Defying deprivation: a cross-sectional analysis of area level health resilience in England.

Previous research has found evidence that some economically deprived areas in England exhibit 'health resilience' in terms of lower than expected mortality rates. Consistent with earlier research we analysed area 'resilience' for parliamentary constituencies and our work extends previous research by including measures of morbidity. Standardised Morbidity Ratios (SMRs) of self-reported general health, limiting long-term illness, emergency hospital admissions, and CHD hospital admissions were derived from the 2001 UK Census and 2001 Hospital Episodes Statistics, and combined into a Composite Morbidity Index (CMI). Area variation in the CMI was compared with previous findings about mortality rates. Multiple Correspondence Analysis (MCA) was used to test the associations between area level 'health resilience' and ethnic composition, residential mobility, employment type, housing tenure, and an indicator of social cohesion. Nine areas were 'resilient' in terms of morbidity. Only four areas of England exhibited 'health resilience' in terms of both mortality and morbidity. MCA revealed that there may be several factors associated with greater 'health resilience'.

Effects of floor space during transport and journey time on indicators of stress and transport losses of market-weight pigs.

The effects of floor space on the trailer and journey time during transport from the farm to the packing plant on indicators of stress (open-mouth breathing, muscle tremors, and skin discoloration) and on the incidence of transport losses (dead on arrival, nonambulatory, noninjured, and nonambulatory, injured) were evaluated in a study involving 160 loads of market-weight pigs (BW 124.7 ± 4.38 kg) using a split-plot design with a 2 × 6 factorial arrangement of treatments: 1) journey time [main plot; short (<1 h) and long (3 h)] and 2) floor space (subplot; 0.396, 0.415, 0.437, 0.462, 0.489, and 0.520 m(2)/pig, which is equivalent to 0.317, 0.332, 0.350, 0.370, 0.391, and 0.416 m(2)/100 kg of BW, respectively). Two consecutively loaded trailers were randomly allotted to journey time treatment. Floor space treatments were compared in the front 3 compartments on the top and bottom decks of the trailer and were created by varying the number of pigs per compartment, which confounds the effect of floor space with group size. Of the 17,652 pigs transported in 954 test compartments, 0.24% died or became nonambulatory. Neither journey time nor floor space had an effect (P > 0.05) on the incidence of dead and nonambulatory, injured pigs, or on total transport losses. There were interactions (P < 0.05) between journey time and floor space treatments for the incidences of nonambulatory, noninjured pigs and open-mouth breathing. For 2 of the smallest floor spaces (0.415 and 0.437 m(2)/pig), the incidence of nonambulatory, noninjured pigs was greater on short than on long journeys; for the other 4 floor spaces there was no effect (P > 0.05) of journey time. The incidence of open-mouth breathing for the 3 smallest floor spaces was greater (P < 0.05) for short than long journeys, whereas there was no effect (P > 0.05) of journey time for the 3 greatest floor spaces. The frequency of skin discoloration was greater (P < 0.001) for pigs transported at the 2 smallest floor spaces compared with the other 4 floor spaces. In summary, short journey time increased the frequency of indicators of stress after unloading at the plant for pigs transported at smaller floor spaces and also increased the incidence of nonambulatory, noninjured pigs at 2 of the 3 smallest floor spaces. However, neither transport floor space nor journey time had an effect on total losses.

Effects of multiple concurrent stressors on rectal temperature, blood acid-base status, and longissimus muscle glycolytic potential in market-weight pigs.

