Renal handling of beta-2-microglobulin in the human neonate

Renal handling of beta-2-microglobulin in the human neonate. Glomerulotubular balance for beta-2-microglobulin (β2M) in the human kidney has been reported to occur after 34 weeks conceptional age (CA), and fractional tubular reabsorption of β2M (Tβ2M) has been suggested as a useful index of renal tubular maturation. To confirm and extend these observations to include still less mature infants, renal handling of β2M was investigated during timed-urine collections with corresponding blood samples obtained from 57 infants with CA of 26 to 43 weeks and postnatal ages (PNA) 0.2 to 12 days (study 1); 18 infants were studied a second time 5 to 17 days later (study 2). GFR was measured by endogenous creatinine clearance (CCr). Tβ2M and fractional reabsorption of sodium (TNa) were calculated. Results indicated that while both increased with CA, Tβ2M (r = -0.69, P < 0.0001) and TNa (r = -0.79, P < 0.0001) varied inversely with fractional urine flow rate (V/CCr). Moreover, an inverse relationship between changes in Tβ2M and V/Ccr was observed in the same infant between study 1 and study 2 (r = -0.47, P < 0.05). These data suggest that the renal handling of β2M in the human neonate is influenced by physiologic variables that are independent of CA, and thus Tβ2M may not be a reliable predictor of renal tubular maturation in the human neonate.Elimination rénale de la béta-2-microglobuline chez le nouveau-né humain. Il a été rapporté que la balance glomérulo-tubulaire pour la béta-2-microglobuline (β2M) dans le rein humain apparait au bout de 34 semaines d'âge conceptionnel (CA), et il a été suggéré que la réabsorption tubulaire fractionnelle de la β2M (Tβ2M) est un index utile de maturation tubulaire rénale. Afin de confirmer et d'étendre ces observations en incluant des nouveau-nés encore moins matures, l'élimination rénale de β2M a été étudiée pendant des recueils d'urines minutés, avec les échantillons sanguins correspondants chez 57 nouveau-nés avec un CA de 26 à 43 semaines et des âges postnataux (PNA) de 0.2 à 12 jours (étude 1); 18 nouveau-nés ont été étudiés dans un second temps, 5 à 17 jours plus tard (étude 2). Le débit de filtration glomérulaire a été mesuré par la clearance de la créatinine endogène (CCr). Tβ2M et la réabsorption fractionnelle du sodium (TNa) ont été calculées. Les résultats ont montré que tout en augmentant avec CA, Tβ2M (r = -0.69, P < 0.0001) et TNa (r = -0.79, P < 0.0001) variaient inversement avec le débit fractionnel urinaire (V/CCr). En outre, une relation inverse entre les modifications de Tβ2M et les modifications de V/CCr a été observée chez le même nouveau-né entre l'étude 1 et l'étude 2 (r = -0.47, P < 0.05). Ces données suggèrent que l'élimination rénale de la β2M chez le nouveau-né humain est influencée par des variables physiologiques qui sont indépendantes de CA, et donc Tβ2M pourrait ne pas être un index prédictif fiable de la maturation tubulaire rénale chez le nouveau-né humain

Low-energy electron transport with the method of discrete ordinates

The one-dimensional discrete ordinates code ANISN was adapted to transport low energy (a few MeV) electrons. Calculated results obtained with ANISN were compared with experimental data for transmitted electron energy and angular distribution data for electrons normally incident on aluminum slabs of various thicknesses. The calculated and experimental results are in good agreement for a thin slab (0.2 of the electron range), but not for the thicker slabs (0.6 of the electron range). Calculated results obtained with ANISN were also compared with results obtained using Monte Carlo methods

Response of selected plant and insect species to simulated solid rocket exhaust mixtures and to exhaust components from solid rocket fuels

The effects of solid rocket fuel (SRF) exhaust on selected plant and and insect species in the Merritt Island, Florida area was investigated in order to determine if the exhaust clouds generated by shuttle launches would adversely affect the native, plants of the Merritt Island Wildlife Refuge, the citrus production, or the beekeeping industry of the island. Conditions were simulated in greenhouse exposure chambers and field chambers constructed to model the ideal continuous stirred tank reactor. A plant exposure system was developed for dispensing and monitoring the two major chemicals in SRF exhaust, HCl and Al203, and for dispensing and monitoring SRF exhaust (controlled fuel burns). Plants native to Merritt Island, Florida were grown and used as test species. Dose-response relationships were determined for short term exposure of selected plant species to HCl, Al203, and mixtures of the two to SRF exhaust

Ungulate preference for burned patches reveals strength of fire–grazing interaction

