Obstructions for Bounded Branch-depth in Matroids

DeVos, Kwon, and Oum introduced the concept of branch-depth of matroids as a natural analogue of tree-depth of graphs. They conjectured that a matroid of sufficiently large branch-depth contains the uniform matroid Un;2n or the cycle matroid of a large fan graph as a minor. We prove that matroids with sufficiently large branch-depth either contain the cycle matroid of a large fan graph as a minor or have large branch-width. As a corollary, we prove their conjecture for matroids representable over a fixed finite field and quasi-graphic matroids, where the uniform matroid is not an option.

Testing the climate intervention potential of ocean afforestation using the Great Atlantic Sargassum Belt

Ensuring that global warming remains <2 °C requires rapid CO2 emissions reduction. Additionally, 100–900 gigatons CO2 must be removed from the atmosphere by 2100 using a portfolio of CO2 removal (CDR) methods. Ocean afforestation, CDR through basin-scale seaweed farming in the open ocean, is seen as a key component of the marine portfolio. Here, we analyse the CDR potential of recent re-occurring trans-basin belts of the floating seaweed Sargassum in the (sub)tropical North Atlantic as a natural analogue for ocean afforestation. We show that two biogeochemical feedbacks, nutrient reallocation and calcification by encrusting marine life, reduce the CDR efficacy of Sargassum by 20–100%. Atmospheric CO2 influx into the surface seawater, after CO2-fixation by Sargassum, takes 2.5–18 times longer than the CO2-deficient seawater remains in contact with the atmosphere, potentially hindering CDR verification. Furthermore, we estimate that increased ocean albedo, due to floating Sargassum, could influence climate radiative forcing more than Sargassum-CDR. Our analysis shows that multifaceted Earth-system feedbacks determine the efficacy of ocean afforestation.

Potential Pb+2 mobilization, transport, and sequestration in shallow aquifers impacted by multiphase CO2 leakage: a natural analogue study from the Virgin River Basin in Southwest Utah

Geological carbon sequestration (GCS) is necessary to help meet emissions reduction goals, but groundwater contamination may occur if CO2 and/or brine were to leak out of deep storage formations into the shallow subsurface. For this study, a natural analogue was investigated: in the Virgin River Basin of southwest Utah, water with moderate salinity and high CO2 concentrations is leaking upward into shallow aquifers that contain heavy metal-bearing concretions. The aquifer system is comprised of the Navajo and Kayenta formations, which are pervasive across southern Utah and have been considered as a potential GCS injection unit where they are sufficiently deep. Numerical models of the site were constructed based on measured water chemistry and head distributions from previous studies. Simulations were used to improve understanding of the rate and distribution of the upwelling flow into the aquifers, and to assess the reactive transport processes that may occur if the upwelling fluids were to interact with a zone of iron oxide and other heavy metals, representing the concretions that are common in the area. Various mineralogies were tested, including one in which Pb+2 was adsorbed onto ferrihydrite, and another in which it was bound within a solid mixture of litharge (PbO) and hematite (Fe2O3). Results indicate that metal mobilization depends strongly on the source zone composition and that Pb+2 transport can be naturally attenuated by gas phase formation and carbonate mineral precipitation. These findings could be used to improve risk assessment and mitigation strategies at geological carbon sequestration sites.Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage

Analytic Automorphisms and Transitivity of Analytic Mappings

In this paper, we investigate analytic automorphisms of complex topological vector spaces and their applications to linear and nonlinear transitive operators. We constructed some examples of polynomial automorphisms that show that a natural analogue of the Jacobian Conjecture for infinite dimensional spaces is not true. Also, we prove that any separable Fréchet space supports a transitive analytic operator that is not a polynomial. We found some connections of analytic automorphisms and algebraic bases of symmetric polynomials and applications to hypercyclicity of composition operators.

Analytic Automorphisms and Transitivity of Analytic Mappings

In this paper we investigate analytic automorphisms of complex topological vector spaces and their applications to linear and nonlinear transitive operators. We constructed some examples of polynomial automorphisms which show that a natural analogue of the Jacobian Conjecture for infinite dimensional spaces is not true. Also, we prove that any separable Fréchet space supports a transitive analytic operator which is not a polynomial. We found some connections of analytic automorphisms and algebraic bases of symmetric polynomials and applications to hypercyclisity of composition operators.

FASILITAS REKREASI INTERAKTIF TANAMAN HIAS DI KEDOYA UTARA

Urban life especially Jakarta is inseparable from daily activities such as work, school, etc. Routines that are carried out repeatedly cause people to become bored and stressed which affects their performance, therefore it is important to have activities like entertainment to relieve fatigue, and stress. In North Kedoya interaction between neighbors is very lacking because of reluctance and feel strange, lack of joint activities and places to interact causing contact between people become less, on the other hand kedoya district has potential that many ornamental plants sold and traded and cultivated, these plants become a special attraction in the area so Interactive Ornamental Plants Facility Project proposed to be able to accommodate the needs of local residents, and become a place for all people to meet and interact with each other by playing together while reviving the identity of ornamental plants in the region. Project programs such as multipurpose room, gallery of ornamental plants, ornamental plant installations, ornamental plant gardens, board games and tables games, dining areas integrated with ornamental plants, and virtual park. The design process uses phenomenological methods and biophilic design concepts by using 3 biophilic main principles Nature In Space, Natural Analogue, and Nature Of Space and using ornamental plants as its elements. It is hoped that this project can become a node to meet and interact not only with others but also with nature which can have a positive impact on health, comfort and provide entertainment for the residents of North Kedoya. Keywords: ornamental plants; interaction; interactive; north kedoya; recreation Abstrak Kehidupan perkotaan khususnya Jakarta tidak lepas dari kegiatan sehari - hari seperti bekerja, bersekolah, dan lain - lain. Rutinitas yang dilakukan berulang kali menyebabkan orang merasa jenuh dan stress yang kemudian berpengaruh bagi kinerja seseorang, maka dari itu penting adanya aktivitas yang bersifat hiburan untuk melepas penat, dan stress. Di Kedoya Utara interaksi antar sesama tetangga sangatlah kurang dikarenakan rasa enggan dan asing, kurang adanya aktivitas bersama dan tempat untuk berinteraksi menyebabkan kontak antar sesama menjadi kurang, di satu sisi kawasan kedoya ini sendiri memiliki potensi yaitu banyaknya tanaman hias yang di perjual belikan dan dibudidayakan, tanaman – tanaman ini menjadi daya tarik tersendiri di kedoya sehingga diusulkan Proyek Fasilitas Rekreasi Interaktif Tanaman Hias menjadi tempat untuk dapat mewadahi kebutuhan warga setempat khususnya yang bersifat hiburan dan menjadi tempat bagi semua kalangan untuk bertemu dan saling berinteraksi dengan bermain bersama sekaligus menghidupkan identitas tanaman hias pada kawasan. Program proyek berupa ruang serba guna, gallery tanaman hias kering, instalasi tanaman hias, taman tanaman hias, area permainan papan dan meja, tempat makan yang terintegrasi dengan tanaman hias, dan taman virtual. Proses perancangan menggunakan metode fenomenologi dan konsep desain biofilik dengan mengambil 3 prinsip utamanya yaitu Nature In Space, Natural Analogue, dan Nature Of Space dan menggunakan tanaman hias sebagai elemennya. Diharapkan proyek ini dapat menjadi titik simpul untuk bertemu dan berinteraksi tidak hanya dengan sesama namun juga dengan alam yang dapat berdampak positif bagi kesehatan, kenyamanan dan memberikan hiburan bagi warga Kedoya Utara.