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In order to improve our understanding of the interior structure of Saturn's small moon Enceladus, we reanalyze radiometric tracking and onboard imaging data acquired by the Cassini spacecraft during close encounters with the moon. We compute the global shape, gravity field, and rotational parameters of Enceladus in a reference frame consistent with the International Astronomical Union's definition, where the center of the Salih crater is located at −5° East longitude. We recover a quadrupole gravity field with J3and a forced libration amplitude of 0.091° ± 0.009° (3‐σ). We also compute a global shape model using a stereo‐photoclinometry technique with a global resolution of 500 m, although some local maps have higher resolutions ranging from 25 to 100 m. While our overall results are generally consistent with previous studies, we infer a thicker 27–33 km mean ice shell, a thinner 21–26 km mean ocean thickness, and a mean core density range of 2,270–2,330 kg/m3. Geodetic data, such as shape, gravity, and rotation, provide important constraints for probing a planetary body's interior structure. We analyze radiometric tracking and onboard imaging data acquired during close encounters of Enceladus by the Cassini spacecraft to compute geodetic products including topographic and gravitational fields in a common reference frame. The recovered Enceladus topography has a global resolution of 500 m, with some local regions having 25–100 m resolution. Our study suggests that Enceladus has a 27–33 km mean ice shell thickness, a 21–26 km mean ocean thickness, and a mean core density range of 2,270–2,330 kg/m3. A full quadrupole gravity field with J3and the forced libration amplitude of 0.091° ± 0.009° are recoveredA 500‐m resolution global topography model was computed, with some local regions having 25−100 m resolutionThe results suggest that Enceladus has a 27–33 km mean ice shell thickness, a 21–26 km ocean thickness, and a mean core density range of 2,270–2,330 kg/m3 A full quadrupole gravity field with J3and the forced libration amplitude of 0.091° ± 0.009° are recovered A 500‐m resolution global topography model was computed, with some local regions having 25−100 m resolution The results suggest that Enceladus has a 27–33 km mean ice shell thickness, a 21–26 km ocean thickness, and a mean core density range of 2,270–2,330 kg/m3

This article presents the results of a fit of a numerically integrated orbit for the Saturnian satellite Phoebe to Earthbased astrometric observations (from 1904 to 1996) and imaging data acquired by the Voyager 2 spacecraft during its encounter with Saturn. The primary results are the epoch state vector for the integration and a set of mean orbital elements which approximately represent the orbit. An assessment of the quality of the fit and the accuracy of the orbit is also provided.

One of the most scrutinized contemporary techniques for geospatial data collection and production is crowdsourcing. This inverts the traditional top-down geospatial data production and distribution methods by emphasizing on the participation of the end user or community. The technique has been shown to be particularly useful in the domain of accessibility mapping, where it can augment traditional mapping methods and systems by providing information about transitory obstacles in the built environment. This research paper presents details of techniques and applications of crowdsourcing and related methods for improving the presence of transitory obstacles in accessibility mapping systems. The obstacles are very difficult to incorporate with any other traditional mapping workflow, since they typically appear in an unplanned manner and disappear just as quickly. Nevertheless, these obstacles present a major impediment to navigating an unfamiliar environment. Fortunately, these obstacles can be reported, defined, and captured through a variety of crowdsourcing techniques, including gazetteer-based geoparsing and active social media harvesting, and then referenced in a crowdsourced mapping system. These techniques are presented, along with context from research in tactile cartography and geo-enabled accessibility systems.

A map exploration and representation exercise was conducted with participants who were totally blind. Representations of maritime environments were presented either with a tactile map or with a digital haptic virtual map. We assessed the knowledge of spatial configurations using a triangulation technique. The results revealed that both types of map learning were equivalent.

Highly accurate astrometric positions of 14 of Saturn's satellites have been obtained from 444 Hubble Space Telescopeimages taken with the Wide Field Planetary Camera 2 (WFPC2) between 1996 and 2005. In all, 1036 satellite positions were measured in Planetary Camera (PC) frames, with a typical uncertainty of ?PC= 0.?014 (80 km at Saturn), and 1403 positions from Wide Field (WF) frames, with ?WF= 0.?020 (120 km at Saturn). A key part of the reduction involved the application of an improved WFPC2 distortion-correction scheme (Anderson & King) and precise determination of the relative positions of the PC and WF chips, which varied substantially over the full course of the observation period. The time span covered by the observations is more than twice the nominal duration of the Cassinimission and thus provides an important baseline of measurements that is particularly important for studying time-variable phenomena such as the orbital exchange of Janus and Epimetheus and the chaotic interactions of Prometheus and Pandora. These results have been incorporated into ephemerides that are being used for planning and analysis of Cassinisatellite and ring observations.

