Critical Frontier Research Articles

Dealing with difficult days: Functional coping dynamics in self-harm ideation and enactment

BackgroundSelf-harm affords people a means of coping. However, little is known about how functional coping dynamics differ between stressful situations in which people self-harm (enactment), think about harming (ideation), or experience no self-harmful thoughts or behaviours. MethodsParticipants (N = 1,157) aged 16−49 years (M = 18.21, SD = 3.24) with a recent history of self-harm (past 3 months) reported how they coped in response to their most significant recent stressor (3 months). ResultsAlmost 40% of participants, all of whom had self-harmed in the last 3 months, had no self-harm experience (thoughts or behaviours) in response to their most significant stressor in that time frame. In multivariate analysis, adjusting for symptoms of depression and anxiety, reappraisal coping was predictive of self-harm thoughts. Approach, emotion regulation and reappraisal coping were predictive of self-harm behaviour. Emotion regulation coping differentiated self-harm ideation and enactment groups. LimitationsThe cross-sectional design of the study precludes the ability to make inferences regarding causality. Further, there is no agreed definition of ‘recent’ self-harm. ConclusionsTaken together, the findings suggest that functional coping dynamics may be differentially associated with self-harm ideation and enactment. This is important, given that understanding the transitions between ideation and enactment has been identified as a critical frontier in suicide prevention. Further, results indicate that seemingly innocuous events may have a profound impact as tipping points for enaction; this has implications for clinical practice, including the co-production of safety plans.

Implementation Science: Why It Matters for the Future of Social Work

ABSTRACTBridging the gap between research and practice is a critical frontier for the future of social work. Integrating implementation science into social work can advance our profession’s effort to bring research and practice closer together. Implementation science examines the factors, processes, and strategies that influence the uptake, use, and sustainability of empirically supported interventions, practice innovations, and social policies in routine practice settings. The aims of this article are to describe the key characteristics of implementation science, illustrate how implementation science matters to social work by describing several contributions this field can make to reducing racial and ethnic disparities in mental health care, and outline a training agenda to help integrate implementation science in graduate-level social work programs.

Protected area types, strategies and impacts in Brazil's Amazon: public protected area strategies do not yield a consistent ranking of protected area types by impact.

The leading policy to conserve forest is protected areas (PAs). Yet, PAs are not a single tool: land users and uses vary by PA type; and public PA strategies vary in the extent of each type and in the determinants of impact for each type, i.e. siting and internal deforestation. Further, across regions and time, strategies respond to pressures (deforestation and political). We estimate deforestation impacts of PA types for a critical frontier, the Brazilian Amazon. We separate regions and time periods that differ in their deforestation and political pressures and document considerable variation in PA strategies across regions, time periods and types. The siting of PAs varies across regions. For example, all else being equal, PAs in the arc of deforestation are relatively far from non-forest, while in other states they are relatively near. Internal deforestation varies across time periods, e.g. it is more similar across the PA types for PAs after 2000. By contrast, after 2000, PA extent is less similar across PA types with little non-indigenous area created inside the arc. PA strategies generate a range of impacts for PA types--always far higher within the arc--but not a consistent ranking of PA types by impact.

Enclosing resources on the islands of Kinmen and Xiamen: From war blockade to financializing natural heritage

The cultures of the islands of Kinmen and Xiamen, also respectively Quemoy and Amoy, are tightly interwoven with the South China coastal region of Fujian. Both archipelagos played important historical roles in coastal defense and have been home to many Overseas Chinese since the 19th Century. A decisive battle in the Chinese Civil War was fought on Kinmen in 1949, cutting off Kinmen’s connection with Xiamen and Fujian. Positioned on a critical frontier between the ‘free world’ and the ‘communist world’, self-sufficiency became militarily important in the event of a blockade. After 1979, Xiamen was designated as a special economic zone attracting large flows of foreign investment and experiencing rapid urban development. Since 2002 the scheduled ferries between Kinmen and Xiamen reopened connections between Kinmen and its neighbor cities in the People’s Republic of China. Renewed exchange highlighted the remarkable differences between the two archipelagos’ developmental paths that had developed over the course of the 53-year suspension of contact. This paper analyzes these divergent developmental paths through comparative case studies involving forms of enclosure. The wetland conservation at Tzi Lake in Kinmen as well as gentrified residential developments around Yuan-dan Lake in Xiamen are compared; changing relationships, the impact of the sudden re-opening of borders, new forms of enclosure under globalization; and regional flows of capitals are discussed.

