Optimal strategies to protect a sub-population at risk due to an established epidemic

Epidemics can particularly threaten certain sub-populations. For example, for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the elderly are often preferentially protected. For diseases of plants and animals, certain sub-populations can drive mitigation because they are intrinsically more valuable for ecological, economic, socio-cultural or political reasons. Here, we use optimal control theory to identify strategies to optimally protect a ‘high-value’ sub-population when there is a limited budget and epidemiological uncertainty. We use protection of the Redwood National Park in California in the face of the large ongoing state-wide epidemic of sudden oak death (caused by Phytophthora ramorum ) as a case study. We concentrate on whether control should be focused entirely within the National Park itself, or whether treatment of the growing epidemic in the surrounding ‘buffer region’ can instead be more profitable. We find that, depending on rates of infection and the size of the ongoing epidemic, focusing control on the high-value region is often optimal. However, priority should sometimes switch from the buffer region to the high-value region only as the local outbreak grows. We characterize how the timing of any switch depends on epidemiological and logistic parameters, and test robustness to systematic misspecification of these factors due to imperfect prior knowledge.

Optimal strategies to protect a sub-population at risk due to an established epidemic

Epidemics can particularly threaten certain sub-populations. For example, for SARS-CoV-2, the elderly are often preferentially protected. For diseases of plants and animals, certain sub-populations can drive mitigation because they are intrinsically more valuable for ecological, economic, socio-cultural or political reasons. Here we use optimal control theory to identify strategies to optimally protect a “high value” sub-population when there is a limited budget and epidemiological uncertainty. We use protection of the Redwood National Park in California in the face of the large ongoing state-wide epidemic of sudden oak death (caused by Phytophthora ramorum) as a case study. We concentrate on whether control should be focused entirely within the National Park itself, or whether treatment of the growing epidemic in the surrounding “buffer region” can instead be more profitable. We find that, depending on rates of infection and the size of the ongoing epidemic, focusing control on the high value region is often optimal. However, priority should sometimes switch from the buffer region to the high value region only as the local outbreak grows. We characterise how the timing of any switch depends on epidemiological and logistic parameters, and test robustness to systematic misspecification of these factors due to imperfect prior knowledge.

Un-used Bank Capital Buffers and Credit Supply Shocks at SMEs during the Pandemic

Did banks curb lending to creditworthy small and mid-sized enterprises (SME) during the COVID-19 pandemic? Sitting on top of minimum capital requirements, regulatory capital buffers introduced after the 2008 global financial crisis (GFC) are costly regions of "rainy day" equity capital designed to absorb losses and provide lending capacity in a downturn. Using a novel set of confidential loan level data that includes private SME firms, we show that "buffer-constrained" banks (those entering the pandemic with capital ratios close to this regulatory buffer region) reduced loan commitments to SME firms by an average of 1.4 percent more (quarterly) and were 4 percent more likely to end pre-existing lending relationships during the pandemic as compared to "buffer-unconstrained" banks (those entering the pandemic with capital ratios far from the regulatory capital buffer region). We further find heterogenous effects across firms, as buffer-constrained banks disproportionately curtailed credit to three types of borrowers: (1) private, bank-dependent SME firms, (2) firms whose lending relationships were relatively young, and (3) firms whose pre-pandemic credit lines contractually matured at the start of the pandemic (and thus were up for renegotiation). While the post-2008 period saw the rise of banking system capital to historically high levels, these capital buffers went effectively unused during the pandemic. To the best of our knowledge, our study is the first to: (1) empirically test the usability of these Basel III regulatory buffers in a downturn, and (2) contribute a bank capital-based transmission channel to the literature studying how the pandemic transmitted shocks to SME firms.

