Precipitous Fall Research Articles

Maximum 24-Hour Platelet Count Fall Rate As a Predictor of HIT

Background: Heparin-induced thrombocytopenia (HIT) is a high-stakes diagnosis. A delay in initiation of appropriate therapy is associated with a 6.1% daily incidence of thrombosis, amputation, and death (Greinacher et al, Blood 2000). However, misdiagnosis exposes patients without HIT to alternative anticoagulants and their attendant risk of major bleeding. Although a meta-analysis showed that the negative predictive value (NPV) of a low-probability 4Ts score is 99.8%, the positive predictive value (PPV) of the 4Ts score is limited. This is particularly true among individuals with an intermediate-probability score, in whom the PPV is only 14% (Cuker et al. Blood 2012). It has been observed that immune-mediated causes of thrombocytopenia result in a more precipitous fall in the platelet count than other common causes of hospital-acquired thrombocytopenia (e.g. infection, disseminated intravascular coagulation, drug-induced myelosuppression). Nevertheless, the pace of platelet count fall is not currently captured in the 4Ts score or other clinical prediction models for HIT. We hypothesized that rapidity of the platelet count fall could help to discriminate HIT status among patients with an intermediate probability 4Ts score. Methods: In a cohort of 292 patients with suspected HIT and prospectively calculated 4Ts scores, we identified patients with an intermediate 4Ts score (4 or 5). Patients were classified as HIT-positive or HIT-negative by an independent panel of HIT experts as previously described (Pishko et al. Blood Advances 2018). We compared the frequency of scores in each of the 4Ts score categories between HIT-positive and-HIT negative patients using Chi-square analysis. For each day from hospital admission to day of HIT laboratory testing, we extracted the first measured platelet count, exposure to heparin, and platelet transfusions. We also extracted the dates of the following events of interest, as they may be associated with an immediate fall in platelet count: cardiovascular surgery, initiation of extracorporeal membrane oxygenation, intra-aortic balloon pump placement, Impella device placement, and left ventricular assist device implantation. Two reviewers reviewed the platelet count and clinical data for each patient to determine the day on which the platelet count began to decline, excluding platelet count falls 24 hours following one of the aforementioned events of interest. From this date, we calculated the change in platelet count per each 24-hour timeframe, expressed as a percentage of the previous day's platelet count. For each subject, we identified the maximum percentage decrease in platelet count in a 24-hour period (Fallmax). We then compared the Fallmax between HIT-positive and HIT-negative subjects using the Wilcoxon-rank sum test. We assessed the operating characteristics of Fallmax for the diagnosis of HIT at different cut-offs. We selected a cut-off that maximized specificity of the metric while maintaining a sensitivity of ≥95%. Results: Among 292 patients, 158 (54.1%) had a 4Ts score of 4 or 5. Twenty-two (13.9%) were HIT-positive and 136 (86.1%) were HIT-negative. Patient characteristics are listed in table 1. No single item in the 4Ts score exhibited a significant relationship with HIT diagnosis (table 2). The median Fallmax was 49.6% (IQR 42.3-58.9) in HIT-positive patients and 38.5% (IQR 27.8-50.4) in HIT-negative patients (p=0.009). At a Fallmax cut off of ≥ 30%, the sensitivity and specificity of this measure for the diagnosis of HIT was 95.5% (95% CI 77.2%-99.9%) and 29.4% (95% CI 21.9%-37.8%), respectively (table 3). 29.4% (40/136) of the HIT-negative patients had a Fallmax below this cut-off versus only 2.4% (1/22) HIT-positive patients. Conclusion: The maximum percentage decrease in platelet count within 24-hours (Fallmax) was significantly higher in HIT-positive versus HIT-negative patients. A Fallmax ≥ 30% may be a useful metric to discriminate HIT positivity among patients with an intermediate 4Ts score. In this cohort, nearly 30% of HIT negative patients did not meet this cut-off and thus may have been spared alternative anticoagulant exposure. The rapidity of platelet count fall holds promise as a marker for improving the PPV of the 4Ts score, though it requires further evaluation and external validation. Disclosures Cuker: Synergy: Consultancy; Alexion: Other: Institutional funding on author's behalf; Bayer: Other: Institutional funding on author's behalf; Novo Nordisk: Other: Institutional funding on author's behalf; Pfizer: Other: Institutional funding on author's behalf; Spark: Other: Institutional funding on author's behalf. Pishko:Novo Nordisk: Research Funding; Sanofi Genzyme: Research Funding.