Communicating spatial information to the blind and visually impaired using maps and graphics presents many difficulties. Past research has offered advice to cartographers on topics such as tactile areal, point, and line symbolization; on perceptual problems related to dense linear features on tactile maps; and on the relationship between categorical data, measurement theory, and tactile discrimination. With this previous work as a foundation, we describe our research efforts with haptic and auditory maps—the Haptic Soundscapes Project. Haptic Soundscapes maps allow blind and visually-impaired individuals to feel map features through force feedback devices and hear auditory cues that add both redundant and complementary information. Recent experimental work by the authors has led to several recommended practices for cartographic data simplification, object size discrimination, shape identification, and general interface navigation. The authors also present haptic and auditory mapping examples to illustrate design ideas, algorithms, and technical requirements. Future prospects for automated haptic and auditory map creation are discussed and presented in the context of the past work in generating maps for the blind and visually impaired from cartographic data.

Phlebotomus papatasi sand flies, the vectors of Leishmania major, differ genetically in their susceptibility to the pathogens. The costs of infection appear to be so great that selection against Leishmania-susceptible flies could presumably occur, unless susceptibility is compensated for by some advantage. Foci of P. papatasi-transmitted L. major are mainly found in arid habitats where seasonal stress of dehydration and heat reduces the quantity of sugar in plant leaves. The sand flies feed on these leaves and with the lack of essential sugar only a few survive long enough to deposit eggs and transmit Leishmania. This association suggested that susceptibility to L. major infection may be linked with advantageous tolerance of sugar deprivation. Here we show that desert sand flies, provided with excess sugar, became progressively resistant to infection. Selection for survival under sugar-poor conditions increased the susceptibility of parent and first-generation offspring by more than 2-fold. The leaves of plants, on which flies naturally feed, contain more sugar in irrigated than in arid habitats. About 85% of first-generation flies colonized from a desert habitat retain experimental Leishmania infection compared to 25% of offspring of flies from irrigated sites.

Thirty-eight people with visual impairments learned a 483-meter novel route through a university campus in four groups: verbalization, modeling, pointing, and control. The performance of all four groups improved with greater experience of the route, but the modeling group improved more than did the control group.

This is a summary of the recent work on some glycosidases of sand flies and theirLeishmaniaparasites. Glycosidases catalyze the hydrolysis of complex sugar subunits of polysaccharides into simple sugars.Leishmania majorparasites secrete chitinase andN-acetylglucosaminase, which enables them to survive in the gut of the sand fly and are important in facilitating their transmission by the phlebotomine sand flyPhlebotomus papatasi. These enzymes are found in a wide range of trypanosomatids and the gene locus is highly conserved. The sand flies feed on plants and the ingested tissues may contain cellulose particles that the sand flies are unable to digest. Cellulolytic enzymes are secreted byL. majorpromastigotes and this may help to break down cellulose in infected flies and sustain their growth. Starch is a main photosynthesis product that is stored in leaves. Starch grains have been found in the midguts of field caught sand flies and α-amylase, the specific enzyme for starch, has been found in the salivary glands and other organs ofLutzomyia longipalpisandP. papatasi. α-Amylase and α-glucosidase are expressed byL. majorpromastigotes and α-glucosidase is secreted by several trypanosomatid genera, but not by all those examined. Primers originally designed to amplifyP. papatasiamylase DNA sequences, by polymerase chain reaction (PCR), also amplified DNA from all Old WorldLeishmaniaspecies, indicating that the gene is highly conserved between sand flies and these parasites.

