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This paper explores the relationship between high school students’ shifting computer science (CS) identity and engagement over the course of one school year in both Advanced Placement Computer Science Principles and Exploring Computer Science classrooms in a large US west coast urban school district. Through an analysis of over 500 pre- and post-surveys administered during the 2018-19 school year—with an intersectional analysis comparing Latina and Latino perspectives in this primarily low-income, Latino/a/x school district—this paper answers the following research questions: (1) Who identifies as “CS people” and what does that mean to them? and (2) Which teaching practices seem to have the greatest relationship with CS identification and engagement? 

Taking a justice-oriented approach to equity in Computer Science (CS) education, this paper questions the dominant discourse in CS education and asks what truly makes CS learning consequential from the perspective of youth. We define CS learning as consequential by focusing on its transformative impact on youth identity, agency, and perceptions of the world within and beyond CS classrooms, regardless of whether or not they pursue CS in the future. Our research-practice partnership used qualitative data, specifically longitudinal interview data with 30 students up to three years after they first experienced a high school CS class in a large public school district on the west coast serving majority Latinx, urban, low-income students. Our findings suggest that in order for CS learning to be meaningful and consequential for youth, learning must involve: 1) freedom for youth to express their interests, passions, and concerns; 2) opportunities for youth to expand their views of CS and self; and 3) teacher care for students, learning community, and subject matter. The findings have significant implications for the broader “CS for All” movement and future efforts to reform policy agendas aiming for a more justice-centered CS education. 

An electrically conductive metal typically transmits or absorbs a spin current. Here, we report on evidence that interfacing two metal thin films can suppress spin transmission and absorption. We examine spin pumping in spin-source/spacer/spin-sink heterostructures, where the spacer consists of metallic Cu and Cr thin films. The Cu/Cr spacer largely suppresses spin pumping—i.e., neither transmitting nor absorbing a significant amount of spin current—even though Cu or Cr alone transmits a sizable spin current. The antiferromagnetism of Cr is not essential for the suppression of spin pumping, as we observe similar suppression with Cu/V spacers with V as a nonmagnetic analog of Cr. We speculate that diverse combinations of spin-transparent metals may form interfaces that suppress spin pumping, although the underlying mechanism remains unclear. Our work may stimulate a new perspective on spin transport in metallic multilayers.

 

The Computer Science for All movement is bringing CS to K-12 classrooms across the nation. At the same time, new technologies created by computer scientists have been reproducing existing inequities that directly impact today's youth, while being “promoted and perceived as more objective or progressive than the discriminatory systems of a previous era” [1, p. 5–6]. Current efforts are being made to expose students to the social impact and ethics of computing at both the K-12 and university-level—which we refer to as “socially responsible computing” (SRC) in this paper. Yet there is a lack of research describing what such SRC teaching and learning actively involve and look like, particularly in K-12 classrooms. This paper fills this gap with findings from a research-practice partnership, through a qualitative study in an Advanced Placement Computer Science Principles classroom enrolling low-income Latino/a/x students from a large urban community. The findings illustrate 1) details of teaching practice and student learning during discussions about SRC; 2) the impact these SRC experiences have on student engagement with CS; 3) a teacher's reflections on key considerations for effective SRC pedagogy; and 4) why students’ perspectives and agency must be centered through SRC in computing education. 

We conduct a systematic tidal disruption event (TDE) demographics analysis using the largest sample of optically selected TDEs. A flux-limited, spectroscopically complete sample of 33 TDEs is constructed using the Zwicky Transient Facility over 3 yr (from 2018 October to 2021 September). We infer the black hole (BH) mass (M_BH) with host galaxy scaling relations, showing that the sampleM_BHranges from 10^5.1M_⊙to 10^8.2M_⊙. We developed a survey efficiency corrected maximum volume method to infer the rates. The rest-frameg-band luminosity function can be well described by a broken power law of$\varphi (L_g)\propto {\left[{\left(L_g/L_{\mathrm{bk}}\right)}^{0.3}+{\left(L_g/L_{\mathrm{bk}}\right)}^{2.6}\right]}^{-1}$, withL_bk= 10^43.1erg s⁻¹. In the BH mass regime of 10^5.3≲ (M_BH/M_⊙) ≲ 10^7.3, the TDE mass function follows$\varphi (M_{\mathrm{BH}})\propto M_{\mathrm{BH}}^{-0.25}$, which favors a flat local BH mass function (${\mathit{dn}}_{\mathrm{BH}}/d\log M_{\mathrm{BH}}\approx \mathrm{constant}$). We confirm the significant rate suppression at the high-mass end (M_BH≳ 10^7.5M_⊙), which is consistent with theoretical predictions considering direct capture of hydrogen-burning stars by the event horizon. At a host galaxy mass ofM_gal∼ 10¹⁰M_⊙, the average optical TDE rate is ≈3.2 × 10⁻⁵galaxy⁻¹yr⁻¹. We constrain the optical TDE rate to be [3.7, 7.4, and 1.6] × 10⁻⁵galaxy⁻¹yr⁻¹in galaxies with red, green, and blue colors.

