Westward Expansion by Juniperus virginiana of the Eastern United States and Intersection with Western Juniperus Species in a Novel Assemblage

Eastern redcedar (Juniperus virginiana L.) is increasing in density in the eastern United States and expanding in range to the west, while western Juniperus species also are increasing and expanding, creating the potential for a novel assemblage. I estimated range expansion and intersection by comparing recent USDA Forest Service Forest Inventory and Analysis surveys (mean year = 2009) to the oldest available surveys (mean year = 1981), with adjustments for sampling changes, and predicted climate envelopes during the following year ranges: 1500–1599, 1800–1849, 1850–1899, 1900–1949, and 1960–1989. During approximately 28 years, eastern redcedar range expanded by about 54 million ha (based on ≥0.5% of total stems ≥12.7 cm in diameter in ecological subsections). Combined range of western species of juniper did not expand. Range intersection of eastern redcedar and western Juniperus species totaled 200,000 km2 and increased by 31,600 km2 over time, representing a novel assemblage of eastern and western species. Predicted ranges during the other time intervals were 94% to 98% of predicted area during 1960–1989, suggesting major climate conditions have been suitable for centuries. The southern western Juniperus species and Rocky Mountain juniper (Juniperus scopulorum Sarg.) have the greatest potential for intersection with eastern redcedar, whereas eastern redcedar may have concluded westward expansion.

Isotopic Evidence for Sources of Dissolved Carbon and the Role of Organic Matter Respiration in the Fraser River Basin, Canada

Sources of dissolved and particulate carbon to the Fraser River system vary significantly in space and time. Tributaries in the northern interior of the basin consistently deliver higher concentrations of dissolved organic carbon (DOC) to the main stem than other tributaries. Based on samples collected near the Fraser River mouth throughout 2013, the radiocarbon age of DOC exported from the Fraser River does not change significantly across seasons despite a spike in DOC concentration during the freshet, suggesting modulation of heterogeneous upstream signals during transit through the river basin. Dissolved inorganic carbon (DIC) concentrations are highest in the Rocky Mountain headwater region where carbonate weathering is evident, but also in tributaries with high DOC concentrations, suggesting that DOC respiration may be responsible for a significant portion of DIC in this basin. Using an isotope and major ion mass balance approach to constrain the contributions of carbonate and silicate weathering and DOC respiration, we estimate that up to 29% of DIC is derived from DOC respiration in some parts of the Fraser River basin. Overall, these results indicate close coupling between the cycling of DOC and DIC, and that carbon is actively processed and transformed during transport through the river network.

Crossing Treeline: Bacterioplankton Communities of Alpine and Subalpine Rocky Mountain Lakes

From the aboveground vegetation to the belowground microbes, terrestrial communities differ between the highly divergent alpine (above treeline) and subalpine (below treeline) ecosystems. Yet, much less is known about the partitioning of microbial communities between alpine and subalpine lakes. Our goal was to determine whether the composition of bacterioplankton communities of high-elevation mountain lakes differed across treeline, identify key players in driving the community composition, and identify potential environmental factors that may be driving differences. To do so, we compared bacterial community composition (using 16S rDNA sequencing) of alpine and subalpine lakes in the Southern Rocky Mountain ecoregion at two time points: once in the early summer and once in the late summer. In the early summer (July), shortly after peak runoff, bacterial communities of alpine lakes were distinct from subalpine lakes. Interestingly, by the end of the summer (approximately 5 weeks after the first visit in August), bacterial communities of alpine and subalpine lakes were no longer distinct. Several bacterial amplicon sequence variants (ASVs) were also identified as key players by significantly contributing to the community dissimilarity. The community divergence across treeline found in the early summer was correlated with several environmental factors, including dissolved organic carbon (DOC), pH, chlorophyll-a (chl-a), and total dissolved nitrogen (TDN). In this paper, we offer several potential scenarios driven by both biotic and abiotic factors that could lead to the observed patterns. While the mechanisms for these patterns are yet to be determined, the community dissimilarity in the early summer correlates with the timing of increased hydrologic connections with the terrestrial environment. Springtime snowmelt brings the flushing of mountain watersheds that connects terrestrial and aquatic ecosystems. This connectivity declines precipitously throughout the summer after snowmelt is complete. Regional climate change is predicted to bring alterations to precipitation and snowpack, which can modify the flushing of solutes, nutrients, and terrestrial microbes into lakes. Future preservation of the unique alpine lake ecosystem is dependent on a better understanding of ecosystem partitioning across treeline and careful consideration of terrestrial-aquatic connections in mountain watersheds.

