Pre-change Period Research Articles

Climate and agricultural land use change impacts on streamflow in the upper midwestern United States

AbstractIncreased streamflow and its associated impacts on water quality have frequently been linked to changes in land use and land cover (LULC) such as tile drainage, cultivation of prairies, and increased adoption of soybeans (Glycine max) in modern day cropping systems. This study evaluated the relative importance of changes in precipitation and LULC on streamflow in 29 Hydrologic Unit Code 008 watersheds in the upper midwestern United States. The evaluation was done by statistically testing the changes in slope and intercept of the relationships between ln(annual streamflow) versus annual precipitation for the periods prior to 1975 (prechange period) and after 1976 (postchange period). A significant shift either in slope or intercept of these relationships was assumed to be an indication of LULC changes whereas a lack of significant shift suggested a single relationship driven by precipitation. All 29 watersheds showed no statistical difference in slope or intercept of the relationships between the two periods. However, a simpler model that kept the slope constant for the two periods showed a slight upward shift in the intercept value for 10 watersheds in the postchange period. A comparison of 5 year moving averages also revealed that the increased streamflows in the postchange period are mainly due to an increase in precipitation. Minimal or the lack of LULC change impact on streamflow results from comparable evapotranspiration in the two time periods. We also show how incorrect assumptions in previously published studies minimized precipitation change impacts and heightened the LULC change impacts on streamflows.

Runoff changes and their potential links with climate variability and anthropogenic activities: a case study in the upper Huaihe River Basin, China

The impacts of climate variability and anthropogenic activities on hydrological processes have been of wide concern in the hydrology community during recent decades. In this study, specific investigations of individual impacts of climate variability and anthropogenic activities on runoff during 1964–2010 are conducted for the upper Huaihe River Basin at Huaibin (HB) and its five sub-catchments. The non-stationary relationship between precipitation and runoff was firstly analyzed, and according to change point detection results, long-term series for each catchment was divided into pre-change period and post-change period, respectively. Then, the climate variability and human activities that occurred in the whole HB catchment were analyzed. Finally, using two quantitative evaluation methods, the individual impacts of climate variability and human activities for each catchment were assessed. The results showed that for the whole HB catchment, runoff changes during the whole post-change period are mainly attributed to climate variability, as for its sub-catchments except the Xinxian catchment. As for decadal behaviors, runoff generally suffered more human-induced impacts in dry decades (1990s) than wet decades (1980s and 2000s). These results reflected the complex role of climate variability and human activities in influencing the runoff regime, which could be considered in local water resources management.

The Effect of Corporate Debt on Default Risk

The purpose of this study is to examine if there is any systematic relationship between the default risk and financial performance. From analytical results, this study develops the hypothesis by comparing the financial performance between pre-change and post-change period, using a sample of 173 Korean firms that experienced changes in their capital structures through the issue of debt during 2001-2010 period. The empirical results indicate that the financial performance has decreased for the issue of new debt from pre-change to post-change period, but the issue of debt is positively related to the cost of capital. These results hold up even after controlling for the differences in the financial leverage and size between pre-change and post-change period. Overall, the findings provide directly support to the hypothesis that the issue of debt is a negative function of the firm"s financial performance as measured by the firm’s profitability( ROA) and WACC.

Restrictions in pub closing times and lockouts in Newcastle, Australia five years on

