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Evolutionary radiations have been well documented in plants and insects, and natural selection may often underly these radiations. If radiations are adaptive, the diversity of species could be due to ecological speciation in these lineages. Agromyzid flies exhibit patterns of repeated host-associated radiations. We investigated whether host-associated population divergence and evidence of divergent selection exist in the leaf miner Phytomyza glabricola on its sympatric host plants, the holly species, Ilex coriacea and I. glabra. Using AFLPs and nuclear sequence data, we found substantial genetic divergence between host-associated populations of these flies throughout their geographic range. Genome scans using the AFLP data identified 13 loci under divergent selection, consistent with processes of ecological speciation. EF-1α data suggest that I. glabra is the original host of P. glabricola and that I. coriacea is the novel host, but the AFLP data are ambiguous with regard to directionality of the host shift.

Boxwood (Buxus spp.) are commercially important evergreen ornamental plants with an annual market value of over $103 million in the United States. The recent U.S. incursion of boxwood blight disease caused by the fungus Calonectria pseudonaviculata (syn. Cylindrocladium pseudonaviculatum, Cy. buxicola) threatens the health and productivity of boxwood in both landscape plantings and nurseries. The first confirmed U.S. reports of the disease were made from Connecticut and North Carolina in November 2011 (2,4), followed by diagnoses in 10 additional states during 2012 and 2013. By August 2013, symptoms consistent with boxwood blight had been observed from B. sempervirens in Delaware, Maryland, New Jersey, and southeastern New York. Affected plants showed rapid onset of disease symptoms: dark brown to black spots or diffuse dark areas on leaves, followed by defoliation. Narrow, elongate black cankers also formed on current season shoots. Symptomatic stems and leaves were placed in petri dishes with moistened filter paper at 22°C for 3 days under continuous light. Conidiophores were excised, then placed on potato dextrose agar amended with streptomycin and neomycin (0.3 g/l). Resultant colonies showed dark brown pigmentation at the colony center surrounded by tan to reddish brown rings with white mycelia at the advancing edge. Conidia (n = 30 per isolate) were hyaline, cylindrical, rounded at both ends, with a single septum (45 to 76 × 4 to 6 μm; avg. 63 × 5 μm). Conidiophores (n = 20 per isolate) comprised a stipe, a hyaline septate stipe extension (length 119 to 192 μm; avg. 150 μm) and a terminal ellipsoidal vesicle (diameter 4 to 10 μm; avg. 7 μm). Based on morphological characteristics, the causal agent was identified as C. pseudonaviculata (1,4). Voucher specimens were deposited in the U.S. National Fungus Collections (BPI 892698 to 701). To verify morphological diagnosis, genomic DNA was extracted from fungal biomass grown in liquid cultures of yeast extract peptone dextrose media. A portion of the β-tubulin gene (TUB2) was PCR amplified and sequenced bi-directionally using primers Bta/Bt2b (3). BLASTn searches of NCBI GenBank databases using the TUB2 sequences (Accession Nos. KF785808 to 11) demonstrated 96 to 100% sequence identity with other C. pseudonaviculata isolates. To confirm pathogenicity, 5-month-old B. sempervirens and B. microphylla seedlings were spray-inoculated with a spore suspension of 1 × 104 conidia/ml. One isolate from each state was independently tested with four replicates each. Non-inoculated water-sprayed plants served as negative controls. Plants were maintained in growth chambers at 22°C under constant light. Blight symptoms developed 4 to 5 days post inoculation. C. pseudonaviculata was re-isolated from inoculated plants; no symptoms or signs were observed from control plants. To our knowledge, this is the first report of C. pseudonaviculata in the states of Delaware, Maryland, New Jersey, and New York. This report demonstrates that C. pseudonaviculata is now widespread across the United States eastern seaboard, and represents a substantial threat to boxwood plants in North American landscapes and nurseries. References: (1) P. Crous et al. Sydowia 54:23, 2002. (2) D. F. Farr and A. Y. Rossman. Fungal Databases, USDA-ARS. Retrieved from http://nt.ars-grin.gov/fungaldatabases , 30 August 2013. (3) N. L. Glass and G. C. Donaldson. Appl. Environ. Microbiol. 61:1323, 1995. (4) K. L. Ivors et al. Plant Dis. 96:1070, 2012.