Intensified hydroclimatic regime in Korean basins under 1.5 and 2°C global warming

AbstractThis study assesses the potential changes in regional hydroclimates over South Korea in response to 1.5 and 2.0°C of global warming above preindustrial levels based on multimodel ensemble projections forced by a representative concentration pathway (RCP4.5) scenario. The meteorological inputs, which are derived from five global climate models after removing systematic bias using quantile mapping, are fed into a distributed hydrological model, the variable infiltration capacity model, to estimate the hydrologic responses to different levels of greenhouse gas concentrations in future periods. The changes in seasonal mean precipitation differ between monsoon and intermonsoon seasons. An increase in summer precipitation and a decrease in winter precipitation commonly occur under 1.5 and 2.0°C of global warming, resulting in intensified precipitation seasonality. However, changes in spring and fall precipitation show opposite change signals or relatively little robustness (as measured by model agreement) in response to different degrees of warming. Spatial and seasonal changes in precipitation are directly transferred to runoff patterns, increasing the disparity between wet and dry seasons. Global warming also leads to changes in the distributions of daily precipitation and streamflow, and the projected changes systematically involve an increase in high‐intensity precipitation and a decrease in relatively low‐intensity precipitation. This behaviour tends to be amplified under 2.0°C in comparison to 1.5°C of global warming, with potential implications for increased water stress under a much warmer climate. More importantly, under 2.0°C of global warming, the magnitude of extremes such as the annual maximum day flow in Korean basins is likely to be enhanced. This study demonstrates that changes in precipitation characteristics can explicitly modulate runoff and subsequently streamflow patterns, suggesting positive benefits of half a degree less warming in terms of the frequency and intensity of extreme streamflow.

Extreme rainfall in Mediterranean France during the fall: added value of the CNRM-AROME Convection-Permitting Regional Climate Model

South-East France is a region often affected by heavy precipitating events the characteristics of which are likely to be significantly impacted in the future climate. In this study, cnrm-arome, a Convection-Permitting Regional Climate Model with a 2.5 km horizontal resolution is compared to its forcing model, the Regional Climate Model aladin-climate at a horizontal resolution of 12.5 km, self-driven by the era-interim reanalysis. An hourly observation dataset with a resolution of 1 km, comephore, is used in order to assess simulated surface precipitation from a seasonal to hourly scale. The representation of the spatial pattern of fall precipitation climatology is improved by cnrm-arome. It also shows a clear added value with respect to aladin-climate through the improvement of the localization and intensity of extreme rainfall on a daily and hourly time scale on both fine and coarse spatial scales (2.5, 12.5 and 50 km). cnrm-arome in particular is able to simulate intense rainfall on lowlands and makes sub-daily rainfall events more intense than aladin-climate. cnrm-arome still underestimates very extreme precipitation from above 30 mm/h or 230 mm/day.

Increased Fall Precipitation in the Southeastern United States Driven by Higher‐Intensity, Frontal Precipitation

AbstractDuring 1895‐2018, fall precipitation increased by nearly 40% in the southeastern United States north of the Gulf of Mexico due to increased circulation around the western North Atlantic Subtropical High, which enhanced moisture transports into the region. We find here that these increases in southeastern U.S. fall precipitation manifested almost entirely as increases in precipitation intensity, not frequency. Further, the enhanced moisture transports increased precipitation totals far more on the highest‐intensity precipitation days than on the lower‐intensity days, leading to nearly all of the increase to be delivered on extreme (top‐5% intensity) precipitation days. Eighty‐seven percent of the fall precipitation increase was driven by non‐tropical storms (mostly frontal), not tropical cyclones, though the proportion of precipitation falling as either storm type did not change. Further research is needed to evaluate whether these observed precipitation increases are likely to continue, stabilize, or reverse.