Radio Doppler data generated by the Deep Space Network (DSN) from five encounters of the Galileo spacecraft with Callisto, Jupiter's outermost Galilean satellite, have been used to determine the mass (GM) and unnormalized quadrupole gravity coefficients in Callisto's external gravitational field. The results are GM=(7179.292±0.009) km3 s−2, J2=(32.7±0.8)×10−6, C22=(10.2±0.3)×10−6, S22=(−1.1±0.3)×10−6, C21=(0.0±0.3)×10−6, and S21=(0.0±1.6)×10−6. Also, four spacecraft images of Callisto have been used to determine its mean radius. The result is R=(2410.3±1.5) km, with no detectable deviation from sphericity. Derived parameters are Callisto's mean density of (1834.4±3.4) kg m−3 and axial moment of inertia C/MR2=0.3549±0.0042. While the mean density indicates that Callisto is a mixture of rock and ice, the moment of inertia is too small for a homogeneous mixture. Accordingly, we present a suite of possible two- and three-layer interior models that satisfy the given constraints for radius, density, and moment of inertia. While not unique, these models show that Callisto cannot be entirely differentiated, and that there must exist a region of mixed ice and rock–metal, possibly extending to the center of the satellite.

The Galileo spacecraft began its orbital tour of the Jovian system in December of 1995 and completed its eleven orbit prime mission in November of 1997 having had seventeen close encounters with the Galilean satellites. Earlier papers discussed the determination of the spacecraft orbit in support of mission operations from arrival at Jupiter through the first twelve orbits. In this paper we report on the reconstruction of the spacecraft trajectory for the entire prime mission, the development of a consistent set of ephemerides for the Galilean satellites, the improvement of the ephemeris of Jupiter, the determination of the gravity field of the Jovian system, and the determination of the orientation of the pole of Jupiter.

Seven specific-pathogen-free (SPF) ponies, 1–5 years old, were exposed to Borrelia burgdorferi–infected adult ticks while being treated with dexamethasone over 5 consecutive days. One SPF pony (pony No. 178) was first exposed to laboratory-reared nymphs without B. burgdorferi infection and 3 weeks later was exposed to B. burgdorferi–infected adult ticks with concurrent dexamethasone treatment for 5 consecutive days. Four uninfected ponies treated with dexamethasone, exposed to laboratory-reared ticks without B. burgdorferi infection served as uninfected controls. Clinical signs, bacteriologic culture, polymerase chain reaction (PCR) for bacterial DNA, immunologic responses, and gross lesions and histopathologic changes were investigated during the experiment or at necropsy 9 months after tick exposure. In all of the seven challenged ponies, infection with B. burgdorferi was detected from monthly skin biopsies and various tissues at postmortem examination by culture and by PCR. However, pony No. 178 exposed to laboratory-reared nymphs (without B. burgdorferi infection) and challenged with B. burgdorferi–infected adult ticks 2 months later did not develop a B. burgdorferi infection. All of the infected ponies seroconverted. Control ponies and pony No. 178 were negative by culture, PCR, and serology. Except for skin lesions, we failed to induce any significant histopathologic changes in this study. This is the first report of successful tick-induced experimental infection in ponies by exposure to B. burgdorferi–infected ticks. This Lyme disease model will be very useful to evaluate efficacy of vaccines against the Lyme agent and the effect of antibiotic therapy on horses infected with B. burgdorferi.

Ultraviolet photolysis of hexanes solutions containing the complexes M(CO)6 (M = Cr, Mo, W) or CpMn(CO)3 (Cp = η⁵-C5H5) and excess thiophene (T*) (T* = 2,5-dimethylthiophene (2,5-Me2T), benzothiophene (BT), or dibenzothiophene (DBT)) produces the η¹(S)-T* complexes (CO)5M(η¹(S)-T*) 1−8 or Cp(CO)2Mn(η¹(S)-T*) 9−11, respectively. However, when T* = DBT and M = Mo, a mixture of two products results, which includes (CO)5Mo(η¹(S)-DBT), 4a, and the π-complex (CO)3Mo(η⁶-DBT), 4b, as detected by ¹H NMR spectroscopy. Only the complexes (CO)5W(η¹(S)-DBT) (1), (CO)5Cr(η¹(S)-DBT) (5), and Cp(CO)2Mn(η¹(S)-DBT) (9) were sufficiently stable (several days) to be isolated and characterized by elemental analyses. Rates of DBT ligand displacement by CO (1 atm) at room temperature decreased in the order 5 > 1 > 9. Single-crystal, X-ray structural determinations are reported for 1, 5, and 9. The tilt angle (θ) of the DBT ligand in these and related complexes is discussed in terms of π-back-bonding to the DBT ligand.