Sixty-four market-weight (130.0 +/- 0.65 kg) barrows (n = 16) and gilts (n = 48) were used in a split-plot design with a 2 x 2 x 2 factorial arrangement of treatments: 1) handling intensity (gentle vs. aggressive), 2) transport floor space (0.39 vs. 0.49 m(2)/pig), and 3) distance moved during handling (25 vs. 125 m) to determine the effects of multiple concurrent stressors on metabolic responses. For the handling intensity treatment, pigs were moved individually approximately 50 m through a handling course with either 0 (gentle) or 8 (aggressive) shocks from an electric goad. Pigs were loaded onto a trailer and transported for approximately 1 h at floor spaces of either 0.39 or 0.49 m(2)/pig. After transport, pigs were unloaded, and the distance moved treatment was applied; pigs were moved 25 or 125 m through a handling course using livestock paddles. Rectal temperature was measured, and blood samples (to measure blood acid-base status) were collected 2 h before the handling intensity treatment was applied and immediately after the distance moved treatment was applied. A LM sample to measure glycolytic potential was collected after the distance moved treatments on a subset of 32 pigs. There were handling intensity x distance moved interactions (P < 0.05) for several blood acid-base measurements. In general, there was no effect of distance moved on these traits when pigs were previously handled gently. However, when pigs were previously handled aggressively, pigs moved 125 compared with 25 m had greater (P < 0.05) blood lactate and less (P < 0.05) blood pH, bicarbonate, and base-excess. Pigs transported at 0.39 compared with 0.49 m(2)/pig had a greater (P < 0.01) increase in creatine kinase values; however, transport floor space did not affect any other measurements. Data were analyzed by the number of stressors (the aggressive handling, restricted transport floor space, and 125-m distance moved treatments) experienced by each pig (0, 1, 2, or 3). As the number of stressors experienced by the pig increased, rectal temperature, blood lactate, and LM lactate increased linearly (P

Effects of season and distance moved during loading on transport losses of market-weight pigs in two commercially available types of trailer.

This study evaluated effects of trailer design and season on physical indicators of stress during loading and unloading and transport losses (dead and nonambulatory pigs) in market-weight pigs (BW = 129.6 +/- 0.40 kg). A total of 109 trailer loads of pigs (n = 17,256 pigs) from 1 farm were used in a randomized complete block design with a 2 x 4 factorial arrangement of treatments: 1) trailer design (potbelly vs. straight-deck) and 2) season (spring vs. summer vs. fall vs. winter). A subset of loads (n = 42) was used to examine effect of distance pigs were moved during loading [short (<24 m) vs. long (47 to 67 m)] on physical indicators of stress and transport losses. This study was conducted on 7 d per season at 1 farm with 4 loads (2 on potbelly and 2 on straight-deck trailers) being transported each day to 1 commercial packing plant. Pigs from different farm groups were mixed on the trailer and provided with 0.45 m(2)/pig floor space during an approximately 4-h journey to the plant. The percentage of pigs exhibiting open-mouth breathing, skin discoloration, and muscle tremors was recorded during loading and unloading. Additionally, dead pigs on arrival at the plant and nonambulatory pigs at the farm and at the plant were recorded. Effects of trailer design on open-mouth breathing and skin discoloration during unloading were dependent on season (trailer design x season interaction; P < 0.05). Pigs unloaded from potbelly trailers had a greater (P < or = 0.05) incidence of open-mouth breathing in the spring and summer and a greater (P < 0.05) incidence of skin discoloration in the spring, summer, and winter than pigs unloaded from straight-deck trailers. The incidence of total nonambulatory pigs at the plant was greater (P < 0.05) in the winter than in the spring and summer. The long compared with short distance moved treatment resulted in a greater (P = 0.001) incidence of open-mouth breathing and skin discoloration during loading and tended (P = 0.06) to increase the incidence of nonambulatory pigs at the farm. However, there was no effect of trailer design, season, or loading distance on total losses at the plant. In summary, physical indicators of stress (open-mouth breathing and skin discoloration) were increased with the long distance moved during loading treatment and were greater during unloading for potbelly than straight-deck trailers; however, trailer design, season, and loading distance had minimal effects on total transport losses.

Frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead and nonambulatory-noninjured pigs on arrival at the packing plant.