Climate, Fascism, and Ibex: Experiments in Using Population Dynamics Modeling as a Historiographical Tool

In the interwar years the Gran Paradiso ibex population followed two subsequent, contrasting trends: a steady rise once the national park was established in 1922, followed by a precipitous fall after the Fascist regime took direct control of conservation in 1934, which almost led to the colony’s extinction. This paper addresses the issue of how models taken from population ecology may inform historical narratives. The data for the interwar years were analyzed using a statistical model based on climate and population density, which has proved reliable for most of the post-World War II period. The article highlights the pivotal role of anthropic variables in determining the inter-war trends and how these are best analyzed using historical scholarship.

Microphysical characteristics of a convective precipitation system observed on July 04, 2012, over Mt. Halla in South Korea

During the 2012 Changma season of June and July, we conducted an intensive field observation to investigate the microphysical characteristics of orographic precipitation that passed around Mt. Halla (oriented west–east; height: 1950 m; width: 78 km; length: 35 km) in South Korea's Jeju Island. On July 04, 2012, Jeju Island experienced a convective precipitation system that developed in the southern part of a stationary front. With the goal of understanding the microphysical process of this system (precipitation intensity: 70 mm h−1), we collected detailed data using 7 Parsivel disdrometers, a ground-based dual S-band Doppler radar, and GPS sounding. The convective precipitation developed in a considerably warm and moist environment (near-surface relative humidity: 94%) with dominant southwesterly winds of 4.7 m s−1 at low altitudes. The convective region was formed by a combination of coastal ascending air and considerably warm and moist low-level marine inflow. The coastal warm and moist ascending air activates the warm rain process of moisture uptaken from sea surface, increasing the concentration of large-sized raindrops (diameter: ≥ 5 mm). The continuous development of a convective region extending from the foothill to the upslope highlights that the convective updrafts continuously supply low-level moisture to the convective region. This influx of moisture and the condensation of small-, middle-, and large-sized raindrops combine to create a significant concentration of large-sized raindrops along the upslope of the mountain. Around the mountaintop, the fall of precipitation drives the breakup process aided by convective ascending airs, increasing the concentrations of small-sized raindrops. On the leeward side, the existence of orographically generated stationary wind convergences is notable. As a result and the marine inflow along the southeastern gentle slope, i.e., the convective region, continues to develop, thereby activating cold rain processes. This study sheds light on the variety of raindrop size distributions and moisture processes at locations relative to a single-peak mountain leading to localized heavy precipitation during the passage of an isolated convective precipitation event.

Ants, wind, and low litter deposition contribute to the maintenance of fire-protective clearings around Jeffrey pine (Pinus jeffreyi)

In Jeffrey pine (Pinus jeffreyi) forests, which once supported a frequent, mostly low severity fire regime, fire suppression has led to notable changes in forest structure and fuel loads. In parts of California, prescribed fire has been used to decrease fuel loads and reduce the risk of high intensity fire in these forests. Previous work has shown that circular litter-free clearings form around Jeffrey pine trees following prescribed burns and that they can reduce tree damage and potentially increase the chance of survival in a subsequent wildfire. In this study we aim to determine the factors responsible for maintaining clearings around trees after a fire occurs. Using a set of field experiments and observational studies, we show that a combination of natural processes, including reduced litter deposition near trees, and the movement of needles away from trees by ants (Formica sibylla) and wind, reduce the amount of litter near trees and likely contribute to the long-term maintenance of clearings. Stem flow resulting from rare heavy rain events also appears to play a role in clearing maintenance. All of the abiotic factors investigated interact with the physical structure of the tree to remove pine needles from the bases of trees, but ants move needles independently to facilitate clearing maintenance and indirectly enhance tree fitness when fires occur. Given how generally common F. sibylla is in Jeffrey pine habitat and the relative stability of the abiotic processes that also contribute to maintaining clearings (wind, precipitation, and needle fall), we may expect to see clearings form in other Jeffrey pine forests after prescribed fires are introduced.