We have identified two metabolites of clofazimine (B663; Lamprene; 3-(p-chloroanilino)-10-(p-chlorophenyl)-2,10-dihydro-2-isopropyliminophenazine) in our initial investigation of its metabolism in leprosy patients. Based on mass, ultraviolet, and visible spectrometry, we characterized an unconjugated (metabolite I, 3-(p-hydroxyanilino)-10-(p-chlorophenyl)-2,10-dihydro-2-isopropyliminophenazine ) and a conjugated (metabolite II, 3-(beta-D-glucopyranosiduronic acid)-10-(p-chlorophenyl)-2,10-dihydro-2-isopropyliminophenazine) metabolite from the urine of patients. Both metabolites were red in color, similar to clofazimine; however, both were considerably more polar than the parent drug. We suggest that metabolite I was formed by a hydrolytic dehalogenation reaction, and metabolite II by hydrolytic deamination followed by glucuronidation.

Marrow transplantation is a potentially curative treatment for patients with lymphohematopoietic malignancies. We report here a case of syngeneic transplantation in a 39‐year‐old male with chemotherapy‐resistant progressive chronic lymphocytic leukemia. Following conditioning therapy with fractionated total body irradiation, etoposide and cyclophosphamide and transplantation from a monozygotic twin brother, the patient achieved a complete remission and remains disease‐free 15 months after transplant. This observation indicates that, in principle, chronic lymphocytic leukemia is a disease curable by marrow transplantation.

Somatic cell genetic approaches utilizing the cellular mosaicism present in women heterozygous for glucose-6-phosphate dehydrogenase (G6PD) have provided information relevant to the pathogenesis of some neoplastic disorders. With these techniques, we studied a 61-year-old woman with a myelodysplastic syndrome. GdB/GdA heterozygosity was demonstrated in skin and cultured T lymphocytes, which exhibited both A and B type G6PD. In contrast, erythrocytes, platelets, granulocytes, and marrow nucleated cells displayed almost exclusively G6PD type B. In addition, 21 of 24 Epstein-Barr virus-transformed B lymphoblastoid lines that expressed a single immunoglobulin light chain showed only type B G6PD, suggesting that the stem cells involved by this disease were clonal and could differentiate to B lymphocytes as well as to mature granulocytes, erythrocytes , and platelets. Cultured skin fibroblasts and phytohemagglutinin-stimulated lymphocytes were karyotypically normal, but two independent abnormalities were found in marrow--47,XX, +8 and 46,XX,del(11)(q23). None of 14 type B G6PD lymphoblastoid lines analyzed in detail contained these karyotypic abnormalities, which strongly suggests that a visible chromosomal alteration is not the sole step in the development of this disease. We hypothesize that at least two events are involved in the pathogenesis of this patient's myelodysplasia: one causing proliferation of a clone of genetically unstable pluripotent stem cells and another inducing chromosomal abnormalities in its descendants.

The in vitro phagocytosis of bothBabesia bovis-infected red cells and of parasites exposed by lysis of infected red blood cells is demonstrated in a phagocytic mouse model. Twenty-fourB. bovis immune sera were tested alone or as a pool as were antibodies (DS antibodies) raised against aB. bovis protective fraction, prepared by dextran sulfate precipitation. All the immune sera failed to promote significant levels of phagocytosis, whereas the other antibodies (DS antibodies) consistently induced phagocytosis of infected cells in all the experiments carried out. This study shows that antibody specificity is critical to the opsonization of infected red cells and parasites during in vitro phagocytosis and suggests that phagocytosis is one of the mechanisms in the in vivo immune response againstBabesia species.

Two new enzyme-linked immunosorbent assayes (ELISA) for the diagnosis ofBabesia bovisin cattle are described. The ELISA using a native antigen is more sensitive and less laborious than the assays described previously, because it does not require adsorption of sera with bovine erythrocytes. The second ELISA, using a recombinantB. bovisantigen expressed inEscherichia coli, was both sensitive and specific. It is suitable to replace the native antigen, thus avoiding large batch-to-batch variations in antigen preparations and the need to sacrifice experimental cattle.

