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Enhancing axon regeneration is a major focus of nerve injury research, and the quality of the surgical nerve repair plays a large role in the aggregate success of nerve regeneration. Additionally, exercise is known to promote successful axon regeneration after surgical nerve repair. In this study, we asked how exercise-induced nerve regeneration is affected when a transected nerve is repaired with or without fibrin glue. Fibrin glue repaired nerves exhibited greater vasculature within the tissue bridge compared to nerves that were intrinsically repaired. Fibrin glue repaired nerves also exhibited more robust axon regeneration after exercise compared to nerves that were not repaired with fibrin glue. When angiogenesis of the tissue bridge was prevented, exercise was unable to enhance regeneration despite the presence of fibrin glue. These findings suggest that the biological properties of fibrin glue enhance angiogenesis within the repair site, and a vascularized bridge is required for enhanced axon elongation with exercise. The combination of fibrin glue repair and exercise resulted in notable differences in vascular growth, axon elongation, neuromuscular junction reinnervation, and functional recovery. Fibrin glue should be considered as an adjuvant for nerve repair to enhance the subsequent efficacy of activity- and physical therapy-based treatment interventions.

There were a total of 12 documented Panax quinquefolius (American Ginseng) in the only known population in Louisiana in 1986. Our reassessment of the population in 2016 found 16 plants. We suggest that the long-term persistence of this tiny American Ginseng population indicates that simple matrix-population models may be overestimating quasi-extinction numbers and minimum viable populations, perhaps as a result of failing to sufficiently consider influences of environmental conditions. We further suggest that this, the southernmost documented population of the species in the US, has endured beyond expectation but remains at acute risk of extirpation and that any population-specific genes are at risk of loss if no intervention is made to protect the population.

The objective of this field study was to evaluate the effects of crop rotation (rice-rice and soybean-rice) and rice cultivar selection (one hybrid and two pure-line cultivars) across two consecutive growing seasons (2012 and 2013) on methane (CH 4 ) fluxes and emissions from rice grown in the drill-seeded, delayed-flood production system on a silt-loam soil. Weekly CH 4 fluxes were measured from flooding to harvest from 30-cm-diameter, enclosed-headspace chambers at the Rice Research and Extension Center near Stuttgart, Arkansas. Averaged over years, area-scaled season-long CH 4 emissions were greater ( P 4 -C ha − 1 from Taggart and Cheniere, respectively), which did not differ, than from the hybrid CLXL745 following soybean (72.2 kg CH 4 -C ha − 1 ). Averaged across years and cultivars, yield-scaled season-long CH 4 emissions were greater ( P 4 -C [Mg grain] − 1 , respectively). Averaged across years and crop rotation, yield-scaled season-long CH 4 emissions were 77% greater ( P 4 emissions provide valuable data for future estimates of CH 4 emissions from the drill-seeded, delayed-flood production system on a silt-loam soil among crop rotation-cultivar combinations to refine greenhouse gas emissions estimates and evaluate anticipated climate change.

Rice (Oryza sativa L.) plays a key role in sustaining global food security; however, rice production also accounts for a significant proportion of global methane (CH4) emissions, a major greenhouse gas involved in altering global climate. Many previous studies have quantified the proportion of CH4 emissions by independently evaluating factors such as soil texture and cultivars – an approach that has led to potentially biased estimates of their actual contribution to total emissions. Most of these studies have not considered the influence of the preceding crop or growing-season weather that could lead to a significant variation in carbon budgets. The main objective of this study was to identify the key edaphic, cultivar, and environmental factors and determine their proportional contributions towards CH4 emissions in direct-seeded, rice-based cropping systems. A multiple regression model was developed to quantify CH4 emissions as a function of temperature (both day and night independently and in combination) and other weather variables, soil (silt-loam-surface-textured Albaqualf and clay-surface-textured Epiaquert), cultivar (conventional and hybrid), and cropping system (rice-rice and soybean [Glycine max L.]-rice). Results showed that (i) the Albaqualf emitted 211% more CH4-C than the Epiaquert (P