Follicular dynamics and colour Doppler vascularity evaluations of follicles and corpus luteum in relation to plasma progesterone during the oestrous cycle of Surti buffaloes.

With an objective to evaluate the follicular dynamics and vascularity changes in follicles and corpus luteum, the ovaries of cyclic Surti buffaloes (n=9) were examined daily sequentially by transrectal B-mode and colour flow mode (CFM) ultrasonography starting from the day of oestrus till the onset of next oestrus. Higher proportion of buffaloes evidenced one-wave cycle (66.66%) compared to two-wave cycle (33.34%) with none showing a three-wave cycle. The dominant follicle of the first follicular wave was the ovulatory follicle and persisted for 19.70±0.50days compared to its persistence for 16.5±1.45days in a two-wave cycle. The maximum diameter of the ovulatory follicle in a one-wave and two-wave cycle did not differ yet their linear growth rates were significantly lower (p<0.01) in a one-wave cycle. Colour flow mode examination of follicles revealed that the percentage of follicles with detectable blood flow in the subsequently determined largest follicle (dominant follicle) was not different from that in the second largest follicle before follicle deviation. The blood flow in the dominant follicle increased significantly on the day of oestrus. The mean diameter and blood flow to the corpus luteum (CL) increased linearly and significantly from Day 5 of oestrus till Day 13 after which both parameters started declining. At or around Day 16, there was precipitous fall in the blood supply to the CL and CL diameter that continued declining thereafter to reach the lowest around Day 20 of the oestrous cycle. Rise in plasma progesterone concentrations was synchronous to CL diameter and vascularity and showed significant and positive correlations. It was concluded that Surti buffaloes evidence a preponderance of one-wave follicular growth pattern with a significant increase in the vascularity of ovulatory follicle on the day of oestrus and corpus luteum on Day 13 of the oestrous cycle.

Cardiac arrest following protamine administration: a case series

Protamine sulfate is commonly used to reverse the action of heparin after catheter ablation procedures. Serious protamine-related adverse effect is rare, but its recognition and appropriate management by electrophysiologists and intensivists is important. Direct ventricular fibrillation (VF) soon after a slow infusion of protamine has not been clearly described. We examined the records of all patients who suffered apparent adverse events after protamine administration in our electrophysiology lab from 2013 to 2018. We describe a series of three patients, all of whom suffered a precipitous fall in arterial pressure followed by VF within minutes after administration of protamine following ablation for atrial fibrillation. The same supplier of protamine was used in all three cases, but they were from different batches. Serum tryptase levels were measured in all cases, immediately post-cardiac arrest and at 2- and 6-h post-event. Immunoglobulin levels were not measured. Two patients recovered after aggressive supportive therapy; the third died despite similar support. We have encountered three cases of profound hypotension followed by VF soon after administration of protamine. Although protamine is safe in a large majority of patients, these adverse events have led our centre to exercise greater selectivity and caution in its use.

The Structure of Prices in the Ur III Economy: Cults and Prices at the Collapse of the Ur III State

The production of a barley surplus by the Ur III economy was vital for the operation of its commodity money system. The standardizing bi-monetary equivalence of a gur measure of barley and a shekel of silver stabilized commodity prices for the thirty-five years before the reign of Ibbi-Suen. In Ibbi-Suen’s early years, the collapse of the barley supply induced an excessive devaluation of the barley to silver ratio leading to a near hyperinflation in the prices of staple commodities and bovids required for cult and other purposes. This article analyzes the inflation in prices of animals and staples correlated with the precipitous fall in the barley to silver price ratio. Data is primarily from the Ur texts dated to the seventh year of Ibbi-Suen’s reign concerned with the purchase and delivery to state institutions of animals. Importantly, an analysis of these events demonstrated the central function of a barley surplus in the Ur III monetary system.

