Bleaching and diffusion dynamics in optofluidic dye lasers

We have investigated the bleaching dynamics that occur in optofluidic dye lasers where the liquid laser dye in a microfluidic channel is locally bleached due to optical pumping. We find that for microfluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone. By relying on diffusion rather than convection to generate the necessary dye replenishment, our observation potentially allows for a significant simplification of optofluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip microfluidic pumping devices.Comment: 3 pages including 3 figures. Accepted for AP

Frequency Of Development Of Connective Tissue Disease In Statin-Users Versus Nonusers

Statins have pleiotropic properties that may affect the development of connective tissue diseases (CTD). The objective of this study was to compare the risk of CTD diagnoses in statin users and nonusers. This study was a propensity score-matched analysis of adult patients (30 to 85 years old) in the San Antonio military medical community. The study was divided into baseline (October 1, 2003 to September 30, 2005), and follow-up (October 1, 2005 to March 5, 2010) periods. Statin users received a statin prescription during fiscal year 2005. Nonusers did not receive a statin at any time during the study. The outcome measure was the occurrence of 3 diagnosis codes of the International Classification of Diseases, 9th Revision, Clinical Modification consistent with CTD. We described co-morbidities during the baseline period using the Charlson Comorbidity Index. We created a propensity score based on 41 variables. We then matched statin users and nonusers 1:1, using a caliper of 0.001. Of 46,488 patients who met study criteria (13,640 statin users and 32,848 nonusers), we matched 6,956 pairs of statin users and nonusers. Matched groups were similar in terms of patient age, gender, incidence of co-morbidities, total Charlson Comorbidity Index, health care use, and medication use. The odds ratio for CTD was lower in statin users than nonusers (odds ratio: 0.80; 95% confidence interval: 0.64 to 0.99; p = 0.05). Secondary analysis and sensitivity analysis confirmed these results. In conclusion, statin use was associated with a lower risk of CTD. Published by Elsevier Inc.Pharmac

Economic Effects of the 1988 Drought in North Dakota: A 1989 Update of the Financial Conditions of Farm and Ranch Operators

Agricultural Finance, Farm Management, Resource /Energy Economics and Policy,

Outlook of North Dakota Farm Households: Results of the 1988 Longitudinal Farm Survey

Agricultural Finance, Farm Management,

Reexamination of Hagen-Poiseuille flow: shape-dependence of the hydraulic resistance in microchannels

We consider pressure-driven, steady state Poiseuille flow in straight channels with various cross-sectional shapes: elliptic, rectangular, triangular, and harmonic-perturbed circles. A given shape is characterized by its perimeter P and area A which are combined into the dimensionless compactness number C = P^2/A, while the hydraulic resistance is characterized by the well-known dimensionless geometrical correction factor alpha. We find that alpha depends linearly on C, which points out C as a single dimensionless measure characterizing flow properties as well as the strength and effectiveness of surface-related phenomena central to lab-on-a-chip applications. This measure also provides a simple way to evaluate the hydraulic resistance for the various shapes.Comment: 4 pages including 3 figures. Revised title, as publishe

Economic Impact of the Conservation Reserve Program in North Dakota

Environmental Economics and Policy, Land Economics/Use,

Iowa Swiss-type cheese

New types of cheese for Iowa have been receiving the attention of the Iowa Agricultural Experiment Station for a number of years. A previous publication (1) described the method of manufacture which has been used in the production of many thousands of pounds of Iowa Blue Cheese. This publication deals with the process used in the Iowa State College laboratories in manufacturing a Swiss-type cheese. In the course of these experiments a total of 25,136 lbs. of the cheese has been manufactured and marketed, utilizing approximately a quarter of a million pounds of milk

Iowa blue cheese

Iowa is an importer of cheese. In 1933 Iowa dairy plants manufactured 1,491,822 pounds of cheese.2 In the same year consumption is estimated to have been 10,254,397 pounds, using the 1933 United States Department of Agriculture figure of 4.15 pounds per capita and 1930 Iowa census figures as a basis of computation. In 1933 Iowa dairy plants produced 14.6 percent of the cheese consumed in the state. If this percentage could be greatly increased it would result in a larger and more diversified market for Iowa milk. Production of cured cheese in Iowa has up to the present consisted almost entirely of the staple variety known as Cheddar or American cheese. Small production has not been the result either of lack of milk or of inability to produce an acceptable cheese. Rather it has been the inability of the average dairy plant to pay enough more for milk to be used for cheesemaking to divert the milk from other manufacturing uses, principally butter. The high value placed by the Iowa farmer upon skimmilk for feeding purposes when used as a supplement to corn in hog production has undoubtedly been one important factor in limiting the production of cheese. When milk is made into cheese the skimmilk is not available for feeding on the farm. Instead, whey, which is estimated to possess half the value of skimmilk, is available for the feeding operations. This and other factors require that the dairy plants must be able to pay a substantially higher price for milk fat for cheesemaking than for buttermaking if milk is to be available for the former. Expansion of cheese production in Iowa apparently depends upon some method of increasing the returns which can be obtained from cheese so that a relatively larger payment can be made to the milk producer

Strong plasmon-phonon splitting and hybridization in 2D materials revealed through a self-energy approach

We reveal new aspects of the interaction between plasmons and phonons in 2D materials that go beyond a mere shift and increase in plasmon width due to coupling to either intrinsic vibrational modes of the material or phonons in a supporting substrate. More precisely, we predict strong plasmon splitting due to this coupling, resulting in a characteristic avoided crossing scheme. We base our results on a computationally efficient approach consisting in including many-body interactions through the electron self-energy. We specify this formalism for a description of plasmons based upon a tight-binding electron Hamiltonian combined with the random-phase approximation. This approach is accurate provided vertex corrections can be neglected, as is is the case in conventional plasmon-supporting metals and Dirac-fermion systems. We illustrate our method by evaluating plasmonic spectra of doped graphene nanotriangles with varied size, where we predict remarkable peak splittings and other radical modifications in the spectra due to plasmons interactions with intrinsic optical phonons. Our method is equally applicable to other 2D materials and provides a simple approach for investigating coupling of plasmons to phonons, excitons, and other excitations in hybrid thin nanostructures

Transport coefficients for electrolytes in arbitrarily shaped nano and micro-fluidic channels

We consider laminar flow of incompressible electrolytes in long, straight channels driven by pressure and electro-osmosis. We use a Hilbert space eigenfunction expansion to address the general problem of an arbitrary cross section and obtain general results in linear-response theory for the hydraulic and electrical transport coefficients which satisfy Onsager relations. In the limit of non-overlapping Debye layers the transport coefficients are simply expressed in terms of parameters of the electrolyte as well as the geometrical correction factor for the Hagen-Poiseuille part of the problem. In particular, we consider the limits of thin non-overlapping as well as strongly overlapping Debye layers, respectively, and calculate the corrections to the hydraulic resistance due to electro-hydrodynamic interactions.Comment: 13 pages including 4 figures and 1 table. Typos corrected. Accepted for NJ