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Galaxies grow by forming stars from cold molecular gas. The rate at which they do so is limited by various feedback processes (such as supernovae or stellar winds) that heat and/or eject gas from the host galaxy. Spilker et al. used submillimeter observations to discover an outflow of molecular gas from a galaxy in the early Universe, a period of vigorous star formation. Modeling the outflow revealed that the mass of gas being ejected is similar to that being turned into stars. The results will help determine how quickly galaxies formed after the Big Bang. Science , this issue p. 1016 A galaxy in the early Universe is driving an outflow of molecular gas, a sign of feedback regulating star formation. Galaxies grow inefficiently, with only a small percentage of the available gas converted into stars each free-fall time. Feedback processes, such as outflowing winds driven by radiation pressure, supernovae, or supermassive black hole accretion, can act to halt star formation if they heat or expel the gas supply. We report a molecular outflow launched from a dust-rich star-forming galaxy at redshift 5.3, 1 billion years after the Big Bang. The outflow reaches velocities up to 800 kilometers per second relative to the galaxy, is resolved into multiple clumps, and carries mass at a rate within a factor of 2 of the star formation rate. Our results show that molecular outflows can remove a large fraction of the gas available for star formation from galaxies at high redshift.

Two extremely massive galaxies are seen 800 million years after the Big Bang, showing the rapid growth of early structure and marking the most massive halo known in that era. A massive galaxy in the early Universe The most massive galaxies in the early Universe were very rare objects and observing them during their growing stage is a challenge. Daniel Marrone and collaborators report observations of one of them less than 800 million years after the Universe began, which high-resolution imaging reveals to in fact be a closely interacting pair of galaxies. The larger one is forming stars at a rate of 2,900 solar masses per year, and contains 270 billion solar masses of gas. The rapid star formation was probably triggered by the interaction with its close companion, whose properties are closer to those of galaxies observed in the nearby Universe. According to the current understanding of cosmic structure formation, the precursors of the most massive structures in the Universe began to form shortly after the Big Bang, in regions corresponding to the largest fluctuations in the cosmic density field 1 , 2 , 3 . Observing these structures during their period of active growth and assembly—the first few hundred million years of the Universe—is challenging because it requires surveys that are sensitive enough to detect the distant galaxies that act as signposts for these structures and wide enough to capture the rarest objects. As a result, very few such objects have been detected so far 4 , 5 . Here we report observations of a far-infrared-luminous object at redshift 6.900 (less than 800 million years after the Big Bang) that was discovered in a wide-field survey 6 . High-resolution imaging shows it to be a pair of extremely massive star-forming galaxies. The larger is forming stars at a rate of 2,900 solar masses per year, contains 270 billion solar masses of gas and 2.5 billion solar masses of dust, and is more massive than any other known object at a redshift of more than 6. Its rapid star formation is probably triggered by its companion galaxy at a projected separation of 8 kiloparsecs. This merging companion hosts 35 billion solar masses of stars and has a star-formation rate of 540 solar masses per year, but has an order of magnitude less gas and dust than its neighbour and physical conditions akin to those observed in lower-metallicity galaxies in the nearby Universe 7 . These objects suggest the presence of a dark-matter halo with a mass of more than 100 billion solar masses, making it among the rarest dark-matter haloes that should exist in the Universe at this epoch.

G12C is a mutation that occurs in approximately 3 to 4% of patients with metastatic colorectal cancer. Monotherapy with KRAS G12C inhibitors has yielded only modest efficacy. Combining the KRAS G12C inhibitor sotorasib with panitumumab, an epidermal growth factor receptor (EGFR) inhibitor, may be an effective strategy. In this phase 3, multicenter, open-label, randomized trial, we assigned patients with chemorefractory metastatic colorectal cancer with mutated G12C who had not received previous treatment with a KRAS G12C inhibitor to receive sotorasib at a dose of 960 mg once daily plus panitumumab (53 patients), sotorasib at a dose of 240 mg once daily plus panitumumab (53 patients), or the investigator's choice of trifluridine-tipiracil or regorafenib (standard care; 54 patients). The primary end point was progression-free survival as assessed by blinded independent central review according to the Response Evaluation Criteria in Solid Tumors, version 1.1. Key secondary end points were overall survival and objective response. After a median follow-up of 7.8 months (range, 0.1 to 13.9), the median progression-free survival was 5.6 months (95% confidence interval [CI], 4.2 to 6.3) and 3.9 months (95% CI, 3.7 to 5.8) in the 960-mg sotorasib-panitumumab and 240-mg sotorasib-panitumumab groups, respectively, as compared with 2.2 months (95% CI, 1.9 to 3.9) in the standard-care group. The hazard ratio for disease progression or death in the 960-mg sotorasib-panitumumab group as compared with the standard-care group was 0.49 (95% CI, 0.30 to 0.80; P = 0.006), and the hazard ratio in the 240-mg sotorasib-panitumumab group was 0.58 (95% CI, 0.36 to 0.93; P = 0.03). Overall survival data are maturing. The objective response was 26.4% (95% CI, 15.3 to 40.3), 5.7% (95% CI, 1.2 to 15.7), and 0% (95% CI, 0.0 to 6.6) in the 960-mg sotorasib-panitumumab, 240-mg sotorasib-panitumumab, and standard-care groups, respectively. Treatment-related adverse events of grade 3 or higher occurred in 35.8%, 30.2%, and 43.1% of patients, respectively. Skin-related toxic effects and hypomagnesemia were the most common adverse events observed with sotorasib-panitumumab. In this phase 3 trial of a KRAS G12C inhibitor plus an EGFR inhibitor in patients with chemorefractory metastatic colorectal cancer, both doses of sotorasib in combination with panitumumab resulted in longer progression-free survival than standard treatment. Toxic effects were as expected for either agent alone and resulted in few discontinuations of treatment. (Funded by Amgen; CodeBreaK 300 ClinicalTrials.gov number, NCT05198934.).

