The shifting shelf task: a new, non-verbal measure for attentional set shifting.

Attentional set shifting is a core ingredient of cognition, allowing for fast adaptation to changes in the environment. How this skill compares between humans and other primates is not well known. We examined performance of 3- to 5-year-old children and chimpanzees on a new attentional set shifting task. We presented participants with two shelves holding the same set of four boxes. To choose the correct box on each shelf, one has to switch attention depending on which shelf one is currently presented with. Experiment 1 (forty-six 3- to 5-year olds, predominantly European White) established content validity, showing that the majority of errors were specific switching mistakes indicating failure to shift attention. Experiment 2 (one hundred and seventy-eight 3- to 6-year olds, predominantly European White) showed that older children made fewer mistakes, but if mistakes were made, a larger proportion were switching mistakes rather than 'random' errors. Experiment 3 (52 chimpanzees) established suitability of the task for non-human great apes and showed that chimpanzees' performance was comparable to the performance of 3- and 4-year olds, but worse than 5-year olds. These results suggest that chimpanzees and young children share attentional set shifting capacities, but that there are unique changes in the human lineage from 5 years of age.

Correlations between serum levels of beta amyloid, cerebrospinal levels of tau and phospho tau, and delayed response tasks in young and aged cynomolgus monkeys (Macaca fascicularis).

BACKGROUND: In an attempt to explore cynomolgus monkeys as an animal model for Alzheimer's disease, the present study focused on the Alzheimer's biomarkers beta amyloid 1-42 (Aß42 ) in serum, and total tau (t-tau) and phosphorylated tau (p-tau) levels in cerebrospinal fluid. METHODS: We measured biomarker levels in Young and Aged cynomolgus monkeys and correlated these with performance on three delayed response tasks. RESULTS: The Aß42 concentration of the Aged monkeys was significantly lower than in the Young subjects, while the t-tau and p-tau did not significantly differ between the groups. The Young subjects performed significantly better than the Aged individuals on the memory tests. Only Aß42 levels were significantly correlated with performance in the three delayed response tasks. CONCLUSIONS: Circulating Aß42 levels were lower in Aged monkeys and were correlated with inferior performance on delayed response tasks in Aged animals; therefore, both measures may be useful in establishing cynomolgus monkeys as models for studies of AD.

Musculoskeletal response of dystrophic mice to short term, low intensity, high frequency vibration.

OBJECTIVES: We aimed to identify parameters of low-intensity vibration that initiate the greatest osteogenic response in dystrophin-deficient mice and determine vibration safety for diseased muscle in three separate studies. METHODS: Study1: Mdx mice were randomized into seven vibration treatments and 14 d later, plasma osteocalcin and tibial osteogenic gene expression were compared among treatments. Study2: Three days of vibration was compared to other modalities known to elicit muscle injury in mdx mice. Study3: Dystrophic mice with more severe phenotypes due to altered utrophin were subjected to 7 d vibration to determine if muscle injury was induced. Muscle torque and genes associated with inflammation and myogenesis were assessed in Studies 2-3. RESULTS: Two sets of parameters (45 Hz 0.6 g and 90 Hz 0.6 g) evoked osteogenic responses. 45 Hz upregulated alkaline phosphatase and tended to upregulate osteoprotegerin without altering RANKL, and 90 Hz simultaneously upregulated osteprotegerin and RANKL. Thus, subsequent muscle studies utilized 45 Hz. Vibration for 3 or 7 d was not injurious to dystrophic muscle as shown by the lack of differences between vibrated and non-vibrated mice in torque and gene expression. CONCLUSIONS: Results indicate that vibration at 45 Hz and 0.6 g is safe for dystrophic muscle and may be a therapeutic modality to improve musculoskeletal health in DMD.

Efficacy and safety of an attenuated live QX-like infectious bronchitis virus strain as a vaccine for chickens.