Abstract: The partitioning of Sr between calcite, dolomite and liquids is essentially independent of temperature between 150 and 350 C. The partition coefficients corrected for number of cation sites are b calc=0.096 and b dol= 0.048 for 1 mol cations/6 mol H2O liquid. Upon dilution the partition coefficients increase, but their ratio stays constant at about 2∶1. This ratio is due to the fact that calcite has twice as many Ca-sites for Sr-substitution as dolomite. The 2∶1 relationship is also observed in natural calcite and dolomite which have undergone diagenesis. The temperature independence of partitioning is caused by the relatively small thermal expansion of calcite and dolomite. Thermal expansion between 25 and 400 C was found to follow the equations V calc=7.010−4 T(C)+36.95 and V dol=6.910−4 T(C)+32.24, V: cm3/mol. Therefore calcite and dolomite cannot serve as a temperature indicator. To have an ideal geothermometer a mineral pair with high and low thermal expansion is required. Literature date demonstrate that wurtzite, sphalerite, and galena are such minerals.

Abstract: During the recent 1983 eruption of Kilauea Volcano in Hawaii, a field measurement of electrical resistivity was made in an 1118C molten lava flow. A probe containing a four electrode. Wenner aray was inserted into the molten basaltic lava flow at a point about 100 m from the erupting vent. The probe indicated an electrical resistivity of approximately 40 ohm-m for the freshly-erupted molten lava. This value is consistent with existing, but sparce, laboratory data for molten rock in this temperature range.

Evaluation of the use of food-dye marking method for the study of sandfly behaviour was carried out in Baringo district, Kenya. A solution of sucrose and food dye was sprayed as bait on the vegetation around a selected source of flies in an animal burrow. The extent of marking and distribution of coloured flies within a radius of 200 m was monitored for four nights. The species caught were Sergentomyia clydei, S. schwetzi, S. antennatus, S. squamipleuris, S. bedfordi, S. africanus S. ingramiand S. affinisand the number of coloured flies was 1017. Feeding on the dyed solution labelled 68.9% of the exiting flies near the burrow and 49.2% of the flies caught at the burrow’s entrance. The total number of coloured flies caught at a distance of 50, 100, 150 and 200 m was similar toa linear distribution. The greater numbers of S. clydeicaught at 200 m and the smaller numbers of S. squamipleurisand S. ingramitrapped between 50 and 200 m deviated from this pattern. These results are discussed as well as the possible application of the method. L’evaluation de la methode de marquage par coloration alimentaire a ete faite dans la region de Baringo, au Kenya. Comme nourriture des phlebotomes, une solution de sucrose contenant un colorant alimentaire a ete vaporisee sur la vegetation autour d’un terrier, ce terrier etant source de mouches. La repartition des mouches colorees a ete controlee pendant 4 nuits, dans un rayon de 200 m. Les especes capturees ont ete Sergentomyia clydei, S. schwetzi, S. antennatus, S. squamipleuris, S. bedfordi, S. africanus, S. ingramiet S. affinis. Le nombre total de mouches colorees a ete de 1017. L’alimentation coloree ingeree a marque 68.9% des mouches capturees aux alentours du terrier et 49.2% des celles capturees a son entree. Le nombre total de mouches colorees, capturees dans un rayon de 50, 100, 150 et 200 m. A ete semblable a la distribution linearle calculee, bien qu’il y ait eu quelques variations. Les plus grandes d’entre elles ont ete pour S. clydeicapturees a 200 m. et les plus petites pour S. squamipleuriset S. ingramicapturees entre 50 et 200 m. Ces resultats ont ete discutes ainsi que les possibilites d’application de cette methode.

GIS, with their predominantly visual communication of spatial information, may appear to have little to offer people with visual impairments or blindness. However, because GIS store and manage the spatial relations between objects, alternative, non‐visual ways to communicate this information can be utilized. As such, modified GIS could provide people with visual impairments access to detailed spatial information that would aid spatial learning, orientation, and spatial choice and decision making. In this paper, we explore the ways that GIS have been, and might be, adapted for use by people with visual impairments or blindness. We review current developments, report upon a small experimental study that compares the ability of GIS‐based and various adaptive technologies to communicate spatial information using non‐visual media, and provide an agenda for future research. We argue that adapted GIS hold much promise for implicitly improving the quality of life for visually impaired people by increasing mobility and independence.