Rice (Oryza sativa L.) production systems have a greater global warming potential than upland crops because of methane (CH4) emissions resulting from anaerobic conditions of the flooded soils. Differences in cultural practices, cultivar choice, previous crop/crop rotation, and in particular

Quantifying methane (CH4) emissions from cultivated rice (Oryza sativa L.) production in the field has received increased attention recently due to methane’s importance as a greenhouse gas. The enclosed-headspace chamber technique is the standard methodology for field assessments of trace gas emissions. However, to our knowledge, no direct comparisons of measured CH4 fluxes and emissions from field-grown rice among differing chamber sizes have been reported. Therefore, the objective of this study was to evaluate the effect of chamber size [15.2- and 30.4-cm inside diameter (id)] on CH4 fluxes and season-long emissions from rice grown on a clay soil in Arkansas. Chamber size did not affect (P > 0.05) CH4 fluxes on 10 sampling dates during the flooded portion of the rice growing season and only affected fluxes on one of four sampling dates after flood release. Total season-long CH4 emissions from optimally N-fertilized rice were 32.6 and 35.6 kg CH4-C ha&#451&#183season&#451, which did not differ, and from bare clay soil were 0.74 and 1.75 kg CH4-C ha&#451&#183season&#451, which also did not differ, from the 15.2- and 30.4-cm chambers, respectively. Chamber size (i.e., 15.2- or 30.4-cm id) did not result in differences in cumulative CH4 emissions from this flooded-rice study that was conducted on a Sharkey clay soil in northeast Arkansas. Results indicate that both 15.2- and 30.4-cm diameter chambers were similarly adequate for measuring CH4 fluxes and emissions from the clay soil investigated. The similarity in emissions results between chamber sizes also indicates that the 15.2-cm diameter chambers adequately facilitated the quantification of CH4 emissions in this study.

Multilayer actuators (MLAs) offer an increase of force per unit area, a reduction in power consumption, and a reduction in required driving voltages compared with singlelayer actuators. For example, switching from a single 0.5- or 1.0-μm layer of PZT to multiple 250-nm-thick layers would enable a 2/3 to 3/4 reduction in actuation voltage and an increase of 2 to 3 times in actuation force per area for a PZT MEMS switches and robotics. Efforts have been focused on developing actuators using four 250-nm-thick layers of PZT with a Zr/Ti ratio of 52/48 (i.e., the morphotropic phase boundary). The PZT films used a previously established method of achieving greater than 98% (001/100) oriented PZT by chemical solution deposition (CSD). By performing X-ray diffraction measurements between each layer, the texture within the films could be monitored during the growth process. To electrically measure the quality of the PZT multilayer stack, a series of six-sided capacitors were fabricated. The devices were connected in parallel with an average dielectric constant of 1150 for each PZT layer and an average total capacitance of 45 nF. In addition to capacitors, cantilever actuators were fabricated to measure the piezoelectric induced deformation. Comparisons with 100-μm-long cantilever between a single 1-μm-thick PZT and four 250-nm-thick layer PZT stack have shown comparable displacements of |3.7| μm and |4.0| μm, respectively, with an applied electric field of 10 V/μm across the film. These measurements on MLA PZT films demonstrate high piezoelectric coefficients that are suitable for tactile radio and milimeterscale robotic devices.