Scrutinizing the epigenetics revolution.

Epigenetics is one of the most rapidly expanding fields in the life sciences. Its rise is frequently framed as a revolutionary turn that heralds a new epoch both for gene-based epistemology and for the wider discourse on life that pervades knowledge-intensive societies of the molecular age. The fundamentals of this revolution remain however to be scrutinized, and indeed the very contours of what counts as ‘epigenetic' are often blurred. This is reflected also in the mounting discourse on the societal implications of epigenetics, in which vast expectations coexist with significant uncertainty about what aspects of this science are most relevant for politics or policy alike. This is therefore a suitable time to reflect on the directions that social theory could most productively take in the scrutiny of this revolution. Here we take this opportunity in both its scholarly and normative dimension, that is, proposing a roadmap for social theorizing on epigenetics that does not shy away from, and indeed hopefully guides, the framing of its most socially relevant outputs. To this end, we start with an epistemological reappraisal of epigenetic discourse that valorizes the blurring of meanings as a critical asset for the field and privileged analytical entry point. We then propose three paths of investigation. The first looks at the structuring elements of controversies and visions around epigenetics. The second probes the mutual constitution between the epigenetic reordering of living phenomena and the normative settlements that orient individual and collective responsibilities. The third highlights the material import of epigenetics and the molecularization of culture that it mediates. We suggest that these complementary strands provide both an epistemically and socially self-reflective framework to advance the study of epigenetics as a molecular juncture between nature and nurture and thus as the new critical frontier in the social studies of the life sciences.

Monte Carlo Study of a Spin-3/2 Blume-Emery-Griffiths Model on a Honeycomb Lattice

We study the phase diagram of the spin-3/2 Blume-Emery-Griffiths model on a honeycomb lattice by Monte Carlo simulations in order to verify the presence of some peculiar features predicted by the effective field theory (EFT) with correlations. The locations of the order-disorder phase boundaries are estimated from thermal variations of the magnetic susceptibility curves. It is found that for positive values of the biquadratic interactions the critical boundary shows a discontinuous character as a function of the single-ion anisotropy strength, in line with the EFT expectations. However, for negative values of the biquadratic interactions the step-like variation of the critical frontier predicted by EFT was not reproduced.

Differentiating Suicide Attempters from Suicide Ideators: A Critical Frontier for Suicidology Research

Most individuals who consider suicide do not make suicide attempts. It is therefore critical to identify which suicide ideators are at greatest risk of acting on their thoughts. However, few seminal theories of suicide address which ideators go on to make attempts. In addition, perhaps surprisingly, most oft-cited risk factors for suicide-such as psychiatric disorders, depression, hopelessness, and even impulsivity-distinguish poorly between those who attempt suicide and those who only consider suicide. This special section of Suicide and Life-Threatening Behavior serves to highlight this knowledge gap and provide new data on differences (and similarities) between suicide attempters and suicide ideators.