See related editorial, ''CPR and Ventricular Fibrillation: Lasts Longer, Ends Better.'' Study objective: To assess whether bystander CPR (BCPR) on collapse affects initial rhythm and outcome in patients with witnessed, unmonitored out-of-hospital cardiac arrest (OHCA). Design: Prospective cohort study. Student's t test, the @g^2 test, and logistic regression were used for analysis. Setting: Suburban emergency medical service (EMS) system. Participants: Patients 19 years or older with witnessed OHCA of presumed cardiac origin who experienced cardiac arrest before EMS arrival between July 1989 and July 1993. Results: Of 722 patients who met the entry criteria, 153 received BCPR. Patients who received BCPR were younger than those who did not: 62.5+/-15.4 years versus 66.8+/-15.1 years (P<.01). We found no differences in basic or advanced life support response intervals or in frequency of AED use. More patients initially had ventricular fibrillation (VF) in the BCPR group: 80.9% versus 61.4% (P<.01). The interval to definitive care for ventricular tachycardia (VT)/VF was longer for the BCPR group (8.59+/-5.3 versus 7.45+/-4.7 minutes; P<.05). The percentage of patients discharged alive who were initially in VT/VF was higher in the BCPR group: 18.3% versus 8.4% (P<.001). In a multivariate model, BCPR is a significant predictor for VT/VF and live discharge with adjusted ORs of 2.7 (95% CI, 1.7 to 4.4) and 2.4 (95% CI, 1.5 to 4.0), respectively. For those patients in VT/VF, BCPR predicted live discharge from hospital with an adjusted OR of 2.1 (95% CI, 1.2 to 3.6). Conclusion: Patients who receive BCPR are more often found in VT/VF and have an increased rate of live discharge, with controls for age and response and definitive care intervals. For VT/VF patients, BCPR is associated with an increased rate of live discharge. [Swor RA, Jackson RE, Cynar M, Sadler E, Basse E, Boji B, Rivera-Rivera EJ, Maher A, Grubb W, Jacobson R, Dalbec DL: Bystander CPR, ventricular fibrillation, and survival in witnessed, unmonitored out-of-hospital cardiac arrest. Ann Emerg Med June 1995;25:780-784.]

A number of star-like images have been found on archival photographic plates, however there is debate as to whether these are optical emissions relating to Gamma-Ray bursts, or simply plate defects. Results from photographic science are summarized so that the characteristic shape of different types of images on photographic plates can be theoretically predicted. Explanation for the formation of the relief image and reasons for its continued study are described. New methods in the use of laser scanning confocal microscopy are presented to study the relief image and the depthwise disposition of silver so that a test procedure can be established to end the speculation surrounding the astrophysical truth of stellar-like images on photographic plates.

The principal components transform is a standard lechnique for the enhancemenl of contrast in multi-spectral images. The contrast that is recorded in the image, as between-band variances, can by means of a linear transformation of the multidimensional image space, be concentrated in the primary band of the transformed image. This is quite effective where the recorded values are well separated in image space. However, where the separation is small, for example, where similar coloured targets are recorded with visible spectral bands, the method is more likely to reduce the signal-to-noise ratio of the targets because, although the contrast is increased, the noise is increased by a greater amount. For such targets a simple averaging of the images may be more effective in increasing target discrimination by reducing the noise level. If the spectral reflectances of the targets are known, or can be estimated a priori, then greatly enhanced discrimination can be achieved by altering the system exposure response (SER).

Blood from a woman with unexplained erythrocytosis had increased oxygen affinity, but no abnormality could be detected by electrophoresis or chromatography of her hemolysate. Separation of the tryptic peptides of her beta chains disclosed two half-sized peaks in the regions of beta T- 11. The faster of these was abnormal, with the structure beta 101 Glu replaced by Asp. The new hemoglobin was called “Potomac.” Three of the proband's four surviving siblings and both of her children were carriers. Differences in the ratio of carrier: normal children born to male of female carriers of 23 other high-affinity hemoglobins were not significant. The high proportion of carriers in this kindred was probably due to chance alone, and not because high maternal oxygen affinity interfered with oxygen transport to fetuses with normal hemoglobin.