The attenuation of infectious bronchitis (IB) QX-like virus strain L1148 is described. The virus was passaged multiple times in embryonated specific pathogen free (SPF) chicken eggs, and at different passage levels samples were tested for safety for the respiratory tract and kidneys in 1-day-old SPF chickens. There was a clear decrease in pathogenicity for the respiratory tract and kidneys when the virus had undergone a large number of passages. Passage level 80 was investigated for safety for the reproductive tract in 1-day-old and 7-day-old SPF chickens. In 1-day-old chickens, 12.5% of the vaccinated birds had macroscopic lesions. No lesions were observed if the chickens had been vaccinated at 7 days of age. Passage level 80 was investigated for its ability to spread from vaccinated to non-vaccinated chickens and for dissemination in the body. The virus was able to spread from vaccinated chickens to groups of non-vaccinated chickens, and in the vaccinated birds the virus was found frequently in oro-pharyngeal and cloacal swabs. A fragment of the hypervariable region of the S1 protein of passage level 80 was sequenced and revealed nucleotide changes resulting in two amino acid substitutions. Passage level 80 was given additional passages to levels 82 and 85. Both passage levels were tested for efficacy in SPF chickens and passage level 85 was tested for efficacy in commercial chickens with maternally derived antibodies (MDA) against a challenge with QX-like strain IB D388. In both SPF chickens and chickens with MDA, the vaccines based on strain IB L1148 were efficacious against challenge.

Pilot-scale crossflow-microfiltration and pasteurization to remove spores of Bacillus anthracis (Sterne) from milk.

High-temperature, short-time pasteurization of milk is ineffective against spore-forming bacteria such as Bacillus anthracis (BA), but is lethal to its vegetative cells. Crossflow microfiltration (MF) using ceramic membranes with a pore size of 1.4 µm has been shown to reject most microorganisms from skim milk; and, in combination with pasteurization, has been shown to extend its shelf life. The objectives of this study were to evaluate MF for its efficiency in removing spores of the attenuated Sterne strain of BA from milk; to evaluate the combined efficiency of MF using a 0.8-µm ceramic membrane, followed by pasteurization (72°C, 18.6s); and to monitor any residual BA in the permeates when stored at temperatures of 4, 10, and 25°C for up to 28 d. In each trial, 95 L of raw skim milk was inoculated with about 6.5 log(10) BA spores/mL of milk. It was then microfiltered in total recycle mode at 50°C using ceramic membranes with pore sizes of either 0.8 µm or 1.4 µm, at crossflow velocity of 6.2 m/s and transmembrane pressure of 127.6 kPa, conditions selected to exploit the selectivity of the membrane. Microfiltration using the 0.8-µm membrane removed 5.91±0.05 log(10) BA spores/mL of milk and the 1.4-µm membrane removed 4.50±0.35 log(10) BA spores/mL of milk. The 0.8-µm membrane showed efficient removal of the native microflora and both membranes showed near complete transmission of the casein proteins. Spore germination was evident in the permeates obtained at 10, 30, and 120 min of MF time (0.8-µm membrane) but when stored at 4 or 10°C, spore levels were decreased to below detection levels (≤0.3 log(10) spores/mL) by d 7 or 3 of storage, respectively. Permeates stored at 25°C showed coagulation and were not evaluated further. Pasteurization of the permeate samples immediately after MF resulted in additional spore germination that was related to the length of MF time. Pasteurized permeates obtained at 10 min of MF and stored at 4 or 10°C showed no growth of BA by d 7 and 3, respectively. Pasteurization of permeates obtained at 30 and 120 min of MF resulted in spore germination of up to 2.42 log(10) BA spores/mL. Spore levels decreased over the length of the storage period at 4 or 10°C for the samples obtained at 30 min of MF but not for the samples obtained at 120 min of MF. This study confirms that MF using a 0.8-µm membrane before high-temperature, short-time pasteurization may improve the safety and quality of the fluid milk supply; however, the duration of MF should be limited to prevent spore germination following pasteurization.

Non-human primates use combined rules when deciding under ambiguity.