Promoting Arts and Crafts of the Country through Use of Indigenous Products

Recent years have seen a precipitous fall in the demand and market for India's traditional handicrafts, arts, and textiles. Genericide in the arts and crafts industry is harmful to indigenous and traditional handicraft enterprises because to the rising popularity of machine-made items via internet shopping and a lack of oversight for product quality. Indian artists and craftspeople face decreasing income and customer demand as a result of the country's poor performance in competitiveness criteria such basic infrastructure, intellectual property rights, education, and broadband adoption. This report analyzes problems encountered by indigenous art and craft vendors and suggests solutions to help the industry thrive. In addition to having a negative effect on the sector's economy, the report concludes that Genericide is also damaging the reputation of Indian Indigenous Arts and Crafts as a whole. As a means of combating "Genericide" and stemming the tide of escalating hyper-competition, the use of Geographical Indications has been recommended.

Investigating the causes of increased 20th-century fall precipitation over the southeastern United States.

Much of the eastern United States (US) experienced increased precipitation over the 20th century. Characterizing these trends and their causes is critical for assessing future hydroclimate risks. Here, US precipitation trends are analyzed during 1895-2016, revealing that fall precipitation in the southeastern region north of the Gulf of Mexico (SE-Gulf) increased by nearly 40%, primarily increasing after the mid-1900s. As fall is the climatological dry season in the SE-Gulf and precipitation in other seasons changed insignificantly, the seasonal precipitation cycle diminished substantially. The increase in SE-Gulf fall precipitation was caused by increased southerly moisture transport from the Gulf of Mexico, which was almost entirely driven by stronger winds associated with enhanced anticyclonic circulation west of the North Atlantic Subtropical High (NASH) and not by increases in specific humidity. Atmospheric models forced by observed SSTs and fully-coupled models forced by historical anthropogenic forcing do not robustly simulate 20th-century fall wetting in the SE-Gulf. SST-forced atmospheric models do simulate an intensified anticyclonic low-level circulation around the NASH, but the modeled intensification occurred farther west than observed. CMIP5 analyses suggest an increased likelihood of positive SE-Gulf fall precipitation trends given historical and future GHG forcing. Nevertheless, individual model simulations (both SST-forced and fully-coupled) only very rarely produce the observed magnitude of the SE-Gulf fall precipitation trend. Further research into model representation of the western ridge of the fall NASH is needed, which will help us better predict whether 20th-century increases in SE-Gulf fall precipitation will persist into the future.

Patterns and drivers of long‐term changes in breeding bird communities in a global biodiversity hotspot in Mexico

AbstractAimTo evaluate changes in breeding bird communities and assess implications for conservation.LocationMadrean Sky Islands and northern Sierra Madre Occidental, Mexico.MethodsI compared observations from recent fieldwork (2009–2012) with an extensive historical data set (1887–1954) and used modelling and multivariate techniques to assess spatiotemporal changes in species occurrence, richness and assemblage composition, and associations with climate, land use and landscape factors.ResultsBreeding species richness peaked in larger ranges often in the south and east, and regional beta diversity was attributable much more to turnover (0.80) than nestedness (0.07). Although richness increased across time, spatial assemblage heterogeneity declined due only to changes in nestedness, with temporal shifts in beta diversity equally attributable to variation in nestedness and turnover. Community change was associated with variation in climate, land use and landscape factors in ways that depended on species’ traits. Major gains in Madrean and lowland Neotropical species from the south contrasted little change in Nearctic species, and there was some evidence lowland species expanded eastward into the higher‐elevation interior, suggesting poleward and up‐elevation shifts now occurring globally. Some such patterns were associated with increasing temperature and summer–fall precipitation typical of the south suggesting climate forcing. Despite regional gains in pine‐dependent species linked to post‐logging forest recovery, losses and turnover were greater in smaller more arid ranges due likely to climate‐mediated habitat loss. High regional losses of cavity‐nesting species in forest were greater in ranges subjected to past logging indicating effects of historical habitat degradation persist today.Main conclusionDespite ongoing forest recovery and potential for northward range expansion to offset climate‐mediated losses of montane species, further assemblage homogenization seems likely. Active forest restoration that promotes large old trees, snags and mature forest conditions combined with increasing the capacity of local communities to implement best management practices will enhance conservation.

