Non-Decreasing Sequences

Non-decreasing sequences are a generalization of binary covering arrays, which has made research on non-decreasing sequences important in both math and computer science. A non-decreasing sequence of subsets of a finite set S of size s, {S1, S2,.... St}, length t, and strength d, is a sequence of non-empty subsets where the union of any d previous subsets in the sequence does not contain any subsequent subset. The goal of this research is to find properties of these non-decreasing sequences as the variables d, s, and t change. We also explored methods for creating a maximum length for a non-decreasing sequence given d and s. Through our research, we discovered and proved basic properties of these non-decreasing sequences. In addition to this, we can describe a method we used while trying to find the maximum length of a sequence. In the future, research can be conducted to find an exact formula that will generate a maximum length sequence given a non-decreasing sequence of strength d

Examining the Legacy of Transgenerational Trauma and its Effects on Contemporary African American Adults in Parenting and Caregiver Roles to African American Adolescents

The system of institutional enslavement in North America has produced myriad effects on the contemporary African American community via the transmission of individual, familial, and collective trauma across generations (Carter, 2015; DeGruy, 2005; Weingarten, 2004). This research explored the roles of parent and caregiver within this cultural group in an effort to determine how past traumas have influenced the lived experiences and world view of African Americans in these roles. While research on certain historically marginalized cultural and religious groups is plentiful, there is a clear lacuna of scholarly investigation into the African American experience, particularly as it relates to the roles of parent and caregiver. Parenting is among the most significant of human endeavors. The impact of parenting and care-giving on future generations is immeasurable; it is the apex of humanity. A great majority of the world’s cultures and religions place unequaled value on parenting as well as acting in the place of parents, as in the case of caregivers. These roles are even considered sacred within many groups. For these reasons, this aspect of the African American lived experience was examined in this research. The inquiry examined and presented various theories in order to offer a comprehensive background related to this topic. Transgenerational trauma theory provided the foundation for this research, along with cultural trauma and historical trauma theories. Supplemental investigations of self-determination theory, critical race theory, racial/ethnic identity development theory/nigrescence, race-based trauma theory, post traumatic slave syndrome, and acculturative stress theory also were incorporated in an effort to provide a comprehensive perspective. After analyzing the emergent themes resulting from the data collection process, findings suggested that several factors contributed to African American parenting styles, traditions, and perceptions. Among the most ubiquitous were fear, control, punishment, and separation. Fear has been used to take and maintain control over certain populations within American culture. Often, these more prevalent themes implicated the American criminal justice system as a key factor of oppression. Not only has it had the power to mete out punishment, but also to disenfranchise people, affect economic status, and instigate separation within families and from society. Historically, these same tactics have been used against African Americans and have maintained the cycle of transgenerational trauma symptoms to the extent that they have become embedded in the culture via the parenting relationship. These exploratory research findings have suggested multiple factors that affect how parenting and care-giving are viewed in the contemporary African American community. This inquiry aimed to encapsulate how past collective traumas have been integrated into the lived experiences of African Americans and to illuminate the effects of the transferred trauma. The current research indicated that trauma effects have been transmitted via familial and cultural means, which have become manifest in the parent and caregiver relationships in various forms that can be better understood within a transgenerational context. Notably, risk and protective factors were identified as well as commonly incorporated coping mechanisms within the African American community regarding parenting philosophies and behaviors

Predation pressure shapes brain anatomy in the wild

The predation pressure data were collected by AEM and AED as part of an ERC-funded project (BioTIME 250189), AEM was supported by the Royal Society, AK and NK were supported by the Knut and Alice Wallenberg Foundation (KAW2013.0072 to NK).There is remarkable diversity in brain anatomy among vertebrates and evidence is accumulating that predatory interactions are crucially important for this diversity. To test this hypothesis, we collected female guppies (Poecilia reticulata) from 16 wild populations and related their brain anatomy to several aspects of predation pressure in this ecosystem, such as the biomass of the four major predators of guppies (one prawn and three fish species), and predator diversity (number of predatory fish species in each site). We found that populations from localities with higher prawn biomass had relatively larger telencephalon size as well as larger brains. Optic tectum size was positively associated with one of the fish predator’s biomass and with overall predator diversity. However, both olfactory bulb and hypothalamus size were negatively associated with the biomass of another of the fish predators. Hence, while fish predator occurrence is associated with variation in brain anatomy, prawn occurrence is associated with variation in brain size. Our results suggest that cognitive challenges posed by local differences in predator communities may lead to changes in prey brain anatomy in the wild.Publisher PDFPeer reviewe

