1,113 research outputs found
What Can Your Computer Recognize: Chemical and Facial Pattern Recognition Through the Use of the Eigen Analysis Method
Seeing patterns in the world is part of the human condition. If the numbers 2, 4, 6, 8,... are put before someone they will readily recognize the pattern of counting by two and be able to continue the sequence with the number 10, 12, . . . . Similarly, someone who is moderately acquainted with mathematics would recognize the numbers 0, 1, 1, 2, 3, 5, 8,... as the Fibonacci sequence. Yet, patterns are not simply limited to what can be observed within mathematical relationships. Yet, while humans can identify the pattern found within the frieze, a computer could not perform the same recognition with the ease or sophistication inherent to the human mind. Even the seemingly simple act of reading and comprehending the sentences on a page is an example of pattern recognition that can be performed with a sense of effortlessness by a human, but with only moderate success by a computer
The Unevolved Main Sequence of Nearby Field Stars and the Open Cluster Distance Scale
The slope and zero-point of the unevolved main sequence as a function of
metallicity are investigated using a homogeneous catalog of nearby field stars
with absolute magnitudes defined with revised Hipparcos parallaxes, Tycho-2
photometry, and precise metallicities from high-dispersion spectroscopy.
(B-V)-temperature relations are derived from 1746 stars between [Fe/H] = -0.5
and +0.6 and 372 stars within 0.05 dex of solar abundance; for T_e = 5770 K,
the solar color is B-V= 0.652 +/- 0.002 (s.e.m.). From over 500 cool dwarfs
between [Fe/H] = -0.5 and +0.5, Delta(B-V)/Delta[Fe/H] at fixed M_V = 0.213 +/-
0.005, with a very weak dependence upon the adopted main sequence slope with
B-V at a given [Fe/H]. At Hyades metallicity this translates into Delta
M_V/Delta[Fe/H] at fixed B-V = 0.98 +/- 0.02, midway between the range of
values empirically derived from smaller and/or less homogeneous samples and
model isochrones. From field stars of similar metallicity, the Hyades ([Fe/H] =
+0.13) with no reddening has (m-M)_0 = 3.33 +/- 0.02 and M67, with E(B-V) =
0.041, A_V = 3.1E(B-V), and [Fe/H] = 0.00, has (m-M)_0 = 9.71 +/- 0.02 (s.e.m),
where the errors quoted refer to internal errors alone. At the extreme end of
the age and metallicity scale, with E(B-V) = 0.125 +/- 0.025 and [Fe/H] = +0.39
+/- 0.06, comparison of the fiducial relation for NGC 6791 to 19 field stars
with (B-V) above 0.90 and [Fe/H] = +0.25 or higher, adjusted to the metallicity
of NGC 6791, leads to (m-M)_0 = 13.07 +/- 0.09, internal and systematic errors
included.Comment: 32 pages, 8 eps figures, latex; accepted for PAS
Patient Perspectives on Adherence to the New Hepatitis C Antiviral Medications: ‘A New Lease on Life’
This study explored patients’ perspectives about taking the new direct-acting antivirals (DAAs) for the treatment of Hepatitis C (i.e., sofosbuvir, simeprevir, ledipasvir/sofosbuvir, ombitasvir/paritraprevir/ritonavir and dasabuvir) to identify facilitators of medication adherence. The project was conducted using semi-structured interviews with 12 Veterans who successfully completed a treatment course on the new DAAs. The Veterans were recruited using purposive sampling. The data collected from the semi-structured interviews was analyzed using an adapted open coding method outlined by Auerbach and Silverstein (2003), with identification of relevant text sub-grouped into repeating ideas, and then creation of overarching themes and constructs. Results obtained provide insight into factors that influenced the Veterans’ medication adherence during the course of treatment. Key constructs, embodying major themes supported by repeating ideas, included recognizing the “burden of HCV,” the importance of the “treatment engagement process,” and anticipation of “positive outcomes.” Clinical implications are discussed
A vortex population viability analysis model for the Chacoan peccary (catagonus wagneri)
El quimilero o taguá (Catagonus wagneri) es una especie amenazada, endémica del Chaco Seco, para la cual disponemos de poca información. Para estimar cuantitativamente el riesgo de disminución y extinción de sus poblaciones silvestres generamos modelos de viabilidad poblacional. Con estos modelos matemáticos se pueden identificar factores naturales y antrópicos complejos que interactúan y que influyen en la persistencia y la salud de una población. Los modelos también se pueden utilizar para evaluar los efectos de diferentes estrategias de gestión, permitiendo identificar las acciones de conservación más efectivas para una población o especie. Además, estos modelos se pueden usar para identificar las necesidades