Learning to Improve Program Systems While Navigating Program and Institutional Constraints

Many youth worker professional development (PD) efforts tend to focus on individualized skill development, rather than learning as a contextualized phenomenon that impacts youth workers’ everyday experiences in the field. Youth worker learning is fundamentally embedded in a broader ecosystem of programs, institutions, and systems that influence how they make sense of and implement their learnings. Examining institutionalized experiences and how they shape youth workers’ response to PD requires attention to the larger ecology of the contexts in which they work. In this paper, I analyze a PD initiative facilitated by a school district in the Rocky Mountain West. Data collected during the PD show that participating youth workers made changes to their program systems. At the same time, participants reported a range of institutional constraints that did not cohere with the PD. I bridge sensemaking theory to research on youth worker self-efficacy to unpack youth workers’ reaction to and implementation of the PD, and I discuss implications for youth worker PD. I propose that PD efforts could more closely attend to youth workers’ institutional contexts.

A storyline view of the projected role of remote drivers on summer air stagnation in Europe and the United States

Storylines of atmospheric circulation change, or physically self-consistent narratives of plausible future events, have recently been proposed as a non-probabilistic means to represent uncertainties in climate change projections. Here, we apply the storyline approach to 21st century projections of summer air stagnation over Europe and the United States. We use a CMIP6 ensemble to generate stagnation storylines based on the forced response of three remote drivers of the Northern Hemisphere mid-latitude atmospheric circulation: North Atlantic warming, North Pacific warming, and tropical versus Arctic warming. Under a high radiative forcing scenario (SSP5-8.5), models consistently project increases in stagnation over Europe and the U.S., but the magnitude and spatial distribution of changes vary substantially across CMIP6 ensemble members, suggesting that future projections are not well-constrained when using the ensemble mean alone. We find that the diversity of projected stagnation changes depends on the forced response of remote drivers in individual models. This is especially true in Europe, where differences of ~2 summer stagnant days per degree of global warming are found amongst the different storyline combinations. For example, the greatest projected increase in stagnation for most European regions leads to the smallest increase in stagnation for southwestern Europe; i.e., limited North Atlantic warming combined with near-equitable tropical and Arctic warming. In the U.S., only the atmosphere over the northern Rocky Mountain states demonstrates comparable stagnation projection uncertainty, due to opposite influences of remote drivers on the meteorological conditions that lead to stagnation.

The Retropepsin-Type Protease APRc as a Novel Ig-Binding Protein and Moonlighting Immune Evasion Factor of Rickettsia

Many Rickettsia organisms are pathogenic to humans, causing severe infections, like Rocky Mountain spotted fever and Mediterranean spotted fever. However, immune evasion mechanisms and pathogenicity determinants in rickettsiae are far from being resolved.

Cambios Cerebrales y Neuroentrenamiento. Nuevas Alternativas al Tratamiento del Dolor.