Subduction-related transport of water into the mantle has significant dynamical and geochemical implications. Dehydration of hydrous phases within the slab can introduce water into the transition zone and lower mantle, potentially hydrating nominally anhydrous minerals (NAM) and impacting the viscosity and density structure of the mantle over a wide area. We present models of fluid transport and mantle hydration in the vicinity of a deeply subducting slab, focusing on the fate of water released by deep dehydration reaction in the subducted serpentinized mantle. A sharp decrease in water storage capacity across the lower boundary of the transition zone may produce “secondary dehydration” of hydrated NAM, leading to precipitation of a hydrous fluid and heterogeneous hydration of the transition zone. Rapid fluid migration relative to the solid flow field can lead to a broad region of diffuse hydration within the upper mantle wedge and the potential for localized melt regions at the top of the transition zone coincident with fluid pathways. Slower fluid migration instead implies that the fluid phase can be transported deep into the lower mantle. Water stabilized in NAM and as a free fluid can initiate upwelling within and above the transition zone. A less abrupt change in water storage capacity across the base of the transition zone leads to high NAM water contents in a channel adjacent to the slab where viscosity is reduced. However, seismic and electromagnetic observations of hydration in the transition zone are most compatible with a sudden drop of water storage capacity.

This paper describes a two-limb single-pass modeling approach constrained by vent temperature, heat flow, vent geochemistry, active-source seismology, and seismically inferred circulation geometry to provide first-order constraints on crustal permeability, conductive boundary layer thickness, fluid residence times, and magma replenishment rates for the magma-hydrothermal system at the East Pacific Rise (EPR) near 9°50'N. Geochemical data from black smokers and nearby diffuse-flow patches, as well as an estimate of heat flow partitioning, suggest that nearly 90% of the heat output stems from heat supplied by the subaxial magma chamber, even though almost 90% of that output appears as diffuse flow at the seafloor. Estimates of magma replenishment rates are consistent with the evolution of lava chemistry over the eruption cycle between 1991–1992 and 2005–2006. If the recharge surface area is 105 m2, a one-dimensional model of hydrothermal recharge using EPR 9°50'N parameters gives rise to rapid sealing as a result of anhydrite precipitation; however, if the area of recharge widens at depth to ~ 106 m2, sealing by anhydrite precipitation may not significantly affect hydrothermal circulation.

Special Issue on Coastal Ocean Processes, Observing Technologies and Models, Oceanography, Volume 21, No. 4. December 2008.

Expanded marine Holocene archives are relatively scarce in the Mediterranean Sea because most of the sediments were trapped in catchment areas during this period. Mud belts are most suitable targets to access expanded Holocene records. These sedimentary bodies represent excellent archives for the study of sea-land interactions and notably the impact of the hydrological activity on sediment accumulation. We retrieved a 7.2 m-long sediment core from the Rhone mud belt in the Gulf of Lions in an area where the average accumulation rate is of ca. 0.70 m/1000 years. This core thus provides a continuous and high-resolution record of the last 10 ka cal BP. A multi-proxy dataset (XRF-core scan, 14C dates, grain size and organic matter analysis) combined with seismic stratigraphic analysis was used to document decadal to centennial changes of the Rhone hydrological activity. Our results show that 1) the Early Holocene was characterized by high sediment delivery likely indicative of local intense (but short duration) rainfall events , 2) important sediment delivery around 7 ka cal BP roughly presumably related to increased river flux, 3) a progressive increase of continental/marine input during the Mid-Holocene despite increased distance from river outlets due to sea-level rise possibly related to higher atmospheric humidity caused by the southward migration of the storm tracks in the North Atlantic, 4) multi-decadal to centennial humid events in the Late Holocene. Some of these events correspond to the cold periods identified in the North Atlantic (Little Ice Age, LIA; Dark Age) and also coincide with time intervals of major floods a in the Northern Alps. Other humid events are also observed during relatively warm periods (Roman Humid Period and Medieval Climate Anomaly).