The effects of cultural practices on drill-seeded delayed-flood rice (Oryza sativa L.) production on methane (CH4) emissions are not well quantified. In Arkansas, rice is produced predominantly on loamy soils following soybean (Glycine max L.) as the previous crop, and hybrid rice has replaced a large percentage of pure-line cultivars in the past decade. Therefore, research was conducted during the 2012 growing season to assess the effects of previous crop (rice or soybean) and cultivar (standard-stature, semi-dwarf, and hybrid) on CH4 emissions on a silt-loam soil. A 30-cm-diameter chamber-based method was used to determine fluxes during the 2012 growing season. When soybean was the previous crop, fluxes were generally lower (P < 0.05) until heading, after which all fluxes decreased until flood release. Seasonal emissions differed based on previous crop and cultivar (P < 0.05). Area- and yield-scaled growing season emissions from rice following soybean were less (127 kg CH4-C ha; 13.7 kg CH4-C (mg grain)) than when rice followed rice (184 kg CH4-C ha; 20.5 kg CH4-C (mg grain)). Hybrid rice emitted less (111 kg CH4-C ha; 11.1 kg CH4-C (mg grain)) than semi-dwarf (169 CH4-C ha; 18.3 kg CH4-C (mg grain)) or standard-stature rice (186 kg CH4-C ha; 21.9 kg CH4-C (mg grain)), which did not differ. Thus, results indicated decreased emissions when soybean was the previous crop and when the hybrid cultivar was grown. The incorporation of factors known to influence CH4 emissions (i.e., previous crop, cultivar, and yield) will improve estimates of the carbon footprint of rice.

This paper investigates total ionizing dose (TID) effects on the piezoelectric properties of lead zirconate titanate (PZT). The capacitance and contact voltage of thin-film, PZT-based relays were measured following incremental 60Co TID irradiations. The devices were held in several different bias conditions, during exposure. The direction of the biasing electric field during exposure, along with the polarization prior to exposure, has a measurable impact on post-irradiation operating voltage of the relay. In all cases, the switching voltage, as obtained via the peak values in a capacitance versus voltage sweep, shifted in a direction that would minimize the switching electric field in the direction of pre-exposure polarization. These effects were observed to be both significantly greater than the shifts experienced by a set of control samples, as well as reversible via aging at room temperature. The devices display remarkable robustness, operating during active TID exposure [dose rate = 855.6 rad(Si)/s], failing at a TID greater than 15 Mrad(Si).

Rice (Oryza sativa L.) is a semiaquatic plant produced globally as a staple food crop under flooded-soil conditions for the majority of the time it is actively growing. Prolonged flooding results in the rapid depletion of oxygen and renders the soil highly anaerobic and reduced, both of whic

Diboration of the styrylboronate esters (E)-p-R–C6H4–CHCH–Bcat (1) (R=H, (1a) MeO (1b); cat=1,2-O2C6H4), with B2cat2 in the presence of a variety of rhodium phosphine catalysts gives predominantly either p-R–C6H4–CH2C(Bcat)3 (2), which contains three boronate ester groups on one carbon atom, or its isomer p-R–C6H4–CH(Bcat)CH(Bcat)2 (3). The formation of 2 apparently involves regiospecific insertion of the vinylboronates into a Rh–B bond followed by β-hydride elimination, another regiospecific insertion of the 2,2-vinyl bis(boronate) into the remaining Rh–B bond followed by C–H reductive elimination leading to 2,2-diboration and a 2,1-hydrogen shift. Wilkinson's catalyst (7) gives the highest yields of 2 with 75 and 71% yields from 1a and 1b, respectively, while [Rh(COE)2(μ-Cl)]2 (10) with two equivalents of P(o-tol)3 gave 3 in highest yield with 50 and 49% from 1a and 1b, respectively. The crystal structure of (E)-p-MeO–C6H4–CHCH–Bcat shows the molecule to be essentially planar, with the phenyl ring twisted slightly out of the plane. The tris(boronate) p-MeO–C6H4–CH2C(Bcat)3 crystallises with two independent molecules in the unit cell, which differ in the rotational orientation of the phenyl ring in relation to the catecholate groups; the latter are arranged in a propeller-like fashion.