Four Midwestern packing plants (designated as plants A, B, C, and D) were visited on 53 occasions, and tissue samples were collected postmortem from a total of 2,019 pigs to determine the frequency of the HAL-1843 mutation of the ryanodine receptor gene in dead (DOA), nonambulatory-noninjured (NANI), and normal animals. The sampled pigs came from approximately 130,000 animals from 454 farms and were transported on 861 trailer loads, with an average of 152 pigs/load and an average pig live BW/load of 125 (SD 7.02) kg/pig. Frequency of animals with the HAL-1843 mutation was low, with only 2.7% of the pigs being either homozygous recessives (nn, 0.45%) or carriers (Nn, 2.3%) for the mutation and 97.3% of the pigs being homozygous for the normal allele (NN). The mutation was present in all 3 classes of pig, with 1.8% of normal, 1.8% of NANI, and 4.7% of DOA animals having at least 1 copy. Two of the plants (A and C) had a greater frequency (P < 0.05) of carrier (3.7 and 3.5 vs. 1.1 and 1.0 for plants A and C vs. B and D, respectively) and homozygous recessive (1.0 and 0.9 vs. 0.0 and 0.0, respectively) animals than the others (plants B and D). There was a greater frequency (P < 0.05) of carriers in DOA animals than in the normal or NANI pigs (3.7 vs. 1.7 and 1.5 for DOA vs. normal and NANI, respectively). The 55 pigs that had at least 1 copy of the mutation came from 53 farms; therefore, the mutation was relatively widespread, being present in approximately 11% of the farms sampled. Although the HAL-1843 mutation is still present in commercial pig populations in the United States, its low frequency in DOA and NANI pigs suggests that it is not a major cause of these transport losses.

Space allowance for dry, pregnant sows in pens: body condition, skin lesions, and performance.

Different floor space allowances for dry, pregnant sows in pens were evaluated to determine the impacts of space on sow performance, productivity, and body lesions during 2 consecutive farrowings. Treatment groups of 5 sows/pen were assigned to 1.4, 2.3, or 3.3 m(2) of floor space/sow or of 5 sows in individual stalls (1.34 m(2)). The experiment consisted of 6 replications (blocks 1 to 6), and within each block measurements were recorded for 2 consecutive pregnancies and farrowings. A total of 152 sows were measured at 1 farrowing, and 65 of those sows were measured at the successive farrowing (n = 217 records). Performance traits were BCS, BW, backfat (BF), days until rebred, and proportion culled. Litter traits were number of piglets born alive, male:female ratio, and proportions of stillborn, mummified, or dead piglets after birth. Litter performance measures were mean piglet BW and gain and litter BW. Lesion scores were assessed for several body regions. There were treatment and parity effects and interactions for several traits. An interaction of space treatment and parity occurred for sow mean BW, d-110 BW, BF, litter size, and litter and piglet BW and gain, with most effects in parity 2, 3, and 4 sows. Space affected sow mean (P < 0.001) and d-110 BW (P < 0.05) and mean BF and adjusted BF (P < 0.001); sows in pens at

Effects of proportion of pigs removed from a group and subsequent floor space on growth performance of finishing pigs.

The effects of the proportion of pigs removed from an established group and subsequent floor space on growth performance during the final 19 d of the finishing period were evaluated using 28 pens of mixed-sex crossbred pigs (mean initial BW = 113.4 +/- 0.57 kg; n = 1,456; approximately 52 pigs per pen). A randomized block design was used with four pig-removal treatments: 1) 0% of pigs removed [Control], 2) approximately 25% of pigs removed, 3) approximately 50% of pigs removed, and 4) approximately 50% of pigs removed and floor and feeder spaces/pig decreased to equal those of Control. A block consisted of four pens with the same number of pigs and sex ratio per pen and with similar initial BW. Pens within blocks were randomly allocated to treatment, and the heaviest animals were removed from Treatments 2, 3, and 4 at the start of the study. Group size and floor space/pig for Treatments 1, 2, 3, and 4 were 52 and 0.65 m(2), 39 and 0.87 m(2), 26 and 1.30 m(2), and 26 and 0.65 m(2), respectively. Each pen contained a six-place feeder that provided 212 cm of total trough space; however, only three-places were accessible to pigs on Treatment 4. Compared with Controls, removing 25 or 50% of pigs resulted in increased (P < 0.001) ADG by 20.6 and 21.0%, ADFI by 10.8 and 7.9%, and G:F by 7.7 and 14.3%, respectively. Average daily gain by pigs on Treatment 4 (50% removal rate and decreased floor and feeder spaces) was greater (P < 0.05) than that of the Controls, but lower (P < 0.05) than that of Treatment 3 pigs (50% removal rate, no adjustment in floor or feeder spaces). No differences were observed among treatments for either morbidity or mortality. These results indicate that removing 25 or 50% of the heaviest pigs from groups of finishing pigs increased growth rate of the remaining pigs, and that the improved performance was only partly due to increased floor and feeder spaces.

