We consider the problem of constructing optimal decision trees: given a collection of tests that can disambiguate between a set of
m
possible diseases, each test having a cost, and the a priori ...likelihood of any particular disease, what is a good adaptive strategy to perform these tests to minimize the expected cost to identify the disease? This problem has been studied in several works, with
O
(log
m
)-approximations known in the special cases when either costs or probabilities are uniform. In this paper, we settle the approximability of the general problem by giving a tight
O
(log
m
)-approximation algorithm.
We also consider a substantial generalization, the adaptive traveling salesman problem. Given an underlying metric space, a random subset
S
of vertices is drawn from a known distribution, but
S
is initially unknown—we get information about whether any vertex is in
S
only when it is visited. What is a good adaptive strategy to visit all vertices in the random subset
S
while minimizing the expected distance traveled? This problem has applications in routing message ferries in ad hoc networks and also models switching costs between tests in the optimal decision tree problem. We give a polylogarithmic approximation algorithm for adaptive TSP, which is nearly best possible due to a connection to the well-known group Steiner tree problem. Finally, we consider the related adaptive traveling repairman problem, where the goal is to compute an adaptive tour minimizing the expected sum of arrival times of vertices in the random subset
S
; we obtain a polylogarithmic approximation algorithm for this problem as well.
Functional neuroimaging studies in obesity have identified alterations in the connectivity within the reward network leading to decreased homeostatic control of ingestive behavior. However, the ...neural mechanisms underlying sex differences in the prevalence of food addiction in obesity is unknown. The aim of the study was to identify functional connectivity alterations associated with: (1) Food addiction, (2) Sex- differences in food addiction, (3) Ingestive behaviors. 150 participants (females: N = 103, males: N = 47; food addiction: N = 40, no food addiction: N = 110) with high BMI ≥ 25 kg/m
underwent functional resting state MRIs. Participants were administered the Yale Food Addiction Scale (YFAS), to determine diagnostic criteria for food addiction (YFAS Symptom Count ≥ 3 with clinically significant impairment or distress), and completed ingestive behavior questionnaires. Connectivity differences were analyzed using a general linear model in the CONN Toolbox and images were segmented using the Schaefer 400, Harvard-Oxford Subcortical, and Ascending Arousal Network atlases. Significant connectivities and clinical variables were correlated. Statistical significance was corrected for multiple comparisons at q < .05. (1) Individuals with food addiction had greater connectivity between brainstem regions and the orbital frontal gyrus compared to individuals with no food addiction. (2) Females with food addiction had greater connectivity in the salience and emotional regulation networks and lowered connectivity between the default mode network and central executive network compared to males with food addiction. (3) Increased connectivity between regions of the reward network was positively associated with scores on the General Food Cravings Questionnaire-Trait, indicative of greater food cravings in individuals with food addiction. Individuals with food addiction showed greater connectivity between regions of the reward network suggesting dysregulation of the dopaminergic pathway. Additionally, greater connectivity in the locus coeruleus could indicate that the maladaptive food behaviors displayed by individuals with food addiction serve as a coping mechanism in response to pathological anxiety and stress. Sex differences in functional connectivity suggest that females with food addiction engage more in emotional overeating and less cognitive control and homeostatic processing compared to males. These mechanistic pathways may have clinical implications for understanding the sex-dependent variability in response to diet interventions.