Consensus on context-specific strategies for reducing the stigma of human immunodeficiency virus/acquired immunodeficiency syndrome in Zambézia Province, Mozambique

Stigma has been implicated in poor outcomes of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) care. Reducing stigma is important for HIV prevention and long-term treatment success. Although stigma reduction interventions are conducted in Mozambique, little is known about the current nature of stigma and the efficacy and effectiveness of stigma reduction initiatives. We describe action research to generate consensus on critical characteristics of HIV stigma and anti-stigma interventions in Zambézia Province, Mozambique. Qualitative data gathering methods, including in-depth key-informant interviews, community interviews and consensus group sessions, were utilized. Delphi methods and the strategic options development analysis technique were used to synthesize qualitative data. Key findings are that stigma enacted by the general public might be declining in tandem with the HIV/AIDS epidemic in Mozambique, but there is likely excessive residual fear of HIV disease and community attitudes that sustain high levels of perceived stigma. HIV-positive women accessing maternal and child health services appear to shoulder a disproportionate burden of stigma. Unintentional biases among healthcare providers are currently the critical frontier of stigmatization, but there are few interventions designed to address them. Culturally sensitive psychotherapies are needed to address psychological distress associated with internalized stigma and these interventions should complement current supports for voluntary counseling and testing. While advantageous for defining stakeholder priorities for stigma reduction efforts, confirmatory quantitative studies of these consensus positions are needed before the launch of specific interventions.

Phase boundaries of a spin-3/2 Blume–Emery–Griffiths model on a honeycomb lattice

The spin-3/2 Blume–Emery–Griffiths model on a honeycomb lattice is studied by Monte Carlo simulations with the goal to determine phase diagrams for a range of the model parameters and to investigate the nature of the phase transitions between the respective phases. For positive values of the biquadratic to bilinear interaction ratio α, we find two ferromagnetically ordered phases, F1 and F2, with the sublattice magnetizations (1/2,1/2) and (3/2,3/2), respectively, and our results confirm the discontinuous character of the order-disorder critical line as a function of the single-ion anisotropy strength, predicted by the effective-field theory (EFT). For negative values of α, there is another ferrimagnetic phase of the type (1/2,3/2), located between F1 and F2. However, the step-like variation of the order-disorder critical frontier obtained from EFT for large negative α is not reproduced and thus deemed artifact of the EFT approximation. Finite-size scaling analysis performed at various points between the respective identified phases gave the ratio of critical exponents γ/ν consistent with the 2D Ising universality class, except in the vicinity of the boundary intersection, where the results deviated from the standard values beyond the measurement errors.

Potts critical frontiers of inhomogeneous and asymmetric bow-tie lattices

We study the critical frontiers of the Potts model on two-dimensional bow-tie lattices with fully inhomogeneous coupling constants. Generally, for the Potts critical frontier to be found exactly, the underlying lattice must be a three-uniform hypergraph. A more general class of lattices are the four-uniform ones, with unit cells contained within four boundary vertices. We demonstrate that in some cases, such lattices can be decomposed into triangular cells, and solved using a modification of standard techniques. This leads to the exact inhomogeneous Potts critical frontiers on various lattices, such as the bow-tie lattice with five different couplings, and critical points for asymmetric bow-tie lattices.

Potts and percolation models on bowtie lattices

We give the exact critical frontier of the Potts model on bowtie lattices. For the case of q = 1, the critical frontier yields the thresholds of bond percolation on these lattices, which are exactly consistent with the results given by Ziff et al. [J. Phys. A 39, 15083 (2006)]. For the q = 2 Potts model on a bowtie A lattice, the critical point is in agreement with that of the Ising model on this lattice, which has been exactly solved. Furthermore, we do extensive Monte Carlo simulations of the Potts model on a bowtie A lattice with noninteger q. Our numerical results, which are accurate up to seven significant digits, are consistent with the theoretical predictions. We also simulate the site percolation on a bowtie A lattice, and the threshold is s(c) = 0.5479148(7). In the simulations of bond percolation and site percolation, we find that the shape-dependent properties of the percolation model on a bowtie A lattice are somewhat different from those of an isotropic lattice, which may be caused by the anisotropy of the lattice.