Effect of restricted postweaning growth resulting from reduced floor and feeder-trough space on pig growth performance to slaughter weight in a wean-to-finish production system.

The effect of reduced pig growth rate postweaning as a result of restricted floor space and feeder trough space on subsequent growth to slaughter was investigated in a wean-to-finish system. Crossbred pigs (n = 1,728) were used in a randomized block design with a 2 x 2 x 2 factorial arrangement of treatments: 1) floor space (high [0.630 m2/pig] vs. low floor space [0.315 m2/pig]), 2) feeder trough space (unrestricted [4 cm/pig] vs. restricted feeder trough space [2 cm/pig]), and 3) period of imposing floor- and feeder-trough-space treatments (12 vs. 14 wk postweaning). Growth performance was measured from weaning (5.5 +/- 0.01 kg of BW; 17 d of age) to slaughter (the end of wk 25 postweaning). From the end of the treatment period to the end of wk 25, pigs on all treatments had the same floor and feeder trough space. Pigs with low floor space had lower (P < 0.01) ADG, ADFI, and gain:feed ratio than those with high floor space, and were therefore lighter (P < 0.05) at the end of the postweaning treatment period. Pigs given the restricted feeder trough space had lower (P < 0.05) ADFI, similar (P > 0.05) ADG, and higher (P < 0.01) gain:feed ratio than those with unrestricted feeder trough space during the treatment period. Pigs in the 14-wk treatment period had higher (P < 0.01) ADG and ADFI, but lower gain:feed than those in the 12-wk treatment during that period. In the subsequent period, from the end of treatment to wk 25, there was an interaction (P < 0.05) between floor space and treatment period; the difference in ADG and gain:feed for pigs on low vs. high floor space was greater for the 14-wk than the 12-wk treatment period. However, low-floor-space pigs tended (P = 0.06) to be lighter than high-floor-space pigs at the end of wk 25 postweaning. Neither feeder trough space nor treatment period affected pig growth performance during the period from the end of treatment to wk 25. Carcass backfat and longissimus depths at the end of wk 25 were not influenced (P > 0.05) by treatment. In summary, pigs with restricted growth due to low floor space until either 12 or 14 wk postweaning had increased growth and feed efficiency in the subsequent period to wk 25 postweaning, with only a slight effect on BW and no effect on carcass measures.

Impact of early postweaning growth rate as affected by diet complexity and space allocation on subsequent growth performance of pigs in a wean-to-finish production system.

The objective was to evaluate the effect of restricted early postweaning growth rate due to diet complexity, pen space, or both on subsequent growth to market in a wean-to-finish system. Pigs (n = 1,728) were used in a randomized block design with a 2 x 2 factorial arrangement of treatments: 1) diet complexity (Complex vs Simple) and 2) space allocation (Unrestricted vs Restricted). Treatments were imposed for the first 8 wk after weaning (period 1) and growth was measured from weaning (5.0 +/- 0.01 kg body weight; 15 d of age) to the end of wk 23 postweaning. The Simple diet was based on corn-soybean meal with minimal inclusion of milk products, processed cereals, and animal protein-based ingredients compared to the Complex diet. Floor and feeder-trough spaces were 0.63 m2 and 4 cm and 0.21 m2 and 2 cm per pig for Unrestricted and Restricted space treatments, respectively. From the end of wk 8 to end of wk 23 (period 2), pigs on all treatments had the same floor and feeder spaces and were fed common diets. There was no interaction (P > 0.05) between diet and space treatments. In period 1, Simple diets resulted in similar average daily feed intake (ADFI; 639 vs 650 +/- 5.4 g; P > 0.05), but lower average daily gain (ADG; 408 vs 424 +/- 3.8 g; P < 0.01) and gain:feed ratio (0.64 vs 0.65 +/- 0.002; P < 0.001), and lighter body weight (2.8%; P < 0.01) compared to the Complex diets. In period 2, growth was not affected (P > 0.05) by previous diet complexity, and pig body weight was similar (114.4 vs 114.4 +/- 0.37 kg, P > 0.05) at the end of wk 23. In period 1, pigs with Restricted space had lower ADG (398 vs 434 +/- 3.8 g; P < 0.001), ADFI (621 vs 668 +/- 5.4 g; P < 0.001), and gain:feed ratio (0.64 vs 0.65 +/- 0.002; P < 0.01), and were lighter at the end of wk 8 (6.5%; P < 0.001) than those with Unrestricted space. However, in period 2, pigs with Restricted space had higher (P < 0.01) ADG (3%), ADFI (2%), and gain:feed ratio (3%) than those with Unrestricted space, and body weight was similar (114.5 vs 114.3 +/- 0.37 kg; P > 0.05) at end of wk 23. Carcass backfat and loin-eye depth at market body weight were influenced by neither diet nor space treatment. Using a simple diet program and restricted space allowance immediately postweaning resulted in a lower early growth rate, but had no impact on pig body weight or carcass measures at market.