Neuroticism is one of the most robust risk factors for addictive behaviors including food addiction (a key contributor to obesity), although the associated mechanisms are not well understood. A ...transdiagnostic approach was used to identify the neuroticism-related neuropsychological and gut metabolomic patterns associated with food addiction. Predictive modeling of neuroticism was implemented using multimodal features (23 clinical, 13,531 resting-state functional connectivity (rsFC), 336 gut metabolites) in 114 high body mass index (BMI ≥25 kg/m2) (cross-sectional) participants. Gradient boosting machine and logistic regression models were used to evaluate classification performance for food addiction. Neuroticism was significantly associated with food addiction (P < 0.001). Neuroticism-related features predicted food addiction with high performance (89% accuracy). Multimodal models performed better than single-modal models in predicting food addiction. Transdiagnostic alterations corresponded to rsFC involved in the emotion regulation, reward, and cognitive control and self-monitoring networks, and the metabolite 3-(4-hydroxyphenyl) propionate, as well as anxiety symptoms. Neuroticism moderated the relationship between BMI and food addiction. Neuroticism drives neuropsychological and gut microbial signatures implicated in dopamine synthesis and inflammation, anxiety, and food addiction. Such transdiagnostic models are essential in identifying mechanisms underlying food addiction in obesity, as it can help develop multiprong interventions to improve symptoms.
•Neuroticism is associated with a unique brain-gut-microbiome-clinical signature.•Emotion regulation, reward, and cognitive control brain networks were involved.•A metabolite implicated in dopamine synthesis, inflammation, and anxiety emerged.•This structure predicted food addiction diagnoses in individuals with high BMI.•Neuroticism moderated the relationship between body mass index and food addiction.
We use the Sloan Digital Sky Survey II Supernova Survey (SDSS-II SNS) data to measure the volumetric core collapse supernova (CCSN) rate in the redshift range (0.03 < z < 0.09). Using a sample of 89 ...CCSN, we find a volume-averaged rate of 1.06+ or -0.19 x 10 super(-4)((h/0.7) super(3)/(yr Mpc super(3))) at a mean redshift of 0.072+ or -0.009. We measure the CCSN luminosity function from the data and consider the implications on the star formation history.
Obesity contributes to physical comorbidities and mental health consequences. We explored whether physical activity could influence more than metabolic regulation and result in psychological benefits ...through the brain-gut microbiome (BGM) system in a population with high BMI. Fecal samples were obtained for 16 s rRNA profiling and fecal metabolomics, along with psychological and physical activity questionnaires. Whole brain resting-state functional MRI was acquired, and brain connectivity metrics were calculated. Higher physical activity was significantly associated with increased connectivity in inhibitory appetite control brain regions, while lower physical activity was associated with increased emotional regulation network connections. Higher physical activity was also associated with microbiome and metabolite signatures protective towards mental health and metabolic derangements. The greater resilience and coping, and lower levels of food addiction seen with higher physical activity, may be explained by BGM system differences. These novel findings provide an emphasis on the psychological and resilience benefits of physical activity, beyond metabolic regulation and these influences seem to be related to BGM interactions.
We study the stellar populations of Type Ia supernova (SN Ia) host galaxies using Sloan Digital Sky Survey (SDSS)-II spectroscopy. The main focus is on the relationships of SN Ia properties with ...stellar velocity dispersion and the stellar population parameters age, metallicity and element abundance ratios. We concentrate on a sub-sample of 84 SNe Ia from the SDSS-II Supernova Survey and find that SALT2 stretch factor values show the strongest dependence on stellar population age. Hence, more luminous SNe Ia appear in younger stellar progenitor systems. No statistically significant trends in the Hubble residual with any of the stellar population parameters studied are found. Moreover, the method of photometric stellar mass derivation affects the Hubble residual-mass relationship. For an extended sample (247 objects), including SNe Ia with SDSS host galaxy photometry only, the Hubble residual-mass relationship behaves as a sloped step function. In the high-mass regime, probed by our host spectroscopy sample, this relationship is flat. Below a stellar mass of ∼2 × 1010 M, i.e. close to the evolutionary transition mass of low-redshift galaxies, the trend changes dramatically such that lower mass galaxies possess lower luminosity SNe Ia after light-curve corrections. The sloped step function of the Hubble residual-mass relationship should be accounted for when using stellar mass as a further parameter for minimizing the Hubble residuals.