How mesh became a four letter word

Jonathan Gornall charts the rapid rise and precipitous fall of vaginal mesh—a story that offers lessons for the entire medical community, and for manufacturers and regulators

Variability, teleconnection, and predictability of Korean precipitation in relation to large scale climate indices

Spatiotemporal variability, teleconnection, and predictability of the Korean precipitation related to large scale climate indices were examined based on leading patterns of observed monthly Rx5day and total precipitation through an empirical orthogonal teleconnection (EOT). Cross-correlation and lag regression analyses for the leading modes and global atmospheric circulation dataset were employed on a monthly basis. The spatial pattern of the leading EOT modes for Rx5day and total precipitation represents a northern inland mode for boreal summer and a southern coastal mode in boreal winter. The temporal evolution of the leading EOT modes exhibits increasing trends during summer season and decadal variability for winter season. The leading EOT patterns of Rx5day precipitation show more widespread coherent patterns than those of total precipitation during warm and cold seasons, while the former explains less variance in precipitation variability than the latter. The tropical ENSO forcing has a coherent teleconnection with September and November-December precipitation patterns, while the Indian Ocean dipole is identified as a driver for precipitation variability in September and November. The monsoon circulation over the western North Pacific also exhibits a significant negative correlation with winter precipitation EOTs, while tropical cyclone indices are positively correlated with the fall precipitation EOTs. The leading patterns of the September and December Rx5day precipitation time series are predictable at up to six month lead time from the tropical Pacific sea surface temperatures (SSTs), while a somewhat weak predictable response from Indian Ocean SSTs was only detected at longer lead times. In addition, predictability from the Pacific SSTs for above normal precipitation is greater than that for below normal precipitation.

Factors influencing Northern Bobwhite recruitment, with implications for population growth

Understanding and quantifying demographic parameters that influence population growth is necessary to effectively maintain population persistence in the presence of recent changes in climate and land use. We used a combination of capture–recapture and harvest information from a 42 yr dataset to create an integrated population model that estimates population abundance, annual survival, and per capita recruitment in Northern Bobwhite (Colinus virginianus). We evaluated the associations of commonly reported population metrics (age ratios from harvests, annual survival, and recruitment) to population growth rate using correlation analysis. We also modeled the effects of population abundance, breeding-season temperature, breeding-season precipitation, fall minimum temperature, and fall precipitation on recruitment. Recruitment averaged 1.55 (range: 0.82–2.21) and was most strongly correlated with population growth (r = 0.78, 95% confidence interval [CI]: 0.63–0.88), followed by annual survival (r = 0.38, 95% CI: 0.09–0.61). We found a weak correlation between fall age ratios and population growth rate (r = 0.11, 95% CI: −0.19 to 0.40). Recruitment exhibited weak, nonlinear, negative density dependence (β1 = −0.13, 95% credible intervals [CRI]: −0.17 to −0.08 and β2 = −0.03, 95% CRI: −0.07 to 0.004). Breeding-season maximum temperature and breeding-season precipitation had a significant, positive effect on recruitment (β3 = 0.15, 95% CRI: 0.11–0.19 and β4 = 0.10, 95% CRI: 0.05–0.16, respectively). Fall minimum temperature and fall precipitation both had negative but uncertain effects on recruitment (β5 = −0.03, 95% CRI: −0.08 to 0.01 and β6 = −0.02, 95% CRI: −0.07 to 0.01, respectively) but less so compared to weather in the breeding season. Our results illustrate that recruitment (1) can be estimated without data on fecundity and chick survival by using integrated population models and (2) is highly correlated with population growth in Northern Bobwhites. We encourage natural resource managers to focus on actions that increase Northern Bobwhite recruitment.