Effects of feeder-trough space and variation in body weight within a pen of pigs on performance in a wean-to-finish production system.

Two studies were carried out with the same group of pigs within a wean-to-finish system. In Study 1 (weaning to wk 8 postweaning), the effect of feeder-trough space in pens that were double-stocked on pig growth was evaluated. In Study 2 (end of wk 8 to 112 +/- 1.5 kg BW), the effect of variation in pig BW within a pen on growth was investigated. In Study 1, a randomized block design was used to compare two feeder-trough space treatments (Double [4 cm/pig] vs Control [2 cm/pig]). Pigs (n = 1,728) were randomly allocated at weaning (5.4 +/- 0.01 kg BW; 16 d of age) to mixed-sex pens (8 pens/treatment) of 108 pigs/pen on the basis of BW. Floor-space (0.30 m2/pig) and drinker allocation (13 pigs/drinker) were the same for both treatments. Two six-place (35 cm/place) feeders were positioned together in the center of each pen and were accessible from both sides. For the Double treatment, both feeders contained feed, whereas for the Control only one feeder contained feed. In Study 2, a randomized block design was used to compare three BW/variation in BW treatments: 1) Heavy BW/Low variation, 2) Light BW/Low variation, and 3) Mixed BW/Normal variation. The double-stocked pens of pigs from within previous feeder-trough space treatment were split into two groups of 54 pigs (equal sex ratio) having either high or low BW variation within pen. Pigs had free access to feed and water throughout the studies. In Study 1, doubling feeder-trough space did not affect (P > 0.05) pig growth from weaning to the end of wk 6. From wk 6 to 8, pigs on the Double treatment compared to the Control treatment had higher (P < 0.05) ADG and were heavier (P < 0.05), but had similar (P > 0.05) ADFI and gain:feed ratio. In Study 2, pen-BW treatment did not impact (P > 0.05) ADG or gain:feed ratio; however, Heavy/Low had greater (P < 0.01) ADFI than Light/Low with Mixed/Normal being intermediate for ADFI. At 112 kg BW, CV of BW within a pen was similar (P > 0.05) across treatments; however, days to market BW was greater (P < 0.001) for Light/Low than Heavy/ Low with Mixed/Normal being intermediate. In summary, increasing feeder-trough space from 2 to 4 cm per pig increased daily gain after wk 6 postweaning in double-stocked pens of pigs; however, sorting pigs on the basis of BW when splitting pens did not impact growth rate or variation in BW within a pen at market BW.

Effects of double stocking and weighing frequency on pig performance in wean-to-finish production systems.