Recently diverged taxa often show discordance in genetic divergence among genomic loci, where some loci show strong divergence and others show none at all. Genetic studies alone cannot distinguish among the possible mechanisms but experimental studies on other aspects of divergence may provide guidance in the inference of causes of observed discordances. In this study, we used no-choice mating trials to test for the presence of reproductive isolation between host races of the leaf-mining fly, Phytomyza glabricola on its two holly host species, Ilex coriacea and I. glabra. These trials inform our effort to determine the cause of significant differences in the degree of divergence of nuclear and mitochondrial loci of flies collected from the two host plants. We present evidence of reproductive isolation between host races in a controlled greenhouse setting: significantly more mate pairs consisting of flies from the same host plant species produced offspring than inter-host mate pairs, which produced no offspring. We also tested whether the presence of the natal or non-natal host plant affects reproductive success. Flies collected from I. coriacea were more likely to produce offspring when in the presence of the natal host, whereas the presence or absence of either the natal or non-natal host had no effect on flies collected from I. glabra. The results indicate discordant patterns of nuclear and mitochondrial divergence among host races of P. glabricola are likely due to incomplete lineage sorting, and the host races may be well on their way to becoming biological species.

[1] Crustal thickness variations at the ultraslow spreading 10–16°E region of the Southwest Indian Ridge are used to constrain melt migration processes. In the study area, ridge morphology correlates with the obliquity of the ridge axis with respect to the spreading direction. A long oblique “supersegment”, nearly devoid of magmatism, is flanked at either end by robust magmatic centers (Joseph Mayes Seamount and Narrowgate segment) of much lesser obliquity. Plate-driven mantle flow and temperature structure are calculated in 3-D based on the observed ridge segmentation. Melt extraction is assumed to occur in three steps: (1) vertical migration out of the melting region, (2) focusing along an inclined permeability barrier, and (3) extraction when the melt enters a region shallower than ∼35 km within 5 km of the ridge axis. No crust is predicted in our model along the oblique supersegment. The formation of Joseph Mayes Seamount is consistent with an on-axis melt anomaly induced by the local orthogonal spreading. The crustal thickness anomaly at Narrowgate results from melt extracted at a tectonic damage zone as it travels along the axis toward regions of lesser obliquity. Orthogonal spreading enhances the Narrowgate crustal thickness anomaly but is not necessary for it. The lack of a residual mantle Bouguer gravity high along the oblique supersegment can be explained by deep serpentization of the upper mantle permissible by the thermal structure of this ridge segment. Buoyancy-driven upwelling and/or mantle heterogeneities are not required to explain the extreme focusing of melt in the study area.

[1] Throughout the global mid-ocean ridge system, transform faults offset spreading centers. Conductive cooling may be more efficient beneath transform faults, producing a thickened lithosphere that directs melt away from the transform. However, recent observations of thickened crust along transform faults at fast ridges suggest melt redistribution toward transforms, intra-crustal melt production, or efficient extraction of melt. We apply a 3-D model of melt migration and extraction along an oceanic transform domain bounded by ridge segments. Melt is assumed to travel vertically before collecting and migrating beneath a low-permeability boundary inclined towards the ridge axis. A melt extraction zone, which may be geologically interpreted as the presence of faults and/or dikes leading to rapid lateral and vertical melt migration toward plate boundaries, affects the pattern of crustal accretion at segmented ridges. First, we examine a generic ridge-transform-ridge geometry and then a model that represents the Siqueiros transform on the East Pacific Rise. On the basis of crustal thickness variations within the intra-transform spreading centers along the fast-slipping Siqueiros fault, we constrain the presence of a melt extraction zone within 10 km of the transform zone.

Melt focusing at mid-ocean ridges is necessary to explain the narrowness of the zone of crustal accretion and the formation of large but localized on-axis seamounts at slow and ultraslow spreading centers. It has been proposed that melt focusing is facilitated by the presence of a barrier to upward melt migration at the base of the thermal boundary layer (TBL). We assess the development of a melt impermeable boundary by modeling the geochemical evolution and crystallization history of melts as they rise into the TBL of mid-ocean ridges with different spreading rates. A permeability barrier, associated with a crystallization front controlled by the conductive thermal regime, exists for melt trajectories at slow to fast spreading ridges (≥10 mm/yr half rate). The effective lateral scope of the barrier, where the slope of the barrier exceeds a critical value that allows buoyant melt transport to the axis, generally increases with spreading rate. At all distances from the axis at ultraslow ridges and off-axis at slow spreading ridges, the weak crystallization front may prohibit formation of an efficient barrier and lead to the possibility that some fraction of melt may be incorporated into the lithospheric mantle, allowing refertilization. The protracted crystallization history and potential absence of an effective permeability barrier may explain the dearth of volcanism at ultraslow ridges and calls for a revision of lateral melt focusing scenarios at ultraslow spreading rates.

