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1. Effects of Fire Intensity and Abiotic Factors on Persistence of an Encroaching Woody Species

   Starns, H. D.; Wonkka, C. L.; Lodge, A. G.; Twidwell, D.; Treadwell, M. L.; Kavanagh, K. L.; Dickinson, M. B.; Tolleson, D. R.; Rogers, W. E. (May 2019, Proceedings of the Albuquerque Fire Behavior and Fuels Conference)

   Over the past century, rangelands worldwide have experienced changes in vegetation cover and structure, many transitioning from grass-dominated to shrub-dominated systems (Archer et al. 2017; Fuhlendorf et al. 2017). In North America, such transitions are primarily a consequence of livestock management and fire exclusion practices of Euro-American settlers (Bray 1904; Archer 1989; Fuhlendorf and Smeins 1997). These shrub-dominated systems are often less productive for wildlife and livestock and may have crossed a threshold which cannot be reversed via common restoration practices such as prescribed fire (Ansley and Castellano 2006; Ratajczak et al. 2016). Oftentimes, the inability of prescribed fire to succeed at crossing this threshold is the result of insufficient fuel loading or inadequate fire intensity due to prescription parameters (Havstad and James 2010; Twidwell et al. 2016). However, recent work has demonstrated that burning under more extreme conditions (e.g. higher temperatures, lower fine fuel moisture) can slow or change the course of encroachment (Twidwell et al. 2013; Twidwell et al. 2016). Many encroaching shrub species are capable of persisting after fire via resprouting from protected buds (Bond and Midgley 2001). Such mechanisms pose challenges for land managers, particularly because resprouting often results in a higher number of stems per individual plant. Mesquite (Prosopis spp.) shrubs are well-known for their ability to persist to varying degrees following disturbance due to fire, chemical, and mechanical treatments. Due to historical livestock management and fire suppression practices, honey mesquite (Prosopis glandulosa) has increased in dominance and abundance in the southern Great Plains since the beginning of Euro-American settlement (Bray 1904; Archer 1989). Although prescribed fire has increased in acceptance as a method to reduce encroachment of mesquite, low-intensity fires performed during the dormant season rarely cause mortality (Wright and Bailey 1980; Ansley et al. 1998), especially when they are performed as a single treatment rather than as part of a comprehensive management plan. However, recent studies have demonstrated that more intense fires conducted outside the dormant season are capable of reducing resprouters (including mesquite), particularly during periods of drought (Twidwell et al. 2016). We evaluated impacts of fire intensity and abiotic factors on persistence of honey mesquite, a species of concern for managers in the southern Great Plains. 

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2. Eliciting imitation in early infancy

   https://doi.org/10.1111/desc.12738  

   Meltzoff, Andrew N.; Murray, Lynne; Simpson, Elizabeth A.; Heimann, Mikael; Nagy, Emese; Nadel, Jacqueline; Pedersen, Eric J.; Brooks, Rechele; Messinger, Daniel S.; De Pascalis, Leonardo; et al (September 2018, Developmental Science)

   We (Meltzoff et al., 2018) described how Oostenbroek et al.’s (2016) design likely dampened infant imitation. In their commentary, Oostenbroek et al. (2018) argue that our points are post hoc. It is important for readers to know that they are not. Our paper restated “best practices” described in published papers. Based on the literature, the design used by Oostenbroek et al. (2016) would be predicted to dampen infant imitation. First, Oostenbroek et al.’s (2016) test periods were too brief. The stimulus presentation for each type of gesture was too short to ensure that neonates saw the display. The response measurement period did not allow neonates sufficient time to organize a motor response. Meltzoff and Moore (1983a, 1994) introduced experimental procedures specifically designed to address these issues (also, Simpson, Murray, Paukner, & Ferrari, 2014). Oostenbroek et al. did not capitalize on these procedural advances. Second, Oostenbroek et al. allowed uncontrolled experimenter–infant interactions during the test session itself. Previous papers on imitation provided analyses of how uncontrolled interactions with the experimenter can introduce “noise” in experiments of facial imitation (Meltzoff & Moore, 1983b, 1994). Third, Oostenbroek et al. used suboptimal eliciting conditions. Neonates cannot support their own heads; in Oostenbroek et al., infants’ heads were allowed to flop from side-to-side unsupported on the experimenter’s lap while the experimenter gestured with both hands. In addition, papers have listed techniques for maximizing visual attention (controlled lighting, homogeneous background) (Meltzoff & Moore, 1989, 1994). Oostenbroek et al. tested infants on a couch in the home. Despite a design that would blunt imitation, our reanalysis of Oostenbroek et al.’s data showed a response pattern that is consistent with the imitation of tongue protrusion (TP). In their commentary, Oostenbroek et al. (2018) now propose limiting analyses to a subset of their original controls. We reanalyzed their data accordingly. Again, the results support early imitation. Their cross-sectional data (Oostenbroek et al., 2016, Table S4) collapsed across age show significantly more infant TP in response to the TP demonstration than to the mean of the six dynamic face controls (mouth, happy, sad, mmm, ee, and click): t(104) = 4.62, p = 0.00001. The results are also significant using a narrower subset of stimuli (mouth, happy, and sad): t(104) = 3.20, p = 0.0018. These results rule out arousal, because the adult TP demonstration was significantly more effective in eliciting infant tongue protrusions than the category of dynamic face controls. Tongue protrusion matching is a robust phenomenon successfully elicited in more than two dozen studies (reviews: Meltzoff & Moore, 1997; Nagy, Pilling, Orvos, & Molnar, 2013; Simpson et al., 2014). There are more general lessons to be drawn. Psychology is experiencing what some call a “replication crisis.” Those who attempt to reproduce effects have scientific responsibilities, as do original authors. Both can help psychology become a more cumulative science. It is crucial for investigators to label whether or not a study is a direct replication attempt. If it is not a direct replication, procedural alterations and associated limitations should be discussed. It sows confusion to use procedures that are already predicted to dampen effects, without alerting readers. Psychology will be advanced by more stringent standards for reporting and evaluating studies aimed at reproducing published effects. Infant imitation is a fundamental skill prior to language and contributes to the development of social cognition. On this both Oostenbroek et al. and we agree. 

