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1.
A new technique has been developed for estimating age in rhesus macaques (Macaca mulatta) that is based on mandibular measurements and has several advantages over presently available techniques. First, the new technique is relatively quick and inexpensive because a single measurement or radiograph suffices to produce an age estimate. Second, mandibular growth represents a more continuous phenomenon than either epiphyseal union or dental eruption; therefore, age estimates may be made throughout the period of growth without significant gaps in the process. Finally, the new technique may be used on incomplete or even fragmentary skeletal material because it requires that only a portion of the mandible be preserved. The new technique produces age estimates with a prediction error of ±5.08 months in males and ±7.29 months in females. These errors are only slightly higher than those found previously for dental eruption or epiphyseal union data.  相似文献   
2.
Fort Greely, Alaska has an extensive complex of weapon training and testing areas located on lands withdrawn from the public domain under the Military Lands Withdrawal Act (PL106-65). The Army has pledged to implement a program to identify possible munitions contamination. Because of the large size (344,165,000 m2) of the high hazard impact areas, characterization of these constituents will be difficult. We used an authoritative sampling design to find locations most likely to contain explosives-residues on three impact areas. We focused our sampling on surface soils and collected multi-increment and discrete samples at locations of known firing events and from areas on the range that had craters, pieces of munitions, targets, or a designation as a firing point. In the two impact areas used primarily by the Army, RDX was the most frequently detected explosive. In the impact area that was also used by the Air Force, TNT was the most frequently detected explosive. Where detected, the explosives concentrations generally were low (<0.05 mg/kg) except in soils near low-order detonations, where the explosive-filler was in contact with the soil surface. These low-order detonations potentially can serve as localized sources for groundwater contamination if positioned in recharge areas.  相似文献   
3.
The biosynthesis of glyantrypine from radiolabelled amino acid precursors has been shown experimentally to involve anthranilic acid, tryptophan and glycine. Low values for percentage incorporation of radiolabel into glyantrypine were partly influenced by a complex array of other novel alkaloids shown by the radiolabelling experiments to be related to glyantrypine. Interpretation of radiolabel incorporation from [14C-carboxyl]-anthranilic acid into microbial metabolites seen to contain an anthranilyl moiety in various biosynthetic arrangements is discussed. The possibility of diversion of anthranilic acid from the kynurenine pathway to glyantrypine biosynthesis is recognised.  相似文献   
4.
Plasmid-based excision assays performed in embryos of two non-drosophilid species using the mariner transposable element from Drosophila mauritiana resulted in empty excision sites identical to those observed after the excision of mariner from D. mauritiana chromosomes. In the presence of the autonomous mariner element Mos1, excision products were recovered from D. melanogaster, D. mauritiana and the blowfly Lucilia cuprina. When a hsp82 heat shock promoter-Mos1 construct was used to supply mariner transposase, excision products were also recovered from the Queensland fruitfly Bactrocera tryoni. Analysis of DNA sequences at empty excision sites led us to hypothesise that the mariner excision/repair process involves the formation of a heteroduplex at the excision breakpoint. The success of these assays suggests that they will provide a valuable tool for assessing the ability of mariner and mariner-like elements to function in non-drosophilid insects and for investigating the basic mechanisms of mariner excision and repair.  相似文献   
5.
The vegetation of a snow bed has been described by a pin-point method and a modified Raunkiær frequency analysis. The thawing of the snow has been followed and some soil properties have been investigated. It is concluded that the composition of the vegetation in the snow bed is influenced mainly by the duration of the growth period, but locally the density and the species composition are determined by the downward flow of the melt water.  相似文献   
6.
