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Abstract The impact of latitudinal variations in the Intertropical Convergence Zone (ITCZ) on northern Andean hydroclimate during the Medieval Climate Anomaly (MCA; 950–1,150 CE) and Little Ice Age (LIA; 1,300–1,850 CE) is uncertain. Synthesis of two new lacustrine paleoclimate records from the Eastern Colombian Andes with existing circum‐Andean records shows that effective moisture anomalies were synchronous and in phase across the tropical Andes during the last millennium. During the MCA, when the ITCZ was shifted northward, topographically controlled responses in the northern Andes to vigorous atmospheric convection resulted in low precipitation and high evaporation, while precipitation was also reduced in the southern tropical Andes. During the LIA, precipitation decreased in the northern Andes as the ITCZ migrated southward but was offset by cooling that lowered evaporation, establishing high effective moisture. In the southern tropical Andes, the southward ITCZ position simultaneously strengthened precipitation, increasing effective moisture. MCA‐like responses to continued warming trends could similarly reduce northern Andean precipitation while increasing evaporation, thereby lowering effective moisture and possibly reducing water resource availability. 

Teacher turnover in science and mathematics is a significant and consistent challenge for K-12 education in the U.S. This paper provides: (a) an investigation of the relationship between teacher retention and several social and motivational factors; and (b) a comparison of Master Teaching Fellows (MTF) and non-MTF teachers in terms of their retention and social and motivational factors. Teachers are classified into three retention categories: (a) stayers, (b) shifters, and (c) leavers. Social and motivational factors included teaching self-efficacy, diversity dispositions, leadership skills, principal autonomy support, teacher-school fit (adapted from person-organization fit literature), and social networks related to teaching and education. Study 1 included about 250 science and math teachers from the gulf coast region of Texas. Study 2 included 167 science and math teachers across the country. Teachers completed a survey in the summer and fall of 2021. For study 1, multinomial logistics regression analyses indicate: (a) leavers have significantly higher levels of self-efficacy; and (b) shifters have significantly higher levels of leadership skills and lower levels of teacher-school fit. The second study findings indicate: (a) MTFs’ teacher leadership network and teaching self-efficacy are significantly greater than that of non-MTFs’; and (b) MTFs significantly tend to shift to a leadership position than non-MTFs do. 

Teacher turnover i science and mathematics is a significant and consistent challenge for K-12 education in the U.S. This paper provides: (a) an investigation of the relationship between teacher retention and several social and motivational factors; and (b) a comparison of Master Teaching Fellows (MTF) and non-MTF teachers in terms of their retention and social and motivational factors. Teachers are classified into three retention categories: (a) stayers, (b) shifters, and (c) leavers. Social and motivational factors included teaching self-efficacy, diversity dispositions, leadership skills, principal autonomy support, teachers-school fit (adapted from person-organization fit literature), and social networks related to teaching and education. Study 1 included about 250 science and math teachers from the gulf coast region of Texas. Study 2 included 167 science and math teachers across the country. Teachers completed a survey in the summer and fall of 2021. For study 1, multinomial logistics regression analyses indicate: (a) leavers have significantly higher levels of self-efficacy; and (b) shifters have significantly higher levels of leadership skills and lower levels of teacher-school fit. The second study findings indicate: (a) MTFs' teacher leadership network and teaching self-efficacy are significantly greater than that of non-MTFs'; and (b) MTFs significantly tend to shift to a leadership position than non-MTFs do. 

Abstract The Gravitational-Wave Transient Catalog (GWTC) is a collection of short-duration (transient) gravitational-wave signals identified by the LIGO–Virgo–KAGRA Collaboration in gravitational-wave data produced by the eponymous detectors. The catalog provides information about the identified candidates, such as the arrival time and amplitude of the signal and properties of the signal’s source as inferred from the observational data. GWTC is the data release of this dataset, and version 4.0 extends the catalog to include observations made during the first part of the fourth LIGO–Virgo–KAGRA observing run up until 2024 January 31. This Letter marks an introduction to a collection of articles related to this version of the catalog, GWTC-4.0. The collection of articles accompanying the catalog provides documentation of the methods used to analyze the data, summaries of the catalog of events, observational measurements drawn from the population, and detailed discussions of selected candidates.