 

The mutant form of the guanosine triphosphatase (GTPase) KRAS is a key driver in human tumors but remains a challenging therapeutic target, making KRAS MUT cancers a highly unmet clinical need. Here, we report a class of bottlebrush polyethylene glycol (PEG)–conjugated antisense oligonucleotides (ASOs) for potent in vivo KRAS depletion. Owing to their highly branched architecture, these molecular nanoconstructs suppress nearly all side effects associated with DNA–protein interactions and substantially enhance the pharmacological properties of the ASO, such as plasma pharmacokinetics and tumor uptake. Systemic delivery to mice bearing human non–small-cell lung carcinoma xenografts results in a significant reduction in both KRAS levels and tumor growth, and the antitumor performance well exceeds that of current popular ASO paradigms, such as chemically modified oligonucleotides and PEGylation using linear or slightly branched PEG. Importantly, these conjugates relax the requirement on the ASO chemistry, allowing unmodified, natural phosphodiester ASOs to achieve efficacy comparable to that of chemically modified ones. Both the bottlebrush polymer and its ASO conjugates appear to be safe and well tolerated in mice. Together, these data indicate that the molecular brush–ASO conjugate is a promising therapeutic platform for the treatment of KRAS -driven human cancers and warrant further preclinical and clinical development. 

Abstract Tidal disruption events (TDEs) offer a unique way to study dormant black holes. While the number of observed TDEs has grown thanks to the emergence of wide-field surveys in the past few decades, questions regarding the nature of the observed optical, UV, and X-ray emission remain. We present a uniformly selected sample of 30 spectroscopically classified TDEs from the Zwicky Transient Facility Phase I survey operations with follow-up Swift UV and X-ray observations. Through our investigation into correlations between light-curve properties, we recover a shallow positive correlation between the peak bolometric luminosity and decay timescales. We introduce a new spectroscopic class of TDE, TDE-featureless, which are characterized by featureless optical spectra. The new TDE-featureless class shows larger peak bolometric luminosities, peak blackbody temperatures, and peak blackbody radii. We examine the differences between the X-ray bright and X-ray faint populations of TDEs in this sample, finding that X-ray bright TDEs show higher peak blackbody luminosities than the X-ray faint subsample. This sample of optically selected TDEs is the largest sample of TDEs from a single survey yet, and the systematic discovery, classification, and follow-up of this sample allows for robust characterization of TDE properties, an important stepping stone looking forward toward the Rubin era. 

Background and Context: Most large-scale statewide initiatives of the Computer Science for All (CS for All) movement have focused on the classroom level. Critical questions remain about building school and district leadership capacity to support teachers while implementing equitable computer science education that is scalable and sustainable.

Objective: This statewide research-practice partnership, involving university researchers and school leaders from 14 local education agencies (LEA) from district and county offices, addresses the following research question: What do administrators identify as most helpful for understanding issues related to equitable computer science implementation when engaging with a guide and workshop we collaboratively developed to help leadership in such efforts?

Method: Participant surveys, interviews, and workshop observations were analyzed to understand best practices for professional development supporting educational leaders.

Findings: Administrators value computer science professional development resources that: (a) have a clear focus on “equity;” (b) engage with data and examples that deepen understandings of equity; (c) provide networking opportunities; (d) have explicit workshop purpose and activities; and (e) support deeper discussions of computer science implementation challenges through pairing a workshop and a guide.

Implications: Utilizing Ishimaru and Galloway’s (2014) framework for equitable leadership practices, this study offers an actionable construct for equitable implementation of computer science including (a) how to build equity leadership and vision; (b) how to enact that vision; and (c) how to scale and sustain that vision. While this construct applies to equitable leadership practices more broadly across all disciplines, we found its application particularly useful when explicitly focused on equity leadership practices in computer science.