Decision outcomes in unpredictable environments may not have exact known probabilities. Yet the predictability level of outcomes matters in decisions, and animals, including humans, generally avoid ambiguous options. Managing ambiguity may be more challenging and requires stronger cognitive skills than decision-making under risk, where decisions involve known probabilities. Here we compare decision-making in capuchins, macaques, orangutans, gorillas, chimpanzees and bonobos in risky and ambiguous contexts. Subjects were shown lotteries (a tray of potential rewards, some large, some small) and could gamble a medium-sized food item to obtain one of the displayed rewards. The odds of winning and losing varied and were accessible in the risky context (all rewards were visible) or partially available in the ambiguous context (some rewards were covered). In the latter case, the level of information varied from fully ambiguous (individuals could not guess what was under the covers) to predictable (individuals could guess). None of the species avoided gambling in ambiguous lotteries and gambling rates were high if at least two large rewards were visible. Capuchins and bonobos ignored the covered items and gorillas and macaques took the presence of potential rewards into account, but only chimpanzees and orangutans could consistently build correct expectations about the size of the covered rewards. Chimpanzees and orangutans combined decision rules according to the number of large visible rewards and the level of predictability, a process resembling conditional probabilities assessment in humans. Despite a low sample size, this is the first evidence in non-human primates that a combination of several rules can underlie choices made in an unpredictable environment. Our finding that non-human primates can deal with the uncertainty of an outcome when exchanging one food item for another is a key element to the understanding of the evolutionary origins of economic behaviour. This article is part of the theme issue 'Existence and prevalence of economic behaviours among non-human primates'.

Location and Setting of the Mars InSight Lander, Instruments, and Landing Site.

Knowing precisely where a spacecraft lands on Mars is important for understanding the regional and local context, setting, and the offset between the inertial and cartographic frames. For the InSight spacecraft, the payload of geophysical and environmental sensors also particularly benefits from knowing exactly where the instruments are located. A ~30 cm/pixel image acquired from orbit after landing clearly resolves the lander and the large circular solar panels. This image was carefully georeferenced to a hierarchically generated and coregistered set of decreasing resolution orthoimages and digital elevation models to the established positive east, planetocentric coordinate system. The lander is located at 4.502384°N, 135.623447°E at an elevation of -2,613.426 m with respect to the geoid in Elysium Planitia. Instrument locations (and the magnetometer orientation) are derived by transforming from Instrument Deployment Arm, spacecraft mechanical, and site frames into the cartographic frame. A viewshed created from 1.5 m above the lander and the high-resolution orbital digital elevation model shows the lander is on a shallow regional slope down to the east that reveals crater rims on the east horizon ~400 m and 2.4 km away. A slope up to the north limits the horizon to about 50 m away where three rocks and an eolian bedform are visible on the rim of a degraded crater rim. Azimuths to rocks and craters identified in both surface panoramas and high-resolution orbital images reveal that north in the site frame and the cartographic frame are the same (within 1°).

Effect of storage and subsequent reheating on viability of Listeria monocytogenes on pork scrapple.

We evaluated the fate of Listeria monocytogenes on commercial pork scrapple, a regionally popular, ready-to-eat (RTE) meat. We also conducted an informal survey to address consumer practices for storing and reheating scrapple. Of the 129 consumers who responded to at least one of the eight questions posed in the survey, about half (46.4%; 52 of 112) considered scrapple RTE, the majority (69.7%; 76 of 109) stored it in the refrigerator, and all (100%; 112 of 112) preferred to reheat it prior to consumption. Most respondents (83.9%; 94 of 112) reheated the scrapple by pan frying for 1 to 10 min at medium to high temperature. To study pathogen behavior, slices of pork scrapple were surface inoculated with a five-strain cocktail of L. monocytogenes (ca. 2.0 log CFU/g), vacuum sealed, and stored for up to 60 days. Pathogen levels increased to 8.9, 9.5, and 9.9 log CFU/g after 44 (4 degrees C), 21 (10 degrees C), and 5 (21 degrees C) days, respectively. When slices 1.3 cm (ca. 55 g) and 1.9 cm (ca. 85 g) thick were surface inoculated with L. monocytogenes (ca. 7.0 log CFU/g) and then reheated in a skillet (191 degrees C) for 0.5 to 4 min per side or to target instantaneous internal temperatures of 48.9 to 71.1 degrees C, it was possible to achieve pathogen reductions ranging from ca. 2.2 to 6.5 log CFU/g. These data confirm that in the unlikely event of postprocessing contamination of pork scrapple by L. monocytogenes, proper reheating can appreciably reduce levels of the pathogen before consumption.