A direct adaptive controller for trajectory tracking of high-speed robots such as a direct-drive SCARA robot is presented. In this robot, nonlinear effects due to centrifugal, Coriolis, and inertial forces are more important than friction and gravity forces, unlike most industrial robots. The control law of the adaptive scheme consists of a PD regulator plus feedforward compensation of full dynamics. The feedforward terms are adjusted by an adaptation law so that the steady-state position errors are zero. With this adaptive controller, the joint acceleration measurement is not required and no inversion of the estimated mass matrix is involved. The tracking performances of the controller applied to a two-degree-of-freedom SCARA is illustrated by a real-time implementation based on a single-chip digital signal processor (DSP). >

The implementation of a self-tuning regulator for the positioning of a direct-drive servomotor is described. The servo motor is a permanent magnet DC motor in which no speed reducer is used. The auto-tuning regulator consists of two major loops. The inner loop contains a feedback (PD or PID) regulator with additional feedforward terms. The parameters of the feedforward compensation are adjusted by the outer loop, which contains an online parameter estimator. The estimator is based on a recursive least-squares equation, and the estimated parameters are the load inertia and viscous friction. This self-tuning regulator has been simulated with PC.MATLAB, and the results demonstrate the high performance of the scheme. Experimental results obtained with a small DC motor (Electrocraft E-576) are presented, and these results show good agreement with the digital simulation results. There are two innovative aspects to this work. First, parameter estimation is used to adapt the feedforward compensation terms instead of the gains of the feedback controller, as usually is the case in conventional indirect self-tuning regulators. Secondly, the complete adaptive controller has been implemented using a single-chip digital signal processor (DSP), which results in the reduction of system hardware and cost. >

Lower levels of plasma total cholesterol have been observed during severe infection, but it is not known whether the minor illnesses encountered in the general population are also associated with reduced cholesterol. This paper examines the relation between minor illness and plasma lipids, using 7- and 10-year follow-up data from more than 3,000 generally healthy participants in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. At both 7 and 10 years, approximately 8.5% of participants stated they had been "ill with cold, flu, fever, or vomiting in the past 24 hours." In both cross-sectional and longitudinal analyses, the plasma total cholesterol was about 5 mg/dl lower (p0.006) and high density lipoprotein cholesterol about 1.2 mg/dl lower (p0.12) in those who reported minor illness than in those who did not. Plasma triglycerides did not vary with minor illness. The authors conclude that reductions in plasma total, low density, and high density lipoprotein cholesterol mark an acute phase response even during minor illness. These reductions may bias surveys over a limited geographic area during a short period because the proportion with minor illness may vary locally. Because this effect should be stronger with more precise illness diagnosis, clinicians should avoid making measurements for cholesterol management when illness may alter plasma lipid levels and the resulting decisions.

Technetium-99m-teboroxime (CardioTec) is a promising new myocardial perfusion imaging agent. The purposes of this study were to define teboroxime clearance kinetics in normal and flow-restricted myocardium over a 1-hr period and to determine whether teboroxime kinetics are useful in detecting myocardial hyperperfusion. Accordingly, the circumflex arteries of 23 dogs were stenosed. By using miniature cadmium-telluride radiation detectors, myocardial teboroxime activities were continuously monitored in both the control and the stenosed zones. Myocardial clearance of teboroxime was modeled and found to be biexponential over 1 hr. A significant difference in myocardial clearance between the normal and stenosed zones (t1/2 = 4.5 +/- 0.9 min versus 10.2 +/- 2.6 min, respectively; p0.05) was observed for the first exponential phase (the first 5 min following initial uptake), but not for the second exponential phase (t1/2 = 160.7 +/- 35.9 min versus 140.4 +/- 27.4 min, respectively; p = ns). One hour fractional teboroxime blood clearance was 0.95 +/- 0.03, with most of the clearance occurring during the first 4 min. Gamma camera images of excellent quality demonstrated an initial defect with significant quantitative differential clearance over 1 hr. Thus, there are two phases of myocardial teboroxime clearance. During the early exponential clearance phase, teboroxime kinetics at rest may be able to differentiate between normal and hypoperfused myocardium.

Many children have struggled to cope with the traumatic experiences brought about by hurricanes Katrina and Rita. This article recounts how the authors intervened in the lives of children and families after the storms.