Critical manifold of the Potts model: Exact results and homogeneity approximation

The q-state Potts model has stood at the frontier of research in statistical mechanics for many years. In the absence of a closed-form solution, much of the past effort has focused on locating its critical manifold, trajectory in the parameter (q,e(J)) space where J is the reduced interaction, along which the free energy is singular. However, except in isolated cases, antiferromagnetic (AF) models with J<0 have been largely neglected. In this paper we consider the Potts model with AF interactions focusing on obtaining its critical manifold in exact and/or closed-form expressions. We first reexamine the known critical frontiers in light of AF interactions. For the square lattice we confirm the Potts self-dual point to be the sole critical frontier for J>0. We also locate its critical frontier for J<0 and find it to coincide with a solvability condition observed by Baxter in 1982 [R. J. Baxter, Proc. R. Soc. London Ser. A 388, 43 (1982)]. For the honeycomb lattice we show that the known critical frontier holds for all J, and determine its critical q(c) = 1/2(3 + sqrt[5]) = 2.61803 beyond which there is no transition. For the triangular lattice we confirm the known critical frontier to hold only for J>0. More generally we consider the centered-triangle (CT) and Union-Jack (UJ) lattices consisting of mixed J and K interactions, and deduce critical manifolds under homogeneity hypotheses. For K = 0 the CT lattice is the diced lattice, and we determine its critical manifold for all J and find q(c) = 3.32472. For K = 0 the UJ lattice is the square lattice and from this we deduce both the J > 0 and J < 0 critical manifolds and q(c) = 3. Our theoretical predictions are compared with recent numerical results.

Relationship between pace of life and immune responses in wild rodents

Life histories of animals tend to vary along a slow to fast continuum. Those with fast life histories have shorter life spans, faster development, and higher reproductive rates relative to animals with slower life histories. These differences in life histories have been linked to differences in investment in immunological defenses. Animals with faster life histories are predicted to invest relatively more in innate immune responses, which include rapidly‐deployed, non‐specific defenses against a broad spectrum of invaders. On the other hand, animals with slower life histories are predicted to invest relatively more in adaptive immune responses, which are more slowly‐deployed and are highly pathogen‐specific. These predictions have been confirmed in some taxa, but other studies have not found this association. We tested this prediction by measuring innate and adaptive immunity of white‐footed mice Peromyscus leucopus, chipmunks Tamias striatus, and gray squirrels Sciurus carolinensis, three species of rodents that inhabit deciduous forests in the northeastern US. These species exhibit a range of life histories, with mice having a relatively fast life history, squirrels a relatively slow one, and chipmunks an intermediate one. We found mice to have the greatest ‘bacterial killing capacity’, a common measure of innate immunity, and squirrels the lowest, consistent with the pace‐of‐life immune‐defense hypothesis. We also found squirrels to mount the most pronounced antibody response when challenged with lipopolysaccharide (LPS), an immunogenic component of bacteria, while mice had the lowest, again consistent with predictions based on their life histories. These results have implications beyond ecoimmunology because the probability that a host species will transmit an infection – its ‘reservoir competence’ – has been linked to its immune strategy. Understanding the relationship between immunology and reservoir competence is a critical frontier in the ecology of infectious diseases.

The Sherrington–Kirkpatrick model in the presence of a bimodal random field: a one-stepreplica-symmetry-breaking approach

The infinite-range-interaction Ising spin glass in the presence of a bimodal random field isinvestigated through the replica method. A one-step replica-symmetry-breakingprocedure is considered, and its results are compared to previous ones, obtained in thereplica-symmetry approximation. An analysis of the thermodynamic properties at lowtemperatures shows that the one-step replica-symmetry-breaking produces a substantialamelioration with respect to the replica-symmetric solution; in particular, thelow-temperature negative-entropy problem is practically resolved within this improvedapproach. A curious aspect in replica-symmetric phase diagrams concerns the border of theferromagnetic phase, which for sufficiently high values of the field may present one or eventwo tricritical points. In this latter case, it is shown that the higher-temperature tricriticalpoint remains; however, the low-temperature one disappears within the one-stepreplica-symmetry-breaking procedure, yielding a first-order critical frontier down to zerotemperature.