In 2008 pub closing times were restricted from 5 am to 3:30 am in the central business district (CBD) of Newcastle, Australia. A previous study showed a one-third reduction in assaults in the 18 months following the restriction. We assessed whether the assault rate remained lower over the following 3.5 years and whether the introduction of a 'lockout' in nearby Hamilton was associated with a reduction in assaults there. We used a pre-post design with comparison against two post-change periods. The setting was Greater Newcastle (population 530,000) and subjects were persons apprehended for assault in the CBD and nearby Hamilton, an area with late trading pubs where a lockout and other strategies were implemented in 2010. Cases were police-recorded assault apprehensions occurring from 10 pm to 6 am in one pre-change period: January 2001 to March 2008, and two post-change periods: (i) April 2008 to September 2009 and (ii) October 2009 to March 2013. Negative binomial regression with terms for secular trend and seasonal effects was used to estimate Post1: Pre and Post2: Pre Incidence Rate Ratios and confidence intervals. In the CBD recorded assaults fell from 99/quarter before the restriction to 68/quarter in the first post-change period [incidence rate ratio (IRR) 0.67, 95% confidence interval (CI) 0.55-0.82] and 71/quarter (IRR: 0.68, 95% CI: 0.55-0.85) in the later post-change period. In the same periods in Hamilton, assault rates were 23, 24, and 22 per quarter respectively. The restriction in closing time was associated with a sustained lower assault rate in the Newcastle CBD. We find no evidence that lockouts and other outlet management strategies were effective in Hamilton.

Quantitative assessment of the impact of climate variability and human activities on runoff changes for the upper reaches of Weihe River

In the wake of global and regional climate change and heightened human activities, runoff from some rivers in the world, especially in the arid and semi-arid regions, has significantly decreased. To reveal the varying characteristics leading to the change in runoff, detecting the influencing factors has been important in recent scientific discussions for water resources management in drainage basins. In this paper, an investigation into attributing the runoff response to climate change and human activities were conducted in two catchments (Wushan and Shetang), situated in the upper reaches of Weihe River in China. Prior to the identification of the factors that influenced runoff changes, the Mann–Kendall test was adopted to identify the trends in hydro-climate series. Also, change-points in the annual runoff were detected through Pettitt’s test and the precipitation–runoff double cumulative curve method. It is found that both catchments presented significant negative trend in annual runoff and the detected change-point in runoff occurs in 1993. Hence, the pre-change period and post-change period are defined before and after 1993, respectively. Then, runoff response to climate change and human activities was quantitatively evaluated on the basis of hydrologic sensitivity analysis and hydrologic model simulation. They provided similar estimates of the percentage change in mean annual runoff for the post-change period over the considered catchments. It is found that the decline in annual runoff over both catchments can be mainly attributed to the human activities, the reduction percentages due to human activities range from 59 to 77 %. The results of this study can provide a reference for the development, utilization and management of the regional water resources and ecological environment protection.

Implementation of a continuous admission model reduces the length of stay of patients on an internal medicine clinical teaching unit

Optimizing hospital operations is a critical issue facing healthcare systems. Reducing unnecessary variation in patient flow is likely to improve efficiency and optimize capacity for hospital inpatients. The objective of this study was to determine whether changing admissions, from a "bolus" system to a "drip" system, would result in a smoothed daily discharge rate, and reduce the length of stay of patients on a General Internal Medicine clinical teaching unit over a period of 1 year. We conducted a retrospective analysis of the General Internal Medicine inpatient service at Toronto General Hospital for the 6-month periods from March to August during 2 consecutive years. Length of stay distributions and daily discharge rate variations were compared between the 2 study periods. There were a total of 2734 discharges, 1446 occurring in the pre-change period, and 1288 in the post-change period. There was overall smoothing of the daily discharge rates, and a reduction of 0.3 days in median length of stay in the post-change period (P = 0.0065). Restructuring the admission system to achieve constant daily admissions to each care team resulted in a smoothing of daily discharge rates and improved operational efficiency with shorter lengths of stay.