The use of incremental instead of absolute encoders for servomotor control involves the design of an interface to feed bidirectional counters. A robust method that the authors have implemented with a minimum number of components is presented. The method is also suitable for an all-software version that could be used in microcontroller applications with low CPU overhead. >

The locations of three cleavages that can occur in mouse 45S pre-rRNA were determined by Northern blot hybridization and S1 nuclease mapping techniques. These experiments indicate that an initial cleavage of 45S pre-rRNA can directly generate the mature 5' terminus of 18S rRNA. Initial cleavage of 45S pre-rRNA can also generate the mature 5' terminus of 5.8S rRNA, but in this case cleavage can occur at two different locations, one at the known 5' terminus of 5.8S rRNA and another 6 or 7 nucleotides upstream. This pattern of cleavage results in the formation of cytoplasmic 5.8S rRNA with heterogeneous 5' termini. Further, our results indicate that one pathway for the formation of the mature 5' terminus of 28S rRNA involves initial cleavages within spacer sequences followed by cleavages which generate the mature 5' terminus of 28S rRNA. Comparison of these different patterns of cleavage for mouse pre-rRNA with that for Escherichia coli pre-rRNA implies that there are fundamental differences in the two processing mechanisms. Further, several possible cleavage signals have been identified by comparing the cleavage sites with the primary and secondary structure of mouse rRNA (see W. E. Goldman, G. Goldberg, L. H. Bowman, D. Steinmetz, and D. Schlessinger, Mol. Cell. Biol. 3:1488-1500, 1983).

Data describing personality and behavior characteristics of emotionally disturbed children during and following treatment in a psychoeducational day treatment center are presented. Positive changes in social interactions, academic performance, intellectual performance, and self-esteem were documented after approximately 2 years of day treatment. These gains were for the most part maintained at the time of the first follow-up at 3 to 6 months following discharge and the second follow-up at 18 to 24 months following discharge. The discussion focuses on the process of change over time and on the interrelationships of the changes that occurred.

The habilitation of 34 thalidomide children, begun in 1963 at the Rehabilitation Institute of Montreal, involved the contribution of many medical and paramedical disciplines. These individual contributions are described.Habilitation of congenitally deformed children must be initiated at an early age. The early prescription of a prosthesis is desirable. Their care involves a broad range of services that must be continued over many years. Parents require support before they can accept the misfortune that has befallen them and their deformed child. Despite the necessity of frequent hospitalizations, children should be reared in a home setting. From their experience, the authors conclude that children born with malformations, and their parents, should be thoroughly evaluated and followed up for many years; and recommend that governments should finance programs for the complete habilitation of all children born with congenital malformations. National registries for the compulsory recording of birth deformities should also be established.

As a preparatory step towards the development of a complete habilitation program for children with congenital limb anomalies associated with maternal ingestion of thalidomide, the medical records of all patients with congenital limb anomalies referred to the Rehabilitation Institute of Montreal in the past decade were studied, and an examination and a thorough reassessment were made of 41 patients (21 males and 20 females). The medical and prosthetic aspects were dealt with in Part I of this paper. Part II describes, in a joint report, the results of psychiatric, psychological and educational assessments.There was no evidence of major emotional disorder in any of the patients, although conflicts were intensified by the presence of the physical anomaly. No relation was found between intelligence, emotional adjustment and disability. The patient's attitude towards his disability and prosthesis is definitely influenced by the degree of parental acceptance of the handicap and by the character of the emotional undertones in the total environment. In order to favour the occurrence of the healthiest modes of development in these children, the authors believe that the medical profession should be made fully aware of the physical and emotional problems which may arise after the birth of a deformed child. It is considered very important that the mother should receive psychotherapeutic support as soon as possible after the child is born.

As a preparatory step towards the development of a complete habilitation program for children with congenital limb anomalies associated with maternal ingestion of thalidomide, the medical records of all patients with congenital limb anomalies referred to the Rehabilitation Institute of Montreal in the past decade were studied, and an examination and a thorough reassessment were made of 41 patients (21 males and 20 females).In this paper, Part I, the medical and prosthetic aspects are dealt with and a form of management is described for each type of anomaly. The conclusions are reached that prosthetic fitting and training should be initiated very early in life and that co-operation of the parent is essential to successful habilitation of a child with congenital limb anomalies.