Farm Wide Dynamics: The Next Critical Wind Energy Frontier

The dynamic behaviour of wind turbines continues to be a major area of research in the wind power industry. Increasingly, wind turbines are grouped into large arrays that form farms capable of generating hundreds of megawatts of power. Farm wide dynamics refers to the collective behaviour of multiple wind turbines that cumulatively produces effects that cannot simply be modelled by summing the behaviours of individual machines. Many facets within this topic have been addressed singly in the literature and are widely used in industry; while others are less understood. It is here asserted that the farm wide dynamic approach is essential for the optimum design, power production, management, and profitability of a wind farm. The inter-relationships between the subcomponents of farm siting, power production, and maintenance are illustrated and discussed. A simple weighting system to assist in the prioritization of the critical dynamic elements is proposed.

Trends in biomedical engineering: focus on Regenerative Medicine

Regenerative medicine is a critical frontier in biomedical and clinical research. The major progresses in the last few years were driven by a strong clinical need which could benefit from regenerative medicine outcomes for the treatment of a large number of conditions including birth defects, degenerative and neoplastic diseases, and traumatic injuries. Regenerative medicine applies the principles of engineering and life sciences to enhance the comprehension of the fundamental biological mechanisms underlying the structure-function relationships in physiologic and pathologic tissues and to accomplish alternative strategies for developing in vitro biological substitutes which are able to restore, maintain, or improve tissue, and organ function. This paper reviews selected approaches currently being investigated at Politecnico di Milano in the field of regenerative medicine. Specific tissue-oriented topics are divided in three sections according to each developmental stage: in vitro study, pre-clinical study, and clinical application. In vitro studies investigate the basic phenomena related to gene delivery, stem cell behavior, tissue regeneration, and to explore dynamic culture potentiality in different applications: cardiac and skeletal muscle, cartilage, hematopoietic system, peripheral nerve, and gene delivery. Specific fields of regenerative medicine, i.e., bone, blood vessels, and ligaments engineering have already reached the preclinical stage providing promising insights for further research towards clinical applications. The translation of the results obtained during in vitro and preclinical steps into clinical organ replacement is a very challenging issue, which can offer a valid alternative to fight morbidity, organ shortage, and ethical-social problems associated with allotransplantation as shown in the clinical case reported in this review.

Publisher's Note: Critical frontier of the Potts and percolation models on triangular-type and kagome-type lattices. II. Numerical analysis [Phys. Rev. E81, 061111 (2010)

Publisher's Note: Critical frontier of the Potts and percolation models on triangular-type and kagome-type lattices. II. Numerical analysis [Phys. Rev. E<b>81</b>, 061111 (2010)

Critical frontier of the Potts and percolation models on triangular-type and kagome-type lattices. I. Closed-form expressions

We consider the Potts model and the related bond, site, and mixed site-bond percolation problems on triangular-type and kagome-type lattices, and derive closed-form expressions for the critical frontier. For triangular-type lattices the critical frontier is known, usually derived from a duality consideration in conjunction with the assumption of a unique transition. Our analysis, however, is rigorous and based on an established result without the need of a uniqueness assumption, thus firmly establishing all derived results. For kagome-type lattices the exact critical frontier is not known. We derive a closed-form expression for the Potts critical frontier by making use of a homogeneity assumption. The closed-form expression is unique, and we apply it to a host of problems including site, bond, and mixed site-bond percolations on various lattices. It yields exact thresholds for site percolation on kagome, martini, and other lattices and is highly accurate numerically in other applications when compared to numerical determination.

