standard 90.1-2013. Unscaled load profiles were created from the EnergyPlus building energy simulation and scaled with monitored peak load and annual energy use to generate the target node's hourly heating and cooling load profiles. An optimization problem was solved to design a hybrid GSHP system, where the objective function is the lifetime total cost of the system, and the optimization variables are the portion of heating and cooling loads covered by the GSHP system. Modelica models for air source and ground source heat pump systems were built for detailed case studies based on optimization results. In the Modelica model, the demand side is connected to the radiators in the building to transfer heat, and the source side is connected to GSHP, ASHP, or other heating and cooling facilities. The results demonstrate that an appropriate hybrid GSHP system can help reduce both borehole numbers and electricity consumption for the UCB campus site.