The activation of uterine smooth muscle adenylate cyclase was studied by pretreating the particulate form of the enzyme with the GTP analog guanyl-5′-yl imidodiphosphate (Gpp(NH)p). Pretreatment with Gpp(NH)p left the enzyme in an irreversibly activated state which survived subsequent washing in guanyl nucleotide-free buffer. Activation under these conditions was multiphasic with rapid and slow components. At 23 °C slow activation proceeded at about 110th the rate of rapid activation. The onset of the slow phase took longer at lower temperatures. Routine adenylate cyclase assay conditions (conversion of [32P]ATP to cyclic [32P]AMP) carried out without pretreatment probably characterized the rapidly activated component. The simplest kinetic model suggests not only the generally accepted two-step association reaction, but also implies the existence of more than one enzyme form, each of which is characterized by a separate activation rate. The complex kinetics of activation might be explained by a heterogeneous mixture of unassociated and preassociated nucleotide binding and catalytic subunits.  相似文献   
7.
T-cell receptor (Tcr) chains are classified into four subgroups (I, II, III, and miscellaneous) based on the amino acid residues at positions 61 and 62. Subgroup I has Gly Phe at these positions, subgroup II has Arg Phe, subgroup III has Arg Leu, and subgroup miscellaneous has several other combinations. Variability plots for subgroups I, II, and III sequences show higher values around positions 93–103, 105, 108, 111, 113, and 115, suggesting that these positions may interact with the processed antigen molecules. Smaller peaks are present at various other regions which may bind the major histocompatibility complex class I or II molecules. The patterns of variability within one subgroup are similar for all species, for human alone, and for mouse alone. These subgroup patterns appear much less complicated than patterns for sequences in all subgroups taken together, implying that subgroups may be related to Tcr functions. Among 83 mouse chains, 15 are from cytotoxic cells and 40 from helper cells. Of the 15 from cytotoxic cells, 11, 2, 0, and 2 are in subgroups I, II, III, and miscellaneous; and of the 40 from helper cells, 9, 16, 12, ans 3 are in subgroups I, II, III, and miscellaneous, respectively. Thus, a correlation between sequence and function of Tcr chains seems possible. Address correspondence and offprint requests to: M. Schiffer.  相似文献   
8.
While responding to a question on medical errors in an in-depth interview, a physician told a story about a medical error. The story revealed his silent involvement in the evolution of the error. His response is presented as a text requiring interpretation. Fine details of his manner of speaking are displayed in order to disclose what he said and what it meant. In interpreting the text, phenomenological and sociolinguistic methods are used.  相似文献   
9.
Identifying inbreeding depression early in small and declining populations is essential for management and conservation decisions. Correlations between heterozygosity and fitness (HFCs) provide a way to identify inbreeding depression without prior knowledge of kinship among individuals. In Northern Quebec and Labrador, the size of two herds of migratory caribou (Rivière‐George, RG and Rivière‐aux‐Feuilles, RAF) has declined by one to two orders of magnitude in the last three decades. This raises the question of a possible increase in inbreeding depression originating from, and possibly contributing to, the demographic decline in those populations. Here, we tested for the association of genomic inbreeding indices (estimated with 22,073 SNPs) with body mass and survival in 400 caribou sampled in RG and RAF herds between 1996 and 2016. We found no association of individual heterozygosity or inbreeding coefficient with body mass or annual survival. Furthermore, those genomic inbreeding indices remained stable over the period monitored. These results suggest that the rapid and intense demographic decline of the herds did not cause inbreeding depression in those populations. Although we found no evidence for HFCs, if demographic decline continues, it is possible that such inbreeding depression would be triggered.  相似文献   
10.
Acquisition of passive immunity by endocytosis of intact immunoglobulins (Ig) from colostrum is critical for prevention of intestinal and systemic diseases in neonatal mammals. We compared proteome patterns of healthy and inflamed gut tissues from pre-term piglets to investigate the effect of inflammation on acquisition of passive immunity. A clear difference in the two-dimensional gel electrophoresis protein patterns between healthy and inflamed intestinal tissues was observed, suggesting that inflamed tissues failed to absorb and transfer Ig from colostrum to epithelial cells. We have mapped and identified the Ig proteins that are taken up by healthy intestinal tissues, and found that isoforms of the IgA and IgG heavy chain and Ig kappa and lambda light chains were internalized. Our results indicate that colostrum protein uptake in the porcine gut is a selective process that is obstructed in inflamed pre-term gut.  相似文献   
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