A series of neutral pyridyl adducts involving the strong Lewis acids BF3 and B(C6F5)3 has been prepared, and their second-order nonlinear optical coefficients (EFISH method) have been examined. The formation of the pyridyl−boron bond leads to enhancement of the dipole moments and second-order NLO coefficients (β and β(0)). Reactions of DMAP (4-Me2N−C5H4N) with BH3, BF3, and B(C6F5)3 give the corresponding neutral pyridine adducts DMAP·BH3 (orthorhombic, Pbca, a = 9.6914(7) A; b = 11.7173(9) A; c = 22.718(2) A; V = 1622.4(5) A3; Z = 8; p = 1.114 g cm-3), DMAP·BF3 (orthorhombic, Pbca, a = 10.430(3) A; b = 8.111(2) A; c = 20.295(7) A; V = 1717.0(9) A3; Z = 8; p = 1.470 g cm-3), and DMAP·B(C6F5)3 (orthorhombic, Pbca, a = 12.322(1) A; b = 20.556(2) A; c = 28.455(3) A; V = 7207.4(14) A3; Z = 8; p = 1.508 g cm-3). Reactions of Me2N−4-C6H4−CHCH−C5H4N, MeO−4-C6H4−CHCH−C5H4N, and Me2N−4-C6H4−C⋮C−C5H4N with BF3 and B(C6F5)3 result in materials that are highly luminescent and incorporate structural features that are ...

Litigation is useful for both enforcing existing rights, and for showing the implications of legal principles derived from other types of cases to tobacco products. Thus: Because civil litigation does not require the active participation of either the executive or legislative branches of government, it may produce successes in tobacco control even where these other branches will not act. Thus although police may rarely enforce laws against selling cigarettes to minors, the expense and adverse publicity facing retailers sued for violating consumer protection laws as a result of such sales may cause these retailers to correct their practices.7 Whereas the influence of the tobacco industry may obstruct efforts …

Background —The merits of retaining the subvalvular apparatus during mitral valve replacement for chronic mitral regurgitation have been demonstrated in numerous clinical and laboratory investigations. In this preliminary report, we analyzed the early effects of complete versus partial chordal preservation on left ventricular mechanics. Methods and Results —Fifty patients undergoing isolated surgical correction of mitral insufficiency were prospectively randomized to either total or partial chordal-sparing mitral valve replacement. Of the first 19 patients studied, 8 had preservation of the posterior leaflet only, and 11 had complete preservation of all chordal structures. A comparison group consisted of 6 patients who had primary mitral valve repair. Echocardiography was performed preoperatively and at discharge from the hospital to determine dimensions, wall stress, and ejection fraction. Preservation of the posterior leaflet only resulted in a reduction in end-diastolic volume, an increase in end-systolic volume ( P =0.058), a rising trend in end-systolic stress, a decrease in long-axis fractional shortening, and a fall in ejection fraction from 0.68±0.16 to 0.46±0.19 ( P =0.001). Although patients who had preservation of all chordal structures also had decreased end-diastolic volume, long-axis fractional shortening, and ejection fraction (0.60±0.13 to 0.52±0.07, P =0.01), end-systolic stress fell and end-systolic volume decreased instead of increased. Compared with the posterior leaflet preservation group, those in the group with completely preserved chordal structures had a larger decline in end-diastolic volume and smaller decreases in long-axis fractional shortening and ejection fraction. Changes in end-systolic volume and stress were also statistically different between the 2 cohorts. No differences were detected between the group with total preserved chordal structures and the mitral repair group in any of the measured parameters. Conclusions —Compared with posterior chordal preservation only, complete retention of the subvalvular apparatus during mitral valve replacement resulted in improved ejection performance and smaller chamber volumes due to reduced systolic wall stress. These hemodynamic advantages are comparable to those observed with primary mitral reconstruction.