The interactions between fire and grazing are widespread throughout fire-dependent landscapes. The utilization of burned areas by grazing animals establishes the fire–grazing interaction, but the preference for recently burned areas relative to other influences (water, topography, etc.) is unknown. In this study, we determine the strength of the fire–grazing interaction by quantifying the influence of fire on ungulate site selection. We compare the preference for recently burned patches relative to the influence of other environmental factors that contribute to site selection; compare that preference between native and introduced ungulates; test relationships between area burned and herbivore preference; and determine forage quality and quantity as mechanisms of site selection. We used two large ungulate species at two grassland locations within the southern Great Plains, USA. At each location, spatially distinct patches were burned within larger areas through time, allowing animals to select among burned and unburned areas. Using fine scale ungulate location data, we estimated resource selection functions to examine environmental factors in site selection. Ungulates preferred recently burned areas and avoided areas with greater time since fire, regardless of the size of landscape, herbivore species, or proportion of area burned. Forage quality was inversely related to time since fire, while forage quantity was positively related. We show that fire is an important component of large ungulate behavior with a strong influence on site selection that drives the fire–grazing interaction. This interaction is an ecosystem process that supersedes fire and grazing as separate factors, shaping grassland landscapes. Inclusion of the fire–grazing interaction into ecological studies and conservation practices of fire-prone systems will aid in better understanding and managing these systems

Lorentzian spin foam amplitudes: graphical calculus and asymptotics

The amplitude for the 4-simplex in a spin foam model for quantum gravity is defined using a graphical calculus for the unitary representations of the Lorentz group. The asymptotics of this amplitude are studied in the limit when the representation parameters are large, for various cases of boundary data. It is shown that for boundary data corresponding to a Lorentzian simplex, the asymptotic formula has two terms, with phase plus or minus the Lorentzian signature Regge action for the 4-simplex geometry, multiplied by an Immirzi parameter. Other cases of boundary data are also considered, including a surprising contribution from Euclidean signature metrics.Comment: 30 pages. v2: references now appear. v3: presentation greatly improved (particularly diagrammatic calculus). Definition of "Regge state" now the same as in previous work; signs change in final formula as a result. v4: two references adde

Effect of stall base type on herd health, costs, and producer satisfaction

The objective of this field study was to compare effect of stall base on herd health, stall maintenance, bedding cost, and producer satisfaction. Ninety-one dairies visited during a 4-mo period starting October 14, 2005 included 33 rubber-filled mattress (RFM), 27 sand, and 31 waterbed (WB) dairies. In this study, percent culled was higher for RFM (P = 0.001) and sand (P = 0.06) than WB stall base dairies. Percent of cows in fourth lactation or greater was higher on WB than either RFM (P = 0.01) or sand (P = 0.02) dairies. There was no difference between base types for production or somatic cell count. Bedding cost per bed per week was WB ($0.73), RFM ($0.89), and sand ($0.97). Sand beds were bedded less frequently (P = 0.01). Comparisons between RFM and sand indicate higher satisfaction for RFM regarding manure management (P \u3c 0.0001) and higher satisfaction with sand for cow comfort (P \u3c 0.0001). Producers with WB were more satisfied with base life (P \u3c 0.000 1) and cow comfort (P \u3c 0.000 1) than those with RFM. Producers with WB were more satisfied with cow longevity (P \u3c 0.0001) as compared to RFM. Length of sand stall was correlated with longevity (0.56, P = 0.01) while percent of mature cows was greater on dairies that provided WBs (P = 0.02). This data indicates that WB may be a viable option for cows and producers, when good quality sand is unavailable or handling sand-laden manure is not feasible

Effect of stall base type on herd health, costs, and producer satisfaction

The objective of this field study was to compare effect of stall base on herd health, stall maintenance, bedding cost, and producer satisfaction. Ninety-one dairies visited during a 4-mo period starting October 14, 2005 included 33 rubber-filled mattress (RFM), 27 sand, and 31 waterbed (WB) dairies. In this study, percent culled was higher for RFM (P = 0.001) and sand (P = 0.06) than WB stall base dairies. Percent of cows in fourth lactation or greater was higher on WB than either RFM (P = 0.01) or sand (P = 0.02) dairies. There was no difference between base types for production or somatic cell count. Bedding cost per bed per week was WB ($0.73), RFM ($0.89), and sand ($0.97). Sand beds were bedded less frequently (P = 0.01). Comparisons between RFM and sand indicate higher satisfaction for RFM regarding manure management (P \u3c 0.0001) and higher satisfaction with sand for cow comfort (P \u3c 0.0001). Producers with WB were more satisfied with base life (P \u3c 0.000 1) and cow comfort (P \u3c 0.000 1) than those with RFM. Producers with WB were more satisfied with cow longevity (P \u3c 0.0001) as compared to RFM. Length of sand stall was correlated with longevity (0.56, P = 0.01) while percent of mature cows was greater on dairies that provided WBs (P = 0.02). This data indicates that WB may be a viable option for cows and producers, when good quality sand is unavailable or handling sand-laden manure is not feasible