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3. Age and tectonic setting of the Paleocene Glacier Island volcanic sequence of the Orca Group in Prince William Sound, Alaska.

   https://doi.org/10.1130/abs/2019CD-329372  

   Noseworthy, C. (April 2019, Proceedings of the Keck Geology Consortium.)

   Southern Alaska has a long history of subduction, accretion, and coastwise transport of terranes (Coney et al., 1980; Monger et al., 1982; Plafker et al., 1994). The Chugach-Prince William (CPW) terrane is about 2200 km long and extends through much of southern Alaska (Plafker et al., 1994) (Fig. 1A). The inboard Chugach terrane can be divided into two parts, a mélange and sedimentary units that are Permian to Early Cretaceous in age and a turbidite sequence that is from the Upper Cretaceous (Plafker et al., 1994). In the Prince William Sound area, the outboard Prince William terrane is comprised of Paleocene to Eocene turbidites and associated basaltic rocks of the Orca Group (Davidson and Garver, 2017), and the turbidites of the inboard Chugach terrane are known as the Valdez Group. The turbidites are intruded by the Sanak-Baranof Belt (SBB), a group of 63-47 Ma plutons that are progressively younger to the east. The Border Ranges fault system marks the northern boundary of the CPW terrane, separating the Chugach terrane from the Wrangellia composite terrane and the Contact fault separates the Chugach and Prince William terrane (Fig. 1; Plafker et al., 1994). There are three ophiolite sequences in the Orca Group: Knight Island (KI), Resurrection Peninsula (RP), and Glacier Island (GI) (Fig. 1B). The KI ophiolite contains a sequence of massive pillow basalts, sheeted dikes, and a minor amount of ultramafic rocks (Tysdal et al, 1977; Nelson and Nelson, 1992; Crowe et al., 1992). The RP ophiolite is a typical ophiolite sequence and has interbedded Paleocene turbidites (Davidson and Garver, 2017). Paleomagnetic data gathered from the RP ophiolite indicated a mean depositional paleolatitude of 54° ± 7° which implies 13° ± 9° of poleward displacement (Bol et al., 1992). These data suggest that the RP ophiolite was translated northward to its current position after being formed in the Pacific Northwest, and thus the CPW terrane may have been originally located at 48-49° north and at 50 Ma was transferred 1100 km to the north by strike-slip faulting (Cowan, 2003). However, an opposing hypothesis suggests that the terrane has not experienced significant displacement and formed in Alaska due to a now-subducted Resurrection plate (Haeussler et al., 2003). KI and RP ophiolites have traditionally been assumed to be oceanic crust that was tectonically emplaced into the CPW terrane (Bol et al., 1992; Lytwyn et al., 1997). However, a more recent study suggests a hypothesis that the ophiolites originated in an upper plate setting and formed due to transtension (Davidson and Garver, 2017). Previous workers have used discriminant diagrams to identify the volcanic rocks of KI ophiolite and RP ophiolite as mid-ocean ridge basalts (Lytwyn et al., 1997; Miner, 2012). This project presents new geochemical and geochronological data from the GI ophiolite to determine its age and tectonic setting. The purpose of this study is to compare the data from GI with the data from KI and RP, and the comparison of the geochemical data will allow for a greater understanding of the tectonic setting of southern Alaska. 