STATUS KERENTANAN NYAMUK Aedes aegypti TERHADAP INSEKTISIDA SIPERMETRIN DI AREA PERIMETER DAN BUFFER PELABUHAN TANJUNG EMAS KOTA SEMARANG

An assessment of the use of insecticides needs to be done because of the threat of insecticide resistance problems in the application of vector control for dengue. A descriptive observational study was conducted to determine the susceptibility status of Ae. aegypti against 0.05% cypermethrin insecticide at Tanjung Emas Port, Semarang. The study was conducted using the WHO standard bioassay, biochemical, and molecular (PCR) assays. Interviews were conducted with selected respondents to find out the history of insecticide use. The results showed that the susceptibility status of the Aedes aegypti mosquito in the perimeter and buffer area with the WHO standard bioassay test was still vulnerable, with the mortality of Aedes aegypti samples collected from the two study sites being 100%. Biochemical tests showed that 0.05% cypermethrin was still susceptible to Ae. aegypti, with a yield of 100% mortality in both study areas. However, the results of the PCR test showed that homozygous resistance and heterozygous resistance were 80% and 20% respectively in the perimeter region, while in the buffer region it was 40% and 60%, respectively. The results of interviews with program managers showed that 100% of the officers had complied with the standard operating procedure for fogging activities with the insecticides used, i.e. malathion and cypermethrin. Both types of insecticides have been used on a rotational basis. However, the rotation of these insecticides has not been carried out routinely and periodically. Abstrak Evaluasi terhadap penggunaan insektisida perlu dilakukan karena adanya ancaman masalah resistensi insektisida dalam aplikasi program pengendalian vektor demam berdarah dengue. Studi observasional deskriptif dilakukan untuk melihat status kerentanan Aedes aegypti terhadap insektisida sipermetrin 0,05% di Pelabuhan Tanjung Emas Semarang. Studi menggunakan uji bioassay standar WHO, biokimia, dan molekuler (PCR). Kegiatan wawancara dilakukan pada responden terpilih untuk mengetahui riwayat penggunaan insektisida. Responden dalam penelitian ini adalah pengelola program dan masyarakat. Hasil penelitian menunjukkan Ae. aegypti di area perimeter dan buffer dengan uji bioassay standar WHO masih rentan, dengan kematian nyamuk uji yang dikoleksi dari dua lokasi studi masing-masing sebesar 100%. Uji biokimia menunjukkan bahwa sipermetrin 0,05% masih susceptible terhadap Ae. aegypti, dengan hasil sebesar 100% kematian di kedua area studi. Namun, uji PCR menunjukkan sudah terdapat proses mekanisme menuju resistensi dengan hasil resisten homozigot dan resisten heterozigot di area perimeter adalah 80% dan 20%, sedangkan area buffer adalah 40% dan 60%. Hasil wawancara dengan pengelola program menunjukkan 100% petugas sudah menerapkan standar, operasi, dan pelaksanaan kegiatan fogging dengan benar menggunakan insektisida bahan aktif malathion dan sipermetrin. Kedua jenis insektisida ini telah digunakan secara rotasi. Namun, rotasi insektisida tersebut belum dilakukan secara rutin dan berkala

Dietary habits of free-ranging banded langur (Presbytis femoralis) in a secondary-human modified forest in Johor, Malaysia

ABSTRACTBanded langurs, Presbytis femoralis, are distributed in southern Peninsular Malaysia, i.e., Johor and its borders including Singapore. It has been estimated that there are only < 250 mature individuals of P. femoralis in Malaysia and Singapore, and it is currently assessed as Critically Endangered. The dietary information of P. femoralis and even other closely related species has rarely been reported. This study, therefore, aimed to describe their dietary habits and discuss interaction between their feeding behaviour and its surrounding. This study was conducted from February to November 2018, with 15 sampling days each month. We collected a total of 186 sighting hours, using a scan sampling method with 10-min intervals, on a five-langur focal group. We have identified 29 species with 47 items consumed by the banded langur, mostly young leaves (51 %) followed by fruits (45 %), and flowers (3.8 %). The study group spent slightly more time consuming non-cultivated plants but relied on cultivated plants for the fruits. Over 75% of fruit feeding involved consuming cultivar plants; in most cases (73%), they ate only the pule, not the seeds. Since the cultivated plants was planted in human settlement, there is an urgent need to implement conservation measures to untangle the human-langur conflicts for instance, reforestation of a buffer region using non-cultivated plants. There is a potential for building upon our new findings with more detailed investigations, such as more extensive ecological factors influencing the dietary adaptation which would be necessary to support conservation efforts and management decisions of this species.