Influence of Free-Stall Base on Tarsal Joint Lesions and Hygiene in Dairy Cows

The objective was to quantify the incidence of tarsal lesions and level of hygiene by stall bed type. Cows were scored on 100 dairies from Wisconsin, Minnesota, Indiana, Iowa, and New York in the fall and winter. Thirty-eight dairies used rubber-filled mattresses (RFM), 27 had sand beds, 29 had waterbeds, and 6 used compost packs (CPk). Stocking density, stall dimensions, bedding amount, bedding frequency, and type of bedding were recorded. One pen of early-lactation multiparous cows on each dairy was scored based on injury of the tarsal joints at the lateral and medial surfaces and tuber calcis at the dorsal, lateral, and medial surfaces. A tarsal score of 1 represented hair loss, 2 was moderate, and 3 indicated severe swelling. Differences between bed types in the percentages of cows with lesions were tested with one-way ANOVA by lesion severity and incidence, with farm as the experimental unit. Cows on sand beds or waterbeds had fewer lesion scores of 1, 2, and 3 than those on RFM. The percentages of score 1 were 54.6 ± 4.4 (RFM), 22.5 ± 4.7 (sand), and 29.8 ± 4.3 (waterbed), whereas the percentages of score 2 were 14.0 ± 1.4, 2.3 ± 1.5, and 5.0 ± 1.4, and of score 3 were 3.0 ± 0.4, 0.2 ± 0.4, and 0.4 ± 0.4. Cows on CPk had no lesions. Hygiene scores ranged from 1 to 5, with 1 being clean and 5 soiled. The percentages of hygiene score 1 were 0 (compost), 0.4 (RFM), 0.4 (sand), and 0.4 (waterbeds); those with score 2 were 79.0, 84.0 ± 0.01, 73.2 ± 0.01, and 80.4 ± 0.01; with score 3 were 20.3, 15.2 ± 0.01, 23.8 ± 0.01, and 18.6 ± 0.01; with score 4 were 0.8, 0.005 ± 0.001, 0.006 ± 0.001, and 0.025 ± 0.003; and with score 5 was 0 for all bed types. Cows on RFM and waterbeds had improved hygiene compared with cows on sand beds. There was no difference in somatic cell count (SCC) by bed type. The percentage of cows in fourth lactation or greater on waterbeds (19.8 ± 1.8) was greater than those on RFM (13.3 ± 1.6) or on sand (13.5 ± 1.8). The percentage culled was lower for cows on waterbeds than on RFM (22.8 ± 1.5 vs. 29.4 ± 1.4). Score 3 tarsal lesions were correlated (r = 0.60) with SCC. The length of the sand bed was correlated with a greater percentage of mature cows. The SCC was correlated with the percentage of cows reported lame on the day of the visit (r = 0.45) and with neck rail height (r = −0.26). On dairies with RFM, severe lesions (r = 0.60), death losses (r = 0.52), and percentage of the herd reported lame on the day of the visit (r = 0.52) were all correlated with the SCC. Dairies with higher percentages of lesions had higher SCC, death losses, lameness, and culling rates. Adding bedding several times per week may reduce the incidence of lesions

Survey of Dairy Management Practices on One Hundred Thirteen North Central and Northeastern United States Dairies

The objective was to conduct a broad survey of dairy management practices that have an effect on animal well-being. Dairies were visited during the fall and winter of 2005 and 2006 in Wisconsin, Minnesota, Indiana, Iowa, and New York. Data were collected on 113 dairies on colostrum feeding, dehorning, tail-docking, euthanasia methods, producer statements about welfare, use of specialized calf-raising farms (custom), level of satisfaction with calf-raising by producers, and cow behavior. Calves were raised by the owner on 50.4% of dairies; 30.1% were raised on custom farms during the milk-feeding period, 18.6% were custom raised after weaning, and 1% sold calves with the option to buy them back as first-lactation heifers. A total of 51.8% of producers were very satisfied with their current calf-raising methods. Three feedings of colostrum were fed to the calves on 23.9% of dairies, 2 feedings on 39.8% of farms, 1 feeding on 31.0% of farms, and colostrum replacement products were fed on 5.3% of farms. Many farms (61.9%) provided 3.8 L at first feeding. Calves were dehorned at different ages by various methods. By 8 wk, 34.5% of calves were dehorned. By 12 wk, 78.8% of calves were dehorned. The majority of calves were dehorned by hot iron (67.3%). The remainder were dehorned by gouging (8.8%), paste (9.7%), saw (3.5%), or unknown by calf owner (10.6%). Anesthetic use was reported by 12.4% of dairy owners and analgesia use by 1.8%. Tail-docking was observed on 82.3% of dairies. The most common reported docking time was pre- or postcalving (35.2%). The second most commonly reported time was d 1 (15.4%). Rubber band was the most common method (92.5%), followed by amputation (7.5%). Three dairies amputated precalving, 1 at 2 mo and 3 at d 1 or 2. Cow hygiene was the most common reason given to dock (73.5%), followed by parlor worker comfort (17.4%) and udder health (1.0%). Producers reported 2.0% of cows obviously lame. Gun was the preferred euthanasia method (85.7%), followed by i.v. euthanasia (8.0%), live pick-up (1.8%), and nondisclosure (3.5%). Most producers (77.9%) stated that cows were in an improved environment as compared with 20 yr ago, whereas 8.0% stated conditions were worse, and 14.2% were undecided. Dairies with higher percentages of cows that either approached or touched the observer had lower somatic cell counts. The survey results showed management practices that were important for animal welfare