Pathological Changes and Immunity Associated with Experimental Eimeria vermiformis Infections in Mus musculus1

ABSTRACT. Pathological changes and immunity induced by Eimeria vermiformis (Ernst, Chobotar & Hammond, 1971) were studied in outbred Swiss mice inoculated with 5000, 10,000, 20,000, or 40,000 oocysts. Cross immunity to E. ferrisi was also studied. In the case of E. vermiformis, mortality was dose dependent; most deaths were observed in the intermediate-dose groups. Most deaths also correlated with peak oocyst output. Histopathologic changes consisted of an early neutrophil and mononuclear cell infiltration in the small intestine. Later, villus atrophy and crypt hyperplasia caused a decrease in the villus-crypt ratio. During the acute phase (8-10 days after inoculation), villus tips were eroded and parasites with necrotic debris filled the cryptal and intestinal lumina. Vacuolar changes were observed in epithelial cells of the small intestine. Neither parasites nor significant pathological changes were observed in extra-intestinal organs. Mice were totally immune to reinfection with E. vermiformis 30 and 105 days after inoculation. Cross immunity was not observed between E. vermiformis and E. ferrisi.     

The loss of submerged plants with eutrophication III. Potential role of organochlorine pesticides: a palaeoecological study

SUMMARY. 1 Mechanisms which might have caused a switch from submerged plant dominance to phytoplankton dominance in a series of shallow lakes, the Norfolk Broads, during the 1950s and 1960s, are reviewed. It is argued that a likely mechanism was a poisoning of the community of Cladocera which graze on algae and are associated with the plants. This allowed phytoplankton to take advantage of the increased nutrient loadings and to increase. The 1950s and 1960s were periods of liberal organochlorine pesticide use. Cladocera are particularly susceptible to organochlorine toxicity.
2. Sediment cores were taken from Hoveton Great Broad, in which the switch to phytoplankton has occurred, and from two Broads (Upton and Martham South Broads) in which submerged plants are still dominant. Analyses were made for cladoceran remains, diatoms and molluscs. Cross dating with previously taken dated cores allowed time-scales to be applied.
3. In Hoveton Great Broad, a switch from clear-water-associated chydorids to turbid-water forms was found to coincide with the loss of aquatic plants in the 1950s. No Daphnia remains were found. In the other two Broads, clear-water chydorids, mostly plant-associated, were found throughout the cores.
4. Residues of dieldrin (HEOD), DDD and TDE were found in the Hoveton Great Broad cores, with the DDT derivatives particularly associated with the end of the phase of submerged plant dominance and the beginning of that of phytoplankton dominance. Bosmina remains became more abundant after this point. Pesticide residues were scarce in the cores from the other two Broads and did not form any particular pattern. Residues of polychlorinated biphenyls were widespread in all cores.
5. Calculation of DDT concentration in the water at the time the sediments with greatest concentrations of residue were laid down suggests that concentrations above typical LC₅₀ values for Daphnia species could have been present.     

Puma and Human Spatial and Temporal Use of a Popular California State Park

Abstract: Because of increasing concerns about puma (Puma concolor) attacks on people and the desire to minimize dangerous puma-human encounters while conserving puma populations, we examined spatial and temporal relationships between pumas and people that used Cuyamaca Rancho State Park (CRSP), California, USA. From 2001 to 2003, we studied 10 adult pumas outfitted with Global Positioning System collars. Although number of visitors to CRSP was increasing, no dangerous puma-human encounters were reported during our study. Male and female pumas typically moved short distances during the day (mean of means of individual hourly movements = 168 m and 131 m each hr, respectively) and moved the most at night (mean of means = 690 m and 390 m each hr, respectively). Of 10 pumas, 9 were least active during the day and most active during the evening or at night. In contrast, most visitor use of trails (x̄ = 85%) occurred during the day. Based on puma and human activity patterns, risk of a puma-human encounter was greatest during the evening. Puma prey caches were randomly distributed in relation to trails and park facilities; however, 8 of 33 caches were still within 100 m of a trail and 2 were within 300 m of a facility. Individual puma behavior relative to human activity areas was variable. Some pumas appeared to temporally avoid human activity areas; others used the park randomly in relation to human activity areas; none appeared to be attracted to human activity areas. Pumas that did not show detectable responses to human activity may have been exhibiting some level of habituation; if so, this level of habituation did not result in puma-human conflicts. When human activity peaked during the day, adult male and female pumas were within 100 m of a trail an average of 9% and 19% of the time they were located in the park, respectively. Thus, there were opportunities for puma-human encounters. Management personnel can take a proactive approach to deal with puma-human interactions through education and protocols that help to minimize probability of conflicts; this may provide the best chance for a continued puma presence in habitat used by pumas and people.     

Patchiness, aggregation, and the coexistence of competitors for ephemeral resources

Abstract. 1. A laboratory experiment was conducted to determine the outcome of competition between two species of carrion-breeding Diptera for food at two levels of resource patchiness.
2. Adults of Fannia howardi Malloch (Muscidae) and Megaselia scalaris Loew (Phoridae) were released into a large population cage and were given access to three 2g sections of pork kidney in one treatment (low patchiness) and to twelve 0.5g sections in the other (high patchiness).
3. Increasing the patchiness of the resource resulted in reduced overlap in the distribution of the two species, and therefore less interspecific competition. However, this did not result in improved survival of the poorer competitor, F.howardi. Both species aggregated their eggs at high patchiness, and therefore suffered from increased levels of intraspecific competition.
4. The experiment shows that increasing patchiness in this way could lead to prolonged coexistence, as has been predicted in other studies.     