Massive galaxy clusters have been found that date to times as early as three billion years after the Big Bang, containing stars that formed at even earlier epochs1,2,3. The high-redshift progenitors of these galaxy clusters—termed ‘protoclusters’—can be identified in cosmological simulations that have the highest overdensities (greater-than-average densities) of dark matter4,5,6. Protoclusters are expected to contain extremely massive galaxies that can be observed as luminous starbursts7. However, recent detections of possible protoclusters hosting such starbursts8,9,10,11 do not support the kind of rapid cluster-core formation expected from simulations12: the structures observed contain only a handful of starbursting galaxies spread throughout a broad region, with poor evidence for eventual collapse into a protocluster. Here we report observations of carbon monoxide and ionized carbon emission from the source SPT2349-56. We find that this source consists of at least 14 gas-rich galaxies, all lying at redshifts of 4.31. We demonstrate that each of these galaxies is forming stars between 50 and 1,000 times more quickly than our own Milky Way, and that all are located within a projected region that is only around 130 kiloparsecs in diameter. This galaxy surface density is more than ten times the average blank-field value (integrated over all redshifts), and more than 1,000 times the average field volume density. The velocity dispersion (approximately 410 kilometres per second) of these galaxies and the enormous gas and star-formation densities suggest that this system represents the core of a cluster of galaxies that was already at an advanced stage of formation when the Universe was only 1.4 billion years old. A comparison with other known protoclusters at high redshifts shows that SPT2349-56 could be building one of the most massive structures in the Universe today.

Elderly patients are often under-represented in clinical trials of metastatic colorectal cancer. We aimed to assess the efficacy and safety of bevacizumab plus capecitabine compared with capecitabine alone in elderly patients with metastatic colorectal cancer. For this open-label, randomised phase 3 trial, patients aged 70 years and older with previously untreated, unresectable, metastatic colorectal cancer, who were not deemed to be candidates for oxaliplatin-based or irinotecan-based chemotherapy regimens, were randomly assigned in a 1:1 ratio via an interactive voice-response system, stratified by performance status and geographical region. Treatment consisted of capecitabine (1000 mg/m2 orally twice a day on days 1–14) alone or with bevacizumab (7·5 mg/kg intravenously on day 1), given every 3 weeks until disease progression, unacceptable toxic effects, or withdrawal of consent. Efficacy analyses were based on the intention-to-treat population. The primary endpoint was progression-free survival. The trial is registered with ClinicalTrials.gov, number NCT00484939. From July 9, 2007, to Dec 14, 2010, 280 patients with a median age of 76 years (range 70–87) were recruited from 40 sites across ten countries. Patients were randomly assigned to receive either bevacizumab plus capecitabine (n=140) or capecitabine only (n=140). Progression-free survival was significantly longer with bevacizumab and capecitabine than with capecitabine alone (median 9·1 months [95% CI 7·3–11·4] vs 5·1 months [4·2–6·3]; hazard ratio 0·53 [0·41–0·69]; p<0·0001). Treatment-related adverse events of grade 3 or worse occurred in 53 (40%) patients in the combination group and 30 (22%) in the capecitabine group, and treatment-related serious adverse events in 19 (14%) and 11 (8%) patients. The most common grade 3 or worse adverse events of special interest for bevacizumab or chemotherapy were hand-foot syndrome (21 [16%] vs nine [7%]), diarrhoea (nine [7%] vs nine [7%]), and venous thromboembolic events (11 [8%] vs six [4%]). Treatment-related deaths occurred in five patients in the combination group and four in the capecitabine group. The most common any-grade adverse event of special interest for bevacizumab was haemorrhage (34 [25%] vs nine [7%]). The combination of bevacizumab and capecitabine is an effective and well-tolerated regimen for elderly patients with metastatic colorectal cancer. F Hoffmann-La Roche.