Two studies were carried out in different wean-to-finish barns to determine the effects of double stocking on pig growth performance. In Study 1, pigs (n = 1,560) were used in a randomized complete block design with a 2 x 2 factorial arrangement of treatments: initial stocking treatment (Single [52 pigs/pen] vs Double [104 pigs/pen] stocked for 10 wk after weaning) and weighing frequency (High [12 times during the study] vs Low [3 times]) on pig performance from weaning (5.9+/-0.01 kg BW; 17 d of age) to harvest (114+/-0.67 kg BW). Floor and feeder space per pig were 0.650 m2 and 4 cm and 0.325 m2 and 2 cm for the single- and double-stocked treatments, respectively. In Study 2, pigs (n = 1,458) were used in a randomized complete block design to evaluate two initial stocking treatments (Single [27 pigs] vs Double [54 pigs] stocked for 10 wk after weaning) on pig performance from weaning (4.8+/-0.01 kg BW; 15 d of age) to harvest (24 wk after weaning). Floor and feeder space per pig were 0.640 m2 and 3.4 cm and 0.320 m2 and 1.7 cm for single- and double-stocked pens, respectively. In both studies, double-stocked pigs were split at the end of wk 10 into two equal-sized groups of similar mean BW and CV of BW, and one group was moved to a different pen in the same building. In Study 1, performance was not affected (P > 0.10) by frequency of weighing. For the first 10 wk after weaning, the Double compared to the Single treatment had lower ADG (7.7 and 7.9%, for Studies 1 and 2, respectively; P < 0.001) and lighter pigs at wk 10 (6.8 and 7.3%, respectively; P < 0.001). During the first 10 wk in Study 1, Double compared to the Single pigs had lower ADFI (7%; P < 0.001) but similar gain:feed (P > 0.10). From wk 11 to harvest, pigs on Double and Single treatments had similar (P > 0.10) ADG in both studies and, in Study 1, ADFI was unaffected by initial stocking treatment, but double-stocked pigs had greater gain:feed (4%, P < 0.01). Double-stocked pigs required an additional 2 d to reach a fixed harvest BW (P < 0.05) in Study 1 and were lighter (4%; P < 0.05) at 24 wk after weaning in Study 2. Carcass measures were similar (P > 0.10) for double- and single-stocked pigs. Double-stocked pigs that were moved at the end of 10 wk had growth performance similar (P > 0.10) to those that remained in the original pen. In summary, double stocking reduced growth rate to 10 wk after weaning but subsequently had no effect on growth rate and improved feed efficiency.

A screen for sequences up-regulated during heterocyst development in Anabaena sp. strain PCC 7120.

A plasmid library of small genomic fragments from the cyanobacterium Anabaena sp. strain PCC 7120 was screened for sequences whose transcripts increase in abundance during a heterocyst development time course. A total of 350 clones were analyzed, representing 1-2% of the Anabaena sp. strain PCC 7120 genome. Twenty-seven clones (8%) showed some degree of up-regulation after nitrogen starvation. The increase in transcript abundance ranged from 1.2-fold to 3.5-fold. Further analysis of the expression of some of the sequences using Northern blots suggested that the up-regulation values calculated from the screen are underestimates. The collection of up-regulated clones includes novel genes, previously characterized genes, and genes identifiable by similarity to known genes. One of the novel genes has been shown to be required for heterocyst function, and the sequence similarities and expression patterns of some of the others suggest that they may play a role in heterocyst development.

Effect of group size on pig performance in a wean-to-finish production system.

Crossbred pigs (n = 1,400) were used to evaluate the effect of group size (25 vs 50 vs 100 pigs/pen) in a wean-to-finish production system on growth performance and carcass measures. Pigs were weaned at 17 d (range = 15 to 19) of age with a mean initial BW of 5.9 +/- 0.02 kg and taken to a final mean pen weight of 116 +/- 0.9 kg. A 10-phase dietary regimen was used, and pigs had free access to feed and water. Feeder-trough space (4.3 cm/pig) and floor-area allowance (0.68 m2/pig) were the same for all group sizes. Compared to groups of 25, pigs in groups of 50 and 100 animals were lighter (P < 0.001) at the end of wk 8 after weaning and had lower (3%, P < 0.01) ADG and gain:feed (G/F) but similar (P > 0.05) ADFI during the first 8 wk of the study. At the end of the study, pig weight and the coefficient of variation in pig weight within a pen were similar (P > 0.05) across group sizes. During the period from 8 wk after weaning to the end of the study, pigs in groups of 100 compared to 50 animals had greater (3%, P < 0.01) ADG, and pigs in groups of 25 were intermediate for ADG. Average daily feed intake during this period was similar (P > 0.05) for all group sizes; however, G/F was greater (3%, P < 0.01) for groups of 100 compared to 25 or 50 animals. For the overall study period, ADG, ADFI, and G/F from weaning to slaughter weight were similar across group sizes (P > 0.05; 655, 648, and 658 g; 1,759, 1,755, and 1,759 g; and 0.37, 0.37, and 0.37; for ADG, ADFI, and G/F, respectively, for groups of 25, 50, and 100 pigs, respectively). Mortality was similar (P > 0.05) across group sizes; however, morbidity (pigs removed due to poor health or injury) was higher in groups of 25 pigs compared to the other two group sizes (7.0, 3.5, and 3.9% for groups of 25, 50, and 100, respectively; P < 0.05). Group-size treatment did not affect (P > 0.05) carcass dressing percentage, backfat thickness, or loin-eye depth. In summary, growth performance from weaning to market weight was not affected by group size.