Validation of commercial processes for inactivation of Escherichia coli O157:H7, Salmonella Typhimurium, and Listeria monocytogenes on the surface of whole-muscle turkey jerky.

Three strips of turkey breast meat were separately inoculated with multistrain mixtures of Escherichia coli O157:H7, Salmonella Typhimurium, or Listeria monocytogenes and placed on the top, middle, and bottom levels of a loading rack. The strips on the rack were then loaded into a smokehouse and cooked-dried for either 2.5 or 3.5 h at 73.8 degrees C (165 degrees F) or 1.5 or 2.5 h at 82.2 degrees C (180 degrees F) with constant hickory smoking and without addition of humidity. Cooking-drying marinated turkey jerky at 73.8 degrees C (165 degrees F) or 82.2 degrees C (180 degrees F) resulted in a >or= 7.1 log(10) cfu/strip reduction of all 3 pathogens. For nonmarinated jerky strips that were inoculated with E. coli O157:H7 or L. monocytogenes and cooked-dried at 82.2 degrees C (180 degrees F), a reduction of >or= 7.4 log(10) cfu/strip was observed, whereas for strips that were inoculated with Salmonella, a reduction of >or= 6.8 log(10) cfu/strip was observed. Cooking-drying nonmarinated turkey breast strips at 73.8 degrees C (165 degrees F) for 3.5 h resulted in a reduction of ca. 7.1 to 7.6 log(10) cfu/strip for all 3 pathogens, whereas for strips that were cooked-dried for 2.5 h, a reduction of ca. 5.4 to 6.2 log(10) cfu/strip was observed. Only marinated turkey jerky that was cooked-dried for 3.5 h at 73.8 degrees C (165 degrees F) satisfied the USDA-FSIS standard of identity (moisture: protein

Task constraints mask great apes' ability to solve the trap-table task.

Researchers have investigated animals' causal knowledge with a task requiring subjects to use a tool to bring a reward within reach whilst avoiding a trap. Previous studies have suggested limitations in the ability of several species to avoid traps in tubes or tables. However, certain features may have inflated task difficulty. We tested 20 chimpanzees (Pan troglodytes), 7 orangutans (Pongo pygmaeus), 5 bonobos (Pan paniscus), and 5 gorillas (Gorilla gorilla) in the trap-table--a task in which subjects have to pull one of two rakes prepositioned behind two rewards on a flat surface. One of the rewards is in front of a trap into which it will fall. We investigated the effect of trap type, tool type, the number of available tools, and reinforcement regime on performance. We replicated previous findings showing that apes failed to choose the correct rake above chance. However, when they could instead choose where to insert a single tool, around 80% of the apes solved the trap-table task in the first trial, revealing an important effect of task constraints on their performance.

Translocation of surface-inoculated Escherichia coli O157:H7 into beef subprimals following blade tenderization.

In phase I, beef subprimals were inoculated on the lean side with ca. 0.5 to 3.5 log CFU/g of a rifampin-resistant (rifr) cocktail of Escherichia coli O157:H7 and passed once, lean side up, through a mechanical blade tenderizer. Inoculated subprimals that were not tenderized served as controls. Ten core samples were removed from each subprimal and cut into six consecutive segments: segments 1 to 4 comprised the top 4 cm and segments 5 and 6 the deepest 4 cm. Levels of E. coli O157:H7 recovered from segment 1 of control subprimals when inoculated with ca. 0.5, 1.5, 2.5, or 3.5 log CFU/g were 0.6, 1.46, 2.5, and 3.19 log CFU/g, respectively. Following tenderization, pathogen levels recovered from segment 1 inoculated with 0.5 to 3.5 log CFU/g were 0.22, 1.06, 2.04, and 2.7 log CFU/g, respectively. Levels recovered in segment 2 were 7- to 34-fold lower than levels recovered from segment 1. Next, in phase II, the translocation of ca. 4 log CFU of the pathogen per g was assessed for lean-side-inoculated subprimals passed either once (LS) or twice (LD) through the tenderizer and for fat-side-inoculated subprimals passed either once (FS) or twice (FD) through the tenderizer. Levels in segment 1 for LS, LD, FS, and FD tenderized subprimals were 3.63, 3.52, 2.85, and 3.55 log CFU/g, respectively. The levels recovered in segment 2 were 14- to 50-fold lower than levels recovered in segment 1 for LS, LD, FS, and FD subprimals. Thus, blade tenderization transfers E. coli O157:H7 primarily into the topmost 1 cm, but also into the deeper tissues of beef subprimals.