La técnica de neuroentrenamiento sensoriomotor llamada Imaginería Motora Graduada fue desarrollada por George Lorimer Moseley y, basándonos en el estudio de revisión de Priganc que integra la información acerca de esta técnica y su adaptación a la práctica, redactamos el siguiente artículo aplicándolo para el síndrome del miembro fantasma con dolor (Priganc & Stralka., 2011). Victoria Priganc es terapeuta ocupacional y de mano siendo profesora en la Universidad Rocky Mountain en Utah (Estados Unidos). Realiza sus estudios con su equipo investigador sobre Neurociencia e Imaginería Motora Graduada. Tras la pérdida de una extremidad, no es insólito experimentar dolor y/o sensaciones extrañas, tales como quemazón o calambres en la zona que ha sido retirada. ¿Cómo es posible que puedan existir percepciones de un miembro que ya no existe? El conjunto de signos y síntomas que cursa con dolor en un miembro que ya no existe se denomina síndrome de dolor del miembro fantasma, y se puede entender de la siguiente manera: El ser humano, tiene en su corteza cerebral una representación de su cuerpo físico, o lo que es lo mismo, tenemos un cuerpo virtual en nuestro cerebro. Cuando una persona pierde un miembro, este aún sigue estando representada en el cerebro, en nuestro cuerpo virtual, pero sin embargo, ya no se encuentra de manera real en nuestro cuerpo físico. “La incongruencia entre cuerpo físico y el cuerpo virtual podría tener una implicación en el dolor del paciente” Esta incongruencia, entre la extremidad que la corteza tiene representada pero que realmente ya no existe podría ser un posible mecanismo implicado en el dolor del paciente (MacIver et al., 2008). El cerebro no es una estructura estática, sino que se encuentra en continuo cambio. Tiene esa capacidad, y a este concepto, es lo que se le denomina, neuroplasticidad, es un proceso de reorganización constante. En el síndrome de dolor del miembro fantasma, esta incoherencia de la que hablábamos anteriormente, es la causante de provocar un proceso de neuroplasticidad o cambio negativo en la representación de nuestro cuerpo virtual, provocando dolor de forma mantenida. Es, por tanto, que esta reestructuración de nuestro cuerpo virtual en nuestro cerebro es la causante de que personas con miembros amputados experimenten dolor en dicho miembro, donde además se ha demostrado que, a mayor grado de dimensión en la reorganización cortical, el sujeto experimenta mayor intensidad de dolor, así como una mayor alteración de su percepción del cuerpo (Lotze et al., 2001). La Imaginería Motora Graduada, como técnica de neuroentrenamiento, permite resetear este error de congruencia entre los dos cuerpos. Es un tratamiento del cerebro y no del tejido corporal. Estos cambios neuroplásticos adaptativos o beneficiosos que se consigue con la Imaginería Motora Graduada permiten corregir las alteraciones de la percepción corporal, dando como resultado una disminución de la sintomatología del paciente. “Mediante la imaginación de movimientos indoloros y el uso de ilusiones ópticas de la extremidad perdida se podría conseguir una reestructuración a nivel cerebral, disminuyendo el dolor” El tratamiento mediante imaginería motora graduada se compone de tres etapas. En primer lugar, se encuentra la restauración de la lateralidad, que para llevarla a cabo se utilizan técnicas de visualización de imágenes que cursan con un estímulo visual. La justificación de esta primera fase, es que, estos pacientes, cursan con una pérdida de la capacidad de imaginar y reconocer si un miembro pertenece al hemisferio izquierdo o por el contrario al derecho debido al error en la reorganización subyacente al proceso del síndrome de dolor del miembro fantasma, o lo que es lo mismo, estos pacientes, si observan una mano, no pueden diferenciar si es una mano izquierda o una derecha. En segundo lugar, se encuentra la Imaginería Motora. Cuando el paciente ya es capaz de discernir entre si una mano es izquierda o por el contrario es derecha, comienza a ser capaz de imaginar acciones motoras del miembro afecto aumentando ese proceso de reorganización adaptativa y por tanto la integración de ambos hemicuerpos (lados del cuerpo). Y finalmente, se encuentra el Mirror Visual Feedback o Terapia Espejo, el cual es el último escalón en la rehabilitación, donde el paciente observa, en tiempo real, su propio miembro moviéndose gracias a un espejo donde se refleja su extremidad sana. De esta forma, engañamos al cerebro creando una ilusión óptica que provoca una mayor congruencia entre la información que el cerebro recibe del sistema visual del cuerpo real con el que tiene representado de manera virtual, disminuyendo el dolor. En conclusión, la Imaginería Motora Graduada es una técnica de neuroentrenamiento sensoriomotor utilizada en el tratamiento del síndrome de dolor del miembro fantasma, el cual cursa con un proceso de neuroplasticidad negativa que afecta a la representación del cuerpo virtual del paciente donde, mediante la imaginación de movimientos indoloros y el uso de ilusiones ópticas de la extremidad perdida, se consigue un reajuste de la incongruencia entre el cuerpo virtual y el cuerpo físico, disminuyendo el dolor.