A comparison of recharge rates in aquifers of the United States based on groundwater-age data

Shallow aquifers are prone to nitrate contamination worldwide. In western Nebraska, high groundwater nitrate concentrations ([NO3−]) have resulted in the exploration of new groundwater and nitrogen management regulations in the North Platte Natural Resources District (NPNRD). A small region of NPNRD (“Dutch Flats”) was the focus of intensive groundwater sampling by the United States Geological Survey from 1995 to 1999. Nearly two decades later, notable shifts have occurred in variables related to groundwater recharge and [NO3−], including irrigation methods. The objective of this study was to evaluate how changes in these variables, in part due to regulatory changes, have impacted nitrate-contaminated groundwater in the Dutch Flats area. Groundwater samples were collected to assess changes in: (1) recharge rates; (2) biogeochemical processes; and (3) [NO3−]. Groundwater age increased in 63% of wells and estimated recharge rates were lower for 88% of wells sampled (n = 8). However, mean age and recharge rate estimated in 2016 (19.3 years; R = 0.35 m/year) did not differ significantly from mean values determined in 1998 (15.6 years; R = 0.50 m/year). δ15N-NO3− (n = 14) and dissolved oxygen data indicate no major changes in biogeochemical processes. Available long-term data suggest a downward trend in normalized [NO3−] from 1998 to 2016, and lower [NO3−] was observed in 60% of wells sampled in both years (n = 87), but median values were not significantly different. Collectively, results suggest the groundwater system is responding to environmental variables to a degree that is detectable (e.g., trends in [NO3−]), although more time and/or substantial changes may be required before it is possible to detect significantly different mean recharge.

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Party Strength in the United States: Some Corrections

The Journal of Politics ◽

10.1017/s0022381600041591 ◽

1975 ◽

Vol 37 (2) ◽

pp. 641-642 ◽

Cited By ~ 1

Author(s):

Paul T. David

Keyword(s):

United States ◽

The United States ◽

Party Strength

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Correlative microscopy in distrubuted (client/server) computing environments: tools for catalyzing the rapid dissemination of information about the cell biology of the human prostate

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100139780 ◽

1995 ◽

Vol 53 ◽

pp. 682-683

Author(s):

A. Hakam ◽

J.T. Gau ◽

M.L. Grove ◽

B.A. Evans ◽

M. Shuman ◽

...

Keyword(s):

United States ◽

Cell Biology ◽

Tissue Bank ◽

The United States ◽

Prostate Adenocarcinoma ◽

Correlative Microscopy ◽

Client Server ◽

Critical Elements ◽

Transplant Organ

Prostate adenocarcinoma is the most common malignant tumor of men in the United States and is the third leading cause of death in men. Despite attempts at early detection, there will be 244,000 new cases and 44,000 deaths from the disease in the United States in 1995. Therapeutic progress against this disease is hindered by an incomplete understanding of prostate epithelial cell biology, the availability of human tissues for in vitro experimentation, slow dissemination of information between prostate cancer research teams and the increasing pressure to “ stretch” research dollars at the same time staff reductions are occurring.To meet these challenges, we have used the correlative microscopy (CM) and client/server (C/S) computing to increase productivity while decreasing costs. Critical elements of our program are as follows:1) Establishing the Western Pennsylvania Genitourinary (GU) Tissue Bank which includes >100 prostates from patients with prostate adenocarcinoma as well as >20 normal prostates from transplant organ donors.

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Digital image acquisition, processing, and analysis in a polymer microscopy laboratory

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100170001 ◽

1994 ◽

Vol 52 ◽

pp. 454-455

Author(s):

Vinod K. Berry ◽

Xiao Zhang

Keyword(s):

United States ◽

Image Analysis ◽

Digital Image ◽

Image Acquisition ◽

Image Transmission ◽

The United States ◽

Quantitative Image Analysis ◽

Quantitative Image

In recent years it became apparent that we needed to improve productivity and efficiency in the Microscopy Laboratories in GE Plastics. It was realized that digital image acquisition, archiving, processing, analysis, and transmission over a network would be the best way to achieve this goal. Also, the capabilities of quantitative image analysis, image transmission etc. available with this approach would help us to increase our efficiency. Although the advantages of digital image acquisition, processing, archiving, etc. have been described and are being practiced in many SEM, laboratories, they have not been generally applied in microscopy laboratories (TEM, Optical, SEM and others) and impact on increased productivity has not been yet exploited as well.In order to attain our objective we have acquired a SEMICAPS imaging workstation for each of the GE Plastic sites in the United States. We have integrated the workstation with the microscopes and their peripherals as shown in Figure 1.

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Silence of the Land: On the Historical Irrelevance of Territory to Congressional Districting and Political Representation in the United States

Studies in American Political Development ◽

10.1017/s0898588x01010045 ◽

2001 ◽

Vol 15 (01) ◽

pp. 53-87 ◽

Cited By ~ 2

Author(s):

Andrew Rehfeld

Keyword(s):

United States ◽

House Of Representatives ◽

Political Representation ◽

The United States ◽

Representative Government ◽

Congressional District ◽

Congressional Districts ◽

Communities Of Interest

Every ten years, the United States “constructs” itself politically. On a decennial basis, U.S. Congressional districts are quite literally drawn, physically constructing political representation in the House of Representatives on the basis of where one lives. Why does the United States do it this way? What justifies domicile as the sole criteria of constituency construction? These are the questions raised in this article. Contrary to many contemporary understandings of representation at the founding, I argue that there were no principled reasons for using domicile as the method of organizing for political representation. Even in 1787, the Congressional district was expected to be far too large to map onto existing communities of interest. Instead, territory should be understood as forming a habit of mind for the founders, even while it was necessary to achieve other democratic aims of representative government.

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