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4. Age and provenance of the Upper Cretaceous to Paleocene Valdez Group of the Chugach Terrane from the Richardson Highway and Northern Prince William Sound, Alaska.

   https://doi.org/10.1130/abs/2019CD-329673  

   Gross Almonte, N. (April 2019, Proceedings of the Keck Geology Consortium)

   The age and provenance of the southern Alaskan Campanian to Paleocene Valdez Group of the Chugach terrane and its relationship with the younger outboard Paleocene to Eocene Orca Group of the Prince William terrane is poorly understood but an important component of the Cordilleran collage (Plafker et al., 1994). The Valdez and Orca Groups are both part of the Chugach-Prince William terrane (CPW), which is a thick accretionary complex that extends 2200 km along the southern Alaskan margin (Fig. 1; Cowan, 2003). The deep-water turbidites of these terranes are quartzofeldspathic and volcanic-lithic sandstones and basaltic rocks (Dumoulin, 1987; Plafker et al., 1994). The CPW is intruded by near-trench plutons of the Sanak-Baranof belt (Davidson and Garver, 2017) and are believed to be related to a slab window that formed during subduction of Kula-Farallon or Kula- Resurrection spreading ridges (Marshak and Karig, 1977; Delong et al., 1978; Moore et al., 1983; Kusky et al., 1997a; Bradley et al., 2003; Haeussler et al., 2003). There are two hypotheses for the formation of the CPW along the North American Cordilleran margin: 1) either the CPW terrane formed in situ by subduction of the Resurrection plate (Haeussler et al. 2003); or 2) the rocks formed in the Pacific Northwest or California and were transported at least 2000 km along coastwise strike-slip fault systems (Cowan, 2003; Garver and Davidson, 2015). This study is an investigation into the age and provenance of the Valdez Group and its relationship with the Orca Group in the central Chugach Mountains using detrital zircon U-Pb dates. New detrital zircon U-Pb dates and their grain-age distributions from the Valdez and Orca Group turbidites are combined with dates from Kochelek et al. (2011), Amato et al. (2013), and Davidson and Garver (2017) and then synthesized to understand the difference in age between the units and provenance. New and existing U-Pb dates indicate maximum depositional ages (MDA) of the Valdez Group are concentrated in three groups: 84-78 Ma, 74-65 Ma, and 62-60 Ma. The youngest group of MDAs are age-correlative with the Orca Group but were collected from rocks in areas mapped as Valdez Group, indicating that either Orca Group rocks occur in the Valdez Group or the youngest Valdez Group rocks are stratigraphically equivalent to those of the oldest Orca Group. If the latter, the Valdez Group is not Campanian to Maastrichtian in age as has been traditionally viewed (Plafker et al., 1994) but is Upper Cretaceous to Paleocene and in part correlative to the lowest part of the Orca Group. 

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5. A Stochastic Analysis of Queues with Customer Choice and Delayed Information

   https://doi.org/10.1287/moor.2019.1024  

   Pender, Jamol; Rand, Richard; Wesson, Elizabeth (August 2020, Mathematics of Operations Research)

   Many service systems provide queue length information to customers, thereby allowing customers to choose among many options of service. However, queue length information is often delayed, and it is often not provided in real time. Recent work by Dong et al. [Dong J, Yom-Tov E, Yom-Tov GB (2018) The impact of delay announcements on hospital network coordination and waiting times. Management Sci. 65(5):1969–1994.] explores the impact of these delays in an empirical study in U.S. hospitals. Work by Pender et al. [Pender J, Rand RH, Wesson E (2017) Queues with choice via delay differential equations. Internat. J. Bifurcation Chaos Appl. Sci. Engrg. 27(4):1730016-1–1730016-20.] uses a two-dimensional fluid model to study the impact of delayed information and determine the exact threshold under which delayed information can cause oscillations in the dynamics of the queue length. In this work, we confirm that the fluid model analyzed by Pender et al. [Pender J, Rand RH, Wesson E (2017) Queues with choice via delay differential equations. Internat. J. Bifurcation Chaos Appl. Sci. Engrg. 27(4):1730016-1–1730016-20.] can be rigorously obtained as a functional law of large numbers limit of a stochastic queueing process, and we generalize their threshold analysis to arbitrary dimensions. Moreover, we prove a functional central limit theorem for the queue length process and show that the scaled queue length converges to a stochastic delay differential equation. Thus, our analysis sheds new insight on how delayed information can produce unexpected system dynamics. 

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