U.S. CHAIN RESTAURANT EFFICIENCY

The growth of corporate food service firms and the resulting competition places increasing pressures on available resources and their efficient usage. This analysis measures efficiencies for U. S. chain restaurants and determines associations between managerial and operational characteristics. Using a ray-homothetic production function, frontiers were estimated for large and small restaurant chains. Technical and scale efficiencies were then derived for the firms. Finally, a Tobit analysis measured associations between technical efficiencies and firm characteristics. Results showed differences based on firm size, but factors such as experience, service format, unit size, and menu were strongly associated with efficiency, perhaps offsetting some firm size effects.Agribusiness,

Diet-induced obesity impairs mammary development and lactogenesis in murine mammary gland

We have developed a mouse model of diet-induced obesity that shows numerous abnormalities relating to mammary gland function. Animals ate 40% more calories when offered a high-fat diet and gained weight at three times the rate of controls. They exhibited reduced conception rates, increased peripartum pup mortality, and impaired lactogenesis. The impairment of lactogenesis involved lipid accumulation in the secretory epithelial cells indicative of an absence of copius milk secretion. Expression of mRNAs for -casein, whey acid protein, and -lactalbumin were all decreased immediately postpartum but recovered as lactation was established over 2–3 days. Expression of acetyl-CoA carboxylase (ACC)- mRNA was also decreased at parturition as was the total enzyme activity, although there was a compensatory increase in the proportion in the active state. By day 10 of lactation, the proportion of ACC in the active state was also decreased in obese animals, indicative of suppression of de novo fatty acid synthesis resulting from the supply of preformed fatty acids in the diet. Although obese animals consumed more calories in the nonpregnant and early pregnant states, they showed a marked depression in fat intake around day 9 of pregnancy before food intake recovered in later pregnancy. Food intake increased dramatically in both lean and obese animals during lactation although total calories consumed were identical in both groups. Thus, despite access to high-energy diets, the obese animals mobilized even more adipose tissue during lactation than their lean counterparts. Obese animals also exhibited marked abnormalities in alveolar development of the mammary gland, which may partially explain the delay in differentiation evident during lactogenesis

Fire Behavior Modeling to Assess Net Benefits of Forest Treatments on Fire Hazard Mitigation and Bioenergy Production in Northeastern California

The fire behavior modeling described here, conducted as part of the Biomass to Energy (B2E) life cycle assessment, is funded by the California Energy Commission to evaluate the potential net benefits associated with treating and utilizing forest biomass. The B2E project facilitates economic, environmental, energy, and effectiveness assessments of the potential public benefits associated with: (1) various options for treatment, disposition, and utilization of forest biomass and (2) energy production from biomass produced by forest remediation activities. The study models forest conditions, fire behavior and fuel changes over a 40-year period, under three fuel treatment scenarios: no treatment; harvest and thinning on industrial private lands; and a range of prescriptions on industrial private and public multiple use ownerships. Effects of three fuel treatment scenarios are evaluated on fuel treatment effectiveness, economic feasibility, energy production supported, ecosystem impacts, and the location and capacity of modeled biomass facilities. The B2E project is novel in its scale of analysis, modeling the landscape effects of fire and treatments on 2.7 million acres of forest and brushland in the northern Sierra Nevada. This landscape represents high-hazard fuel areas, a broad range of ownerships, diverse habitats, complex infrastructure, and other values at risk. With 50 percent public multiple use and 17 percent industrial private lands, this landscape provides a unique opportunity to evaluate the effectiveness of Strategically Placed Area Treatments (SPLATs) and compare them with industrial private thinning and harvest. With average pretreatment biomass levels of 79 bone-dry tons (bdts) per acre, the private treatments removed an average of 31 bdts/acre while SPLATs removed an average of 24 bdts/acre. Wildfire modeling of these treatments showed a 6 percent reduction in the number of acres burned from private treatments and a 22 percent reduction from both private and SPLATs on public lands. While the ownerships, forest type, density, and slope dictated the type of treatment prescriptions, the spatial arrangement of treatments has a greater impact on their ability to change fire intensity and extent than the prescription applied

Bears Remain Top Summer Predators

In the ten years since wolves (Canis lupus) were restored to Yellowstone National Park (YNP), elk (Cervus elaphus) numbers have substantially decreased. The northern range elk herd is the largest elk herd in Yellowstone, and constitutes the majority of the park’s elk population. During 1994–2005, early winter counts of northern Yellowstone elk decreased from 19,045 to 9,545. Also, during winters 2000–2004, calf:cow ratios declined from 29:100 to 12:100, and were among the lowest recorded during the past several decades. Though many factors (e.g., predation, hunting, and drought) likely contributed to this decreasing abundance and low recruitment, several state and federal legislators continue to speculate that wolves are the primary reason for the recent decrease in elk recruitment rates, and have called for the immediate delisting and liberal control of the abundance and distribution of wolves. Because both wolves and elk are culturally, economically, and ecologically important in the Yellowstone area, it is vital to determine the basis for the decline in the elk population. To help this effort, we initiated a three-year study of northern Yellowstone elk calf mortality in May 2003. Our study was designed to follow up on Dr. Francis Singer et al.’s baseline pre–wolf restoration elk calf mortality study (1987–1990)

