FORCES AFFECTING CHANGE IN CROP PRODUCTION AGRICULTURE

Agricultural Competitiveness, Crop Production, Agricultural Biotechnology, Agricultural Sustainability, Agricultural Inputs, Agricultural Profitability, Crop Production/Industries, Q10, Q12, Q13,

The Point of View of the Student in Attrition Research

Until the early 1970's, research into attrition among postsecondary students was largely aimed at establishing correlations between the characteristics the students brought with them to an institution and dropping out. Virtually all of this research was unguided by any explicit theoretical framework. With the work of Spady (1970; 1971), and that of Tinto (1975), a model was provided which became the theoretical foundation for most subsequent research into the problem. The model was based fundamentally on part of Durkheim's work on suicide, keying on the concept of integration. According to the model, those students who were integrated into the social and academic life of the institution were less likely to drop out, and the focus shifted to include not only "background" factors, but also the experiences of students after they were admitted to the institution. While creating the illusion of offering a clear theoretical framework, the key concepts of social and academic integration are only very loosely connected with the original Durkheimian idea. It is contended here that a firmer foundation for the development of an appropriate theoretical framework is more likely to arise out of a careful attempt to understand the actions of students in terms of the meanings things in their world have for them. Methodological techniques appropriate to this task are advocated, without denying the importance of many significant clues to be found in much of the current and past research in the field.Jusqu'au début des années 70, les recherches sur le décrochage scolaire au niveau postsecondaire visaient essentiellement à établir des corrélations entre le profil des étudiants à leur entrée dans l'institution et, d'autre part, leur décrochage. La presque totalité de ces recherches se faisait sans cadre théorique explicite. Les travaux de Spady (1970; 1971) et de Tinto (1975) créèrent un modèle qui servit de fondement théorique à la plupart des recherches ultérieures sur ce problème. Ce modèle s'appuyait essentiellement sur une partie des travaux de Durkheim sur le suicide, particulièrement sur le concept d'intégration. Selon ce modèle, les étudiants intégrés à la vie sociale et intellectuelle de l'institution étaient moins susceptibles de décrochage. Il y eut dès lors un déplacement d'accent pour inclure non seulement les facteurs «généraux» mais aussi les diverses expériences des étudiants admis dans les institutions en question. Les concepts-clés d'intégration sociale et intellectuelle créent l'illusion d'un cadre théorique clair mais ne se rapportent que de façon lointaine à l'idée originale de Durkheim. Nous posons ici que l'on peut établir un point de départ plus sûr en étudiant attentivement les actions des étudiants en fonction du sens que revêtent les éléments de leur vie. Nous recommandons différerentes techniques méthodologiques adaptées à cette entreprise sans pour autant nier l'importance de nombreux indices importants que nous livrent les recherches actuelles ou passées dans ce domaine

Cryogenic Infrared Radiance Instrumentation for Shuttle (CIRRIS 1A) Instrumentation and Flight Performance

The Cryogenic Infrared Radiance Instrumentation for Shuttle (C1IRRIS 1A) instrument, launched on the shuttle Discovery (STS-39) on 28 April 1991, was developed to characterize the phenomenology and dynamics of ionospheric processes. The primary objective of the CIRRIS 1A mission was to obtain spectral and spatial measurements of infrared atmospheric emissions in the spectral region between 2.5 and 25 jm over altitudes ranging from the Earth\u27s surface to 260 km. The primary sensors are a Michelson interferometer/spectrometer and a multi-spectral radiometer, which share a common high off-axis rejection telescope. The sensor/telescope complex is enclosed in a cryogenic dewar that is mounted in a dual-axis gimbal system. Excellent data were obtained from this mission, and preliminary analysis shows that all sensors performed well. This paper describes the experiment hardware, summarizes instrument performance during flight, and presents examples of significant results

Concentration and Source in Receiving Rations Fed to Newly Received Stressed Calves

Animal Nutritio

Leveraging OpenStack and Ceph for a Controlled-Access Data Cloud

While traditional HPC has and continues to satisfy most workflows, a new generation of researchers has emerged looking for sophisticated, scalable, on-demand, and self-service control of compute infrastructure in a cloud-like environment. Many also seek safe harbors to operate on or store sensitive and/or controlled-access data in a high capacity environment. To cater to these modern users, the Minnesota Supercomputing Institute designed and deployed Stratus, a locally-hosted cloud environment powered by the OpenStack platform, and backed by Ceph storage. The subscription-based service complements existing HPC systems by satisfying the following unmet needs of our users: a) on-demand availability of compute resources, b) long-running jobs (i.e., $> 30$ days), c) container-based computing with Docker, and d) adequate security controls to comply with controlled-access data requirements. This document provides an in-depth look at the design of Stratus with respect to security and compliance with the NIH's controlled-access data policy. Emphasis is placed on lessons learned while integrating OpenStack and Ceph features into a so-called "walled garden", and how those technologies influenced the security design. Many features of Stratus, including tiered secure storage with the introduction of a controlled-access data "cache", fault-tolerant live-migrations, and fully integrated two-factor authentication, depend on recent OpenStack and Ceph features.Comment: 7 pages, 5 figures, PEARC '18: Practice and Experience in Advanced Research Computing, July 22--26, 2018, Pittsburgh, PA, US