Impact of erythropoiesis-stimulating agent (ESA) reimbursement policy change on transfusion frequency for patients with chemotherapy-induced anemia (CIA).

e16507 Background: Two ESAs (darbepoetin alfa, epoetin alfa) are FDA-approved for reducing transfusions in patients (pts) with CIA. Clinical trial data have reported adverse safety signals in this population with ESA treatment targeting hemoglobin (Hb) > 12g/dL. In April 2007, UnitedHealthcare implemented a non-coverage policy for non-Medicare pts with Hb > 12g/dL. Previously, no Hb restrictions existed. The impact of this policy change on the proportion of ESA-treated pts with CIA requiring transfusion was evaluated. Methods: Retrospective claims of the i3 Innovus database from 7/1/2005 to 6/30/2008 were analyzed. Subjects were commercial enrollees ≥ 18 years with cancer and chemotherapy treatment, ≥ 2 ESA claims, and ≥ 1 qualifying treatment episode, which was defined as number of days from first to last ESA administration (no ESA claim for 90 days prior to first claim and 90 days after last claim). Subjects with claims for surgical procedures or dialysis were excluded. Proportion of pts transfused was evaluated comparing pts that initiated ESA treatment between 1/2006–9/2006 (prechange) and 7/2007–3/2008 (postchange). Results: 4,371 pts were identified; 2,775 and 1,709 had ≥ 1 ESA treatment episode in the pre-change and post- change periods, respectively. Age, gender, and tumor type were similar across both time periods. ESA treatment duration was longer in the prechange compared to postchange period (64.9 vs. 59.6 days; p < 0.001). In the prechange period, 11.5% of pts had ≥ 1 transfusions compared with 15.4% in postchange (p < 0.001). By subset analysis, the largest proportion of pts requiring transfusion was in those with lung cancer (19.8% pre, 29% post; p = 0.009). Conclusions: A small but significant increase in proportion of pts transfused and a small but significant decrease in ESA treatment duration was observed in the post-policy period. It is unknown if the increased transfusion rate was a result of policy implementation or the concurrent changes in the Centers for Medicare and Medicaid Services' coverage criteria for initiation of ESA therapy. Further study should evaluate the long-term impact of the policy on other clinical outcomes. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Centocor Ortho Biotech, United Healthcare Johnson & Johnson Johnson & Johnson

Evaluation of methods for estimating the effects of vegetation change and climate variability on streamflow

Changes in vegetation cover can significantly affect streamflow. Two common methods for estimating vegetation effects on streamflow are the paired catchment method and the time trend analysis technique. In this study, the performance of these methods is evaluated using data from paired catchments in Australia, New Zealand, and South Africa. Results show that these methods generally yield consistent estimates of the vegetation effect, and most of the observed streamflow changes are attributable to vegetation change. These estimates are realistic and are supported by the vegetation history. The accuracy of the estimates, however, largely depends on the length of calibration periods or pretreatment periods. For catchments with short or no pretreatment periods, we find that statistically identified prechange periods can be used as calibration periods. Because streamflow also responds to climate variability, in assessing streamflow changes it is necessary to consider the effect of climate in addition to the effect of vegetation. Here, the climate effect on streamflow was estimated using a sensitivity‐based method that calculates changes in rainfall and potential evaporation. A unifying conceptual framework, based on the assumption that climate and vegetation are the only drivers for streamflow changes, enables comparison of all three methods. It is shown that these methods provide consistent estimates of vegetation and climate effects on streamflow for the catchments considered. An advantage of the time trend analysis and sensitivity‐based methods is that they are applicable to nonpaired catchments, making them potentially useful in large catchments undergoing vegetation change.

Economic consequences of firms’ depreciation method choice: Evidence from capital investments

This study identifies several interrelated reasons why firms’ depreciation method choice is likely to influence managers’ capital investment decisions. We find that firms that use accelerated depreciation make significantly larger capital investments than firms that use straight-line depreciation. Further, we find that there has been a migration away from accelerated depreciation to straight-line depreciation over the past two decades. Firms that make such accounting changes make smaller capital investments in the post-change periods than in the pre-change periods. These results suggest that a choice made for external financial reporting purposes influences managers’ capital investment decisions.

Evaluation of Clostridium difficile-associated diarrhea with a drug formulary change in preferred fluoroquinolones.