Evaluation of an Aerial Survey to Estimate Abundance of Wintering Ducks in Mississippi

Abstract: Researchers have successfully designed aerial surveys that provided precise estimates of wintering populations of ducks over large physiographic regions, yet few conservation agencies have adopted these probability-based sampling designs for their surveys. We designed and evaluated an aerial survey to estimate abundance of wintering mallards (Anas platyrhynchos), dabbling ducks (tribe Anatini) other than mallards, diving ducks (tribes Aythini, Mergini, and Oxyurini), and total ducks in western Mississippi, USA. We used design-based sampling of fixed width transects to estimate population indices (Ǐ), and we used model-based methods to correct population indices for visibility bias and estimate population abundance (Ň) for 14 surveys during winters 2002–2004. Correcting for bias increased estimates of mallards, other dabbling ducks, and diving ducks by an average of 40–48% among all surveys and contributed 48–61% of the estimated variance of Ň. However, mean-squared errors were consistently less for Ň than Ǐ. Estimates of Ň met our goals for precision (CV ≤ 15%) in 7 of 14 surveys for mallards, 5 surveys for other dabbling ducks, no surveys for diving ducks, and 10 surveys for total ducks. Generally, we estimated more mallards and other dabbling ducks in mid- and late winter (Jan-Feb) than early winter (Nov-Dec) and determined that population indices from the late 1980s were nearly 3 times greater than those from our study. We developed a method to display relative densities of ducks spatially as an additional application of survey data. Our study advanced methods of estimating abundance of wintering waterfowl, and we recommend this design for continued monitoring of wintering ducks in western Mississippi and similar physiographic regions.     

Coral assemblages, biofacies, and ecological zones in the mid-Holocene reef deDosits of the Enriquillo Valley, Dominican Republic

Stemann, T. A. & Johnson, K. G. 1992 07 15: Coral assemblages, biofacies. and ecological zones in the mid-Holocene reef deposits of the Enriquillo Valley, Dominican Republic. A large, subaerially exposed mid-Holocene reef in the Enriquillo Valley (southwest Dominican Republic) provides an excellent opportunity to examine the relationship between reefal ecology and reefal deposits. Coral species richness and diversity in the Enriquillo reef are comparable to that found in the recent of the Caribbean, and ecological zonation comprised of a shallow-water branching coral zone and a deeper water mixed-coral zone is apparent. Similar zonation and diversity patterns have been recognized on living Caribbcan reefs with moderate wave exposure. Three statistically discrete biopdcies can be discriminated in the Enriquillo deposits using quadrat point-counting techniques commonly used to census modern reefs. They include a facies dominated by Acropora cervicornis, a low diversity assemblage with abundant, large colonies of Siderastrea siderea and Stephanocoenia intersepta, and a higher diversity assembbdge composed of various taxa including Montastraea spp., Colpophyllia spp., and Agaricia spp. Each facies can be recognized at scales of 1–3 m², though in some cases they extend for more than 20 m². In general, the A. cervicornis facies is spatially segregated from the other two biofacies. although neither the shallow nor the deep-water ecological zone is comprised of a single reef biofacies. Rather, the biofacies described here appear to represent distinct micro-environments resulting from ecological variation at a subzonal scale. Micro-environments of similar scale are most likely preserved in other reef deposits. Recognition of these subzonal biofacies may have important consequences for the stratigraphical and paleoccological interpretation of fossil reefs. Corals, biofacies, reef zonation, coral communities, fossil reefs.     

Validity of the bereavement exclusion criterion for the diagnosis of major depressive episode

Since the publication of DSM-III in 1980, the official position of American psychiatry has been that the presence of bereavement is an exclusion criterion for the diagnosis of a major depressive episode (MDE). However, the empirical validity of this exclusion has not been well established. As DSM-V is now being planned, it is timely to reexamine the bereavement exclusion, particularly in the light of new evidence since the last reviews of this subject. This paper evaluates the relative validity of two competing hypotheses: 1) the bereavement exclusion for the diagnosis of MDE is not valid because, using validating criteria, bereavement related depression (BRD) within the first two months after the death of a loved one resembles non-bereavement related depression (SMD); 2) the bereavement exclusion for the diagnosis of MDD is valid because, using validating criteria, BRD within the first two months after the death of a loved one does not resemble SMD. The prevailing evidence more strongly supports Hypothesis 1 than Hypothesis 2. Thus, the bereavement exclusion for the diagnosis of MDE may no longer be justified.     

A Field Evaluation of Distance Measurement Error in Auditory Avian Point Count Surveys

ABSTRACT Detection distance is an important and common auxiliary variable measured during avian point count surveys. Distance data are used to determine the area sampled and to model the detection process using distance sampling theory. In densely forested habitats, visual detections of birds are rare, and most estimates of detection distance are based on auditory cues. Distance sampling theory assumes detection distances are measured accurately, but empirical validation of this assumption for auditory detections is lacking. We used a song playback system to simulate avian point counts with known distances in a forested habitat to determine the error structure of distance estimates based on auditory detections. We conducted field evaluations with 6 experienced observers both before and after distance estimation training. We conducted additional studies to determine the effect of height and speaker orientation (toward or away from observers) on distance estimation error. Distance estimation errors for all evaluations were substantial, although training reduced errors and bias in distance estimates by approximately 15%. Measurement errors showed a nonlinear relationship to distance. Our results suggest observers were not able to differentiate distances beyond 65 m. The height from which we played songs had no effect on distance estimation errors in this habitat. The orientation of the song source did have a large effect on distance estimation errors; observers generally doubled their distance estimates for songs played away from them compared with distance estimates for songs played directly toward them. These findings, which we based on realistic field conditions, suggest measures of uncertainty in distance estimates to auditory detections are substantially higher than assumed by most researchers. This means aural point count estimates of avian abundance based on distance methods deserve careful scrutiny because they are likely biased.