A clarification of the Goodwin model of the growth cycle

We show that there is a difficulty in the original Goodwin model which isalso found in some more recent applications. In it both the labour share and theproportion employed can exceed unity, properties which are untenable. However, weshow that the underlying dynamic structure of the model can be reformulated toensure that these variables cannot exceed unity. An illustrative example extends theoriginal model, and we argue it is both plausible and satisfies the necessary unit boxrestrictions. We show that there is a difficulty in the original Goodwin model which isalso found in some more recent applications. In it both the labour share and theproportion employed can exceed unity, properties which are untenable. However, weshow that the underlying dynamic structure of the model can be reformulated toensure that these variables cannot exceed unity. An illustrative example extends theoriginal model, and we argue it is both plausible and satisfies the necessary unit boxrestrictions

A bright, pulsed two-mode squeezer

We report the realization of a bright ultrafast two-mode squeezer based on type II parametric downconversion (PDC) in periodically poled $\mathrm{KTiOPO_4}$ (PP-KTP) waveguides. It produces a pulsed two-mode squeezed vacuum state: a photon-number entangled pair of truly single-mode pulses or, in terms of continuous variables quantum optics, a pulsed, single mode Einstein-Podolsky-Rosen (EPR) state in the telecom regime. We prove the single mode character of our source by measuring its $g^{(2)}$ correlation function and demonstrate a mean photon number of up to 2.5 per pulse, equivalent to 11dB of two-mode squeezing.Comment: 4 pages, 3 figure

A Preliminary Evaluation of the Missouri Family Development Training and Credentialing Program (MOFDC)

In this brief, we present preliminary findings from a quantitative evaluation of the Missouri Family Development Training and Credentialing Program (MO FDC). The MO FDC is designed to reorient human service practice to the family support approach. It is part of a growing nationwide movement whose goal is to empower both workers and families, and which recognizes the need for credentialing or certification of direct human service providers (Dean, 1998; Sexton, Lobman, Constans, Snyder, & Ernest 1997). Based on a curriculum developed at Cornell University, Empowerment Skills for Family Workers, 2nd Edition (Forest, 2003), it is in place in 14 other states including: Alabama, Alaska, Arizona, California, Connecticut, Florida, Georgia, Maine, Massachusetts, New York, New Jersey, North Carolina, Rhode Island, and Washington. The FDC is increasingly regarded nationwide as the most comprehensive credentialing program for family support workers.Includes bibliographical reference

Heralded Generation of Ultrafast Single Photons in Pure Quantum States

We present an experimental demonstration of heralded single photons prepared in pure quantum states from a parametric downconversion source. It is shown that, through controlling the modal structure of the photon pair emission, one can generate pairs in factorable states and thence eliminate the need for spectral filters in multiple-source interference schemes. Indistinguishable heralded photons were generated in two independent spectrally engineered sources, and, by performing a Hong-Ou-Mandel interference between them without spectral filters at a raw visibility of 94.4%, their purity was measured to be over 95%.Comment: 5 pages, 4 figure

Targeted Cattle Grazing to Enhance Sage-Grouse Brood-Rearing Habitat

Often, greater sage-grouse (Centrocercus urophasianus) brood-rearing habitats dominated by dense mountain big sagebrush (Artemisia tridentata vaseyana; >10-25% canopy cover) limit important forbs and arthropods sage-grouse rely on during summer. We investigated whether protein supplementation could concentrate cattle during fall to reduce sagebrush canopy cover and increase the diversity and abundance of forbs and arthropods. We applied targeted cattle grazing within three large, contiguous pastures in the Beaverhead Mountains of southwestern Montana. In each pasture, we selected one 4-ha macroplot of dense sagebrush (>30%). Within each macroplot, we placed low-moisture block protein supplement in four microsites (78.5-m2) and compared cattle response to four untreated control microsites. The following summer we measured herbaceous canopy cover and composition, shrub canopy cover, ground cover, forb and arthropod diversity, and arthropod density for each treated and untreated microsites. Mountain big sagebrush canopy cover was 71% less in treated vs. untreated microsites (11% vs. 38% canopy cover, respectively; P <0.001). Bite count observations indicated that sagebrush cover was reduced by cattle trampling rather than browsing, as sagebrush comprised <1% of cattle diets. Forb diversity was 13% greater in treated microsites (P = 0.094), forb species richness was 16% greater in treated microsites (P = 0.044), and forb composition trended higher in treated microsites (45% of herbaceous composition in treated microsites vs. 32% in untreated microsites; P = 0.106). Lepidoptera density trended 18% greater in treated microsites (P = .133). Our results indicate that protein supplementation during late fall can concentrate cattle to enhance sage-grouse brood-rearing habitat