Article abstract—We applied functional magnetic resonance imaging (FMRI) to map the somatotopic organization of the primary motor cortex using voluntary movements of the hand, arm, and foot. Eight right-handed healthy subjects performed self-paced, repetitive, flexiodextension movements of the limbs while undergoing echo-planar imaging. Four subjects performed movements of the right fingers and toes, while the remaining subjects performed movements of the right fingers and elbow joint. There was statistically significant functional activity in the left primary motor cortex in all subjects. The pattern of functional activity followed a topographic representation: finger movements resulted in signal intensity changes over the convexity of the left motor cortex, whereas toe movements produced changes either at the interhemispheric fissure or on the dorsolateral surface adjacent to the interhemispheric fissure. Elbow movements overlapped the more medial signal intensity changes observed with finger movements. Functionally active regions were confined to the cortical ribbon and followed the gyral anatomy closely. These findings indicate that FMRI is capable of generating somatotopic maps of the primary motor cortex in individual subjects.

Abstract: The development of tension and shortening in cardiac and skeletal muscle exhibits phenomena suggestive of control by feedback mechanisms at the molecular level. Two of these, presented here, may have surprising implications for the cross-bridge theory of muscular contraction. It can be argued, from the basis of the cross-bridge theory, that the extended muscle is unstable against further imposed stretch by reason of a corresponding decrease of generated tension. Certain measurements of static tension versus muscle length appear to corroborate this conclusion. On the other hand, there is direct evidence for the dynamic stability of muscle at longer lengths. The cross-bridge theory may be incorrect in this regard, and cross-bridges may contain a negative feedback mechanism; but it may be the case that the contradiction arises out of inappropriately extrapolating the static length-tension data to a dynamic situation. By monitoring the sarcomere length of a contracting muscle, it can be seen that shortening does not proceed smoothly, but in more or less discontinuous jumps. This “stepwise” shortening shows evidence of synchronization across a region of a muscle, and suggests some positive feedback process at work. Some speculations are offered as to possible mechanisms, including load-dependent signalling, diffusion, cooperative effects, and repeated cycles of substrate consumption, concomitant with shortening, alternating with a “catch-up” period of substrate production.

The circumstances which permit the establishment of Leishmania infections in sandflies were investigated by altering the growth conditions for L. donovani parasites in the unsuitable vector Phlebotomus papatasi. Only 5·0% of the sandflies harboured a few parasites 3 days after feeding on promastigotes in defibrinated blood. Heparinized blood or the addition of trypsin inhibitor to the meals allowed persistence of infections (day 6) in 9·9% and 25·8% of the flies respectively. Meals of erythrocytes, saline and amastigotes produced 44·4% fly infection on day 6, while similar promastigote-initiated infections remained in 70·3% of the flies. Proteolytic activities in the guts of sandflies fed on the above meals without parasites, were the highest after defibrinated bloodmeals. Erythrocytes with saline decreased the maximal alkaline protease level from 20·8 U to 13·5 U/fly; that of trypsin from 3·9 U to 1·8 U/fly and that of the aminopeptidase from 5·5 U to 3·9 U/fly. After meals of heparinized blood, the maximal alkaline protease activity (12·0 U/fly) was also much lower than after defibrinated blood-feeding. The different diets which resulted in comparatively low enzymatic activities, including blood with trypsin inhibitor, also promoted the survival of infections. This implies that the proteolytic activity in the sandfly gut modulates the vector susceptibility.

This article is so apposite to our continuing series on aspects of image permanence and conservation in all its forms, that we have sought permission to reprint it in its entirety from The Journal of Photographic Science (1985) 33, 177-181, in which it first appeared. It presents a review of the evidence available concerning the permanence of high-resolution images and holograms recorded on silver halide emulsions. Preliminary recommendations are included for the storage and display of holograms to avoid possible problems of image deterioration