Critical frontier of the Potts and percolation models on triangular-type and kagome-type lattices. II. Numerical analysis

In the preceding paper, one of us (F. Y. Wu) considered the Potts model and bond and site percolation on two general classes of two-dimensional lattices, the triangular-type and kagome-type lattices, and obtained closed-form expressions for the critical frontier with applications to various lattice models. For the triangular-type lattices Wu's result is exact, and for the kagome-type lattices Wu's expression is under a homogeneity assumption. The purpose of the present paper is twofold: First, an essential step in Wu's analysis is the derivation of lattice-dependent constants A,B,C for various lattice models, a process which can be tedious. We present here a derivation of these constants for subnet networks using a computer algorithm. Second, by means of a finite-size scaling analysis based on numerical transfer matrix calculations, we deduce critical properties and critical thresholds of various models and assess the accuracy of the homogeneity assumption. Specifically, we analyze the q -state Potts model and the bond percolation on the 3-12 and kagome-type subnet lattices (n×n):(n×n) , n≤4 , for which the exact solution is not known. Our numerical determination of critical properties such as conformal anomaly and magnetic correlation length verifies that the universality principle holds. To calibrate the accuracy of the finite-size procedure, we apply the same numerical analysis to models for which the exact critical frontiers are known. The comparison of numerical and exact results shows that our numerical values are correct within errors of our finite-size analysis, which correspond to 7 or 8 significant digits. This in turn infers that the homogeneity assumption determines critical frontiers with an accuracy of 5 decimal places or higher. Finally, we also obtained the exact percolation thresholds for site percolation on kagome-type subnet lattices (1×1):(n×n) for 1≤n≤6 .

T1922 The Eqqq-Rich C-Terminus of Human Apolipoprotein a-IV Inhibits Basolateral Chylomicron Triacylglycerol Secretion

Background: The colonic microbiome is remarkable in that it is amongst the most densely populated microbial habitats on Earth. The study of gut microbial ecology and its interplay with the host metabolome has emerged as a critical frontier in contemporary nutritional and metabolic research. Classic studies in physiology have shown that the gut microbiome plays an important role in nitrogen balance of the host. Urea, produced by the host, is hydrolyzed in the colon by urease-producing gut bacteria and the resultant ammonia is absorbed by the host and utilized for protein metabolism. In this study, we determined the effect of the gut microbiome on the metabolic alterations induced by a low protein diet (LPD). Methods and Results: Female C57B/6J mice were fed either a normal chow (20% kcal protein) or low protein diet (3% kcal protein) for 1 month. Metabolic phenotyping revealed that mice fed a low protein diet failed to gain weight despite a 40% increase in food intake. Compared to mice fed a normal chow diet, mice fed a LPD also showed significant alterations in body composition, as assessed by MRI, with a decrease in lean mass and a proportional increase in fat mass as well as a significant increase in energy expenditure, as determined by indirect calorimetry. In addition, LPD fed mice suffered a profound defect of water conservation manifested as severe polydypsia and polyuria. Remarkably, except for growth retardation, the administration of oral antibiotics to mice fed a LPD dramatically prevented all of these adverse metabolic sequelae. GC-MS of urinary samples revealed that oral antibiotics did not lead to profound alterations in urinary amino acid excretion suggesting that gut bacteria were not competing with the host for dietary nitrogen sources in a significant way. This notion is supported by the failure of LPD mice to increase serum IGF-1 levels and normalize body weight when placed on oral antibiotics. Preliminary determination of gut microbiome composition, by 16S rDNA sequencing using the 454/Roche method and taxonomic group assignment at the genus level using RDPclassifier, revealed modest alterations induced by a LPD. Conclusions: These results suggest that the gut microbiome evokes deleterious metabolic consequences in the host in the setting of a low protein diet that are independent of competition for dietary nitrogen. The gut microbiome may, therefore, play an important role in the regulation of host metabolic physiology in settings where the consumption of dietary protein is severely limited.