Climate Change Impacts on Farmland Values in the Southeast United States

This study uses the Ricardian (hedonic) approach to estimate the impact of potential climate change on agricultural farmland values in the Southeast U.S. as a distinct agricultural region. Using the Agricultural Resource Management Survey and seasonal county-level climate and data, we find that regional farmland values increase with spring and fall temperatures and fall precipitation and decrease with winter and summer temperatures. Long-term climate change projections predict aggregate farmland value losses of 2.5–5% with differential state-level impacts, ranging from large losses in Florida to significant gains in Virginia. The results are consistent with recent research and can be helpful in policy design and forecasting land use change.

Spatiotemporal Distribution and Environmental Drivers of Barley yellow dwarf virus and Vector Abundance in Kansas.

Several aphid species transmit barley yellow dwarf, a globally destructive disease caused by viruses that infect cereal grain crops. Data from >400 samples collected across Kansas wheat fields in 2014 and 2015 were used to develop spatiotemporal models predicting the extent to which landcover, temperature and precipitation affect spring aphid vector abundance and presence of individuals carrying Barley yellow dwarf virus (BYDV). The distribution of Rhopalosiphum padi abundance was not correlated with climate or landcover, but Sitobion avenae abundance was positively correlated with fall temperature and negatively correlated to spring temperature and precipitation. The abundance of Schizaphis graminum was negatively correlated with fall precipitation and winter temperature. The incidence of viruliferous (+BYDV) R. padi was positively correlated with fall precipitation but negatively correlated with winter precipitation. In contrast, the probability of +BYDV S. avenae was unaffected by precipitation but was positively correlated with fall temperatures and distance to forest or shrubland. R. padi and S. avenae were more prevalent at eastern sample sites where ground cover is more grassland than cropland, suggesting that grassland may provide over-summering sites for vectors and pose a risk as potential BYDV reservoirs. Nevertheless, land cover patterns were not strongly associated with differences in abundance or the probability that viruliferous aphids were present.

Climate-sensitive radial increment model of Norway spruce in Tyrol based on a distributed lag model with penalized splines for year-ring time series

A novel methodological framework is presented for climate-sensitive modeling of annual radial stem increment using year-ring width time series. The approach is based on a generalized additive model with penalized regression splines together with a distributed time lag model taking into account smooth nonlinear effects of a series of monthly temperature and precipitation values, as well as their interactions. Climate effects are also assumed to vary smoothly with time lag. The model framework enables both the detrending of the individual time series and the regression modeling to be performed simultaneously in a single model step. The approach is applied to year-ring width time series of Norway spruce (Picea abies (L.) H. Karst.) trees in Tyrol, Austria. The marginal response curves show that tree growth is mainly promoted by high temperatures in late spring and early summer and by precipitation in fall and winter. Summer drought does not have a negative influence on the current year’s radial increment; however, when it is associated with high temperatures, it lowers the increment in the subsequent growth period. Higher winter precipitation in conjunction with lower temperatures has a positive effect. A significant non-climate related long-term growth trend is demonstrated, probably reflecting NOx and SO2 emission trends in Austria.

Climatic Drivers of Ponderosa Pine Growth in Central Idaho

Despite the widespread use of ponderosa pine as an important hydroclimate proxy, we actually understand very little about its climate response in the Northern Rockies. Here, we analyze two new ponderosa pine chronologies to investigate how climate influences annual growth. Despite differences in precipitation amount and timing and large elevation differences (1820 m versus 1060 m), ring width at both sites was strongly driven by water availability. The mid-elevation, water-limited site responded well to previous fall precipitation whereas the wetter, high-elevation site responded to growing season precipitation and temperature. When precipitation and temperature were simultaneously accounted for using the standardized precipitation evapotranspiration index, ring-width response between sites converged and appeared nearly identical. Water stress drove the timing of ponderosa pine growth by a combination of factors such as strong water dependence, and determinate growth physiology, as indicated by lag-1 autocorrelation. When analyzing response to single-month climate variables, precipitation from growing-season months dominates. When we examined seasonal variables, climate from the previous year became more important. Temporal fidelity of the climatic response at both sites maintained significance across the historical record, although the relationship weakened at the low-elevation site. The collection of new tree-ring data sets such as these for central Idaho improves our understanding of ponderosa pine growth response to climate.