Effects of gallery density and species ratio on the fitness and fecundity of two sympatric bark beetles (Coleoptera: Curculionidae).

Interspecific interactions among tree-killing bark beetle species may have ecologically important consequences on beetle population dynamics. Using two tree-killing beetle species (Dendroctonus brevicomis and D. frontalis), we performed observational and experimental studies to verify cross-attraction and co-colonization under field conditions in northern Arizona and test the effects of gallery density and species ratio on response variables of average gallery length, offspring size (progeny fitness), and offspring production per centimeter gallery (fecundity). Our results show that both D. frontalis and D. brevicomis aggregate to pheromones synthesized de novo by D. brevicomis under field conditions and that galleries of both D. brevicomis and D. frontalis occurred together in the same region of a single host tree with significant frequency. In experimental manipulations of species ratios, the presence of conspecific beetles in the gallery environment strongly mediated fecundity, but D. frontalis was the only species that suffered negative impacts from the presence of heterospecific beetles in the gallery environment. Interactions did not result in any apparent fitness effects for progeny of either species, which suggests that multispecies aggregations and co-colonization may be a dominant ecological strategy in the region and result in niche sharing.

Biomimetic sensory feedback through peripheral nerve stimulation improves dexterous use of a bionic hand.

We describe use of a bidirectional neuromyoelectric prosthetic hand that conveys biomimetic sensory feedback. Electromyographic recordings from residual arm muscles were decoded to provide independent and proportional control of a six-DOF prosthetic hand and wrist-the DEKA LUKE arm. Activation of contact sensors on the prosthesis resulted in intraneural microstimulation of residual sensory nerve fibers through chronically implanted Utah Slanted Electrode Arrays, thereby evoking tactile percepts on the phantom hand. With sensory feedback enabled, the participant exhibited greater precision in grip force and was better able to handle fragile objects. With active exploration, the participant was also able to distinguish between small and large objects and between soft and hard ones. When the sensory feedback was biomimetic-designed to mimic natural sensory signals-the participant was able to identify the objects significantly faster than with the use of traditional encoding algorithms that depended on only the present stimulus intensity. Thus, artificial touch can be sculpted by patterning the sensory feedback, and biologically inspired patterns elicit more interpretable and useful percepts.

The Effects of Bean Leafroll Virus on Life History Traits and Host Selection Behavior of Specialized Pea Aphid (Acyrthosiphon pisum, Hemiptera: Aphididae) Genotypes.

Intraspecific specialization by insect herbivores on different host plant species contributes to the formation of genetically distinct "host races," but the effects of plant virus infection on interactions between specialized herbivores and their host plants have barely been investigated. Using three genetically and phenotypically divergent pea aphid clones (Acyrthosiphon pisum L.) adapted to either pea (Pisum sativum L.) or alfalfa (Medicago sativa L.), we tested how infection of these hosts by an insect-borne phytovirus (Bean leafroll virus; BLRV) affects aphid performance and preference. Four important findings emerged: 1) mean aphid survival rate and intrinsic rate of population growth (Rm) were increased by 15% and 14%, respectively, for aphids feeding on plants infected with BLRV; 2) 34% of variance in survival rate was attributable to clone × host plant interactions; 3) a three-way aphid clone × host plant species × virus treatment significantly affected intrinsic rates of population growth; and 4) each clone exhibited a preference for either pea or alfalfa when choosing between noninfected host plants, but for two of the three clones tested these preferences were modestly reduced when selecting among virus-infected host plants. Our studies show that colonizing BLRV-infected hosts increased A. pisum survival and rates of population growth, confirming that the virus benefits A. pisum. BLRV transmission affected aphid discrimination of host plant species in a genotype-specific fashion, and we detected three unique "virus-association phenotypes," with potential consequences for patterns of host plant use by aphid populations and crop virus epidemiology.

Plant Water Stress Affects Interactions Between an Invasive and a Naturalized Aphid Species on Cereal Crops.

