1,959 research outputs found
Policy implementation in housing: a study of the experience of Portsmouth and Derby, 1945-74
The germ of this thesis was born when the author read "Implementation" by J.A. Pressman and A. Wildavsky. This book stimulated the author's interest in the interpretation of Central Government policy by local authorities of differing political complexions.
This thesis reviews and researches the impact of the implementation of Central Government policy by local authorities and attempts to assess the reasons for divergence in policy between Conservative and Labour controlled authorities. The question posed is whether politics accounts largely or wholly for policy divergences, or whether it is other factors.
From the research undertaken by the author, it would appear that political complexion is only one factor in a very complex network of influences upon policy implementation. The thesis covers factors such as the personality of the actors involved, inter and intra departmental relationships, and professional linkages as well as the more traditional elements of local and central government interactions. The focus is on the implementation of housing policy in Portsmouth, a predominantly Conservative controlled authority, and Derby, a predominantly Labour controlled authority, during the period 1945 to 1974.Both authorities were faced by similar problems in the period reviewed, and yet each adopted its own distinct policy, as the skylines of the two cities reflect today
Policy implementation in housing: a study of the experience of Portsmouth and Derby, 1945-74
The germ of this thesis was born when the author read "Implementation" by J.A. Pressman and A. Wildavsky. This book stimulated the author's interest in the interpretation of Central Government policy by local authorities of differing political complexions.
This thesis reviews and researches the impact of the implementation of Central Government policy by local authorities and attempts to assess the reasons for divergence in policy between Conservative and Labour controlled authorities. The question posed is whether politics accounts largely or wholly for policy divergences, or whether it is other factors.
From the research undertaken by the author, it would appear that political complexion is only one factor in a very complex network of influences upon policy implementation. The thesis covers factors such as the personality of the actors involved, inter and intra departmental relationships, and professional linkages as well as the more traditional elements of local and central government interactions. The focus is on the implementation of housing policy in Portsmouth, a predominantly Conservative controlled authority, and Derby, a predominantly Labour controlled authority, during the period 1945 to 1974.Both authorities were faced by similar problems in the period reviewed, and yet each adopted its own distinct policy, as the skylines of the two cities reflect today
Clinal variation of dormancy progression in apricot
AbstractThe aim of this study was to determine the bud dormancy progression in apricot at different latitudes and altitudes. Six locations in regions with a Mediterranean climate in South Africa (SA) and Spain were chosen. The study was carried out during two consecutive years, 2007 and 2008, in SA and results were compared to those obtained in Spain in 2008. Locations ranged from low-chill areas, such as Ladismith and Villiersdorp in SA and CampotĂ©jar in Spain, to high-chill areas, such as Ceres in SA and Barranda in Spain. A number of apricot cultivars comprising the range of chilling requirements in both countries were selected. In addition, a second, parallel study was performed to evaluate the paradormancy progression in âPalsteynâ (SA) and âRojo PasiĂłnâ (Spain). Deeper dormancy was not observed in high-chill cultivars located in cold areas than in low-chill cultivars in warm areas. However, low-chill cultivars located in warm areas entered and released from dormancy earlier than high chill cultivars in warm areas. Thus, a clinal variation in dormancy progression under warm temperatures in apricot cultivars is suggested. The role of photoperiod and minimum temperatures is proposed to have a key role in dormancy onset. Paradoxically, an earlier maximum depth of dormancy was found in those areas with higher minimum temperatures at the end of summer. Before the beginning of winter, all cultivars showed an important increase of budburst rate, which indicated the end of endodormancy. Afterwards an ecodormancy period followed during winter, while chilling continued to accumulate. These results contrast with the assumed concept of the breaking of dormancy through chilling accumulation during winter and suggest a possible mediation by photoperiod in overcoming of dormancy. On the other hand, paradormancy exerted a reduction in budburst rate during dormancy entry, whereas decapitation increased the budburst rate throughout the dormant season, indicating interaction between different plant parts during this period
Living on the edge: Exploring the role of coastal refugia in the Alexander Archipelago of Alaska
Although islands are of longâstanding interest to biologists, only a handful of studies have investigated the role of climatic history in shaping evolutionary diversification in highâlatitude archipelagos. In this study of the Alexander Archipelago (AA) of Southeast Alaska, we address the impact of glacial cycles on geographic genetic structure for three mammals coâdistributed along the North Pacific Coast. We examined variation in mitochondrial and nuclear loci for longâtailed voles (Microtus longicaudus), northwestern deermice (Peromyscus keeni), and dusky shrews (Sorex monticola), and then tested hypotheses derived from Species Distribution Models, reconstructions of paleoshorelines, and island area and isolation. In all three species, we identified paleoendemic clades that likely originated in coastal refugia, a finding consistent with other paleoendemic lineages identified in the region such as ermine. Although there is spatial concordance at the regional level for endemism, finer scale spatial and temporal patterns are less clearly defined. Demographic expansion across the region for these distinctive clades is also evident and highlights the dynamic history of Late Quaternary contraction and expansion that characterizes highâlatitude species
Deciding Entailments in Inductive Separation Logic with Tree Automata
Separation Logic (SL) with inductive definitions is a natural formalism for
specifying complex recursive data structures, used in compositional
verification of programs manipulating such structures. The key ingredient of
any automated verification procedure based on SL is the decidability of the
entailment problem. In this work, we reduce the entailment problem for a
non-trivial subset of SL describing trees (and beyond) to the language
inclusion of tree automata (TA). Our reduction provides tight complexity bounds
for the problem and shows that entailment in our fragment is EXPTIME-complete.
