A general multivariate latent growth model with applications in student careers Data warehouses

The evaluation of the formative process in the University system has been assuming an ever increasing importance in the European countries. Within this context the analysis of student performance and capabilities plays a fundamental role. In this work we propose a multivariate latent growth model for studying the performances of a cohort of students of the University of Bologna. The model proposed is innovative since it is composed by: (1) multivariate growth models that allow to capture the different dynamics of student performance indicators over time and (2) a factor model that allows to measure the general latent student capability. The flexibility of the model proposed allows its applications in several fields such as socio-economic settings in which personal behaviours are studied by using panel data.Comment: 20 page

Tree Function and Habitat Niche Partitioning in Tropical Forests: Implications for Responses to Environmental Change

Tropical forests possess exceptional levels of tree species richness but explaining this diversity has presented a long existing challenge. Habitat niche partitioning provides a hypothesis for species co-existence, whereby species avoid competitive exclusion by partitioning demands on multiple resources within an environment. However, limited understanding concerning how tree function is influenced by multiple environmental variables has limited the support for this hypothesis. This knowledge gap also limits our ability to predict how tropical forest tree communities will respond to environmental change, given multiple dimensions of a species’ niche are likely to be affected. In this thesis, I investigate the role of niche partitioning in supporting co-existence of species and the turnover of species across edaphic gradients, as well as how long-term changes to the environment from selective logging and drought affect niche space of tropical tree species. I use species distribution models and measurements of leaf physiological traits to determine the key dimensions of tree species’ niches in primary forests. In chapter 2 I demonstrate niche partitioning is strong within tropical forests with at least 60-86% of abundant species occupying their own unique niche. Species partition a wide range of abiotic environments, including soil nutrient, topographic and light environments, with greater environmental heterogeneity enhancing the scope for niche partitioning. Building on this, in chapter 3 I find that variation in nutrient availability explains more variation in leaf physiology and habitat preferences than light availability of species from the Dipterocarpaceae family that dominates South-East Asian forests. This highlights the importance of edaphic environments in structuring tropical forest communities. I also find different leaf nutrients are related to photosynthetic capacity in different forest types, revealing that multiple different nutrients may limit productivity and affect species distributions in tropical forests. Many tropical forest tree species are highly specialised with limited ability to adjust their traits between environments, underlining their potential vulnerability to environmental change. In chapter 4 I show seedlings from selectively logged Bornean forests have different community weighted mean trait values, with greater belowground investment in logged forests. These adaptations are sufficient to overcome soil stress and to maintain foliar nutrient concentrations. However, I show seedlings of species that dominate old-growth forests are less able to adapt their traits and experience elevated mortality rates in logged forests. I attribute this to greater soil nutrient limitation as they are unable to maintain leaf nutrient concentrations. Selective logging will therefore likely drive shifts in species composition towards greater dominance of earlier-successional species that have traits capable of surviving in disturbed environments. This could result in local-scale reductions in species diversity and functional diversity, which could reduce long-term resilience to environmental change. In contrast, in Chapter 5 I demonstrate small trees in Amazonian forests are able to respond to changes in their environment following long-term drought conditions. Following mortality of large canopy trees, small trees can respond to increased light availability even under reduced water availability by adjusting resource allocation and by increasing nutrient use efficiency. Despite evidence of resilience to long-term drought conditions, hyper-dominant species show a greater capacity to respond, which may further enhance the dominance of these species under future climates. In conclusion my results highlight the importance of habitat niche partitioning in structuring tropical forest tree communities and identify key environmental variables that determine species distribution and tree function. My results have important implications for the conservation and restoration of tropical forests under environmental change. Avoidance of environmental homogenisation and changes to as few environmental conditions as possible is likely to be important in maintaining high species diversity in tropical forests and to avoid increased dominance by few generalist species. Many current conservation and restoration projects focus on recovering vegetation, but my research highlights the additional need to maintain and restore soil environments, especially for the long-term persistence of highly specialist species

Seasonal variations in Greenland Ice Sheet motion : Inland extent and behaviour at higher elevations

Peer reviewedPreprin

The Soda Ban or the Portion Cap Rule? Litigation Over the Size of Sugary Drink Containers as an Exercise in Framing

The authors discuss the litigation over New York City’s “Portion Cap Rule,” which restricts the size of sugary drink containers. The authors provide a history of the rule, from its promulgation by the Board of Health to the Appellate Division’s decision invalidating the rule. The authors also comment on the dispute between the parties over how to frame the rule. Opponents of the rule characterize the measure as an unwarranted and unprecedented incursion of consumer choice and personal freedom. Proponents of the rule, including the City, view the rule as a modest measure intended to address obesity, a significant—even alarming—public health issue.The authors further discuss how the disagreement over how to frame this dispute illustrates the nature of the judgment the courts have made thus far. In determining whether the Board of Health has the authority to promulgate the rule, the courts have applied the four-factor test set out by the Court of Appeals in Boreali v. Axelrod in order to draw the “difficult-to-demarcate line” between permissible agency rulemaking and impermissible legislating. The authors contend that the courts\u27 application of the Boreali factors is not only discretionary, but some factors require nothing more than an exercise of classification or judgment. Thus far, the petitioners have been more successful than the City in persuading the courts that their view of the rule, and of the governing separation of powers principles, is correct

Factors Affecting Italian Ryegrass (\u3cem\u3eLolium multiflorum\u3c/em\u3e L.) Seed Distribution

Italian ryegrass (Lolium multiflorum L.) can be a productive and high-quality cool-season forage in the Southern Great Plains of the U.S.A, if it is managed to produce sufficient seed for effective reestablishment without compromising forage yield. Before the re-seeding dynamics of Italian ryegrass can be modeled an understanding of seed production, seed-shed, and seed dispersal is necessary. Here two factors affecting Italian ryegrass seed dispersal and distribution are examined – wind and cultivation practice (mowing and raking)

The Effect of Harvest Management on Forage Production and Self-Reseeding Potential of Italian Ryegrass (Lolium Multiflorum L.)