In cereal cropping systems of the Pacific Northwestern United States (PNW), climate change is projected to increase the frequency of drought during summer months, which could increase water stress for crop plants. Yet, it remains uncertain how interactions between herbivore species are affected by drought stress. Here, interactions between two cereal aphids present in PNW cereal systems, Metopolophium festucae (Theobald) subsp. cerealium (a newly invasive species) and Rhopalosiphum padi L. (a naturalized species), were tested relative to wheat water stress. When aphids were confined in leaf cages on wheat, asymmetrical facilitation occurred; per capita fecundity of R. padi was increased by 46% when M. festucae cerealium was also present, compared to when only R. padi was present. Imposed water stress did not influence this interaction. When aphids were confined on whole wheat plants, asymmetrical competition occurred; cocolonization inhibited M. festucae cerealium population growth but did not affect R. padi population growth. Under conditions of plant water stress, however, the inhibitory effect of R. padi on M. festucae cerealium was not observed. We conclude that beneficial effects of cocolonization on R. padi are due to a localized plant response to M. festucae cerealium feeding, and that cocolonization of plants is likely to suppress M. festucae cerealium populations under ample water conditions, but not when plants are water stressed. This suggests that plant responses to water stress alter the outcome of competition between herbivore species, with implications for the structure of pest communities on wheat during periods of drought.

Restoring motor control and sensory feedback in people with upper extremity amputations using arrays of 96 microelectrodes implanted in the median and ulnar nerves.

OBJECTIVE: An important goal of neuroprosthetic research is to establish bidirectional communication between the user and new prosthetic limbs that are capable of controlling >20 different movements. One strategy for achieving this goal is to interface the prosthetic limb directly with efferent and afferent fibres in the peripheral nervous system using an array of intrafascicular microelectrodes. This approach would provide access to a large number of independent neural pathways for controlling high degree-of-freedom prosthetic limbs, as well as evoking multiple-complex sensory percepts. APPROACH: Utah Slanted Electrode Arrays (USEAs, 96 recording/stimulating electrodes) were implanted for 30 days into the median (Subject 1-M, 31 years post-amputation) or ulnar (Subject 2-U, 1.5 years post-amputation) nerves of two amputees. Neural activity was recorded during intended movements of the subject's phantom fingers and a linear Kalman filter was used to decode the neural data. Microelectrode stimulation of varying amplitudes and frequencies was delivered via single or multiple electrodes to investigate the number, size and quality of sensory percepts that could be evoked. Device performance over time was assessed by measuring: electrode impedances, signal-to-noise ratios (SNRs), stimulation thresholds, number and stability of evoked percepts. MAIN RESULTS: The subjects were able to proportionally, control individual fingers of a virtual robotic hand, with 13 different movements decoded offline (r = 0.48) and two movements decoded online. Electrical stimulation across one USEA evoked >80 sensory percepts. Varying the stimulation parameters modulated percept quality. Devices remained intrafascicularly implanted for the duration of the study with no significant changes in the SNRs or percept thresholds. SIGNIFICANCE: This study demonstrated that an array of 96 microelectrodes can be implanted into the human peripheral nervous system for up to 1 month durations. Such an array could provide intuitive control of a virtual prosthetic hand with broad sensory feedback.

White House Cases: psychiatric patients and the Secret Service.

Delusional visitors to the White House or other government offices (often seeking a personal audience with the President) are interviewed by the Secret Service and then sent to Saint Elizabeths Hospital if they are considered mentally ill and potentially dangerous to themselves or others. A review of the demographic characteristics and diagnoses of 328 of these "White House Cases" treated at the hospital between 1970 and mid-1974 showed that these patients were most commonly unmarried, white, and male, and most had a diagnosis of paranoid schizophrenia. Although 22% of this group have threatened some prominent political figure, to date none of this study's patients has attempted to assassinate any such government official.

Murder and assault arrests of White House cases: clinical and demographic correlates of violence subsequent to civil commitment.

The authors studied arrest records and clinical data on 217 persons formerly hospitalized as "White House Cases" because they were psychotically preoccupied with prominent political figures. Prior arrest for violent crime was the variable most strongly associated with arrest for violent crime after hospital discharge. Male gender and a history of weapons possession were also correlated with future violence. For those with prior violent crime arrests, hospital incidents requiring seclusion were also associated with later violence. For those without prior arrests, subsequent violence was associated with threats, living outside Washington, and command hallucinations. For those previously arrested for nonviolent crimes, only persecutory delusions were associated with later violence.

Wound coverage in the Achilles region.

Skin loss over the distal Achilles region regardless of cause presents a problem in reconstruction. A variety of techniques have been employed. These procedures are critically reviewed and the technique which has proven helpful at our institution is discussed. The latter procedure employs a local random pattern rotation flap which has the advantages of simplicity, brief hospitalization, predictability of success, and coverage with sensate skin that is not bulky.