Background —Stentless aortic valves were designed to provide a more physiological flow pattern and lower transvalvular gradient, which may have an important bearing on postoperative left ventricular function and remodeling. In this study, we prospectively analyzed the 5-year clinical results with the Freestyle valve (Medtronic, Inc) and its hemodynamic performance by serial echocardiography. Methods and Results —Between January 1993 and August 1997, 95 patients with a mean age of 75 years underwent aortic valve replacement with the Freestyle prosthesis. Sixty-four percent of patients received valves ≤23 mm, and 37% had concomitant coronary artery bypass grafting. Average follow-up was 44±18 months (mean±SD), and echocardiography was performed preoperatively, at discharge, at 3 to 6 months, and annually thereafter. The 30-day operative mortality rate was 3%, with an overall actuarial survival rate of 80±6% (mean±SEM) at 5 years. Of the 10 late deaths, only 2 were cardiac related, thereby yielding a freedom from cardiac mortality of 94±3% after 5 years. No patient required reoperation on the aortic valve for any reason, including structural degeneration, nonstructural dysfunction, or prosthetic valve endocarditis. There were 9 thromboembolic and 3 anticoagulant-related bleeding events, none of which was fatal. The actuarial freedom from valve-related morbidity and mortality was 79±4% at 5 years. Hemodynamically, the mean transvalvular gradient significantly decreased after valve replacement and was reduced further by 41% by 6 months with a corresponding increase in effective orifice area. Left ventricular mass index fell to 75% of the preoperative value by 2 years. Conclusions —The Freestyle stentless valve can be implanted safely in the elderly with excellent midterm clinical results. It has superb hemodynamics in terms of residual transvalvular gradient, effective orifice area, and regression of left ventricular hypertrophy.

Background . Due to improved operative techniques, myocardial preservation, and perioperative care, open heart procedures are now being performed in older and sicker patients. As a result, the quality of life has become an important issue in the decision making process. Methods . Between January 1993 and October 1994, 604 patients above 65 years of age who underwent non-emergent open heart operations were followed prospectively over a 2-year period. The Health Status Questionnaire forms were distributed to all patients preoperatively and to hospital survivors at 3, 12, and 24 months. The questionnaire contains 36 questions and is divided into eight categories. Follow-up was 100% complete with 99.6% of questionnaires returned. Results . Significant quality of life improvements were noted in all categories after surgery. After reaching a peak at 12 months, there were small, but significant declines in scores relating to physical health and health perception at 24 months. In contrast, measurements for mental attributes continued to increase with time. By multivariate analysis, diabetes, older age, and female gender had a relatively adverse influence on quality of life despite improvement after operation. Similarly, patients with chronic obstructive pulmonary disease or having redo operations had lower health perception with some physical limitations. While procedure type (coronary artery bypass grafting) was associated with preoperative bodily pain, congestive heart failure symptoms were not an independent factor affecting quality of life. Conclusions . Quality of life improves with cardiac surgical interventions in this studied age group and should not be denied even in the elderly population.

Background: Many studies have demonstrated the superior hernodynamics of stentless porcine aortic valves compared to stented valves. This article describes the operative techniques and reviews our 5-year experience with the Medtronic Freestyle stentless valve. Methods: Between January 1993 and November 1997, 95 patients underwent implantation of the Medtronic Freestyle valve at a mean age of 76 years. All patients were seen at 6 months, 1 year, and annually thereafter for clinical assessment and Doppler echocardiography. Results: There were three operative and ten late deaths (two cardiac and eight noncardiac). Three strokes and four transient ischemic attacks occurred in the follow-up period. Four patients had bacteremia that was treated successfully with antibiotics. No patient required reoperation for valve-related problems. Serial echocardiograms revealed a decrease in mean systolic gradients across the valve during the first year and an increase in effective orifice areas. Ninety-one percent of patients had no, or trace, aortic insufficiency at the time of discharge and this has not increased over time. Conclusion: The Medtronic Freestyle valve has excellent hemodynamics and good clinical results. In our experience, no patient has required reoperation in a 5-year follow-up.

Delinquency is a community problem. In the final analysis the means for its prevention and control must be built into the fabric of community life. This can happen only if the community accepts its share of responsibility for having generated and perpetuated paths of socialization that lead to sporadic criminal episodes for some youth and careers in crime for others. Studies of the causes of crime point to many individual and social pathologies that may find expression in deviant and criminal behavior. In a competent community, however, the opportunities and motivations for crime are controlled by the way its institutions are organized to respond to such threats to public safety. There is a willingness to experiment and improve the responsiveness of individual and family services, religious organizations, neighborhood groups, schools, recreational agencies, housing associations, employment markets, and juvenile justice agencies. The result is a communal context that is sensitive to the problems of growing up and possessed of the institutional capacity to respond appropriately.