Italian ryegrass (Lolium multiflorum L.) (IRG) can be managed to produce a seed output sufficient for effective re-establishment, without compromising forage yield, it may provide an alternative to perennial cool-season grasses in the Southern Great Plains of the U.S.A. The reduction in cost of replanting and avoidance of cultivation offered by a self-seeding crop may be particularly useful in low-input production systems. We examined the effect of dates of initial harvest in spring and of partial harvests on forage yield, seed output and re-establishment of Italian ryegrass

Overseeding Unimproved Warm-Season Pasture with Cool- and Warm-Season Legumes to Enhance Forage Productivity

Overseeding forage legumes into existing warm-season pasture may help to reduce cool-season forage deficit on small and resource-limited small farms in the southern Great Plains of the United States. Unimproved warm-season grass pastures were overseeded with Korean lespedeza (Lespedeza stipulacea Maxim) were not overseeded with summer legume. These same plots were subsequently overseeded with hairy vetch (Vicia villosa Roth), crownvetch (Coronilla varia L.), black medic (Medicago lupulina L.) or ladino white clover (Trifolium repens L.) or, not overseeded with cool-season legume. Including lespedeza in a forage mixture increased total forage yield by an average of 15%, or 1700 kg ha-1 over 4 years. Overseeding with cool-season legumes provided a net benefit in total annual forage yield of 0.75 kg for each 1.0 kg of legume produced. Yield increases resulting from overseeding with hairy vetch or black medic were largely limited to the harvest season following sowing, while overseeded crownvetch or white clover provided limited short- to medium-term yield benefit. Improvement of low-productivity pasture resulting from legume introduction is likely to be slow and will require sustained management input to ensure the presence of a productive legume plant stand

Extraterritoriality and Comparative Institutional Analysis: A Response to Professor Meyer

In the last few years, the Supreme Court has applied the presumption against extraterritoriality to narrow the reach of U.S. securities law in Morrison v. National Australia Bank and international-law tort claims in Kiobel v. Royal Dutch Petroleum. By their terms, these decisions are limited to the interpretation of ambiguous federal statutes and claims under the Alien Tort Statute. A potential unintended consequence of these decisions, therefore, is that future plaintiffs will turn to common-law causes of action derived from state and foreign law, potentially filing such suits in state courts. These causes of action may include “human rights claims that arise from multinationals’ corporate activity,” as well as “a range of claims by U.S. citizens when they are injured abroad, such as when they are victims of foreign terrorist activity.” Professor Jeffrey A. Meyer’s important study (102 Georgetown L.J. 301, 314 (2014)) observes that debates about extraterritoriality are likely to turn to common-law causes of action, particularly as plaintiffs turn to these options in the wake of Kiobel. The thrust of Meyer’s article is a concern that future courts may consider applying the presumption against extraterritoriality to common-law claims, an outcome Meyer believes is unwarranted. On Meyer’s account, courts apply the presumption to statutes in order to avoid the “intrusion on the coequal regulatory authority of foreign sovereign states.” Meyer argues that several features of common law justify insulating it from the presumption: common law is “common” in its universal content, “commoner” in its bottom-up origins, and “constrained” in its development. Meyer’s article raises appropriate concern over an understudied issue. Recognizing that a focus on statutory interpretation has obscured the relevance of common law to many debates about extraterritoriality, Meyer rightly focuses on post-Kiobel (and post-Morrison) state-law claims. He also points out that conflict of laws has a role in these cases alongside the presumption against extraterritoriality. Meyer’s account is insufficient, however, when it comes to the comparison between common law and statutory law, and more importantly when it comes to the normative consequences of those comparisons for extraterritoriality. Meyer acknowledges many potential virtues of common law, but he does not consider judicial lawmaking in comparison to the legislative alternative. Even if Meyer is correct in his praise of common law, his analysis does not establish that all common-law causes of action deserve extraterritorial treatment (subject to choice-of-law) while statutory ones do not. A review of Meyer’s three features of common law — that it is “common,” “commoner” and “constrained” — reveals why these comparative institutional considerations are necessary for a complete picture of extraterritoriality, and indeed present perhaps the best hope for achieving Meyer’s goals of consistency, access to justice in U.S. courts, and regulatory harmony between co-equal sovereigns

On composite laminates with extensional anisotropy

The definite list of extensionally (membrane) anisotropic composite laminates with up to 21 plies is presented. The listings comprise of individual stacking sequences, which are characterized in terms of angle- and cross-ply sub-sequence relationships as well as the blend-ratio of unbalanced angle-plies. Dimensionless parameters, including lamination parameters, are provided, from which the extensional and bending stiffness terms are readily calculated and an assessment of the bending stiffness efficiency made for angle- and cross-ply sub-sequences. Comparisons are made between the structural response of extensionally-anisotropic laminates and laminates with both extensional- and bending-anisotropy; Initial- and post-buckling responses are considered at the panel level together with the static response of a complete wing-box structure

Cartographic research in EREP program for small scale mapping

The author has identified the following significant results. Skylab photography is suitable for producing planimetric maps with graphical representation of landform at scales up to 1:100,000. It cannot supply all the detail necessary for maps at this scale, but it may be used to produce a sound framework which can be completed by detail from other sources. Its principal cartographic use is for original mapping of undeveloped areas of the world, but it would also be useful for the revision of existing maps and for monitoring extensive urban changes