Variable Hard X-ray Emission from the Candidate Accreting Black Hole in Dwarf Galaxy Henize 2-10

We present an analysis of the X-ray spectrum and long-term variability of the nearby dwarf starburst galaxy Henize 2-10. Recent observations suggest that this galaxy hosts an actively accreting black hole with mass ~10^6 M_sun. The presence of an AGN in a low-mass starburst galaxy marks a new environment for active galactic nuclei (AGNs), with implications for the processes by which "seed" black holes may form in the early Universe. In this paper, we analyze four epochs of X-ray observations of Henize 2-10, to characterize the long-term behavior of its hard nuclear emission. We analyze observations with Chandra from 2001 and XMM-Newton from 2004 and 2011, as well as an earlier, less sensitive observation with ASCA from 1997. Based on detailed analysis of the source and background, we find that the hard (2-10 keV) flux of the putative AGN has decreased by approximately an order of magnitude between the 2001 Chandra observation and exposures with XMM-Newton in 2004 and 2011. The observed variability confirms that the emission is due to a single source. It is unlikely that the variable flux is due to a supernova or ultraluminous X-ray source, based on the observed long-term behavior of the X-ray and radio emission, while the observed X-ray variability is consistent with the behavior of well-studied AGNs.Comment: 7 pages, 4 figures, 2 tables; accepted for publication in Ap

Evaluating The Effect Of Alternative Carbon Allocation Schemes In A Land Surface Model (Clm4.5) On Carbon Fluxes, Pools And Turnover In Temperate Forests

How carbon (C) is allocated to different plant tissues (leaves, stem and roots) determines C residence time and thus remains a central challenge for understanding the global C cycle. We used a diverse set of observations (AmeriFlux eddy covariance tower observations, biomass estimates from tree-ring data, and Leaf Area Index (LAI) measurements) to compare C fluxes, pools, and LAI data with those predicted by a Land Surface Model (LSM), the Community Land Model (CLM4.5). We ran CLM for nine temperate (including evergreen and deciduous) forests in North America between 1980 and 2013 using four different C allocation schemes: i) Dynamic C allocation scheme (named D-CLM ) with one dynamic allometric parameter, which allocates C to the stem and leaves to vary in time as a function of annual Net Primary Production (NPP). ii) An alternative dynamic C allocation scheme (named D-Litton ), where, similar to (i) C allocation is a dynamic function of annual NPP, but unlike (i) includes two dynamic allometric parameters involving allocation to leaves, stem and coarse roots iii–iv) Two fixed C allocation schemes, one representative of observations in evergreen (named F-Evergreen ) and the other of observations in deciduous forests (named F-Deciduous ). D-CLM generally overestimated Gross Primary Production (GPP) and ecosystem respiration, and underestimated Net Ecosystem Exchange (NEE). In D-CLM, initial aboveground biomass in 1980 was largely overestimated (between 10527 and 12897 g Cm-2) for deciduous forests, whereas aboveground biomass accumulation through time (between 1980 and 2011) was highly underestimated (between 1222 and 7557 g Cm-2) for both evergreen and deciduous sites due to a lower stem turnover rate in the sites than the one used in the model. D-CLM overestimated LAI in both evergreen and deciduous sites because the leaf C-LAI relationship in the model did not match the observed leaf C-LAI relationship at our sites. Although the four C allocation schemes gave similar results for aggregated C fluxes, they translated to important differences in long-term aboveground biomass accumulation and aboveground NPP. For deciduous forests, D-Litton gave more realistic Cstem/Cleaf ratios and strongly reduced the overestimation of initial aboveground biomass, and aboveground NPP for deciduous forests by D-CLM. We identified key structural and parameterization deficits that need refinement to improve the accuracy of LSMs in the near future. That could be done by addressing some of the current model assumptions about C allocation and the associated parameter uncertainty. Our results highlight the importance of using aboveground biomass data to evaluate and constrain the C allocation scheme in the model, and in particular, the sensitivity to the stem turnover rate. Revising these will be critical to improving long-term C processes in LSMs, and improve their projections of biomass accumulation in forests

Validating the Fitbit Charge 4© wearable activity monitor for use in physical activity interventions