Feeder location did not affect performance of weanling pigs in large groups.

Crossbred pigs weaned at 17 d of age (n = 1,760; mean initial BW = 5.6 +/- 0.7 kg) were used in two 4-wk trials (four replicates per trial) to evaluate the effects of three pen designs on pig performance. The designs were 1) large group size (100 pigs/pen) with five two-sided feeders in a single, central location in the pen; 2) large group size (100 pigs/pen) with five two-sided feeders in multiple (five) locations in the pen; and 3) small group size (20 pigs/pen) with a single two-sided feeder in a central location in the pen. Each feeder provided two 20.3-cm-wide feeding places on each side. Pigs had free access to feed and water. Feeder-trough space (4 cm/pig) and floor-area allowance (0.17 m2/pig) were the same for all treatments. Pigs in the large-group treatments were lighter (15.6 and 15.6 vs 16.0 kg; P < 0.01) at the end of wk 4 and had lower ADG (358 and 357 vs 373 g; P < 0.01) and ADFI (510 and 521 vs 544 g; P < 0.01) during wk 2 through 4 than pigs in small groups. Gain:feed ratio was similar (P > 0.05) for all treatment groups throughout the study. For large groups, feed disappearance from each of the five feeders was similar (P > 0.05) for both multiple- and single-location treatments. In summary, large group size reduced pig growth performance, but the approach to providing multiple feeding locations that was employed in this experiment did not increase feed intake or growth performance of pigs in the large groups.

Group size and floor-space allowance can affect weanling-pig performance.

Crossbred weanling piglets (n = 1,920; mean initial BW, 5.3 +/- .7 kg) were used in two 9-wk trials employing a randomized block design in a 2 x 2 factorial arrangement of treatments to determine effects of group size (20 [Small = S] or 100 [Large = L] pigs/pen) and floor-space allowance (calculated requirement [CR] or calculated requirement less 50% of estimated "free space" [CR-50]) on growth performance. Free space was estimated for each group size. From wk 1 through 4 after weaning, S and L groups at CR were allowed a floor space of .17 m2/pig, and at CR-50, S and L groups were allowed .15 m2/pig and .13 m2/pig, respectively. From wk 5 through 9 after weaning, all CR treatment pigs were provided a floor space of .38 m2/pig, and for the CR-50 treatment, S and L pigs were allowed .32 m2/pig and .28 m2/pig, respectively. Piglets had free access to feed and water. Feeder-trough space per pig was the same for both group sizes. Feed-intake data were collected for only wk 1 through 4. Group size by floor-space allowance interactions (P < .05) were found for gain/feed ratio (G/F) for wk 1 and wk 2 through 4, but not for wk 1 through 4. Piglets in L groups were lighter (P < .001) at the end of wk 1, 4, and 9 by 2, 4, and 5%, respectively, and had lower ADG (6%; P < .001) throughout the trial than S piglets. During wk 1 through 4, feed intake was lower (7%, P < .001) in L piglets than in S piglets, but G/F was similar (P > .05). Piglets in CR groups had greater ADG (5%; P < .01) throughout the trial, with a greater G/F (P < .05) for wk 1 through 4, and were heavier (P < .01) than those in CR-50 groups at the end of wk 4 (3%) and 9 (4%). Pigs in L groups had a greater within-pen coefficient of variation in BW at the end of wk 9 than pigs in S groups. Large groups and reduced floor-space allowance reduced piglet growth performance in the nursery.

Characterization of devH, a gene encoding a putative DNA binding protein required for heterocyst function in Anabaena sp. strain PCC 7120.