Chronic pain is a major public health problem in the United States costing $635 billion annually. Hospitalizations for chronic pain in childhood have increased almost tenfold in the past decade, ...without breakthroughs in novel treatment strategies. Findings from brain imaging studies using structural and resting-state fMRI could potentially help personalize treatment to address this costly and prevalent health problem by identifying the underlying brain pathways that contribute, facilitate, and maintain chronic pain. The aim of this review is to synthesize structural and resting-state network pathology identified by recent brain imaging studies in pediatric chronic pain populations and discuss the potential impact of chronic pain on cortical development. Sex differences as well as treatment effects on these cortical alterations associated with symptom changes are also summarized. This area of research is still in its infancy with currently limited evidence available from a small number of studies, some of which suffer from limitations such as small sample size and suboptimal methodology. The identification of brain signatures of chronic pain in children may help to develop new pathways for future research as well as treatment strategies.
Pain is a highly complex and individualized experience with biopsychosocial components. Neuroimaging research has shown evidence of the involvement of the central nervous system in the development ...and maintenance of chronic pain conditions, including urological chronic pelvic pain syndrome (UCPPS). Furthermore, a history of early adverse life events (EALs) has been shown to adversely impact symptoms throughout childhood and into adulthood. However, to date, the role of EAL's in the central processes of chronic pain have not been adequately investigated. We studied 85 patients (56 females) with UCPPS along with 86 healthy controls (HCs) who had resting-state magnetic resonance imaging scans (59 females), and data on EALs as a part of the Multidisciplinary Approach to the Study of Chronic Pelvic Pain (MAPP) Research Network Study. We used graph theory methods in order to investigate the impact of EALs on measures of centrality, which characterize information flow, communication, influence, and integration in a priori selected regions of interest. Patients with UCPPS exhibited lower centrality in the right anterior insula compared to HCs, a key node in the salience network. Males with UCPPS exhibited lower centrality in the right anterior insula compared the HC males. Females with UCPPS exhibited greater centrality in the right caudate nucleus and left angular gyrus compared to HC females. Males with UCPPS exhibited lower centrality in the left posterior cingulate, angular gyrus, middle temporal gyrus, and superior temporal sulcus, but greater centrality in the precuneus and anterior mid-cingulate cortex (aMCC) compared to females with UCPPS. Higher reports of EALs was associated with greater centrality in the left precuneus and left aMCC in females with UCPPS. This study provides evidence for disease and sex-related alterations in the default mode, salience, and basal ganglia networks in patients with UCPPS, which are moderated by EALs, and associated with clinical symptoms and quality of life (QoL).
Chronic pain affects nearly 20% of the U.S. population. It is a leading cause of disability globally and is associated with a heightened risk for suicide. The role of the central nervous system in ...the perception and maintenance of chronic pain has recently been accepted, but specific brain circuitries involved have yet to be mapped across pain types in a large-scale study.
We used data from the UK Biobank (N = 21,968) to investigate brain structural alterations in individuals reporting chronic pain compared with pain-free control participants and their mediating effect on history of suicide attempt.
Chronic pain and, more notably, chronic multisite pain was associated with, on average, lower surface area throughout the cortex after adjusting for demographic, clinical, and neuropsychiatric confounds. Only participants with abdominal pain showed lower subcortical volumes, including the amygdala and brainstem, and lower cerebellum volumes. Participants with chronic headaches showed a widespread thicker cortex compared with control participants. Mediation analyses revealed that precuneus thickness mediated the relationship of chronic multisite pain and history of suicide attempt. Mediating effects were also identified specific to localized pain, with the strongest effect being amygdala volume in individuals with chronic abdominal pain.
Results support a widespread effect of chronic pain on brain structure and distinct brain structures underlying chronic musculoskeletal pain, visceral pain, and headaches. Mediation effects of regions in the extended ventromedial prefrontal cortex subsystem suggest that exacerbated negative internal states, negative self-referencing, and impairments in future planning may underlie suicidal behaviors in individuals with chronic pain.
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