Spontaneous parametric down-conversion in asymmetric couplers: Photon purity enhancement and intrinsic spectral filtering

We analyze the process of photon-pair generation via spontaneous parametric down-conversion in a quadratic nonlinear asymmetric waveguide coupler. The two waveguides have different geometry, such that light coupling only occurs within a narrow bandwidth of one of the generated (signal) photon modes, while the other (idler) photon together with the pump stay localized in one (driven) arm of the coupler. We demonstrate that such a setup represents a powerful and flexible tool for engineering spectral properties of generated photon pairs. Mode hybridization and dispersion of coupling can be utilized for shifting the balance between group velocities of interacting pump, signal, and idler fields, subsequently leading to a significant increase of spectral factorizability (purity) of photons. We also show that for interaction lengths shorter than one beat length, generated pairs with signal photon being localized in the auxiliary (not pumped) arm of the coupler appear to be spectrally localized in both signal and idler components. The bandwidth of such intrinsic filtering of generated photons can be controlled by several geometrical parameters

Effect of Varying Levels of Fatty Acids from Palm Oil on Feed Intake and Milk Production in Holstein Cows

To determine the optimum feeding level of fatty acids of palm oil (PALM; Energizer RP10; 86.6% palmitic acid) on milk production, lactating cows (n = 18) were randomly assigned to a treatment sequence in replicated 4 x 4 Latin squares. Animals were assigned to squares by parity (3 multiparous and 1 primiparous squares with primiparous in the incomplete square). The 4 diets were designed to provide 0, 500, 1,000, and 1,500 g of PALM per day. Cows were fed individually with feed intake measured daily. Each period lasted 16 d with milk production and composition determined the final 2 d. Milk production, milk composition and feed intake data were analyzed using the MIXED procedure of SAS. Milk yields were 30.9, 34.0, 34.2, and 34.2 kg/ d (SEM = 1.9) for the 0, 500, 1,000, and 1,500 g levels, respectively. Milk yield was increased by the addition of PALM; however, there were no differences among the levels of PALM. Milk fat percentage was also increased from 3.44% for 0 g to 3.95% (SEM = 0.17) across all levels of PALM but there were no differences among the PALM treatments. Dry matter intakes were 23.3, 26.4, 24.7, and 23.8 kg/d (SEM = 1.4) for the 0, 500, 1,000 and 1,500 g levels, respectively. The addition of PALM increased milk yield and milk fat percentage, and no adverse effects on dry matter intake were observed

Accessing the purity of a single photon by the width of the Hong-Ou-Mandel interference

We demonstrate a method to determine the spectral purity of single photons. The technique is based on the Hong-Ou-Mandel (HOM) interference between a single photon state and a suitably prepared coherent field. We show that the temporal width of the HOM dip is not only related to reciprocal of the spectral width but also to the underlying quantum coherence. Therefore, by measuring the width of both the HOM dip and the spectrum one can directly quantify the degree of spectral purity. The distinct advantage of our proposal is that it obviates the need for perfect mode matching, since it does not rely on the visibility of the interference. Our method is particularly useful for characterizing the purity of heralded single photon states.Comment: Extended version, 16 pages, 9 figure