The devH gene was identified in a screen for Anabaena sp. strain PCC 7120 sequences whose transcripts increase in abundance during a heterocyst development time course. The product of devH contains a helix-turn-helix motif similar to the DNA binding domain of members of the cyclic AMP receptor protein family, and the protein is most closely related to the cyanobacterial transcriptional activator NtcA. devH transcripts are barely detectable in vegetative cells and are induced approximately fivefold after nitrogen starvation. This induction is absent in the two developmental mutants hetR and ntcA. The gene is expressed as monocistronic transcripts with multiple 5' termini, and the approximately 500-bp region 5' to devH was shown to have promoter activity in vivo. The devH gene was insertionally inactivated by the integration of plasmid sequences within the open reading frame. Nitrogen starvation of the devH mutant induces heterocysts of wild-type morphology, but the mutant is inviable in the absence of fixed nitrogen and unable to reduce acetylene aerobically.

Endothelial modulation of neural sympathetic vascular tone in canine skeletal muscle.

The effect of nitric oxide synthase (NOS) inhibition and endothelin-A (ETA)-receptor blockade on neural sympathetic control of vascular tone in the gastrocnemius muscle was examined in anesthetized dogs under conditions of constant flow. Muscle perfusion pressure (MPP) was measured before and after NOS inhibition (Nomega-nitro-L-arginine methyl ester; L-NAME) and ETA-receptor blockade [cyclo-(D-Trp-d-Asp-Pro-D-Val-Leu); BQ-123]. Zero and maximum sympathetic nerve activities were achieved by sciatic nerve cold block and stimulation, respectively. In group 1 (n = 6), MPP was measured 1) before nerve cold block, 2) during nerve cold block, and 3) during nerve stimulation. Measurements under these conditions were repeated after L-NAME and then BQ-123. The same protocol was followed in group 2 (n = 6) except that the order of L-NAME and BQ-123 was reversed. MPP and muscle vascular resistance (MVR) increased after L-NAME and then decreased to control values after BQ-123. MVR decreased after BQ-123 alone and, with the addition of L-NAME, increased to a level not different from that observed during the control period. MVR fell during nerve cold block. This response was not affected by administration of L-NAME followed by BQ-123, but it was attenuated by administration of BQ-123 before L-NAME. The constrictor response during sympathetic nerve stimulation was enhanced by L-NAME; no further effect was observed with BQ-123, nor was the response affected when BQ-123 was given first. These findings indicate that endothelin contributes to 1) basal vascular tone in skeletal muscle and 2) the increase in skeletal muscle vascular resistance after NOS inhibition. Finally, nitric oxide "buffers" the degree of constriction in skeletal muscle vasculature during maximal sympathetic stimulation.

Toppled television sets cause significant pediatric morbidity and mortality.

OBJECTIVE: To quantify pediatric injuries and deaths that result from toppled television sets. DESIGN: Retrospective analysis of incident files compiled by the US Consumer Product Safety Commission (CPSC) data systems and The Children's Hospital of Alabama (TCHA) inpatient medical records. SETTING: United States, January 1990-June 1997. TCHA, May 1995-October 1997. MAIN OUTCOME MEASURES: Morbidity or mortality as a result of a television set falling onto a child. RESULTS: Over the 7-year period from January 1990 to June 1997, 73 cases that involved falling television sets were reported to the CPSC, including 28 deaths. The mean age of all victims was 36 months (SD +/- 25.4 months). The mean age of those who died was 31 months (SD +/- 22 months). Females accounted for 42 incidents (58%) and 19 deaths (68%). The most common anatomic site of injury was the head, which accounted for 72% of cases investigated by CPSC personnel. Of the 14 deaths further investigated by the CPSC, head injury was responsible for 13, with a generalized crushing injury accounting for the other. Of the 45 cases in which data were available, dressers or stands were identified as the television support 76% of the time. The TCHA database yielded five additional cases, including one death, with demographics similar to the CPSC data. CONCLUSION: Serious injury and death can occur as a result of children toppling television sets from elevated locations in the home. The furniture on which a television set is situated is of fundamental importance. An estimate of overall risk to the population is impossible to determine from these data. In light of 73 reported cases with 28 deaths; however, injury prevention counseling and other strategies supporting in-home safety should include a secure and child-safe location for television sets. Attention should be paid to safer design and placement of this ubiquitous product. television, wounds and injuries, accidents, human, infants, children.