For practical purposes, we leverage from recent advances in automata theory,
such as inclusion checking for non-deterministic TA avoiding explicit
determinization. We implemented our method and present promising preliminary
experimental results
Spatial Interpolants
We propose Splinter, a new technique for proving properties of
heap-manipulating programs that marries (1) a new separation logic-based
analysis for heap reasoning with (2) an interpolation-based technique for
refining heap-shape invariants with data invariants. Splinter is property
directed, precise, and produces counterexample traces when a property does not
hold. Using the novel notion of spatial interpolants modulo theories, Splinter
can infer complex invariants over general recursive predicates, e.g., of the
form all elements in a linked list are even or a binary tree is sorted.
Furthermore, we treat interpolation as a black box, which gives us the freedom
to encode data manipulation in any suitable theory for a given program (e.g.,
bit vectors, arrays, or linear arithmetic), so that our technique immediately
benefits from any future advances in SMT solving and interpolation.Comment: Short version published in ESOP 201
Predicting death and readmission after intensive care discharge
Background: Despite initial recovery from critical illness, many patients deteriorate after discharge from the intensive care unit (ICU). We examined prospectively collected data in an attempt to identify patients at risk of readmission or death after intensive care discharge. Methods: This was a secondary analysis of clinical audit data from patients discharged alive from a mixed medical and surgical (non-cardiac) ICU. Results: Four hundred and seventy-five patients (11.2%) died in hospital after discharge from the ICU. Increasing age, time in hospital before intensive care admission, Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and discharge Therapeutic Intervention Scoring System (TISS) score were independent risk factors for death after intensive care discharge. Three hundred and eighty-five patients (8.8%) were readmitted to intensive care during the same hospital admission. Increasing age, time in hospital before intensive care, APACHE II score, and discharge to a high dependency unit were independent risk factors for readmission. One hundred and forty-three patients (3.3%) were readmitted within 48 h of intensive care discharge. APACHE II scores and discharge to a high dependency or other ICU were independent risk factors for early readmission. The overall discriminant ability of our models was moderate with only marginal benefit over the APACHE II scores alone. Conclusions: We identified risk factors associated with death and readmission to intensive care. It was not possible to produce a definitive model based on these risk factors for predicting death or readmission in an individual patient.Not peer reviewedAuthor versio
Conformal-thin-sandwich initial data for a single boosted or spinning black hole puncture
Sequences of initial-data sets representing binary black holes in
quasi-circular orbits have been used to calculate what may be interpreted as
the innermost stable circular orbit. These sequences have been computed with
two approaches. One method is based on the traditional
conformal-transverse-traceless decomposition and locates quasi-circular orbits
from the turning points in an effective potential. The second method uses a
conformal-thin-sandwich decomposition and determines quasi-circular orbits by
requiring the existence of an approximate helical Killing vector. Although the
parameters defining the innermost stable circular orbit obtained from these two
methods differ significantly, both approaches yield approximately the same
initial data, as the separation of the binary system increases. To help
understanding this agreement between data sets, we consider the case of initial
data representing a single boosted or spinning black hole puncture of the
Bowen-York type and show that the conformal-transverse-traceless and
conformal-thin-sandwich methods yield identical data, both satisfying the
conditions for the existence of an approximate Killing vector.Comment: 13 pages, 2 figure
Molecular dynamic simulation of a homogeneous bcc -> hcp transition
We have performed molecular dynamic simulations of a Martensitic bcc->hcp
transformation in a homogeneous system. The system evolves into three
Martensitic variants, sharing a common nearest neighbor vector along a bcc
direction, plus an fcc region. Nucleation occurs locally, followed by
subsequent growth. We monitor the time-dependent scattering S(q,t) during the
transformation, and find anomalous, Brillouin zone-dependent scattering similar
to that observed experimentally in a number of systems above the transformation
temperature. This scattering is shown to be related to the elastic strain
associated with the transformation, and is not directly related to the phonon
response.Comment: 11 pages plus 8 figures (GIF format); to appear in Phys. Rev.
Parameterized complexity of DPLL search procedures
We study the performance of DPLL algorithms on parameterized problems. In particular, we investigate how difficult it is to decide whether small solutions exist for satisfiability and other combinatorial problems. For this purpose we develop a Prover-Delayer game which models the running time of DPLL procedures and we establish an information-theoretic method to obtain lower bounds to the running time of parameterized DPLL procedures. We illustrate this technique by showing lower bounds to the parameterized pigeonhole principle and to the ordering principle. As our main application we study the DPLL procedure for the problem of deciding whether a graph has a small clique. We show that proving the absence of a k-clique requires n steps for a non-trivial distribution of graphs close to the critical threshold. For the restricted case of tree-like Parameterized Resolution, this result answers a question asked in [11] of understanding the Resolution complexity of this family of formulas
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