Pyrethroid insecticides derived from 2,2′ -bridged biphenyl-3-ylmethanols

The addition of a hydrocarbon bridge between the 2- and 2′-positions in biphenyl constrains the twist angle between the two phenyl rings to fairly small limits. It has been found that the biological activity of a series of pyrethroid esters, of hydrocarbon bridged biphenyl-3-ylmethanols and of heterocyclic hydrocarbonbridged biphenyl analogues, changes with the length of the bridge. The optimum activity and the maximum biological activity spectrum were found for the esters of three-carbon bridged alcohols. The relationship of the activity to the twist angle for these bridged esters was compared with the activity and spectrum of a series of biphenyl and heterocyclic biphenyl analogues previously reported. A parallel exists between the two series. The optimum twist angle between the aromatic rings of the alcohols, in both the bridged and free rotating analogues, is around 50°. Pyrethroid esters showing the highest activity were produced from 6, 7-dihydro-5H-dibenzo-[a,c]cyclohepten-4-ylmethanol. The biological activity of a series of pyrethroid esters of this alcohol is also reported.     

Chemoprophylaxis of cryptosporidiosis in chickens, using halofuginone, salinomycin, lasalocid, or monensin

Chemoprophylaxis of Cryptosporidium baileyi infections was attempted by feeding 4 groups of chicks diets containing 3 mg of halofuginone/kg of feed, 60 mg of salinomycin/kg, 75 mg of lasalocid/kg, or 110 mg of monensin/kg. Rations were fed 5 days before oral or intratracheal inoculation with oocysts and were continued for 20 days. None of the drugs prevented C baileyi infections. Clinical signs of respiratory tract disease and gross lesions of airsacculitis were observed in intratracheally inoculated birds in all treatment groups and nonmedicated controls. Orally inoculated birds did not develop clinical signs of infection. Pathogenic bacteria were not isolated from the respiratory tract systems of any chicks. Halofuginone delayed the establishment of infections of the bursa of Fabricius and cloaca, but not of the trachea.     

A serological study of Babesia caballi and Theileria equi in Thoroughbreds in Trinidad

Ninety-three (93) horses were investigated for serum antibodies to Theileria equi (T. equi) and Babesia caballi (B. caballi) using the immunofluorescent antibody test (IFAT). Seventy-seven (82.8%) horses were seropositive; 31 (33.3%) were positive to T. equi compared to 64 (68.8%) to B. caballi while 18 (19.4%) horses were seropositive to both parasites. No significant differences in antibody frequencies among females and males for either T. equi or B. caballi were noted. Differences in seropositivity to B. caballi among age groups were not significant. Antibodies to T. equi were more frequent than to B.caballi in the age group 5 years and over than in the 1-2 and 2-4 years age groups (p<0.05). Unlike T. equi antibodies, B. caballi antibodies in horses in the county of Caroni were significantly less frequent when compared to other counties (p<0.05). Of 18 (19.4%) clinically ill horses, seven (42.9%) had clinicopathological evidence of anemia. Only one-third (6 of 18) horses were positive for the parasite on Wright-Giemsa stained blood smears and anemia was present in only 2. We report here that B. caballi and not T. equi may be the more common agent of piroplasmosis in Trinidad.     

Alpha and kappa electroencephalogram activity in eyeless subjects

Several reports have cast doubt on the cerebral origin of alpha and kappa electroencephalogram activity by charging that they are artifacts related to eye activity. Data are cited which eliminate the corneoretinal potential of the eyeball, tremor of the extraocular muscles, eye position, accommodation, and eye flutter as sources of alpha and kappa electroencephalogram activity. A subject with both eyes removed showed normal alpha and kappa electroencephalogram activity. Marked left-right differences in alpha activity were not found in one-eyed subjects whose eyes and extraocular muscles were completely removed on one side.     

Delayed compensation for missing keystone species by colonization

Because individual species can play key roles, the loss of species through extinction or their gain through colonization can cause major changes in ecosystems. For almost 20 years after kangaroo rats were experimentally removed from a Chihuahuan desert ecosystem in the United States, other rodent species were unable to compensate and use the available resources. This changed abruptly in 1995, when an alien species of pocket mouse colonized the ecosystem, used most of the available resources, and compensated almost completely for the missing kangaroo rats. These results demonstrate the importance of individual species and of colonization and extinction events in the structure and dynamics of ecosystems.     

Shear press determinations of the raw product as a possible tool for quality measurement of potatoes

Texture determinations were made with a Food Technology Corporation shear press on Russet Burbank and Norgold tubers as they grew and developed from July 1 until October 15, 1970. Shear force reading increased as Russet Burbank tubers grew and increased in dry matter content. However, no increase in shear force was obtained with growth and development of the Norgold variety. Tubers harvested in the Fall were placed in 48 F storage and separated into specific gravity groups in increments of 0.005 with a brine solution. As specific gravity of the Russet Burbank variety increased, shear force readings also increased. Shear force of the Norgold Russet did not change with specific gravity changes. A very high correlation was obtained between raw shear force readings of specific gravity groups (Russet Burbank) and processed frozen french, fries of the same lots which were finish fried and shear force readings made within 3 minutes after removal from the fryer. Again, the correlation between raw shear force readings and finish fry readings of Norgold Russet was very poor, although the finish fry product readings increased as specific gravity increased.     

Biology of Larks (Aves: Alaudidae) in the Central Namib Desert

1. The biology of six species of larks in the Namib Desert near Walvis Bay, South West Africa, was studied in 1964, 1965 and 1966.

2. All species reproduced following rainfall in summer and autumn months, with the appearance of green grass and abundant insects on which the birds fed.

3. The primarily insectivorous species, Certhilauda albofasciata, shows no seasonality in moulting and testicular development, and reproduces whenever local rainfall results in favourable feeding and nesting circumstances, while the primarily granivorous Spizoeorys starki and Eremopterix verticalis have markedly seasonal testicular and moulting cycles timed so that reproduction occurs only during the late summer and autumn months. Ammomanes grayi is intermediate in food habits and in timing of moulting and reproduction, and C. albescens and Mirafra naevia may also be intermediate in this respect.

4. S. starki and E. verticalis are the only larks that normally drink, but flocks of both species were observed that were independent of drinking water.

5. Larks avoid heat stress during daytime by keeping to the shade of stones, tufts of vegetation and mouths of rodent burrows; and nests are nearly always placed on the shady side of a stone' or tuft of grass.

6. It is suggested that larks may be successful desert occupants because they have not become highly specialized and therefore can tolerate rapidly and severely changing environ-mental conditions associated with drought and irregular rainfall.