Changes in secure care in Massachusetts juvenile correction over the last decade are understood in the context of the larger processes of reform and counterreform during the same period. The decision-mak ing process used for placing youths in secure care since 1978 is ex amined in more detail. Secure care as a statewide system caught up in a struggle over community-based correction is seen to reflect changes in the system as a whole.

The Center for Criminal Justice at the Harvard Law School is in the fifth year of a seven-year project to study the reforms undertaken by the Massachusetts Department of Youth Services to close training schools and substitute a diversified network of community-based correctional ser vices for youth. The following account outlines the research design of the project and presents preliminary findings to date. The Department is still consolidating its new system of public and privately purchased services. However, current indications based on six months of community expo sure following treatment reveal a significant decline in court appear ances and a greater positive response of youth to the new programs.

The authors raise three principal questions. First, what part should traditional training schools play in providing treatment for youthful offenders? Second, what is the relative effectiveness of community based in comparison to institutional treatment services for juvenile delinquents? Third, what problems arise in undertaking a radical change in policy and program from institution to community based services? To answer these questions, the Center for Criminal Justice at the Harvard Law School is evaluating the reforms undertaken by the Massachusetts Department of Youth Services since 1969. This article offers a preliminary report and description of the problems and progress of these reforms through three phases: the emergence of a mandate for reform, the reform of institutional treatment,and the move from institutions to community corrections. Interviews with staff and youth so far indicate a positive response of youth to the new programs.

Evaluation research on changing social service systems has been plagued with problems attributed to a lack of the stability required for rigorous evaluation designs. The authors present an alternative concep tualization scheme and model which permits evaluation to be done in such changing environments. The authors distinguish among sets, strategies, and programs and identify a time perspective in the use of evaluative criteria that focus on client relationships both within and outside programs. The model described should Permit research teams to address system administration concerns while at the same time taking advantage of the natural changing setting for testing theoretical proposi tions.

Two Lepidopterous leafminers have been observed on sweet potato at Koronivia, Fiji. The Gracillariid Acrocercops prosacta Meyr. is the more abundant species in most areas but populations of a Lyonetiid, Bedellia ipomoeae Bradley, reach damaging levels in fields sprayed with dieldrin for control of weevils (Cylas formicarius elegantulus (Summers) and Euscepes postfasciatus (Fairm.)). Such treatment is shown to reduce parasitisation of B. ipomoeae by a species of Apanteles near A. tapatapaoanus Fullaway and of A. prosacta, by another Braconid, a species of Mesocoelus near M. acrocercopsis Mues. However, outbreaks of B. ipomoeae could not be attributed to such reduction. Elimination of ant predation by the dieldrin sprays was more likely to have initiated the outbreaks.Sprays containing malathion, diazinon, or dieldrin killed larvae, but not pupae, of B. ipomoeae. Outbreaks of B. ipomoeae can probably be prevented by relying on cultural methods to control weevils or by intensifying insecticide applications to control both B. ipomoeae and the weevils.