The production and storage of explosives has resulted in the environmental accumulation of the mutagen 2,4,6‐trinitrotoluene (TNT). In order to characterize the production of mutagenic urinary metabolites, 6‐week old male Fischer 344 rats were administered 75 mg of TNT/kg or DMSO vehicle by gavage. The animals were placed into metabolism cages, and urine was collected for 24 hr. Following filtration, metabolites in the urine were deconjugated with sulfatase and β‐glucuronidase and concentrated by solid phase extraction. The eluate was fractionated by reverse‐phase high‐performance liquid chromatography (HPLC) using acetonitrile/water, and the fractions were solvent exchanged in DMSO by nitrogen evaporation. Each HPLC fraction was bioassayed in strains TA98, TA98NR, TA100, and TA100NR without metabolic activation using a microsuspension modification of the Salmonella histidine reversion assay. Fractions 3, 5–18, 21, 22, and 24–26 contained mutagens detected by strain TA98. In the nitroreductase‐deficient strain TA98NR, some mutagenic activity was lost; however, fractions 3, 6, 9–11, 15, and 25 clearly contained direct‐acting mutagens. Fewer fractions were positive in strain TA100 (9–16, 19, 20, and 25) with less activity observed in the nitroreductase deficient strain TA100NR (fractions 3, 12, 14, 15, and 25). Although some mutagenic activity coeluted with known TNT metabolite standards, there were still many unidentified mutagenic peaks. Environ. Mol. Mutagen. 30:298–302, 1997. © 1997 Wiley‐Liss, Inc.

Four pups in a litter of eight Labrador Retrievers suddenly developed hind limb weakness. In three, paralysis ascended rapidly resulting in quadriplegia, cervical weakness, dysphagia and death. Postmortem examination revealed a severe polyradiculoneuritis in which roots, ganglia, and spinal and cranial nerves were heavily infiltrated by lymphocytes, plasma cells and macrophages and contained abundant protozoan pseudocysts. On sections of the brain and spinal cord protozoa were less frequent and appeared independent of the glial nodules which marked focal areas of necrosis. The organisms innitially were thought to beToxoplasma gondii, but this supposition was not supported by serological, immunocytochemical, or electron microscopic findings. Ultrastructurally the organisms resembled an unidentified sporozoan parasite, which has been reported in the CNS of dogs in Scandinavia. The inflamed spinal roots contained many degenerated and demyelinated axons. Electron microscopic studies indicated that the tachyzoite-like organisms, through their invasive and proliferative activities, brough about many of the degenerative changes in the Schwann cells and axons of the spinal roots and nerves.

An array consisting of ocean bottom seismometer and on-bottom hydrophones, was used to conduct a seismic experiment on 0.4 Ma crust east of the Juan de Fuca Ridge. Seismic sources were large (>50 kg) explosive charges detonated by SUS devices set to explode at 1829 or 2438 m nominal depth. The objectives of the experiment were to determine the compressional wave velocity and attenuation structures of the uppermost 500 m depth. The relative positions of shots and receivers were originally determined by treating each shot-receiver pair independently, via raytracing of various water waves. Due to the reflection of some of these water waves by the rough bottom, significant scatter resulted, preventing a determination of a physically realizable velocity-depth function. A new method is described that co-locates shot and receiver positions, including receiver depths consistent withseabeam bathymetry, using only the water waves that do not interact with the bottom. Several potential pitfalls are outlined using this method. A stable solution could only be achieved by discarding shots located well outside the array. The water path corrections were applied to the refracted arrivals, again using theseabeam bathymetry. The joint inversion location procedure, along with the use of precise gridded bathymetry, reduced the travel time scatter to a level whereby a velocity-depth function could be determined. The results, using only the hydrophone data, indicate an initial velocity at the seafloor of 2.7 km s-1 with gradients from 4.6 s-1 slowly decreasing to 4.1 s-1 at 679 m depth. This velocity is similar to others conducted over very young oceanic crust, and can be interpreted as being due to a high porosity at the surface, due to cracks, fissures, and open pores, which rapidly diminish with depth.

The crystal and molecular structure of the title complex determined by x-ray diffraction techniques demonstrates that the thermodynamically unstable form of the phosphorinane ligand (i.e., phosphorus lone pair axial) coordinates to the metal with retention of configuration at phosphorus. It is noted that the CH3O group of both ligands adopts a conformation such that the P(OC)3 moiety in each ligand possesses a spatial arrangement similar to that of the P(OCH3)3 ligand in complexes whose structures have been determined (Ref. 16).