The Equilibrium Phase Formation and Thermodynamic Properties of Functional Tellurides in the Ag–Fe–Ge–Te System

Equilibrium phase formations below 600 K in the parts Ag2Te–FeTe2–F1.12Te–Ag2Te and Ag8GeTe6–GeTe–FeTe2–AgFeTe2–Ag8GeTe6 of the Fe–Ag–Ge–Te system were established by the electromotive force (EMF) method. The positions of 3- and 4-phase regions relative to the composition of silver were applied to express the potential reactions involving the AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 compounds. The equilibrium synthesis of the set of phases was performed inside positive electrodes (PE) of the electrochemical cells: (−)Graphite ‖LE‖ Fast Ag+ conducting solid-electrolyte ‖R[Ag+]‖PE‖ Graphite(+), where LE is the left (negative) electrode, and R[Ag+] is the buffer region for the diffusion of Ag+ ions into the PE. From the observed results, thermodynamic quantities of AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 were experimentally determined for the first time. The reliability of the division of the Ag2Te–FeTe2–F1.12Te–Ag2Te and Ag8GeTe6–GeTe–FeTe2–AgFeTe2–Ag8GeTe6 phase regions was confirmed by the calculated thermodynamic quantities of AgFeTe2, Ag2FeTe2, and Ag2FeGeTe4 in equilibrium with phases in the adjacent phase regions. Particularly, the calculated Gibbs energies of Ag2FeGeTe4 in two different adjacent 4-phase regions are consistent, which also indicates that it has stoichiometric composition.

Energy-Based Automatic Determination of Buffer Region in the Divide-and-Conquer Second-Order Møller-Plesset Perturbation Theory

In the linear-scaling divide-and-conquer (DC) electronic structure method, each subsystem is calculated together with the neighboring buffer region, the size of which affects the energy error introduced by the fragmentation in the DC method. The DC self-consistent field calculation utilizes a scheme to automatically determine the appropriate buffer region that is as compact as possible for reducing the computational time while maintaining acceptable accuracy (<i>J. Comput. Chem.</i> <b>2018</b>, <i>39</i>, 909). To extend the automatic determination scheme of the buffer region to the DC second-order Møller-Plesset perturbation (MP2) calculation, a scheme for estimating the subsystem MP2 correlation energy contribution from each atom in the buffer region is proposed. The estimation is based on the atomic orbital Laplace MP2 formalism. Based on this, an automatic buffer determination scheme for the DC-MP2 calculation is constructed and its performance for several types of systems is assessed.

Reactive Self-Collision Avoidance for a Differentially Driven Mobile Manipulator

This paper introduces a reactive self-collision avoidance algorithm for differentially driven mobile manipulators. The proposed method mainly focuses on self-collision between a manipulator and the mobile robot. We introduce the concept of a distance buffer border (DBB), which is a 3D curved surface enclosing a buffer region of the mobile robot. The region has the thickness equal to buffer distance. When the distance between the manipulator and mobile robot is less than the buffer distance, which means the manipulator lies inside the buffer region of the mobile robot, the proposed strategy is to move the mobile robot away from the manipulator in order for the manipulator to be placed outside the border of the region, the DBB. The strategy is achieved by exerting force on the mobile robot. Therefore, the manipulator can avoid self-collision with the mobile robot without modifying the predefined motion of the manipulator in a world Cartesian coordinate frame. In particular, the direction of the force is determined by considering the non-holonomic constraint of the differentially driven mobile robot. Additionally, the reachability of the manipulator is considered to arrive at a configuration in which the manipulator can be more maneuverable. In this respect, the proposed algorithm has a distinct advantage over existing avoidance methods that do not consider the non-holonomic constraint of the mobile robot and push links away from each other without considering the workspace. To realize the desired force and resulting torque, an avoidance task is constructed by converting them into the accelerations of the mobile robot. The avoidance task is smoothly inserted with a top priority into the controller based on hierarchical quadratic programming. The proposed algorithm was implemented on a differentially driven mobile robot with a 7-DOFs robotic arm and its performance was demonstrated in various experimental scenarios.