Recent publications report that gatifloxacin might be associated with a greater incidence of Clostridium difficile-associated diarrhea (C. difficile, CDAD) than are other fluoroquinolones. We performed a drug use evaluation to examine this issue after adding gatifloxacin to the formulary and changing from levofloxacin to gatifloxacin as the preferred oral fluoroquinolone in 10 Department of Veterans Affairs (VA) medical centers in the northeastern United States. To estimate (1) the overall incidence of CDAD before and after the change from levofloxacin to gatifloxacin as the preferred oral fluoroquinolone and (2) the incidence rates for ciprofloxacin, levofloxacin, and gatifloxacin separately. Using the VA's Pharmacy Benefits Management database, the total number of days of antibiotic therapy was determined for all inpatients and outpatients of the 10 medical centers who filled at least 1 antibiotic prescription between July 1, 2003, and June 30, 2004. This time frame was chosen because it included 6 months before and 6 months after the change in the preferred oral fluoroquinolone from levofloxacin to gatifloxacin for the VA health system on January 1, 2004. For the same study period and medical centers, the electronic medical records of all inpatients and outpatients with an entry for a positive C. difficile toxin were reviewed. Positive toxins that occurred within 6 weeks of a previous positive result in the same patient were excluded. Exact Poisson tests were used to compare the incidence rates of CDAD (number of CDAD cases per 1,000 days of antibiotic treatment) for antibiotics overall, the fluoroquinolones as a group, non-fluoroquinolone antibiotics, and the individual fluoroquinolones, com-paring the 6-month time periods before (pre-change) versus after (post-change) the addition of gatifloxacin as the preferred oral fluoroquinolone. Of 505 cases of CDAD in the 12-month study period, 413 (81.7%) were associated with antibiotic use in the previous 6 weeks. Among anti-biotic users, incidence rates of CDAD were 166 per 72,114 days of antibiotic therapy in the pre-change period (2.3 cases per 1,000 days of antibiotics) versus 247 per 72,354 days in the post-change period (3.4 cases per 1,000 days of antibiotics, P < 0.001). Fluoroquinolones accounted for 54.8% of the CDAD cases in the pre-change period and 67.2% in the post-change period, representing a 22.6% relative increase in the percentage of CDAD cases that were associated with fluoroquinolone use. The CDAD incidence rates per 1,000 days of fluoroquinolone therapy were 3.7 in the pre-change period versus 7.0 in the post-change period (P < 0.001). Among fluoroqui-nolone users, gatifloxacin accounted for none of the cases of CDAD in the pre-change period when it was nonformulary and 65.1% of the cases in the post-change period, for an incidence rate of 7.6 (108 per 14,239 days). The CDAD incidence rates per 1,000 antibiotic days for patients treated with ciprofloxacin were 4.6 (24 per 5,260 days) in the pre-change period and 7.4 (40 per 5,429 days) in the post-change period, a nonsignificant trend (P = 0.079). The incidence rate of CDAD for levofloxacin increased significantly from 3.9 (75 per 19,417 days) in the pre-change period to 10.7 (44 per 4,108 days) in the post-change period (P < 0.001). The incidence rates of CDAD in the post-change period did not differ significantly for ciprofloxacin, levofloxacin, and gatifloxacin (P = 0.119). There was an increase in the incidence of CDAD among all antibiotic users and fluoroquinolone users, but not among users of non-fluoroquinolone antibiotics, in the period following the formulary change from levofloxacin to gatifloxacin as the preferred fluoroquinolone. However, rates of CDAD among the 3 fluoroquinolone antibiotics in the post-change period were not significantly different, and levofloxacin was the only fluoroquinolone that was associated with a significant increase in the rate of CDAD between the pre-change and post-change periods. These findings suggest that the increase in the CDAD incidence rate was probably not attributable to the addition of gatifloxacin to the formulary.

Effect on drug utilization and expenditures of a cost-share change from copayment to coinsurance.