Viability of multi-strain mixtures of Listeria monocytogenes, Salmonella typhimurium, or Escherichia coli O157:H7 inoculated into the batter or onto the surface of a soudjouk-style fermented semi-dry sausage.

The fate of Listeria monocytogenes, Salmonella typhimurium, or Escherichia coli O157:H7 were separately monitored both in and on soudjouk. Fermentation and drying alone reduced numbers of L. monocytogenes by 0.07 and 0.74 log(10)CFU/g for sausages fermented to pH 5.3 and 4.8, respectively, whereas numbers of S. typhimurium and E. coli O157:H7 were reduced by 1.52 and 3.51 log(10)CFU/g and 0.03 and 1.11 log(10)CFU/g, respectively. When sausages fermented to pH 5.3 or 4.8 were stored at 4, 10, or 21 degrees C, numbers of L. monocytogenes, S. typhimurium, and E. coli O157:H7 decreased by an additional 0.08-1.80, 0.88-3.74, and 0.68-3.17 log(10)CFU/g, respectively, within 30 days. Storage for 90 days of commercially manufactured soudjouk that was sliced and then surface inoculated with L. monocytogenes, S. typhimurium, and E. coli O157:H7 generated average D-values of ca. 10.1, 7.6, and 5.9 days at 4 degrees C; 6.4, 4.3, and 2.9 days at 10 degrees C; 1.4, 0.9, and 1.6 days at 21 degrees C; and 0.9, 1.4, and 0.25 days at 30 degrees C. Overall, fermentation to pH 4.8 and storage at 21 degrees C was the most effective treatment for reducing numbers of L. monocytogenes (2.54 log(10)CFU/g reduction), S. typhimurium (> or =5.23 log(10)CFU/g reduction), and E. coli O157:H7 (3.48 log(10)CFU/g reduction). In summary, soudjouk-style sausage does not provide a favorable environment for outgrowth/survival of these three pathogens.

Spontaneous innovation of hook-bending and unbending in orangutans (Pongo abelii).

Betty the crow astonished the scientific world as she spontaneously crafted hook-tools from straight wire in order to lift a basket out of vertical tubes. Recently it was suggested that this species' solution was strongly influenced by predispositions from behavioural routines from habitual hook-tool manufacture. Nevertheless, the task became a paradigm to investigate tool innovation. Considering that young humans had surprising difficulties with the task, it was yet unclear whether the innovation of a hooked tool would be feasible to primates that lacked habitual hook making. We thus tested five captive orangutans in a hook bending and unbending task. Orangutans are habitually tool-using primates that have been reported to use but not craft hooked tools for locomotion in the wild. Two orangutans spontaneously innovated hook tools and four unbent the wire from their first trial on. Pre-experience with ready-made hooks had some effect but did not lead to continuous success. Further subjects improved the hook-design feature when the task required the subjects to bent the hook at a steeper angle. Our results indicate that the ability to represent and manufacture tools according to a current need does not require stereotyped behavioural routines, but can indeed arise innovatively. Furthermore, the present study shows that the capacity for hook tool innovation is not limited to large brained birds within non-human animals.

Prevalence, types, and geographical distribution of Listeria monocytogenes from a survey of retail Queso Fresco and associated cheese processing plants and dairy farms in Sonora, Mexico.

