Forecasting and Analyzing Economic Activity with Coincident and Leading Indexes: The Case of Connecticut

We develop coincident and leading employment indexes for the Connecticut economy. Four employment-related variables enter the coincident index while five employment-related variables enter the leading index. The peaks and troughs in the leading index lead the peaks and troughs in the coincident index by an average of 3 and 9 months. Finally, we use the leading index in vector-autoregressive (VAR) and Bayesian vector-autoregressive (BVAR) models to forecast the coincident index, nonfarm employment, and the unemployment rate.

{[N.N.], Szenenfoto, Gruppenbildnis, in: Igor Stravinsky: The Flood, Hamburg: Staatsoper, 1963, Inszenierung: Günther Rennert

Signatur des Originals: S 36/F11346

A comparison of techniques for forecasting utilization of Veterans Affairs hospitals

This study demonstrated that accurate, short-term forecasts of Veterans Affairs (VA) hospital utilization can be made using the Patient Treatment File (PTF), the inpatient discharge database of the VA. Accurate, short-term forecasts of two years or less can reduce required inventory levels, improve allocation of resources, and are essential for better financial management. These are all necessary achievements in an era of cost-containment.^ Six years of non-psychiatric discharge records were extracted from the PTF and used to calculate four indicators of VA hospital utilization: average length of stay, discharge rate, multi-stay rate (a measure of readmissions) and days of care provided. National and regional levels of these indicators were described and compared for fiscal year 1984 (FY84) to FY89 inclusive.^ Using the observed levels of utilization for the 48 months between FY84 and FY87, five techniques were used to forecast monthly levels of utilization for FY88 and FY89. Forecasts were compared to the observed levels of utilization for these years. Monthly forecasts were also produced for FY90 and FY91.^ Forecasts for days of care provided were not produced. Current inpatients with very long lengths of stay contribute a substantial amount of this indicator and it cannot be accurately calculated.^ During the six year period between FY84 and FY89, average length of stay declined substantially, nationally and regionally. The discharge rate was relatively stable, while the multi-stay rate increased slightly during this period. FY90 and FY91 forecasts show a continued decline in the average length of stay, while the discharge rate is forecast to decline slightly and the multi-stay rate is forecast to increase very slightly.^ Over a 24 month ahead period, all three indicators were forecast within a 10 percent average monthly error. The 12-month ahead forecast errors were slightly lower. Average length of stay was less easily forecast, while the multi-stay rate was the easiest indicator to forecast.^ No single technique performed significantly better as determined by the Mean Absolute Percent Error, a standard measure of error. However, Autoregressive Integrated Moving Average (ARIMA) models performed well overall and are recommended for short-term forecasting of VA hospital utilization. ^

Predicting the Past and Forecasting the Future

A commentary on Santos' article, "Explaining Scholarship Addressing Hispanic Children’s Issues."

Occurence of flood laminae in sediments of Ammersee

A 450 year spring-summer flood layer time series at seasonal resolution has been established from the varved sediment record of Lake Ammersee (southern Germany), applying a novel methodological approach. The main results are (1) the attainment of a precise chronology by microscopic varve counting, (2) the identification of detrital layers representing flood-triggered fluxes of catchment material into the lake, and (3) the recognition of the seasonality of these flood layers from their microstratigraphic position within a varve. Tracing flood layers in a proximal and a distal core and correlating them by application of the precise chronology provided information on the depositional processes. Comparing the seasonal flood layer record with daily runoff data of the inflowing River Ammer for the period from 1926 to 1999 allowed the definition of an approximate threshold in flood magnitude above which the formation of flood layers becomes very likely. Moreover, it was possible for the first time to estimate the "completeness" of the flood layer time series and to recognize that mainly floods in spring and summer, representing the main flood seasons in this region, are well preserved in the sediment archive. Their frequency distribution over the entire 450 year time series is not stationary but reveals maxima for colder periods of the Little Ice Age when solar activity was reduced. The observed spring-summer flood layer frequency further shows trends similar to those of the occurrence of flood-prone weather regimes since A.D. 1881, probably suggesting a causal link between solar variability and changes in midlatitude atmospheric circulation patterns.

Organic geochemistry of water and bottom sediments during a seasonal flood in 2006 in the North Dvina River estuary

Heavy contaminant load released into the Northern Dvina River during flooding increased the concentrations of aliphatic (AHC) and polcyclic aromatic (PAH) hydrocarbons in water and bottom sediments. The composition of hydrocarbons was different from that of the summer low flow season. The concentrations of dissolved and particulate AHC ranged from 12 to 106 and from 192 to 599 µg/l, respectively, and bottom sediments contained from 26.2 to 329 µg/g AHC and 4 to 1785 ng/g PAH. As the transformation of AHC occurred at low spring temperatures, the alkane composition was shown to be dominated by terrigenous compounds, whereas more stable PAH showed elevated contents of petrogenic and pyrogenic compounds. It was also shown that the Northern Dvina-Dvina Bay geochemical barrier prevents contaminant input into the White Sea, i.e., acts as a marginal filter.