Breaking the valley degeneracy in monolayer transition metal dichalcogenides through the valley-selective optical Stark effect (OSE) can be exploited for classical and quantum valleytronic operations such as coherent manipulation of valley superposition states. The strong light-matter interactions responsible for the OSE have historically been described by a two-level dressed-atom model, which assumes noninteracting particles. Here we experimentally show that this model, which works well in semiconductors far from resonance, does not apply for excitation near the exciton resonance in monolayer WS 2 . Instead, we show that an excitonic model of the OSE, which includes many-body Coulomb interactions, is required. We confirm the prediction from this theory that many-body effects between virtual excitons produce a dominant blue-shift for photoexcitation detuned from resonance by less than the exciton binding energy. As such, we suggest that our findings are general to low-dimensional semiconductors that support bound excitons and other many-body Coulomb interactions. Many-body interactions have important consequences for the optoelectronic properties of 2D materials. Here, the authors report on how many-body interactions affect the behavior of the valley-selective optical Stark effect for excitation near the A-exciton resonance in monolayer WS 2 .

The pairing of telecollaboration and focused instruction can lead to measurable gains in second language learners' pragmatic competence. This article examines speech act production in telecollaborative exchange, focusing on the requesting behavior of American learners of German for professional purposes as they interacted with German-speaking professionals in Germany via synchronous Web conferences. Drawing on quantitative and qualitative methods, the study investigated the effect of interaction with expert speakers and the implementation of focused instruction on learners' pragmatic development. Whereas quantitative analysis showed no change between experimental conditions, qualitative analysis of 4 learners' request production over the course of 4 online discussions revealed idiosyncratic developmental pathways and the emergence of a common strategy for managing participation in oral synchronous computer-mediated communication. The findings provide new insight regarding the nature of second language request production and confirm the utility of pragmatics instruction in telecollaboration. At the same time, the study calls for more refined analytical tools when investigating language development in extended telecollaborative discourse. (Verlag).

In a large randomized trial that compares regimens in which brentuximab vedotin replaced bleomycin, the group receiving the brentuximab had a 4.9 percentage-point improvement in modified progression-free survival, less pulmonary toxicity, and more myelotoxicity and neurotoxicity.

Cisplatin and gemcitabine is the standard first-line chemotherapy regimen for patients with advanced biliary tract cancer; expression of VEGF and its receptors is associated with adverse outcomes. We aimed to assess the effect of the addition of cediranib (an oral inhibitor of VEGF receptor 1, 2, and 3) to cisplatin and gemcitabine on progression-free survival. In this multicentre, placebo-controlled, randomised phase 2 study, we recruited patients aged 18 years or older with histologically confirmed or cytologically confirmed advanced biliary tract cancer from hepatobiliary oncology referral centres in the UK. Patients were eligible if they had an ECOG performance status of 0–1 and an estimated life expectancy of longer than 3 months. Patients were given first-line cisplatin and gemcitabine chemotherapy (25 mg/m2 cisplatin and 1000 mg/m2 gemcitabine [on days 1 and 8 every 21 days, for up to eight cycles]) with either 20 mg oral cediranib or placebo once a day until disease progression. We randomly assigned patients (1:1) with a minimisation algorithm, incorporating the stratification factors: extent of disease, primary disease site, previous treatment, ECOG performance status, and centre. The primary endpoint was progression-free survival in the intention-to-treat population. This study is registered with ClinicalTrials.gov, number NCT00939848, and was closed on Sept 30, 2014; results of the final analysis for the primary endpoint are presented. Between April 5, 2011, and Sept 28, 2012, we enrolled 124 patients (62 in each group). With a median follow-up of 12·2 months (IQR 7·3–18·5), median progression-free survival was 8·0 months (95% CI 6·5–9·3) in the cediranib group and 7·4 months (5·7–8·5) in the placebo group (HR 0·93, 80% CI 0·74–1·19, 95% CI 0·65–1·35; p=0·72). Patients who received cediranib had more grade 3–4 toxic effects than did patients who received placebo: hypertension (23 [37%] vs 13 [21%]; p=0·05), diarrhoea (eight [13%] vs two [3%]; p=0·05); platelet count decreased (ten [16%] vs four [6%]; p=0·09), white blood cell decreased (15 [24%] vs seven [11%]; p=0·06) and fatigue (16 [24%] vs seven [11%]; p=0·04). Cediranib did not improve the progression-free survival of patients with advanced biliary tract cancer in combination with cisplatin and gemcitabine, which remains the standard of care. Although patients in the cediranib group had more adverse events, we recorded no unexpected toxic effects. The role of VEGF inhibition in addition to chemotherapy for patients with advanced biliary tract cancer remains investigational. Cancer Research UK and AstraZeneca Pharmaceuticals.