Pathogenicity of the root-knot nematode Meloidogyne javanica on potato

Host–parasite relationships and pathogenicity of Meloidogyne javanica on potatoes (newly recorded from Malta) were studied under glasshouse and natural conditions. Potato cvs Cara and Spunta showed a typical susceptible reaction to M. javanica under natural and artificial infections, respectively. In potato tubers, M. javanica induced feeding sites that consisted of three to four hypertrophied giant cells per adult female. Infection of feeder roots by the nematode resulted in mature large galls which usually contained at least one mature female and egg mass. In both tubers and roots, feeding sites were characterized by giant cells containing granular cytoplasm and many hypertrophied nuclei. Cytoplasm in giant cells was aggregated alongside the thickened cell walls. Stelar tissues within galls appeared disorganized. The relationship between initial nematode population density ( P ) [0–64 eggs + second-stage juveniles (J2s) per cm 3 soil] and growth of cv. Spunta potato seedlings was tested under glasshouse conditions. A Seinhorst model [ y = m + (1 − m ) z ( P − T ) ] was fitted to fresh shoot weight and shoot height data of nematode-inoculated and control plants. Tolerance limits ( T ) for fresh shoot weight and shoot height of cv. Spunta plants infected with M. javanica were 0·50 and 0·64 eggs + J2s per cm 3 soil, respectively. The m parameter in that model (i.e. the minimum possible y -values) for fresh shoot weight and shoot height were 0·60 and 0·20, respectively, at P = 64 eggs + J2s per cm 3 soil. Root galling was proportional to the initial nematode population density. Maximum nematode reproduction rate was 51·2 at a moderate initial population density ( P = 4 eggs + J2s per cm 3 soil).peer-reviewe

The single scattering phase functions of Jupiter's clouds

The determination of the single scattering phase functions of Jupiter's clouds and a thin upper haze by Tomasko et al. was refined and extended to seven latitudes in blue and red light. The phase function is well-constrained by the Pioneer 10 and 11 photometric data sets. Multiple scattering models were computed to match the limb darkening at each latitude at up to 15 phase angles from 12 deg to 151 deg. Ground-based observations were used for absolute calibration and to extend the data to lower phase angles. The phase functions were parameterized using the double Henyey-Greenstein function. The three Henyey-Greenstein parameters and the single scattering albedo were determined using a non-linear least squares method for the haze and the clouds below. The phase functions derived for the northen zone and belt are remarkably similar to the phase functions of the corresponding regions in the south, with most of the differences in brightness of the northern and southern features resulting from minor differences in single scattering albedo. Analysis of the Equatorial Region is complicated by the presence of numerous small features, but the phase function required is generally similar to that seen in the more homogeneous regions. Details of the phase functions of the haze and clouds are presented, and the differences between the cloud phase functions at low and high latitudes in red and blue light are discussed

Characterization and analysis of azimuthally sensitive correlations

A unified framework for describing the azimuthal dependence of two-particle correlations in heavy-ion collisions is introduced, together with the methods for measuring the corresponding observables. The generalization to azimuthal correlations between more than two particles is presented.Comment: 7 pages; talk given at Hot Quarks 2004, Taos (NM), July 18-24,200

The utilization of perceived needs importance in explaining and predicting responsiveness to organizational inducements

The concern over attraction and retention strategies in organizations has been widely acknowledged through the voluminous amount of research. As functions of human resources management (HRM), the emphasis in utilizing effective attraction and retention strategies cannot be ignored due to their importance to the firm\u27s overall performance. In meeting this concern, inducements have been recently mentioned to be the missing link in providing more effective recruitment and retention strategies. Inducements are deliberate modifications of a job characteristic or the work environment, including benefits for the sole purpose of enhancing the attractiveness of a job to potential applicants and maintaining that attraction to minimize the intention to leave (turnover). The purpose of this dissertation is to reveal the particular inducements that are important to the lower-level maquiladora workers in Mexico. By way of the inducements mentioned, needs were to be discovered for the purpose of attracting potential employees and more importantly reducing turnover. The needs theories by Maslow, Herzberg, and McClelland were used as a theoretical framework in explaining the inducements and needs of the lower-level workers in maquiladoras in Mexico. A qualitative field study was conducted to test propositions in the discovery of lower-level maquiladora workers\u27 needs as well as their “intention to stay”. Semi-structured interviews with open-ended questions were used in gathering responses from lower-level maquiladora workers. Utilizing content analysis and logistic regression, the findings indicate that this particular level of workers are likely to stay due to relationship-oriented inducements, work performance-related inducements, extrinsic and more visible inducements, and most importantly, inducements that satisfy their basic needs. Also, lower-level maquiladora workers are more likely to leave their jobs if they are discontent with contingent inducements. Through the inducement categories the development of the needs of lower-level maquiladora workers resulted in the development of the following needs: need for basic necessities, need for order/stability, need for patronage, need for development/improvement, and need for relationships. In comparing these needs with the classic needs, lower level needs are overwhelmingly “forgotten” and not satisfied by maquiladora management. For maquiladora management focused on increasing retention rates, this dissertation offers suggestions that may be considered in developing adequate human resource management practices for this level of maquiladora workers. For the academic community it provides the strategies in contributing to this growing theme in maquiladora literature where the focus lies in management principles contingent on the worker\u27s culture and background