Occurence and thickness of flood layers in varved sediments of Lake Ammersee

Microfacies analyses and X-ray fluorescence scanning (µ-XRF) at sub-mm resolution were conducted on the varved Mid- to Late Holocene interval of two sediment profiles from pre-alpine Lake Ammersee (southern Germany). The coring sites are located in a proximal (AS10prox) and distal (AS10dist) position towards the main tributary River Ammer, in 1.8 km distance from each other. To shed light on sediment distribution within the lake, particular emphasis was (1) the detection of intercalated detrital layers and their micro-sedimentological features, and (2) intra-basin correlation of these event deposits. Detrital layers were dated by microscopic varve counting, verified by accelerator mass spectrometry 14C dating of terrestrial plant macrofossils. Since ~5500 varve years (vyr) BP, in total 1573 detrital layers were detected in either one or both of the investigated sediment profiles. Based on their microfacies, geochemistry, and proximal-distal deposition pattern, detrital layers were interpreted as River Ammer flood deposits. Earlier studies on flood layer seasonality have proven that flood layer deposition occurs predominantly during spring and summer, the flood season at Lake Ammersee. Most prominent features of the record are the onset of regular flood layer deposition at ~5500 vyr BP in AS10prox and ~ 2800 vyr BP in AS10dist as well as three major increases in mean flood layer thickness at ~5500, 2800, and 400 vyr BP. Integrating information from both sediment profiles allowed to interpret these changes in terms of shifts towards higher mean flood intensity. Proposed triggering mechanisms are gradual reduction in Northern Hemisphere orbital summer forcing and superimposed centennial-scale solar activity minima. Likely responses to this forcing are enhanced equator-to-pole temperature gradients and changes in synoptic-scale atmospheric circulation. The consequences for the Ammersee region are more intense cyclones leading to extremer rainfall and flood events in spring and summer.

Geochemistry of oceanic flood basalts from the Caribbean plate

The thick oceanic crust of the Caribbean plate appears to be the tectonized remnant of an eastern Pacific oceanic plateau that has been inserted between North and South America. The emplacement of the plateau into its present position has resulted in the obduction and exposure of its margins, providing an opportunity to study the age relations, internal structure and compositional features of the plateau. We present the results of 40Ar-39Ar radiometric dating, major-, trace-element, and isotopic compositions of basalts from some of the exposed sections as well as drill core basalt samples from Leg 15 of the Deep Sea Drilling Project. Five widely spaced, margin sections yielded ages ranging from 91 to 88 Ma. Less well-constrained radiometric ages from the drill cores, combined with the biostratigraphic age of surrounding sediments indicate a minimum crystallization age of ~90 Ma in the Venezuelan Basin. The synchroneity of ages across the region is consistent with a flood basalt origin for the bulk of the Caribbean plateau i.e., large volume, rapidly erupted, regionally extensive volcanism.. The ages and compositions are also consistent with plate reconstructions that place the Caribbean plateau in the vicinity of the Galápagos hotspot at its inception. The trace-element and isotopic compositions of the ~90 Ma rocks indicate a depleted mantle and an enriched, plume-like mantle were involved in melting to varying degrees across the plateau. Within the same region, a volumetrically secondary, but widespread magmatic event occurred at 76 Ma, as is evident in Curacao, western Colombia, Haiti, and at DSDP Site 152/ODP Site 1001 near the Hess Escarpment. Limited trace-element data indicate that this phase of magmatism was generally more depleted than the first. We speculate that magmatism may have resulted from upwelling of mantle, still hot from the 90 Ma event, during lithospheric extension attending gravitational collapse of the plateau, andror tectonic emplacement of the plateau between North and South America. Still younger volcanics are found in the Dominican Republic (69 Ma) and the Quepos Peninsula of Costa Rica (63 Ma). The latter occurrence conceivably formed over the Galápagos hotspot and subsequently accreted to the western edge of the plateau during subduction of the Farallon plate.

Hydrocarbons in bottom sediments during a seasonal flood 2005 in the Dvina River estuary

The results of studying hydrocarbons during the flood in May 2005 are discussed. The concentration of aliphatic and polycyclic aromatic hydrocarbons are shown to match their concentrations in water areas with steady input of pollutants. Weathered oil and pyrogenic compounds dominated in their composition. The geochemical barrier the Northern Dvina River-Dvina Gulf is shown to become a filter during floods and prevents pollutants from penetrating into the White Sea.