A new diagnostic to separate line emission from star formation, shocks, and AGNs simultaneously in IFU data

In the optical spectra of galaxies, methods for the separation of line emission arising from star formation and an additional hard component, such as shocks or active galactic nuclei (AGNs), is well-understood and possible with current diagnostics. However, such diagnostics fail when attempting to separate and define line emission which arises from shocked gas, and that arising from AGNs. We present a new three-dimensional diagnostic diagram for integral field unit data which can simultaneously separate the line emission amongst star formation, shocks, and AGNs within a galaxy. We show that regions we define as AGN-dominated correlate well with the hard X-ray distribution in our test case NGC 1068, as well as with known regions of AGN activity in NGC 1068. Similarly, spaxels defined as shock-dominated correlate strongly with regions of high-velocity dispersion within the galaxy.Parts of this research were conducted by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3Dimensions (ASTRO 3D), through project number CE170100013

Acute Stretching Effect on Hamstring Muscle Stiffness using Elastography

Having first been introduced in the 1990s, shear wave elastography (SWE) has more recently been used to investigate intrinsic muscle stiffness. While studies have shown SWE to be an effective way of determining muscle stiffness, few have been conducted to measure the effects of stretching on the hamstring muscles. PURPOSE: to determine if there is a measurable difference of hamstring muscle stiffness with acute stretching using ultrasound elastography. METHODS: 16 subjects participated in this study (11 men and 5 women). Mean age 23.4 ± 2.6yrs for men and 21.2 ±1.5 for women. Mean height (cm) is 180.3± 4.7 for men and 172.7±2.5 for women. Mean weight (kg) is 76.8±9.7 for men and 70.0±14.9 for women. Participants lay supine and positioned to 90° hip and 90° knee flexion. Each participant came in for two sessions that consisted of (1) static stretching and (2) PNF stretching protocols. Maximum ROM of the knee joint, force, and muscle stiffness of the biceps femoris (BF), semimembranosus (SM) and semitendinosus (ST) were recorded both before and 1 minute after stretching. RESULTS: After accounting for age, weight and height, there was no significant difference between the use of static and PNF stretching techniques on either velocity (p= 0.4805) or kPa (p=0.5423) stiffness values. Both static and PNF stretching resulted in significant reductions in both velocity and kPa stiffness (pCONCLUSION: Stiffness as measured using SWE decreases following an acute stretching session for both static and PNF stretching techniques. This suggests alterations to intrinsic muscle characteristics beyond just “stretch tolerance” as suggested in previous literature. Changes in both ROM and force also support this claim. Further research on retention of decreased stiffness are needed as acute stretching has previously been shown to be temporary. Longer term stretching studies to determine if intrinsic muscle stiffness changes models plastic deformation are also needed and may help better elucidate duration and stretch technique differences

Comparison of Gastrocnemius Shear Wave Elastography Stiffness Over 5 Different Zones

A few studies report that shear wave elastography (SWE) is a reliable method of measuring gastrocnemius muscle stiffness. To date there are no studies assessing variance in stiffness measures at different locations on the muscle. This led us to ask whether the spot at which gastrocnemius stiffness is measured matters. PURPOSE: To determine if measurement site on the medial and lateral gastrocnemius affects SWE stiffness values. METHODS: Twelve subjects (3 men, 9 women) completed this study (Mean age is 23.0 (SD = 1.0) for men and 21.7 (SD = 2.0) for women (t p = 0.3035). Mean height (cm) is 179.5 (SD = 2.9) for men and 167.1 (SD = 7.8) for women (t p = 0.0256). Mean weight (kg) is 74.9 (SD =10.4) for men and 62.5 (SD = 9.7) for women (t p = 0.0892). Subjects wore shorts and lay prone on a treatment table with their bare feet hanging off the edge of the table. Ultrasound images to confirm borders of the medial and lateral gastrocnemius were confirmed and marked. SWE of both the Medial head (MG) and lateral head (LG) were taken with each head area divided into 4 zones (1=superior medial, 2=superior lateral, 3=inferior medial, 4= inferior lateral). A fifth zone was collected at the center of the muscle at 70% of the length of the lateral malleolus to lateral femoral epicondyle. All 5 points were assessed for SWE in both a relaxed and neutral (900) ankle joint position. Three separate elastogram frames were used to calculate muscle stiffness using both the velocity (m/s) and young’s modulus model (kPa) utilizing an overall area analysis for each. RESULTS: MG velocity and kPa values were significantly greater than LG in the relaxed and neutral positions (pCONCLUSION: MG stiffness is greater than LG regardless of position while intrinsic stiffness of MG increases more relative to LG when placed in neutral. Measurement of stiffness is best represented at the center of the muscle belly in the neutral position, but zones 2,3 and 5 produce similar stiffness values in the relaxed position