While increases in prescription drug spending have moderated in recent years, drug spending is still a concern among managed care organizations and health plan administrators. In order to minimize cost increases from year to year, many health care plans have shifted more of the cost of medications to the member-consumer. Coinsurance, a benefit design in which the patient pays a percentage of the cost of the medication, is garnering more attention as a type of cost-sharing that differs from the traditional copayment model. To estimate the impact on medication expenditures and utilization of a pharmacy benefit design change from 3-tier copayment to coinsurance. Drug expenditures and utilization of beneficiaries aged >or =18 years and continuously enrolled in 2 privately insured groups were compared before and after a benefit design change in 1 of the groups. For the 12 months before the benefit design change, both groups had a 3-tier, fixed-dollar copayment structure with identical cost-sharing per 30-day supply: $10 tier-1 copayment for generic drugs, $25 tier-2 copayment for preferred brand drugs, and $40 tier-3 copayment for non-preferred brand drugs. On September 1, 2005, a 4-tier coinsurance benefit design (25% for all tiers except tier-3 [non-preferred] drugs at 50%, with minimum and maximum patient out-of-pocket [OOP] cost applied to each tier) was implemented in the intervention group (N = 46,311). The 3-tier copayment design was maintained in the comparison group (N = 7,916). A difference-in-difference analysis was used to estimate the effect of the benefit design change on expenditures and utilization, overall (for all prescription drugs), and for 3 classes of essential medications: antihypertensives, antidepressants, and statins. Analyses measured changes in outcomes from 6 months pre-change (October 1, 2004, through March 31, 2005) through 6 months post-change (October 1, 2005, through March 31, 2006). In the overall (all drug) analyses, per member per month (PMPM) outcome measures were total pharmacy claims and cost, beneficiary (patient OOP) cost, and employer (plan sponsor) cost. Analyses of the 3 essential drug classes were limited to members with at least 1 claim in the drug class in both the pre-change and post-change periods (N = 11,917, intervention group; 1,792, comparison group), and assessed per patient per month (PPPM) days supply, beneficiary cost, employer cost, and total cost. Beneficiaries in the intervention group paid 31.8% of total pharmacy benefit cost at the point of care versus 31.5% in the comparison group in the post-change period. The increases in beneficiary cost from the pre-change period to the post-change period were not significantly different for the intervention (7.5%) and comparison (3.0%) groups (P = 0.983). From the pre-change period to the post-change period, total spending per member increased $4.57 PMPM (6.3%), from $72.29 to $76.87 in the intervention group versus a $5.87 PMPM increase (9.5%), from $61.54 to $67.41, in the comparison group, a relative difference of $1.30 PMPM (P = 0.013). The increases in utilization from the pre-change period to the post-change period were not significantly different in the intervention group (2.4%) versus the comparison group (4.6%, P = 0.189). Utilization per patient in the 3 essential drug classes increased 4.1% (1.59 days PPPM) in the intervention group versus 9.0% (3.23 days PPPM) in the comparison group (P = 0.004). Total expenditures in the 3 classes for the intervention and comparison groups increased 8.2% ($5.07 PPPM) and 13.3% ($7.80 PPPM), respectively, a difference of $2.73 PPPM (P = 0.003). Beneficiary cost for all 3 drug classes increased $2.20 PPPM (9.2%) in the intervention group versus $2.12 PPPM (9.1%) in the comparison group (P = 0.032). The increases in employer cost for the 3 essential drug classes in the intervention group (7.5%, $2.86 PPPM) and comparison group (16.1%, $5.67 PPPM) did not significantly differ (P = 0.057). A pharmacy benefit design change from tiered copayment to tiered coinsurance, without a significant increase in beneficiary OOP costs, was associated with a lower rate of increase in total pharmacy benefit cost and no significant reduction in utilization. For utilizers in 3 essential drug classes, drug utilization and total spending increased in the coinsurance group but at a lower rate of increase compared with the copayment group. The coinsurance design provides another approach for controlling prescription utilization and spending for certain medication classes.