In the first part of this study, samples were collected from farms, cheese processing plants (CPPs), and retail markets located in various geographical areas of Sonora, Mexico, over a 12-month period during the summer of 2004 and winter of 2005. Four (all Queso Fresco [QF] from retail markets) of 349 total samples tested positive for Listeria monocytogenes (Lm). Of these four positive samples, three were collected in the northern region and one in the southern region of Sonora. Additionally, two were collected during the winter months, and two were collected during the summer months. For the second part of the study, a total of 39 samples from a farm, a CPP, and retail markets were collected and processed according to a combination of the Norma Oficial Mexicana NOM-143-SSA1-1995.10 method (NOM) and the U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual method, and 27 samples from these same locations were collected and processed according to the U.S. Department of Agriculture Food Safety and Inspection Service method (USDA-FSIS). The NOM-FDA method recovered the pathogen from 6 (15%) of 39 samples (one cheese and five product contact surfaces), while the USDA-FSIS method recovered the pathogen from 5 (18.5%) of 27 samples (all product contact surfaces). In addition, the 40 isolates recovered from the 15 total samples that tested positive for Lm grouped into five distinct pulsotypes that were ca. 60% related, as determined by pulsed-field gel electrophoresis analysis. The results of this study confirmed a 3.4% prevalence of Lm in QF collected from retail markets located in Sonora and no appreciable difference in the effectiveness of either the NOM-FDA or USDA-FSIS method to recover the pathogen from cheese or environmental samples.

Social manipulation in nonhuman primates: Cognitive and motivational determinants.

Social interactions are the result of individuals' cooperative and competitive tendencies expressed over an extended period of time. Although social manipulation, i.e., using another individual to achieve one's own goals, is a crucial aspect of social interactions, there has been no comprehensive attempt to differentiate its various types and to map its cognitive and motivational determinants. For this purpose, we survey in this article the experimental literature on social interactions in nonhuman primates. We take social manipulation, illustrated by a case study with orangutans (Pongo abelii), as our starting point and move in two directions. First, we will focus on a flexibility/sociality axis that includes technical problem solving, social tool-use and communication. Second, we will focus on a motivational/prosociality axis that includes exploitation, cooperation, and helping. Combined, the two axes offer a way to capture a broad range of social interactions performed by human and nonhuman primates.

Viability of Listeria monocytogenes on commercially-prepared hams surface treated with acidic calcium sulfate and lauric arginate and stored at 4°C.

We demonstrated the effectiveness of delivering an antimicrobial purge/fluid into shrink-wrap bags immediately prior to introducing the product and vacuum sealing, namely the "Sprayed Lethality In Container" (SLIC™) intervention delivery method. The pathogen was Listeria monocytogenes, the antimicrobials were acidic calcium sulfate (ACS; calcium sulfate plus lactic acid; 1:1 or 1:2 in dH(2)O) and lauric arginate (LAE; Ethyl-N-dodecanoyl-l-arginate hydrochloride; 5% or 10% in dH(2)O), and the product was commercially prepared "table brown" ham (ca. 3 pounds each). Hams were surface inoculated with a five-strain cocktail of L. monocytogenes (ca. 7.0 log(10) CFU per ham), added to shrink-wrap bags that already contained ACS or LAE, vacuum-sealed, and stored at 4°C for 24h. Pathogen levels decreased by 1.2, 1.6, 2.4, and 3.1 log(10) CFU/ham and 0.7, 1.6, 2.2, and 2.6 log(10) CFU/ham in samples treated with 2, 4, 6, and 8mL of a 1:1 and 1:2 solution of ACS, respectively. In samples treated with 2, 4, 6, and 8mL of a 5% solution of LAE, pathogen levels decreased by 3.3, 6.5, 5.6, and 6.5 log(10) CFU/ham, whereas when treated with a 10% solution of LAE pathogen levels decreased ca. 6.5 log(10) CFU/ham for all application volumes tested. The efficacy of ACS and LAE were further evaluated in shelf-life studies wherein hams were surface inoculated with either ca. 3.0 or 7.0 log(10) CFU of L. monocytogenes, added to shrink-wrap bags that contained 0, 4, 6, or 8mL of either a 1:2 solution of ACS or a 5% solution of LAE, vacuum-sealed, and stored at 4°C for 60 days. For hams inoculated with 7.0 log(10) CFU, L. monocytogenes levels decreased by ca.1.2, 1.5, and 2.0 log(10) CFU/ham and 5.1, 5.4, and 5.5 log(10) CFU/ham within 24h at 4°C in samples treated with 4, 6, and 8mL of a 1:2 solution of ACS and a 5% solution of LAE, respectively, compared to control hams that were not treated with either antimicrobial. Thereafter, pathogen levels remained relatively unchanged (±1.0 log(10) CFU/ham ) after 60 days at 4°C in hams treated with 4, 6, and 8mL of a 1:2 solution of ACS and increased by ca. 2.0-5.0 log(10) CFU/ham in samples treated with 4, 6, and 8mL of a 5% solution of LAE. For hams inoculated with 3.0 log(10) CFU, L. monocytogenes levels decreased by 1.3, 1.9, and 1.8 log(10) CFU/ham within 24h at 4°C in samples treated with 4, 6, and 8mL of a 1:2 solution of ACS, respectively, compared to control hams that were not treated. Likewise, levels of the pathogen were reduced to below the limit of detection (i.e., 1.48 log(10) CFU/ham) in the presence of 4, 6, and 8mL of a 5% solution of LAE within 24h at 4°C. After 60 days at 4°C, pathogen levels remained relatively unchanged (±0.3 log(10) CFU/ham) in hams treated with 4, 6, and 8mL of a 1:2 solution of ACS. However, levels of L. monocytogenes increased by ca. 2.0 log(10) CFU/ham in samples treated with 4 and 6mL of a 5% LAE solution within 60 days but remained below the detection limit on samples treated with 8mL of this antimicrobial. These data confirmed that application via SLIC™ of both ACS and LAE, at the concentrations and volumes used in this study, appreciably reduced levels of L. monocytogenes on the surface of hams within 24h at 4°C and showed potential for controlling outgrowth of the pathogen over 60 days of refrigerated storage.