de investigación debido a que ponen en evidencia los vacíos de información sobre la especie. Utilizando estos modelos, evaluamos la proyección poblacional en las condiciones actuales y en comparación con posibles variaciones existentes en el sistema. Para generar los parámetros ingresados en los modelos realizamos una reunión de especialistas y una revisión bibliográfica. Trabajó con valores de línea de base (base), mínimos (mín.) y máximos (máx.). Generamos diferentes modelos ante diferentes escenarios y testeamos la sensibilidad a la incertidumbre de cada modelo. Esto permitió establecer prioridades de investigación. Además, determinamos los tamaños mínimos de población viable considerando la incertidumbre y analizamos los posibles efectos de la caza en una población de esta especie.Fil: Leus, Kritin. International Union for Conservation of Nature. Species Survival Commission; DinamarcaFil: Altrichter, Mariana. International Union for Conservation of Nature. Species Survival Commission; Estados UnidosFil: Desbiez, Arnaud. International Union for Conservation of Nature. Species Survival Commission; BrasilFil: Camino, Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Giordano, Anthony J.. S.P.E.C.I.E.S.; Estados UnidosFil: Campos Krauer, Juan Manuel. University of Florida. Department of Wildlife Ecology and Conservation; Estados Unidos. Centro Chaqueño para la Conservación y la Investigación; ParaguayFil: Brooks, Daniel M.. Houston Museum Of Natural Science; Estados UnidosFil: Thompson, Jeffrey. Consejo Nacional de Ciencia y Tecnología; ParaguayFil: Núñez Regueiro, Mauricio Manuel. University of Florida. Department of Wildlife Ecology and Conservation; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Livestock Depredation by Leopards, Associated Economic Losses, and Financial Compensation to Communities in Chhota Udepur District of Central Gujarat, India
Livestock depredation by large carnivores has been documented across the entire Indian subcontinent. The failure of managers to mitigate livestock losses in landscapes dependent on subsistence agriculture poses a threat to the conservation of carnivores. For much of Gujarat, a western Indian state characterized by extensive semi-arid habitats, the Indian leopard (Panthera pardus fusca) is considered an apex predator. Increasing regional leopard populations in response to protection efforts has led to more attacks on humans, along with an increase in rates of livestock depredation. In many cases, the regional forest department financially compensates livestock owners for depredation caused by leopards. Herein, we report on data we collected on leopard-caused livestock depredations in the Chhota Udepur district of Gujarat for 2019–2020. Between November 2020 and March 2021, we recorded 104 distinct cases of leopard depredations that resulted in 134 livestock mortalities. Most attacks occurred in the middle of the night, with the greatest frequency occurring between 2100 and 0400 hours (n = 53). Interestingly, livestock depredations by leopards appeared to occur more in the monsoon season (66%) than during the drier seasons (Fisher’s least significant difference [LSD], P \u3c 0.05). We also found that not everyone enduring losses to leopards received full compensation for the value of their animals. Livestock kept in corrals at night were more vulnerable to leopard attack (R2 = 38.6, P = 0.01) compared to free-ranging livestock foraging by day in farms and forests. We recommend that livestock compensation claims filed by communities be investigated and processed quickly and that compensation be based on fair value for domestic animals lost. To better understand the drivers of human–leopard conflict, we also encourage rigorous surveys of potential leopard prey species in forested areas adjacent to conflict hotspots as well as research to identify the most effective methods communities might use to safeguard their livestock
Integrating robotics into wildlife conservation: testing improvements to predator deterrents through movement
Background Agricultural and pastoral landscapes can provide important habitat for wildlife conservation, but sharing these landscapes with wildlife can create conflict that is costly and requires managing. Livestock predation is a good example of the challenges involving coexistence with wildlife across shared landscapes. Integrating new technology into agricultural practices could help minimize human-wildlife conflict. In this study, we used concepts from the fields of robotics (i.e., automated movement and adaptiveness) and agricultural practices (i.e., managing livestock risk to predation) to explore how integration of these concepts could aid the development of more effective predator deterrents.