Kinematic dynamo action in a sphere. I. Effects of differential rotation and meridional circulation on solutions with axial dipole symmetry

A sphere containing electrically conducting fluid can generate a magnetic field by dynamo action, provided the flow is sufficiently complicated and vigorous. The dynamo mechanism is thought to sustain magnetic fields in planets and stars. The kinematic dynamo problem tests steady flows for magnetic instability, but rather few dynamos have been found so far because of severe numerical difficulties. Dynamo action might, therefore, be quite unusual, at least for large-scale steady flows. We address this question by testing a two-parameter class of flows for dynamo generation of magnetic fields containing an axial dipole. The class of flows includes two completely different types of known dynamos, one dominated by differential rotation (D) and one with none. We find that 36% of the flows in seven distinct zones in parameter space act as dynamos, while the remaining 64% either fail to generate this type of magnetic field or generate fields that are too small in scale to be resolved by our numerical method. The two previously known dynamo types lie in the same zone, and it is therefore possible to change the flow continuously from one to the other without losing dynamo action. Differential rotation is found to promote large-scale axisymmetric toroidal magnetic fields, while meridional circulation (M) promotes large-scale axisymmetric poloidal fields concentrated at high latitudes near the axis. Magnetic fields resembling that of the Earth are generated by D > 0, corresponding to westward flow at the surface, and M of either sign but not zero. Very few oscillatory solutions are found

Elk Calf Survival and Mortality Following Wolf Restoration to Yellowstone National Park

We conducted a 3-year study (May 2003–Apr 2006) of mortality of northern Yellowstone elk (Cervus elaphus) calves to determine the cause for the recruitment decline (i.e., 33 calves to 13 calves/100 adult F) following the restoration of wolves (Canis lupus). We captured, fit with radiotransmitters, and evaluated blood characteristics and disease antibody seroprevalence in 151 calves ≤6 days old (68M:83F). Concentrations (x, SE) of potential condition indicators were as follows: thyroxine (T4; 13.8 μg/dL, 0.43), serum urea nitrogen (SUN; 17.4 mg/dL, 0.57), γ-glutamyltransferase (GGT; 66.4 IU/L, 4.36), gamma globulins (GG; 1.5 g/dL, 0.07), and insulin-like growth factor-1 (IGF-1; 253.6 ng/mL, 9.59). Seroprevalences were as follows: brucellosis (Brucella abortus; 3%), bovine-respiratory syncytial virus (3%), bovine-viral-diarrhea virus type 1 (25%), infectious-bovine rhinotracheitis (58%), and bovine parainfluenza-3 (32%). Serum urea nitrogen, GGT, GG, and IGF-1 varied with year; T4, SUN, and GG varied with age (P ≤ 0.01); and SUN varied by capture area (P=0.02). Annual survival was 0.22 (SE=0.035, n=149) and varied by calving area but not year. Neonates captured in the Stephens Creek/Mammoth area of Yellowstone National Park, USA, had annual survival rates \u3e3x higher (0.54) than those captured in the Lamar Valley area (0.17), likely due to the higher predator density in Lamar Valley. Summer survival (20 weeks after radiotagging) was 0.29 (SE=0.05, n=116), and calving area, absolute deviation from median birth date, and GG were important predictors of summer survival. Survival during winter (Nov–Apr) was 0.90 (SE=0.05, n=42), and it did not vary by calving area or year. Sixty-nine percent (n=104) of calves died within the first year of life, 24% (n=36) survived their first year, and 7% (n=11) had unknown fates. Grizzly bears (Ursus arctos) and black bears (Ursus americanus) accounted for 58–60% (n = 60–62) of deaths, and wolves accounted for 14–17% (n = 15–18). Summer predation (95% of summer deaths) increased, and winter malnutrition (0% of winter deaths) decreased, compared with a similar study during 1987–1990 (72% and 58%, respectively). Physiological factors (e.g., low levels of GG) may predispose calves to predation. Also, the increase in bear numbers since wolf restoration and spatial components finer than the northern range should be considered when trying to determine the causes of the northern Yellowstone elk decline. This is the first study to document the predation impacts from reintroduced wolves on elk calf mortality in an ecosystem already containing established populations of 4 other major predators (i.e., grizzly and black bears, cougars [Puma concolor], and coyotes [Canis latrans]). The results are relevant to resource managers of the Yellowstone ecosystem in understanding the dynamics of the elk population, in providing harvest quota recommendations for local elk hunts to the Montana Department of Fish, Wildlife and Parks, the United States Fish and Wildlife Service regarding wolf and grizzly bear recovery, and to all areas worldwide where predators are increasing, by providing managers with information about potential carnivore impacts on elk populations