Development and application of a quantitative, specific assay for Cryptosporidium parvum oocyst detection in high-turbidity environmental water samples.

Chlorine-resistant Cryptosporidium parvum oocysts in drinking water play an important role in the epidemiology of cryptosporidiosis. Current methods of detecting these organisms in water are insensitive, labor-intensive, highly subjective, and severely limited by sample turbidity. We describe here an alternative technique utilizing electrochemiluminescence (ECL) technology for detecting C. parvum oocysts in environmental water samples. This method is quantitative, reproducible, and requires only minimal sample processing. Currently, the ECL assay can detect as few as one oocyst in one milliliter of concentrated test sample with sample turbidity of up to 10,000 nephelometric turbidity units. Water and sewer samples collected during a cryptosporidiosis outbreak were tested by ECL assay. Cryptosporidium parvum oocysts were found in the source water at the time of outbreak, and a sharply decreasing level of oocysts in sewer samples was observed over a three-month period following the outbreak.

Permanent percutaneous antegrade ureteral stent placement without transurethral assistance.

A simple, one-step, permanent, percutaneous, antegrade insertion of a ureteral stent is described, utilizing a double, pigtail catheter. No transurethral assistance is necessary. The advantages of this simplified technique are presented, and the necessary prerequisites for its application are discussed.

Object permanence in orangutans (Pongo pygmaeus), chimpanzees (Pan troglodytes), and children (Homo sapiens).

Juvenile and adult orangutans (n = 5; Pongo pygmaeus), chimpanzees (n = 7; Pan troglodytes), and 19- and 26-month-old children (n = 24; Homo sapiens) received visible and invisible displacements. Three containers were presented forming a straight line, and a small box was used to displace a reward under them. Subjects received 3 types of displacement: single (the box visited 1 container), double adjacent (the box visited 2 contiguous containers), and double nonadjacent (the box visited 2 noncontiguous containers). All species performed at comparable levels, solving all problems except the invisible nonadjacent displacements. Visible displacements were easier than invisible, and single were easier than double displacements. In a 2nd experiment, subjects saw the baiting of either 2 adjacent or 2 nonadjacent containers with no displacements. All species selected the empty container more often when the baited containers were nonadjacent than when they were adjacent. It is hypothesized that a response bias and inhibition problem were responsible for the poor performance in nonadjacent displacements.