Methods We used a colony of captive coyotes as a model system, and simulated predation events with meat baits inside and outside of protected zones. Inside the protected zones we used a remote-controlled vehicle with a state-of-the art, commercially available predator deterrent (i.e., Foxlight) mounted on the top and used this to test three treatments: (1) light only (i.e., without movement or adaptiveness), (2) predetermined movement (i.e., with movement and without adaptiveness), and (3) adaptive movement (i.e., with both movement and adaptiveness). We measured the time it took for coyotes to eat the baits and analyzed the data with a time-to-event survival strategy.
Results Survival of baits was consistently higher inside the protected zone, and the three movement treatments incrementally increased survival time over baseline except for the light only treatment in the nonprotected zone. Incorporating predetermined movement essentially doubled the efficacy of the light only treatment both inside and outside the protected zone. Incorporating adaptive movement exponentially increased survival time both inside and outside the protected zone. Our findings provide compelling evidence that incorporating existing robotics capabilities (predetermined and adaptive movement) could greatly enhance protection of agricultural resources and aid in the development of nonlethal tools for managing wildlife. Our findings also demonstrate the importance of marrying agricultural practices (e.g., spatial management of livestock at night) with new technology to improve the efficacy of wildlife deterrents
The Importance of Unprotected Areas as Habitat for The Leopard Cat (Prionailurus bengalensis javanensis Desmarest, 1816) on Java, Indonesia
Protected areas play important roles for protecting many endangered species in Indonesia. However, very limited information regarding roles of protected areas and non-protected areas for supporting the habitat of less-concerned carnivores in Java, leopard cat (Prionailurus bengalensis javanensis). We aim to assess the relative roles of non-protected areas for the habitat of this cat on the highly fragmented and populated island of Java. We develop species distribution modelling, using Maxent by integrating various sources of presence data of this species and environmental data. Our finding confirms that leopard cat can life in various habitat types but mainly patchy forest areas. While most of the protected areas are suitable for the habitat of this smallest cat on Java, the non-protected areas provide much larger areas for its habitat (66.8 %). Our findings highlighted the importance of maintaining connectivity among habitat patches in non-protected areas, habitat protection using current government policy on high conservation value forest and essential ecosystems areas. Pentingnya Kawasan Non Lindung sebagai Habitat Kucing Hutan (Prionailurus bengalensis javanensis Desmarest, 1816) di Jawa, IndonesiaIntisariKawasan lindung memainkan peran penting dalam melindungi banyak spesies yang terancam punah di Indonesia. Walaupun demikian, informasi mengenai peran kawasan lindung dan kawasan non lindung untuk mendukung habitat karnivora yang kurang mendapat perhatian di Jawa, kucing hutan (Prionailurus bengalensis javanensis), sangat terbatas. Penelitian ini bertujuan untuk menilai peran kawasan non lindung sebagai habitat kucing hutan di Pulau Jawa, pulau yang sangat terfragmentasi dan padat penduduk. Kami mengembangkan pemodelan distribusi spesies, menggunakan Maxent dengan mengintegrasikan berbagai sumber data kehadiran spesies kucing hutan dan data lingkungan. Temuan kami menegaskan bahwa kucing hutan dapat hidup di berbagai jenis habitat tetapi habitat utamanya adalah kawasan hutan yang agak terbuka. Meskipun sebagian besar kawasan lindung sesuai untuk habitat kucing terkecil di Jawa ini, kawasan non lindung justru menyediakan area yang jauh lebih besar untuk habitat kucing hutan (66,8 %). Temuan kami juga menyoroti pentingnya menjaga konektivitas antar habitat di kawasan non lindung dan perlindungan habitat dengan menggunakan kebijakan pemerintah saat ini tentang hutan Bernilai Konservasi Tinggi dan Kawasan Ekosistem Esensial
Quantifying Wildlife Use of Escape Ramps Along a Fenced Highway