OBJECTIVES: Commercially available wearable activity monitors can promote physical activity behaviour. Clinical trials typically quantify physical activity with research grade activity monitors prior to testing interventions utilising commercially available wearable activity monitors aimed at increasing step count. Therefore, it is important to test the agreement of these two types of activity monitors.OBJECTIVES: Observational.METHODS: Thirty adults (20-65 years, n = 19 females) were provided a Fitbit Charge 4©. To determine reliability using an intraclass correlation coefficient, two, one-minute bouts of treadmill walking were performed at a self-selected pace. Subsequently, participants wore both an ActiGraph wGT3X-BT and the Fitbit for seven days. To determine agreement, statistical equivalence and the mean absolute percentage error were calculated and represented graphically with a Bland-Altman plot. Ordinary least products regression was performed to identify fixed or proportional bias.RESULTS: The Fitbit showed 'good' step count reliability on the treadmill (intraclass correlation coefficient = 0.75, 95 % CI = 0.53-0.87, p &lt; 0.001). In free-living however, it overestimated step count when compared to the ActiGraph wGT3X-BT (mean absolute percentage error = 26.02 % ± 14.63). Measurements did not fall within the ± 10 % equivalence region and proportional bias was apparent (slope 95 % CI = 1.09-1.35).CONCLUSIONS: The Fitbit Charge 4© is reliable when measuring step count on a treadmill. However, there is an overestimation of daily steps in free-living environments which may falsely indicate compliance with physical activity recommendations.</p

Exposure to CO2 influences metabolism, calcification and gene expression of the thecosome pteropod Limacina retroversa

Author Posting. © The Company of Biologists, 2018. This article is posted here by permission of The Company of Biologists for personal use, not for redistribution. The definitive version was published in Journal of Experimental Biology 221 (2018): jeb164400, doi:10.1242/jeb.164400.Thecosomatous pteropods, a group of aragonite shell-bearing zooplankton, are becoming an important sentinel organism for understanding the influence of ocean acidification on pelagic organisms. These animals show vulnerability to changing carbonate chemistry conditions, are geographically widespread, and are both biogeochemically and trophically important. The objective of this study was to determine how increasing duration and severity of CO2 treatment influence the physiology of the thecosome Limacina retroversa, integrating both gene expression and organism-level (respiration and calcification) metrics. We exposed pteropods to over-saturated, near-saturated or under-saturated conditions and sampled individuals at 1, 3, 7, 14 and 21 days of exposure to test for the effect of duration. We found that calcification was affected by borderline and under-saturated conditions by week two, while respiration appeared to be more strongly influenced by an interaction between severity and duration of exposure, showing complex changes by one week of exposure. The organismal metrics were corroborated by specific gene expression responses, with increased expression of biomineralization-associated genes in the medium and high treatments throughout and complex changes in metabolic genes corresponding to both captivity and CO2 treatment. Genes associated with other physiological processes such as lipid metabolism, neural function and ion pumping had complex responses, influenced by both duration and severity. Beyond these responses, our findings detail the captivity effects for these pelagic organisms, providing information to contextualize the conclusions of previous studies, and emphasizing a need for better culturing protocols.Funding for this research was provided by a National Science Foundation grant to G.L.L., A.E.M. and A.M.T. (OCE-1316040). Additional support for field sampling was provided by theWoods Hole Oceanographic Institution, Coastal Ocean Institute and the Pickman Foundation.2019-02-1

The effect of elevated carbon dioxide on the sinking and swimming of the shelled pteropod Limacina retroversa

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in ICES Journal of Marine Science 74 (2017): 1893–1905, doi:10.1093/icesjms/fsx008.Shelled pteropods are planktonic molluscs that may be affected by ocean acidification. Limacina retroversa from the Gulf of Maine were used to investigate the impact of elevated carbon dioxide (CO2) on shell condition as well as swimming and sinking behaviours. Limacina retroversa were maintained at either ambient (ca. 400 μatm) or two levels of elevated CO2 (800 and 1200 μatm) for up to four weeks, and then examined for changes in shell transparency, sinking speed, and swimming behaviour assessed through a variety of metrics (e.g., speed, path tortuosity, wing beat frequency). After exposures to elevated CO2 for as little as four days, the pteropod shells were significantly darker and more opaque in the elevated CO2 treatments. Sinking speeds were significantly slower for pteropods exposed to medium and high CO2 in comparison to the ambient treatment. Swimming behaviour showed less clear patterns of response to treatment and duration of exposure, but overall, swimming did not appear to be hindered under elevated CO2. Sinking is used by L. retroversa for predator evasion, and altered speeds and increased visibility could increase the susceptibility of pteropods to predation.Funding for this research was provided by a National Science Foundation grant to Lawson, Maas, and Tarrant (OCE-1316040). Additional support for field sampling was provided by the WHOI Coastal Ocean Institute, Pickman Foundation, and the Tom Haas Fund at the New Hampshire Charitable Foundation