Treatment of felons.

The pitfalls of traditional concepts in the management of a felon are reviewed. A more rational and uniformly successful method is detailed. This consists of a midvolar, longitudinal incision of the fat pad where the majority of abscesses point. Other incisions are reserved for the few cases in which maximal tenderness is shown elsewhere. An abscess should always be drained where it points. It has not been our intent in this report to discuss the problems of extension of infection beyond the closed space of the distal fat pad or to deal with paronychias and eponychias that simulate a felon by their extension.

In-home support for recovering alcoholic mothers and their families; the family rehabilitation coordinator project.

A program is described for training paraprofessional workers to aid recovering alcoholic mothers and their families to improve household organization and communication and to use community services.

Morbid obesity.

Weight loss following surgical intervention for morbid obesity leaves a redundancy of loose, amorphous skin. Contour surgery should be delayed at least one year following stabilization of weight loss to allow maximum skin contracture. If more than one procedure is contemplated, a sequence should be outlined with the patient to maximize the use of operating room time and minimize exposure to general anesthesia.

Malignant tumors of the upper extremity: 1971 to 1976.

A series of 31 patients who acquired malignancies of the upper extremity has been reviewed. Comments regarding suggested therapy are included.

Cocaine concentrations in the blood during rhinoplasty.

After applying 5% or 10% cocaine to the nasal mucosa, blood concentration were measured in 9 patients undergoing rhinoplasty and in 6 unoperated controls. The concentrations in the unoperated persons were lower than in those undergoing rhinoplasty, and lower concentrations were found after 5% solutions in both groups than in those exposed to 10% solutions. There was no correlation between the strength of the solution used and the degree of bleeding or the success of the anesthesia. One patient developed symptoms of toxicity within two minutes of a 5% cocaine application to his nasal mucosa. The cocaine concentrations in his blood were the highest seen in our studies, and we cannot explain this.

Inflammatory pseudotumor of the orbit. Case report.

A case report and a review of the literature of inflammatory pseudotumors of the orbit is presented. The lateral approach, using microsurgical technique, is described. The incidence of this primary granuloma is comparable to other orbital tumors, and the diagnosis is confirmed by histological study of a biopsy specimen. Surgical excision offers the best mode of treatment. Although steroids may help postoperatively, the prognosis is poorer if the tumors are large. Radiotherapy offers no benefit.

Soft-tissue expansion: concepts and complications.

Soft-tissue expansion complements existing reconstructive techniques and provides new vistas for the plastic surgeon. The technique finds use for overcoming a shortage of tissue, for obtaining skin with special desirable qualities, for creation of flaps otherwise not possible because of the resultant donor site or limited vascularity, for creation of flaps with functioning muscle and overlying soft tissue, and for minimizing flap donor-site problems. Careful planning should include patient counseling, optimum incision placement, and time for a leisurely, complete expansion. The surgery can often be performed under local anesthesia and expansion is tolerated well. Patients should be counseled that the incidence of major complications in an unselected series is 1 in 4 patients. Major complications, however, typically result in a delay in reconstruction and not tissue loss.

Soft-tissue expansion in the lower extremities.

Soft-tissue expansion enjoys ever-wider use, but to date an experience using this technique in the lower extremity has never been presented. We reviewed our first 16 patients to describe the indications and contraindications for the use of tissue expansion in the lower extremity. Guidelines evolved from study of the data. Soft-tissue expansion merits consideration for coverage of problem wounds, in preparation for removal of large benign lesions, and for the repair of contour defects. The operator should know that an open wound below the knee predicts a complication if soft-tissue expansion is attempted in that location. In the thigh, incisions can be confidently placed at the edge of the defect. In every location, large expanders should be chosen so that they are as long as or longer than the adjacent defect. The increase in circumference of the limb should be followed. Simple designs for advancement flaps usually work well. As our experience has grown, reconstruction using soft-tissue expansion in the lower extremity has become safer and the results more predictable through better patient selection and diligent monitoring of intraluminal pressures, even if only by ensuring that the patient is always comfortable. Soft-tissue expansion has a role in reconstruction of the lower extremity.

Host settling behavior, reproductive performance, and effects on plant growth of an exotic cereal aphid, Metopolophium festucae subsp. cerealium (Hemiptera: Aphididae).