Wildlife exclusion fencing can significantly reduce wildlife–vehicle collisions. However, some animals breach the fence and become trapped in the highway corridor, thereby increasing risk of a wildlife–vehicle collision. An emerging solution to this problem is the installation of earthen escape ramps (i.e., jumpouts), which allow trapped animals to escape the highway corridor. Few studies have quantified wildlife use of jumpouts, and none have investigated intraspecific differences in use. We used camera traps to document wildlife use of 4 2m-high jumpouts associated with wildlife exclusion fencing along Highway 101 near San Luis Obispo, California, USA, from 2012 to 2017. We surveyed for 7,361 nights across all 4 jumpouts, yielding 1,015 visitation events by 10 different species of large- and medium-sized mammals. Mule deer (Odocoileus hemionus) accounted for 895 (88%) detections; they jumped out 20% of the time when detected at the top of the ramp and were never detected using the jumpout to enter the highway corridor. We differentiated male and female deer using the presence of antlers and found that they jumped out at similar rates, but females were detected 6 times more often and were more likely to return to the same jumpout. Two groups of 2–3 deer accounted for ~41% of deer detections, which allowed us to investigate their behavior over time. These results indicate that individual variation could influence jumpout use, which should be considered when quantifying their use. To increase the overall jumpout rate, we recommend a jumpout height between 1.75 and 2 m
Achieving conservation through cattle ranching: The case of the Brazilian Pantanal
Cattle ranching in the ~140,000 km2 Brazilian Pantanal is considered one of the most important cases of sustainable use of natural resources in the global south. The region has had a successful history of balancing environmental protection with the production of >3.8 million cattle. However, global change, infrastructure projects, and deforestation, threaten the sustainable use of the Pantanal. Here, using Ostrom's design principles as a framework, we interviewed 49 local stakeholders and conducted a review of secondary information aiming to evaluate the sustainability of cattle ranching practices across the region and the threats to it. We show that well-defined property boundaries, congruence between appropriation and provision rules through low-intensity cattle ranching, and co-management of resources, are all key components for achieving sustainability in the Pantanal. However, we documented shortcomings in satisfying critical aspects of Orstrom's design principles. Specifically, we argue that the Pantanal needs better biodiversity and behavior monitoring, the creation of platforms or mechanisms to solve local conflicts around resource access and use, recognition by governments and international bodies of the local efforts to promote local sustainability, and the creation of networks effectively connecting existing sustainability initiatives
A perspective on using experiment and theory to identify design principles in dye-sensitized solar cells
Dye-sensitized solar cells (DSCs) have been the subject of wide-ranging studies for many
years because of their potential for large-scale manufacturing using roll-to-roll processing
allied to their use of earth abundant raw materials. Two main challenges exist for DSC
devices to achieve this goal; uplifting device efficiency from the 12 to 14% currently
achieved for laboratory-scale ‘hero’ cells and replacement of the widely-used liquid
electrolytes which can limit device lifetimes. To increase device efficiency requires optimized
dye injection and regeneration, most likely from multiple dyes while replacement
of liquid electrolytes requires solid charge transporters (most likely hole transport materials
– HTMs). While theoretical and experimental work have both been widely applied to
different aspects of DSC research, these approaches are most effective when working in
tandem. In this context, this perspective paper considers the key parameters which
influence electron transfer processes in DSC devices using one or more dye molecules
and how modelling and experimental approaches can work together to optimize electron
injection and dye regeneration.
This paper provides a perspective that theory and experiment are best used in tandem to study
DSC device
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