Gray Wolf (\u3ci\u3eCanis lupus\u3c/i\u3e) Death by Stick Impalement

Although Canis lupus L. (Gray Wolf) individuals are sometimes impaled by sticks, we could find no documentation of natural impalement by sticks as a cause of death for wild Wolves. Here we report on a wild Gray Wolf from northeastern Minnesota that died due to stick puncture of its thorax and abdomen

On-line learning in radial basis functions networks

An analytic investigation of the average case learning and generalization properties of Radial Basis Function Networks (RBFs) is presented, utilising on-line gradient descent as the learning rule. The analytic method employed allows both the calculation of generalization error and the examination of the internal dynamics of the network. The generalization error and internal dynamics are then used to examine the role of the learning rate and the specialization of the hidden units, which gives insight into decreasing the time required for training. The realizable and over-realizable cases are studied in detail; the phase of learning in which the hidden units are unspecialized (symmetric phase) and the phase in which asymptotic convergence occurs are analyzed, and their typical properties found. Finally, simulations are performed which strongly confirm the analytic results

Remote Estimates of Ice Algae Biomass and Their Response to Environmental Conditions during Spring Melt

In this study, we support previous work showing that a normalized difference index (NDI) using two spectral bands of transmitted irradiance (478 and 490 nm) can be used as a non-invasive method to estimate sea ice chlorophyll a (chl a) following a simple calibration to the local region. Application of this method during the spring bloom period (9 May to 26 June) provided the first non-invasive time series dataset used to monitor changes in bottom ice chl a concentration, an index of algal biomass, at a single point location. The transmitted irradiance dataset was collected on landfast first-year sea ice of Allen Bay, Nunavut, in 2011, along with the physical variables thought to affect chl a accumulation and loss at the ice bottom. Time series biomass calculated using the NDI technique adhered well to core based biomass estimates although, chl a values remained low throughout the bloom, reaching a maximum of 27.6 mg m-2 at the end of May. It is likely that warming of the bottom ice contributed to loss of chl a through its positive influence on brine drainage and ice melt. Chl a content in the bottom ice was also significantly affected by a storm event on 10 June, which caused extensive surface melt and a rapid increase in the magnitude of transmitted irradiance. Furthermore, the velocity of current, measured below the ice at the end of a spring neap-tidal cycle, was negatively associated with ice algae chl a biomass (the stronger the current, the less biomass). The NDI method to remotely estimate ice algal biomass proved useful for application in our time series process study, providing a way to assess the effects of changes to the sea ice environment on the biomass of a single population of ice algae.La présente étude vient appuyer d’anciennes études selon lesquelles un indice par différence normalisée (IDN) recourant à deux bandes spectrales d’éclairement énergétique transmis (478 et 490 nm) peut servir de méthode non invasive d’estimation de la chlorophylle a (chl a) de glace de mer suivant un simple étalonnage dans une aire locale. Le recours à cette méthode pendant la saison de l’efflorescence printanière (du 9 mai au 26 juin) a permis d’obtenir le premier ensemble de données non invasives en séries chronologiques dans le but de surveiller les changements se manifestant dans la concentration de chl a de la glace de fond, un indice de biomasse algale, en un seul point. Les données relatives à l’éclairement énergétique transmis ont été recueillies à partir de la glace de mer de rive de l’année à la baie Allen, au Nunavut, en 2011, en même temps que les variables physiques censées avoir des effets sur l’accumulation de chl a et sur la perte de glace de fond. Les données chronologiques relatives à la biomasse calculées à l’aide de la technique de l’IDN cadraient bien avec les estimations de la biomasse obtenues à l’aide d’échantillons, bien que les valeurs de la chl a restaient à la baisse pendant l’efflorescence, pour atteindre un maximum de 27,6 mg m-2 à la fin du mois de mai. Il est vraisemblable que le réchauffement de la glace de fond a entraîné la perte de chl a en raison de son influence positive sur l’égouttage de la saumure et la fonte des glaces. La teneur en chl a de la glace de fond a également été fortement touchée par un événement pluvio-hydrologique qui a eu lieu le 10 juin, événement qui a entraîné une importante fonte en surface et l’augmentation rapide de la magnitude de l’éclairement énergétique transmis. Par ailleurs, la vélocité du courant, mesurée sous la glace à la fin d’un cycle printanier de marée de mortes-eaux, a été négativement liée à la biomasse en chl a de l’algue glaciaire (plus le courant était fort, moins la biomasse était grande). La méthode de l’IDN en vue d’estimer la biomasse de l’algue glaciaire à distance s’est avérée utile dans le cadre de l’application de notre étude en séries chronologiques, car elle a présenté un moyen d’évaluer les effets des changements caractérisant l’environnement de la glace de mer sur la biomasse d’une seule population d’algues glaciaires