Observations were made in Fiji on the ecology and control of two Delphacid planthoppers on rice, Sogatella furcifera (Horv.) and Nilaparvata lugens (Stål), the latter species having apparently been responsible for a devastating outbreak in 1959. The studies covered three rice seasons, 1961, 1962, and 1963, most of the research being done at Koronivia in the south-eastern part of Viti Levu. Samples were taken of planthoppers and their natural enemies in dryland (drilled) and wetland (transplanted) rice, as well as in rice seed-beds and areas with grass or mixed rice and grass. Insecticides applied at standard dosages were tested against the planthoppers.It was shown that S. furcifera was most common on young rice and that N. lugens predominated on older rice. Sogatella kolophon (Kirk.), long placed in the genus Sogata and confused with Sogatella furcifera, was abundant only in grassy areas. Populations of N. lugens and, to a lesser extent, of S. furcifera, were apt to reach damaging levels on transplanted rice growing in pools of standing water after a dry period. In drilled fields, the predatory Mirid Cyrtorhinus lividipennis vitiensis Usinger provided effective control by destroying eggs of N. lugens, and, by the time the rice was six months old, it usually outnumbered the females of N. lugens. Parasitism of planthopper eggs by Mymarids, Trichogrammatids, and Eulophids was very low. Parasitism of adults of S. furcifera and S. kolophon by Elenchid Strepsipterons averaged about ten per cent, and that by Dryinid wasps less than one per cent. Adults of N. lugens were virtually free from parasitism but were sometimes infected by fungi. Factors influencing outbreaks are discussed. These include the amount of rainfall, the type of cultivation, the age of the rice crop, the species composition of the planthopper populations, and the relative abundance of Cyrtorhinus.Insecticidal concentrates tested against both S. furcifera and N. lugens included malathion 50 per cent, emulsifiable concentrate, diazinon 20 per cent, e.c., Bogor 30 per cent, e.c., DDT 20 per cent, e.c., dieldrin 15 per cent, e.c., and Sevin 80 per cent, wettable powder. Dieldrin-resistant strains of N. lugens appeared during 1961, the third season in which dieldrin and BHC had been widely used. The other five materials gave good results, DDT being the least expensive and the most persistent, although it took more than 24 hours to reduce the plant-hopper populations. It was concluded that rice should be closely watched from its third to the end of its sixth month and that 50 oz. of DDT 20 per cent. e.c. in 50 gallons of water per acre, or an equivalent formulation of some other insecticide, should be sprayed on the rice stems if the planthopper density should exceed 10 per stem. Other possible measures for controlling rice planthoppers would include the introduction of Dryinid wasps parasitising N. lugens, the development of rice varieties resistant to planthopper attacks, and the use of controlled flooding in high-bunded fields, but on present evidence the first two appear to hold little promise of success.

During 1968, 1969, and 1970 populations of 2 gracillariid leafminers on white oak were sampled at the Brookhaven National Laboratory, Long Island, N. Y. In the lower stratum (0.5–3 m above the ground), densities (number per 1000 leaves) of the solitary leafminer, Cameraria hamadryadella (Clemens), ranged from 339 (1968) to 6 (1970); and those of the communalleafminer, C. cincinnatiella (Chambers), from 173 (1968) to 23 (1969). Various predators and at least 14 species of parasitoid wasps contributed to larval or pupal mortality of one or both leafminers, but more than 50% of the larvae in each generation died during the month after hatching from ill-defined processes associated with the condition of the leaves.

The 2 species of beetles used in this research are well suited for ecological comparisons. They occur together in areas generally undisturbed by human activity. The beetles are similar in that only one grub can develop in each seed of their leguminous hosts, but they differ with respect to their competitors and parasites. Finally, measurements of beetle density per pod can be made quite readily. The anthribid, Araecerus levipennis Jordan, is an Oriental species which became established in Hawaii during 1954 (Ford and Chilson 1955). The principal host of A. levipennis in Hawaii is koa hole, Leucaena glauca (L.) Benth., but it can also develop in the seeds of 2 other legumes, native koa, Acacia koa Gray, and kolomona haole, Cassia glauca Lam. Both koa haole and kolomona haole are Neotropical in origin. A. levipennis has been the subject of a comprehensive investigation by Sherman and Tamashiro (1956). The bruchid, Mimosestes sallaei (Sharp), is native to the Neotropical Region and the southern portions of the Nearctic Region. In 1918, it was found in Hawaii where its main hosts are 2 Neotropical legumes, klu, Acacia farnesiana (L.) Willd., and kiawe, Prosopis chilensis (Mol.) Stuntz (Bridwell 1919). Some observations on the bioniomics and mortality of M. sallaei have been made by Cushman (1911), Bridwell (1920), and Hinckley (1960).