Changing Criteria: What Decision Processes Reveal about Confidence in Memory

Source memory is our ability to relate central information (the “item”) to the context (the “source”) in which it was learned or experienced. People are often highly confident in their source judgements even when this information is incorrectly recalled. Past work has aimed to explain why source errors made with high confidence occur with a framework called the Converging Criteria (CC) account. The CC account posits that item memory can interact with source memory by altering decision criteria as item confidence increases, increasing the probability of a high confidence source judgement. This prediction differs from alternate models, like the Fixed Criteria (FC) account, where decision criteria are not expected to change with item confidence. The current study not only tests the implications of the CC account, but contrasts it to the predictions of the FC account relative to item memory, item confidence, and source discriminability, using existing data from 12 recognition memory experiments. We use a Bayesian Hierarchical model to estimate a key metric called the Item Confidence Effect (ICE) - the change in the proportion of source errors made with high confidence as item confidence increases. Results show a positive ICE, demonstrating that the proportion of source errors made with high confidence increases with item confidence, as predicted by the CC account. In the context of memory, this evidence shows that decision processes can influence behavior, regardless if evidence in memory supports it or not

Undrained shear behavior and critical state analysis of mixed mine waste rock and tailings

2019 Summer.Includes bibliographical references.The objectives of this study were to (i) evaluate the undrained shear behavior of mine tailings and a tailings-dominated mixture of filtered tailings and waste rock (i.e. GeoWaste), (ii) identify the critical state of each material, and (iii) assess the impact of waste rock inclusions on the critical state of tailings. Mine tailings and waste rock were collected from an active mine where GeoWaste is being considered as a potential solution for mine waste management. GeoWaste was prepared at a mixture of 1.2 parts waste rock to 1 part tailings, by dry mass, which was a relevant mixture ratio for field implementation. Consolidated undrained (CU) triaxial compression tests were conducted on pure tailings and GeoWaste. Large-scale triaxial compression tests were conducted on 150-mm-diameter GeoWaste specimens, and 38-mm-diameter triaxial tests were conducted on tailings prepared to three initial conditions: filtered tailings that represented field conditions, dense filtered tailings, and paste tailings. Triaxial compression tests were conducted at effective confining pressures (σc') ranging between 20 and 500 kPa. Filtered tailings prepared to represent field conditions yielded contractive, strain-hardening behavior. Dense filtered tailings exhibited strain-hardening behavior, net positive pore pressure, and a transition from contractive to dilative tendencies. Paste tailings exhibited modest strain-hardening behavior. GeoWaste exhibited strain-hardening, contractive behavior, and a modest transition from contractive to dilative behavior was observed at σ'c = 500 kPa. The undrained shear behavior of GeoWaste was comparable to filtered tailings at σ'c = 50 kPa and 100 kPa. However, undrained shear behavior of GeoWaste at σʹc = 500 kPa changed related to tailings, which was characterized by a larger deviator stress and lower excess pore pressure. This GeoWaste behavior indicated improved shear resistance compared to filtered tailings, which was attributed to (i) inter-particle reinforcing effects between the waste rock particles within a tailings-dominated structure and (ii) densification of the GeoWaste structure. Shear strength parameters were calculated from the slope of a composite Kf Line for each material. Filtered tailings prepared to represent field conditions, and dense filtered tailings yielded effective tangent friction angle (φ't) = 33°, and paste tailings yielded φ't = 32°. Similarity in φ't between the three tailings prepared with different initial specimen characteristics was attributed to similar void ratios at the end of consolidation under a given σʹc. GeoWaste yielded φ't = 32°. Although composite φ't were similar between tailings and GeoWaste, the secant friction angles of GeoWaste increased with increasing σʹc, whereas the opposite trend was observed for tailings. The addition of waste rock particles to tailings in a fine-dominated structure to increase the shear resistance relative to tailings as effective consolidation stress increased. An assessment was conducted between the critical state lines for tailings and GeoWaste to determine if the critical state line for tailings can represent critical state conditions in GeoWaste. An equivalent tailings void ratio (e*t) that can represent the tailings fraction within GeoWaste correlated with the critical state line for tailings. In this study, the e*t for GeoWaste was determined via optimizing a fitting parameter in the e*t equation to correlated with the critical state line for tailings. Although this evaluation suggests that the critical state line for the tailings can be used to represent critical state conditions in GeoWaste, additional work is needed to determine e*t a priori

Teachers\u27 Attitudes Towards Code Switching within a Bilingual Classroom

Within the United States, the number of native Spanish speaking students entering our schools has increased as the years have passed (Alanis & Rodriguez, 2008). Once they are in the school system, these students are labeled as English Language Learners (ELLs) or Limited English Proficient (LEP) with each entering with varying levels of the English language as well as their native language, Spanish. As more of these students come in, the more students our schools need to accommodate for their linguistic and academic needs. Thus, the purpose of bilingual programs is to develop students\u27 native language and develop their second language through the use of content. As these students are fortunate enough to develop both language skills, it is common to see bilingual students code switching within a single conversation. Some researchers and educators see code switching as a negative aspect while learning a language while others see it as a stage within the process of learning a new language. This thesis project investigates the functions of code switching, in what kinds of situations students code switch, and whether or not teachers see code switching as an asset or deficit