Statistical Modeling of Extreme Rainfall in Southwest Western Australia

Abstract Rainfall over southwest Western Australia (SWWA; 32°S southward and 118°E westward) has been decreasing over the past decades, putting further constraints on water resources in an already dry area. In this study, daily rainfall over five geographically dispersed and homogenized weather stations within SWWA are analyzed. A peak over threshold method from the extreme value theory is used to model daily rainfall above a given threshold. The Mann–Whitney–Pittitt (change point) test was applied to detect changes in annual, winter (May–October), and summer (November–April) maximum daily rainfall. Change points for winter extreme daily rainfall were found around 1965, based on different individual stations, with the extreme daily rainfall reduced since then. To demonstrate the degree of change in the winter extreme daily rainfall, at 1965 the data were stratified, and generalized Pareto distributions were fitted to the tails of the distributions for daily rainfall in the prechange period of 1930–65 (including 1965) and the postchange period of 1966–2001. The fitted tail distributions also allow the estimation of probabilities and return periods of the daily rainfall extreme. Results show that return periods for the winter extreme daily rainfall have increased after 1965, implying that winter daily rainfall extremes in SWWA are lower after 1965 than they were before. There has been vigorous debate as to what forces the drying trend, that is, whether it is part of multidecadal variability or whether it is driven by secular forcings, such as increasing atmospheric CO2 concentration. In this paper, statistical modeling is also used to identify possible associated changes in atmospheric circulation. It is found that there is a change point near 1965 in a dominant atmospheric circulation mode of the Antarctic Oscillation (AAO). The result offers qualified support for the argument that the AAO may contribute to the drying trend.

Dental visits to hospital emergency departments by adults receiving Medicaid: Assessing their use

Pain from toothaches represents a significant problem. People lacking access to private dental services may use hospital emergency departments, or EDs. In 1993, Maryland eliminated Medicaid reimbursement to dentists for adult emergency services. The authors used the change in Medicaid policy that eliminated dentist reimbursement to establish two study periods. Data tapes describing patients' use of EDs were obtained from the Maryland Medicaid Management Information System. A total of 3,639 people visited EDs for dental problems sometime during the four-year study period. After controlling for age, race and sex, the authors found that the rate of ED claims was 12 percent higher in the postchange period than in the prechange period. Comparisons between periods show significant rate increases during the postchange period for men, whites, African-Americans and patients aged 21 through 44 years and 45 through 64 years. The change in Medicaid policy that eliminated dentist reimbursement and participation in the program appears to have increased the use of EDs for the treatment of dental problems. Practice Implications. Many EDs lack dental services and are not capable of providing definitive treatment. When definitive treatment is not provided, this pattern of care may be repeated if patients are forced to return for treatment.

EFFECTS OF TOTAL ENVIRONMENTAL CHANGE ON MILK PRODUCTION

The effects on production of moving a herd of 27 Ayrshire milking cows from one environment to a totally different one, with changed methods of feeding, milking and housing, were studied. Following a pre-change period of 105 days, during which each cow was recorded on alternate days for yield of milk and fat, lactose and protein percentages, the immediate effects of the change, the recovery if any, and permanent changes in production were analyzed over a 19-day period. All traits were affected in mean levels, except protein percentage. Milk yield fell by 2.6 kg (13.0%), fat percentage increased by 0.43 units (10.0%), and lactose percentage fell by 0.23 units (4.8%). Protein percentage was unaltered throughout. Milk yield and lactose percentage did not change after the immediate drop. Fat percentage returned linearly from the initial increase, to expectation at 11 days after the change, and continued to decline for another 8 days. The variances of all the traits were temporarily inflated by factors of 2,5,3 and 3 for milk yield, fat percentage, protein percentage and lactose percentage, respectively. The gradual decline to normal, pre-change variance levels took 7–8 days for compositional traits and 10 days for milk yield. Estimates of these means, variances and coefficients of variation are given.