The cereal aphid Metopolophium festucae subsp. cerealium (Stroyan) is a recent addition to North America, but little is known about this species in its exotic habitat. We surveyed aphid populations for 3 years (2011-2013) to investigate changes in aphid density in the Pacific Northwest United States. We tested aphid host settling preference and fecundity on eight grass species, four native grasses (bluebunch wheatgrass, blue wild rye, Idaho fescue, and rough fescue) and four cereal crops (corn, wheat, barley, and oat), and evaluated the effects of aphid feeding on plant biomass. Four important findings emerged: 1) aphid prevalence in sweep net samples increased from 2011 to 2012, but remained stable from 2012 to 2013; 2) aphids preferentially settled on wheat and avoided corn, but aphids did not discriminate between barley, oat, and native grasses; 3) aphid fecundity was high on wheat and barley, intermediate on oat and blue wild rye, low on Idaho fescue, rough fescue, and bluebunch wheatgrass, and aphids did not reproduce at all on corn; and 4) barley, corn, oats, Idaho fescue, and blue wild rye were not susceptible to aphid feeding damage, but wheat, rough fescue, and bluebunch wheatgrass were susceptible to aphid feeding damage. Our results suggest that wheat and barley are preferred by M. festucae cerealium, and that aphids reproduce most rapidly on these hosts and cause significant reductions in wheat but not barley growth. Also, M. festucae cerealium appears capable of surviving on native grasses, although only bluebunch wheatgrass and rough fescue were susceptible to aphid feeding damage.

Spatial and temporal characteristics of V1 microstimulation during chronic implantation of a microelectrode array in a behaving macaque.

OBJECTIVE: It has been hypothesized that a vision prosthesis capable of evoking useful visual percepts can be based upon electrically stimulating the primary visual cortex (V1) of a blind human subject via penetrating microelectrode arrays. As a continuation of earlier work, we examined several spatial and temporal characteristics of V1 microstimulation. APPROACH: An array of 100 penetrating microelectrodes was chronically implanted in V1 of a behaving macaque monkey. Microstimulation thresholds were measured using a two-alternative forced choice detection task. Relative locations of electrically-evoked percepts were measured using a memory saccade-to-target task. MAIN RESULTS: The principal finding was that two years after implantation we were able to evoke behavioural responses to electric stimulation across the spatial extent of the array using groups of contiguous electrodes. Consistent responses to stimulation were evoked at an average threshold current per electrode of 204 ± 49 µA (mean ± std) for groups of four electrodes and 91 ± 25 µA for groups of nine electrodes. Saccades to electrically-evoked percepts using groups of nine electrodes showed that the animal could discriminate spatially distinct percepts with groups having an average separation of 1.6 ± 0.3 mm (mean ± std) in cortex and 1.0° ± 0.2° in visual space. Significance. These results demonstrate chronic perceptual functionality and provide evidence for the feasibility of a cortically-based vision prosthesis for the blind using penetrating microelectrodes.

Multiple factors may influence the performance of a visual prosthesis based on intracortical microstimulation: nonhuman primate behavioural experimentation.

We hypothesize that a visual prosthesis capable of evoking high-resolution visual perceptions can be produced using high-electrode-count arrays of penetrating microelectrodes implanted into the primary visual cortex of a blind human subject. To explore this hypothesis, and as a prelude to human psychophysical experiments, we have conducted a set of experiments in primary visual cortex (V1) of non-human primates using chronically implanted Utah Electrode Arrays (UEAs). The electrical and recording properties of implanted electrodes, the high-resolution visuotopic organization of V1, and the stimulation levels required to evoke behavioural responses were measured. The impedances of stimulated electrodes were found to drop significantly immediately following stimulation sessions, but these post-stimulation impedances returned to pre-stimulation values by the next experimental session. Two months of periodic microstimulation at currents of up to 96 µA did not impair the mapping of receptive fields from local field potentials or multi-unit activity, or impact behavioural visual thresholds of light stimuli that excited regions of V1 that were implanted with UEAs. These results demonstrate that microstimulation at the levels used did not cause functional impairment of the electrode array or the neural tissue. However, microstimulation with current levels ranging from 18 to 76 µA (46 ± 19 µA, mean ± std) was able to elicit behavioural responses on eight out of 82 systematically stimulated electrodes. We suggest that the ability of microstimulation to evoke phosphenes and elicit a subsequent behavioural response may depend on several factors: the location of the electrode tips within the cortical layers of V1, distance of the electrode tips to neuronal somata, and the inability of nonhuman primates to recognize and respond to a generalized set of evoked percepts.